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排序方式: 共有664条查询结果,搜索用时 15 毫秒
1.
2.
Takashi Yamazaki Yoichi Takino Ryosuke Matsuoka Susumu Ito 《Electrical Engineering in Japan》1993,113(8):26-36
According to the recent analysis results of temporary ac overvoltage in the ac system connected with a frequency converter station, large-magnitude over-voltages were confirmed to occur under some special system conditions. Most of the station insulators currently used cannot withstand such overvoltages according to an evaluation based on the data obtained earlier. The necessity of tests to be done to evaluate such performance more accurately was recognized. Both power frequency and switching impulse overvoltage flashover tests were made on contaminated insulators by the method well simulating the natural wetting condition. Switching impulse flashover voltage with the waveshape having a long wavefront time of 2 ms can be well correlated with the flashover voltage characteristics of temporary ac overvoltage. Higher flashover voltage characteristics were obtained by a clean fog test method compared with those obtained by equivalent fog test method. 相似文献
3.
Titanium oxides were reduced to metallic titanium using the liquid calcium floating on the molten CaCl2. A part of Ca dissolved into CaCl2 and reacted with TiO2 settled below CaCl2. The by-product CaO also dissolved by about 20 mol pct into CaCl2, which was effective in reducing the oxygen concentration in the obtained Ti particles. The compositional region in the Ca-CaCl2-CaO system was examined for the less oxygen contamination in Ti and the better handling in leaching. A large amount of the
residual calcium oxidized the titanium powder in leaching. The metallic Ti powder less than 1000 mass ppm oxygen could be
obtained only for 3.6 ks using 5 to 7 mol pct Ca-CaCl2 at 1173 K. The powder was slightly sintered like sponge, and contained approximately 1500 ppm Ca. The anatase phae, the intermediate
product in the refining process of TiO2, could be also supplied as raw material as well as rutile. 相似文献
4.
M. Hara Y. Hatano T. Abe K. Watanabe T. Naitoh S. Ikeno Y. Honda 《Journal of Nuclear Materials》2003,320(3):265-271
To improve the durability of hydrogen storage materials against surface poisoning by impurity gases, effectiveness of Pd-coating layer prepared by using a Barrel-Sputtering System was examined for ZrNi powder. The effectiveness of Pd-coating was evaluated by activation temperature, at which Pd/ZrNi poisoned by air could be activated to absorb hydrogen. Characterization of Pd-coated ZrNi (denoted as Pd/ZrNi) by scanning electron microscopy, electron probe microanalysis and X-ray diffraction showed that a uniform Pd-coating layer was formed with the barrel-sputtering system. It was found that the poisoned Pd/ZrNi sample could be activated even at 423 K to absorb hydrogen at room temperature. This exhibits remarkable contrast to bare ZrNi, which could be only activated appreciably above 1073 K. It is concluded that the Pd-coating by barrel sputtering is quite effective to avoid the effect of surface poisoning of powdery hydrogen storage materials. However, the activation at excessively high temperature resulted in the loss of high activity to absorb hydrogen. It was concluded that this phenomenon was associated with reactions between Pd and ZrNi to form PdZr and other byproducts. 相似文献
5.
Bromelain inhibitor VI from pineapple stem (BI-VI) is a unique double-chain inhibitor with an 11-residue light chain and a 41-residue heavy chain by disulfide bonds and inhibits the cysteine proteinase bromelain competitively. The structure of BI-VI in aqueous solution was determined using nuclear magnetic resonance spectroscopy and simulated annealing-based calculations. Its three-dimensional structure was shown to be composed of two distinct domains, each of which is formed by a three-stranded antiparallel beta-sheet. Unexpectedly, BI-VI was found to share a similar folding and disulfide bond connectivities not with cystatin superfamily inhibitors which inhibit the same cysteine proteinases but with the Bowman-Birk trypsin/chymotrypsin inhibitor from soybean (BBI-I). BBI-I is a 71-residue inhibitor which has two independent inhibitory sites toward the serine proteinases trypsin and chymotrypsin. These structural similarities with BBI-I suggest that they have evolved from a common ancestor and differentiated in function during a course of molecular evolution. 相似文献
6.
