詳細

井上　修平 （イノウエ　シュウヘイ）

  • 工学部 機械工学科　教授
Last Updated :2024/04/25

コミュニケーション情報 byコメンテータガイド

  • コメント

    未利用熱の有効利用に向けた電池の開発や、カーボンナノチューブを使ったユビキタスガスセンサーの開発を進めています。マイクロナノ領域での熱や物質の移動現象に興味があります。

研究者情報

学位

  • 博士（工学）（2003年03月 東京大学）

ホームページURL

科研費研究者番号

  • 60379899

Researcher ID

  • D-6153-2011

J-Global ID

現在の研究分野（キーワード）

    未利用熱の有効利用に向けた電池の開発や、カーボンナノチューブを使ったユビキタスガスセンサーの開発を進めています。マイクロナノ領域での熱や物質の移動現象に興味があります。

研究分野

  • ナノテク・材料 / 薄膜、表面界面物性

経歴

  • 2022年04月 - 現在  近畿大学工学部教授
  • 2020年04月 - 2022年03月  広島大学大学院先進理工系科学研究科准教授
  • 2009年04月 - 2020年03月  広島大学大学院工学研究科准教授
  • 2007年04月 - 2009年03月  広島大学大学院工学研究科助教
  • 2004年04月 - 2007年03月  広島大学大学院工学研究科助手
  • 2002年04月 - 2004年03月  独立行政法人日本学術振興会特別研究員

学歴

  • 2000年04月 - 2003年03月   東京大学   大学院工学系研究科   機械工学専攻
  • 1998年04月 - 2000年03月   東京大学   大学院工学系研究科   機械工学専攻
  • 1993年04月 - 1998年03月   慶應義塾大学   理工学部   機械工学科

研究活動情報

論文

  • Mohammed Ahmed Mohammed Ali; Shuhei Inoue; Yukihiko Matsumura
    The Journal of Supercritical Fluids 190 105755 - 105755 2022年11月 [査読有り]
  • Jayapiriya U S; Shuhei Inoue; Sanket Goel
    Biosensors and Bioelectronics 214 114479 - 114479 2022年10月 [査読有り]
  • Mengli Zhang; Shuhei Inoue; Yukihiko Matsumura
    Chemical Physics Letters 798 139596 - 139596 2022年07月 [査読有り]
     
    Herein, we prepared a multi-walled carbon nanotube (MWCNT) paper by filtration, and tested its gas-sensing ability toward polar and non-polar organic solvents by comparing the magnitude of the adsorption sensitivity, response time, and reproducibility. The adsorption of non-polar organic solvents showed multilayered behavior; we presume that a stable adsorption layer is prevented from being formed owing to the measurement temperature used being higher than the critical gas temperature.
  • Mohammed Ahmed Mohammed Ali; Shuhei Inoue; Yukihiko Matsumura
    The Journal of Supercritical Fluids 182 105532 - 105532 2022年03月 [査読有り]
  • Yutaro Suzuki; Hidetaka Takaki; Shuhei Inoue; Yukihiko Matsumura
    AIP Advances 11 8 085108 - 085108 2021年08月 [査読有り]
  • Hidetaka Takaki; Shuhei Inoue; Yukihiko Matsumura
    Chemical Physics Letters 774 138624 - 138624 2021年07月 [査読有り]
  • Shuhei Inoue; Kento Tobinaga; Kou Suzuki; Yukihiko Matsumura
    Chemical Physics Letters 759 137974 - 137974 2020年11月
  • Muxuan Zou; Yoshinori Aono; Shuhei Inoue; Yukihiko Matsumura
    Materials 13 20 4568 - 4568 2020年10月 [査読有り]
     
    To develop a high-performance hydrogen gas sensor, we fabricated a composite film made of carbon nanotubes (CNTs) and palladium nanoparticles. Carbon nanotubes were spin-coated onto a glass substrate, and subsequently, palladium nanoparticles were sputtered onto this film. The response to hydrogen gas was measured during two seasons (summer and winter) using a vacuum chamber by introducing a hydrogen/argon gas mixture. There was a clear difference in the sensor response despite the temperature difference between summer and winter. In addition, since a clean chamber was used, fewer water molecules acted as a dopant, and the behavior of the CNT changed from p-type to n-type because of the dissociative adsorption of hydrogen. This phenomenon was confirmed as the Seebeck effect. Finally, the work functions of Pd, PdHx, and CNT were calculated by first-principle calculations. As predicted by previous studies, a decrease in work function due to hydrogen adsorption was confirmed; however, the electron transfer to CNT was not appropriate from the perspective of charge neutrality and was found to be localized at the Pd/CNT interface. It seems that the Seebeck effect causes the concentration of conductive carriers to change.
  • Pattraporn Changsuwan; Shuhei Inoue; Yukihiko Matsumura
    ACS Omega 5 38 24818 - 24825 2020年09月 [査読有り]
  • Zhang, Mengli; Inoue, Shuhei; Matsumura, Yukihiko
    CHEMICAL PHYSICS LETTERS 747 ELSEVIER 2020年05月 [査読有り]
     
    In order to achieve light and flexible gas sensor, we fabricated a uniform carbon nanotube paper made by multiwalled carbon nanotube and employed it as a sensing part. Referring to the transient behavior, it was clarified that the sensor response followed Langmuir isotherm, similar to the previous results prepared on a glass substrate. A repetition characteristics was quite stable and sensitivity was higher than previous one. Thus, it opens prospects for application, but it is unclear why the sensitivity is high despite the increased thickness.
  • Takaki, Hidetaka; Shinzato, Keita; Inoue, Shuhei; Miyaoka, Hiroki; Ichikawa, Takayuki; Matsumura, Yukihiko
    CHEMICAL PHYSICS LETTERS 739 ELSEVIER 2020年01月 [査読有り]
     
    We investigated the photochromism in a double-layer metal oxide by using X-ray photoelectron spectroscopy and scanning electron microscopy to identify the UV-induced reversible photochromism. We observed the metal oxide was reduced to a partially formed crystalline metal, and this was the cause of the photochromism. It was also found that this reduction induced by UV irradiation cracked the upper layer of magnesium-tin oxide and ultimately caused the reduced metal to oxidize slightly by being exposed to the atmosphere. This reversible transformation of a chemical species, on UV exposure, and discoloration induced by heating was considered to be a redox reaction.
  • Inoue, Shuhei; Tomita, Yoshihiro; Matsumura, Yukihiko
    CHEMICAL PHYSICS LETTERS 734 ELSEVIER 2019年11月 [査読有り]
     
    Molecular adsorption on carbon nanotube (CNT) films follows the Langmuir adsorption isotherm even for polar molecules at low gas pressures. Therefore, this film can be applied to gas sensors. In order to clarify the effect of thickness on sensor response, we fabricated CNT films of different thicknesses and observed their behavior. Because the adsorption is expected to occur near the surface, we determined the effective penetration thickness for the gas molecules and identified an approximate thickness of 7 mu m.
  • Takaki, Hidetaka; Inoue, Shuhei; Matsumura, Yukihiko
    CHEMICAL PHYSICS LETTERS 732 ELSEVIER 2019年10月 [査読有り]
     
    To reveal the photochromism (PC) in double-layer metal oxide films, we investigated reduction, considered to be the cause of PC, by XPS and confirmed reduction occurred near the interface. We synthesized various double-layer metal oxide films to investigate the conditions for PC and confirmed several showed PC than reported to date. From these results and consideration of the band structures of the systems, we suggest a mechanism for PC, involving electron movement through the interface and reduction of the interface by those electrons. Consequently, we found requirement about the electronic structure for PC to occur in double layer metal oxide.
  • Tobinaga, Kento; Inoue, Shuhei; Matsumura, Yukihiko
    CHEMICAL PHYSICS LETTERS 717 11 - 15 ELSEVIER SCIENCE BV 2019年02月 [査読有り]
     
    In order to obtain high quality white light, we synthesized yellow phosphors by doping europium and other lanthanoids such as holmium and lutetium. We successfully obtained yellow phosphors with green emissions with a wavelength of 510 nm for Li2SrSiO4 by co-doping europium and holmium. Unlike single doping of europium, a lower reduction temperature seemed to be preferable. When we simulated the chromaticity of white light at 5000 K, achieved by mixing blue light, which was used for excitation, and this phosphor, it resulted in better quality than commercially available products.
  • Kajiyama, Hiroshi; Kuhoyama, Shin; Otomo, Atsushi; Uyama, Hiroki; Matsuura, Toshihiro; Inoue, Shuhei; Matsumura, Yukihiko; Takata, Keiji; Tomita, Kentaro; Uchino, Kiichiro
    MRS ADVANCES 4 27 1573 - 1577 CAMBRIDGE UNIV PRESS 2019年02月 [査読有り]
     
