Spheroids are expected to aid the establishment of an in vitro-based cell culture system that can realistically reproduce cellular dynamics in vivo. We developed a fluoropolymer scaffold with an extracellular matrix (ECM) dot array and confirmed the possibility of mass-producing spheroids with uniform dimensions. Controlling the quality of ECM dots is important as it ensures spheroid uniformity, but issues such as pattern deviation and ECM drying persist in the conventional microstamping method. In this study, these problems were overcome via ECM dot printing using a resin mask with dot-patterned holes. For dot diameters of φ 300 μm, 400 μm, and 600 μm, the average spheroid diameters of human iPS cells (hiPSCs) were φ 260.8 μm, 292.4 μm, and 330.7 μm, respectively. The standard deviation when each average was normalized to 100 was 14.1%. A high throughput of 89.9% for colony formation rate to the number of dots and 89.3% for spheroid collection rate was achieved. The cells proliferated on ECM dots, and the colonies could be naturally detached from the scaffold without the use of enzymes, so there was almost no stimulation of the cells. Thus, the undifferentiated nature of hiPSCs was maintained until day 4. Therefore, this method is expected to be useful in drug discovery and regenerative medicine.

地域在住高齢女性11名（77.6 ± 7.1 歳）を対象にモトタイルを用いた運動を地域公民館において集団で週2 回，12 週間実施し，バランス能力への効果を検討した．バランス能力の指標には，開眼での20 秒間その場足踏みテスト（マーチテスト）を実施し，2 つの赤外線センサー機器を用いて頭部関節点の総軌跡長（TMD）と最大軌跡長（MMD）並びに膝関節点の軌跡長（KMD）の変化と両脚の歩調（PACE）とその変動係数（CV）を用いた．また，バランス能力に関連するパフォーマンステストのファンクショナルリーチ（FR），30 秒間チェアスタンド（30-CS），アップアンドゴー（TUG）も実施した．この結果，TMD，MMD，PACE 左脚CV およびTUG が運動後に有意に小さく，またFR，30-CS は有意に増加した．これらは，中程度以上の効果量が示された．他の赤外線センサー関連指標に有意な変化は認められなかったが，全体的にマーチテスト時の頭部関節点と膝関節点の揺れ，両脚を上げる際のバラツキが小さくなる傾向がみられた．以上から，モトタイルを用いた運動は，地域に在住する自立した高齢者のバランス能力改善のための運動の一つとして勧められる．

Establishing an in vitro–based cell culture system that can realistically simulate in vivo cell dynamics is desirable. It is thus necessary to develop a method for producing a large amount of cell aggregates (i.e., spheroids) that are uniform in size and quality. Various methods have been proposed for the preparation of spheroids; however, none of them satisfy all requirements, such as cost, size uniformity, and throughput. Herein, we successfully developed a new cell culture method by combining fluoropolymers and dot patterned extracellular matrix substrates to achieve size-controlled spheroids. First, the spheroids were spontaneously formed by culturing them two-dimensionally, after which the cells were detached with a weak liquid flow and cultured in suspension without enzyme treatment. Stable quality spheroids were easily produced, and it is expected that the introduction and running costs of the technique will be low; therefore, this method shows potential for application in the field of regenerative medicine.

PURPOSE: With a growing proportion of elderly people in the population, the maintenance of activities of daily living (ADLs) in elderly people is crucial to keep medical costs down. We investigated the ADL measurement accuracy of KINECTTM and Kinect Studio. To eliminate the subjectivity of conventional methods, we numerically assessed motions with computer analysis. METHODS: Eighteen actions that repeated "move" and "stationary" phases, including movement of arms, legs, head and torso were measured using KINECTTM. Errors and standard deviations of joint coordinates at the stationary points outputted from KINECT Studio were evaluated. Simultaneous measurements were performed with KINECTTM using conventional high-performance motion capture, and the output was treated as a true value for comparison. RESULTS: In most motions, errors of the joint coordinates were within 100 mm; however, there were two cases where errors due to the skeleton-model estimation by KINECT Studio increased. Firstly, when a part of the body unexpectedly moved out of the infrared measurable area, and secondly, when parts of the body overlapped each other on the KINECTTM image. CONCLUSIONS: KINECTTM and Kinect Studio are effective for ADL assessment when positions that cause large errors are excluded. Since KINECTTM has sufficient precision, it should also be possible to develop a more appropriate ADL evaluation system with a new algorithm of skeleton-model estimation that does not depend on KINECT Studio. Implications for Rehabilitation The KINECTTM and Kinect Studio are effective for ADL assessment when positions that cause large errors are excluded With an increasing proportion of elderly people in the population, the maintenance of activities of daily living (ADLs) in elderly people is crucial to keep medical costs down Systems such as the KINECTTM can support these goals.

The relation between O-2 pressure and composition in the pulsed-laser deposition of fluoroapatite was investigated using both on-axis and off-axis methods to determine the optimal conditions for obtaining a pure fluoroapatite film without OH groups. Through this, it was found that an O-2 pressure of 10 Pa, combined with an off-axis method, results in P/Ca and F/Ca values (0.6 and 0.2, respectively) that match closely with a stoichiometric composition of Ca-10(PO4)(6)F-2. Fourier transform infrared spectroscopy analysis confirmed that this optimized film was almost pure fluoroapatite, with no evidence of any OH groups originating from hydroxyapatite. X-ray diffraction also revealed that this fluoroapatite film crystallizes with a c-axis orientation perpendicular to its surface.

[Abstract]A fabrication technique for high temperature superconducting (HTS) nanowires has been developed to realize photon detectors operating at high temperatures. HTS nanowires based on YBa_2Cu_3O_y (YBCO) were fabricated by electron beam (EB) lithography and Ar ion milling. During the Ar ion milling. Duuribg the Ar iron milling process, the samples were cooles by liquid N_2 to suppress degradation of YBCO due to increasing temperature. The acceleration voltage of the samples were cooled by liquid N_2 to suppress degradation of YBCO due to increasing temperature. The acceleration voltage of the Ar ions was optimized to decrease the energy of ion bombardment. To reduce the degradation from the side edge of the YBCO nanowire, a dry process using oxygen ions was employed to remove the EB resist instead of a wet process with remover and rinse solutions. A YBCO nanowire 150 nm wide and 5.4 mm long was successfully fabricated by minimizing the degradation of the YBCO film quality during the fabrication process. [要旨]液体窒素温度以上の高温領域で動作する単一光子検出器の実現を目的として, 酸化物高温超伝導ナノワイヤーの作製方法について検討を行った. 電子ビームリソグラフィーでナノパターンを形成し, Arイオンエッチングを用いて酸化物高温超伝導薄膜のYBa_2Cu_3O_yに微細加工を施すことでナノワイヤーを作製した. Arプラズマのイオン衝撃による温度上昇は超伝導特性の劣化をもたらすため, これを防ぐ目的でArイオンエッチングを行う際に液体窒素で試料の冷却を行った. これと同時に, イオソ衝撃のエネルギーを抑えるため Arイオンの加速電圧の最適化も行った. 電子ビームレジストを除去する際のリムバーやリンスなどの液体を用いたウエットプロセスによっても, YBa_2Cu_3O_yナノワイヤーの側壁部に劣化を生じるため、その対策としてOイオンを用いたドライプロセスにより電子ビームレジストの除去を行う条件を見出した. その結果, 超伝導特性に殆ど劣化のない, ワイヤー幅150nm, ワイヤー長5.4mm の酸化物高温超伝導ナノワイヤーの実現に成功した.

Cell sheet technology is a scaffold-free method for tissue reconstruction. A sheet-shaped scaffold would be suitable for the regeneration of periodontal membrane. We designed a stem cell sheet combining human mesenchymal stromal cells (hMSCs) and a 10-mu m thick biological apatite (BAp) membrane fabricated with an ArF pulsed laser ablation for periodontal regeneration. X-ray diffraction showed that crystalline hydroxyapatite (HAp) was present in BAp and HAp membranes after post-annealing. Energy dispersive analysis of the BAp membrane revealed peaks of Na and Mg in addition to Ca and P. Approximately 3x10(4) hMSCs were cultured on BAp and HAP membranes for 7 and 14 days. From in vitro assays, hMSCs grew faster and had higher osteoblast differentiation when cultured on the BAp membrane than did the cell culture on the HAp membrane. Stem cell sheets combined with a BAp membrane may have potential applications in guided bone regeneration and osteoconductive scaffolds.

Dentin hypersensitivity is induced by mechanical stimuli or heat stimuli applied via dentin tubules exposed by lost of dental enamel or gingival recession. Common treatments for dentin hypersensitivity are resin coating or laser irradiation. However, these treatments have some problems such as poor biocompatibility or insufficient durability. We have been developing a treatment that creates artificial tooth enamel by attaching flexible ultrathin calcium phosphate sheet having a crystal structure similar to that of tooth enamel to seal the dentin tubules. In this study, the quantitative evaluation of dentin tubule sealing rate improved by attaching ultrathin amorphous calcium phosphate (ACP) sheet on human dentin is presented. The obtained sealing-rate by APC sheet application was 70.9 ±4.8%.

Er:YAGレーザーによるパルスレーザーアブレーション(PLD)法のターゲットにハイドロキシアパタイト(HAp)の前駆体のリン酸カルシウム系材料(DCPD、α-TCP、β-TCP、CPP)を用い、レーザー光を2分間照射した。乾燥状態ではDCPDが強いPLDを示し、α-TCPは弱いPLD、β-TCP、CPPでPLDを認めなかった。純水滴下後では全てに強いPLDを認めた。純水滴下後10分照射でTi基板上に成膜し、37℃の恒温槽に3時間保持した膜のX線回折(XRD)パターンでHApのピークを示したのはα-TCPのみであり、ピークは時間経過とともに小さくなり、48時間でほぼ消滅してHAp膜となった。エナメル質にpH5.5の第一リン酸カルシウム溶液を塗布してα-TCPをレーザーで成膜し、恒温槽保持3時間後のXRDパターンでピークは認めず、HAp膜となっていた。レジン包埋後断面の走査型電子顕微鏡像で、エナメル質上に10〜20μm厚の緻密なHAp膜を認め、成膜速度は約1〜2μm/minであった。

In this study, we prepared a uniaxially oriented oxide on a flexible polymer substrate. We first grew [100] oriented SrTiO3 (STO) on a MgO(100) substrate. After bonding the STO film to a poly(ethylene naphthalete) (PEN) sheet with a photoresist, we etched the MgO substrate with a phosphoric acid solution to transfer the oxide film to the PEN sheet. The thin (300nm) STO films did not crack after release, even after bending the sheet around a rod with a 1cm radius, while the thicker (800 nm) films did. Ultimately, this process could be adapted to prepare a flexible epitaxial oxide. (C) 2014 The Japan Society of Applied Physics

In this study, we prepared a uniaxially oriented oxide on a flexible polymer substrate. We first grew [100] oriented SrTiO3 (STO) on a MgO(100) substrate. After bonding the STO film to a poly(ethylene naphthalete) (PEN) sheet with a photoresist, we etched the MgO substrate with a phosphoric acid solution to transfer the oxide film to the PEN sheet. The thin (300nm) STO films did not crack after release, even after bending the sheet around a rod with a 1cm radius, while the thicker (800 nm) films did. Ultimately, this process could be adapted to prepare a flexible epitaxial oxide. (C) 2014 The Japan Society of Applied Physics

In order to impart both osseointegration and osteoconduction characteristics onto extruded pure polyetheretherketone (PEEK) for use as an artificial bone material, the surface of the PEEK was sputter-coated with a thin bilayer-film consisting of a commercially pure titanium (Ti) layer with a thickness of 90 nm and a hydroxyapatite layer with a thickness of 200 nm derived from simulated body fluid (SBF-HA). A specimen of PEEK coated only with Ti was used in peeling tests to determine the adhesive strength of the interface between the two materials, which was found to be 2.55 +/- 0.45 MPa. Tensile tests were also carried out, and it was found that no exfoliation of the Ti film occurred until an ultimate strain of 129% was reached. In a cell culture test using mouse osteoblast on the bilayer-coated PEEK, cell proliferation following 168 h of culturing was 1.3 times higher on the SBF-HA than on synthetic hydroxyapatite, and 2.4 times higher than that on the Ti-coated PEEK. In addition, the proliferation on the Ti-coated PEEK was 2.1 times higher than that on uncoated PEEK.

A technique to control the crystallinity of hydroxyapatite (HA) was investigated for applications such as dentistry, regenerative medicine, cell culture scaffolding, and bio-sensors. An amorphous HA film was first produced by pulsed laser deposition. After deposition, it was separated from a substrate as a free-standing sheet. Annealing was then performed to control the crystallinity of the sheet. It was found that conventional annealing in an electric oven was not suitable for HA sheets, because it led to curling and cracking. Since such problems were assumed to be caused by thermal stress, annealing was next carried out with the HA sheet enclosed in HA powder in the center of a metal capsule. This method allowed annealing to be successfully carried out without causing any curling or cracking. Uniform pieces with dimensions of 10 mm x 10 mm cut from a large HA sheet were annealed at temperatures of 200 to 800 degrees C and then examined using X-ray diffraction. It was found that the intensity of the diffraction peaks associated with crystalline HA changed with annealing temperature, and that the strongest peaks were observed for the sample annealed at 500 degrees C. These results indicate that the crystallinity of the HA sheet can be controlled using the proposed method.

A method of fabricating c-axis-oriented hydroxyapatite film on a quartz crystal microbalance (QCM) sensor was investigated. ZnO was used as a template to obtain a hexagonal hydroxyapatite crystal of uniaxial orientation. The ZnO was grown as a c-axis film on a Au/quartz with the surface structure of a QCM sensor. Under optimized conditions, hydroxyapatite was deposited by pulsed laser deposition. X-ray diffraction showed the hydroxyapatite film to be oriented along the c-axis. Because Au and ZnO are applied to many devices, the anisotropic properties of hydroxyapatite may be incorporated into these devices as well as QCM sensors. (C) 2013 The Japan Society of Applied Physics

Tooth enamel cannot be reconstructed once it is destroyed immoderately. Hydroxyapatite (HAp) thin sheet can potentially be used for a novel dental biomaterial to repair the enamel. Using a pulsed laser deposition (PLD) method, we have successfully created a flexible HAp sheet of less than a few micrometers in thickness. Due to its flexibility, the HAp sheet is tightly adhered on curved surfaces at the target site. In the present study, we newly developed double-layered sheets composed of HAp film coated with tricalcium phosphate (TCP) thin layer. The HAp/TCP sheet was adhered to the extracted human teeth using a calcium phosphate solution for 3 days. The adhesive strength between the HAp/TCP sheet and tooth enamel was evaluated by quasi-static tensile tests. Moreover, the interface structure between them was observed by a scanning electron microscopy. As a result of the mechanical evaluation, the adhesive strength was greater than approximately 2.5 MPa. The electron microscopic observation revealed that the sheet was partially fused with the enamel. These findings suggest the possibility that enamel defects are repaired using the HAp/TCP sheet for a short duration.