T. Hatano M. Kaise K. Saito K. Nakamura C. S. Kim Y. K. Cho 《Journal of Low Temperature Physics》1996,105(5-6):1295-1300
Artificially layered Bi2Sr2Can–1CunO4+n films were synthesized by sequential sputter deposition of BiO, SrCu0.5O1.5 and CaCuO2 layers. Annealing behavior of these films which were irradiated by Ar ions was studied. Defect assisted improvement of their crystalline perfection is expected which might results in the improvement of the superconducting properties of these films. An artificial film, such as an intergrowth of 2223 and 2234 phases, and superstructure films of (2245)1(2201)1 and (2234)1(2212)1, were irradiated by Ar ions (150 keV, 2–10×1012 ions/cm2) and annealed at 730 °C. An improvement of superconducting transition temperatures were observed. 相似文献
7.
Hatano H. Kanai S. 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1996,43(4):531-535
Transmission characteristics of a double-structured tank, used for high-frequency (1 MHz range) ultrasonic cleaning of semiconductor wafers and substrates, were improved by utilizing oblique incidence of ultrasonic waves. As the sound transmittivity through a plate in water varies with the angle of incidence, the bottom of the Pyrex glass inner container was slanted at the angle where strong transmission occurred. In the slant-bottom container, an intensive and uniform sound pressure distribution was measured with a polyvinylidene fluoride (PVDF) hydrophone probe. In comparison with the conventional horizontal-bottom container, it was shown that the distributions as well as amplitude of sound pressure were remarkably improved by slanting the bottom of the inner container at the proper angle 相似文献
8.
Yuma Sano Ryosuke Nonaka Masahiro Baba 《Journal of the Society for Information Display》2012,20(9):539-546
This paper proposes a wide gamut LCD using locally dimmable four‐primary‐color (4PC) LED backlight. Although the color gamut of LCDs has been improved in recent years, it is insufficient to reproduce all the colors in the real world. The objective of this paper is to propose a wide gamut LCD that reproduces all the colors in the real world while keeping the cost increases to a minimum. We evaluated the color gamut reproduced by LEDs of multiple primary colors and selected cyan as the optimal color to be added to the three primary colors to reproduce all the colors in the real world. Therefore, we designed an LED backlight consisting of an additional only‐cyan LED with three‐primary‐color LEDs and developed a prototype LCD with 4PC LED backlight. Furthermore, we developed a local dimming algorithm for the 4PC LED backlight. As a result, we confirmed that the prototype LCD with the 4PC LED backlight is able to cover almost all the colors in the real world and also able to display natural images with highly saturated colors by local dimming. 相似文献
9.
Hiroyuki Sugiyama Takuto Sekiguchi Ryosuke Matsumura Shunpei Yamashita Yoshihiro Suda 《Multibody System Dynamics》2012,27(1):55-74
In railroad turnouts, geometries of tongue and crossing rails are very complex and their shapes are changing along the track.
Therefore, wheels are subjected to not only tread and flange contacts, but also the back-of-flange and top-of-flange contacts
in the case of spring switches of tram vehicles. For this reason, one needs to deal with significant jumps in contact points
for solving wheel/rail contact problems in turnout, and an accurate prediction of jumps in contact points is one of the most
important issues that need to be carefully handled in the dynamic simulation of vehicle/turnout interactions. In this investigation,
a numerical procedure that can be used for solving such a complex wheel/rail contact problem in turnout is proposed. In particular,
a combined nodal and non-conformal contact approach is developed such that significant jumps in contact points are detected
using the nodal search, while the exact location of contact point is then determined with continuous surface parameterizations
using non-conformal contact equations. With this combined nodal and non-conformal contact approach for the contact geometry
analysis of vehicle/turnout interactions, multiple look-up contact tables can be generated in an efficient way without losing
accuracy. Since detailed contact search is performed off-line to obtain look-up contact tables, significant changes in contact
points in turnout can be efficiently predicted on-line with tabular data to be interpolated in a standard way. Several numerical
examples are presented in order to demonstrate the use of the numerical procedure developed in this investigation. 相似文献
10.