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Onoda, Shinobu; Yamamoto, Takashi; Oshima, Takeshi; Isoya, Junichi*; Teraji, Tokuyuki*; Watanabe, Kenji*
Transactions of the Materials Research Society of Japan, 37(2), p.241 - 244, 2012/06
Yamaguchi, Kenji; Esaka, Fumitaka; Sasase, Masato*; Yamamoto, Hiroyuki; Hojo, Kiichi
Transactions of the Materials Research Society of Japan, 37(2), p.245 - 250, 2012/06
"Semiconducting silicides", such as 
-FeSi
, BaSi, MgSi, etc. are composed of elements which are non or less toxic and are naturally abundant, so that they are considered to be ecologically friendly. These materials are being investigated for applications in optoelectronics, photovoltaics, photonics, thermoelectrics, and so on. In order to fabricate silicide films on crystalline Si substrate, sputter-etching (SE) of the substrate with low energy ion beams has been successfully applied. When the conditions are met, a highly-oriented -FeSi (100) film can be grown on Si (100) substrate by means of ion beam sputter deposition method. According to cross-sectional transmission electron microscopy (TEM) observation, the interface of the SE-treated substrate and the film deposited at 973 K is smooth, although some defects are produced as a result of this treatment. On the other hand, a combination of X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) revealed that relatively homogeneous -FeSi surface is formed at this temperature. In order to further improve the film properties with smaller amount of defects, SE-treatment is performed with the ions whose incident energy is below 1 keV. X-ray diffraction (XRD) analysis confirmed that highly-oriented -FeSi (100) film can be also obtained with SE-treatment by 0.8 keV Ne
ions, as in the case of 3.0 keV Ne.
Kitamura, Akane; Sato, Takahiro; Koka, Masashi; Kamiya, Tomihiro; Kobayashi, Tomohiro*
Transactions of the Materials Research Society of Japan, 37(2), p.219 - 222, 2012/06
Yamaki, Tetsuya; Nuryanthi, N.*; Koshikawa, Hiroshi; Asano, Masaharu; Sawada, Shinichi; Hasegawa, Shin; Maekawa, Yasunari; Voss, K.-O.*; Trautmann, C.*; Neumann, R.*
Transactions of the Materials Research Society of Japan, 37(2), p.223 - 226, 2012/06
The aim of this study is to investigate the formation of the poly(vinylidene fluoride) (PVDF) track membranes in detail by electrolytic conductometry. A PVDF film was irradiated with a 450 MeV 
Xe or 2.2 GeV 
Au ion beam, and then the latent tracks were etched in a 9 mol dm
aqueous KOH solution at 80
C that had been poured into a conductometric cell. At the same time, the evolution of cylindrical nanopores was monitored by measuring the conductance through the membrane. The etching kinetics significantly depended on the deposited energy within each track, which is represented by the LET. Interestingly, applying a higher voltage to the cell promoted track etching up to the breakthrough probably because the electrophoretic migration of dissolved products occurred out of each pore.
Takano, Katsuyoshi*; Sugimoto, Masaki; Asano, Atsushi*; Maeyoshi, Yuta*; Marui, Hiromi*; Omichi, Masaaki*; Saeki, Akinori*; Seki, Shu*; Sato, Takahiro; Ishii, Yasuyuki; et al.
Transactions of the Materials Research Society of Japan, 37(2), p.237 - 240, 2012/06
phases using high-energy X-ray diffractionYoneda, Yasuhiro; Yoshii, Kenji; Kohara, Shinji*
Transactions of the Materials Research Society of Japan, 37(1), p.73 - 76, 2012/03
The structures and phase transitions of AgNbO were investigated using high-energy X-ray powder diffraction. Bragg reflections have revealed the high temperature M-O, O-T, and T-C phase transitions but have not given any significant evidence of low temperature M
-M and M-M ones. The existence of structural disorder in the T and O phases was indicated by diffuse scattering. Here we again confirm the average structure of AgNbO. The refined structure was essentially the same as previous reports. With isotropic thermal parameters, refinements of the structures at most temperatures resulted in larger Ag thermal parameters. Disorder feature of Ag coupled with the thermal parameters and exhibit as diffuse scattering in T and O phases.