    Photochromic (PC) ZnO nanoparticles are synthesized for the first time by using a VHF plasma enhanced CVD apparatus. The prepared ZnO film changes from transparent to PC state under UV irradiation; on being subjected to heat treatment, it changes back to transparent state. There is a threshold temperature for attaining the PC phase. The Debye-Waller factor of Zn atoms is specifically large for the PC ZnO. The ZnO nanoparticles contain carbon as impurity. The effects of C-O bonds on the ZnO crystal structure and density of states (DOS) are simulated based on density-functional theory. The results reveal that the crystal structure is slightly distorted and a sufficient DOS for PC light absorption is formed in the band gap.
  • Pattraporn Changsuwan; Nattacha Paksung; Shuhei Inoue; Takahito Inoue; Yoshifumi Kawai; Takashi Noguchi; Hiroaki Tanigawa; Yukihiko Matsumura
    J. Supercrit. Fluids 142 32 - 37 2018年12月 [査読有り]
  • Hidetaka Takaki; Shuhei Inoue; Yukihiko Matsumura
    Chemical Physics Letters 712 25 - 29 2018年11月 [査読有り]
  • Inoue, Shuhei; Tomita, Yoshihiro; Kokabu, Takuya; Matsumura, Yukihiko
    CHEMICAL PHYSICS LETTERS 709 77 - 81 ELSEVIER SCIENCE BV 2018年10月 [査読有り]
     
    In this study, we fabricated carbon nanotube films for application to gas sensors. We assumed that the ratio of electrical conductance change was equal to the surface coverage, and our detection model verified this assumption. To prove this assumption, we simulated the sheet resistance of a film with numerous joints. Our Monte Carlo simulations proved that when the joint resistance increased owing to molecular adsorption, the sheet resistance increased in accordance with the surface coverage.
  • Matsumura, Yukihiko; Goto, Satoshi; Takase, Yusuke; Inoue, Shuhei; Inoue, Takahito; Kawa, Yoshifumi; Noguchi, Takashi; Tanigawa, Hiroaki
    ENERGY & FUELS 32 9 9568 - 9571 AMER CHEMICAL SOC 2018年09月 [査読有り]
     
    Effect of organic acids on char suppression in supercritical water gasification (SCWG) was investigated. When acetic acid or formic acid was added to the SCWG of guaiacol, char production was suppressed. Acetic acid also effectively suppressed char formation in the SCWG of a Shochu residue. When an optimal amount of acetic acid was added, char production was drastically suppressed, while hydrogen was produced in excess of the added acetic acid. Further addition of acetic acid increased the char production as well as the production of methane and carbon dioxide. We believe that the organic acids function as radical scavengers to suppress char formation that usually occurs via a radical mechanism.
  • Shuhei Inoue; Supanat Lojindarat; Takahiro Kawamoto; Yukihiko Matsumura; Tawatchai Charinpanitkul
    Chemical Physics Letters 699 88 - 92 2018年05月 [査読有り]
     
    In this study, we explored the spontaneous and controlled-diameter growth of carbon nanotubes. We evaluated the effects of catalyst density, reduction time, and a number of catalyst coating on the substrate (for multi-walled carbon nanotubes) on the diameter of single-walled carbon nanotubes and the number of layers in few-walled carbon nanotubes. Increasing the catalyst density and reduction time increased the diameters of the carbon nanotubes, with the average diameter increasing from 1.05 nm to 1.86 nm for single-walled carbon nanotubes. Finally, we succeeded in synthesizing a significant double-walled carbon nanotube population of 24%.
  • Yukihiko Matsumura; Takuya Kokabu; Shuhei Inoue; Tawatchai Charinpanitkul; Sanchai Kuboon
    Journal of the Japan Petroleum Institute 61 3 199 - 204 2018年 [査読有り]
     
    Single-walled carbon nanotubes (SWCNTs) were employed to obtain glucose from lignocellulose effectively via hydrothermal pretreatment. Hydrothermal pretreatment of eucalyptus and cellulose was conducted with and without SWCNT catalysts. SWCNT catalysts modified via oxidation and/or acid treatment were also applied. Oxidation treatment was conducted in the air at 500 °C for 30 min and acid treatment was conducted in the 96 % sulfuric acid for 18 h. Hydrothermal pretreatment was conducted using an 84 mL autoclave by heating samples that contained 0.6 g of cellulose to 200 °C with a heating rate of 4 °C/min and then cooling down at once. The initial SWCNTs were basic, and oxidation resulted in increased basicity. Acid treatment successfully increased the acid site density of the SWCNTs. The glucose yield increased with acid site density, showing the effectiveness of the acid-treated SWCNTs.
  • Shuhei Inoue; Takuya Kokabu; Yukihiko Matsumura
    AIP Advances 8 1 2018年01月 [査読有り]
     
    We studied physical and chemical adsorption on carbon nanotube surfaces and measured the effect of adsorption on their electric conductance. The increase in capacitance at the carbon nanotube interface (due to physisorption) disturbed carrier transport, while chemisorption induced charge transfer and resulted in an increase or decrease in the electric conductance. The principle of carrier transport in carbon nanotube films could be clearly explained by applying a fluctuation-induced tunneling model. Our model proved that the surface coverage ratio and the electric conductance change ratio are closely correlated.
  • Yoshihiro Tomita; Shuhei Inoue; Yukihiko Matsumura
    Chemical Physics Letters 691 351 - 354 2018年01月 [査読有り]
     
    Application of carbon nanotube (CNT) film as a gas sensor is highly desired. Transient behavior of molecular adsorption provides adsorption and desorption constants however, to date, few researchers have investigated it. Here, we focused on the transient behavior of electric conductance of the CNT film during adsorption. Adsorption of polar molecules showed predicable behavior, but non-polar molecules showed a sudden change of electric conductance that indicated excess adsorption. We analyzed the process based on Langmuir adsorption, and adsorption and desorption constants, which are considered to be physical properties however, these parameters did not show good agreement for the same film.
  • Pattasuda Duangkaew; Shuhei Inoue; Tsunehiro Aki; Yutaka Nakashimada; Yoshiko Okamura; Takahisa Tajima; Yukihiko Matsumura
    ENERGY & FUELS 31 10 10866 - 10873 2017年10月 [査読有り]
     
    In situ mass spectrometry analysis was conducted for the hydrothermal decomposition of mannitol at different temperatures and residence times in a batch reactor. The temperature was varied in the range of 140-220 degrees C, and the residence time was varied between 5 and 20 min. The products of mannitol decomposition included furfural, 5-hydroxymethylfurfural, phenol, formic acid, and levulinic acid. At high temperatures, the mass spectrum showed peaks at m/z 46 and 116 that corresponded to formic acid and levulinic acid, respectively. Conventional high-performance liquid chromatography could not detect these acids. Quantification of these products and the rate constants for the mannitol decomposition network were also obtained. The reaction rate coefficients were determined by fitting the experimental results.
  • Pattasuda Duangkaew; Shuhei Inoue; Tsunehiro Aki; Yutaka Nakashimada; Yoshiko Okamura; Takahisa Tajima; Yukihiko Matsumura
    INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH 56 36 9993 - 9998 2017年09月 [査読有り]
     
    This is the first work that describes the application of mass spectrometry to the real-time observation of liquid products of hydrothermal reactions in a continuous reactor. A real-time mass spectrometric analysis (real-time MS analysis) system was developed and designed to elucidate products of glucose decomposition during the hydrothermal treatment process. This was achieved by connecting a continuous-flow reactor with a quadrupole mass analyzer using custom-built connection fittings. The effects of residence time and temperature of hydrothermal treatment on glucose decomposition products were investigated. The temperatures were between 140 and 220 degrees C, and reaction times were between 5 and 20 min. The real-time MS method investigated the products of glucose decomposition, and cold samples were characterized using high-performance liquid chromatography (HPLC). At 140 degrees C, glucose decomposition is not complete, which was confirmed by a mass spectrum of a glucose standard. At a temperature of 180 degrees C or above, fragmentation peaks of fructose at m/z = 131 and 149, ring compound products like 5-hydroxymethylfurfural (5-HMF) at m/z = 97 and 126, and furfural at m/z = 96 and 67 were obtained. Retro-aldol products like glyceraldehyde and glycolaldehyde were also observed, confirmed by m/z = 90, 72, and 61 and an increasing ion current at m/z = 60, 29, and 31, respectively. No fructose was observed using a conventional HPLC at 200 degrees C for 10 min. The effectiveness of real-time MS analysis is strong, collated with a conventional HPLC method.
  • Hidetaka Takaki; Shuhei Inoue; Yukihiko Matsumura
    CHEMICAL PHYSICS LETTERS 684 113 - 116 2017年09月 [査読有り]
     
    Zinc oxide (ZnO) has recently gained interest in the semiconductor field. Controlling defects can lead to band -gap engineering and this concept was explored for the synthesis of ZnO with various types of defects. In this study, we describe a method to synthesize quasi one-dimensional ZnO using gold nanoparticles as a template, using which we successfully controlled defect types like oxygen vacancies, oxygen interstitials, and zinc interstitials. Because the rate determination was the generation of Zn, it will be possible to synthesize ZnO with only zinc interstitials by independent supply of CO and O-2. (C) 2017 Elsevier B.V. All rights reserved.
  • Takuya Kokabu; Kengo Takashima; Shuhei Inoue; Yukihiko Matsumura; Takahiro Yamamoto
    JOURNAL OF APPLIED PHYSICS 122 1 2017年07月 [査読有り]
     
