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排序方式: 共有515条查询结果,搜索用时 15 毫秒
1.
2.
Tomoya Suzuki Kento Shiota Yu-ichiro Izato Masahiro Komori Koichi Sato Yasuyuki Takai Takayuki Ninomiya Atsumi Miyake 《International Journal of Hydrogen Energy》2021,46(11):8329-8343
Although hydrogen refueling stations (HRSs) are becoming widespread across Japan and are essential for the operation of fuel cell vehicles, they present potential hazards. A large number of accidents such as explosions or fires have been reported, rendering it necessary to conduct a number of qualitative and quantitative risk assessments for HRSs. Current safety codes and technical standards related to Japanese HRSs have been established based on the results of a qualitative risk assessment and quantitative effectiveness validation of safety measures over ten years ago. In the last decade, there has been much development in the technologies of the components or facilities used in domestic HRSs and much operational experience as well as knowledge to use hydrogen in HRSs safely have been gained through years of commercial operation. The purpose of the present study is to conduct a quantitative risk assessment (QRA) of the latest HRS model representing Japanese HRSs with the most current information and to identify the most significant scenarios that pose the greatest risks to the physical surroundings in the HRS model. The results of the QRA show that the risk contours of 10?3 and 10?4 per year were confined within the HRS boundaries, whereas the risk contours of 10?5 and 10?6 per year are still present outside the HRS. Comparing the breakdown of the individual risks (IRs) at the risk ranking points, we conclude that the risk of jet fire demonstrates the highest contribution to the risks at all of the risk ranking points and outside the station. To reduce these risks and confine the risk contour of 10?6 per year within the HRS boundaries, it is necessary to consider risk mitigation measures for jet fires. 相似文献
3.
A simple and successful design method that yields a wideband and compact antenna without a ground plane is proposed. The antenna, referred to as the folded loop antenna, can, with the right parameters, achieve wideband characteristics. Calculated and measured results agree well and more than 50% bandwidth (return loss /spl les/-10 dB) is obtained. 相似文献
4.
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
5.
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
6.
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
7.
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
8.
Masahiro Kato Kazuaki Nakagawa Kenji Essaki Yukishige Maezawa Shin Takeda Ryosuke Kogo Yoshikazu Hagiwara 《International Journal of Applied Ceramic Technology》2005,2(6):467-475
We have discovered a series of lithium-containing oxides that immediately react with ambient carbon dioxide (CO2 ) up to 700°C. The products react and return reversibly to the oxides at a temperatures higher than about 700°C. The absorption capacity surpasses that of other CO2 absorbents by a factor of 10. Utilizing these absorbents, the possibility of a CO2 separation system that operates at around 500°C is proposed. It is generally believed that a CO2 separation process operable at temperatures higher than 500°C has the special benefit of a small energy penalty. Moreover, the absorption also proceeds at ambient temperature in the atmospheric environment. This property offers the possibility of many other applications, such as air cleaners or cartridges. Therefore, we think these materials have the potential to make a valuable contribution to the realization of CO2 emission control. 相似文献
9.
This paper describes a method of finding the proper points for dividing a corpus with time series information to extract local and frequent keywords. Previous works have proposed the corpus separating method for extracting keywords from a corpus. However, this method divides a corpus at equal intervals so that it cannot consider the topic changes. The present paper utilizes the idea of the topic model and the topic extracted through latent Dirichlet allocation to consider the topic change. This paper identifies the points at which large topic changes occur to divide the corpus using structural change detection method. An experiment involving newspaper articles with 5-year topics confirm that the points at which the topics of each document change are detected to find the division points based on the idea of structural change point detection and our method is better than previous methods based on recall measure. 相似文献
10.
Yoshiaki Katada Akihiro Nishiguchi Kazuya Moriwaki Ryosuke Watakabe 《Artificial Life and Robotics》2016,21(3):295-301
One approach in swarm robotics is homogeneous system which is embedded with sensing, computing, mobile and communication components. In this study, a target detection problem, which is one of navigation problems, was employed. Once a robot detects a target, robots immediately communicate with a base station via intermediate relay robots due to the multi-hop transmission of wireless communication. Therefore, this control task is completed with connectivity of the network. In a target detection problem, we must improve the performance of exploration as well as connectivity of the network. This study investigates the performances of the two types of random walk algorithm in navigation while loosely ensuring connectivity of the robotic network based on our previous study. 相似文献