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排序方式: 共有203条查询结果,搜索用时 15 毫秒
61.
We propose a plasma chemical vaporization machining device with a hemispherical tip electrode for optical fabrication. Radio-frequency plasma is generated close to the electrode under atmospheric conditions, and a workpiece is scanned relative to the stationary electrode under three-axis motion control to remove target areas on a workpiece surface. Experimental results demonstrate that surface removal progresses although process gas is not forcibly supplied to the plasma. The correction of shape errors on conventionally polished spheres is performed. As a result, highly accurate smooth surfaces with the desired rms shape accuracy of 3 nm are successfully obtained, which confirms that the device is effective for the fabrication of optics. 相似文献
62.
Akihisa Kubota Hidekazu Mimura Kouji Inagaki Kenta Arima Yuzo Mori Kazuto Yamauchi 《Journal of Electronic Materials》2005,34(4):439-443
In this work, elastic emission machining (EEM), which is a precise surface-preparation technique using chemical reactions
between the surfaces of work and fine powder particles, is applied to the flattening 4H-SiC (0001) surface. Prepared surfaces
are observed and characterized by optical interferometry, atomic force microscopy (AFM), and low-energy electron diffraction
(LEED). The obtained images show that the processed surface has atomic-level flatness, and the subsurface damage and surface
scratches of the preprocessed surface are almost entirely removed. 相似文献
63.
Hiroyuki Fujishiro Manabu Ikebe Yuzo Shibazaki 《Journal of Low Temperature Physics》1999,117(5-6):1181-1185
The thermal conductivity has been measured for La
2-X
Sr
X
CuO
4
and La
1.85
Sr
0.15
Cu
0.98
M
0.02
O
4
(M; Zn, Ni). The characteristic enhancement in below T
c
was confirmed for La
1.85
Sr
0.15
CuO
4
. The phonon scattering mechanisms were analyzed in detail and the electron-phonon coupling constant was estimated to be 0.05. The enhancement becomes indetectable on Zn or Ni substitution for Cu, which indicated survival of the phonon scattering by charge carriers down to lower temperatures as a result of reduced T
c
. 相似文献
64.
Kazuhiko Masuda Yuzo ManoHiroshi Ishimoto Masami TokunoYoshito Yoshizaki Nozomu OkawaraRyutaro Yamagiwa Akihiro UchiyamaAkihiro Yamazaki Yukitomo Tsutsumi 《Remote sensing of environment》2003,85(4):484-488
Optical thickness of the Asian dust aerosols over the ocean near Japan was retrieved from the visible data of the Geostationary Meteorological Satellite (GMS-5) from April 7 to 22, 2002 using the method by Masuda et al. [Remote Sens. Environ. 82 (2002) 238] in which the nonsphericity of dust particles was taken into account. The retrieved optical thicknesses were then compared with those derived from the sunphotometer and the skyradiometer measurements. The mean and the standard deviation of the optical thickness difference, GMS minus radiometers, were −0.03 and 0.17, respectively, for 85 samples where the optical thickness ranges from 0.25 to 1.07. 相似文献
65.
Yasuharu Imai Sumio Kawata Masami Inada Shio Miyoshi Yuzo Minami Yuji Matsuzawa Kiyohisa Uchida Seiichiro Tarui 《Lipids》1987,22(7):513-516
Effects of cholestyramine on biliary secretion of cholesterol, phospholipids and bile acids and fecal excretion of sterols
and bile acids were examined in Wistar male rats. Six rats were fed a basal diet, and the other six were fed a basal diet
supplemented with 5% cholestyramine for eight days. Bile flow and biliary secretion of bile acids and phospholipids (per hour
per rat) decreased with cholestyramine treatment, while biliary cholesterol secretion (per hour per rat) remained unchanged.
In the biliary bile acid composition, a marked increase of chenodeoxycholic acid with a concomitant decrease of β-muricholic
acid was observed in cholestyramine-treated rats. Fecal excretion of total sterols and bile acids increased about three-and
four-fold, respectively, after cholestyramine treatment. The increase of fecal bile acids derived from cholic acid was more
predominant than that derived from chenodeoxylcholic acid, resulting in an increase of the cholic acid group/chenodeoxycholic
acid group ratio. 相似文献
66.
The high temperature electron spin resonance technique has been used to obtain in situ information on the behaviour of liquefaction catalysts during coal pyrolysis. The spin concentration in coal was induced in the presence of a catalyst at the pyrolysis temperature. ZnCl2 drastically increased the spin concentration of coal. The order of activity of the catalysts with respect to the increase in spin concentration was: ZnCl2 (impregnated) ?ZnCl2 (dispersed) >ZnCl2/KCl>SnCl2 > SbCl3≈AlCl3 ≈CaCl2 > coal alone. 相似文献
67.
Reduction of AC flashover strength by the attachment of insulating strings on the insulator surfaces
Yoshiaki Yamano Emi Ishikawa Yuzo Takahashi Shigeo Kobayashi 《Electrical Engineering in Japan》1992,112(2):22-30
AC flashover voltage in air (ACFOV) decreases when nylon string is attached on the PMMA insulator surface which has a backside electrode. The decrease in ACFOV by the attachment is explained by the generation and the propagation of the negative surface leader along the string. When the contact angle between the HV electrode and the insulator surface is in a range from 90° to 120°, some of the negative surface leaders generated proceed along the string to the grounded counterelectrode. The magnitude of the negative leader along the string is stronger than that of the leader on the insulator without a string. In the range of the contact angle from 120° to 180°, the negative surface leader which does not appear on the insulator without a string is generated along the string by the attachment. In both ranges of the contact angle, the negative leader along the string promotes the flashover. 相似文献
68.
We introduce a neural network of self-organizing feature map (SOM) to classify remote-sensing data, including microwave and
optical sensors, for the estimation of areas of planted rice. This method is an unsupervised neural network which has the
capability of nonlinear discrimination, and the classification function is determined by learning. The satellite data are
observed before and after rice planting in 1999. Three sets of RADARSAT and one set of SPOT/HRV data were used in Higashi–Hiroshima,
Japan. The RADARSAT image has only one band of data and it is difficult to extract the rice-planted area. However, the SAR
back-scattering intensity in a rice-planted area decreases from April to May and increases from May to June. Therefore, three
RADARSAT images from April to June were used in this study. The SOM classification was applied the RADARSAT and SPOT data
to evaluate the rice-planted area estimation. It is shown that the SOM is useful for the classification of satellite data. 相似文献
69.
Bidirectional optical coupler for plastic optical fibers 总被引:1,自引:0,他引:1
We have developed a low-loss bidirectional optical coupler for high-speed optical communication with plastic optical fibers (POFs). The coupler, which is fabricated by an injection molding method that uses poly (methyl methacrylate), has an antisymmetric tapered shape. We show that the coupler has low insertion and branching losses. The tapered shape of the receiving branch reduces beam diameter and increases detection efficiency coupling to a photodetector, whose area is smaller than that of the plastic optical fiber. The possibility of more than 15-m bidirectional transmission with a signaling bit rate up to 500 Mbits/s for simplex step-index POFs is demonstrated. 相似文献
70.