To develop an improved surface conformation of titanium web (TW) scaffold, we examined the in vitro and in vivo biocompatibility of a thin hydroxyapatite (HA) deposited by pulsed laser ablation. Thin HA film was deposited on titanium discs using an pulsed laser operating at a repletion rate of 10 Hz and annealed by heating at 380 degrees C for 1 h. The presence of HA not only along the surface but also in the TW inner region was confirmed by the elementary mapping of calcium, phosphorous, and titanium. X-ray diffraction pattern showed that crystalline HA was present in the HA coating. Microscopic images after actin staining with rhodamine phalloidin revealed that the spread of clonal stromal cells was markedly greater on HA coating than on untreated TW. When infused with clonal stromal cells, the HA-coated TW could indeed generate bone formation in the backs of nude mice. However, the appearance of new bone was not enhanced by the HA coating, likely because air in the porous scaffold during cell loading reduces the cell-scaffold contact. Mild vacuum loading techniques might enable differences of osteo-differentiation between HA-coated TW and non-coated TW to emerge.

我々は、可撓性を持つハイドロキシアパタイト(HAp)の薄いシートを人工エナメル質として用い、歯質表面に貼り付けたHApシートが唾液のみで歯質に接着することにより、エナメル質を再生させることを検討している。HApシートとエナメル質とを一体化させるために、口腔内で生じているエナメル質の脱灰・再石灰化に倣って、弱酸性リン酸カルシウム水溶液でシートを貼付することでシートとエナメル質の界面をまず脱灰し、その後人工唾液で再石灰化する方法で、これまで約1週間程度でHApシートとエナメル質は一体化することを確認した。今回はHApシートとエナメル質との一体化に要する時間をさらに短縮する目的で、HApシート表面にα-TCP薄膜を成膜したHAp/α-TCP複合シートを用いる方法を試みたので報告する。

We studied a method to obtain superconductivity even in very thin films of YBa2Cu3Oy (YBCO). These thinner YBCO films will be able to be applied to optics/superconductivity (opt/super) converters with high optical sensitivity. Opt/super converters composed of YBCO nano-bridges or nano-wires require a low critical current that is determined by the film thickness. According to X-ray diffraction, critical temperature (Tc) and residual resistivity ratio for the substrates of MgO (100), SrTiO 3 (100) and NdGaO3 (110), superconducting features are influenced by the lattice mismatching layer in YBCO closing to a hetero-epitaxy interface between YBCO and single crystal substrate. YBCO films with different thicknesses varying from 80 to 10 nm were prepared on SrTiO3, using a suitable temperature. The values of Tc slightly decreased when reducing YBCO thickness from 80 to 20 nm, and then declined sharply at less than 20 nm. It is considered that a layer in the beginning of deposition less than 20 nm causes stress in the crystal lattice. The Tc of 20 nm YBCO film on SrTiO3 was 80.8 K. It can work above liquid N2 temperature. © 2012 The Institute of Electrical Engineers of Japan.

To develop an improved surface conformation of titanium web (TW) scaffold, we examined the in vitro and in vivo biocompatibility of a thin hydroxyapatite (HA) deposited by pulsed laser ablation. Thin HA film was deposited on titanium discs using an pulsed laser operating at a repletion rate of 10 Hz and annealed by heating at 380°C for 1 h. The presence of HA not only along the surface but also in the TW inner region was confirmed by the elementary mapping of calcium, phosphorous, and titanium. X-ray diffraction pattern showed that crystalline HA was present in the HA coating. Microscopic images after actin staining with rhodamine phalloidin revealed that the spread of clonal stromal cells was markedly greater on HA coating than on untreated TW. When infused with clonal stromal cells, the HA-coated TW could indeed generate bone formation in the backs of nude mice. However, the appearance of new bone was not enhanced by the HA coating, likely because air in the porous scaffold during cell loading reduces the cell-scaffold contact. Mild vacuum loading techniques might enable differences of osteo-differentiation between HA-coated TW and non-coated TW to emerge. © 2012 The Hard Tissue Biology Network Association Printed in Japan, All rights reserved.

Before a tooth erupts, the ameloblasts are lost, which means that the tooth enamel does not regenerate itself after tooth eruption. In the present study, we attempt to regenerate the tooth enamel artificially using a flexible hydroxyapatite (HAp) sheet. First, a HAp film was deposited on a soluble substrate by pulsed laser deposition (PLD) using an ArF excimer laser. Next, the HAp film was collected as a freestanding sheet by dissolving the substrate using a solvent. The HAp sheet was adhered to the extracted human teeth using a calcium phosphate solution. The variation of the crystal structure of the HAp sheet with time was investigated by X-ray diffraction analysis. Furthermore, the variation in the mechanical characteristics with time between the HAp sheet and dental enamel were evaluated using tensile and scratch tests. The results suggest that the HAp sheet became fused to the tooth enamel within approximately one week. © (2012) Trans Tech Publications.

Objective: To impart rapid and durable osteoconductivity to implants, a commercial titanium screw implant was coated with stoichiometric hydroxyapatite (HA; 50 nm thick), and then with bovine hydroxyapatite (B-HA; 300 nm thick) using the pulsed laser deposition technique. As control specimens, a commercial implant coated with HA (20 mu m thick) using the flame spraying method (sprayed implant) and a simple titanium implant (basic implant) was used. Methods: The osteoconductivities of these three types of implant, after implantation for 4-24 weeks, were histologically evaluated. Results: Peeling of HA from the sprayed implant was observed by scanning electron microscopic observation. In the fourth postoperative week, the bilayered implant was already closely adhered to bone. On the other hand, the basic implant was surrounded by a gap containing connective tissue. With the sprayed implant, the bone adhered to the thick HA coating. Conclusion: The bilayer deposition technique supplies quick and long-term fixation of implants to bone, because the B-HA film dissolves to aid osteoconduction right immediately after implantation and the HA thin film maintains osteoconduction without dissolution. Neither of the thin-film fractures easily compared with thick coatings.

Lee, S, Islam, MM, Rogers, ME, Kusunoki, M, Okada, A, and Takeshima, N. Effects of hydraulic-resistance exercise on strength and power in untrained healthy older adults. J Strength Cond Res 25(4): 1089-1097, 2011-The purpose of this study was to determine the efficacy of hydraulic-resistance exercise (HDRE) in improving strength and power in healthy older adults. Thirty-nine older adults (68.6 +/- 4.9 years; 15 men, 24 women) were divided into a training group or control group (CON). Hydraulic-resistance exercise consisted of a 12-week supervised program, 50 min.d(-1), 3 d.wk(-1). Hydraulic-resistance exercise was used for 10 exercises: Chest press and pull, shoulder press and pull, low back flexion and extension squat, leg adduction/abduction, leg press, and elbow extension/flexion. The number of the sets and the hydraulic-resistance dial setting (D) were gradually increased in 3 stages during the 12-week program. Strength, rating of perceived exertion, and relative intensity during exercise increased significantly from stage to stage whereas repetition velocity decreased. Total work was higher in the second stage compared with the first but lower in the final stage because of reduced repetitions. Peak torque at D2 and D11 increased (p < 0.05) for knee extension (58 and 9%) and flexion (94 and 21%), chest press (35 and 12%) and pull (29 and 14%), shoulder press (14 and 18%) and pull (75 and 18%), and low back flexion (59 and 46%) and extension (84 and 34%). Peak power at D2 and D11 also increased (p, 0.05) for knee extension (140 and 26%) and flexion (96 and 36%), chest press (54 and 28%) and pull (62 and 23%), shoulder press (55 and 31%) and pull (159 and 30%), and low back flexion (177 and 127%) and extension (104 and 66%). There were no significant changes in the CON. Hydraulic-resistance exercise elicits significant improvements in strength and power in older adults. Therefore, HDRE is an effective form of resistance training that provides benefits using low and moderate intensity of training for older adults.

To enhance the sensitivities and antigen-binding capacities of immunosensors, oriented immobilization of antibodies on the surface of the sensor chip is critical, but to date, this has not been adequately achieved. We describe a way of adsorbing immunoglobulin (Ig) proteins onto 32-nm bio-nanocapsules (BNCs) through IgG Fc-binding domains derived from Staphylococcus aureus protein A (ZZ-BNC). This arrangement permits similar to 60 molecules of mouse total IgG bind to ZZ-BNC and all the IgG Fv regions to be displayed outwardly for the effective binding of antigens. ZZ-BNCs adsorbed onto the gold surface of the sensor chip of the quartz crystal microbalance (QCM) could markedly enhance the sensitivity and antigen-binding capacity of the chip. On the sensor chip of surface plasmon resonance (SPR), antibodies on the ZZ-BNCs showed higher affinities to each antigen than those on protein A. The BNC-coated sensor chip is very stable, and should prove useful for various immunosensor applications due to oriented immobilization of antibodies. (C) 2010 Elsevier Ltd. All rights reserved.

可撓性のハイドロキシアパタイト(HAp)シートを用いたエナメル質の再生を試みた。抜去ヒト歯を歯根歯冠境界部で切断して、露出したエナメル質を耐水研磨紙で研磨し、その上にリン酸カルシウム水溶液を用いてHApシートを貼付した。その後、人工唾液を1日1回塗布し、試料とした。HApシートを貼付して10分間乾燥させたのち、X線回折(XRD)パターンを順次測定するとともに、貼付後21日目におけるシートのエナメル質表面に対する固着応力を、3 mmφの引張り冶具を用いた引張り試験により評価した。XRDパターンより、約1週間程度でHApシートとエナメル質が一体化したことが示唆された。また、21日後の引張り試験では、3.4 MPaでシートに接着剤で固定していた治具がシートから剥がれたため、エナメル質上のシートの固着強度は3.4 MPa以上であることが明らかになった。

A freestanding hydroxyapatite (HAp) sheet of 5 similar to 10 mu m thickness was successfully prepared by a novel method. After depositing the thin HAp film on a soluble substrate by pulsed laser deposition (PLD) technique, the HAp film was collected as a freestanding sheet by dissolving the substrate using a solvent. Thereafter, HAp sheets were directly attached to enamel and dentin surfaces of extracted human teeth. Artificial saliva was sprayed every third day, and the course was observed for 90 days. Observation of the enamel-HAp and dentin-HAp interface by scanning electron microscopy revealed that the HAp sheet had stuck to the enamel and dentin surface.

ハイドロキシアパタイトの接着強度に対する膜厚と化学組成の影響について，ナノスクラッチ試験を用いて検討した。パルスレーザー堆積法を用いて医療用チタンを化学量論的ハイドロキシアパタイトと擬似体液由来アパタイトで被覆し，基材密着性と剥離挙動をナノスクラッチテストによって詳細に観察した．

A large hydroxyapatite (HA) sheet of 50 mm diameter was constructed using a new fabrication process. The HA sheet was prepared by pulsed laser deposition (PLD) and then separated from the substrate. An intermediate layer of spin-coated photoresist between the PLD film and the substrate was dissolved in acetone to enable the separation. Sufficient crystallinity was obtained after postannealing. The area of the HA sheet prepared by the proposed process was approximately 20 times larger than that of the HA sheet prepared by the previous process. The proposed process can also be used for larger sheets. The HA sheet has promise in medical and dental applications. (C) 2010 The Japan Society of Applied Physics

We developed a patterning technique for nerve cells that uses polytetrafluoroethylene (PTFE) and poly-D-lysine (PDL). The PDL layer on the PTFE substrate acted as a buffer for nerve cell adhesion, while Ar ion-irradiated areas on PTFE were used for separation of nerve cells. This structure was then used as a scaffold. A matrix circuit of nerve cells with dendrites or axons was subsequently observed on the scaffold after a week of cell culture. The Ar ion-irradiated area exhibited graphite or amorphous carbon, and PDL was detached from carbon grains by mechanical stress during cell culture. A possible explanation for the adhesion between PDL and PTFE is the van der Waals force. The stress between PDL/PTFE was reduced by the flexibility of PDL gel, which prevented separation of PDL from PTFE.

Background: Although many Japanese older adults spend more than an hour each day walking for exercise, the intensity is often lower than the minimum level associated with various health benefits. The purpose of this study was to evaluate the efficacy of a lifestyle physical activity intervention on improving quantity and quality of daily physical activity (DPA) as well as cardiorespiratory endurance in community-dwelling older women. Methods: 68 women (60-78 yr of age) were randomly assigned to either a lifestyle physical activity intervention group (LIFE) or control group. During the 12-wk intervention, feedback based on accelerometer DPA data (number of daily steps (STEPS) and time spent performing daily moderate intensity physical activity (MPA) was provided to each participant in LIFE every two weeks. Cardiorespiratory endurance was evaluated using the 12-Minute Walk Test (12-MW). Results: Following the 12-wk intervention, significant group interactions were observed for STEPS, MPA, and cardiorespiratory endurance. LIFE increased STEPS by 16%, MPA by 53%, and the distance walked during the 12-MW by 10%. Conclusions: Promotion of DPA using accelerometers can significantly improve quantity and quality of daily physical activity as well as cardiorespiratory endurance in older women.

Although many Japanese older adults spend more than an hour each day walking for exercise, the intensity is often lower than the minimum level associated with various health benefits. The purpose of this study was to evaluate the efficacy of a lifestyle physical activity intervention on improving quantity and quality of daily physical activity (DPA) as well as cardiorespiratory endurance in community-dwelling older women. Methods: 68 women (60-78 yr of age) were randomly assigned to either a lifestyle physical activity intervention group (LIFE) or control group. During the 12-wk intervention, feedback based on accelerometer DPA data (number of daily steps (STEPS) and time spent performing daily moderate intensity physical activity (MPA) was provided to each participant in LIFE every two weeks. Cardiorespiratory endurance was evaluated using the 12-Minute Walk Test (12- MW). Results: Following the 12-wk intervention, significant group interactions were observed for STEPS, MPA, and cardiorespira- tory endurance. LIFE increased STEPS by 16%, MPA by 53%, and the distance walked during the 12-MW by 10%. Conclusions: Promotion of DPA using accelerometers can significantly improve quantity and quality of daily physical activity as well as cardiorespiratory endurance in older women. © 2009 Human Kinetics, Inc.

Hydroxyapatite (HAp) is one of the most widely used materials for tissue culture scaffolding in regenerative medicine. To apply HAp as a suitable material for tissue culture scaffolding, we have developed freestanding HAp membranes that can be directly transplanted "as is" into a diseased site after tissue culturing. These freestanding HAp membranes are highly biocompatible, provide early cell proliferation and differentiation, and their flexibility allows some degree of configuration to the target site. This tissue culture scaffold is ideal from the standpoint of harvesting tissue and directly transplanting it to the diseased site. (C) 2008 The Japan Society of Applied Physics.

The fixation between a beads-type porous-surfaced dental implant and a surrounding bone is dependent on 3-dimensional anchoring effect which new bones develop into a porous structure. The speed of a bone ingrowth into the porous structure and the good fixation to bone is strongly related to biocompatibility of the implant. To impart a functional fixation by biointegration to the implant, in this study, a pulsed laser deposition (PLD) technique was used to form 300 nm thick hydroxyapatite (HA) film even on the depths of the porous structure. Through X-ray diffraction (XRD) and energy dispersive X-ray spectrometry (EDX) analysis, it was found that HA was crystallized and was deposited on the depths of interconnecting pores of complicated shape. The implants were placed into posterior regions of completely edentulous mandible of a canine. The bone ingrowth condition was scanned by CT scanner. In three weeks after operation, the bone ingrowth speed in the HA-deposited implant was increased as compared with the non-HA-deposited one. In five weeks after operation, no particular differences on the bone ingrowth between the HA-deposited and non-HA-deposited implants were found. HA thin film deposition on a porous-suerfaced implant was effective in the improvement of functional bone fixation.

