水冷式半导体冰箱制冷性能的研究

研究了水冷式散热方法对半导体冰箱制冷性能的提高.以常用的半导体小冰箱为实例,分别测试了在风冷、循环水和恒温水条件下小冰箱的制冷性能.结果表明,水冷制冷效果明显优于传统风冷式,且其制冷性能与冷却水的温度有关.水温越低,半导体制冷器的制冷效率越高,制冷温度越低.当冷却水温度为171 ℃时,水冷半导体小冰箱很快达到冷冻.建立了水冷式半导体冰箱的制冷模型,计算分析了在不同恒定冷却水温度下半导体制冷器冷端温度随时间的变化关系,并将理论结果与实验测量结果进行了拟合分析,发现理论模型与实验测量结果一致.研究结果为水冷式半导体冰箱制冷性能的提高提供了实验和理论依据.     

二甲醚作为冰箱制冷剂的理论分析

对二甲醚（DME）用作冰箱制冷剂进行理论分析，比较制冷剂DME与冰箱制冷剂HFC134a和HC600a的基础热物理性质。对它们的冰箱标准工况制冷循环性能和变工况制冷循环性能进行理论计算及分析。分析表明：制冷剂DME的制冷性能与HFC134a和HC600a的制冷性能基本相似，性能系数（COP）却优于HFC134a和HC600a。并且，二甲醚具有环保、无毒和与材料兼容的特点。因此，二甲醚适合做新一代的冰箱制冷剂。     

三氟甲醚作为冰箱制冷剂的理论分析

对氟化醚类工质三氟甲醚(简称HFE143a)用作冰箱制冷剂进行了全面的理论分析。首先比较了新制冷剂HFEl43a和冰箱制冷CFCl2、HFCl34a和HFCl53a／HCFC22等的基础热物理性质。然后对它们的的冰箱标准工况制冷循环性能和变工况制冷循环性能进行了详细的理论计算及分析。分析表明：适应更高环境保护要求的HFC143a完全适合做新一代冰箱制冷剂。     

基于镍钛片的弹热冰箱设计与仿真研究

弹热制冷通过单轴应力驱动弹热工质发生相变而产生制冷作用,由于其具有较高的理论制冷效率且温室效应为零,因此被认为是一种替代传统蒸气压缩式制冷的新型固态相变制冷技术。本研究团队从提升弹热原型机紧凑型角度出发,已研发了两代基于拉伸镍钛丝的弹热冰箱。为进一步提升弹热冰箱的制冷性能,本文使用镍钛片替换镍钛丝作为弹热工质,设计了第三代弹热冰箱,并构建系统仿真模型。通过仿真预测了第三代弹热冰箱的性能,结果表明：相较于前两代弹热冰箱,性能均有提升。在绝热工况下,第三代弹热冰箱将能够实现12℃的制冷温差,在热端散热工况下,弹热冰箱能实现11.4℃的冷端温降以及零温差下0.59 W/g的制冷功率。通过增加拉伸应变、更换潜热更大厚度更薄的弹热工质以及增大电机转速,弹热冰箱在32℃环温条件下能够维持10.7℃的冷藏温度。     

多点制冷性能检测系统的设计及应用

制冷性能检测是制冷设备生产完成后必须进行的一个主要检测项目．针对制冷产品中小型生产企业,设计了一次可完成2048个检测点的多点制冷性能检测系统．整个系统主要由制冷产品测试线、64路温度巡检仪和上位机组成,说明了这3个组成部分的设计及实现方法,对实际检测电冰箱得到的温度曲线和在实际应用中出现的问题进行了分析说明．目前该系统已经应用到浙江省部分冰箱、冷柜制造企业中。     

小型制冷压缩机

小型制冷压缩机是小型制冷机的心脏。近几十年来,小型制冷压缩机的结构大约15年左右更换一次。转速也一再增加,产量也逐年增,在第二部分综述了制冷压缩机的主要型式.按电动机安装方式可以分为封闭式、半封闭式和开启式三种;按结构形式来分可以分为活塞式、回转式和螺杆式三种.按制冷剂种类可以分为氟里昂、氨、氯甲烷、二氧化硫几种。在第三部分简要介绍了主要的制冷剂的性能.在第四部分以小型制冷压缩机的典型代表—冰箱压缩机为例介绍了连杆式、滑管式、滚动活塞式三类冰箱压缩机的特点.最后介绍了目前国内外冰箱压缩机的生产情况.     

旋转压缩机在冰箱、空调器上的应用

制冷压缩机是冰箱、空调器制冷系统的心脏,它的性能优劣直接影响到冰箱、空调器的性能。在60年代以前冰箱和空调器普遍使用往复式压缩机(冰箱多采用滑管式压缩机)。60年代开始旋转压缩机在美国研制成功,接着日本亦迅速发展     

家用冰箱制冷循环的热力学第二定律分析

本文从热力学第二定律出发。给出了制冷循环的熵分析方法;分别以HFC—134a和CFC—12作为制冷工质。讨论了家用冰箱制冷循环的不可逆性;并根据熵分析结果,计算了循环的性能系数,与性能系数的理论值进行了比较。     

国外吸收式冰箱生产情况

吸收式制冷在冰箱制冷技术的产品中占有不太大的比例,各国产品数量约占其总产量的5～10％。欧洲现在每年生产的吸收式冰箱超过130万台。吸收式冰箱生产厂家大部分在西欧,主要厂家有瑞典的叶列克托柳克斯,瑞士的西比尔     