    The electric conductance of carbon-nanotube (CNT) films is affected by gas adsorption. Previous studies have shown that the adsorption of gas molecules on the CNT/CNT interface is the key to the changing CNT-film conductance. However, it is still unclear how the gas molecules affect the electric conduction of the CNT/CNT interface or its electron transport properties. We present here a study on the effects of gas-molecule adsorption on the CNT/CNT interface using a fluctuation-induced tunneling (FIT) model of the CNT-film electrical conduction. We demonstrated that the CNT-film conduction follows the FIT model, and the subsequently estimated electrostatic potential between the CNT/CNT interfaces was in good agreement with estimates from density functional theory simulations. Since the FIT model treats the CNT/CNT interface as a parallel-plate capacitor, we propose a modified FIT model that accounts for the change in the dielectric constant at the CNT/CNT interface due to the adsorption of gas molecules. This model well explained the electric-conductance change of the CNT film with respect to the gas pressure. Finally, we found that the adsorbed gas molecules affected the local dielectric constant at the CNT/CNT interface. Published by AIP Publishing.
  • Obie Farobie; Poomkawee Changkiendee; Shuhei Inoue; Takahito Inoue; Yoshifumi Kawai; Takashi Noguchi; Hiroaki Tanigawa; Yukihiko Matsumura
    INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH 56 22 6401 - 6407 2017年06月 [査読有り]
     
    We herein report the effect of the feedstock heating rate on the supercritical water gasification of a glucose/guaiacol mixture. In the study, glucose was employed as a model compound for cellulose and guaiacol was employed as a model compound for lignin. A mixture of glucose (0.34 wt %) and guaiacol (0.16 wt %) was fed into a laboratory-scale continuous reactor at 600 degrees C and 25 MPa through a preheater, where the feedstock heating rate could be controlled. Feedstock flow rates of 1 and 2 g/min were employed along with preheaters of three different lengths (i.e., 0.45, 0.9, and 1.8 m). We found that longer preheaters resulted in slower heating rates at the same feedstock flow rate. Studies into the effect of the feedstock heating rate on the gasification efficiency indicated that a high heating rate enhanced the carbon gasification efficiency even for a glucose/guaiacol mixture. However, when the heating rate reached similar to 25 K/s, a decrease in the carbon gasification efficiency was observed. This may be due to glucose and guaiacol interacting in a manner similar to that of cellulose and lignin. Finally, the preheater length had no apparent effect on the product gas composition
  • Yuna Yamamoto; Shuhei Inoue; Yukihiko Matsumura
    DIAMOND AND RELATED MATERIALS 75 1 - 5 2017年05月 [査読有り]
     
    We have studied the thermal catalytic decomposition of different typical carbon sources and an unsuitable carbon source in order to gain insight into the chemical vapor deposition of carbon nanotubes. The suitable sources decomposed into Cl and C2 hydrocarbons and their radicals. In contrast, the unsuitable source did not afford hydrocarbons. In this study, pure methane and ethylene pyrolysis resulted in little amounts of Cl and C2 radicals, and so an excess of hydrogen was required to shift the equilibrium reaction between C1 and C2. (C) 2016 Elsevier B.V. All rights reserved.
  • Pattasuda Duangkaew; Shuhei Inoue; Tsunehiro Aki; Yutaka Nakashimada; Yoshiko Okamura; Takahisa Tajima; Yukihiko Matsumura
    KOREAN JOURNAL OF CHEMICAL ENGINEERING 34 5 1524 - 1530 2017年05月 [査読有り]
     
    We designed an in situ mass spectrometry (in situ MS) analysis method and developed to identify the products of glucose decomposition under hydrothermal condition for the first time. The in situ MS analysis was performed by coupling a tubular batch reactor with a quadrupole mass analyzer via custom-built connection fittings. The products of glucose decomposition were investigated by in situ MS, mass spectrometry of cold effluent, and high-performance liquid chromatography (HPLC) analysis of cold effluent and the results were compared. At 140 A degrees C, in situ MS and mass spectrometry of cold effluent showed that the decomposition of glucose does not proceed; this was confirmed by comparison with the mass spectral database for glucose. At 180 A degrees C or higher, a clear base fragmentation peak of 5-hydroxymethylfurfural (5-HMF) at position m/z 97 and that of furfural at m/z 96, formic acid (m/z=46) and levulinic acid (m/z=116) were observed by mass spectrometry. No levulinic acid or furfural was observed through conventional HPLC analysis under any condition; only glucose, formic acid, and 5-HMF could be detected. The effectiveness of in situ MS analysis is clear, compared to mass spectrometry analysis of cold effluent and HPLC analysis.
  • Pattasuda Duangkaew; Shuhei Inoue; Tsunehiro Aki; Yutaka Nakashimada; Yoshiko Okamura; Takahisa Tajima; Yukihiko Matsumura
    JOURNAL OF THE JAPAN PETROLEUM INSTITUTE 60 2 101 - 109 2017年03月 [査読有り]
     
    Quantitative in-situ analysis by mass spectroscopic (MS) method was developed and designed in order to elucidate the decomposition kinetics of glucose under hydrothermal conditions. Briefly, the proposed methodology employed a quadrupole mass analyzer coupled with a tubular batch reactor via custom-built connection fittings. At first, the hydrothermal treatment of glucose was conducted at temperatures ranging from 140 to 220 C-omicron with reaction times between 2.5 min and 20 min. Liquid product obtained after the hydrothermal process was quantitatively analyzed with a mass analyzer and a high-performance liquid chromatography (HPLC) analyzer. The in-situ MS analysis revealed that the decomposition rate of glucose was enhanced at higher temperatures. The results also showed the presence of 5-hydroxymethylfurfural and other low-molecular-weight acids whose concentrations increased when the temperature increased to 180 C-omicron and higher. A reaction pathway of glucose was developed, and the reaction rate constants were determined assuming first-order reactions.
  • Yenchen Lin; Shuhei Inoue; Yukihiko Matsumura; Jyh-Chen Chen
    AIP ADVANCES 7 1 2017年01月 [査読有り]
     
    Among several methods to obtain white light in light emitting diodes (LEDs), mixing blue light with yellow light excited by blue light is the most effective and economical method. However, the quality of white light achieved by this method is poor, making it essential to develop high-quality yellow phosphors. In this study, we synthesized yellow phosphors with broad spectral width by the sol-gel method and studied the effect of various synthetic conditions on their photoluminescence spectra. Consequently, we optimized synthesis conditions for a series of yellow phosphors and found that excess europium doping caused quenching and reduced the quantum yield. (C) 2017 Author(s).
  • Takuya Kokabu; Shuhei Inoue; Yukihiko Matsumura
    AIP ADVANCES 6 11 2016年11月 [査読有り]
     
    Gas sensors based on carbon nanotube (CNT) films have attracted attention owing to their low power consumption. For further development of these sensors, we need to understand the surface interaction of the films with gas molecules. In our previous research, we investigated the influence of water molecules on the electrical conductance of multi-walled CNT films and explained this phenomenon using a two-layer adsorption model. This work motivated us to measure the adsorption energy of CNT-H2O. In this study, we focused on the first-layer adsorption and investigated the sheet resistance to water vapor pressure at various temperatures using the transmission line method (TLM). The results were fitted to Langmuir adsorption model and the adsorption equilibrium constant was determined. The temperature dependence of the sheet resistance followed a model of fluctuation induced tunneling (FIT), in which the energy barrier at the CNT junction is regarded as the main factor influencing the electrical conductance of the CNT film. The sheet resistance and equilibrium constant decreased as temperature increased. This result was consistent with the adsorption phenomenon. Finally, the adsorption energy was determined to be 0.22-0.31 eV, which is larger than the previously calculated value. It was also reported that the adsorption energy of the gas molecules in the interstitial site between two carbon nanotubes was larger than that on the CNT surface. These results indicate that the CNT junction plays a key role in the detection of gas molecules. (C) 2016 Author(s).
  • Takuya Kokabu; Shuhei Inoue; Yukihiko Matsumura
    CHEMICAL PHYSICS LETTERS 654 9 - 12 2016年06月 [査読有り]
     
    We investigated the influence of water adsorption on a CNT thin film. When we assumed that the magnitude of the change in electrical resistance was correlated with the surface coverage of the adsorbed molecules, this phenomenon could be explained by two-layer adsorption. The first layer was expressed by Langmuir adsorption and that on the second layer was expressed by Fowler-Guggenheim adsorption, which was derived by Bragg-Williams approximation and involved a lateral molecular interaction. The adsorption energy estimated by this assumption was on the same order as derived by DFT calculation. (C) 2016 Elsevier B.V. All rights reserved.
  • Shuhei Inoue; Takahiro Kawamoto; Yukihiko Matsumura; Kentaro Tomita; Kiichiro Uchino; Keiji Takata; Hiroshi Kajiyama
    AIP ADVANCES 6 5 2016年05月 [査読有り]
     
