Updated on 2024/02/27

写真a

 
FUWA, Akio
 
Affiliation
Faculty of Science and Engineering
Job title
Professor Emeritus
Degree
Ph.D. ( Stanford University )

Committee Memberships

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    資源素材学会  素材部門委員会 幹事

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    The Mining and Materials Processing Institute of Japan  Materials Processing Society, Committee member

Professional Memberships

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    TMS-AIME

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    金属学会

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    資源素材学会

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    The Metallurgical Society of AIME

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    Japan Institute of Metals

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    The Mining and Materials Processing Institute of Japan

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Research Interests

  • 素材プロセス工学

  • 機能素材工学

  • 非鉄金属製錬

  • etc

  • Process Engineering

  • Materials Processings

  • Non-Ferrous Metallurgy

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Research Projects

  • 量子化学による材料の速度論ならびに設計

    Project Year :

    1985
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  • 材料製造における移動速度論(CVD反応解析、YSZ製造、他)

    Project Year :

    1985
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  • 金属製錬の基礎研究(シリコン製錬、亜鉛製錬、銅製錬、チタン製錬、その他)

    Project Year :

    1985
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  • Quantum Chemical Analysis in Materials Processing

    Project Year :

    1985
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  • Transport Phenomena in Materials Processing

    Project Year :

    1985
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  • Non-Ferrous Matallurgy(Silicon, Zinc, Titan, Copper, etc), Materials Synthesis uing electrochemical technique,etc

    Project Year :

    1985
    -
     
     

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Misc

  • Effects of cluster size on calculation of activation energies of silicon surface reactions with H-2 and HCl

    Nilson Kunioshi, Keisuke Anzai, Harunobu Ushijima, Akio Fuwa

    JOURNAL OF CRYSTAL GROWTH   418   115 - 119  2015.05

     View Summary

    In order to determine the effect of cluster size on the calculation of activation energies of reactions at silicon surfaces, intradimer adsorption/desorption reactions of H-2 and HCl with silicon clusters of various sizes and shapes were analyzed under the B3LYP/6-31G(d,p) level. Activation energies of reactions of H-2 and HCl with clusters composed of different number and orientation of dimers on the surface were estimated. For clusters having dimers parallel to each other, the activation energies converged satisfactorily at three (timers, but for clusters having dimers aligned in a row, activation energies did not converge sufficiently even at four dimers. The activation energies for clusters having three dimers parallel to each other on the surface were seen to be in good agreement with values published in the literature, but considering potential application of the cluster to model intrarow and interrow reaction mechanisms, reactions of H-2 and HCl with a cluster having three dimers parallel to each other and three (timers aligned in a row on the surface were also investigated, and the resultant activation energies were in even better agreement with published values. (C) 2015 Elsevier B.V. All rights reserved.

    DOI

  • Effects of cluster size on calculation of activation energies of silicon surface reactions with H-2 and HCl

    Nilson Kunioshi, Keisuke Anzai, Harunobu Ushijima, Akio Fuwa

    JOURNAL OF CRYSTAL GROWTH   418   115 - 119  2015.05

     View Summary

    In order to determine the effect of cluster size on the calculation of activation energies of reactions at silicon surfaces, intradimer adsorption/desorption reactions of H-2 and HCl with silicon clusters of various sizes and shapes were analyzed under the B3LYP/6-31G(d,p) level. Activation energies of reactions of H-2 and HCl with clusters composed of different number and orientation of dimers on the surface were estimated. For clusters having dimers parallel to each other, the activation energies converged satisfactorily at three (timers, but for clusters having dimers aligned in a row, activation energies did not converge sufficiently even at four dimers. The activation energies for clusters having three dimers parallel to each other on the surface were seen to be in good agreement with values published in the literature, but considering potential application of the cluster to model intrarow and interrow reaction mechanisms, reactions of H-2 and HCl with a cluster having three dimers parallel to each other and three (timers aligned in a row on the surface were also investigated, and the resultant activation energies were in even better agreement with published values. (C) 2015 Elsevier B.V. All rights reserved.

    DOI

  • Mossbauer Spectroscopy of the Magnetic-Field-Induced Ferroelectric Phase of CuFeO2

    Shin Nakamura, Yasuhiro Kobayashi, Shinji Kitao, Makoto Seto, Akio Fuwa, Noriki Terada

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   84 ( 2 )  2015.02

     View Summary

    Fe-57 Mossbauer spectroscopy in an applied magnetic field has been conducted on single crystals of CuFeO2 and CuFe0.965Ga0.035O2 in order to investigate magnetic-field-induced ferroelectric states. The Mossbauer spectra observed under a magnetic field change significantly, corresponding to magnetic-field-induced phase transitions. In the ferroelectric incommensurate (FEIC) phase (7 < H-ex < 13 T), the spectrum can be explained by a model with spins distributed at approximately 20, 95, and 160 degrees from the c-axis in the (110) plane. This spin configuration resembles the "complex noncollinear spin configuration (CNC)" model proposed theoretically. In the FEIC phase, the isomer shift is larger, while the quadrupole splitting and average hyperfine field are smaller than those in the collinear four sublattice (4SL, 0 < H-ex < 7 T) and five sublattice (5SL, H-ex > 13 T) phases. In addition, a noticeable change in the hyperfine field is observed with varying magnetic field. We consider that these changes indicate the change in the electronic state of the Fe3+ ion, possibly modified by a spin-orbit interaction.

    DOI

  • Mossbauer Spectroscopy of the Magnetic-Field-Induced Ferroelectric Phase of CuFeO2

    Shin Nakamura, Yasuhiro Kobayashi, Shinji Kitao, Makoto Seto, Akio Fuwa, Noriki Terada

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   84 ( 2 )  2015.02

     View Summary

    Fe-57 Mossbauer spectroscopy in an applied magnetic field has been conducted on single crystals of CuFeO2 and CuFe0.965Ga0.035O2 in order to investigate magnetic-field-induced ferroelectric states. The Mossbauer spectra observed under a magnetic field change significantly, corresponding to magnetic-field-induced phase transitions. In the ferroelectric incommensurate (FEIC) phase (7 < H-ex < 13 T), the spectrum can be explained by a model with spins distributed at approximately 20, 95, and 160 degrees from the c-axis in the (110) plane. This spin configuration resembles the "complex noncollinear spin configuration (CNC)" model proposed theoretically. In the FEIC phase, the isomer shift is larger, while the quadrupole splitting and average hyperfine field are smaller than those in the collinear four sublattice (4SL, 0 < H-ex < 7 T) and five sublattice (5SL, H-ex > 13 T) phases. In addition, a noticeable change in the hyperfine field is observed with varying magnetic field. We consider that these changes indicate the change in the electronic state of the Fe3+ ion, possibly modified by a spin-orbit interaction.

    DOI

  • Valence instability of iron oxide ultrafine particles on ferroelectrics studied by Mossbauer spectroscopy

    Jun Kano, Takumi Okamoto, Shin Nakamura, Akio Fuwa, Takafumi Otoyama, Yoshiaki Nakazaki, Hideki Hashimoto, Jun Takada, Norihiro Oshime, Miho Ito, Naoshi Ikeda

    JAPANESE JOURNAL OF APPLIED PHYSICS   53 ( 5 ) 05FB24  2014.05

     View Summary

    Various types of iron oxides loaded on ferroelectric BaTiO3 and nonferroelectric ZrO2 supports have been studied by Fe-57 Mossbauer spectroscopy to investigate the valence instability of iron oxides affected by ferroelectric polarization fluctuation. Although the iron oxide loaded on ZrO2 shows a typical reduction process at high vacuum and high temperature, the iron oxide loaded on BaTiO3 shows an opposite process, i.e., iron oxide oxidization. We propose the dynamics of band structures of ferroelectrics in the paraelectric phase to understand this phenomenon. The oscillation of band bending causes electron transfer from an iron oxide to a ferroelectric support. This result suggests that the surface charges of ferroelectrics are useful in developing new functional materials with metal compounds. (C) 2014 The Japan Society of Applied Physics

    DOI

  • Valence instability of iron oxide ultrafine particles on ferroelectrics studied by Mossbauer spectroscopy

    Jun Kano, Takumi Okamoto, Shin Nakamura, Akio Fuwa, Takafumi Otoyama, Yoshiaki Nakazaki, Hideki Hashimoto, Jun Takada, Norihiro Oshime, Miho Ito, Naoshi Ikeda