冷藏柜用制冷压缩机通过鉴定

湖北省黄石市制冷设备厂从意大利阿斯贝拉公司引进冷藏柜和大规格冰箱用“E”系列制冷压缩机全套生产加工设备,可生产7种规格压缩机,制冷量范围在147W至388W。该厂生产的QD90(E1116C)制冷压缩     

炮射导弹测试弹技术探讨

本文将介绍炮射导弹的发展史,研究炮射导弹测试弹的迫切性,以及我们对炮射导弹测试弹技术方案的初步探讨。     

Some findings on the usefulness of image analysis for determining the characteristics of the air-void system on hardened concrete

This paper discusses the usefulness of image analysis techniques in order to assess the characteristics of the air-void system in concrete. Test results indicate that such a technique can correctly assess the air-void characteristics as defined in ASTM C 457 Standard test method. However, the accuracy of the test results is not significantly improved as compared with the manual technique and the image analysis method must be very carefully validated before being used as a routine procedure. Test results also indicate that the image analysis technique failed to correctly assess the size-distribution of air voids and, for that reason, this technique cannot be used to provide a better estimate of the real spacing of air voids than the commonly used ASTM C 457 spacing factor.     

某型涡扇发动机试车台测试系统研制

结合某型高推重比涡扇发动机试车合测试系统的研制，介绍了该系统的技术指标、数据采集技术、显示技术和试车仿真原理。为提高系统测量精度和使用性能，提出并应用了测量参数非线性修正、多模式显示、实时发动机参数整理等技术。     

Application of the reference stress method for interpreting impression creep test data

Impression creep tests have been performed on a 316-stainless steel at 600°C, for which conventional uniaxial creep test data are available. It is shown that the technique, based on the reference stress approach, for converting impression creep test data to equivalent uniaxial creep data, is accurate. The results show that the impression creep technique can be used for obtaining creep properties for materials which have high creep resistance at high temperature and test pressure conditions. The difficulties and limitations associated with such situations are described and methods of dealing with them are outlined.     

Optimisation of a salt deposition technique for the corrosion-fatigue testing of nickel based superalloys

This paper summarises the work undertaken to develop a salt deposition technique that can be utilised for hot corrosion and high temperature corrosion-fatigue testing of high performance alloys for gas turbine application. The optimisation process has yielded a new method of application of a sodium sulphate based solution to various test piece geometries. The technique employs the use of a micro-pipette to deposit a pre-calculated solution, consisting of methanol, water, Na₂SO₄–NaCl onto preheated specimens, in preparation for corrosion testing. This optimised salting technique has reduced the variability in the salting of test specimens, when compared with existing salt spray methods and has therefore enabled test repeatability along with an associated significant reduction in scatter within high temperature corrosion-fatigue results.     

Application of the Blister Test in Study of Epoxy Adhesive

Shaft-loaded blister test technique is used as an effective quantitative tool to measure adhesion strength. Investigation on conductive adhesive was done by modified blister test. It is found that shaftloaded blister test can be a good solution for the debonding of thin film adhesion. The intrinsic stable interface debonding process has been proved an attractive alternative to the conventional adhesion measurement techniques. In our study, epoxy matrix adhesive was studied using blister test technique in comparison with the traditional test-lap shear test. Adhesion strength was studied as a function of surface treatment and the metallization of substrate. It was found that surface conditions of substrate have significant impact on adhesion behaviour. The oxidation of surface is responsible for the poor adhesion. Activating chemical treatment and Plasma cleaning on substrate surface has been found to be a way of dreamatically improving adhesion strength of electronic conductive adhesive.     

Convergence of the discrete dipole approximation. II. An extrapolation technique to increase the accuracy

We propose an extrapolation technique that allows accuracy improvement of discrete dipole approximation computations. The performance of this technique was studied empirically on the basis of extensive simulations for five test cases using many different discretizations. The quality of the extrapolation improves with refining discretization, reaching extraordinary performance especially for cubically shaped particles. A 2-order-of-magnitude decrease of error is demonstrated. We also propose estimates of the extrapolation error, which are proven to be reliable. Finally, we propose a simple method to directly separate shape and discretization errors and illustrate this for one test case.     

20.4K冷氦加温及氧箱的模拟增压试验技术

主要介绍２０．４Ｋ低温氦气经过加温后给液氧贮箱增压的试验技术。对试验设备、试验方法、试验过程及试验结果做了简要的介绍。     

三种方法检测水中总大肠菌群的比较探讨

采用多管发酵法、滤膜法及酶底物法三种方法同时检测水中总大肠菌群,并对结果进行比较分析,结果表明三种方法各有优劣,我们在实际检测工作中,应根据需要,采用不同的检测方法,使结果更加准确可靠。     

A rapid technique for assessing the moisture ingress susceptibility of plastic-encapsulated integrated circuits

The equipment and associated methodology of a new technique for checking the susceptibility of plastic-encapsulated ICs to moisture ingress is presented. The basis of the new technique is to immerse unbiased ICs in a salt solution and to subject them to high temperatures (in the range 120°C to 175°C) and to high pressures (2 to 9 atmospheres). At the highest temperature, results can be obtained within a few hours, although a 20 h test at 165°C is suggested as a screen for components. The test is extremely simple to carry out and a testing facility can be quickly established. Using CMOS components from five different vendors, good agreement has been obtained between the results from the new test and the results from a biased 85°C/85 percent RH test.