首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   7篇
  免费   5篇
  国内免费   3篇
化学   6篇
物理学   9篇
  2022年   1篇
  2019年   2篇
  2014年   1篇
  2013年   1篇
  2012年   4篇
  2011年   1篇
  2002年   3篇
  2001年   1篇
  1999年   1篇
排序方式: 共有15条查询结果,搜索用时 0 毫秒
1.
High-temperature thermoelectric transport property measurements have been performed on the highly c-axis oriented Bi2Sr2Co20v thin films prepared by pulsed laser deposition on LaA1Oa (001). Both the electric resistivity p and the seebeck coefficient S of the film exhibit an increasing trend with the temperature from 300 K-1000 K and reach up to 4.8 m. cm and 202 V/K at 980 K, resulting in a power factor of 0.85 mW/mK which are comparable to those of the single crystalline samples. A small polaron hopping conduction can be responsible for the conduction mechanism of the film at high temperature. The results demonstrate that the Bi2Sr2Co2Oy thin film has potential application has high temperature thin film thermoelectric devices,  相似文献   
2.
High-temperature thermoelectric transport property measurements have been performed on the highly c-axis oriented Bi2Sr2Co2Oy thin films prepared by pulsed laser deposition on LaAlO3(001).Both the electric resistivity ρ and the seebeck coefficient S of the film exhibit an increasing trend with the temperature from 300 K-1000 K and reach up to 4.8 m·Ω· cm and 202 μV/K at 980 K,resulting in a power factor of 0.85 mW/mK which are comparable to those of the single crystalline samples.A small polaron hopping conduction can be responsible for the conduction mechanism of the film at high temperature.The results demonstrate that the Bi2Sr2Co2Oy thin film has potential application in high temperature thin film thermoelectric devices.  相似文献   
3.
燃料电池用质子交换膜的研究进展   总被引:12,自引:0,他引:12  
质子交换膜燃料电池(PEMFC)以质子交换膜(PEM)作为电解质和隔膜,其性能强烈地依靠PEM的性质。本文分析了PEMFC对PEM的要求,对全氟化、部分氟化和非氟化的PEM进行了分类介绍,着重讨论了膜的结构、制备、性质以及它们在PEMFC中的应用。  相似文献   
4.
基于灰度空间极值法的块煤边缘检测   总被引:1,自引:1,他引:0  
在用图象处理的方法监测原煤块率时,检测出每块煤的边缘是很重要的.本文在块煤图象的边缘检测过程中,对几种经典边缘检测算子进行了实验验证,最后得出结论认为,采用灰度空间极值法效果最佳.  相似文献   
5.
针对新一代高油气比(0.051及以上)航空发动机燃烧室,本文提出头部采用化学恰当比直接混合燃烧设计方案。对于新一代高压比(70及以上)低排放民用航空发动机燃烧室,由于其自着火延迟时间极短,因此采用贫油直接混合燃烧,而不能采用预混合预蒸发燃烧。本文提出了一种贫油直接混合低排放燃烧室方案,其燃油空气模由简单的压力雾化喷嘴和轴向旋流器组成,结合燃油分级技术降低污染物排放,该燃烧室具有较好的燃烧稳定性。这两类燃烧室的燃烧空气分数非常大,因此存在慢车贫油熄火问题。文中针对两类燃烧室分别提出了相应的解决方案,同时介绍了火焰筒外壁面及内壁面的冷却设计方案。本文研究成果可为下一代航空发动机燃烧室的发展提供指导作用。  相似文献   
6.
质子交换膜燃料电池Nafion/PTFE复合膜的研究   总被引:1,自引:1,他引:0  
在聚四氯乙烯(PTFE)多孔膜内浸入Nasfion树脂,制成Nasfion/PTFE复合膜用于质子交换膜燃料电池(PEMFC),该复合膜的Nasfion含量在50%左右,在干态和湿态时的拉伸强度及水化/脱水过程中,其尺寸稳定性比Nasfion均有所提高,在80℃,H2/O2压力为0.2/0.2MPa条件下,用25μm厚复合膜组装的电池性能优于Nasfion117膜组装电池的性能,测量了复合膜的O2渗透率和含水量并与Nasfion膜的性能作了比较。  相似文献   
7.
8.
A Bi2Sr2Co2Oy/Si heterojunction is obtained by growing a layer of p-type oxygen-deficient Bi2Sr2Co2Oy film on a commercial n-type silicon wafer by pulsed laser deposition. Its rectifying and photovoltaic properties are studied in a wide temperature range from 20 K to 300 K. The transport mechanism under the forward bias can be attributed to a trap- filled space-charge-limited current conduction mechanism. Under the irradiation of a 532-nm continuous wave laser, a clear photovoltaic effect is observed and the magnitude ofphotovoltage increases as the temperature decreases, The results demonstrate the potential application of a Bi2SrzCo2Oy-based heterojunction in the photoelectronic devices.  相似文献   
9.
李志鹏  刘富强  孙剑 《中国物理 B》2011,20(8):88901-088901
In this paper,the lattice model is presented,incorporating not only site information about preceding cars but also relative currents in front.We derive the stability condition of the extended model by considering a small perturbation around the homogeneous flow solution and find that the improvement in the stability of traffic flow is obtained by taking into account preceding mixture traffic information.Direct simulations also confirm that the traffic jam can be suppressed efficiently by considering the relative currents ahead,just like incorporating site information in front.Moreover,from the nonlinear analysis of the extended models,the preceding mixture traffic information dependence of the propagating kink solutions for traffic jams is obtained by deriving the modified KdV equation near the critical point using the reductive perturbation method.  相似文献   
10.
燃油分级多点喷射低污染燃烧室的化学反应网络模型分析   总被引:4,自引:0,他引:4  
本文采用基于详细化学反应机理的化学反应网络模型分析了航空发动机燃油径向分级多点喷射低污染燃烧室的NO_x排放特性。该分级燃烧室不同于传统燃烧室,头部由值班区和主燃区两个不同的燃烧区域,根据CFD得到的流场特性和当量比的分布特性对燃烧室进行分区构建化学反应器网络模型,研究了值班级当量比以及值班级和主燃级两级供油比例对排放的影响。同时,还分析了空气进口温度对NO_x排放的影响。得到了较为合理的变化趋势,为低污染燃烧室的初步设计提供了有益的指导。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号