    JAPANESE JOURNAL OF APPLIED PHYSICS   53 ( 5 ) 05FB24  2014.05

     View Summary

    Various types of iron oxides loaded on ferroelectric BaTiO3 and nonferroelectric ZrO2 supports have been studied by Fe-57 Mossbauer spectroscopy to investigate the valence instability of iron oxides affected by ferroelectric polarization fluctuation. Although the iron oxide loaded on ZrO2 shows a typical reduction process at high vacuum and high temperature, the iron oxide loaded on BaTiO3 shows an opposite process, i.e., iron oxide oxidization. We propose the dynamics of band structures of ferroelectrics in the paraelectric phase to understand this phenomenon. The oscillation of band bending causes electron transfer from an iron oxide to a ferroelectric support. This result suggests that the surface charges of ferroelectrics are useful in developing new functional materials with metal compounds. (C) 2014 The Japan Society of Applied Physics

    DOI

  • Local and dynamic Jahn-Teller distortion in ulvospinel Fe2TiO4

    Shin Nakamura, Akio Fuwa

    HYPERFINE INTERACTIONS   226 ( 1-3 ) 267 - 274  2014.04

     View Summary

    Fe-57 Mossbauer spectroscopic study on ulvospinel Fe2TiO4 has been conducted in a wide temperature range from 16 K to 500 K. The paramagnetic spectra are composed of several high spin Fe2 + doublets even at 500 K, which is rather strange because the point symmetry of the A-site is completely cubic (-aEuro parts per thousand 43m). We explain the electric field gradient (EFG) at A-site by the local arrangement of Fe2 + and Ti4 + on the B-site. The spectra were successfully analyzed by four-subspectra model, which is based on the B-site arrangement. The model also fits rather well to the magnetically ordered spectra. Thus the temperature variations of the hyperfine parameters were obtained. The N,el temperature (T (N)) is estimated to be about 125 K. The quadrupole coupling constants e (2) qQ/2 of A-site subspectra show little change around cubic-tetragonal transition temperature (T (t) = 163 K), but rapidly increase below T (N). From the temperature variation of line width, we found local and dynamic Jahn-Teller distortions around A-site Fe2 + ions in the cubic phase.

    DOI

  • Mossbauer Study of the Ferroelectric State in Ga-Substituted CuFeO2

    Shin Nakamura, Akio Fuwa, Noriki Terada

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   83 ( 4 ) 044701  2014.04

     View Summary

    Fe-57 Mossbauer spectroscopic measurements have been conducted on CuFe1-xGaxO2 single crystals, in order to investigate the magnetic structures and hyperfine parameters in ferroelectric CuFe0.965Ga0.035O2 and paraelectric CuFeO2. We confirmed that the Mossbauer spectrum at 4.2 K in CuFeO2 is explained by the collinear antiferromagnetic structure with spins along the hexagonal c-axis. In the ferroelectric phase in CuFe0.965Ga0.035O2, the spectrum consists of three magnetic components, where magnetic hyperfine fields distribute in three different directions within the (110) plane. This configuration is not completely consistent with a simple proper screw structure with a uniform spin distribution. The quadrupole coupling constants e(2)qQ/2 are unexpectedly large for both specimens. In the ferroelectric state in CuFe0.965Ga0.035O2, e(2)qQ/2 becomes noticeably smaller than that in the paraelectric phase in CuFeO2. We discuss the difference in quadrupole coupling constant between the ferroelectric and paraelectric states in CuFe1-xGaxO2.

    DOI

  • Mossbauer Study of the Ferroelectric State in Ga-Substituted CuFeO2

    Shin Nakamura, Akio Fuwa, Noriki Terada

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   83 ( 4 ) 044701  2014.04

     View Summary

    Fe-57 Mossbauer spectroscopic measurements have been conducted on CuFe1-xGaxO2 single crystals, in order to investigate the magnetic structures and hyperfine parameters in ferroelectric CuFe0.965Ga0.035O2 and paraelectric CuFeO2. We confirmed that the Mossbauer spectrum at 4.2 K in CuFeO2 is explained by the collinear antiferromagnetic structure with spins along the hexagonal c-axis. In the ferroelectric phase in CuFe0.965Ga0.035O2, the spectrum consists of three magnetic components, where magnetic hyperfine fields distribute in three different directions within the (110) plane. This configuration is not completely consistent with a simple proper screw structure with a uniform spin distribution. The quadrupole coupling constants e(2)qQ/2 are unexpectedly large for both specimens. In the ferroelectric state in CuFe0.965Ga0.035O2, e(2)qQ/2 becomes noticeably smaller than that in the paraelectric phase in CuFeO2. We discuss the difference in quadrupole coupling constant between the ferroelectric and paraelectric states in CuFe1-xGaxO2.

    DOI

  • 塩基性浴での電析によるBiSb-Te薄膜熱電素子の作製

    鈴木佑輝, 陳 子諒, 不破章雄

    日本金属学会誌   78巻・8号・   310 - 316  2014

    DOI

  • Local and dynamic Jahn-Teller distortion in ulvöspinel Fe2TiO4

    Shin Nakamura, Akio Fuwa

    Hyperfine Interactions   226 ( 1-3 ) 267 - 274  2014

     View Summary

    57Fe Mössbauer spectroscopic study on ulvöspinel Fe2TiO4 has been conducted in a wide temperature range from 16 K to 500 K. The paramagnetic spectra are composed of several high spin Fe2+ doublets even at 500 K, which is rather strange because the point symmetry of the A-site is completely cubic (- 43m). We explain the electric field gradient (EFG) at A-site by the local arrangement of Fe2+ and Ti4+ on the B-site. The spectra were successfully analyzed by four-subspectra model, which is based on the B-site arrangement. The model also fits rather well to the magnetically ordered spectra. Thus the temperature variations of the hyperfine parameters were obtained. The Néel temperature (TN) is estimated to be about 125 K. The quadrupole coupling constants e2 qQ/2 of A-site subspectra show little change around cubic-tetragonal transition temperature (Tt = 163 K), but rapidly increase below TN. From the temperature variation of line width, we found local and dynamic Jahn-Teller distortions around A-site Fe2+ ions in the cubic phase. © 2013 Springer Science+Business Media Dordrecht.

    DOI

  • Observation of the charge order in perovskite manganite Pr0.5Ca0.5MnO3 by Mossbauer quadrupole effect

    Shin Nakamura, Akio Fuwa, Yorihiko Tsunoda

    HYPERFINE INTERACTIONS   208 ( 1-3 ) 29 - 32  2012.03

     View Summary

    The charge order in a perovskite manganite Pr0.5Ca0.5MnO3 was investigated by Mossbauer spectroscopy. The quadrupole splitting and the absorption line width jump to an increase when lowering the temperature below 230 K (T-co), which is indicative of a phase transition to a monoclinic structure due to the charge ordering, or due to a local Jahn-Teller effect due to the presence of Mn3+ ions. The intensity ratio of the doublet lines also changes at T-co. Local and dynamical Jahn-Teller effect (polarons) with a relaxation time of 10(-8) s is present even in the metallic state.

    DOI

  • Mossbauer study on Y-type hexaferrite Ba2Mg2Fe12O22

    Shin Nakamura, Yorihiko Tsunoda, Akio Fuwa

    HYPERFINE INTERACTIONS   208 ( 1-3 ) 49 - 52  2012.03

     View Summary

    Mossbauer study on a Y-type hexaferrite Ba2Mg2Fe12O22 has been conducted by using a single crystal specimen. The spins are in the c-plane down to 60 K. For 18h(VI) site Fe, the quadrupole shifts and the outermost line width change around 195 K, where the transition from ferrimagnetic to proper screw spin structure takes place. Below 50 K, the spin reorientation transition to a longitudinal conical structure was also recognized. At 16 K, the spins incline about 15 degrees from the c-plane.

    DOI

  • Observation of the charge order in perovskite manganite Pr0.5Ca0.5MnO3 by Mossbauer quadrupole effect

    Shin Nakamura, Akio Fuwa, Yorihiko Tsunoda

    HYPERFINE INTERACTIONS   208 ( 1-3 ) 29 - 32  2012.03

     View Summary

    The charge order in a perovskite manganite Pr0.5Ca0.5MnO3 was investigated by Mossbauer spectroscopy. The quadrupole splitting and the absorption line width jump to an increase when lowering the temperature below 230 K (T-co), which is indicative of a phase transition to a monoclinic structure due to the charge ordering, or due to a local Jahn-Teller effect due to the presence of Mn3+ ions. The intensity ratio of the doublet lines also changes at T-co. Local and dynamical Jahn-Teller effect (polarons) with a relaxation time of 10(-8) s is present even in the metallic state.

