Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Tetsuya Okuyama Last modified date:2024.07.09

Professor / Department of Collaborative Interdisciplinary Engineering Sciences / Department of Collaborative Interdisciplinary Engineering Sciences / Faculty of Engineering Sciences

1. 松嶋 茂憲, 小林 健吉郎, 岡田 元次, 奥山 哲也, SiO_2スパッタ薄膜中に分散したCu粒子のTEM観察, 日本セラミックス協会学術論文誌 : Nippon Seramikkusu Kyokai gakujutsu ronbunshi, 10.2109/jcersj.102.299, 102, 1183, 299-300, 1994.03, Cu doped SiO_2 films have been prepared on quartz sub strates by an RF magnetron sputtering method. An as sputtered film showed no renection peaks in the X-ray diffraction pattern. Results of TEM observations of the as sputtered film indicated that Cu particles have a mean size of ca. 8.0 nm, and that they were dispersed homogeneously in Si0_2・ Some reflection peaks ap peared in X-ray diffraction pattern of a Cu doped SiO_2 film heated at 600℃. Heating at 600℃ increased the mean size of Cu particles slightly..
2. Wire Explosion Thermal Sprayed Coatings of Ni-P Alloy-Plated SUS304 Wires.
3. T Okuyama, M Nakayama, Y Tomokiyo, O Van der Biest, Strain analysis of Si by FEM and energy-filtering CBED, MICROSCOPY AND MICROANALYSIS, 10.1017/S1431927601010030, 8, 1, 11-15, 2002.02, Lattice strains around a platelet oxygen precipitate in Si wafer is studied by energy filtering convergent-beam electron diffraction (CBED) and calculations based on the finite element method (FEM). Local lattice strains are measured from CBED patterns obtained with a probe size less than 2 nm in a specimen thicker than 450 nm. Strains measured are compressive along a direction normal to a plate of the precipitate and tensile along a direction parallel to the plate. Two-dimensional stress fields near the precipitate are obtained with FEM computer analyses by fitting the measured strains. It appears that shear stresses are concentrated at the end of the precipitate edge and the maximum shear stress at an interface between the precipitate and the Si-matrix is 1.9 GPa. It is demonstrated that a combination of the energy filtering CBED and FEM is very useful for the study of local strains near interfaces in semiconductor devices, in particular for the study of stress fields that are too steep for application of the conventional CBED technique..
4. Measurements of local lattice strains by convergent-beam electron diffraction.
5. Characterization of Wire Explosion Thermal Sprayed Ni-P/SUS304 Composite Coatings.
6. Preparation of Alloy Wires for Amorphous Coatings by Wire Explosion Thermal Spraying Process and Formation of Coatings.
7. Characteristics of ti-1mass%sc powder prepared by mechanical alloying process masaru nakayama
Ti-1mass%Sc mixed powder was milled up to 240 h in argon gas atmosphere in a stainless pot with stainless steel balls. Pure Ti powder and Ti-20mass%Sc mixed powder were used as comparing materials. Mean particle sizes of MA powders increased with increasing MA time up to 72 h and decreased with increasing MA time in the time more than 72 h. The mean particle size of pure Ti powder milled for 240 h was approximately 30 μm to 30 μm before milling. On the other hand that of Ti-1mass%Sc powder was approximately 10 μm to 20 μm before milling. In both pure Ti and Ti-1mass%Sc powder, the particles were hardened gradually with increasing MA time. The hardness of particles of pure Ti and Ti-1 mass%Sc powders was approximately HV500 at the time of 240 h to HV150 before milling. It was clarified that Sc was distributed uniformly in the particles after milled at 120h in Ti-20mass%Sc mixed powder. The particles of powders milled were maintained very high hardness even after heated for 1h at 1273 K. The hardness of sintered body was very high and approximately HV500..
