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Journal Articles

X-ray and neutron study on the structure of hydrous SiO$$_{2}$$ glass up to 10 GPa

Urakawa, Satoru*; Inoue, Toru*; Hattori, Takanori; Sano, Asami; Kohara, Shinji*; Wakabayashi, Daisuke*; Sato, Tomoko*; Funamori, Nobumasa*; Funakoshi, Kenichi*

Minerals (Internet), 10(1), p.84_1 - 84_13, 2020/01

 Times Cited Count:0

The structure of hydrous amorphous SiO$$_{2}$$ is fundamental to investigate the effects of water on the physicochemical properties of oxide glasses and magma. The hydrous SiO$$_{2}$$ glass with 13 wt.% D$$_{2}$$O was synthesized under high-pressure and high-temperature conditions and its structure was investigated by small angle X-ray scattering, X-ray diffraction, and neutron diffraction experiments at pressures of up to 10 GPa and room temperature. This hydrous glass is separated into a SiO$$_{2}$$ rich major phase and a D$$_{2}$$O rich minor phase. Medium-range order of the hydrous glass shrinks compared to the anhydrous SiO$$_{2}$$ glass due to disruption of SiO$$_{4}$$ linkage by formation of Si-OD deuterioxyl, while the pressure response is similar. Most of D$$_{2}$$O molecules are in the small domains and hardly penetrate into SiO$$_{2}$$ major phase.

Journal Articles

Strain measurement in Ti layers of CFRP/Ti laminates by synchrotron X-ray diffraction

Akita, Koichi; Nakatani, Hayato*; Ogihara, Shinji*; Shobu, Takahisa; Shiro, Ayumi*; Igawa, Naoki; Shimojo, Yutaka

SPring-8/SACLA Riyo Kenkyu Seikashu (Research Report) (Internet), 6(1), p.105 - 108, 2018/01

no abstracts in English

Journal Articles

Local structure analysis of (Na$$_{0.5}$$K$$_{0.45}$$Li$$_{0.05}$$)NbO$$_3$$ synthesized by malic acid complex solution method

Yoneda, Yasuhiro; Takada, Eri*; Nagai, Haruka*; Kikuchi, Takeyuki*; Morishita, Masao*; Kobune, Masafumi*

Japanese Journal of Applied Physics, 56(10S), p.10PB07_1 - 10PB07_7, 2017/10

 Times Cited Count:2 Percentile:76.98(Physics, Applied)

A monoclinic phase was discovered in (Na$$_{0.5}$$K$$_{0.45}$$Li$$_{0.05}$$)NbO$$_3$$ solid solution ceramics grown by a malic acid complex solution method. The average and local structures of this monoclinic phase were analyzed by synchrotron X-ray measurements. The local structure can be reproduced by assuming a rhombohedral model, that is the same local structure of KNbO$$_3$$. The results demonstrate that the monoclinic average structure is observed as a disordered rhombohedral structure.

Journal Articles

Local deformation analysis in martensite layer of high-strength multilayered steel composite using synchrotron X-ray diffraction

Ojima, Mayumi*; Shiro, Ayumi*; Suzuki, Hiroshi; Inoue, Junya*; Shobu, Takahisa; Xu, P. G.; Akita, Koichi; Nambu, Shoichi*; Koseki, Toshihiko*

Zairyo, 66(6), p.420 - 426, 2017/06

Journal Articles

Recent progress of line-profile analyses for neutron or X-ray diffraction

Tomota, Yo*; Sato, Shigeo*; Harjo, S.

Tetsu To Hagane, 103(2), p.73 - 85, 2017/01

 Times Cited Count:7 Percentile:34.77(Metallurgy & Metallurgical Engineering)

Journal Articles

Quantitative analysis of tempering microstructure via ${it in-situ}$ synchrotron X-ray diffraction during heating

Morooka, Satoshi; Kanata, Hiroyuki*; Oba, Yojiro*; Sato, Masugu*

Heisei-28-Nendo SPring-8 Sangyo Shinbunya Shien Kadai, Ippan Kadai (Sangyo Bunya) Jisshi Hokokusho, p.95 - 98, 2017/00

no abstracts in English

Journal Articles

Presence of $$varepsilon$$-martensite as an intermediate phase during the strain-induced transformation of SUS304 stainless steel