    DOI

  • Mossbauer study on Y-type hexaferrite Ba2Mg2Fe12O22

    Shin Nakamura, Yorihiko Tsunoda, Akio Fuwa

    HYPERFINE INTERACTIONS   208 ( 1-3 ) 49 - 52  2012.03

     View Summary

    Mossbauer study on a Y-type hexaferrite Ba2Mg2Fe12O22 has been conducted by using a single crystal specimen. The spins are in the c-plane down to 60 K. For 18h(VI) site Fe, the quadrupole shifts and the outermost line width change around 195 K, where the transition from ferrimagnetic to proper screw spin structure takes place. Below 50 K, the spin reorientation transition to a longitudinal conical structure was also recognized. At 16 K, the spins incline about 15 degrees from the c-plane.

    DOI

  • A study on the recycling of valuable metals (Mo, V, Ni) from desulphurization catalysts

    NAGANE Shogo, KUKUTSU Takahiko, FUWA Akio

    Shigen-to-Sozai   128 ( 8 ) 526 - 530  2012

     View Summary

    In order to recover and recycle the valuable metals, such as Mo, Ni and V on γ-Al2O3 supported catalyst, which has been used for desulfurization in petroleum refining process, three step process, i.e. air-oxidation roasting step at temperatures from 400 to 900°C, alkaline leaching step using sodium hydroxide and carbonate solution and hydrogen reduction-hydrochloric acid leaching step, has been experimentally conducted for its process feasibility. It has been known that NiAl2O4 spinel compound formation in the roasting step hinders the leaching of Ni, which leads us to the reducing-acid leaching step of the alkaline leach residue. It has been shown that (1) in the roasting step, better elimination of hydrocarbon and sulfur constituents is attained at temperature at temperatures, 700 to 900°C, with resultant formation of Mo and V oxides and Ni spinel compound, (2) better leaching rate of Mo and V, 97% and 89% respectively, and the least leaching rate of Al (around, 0.6%) using sodium carbonate solution and (3) high Ni leaching rate of 80% has been attained in the final step. Thus, using this three step process, reasonable rate recovery of Mo, V and Ni has been shown feasible and this process scheme could be applicable for recovery Mo, Co and V in desulfurization catalysis.

    DOI CiNii

  • Reaction Analysis of Carbon Deposition in Carbon Dioxide Reforming by ab Initio Molecular Orbital Study

    TAKEUCHI Takumi, MOROTOME Kensaku, FUWA Akio

    JEC   18 ( 1 ) 1 - 8  2008

     View Summary

    In the CO2 reforming reaction using CH4, carbon precipitation on metal catalysis takes place making the catalysis inactive and useless. In this study, we have suggested two reaction pathways of carbon deposition process on Pd8 (111) cluster in CO2-CH4 reforming reaction, which are i.e. Path 1 and Path 2, shown below;<BR>Path 1<BR>       CO+* → CO-*<BR>       CO-*+CO → C-*+CO2<BR>Path 2<BR>       CO+*+* →  C-*+O-*<BR>       O-*+CO → CO2+*<BR>   where * is a adsorption site on a catalysis.<BR>The results obtained in the analysis of these two reaction pathways using ab initio molecular orbital method are as follows: (1) energy profile diagrams of those reaction pathways to elucidate the preferred pathway of carbon deposition and (2) electron transfer and population analysis from and to the Pd cluster. Through this analysis, Path 2 appears the preferred reaction path in the present carbon precipitation reaction scheme.

    DOI CiNii

  • 塩基性アンモニア浴からのBi2Te3薄膜の電析と熱電特性

    平本貴則, 杉山真悟, 石森康浩, 不破章雄

    日本金属学会誌   72 ( 9 ) 745 - 750  2008

    DOI CiNii

  • Zinc Vaporization Kinetics from Zinc Smelting Slag

    Yasuhiro Hayashi, Akio Fuwa

    Zinc and Lead Metallurgy2008, Met-Soc, CIM     77 - 88  2008

  • Zinc Vaporization Kinetics from Zinc Smelting Slag

    Yasuhiro Hayashi, Akio Fuwa

    Zinc and Lead Metallurgy2008, Met-Soc, CIM     77 - 88  2008

  • Catalytic Roles of V_2O_5 on Benzene Ring Decomposition using Ab Initio Molecular Orbital Method

    AOYAGI Yuichi, KUWANO Yoshihiro, FUWA Akio

    JEC   17 ( 1 ) 37 - 45  2007

     View Summary

    In this study, in order to elucidate benzene decomposition reaction path on V2O5 catalysis, ab initio molecular orbital calculation has been conducted for 5 elemental reaction steps involved in the reaction between benzene and V2O9H8 cluster, proposed by Jaine, et al., i.e. benzene adsorption, hydrogen atom surface transfer, hydrogen gas de-sorption, oxygen gas adsorption and benzene ring decomposition. Molecular structures in stable state, transition state and intermediate molecular structures have been revealed in this proposed reaction steps. The reaction scheme can be described as follows; (1) electron in benzene transfer themselves to the catalysis cluster, whereby hydrogen atom transfer on the catalysis surface proceeds for the subsequent hydrogen molecular gas de-sorption, and (2) benzene ring decomposition takes place via the unique Mars-van Krevelen mechanism on V2O5 catalysis.

    DOI CiNii

  • Chloride Capacity in FeO-Fe2O3-SiO2 molten salt at 1523K

    Y. Yamashita, A. Fuwa, F. Tanaka

    Sohn International Symposium: Advanced Processing of Metals and Materials:TMS-AIME     503 - 513  2006

  • Titanium Metal Via Magnesium Reduction of Titanium Subchloride Species

    A. Fuwa, M. Tsumura, M. Watanabe, M. Yoshino

    The 16 th IKETAMI Conference on Electrochemistry and Thermodynamics on Materials Processing for Sustainable Production     695 - 714  2006

  • Fabrication of a Cu nanodot array based on electroless plating employing a diblock copolymer nanotemplate

    S Asakura, A Hozumi, A Fuwa

    JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A   23 ( 4 ) 1137 - 1140  2005.07

     View Summary

    An array of copper (Cu) nanodots was fabricated onto a Si substrate covered with native oxide (SiO2/Si) using a diblock copolymer as a resist film. First, polystyrene/polymethylmethacrylate (PS/PMMA) diblock copolymer was spin-coated on a SiO2/Si substrate and then annealed for 24 h in a vacuum oven maintained at 170 degrees C to achieve good phase separation. To prepare a nanotemplate, this phase-separated diblock copolymer film was photodecomposed selectively using 172 nm vacuum ultraviolet (VUV) light. Due to the difference in photoetching rate between PS and PMMA domains, the latter regions were preferentially decomposed. By controlling the VUV irradiation conditions, that is, exposure time and atmospheric pressure, we were able to prepare a diblock copolymer template comprised of a nanoporous PS matrix on the SiO2/Si surface. Next, the nanopore regions were site-selectively modified through a vapor phase chemisorption of an amino-terminated organosilane. Palladium (Pd[II]) particles were then immobilized onto the amino-terminated nanopore regions through donor and accepter reactions and, subsequently, Cu was selectively electroless-plated onto these Pd-activated regions. As evidenced by atomic force microscopy, due to the elimination of the residual PS nanotemplate by VUV irradiation, we fabricated an array of Cu nanodots 3.0 to similar to 4.3 nm in height and 10 to similar to 25 nm in diameter on the entire 10 x 10 mm(2) area of the SiO2/Si substrate. (c) 2005 American Vacuum Society.

