涡流制冷方式在工业领域的应用

涡流管是利用一种能够把压缩气体分离为冷热两股温度不同气流的简单装置。由于这种装置具有结构简单、工作稳定可靠、易于维修、无运动部件且温度变化范围大等优点,已被应用到许多工业领域。     

新控制方式前向波放大管

前向波放大管作为一种微波功率放大器件,在雷达领域具有重要的用途。本文提出了一种新的直流应用前向波放大管控制方式,这种控制方式有助于提高前向波放大管的稳定性和可靠性。     

低温等离子体去除室内气态污染物的发展现状

本文介绍了室内气态污染物的来源和特点,阐明了等离子体的概念、存在状态以及分类,列举了低温等离子体的制备方法、部分化学反应的机理以及在去除室内空气污染物方面国内已取得的成果,并提出了今后需要进一步研究的问题。     

基于涡流管能量分离效应的温度分布实验研究

在入口温度、压力不变的条件下,改变冷流比,分别对不同冷流比工况下的涡流管内温度分布进行了实验测试,同时对不同冷流比工况下的实验结果进行比较,研究表明:在同一轴向端面处,温度由轴心向壁面呈现不断增大的趋势,在壁面附近处达到最大值;在同一径向位置处,温度随着轴向位置的增大不断增大,在涡流室的轴心处,温度达到最低,而在热端出口的壁面处,温度达到最大。在冷流比为0.1563时,温度沿径向呈增大趋势,而在冷流比为0.7158时,温度沿径向呈现先降低后增大的趋势;在实验研究范围内,同一测点处,温度随冷流比的增大而增大。     

全数字直流调速装置在冷弯机组上的应用

介绍了全数字直流调速器SIMOREG K 6RA28的技术特点和工作原理，以及在冷弯机组上的应用，关键元器件的选择、现场安装、调试、维护方法等。     

一种新型的热电偶冷端补偿器件

本文介绍采用一种新型集成半导体温度传感器ＡＤ５９０作为热电偶冷端补偿的原理、线路及其优点。以一个集中温度控制系统为例说明它的使用。     

MUT of a one out of two system with preventive maintenance

We are interested in the MUT (Mean Up Time) of a one out of two system in cold standby with preventive maintenance: a preventive maintenance occurs when the working unit reaches a given age. We study in details the stationary distribution of the Markov chain describing the state of the system at the beginning of its working periods. We give exact analytical formulas from which we derive a way to compute the MUT and we compare the results with those of Smith and Decker [M.A.J. Smith, R. Decker, Preventive maintenance in a 1 out of n system: The uptime, downtime and costs, European Journal of Operational Research 99 (1997) 565–583] which are based on approximations. We also investigate some discontinuities problems.     

工艺参数对激光切割工艺质量的影响

对汽车用冷轧钢板进行了激光切割工艺试验,研究了激光切割速度与激光功率对切缝宽度、表面粗糙度、挂渣等切割质量的影响。结果显示在相同的条件下,切缝宽度随切割速度的增加而有一定的变化,随激光功率的增加而显著增加。切割速度及激光功率对切割表面粗糙度的影响是一抛物线规律,随切割速度的变化,切割边部形貌存在分形现象。金属材料激光切割后其热影响区非常小,受激光切割工艺参数的影响不大。     

Test of cold denaturation mechanism for proteins as a function of water's structure

At low temperatures and high pressures (ranging from approximately 200 up to 700 MPa), some proteins become thermodynamically unstable by means of a phenomenon know as cold denaturation. A microscopic understanding of the mechanisms leading to cold denaturation is very difficult to develop, due in part to the complexity of the protein–solvent interactions. A possible proposal to explain the cold denaturation of proteins based on a relation between hydrophobicity and the loss of the local low-density water structure at high pressures is explained in detail. In the present paper, this mechanism is tested for the first time by means of full atom numerical simulations. In good agreement with the proposal, cold denaturation resulting in the unfolded state has been found at the high-density liquid (HDL) state of water, at which the amount of open tetragonal hydrogen bonds decreases at cooling.     

Direct quantification of ethyl carbamate in distilled alcoholic beverages using a cold capillary injection system and optimised selected ion monitoring

Summary An integrated procedure is described which allows direct injection quantitative screening to single figure parts per billion (g/L) levels of ethyl carbamate in the natural matrix of distilled alcoholic beverage. Injection and detection performance was studied and optimized to allow this routine, reproducible, trace analysis without any sample pre-treatment. All aspects of the analysis including autosampler run sequences and automated internal standard report generation are initiated and controlled from a single GC/MS workstation.Excerpt from the Ph. D. Thesis (in preparation) of K. MacNamara, Universität Karlsruhe