In the current studies, we deposited ultra-thin hydroxyapatite films on a pure titanium substrate by pulsed laser deposition, and we examined the effects of these surfaces on rat bone marrow (RBM) cells. This method allowed deposition of 500-, 2,000-, and 5,000-angstrom-thick hydroxyapatite films. X-ray diffraction showed that the amorphous films recrystallized to a hydroxyapatite crystal structure after annealing. The proliferation of RBM cells was unaffected by the hydroxyapatite films, but osteocalsin and alkaline phosphatase mRNA and protein levels were elevated in cells grown on 2,000- and 5,000-angstrom-thick films. These results indicate that ultra-thin hydroxyapatite films generated by pulsed laser deposition are better at promoting osteogenesis than pure titanium surfaces.

We developed a real-time measurement system for quantities of movement using hydraulic resistance exercise (HRE) machine-based circuit training that is a promising method for health promotion of aged people. Muscular strength and displacement of motion are measured as fundamental quantities with hydraulic pressure gauges that are connected to the hydraulic cylinders of HRE machine. The time series data of the fundamental quantities are transferred to the computer, by using them, the velocities of motion, the angles of bend, the muscle powers and total energy consumption are calculated and displayed by graphical representation on the monitor. Batch processing by single computer was performed to all resistance machines in circuit training. This system makes possible to accumulate the scientific proofs steadily for the hydraulic resistance exercise.

In the current studies, we deposited ultra-thin hydroxyapatite films on a pure titanium substrate by pulsed laser deposition, and we examined the effects of these surfaces on rat bone marrow (RBM) cells. This method allowed deposition of 500-, 2000-, and 5000-angstrom-thick hydroxyapatite films. X-ray diffraction showed that the amorphous films recrystallized to a hydroxyapatite crystal structure after annealing. The proliferation of RBM cells was unaffected by the hydroxyapatite films, but osteocalsin and alkaline phosphatase mRNA and protein levels were elevated in cells grown on 2000- and 5000-angstrom-thick films. These results indicate that ultra-thin hydroxyapatite films generated by pulsed laser deposition are better at promoting osteogenesis than pure titanium surfaces.

To impart good cell adhesion to poly(vinyl alcohol) hydrogel (PVA-H) as an artificial articular cartilage, hydroxyapatite thin film 300 nm thick was deposited by a pulsed laser deposition technique on PVA-H, which has virtually no cell adhesion. A cell culture method was used to study the effect of hydroxyapatite deposition on PVA-H upon cell adhesion among mouse fibroblasts. The cell adhesion of water content 33% PVA-H coated with the amorphous hydroxyapatite film showed a maximum as high as that of commonly used tissue culture dishes. This technique was also effective for improving cell adhesion, even on a higher water content (53%) PVA-H. This is a novel technique to improve the biocompatibility and attachment of PVA-H and with the underlying bone and natural cartilage. (C) 2006 Elsevier B.V. All rights reserved.

To impart good cell adhesion to poly(vinyl alcohol) hydrogel (PVA-H) as an artificial articular cartilage, hydroxyapatite thin film 300 nm thick was deposited by a pulsed laser deposition technique on PVA-H, which has virtually no cell adhesion. A cell culture method was used to study the effect of hydroxyapatite deposition on PVA-H upon cell adhesion among mouse fibroblasts. The cell adhesion of water content 33% PVA-H coated with the amorphous hydroxyapatite film showed a maximum as high as that of commonly used tissue culture dishes. This technique was also effective for improving cell adhesion, even on a higher water content (53%) PVA-H. This is a novel technique to improve the biocompatibility and attachment of PVA-H and with the underlying bone and natural cartilage. (C) 2006 Elsevier B.V. All rights reserved.

To improve osteoblasts attachment to a porous implant such as artificial tooth root, plasma spray coating of hydroxyapatite (HA) has been attempted applying. However, plasma sprayed HA powders plugged up a way in holes of the porous structure which is important way of bone growth. To solve this problem, in this experiment, HA thin film 300nm thick was deposited by pulsed laser deposition (PLD) technique on the tooth root. HA thin film was reached easily to the depth of the porous structure. In 3 weeks after operation, the bone in-growth speed in HA-deposited tooth root was increased as compared with non HA-deposited one. In 5 weeks after operation, no particular difference between HA-deposited and non HA-deposited tooth roots was found. HA thin film deposition on a porous implant was effective in the improvement of osteoblast attachment.

Biological molecular adsorption on crystal hydroxyapatite (HAp) and amorphous Ca10(PO4)6(OH)2 was investigated using quartz crystal microbalance (QCM) method. The pulsed laser ablation (PLA) was applied to coat both kind films for QCM sensors. A crystal HAp sensor was prepared with thermal treatment during the fabrication process. An amorphous Ca10(PO4)6(OH)2 sensor was prepared without any thermal treatment. Not only crystal HAp but amorphous Ca10(PO4)6(OH)2 showed good adsorptive feature compared with conventional QCM on the market. The result showed that a low temperature deposition of HAp is adaptable to polymer-based materials for medical purposes.

Biological molecular adsorption on crystal hydroxyapatite (HAp) and amorphous Ca10(PO4)6(OH)2 was investigated using quartz crystal microbalance (QCM) method. The pulsed laser ablation (PLA) was applied to coat both kind films for QCM sensors. A crystal HAp sensor was prepared with thermal treatment during the fabrication process. An amorphous Ca10(PO4)6(OH)2 sensor was prepared without any thermal treatment. Not only crystal HAp but amorphous Ca10(PO4)6(OH)2 showed good adsorptive feature compared with conventional QCM on the market. The result showed that a low temperature deposition of HAp is adaptable to polymer-based materials for medical purposes.

A coplanar type lumped-element 6-pole microwave Chebyshev bandpass filter (BPF) of center frequency (f(0)) 2.0 GHz and fractional bandwidth (FBW) 1.0% was designed. For the design method, theory of direct coupled resonator filters using K-inverters was employed. Coplanar type lumped-element BPFs are composed of a meander-line L and interdigital C elements. The frequency response was simulated and analyzed using an electromagnetic field simulator (Sonnet-EM). Further, the changes in fo and FBW of the BPF were also realized by the mechanical tuning method.

A coplanar type lumped-element 6-pole microwave Chebyshev bandpass filter (BPF) of center frequency (f(0)) 2.0 GHz and fractional bandwidth (FBW) 1.0% was designed. For the design method, theory of direct coupled resonator filters using K-inverters was employed. Coplanar type lumped-element BPFs are composed of a meander-line L and interdigital C elements. The frequency response was simulated and analyzed using an electromagnetic field simulator (Sonnet-EM). Further, the changes in fo and FBW of the BPF were also realized by the mechanical tuning method.

The tunable filter has variable center frequency (f(o)) and variable bandwidth (BW) that can be adapted to software defined radio. In our mechanical tunable filter, capacitance of each element is changed by motion of dielectric plate that is located above the capacitive elements. The dielectric plates are moved by piezoelectric bimorph actuators. Tuning test of the fo in a cryocooler is performed using an actual superconducting filter fabricated with YBa2Cu3Oy thin film deposited on an MgO (100) substrate. Taking into account of the effective change of parallel capacitance to ground plane by movement of dielectric plates above the element, we choose the coplanar wave guide type filter that has the ground plane on top side of the substrate. Suitable design of the mechanically tunable superconducting lumped element filter is discussed.

Protein adsorption on hydroxyapatite (HAP) thin film was investigated before and after patterning. Hydroxyapatite thin film 100 nm thick was deposited by pulsed laser deposition. The film was patterned by photolithography and wet etching with HCl solution. Proteins (phospholyrase b, bovine serum albumin, and others) labeled with fluorescein isothiocyanate (FITC) were used as the reagent. After the HAP film was soaked in the reagent and washed with pure water, a conspicuous contrast in FITC was observed between the HAP pattern and the glass substrate (or photoresist). This behavior showed that the biocompatibility of the HAP thin film was not influenced by the patterning process. Our technique for HAP thin film is adaptable for applications involving biosensors as electronic devices and scaffolds for tissue culture.

Protein adsorption on hydroxyapatite (HAP) thin film was investigated before and after patterning. Hydroxyapatite thin film 100 nm thick was deposited by pulsed laser deposition. The film was patterned by photolithography and wet etching with HCl solution. Proteins (phospholyrase b, bovine serum albumin, and others) labeled with fluorescein isothiocyanate (FITC) were used as the reagent. After the HAP film was soaked in the reagent and washed with pure water, a conspicuous contrast in FITC was observed between the HAP pattern and the glass substrate (or photoresist). This behavior showed that the biocompatibility of the HAP thin film was not influenced by the patterning process. Our technique for HAP thin film is adaptable for applications involving biosensors as electronic devices and scaffolds for tissue culture.

An error in surface resistance (R-s) originating from the dielectric loss (tan delta) of the parallel plate dielectric resonator using the two-resonators method is investigated. In the two-resonators method, the error in R-s(DeltaR(s)) due to the difference in tan delta(Delta tan delta) between the TE011 and TE01n mode rods is examined, considering the actual scattering of values of tan delta among sapphire rods. Taking this scattering into account, the projected value of DeltaR(s) cannot be disregarded for general R-s values (about 0.1 mOmega) of HTS films. As a comparative simulation, the case of a single resonator was also considered where the tan delta is neglected in the estimate of R-s. Due to the uncertainty and complexity in the two-resonators method, this method is not so superior to the single-rod resonator measurement by neglecting tan 6 at higher resonance frequency. (C) 2004 Elsevier B.V. All rights reserved.

The growth and characterization of a BaZrO3 buffer layer for controlling the in-plane orientation of YBa2Cu3O7-δ films grown on MgO substrates is described. BaZrO3 buffer layers and YBa2Cu3O7-δ films are grown by pulsed laser deposition. 45° grain boundaries typically exist in YBa2Cu3O7-δ films grown on MgO(001) substrates; these are fatal defects for microwave device applications and are eliminated using the BaZrO3 buffer layer. The preferred orientation and in-plane orientation with respect to the MgO substrates are estimated for MgO lattice-matched BaZrO3 buffer layers grown on MgO substrates. YBa2Cu3O7-δ films grown at an optimum growth temperature of 710°C on BaZrO3 buffer layers on MgO(001) substrates show a lower surface resistance (RS) than those on MgO(001) substrates without BaZrO3 buffer layers.

Epitaxial thin films of a Tl(Ba, Sr)(2)Ca2Cu3Oy (Tl-1223) superconductor with a thickness of 5000 Angstrom were grown on a moderate dielectric constant (epsilon = 23.8) substrate (LaAlO3)(0.3) (Sr2AlTaO6)(0.7) (LSAT) in order to study the miniaturization of a superconducting thin film microwave filter. For the annealing conditions followed in this work, we observed two kinds of surface morphology: both of them have a large plate-like morphology with pits but they differ from each other by the presence of needle shaped (a-axis-oriented) grains on top of the plate-like surface. The superconducting transition temperature (T-c) and critical current density (J(c)) for both kinds of films (with and without needles) are about 108 K and similar to0.8 MA cm(-2) at 90 K, respectively. However, the values of the temperature dependence of the microwave surface resistance (R-s) of the films with needles are about one order higher than those for the films without needles, due to the absorption of microwaves by a-axis-oriented needles. The value of R-s for the films without needles at 90 K and 10 GHz is 507 muOmega, which satisfies the requirement for microwave device applications with high performance.

This paper reports the results the application of sapphire rod trimming to improve HTS filter properties. First, we examined the optimum position of the sapphire rod above the hairpin filter to shift the resonance frequency. The resonance frequency could be changed about 20 MHz, a value which is sufficient for filter trimming. Next, we examined sapphire rod trimming for a 5-resonator hairpin filter. We found that sapphire rod trimming is a very useful technique for improving filter properties; for example, reducing the ripple and increasing the steepness of the filter properties. We also discuss improving sapphire rod trimming using an equivalent circuit model. The improvement and sapphire rod position could be explained by the equivalent circuit model.

The parallel plate dielectric resonator was applied to surface resistance (R-s) measurement of high temperature superconducting films with small area for the purpose of material research in early stage. Using 38 GHz resonance of TE013 mode, available measurement area in the film was diameter of 9 mm. From the theoretical calculation, the measurement at higher frequency had an advantage of less error in R-s that is caused by dielectric loss tangent (tan 6). The effect of dielectric loss is negligible at 38 GHz even using a sapphire with order of 10(-7) of tan delta. In lower R-s region, R-s values of YBa2Cu3Oy that were measured at 38 GHz agreed well with that of standard measurement method at 22 GHz. However the difference of R, between two methods became larger with increase of R-s. It is owing to poor signal to noise ratio at higher frequency. (C) 2003 Elsevier B.V. All rights reserved.

We have examined in-plane orientation Of CeO2 buffer layers on c-plane and tilt-c-plane sapphire substrates. The tilt angles are 5degrees, 10degrees and 15degrees, which are defined as the angles between the c-plane and the surface planes of the sapphire substrates (called 5degrees, 10degrees, 15degrees tilt-c-plane substrates). The films were prepared by inductively coupled plasma sputtering. The in-plane orientation of the films was measured using X-ray phi-scan. phi-scan peaks of films fabricated on c-plane substrates appeared every npi/6 or npi/12 (n: integer), showing 12-fold or 24-fold symmetry. The in-plane orientation is influenced by the hexagonal symmetry of the sapphire c-plane. The degree of film orientation depends on the substrate temperature during preparation. On the other hand, we found weak 4-fold symmetry for films fabricated on 10degrees and 15degrees. tilt-c-plane substrates. This suggests that we can obtain CeO2 films with perfect 4-fold symmetry on tilt-c-plane sapphire substrates. (C) 2003 Elsevier B.V. All rights reserved.

We have examined the relationship between the surface resistance and the depairing current density of superconductors. From the two-fluid model and the relationship between the depairing current density and the thermodynamic critical field, we can show that the surface resistance is in inverse proportion to the depairing current density. We also experimentally examined the correlation between the surface resistance and the critical current density of YBCO thin films, and found that the surface resistance is in inverse proportion to the critical current density. The results mean that our theoretical analysis is suitable for predicting the correlation between the surface resistance and the critical current density.

Epitaxial Tl2Ba2CaCu2Oy and Tl(Ba,Sr)(2)Ca-2 Cu3Oy thin films have been prepared on CeO2 buffered sapphire substrate by an ex situ process with high reproducibility. Microstructure analysis of the surface of the TI-2212 films showed well connected and smaller sized grains of 1 mum or less. In the case of TI-1223 film, plate-like crystals with pits and pin holes could be observed. The superconducting critical temperatures of both films are around 96 K. Critical current density measured by ac susceptibility technique is as high as 1 MA/cm(2) at 77 K. The microwave surface resistance of these films was measured over a wide range of temperatures by a HTS-sapphire-HTS resonator method at 38 GHz on films with area 10 mm x 10 mm. The temperature dependence of surface resistance of TI-2212 film follows very closely to that of the best YBCO films on MgO substrate, whereas the TI-1223 exhibits slightly higher values resulting from an inferior surface morphology.