8. Analysis of Local Stress Distribution in Si Wafer by Combination Technique of CBED and FEM.
9. Kiyoshi Matsuyama, Neil Ihsan, Keiichi Irie, Kenichi Mishima, Tetsuya Okuyama, Hiroyuki Muto, Bioimaging application of highly luminescent silica-coated ZnO-nanoparticle quantum dots with biotin, Journal of Colloid and Interface Science, 10.1016/j.jcis.2013.02.047, 399, 19-25, 2013.06, We synthesized ZnO-nanoparticle quantum dots (QDs) as a fluorescent probe for biological applications. Highly luminescent silica-coated ZnO-nanoparticle QDs dispersed in an aqueous medium were synthesized using the sol-gel process. The ZnO-nanoparticle QDs were coated with silica to improve the water stability of the ZnO nanoparticles. NH2 groups were introduced on the surface of the silica-coated ZnO-nanoparticle QDs first by the addition of 3-aminopropyltrimethoxysilane and then by biotinylation with sulfosuccinimidyl-6-(biotin-amido) hexanoate (sulfo-NHS-LC-bioton). We demonstrated that avidin-immobilized agarose beads were tagged by the silica-coated ZnO-nanoparticle QDs with biotin by the selective avidin-biotin interaction, furnishing a fluorescent image upon excitation with UV light. Furthermore, use of the silica-coated ZnO-nanoparticle QDs with biotin in cell-labeling applications was attempted, and attachment of the silica-coated ZnO-nanoparticle QDs with biotin to nerve cells and actin filaments was achieved. © 2013 Elsevier Inc..
10. Supercritical carbon dioxide-assisted drug loading and release from biocompatible porous metal-organic frameworks
© The Royal Society of Chemistry 2014.Herein we describe the supercritical carbon dioxide (scCO2)-assisted drug loading and release from nontoxic and biocompatible porous iron(III) polycarboxylate metal-organic frameworks (MOFs), which exhibited very high cargo loadings and gradual release. MIL-53(Fe) and MIL-100(Fe) were investigated as potential carriers for drug molecules, using ibuprofen as a model drug candidate. The loading and release behaviour of ibuprofen were monitored by thermogravimetric analyses (TGA) and high performance liquid chromatography (HPLC) measurements to quantitatively determine the ibuprofen uptake, and have been performed for the first time using scCO2-based technology. After the preparation of the MOFs within a particular solvent, the internal surface area of MIL-53(Fe) and MIL-100(Fe) increased as a result of the scCO2 drying method. Furthermore, ibuprofen could be impregnated into the pores of the MOFs by utilizing a scCO2-hexane solution. ScCO2-assisted impregnation could also be used to deliver ibuprofen to the pores of the MOFs. As a result, a large amount of ibuprofen was able to be loaded into MIL-53(Fe) and MIL-100(Fe)..
11. Matsuyama K, Tanaka S, Okuyama T, Hydrophobic modification of fibers by pressure-induced phase-separation coupled with ultrasonic irradiation in high-pressure liquid carbon dioxide, Chemical Engineering Journal, 10.1016/j.cej.2014.02.055, 246, 106-113, 2014.06.
12. Kiyoshi Matsuyama, Yu-ki Maeda, Takaaki Matsuda, Tetsuya Okuyama, Hiroyuki Muto, Formation of poly(methyl methacrylate)-ZnO nanoparticle quantum dot composites by dispersion polymerization in supercritical CO2, JOURNAL OF SUPERCRITICAL FLUIDS, 10.1016/j.supflu.2015.04.025, 103, 83-89, 2015.08, Poly(methyl methacrylate) (PMMA)-ZnO nanoparticle quantum dot (QD) composites were synthesized by dispersion polymerization in supercritical CO2 using poly(dimethylsiloxane)-g-pyrrolidonecarboxylic acid as a stabilizer. The ZnO nanoparticle QDs were first coated with silica to improve the stability of the ZnO nanoparticles in the methyl methacrylate (MMA) monomer and supercritical CO2. Vinyl groups were then introduced onto the surface of the silica-coated ZnO nanoparticle QDs by the addition of 3-(trimethoxysilyl)propylmethacrylate (TPM). These groups helped to minimize the QD loss during the formation of the PMMA and ZnO nanoparticle QD composite. The PMMA-ZnO QD composites were dissolved into tetrahydrofuran and transparent polymeric hybrid films of ZnO nanoparticle QDs and PMMA were obtained after evaporation of the THF from the solution. The unmodified ZnO nanoparticle QDs, which were agglomerated in the PMMA matrix, and the well-dispersed silica-coated ZnO nanoparticle QDs coupled with TPM exhibited weak and high emissions, respectively under UV irradiation. The silica layer and TPM stabilized the ZnO nanoparticle QDs. TPM promotes compatibility between the QDs and the PMMA matrix. (C) 2015 Elsevier B.V. All rights reserved..
13. Higashizono T, Kuan N. K, Okuyama T, Effect of Nb and W addition on heat-resistance of austenitic cast steel, 72nd World Foundry Congress ( WFC2016 ), P32, 2016.05.