    DOI

  • クエン酸浴から電析されたZnTe薄膜のホール効果測定による電気的特性の評価

    大友健志, 石崎貴裕, 萩原大輔, 川原田洋, 不破章雄

    日本金属学会誌   69 ( 3 ) 298 - 302  2005

    DOI CiNii

  • 銅微細パターン作製のための172nm真空紫外光を用いた液晶ポリマーフィルムの表面改質

    福谷修平, 浅倉秀一, 不破章雄

    エレクトロニクス実装学会誌   8 ( 4 ) 325 - 329  2005

    DOI CiNii

  • Evaluation of Changes in Chemical Structures of Poly (methyl-methacrylate) using 172nm Vacuum Ultraviolet light

    YAMAGUCHI Takahiko, ASAKURA Shuichi, FUWA Akio

    Materials life   17 ( 4 ) 140 - 145  2005

     View Summary

    We evaluated structural changes of poly (methyl-methacrylate) (PMMA) surfaces after and before vacuum ultraviolet (VUV)-irradiation using X-ray photoelectron spectroscopy (XPS) and Fourier trans form infrared spectroscope reflection absorption Spectroscopy (FTIR-RAS). When the PMMA films were irradiated with VUV light under reduced pressure of 100Pa, XPS measurements showed that the O/C value decreased from 0.40 before VUV irradiation to 0.10 after irradiation at 100Pa for 10 min. FT-IR spectral results indicated that C=O and ester peaks, which are parts of PMMA structures, were reduced by the VUV-irradiation. These results showed that oxygen-groups existed on the PMMA surface were decom posed by VUV-irradiation at 100 Pa. However, these structural changes weren't observed when the PMMA was irradiated at 103 Pa. Furthermore, we confirmed that C=O and ester peaks were reduced by VUV-irradiation at N2 atmosphere. This result was the same as the case of VUV-irradiation at 100 Pa. Although unirradiated PMMA was removed by toluene rinsing, the cured PMMA by VUV-irradiation at 100 Pa could not dissolve. Utilizing these properties, we could prepare negative and positive-tone PMMA micropattems by VUV-light lithography through a photomask.

    DOI CiNii

  • Fabrication of high-density copper microstructures using vacuum ultraviolet light lithography and hydrofluoric acid etching treatment

    S Asakura, A Hozumi, T Yamaguchi, A Fuwa

    THIN SOLID FILMS   467 ( 1-2 ) 127 - 132  2004.11

     View Summary

    This paper describes a method to fabricate high-density copper microstructures on an indium tin oxide (ITO) surface. Lithography using 172-nm vacuum ultraviolet (VUV) light was found to not decompose the siloxane network at the bottom of a methyl-terminated organosilane self-assembled monolayer (SAM) deposited on an ITO substrate. When copper was electrodeposited onto this ITO surface covered a SAM/siloxane network pattern, it deposited selectively onto the siloxane regions. However, the density of the electrodeposited copper was low. By applying a wet hydrofluoric (HF) acid treatment for an appropriate time after the lithography, we could effectively remove the siloxane network without damaging the organosilane SAM. In this manner, we were able to successfully fabricate high-density copper microstructures with 35 x 35 mum patterns. (C) 2004 Elsevier B.V. All rights reserved.

    DOI

  • Fabrication of built-in copper microstructures on epoxy resin

    S Asakura, S Fukutani, A Fuwa

    MICROELECTRONIC ENGINEERING   75 ( 4 ) 375 - 382  2004.11

     View Summary

    This paper describes a simple and effective method to fabricate built-in copper microstructures on a polymer substrate. Our method uses a micropatterned amino (NH2)-terminated self-assembled monolayer (SAM) as a template to fabricate patterned copper (Cu) film for transfer to an epoxy resin. Cu microstructures were first formed on a photolithographically micropatterned NH2-SAM-covered SiO2/Si substrate through conventional electroless plating, in which Cu deposition proceeded selectively on the NH2-terminated areas while the photo-irradiated areas remained free of copper deposits. Next, epoxy glue (resin) was poured into a Teflon(R) O-ring placed so as to surround the Cu-micro-patterned substrate. Finally, after the resin completely hardened, it was removed from the substrate. Due to the weak adhesion between the Cu film and the NH2-terminated surface, the area-selectively deposited Cu film could be readily peeled off and removed from the SiO2/Si substrate and thus transferred to the resin surface. Through this technique, high-resolution 10-mum-wide Cu microstructures were successfully fabricated on the epoxy resin surface. These embedded Cu microstructures were tightly adhered to the resin. No peeling of the copper structures was observed in a Scotch(R) tape peeling test. (C) 2004 Elsevier B.V. All rights reserved.

    DOI

  • Photoinduced decomposition of alkyl monolayers using 172 nm vacuum ultraviolet light

    N Shirahata, K Oda, S Asakura, A Fuwa, Y Yokogawa, T Kameyama, A Hozumi

    JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A   22 ( 4 ) 1615 - 1619  2004.07

     View Summary

    The photoinduced stability of two alkyl monolayers on Si has been investigated using a Xe-2 excimer lamp radiating 172 nm vacuum ultraviolet (VUV) light. The photoinduced stability of I-octadecene monolayer (ODM) was compared with that of alkylsilane monolayer. I-octadecene was employed as a starting precursor of alkyl monolayer on Si. The alkylsilane monolayer was formed from otadecyltrimethoxysilane monoalyer (OTSM) onto the SiO2/Si substrate. The decomposition of ODM was investigated under VUV irradiation conducted at 10 and 10(5) Pa. The VUV light decomposed ODM at both 10 and 105 Pa. The photodecomposition rate at 105 Pa was smaller than that at 10 Pa. The decomposed methyl and ethyl groups from the alkyl chain formed carboxyl groups. The carboxyl coverage on the surface of Si increased with increasing VUV irradiation time ranging from 0 to 60 s at 10 Pa, and decreased after 60 s. In contrast, the Si-O component in x-ray photoelectron Si 2p spectrum drastically increased after the VUV irradiation time of 60 s. The Si-O component indicated complete covering of Si surface. Similar decomposition rates between ODM and OTSM were observed for the VUV irradiation time ranging from 0 to 45 s conducted at 10 Pa. After 45 s, the photodecomposition rate of ODM was smaller than that of OTSM. The effectiveness of VUV light for the micropatterning of ODM was also investigated. (C) 2004 American Vacuum Society.

    DOI

  • Wettability control of a polymer surface through 126 nm vacuum ultraviolet light irradiation

    A Hozumi, N Shirahata, Y Nakanishi, S Asakura, A Fuwa

    JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A   22 ( 4 ) 1309 - 1314  2004.07

     View Summary

    The control of the surface wettability of poly (methyl methacrylate) (PMMA) substrates has been successfully demonstrated using an Ar-2* excimer lamp radiating 126 nm vacuum ultraviolet (VUV) light. Each of the samples was exposed to 126 nm VUV light in air over the pressure range of 2 x 10(-4)-10(5) Pa. Although at the process pressures of 10, 10(3), and 10(5) Pa, the PMMA surfaces became relatively hydrophilic, the degree of hydrophilicity depended markedly on the pressure. The minimum water contact angles of the samples treated at 10, 10(3), and 10(5) Pa were about 50degrees, 33degrees, and 64degrees, respectively. These values were larger than those of PMMA substrates hydrophilized through 172 nm VUV irradiation conducted under the same conditions. On the other hand, after 126 nm VUV irradiation conducted under the high vacuum condition of 2 x 10(-4) Pa, the PMMA substrate surface became carbon-rich, probably due to preferential cross-linking reactions, as evidenced by x-ray photoelectron spectroscopy. This surface was hydrophobic, showing a water contact angle of about 101degrees. Although the 126 nm VUV-irradiated surfaces appeared relatively smooth when observed by atomic force microscope, very small particles with diameters of 30-60 nm, which probably originated from the readhesion of photodecomposed products, existed on all of the sample surfaces. (C) 2004 American Vacuum Society.

    DOI

  • Ge-Sb-Te系による新規組成の薄膜作製および評価

    鈴木友宏, 石崎貴裕, 森暁, 不破章雄

    日本金属学会誌   68 ( 2 ) 90 - 93  2004

    DOI CiNii

  • ニトリロ三酢酸を添加した塩基性アンモニア浴からのBi2Te3電析

    石森康浩, 石崎貴裕, 大友健志, 不破章雄

    日本金属学会誌   68 ( 6 ) 406 - 411  2004

    DOI CiNii

  • Effect of pH on the electrodeposition of ZnTe film from a citric acid solution

    T. Ishizaki, T. Ohtomo, Y. Sakamoto, A. Fuwa

    Mater. Trans   45 ( 2 ) 277 - 280  2004

    DOI CiNii

  • Structural, optical and electrical properties of ZnTe thin films electrochemically deposited from a citric acid aqueous solution

    T Ishizaki, T Ohtomo, A Fuwa

    JOURNAL OF PHYSICS D-APPLIED PHYSICS   37 ( 2 ) 255 - 260  2004.01

     View Summary

    ZnTe thin films were electrodeposited onto Au-coated Cu substrates from an electrolytic solution containing ZnSO4, TeO2, citric acid and sodium citrate, and the dependence of structure, composition and surface morphology on the solution's Zn concentration were investigated. Results of examinations for resistivity and optical absorption demonstrated, respectively, that as the Zn concentration in the electrolyte was reduced over the range of 5-50 mmol dm(-3), the resistivity of the films obtained continuously decreased and their band gap increased. Quantative analysis of energy dispersive x-ray analysis and inductively coupled plasma results indicated that the composition ratio (Zn: Te) was approximately stoichiometric under all conditions in this study. X-ray diffraction results revealed that all the ZnTe thin films obtained showed a preferred (111) orientation with cubic structure. ZnTe thin films we transferred onto nonconductive epoxy resin also showed the same structure.

