共查询到20条相似文献，搜索用时 93 毫秒
1.
研究了受热阻、热漏和回热损失影响的不可逆斯特林制冷机制冷率和制冷系数的最高和最低界限。为斯特林制冷机工作参数的选择提供了两条有限时间热力学新准则。 相似文献
2.
本文介绍了依据斯特林热机的结构设计和建模一款利用斯特林热机的结构以热源和散热器远端作为温差条件驱动风扇转动加强气体流通和散热的半主动散热器。运用计算机建模技术,对斯特林热机模型进行设计和建模。 相似文献
3.
4.
有着"建筑界特纳奖和布克奖"美誉的斯特林奖是英国建筑界的年度盛事,代表了当今英国建筑设计的最高水平。今年,德国的现代文学博物馆最终击败其他5项入围设计,以其现代与古典融合的设计摘得了2007年的斯特林大奖。 相似文献
5.
6.
对双作用斯特林发动机的活塞和活塞杆的密封结构进行归纳和总结:活塞密封一般采用组合式活塞环或附有涨簧的活塞环,并采用两道密封结构;活塞杆的多种密封方式中,自紧式密封和隔膜式密封应用前景较为广阔.以上结论对双作用斯特林发动机的设计研发具有参考和借鉴作用. 相似文献
7.
8.
本论文对制作的一台新型扩散吸收式制冷机的测控系统进行了设计研究,基于NI产品,结合测控参数特点,选择硬件并进行了安装和调试;编写软件程序,实现了对制冷机工作时的热源温度、发生温度等26个温度点以及制冷机工作时的压力和冷却水流量的在线监测及实时采集,并对所测数据进行存储,以便对数据处理时能够方便调用。 相似文献
9.
10.
本论文对制作的一台新型扩散吸收式制冷机进行了实验研究,研究结果表明,制冷机的制冷效果良好.对热源温度要求降低.当热源温度为72℃时,蒸发温度已达到了50℃,热源温度至78℃时,蒸发温度已至0℃,且来自吸收器的浓溶液和来自发生器的稀溶液的比值的变化对制冷机的制冷效果产生了重要的影响. 相似文献
11.
Chao-Ran Huang Xuzhong Luo Xiao-Gang Chen Xian-Jiang Song Zhi-Xu Zhang Ren-Gen Xiong 《国家科学评论(英文版)》2021,8(5)
Two-dimensional (2D) hybrid organic-inorganic perovskites (HOIPs) have recently gained tremendous interest because of their unique features in contrast to three-dimensional counterparts and traditional 2D materials. However, although some 2D HOIP ferroelectrics have been achieved, the issue of toxic Pb and uniaxial nature impede their further application. Herein, for the first time, we report a lead-free 2D HOIP multiaxial ferroelectric, [3,3-difluorocyclobutylammonium]2CuCl4 (1), which shows four ferroelectric axes and eight equivalent polarization directions, more than those of the other 2D HOIP ferroelectrics and even the inorganic perovskite ferroelectric BaTiO3 (three ferroelectric axes and six equivalent polarization directions). 1 also features a high Curie temperature of 380 K and exhibits remarkable thermochromism of color change from green-yellow to dark brown. To our knowledge, 1 is the first multiaxial lead-free 2D HOIP ferroelectric. This work sheds light on the exploration of better lead-free 2D HOIP ferroelectrics. 相似文献
12.
Domain walls (DWs) in ferroelectrics are atomically sharp and can be created, erased, and reconfigured within the same physical volume of ferroelectric matrix by external electric fields. They possess a myriad of novel properties and functionalities that are absent in the bulk of the domains, and thus could become an essential element in next-generation nanodevices based on ferroelectrics. The knowledge about the structure and properties of ferroelectric DWs not only advances the fundamental understanding of ferroelectrics, but also provides guidance for the design of ferroelectric-based devices. In this article, we provide a review of structures and properties of DWs in one of the most widely studied ferroelectric systems, BiFeO3 thin films. We correlate their conductivity and photovoltaic properties to the atomic-scale structure and dynamic behaviors of DWs. 相似文献
13.
14.
简要评述了陶瓷基板,微波介质陶瓷,铁电压电陶瓷,半导体陶瓷,铁电薄膜和智能材料等功能陶瓷的研究进展和发展趋势,对我院功能陶瓷的发展提出了一些建议。 相似文献
15.
16.
系统研究了晶粒尺寸对铁电性、相结构、晶格动力学和光致发光等性质的影响。研究了择优取向钛锆酸铅铁电薄膜异质结构的取向机理、光学常数以及电学性质,并采用建模的方法分析了影响铁电薄膜红外探测器的因素 相似文献
17.
Peter J. Collings Author Vitae 《Journal of The Franklin Institute》2005,342(6):599-608
In a theoretical examination of the structures of liquid crystal phases, Robert B. Meyer in 1975 creatively utilized symmetry arguments to predict that tilted, layered liquid crystal phases of chiral molecules are ferroelectric. He then engaged the help of organic chemists to synthesize a compound that might possess such a phase, and once the material was in his hands, Meyer not only verified its ferroelectricity, but also suggested how such a phase could be used for extremely fast displays. This discovery of ferroelectricity in a fluid system with the possibility for unique applications surprised the entire condensed matter research community and quickly paved the way for both increased scientific understanding and significant technological advancement. For this creative synthesis of theory and experiment, Meyer was awarded the 2004 Benjamin Franklin Medal in Physics. 相似文献
18.
Cancan Zhang Xiaolei Yu Sujian You Bo Cai Huiqin Liu Lingling Zhang Lang Rao Wei Liu Shi-Shang Guo Xing-Zhong Zhao 《Biomicrofluidics》2016,10(2)
We report on the feasible fabrication of microfluidic devices for ferroelectric polymers'' synthesis in a rapid and stable fashion. Utilizing micro-mixing and flow-focusing in microchannels, poly(vinylidene fluoride-trifluoroethylene) and copper phthalocyanine are uniformly dispersed in one hydrogel particle, which are then demonstrated to immediate and complete on-chip steady polymerization by moderate ultraviolet treatment. The advantage of our droplet-based microfluidic devices is generating versatile particles from simple spheres to disks or rods, and the lengths of particles can be precisely tuned from 30 to 400 μm through adjusting the flow rates of both disperse and oil phases. In addition, this mixed technique allows for the continuous production of dielectric microparticles with controlled dielectric properties between 10 and 160. Such a microfluidic device offers a flexible platform for multiferroic applications. 相似文献
19.
20.
This paper presents solution of the optimal linear-quadratic controller problem for unobservable integral Volterra systems with continuous/discontinuous states under deterministic uncertainties, over continuous/discontinuous observations. Due to the separation principle for integral systems, the initial continuous problem is split into the optimal minmax filtering problem for integral Volterra systems with deterministic uncertainties over continuous/discontinuous observations and the optimal linear-quadratic control (regulator) problem for observable deterministic integral Volterra systems with continuous/discontinuous states. As a result, the system of the optimal controller equations are obtained, including the linear equation for the optimally controlled minmax estimate and two Riccati equations for its ellipsoid matrix (optimal gain matrix of the filter) and the optimal regulator gain matrix. Then, in the discontinuous problems, the equation for the optimal controller and the equations for the optimal filter and regulator gain matrices are obtained using the filtering procedure for deriving the filtering equations over discontinuous observations proceeding from the known filtering equations over continuous ones and the dual results in the optimal control problem for integral systems. The technical example illustrating application of the obtained results is finally given. 相似文献