Hatano, Masaharu*; Kubota, Yoshiki*; Shobu, Takahisa; Mori, Shigeo*

Philosophical Magazine Letters, 96(6), p.220 - 227, 2016/06

 Times Cited Count:5 Percentile:51.98(Materials Science, Multidisciplinary)

We have investigated the formation process of $$alpha$$'-martensite from the $$gamma$$-phase induced by external strain using in-situ synchrotron diffraction experiments, combined with Lorentz transmission electron microscopy (TEM) and high-resolution TEM observations. It is clearly demonstrated that $$varepsilon$$-martensite with hexagonal symmetry appears as an intermediate structure during the plastic deformation of SUS304 stainless steel. In addition to stacking faults and dislocations, interfaces between the twin structures presumably play a key role in the formation of $$varepsilon$$-martensite.

Journal Articles

Negative correlation between electrical response and domain size in a Ti-composition-gradient Pb[(Mg$$_{1/3}$$Nb$$_{2/3}$$)$$_{1-x}$$Ti$$_{x}$$]O$$_{3}$$ crystal near the morphotropic phase boundary

Shimizu, Daisuke*; Tsukada, Shinya*; Matsuura, Masato*; Sakamoto, Junya*; Kojima, Seiji*; Namikawa, Kazumichi*; Mizuki, Junichiro; Owada, Kenji

Physical Review B, 92(17), p.174121_1 - 174121_5, 2015/11

 Times Cited Count:7 Percentile:54.93(Materials Science, Multidisciplinary)

The phase diagram and the relationship between the crystal coherence length and electrical response of Pb[(Mg$$_{1/3}$$Nb$$_{2/3}$$)$$_{1-x}$$Ti$$_{x}$$]O$$_{3}$$ (PMN-xPT) near the morphotropic phase boundary (MPB) have been precisely investigated using a single crystal with a Ti composition gradient by synchrotron X-ray diffraction and inelastic light scattering at room temperature. The crystal has two boundaries at Ti compositions of 29.0 mol% and 34.7 mol% which correspond to the phase boundaries between the monoclinic B (MB) and C (MC) phases and between the MC and tetragonal (T) phases, respectively. It is shown that there is a strong negative correlation between the electrical response and the crystal coherence length at the sub-$$mu$$m scale. The results are explained by the size effects of domains near the MPB.

Journal Articles

Direct observation of lattice symmetry breaking at the hidden-order transition in URu$$_2$$Si$$_2$$

Tonegawa, Sho*; Kasahara, Shigeru*; Fukuda, Tatsuo; Sugimoto, Kunihisa*; Yasuda, Nobuhiro*; Tsuruhara, Yugo*; Watanabe, Daiki*; Mizukami, Yuta*; Haga, Yoshinori; Matsuda, Tatsuma*; et al.

Nature Communications (Internet), 5, p.4188_1 - 4188_7, 2014/06

 Times Cited Count:42 Percentile:8.17(Multidisciplinary Sciences)

Journal Articles

X-ray backscattering study of crystal lattice distortion in hidden order of URu$$_2$$Si$$_2$$

Tabata, Chihiro*; Inami, Toshiya; Michimura, Shinji*; Yokoyama, Makoto*; Hidaka, Hiroyuki*; Yanagisawa, Tatsuya*; Amitsuka, Hiroshi*

Philosophical Magazine, 94(32-33), p.3691 - 3701, 2014/00

 Times Cited Count:9 Percentile:41.72(Materials Science, Multidisciplinary)

Journal Articles

Structural changes in anatase TiO$$_{2}$$ thin films irradiated with high-energy heavy ions

Ishikawa, Norito; Yamamoto, Shunya; Chimi, Yasuhiro

Nuclear Instruments and Methods in Physics Research B, 250(1-2), p.250 - 253, 2006/09

 Times Cited Count:35 Percentile:7.19(Instruments & Instrumentation)

Electronic excitation effects on TiO$$_{2}$$ thin films with anatase structure irradiated with 230MeV Xe ions have been studied by means of X-ray diffraction method. X-ray diffraction intensity shows exponential decrease as a function of ion-fluence, indicating that tracks having about 10nm diameter are introduced by the irradiation. Rutile structured TiO$$_{2}$$ was also irradiated and exhibited different damage behavior from that of anatase one. We demonstrated that X-ray diffraction meathod is one of the powerful tool to investigate track structure.