14. Kiyoshi Matsuyama, Momoe Motomura, Takafumi Kato, Tetsuya Okuyama, Hiroyuki Muto, Catalytically active Pt nanoparticles immobilized inside the pores of metal organic framework using supercritical CO2 solutions, MICROPOROUS AND MESOPOROUS MATERIALS, 10.1016/j.micromeso.2015.12.005, 225, 26-32, 2016.05, Pt nanoparticles were successfully immobilized inside the pores of a metal organic framework (MOF) like MIL-101(Cr) using supercritical carbon dioxide (scCO(2)), without Pt nanoparticles aggregating on the external surfaces of framework. After its preparation in a particular solvent, the internal surface area of MIL-101(Cr) increased slightly due to the scCO(2) drying method. The precursor H2PtCl6 could also be impregnated into the MOF pores using a scCO(2)-ethanol solution. These synthesized samples were reduced by treating in a stream of H-2 at 473 K. During the reduction, the formed Pt nanoparticles get dispersed within the MIL-101(Cr). TEM images clearly demonstrate the uniform three-dimensional distribution of Pt nanoparticles in the interior cavities of MIL-101(Cr). The resulting Pt@MIL-101(Cr) composites represent the highly active MOF-immobilized metal nanocrystals for catalytic ammonia borane hydrolysis. (C) 2015 Elsevier Inc. All rights reserved..
15. Synthesis of C12A7 powder by using complex homogeneous precipitation method.
16. Kiyoshi Matsuyama, Shota Tanaka, Takafumi Kato, Tetsuya Okuyama, Hiroyuki Muto, Riichi Miyamoto, Hong-zhi Bai, Supercritical fluid-assisted immobilization of Pd nanoparticles in the mesopores of hierarchical porous SiO2 for catalytic applications, JOURNAL OF SUPERCRITICAL FLUIDS, 10.1016/j.supflu.2017.07.032, 130, 140-146, 2017.12, Pd nanoparticles were successfully immobilized in the mesopores of hierarchical porous SiO2 and TiO2 using supercritical carbon dioxide (scCO(2))-acetone solution. The hierarchical porous SiO2 with macropores and mesopores demonstrated remarkable properties as a support for noble metal nanoparticle catalysts. The nano particle precursor, palladium(II) acetate (Pd(OAc)(2)), was impregnated into the mesopores of hierarchical porous SiO2 and TiO2 microparticles using scCO(2). These samples were subsequently reduced by treatment in a stream of H-2 at 473 K. During reduction, the formed Pd nanoparticles were dispersed within the hierarchical porous SiO2, with a uniform three-dimensional distribution of nanoparticles in the mesopores revealed by TEM images. The resulting Pd@hierarchical porous SiO2 exhibited high activity for the heterogeneous catalytic hydrogenation reaction of styrene in methanol solution. The catalytic activity of the Pd@hierarchical porous SiO2 was higher than that of Pd@conventional porous SiO2 without hierarchical porosity or the Pd@hierarchical porous TiO2..
17. Study on single-phase fabrication in ε-FeSi and crystal structure analysis.
18. Structural Analysis of NbTi/SUS304 for filter-type semi-rigid cryogenic cable.
19. Effect of ε-FeSi phase content on thermoelectric properties of β-FeSi2 compound.
20. Development of semi-rigid superconducting coaxial cables with normal-conductor-clad center conductor.
21. Okuyama T, Yokoo T, Yamasaki Y, Matsuyama K, Muto H, Study on ZrO2 nanoparticles having fluorescence property synthesized by complexing agent, Microscopy, 10.1093/jmicro/dfy120, 67, i47, 2018.10.
22. Effect of Nb on Thermal-Shock Resistance of Austenitic Heat Resistant Cast Steel.
23. T. Okuyama, A. Nakamura, K. Ohta, K. Matsuyama, H. Muto, ZnO nanoparticles with fluorescent properties suitable for modification on protein surfaces, Microscopy, 10.1093/jmicro/dfz096, 68, i42, 2019.11.
24. N.H.K. Luan, K. Koizumi, K. Mizuno, Y. Yamada, T. Okuyama, Influence of as-cast microstructure on the impact wear resistance of 27 mass%Cr cast Iron, Materials Transactions, 10.2320/matertrans.F-M2019844, 60, 11, 2475-2480, 2019.11.
25. N.H.K. Luan, K. Koizumi, K. Mizuno, Y. Yamada, T. Okuyama, Influence of As-Cast Microstructure on Impact Wear Resistance of 27mass%Cr Cast Iron, Materials Transactions, 10.2320/matertrans.F-M2019844, 60, 11, 2475-2480, 2019.10.
