大冷量新型蓄冷材料G-M制冷机的研究进展及应用

随着大型低温真空泵、高低温超导器件、核磁共振成像仪、红外探测器、低温光电子学器件的迅速发展,以及作为传统蓄冷材料的铅(Pb)等有害物质的限制使用,对大冷量新型蓄冷材料G-M制冷机的发展提出了迫切的需要。文中主要介绍国内外大冷量G-M制冷机及新型磁性蓄冷材料的最新研究进展和应用情况,并提出了下一步的研究方向。     

泰勒斯低温技术公司线性斯特林制冷机发展现状

对泰勒斯低温技术公司线性斯特林制冷机的发展现状进行总结.分别对其线性斯特林制冷机压缩机技术发展、膨胀机技术发展、膜片弹簧设计原则和可靠性增长等方面进行了总结.     

5W@77K气体轴承斯特林制冷机研究

气体轴承斯特林制冷机是相同制冷量中体积最小、重量最轻、效率最高及寿命最长的制冷机。对于小型化的5W@77K型气体轴承斯特林制冷机,以其独特的优势,在高温超导、低温制冷与深空探测等领域,赢得了广泛的需求。因此,基于redich线性电机形式,运用气体轴承支撑技术和高效回热器技术,国内首次研制成功了小型化气体轴承斯特林制冷机,为我国的低温制冷领域的发展提供坚实的基础。     

脉管制冷机振动的形成机理及减振方法研究

振动水平是低温制冷机的重要性能指标之一,而振动问题往往是低温制冷机应用于冷却敏感仪器的最主要瓶颈。系统介绍了低温制冷机的振动测量方法和振动形成机理的研究进展,并对目前低温制冷机的主要减振措施进行了整理与归纳。还对目前低温制冷机减振措施中存在的问题和发展趋势做了探究。     

直线压缩机驱动热声型低温热声制冷机研究

直线压缩机驱动的热声型低温热声制冷机是获得低温的一种重要制冷技术,它利用直线压缩机往复运动产生的声波驱动脉管产生热声制冷效应而工作。文中报道了由中国科学院理化所和深圳市中科力函热声技术工程研究中心联合研制的系列液氮温区低温热声制冷机,其效率达到22%,为目前国际上所有公开报道的各类热声制冷机中的最高效率。该系列低温热声制冷机在低温下无运动部件、可靠性高,在红外探测器、高温超导滤波器等低温电子器件冷却方面具有重要应用前景。此外,还将对下一步的研究进行简单的介绍。     

用脉管制冷机作为低温泵冷源的可行性分析

首先简要的介绍脉管制冷机的发展历史 ,现有的一些类型 ,列出一些产品的具体性能参数 (包括所能达到的最低温度 ,制冷量等 )。然后根据制冷机低温泵现有的技术 ,通过比较来综合说明选择脉管制冷机来替代其它小型低温制冷机的可能性及优势 ,得出结论 ,脉管制冷机用作低温泵冷源是可行的     

混合工质在低温制冷中的应用

简单介绍了混合工质的特点,分别就混合工质在节流制冷机、回热式制冷机中的应用做了阐述,总结出混合工质对低温制冷机性能的提高有显著作用,其发展空间广阔.     

低温VM制冷机实验研究进展

VM制冷机是一种结构紧凑的热驱动斯特林型制冷机,主要靠工作热源间的温差在系统内产生制冷所需压力波动。通过对系统内部往复运动的排出器设置合适的相位角,VM制冷机可以实现从高温热源和低温热源吸热,向中间热源放热。此外,VM制冷机还具有磨损和振动小、寿命长等优点。到目前为止,气耦合脉冲管型的两级VM制冷机已经能够获得2.49K的无负荷温度,在4.2K可提供36m W制冷量。在总结单级和多级低温VM制冷机的实验进展的基础之上,进一步探讨了低温VM制冷机的应用领域,为低温VM制冷机的发展及实际应用提供了参考。     

小型低温透平制冷机中电动机和发电机的应用

介绍了低温领域中小型透平制冷机应用的电动机和发电机,列举了四种主要的应用型式,即:小型制冷机中应用电机驱动压缩机;透平膨胀机中采用发电机制动;发电机吸收同轴膨胀机增压机功差以及电动机发电机两用电机.同时探讨了微型制冷机领域对低温电机的特殊要求及其发展方向.     

80K高频无磁非金属脉冲管制冷机

介绍了高频脉冲管制冷机冷指无磁非金属材料的选择、加工以及实验优化工作.制作的高频无磁脉冲管制冷机冷指在风冷,2.3 MPa 充气压力,44 Hz,70 W 电功率输入条件下,最低达到 73.4 K 的无负荷最低温度;60 W 电功率输入,最低温度为 74.0 K,在 80 K 时可以提供 0.1 W 的制冷量.本文为高频脉冲管制冷机直接冷却相关低温超导器件提供了坚实的基础.     

一种新型冷头结构的微型同轴脉管制冷机的实验研究

许多现代电子器件的正常运行都需要一种紧凑型、高可靠性,低耗能的微型机械制冷机进行低温冷却。针对这种需求,文中提出了一种新型整体式冷头结构,该冷头结构大大增强了工作气体与冷头换热器的换热能力。详细描述了一种由7.0 cc扫气容积对置式双活塞线性压缩机驱动的具有这种新型冷头结构的微型同轴脉管制冷机的性能实验研究。     

Femtosecond semiconductor-based optoelectronic devices for optical-communication systems

Compact semiconductor-based ultrafast optoelectronic devices are crucial for networks with a throughput in the 1–10 Tb/s range. A variety of ultrafast phenomena in semiconductors are attractive for developing such new optoelectronic devices. This paper discusses the requirements of ultrafast optical-communication systems and necessary optoelectronic devices. Recent progress of ultrafast semiconductor-based optoelectronic devices are described with a focus on all-optical switching devices, including novel devices using electron spin polarization relaxation and intersubband transition both in multiple quantum well structures.     