Journal Articles

Characterization of sulfur-doped TiO$$_{2}$$ films by RBS/C

Yamamoto, Shunya; Takeyama, Akinori; Yoshikawa, Masahito

Nuclear Instruments and Methods in Physics Research B, 242(1-2), p.377 - 379, 2006/01

 Times Cited Count:8 Percentile:45.46(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Pressure-temperature-time-transition diagram in a strong metallic supercooled liquid

Wang, W. H.*; Utsumi, Wataru; Wang, X. L.*

Europhysics Letters, 71(4), p.611 - 617, 2005/08

 Times Cited Count:5 Percentile:60.87(Physics, Multidisciplinary)

The crystallization kinetics and nucleation mechanism of a bulk metallic glassforming alloy Zr$$_{46.75}$$Ti$$_{8.25}$$Cu$$_{7.5}$$Ni$$_{10}$$Be$$_{27.5}$$ (vit4) in the entire supercooled liquid region (SLR) is investigated using in situ high-pressure and high-temperature X-ray diffraction with synchrotron radiation, which allows us for the time to simultaneously determine the crystallization kinetics and phase evolution of a metallic liquid as a function of time under high pressure. The results are summarized in a pressure-time-temperature-transformation (PTTT) diagram with two time scales.

Journal Articles

Structure of Mg$$_{2}$$SiO$$_{4}$$ glass made by a method for containerless supercooled-liquid-phase processing at high temperatures

Kohara, Shinji*; Suzuya, Kentaro; Takeuchi, Ken*

Mirai Zairyo, 5(4), p.28 - 33, 2005/04

We succeeded in producing highly pure glass made of "forsterite," contained in upper mantle of the Earth and meteorites. Although ordinary glass is made of silica network structure, this glass has an unsymmetrical network structure of magnesium oxide polyhedrons, which is deemed to destroy the silica network structure. We produced glass with extremely rare impurities by melting forsterite while floating it with inert gas and sound waves and then quenching it while holding it in an approximate microgravity condition equivalent to space. Development of a new optical fiber and improvement and cost reduction of operating equipment, such as operation laser, because high-purity glass can be produced using materials, which has been deemed to be appropriate.

Journal Articles

The Disordered 3-dimensional structure visualized by a combination of high-energy synchrotron X-rays and computer simulations

Kohara, Shinji*; Oishi, Yasuo*; Takata, Masaki*; Yoneda, Yasuhiro; Suzuya, Kentaro

Nippon Kessho Gakkai-Shi, 47(2), p.123 - 129, 2005/04

The use of high-energy (E $$>$$ 50 keV) X-rays from SPring-8 allows us to perform X-ray diffraction experiments on disordered materials with the following advantages: high resolution in real space due to the wide range of scattering vector, small correction terms (particularly the absorption correction), and fast diffraction measurement with small amount of samples. Recently, high-energy X-ray diffraction data have been combined with neutron diffraction data from a pulsed neutron source to provide more detailed and reliable structural information than has hitherto been available. Furthermore, the use of reverse Monte Carlo modelling and PDF (pair distribution function) simulation based on high-energy X-ray diffraction data have succeeded in illustrating 3-dimensional structure of disordered materials and disorder in crystalline materials.

Journal Articles

Unusual structure in vitreous forsterite synthesized by an aero-acoustic levitation technique

Kohara, Shinji*; Suzuya, Kentaro; Takeuchi, Ken*

Nippon Maikurogurabiti Oyo Gakkai-Shi, 22(2), p.100 - 104, 2005/04

Forsterite Mg$$_{2}$$SiO$$_{4}$$ exhibits an orthorhombic structure consisted of two kinds of MgO$$_{6}$$ octahedra. Given only 33.3 mol% of SiO$$_{2}$$ in the material, the SiO$$_{4}$$ tetrahedra are isolated within the framework, sharing the O-O bonds with the common edges of the MgO$$_{6}$$ octahedra. If forsterite can be vitrified, an interesting question concerning the glass structure arises because there is insufficient glass forming SiO$$_{2}$$ to establish the corner-sharing SiO$$_{4}$$ tetrahedral network needed in conventional silicate glasses. A bulk Mg$$_{2}$$SiO$$_{4}$$ glass was synthesized using an aero-acoustic levitation technique and to determine the short- to intermediate-range structure by a combined high-energy X-ray and neutron diffraction and reverse Monte Carlo computer simulation. Interestingly, we found that the role of network former is largely taken on by corner- and edge-sharing ionic magnesium species that adopt 4-, 5- and 6-coordination with oxygen.