Johnson, B. C.; Sato, Shinichiro; Oshima, Takeshi; Simpson, D. A.*
no journal, ,
Yamashita, Shinichi; Hiroki, Akihiro; Nagasawa, Naotsugu; Taguchi, Mitsumasa
no journal, ,
We developed a polymer gel dosimeter with low toxicity by employing a cellulose derivative, hydroxypropyl cellulose, as a base matrix, 2-hydroxyethyl-methacrylate as a polymerizing monomer, polyethylene glycol ester dimethacrylate as a crosslinker, and tetrakis (hydroxymethyl)phosphonium chloride as an oxygen scavenger. The gel dosimeter was irradiated with 
Co 
-rays at dose rate of 3-8 Gy/h, resulting in visual change from transparent to white cloud-like state. The irradiated dosimeters were analyzed by UV-vis spectrometry and measurement of haze, which is defined as the ratio of diffractive transmission to sum of diffractive and parallel transmissions. There is no obvious difference in UV-vis spectra among the dosimeters with different compositions. No peak but a broad and downward curve was observed in wavelength from 300 to 800 nm. This would be attributed to scattering by microgel of polymerized solutes or to chemical bonds produced during the polymerization. Haze almost monotonically increases with increasing -dose although difference at low dose region (smaller than 1 Gy) was difficult to be quantitatively identified.
ionsNarumi, Kazumasa; Naramoto, Hiroshi*; Yamada, Keisuke; Chiba, Atsuya; Saito, Yuichi; Takahashi, Yasuyuki*; Maeda, Yoshihito
no journal, ,
Hiroki, Akihiro; Shirotani, Rumiko*; Suzuki, Masashi*; Taguchi, Mitsumasa; Tamada, Masao
no journal, ,
no abstracts in English
Yamaguchi, Daisuke; Koizumi, Satoshi; Hasegawa, Yoshio*; Hishinuma, Yukio*; Suzuki, Masashi*; Kodama, Hiroto*; Onuma, Masato*; Oba, Yojiro*
no journal, ,
Among the wide variety of photo-catalytic products titanium dioxide (TiO
)) is one of the most promising material and various improvement has been attempted. Recently it has been confirmed that the nitrogen (N)-doped TiO can be activated not only by ultraviolet light but also by visible light and thereby an enhancement of the efficiency is attained. However, the difference in structure between bare TiO and N-doped one has not yet been fully clarified despite the considerable structural analyses by using X-ray diffraction (XRD) or microscopy. In this study the structure of N-doped TiO was studied by small-angle neutron (SANS) and X-ray scattering (SAXS) methods by profiting the considerable difference of the scattering contrast of N atom to the neutron and to the X-ray. The resultant SANS and SAXS profiles are different between them, especially at high q region of (q
1(nm
), where q denotes the magnitude of scattering vector. This result can be interpreted as the localization of N atoms at around the surface area.
Putra, A.; Koizumi, Satoshi; Yamaguchi, Daisuke; Zhao, Y.; Noda, Yohei; Iwase, Hiroki*
no journal, ,
Maekawa, Yasunari; Hasegawa, Shin; Chen, J.
no journal, ,
We applied the radiation-induced grafting to poly(ether ether ketone) film, which was mechanically and thermally stable aromatic hydrocarbon polymers, so-called "super engineering plastics". The developed PEEK-based polymer electrolyte membrane (PEM) with 96 
m thickness exhibited 1.5 times higher conductivity and 2.3 times higher mechanical strength, compared with conventional fluorinated PEM. According to the high mechanical strength of PEEK substrates, we could reduce the film thickness of PEEK-based PEM down to 10 m. The PEEK-based PEM with film thickness of 10 and 19 m showed higher cell voltages than that of Nafion at the current density. The high mechanical and thermal properties were well explained by the hierarchical structures of the membranes using small angle X-rays/neutron scattering experiments.
