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71.
H. Watanabe K. Hirota O. Yamaguchi S. Inamura H. Miyamoto N. Shiokawa K. Tsuji 《Journal of Materials Science》1994,29(14):3719-3723
In compositions having ZrO2/Y2O3=(74.25–71.25)/(0.75–3.75) (mol% ratio) with 25 mol% Al2O3, metastable t-ZrO2 solid solutions crystallize at 780° to 860°C from amorphous materials prepared by the simultaneous hydrolysis of zirconium, yttrium and aluminium acetylacetonates. Hot isostatic pressing has been performed for 1 h at 1130 and 1230°C under 196 MPa using their powders. Two kinds of material are fabricated: (i) perfect ZrO2 solid-solution ceramics and (ii) composites of ZrO2 solid solution and -Al2O3. Their mechanical properties are examined, in connection with microstructures and t/m ZrO2 ratios. Composites with a homogeneous dispersed -Al2O3 derived from solid-solution ceramics result in a remarkable increase of strength. 相似文献
72.
Composite bodies in the system Al–Zr–C, with about 95% relative density, were obtained by heating the compact body of powder mixture consisting of Al and ZrC (5 : 1 mol %) in Ar at 1100–1500°C for various lengths of time. Components of the material heated at more than 1200°C were Al, Al3Zr, ZrC and AlZrC2. The Al3Zr exhibited plate-like aggregation, and its size increased with increasing temperature. In the material heated at 1500°C for 1 h, the largest plate-like Al3Zr aggregation was 2000 m long and 133 m thick. Then the AlZrC2 was present as well-proportioned hexagonal platelet particles with a 8–9 m diameter and a 1–2 m thickness in the interior of the plate-like Al3Zr aggregation and Al matrix phase. The average three-point bending strength of the bodies was 140–190 MPa, and the maximum strength was 203 MPa in the body heated at 1300°C for 1 h. The body heated at 1500°C for 1 h showed high oxidation resistivity to air up to 1000°C. 相似文献
73.
Takayuki Ito Hiroyuki Yamaguchi Katsuya Okabe Taizo Masumi 《Journal of Materials Science》1998,33(14):3555-3566
We have prepared a large number of crystals of cuprous oxide (Cu2O) by various procedures. Photoluminescence spectra of these crystals were studied to examine the concentration of defects, especially copper vacancy VCu to seek favourable conditions for growing Cu2O crystal. High-quality single crystals of Cu2O were prepared by the floating-zone melting method in air. Several synthetic crystals (specimens FA, FZ and GZ) and also a natural crystal were studied by X-ray analysis, inductively coupled plasma spectroscopy analysis, optical absorption, photoluminescence, photoconductivity and cyclotron resonance absorption, photoluminescence, photoconductivity and cyclotron resonance absorption to characterize their optical and electrical qualities. The best values of mobility and scattering time of photocarriers at T = 4.2 K are estimated to be h1.8 × 105 cm2 V–1 s–1 and h60 ps for positive holes, and 1.3 × 105 cm2 V–1 s–1 and 70 ps for electrons in Cu2O. Further, we report preliminary experimental results on transport property of crystals also of cupric oxide (CuO) purified by the floating-zone melting method. 相似文献
74.
Hiroki Yamaguchi Tsuneo Hanawa Oto Yamamoto Yu Matsuda Yasuhiro Egami Tomohide Niimi 《Microfluidics and nanofluidics》2011,11(1):57-64
The tangential momentum accommodation coefficient (TMAC) was investigated experimentally from the mass flow rate through a
single microtube under the slip flow and the early part of the transition regime. The measurements were carried out by the
constant-volume method under the mean Knudsen number smaller than 0.3, which is based on the mean pressure of the inlet and
the outlet of the microtube, to apply the second-order slip boundary condition. To measure TMACs on various materials, quite
large microtube was employed, which require the reduction in leakage. TMAC was obtained from the slip coefficient determined
by the relation of the mass flow rate to the mean Knudsen number. The obtained mass flow rate was well explained by the theoretical
equation. TMACs of deactivated-fused silica with argon, nitrogen, and oxygen were measured, showing the tangential momentum
was not accommodated completely to the surface, and the values showed good agreement with previous studies. From the comparison
between microtubes with different inner diameter, it is showed that TMAC is determined mainly by gas species and surface material. 相似文献
75.
Yuichiro Ezoe Ikuyuki Mitsuishi Utako Takagi Masaki Koshiishi Kazuhisa Mitsuda Noriko Y. Yamasaki Takaya Ohashi Fumiki Kato Susumu Sugiyama Raul E. Riveros Hitomi Yamaguchi Shinya Fujihira Yoshiaki Kanamori Kohei Morishita Kazuo Nakajima Ryutaro Maeda 《Microsystem Technologies》2010,16(8-9):1633-1641
We are developing novel ultra light-weight and high-resolution X-ray micro pore optics for space X-ray telescopes. In our method, curvilinear micro pore structures are firstly fabricated by silicon deep reactive ion etching (DRIE) or X-ray LIGA processes. Secondly, side walls of the micro structures are smoothed by magnetic field assisted finishing and/or hydrogen annealing techniques for high reflectivity mirrors. Thirdly, to focus parallel X-ray lights from astronomical objects, these structures are elastically or plastically bent into a spherical shape. Fourthly, the bent structures are stacked to form a multi-stage X-ray telescope. In this paper, we report on fabrication and X-ray reflection tests of silicon and nickel X-ray mirrors using the DRIE and LIGA processes, respectively. For the first time, X-ray reflections were confirmed on both of the mirrors. Estimated rms roughnesses were 5 nm and 3 nm for the silicon and nickel mirrors, respectively. 相似文献
76.
