1W／80K双活塞对置直线驱动斯特林制冷林的研究

介绍一种1W／80K双活塞对置直线驱动斯特林制冷机，它具有振动小，结构紧凑，噪音低，可靠性高等特点。该机在80K时制冷量为1．3W，降温时间小于3.5min（350J热负载）。     

1W/80K双活塞对置直线驱动斯特林制冷机的研究

介绍一种1 W/80K双活塞对置直线驱动斯特林制冷机.它具有振动小、结构紧凑、噪音低、可靠性高等特点.该机在80 K时制冷量为1.3 W,降温时间小于3.5 min(350 J热负载).     

80K/2W斯特林制冷机全性能实验研究

80 K/2 W斯特林制冷机是上海技术物理研究所自行研制的分置式牛津型制冷机.为验证斯特林制冷机在各种工况下的广泛适应性,针对80 K/2 W制冷机进行实验,测试制冷机在不同压缩机行程、制冷温度以及环境温度下的全性能特性,总结斯特林制冷机部分实用的规律.     

低温下Cu-Cu固体间界面热阻的激光光热法研究

以GM制冷机(20K/5W)作为冷源,用激光光热方法对低温下Cu-Cu固体接触界面热阻进行了测量。实验数据表明,在一定的压力(3.0 kPa)和温度范围(20~120 K)内,Cu-Cu接触界面热阻从2.445×10-2m2.K/W减小至3.022×10-3m2.K/W,同时,在一定的温度(80 K)和压力范围(3.0 kPa~0.32 MPa)内,界面热阻从5.547×10-3m2.K/W减小至2.876×10-4m2.K/W。从微尺度的角度对该变化规律进行了机理分析。     

4.2—280K宽温区低温电磁驱动式热开关实验研究

为了在低温温度标定系统中实现超宽温区控温,研制了一种以电磁力驱动的主动机械式热开关,相比常规的气隙式或者材料热胀冷缩式热开关,具有工作温区宽、响应速度快等优点。以一台两级G-M低温制冷机为冷源,搭建了温度低至4.2 K的低温热开关性能试验台。通过升降温过程中的控温对比实验,测得该热开关在50 K时闭合热导为1.5 W/K,断开热导为1.2 m W/K,开关比为1 250;在240 K时闭合热导为0.4 W/K,断开热导为0.5 m W/K,开关比为80。     

线性压缩机驱动的80K单级脉管制冷机设计与实验研究

结合美国标准与技术研究院(NIST)的回热器计算软件REGEN3.2,成功设计了1台单级斯特林型脉管制冷机.采用惯性管调相,在2.5MPa充气压力和60Hz频率下,获得无负荷制冷温度59K.在压缩机输入电功率为250W时,80K获得了3.8W的制冷量,与设计计算结果吻合得较好.     

80K/0.8W星载斯特林制冷机研制

介绍了兰州物理研究所80 K/0.8 W星载斯特林制冷机的研制情况.主要介绍了设计特点、达到的性能指标、通过的环境试验.     

6W@80K气动分置式斯特林制冷机轻量化设计和性能优化

介绍了一台由中国科学院上海技术物理研究所研制的6 W@80 K气动分置式斯特林制冷机样机,主要包括压缩机的轻量化设计和整机制冷性能的优化。该制冷机包括动磁式直线压缩机和气动膨胀机,制冷机整机质量为5.5 kg。压缩机采用两个对置布置的动磁式直线电机驱动,板弹簧支撑和无摩擦的间隙密封技术。经过对直线压缩机的结构优化,在6 W@80 K的制冷性能下,压缩机的输入电功从原来的163 W降低到106 W。     

斯特林型高频脉冲管制冷机的实验研究

介绍了一台单级U型高频脉冲管制冷机的实验装置和实验结果.制冷机冷端无负荷最低温度达到了38.31 K,此结果为目前国内单级斯特林型高频脉冲管制冷机所达到的最低温度.当输入电功率200 W时,在50 K有0.6 W制冷量;当输入电功率为250 W时,在80 K有4.25 W的制冷量.这为40 K以下深低温,大冷量的斯特林型脉冲管制冷机的研制做出了有益的探索.通过分析压缩机运行频率对制冷机的最低温度和制冷量的影响,得出了在液氮温区针对特定的制冷温度,压缩机存在的一个最佳工作频率.在此工作频率下,压缩机和脉冲管耦合后,制冷机能够获得较高的效率.     

瑞士苏尔寿公司制造的TFC100型透平式制冷机

TFC100型透平式制冷机是为研究中心及大学用的一种标准式的氦液化器与氦制冷机。根据构件标准,它是由两台无润滑压缩机和一只冷箱组成,生产能力可以从10升液氦/时(40W,4．5K)至 80升液氦/时(18W,4．5K)之内进行变工况生产。立式冷箱与控制箱     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.