    Photochromic nanoparticles of zinc-silicon oxide were synthesized using plasma enhanced chemical vapor deposition. These particles turned black upon irradiating with ultraviolet light. We investigated this phenomenon using density functional theory calculations. Silicon inclusions create trap levels and oxygen defects that reduce the ionization potential of ZnO. This forms a quantum potential between ZnO and zinc-silicon oxide, and the excited electron is stable. Because oxygen defects also increase the bond overlap population between the zinc atoms in a ZnO crystal, they introduce further defects and help in the formation of quantum potentials. Growth of a perfect crystal of ZnO prevents the formation of oxygen defects, which is not desirable for photochromism. (C) 2016 Author(s).
  • Soichi Hirota; Shuhei Inoue; Takahito Inoue; Yoshifumi Kawai; Yasutaka Wada; Takashi Noguchi; Yukihiko Matsumura
    KOREAN JOURNAL OF CHEMICAL ENGINEERING 33 4 1261 - 1266 2016年04月 [査読有り]
     
    Supercritical water gasification (SCWG) has attracted attention as a technology for utilizing wet biomass. We used a fluidized bed of alumina particles to prevent blockage of a SCWG reactor. A glucose solution was heated in the reactor with and without fluidized alumina particles. In the absence of alumina particles, char particles formed homogeneously in the reactor, but the use of a fluidized bed resulted in accumulation of char particles at the reactor's exit rather than inside the reactor. Therefore, the fluidized bed was effective at preventing blockage of the reactor. However, the alumina particles did not remove deposits from the reactor's walls. Instead, the fluidized bed caused larger char particles to form, preventing their adhesion to the reactor's wall.
  • Yosuke Ohga; Shuhei Inoue; Yukihiko Matsumura
    CHEMICAL PHYSICS LETTERS 639 261 - 265 2015年10月 [査読有り]
     
    Using a quadrupole mass spectrometer we measured the activation energy of ethanol decomposition with various catalysts. In order to quantitatively evaluate the catalysts we subtracted their effect from that of the catalyst-free pyrolysis. As a result we derived the activation energies using iron, cobalt, nickel, and molybdenum catalysts. These metals are typical catalysts in carbon nanotube synthesis, with two of them usually mixed empirically. This empirical preparation and use of catalysts is consistent with our results. Among these catalysts, iron reduced the activation energy most. Conversely, cobalt achieved a reduction of only 0.3 eV compared to the catalyst-free reaction. (C) 2015 Elsevier B.V. All rights reserved.
  • Kazuki Nishi; Shuhei Inoue; Yukihiko Matsumura
    CHEMICAL PHYSICS LETTERS 634 194 - 197 2015年08月 [査読有り]
     
    In order to evaluate the free energy associated with supplying an additional carbon atom to a catalyst cluster, we performed umbrella sampling and used the weighted histogram analysis in our classical molecular dynamic simulation. We assumed a one-dimensional reaction coordinate and derived the free energy. The derived free energy distribution was consistent with the observed phenomena and we found a reaction barrier of 0.6 eV near the cluster surface. Beyond the reaction barrier, the free energy increased with increasing density of the carbon atoms, and this indicated that the saturation started from the cluster center. (C) 2015 Elsevier B.V. All rights reserved.
  • Takuya Kokabu; Shuhei Inoue; Yukihiko Matsumura
    CHEMICAL PHYSICS LETTERS 628 81 - 84 2015年05月 [査読有り]
     
    Carbon nanotube gas sensor does not require heat for detecting gas species unlike present semiconductor type; hence, it is expected to be commercially available. The detecting mechanisms are explained by both charge transfer and Schottky barrier, but its detail such as contribution of polar molecule and charge variation are not clear. In this study, we examined as-grown vertically aligned single-walled and dispersed multi-walled carbon nanotube as sensors without any micro/nanofabrication for realizing simple gas sensor. Both film showed obvious response to the air and, their detecting principle is explained only by charge transfer between carbon nanotube and absorbed gas molecules. (C) 2015 Elsevier BY. All rights reserved.
  • Teerameth Janjarasskul; Seung-Gyu Lee; Shuhei Inoue; Yukihiko Matsumura; Tawatchai Charinpanitkul
    JOURNAL OF THERMAL SCIENCE AND TECHNOLOGY 10 1 2015年 [査読有り]
     
    The low heat conductivity of the packed bed is a key issue in thermal engineering fields. It is also one of the dominant factors behind realizing a fuel cell vehicle society because it prevents quick recharging of hydrogen due to its exothermic reaction. In this study, we examined the enhancement in the effective thermal conductivity of the packed bed with the use of single-walled carbon nanotubes, which were directly synthesized on the particles of the packed bed. We employed two kinds of particles for the packed bed; one was alumina of 10 jam in diameter, which is comparable to usually used in actual system and the other was zeolite, which was used for synthesizing high quality carbon nanotube. Consequently, 10 vol. % of carbon nanotube enhanced three times of effective thermal conductivity.
  • Shuhei Inoue; Daisuke Nakahara; Yukihiko Matsumura
    CHEMICAL PHYSICS LETTERS 616 217 - 221 2014年11月 [査読有り]
     
    The precursor and its formation kinetics were investigated using isotopes of ethanol with supporting calculations using GAUSSIAN09. The major products were CH2OH, C2H5, and ethylene. At temperatures exceeding 900 degrees C, carbon monoxide was also formed, but as less than 20% of the total product. The synthesis of CH2OH and C2H5 were reasonably explained by theoretical calculations; however, the synthesis of ethylene could not be explained by examination of the activation energy. However, if we assumed a specific dissociation order, the activation energy decreased owing to the dissociation of a hydroxyl radical, which was consistent with experimental results. (C) 2014 Elsevier B.V. All rights reserved.
  • Gasification characteristics of amino acids in supercritical water
    Thachanan SAMANMULYA; Shuhei INOUE; Takahito INOUE; Yoshifumi KAWAI; Haruhito KUBOTA; Hiroto MUNETSUNA; Takashi NOGUCHI; Yukihiko MATSUMURA
    J. Jpn. Inst. Energy 93 9 936 - 943 2014年09月 [査読有り]
  • Thachanan Samanmulya; Shuhei Inoue; Takahito Inoue; Yoshifumi Kawai; Haruhito Kubota; Hiroto Munetsuna; Takashi Noguchi; Yukihiko Matsumura
    JOURNAL OF THE JAPAN PETROLEUM INSTITUTE 57 5 225 - 229 2014年09月 [査読有り]
     
    Alanine solution (1.0-3.0 wt%) was gasified in supercritical water using a tubular reactor at a temperature of 500 to 650 degrees C and a pressure of 25 MPa for a residence time of 86-119 s and compared the gasification characteristic with our previous work, glycine. The identification and quantification of gaseous products were conducted by gas chromatography (GC) and the total organic carbon (TOC) in the aqueous phase was also determined. The carbon gasification efficiency of alanine rose with increasing reaction temperature and the gasification rate followed first order kinetics. It was well expressed with the Arrhenius equation. The gasification rate of alanine was identical to that of glycine. The effect of the methyl group in alanine is the production of methane and the dilution of nitrogen so that the alkaline effect is suppressed. The former explains the higher methane yield, and the latter results in a high carbon monoxide yield.
  • Kazuki Nishi; Shuhei Inoue; Yukihiko Matsumura
    CHEMICAL PHYSICS LETTERS 604 1 - 4 2014年06月 [査読有り]
     
    Nucleation of carbon nanotubes is considered to start with the supersaturation of carbon atoms dissolved in a catalyst. In chemical vapor deposition synthesis, it is believed that condensation of the source gas terminates the growth. However, some experimental studies have suggested that termination is primarily affected by catalyst behavior. We modified the potential functions and observed the behavior of carbon-iron mixed nanoparticles by a molecular dynamics method and found that the iron fraction melted at the equivalent temperature of growth termination. Thus, we concluded that the catalyst fusion prevented nucleation that would normally occur as a consequence of solution supersaturation. (C) 2014 Elsevier B.V. All rights reserved.
  • Kazuki Nishi; Shuhei Inoue; Yukihiko Matsumura
    Engineering Journal 17 5 19 - 27 2013年12月 [査読有り]
     
    We have focused on the growth process of metal and carbon mixed clusters that are precursors for carbon nanotubes. The molecular dynamics method using the Brenner potential was employed for modeling carbon–carbon interactions as well as carbon–iron interactions. As for carbon–iron interactions, the parameters were derived using DFT calculation. The Finnis–Sinclair potential was employed for irons. In order to observe the deposition process of carbon atoms, we adjusted the potential parameters to reproduce the bulk melting points of graphite, iron, and cementite, which was a model material of iron–carbon composite. We observed the initial growth process by preparing iron–carbon mixed clusters (approximately 200 iron atoms and 70 carbon atoms) as precursor clusters. Additional carbon atoms were then gradually supplied to this mixture at 1000 K and 1200 K. Consequently, the graphite structure was formed on the mixture surface, but at some phases, the cap structure was observed at 1200 K.
  • Heat Transfer Characteristics of Activated Carbon Suspended Slurry Near the Critical Point of Water
    Horiguchi, Naoki; Inoue, Shuhei; Kawai Yoshifumi; Noguchi, Takashi; Minowa, Tomoaki; Wada, Yasutaka; Matsumura, Yukihiko
    2013年03月 [査読有り]
  • Yukihiko Matsumura; Shotaro Hara; Kohei Kaminaka; Yasunao Yamashita; Takuya Yoshida; Shuhei Inoue; Yoshifumi Kawai; Tomoaki Minowa; Takashi Noguchi; Yoshihisa Shimizu
    JOURNAL OF THE JAPAN PETROLEUM INSTITUTE 56 1 1 - 10 2013年01月 [査読有り]
     
