低温压力传感器自动检定/校准装置设计

设计研制了一套可在低温环境下检定/校准压力传感器的装置.该装置采用模块化设计方法,各模块可独立使用,从而提高了低温压力传感器自动检定/校准装置的使用效率.该装置的工作温度可以从室温到-196℃,期间温度可连续变化,压力范围为0～ 20MPa,检定/校准装置的扩展不确定度为0.1％(k=2).该检定/校准装置的建立,有效地保证了我国航天液体火箭发动机试车所用低温压力传感器液氧管路系统压力测量的准确性,也保证了发动机性能评估的可靠性及故障诊断的准确性.     

用于低温压力传感器校准的低温工作环境的研制

针对航天液体发动机试验用低温压力传感器的真实工况下校准等问题,设计了用于低温压力传感器校准的低温工作环境装置。该装置采用PID控制技术和低温、高压、真空耦合环境密封技术,可以提供温度可控、温区连续、超大温度范围的低温环境(-196～20℃)。实验结果表明,该环境装置能够达到设计要求,可同时对多个低温压力传感器校准。     

20—80K低温压力传感器校准系统的研制

针对低温压力传感器的精确测量,设计并搭建了一套20-80 K低温压力传感器校准系统,介绍了系统中恒温试验腔的原理、结构及连接方式,验证了恒温试验腔内温度场的均匀分布。恒温试验腔完全浸没在液氢中,通过温度控制系统调节腔内电加热丝功率,来实现对测试环境温度的控制。试验结果表明,该系统结构紧凑,安全可靠性高,性能稳定,测试温区内变温有良好的温度梯度,温控精度在±0.2 K以内,可通过压力标准源对安装在恒温试验腔内的低温压力传感器进行精确校准。     

液氧煤油发动机地面试验低温压力传感器校准系统设计

为获得不同环境温度下低温压力传感器的校准系数,提高压力测量的精度,着重介绍低温压力传感器校准系统设计,该校准系统具备温度自适应调整功能,为低温压力传感器校准提供温区连续、大范围温度可控的温度环境以及稳定可调的压力源,在一定程度上消除温度环境因素对传感器灵敏度的影响。通过低温压力传感器现场校准测试,获得压力传感器在不同温度环境下的工作特性并掌握其随温度变化的规律。     

电容式密度传感器低密度液氢校准实验研究

设计、搭建了一套可调节密度式多点电容式密度传感器校准装置,并进行了电容式密度传感器低密度液氢的校准试验。实现了对液氢在一定低密度范围内(50—70kg/m3)的调节,突破了传统的常压单一密度点校准技术,实现了液氢多密度点的校准,提高了校准结果的可靠性。对电容式密度传感器校准装置各因素引入的不确定度分量进行了评定,分析得到了该装置的不确定度,试验结果表明采用给液氢增压的方式可以对液氢低密度进行准确控制,该调节装置的不确定度满足电容式密度传感器校准设计要求,并且能够对电容式密度传感器在多种低温流体介质中进行较宽密度范围校准。     

浮空器艇载传感器在线校准技术研究

随着浮空器智能化程度越来越高,艇体所使用的传感器种类和数量也越来越多,这其中以压力传感器为主.在浮空器进行试验前有必要对传感器进行快速校准,已有的校准装置都是实验室用的单类型传感器校准装置,既不能同时校准多类型传感器,也不能用于实验室以外的现场校准.因此,为确保浮空器研制任务的顺利进行,研究与开发浮空器艇载传感器在线校准装置,实现艇载传感器的高效、快速校准,成为了浮空器研制过程中的紧迫任务.     

低温温度计及温度传感器校准装置研究

针对目前低温温度计及温度传感器的校准现状,采用液氮制冷的方式研制了一套低温恒温装置,该装置的设计指标为均匀性10 mK,稳定性5 mK/20 min,可连续变温范围为78～200 K,完全可以满足83～193 K温度范围内各种结构尺寸的工业低温温度计和温度传感器的校准要求,填补了国内在此温区范围内无法实现对低精度温度计的比较法校准的空白.     

CGY-450高压传感器校准装置研制与应用

在防护工程和爆炸与冲击等研究领域,压力测量的范围越来越大,数百兆帕的压力传感器校准一直是一个难题。为此．我们研制了CGY-450高压传感器静态校准装置,装置校准压力可以达到450MPa,可以对各种类型压力传感器进行标定。     

高膛压火炮测试用压力传感器静校装置设计

高膛压火炮测试用压力传感器安装在药筒底部测膛底压力。由于压力传感器受到附加应力的作用,使测试数据产生较大的误差。本文介绍一种模拟药筒底部安装条件的静校专用装置,该装置使压力传感器静态校准与实际膛底压力测试的安装条件基本一致,压力传感器与转接器整体进行校准,为研究压电式压力传感器的适用性提供了一套实验装置。     

干式计量炉对不同类型测温传感器校准误差影响的探讨

目前干式计量炉校准测温传感器已经在工业上大量普遍使用,但相关的测量系统仍缺乏整体校准方案,存在不同装置获得的测量结果一致性较差等问题.本文通过校准不同类型测温传感器的实验,探讨了不同装置对校准测温传感器的误差影响大小.经过实验验证,干式计量炉可校准尺寸和孔径匹配的中低温热电偶传感器,且采用辅助措施减少测量误差,也可校准部分热电阻传感器.     

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.     

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.     

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.……     

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.     

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.     

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.……     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.