Journal Articles

X-ray structural analysis of molten PbCl$$_2$$

Okamoto, Yoshihiro; Iwadate, Yasuhiko*; Fukushima, Kazuko*; Matsuura, Haruaki*; Minato, Kazuo

Journal of Physics and Chemistry of Solids, 66(2-4), p.452 - 455, 2005/02

 Times Cited Count:6 Percentile:67.51(Chemistry, Multidisciplinary)

The structure of molten PbCl$$_2$$ was investigated by using X-ray diffrtaction(XRD) and X-ray absorption fine structure(XAFS) analysis techniques. From the fourier transformation analysis if the XRD data, the nearest Pb$$^{2+}$$-Cl$$^-$$ interaction consists of two kinds of interactions; rigid 4-fold tetrahedron and 2-3 loose coordination. The XAFS result shows a local structure is the 4-fold coordination in the melt.

Journal Articles

$$^{151}$$Eu-M$"o$ssbauer spectroscopic and X-ray diffraction study of the Eu$$_{2}$$(Ce$$_{1-x}$$Zr$$_{x}$$)$$_{2}$$O$$_{7}$$ and LnEuZr$$_{2}$$O$$_{7}$$(Ln=lanthanide) systems

Masaki, Nobuyuki; Nakamura, Akio; Furuuchi, Fumihito*; Hinatsu, Yukio*

Journal of Physics and Chemistry of Solids, 66(2-4), p.312 - 317, 2005/02

 Times Cited Count:8 Percentile:60.31(Chemistry, Multidisciplinary)

no abstracts in English

Journal Articles

Intermediate-range order in vitreous SiO$$_{2}$$ and GeO$$_{2}$$

Kohara, Shinji*; Suzuya, Kentaro

Journal of Physics; Condensed Matter, 17(5), p.S77 - S86, 2005/02

 Times Cited Count:65 Percentile:9.96(Physics, Condensed Matter)

The total structure factors, S(Q), obtained from high-energy X-ray and neutron diffraction measurements on vitreous SiO$$_{2}$$ (v-SiO$$_{2}$$) and vitreous GeO$$_{2}$$ (v-GeO$$_{2}$$) have been analysed by the reverse Monte Carlo (RMC) modelling technique to generate a three-dimensional structural model. The bond angle distributions and the ring size distributions from the model indicated that the sixfold ring and six- and sevenfold rings are dominant in v-SiO$$_{2}$$ and v-GeO$$_{2}$$, respectively. However, the fraction of threefold rings of Ge in v-GeO$$_{2}$$ is larger than that of Si in v-SiO$$_{2}$$ glass. These features are consistent with the published neutron diffraction and Raman scattering studies.

Journal Articles

Structural study of molten lanthanum halides by X-ray diffraction and computer simulation techniques

Okamoto, Yoshihiro; Madden, P. A.*

Journal of Physics and Chemistry of Solids, 66(1), p.448 - 451, 2005/01

The local structure of molten LaCl$$_3$$ has been characterized by the octahedral coordination (LaCl$$_6$$)$$^{3-}$$. It is based on X-ray diffraction (XRD) and Raman spectroscopy results. On the other hand, a different structural image was proposed in the neutron diffraction (ND) and the molecular dynamics (MD) studies. These ND and MD works concluded that a coordination behavior changes with cation size in molten rare earth trichlorides. Thus, they reported the coordination number of Cl$$^-$$ ions around La$$^{3+}$$ ion is 8.2 in the ND work and 7.9 in the MD work. In the present work, XRD measurements of molten LaCl$$_3$$ were performed to investigate the local structure. The coordination number of the 1st La$$^{3+}$$-Cl$$^-$$ pair in molten LaCl$$_3$$ was 7.1 from analysis of the correlation function G(r). The structural change by increasing anion size was examined by the XRD measurement of molten LaBr$$_3$$. The XRD data were nicely reproduced by the MD simulations with polarizable ionic model.

214 (Records 1-20 displayed on this page)