We observed vortices with a modified Bitter method by evaporating nickel as the medium of decoration, in film and QMG (which are made with the quench-and-melt-growth method) YBa2Cu3O7-delta (YBCO) samples. The temperature range of observation was from 25 K to 90 K, and the external magnetic field was 2 mT. Consequently, we found that the vortex structures of these samples were stable from 25 K to near the critical temperature (similar to90 K). The density of vortex was almost three times larger than that estimated from the external magnetic field. This suggests that the vortex motion may be hopping during nickel evaporation.

A simple method, fishing high-T-c superconductor thin films out of a liquid nitrogen bath by a permanent magnet (field > H-c1), due to the effect of high flux pinning, has been suggested to identify films that have high critical current density (J(c) > 10(6) A cm(-2) at 77 K) and thus a low microwave surface resistance (R-s). We have demonstrated that a Nd-Fe-B magnet, having a maximum field of similar to0.5 T, could fish out TI-1223 superconducting thin films on LSAT substrate with a thickness of similar to5000 Angstrom having J(c) > 1 MA cm(-2) (at 77 K) whereas it could not fish out other films with J(c) < 0.1 MA cm(-2) at 77 K. The fished out films exhibit R-s values 237-245 mum at 77 K and 10 GHz, which is lower than that (R-s = 317 mum) of the commercially available YBCO film at the same temperature and frequency. On the other hand, the non-fishable films show very high R-s values. This method is a very simple tool to test for high J(c) and good microwave properties of large area superconducting films which would otherwise require a special and expensive tool.

Tl2Ba2CaCu2Oy (Tl-2212) and Tl(Ba,Sr)(2)Ca2Cu3Oy (Tl-1223) superconductor thin films have been prepared on CeO2 buffered sapphire substrate by an ex situ process namely, amorphous phase epitaxy (APE) method. In the case of Tl-1223, an amorphous layer of TlSr2CaCu2Oy (TlSr-1212) was deposited on top Of CeO2 layer to avoid chemical reaction between Tl-1223, containing Ba, and CeO2 layers. All films are epitaxial with smooth surface and excellent crystallinity. Superconducting transition temperatures (T-c) of Tl-2212 and 1223 are around 95 and 104 K, respectively. Critical current density (J(c)) at 77 K measured on 5 x 5 mm. films by inductive technique is as high as 2 MA/cm(2). Surface resistance R-s of Tl-2212 films measured by a dielectric resonator technique at 38 GHz is comparable to the best YBCO films. (C) 2003 Elsevier Science B.V. All rights reserved.

Buffer layer materials for growing YBa₂Cu₃O_7−δ thin films on MgO substrates are examined from the viewpoint of YBa₂Cu₃O_7−δ thin-film crystallinity. The buffer layers were grown using an excimer laser. Crystallinity of the buffer layers grown on MgO substrates and the YBa₂Cu₃O_7−δ thin films on the buffer layers were evaluated by X-ray diffraction, X-ray rocking curves and X-ray φ-scan methods. One of key points to obtain YBa₂Cu₃O_7−δ thin films of the highest quality on the MgO substrates is the usage of BaZrO₃ buffer layers that are lattice matched to the MgO substrates. However, every buffer layer examined here showed the result of high-quality YBa₂Cu₃O_7−δ thin films with a T_c of around 89 K and low surface resistance.

To design superconducting microwave receivers, the surface resistance of the superconducting thin film must be considered. Therefore, a. highly accurate technique for measuring the surface resistance of superconducting thin films should be established. In this paper, we propose a probe-coupled microstrip line resonator as a technique for measuring the surface resistance of superconducting thin films. In the resonator technique, the surface resistance is calculated from Q(u), the unloaded Q, of the resonator. Since the microstrip line resonator searches for an accurate surface resistance of the superconducting thin film, establishing a technique that accurately determines the Q(u) of the resonator is crucial. We measure the Q(u) values of resonators fabricated from metal and superconducting thin film by a probe-coupled microstrip line resonator and describe the accuracy of Q(u) measurement by the probe-coupled micro-strip line resonator and the repeatability of the surface resistance measurement of a superconducting thin film. (C) 2003 Wiley Periodicals, Inc.

A scanning mapping technique of surface resistance (R-s) using the sapphire dielectric resonator was developed and demonstrated for a 3-inch-diameter YBa2Cu3Oy film. The area of the 3-inch film was divided by 5 x 5 nun grid for scan, resulting in 101 measurement points. Values of R, in the film varied from 2.9 to 3.8 mOmega at 22 GHz and 77 K. The distribution of R-s corresponded to that of the critical current density. Sampling of quality factors at each point was performed using non-contact measurement between film and sapphire. Since the airtight chamber was filled with dry N-2 gas to avoid film degradation by frost and water during the warming process, perfect non-destructive measurement is realized. Fluctuation of distance between the surface of film and dielectric rod was monitored by resonance frequency. Errors in R-s caused by the fluctuation were calculated within 0.01 mOmega. Furthermore, the system could detect a small (0.3 mm x 0.5 nun) scratch defect as well as the gradient of film thickness on Ag film. This technique is effective for inspection of large-area high temperature superconducting films for microwave applications. (C) 2002 Elsevier Science B.V. All rights reserved.

We have examined vortex distribution of YBa2Cu3O7-delta (YBCO, Y-123) films and YBCO-QMG samples. The vortices were observed by the Bitter method using the decoration of the fine magnetic particles. Observation of vortex distribution was done in the temperature range between 25 and 90 K in the magnetic field range between 0 and 10 mT. We found that vortices of YBCO films and YBCO-QMG samples did not move at 25 K and moved slightly at 75 K, and the interface of the Y2BaCuO5 (Y-211) and Y-123 phases of the YBCO-QMG sample works as pinning center. (C) 2002 Elsevier Science B.V. All rights reserved.

A grain size control technology will be described. YBa2Cu3O7-delta thin films are grown by a pulsed laser deposition method in 400 mTorr oxygen atmosphere. The films are grown by a self-template method with various self-template growth temperatures. However the temperature of the main YBa2Cu3O7-delta layer was fixed. Grain size of YBa2Cu3O7-delta thin films on MgO substrates are observed by atomic force microscope. Mean diameter of grains are calculated by the number of grains in scanned area of 1 x 1 mum(2). The mean diameters are 2.49 x 10(2), 2.89 x 10(2), 4.047 x 10(2) and 4.192 x 10(2) nm for films with an initial layer growth temperature of 670, 690, 714 and 730 degreesC, respectively. Grain size is found to depend on the initial growth stage of the YBa2Cu3O7-delta thin film growth. These grain sizes have a strong relationship with the inverse of substrate temperature indicating thermally excited migration of YBa2Cu3O7-delta nuclei. It is also clarified that migration length of YBa2Cu3O7-sigma nucleus is longer on an YBa2Cu3O7-delta films than on MgO substrates. (C) 2002 Elsevier Science B.V. All rights reserved.

We investigated the dielectric loss tangent (tan delta) of sapphire single crystals produced by edge-defined film-fed growth (EFG) method using a dielectric resonator with YBa2Cu3Oy (YBCO) films. Surface resistance (R-s) of the YBCO film was low enough to obtain high resolution of tan 6 measurement. For comparison, tan delta of the sapphire prepared by the Czochralsky (Cz) method was also evaluated. Measurements of 14 sapphire rods showed that EFG sapphire tends to have lower tan delta than Cz sapphire, while defects in Cz crystal were 1/14-1/2 less than that in EFG crystal. It means that the number of defects does not influence tan delta, if the density of defects is within the order of 10(4)/cm(2). In most EFG sapphire the value of tan 6 at 30 K was estimated to be < 1.0 x 10(-7). It is usable for R-s measurement of high critical temperature superconducting materials. (C) 2002 Elsevier Science B.V. All rights reserved.

We have examined the correlation between the critical current density (J(c)) and the surface resistance (R-s) of an YBa2Cu3O7-delta (YBCO) thin film. YBCO films were prepared in an inductively coupled plasma sputtering system on MgO and BSO/MgO substrates. BaSnO3 (BSO) was used as a buffer material for the MgO substrates. J(c) was determined by magnetic measurements, and R-s was measured using a sapphire rod resonator method, The correlation of critical current and surface resistance has been reported previously, however. there is few researches in which a systematic correlation of R-s and J(c) using the same sample has been done. To begin with, we measured R-s by the dielectric resonator method, and next, J(c) was measured using the magnetic field method, As a result, it was proven that there was a strong correlation between R-s and J(c). We found that the relationship between J(c) and R-s (at 22 GHz) could be expressed by the following equation, R-s = 2.0 x 10(7) J(c)(-1), where the unit of R-s is the ohm, and the unit of J(c) is A/m(2). It was found that the relation was applicable in a wide temperature range under T,. The value of the surface resistance can be estimated. if an accurate critical current is obtained. (C) 2002 Elsevier Science B.V. All rights reserved.

Dual mode devices based on high temperature superconducting films represent an interesting class for telecommunication applications since they combine a miniaturized size with a good power handling. Here we report on a novel compact antenna obtained by crossing a square patch with two or more slots. The proposed design has an antenna size reduction of about 40% as compared to the conventional square patch microstrip antennas. Single patch antenna both with linear (LP) and circular (CP) polarization operating in the X-band have been designed and tested at prototype level. They are realized by using double sided (YBa2Cu3O7-x) YBCO and TI2Ba2Ca1Cu2O8 (TI-2212) superconducting films grown on MgO substrates and tested with a portable cryocooler. They showed at T = 77 K a return loss <25 dB and a power handling of 23 dBm. Exemplary 16 elements arrays LP antennas operating in the X band have been also realized by using YBCO film grown on 2" diameter MgO substrate. (C) 2002 Elsevier Science B.V. All rights reserved.

The use of high-temperature superconducting films for the fabrication of antennas allows us to realize radiating structures that are small in size and have a very high efficiency. In this paper, we investigate the properties of a novel compact antenna obtained by crossing a square patch with diagonal and transverse slots. Single patch antennas, with both linear and circular polarization operating in the X-band, with a size reduction of about 40% as compared to conventional square patches, have been designed and tested at prototype level. They have been realized by using double-sided YBa2Cu3O7-x,(YBCO) and Tl2Ba2Ca1Cu2O8(Tl-2212) superconducting films grown on MgO substrates and have been measured using a portable cryocooler. At T = 77 K, the experimental scattering parameter, S11, agrees well with simulations, showing a power handling of 23 dBm for YBCO devices. The miniaturized patch antenna investigated has allowed us to realize a 4 x 4 array of linear polarization antennas at 11.5 GHz, using a YBCO film grown on a MgO substrate with a 2" diameter, by considering a reduced interspace (more than 20%) between the elements. The far-field pattern and the 16-array gain are in good agreement with the simulated results.

超伝導マイクロ波受動デバイスを設計するためには, 超伝導薄膜の表面抵抗を考慮する必要がある.このため, 超伝導薄膜の表面抵抗の高精度測定法の確立が望まれている.本論文では, 超伝導薄膜の表面抵抗の測定法としてプローブ結合型マイクロストリップ線路共振器法を提案する.共振器法では, 表面抵抗は共振器の無負荷Q, Quから計算される.したがって, マイクロストリップ線路共振器法により超伝導薄膜の表面抵抗を正確に求めるためには, 共振器のQuを高精度測定する技術の確立が重要となる.プローブ結合型マイクロストリップ線路共振器法により金属と超伝導薄膜から作製した共振器のQu測定を行い, プローブ結合型マイクロストリップ線路共振器法によるQu測定の測定精度と, 超伝導薄膜の表面抵抗測定の再現性について述べる.

Lanthanide (Ln) atom in Ln2CuO4 buffer layer dependence of c-axis in-plane aligned a-axis oriented YBa2Cu3O7-δ (YBCO) thin film growth is discussed and preferred orientation growth model of a bc-plane matched growth model is proposed. The c-axis in-plane aligned a-axis oriented YBCO thin films are very attractive from both the researches on the origin of high Tc superconductors and microelectronics device applications. However the c-axis in-plane aligned a-axis oriented films are difficult to grow. We have been proposing Ln2CuO4 buffer layers for the c-axis in-plane aligned a-axis oriented YBCO thin film growth. We have examined various Ln atoms in Ln2CuO4 buffer layers for the growth of YBCO thin films by pulsed laser deposition. From a lattice matching point of view, a Tb2CuO4 buffer layer is the best one for the c-axis in-plane aligned a-axis oriented YBCO thin films. However the result shows that the Nd2CuO4 and Tb2CuO4 buffer layer causes YBCO thin films with c-axis oriented portion about 35% and 32%, by X-ray diffraction peaks, which is much larger than those on Gd2CuO4 buffer layers (7.4%). The most promising Ln atom in Ln2CuO4 buffer layers for the growth of the c-axis in-plane aligned a-axis oriented YBCO thin films so far is Gd2CuO4 buffer layers or Eu2CuO4 buffer layers. © 2001 Elsevier Science B.V. All rights reserved.

High-temperature superconducting microwave filters were designed for the W-CDMA communication system. Frequency responses of the filters were calculated by the electromagnetic simulator "Sonnet-em". A cross-coupled 8-pole microstrip line filter shows 1.949 GHz of center frequency and 1.04% of transmission fractional bandwidth on the LaAlO3, and 1.950 GHz of center frequency and 1.02% of transmission fractional bandwidth on the Al2O3. © 2001 Elsevier Science B.V. All rights reserved.

We have observed vortices of the high-temperature superconductor using the Bitter technique. Hopping movement of vortices of Y-123 and Bi-2212 single crystal was observed in the temperature range of 50-90 K (T-c) by the thermal energy. We estimated pinning potential by migration length, The pinning potential, we have also observed the vortex pattern of Y-123 QMG sample including Y-211 phase. We found that vortex existed in the grain boundary of Y-211 and Y-123 phase. (C) 2001 Elsevier Science B.V. All rights reserved.

The effect of lattice matching between YBa2Cu3O7-δ (YBCO) films and buffer layers as well as between buffer layers and MgO substrates have been discussed from viewpoints of crystalline, critical temperature and surface resistance of YBCO films. SrSnO3(SSO) as well as BaSnO3 (BSO) were used as buffer materials. SSO has closer lattice constant to YBCO than BSO. YBCO films were grown on these materials at the optimal growth temperature by pulse laser deposition. The FWHM of φ-scan (102) plane of YBCO films on SSO buffer layers was smaller than that of YBCO films on BSO buffer layers. However the values of FWHM of 005 rocking-curve of YBCO films on BSO buffer layer were smaller than that of YBCO films on SSO buffer layer. The difference of surface resistance between YBCO film on BSO buffer layer and YBCO film on SSO buffer layer was very small indicating superconducting properties are not mainly governed by lattice mismatch at this region. We obtained the same values for c-axis length and critical temperature in YBCO films on these materials.

We have examined the relationship between in-plane orientation, grain size, fluctuation of grain axis and surface resistance of YBa2Cu3O7-δ (YBCO) films. The surface resistance of YBCO films with a mixture of (100) and (110) in-plane grains was larger than that of the films with perfect in-plane orientation. The behavior of surface resistance could be explained by the degree of grain boundaries of (100) and (110) in-plane orientation. The surface resistance of YBCO films was proportion to the fluctuation of grain axis. It was also proven that surface resistance of high-temperature superconductors is affected by the critical current.