    Supercritical water gasification is expected to be an effective gasification process for wet biomass, but its reaction kinetics has not been elucidated for actual biomass feedstocks. In this study, seven biomass species are gasified in a supercritical water gasification reactor with and without use of a suspended activated carbon catalyst, and the overall gasification rates are determined. The feedstocks can be classified into three groups depending on the gasification characteristics. Representative gasification-rate parameters are presented. The homogeneous reaction had a pre-exponential factor of 50.0 s(-1) and an activation energy of 67.9 kJ/mol. The heterogeneous reaction for feedstocks with high cellulose content had a pre-exponential factor of 4.87 x 10(9) s(-1) and an activation energy of 161 kJ/mol, while, feedstocks with low cellulose content had a pre-exponential factor of 1.91 x 10(4) s(-1) and an activation energy of 84.2 kJ/mol.
  • B. A. Cola; H. Daiguji; C. Dames; N. Fang; K. Fushinobu; S. Inoue; G. Kikugawa; M. Kohno; S. Kumar; D. Y. Li; J. R. Lukes; J. A. Malen; A. J. H. McGaughey; O. Nakabeppu; K. Pipe; P. Reddy; S. Shen; L. Shi; M. Shibahara; Y. Taguchi; K. Takahashi; T. Yamamoto; T. Zolotoukhina
    NANOSCALE AND MICROSCALE THERMOPHYSICAL ENGINEERING 17 1 25 - 49 2013年01月 [査読有り]
     
    The seventh U.S.Japan Joint Seminar on Nanoscale Transport Phenomena was held in Shima, Japan, from December 11 to 14, 2011. The goals of this joint seminar were to provide a critical assessment of the state of the art and future directions in the field of nanoscale transport phenomena and energy conversion processes, to foster U.S.Japan collaborations, and to provide international exposure to a new generation of scientists in this field. Issues discussed in the joint seminar were organized in 10 topical sessions, including (1) nanoscale thermophysical measurements; (2) optical characterization; (3) thermal and molecular transport; (4) phonon transport modeling; (5) energy storage and conversion; (6) nanoscale fluidics and phase change phenomena; (7) biological and organic systems; (8) interfacial thermal transport; (9) novel thermoelectric and thermal management materials; and (10) nanocarbon materials and devices. In addition to these topical sessions, the joint seminar featured an opening plenary session and a closing plenary session as well as an expert panel, where leading experts provided critical assessment of the past progress and addressed future directions in the field. In addition, an evening poster session provided opportunities for graduate and postdoc students to present their latest research results. About 35 researchers from Japan and 31 researchers from the United States participated in the meeting. The meeting was organized by S. Maruyama, K. Fushinobu, L. Shi, and J. Lukes together with about 20 other participants who served as session chairs. Summaries of different sessions of the seminar were prepared by the session and conference chairs and are collected into this report.
  • Takashi Tomie; Shuhei Inoue; Yushi Iba; Yukihiko Matsumura
    CHEMICAL PHYSICS LETTERS 536 104 - 108 2012年05月 [査読有り]
     
    In situ mass spectroscopic analysis was carried out to clarify the growth mechanism of single-walled carbon nanotube grown by alcohol catalytic chemical vapor deposition. When catalysts were used, pyrolysis could be accomplished at a temperature of 600 degrees C; without the use of catalysts, successful pyrolysis required a temperature of more than 800 degrees C. Ethylene and acetylene are important products for the synthesis of carbon nanotubes, and fusion of the metal catalyst is the cause of failure of synthesis at high temperatures. This fact indicates that the degradation and polymerization of ethanol are not the cause of the failure of synthesis. (C) 2012 Elsevier B. V. All rights reserved.
  • Takashi Tomie; Shuhei Inoue; Yukihiko Matsumura
    CHEMICAL PHYSICS LETTERS 533 56 - 59 2012年04月 [査読有り]
     
    To elucidate the growth mechanisms of carbon nanotubes by chemical vapor deposition, we performed in situ mass spectroscopy for methane CVD. Methane is considered stable at temperature below 1000 degrees C; however, using appropriate catalysts, it can be decomposed. In previous studies, acetylene and ethane were thought to be key intermediates in the synthesis of carbon nanotubes, but in this study, ethylene was found to be the key building block. The yield of ethylene was low but this is consistent with the fact that the production rate of carbon nanotubes by methane CVD was lower than that by ethylene CVD synthesis. (C) 2012 Elsevier B. V. All rights reserved.
  • Shuhei Inoue; Yushi Iba; Yukihiko Matsumura
    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 37 2 1836 - 1841 2012年01月 [査読有り]
     
    Low heat conductivity restricts the rate of hydrogen absorption into a metal hydride, and this leads to a mismatch of the required absorption rate. The use of fin systems is standard in such cases, and the use of several different materials has been attempted. This includes high thermal conductivity carbon brushes and carbon nanotube. Unfortunately, such efforts have not been effective because the boundary thermal resistance has not been addressed. In this study, we focused on the direct synthesis of a single-walled carbon nanotube (SWCNT), which has high thermal conductivity, on particles in a packed bed, for reducing boundary thermal resistance and estimated effective thermal conductivity. Referring to Raman spectra, we succeeded in growing SWCNT on a metal hydride and effective thermal conductivity was estimated as a function of the filling ratios of the metal hydride and the SWCNT. Consequently, the effective thermal conductivity can satisfy the required value. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
  • Takashi NOGUCHI; Yoji NODA; Yoshihiko YAMASAKI; Shuhei INOUE; Yoshifumi KAWAI; Yoshihisa SHIMIZU; Tomoaki MINOWA; Yukihiko MATSUMURA
    Journal of the Japan Institute of Energy 90 9 874 - 880 2011年 [査読有り]
  • 野口 琢史; 野田 洋二; 山崎 慶彦; 井上 修平; 松村 幸彦; 川井 良文; 清水 嘉久; 美濃輪 智朗
    日本エネルギー学会誌 90 12 1165 - 1170 2011年 [査読有り]
     
    The rheological characterisitcs of biomass slurry was determined from the pressure drop under high temperature and high pressure, using chicken manure. The dependence of the pressure drop on the flow rate was used to distinguish laminar and turbulent flow. The n-th order model was employed, and parameters in the model were determined to reproduce the experimental results. Surprisingly, the flow was well expressed with the Newtonian model where n=1, which contradicts with the previous study using the rotating viscometer. The difference in the sheer rate is expected to be the cause of this difference. The apparent viscosity reduced with temperature rise, and agrees with that of water above 300 C for the slurry employed here. The methodology employed here is simple, and can be employed to determine the rheological characteristics of various slurries.
  • Shuhei Inoue; Yukihiko Matsumura
    JOURNAL OF THERMAL SCIENCE AND TECHNOLOGY 6 2 256 - 267 2011年 [査読有り]
     
    Carbon nanotubes possess outstanding properties such as high thermal conductivity, ultra-high physical strength, and durability. With regard to applications, a single-walled carbon nanotube (SWCNT) is a great candidate for a new material. Furthermore, a metal-coated SWCNT has been experimentally developed and its properties have attracted much attention. In this study, we simulated the deposition process of metal species onto an SWCNT to estimate its resulting physical strength and thermal diffusivity using a classical molecular dynamics method. Consequently, we found that the physical strength of the metal-coated SWCNT was similar to that of an uncoated SWCNT, whereas its thermal diffusivity showed a decrease of 90%.
  • Masamichi Kohno; Teppei Kawahara; Masahiro Tomoda; Yasuyuki Takata; Shuhei Inoue; Shinzo Suzuki; Shigeo Maruyama
    JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY 25 1 11 - 15 2011年01月 [査読有り]
     
    SWNTs were synthesized by laser-vaporized CCVD (catalytic chemical vapor deposition). The diameter distributions and the abundance of SWNTs synthesized at different temperatures and using different catalysts were investigated by Raman spectroscopy. Further, this technique was compared with other synthesis techniques (laser-oven and conventional-alcohol CCVD), and C(60) was synthesized simultaneously as a byproduct only using the laser-oven technique. With increasing synthesis temperature, the diameter distribution shifted towards larger diameters, and the G/D ratio became larger as the synthesis temperature increased to 1000 degrees C. Ni, Co, and Fe played a catalytic role, though Fe was less effective under our experimental conditions. The diameter distribution of SWNTs synthesized with the Fe catalyst was shifted to smaller values compared to those synthesized with Ni or Co catalysts.
  • Takashi Tomie; Shuhei Inoue; Masamichi Kohno; Yukihiko Matsumura
    DIAMOND AND RELATED MATERIALS 19 11 1401 - 1404 2010年11月 [査読有り]
     