A simple encapsulation method for organic optoelectronic devices

The performances of organic optoelectronic devices, such as organic light emitting diodes and polymer solar cells,have rapidly improved in the past decade. The stability of an organic optoelectronic device has become a key problem for further development. In this paper, we report one simple encapsulation method for organic optoelectronic devices with a parafilm, based on ternary polymer solar cells(PSCs). The power conversion efficiencies(PCE) of PSCs with and without encapsulation decrease from 2.93% to 2.17% and from 2.87% to 1.16% after 168-hours of degradation under an ambient environment, respectively. The stability of PSCs could be enhanced by encapsulation with a parafilm. The encapsulation method is a competitive choice for organic optoelectronic devices, owing to its low cost and compatibility with flexible devices.     

Issues in the realization of strained-layer quantum well optoelectronic devices

Ion-beam processing is the ideal complement to modern lattice-mismatched (strained-layer) heteroepitaxy for optoelectronic device fabrication. Bandstructure engineering of optoelectronic devices through the use of lattice strain is presented, and the effects of ion-beam processing on III–V strained-layer heteroepitaxial structures are summarized. Representative results from ion-implanted optoelectronic devices are presented to illustrate these principles.     

Microwave and millimeter-wave losses in conventional optoelectronic devices

In this paper, microwave characteristics of conventional optoelectronic devices, with emphasis on devices with microstrip (MS) and coplanar waveguide (CPW) electrode structures, are obtained. This analysis is essential for any improvement in the structure of the conventional optoelectronic devices so as to obtain a high performance. Microwave loss is one of the important bandwidth limitation factors in microwave and millimeter-wave (mmW) optical devices. Different sources of loss including ohmic, dielectric and radiating loss in MS and CPW of conventional optical devices are analyzed and compared. The results show that the total microwave loss increases with frequency in conventional MS and CPW waveguides. Also, in traveling-wave optoelectronic devices, the bandwidth is limited in the optical part by effects such as the carrier transit time effect and in the microwave part by factors such as length of the devices in active and non-active sections. In addition, validation of the results in the paper is performed with published theoretical and/or measurement results.     

Low crosstalk monolithic wavelength demultiplexing switch arrays

Wavelength Division Multiplexing (WDM) is a key enabling technology for increasing the transmission capacity of optical fiber communication systems. Recently, a new family of optoelectronic devices, including detectors, switches, and emitters, that is based on resonant cavity enhancement, has emerged. Wavelength selective optoelectronic switching is achieved by placing a photothyristor in an asymmetric Fabry-Perot cavity, which provides a highly selective response at a wavelength determined during device fabrication. These WDM optoelectronic devices haue promising applications in optical COmmunications and optical logic circuits. Results on a N-p-n-p optoelectronic switch with a ten wavelength channel capability are presented.     

Two-dimensional optoelectronic devices for future optical switching and information processing

Recent progress is reviewed in surface-normal optoelectronic devices primarily for use in optical switching and information processing. A type of optoelectronic integrated circuit (OEIC), the surface-normal two-dimensional array, is fabricated using these devices. This improves on first-generation OEICs by featuring large-scale integration in a small area, which results in a higher production yield. It also has structures which can easily be integrated with electronic circuits and can meet multichannel requirements. This approach supports optoelectronic progress towards optical information processing.     

半导体材料的华丽家族—氮化镓基材料简介

GaN基氮化物材料已成功地用于制备蓝,绿,紫外光发光器件,日光盲紫外探测器以及高温,大功率微波电子器件,由于该材料具有大的禁带宽度,高的压电和热电系数,它们还有很强的其他应用潜力,诸如做非挥发存储器以及利用压电和热效应的电子器件等,在20世纪80年代末和90年代初,在GaN基氮化物材料的生长工艺上的突破引发了90年代GaN基器件,特别是光电子和高温,大功率微波器件方面的迅猛发展,文章评述了GaN基氮化物的材料特性,生长技术和相关器件应用。     

半导体量子器件物理讲座第七讲半导体异质结光电探测器

光电探测器是一类用于接收光波并转变为电信号的专门器件，文章描述了PIN光电二极`管雪崩光电二极管、MSM（金属－半导体－金属）光电二极管的器件结构和工作原理，并对它们的响应度、噪声、带宽等特性进行了讨论，这类器件已在光通信、光信息处理等许多系统中得到广泛的应用。     

A reproducible route to p-ZnO films and their application in light-emitting devices

Although great efforts have been made, reproducible p-type doping is still one of the largest hurdles that hinders the optoelectronic applications of ZnO. In this Letter, a reproducible route to p-type ZnO films employing lithium-nitrogen as a dual-acceptor dopant has been demonstrated, and p-i-n structured light-emitting devices (LEDs) have been constructed. Obvious purple emissions have been observed from the LEDs, confirming the applicability of the p-type ZnO films in optoelectronic devices. The results reported in this Letter provide a reproducible route to p-type ZnO films, and thus may lay a solid ground for future optoelectronic applications of ZnO.