    DOI CiNii

  • Electrodeposition of ZnTe films with high current efficiency from citric acid aqueous solutions at low overpotential

    T. Ishizaki, T. Ohtomo, A. Fuwa

    J. Electrochem. Soc   151 ( 3 ) C161 - C167  2004

    DOI CiNii

  • Electrodeposition of Copper-indium-telluride films from hydrochloric acid solution

    T. Ishizaki, N. Saito, A. Fuwa

    Surf. Coat   182   159 - 160  2004

  • Electrodeposition of a copper-tellurium compound under diffusion-limiting control

    T Ishizaki, D Yata, A Fuwa

    MATERIALS TRANSACTIONS   44 ( 8 ) 1583 - 1587  2003.08

     View Summary

    Copper-tellurium films were electrochemically deposited from a Solution containing CuCl2, TeO2 and HCl This study revealed the relationship between the copper/tellurium ratio in the Solution and the metal ratio in the deposited film. The Cu/Te ratio of the deposited film was successfully controlled by conducting electrodeposition under diffusion-limited conditions. The [Cu]/[Te] ratio in the solution was linearly related to that of Cu/Te in the deposited film, since the partial current density originating from the copper and tellurium ions was directly proportional to the concentration of each. The deposited films crystallized to Cu,Te at the Cu/Te ratio of 2.5. The films were deposited at -0.4 V vs. Ag/AgCl from a solution in which [Cu]/[Te] = 2.5, [CuCl2] = 1.0 x 10(-3) M ( kmol m(-3)), [TeO2] = 4.0 x 10(-4) M. and pH = 1.

    DOI CiNii

  • Fabrication of microstructured copper on an indium-tin-oxide surface using a micropatterned self-assembled monolayer as a template

    S Asakura, M Hirota, A Fuwa

    JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A   21 ( 4 ) 1152 - 1156  2003.07

     View Summary

    The difference in chemical reactivity between indium-tin-oxide (ITO) and self-assembled monolayer (SAM) surfaces was used to fabricate copper (Cu) microstructures. ITO substrates coated with octadecyltrimethoxysilane (ODS)-SAM were photolithographically micropatterned using vacuum ultraviolet (VUV) light Each of the micropatterned samples was subsequently immersed in an electrodeposition bath in order to deposit Cu on its surface. As confirmed by atomic force microscopy, Cu electrodeposition proceeded selectively on the VUV-irradiated areas of the ITO surface while the ODS-SAM surface served effectively as a mask to block Cu deposition. Cu microstructures with 7.5 X 7.5 mum(2) features were successfully fabricated on the ITO surface. (C) 2003 American Vacuum Society.

    DOI

  • Elementary reaction path on polychlorinated biphenyls formation from polychlorinated benzenes in heterogeneous phase using ab initio molecular orbital calculation

    Mitsuhito Hirota, Hiromitsu Takashita, Junichi Kato, Akio Fuwa

    Chemosphere   50 ( 4 ) 457 - 467  2003.01

     View Summary

    We have investigated the elementary reaction path on the 3,3′,4,4′,5,5′-hexachlorinated biphenyl (HxCB) formation from two 1,2,3,5-tetrachlorobenzenes (TCBz) and the catalytic role of copper on this formation using ab initio molecular orbital calculation. The elementary reaction path on the 3,3′,4,4′,5,5′-HxCB formation from two 1,2,3,5-TCBzs has been shown to occur as follows: Step 1 - the dissociation of Cl atom substituted at 5-position in 1,2,3,5-TCBz, Step 2 - the association between Cl atom substituted at 5-position in another 1,2,3,5-TCBz and the Cl radical formed in Step 1, Step 3 - the elimination of Cl2 molecule from the intermediate species formed in Step 2, and Step 4 - the 3,3′,4,4′,5,5′-HxCB formation from the direct condensation of two 1,2,3-trichlorophenyl radicals formed in Step 1 and Step 3. The geometric factor, which decides the reactivity of this formation, is the C-Cl bond strength of 1,2,3,5-TCBz. The catalytic roles of copper are to stabilize the total energy in the adsorption of 1,2,3,5-TCBz onto the copper surface and to weaken the C-Cl bond strength due to the charge transfer from the 1,2,3,5-TCBz to the copper surface. Moreover, we have achieved the prediction of the minimum energy path on the formation of non- and mono-ortho polychlorinated biphenyls congeners for which TEFs have been determined. © 2002 Elsevier Science Ltd. All rights reserved.

    DOI PubMed

  • Development of the ISF Simulation Model and its Application to Practical Operation

    TANNO Fumio, MATSUZAKI Kenji, FUWA Akio

    Journal of MMIJ   119 ( 1 ) 17 - 22  2003

     View Summary

    A simulation model of the Imperial Smelting Furnace has been developed to improve the furnace operation. The model consists of top, shaft and bottom regions. Analysis in the shaft region is based on differential heat and materials balances taking account of reaction kinetics and heat transfer rate, and those in the top and the bottom regions are based on heat and materials balances under steady-state condition. Overall heat and materials balances, and longitudinal distributions of process variables such as temperatures of gas, sinter and coke, volume-flow rate of gas, mass-flow rates of sinter, coke and molten lead, gas composition and fractional conversion in the shaft region under a practical operating condition were calculated. The heat loss through the furnace wall and the temperature distribution calculated using the model are in good agreement with those observed. The model is capable of predicting any change in the furnace situation when the operating condition is altered.

    DOI CiNii

  • Analysis of ISF Performance using the ISF Simulation Model

    TANNO Fumio, MATSUZAKI Kenji, FUWA Akio

    Journal of MMIJ   119 ( 1 ) 23 - 25  2003

     View Summary

    Using the simulation model of the Imperial Smelting Furnace based on differential heat and materials balances developed by the authors, the behavior of ISF under various operating conditions was predicted, where the influence of change in an operating condition on furnace performance was estimated. The main findings are as follows:<BR>(1) With decreasing coke reactivity, zinc productivity increases and coke ratio decreases.<BR>(2) There are an optimum size of particle and an optimum height of charge for the furnace performance.<BR>(3) Pulverized coke injection improves the furnace performance.<BR>Analysis of furnace performance using the model is useful for further improvement of the furnace operation.

    DOI CiNii

  • Fabrication of Chemically Modified Micro-Well Arrays on a Polymer Substrate

    ASAKURA Shuuichi, HOZUMI Atsushi, FUWA Akio

    Jitsumu Hyomen Gijutsu   54 ( 9 ) 622 - 623  2003

    DOI CiNii

  • The decomposition mechanism of precursor 2,4,5-trichlorophenol for

    T. Araki, M. Hirota, A. Fuwa

    Yazawa International Symposium: Metallurgical and Materials Processing: Principles and Technologies; High-Temperature Metal Production   1   1069 - 1077  2003

  • Simulation of imperial smelting furnace operation using a mathematical model

    K Matsuzaki, F Tanno, A Fuwa

    METALLURGICAL AND MATERIALS PROCESSING: PRINCIPLES AND TECHNOLOGIES, VOL 2   2   63 - 77  2003

     View Summary

    A mathematical simulation model of the imperial Smelting Furnace operation has been developed for purpose of improving the furnace operation. The model consists of top, shaft and bottom regions. Analysis in the shaft region is based on differential heat and materials balances taking account of reaction kinetics and heat transfer rates, and those in the top and the bottom regions are based on heat and materials balances under a steady-state condition. Longitudinal distributions of process variables such as temperatures of gas, sinter and coke, gas composition and fractional conversion under a practical operating condition were calculated. With this model, the furnace performance under various operating conditions also can be shown reasonably predicted.