    Chemical vapor deposition has become a standard process for synthesizing carbon nanotubes. Since the successful use of chemical vapor deposition for the first time, much effort has been expended into exploring various carbon sources that can be used to synthesize carbon nanotubes, such as methane, ethane, and ethanol. However, whole perspectives for suitable carbon sources have not been clear. In this study, we performed experiments in order to determine that the appropriate C-H-O components ratio in raw materials can be used to synthesize carbon nanotubes. We also examined a variety of raw materials in our newly developed round-trip-type vacuum furnace in order to determine whether they could be used to synthesize a carbon nanotube. We used Raman spectroscopy to identify the developed carbon nanotube, and we plotted the component ratios of effective and ineffective materials on a C-H-O ternary diagram: in this diagram, the growth region became highly apparent. It should be noted that for the growth of the carbon nanotube, this region should satisfy the equation O<C<(H + O) in molar ratio. Furthermore, it was observed that adjusting the component ratios by mixing raw materials did not cause an inconsistency in the growth region. (C) 2010 Elsevier B.V. All rights reserved.
  • Shuhei Inoue; Yukihiko Matsumura
    CHEMICAL PHYSICS LETTERS 495 1-3 80 - 83 2010年07月 [査読有り]
     
    Recently a functionalized single-walled carbon nanotube (SWCNT) that is modified by metal atoms was experimentally developed. Single-walled carbon nanotube is known to exhibit exceptional thermal conductivity; however, there is no report about a functionalized SWCNT. In this study, thermal diffusivity of metal-coated SWCNT was derived using molecular dynamics. Consequently, thermal diffusivity exhibited 10 times smaller than uncoated SWCNT. On the other hand, the heat conduction on the metal layer was observed as the shape of shoulder on the thermal time response and it was found that this contribution was not small for a short-length SWCNT. (C) 2010 Elsevier B.V. All rights reserved.
  • Shuhei Inoue; Kazuya Nomura; Yukihiko Matsumura
    MICROELECTRONICS JOURNAL 40 4-5 692 - 696 2009年04月 [査読有り]
     
    It is important to understand catalytic reactions involved in synthesizing carbon nanotubes. Usually, catalysts are used with supporters for better stability and influences of supporters on catalysis is negligible; however, catalysts used for synthesizing single-walled carbon nanotubes are too small to neglect their influence. Here, we experimentally investigated efficiencies of commonly used catalyst supporters such as magnesium oxide, zeolite, and aluminum oxide when they were combined with iron-cobalt,, which is a typical catalyst. It was observed that zeolite-supported catalysts could synthesize single-walled carbon nanotubes, while the others could not. Cluster molecular orbital calculations showed that electronic states of catalysts supported by MgO in the boundary layer between catalysts and supporters were restricted due to covalent bonding between cobalt and magnesium. Density functional theory calculations indicated that catalysts on zeolite had enough electrical orbital near Fermi level and they widely spread over catalysts surface, but catalysts on MgO did not. This characteristic can affect catalytic activities. (C) 2008 Elsevier Ltd. All rights reserved.
  • Shuhei Inoue; Yukihiko Matsumura
    CHEMICAL PHYSICS LETTERS 469 1-3 125 - 129 2009年02月 [査読有り]
     
    The physical strength of a metal-coated single-walled carbon nanotube (SWCNT) is derived in terms of a stress-strain curve by molecular dynamics simulation. The breaking stress of a metal-coated SWCNT was lower than that of an uncoated SWCNT; however, the force constant increased by 17%, which can be attributed to the effect of the metal coating on the SWNCT. With regard to the rupture phenomena, it was observed that the uncoated SWCNT yielded more easily than the metal-coated SWCNT at the yield point. The rupture phenomenon was initiated by a local distortion of the metal atoms of the SWCNT. (C) 2009 Elsevier B. V. All rights reserved.
  • Shuhei Inoue; Yukihiko Matsumura
    CARBON 46 15 2046 - 2052 2008年12月 [査読有り]
     
    Behaviors of nickel and gold clusters deposited onto a vertically aligned single-walled carbon nanotube film (VA-SWCNT) were investigated by molecular dynamics simulation methods. Brenner potential was applied for carbon-carbon, and bond-order potential was applied for metal-metal and carbon-metal interactions. Their parameters of gold-gold and carbon-gold were derived by density functional theory calculations. After metal clusters were fully annealed, they were deposited onto the flat nanotube surface with small evaporation energy. Nickel clusters spread over the surface; on the other hand, the gold clusters sometimes formed a grain-like structure, especially when they formed a large cluster before arriving at the surface. When another CNT was placed on the vertically aligned surface, nickel clusters spread and formed a smooth surface, as in the case of a VA-SWCNT film; however, gold clusters could not spread but formed a grain-like structure. This result is in good agreement with the experimental and indicates the mechanism for forming a grain-like structure on a VA-SWCNT. To avoid the formation of a grain-like structure on the surface of a SWCNT, the deposition should be carried out under a high vacuum condition and at a low deposition rate for preventing clustering as it obstructs formation of a flat surface. (C) 2008 Elsevier Ltd. All rights reserved.
  • Shuhei Inoue; Yoshihiro Kikuchi; Yukihiko Matsurnura
    DIAMOND AND RELATED MATERIALS 17 11 1888 - 1890 2008年11月 [査読有り]
     
    A new effective catalysts combination of iron - nickel for alcohol CVD technique was found. This catalyst catalyzed well as well as the typical catalyst of iron - cobalt catalysts, but gave a different diameter distribution. Calculating their electrical density of states under the assumption of their solid lattice structures, the result was fairly consistent with experimental results. The number of electrical states near Fermi level that is considered to be important for catalytic reaction is enough and the DOS of iron - nickel catalyst was quite similar to that of cobalt unlike manganese - copper catalyst. Consequently, a blend of catalysts that has a similar DOS to cobalt and has enough states near the Fermi level can be a good catalyst for alcohol CVD. (C) 2008 Elsevier B.V. All rights reserved.
  • Shuhei Inoue; Yukihiko Matsumura
    CHEMICAL PHYSICS LETTERS 464 4-6 160 - 165 2008年10月 [査読有り]
     
    Behaviors of various metals coating on single-walled carbon nanotubes are simulated by molecular dynamics. Some of the potential parameter sets are derived by DFT calculations. The results indicate that each metal species can be smoothly coated on an isolated carbon nanotube, depending on the coating condition; however, continuous coating may not always be possible. The equilibrium position on the carbon nanotube is fixed; therefore, the coating is discontinuous for a large sized atom to reduce the distortion. The diffusion rate of the metal atoms is expressed in terms of the ratios of the binding energies of metal-metal and metal-carbon bonds. (C) 2008 Elsevier B.V. All rights reserved.
  • Shuhei Inoue; Shigeo Maruyama
    JAPANESE JOURNAL OF APPLIED PHYSICS 47 4 1931 - 1936 2008年04月 [査読有り]
     
    The chemical reactions of transition metal clusters in the gas phase have aroused considerable scientific interest and are also of critical scientific importance. For example, these reactions are involved in the synthesis of single-waited carbon nanotubes, which are considered ideal materials because of their outstanding properties. Alcohol catalytic chemical vapor deposition (ACCVD) is one of the best synthetic processes for carbon nanotubes (CNTs); however, even the initial growth mechanism is still unclear, unlike those of other synthetic processes. In this study, we used a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer to determine the initial reactions of transition metal cluster ions (iron, cobalt, and nickel) that are typically adopted in the alcohol CVD process. Metal clusters with approximately 10-25 atoms each, generated by a pulsed laser ablation system in a supersonic-expansion cluster beam source, were directly carried into the FT-ICR cell. Subsequently, ethanol was introduced into the ICR cell. We observed two different results: one was simple chemisorption observed in the iron cluster and the other was dehydrogenated chemisorption observed in the nickel cluster; however, cobalt clusters exhibited both patterns, and a sequential reaction was observed. Furthermore, the dehydrogenation of ethanol on the cobalt cluster is fully described from isotope-labeled experiments.
  • S Inoue; T Nakajima; Y Kikuchi
    CARBON 44 7 1287 - 1291 2006年06月 [査読有り]
     
    The diameter-controlled synthesis of single-walled carbon nanotubes (SWNTs) has been examined experimentally. The catalysis of the Rh and Pd atoms has been confirmed by blending with Co atoms at 950 degrees C in a furnace, although the Rh/Pd catalyst has not been recorded to act efficiently at this temperature before. Raman spectra indicate that the Rh/Co and Pd/Co catalysts can synthesize narrow-diameter SWNTs more selectively than the Fe/Co and Ni/Co catalysts, which can only synthesize SWNTs with slightly larger diameters. These results suggest that by changing the combination of catalysts, the persistent problem of controlling the diameter of SWNTs can be solved without any expensive setup or complicated techniques. (c) 2005 Elsevier Ltd. All rights reserved.
  • S Inoue; Y Kikuchi
    CHEMICAL PHYSICS LETTERS 410 4-6 209 - 212 2005年07月 [査読有り]
     