We have developed a new surface resistance (R-s) measurement technique of high-temperature superconductors using a probe coupling microstrip line resonator. In this technique, the probe coupling method is used to measure the R-s of superconductors without attaching any contacts to the superconductors, This paper reports the measurement process of the R-s of a superconducting fine-wire using this technique. The quality Factors of the copper wires, gold fine-wire and the Bi-Sr-Ca-Cu-O whisker crystal were measured by the probe coupling resonator method. The measurement results revealed that this technique is feasible for the R-s measurement of the superconducting fine-wire.

Two types of miniaturized cooling systems for High-Temperature Superconducting (HTS) antennas were designed and built, In this paper, details of these systems, measured and simulated properties of patch antennas installed in these systems, and results of a seal-off trial for 1 month are reported, Both the systems had portable size and weight and could cool the HTS devices. When a patch antenna with resonant frequency of 4.9 GHz was installed in the Ist cooling system, the radiation pattern of the antenna was strongly focused in the forward direction. This is because the vacuum chamber in which the antenna was packaged influenced the microwaves radiated from the antenna. Due to this effect, the directive gain of the antenna was enhanced by 11.2 dB. In the 2nd system, a seal-off-trial was carried out to investigate the airtight property that is necessary for thermal isolation. The temperature of the sample stage could be kept under the critical temperature of YBCO for 1 month without continuous vacuum pumping. The cooling systems developed in this work are expected to promote the practical use of HTS antennas.

Large-area poised laser deposition (PLD) has reached a state in terms of film quality and reproducibility which makes possible now real market applications of PLD-YBa2Cu3O7-delta (YBCO) thin films on both sides of it-plane sapphire substrates as HTSC devices in satellite and mobile communication systems. Bandpass filters optimized from PLD-YBCO thin films presently fulfill the requirements of the main national companies which are active in future communication techniques. A relatively simple PLD arrangement with fixed laser plume and rotating substrate, with an offset between the laser plume and the center of the substrate is employed to deposit laterally homogeneous 3-inch diameter Ag-doped YBCO thin films. With the experience of more than 1,000 doable-sided 3-inch diam, films a high degree of homogeneity and reproducibility of j(c) and R-s is reached. The extension up to 8-inch substrate diameter will increase the productivity of the flexible PLD technique considerably.

The surface resistance of high-Tc superconducting films at microwave frequencies was carefully measured by the dielectric resonator method using two sapphire rods. The dielectric resonator method is appropriate for the standard measurement of surface resistance at microwave frequencies. In the present work, we focused on asymmetry in coupling and the parasitic coupling effect which cause error in this method and discussed the precision and accuracy of the measurements. Finally, we report on a round robin test in which the observed surface resistances in three institutes gave good agreement. These results were reflected in the working draft of the International Electrotechnical Commission Technical Committee 90 (IEC/TC90). © 2001 Elsevier Science B.V.

Measured results and discussion on vacuum seal-off property of a cooling system for high-temperature superconducting antennas are reported. The cooling system was designed and fabricated and its cryogenic packaging was investigated. Vacuum seal-off tests were performed and high vacuum for thermal isolation could be kept for 25 days. On the cold stage of the system, some kinds of gas, including H2O and CO2, were adsorbed on a cold stage. © 2001 Elsevier Science B.V.

The critical thickness of BaSnO3 (BSO) buffer layer for YBa2Cu3O7-δ (YBCO) thin films on MgO substrate is discussed from viewpoints of the in-plane orientation and critical temperature. Thin films are grown by changing the thickness of BSO buffer layers at optimal growth temperature of YBCO films by pulse laser deposition. We are able to control the in-plane orientation of YBCO films with the BSO buffer layers thicker than 2 nm. This result indicates that BSO buffer layers can control the in-plane orientation of YBCO with a thickness less than the other buffer materials reported so far.

Microstructures of YBa2Cu3O7 (delta) / BaSnO3 superlattice are analyzed by Transmission electron microscopy. YBa2Cu3O7 (delta) / BaSnO3 superlattices are fabricated by a pulsed laser deposition technique with in-situ rotation of target materials. Typical growth conditions of substrate temperature and oxygen pressure are 710 degreesC and 400 mTorr, respectively. A few nm thick BaSnO3 insulating layers and YBa2Cu3O7-delta superconducting layers are sequentially deposited with total thickness of around 150 nm. Crystallographic characteristics of these superlattices are evaluated by x-ray diffractometry (XRD) and transmission electron microscopy (TEM). Several layers of YBa2Cu3O7 (delta) and BaSnO3 are clearly observed by TEM. The observed thickness of one layer of YBa2Cu3O7-delta and that of BaSnO3 films are 12 nm and 6.5 nm, respectively From a high-resolution TEM observation, the strain induced by lattice length difference between YBa2Cu3O7 (delta) and BaSnO3 are released by introducing misfit dislocations in the YBa2Cu3O7 (delta) films not in the BaSnO3 films. A new insulating layer is required with small lattice mismatch to YBa2Cu3O7-delta for avoiding introduction of misfit dislocations.

The elimination of α-axis orientation in YBa2Cu3O7-8 (YBCO) films grown on CeO2-buffered A12O3 for microwave devices was achieved through a two-step deposition process performed at different temperatures. The growth of α-axis-oriented YBCO film was considered to be due to the impediment of the adatom mobility by the surface roughness of the underlying buffer layer. For the initial layer, the deposition was carried out at a high temperature to increase surface mobility. Next, the deposition was performed at a lower temperature as necessary for optimum α-axis-oriented growth. By this method, only a α-axis-oriented film was obtained. The characteristic surface resistance Rs(T) values for this film were significantly lower than those with mixed c-and α-axis orientations. © 2000 Publication Board, Japanese Journal of Applied Physics.

We have examined that how to reduce the surface resistance, Rs of YBCO films, and found that control of the in-plane alignment of the YBCO films was very important to realize that. The in-plane alignment of the YBCO films on MgO substrates could be controlled by the BaSnO3(BSO) buffer layers, and self-template method. We also examined YBCO patch antenna and its compact cooling system. The compact cooling system was easy to keep YBCO patch antennas in the superconducting state.

The electrical resistance of a c-axis-oriented YBa2Cu3O7-δ film is measured at elevated temperatures, under various values of oxygen pressure. The resistance shows a monotonic increase with substrate temperature up to around 450 °C, indicating little oxygen out-diffusion. Above this temperature, the rapid increase of the electrical resistance shows out-diffusion of oxygen from the film. As the temperature is increased, an abrupt drop occurs above a certain temperature (Tm) where the resistance indicates its highest value. Tm has an oxygen pressure dependence, which is similar to the oxygen pressure dependence of the orthorhombic-to-tetragonal transition line in an oxygen pressure-inverse of temperature phase diagram of YBa2Cu3O7-δ. From the observation of surface morphologies, the Tm is thought to be a sort of melting temperature where a partial melting of the YBa2Cu3O7-δ film occurs.

The configuration of the antenna of the dielectric resonator is investigated to measure the exact surface resistance (R-s) of the high temperature superconductor (HTS) thin films over a wide range of temperature. The sapphire dielectric resonator is operated at 22GHz. The loop-terminated semi-rigid cables are used as the antennas. Using a Cu resonator at room temperature, the circumference length of the loop (L), the distance from the dielectric center to the loop center (d), and the height of the loop plane from the substrate surface (h) were changed. It is found that the smaller loop set at a position halfway to the height of the dielectric rod brought the widest region of d in which exact measurements can be carried out. This result was then applied using a HTS resonator. In order to measure exact Q(u) over a wide temperature region from low temperature to the critical temperature, weak coupling rather becomes a disadvantage. The best position of the antenna can be obtained when insertion loss set around -10dB at minimum temperature of the system.

The YBa2Cu3Oy (YBCO) film having low surface resistance (RS) was prepared using an inductive coupled plasma sputtering technique. To increase the low deposition rate, a new self-template method was examined. The YBCO films fabricated on the 21-nm-thick template YBCO layer were c-a ris oriented grain perfectly and successfully grew even at 3 times higher deposition rate. However, the R-s was not low enough, due to the in-plane misaligned grains. Therefore, the BaSnO3 (BSO) buffer was used to obtain perfect in-plane aligned grains. The R-s value of the YBCO/YBCO-template/BSO/MgO film was 0.38 m Omega at 35 K and 1.13 m Omega at 77 K in measurement frequency 22 GHz. The R-s values scaled to 10 GHz were 0.08 m Omega at 35 K and 0.23 m Omega at 77 K, respectively.

YBa2Cu3O7-delta(YBCO)/BaSnO3(BSO) thin films are successfully deposited by laser ablation on both sides of [100] MgO substrate. At first, YBCO/BSO thin films were grown to estimate BSO critical thickness. The critical thickness of BSO for YBCO in-plane orientation is found to be approximately 2nm. Using this condition, double-sided YBCO/BSO films are grown on both sides. In-plane orientation for both sides indicates the absence of impurity phases. The full width at half maximum (FWHM) of the YBCO (005) peak for both sides is similar to 0.50 degrees. The surface resistances in both sides at 22GHz are approximately 1.0 m Omega at 35K.

Effects of cation mixing on the growth of a-axis oriented NdBa2Cu3O7-delta films grown by ArF pulsed laser deposition on LaSrGaO4 (100) substrates with a buffer layer of Gd2CuO4 are investigated by x-ray diffractometry and cross-sectional transmission electron microscopy (TEM). Films are c-axis in-plane aligned a-axis oriented with a few amount of c-axis oriented portion. mixture of a- and c-axis oriented regions were observed in the NdBa2Cu3O7-delta films which are quite different from a-axis oriented YBa2Cu3O7-delta thin films. In the a-axis oriented YBa2Cu3O7-delta thin films, c-axis oriented portion was always observed in the vicinity of the interface between the substrates and the, films. These results indicate that a preferred orientation changing of YBa2Cu3O7-delta films from c-axis to a-axis on lattice mismatched substrates are not originated from mixing of cations of Y and Ba.

We have examined the effect of the loss in the cavity on the measurement accuracy of surface resistance (Rs) of a superconducting thin film using a microstripline resonator. The Rs of a YBCO thin film was measured as a parameter of the height of the cavity's ceiling. The investigation revealed that the loss in the ceiling affected the measurement accuracy of Rs for a comparatively lower ceiling height. However, when the ceiling's height was sufficiently high, the effect was negligible.

We have developed a probe-coupling type microstripline resonator method for accurate measurement of the surface impedance of superconductors. By this improved microstripline resonator method, the surface impedance can be measured without attaching any contacts to the film. This paper reports the accurate and reproducible measurement process of surface impedance using the probe-coupling type microstripline resonator. The surface impedance of a YBCO thin film was measured using this technique. The measured results revealed that this technique may be used for the accurate measurement of surface impedance.

The appearance of 45° grain boundaries in c-axis oriented YBa2Cu3Ox films grown by pulsed laser deposition on MgO (001) substrates is discussed. X-ray φ-scan (in-plane orientation) measurements have revealed that YBa2Cu3Ox films grown at around 700°C have two types of grains with [100]Mgo ∥ [100]YBCO and [110]MgO ∥ [100]YBCO in-plane epitaxial relationships. A plausible growth model is proposed from the viewpoints of lattice matching and ionic adhesive energy. The ratio of 0° and 45° grains is found to be a function of the substrate temperature. By decreasing the substrate temperature, we obtained c-axis oriented YBa2Cu3Ox thin films with only a [100]Mgo ∥ [100]YBCO in-plane epitaxial relation. We have eliminated the 45° grain boundaries which drastically increase the surface resistance of the YBa2Cu3Ox films for microwave applications. ©1999 Publication Board, Japanese Journal of Applied Physics.

All in-plane aligned a-axis oriented YBa2Cu3Ox/Gd2CuO 4/YBa2Cu3Ox superconductor/insulator/superconductor (SIS) junction structures are fabricated by a pulsed laser deposition technique and their microstructures are characterized. An insulating barrier of Gd2CuO4 with an atomic graphoepitaxial relation is selected from a lattice-matching point of view for the b-and c-axes of YBa2Cu3Ox at a deposition temperature of the YBa2Cu3Ox films. Preferred orientations and in-plane alignments of electrodes of YBa2Cu3Ox films and barriers of Gd2CuO4 films are confirmed by X-ray diffraction spectroscopy and an X-ray φ-scan technique. X-ray diffraction measurements revealed that all the YBa2Cu3Ox/Gd2CuO 4/YBa2Cu3Ox films are a-axis oriented. The c-axes of the layers are also in-plane aligned. ©1999 Publication Board, Japanese Journal of Applied Physics.

The surface resistance of superconductors is smaller than that of normal conductors by several orders of magnitude. Hence, a superconducting microwave device has lower loss and higher performance than a normal conducting one. Since the mobile communication systems have become popular and cryocoolers of small size and light weight have been fabricated in recent years, research activity on superconducting microwave devices has been enhanced. In this paper, the design, fabrication, and characterization of a patch antenna using a high-temperature superconducting thin film are reported. It is demonstrated that the superconducting patch antenna has higher gain than a normal conducting one. The temperature dependence of the resonant frequency, the input resistance, and the power handling properties are also discussed. (C) 1999 Scripta Technica.

The complex surface impedance (Z(s)) of a superconductor is comprised of two unequal components, surface resistance (R-s) and surface reactance (X-s). We have investigated the effects of R-s and X-s on the YBa2Cu3O7-x (YBCO) superconducting microstrip antenna properties (resonant frequency, input impedance, and gain) by theoretical analysis and experimentation. The antennas were fabricated from YBCO thin films on (100) MgO single crystal substrate at 11.7 GHz. The investigation of the antenna properties reveals that the X-s of the superconducting thin film mainly influences the antenna resonant frequency (f(r)) and has small influence on the antenna input impedance (R-m). On the other hand, R-s mainly affects the input impedance of the antenna. The antenna gain, and hence the efficiency, is found to be influenced by the film surface resistance. The antennas were characterized in the temperature range of 10-90 K. Possible influences of the substrate dielectric properties (permittivity, epsilon(r) and loss tangent, tan delta) on the antenna properties were also considered in the investigation. (C) 1999 Elsevier Science B.V. All rights reserved.

The surface resistance of superconductors is smaller than that of normal conductors by several orders of magnitude. Hence, a superconducting microwave device has lower loss and higher performance than a normal conducting one. Since the mobile communication systems have become popular and cryocoolers of small size and light weight have been fabricated in recent years, research activity on superconducting microwave devices has been enhanced. In this paper, the design, fabrication, and characterization of a patch antenna using a high-temperature superconducting thin film are reported. It is demonstrated that the superconducting patch antenna has higher gain than a normal conducting one. The temperature dependence of the resonant frequency, the input resistance, and the power handling properties are also discussed. (C) 1999 Scripta Technica.

