Experimental study of the airside performance for interrupted fin-and-tube heat exchanger with hydrophilic coating under dehumidifying conditions

The airside heat transfer and friction characteristics of seven interrupted fin-and-tube heat exchangers with hydrophilic coating under dehumidifying conditions are experimented. The effects of number of tube rows, fin pitch and inlet relative humidity on airside performance are analyzed. The test results show that the influence of fin pitch on the friction characteristic under dehumidifying conditions is similar to that under dry surface, and the friction factors decrease slightly with the increase of number of tube rows. The heat transfer performance decreases as fin pitch and number of tube rows increases. The heat transfer performance and the friction characteristic are independent of inlet relative humidity. Based on the test results, heat transfer and friction correlations in terms of the Colburn j factor and Fanning f factor, are proposed to describe the airside performance of the interrupted fin geometry with hydrophilic coating under dehumidifying conditions. The correlation of the Colburn j factor gives a mean deviation of 9.7%, while the correlation of the Fanning f factor shows a mean deviation of 7.3%.     

Two Phase Pressure Drop Performance of Refrigerant in a Small Horizontal Smooth Tube with 2.5 mm inside Diameter

Two-phase flow pressure drop measurements were made during the phase change heat transfer process of R22 in a small horizontal smooth tube with 2.5 mm inside diameter. Conclusions can be drawn that the quality corresponding to the pressure gradient peak value of small tubes became higher than that of large tubes. The effect of quality to pressure drop becomes weak as the mass flux increases. The experiment data were compared with the predicated values of the state-of-the-art correlations from the open literature. The comparisons between the data and the predictions indicate that most of the state-of-the-art correlations fails to predict the experimental data.Chisholm model shows a relatively better predictive ability than the other empirical correlations although it has a mean deviation of 26.7%. But the predicated values of Chisholm model are lower by 50% than the experimental data when the quality becomes larger.     

辊杆冷水机组启动过程的仿真

螺杆冷水机组在中央空调系统中得到越来越广泛使用，为预测螺杆冷水机组启动过程的特性，建立了动态仿真模型，仿真结果表明，模型定性合理，相应的仿真软件可以帮助设计人员优化产品设计，或作为机组维修或操作人员低成本，高效率的培训工具。     

人在体心内膜除极与复极关系的研究

应用Franz接触电极记录室内传导正常的人左室内膜单向动作电位（MAP），观察心内膜激动时间（AT）、动作电位时程（MAP），复权时间（RT）及其关系。结果：①AT与APD呈显著负相关，平均相关系数为-0．87±0．07（P均＜0．05）；②空间隔、心尖部、侧壁及基底部AT分别为26±6、29±4、39±4和44±2（ms）；③多数部位的AT间和APD间有显著差异，而RT间无显著差异。结论：①心内膜中激动早的部位APD较长，激动晚的部位APD较短；②激动较早的部位为空间隔和心尖部，较晚的部位为例壁和后基底部；③正常心内膜复极投除极具有较强的均一性。     

The Effect of Circulation Fan on Energy Consumption in Nature Convective Refrigerator-Freezer

The effect of the circulation fan installed in fresh food compartment on energy consumption of natural convective refrigerator/freezers (RFs) was experimentally studied. Five different RF models with different cycles were tested. The experimental results showed that the energy consumption of the single-loop cycle RF increased by 2.4%~3.8%, that of the bypass two-circuit cycle RF decreased by 1.0%, and that of the two-circuit cycle RF with its evaporators in parallel when the geometry parameters of refrigeration system and the refrigerant charge were not changed after the circulation fan was installed decreased by 3.3%. When the optimization on the refrigerant charge and the evaporator was carried out, the energy consumption of the single-loop cycle RF , the bypass two-circuit cycle RF and the two-circuit cycle RF with its evaporators in parallel, decreased by 1.0%~6.4%, 3.25% and 3.26% respectively. The present conclusions will provide a guideline to the optimum design for the RF with the circulation fan.     

A New Experimental Rig of Testing Flow Boiling Heat Transfer of Refrigerant and Lubricant Mixture

This paper proposed a new experimental rig of testing flow boiling heat transfer of refrigerant and lubricant oil mixture. The quantity of oil in the test section can be controlled and regulated conveniently and accurately by connecting separate lubricant oil circuit with test section in parallel. It was built up by retrofitting a multiple air-conditioner and installing three oil-separators in serials at the compressor outlet. And so the lubricant oil in the discharged refrigerant gas of compressor can be removed completely. The refrigerant flow rate through test section can be bypassed by the by-path circuit of indoor unit. This experimental rig has advantages such as on-line and continuous oil injection, short time of obtaining stability, flexible operation, simple control, which lead to high efficiency in the research of flow boiling heat transfer of refrigerant and lubricant oil mixture.     

基于DSP的移动电站检测系统设计与实现

介绍一种基于数字信号处理器（DSP）的移动电站检测系统。系统采用主从式总体结构，以TMS320LF240为核心，通过A／D转换电路和DSP同步采样控制，实现多种移动电站电量信号的采集与处理。     

多量程电力传感器的设计与实现

介绍一种采用电流、电压互感器实现的多量程电力传感器，并对系统结构、信号放大电路、单片机测控和调试要求提出了有效的实现方法。     

我国汽车自主品牌发展需靠政策支持

2011年我国自主品牌汽车销售困难,遭遇到了前所未有的成长烦恼。我国汽车产销量已连续两年位列世界第一,每年达1800万辆以上。2011年汽车产销量仍有可能接近或超过2000万辆。汽车制造大国要成为汽车出口大国、汽车工业强国,很重要的一点,是拥有汽车自主品牌,甚至是名牌,靠自主品牌的崛起和强盛占领世界市场,成为汽车创新强国。我国已有一批自主品牌,上汽荣威和MG、奇瑞、吉利、比亚迪等,迈出了可贵的第一步,但离"强势自主品     

脐血浆内源性类洋地黄物质的部分纯化与鉴定

选用Ｃ１８预处理柱分离脐血浆内源性类洋地黄物质（Ｅｎｄｏｇｅｎｏｕｓｄｉｇｉｔａｌｉｓ－ｌｉｋｅｓｕｂｓｔａｎｃｅ，ＥＤＬＳ），应用高效液相色谱分析法（ＨＰＬＣ）对其进行部分纯化，观察部分纯化的ＥＤＬＳ对红细胞摄取８６Ｒｂ的抑制作用，并比较其与哇巴因在高效液相色谱图上的特点。结果表明：脐血浆第二份ＨＰＬＣ洗脱液（滞留时间４～６ｍｉｎ）对红细胞摄取８６Ｒｂ具有强烈的抑制作用；其抑制率为（８９±３）％，明显高于其它洗脱物份别及孕妇、健康成人对照组血浆第二份洗脱物的抑制率［分别为（７３±５）％和（４３±３）％，Ｐ值均＜０．０１］；部分纯化的ＥＤＬＳ、哇巴因及两者混合物的滞留时间基本一致，提示ＥＤＬＳ与哇巴因的结构相似。