    Single-walled carbon nanotubes (SWWs) have been synthesized using the alcohol chemical vapor deposition technique. On comparing the SWNTs synthesized using different catalyst compositions, an obvious fact has been clarified - the diameter of SWNTs is strongly dependent on the sizes of the catalyst particles and metal species. Iron atoms exhibit a strong interaction with carbon atoms and keep their diameters narrow. Cobalt atoms exhibit a poorer interaction than the iron atoms, but work to decompose ethanol. As a result, narrow SWNTs are generated on the iron-rich catalyst. In this Letter, we propose the most probable growth mechanism of the SWNTs. (c) 2005 Elsevier B.V. All rights reserved.
  • S Inoue; T Nakajima; Y Kikuchi
    CHEMICAL PHYSICS LETTERS 406 1-3 184 - 187 2005年04月 [査読有り]
     
    Using alcohol catalytic chemical vapor deposition technique, the relationships among catalyst species, alcohol and synthesis temperature have been investigated in the temperature range from 600 to 1000 degrees C. In this experiment molybdenum-cobalt functions best as a catalyst among the three catalysts (iron-cobalt, Fe/Co; molybdenum-cobalt, Mo/Co; rhodium-palladium, Rh/Pd), for ethanol. A similar temperature dependency has been observed for both Fe/Co and Mo/Co catalysts; however, different chiral indices have been synthesized. In case of methanol, Mo/Co can work less efficiently than Fe/Co. (c) 2005 Elsevier B.V. All rights reserved.
  • 井上修平; 丸山茂夫
    日本機械学会論文集（B編） 71 707 1909 - 1914 2005年 [査読有り]
     
    Chemical reaction of cobalt clusters with ethanol (1CH 3 2CH2OH) has been investigated by using FT-ICR mass spectrometer. Dominant reaction is ethanol chemisorptions but about some size clusters (Con +: 12≤n≤19) complex reactions (involving dehydrogenated chemisorptions) have been observed. By doing isotope experiment (ethanol, ethanol-d, ethanol-d3, ethanol-d6), dissociated two H atoms are specified. This reaction mechanism consists of two steps. At the first step, H atoms are dissociated from methyl (1CH3) and hydroxyl (OH). At the second step, two H atoms are dissociated from methylene (1CH2, 2CH2). On these size clusters hydrogen-deuterium exchange has been observed. This H/D exchange takes place on hydroxyl in case of simple chemisorptions of ethanol, and on methyl in case of dehydrogenated chemisorptions.
  • 河野正道; 井上修平; 丸山茂夫
    日本機械学会論文集（B編） 71 704 1148 - 1154 2005年 [査読有り]
     
    Mass-selected silicon cluster ions were levitated in a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer and monitored during chemisorption reaction with ethylene (C2H4). Through measurements of "time-dependency" of this reaction process, large change of the reactivity depending on the number of absorbed ethylene was observed, in addition to the strong dependency to silicon cluster size. From Si15 + to Si18 + shows a special stability of SixEy + when x + y = 19, such as Si15E4 +. The large decrease in the reactivity of Sin + was observed due to the contamination of hydrogen atom to Sin +. Rate constants for the adsorption of the first C2H4 molecules on Sin + were estimated. The reaction kinetics data suggest that structural isomers are present for all clusters except Si14 + in the size range investigated.
  • 井上 修平; 丸山 茂夫
    日本機械学会論文集（B編） 71 707 1915 - 1920 一般社団法人日本機械学会 2005年 [査読有り]
     
    Chemical reaction of transition metal cluster ions (Fe, Co, Ni) with ethanol was investigated by using the FT-ICR mass spectrometer. Metal clusters with 10-20 atoms were generated by a pulsed laser-vaporization supersonic-expansion cluster beam source directly connected to FT-ICR mass spectrometer. Observed reactions are simple chemisorptions of ethanol and dehydrogenated chemisorptions strongly depending on metal species and cluster size. The reaction of iron clusters show simple chemisorptions and the reaction of nickel clusters show dehydrogenated chemisorptions. However cobalt clusters show both reaction patterns. Thus the reaction patterns change according as periodic table. And the cluster sizes which show the maximum reaction rate also shifted according as periodic table.
  • M Kohno; A Yabe; S Inoue; S Maruyama
    MICROSCALE THERMOPHYSICAL ENGINEERING 7 1 33 - 39 2003年01月 [査読有り]
     
    Metal-carbon binary clusters generated by the laser vaporization of Ni/Co and Ni/Y doped graphite samples used for tire macroscopic laser-oven production of SWNTS were studied. Positive and negative clusters generated by the laser-vaporization supersonic-expansion cluster beam source were directly injected into the FT-ICR (Fourier Transform Ion Cyclotron Resonance) mass spectrometer. Depending on the metal species, the generation efficiency of metal-carbon binary clusters was drastically different. Tire chemical reaction of these clusters with NO gas was used as the probe of the geometrical structure of clusters. The reactivity to NO of these binary clusters was completely different. In case of YCn (n = even, n greater than or equal to 36), chemical reaction of YCn with NO was not observed while pure carbon clusters were reacted. On the other hand, for MCn (M = Ni or Co), the reactivity was much higher than pure carbon clusters. It was speculated that a few Ni or Co atoms attached outside of imperfect carbon cage for Ni/Co doped case and that Y atom was included in tire carbon cage for Ni/Y doped case.
  • Masamichi Kohno; Shuhei Inoue; Shigeo Maruyama
    日本機械学会論文集（B編） 69 684 1886 - 1892 2003年 [査読有り]
     
    Metal-carbon binary clusters are believed to be important precursor clusters both for single-walled carbon nanotubes (SWNTs) and endohedral metallofullerene. Metal-carbon binary clusters (MCn M = La, Ni or Co) and carbon clusters (Cn) were generated with a pulsed laser-vaporization supersonic-expansion cluster beam source directly connected to the FT-ICR (Fourier transform ion cyclotron resonance) mass spectrometer, and chemical reaction of MCn - and Cn - with nitric oxide was studied. Depending on the metal element, the generation efficiency and the reactivity of metal-carbon binary clusters were completely different. LaCn - (n=even, n≥36) was much less reactive to NO than pure carbon clusters, while MCn - (M = Ni or Co) was much more reactive than pure carbon clusters. It was speculated that LaCn - (n=even, n≥36) had a fullerene-like cage structure with a metal atom inside, and that MCn - (M = Ni or Co) had an imperfect cage structure where a metal atom preferentially attached to the imperfect site.
  • Shuhei Inoue; Masamichi Kohno; Shigeo Maruyama
    日本機械学会論文集（B編） 69 684 1879 - 1885 2003年 [査読有り]
     
    Chemical reaction of small silicon cluster ions (Sin +:13, 15 ≤i ni ≤i 29) with nitric oxide was studied by using the FT-ICR (Fourier Transform Ion Cyclotron Resonance) mass spectrometer. Silicon clusters were generated by a pulsed laser-vaporization supersonic-expansion cluster beam source directly connected to the FT-ICR mass spectrometer. Fully thermalized and mass-selected clusters were reacted with NO in the ICR cell. The primary reaction was the exchange of a silicon atom with a nitrogen atom as Sin + + NO → Sin-1N+ + SiO. Then, smaller clusters than Si23N+ (with exceptions for Si16N+ and Si20N+) fragmented to much smaller clusters. It was explained that in general smaller clusters could not survive with the exothermal reaction heat. On the other hand, the magic number clusters of Si16N+ and Si20N+ probably represented the geometrical special stability.
  • M Kohno; S Inoue; R Kojima; S Chiashi; S Maruyama
    PHYSICA B-CONDENSED MATTER 323 1-4 272 - 274 2002年10月 [査読有り]
     
    Metal-carbon binary clusters generated by the laser vaporization of Ni/Co- and Ni/Y-loaded graphite samples used for the macroscopic production of SWNTs were studied. Positive and negative clusters generated by the laser-vaporization supersonic-expansion cluster beam source were directly injected into the FT-ICR mass spectrometer. The chemical reaction of these clusters with NO was used as the probe of the geometrical structure of clusters. It was speculated that a few Ni or Co atoms attached outside of imperfect carbon cage for Ni/Co loaded case, and that Y atom was included in the carbon cage for Ni/Y loaded case. (C) 2002 Elsevier Science B.V. All rights reserved.
  • FT-ICR Study of Chemical Reaction of Silicon Clusters
    Maruyama, Shigeo; Kohno, Masamichi; Inoue, Shuhei
    Thermal Science and Engineering 7 6 69 - 74 1999年 [査読有り]

書籍

  • 熱力学
    松村幸彦; 遠藤琢磨; 笠原次郎; 野村信副; 田之上健一郎; 大澤克之; 小田哲也; 城崎知至; 坪井伸行; 板谷義紀; 井上修平 (担当:分担執筆範囲:14，15章)朝倉書店 2015年09月 ISBN: 9784254237948 200 137-150
  • 多幾山 憲, 須佐 秋生, 尾形 陽一, 松村 幸彦, 難波 愼一, 下栗 大右, 西田 恵哉, 井上 修平, 遠藤 暁, 静間 清 (担当:分担執筆範囲:3.3, 5.2)広島大学出版会 2012年03月 ISBN: 9784903068213 125p
  • Marulanda J. M. (担当:分担執筆範囲:16章)2010年03月 ISBN: 9789533070544