We have examined the effect of varying the CeO2 buffer layer thickness on the microwave surface resistance R-s and surface morphology of YBCO films deposited by pulsed laser deposition. Above the critical thickness value d(c) of CeO2 at similar to 90 nm, the surface roughness and areal density of outgrowths of the film increased significantly. The YBCO films grown on CeO2 with thickness less than d(c) were completely c-axis oriented and had lower c-axis lengths than those grown on CeO2 with thickness greater than d(c). R-s measured via the sapphire dielectric resonator technique was significantly lower for the YBCO film grown on CeO2 with thickness less than d(c). The increase in the R-s value when the buffer layer thickness is greater than d(c) is considered to be due to the increased surface outgrowths and presence of a-axis domains in the YBCO film. Changes in the microstructure and orientation of the YBCO films were found to be strongly influenced by the underlying CeO2 layer.

45° grain boundaries, which drastically increase surface resistance (RS) in superconducting YBa2Cu3O7-δ films for microwave devices on MgO substrates, are eliminated using a new buffer layer of BaSnO3. BaSnO3 buffer layers and YBa2Cu3O7-δ films are grown by ArF pulsed laser deposition. Epitaxial relationships among BaSnO3, YBa2Cu3O7-δ and MgO are confirmed by x-ray φ-scanning. The RS values of the YBa2Cu3O7-δ films are measured using a dielectric resonator with 22 GHz TE011 mode. The epitaxial YBa2Cu3O7-δ films grown on BaSnO3 buffered MgO substrates show lower RS than YBa2Cu3O7-δ films directly grown on MgO substrates. The BaSnO3 buffer layer which enables YBa2Cu3O7-δ films to grow without 45° grain boundaries at a optimum film growth condition is attractive for microwave applications.

The effect of in-plane 0-45° grain boundaries on surface resistance (R s ) of c-axis YBa 2 Cu 3 O y (YBCO) films on MgO substrates is discussed. Samples that have various densities of 45° rotated grains were prepared using a self-template technique. The R s values at 22 GHz were measured by the dielectric resonator method using a cryocooler. The R s systematically changed corresponding to the amount of 0-45° grain boundaries. Conspicuous feature of the films including 0-45° grain boundaries is a large residual surface resistance. The R s of almost perfectly in-plane aligned YBCO film scaled to 10 GHz were 0.12 mΩ at 20 K and 0.67 mΩ at 77 K on the assumption of tan δ = 0, respectively.

A new BaSnO3 buffer layer is proposed for controlling the in-plane orientation of YBa2Cu3O7-δ films grown on MgO substrates. BaSnO3 buffer layers and YBa2Cu3O7-δ films are grown by pulsed laser deposition. 45° grain boundaries in YBa2Cu3O7-δ films grown on MgO (001) substrates, which are fatal defects for microwave device applications, are eliminated using the BaSnO3 buffer layer. YBa2Cu3O7-δ films grown at an optimum growth temperature of 710°C on BaSnO3 buffer layers on MgO (001) substrates show lower surface resistance (RS) than those on MgO (001) substrates without BaSnO3 buffer layers.

We have investigated the effect of the deposition rate, as a direct function of the laser pulse repetition rate, on the surface morphology of CeO2 films deposited by the pulsed laser deposition (PLD) technique on r-cut Al2O3 (11̄02) substrates. The critical thickness is defined as the thickness before the onset of increased growth of large islands and abrupt increase in surface roughening. Two regimes of growth were found within the investigated range of deposition rate. It is found out that in the high deposition rate-regime (within 2-4 nm/min), the critical thickness is approx. 90 nm, but in the low deposition rate-regime (less than 1 nm/min), the critical thickness is shifted to approx. 40 nm. Films belonging to these two regimes of crystalline growth were found to have characteristically different formations and surface morphologies. As observed through atomic force microscopy (AFM), the surface morphology is composed of longitudinal islands forming a maze-like pattern in the high deposition rate-regime, while the characteristic morphology was composed of rounded islands in the low deposition rate-regime. Significant reduction in the areal density of large islands and characteristically smoother films was achieved using a low deposition rate.

The high-resolution Bitter pattern technique has been used to observe vortex movement of oxide superconductors, Bi2St2CaCu2Oz (BI2212). The Bitter pattern was observed in field-cooled (FC) and zero-field cooled (ZFC) experiments. We also examined vortex movement of the BI2212 single crystal in which transport current was applied parallel to the c plane, and a de magnetic field applied normal to the c plane at the Ni decoration. The Ni decoration pattern was observed using a scanning electron microscope (SEM) and an atomic force microscope ( AFM). Through observation of the Ni decoration pattern, we can identify vortex movement. The vortices moved into the sample on FC experiment, and the direction of vortex movement was approximately normal to the edge of the sample. We also found the vortex movement in a line under application of transport currents. They moved hopping among pinning centers due to Lorentz force. © 1999 IEEE.

The effects of the crystallinity and surface roughness of CeOz buffer on It-plane A1}O3 substrate on the microwave surface resistance (RJ of YBBjCUjO YBCO) thin films are discussed. We estimated Rf from the transmission characteristics of the microstrip line resonator at 25 K and 6.7 GHz. X-ray diffraction (XRD) of 6-26 and -scan showed that CeO, was completely (OOl)-oriented and in-plane aligned crystal Four CeO: samples with different thicknesses were prepared nsing identical conditions except for the deposition time. The dependence of Rf on CeO, thickness was measured in the range from 10 nm to 200 nm. The value of Rt was minimum at CeO2 thickness of 100 nm. The dependence of A( vs CeO2 thickness was similar to that of the amount of a-axis domains against the thickness. The crystallinity of thin CeOj was poor because the lattice was strongly strained by A12O3. This affected the quality of the upper YBCO layer. In contrast, thick CeO2 had excellent crystallinity. However, for the thickness of more than 100 nm a drastic change in surface morphology was observed by atomic force microscopy (AFM). A number of projections appeared on the CeO,surface. These projections act as nucleation centers for the a-axis domains. © 1999 IEEE.

Measured results of power handling capability characteristics of superconducting patch antenna and it's improvement are reported. A direct-fed patch antenna is fabricated by YBa2Cu3Oy, thin film with 50nm thickness. The gain of the antenna does not change with the applied power up to 26.3dBm at 12.3K, but drop of the gain is observed more than 26.5dBm. It is found by electromagnetic analysis that this gain drop occurs due to huge current concentration in the direct-fed patch. However, this current concentration can be reduced using the gap-coupled feed, and breakdown power is expected to be three times larger than that of direct feed. © 1999 IEEE.

超伝導体は通常の金属に比べて数けた小さい表面抵抗を有するため, 超電導体を用いた低損失な高周波デバイスの実現が期待されている.特に近年に見られる移動体通信の急速な普及と, 超伝導デバイスの冷却に用いる冷凍機の小型化技術の進歩に伴い, 超伝導体を用いた高周波デバイスの研究が盛んに行われている.本論文では, 酸化物超伝導薄膜を用いたパッチアンテナの設計・試作・評価について述べる.超伝導パッチアンテナは, 同じ形状の常伝動アンテナに比べて高い利得を有することが明らかとなり, 超伝導アンテナの高効率性を実証した.また, アンテナ特性の温度変化の原因についての考察や, 耐電力特性の測定結果とその向上策, 小型冷凍機を用いた超伝導アンテナの実用化についての検討などについて述べる.

We studied the surface morphology and orientation of CeO2 films grown by pulsed laser ablation (PLA) on r-cut (1 (1) over bar 02) Al2O3 substrates and evaluated the effects of predeposition annealing conditions of Al2O3 and film thickness of CeO2, The annealing of Al2O3 substrates improves the smoothness of the surface and performing this in high vacuum leads to better crystallinity and orientation of deposited CeO2 films compared to those annealed in oxygen. A critical value of the film thickness was found beyond which the surface roughness increases abruptly. Atomic force microscopy (AFM) study showed that the surface of CeO2 films is characterized by a mazelike pattern. Increasing the film thickness leads to the formation of larger islands which cause the increase in the surface roughness of the films. The areal density and height of these islands increased with film thickness.

超伝導体は通常の金属に比べて数けた小さい表面抵抗を有するため, 超電導体を用いた低損失な高周波デバイスの実現が期待されている.特に近年に見られる移動体通信の急速な普及と, 超伝導デバイスの冷却に用いる冷凍機の小型化技術の進歩に伴い, 超伝導体を用いた高周波デバイスの研究が盛んに行われている.本論文では, 酸化物超伝導薄膜を用いたパッチアンテナの設計・試作・評価について述べる.超伝導パッチアンテナは, 同じ形状の常伝動アンテナに比べて高い利得を有することが明らかとなり, 超伝導アンテナの高効率性を実証した.また, アンテナ特性の温度変化の原因についての考察や, 耐電力特性の測定結果とその向上策, 小型冷凍機を用いた超伝導アンテナの実用化についての検討などについて述べる.

We have investigated the performances of several types of vortex flow transistors including nanobridge vortex flow transistors (NBVFTs) based on a parallel array of nanobridges planar Josephson vortex flow transistors (planar JVFTs) based on a parallel array of grain boundary Josephson junctions and new JVFTs with a stacked structure (stacked JVFTs). Considering the integration and the reduction of the L/R time constant the areas of the transistors were restricted to less than 3 5 O-4m2. A NBVFT showed a flux-to-voltage transfer function of 2.6mV/Q which was one order of magnitude larger than that of the other transistors. In contrast the NBVFTs showed a very small current gain due to a large kinetic inductance of a nanobridge while the NBVFT had the smallest area among the three. A planar JVFT with asymmetric geometry was easy to fabricate and showed a current gain of 2.2 at 4.2K. However the planar JVFT requires a large area leading to a long response time other than the internal delay time. A stacked JVFT also showed a current gain of 2.5 at 4.2K. A layered structure yielded a strong coupling between the body of the JVFT and the control line. Due to this strong coupling the response time of the stacked JVFT was considerably improved compared to that of the p lanar JVFT. © 1997 IEEE.

YBa2Cu3Oy (YBCO) superconducting thin films were deposited on MgO single crystals by induction-coil-coupled sputtering. The effects of the induction coil on the qualities of YBCO thin films are examined. Uniformity of film thicknesses below +/-5% was obtained over an area of 40 mm diameter using a 50 mm diameter target by the condition of the substrate-target distance of 90 mm. Even in the area of 60 mm diameter which was wider than that of the target, the uniformity of thickness within +/-17% was obtained. In order to clarify the effects of the induction-coil, we studied the dependence of the critical temperature (T-c) and the full width at half maximum (FWHM) of the films on the applying power of coil. T-c and FWHM showed optimum Values at the applying coil power of 70W. It is confirmed from these results that the induction-coil operated effectively to fabricate high quality films. The epitaxial relations of YBCO films on MgO single crystal substrates were examined by X-ray pole figure measurements. Basically film of YBCO was aligned with the c-axis perpendicular to the substrate surface. The film deposited at the coil power of 70W exhibited well single-oriented grains with the a- or b-axis parallel to the a-axis of MgO. However, films deposited at the applying coil power of 0W contained grains with two different orientations which were rotated by 45 degrees. Scanning electron microscopy (SEM) of the film surface showed the films to consist of a smooth background surface and a distribution of particles. Energy dispersive X-ray analysis (EDAX) measurements showed that the Ba concentration was larger than that of exact stoichiometric composition. Auger electron spectroscopy (AES) revealed that the elements contained in the particles were richer in Ba than in the smooth background surface. The BaCuO2 particles seemed to precipitate on the surface of the film.

YBa2Cu3Oy (YBCO) superconducting thin films were deposited on MgO single crystals by induction-coil-coupled sputtering. The effects of the induction coil on the qualities of YBCO thin films are examined. Uniformity of film thicknesses below +/-5% was obtained over an area of 40 mm diameter using a 50 mm diameter target by the condition of the substrate-target distance of 90 mm. Even in the area of 60 mm diameter which was wider than that of the target, the uniformity of thickness within +/-17% was obtained. In order to clarify the effects of the induction-coil, we studied the dependence of the critical temperature (T-c) and the full width at half maximum (FWHM) of the films on the applying power of coil. T-c and FWHM showed optimum Values at the applying coil power of 70W. It is confirmed from these results that the induction-coil operated effectively to fabricate high quality films. The epitaxial relations of YBCO films on MgO single crystal substrates were examined by X-ray pole figure measurements. Basically film of YBCO was aligned with the c-axis perpendicular to the substrate surface. The film deposited at the coil power of 70W exhibited well single-oriented grains with the a- or b-axis parallel to the a-axis of MgO. However, films deposited at the applying coil power of 0W contained grains with two different orientations which were rotated by 45 degrees. Scanning electron microscopy (SEM) of the film surface showed the films to consist of a smooth background surface and a distribution of particles. Energy dispersive X-ray analysis (EDAX) measurements showed that the Ba concentration was larger than that of exact stoichiometric composition. Auger electron spectroscopy (AES) revealed that the elements contained in the particles were richer in Ba than in the smooth background surface. The BaCuO2 particles seemed to precipitate on the surface of the film.

YBa2Cu3Oy (YBCO) superconducting thin films were deposited on MgO single crystals by induction-coil-coupled sputtering. The effects of the induction coil on the qualities of YBCO thin films are examined. Uniformity of film thicknesses below ±5% was obtained over an area of 40 mm diameter using a 50 mm diameter target by the condition of the substrate-target distance of 90 mm. Even in the area of 60 mm diameter which was wider than that of the target, the uniformity of thickness within ±17% was obtained. In order to clarify the effects of the induction-coil, we studied the dependence of the critical temperature (Tc) and the full width at half maximum (FWHM) of the films on the applying power of coil. Tc and FWHM showed optimum values at the applying coil power of 70W. It is confirmed from these results that the induction-coil operated effectively to fabricate high quality films. The epitaxial relations of YBCO films on MgO single crystal substrates were examined by X-ray pole figure measurements. Basically film of YBCO was aligned with the c-axis perpendicular to the substrate surface. The film deposited at the coil power of 70W exhibited well single-oriented grains with the a- or b-axis parallel to the a-axis of MgO. However, films deposited at the applying coil power of 0W contained grains with two different orientations which were rotated by 45°. Scanning electron microscopy (SEM) of the film surface showed the films to consist of a smooth background surface and a distribution of particles. Energy dispersive X-ray analysis (EDAX) measurements showed that the Ba concentration was larger than that of exact stoichiometric composition. Auger electron spectroscopy (AES) revealed that the elements contained in the particles were richer in Ba than in the smooth background surface. The BaCuO2 particles seemed to precipitate on the surface of the film.

YBa2Cu3Oy (YBCO) superconducting thin films were deposited on MgO single crystals by induction-coil-coupled sputtering. The effects of the induction coil on the qualities of YBCO thin films are examined. Uniformity of film thicknesses below ±5% was obtained over an area of 40 mm diameter using a 50 mm diameter target by the condition of the substrate-target distance of 90 mm. Even in the area of 60 mm diameter which was wider than that of the target, the uniformity of thickness within ±17% was obtained. In order to clarify the effects of the induction-coil, we studied the dependence of the critical temperature (Tc) and the full width at half maximum (FWHM) of the films on the applying power of coil. Tc and FWHM showed optimum values at the applying coil power of 70W. It is confirmed from these results that the induction-coil operated effectively to fabricate high quality films. The epitaxial relations of YBCO films on MgO single crystal substrates were examined by X-ray pole figure measurements. Basically film of YBCO was aligned with the c-axis perpendicular to the substrate surface. The film deposited at the coil power of 70W exhibited well single-oriented grains with the a- or b-axis parallel to the a-axis of MgO. However, films deposited at the applying coil power of 0W contained grains with two different orientations which were rotated by 45°. Scanning electron microscopy (SEM) of the film surface showed the films to consist of a smooth background surface and a distribution of particles. Energy dispersive X-ray analysis (EDAX) measurements showed that the Ba concentration was larger than that of exact stoichiometric composition. Auger electron spectroscopy (AES) revealed that the elements contained in the particles were richer in Ba than in the smooth background surface. The BaCuO2 particles seemed to precipitate on the surface of the film.