26. Yuki OBUKURO, Toru OKAWARA, Tetsuya OKUYAMA, First-principles study of electronic structure of Er-doped monoclinic ZrO2, Journal of the Ceramic Society of Japan, 127, 12, 958-962, 2019.12.
27. T. Yokoo, K. Nagashima, T. Yanagida, Y. Obukuro, T. Okuyama, Evaluation of crystal structure and surface-to-molecule interaction in hydrothermally grown titanium oxide nanowires, Microscopy, 10.1093/jmicro/dfz107, 68, i39, 2019.11.
28. K.-L. N.-Huynh, T. Okuyama, K. Koizumi, M. Kudo, Effect of microstructure on creep property of W-added heat resistant cast steel, Microscopy, 10.1093/jmicro/dfz094, 68, i39, 2019.11.
29. K. Matsuyama, K. Morotomi, S. Inoue, M. Nakashima, H. Nakashima, T. Okuyama, T. Kato, H. Muto, H. Sugiyama, Antibacterial and antifungal properties of Ag nanoparticle-loaded cellulose nanofiber aerogels prepared by supercritical CO2 drying, J. Supercritical Fluids, 10.1016/j.supflu.2018.08.008, 143, 1-7, 2019.01.
30. 耐熱鋳鋼のミクロ組織と高温特性に及ぼす鋳込み温度の影響.
31. Effect of W addtion on Microstructure and High Temperature Properties of Austenitic Heat Resistant Cast Steel.
32. Kiyoshi Matsuyama, Tomohiro Tsubaki, Takafumi Kato, Tetsuya Okuyama, Hiroyuki Muto, Preparation of catalytically active Au nanoparticles by sputter deposition and their encapsulation in metal-organic framework of Cu3(BTC)2, Materials Letters, 10.1016/j.matlet.2019.127124, 261, 127124-127124, 2020.02.
33. Taisei Motomura, Tatsuo Tabaru, Masato Uehara, Yuki Fujio, Tetsuya Okuyama, Low-temperature AlN film deposition using magnetic mirror-type magnetron cathode for low gas pressure operation, JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B, 10.1116/1.5129720, 38, 3, 032205-032205, 2020.05, Low-temperature aluminum nitride (AlN) depositions were studied under low gas pressure conditions of 0.1Pa. In order to operate under 0.1Pa sputter-conditions, the magnetic mirror-type magnetron cathode (M3C) has been developed in the authors' studies. The plasma light-emission distributions generated by the M3C were observed at an input RF power of 5-100W and an Ar gas pressure of 0.1-0.65Pa. The M3C can operate effectively with both low gas pressure of 0.1Pa (Ar) and low RF power of 5W. The AlN films were deposited using a bare silicon substrate without external substrate heating. Thec-axis oriented AlN film was obtained at 0.1Pa (pure nitrogen), 100W, and a target-to-substrate distance of 70mm..
34. Ngo Huynh Kinh Luan, Koreaki Koizumi, Tetsuya Okuyama, Influence of Nb and V Addition on Abrasive and Impact Wear Properties of 16%Cr–3%Mo White Cast Iron, MATERIALS TRANSACTIONS, 10.2320/matertrans.f-m2020852, 61, 12, 2363-2370, 2020.12.
35. Sho Nekita, Kazuki Nagashima, Guozhu Zhang, Qianli Wang, Masaki Kanai, Tsunaki Takahashi, Takuro Hosomi, Kentaro Nakamura, Tetsuya Okuyama, Takeshi Yanagida, Face-Selective Crystal Growth of Hydrothermal Tungsten Oxide Nanowires for Sensing Volatile Molecules, ACS APPLIED NANO MATERIALS, 10.1021/acsanm.0c02194, 3, 10, 10252-10260, 2020.10, Here, we demonstrate the impact of tungsten precursor concentration on anisotropic crystal growth of hydrothermal tungsten oxide (WO3) nanowires. When varying the tungsten precursor concentration, we found two different critical concentrations for crystal growth on the (001) top plane and (100) sidewall plane of WO3 nanowires. A (001) plane-selective crystal growth is achieved by precisely controlling the tungsten precursor concentration in between these critical concentrations, while a crystal growth on the (100) plane tends to simultaneously occur above such a concentration range. Furthermore, the crystal growth rate on the (001) plane tends to be suppressed when the number density of nanowires increases due to competitive material supply between nanowires. The observed concentration dependence on nanowire growth can be interpreted in terms of a competition between the nucleation in solution and the crystal growth on the nanowire surface. The suggested mechanism offers a rational way to precisely control the nanowire structure and the number yield of nanowires. Using a single nanowire device composed of a structurally controlled WO3 nanowire, we demonstrate highly sensitive electrical molecular sensing of nonanal at 27 ppb..