MISC

共同研究・競争的資金等の研究課題

  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2023年06月 -2025年03月 
    代表者 : 井上 修平; 井ノ上 泰輝
  • 直接通電加熱によるバイオマスの超臨界水ガス化のパラダイムシフト
    日本学術振興会：科学研究費助成事業 挑戦的研究(開拓)
    研究期間 : 2022年06月 -2025年03月 
    代表者 : 松村 幸彦; 井上 修平
  • 薄膜界面における光誘起イオン拡散現象の制御と『フォトクロ電池』への展開
    日本学術振興会：科学研究費助成事業(基盤研究(B))
    研究期間 : 2020年 -2022年 
    代表者 : 井上 修平
  • カーボンナノチューブを利用した有機溶剤リーク試験紙の開発
    科学技術振興機構：研究成果展開事業 研究成果最適展開支援プログラム トライアウト
    研究期間 : 2020年11月 -2021年10月 
    代表者 : 井上 修平
  • フォトクロミックナノ粒子による革新的蓄電池の開発
    一般財団法人材料科学技術振興財団：令和元年度研究助成 助成金
    研究期間 : 2020年01月 -2021年03月 
    代表者 : 井上 修平
  • 産学が連携した研究開発成果の展開 研究成果展開事業 研究成果最適展開支援プログラム(A-STEP) 産学共同(育成型)
    研究期間 : 2021年 -2021年 
    代表者 : 井上 修平
     
    ワクチン防免は有効だが開発に時間と費用を要し、変異・未知ウイルス即応できないことから、無差別に駆除できる手法が有効である。ラジカルプラズマは反応性が高く、最適・高効率に生成できれば、空間形状・空間規模に関りなく、無換気で除菌が可能となる。換気に伴う冷暖房エネルギー損失は甚大、強くCO2削減が要求される現状下、ウイルスは人類だけでなく環境への脅威ともなる。本提案では、細い先端を多数持つカーボンナノチューブ紙を電極利用することで放電電圧を大きく下げ、10倍以上のプラズマ生成エネルギー効率を実現する。加え空調機内部での処理法で、エアロゾル感染の阻止、ラジカル放出による施設除菌システムへの展開を可能とする。
  • カーボンナノチューブ界面での電子輸送－ユビキタスガスセンサーへの道－
    日本学術振興会：科学研究費助成事業(挑戦的研究(萌芽))
    研究期間 : 2018年 -2019年 
    代表者 : 井上 修平; 千足昇平; 井ノ上泰輝
  • 文部科学省：科学研究費助成事業(基盤研究(B))
    研究期間 : 2016年 -2018年 
    代表者 : 井上 修平
     
    本研究の目的はバンドギャップ間の光吸収により発電しそのまま蓄電可能な機能をもつ新規なフォトクロミックナノ粒子の蓄電メカニズムを実験的に明らかにすること，熱的不安定性を解決することである．更には界面での電子の移動度を制御する手法を実現することで蓄電池の性能向上と熱電変換素子やキャパシタ開発分野にまで波及する基盤技術を開発することにある．近年スズとマグネシウムの酸化物からなる半導体ナノ粒子が特異な蓄電性を示すことが報告された．この粒子は紫外線照射に誘起されるフォトクロミズム(PC: 光による色の変化)により蓄電性を発現する．しかし蓄電メカニズムが不明であり熱緩和による蓄電性の可逆的消失の原因も分かっていない．本研究ではこれまでの成果により提案したモデルを実験的に検証し計算科学を駆使した材料設計の実現を目指す．
  • ノンレアメタルナノ粒子を利用した革新的蓄電池の機構解明と開発
    東電記念財団：研究助成（基礎研究）
    研究期間 : 2013年 -2016年 
    代表者 : 井上修平
  • 酸化物粒子の光電変換特性に及ぼす結晶性の影響評価
    物質・デバイス領域共同研究拠点：物質・デバイス領域共同研究拠点共同研究課題
    研究期間 : 2015年 -2015年 
    代表者 : 井上修平
  • 文部科学省：科学研究費助成事業(若手研究(A))
    研究期間 : 2013年 -2015年 
    代表者 : 井上 修平
     
    レアアースを用いないマグネシウムと亜鉛の酸化物からなる半導体ナノ粒子が特異な蓄電性を示すことが初めて報告されておりこの粒子は紫外線照射に誘起されるフォトクロミズムにより蓄電性を発現し、金属の密度で電子を蓄電することが確認された。これは10 cm角の基板に25 um堆積させると単三電池に相当する蓄電量である。しかし蓄電メカニズムに関しては不明であり熱緩和による可逆的な蓄電性の消失の原因も分かっていない。これまでの研究から基板上に堆積した粒子は10 nmから数100 nmの大きさであり、気相中ではなく基板上でも凝集による成長したものなど雑多な集合体となっている。このためCVD合成された酸化物半導体膜は局所的にしか蓄電機能を発現しない。CVDによる装置内の熱流体的な不均一場によりたまたま最適な条件下で合成されたものが機能を発現しているのが現状である。以上の理由からナノ粒子のサイズ選別・組成選別を行い蓄電性を発現する要因を明らかにすることが大切となってくる。これらの状況を踏まえ本研究では粒子を大きさごとに分別し細かく分析することが重要であると考え初年度では微分型微粒子分級装置（DMA）を開発しナノ粒子のサイズ選別を行い、基板上に堆積させる。本実験では堆積させる基板はプラズマ直下ではないため室温、またはペルチェにより冷却が可能で基板上でのマイグレーションを防ぐことができる。サイズ選別に関しては、10 －160 nmのナノ粒子を中心に分級できる装置の開発を目的として研究を進めた。装置の開発は完了しており計画通り進んでいる。しかし本研究で対象とする圧力が既往の研究で報告されている圧力に比べてかなり低いことから電圧の大きさと実際に分級される粒子の大きさの対応を取る必要がでてきた。
  • CNT直接合成による充填層有効熱伝導率向上技術の開発
    公益財団法人中国電力技術研究財団：試 験 研 究－(Ａ)
    研究期間 : 2011年 -2012年 
    代表者 : 井上修平
  • 文部科学省：科学研究費助成事業(若手研究(B))
    研究期間 : 2011年 -2012年 
    代表者 : 井上 修平
     
    充填層の有効熱伝導率の低さは熱工学上の大きな課題である。これまで数多くの手法が試されてきたがいずれも粒子と伝熱媒体との間の接触熱抵抗がボトルネックとなり大きな改善は得られなかった。本研究では充填層粒子に直接単層カーボンナノチューブを合成することでこの解決を試みた。結果的に空隙に対して7 %のナノチューブを合成するだけで有効熱伝導率が3倍になることが分かった。
  • 文部科学省：科学研究費助成事業(若手研究(B))
    研究期間 : 2005年 -2005年 
    代表者 : 井上 修平
  • CVD法によるカーボンナノチューブの局所・均質生成法の開発に関する研究
    マツダ財団：マツダ研究助成
    研究期間 : 2004年 -2005年 
    代表者 : 井上修平

委員歴

  • 2012年04月 - 現在   中四国熱科学・工学研究会   委員
  • 2012年04月 - 現在   日本伝熱学会中国四国支部   委員
  • 2020年04月 - 2022年03月   日本機械学会   熱工学部門運営委員
  • 2018年04月 - 2022年03月   日本機械学会   日本機械学会熱工学部門出版委員会 委員
  • 2020年04月 - 2021年03月   日本機械学会   熱工学部門学会賞委員会 幹事
  • 2014年04月 - 2016年03月   日本伝熱学会   特定推進研究課題 「ナノスケール伝熱の学理と技術および応用への展望」

社会貢献活動

  • 熱力学の第１法則および第２法則、熱移動の主な形態である熱伝導、対流（凝縮、沸騰を含む）および熱ふく射
    期間 : 2020年03月19日 - 2020年03月24日
    役割 : 講師
    種別 : 出前授業
    主催者・発行元 : 広島大学フェニックス協力会
    　online
  • 熱力学の第１法則および第２法則、熱移動の主な形態である熱伝導、対流（凝縮、沸騰を含む）および熱ふく射
    期間 : 2019年11月13日 - 2019年11月13日
    役割 : 講師
    種別 : 出前授業
    主催者・発行元 : 広島大学フェニックス協力会
    　広島大学東千田未来創生センター
  • 熱力学・伝熱工学 －熱力学の第１法則および第２法則 熱移動の主な形態である熱伝導、対流（凝縮、沸騰を含む）および熱ふく射－
    期間 : 2018年11月16日 - 2018年11月16日
    役割 : 講師
    種別 : 出前授業
    　広島大学千田キャンパス
  • 熱力学の第１法則および第２法則、熱移動の主な形態である熱伝導、対流（凝縮、沸騰を含む）および熱ふく射
    期間 : 2017年12月16日 - 2017年12月16日
    役割 : 講師
    種別 : 出前授業
    主催者・発行元 : 広島大学フェニックス協力会
    　広島大学東千田未来創生センター

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