We have studied the performances of several types of vortex flow transistors including prototype flux flow transistors (FFTs), nanobridge vortex flow transistors (NBVFTs) based on a parallel array of nanobridges, planar Josephson vortex flow transistors (planar JVFTs) based on a parallel array of grain boundary Josephson junctions, and JVFTs with a stacked structure (stacked JVFTs). The NBVFTs had considerably higher magnetic field sensitivity and shorter response time than the FFTs. A flux-to-voltage transfer function dV/dG> of 2.6 m V/(Z>0 and a modulation depth of 0.5mV were obtained for the NBVFT composed of 2 nanobridges, while the current gain was small. The temperature dependence of the device parameters (the dynamic resistance and the inductance) suggests that the surface barrier to the Abrikosov vortex entry into the nanobridge strongly contributes to the relatively large dV/dQ values. The response time of the nanobridge is estimated to be 5 ps. On the other hand, the JVFTs showed large current gains because of the small kinetic inductance of the Josephson junction. The planar JVFT composed of 3 Josephson junctions with an asymmetrical geometry showed a current gain of 2.2 at 4.2 K. Also, the stacked JVFT showed the current gain of 2.0, while the maximum value of dV/dd> was 210/iV/OV The mutual inductance between the control line and the superconducting loop within the transistor was enhanced in the stacked JVFT. This enhancement may yield a short response time compared to that of the planar JVFT. When we apply these vortex flow transistors, we should take account of the properties peculiar to each transistor.

We study variations of the order parameter and the vector potential with time using the rescaled time-dependent Ginzburg-Landau (TDGL) equation. Computer simulations for several conditions are performed to discuss the bias current distribution and the time necessary for the transition from the normal state to the superconducting state for the superconducting narrow line. As a result, we have found that the time necessary for the transition from the normal state to the superconducting state is an important factor to explain the I-V characteristics due to the vortex motion in superconducting narrow lines. © 1996 IOP Publishing Ltd.

A miniaturization of high critical temperature (T-c) superconducting flux flow transistor (SFFT) was studied. The weak link width in the direction of the vortex flow was varied from 5 mu m to 10 mu m. The weak link length in the direction of bias current flow was fixed to 5 mu m. An increase in the gain was observed as the weak link width decreased. A control line was placed close to the weak link in the distance of 0.5 mu m to compensate for a decrease of magnetic sensitivity due to the miniaturization. We also improved the characteristics of the SFFT by forming a corrugated structure, which is named corrugation flux flow transistor (CFFT). A submicron patterning of YBa2Cu3Oy (YBCO) thin film was performed using focused ion beam lithography. Furthermore, we demonstrated a micro flux flow transistor (MFFT) consisting of a single bridge. The MFFT also operated as well as the CFFT.

We study the dynamics of vortex lines in superconducting flux flow transistors (SFFT's) made of High T-c superconductors, YBa2Cu3Ox. By computer simulations we have found that the density of vortex lines in SFFT's has close relation to device I-V characteristics rather than the velocity of vortex lines and that we have to increase the density of vortex lines to get ones with available gain. To be more concrete, in order to increase the density of vortex lines we have to lower surface barriers at the edge of weak-links and heighten the magnetic field near the edge of weak links. Especially, it is very important to heighten the magnetic field at the both sides of a link in a SFFT. Under the control of the control current, vortex lines in a SFFT are driven by the transport current (the bias current) mainly, but it is important to think the other forces such as the force by screening current, the force induced by the other vortices and the force induced by the image vortices. Based on the local stochastic equation of motion for vortex lines, computer simulations for some conditions are performed to discuss the dynamic behavior of vortex lines in a SFFT. We report the effect of the external magnetic field induced by the control current on the motion of vortex lines in SFFT's.

The variation of critical current density with reduced line width and the temperature dependence of voltage for superconducting narrow lines are calculated theoretically. Critical currents of superconducting narrow lines increase progressively as the lines become narrower. The surface barriers for superconducting narrow lines are discussed in order to understand the progressive increase in critical currents of superconducting narrow lines. Furthermore, the thermally activated flux lines jumping over the surface barrier are discussed ill order to understand the temperature dependence of voltage for superconducting narrow lines. The results of calculation using the surface barriers agree well with experimental results.

Critical current densities (Jc’s) of submicron YBa2CuaOy (YBCO) lines were studied. Increase in Jc with reduc­tion of line width (w) was observed reproducibly, when temperature rise of the substrate is suppressed during plasma etching of YBCO. Intermittent etching and liquid-nitrogen cooling were very effective in obtaining sufficient cooling. Temperature dependence of current-voltage characteristics was interpreted in terms of thermal­ly activated vortex motion. This result indicated the existence of a potential barrier to vortex motion. In particu­lar, the surface barrier played an important role in determining Jc in the submicron lines. Furthermore, the depen­dence of Jc on w was strongly dependent on the current concentration to the edges due to Meissner effect. © 1995 The Japan Society of Applied Physics.

We have developed a new technique for YBa2Cu3Oy (YBCO) submicron structure formation. Nb films serving as etching masks are patterned into line structures with submicron dimensions, using focused ion beam lithography and a vertical etching technique of the Nb films. Then the mask patterns are accurately transferred to the YBCO film in an electron cyclotron resonance plasma etcher. Fine lines are successfully patterned down to 180 nm of the linewidth without any degradation of superconductivity, as long as a temperature rise is suppressed during plasma etching. The temperature dependence of the current-voltage characteristics can be interpreted in terms of the thermally activated vortex motion.

The dependence of the gap voltage on impurities in Nb films is studied. The gap voltage is determined by the number of impurities included in the films. The impurities arise from the residual gas in the sputtering chamber before the deposition of Nb films. By reducing the impurities in the films, we obtain high-quality Nb/AlO(x)-Al/Nb Josephson junctions having the gap voltage of 2.95 mV which is close to that estimated from the energy gap of Nb bulk at 4.2 K. In addition, the use of a thin Al layer is also an important factor in obtaining excellent current-voltage characteristics.

ハイドロキシアパタイト（HAp）は歯や骨の主成分であり、生体適合性に優れているため、これまで人工骨や人工歯根をはじめとするインプラント素材として、広く医療分野に用いられている。しかし、HApはセラミックスであるため柔軟性に乏しく、硬くて脆いという欠点を持っており、これがHApの医療分野での応用の限界を決めていた。我々はHApのみからなる柔軟な極薄HApシートを開発することに成功し、このフレキシブルHApシートの歯科分野への応用を開始したので紹介した。

キラル媒質を中心とする人工電磁波媒質に関する内容を専門外の読者を対象として平易に解説した。

3次元的アンカリング効果をもつエンドポアインプラント表面に、レーザアブレーション法で高結晶性のハイドロキシアパタイト薄膜を成膜し、生体親和性の向上を図った。レーザアブレーション時のガス圧を高く設定することでアブレーション化学種とガス分子の衝突・散乱を増加させ、ポア深部への成膜を行なった。得られた試料を動物実験に用いたところ、μCT像によりポア深部への新生骨伝導が認められた（英文）。

We have successfully created a flexible hydroxyapatite (HAp) sheet of less than a few micrometers, and we have been trying to establish the all-HAp restoration technique for tooth enamel. In this study, we evaluated the re-calcification layer at the various sheets (amorphous HAp, HAp, amorphous HAp/amorphous calcium phosphate: ACP, HAp/ACP)-enamel interface by scanning electron microscope (SEM).

We studied a method to obtain superconductivity even in very thin films of YBa2Cu3Oy (YBCO). These thinner YBCO films will be able to be applied to optics/superconductivity (opt/super) converters with high optical sensitivity. Opt/super converters composed of YBCO nano-bridges or nano-wires require a low critical current that is determined by the film thickness. According to X-ray diffraction, critical temperature (Tc) and residual resistivity ratio for the substrates of MgO (100), SrTiO 3 (100) and NdGaO3 (110), superconducting features are influenced by the lattice mismatching layer in YBCO closing to a hetero-epitaxy interface between YBCO and single crystal substrate. YBCO films with different thicknesses varying from 80 to 10 nm were prepared on SrTiO3, using a suitable temperature. The values of Tc slightly decreased when reducing YBCO thickness from 80 to 20 nm, and then declined sharply at less than 20 nm. It is considered that a layer in the beginning of deposition less than 20 nm causes stress in the crystal lattice. The Tc of 20 nm YBCO film on SrTiO3 was 80.8 K. It can work above liquid N2 temperature. © 2012 The Institute of Electrical Engineers of Japan.

We have fabricated a flexible hydroxyapatite (HAp) using a pulsed laser deposition (PLD) method and a film isolation technique. We adhered the HAp sheet to the dentine surface using a calcium phosphate aqueous in order to apply this sheet to hyperesthetic treatment. In the present study, the time dependence of the composition at the interfaces between the HAp/TCP sheet and the dentine was evaluated using X-ray diffraction measurement, and the adhesive strength between the HAp/TCP sheet and the dentine surface was evaluated by quasi-static tensile tests.

We have succeeded to fabricate flexible hydroxyapatite (HAp) sheet for adhering directly onto tooth and bone surfaces using a pulsed laser deposition method and a film isolation technique. We have investigated a method to regenerate the tooth enamel by just attaching the flexible HAp sheet onto the tooth surface with artificial saliva. In this paper, we report the result of adhering the HAp sheet to the enamel assisted by an TCP over-deposition and calcium phosphate aqueous solution in order to reduce the period required to regenerate the enamel.

To improve osteoblasts attachment to a porous implant such as artificial tooth root, plasma spray coating of hydroxyapatite (HA) has been attempted applying. However, plasma sprayed HA powders plugged up a way in holes of the porous structure which is important way of bone growth. To solve this problem, in this experiment, HA thin film 300nm thick was deposited by pulsed laser deposition (PLD) technique on the tooth root. HA thin film was reached easily to the depth of the porous structure. In 3 weeks after operation, the bone in-growth speed in HA-deposited tooth root was increased as compared with non HA-deposited one. In 5 weeks after operation, no particular difference between HA-deposited and non HA-deposited tooth roots was found. HA thin film deposition on a porous implant was effective in the improvement of osteoblast attachment.

The effect of in-plane 0-45° grain boundaries on surface resistance (Rs) of c-axis YBa2Cu3Oy (YBCO) films on MgO substrates is discussed. Samples that have various densities of 45° rotated grains were prepared using a self-template technique. The Rs values at 22 GHz were measured by the dielectric resonator method using a cryocooler. The Rs systematically changed corresponding to the amount of 0-45° grain boundaries. Conspicuous feature of the films including 0-45° grain boundaries is a large residual surface resistance. The Rs of almost perfectly in-plane aligned YBCO film scaled to 10 GHz were 0.12 mΩ at 20 K and 0.67 mΩ at 77 K on the assumption of tan δ = 0, respectively.

超伝導体は常伝導金属に比べてマイクロ波領域において2ケタほど小さな表面抵抗を持つことから、超伝導を用いた高効率あるいは小型なアンテナやフィルタ、伝送線路等のマイクロ波、ミリ波デバイスの実現が期待されている。特に、今回報告するパッチアンテナにおいては、多素子化されたアレーアンテナにおいて問題となる給電線の損失を大幅に低減できるため、従来のアンテナに比べて高利得のアレーアンテナが作製できることが予想される。

酸化物高温超伝導材料のマイクロ波応用の発展に伴い、薄膜の大面積化が求められている。我々は、大口径かつ均一な高密度プラズマを発生させることができる誘導コイル結合型スパッタリンダ法を大面積薄膜作製法として有望視しており、これを用いてYBa_2Cu_3O_y薄膜作製条件の検討を行っている。現在までに、ある条件下ではφ50mmの基板面内での膜厚分布が5%以下であること、また誘導コイル投入電力によりTc及び結晶の配向制御が可能であることを示した。しかし、誘導コイル投入電力、カソード電圧、カソード電流はそのうち2者を決定すると残りの1者が自ずから定まるという関係にあるため、同時に2つの成膜パラメータを変化させることとなり、各々がどの様に膜質を支配しているかが明確ではなかった。今回、膜質と上記パラメータの関係について調べ、中でもTcの決定にはカソード電圧が重要であることが明らかとなったので報告する。

超伝導フィルタは、高周波領域における表面抵抗が常伝導体のそれに比べ1桁以上低いため、低挿入損失、シャープカット特性等の優れた特性を有し、移動体通信の基地局用フィルタとして注目されている。現在検討されている超伝導フィルタは、分布定数型では、例えばヘアピン形、櫛形、平行結合形、コプレーナフィルタ等が多いが、高効率化のためには同じ性能でも面積の小さいフィルタを作製する方が有利である。我々は、ヘアピン、櫛形、平行結合形フィルタの形状の最適化とサイズの小型化を検討している。

これまでに東京都健康長寿医療センター研究所とのプロジェクトチームが実施した板橋区の検診において，ジョイントしKINECTを使って高齢者に１回の起居動作と開眼での20秒間その場足踏み（マーチ）テストを1500人に近い大量データを収集した。検診データは研究所において厳重に管理されており，この起居とマーチ時KINECTデータのみを持ち帰り解析を行ってきた。その解析が一人一人の動画を確認しながら行うという状況で大量データの分析プログラムが必要となったこと、歩行数などの新たな追加変数の解析が必要となり，共同研究者の小濱准教授，楠教授によってプログラムの修正を試みた。解析は可能となったが，KINECTデータと研究所に集積されたデータとの連結がコロナ感染予防のために東京への出張等全て禁止となり，データの操作が全くできない環境に陥っていたが，外出移動の緩和に伴い，少しずつであるが解析を進め，その結果から 1) Falling history associated with 20-sec stepping test movement displacement in independent, community-dwelling older women，2) Age-associated decline in 20-sec stepping test performance in independent, community-dwelling older women, 3) Head-knee movement pattern during a 20-sec stepping test discriminates dependent- from independent-living older womenについて比較検討した。これらの結果は，令和４年（2022年）度アメリカスポーツ医学会及び世界大会（サンディエゴ）において成果を公表する予定である。また，これらの成果は最終年度において論文化を行う計画である。また，フレイル，サルコペニア，軽度認知症などの変数との関連性も検討している。

クロマトグラフィーチップやバイオセンサの高感度化、高分解能化などを目指し、ハイドロキシアパタイト(HA)結晶膜の配向制御技術を確立し、そのデバイス応用の可能性について調べた。完全なa面配向とc面配向のHA膜を作り分ける手法を新たに開発し、その結晶成長メカニズムも明らかにした。ここで得られた配向制御膜を用いて、酸性タンパク・塩基性タンパクの選択的吸着が可能であることを示唆する結果が得られた。これを電気的に検出するため水晶振動子マイクロバランスセンサへの適用を試みたが、HAの結晶化に必要な熱処理に起因する歪により正常動作するには至らず、さらなる改良が必要であることが分かった。