  • The catalytic roles of copper and iron chloride on polychlorinated

    M. Hirota, T. Araki, M. Michihashi, A. Fuwa

    Recycling and Waste Treatment in Mineral and Metal Processing: Technical and Economic Aspects, Lulea, Sweden, 16th-20th June     735 - 741  2002

  • The effect of sulfur dioxide addition on dioxins generation and decomposition behaviors by thermodynamic equilibrium calculation

    M. Hirota, S. Asakura, W. Takahama, A. Fuwa

    Recycling and Waste Treatment in Mineral and Metal Processing: Technical and Economic Aspects, Lulea, Sweden, 16th-20th June     693 - 701  2002

  • Theoretical study of dioxins formation considering copper catalytic effects using quantum chemistry calculation

    M. Hirota, A. Fuwa

    Annual Reports of Casio Science Promotion Foundation     68 - 69  2002

  • The Effect of Sulfur Dioxide Addition on Dioxins Generation and Decomposition Behaviors from Thermodynamics View.

    HIROTA Mitsuhito, FUWA Akio

    Resources Processing   49 ( 1 ) 16 - 22  2002

     View Summary

    The influence of sulfur dioxide addition on dioxins generation and decomposition behaviors has been evaluated by thermodynamic equilibrium calculations. The calculation conditions in this work were as follows: (1) the C-H-O-Cl quaternary system has the ratio of [C : H : O : Cl]=9 : 6 : 4 : 1, i.e. this system corresponds to the most typical generation region of dioxins, (2) total amount of respective elements (NC+NH+NO+NCl) is 1 mol, (3) sulfur dioxide is then added to this C-H-O-Cl quaternary system and (4) total pressure and temperature range were 1 atm and from 773 to 1773 K. The influence of sulfur dioxide addition is shown to change the oxygen potential, on which the dioxins generation and decomposition is independent, i.e. higher temperature and higher oxygen potential lead to dioxins decomposition. The essential effect of sulfur element is shown to reduce hydrogen chloride potential, leading less dioxins chlorination reaction.

    DOI CiNii

  • Reaction analysis on carbon dioxide reforming over nickel catalyst by quantum chemistry

    W. Takahama, M. Hirota, A. Fuwa

    Proc. Fourth Pacific Rim Int. Conf. on Advanced Materials and Processing (PRICM4), (The Japan Institute of Metals, 2001)     2217 - 2220  2001

  • Catalytic roles of copper on chlorination of precursor phenol for dioxins using ab initio molecular orbital calculation

    M. Hirota, T. Araki, A. Fuwa

    Mater. Trans., JIM   42 ( 12 ) 2537 - 2542  2001

    DOI

  • Quantum chemistry analysis on dioxins generation reactions via chlorination of precursor substances

    M. Hirota, S. Asakura, A. Fuwa

    Proc. Fourth Pacific Rim Int. Conf. on Advanced Materials and Processing (PRICM4), (The Japan Institute of Metals, 2001)     2213 - 2216  2001

  • Catalytic effect of copper on dibenzo-p-dioxin and polychlorinated

    M. Hirota, J. Kato, N. Saito, A. Fuwa

    Toxic. Environ. Chemosphere   81 ( 3 ) 133 - 147  2001

  • Preparation of YSZ thin films by RF plasma-enhanced metal organic chemical vapor depodition

    T Nishimura, T Ichikawa, N Saito, A Fuwa

    SECOND INTERNATIONAL CONFERENCE ON PROCESSING MATERIALS FOR PROPERTIES     267 - 270  2000

     View Summary

    Yttria-stabilized zirconia (YSZ) has high potential to be used as solid-oxide-fuel cell (SOFC) electrolyte. However, the high efficiency of SOFC has nut been yet achieved due to the high internal resistance of bulk electrolyte The resistance becomes lower with the decrease in the electrolyte thickness. Thus, the decrease in electrolyte thickness leads to lower internal resistance. The aim of this study is as follows: (a) to prepare the thin films of YSZ by inductively-coupled RF plasma-enhanced metal organic chemical vapor deposition (PEMOCVD) process using Zr(t-OC4H9)(4),Y(DPM)(3) and oxygen, and (b) to reveal the relationship between the structural characterizations and the process parameters.

  • Behavior of Cu-In-Te electrodeposition from acid solution

    T Ishizaki, N Saito, D Yata, A Fuwa

    SECOND INTERNATIONAL CONFERENCE ON PROCESSING MATERIALS FOR PROPERTIES     281 - 284  2000

     View Summary

    Ternary compound-semiconductor, CuInTe2, film was deposited cathodically under potentiostatic conditions on titanium substrate From aqueous solution containing CuCl2, InCl3, TeO2 and HCl in this study. Tnt deposition parameters such as electrolytic solution composition, potential and temperature were optimized for electrodeposition of CulnTe(2). Structural characterization of the deposited film was also carried out using XRD and SEM. Electrodeposited films were prepared and analyzed for their chemical composition using ICP. The ICP analyses showed that the stoichiometry of the films could be controlled by (1) the deposition potential and/or by (2) the electrolytic bath composition.

  • Electrodeposition of Cu-In alloy from the solution containing critic acid

    T. Ishizaki, N. Saito, A. Fuwa

    MMIJ, (2000) accepted.   116 ( 3 ) 217 - 221  2000

    DOI

  • Gas phase equilibria for dibenzo-p-dioxin, dibenzo-p-furane and biphenyl in the C-H-O system

    N.Saito, T. Ishizaki, A. Fuwa

    Toxicological and Environmental Chemosphere, (1999) accepted   75   165 - 177  2000

  • Thermodynamic investigation of the effect of oxygen and hydrogen

    N. Saito, T. Ishizaki, A. Fuwa

    Toxicological and Environmental Chemosphere, (1999) accepted.   74   161 - 179  2000

  • Kinetics of SiHCl3 and SiCl4 evolution in Si(s)-HCl(g) System by Ab-initio MO

    N. Saito, T. Ishizaki, A. Fuwa

    Mater. Trans., JIM. , (1999), accepted.   41 ( 3 ) 383 - 392  2000

    DOI

  • The roles of metallic compounds on dioxins generation-decomposition behavior from thermodynamics and quantum chemistry

    N Saito, M Hirota, T Ishizaki, A Fuwa

    SECOND INTERNATIONAL CONFERENCE ON PROCESSING MATERIALS FOR PROPERTIES     727 - 732  2000

     View Summary

    Owing to their extremely high toxicity in the environment, the dioxins have been attracting social, technical and scientific attention in recent years. The authors theoretically had predicted the thermodynamic properties of all the dioxins via quantum chemistry and statistical thermodynamics and elucidated the generation-decomposition behavior of dioxins in the equilibrium calculation of C-H-O-Cl system. In actual combustion processes, it is said that metallic compounds have much influences on the dioxins behavior. The aim of this study is to reveal the roles of metallic compounds the generation-decomposition behavior of dioxins is revealed from the viewpoints of quantum chemistry. Especially, the catalytic effect of copper has been investigated for the reaction, 2HCl(g)--&gt;H-2(g)+Cl-2(g) and for the etherification reaction from precursors, which is Phenol(g) here, to dioxins. The catalytic role of Cu is shown to have much influence on the generation -decomposition of dioxins.

  • Prediction for thermodynamic function of dioxins for gas phase using

    N. Saito, A. Fuwa

    CHEMOSPHERE   40 ( 2 ) 131 - 145  2000

    DOI

  • The effect of citric acid and EDTA addition on Cu-In alloy electrochemical deposition

    T Ishizaki, N Saito, A Fuwa

    MATERIALS TRANSACTIONS JIM   40 ( 9 ) 867 - 870  1999.09

     View Summary

    The standard electrode potential for Cu is 0.34V and that of In is -0.34 V, which means that their deposition potentials are far apart, making the co-deposition difficult from a simple solution containing Cu and In ions. In order to bring these deposition potntials closer, a complex forming reagent of citric or EDTA is added to the CuSO4-In-2(SO4)(3) solution. The effect of these reagents was examined by linear sweep veltammetric measurement. An electrochemical deposition experiment of Cu-In alloy was conducted where effect citric acid or EDTA addition, current density and Cu concentration were examined.