36. Tetsuya Okuyama, Takumi Higashizono, Ngo Huynh Kinh Luan, Masaki Kudo, Effect of Nb on Thermal-Shock Resistance of Austenitic Heat Resistant Cast Steel, MATERIALS TRANSACTIONS, 10.2320/, 61, 9, 1711-1716, 2020.09.
37. Kiyoshi Matsuyama, Noriyuki Tomiyasu, Kaho Inoue, Riku Yokomizo, Tetsuya Okuyama, Hiroyuki Muto, Catalytically active PdRu and CuRu bimetallic nanoparticle formation in the mesoporous SiO2 by supercritical CO2-assisted immobilization, The Journal of Supercritical Fluids, 10.1016/j.supflu.2020.104818, 160, 104818-104818, 2020.06.
38. 27%Cr鋳鉄の耐衝撃摩耗性に及ぼす鋳放し状態のミクロ組織の影響.
39. Role of Matrix Structure on Impact-wear Resistance of As-quenched 27%Cr Cast Iron.
40. Nb添加耐熱鋳鋼のミクロ組織および高温機械的特性特性に及ぼす鋳込み温度の影響.
41. Taisei Motomura, TatsuoTabaru, Yuki Fujio, Tetsuya Okuyama, Influence of nitrogen gas flow ratio on gallium nitride film growth using high-density convergent plasma sputtering device at room temperature, Journal of Vacuum Science & Technology A, 10.1116/6.0000677, 39, 1, 013001-1-013001-7, 2021.01.
42. 27%Cr鋳鉄の耐衝撃摩耗に及ぼす焼入れ温度の影響.
43. influence of Nb and V Addition on Abrasive and Impact Wear Properties of 16%Cr-3%Mo White Cast Iron.
44. nfluence of Nb Additionon Microstructure and Creep Property of Heat-Resistant Cast Steel in Vacuum Carburizing and Quenching.
45. Ngo Huynh Kinh Luan, Koreaki Koizumi, Kuniaki Mizuno, Yutaka Yamada, Tetsuya Okuyama, Masaru Nakayama, Role of Matrix Structure on Impact-Wear Resistance of As-Quenched 27%Cr Cast Iron, MATERIALS TRANSACTIONS, 10.2320/matertrans.f-m2022803, 63, 5, 740-747, 2022.05.
46. Ngo Huynh Kinh Luan, Tetsuya Okuyama, Masaru Nakayama, Kuniaki Mizuno, Koreaki Koizumi, Influence of Nb Addition on Microstructure and Creep Property of Heat-Resistant Cast Steel in Vacuum Carburizing and Quenching, MATERIALS TRANSACTIONS, 10.2320/matertrans.f-m2022810, 63, 11, 1557-1566, 2022.11.
47. Yuto Kawato, Taisei Motomura, Tatsuo Tabaru, Masato Uehara, Tetsuya Okuyama, Effect of RF power on AlN film crystallinity in low pressure range using Ar-20%N2 gases by magnetic mirror-type magnetron cathode, Japanese Journal of Applied Physics, 10.35848/1347-4065/ac4f96, 61, 4, 046001-046001, 2022.04, Abstract

Effect of radio frequency (RF) power on aluminum nitride (AlN) film crystallinity has been studied under low gas pressure of $geqslant $0.1 Pa and low RF power of $geqslant $3 W with Ar-20%N2 gas by a proposed balanced magnetron cathode with a high plasma production efficiency. The gas pressure and the RF power dependences of AlN film crystallinity show that the c-axis oriented AlN films can be obtained only at 50 W and 100 W in 0.1 Pa. The AlN film crystallinity was not promoted in the low RF power range of
48. Microstructures of SUS304 Stainless Steel after Long-Term Service in Vacuum Carburizing Quenching.
49. Kiyoshi Matsuyama, Yuka Kawahara, Ayano Shoji, Takafumi Kato, Tetsuya Okuyama, Supercritical CO2‐assisted formation of metal–organic framework‐loaded porous polystyrene membranes for dye removal, Journal of Applied Polymer Science, 10.1002/app.54347, 140, 35, 2023.07.
50. Changes in Carburized Microstructures and Creep Properties of Nb-Added SCH13A Heat-Resistant Cast Steel due to Different Pouring Temperatures.