本研究はシート状のアパタイトを歯質表面に貼り付けることにより、齲蝕の防止ができる歯科用新素材開発を大目標としており、当研究助成期間内には「フッ素含有率･結晶性傾斜型F-Ap/H-Apシート」を開発することまでを目的としている。ここで、F-Apはフッ化アパタイト[Ca10(PO4)6F2]、H-Apはハイドロキシアパタイト[Ca10(PO4)6(OH)2]の意味であり、表面に耐酸性が強く齲蝕しにくい高結晶性F-Ap、裏面に歯質と結合しやすい低結晶性H-Apの構造を有する歯科治療・予防用素材を実現する。H25年度までに、パルスレーザーデポジション法でF-Ap膜の作製法を確立した。エネルギー分散型X線分光分析法（EDX）と赤外分光法（FT-IR）を用いた評価により、OH基を全く含まない純粋なF-Ap膜が形成可能であること、また、X線回折（XRD）により結晶構造を有する（アモルファスでない）F-Ap膜が形成される条件を得ることができた。耐酸性に関しては、pHの異なるリン酸バッファー溶液を用いた溶解試験を行った結果、H-Apの場合と比べて耐酸性が向上していることが証明された。F-Ap/H-Apの2層膜化に関しては、同一チャンバ内でターゲットを変更することで実現できることまでを確認している。アニーリングによるフッ素含有率･結晶性の傾斜構造の作製については、当年度内で行うに至らず、最終年度の課題として残った。当初計画で掲げたスパッタリング法を用いた場合のF-Ap膜の作製と、そのレーザーデポジション法との比較については、現在まで試みた成膜条件においては、前者の成膜レートが１桁以上低く、数ミクロンレベルの厚みを有する自立型シートを作製するには現有設備の範囲内で行うには効率が悪いと結論付けた。成膜装置の変更を伴う将来への可能性を残しつつ、以後の実験はパルスレーザーデポジション法で行うこととした。

本研究の新奇性のひとつは、3Dプリンタを用いてエンジニアリングプラスチック（EP）製ヒト海綿骨を作製することである。H25年度、3Dプリンタを用いた製造技術が世界で脚光を浴び、経済産業省が各種企業等へ導入奨励したのは周知である。本研究はこの影響を受け、外注先に突然多数の加工が発注されたため人工骨の納期が遅延した。一方、本研究課題がこのような世情を的確に捉えていたことを実感した年でもあった。H24年度の予備的研究を本実験に移して実施し、公表可能な成果を得て一部を発表した。また、H24年度の射出成形で製作したEPに対応する本実験として、3Dプリンタで製作したEP材の一般強度実験、切削性実験を完了し、強度は構造形態を最適設計することで生体骨と同等レベルに調整できることおよび被削性は生体骨より優れ、本人工骨は人工関節軟骨の下骨として必要十分な機械的特性を有することを明らかにした。H24年度は3D造形基材へ被覆したチタン（Ti）薄膜の密着性とその表面での単純な細胞増殖実験を行い、良好な生体親和性をEPに付与できることを確認した。H25年度は、Ti薄膜を人工骨の複雑な内部構造深部まで到達させるための条件検索と骨芽細胞の増殖能だけでなく分化能も確認した。Ti薄膜の被覆性につき、生体骨を模倣した構造において空孔の表面から内部へ 5 mm の深部に至る被覆の到達を確認した。同外形寸法のより単純な幾何学的構造では、Ti薄膜は構造の内外全体に成膜され、本課題で採用したスパッタリング法が人工骨に対して優れた被覆性を示すことを確認した。細胞の増殖・分化能は、構造の表面粗さに大きく影響された。最適な表面粗さ値および濡れ性が存在することが示唆され、H26年度の研究で追究する。

量子暗号通信のキーデバイスである単一光子検出器として、高温超伝導体でナノワイヤーを実現するための要素技術についての研究を行った。高温超伝導材料にはYBa_2Cu_3O_y(YBCO)を用いて実験を行い、Pt/Auのキャップ層を持つYBCO膜で、250回折り返された、全長約25mm、幅200nmのメアンダ型ナノワイヤーを100×100μm四方の領域に形成できることを示した。また、YBCOエッチング時に試料ステージを液体窒素冷却することにより、プラズマ衝撃による劣化の影響を抑制し、幅200nm、長さ1μmのワイヤーで超伝導電流を確認した。さらに、YBCOと単結晶基板のヘテロ界面近傍における格子不整合について検討し、20nmの膜厚でも80K以上の臨界温度(T_c)を持つYBCO膜の作製に成功した。一方、80～10nmの範囲で膜厚とT_cの関係を調べ、実効的に膜厚10nm以下の特性を有する高温超伝導ナノワイヤー実現の可能性を示し、その方法について述べた。

関節軟骨の病変部だけを人工軟骨に置換するための材料開発とそれを骨組織に永続的に固定する方法を研究した。人工軟骨であるポリビニールゲルが生体軟骨と摩擦する面は生体不活性、骨との接触面は強く接着できる部位選択組織融合型接着方法を研究した。接着層としてハイドロキシアパタイト積層超薄膜(厚さ350nm)を利用することとし、ゲルとアパタイト薄膜の生体適合性ならびに材料学的・力学的特性の向上方法を検索した。

レーザーアブレーション法によるハイドロキシアパタイト(HAp)と生体アパタイト(BAp)の薄膜化および積層化技術と、シート化技術を用いて、治療部位に整合した生体活性を有する骨誘導再生用BApメンブレン(BApGBR)と生体内安定性と生体活性を併せ持つ複合機能2層(BAp/HAp)インプラントを作製した。薄膜および積層膜の評価は化学的、物理的、分子生物学的特性について行った。また、BApGBRメンブレンと新規複合機能インプラントの臨床模擬試験を、イヌ下顎歯槽骨および大腿骨欠損モデル埋入試験を用い、次世代インプラント治療としての有用性を確認した。

サブテラヘルツ領域で動作する集積回路として注目されている、単一磁束量子(SFQ)回路の光出力インターフェースの基本素子として、高温超伝導ナノブリッジの作製プロセスの開発を行った。数100nm程度のスケールを有する高温超伝導ナノブリッジを用いた微小ループを基本構造とし、そこに閉じ込めたSFQを磁気光学効果により検出するデバイスを想定し、その作製法を検討した。さらにナノブリッジを光入力デバイスとして動作させることも試み、その光応答を確認した。

水晶振動子マイクロバランス(以下QCMと記す.)法は,振動子の振動数が液体,気体などの媒質中の含有物,微粒子の化学物質の吸着量に応じた変化に基づいてホストを発振子上に固定すればゲストの吸着量をナノレベルで検出出来る.本研究ではその原理を利用して,歯科に特化したオリジナルなセンサを創製することを目的とする.薄膜チタンの細胞適合性評価:Na, Mg, K, Zn等の微量元素を含む牛大腿骨を原料とした生体アパタイトバルク体を作製し,レーザーアブレーションを行うことによってチタン基板上に同薄膜を作製した.その生体適合性についてマウス骨芽細胞を用いてin vitro試験法によって評価した.その結果,化学量論的HAP薄膜に比較して生体アパタイト薄膜で優れた生体適合性を示した.製造方法によって異なる形態をもつ,結晶化HApとアモルファスHApについて,その吸着性についての評価を行った.方法として,定量測定が可能なQCM法を用い,レーザーアブレーション法(PLA法)によるハイドロキシアパタイトコートセンサを作製した.生体分子としてタンパク質(BSA)を用いてこれらの薄膜の吸着特性を比較した結果,いずれのHApコートセンサも市販のセンサに比べ高い吸着性を示した.アモルファスHApは結晶化HApよりは吸着性が劣っていたが,生体親和性材料として応用が可能であることが確認できた.QCM法による歯質表面汚染ならびに除去のモニタリング試験を行った.歯質センサとしてPLA法による生体アパタイトコートセンサを作製した.歯質センサと歯質汚染原因物質の一つである茶葉との結合をモニタリングした.紅茶葉溶液との結合によって周波数が減少し,歯磨剤成分(ポリリン酸ナトリウム等)を添加することで周波数が増加し,除去したことが明らかとなった.

本研究は,地域在住高齢者の機能的自立と健康づくりを支援するためにITを導入した運動方法システムの構築を目指すことが目標であった。施設または集中型運動方法としては,これまでにwell-rounded exerciseおよびresistance exerciseの機器として油圧マシンを改良し,筋力,筋パワーを瞬時に測定し,評価できるシステムを開発した。特に地域に居住しているが介護保険を利用する虚弱高齢者においての体力評価または運動効果の評価までを可能にするシステムができ有効なものとみられた。加速度形付歩数計を用いて高齢者自身が日常生活における身体活動を評価し,入力後瞬時にフィードバックできるシステムを開発し,介入効果も検討できた。これは,タッチパネル式の入力を可能にしたものであり,集中,分散型に対応したものといえる。油圧マシン,加速度計付歩数計などの機器を使った体力,身体活動量の評価は実施でき,かつ,体力の評価ノルムを作成すること,エアロビクス,レジスタンンス,柔軟性,バランスなどの運動効果を検討し,メニューの作成まで完了できたが,これらツールとして体力評価から運動方法の具体的例示などのフィードバックまでに至るITを完全利用したシステム構築までには至らなかった。この点は早急に開発を目指したい。運動の継続や容易性という点からは公民館などを中心とした地域型運動プログラムと家庭型運動プログラムの併用が求められるものの,地域差や季節差に対する運動プログラムの対応や家庭型運動に加えて集団指導(地域型運動)をいかに取り入れていくかが継続と効果の課題とみられる

移動体通信基地局用超伝導フィルタの産業化に先立ち、母材となる高温超伝導薄膜の高周波表面抵抗測定・検査技術に関しての研究を行った。初年度、(1)「導体損<<誘電損となりQ値が誘電損でほぼ決定されてしまうこと」、(2)「Qが10^6〜10^7にも達し、微弱ノイズなどによる測定誤差が無視できなくなること」など、従来の標準測定法が抱える問題点を明らかにし、測定周波数をミリ波領域に高めることでこれらが解決できることを理論的・実験的に示した。最終年度となる本年は、さらに高精度測定を行うことを目的に、共振器を構成するサファイアロッドの持つ誘電損に関する個体間の僅かなばらつきに着目し、標準測定法(2共振器法)を用いた際にこれが起源となって生じる誤差の検討を行った。第一に市販のサファイアロッドのもつ誘電損のばらつきを実測によるサンプリングで把握した。これをもとに現実的な表面抵抗を想定した数値計算によるシミュレーションを行い、生じ得る誤差の範囲を見積もった。この結果、各共振モードに対応するサファイアロッドの選択、または組み合わせによって、表面抵抗に含まれる誤差を増加させる状況が起こり得ること、さらには市販品の持つばらつきの現状を考慮するとその確立が無視できないことが明らかとなった。これを改善し高精度計測を行うためには、従来無視してきたサファイアロッドの誘電損の見積もり・選択がきわめて重要なことを明らかにした。また、この誘電損に起因する誤差は、初年度行った、ミリ波帯での計測を行うことにより軽減できることも示した。

超伝導フィルタ、アンテナに関して、ドイツ ブッパタール大学のProf.Heintz Chaloupkaと共同研究を行い、次の様な成果を得ている。1. 平成9年度楠 正暢助手がProf.Heintz Chaloupkaの研究室に3週間滞在し、超伝導フィルタの設計・試作に関して共同研究を行ってきた。山形大学では高温超伝導薄膜(YBa_2Cu_3O_7-δ)の作製とその評価、超伝導フィルタの設計について主に研究し、ドイツ ブッパタール大学では、超伝導フィルタの設計・試作・評価を主に研究した。2. 平成10年度Prof.Heintz Chaloupkaが山形大学工学部大嶋研究室に3週間滞在し、超伝導フィルタに関する共同研究を行った。Prof.Heintz Chaloupkaが山形大学に滞在している期間に、日独超伝導フィルタシンポジウムを開催し、Prof.Heintz Chaloupka、移動体通信先端技術研究所、松下電器、山形大学から最近の研究成果を発表してもらった。超伝導フィルタの開発を目的とした、山形大学とブッパタール大学との研究交流は、平成10年度以降も継続される。

スーパーゲイン小形超伝導アンテナに関して、次の4点を重点的に検討し成果を得た。1.マイクロ波帯で動作するパッチアンテナの設計法の確立マイクロ波帯で動作するアンテナを伝送線路モデルおよび市販の電磁界解析ソフトを用いて行った。共振周波数5GHz、入力インピーダンス50オームとなるパッチアンテナを設計し、その設計に基づき銅薄膜のアンテナを試作し、伝送線路モデルの有効性を確認した。2.超伝導アンテナの設計、試作、評価YBCO薄膜を用いてパッチアンテナを試作し、アンテナ特性を評価した。その結果、共振周波数はほぼ設計通りの値を示したが、入力インピーダンスは設計値よりも大きな値となった。この違いを、電磁界シュミレーションにより検討した結果、超伝導薄膜の表面抵抗が設計値よりも小さいためであることがわかった。超伝導アンテナの利得は金薄膜で作製したアンテナよりも数dB以上高いことが明らかとなった。3.アンテナ用超伝導薄膜の作製法の検討超伝導アンテナを作製する場合、比較的面積の広い薄膜が要求される。我々は、誘導コイル結合型マグネトロンスパッタリング法によりその作製を検討し、アンテナに使用できる薄膜の作製法を確立した。4.アレーアンテナの検討2素子、4素子のパッチアレーアンテナを設計、試作、評価を行った。その結果、素子数を増やす事により利得の増加があること、超伝導アレーアンテナは銅薄膜アレーアンテナよりも4dB以上利得が高いことを明らかにした。

サブミリ波超伝導アレーアンテナの試作に関して、次の4点を重点的に検討し成果を得た。1.マイクロ波〜ミリ波帯で動作するパッチアンテナの設計法の確立マイクロ波帯で動作するアンテナの設計法をまず検討した。アンテナを設計する手法は、伝送線路モデルおよび市販の電磁界解析ソフトを用いて行った。共振周波数5GHz、入力インピーダンス50オームとなるパッチアンテナを設計し、その設計に基づき銅薄膜のアンテナを試作し、伝送線路モデルの有効性を確認した。2.超伝導アンテナの設計、試作、評価YBCO薄膜を用いてパッチアンテナを試作し、アンテナ特性を評価した。その結果、共振周波数はほぼ設計通りの値を示したが、入力インピーダンスは設計値よりも大きな値となった。これは、超伝導の表面抵抗起因していることが明らかとなった。超伝導アンテナの利得は金薄膜で作製したアンテナよりも数dB以上高い。3.アンテナ用超伝導薄膜の作製法の検討超伝導アンテナを作製する場合、比較的面積の広い薄膜が要求される。我々は、誘導コイル結合型マグネトロンスパッタリング法により作製を検討し、アンテナに使用できる薄膜の作製法を確立した。4.ミリ波〜サブミリ波用ログペリアンテナの検討ミリ波、サブミリ波で動作するログペリアンテナを設計、検討した。サブミリ波帯で動作するためには、アンテナ共振器長が数ミクロンとなるために、精密なフォト加工によりアンテナを制作した。40GHzまでの動作を確認したが、残念ながらそれ以上の周波数での検証ができないので、今後検討する。