    DOI

  • Theoretical analysis for thermal chemical vapor deposition from tetraethoxysilane using a semi-empirical molecular orbital method

    M Hirota, N Saito, T Ishizaki, A Fuwa

    JOURNAL OF THE JAPAN INSTITUTE OF METALS   63 ( 7 ) 931 - 937  1999.07

     View Summary

    In order to elucidate the reaction mechanism for the Tetraethoxysilane (TEOS) thermal decomposition at atmospheric pressure, its pertinent elemental reactions involving the SiO(OC2H5)(2) reaction intermediate were first proposed. For respective species formed in these elemental reactions, the total energy and the electronic state were calculated using a semi-empirical molecular method. The adsorption process which involves adsorbent species formation and surface reaction mechanism were then analyzed from the standpoint of molecular orbital formation and charge transfer mechanism, and the results are summarized as follows:
    (1)! A reaction intermediate, SiO(OC2H5)(2)((1)A(1)), is probably formed through the following p-elimination reaction route: Si(OC2H5)(4)((1)A(1)) --&gt; SiO(OC2H5)(2)((1)A(1))+C2H4((1)A(1)) +C2H5OH((1)A(1))
    (2) The adsorption of SiO(OC2H5)(2)((1)A(1)) on SiO2 occurs with charge transfer from the dangling bond of silicon atom at an active site of the SiO2 surface to the pi*-LUMO unoccupied orbital of SiO(OC2H5)(2)((1)A(1)).
    (3) The sequence of surface reactions is considered as follows:
    (1) First, a dissociation reaction of C2H5((2)A') takes place, whereby producing a double bond between silicon atom and oxygen atom of the intermediate, since they possess unpaired electrons.
    (2) Si-O bond is successively formed following the mechanism similar to the one operating in the adsorption of SiO(OC2H5)(2)((1)A(1)) on SiO2.
    (3) Electronic state of the reactant finally formed is in the (1)A(1) state, which has a sigma-orbital to be fully occupied with electrons.

    DOI

  • Prediction of pressure dependent rate constant for the reaction, SiH4(g)-&gt; SiH3(g)+H(g), using RRKM theory aided by ab-initio MO

    N Saito, M Hirota, T Ishizaki, A Fuwa

    JOURNAL OF THE JAPAN INSTITUTE OF METALS   63 ( 4 ) 520 - 526  1999.04

     View Summary

    The pressure dependent rate constant for the reaction, SiH4 (g) --&gt;SiH3 (g) + H, has been unknown from the standpoints of both experiment and calculation. It is the basic data of the reaction path analysis for RPT (Reduced Pressure Thermal)-CVD from silane, and hence it is a valuable piece of information in science and technology in view of the reaction control. In this study, the pressure dependent rate constant was predicted using the RRKM theory aided by Ab-initio MO. It was calculated under conditions in which the temperatures were from 600 to 1500 K at intervals of 100 K, the pressures were 135.32 x 10(10), 133.32 x 10(8), 133.32 x 10(6), 133.32 x 10(4), 101.32 x 10(3), 133.32 x 10(2), 133.32 x 10(1), 133.32 x 10(0), 133.32 x 10(-1),133.32 x 10(-2) and 133.32 x 10(-3)(Pa), and the third body was argon gas. The Arrhenius type rate expression was shown as follows:
    k(133.32 x 1010) = 1.94 x 10(16) exp (-45316/T) =k(high)
    k(133.32 x 108) = 1.93 x 10(16) exp (-45316/T), k(133.32 x 106) = 1.22 x 10(16) exp (-44990/T),
    k(133.32 x 104) = 9.25 x 10(14) exp (-43412/T), k(101.32 x 103) = 9.27 x 10(13) exp (-42406/T),
    k(133.32 x 102) = 1.28 x 10(13) exp (-41909/T), k(133.32 x 101) = 1.31 x 10(12) exp (-41752/T),
    k(133.32 x 100) = 1.29 x 10(11) exp (-41717/T), k(133.32 x 10-1) = 1.28 x 10(10) exp (-41708/T),
    k(133.32 x 10-2) = 1.27 x 10(9) exp (-41704/T), k(133.32 x 10-3) = 1.27 x 10(8) exp (-41704/T).
    Here, the subscript of k stands for the pressure.

    DOI

  • Prediction of Elementary Reaction Mechanism for the CVD Process in Si2Cl6-H2 System using Semi-Empirical Molecular Orbital Method

    Nagahiro Saito, Akio Fuwa

    Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals   63 ( 3 ) 319 - 325  1999

     View Summary

    From our previous experimental study of the Si chemical vapor deposition in Si2Cl6-H2 system, the following elementary reaction mechanism was proposed: decomposition of Si2Cl6 to produce SiCl2, which becomes the adsorbent
    Si2Cl6(g) → 2SiCl3(g) → SiCl4(g) + SiCl2(g) (→ SiCl2(a)), and hydrogen reduction reaction of the absorbed SiCl2 to produce Si(s). The preliminary quantum chemistry study for this reaction mechanism has shown that the reaction is so infeasible that the above-mentioned elementary reaction mechanism is unreasonable. The most feasible and appropriate reaction mechanism has been shown as follows: (Step 1) Si2Cl6(g) → SiCl4,(g) + SiCl2(g) (Step 2) SiCl2(g) +a → SiCl2(a) (Step 3) SiCl2(a) + H2(g) → SiCl(a) + 2HCl(g) (Step 3-1) SiCl2(a) + H2(g) → Si-2HCl(a) (Step 3-2) Si-2HCl(a) → Si(a) + 2HCl(g) where, a is the active site on silicon surface. On the assumption that step 3 is the rate-determining step, this elementary reaction mechanism can explain the experimental observation in the rate expression on the concentration dependence with respect to Si2Cl6 and H2.

    DOI

  • 半経験的分子軌道法によるSi2Cl6-H2系CVD反応の素過程の予測

    斉藤永宏, 不破章雄

    日本金属学会誌   63 ( 3 ) 319 - 325  1999

    DOI

  • Thermodynamic function derivation of dioxin substances using semi-empirical molecular orbital theory

    N Saito, A Fuwa

    REWAS'99 GLOBAL SYMPOSIUM ON RECYCLING, WASTE TREATMENT AND CLEAN TECHNOLOGY VOLUME I-III   3   2009 - 2018  1999

     View Summary

    In this investigation, respective thermodynamic parameters of heats of formation, standard entropy and specific heat capacity at constant pressure for PCDDs, PCDFs, Co-PCB and PCBs as well as polychlorinated-benzens and polychlorinated-phenols have been evaluated by quantum chemical calculation using a semi-empirical molecular orbital method with the PM3 Hamiltonian and statistical thermodynamic correlation The values of heats of formation for the dioxin substances and their precursors are calculated in the range of +/- 200 kJ/mol. The tolerance analysis indicates that the maximum discrepancy with experimental values would be reasonably estimated to be +/- 28 kJ/mol. The values of standard entropy for these compounds would be in the range of + 270 to + 500 kJ/mol K, and the estimated discrepancy between the calculated and experimental heats of formation would be in the range of + 1 to + 9 J/mol K.

