T. Ohsaka

Tohoku University

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Lattice Dynamics of Solid CS₂Based on Kihara Potential

Journal of the Physical Society of Japan (1989)

Yukio Shibata K. Ishi T. Ohsaka

The lattice dynamics of molecular crystal CS 2 is studied within the rigid molecule and harmonic approximations, on the basis of Kihara core potential. Frequencies of lattice vibrations, dispersion curves, density of states and heat capacity at low temperatures are calculated. The results are in good agreement with experimental data and also compared with previous calculations. A role of nonaxisymmetric short-range interactions is discussed.

Lattice (music)

Lattice vibration

10.1143/jpsj.58.3198

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Citations (1)

Water Absorption and Thermal Behavior of Potassium Tetratitanate

Journal of the Ceramic Association Japan (1977)

Yoshinori Fujiki Fujio IZUMI T. Ohsaka Mamoru Watanabe

四チタン酸カリウム (K2Ti4O9) の吸湿と吸水性及び熱的挙動について, TG, DTA, IRスペクトル, 高温X線回折の方法により研究した. K2Ti4O9の合成結晶質粉末の大気中における吸湿は100時間で3.5wt%まで増量して一次飽和するが, 更に700時間で9wt%に達して飽和した. この吸着水分は層間水として1席を占有する. 本相の熔融点はDTAを用いて1114℃±10℃と決定した.室温で48時間蒸溜水中に浸漬したK2Ti4O9相は12.1wt%まで水分を吸着した. この水分は層間水と結合水の2席を占有する. 本相は750℃以上に加熱するとK2Ti6O13相へ移行した. この相変化は加水分解によりK+イオンが溶脱されたためである.室温で40時間1規定酢酸溶液中に浸漬したK2Ti4O9相は16.4wt%まで水分を吸着した. この水分は層間水と2種類の結合水に相当する3席を占有する. 本相は700℃以上の温度で若干のK2Ti4O9相を伴うが大部分はアナターゼ型TiO2に移行する.K2Ti4O9相のIRスペクトルを250-700cm-1の範囲内でKBr錠剤法で測定した. 510cm-1, 460cm-1, 420cm-1 (肩), 300cm-1の波数において特徴的な吸収帯を示し, これらは吸湿と吸水性の相違に基づいて変化した. また, K2Ti4O9相のCa2+イオンに対する陽イオン交換反応を試みた結果, 交換容量として0.25meq/gを示した.

10.2109/jcersj1950.85.986_475

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Citations (13)

Infrared spectra of glassy Se containing small amounts of S, Te, As, or Ge

Journal of Non-Crystalline Solids (1975)

T. Ohsaka

Absorption band

10.1016/0022-3093(75)90119-2

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Citations (35)

Temperature Change of the Far-Infrared Absorption and Nature of Low-Frequency Modes in Silica Glass

Journal of the Physical Society of Japan (2000)

T. Ohsaka Tadanobu Shoji Kazuya Tanaka

The far-infrared absorption of three kinds of silica glasses with different OH concentrations has been measured at 11 K in the region 10–100 cm -1 and compared with the absorption at 297 K. Below the so-called boson peak, the absorption was markedly dependent on temperature, but by contrast above the boson peak, it was almost independent of temperature, indicating the existence of two different types of low-frequency modes. It is suggested that the temperature-dependent absorption is due to structural relaxation modes, and the temperature-independent absorption reflects the density of states of collective motions of atoms related to clusters, though it is incomprehensible why the absorption is temperature independent.

Silica glass

10.1143/jpsj.69.3711

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Effect of hydrostatic pressure on the Raman spectrum of anatase (TiO2)

Solid State Communications (1979)

T. Ohsaka S. Yamaoka Osamu Shimomura

Hydrostatic pressure

10.1016/0038-1098(79)90648-3

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Citations (160)

Infrared diffuse reflectivity study of high-Tcsuperconductors

Physical review. B, Condensed matter (1990)

A. Rosenberg A. S. Barker T. W. Noh T. Ohsaka A. J. Sievers

We have measured the spectral dependence of the diffuse reflectivity of polished sintered pellets of ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathit{y}}$, ${\mathrm{La}}_{2\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Sr}}_{\mathit{x}}$${\mathrm{CuO}}_{4\mathrm{\ensuremath{-}}\mathit{y}}$, and related superconducting and nonsuperconducting oxides between 500 and 5000 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ at room temperature. The growth in ir scattering with decreasing frequency is qualitatively explained by the anisotropic conductivity of these materials. Even at its peak ir value the effect is too small to alter significantly the optical constants obtained from specular reflectivity measurements. Since no additional scattering occurs near 0.5 eV, the absorption observed in sintered pellets at that energy cannot be associated with an anisotropic electronic excitation.

10.1103/physrevb.41.7213

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Backward Transition Radiation from a Concave Mirror(III. Accelerator and Synchrotron Radiation)

行男柴田理志佐々木君弘伊師勉蔦谷俊明大坂

Transition radiation

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Raman scattering studies of the one-dimensional ionic conductors K-B-priderites (B=Zn, Ga) and potassium gallotitanogallate

Solid State Ionics (1990)

M. Ishii Y. Fujiki T. Ohsaka

10.1016/0167-2738(90)90309-f

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13a-DC-11 Spectroscopy by Coherent Transition in the Far Infrared and Millimeter Wavelength Region

Abstracts of the meeting of the Physical Society of Japan. Sectional meeting (1993)

Toshiyuki Ihara T. Ohsaka Takehiro Takahashi S. Hasebe F. Arai

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Spectrum of coherent synchrotron radiation

T. Nakazato M. Oyamada Nobuo Niimura S. Urasawa Y. Shibasaki

A spectrum of coherent synchrotron radiation was measured at wavelengths of from 0.16 to 3.5 mm. The experiment was carried out using the Tohoku 300-MeV linac, whose accelerating frequency was 2856 MHz. A bunch shape was estimated by Fourier analysis for this spectrum. This result agrees with that of simulation for the bunching process in the injector of the accelerator. The interference effects between radiation emitted by the successive bunches were observed by an interferometer. It was shown that every radiation had the same phase when it was emitted by a bunch.< >

Bunches

10.1109/pac.1991.164552

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Citations (2)