Database of human motion has been widely used for recognizing human motion and synthesizing humanoid motions. In this paper,
we propose a data structure for storing and extracting human motion data and demonstrate that the database can be applied
to the recognition and motion synthesis problems in robotics. We develop an efficient method for building a human motion database
from a collection of continuous, multi-dimensional motion clips. The database consists of a binary tree representing the hierarchical
clustering of the states observed in the motion clips, as well as node transition graphs representing the possible transitions
among the nodes in the binary tree. Using databases constructed from real human motion data, we demonstrate that the proposed
data structure can be used for human motion recognition, state estimation and prediction, and robot motion planning. 相似文献
77.
Tojo H Ejiri A Hiratsuka J Yamaguchi T Takase Y Itami K Hatae T 《The Review of scientific instruments》2012,83(2):023507
This paper presents an experimental demonstration to determine electron temperature (T(e)) with unknown spectral sensitivity (transmissivity) in a Thomson scattering system. In this method, a double-pass scattering configuration is used and the scattered lights from each pass (with different scattering angles) are measured separately. T(e) can be determined from the ratio of the signal intensities without knowing a real chromatic dependence in the sensitivity. Note that the wavelength range for each spectral channel must be known. This method was applied to the TST-2 Thomson scattering system. As a result, T(e) measured from the ratio (T(e,r)) and T(e) measured from a standard method (T(e,s)) showed a good agreement with <∣T(e,r) - T(e,s)∣∕T(e,s)> = 7.3%. 相似文献
78.
Koji Ishida Ken Hirota Osamu Yamaguchi Hideki Kume Suguru Inamura Hiroki Miyamoto 《Journal of the American Ceramic Society》1994,77(5):1391-1395
In the system ZrO2 –Al2 O3 , a new method for preparing ZrO2 solid solutions from ZrCl4 and AlCl3 using hydrazine monohydrate is investigated. c -ZrO2 solid solutions containing up to ∼40 mol% Al2 O3 crystallize at low temperatures from amorphous materials. The formation mechanism is discussed from IR spectral data. The values of the lattice parameter α increase linearly from 0.5072 to 0.5105 nm with increasing Al2 O3 content. At higher temperatures, transformation of the solid solutions proceeds as follows: c ( SS ) → t ( ss ) → t ( ss ) +α-Al2 O3 → m +α-Al2 O3 . m -ZrO2 –α-Al2 O3 composite ceramics are fabricated by hot isostatic pressing for 2 h at 1250°C and 196 MPa. Microstructures and mechanical properties are examined, in connection with increasing Al2 O3 content. 相似文献
79.
M Miyata T Yamamoyo M Yamaguchi K Nakao T Yoshida 《Canadian Metallurgical Quarterly》1976,152(4):540-543
Serial measurements of plasma "true glucagon" (PG) and of glucagon-like immunoreactive materials (GLI) were carried out during and after total resection of the pancreas in a 62-year-old man with calcified pancreatitis. The postoperative course of this patient was uneventful and diabetes was well controlled. PG disappeared from the blood within 30 min after resection of the pancreas. In spite of the evidence that no pancreatic tissue was present in the abdomen, PG was detected again in the blood from 18 hr after total pancreatectomy until the ninth postoperative day. However, plasma PG did not rise following infusion of arginine during the fourteenth postoperative week. After an initial decrease, plasma GLI rose abruptly on the second postoperative day and remained elevated thereafter. The fluctuations of plasma PG and GLI were not parallel. 相似文献
80.
Yasuyuki Kaneno Tetsuo Yamaguchi Takayuki Takasugi 《Journal of Materials Science》2006,41(20):6871-6880
The texture evolution during the hot-rolling and the recrystallization of B2-type Fe–48Al, Ni–50Al and Co–50Ti (expressed
by at.%) intermetallic compounds were investigated. By hot-rolling at 973 K, Fe–48Al showed a microstructure with coarse grains
elongated along rolling direction, while Ni–50Al and Co–50Ti showed a deformed microstructure featured by the heavily distorted
(elongated) grains and/or the deformation bands. The hot-rolling texture of Fe–48Al was composed of {111}<uvw>, while those
of Ni–50Al and Co–50Ti were composed of {111}<110> and {111}<112>, respectively. After annealing, the recrystallized grains
were preferentially nucleated at the grain boundaries for Fe–48Al, and in the heavily distorted regions or the deformation
bands for Ni–50Al and Co–50Ti. The orientations of the recrystallized grains were similar with those of the deformed matrix,
especially for Ni–50Al and Co–50Ti. The recrystallization textures were generally more dispersive than the hot-rolling texture.
Based on these results, the texture evolution during the hot rolling and the recrystallization of the B2-type intermetallic
compounds were discussed. 相似文献