  • CVD法における律速過程の析出速度への影響

    日本金属学会    1998

  • SiF4-NH3系熱CVD法における気相での反応性

    斉藤剛, 谷口徹, 不破章雄

    Bulletin of the Center for Informatics/Waseda University   21   74 - 76  1997

  • 小型発熱電球内部における熱および物質移動機構の数値解析

    証明学会誌/照明学会   20;2  1997

  • 解いてわかる材料工学

    丸善    1997

  • 無鉛はんだ合金開発における計算状態図の適用

    日本金属学会    1997

  • RRKM理論を用いたSi2Cl6-H2系気相熱分解の速度定数の計算

    計算化学討論会    1997

  • Quantum-RRKM理論によるSi2Cl6-H2系の気相熱分解に関する研究

    日本金属学会    1997

  • プラズマアーク放電における導電性流体特性の数値解析

    照明学会    1997

  • 水素貯蔵合金LaNi5の水素化、脱水素化における反応機構

    日本金属学会    1997

  • Ti上へのCu電析

    資源・素材学会    1997

  • CVD法によるシリコン析出のシュミレーション

    日本金属学会    1997

  • Si2Cl6=SiCl4+SiCl2、Si2Cl6=SiCl3+SiCl3の熱分解反応のRRKM理論による速度定数の理論的予測

    情報科学討論会    1997

  • アルミニウム薄膜・金バルク拡散対における相成長ならびに微量カリシウムの相成長への応用

    日本金属学会誌/日本金属学会   60;1  1996

    DOI

  • 分子軌道法を用いたSiCl4-H2反応経路の解析研究

    Bulletin of the Center for Informatics/Waseda University   18;1  1996

  • Si2Cl6から析出させたシリコン薄膜の結晶構造

    加藤慶信, 斉藤永広, 不破章雄

    日本金属学会誌/日本金属学会   60 ( 6 ) 744 - 750  1996

    DOI

  • 大気圧質量分析器によるテトラエトキシシラン熱分解反応

    日本金属学会誌/日本金属学会   60;6  1996

    DOI

  • 上吹きガスジェットによるキャビテイの形成およびスプラシュ発生に関するエネルギー収支解析

    資源と素材/資源素材学会   111;7  1996

    DOI

  • 1000K-1300KにおけるSiCl2(g)およびSiCl3(g)のGibbsの標準生成自由エネルギー変化

    金森賢樹, 杉浦正仁, 不破章雄

    日本金属学会誌   59  1995

    DOI

  • 分子軌道法を用いたSiCl4-H2の反応経路の解析研究

    Bull. Cent. for Informatics, Waseda Univ./情報科学研究教育センター   18  1995

  • Mathematical Modeling and Simulation of ISP Blast Furnace

    Zinc and Lead 95/MMIJ and TMS    1995

  • Energy Balance Analysis on Formation of Cavity and Splashing by Top-Blown Gas Injection

    Met. Rev. MMIJ/資源素材学会   12;2  1995

  • 熱CVDにおける熱力学、相図及び移動速度論的解析

    不破章雄

    資源処理技術   41 ( 4 ) 184 - 189  1994

    DOI CiNii

  • SiHCl3からのシリコン析出速度

    杉浦正仁, 不破章雄

    日本金属学会誌   58  1994

    DOI

  • Growth of Gold Plating Film on Various Nickel Substrates.

    HIRAI Kazumasa, FUWA Akio

    Jitsumu Hyomen Gijutsu   43 ( 9 ) 868 - 872  1992

     View Summary

    The effect of the crystal structure of various nickel substrates on the orientation of plated gold films was studied. The gold plating was conducted in a solution primarily composed of gold potassium cyanide at 338K and pH=6.5 with a current density of 5mA/cm2. It was found that the crystal structure of the nickel substrate influenced the orientation of the gold film as follows: (i) for films thinner than 0.2μm, there was epitaxial growth of gold film on the nickel substrate as (111)Au||(111)Ni, (200)Au||(200)Ni and (220)Au||(220)Ni: (ii) for films between 0.2 and 3μm, there was growth of the (110) plane of gold on the nickel substrates; and (iii) for films thicker than 3μm, the growth plane orientations were (111)>(220)>(200), which is considered the characteristics of gold plating under these condition.

    DOI CiNii

  • 最近の乾式製錬の進歩と展望

    不破章雄, 杉浦正仁

    資源と素材   108 ( 2 ) 87 - 94  1992

    DOI CiNii

  • 純銅の陽極反応におけるケミカルインピーダンス測定

    高田雄京, 不破章雄

    資源と素材   107 ( 9 ) 652 - 657  1991

    DOI CiNii

  • 多元系平衡状態図の計算機による作成―Si-N-Cl-H系、Si-C-Cl-H系、Al-N-Cl-H系の状態図のSi3N4, SiC, AlNの製造への応用

    不破章雄

    資源と素材   105  1989

    DOI

  • 薄膜材料素材製造

    沖猛雄, 不破章雄

    資源と素材   105 ( 2 ) 113 - 122  1989

    DOI CiNii

  • 硫酸水溶液中における銅フェライトの溶解挙動に関する研究

    Rudi Subagja, 不破章雄

    資源と素材   105 ( 1 ) 49 - 54  1989

    DOI CiNii

  • 微小交流4端子法によるFeO-Fe2O3-SiO2系スラグ融体の導電率測定

    不破章雄, 別所誠

    日本鉱業会誌   104  1988

    DOI

  • 銅陽極凝固組織と不働態化現象に及ぼす不純物元素の影響―Cu-O-5b(As, Sb, Bi)系,Cu-S-5b(As, Sb, Bi)系

    高田雄京, 不破章雄

    日本鉱業会誌   104  1988

    DOI

  • 粗銅の不働態化現象と陽極凝固組織の関連性に関する研究

    高田雄京, Rudi Subagja, 不破章雄

    日本鉱業会誌   104  1988

    DOI

  • 気体輸送法―質量分析計システムによるGeS, SnSおよびCdSの蒸気圧測定

    中村真一, 不破章雄

    日本金属学会誌   51  1987

    DOI

  • 気体輸送法―質量分析計システムの開発

    中村真一, 不破章雄

    早稲田大学理工学研究所報告   114  1986

  • 気体輸送法―質量分析法の開発とその亜鉛蒸気圧測定への応用

    不破章雄, 菅原憲次, 加藤栄

    日本金属会誌   48  1984

    DOI

  • 溶融銅マットの電気伝導度測定

    不破章雄, 山本泰然

    日本鉱業会誌   100  1984

    DOI

▼display all

 

Internal Special Research Projects

  • 溶融金属小滴の生成と金属チタン製錬への応用

    2008  

     View Summary

    近年、金属チタンはその優れた特徴により需要、用途が急速に拡大している。金属チタンの生産はクロール法で行われており、チタン原料(ルチル鉱等)の塩化工程、マグネシウム還元工程、塩化マグネシウム電解工程から構成されている。還元工程はバッチ式であり、金属チタン製錬における隘路となっており、クロール法に替わる新プロセスが望まれている。本研究課題では、ルチル(TiO2)の炭素還元により得た[TiC-TiO]固溶体を溶解性アノード(陰極)とし、溶融NaCl-KCl-TiCl2浴を用いて、カソード(陽極)に金属Tiを析出せしめる電解精製採取法を考える。[TiC-TiO]固溶体のアノード反応(Tiイオンの溶解、CO発生)は、反応性溶解反応として学術的な意義があり、同様な電解精製採取法の基礎となる重要なものとなる。本研究課題での総括反応式は、次式で表すことができ、その中間生成物は[TiC-TiO]固溶体であり、電気化学的なエネルギーも利用する画期的な還元プロセスである:2 TiO2(s)+ 4 C(s) =2 Ti(s) + 4 CO(g)。 本課題の目的は、TiO2の炭素還元反応による[TiC-TiO]固溶体の生成反応に関する諸条件(温度、時間、炭素混合比、雰囲気)を明らかにする。実験研究の結果は次の通りである:(1)TiC-TiO固溶体は、化学量論混合比のルチル、炭素の合成反応式、2 TiO2(s)+ 4 C(s) = 2 [TiC-TiO] (s) + 2 CO(g)、により生成可能であること、(2)適切な合成反応温度、時間は、それぞれ、1400C、4時間であること、(3)TiC-TiO固溶体の格子定数は従来の研究結果と同等であること。 本研究の結果、「チタン電解精製採取法」の基本となる中間原料である[TiC-TiO]固溶体の生成プロセス条件が明らかになり、重要な知見が得られた。学会発表予定:資源素材学会、研究成果発表:2010年春期大会

  • 溶融マグネシウム小滴還元反応による新チタン製錬法の基礎研究

    2007  

     View Summary

    現在、金属チタンは、900度(C)程度の高温度での四塩化チタン気体の溶融マグネシュウム還元により製造されている。この反応形態は、気体ー固体反応であり、この反応の促進には反応界面積に拡大が有効である。この課題では、溶融マグネシュウム小滴生成の基礎的な知見を得るために、液体物性(密度、粘性係数、表面張力)の異なる液体(水、グリセリン、エタノール)を用いて、各種形状のノズルを用いて、液体小滴の生成条件の実験による調査研究を行った。その結果、マグネシウム小滴生成に求められるノズル速度条件を見出すことができ、今後の展開の基礎的なデータを得ることが出来た。

  • 複合反応場を用いるイオン導伝性薄膜形成の研究

    2000  

     View Summary

    イットリア安定化ジルコニウム電解質の作成を、イットリア、ジルコニウムの有機金属を酸素プラズマ中で行った。燃料電池として作動する組成、8%Y2O3-ZrO2の作成条件を見出し、薄膜の電解質を得ることが出来た。電解質の膜厚に関する最適な値についても検討を加えた。