航天器镁合金防腐-热控一体化涂层性能研究

以航天器镁合金防腐-热控一体化涂层为研究对象,分别通过盐雾试验、湿热试验和空间环境辐照试验(包括真空-紫外辐照、真空-质子辐照和真空-电子辐照)研究了涂层防腐性能和空间环境稳定性。结果表明以氟化羟基树脂和六亚甲基二异氰酸酯三聚体交联反应制得的脂肪族聚氨酯为粘结剂,制备的热控涂层具有耐湿热504h,耐盐雾腐蚀1008h的防腐性能,盐雾环境对α_S有一定影响,Δα_S为0.02;真空-紫外辐照、真空-质子辐照对α_S有一定影响,Δα_S分别为0.03和0.04;真空-紫外辐照、真空-质子辐照、真空-电子辐照均对热控涂层ε_H影响不明显,热控涂层高发射率热控特性在空间环境中稳定性好。     

钙钛矿型锰氧化物在热控薄膜材料方面的应用

钙钛矿型锰氧化物材料具有热致相变特性,其半球发射率随温度不同而有较大的变化,利用这种相变特性可以制备航天器用智能型热控器件,这种器件具有重量小、不耗电、可靠性高等优点,成为未来热控涂层的重要选择.本文对钙钛矿型锰氧化物材料的特性及机理作一个简单介绍.     

高温扩散法制备铁铝金属间化合物涂层

针对金属间化合物在工业中作为高温结构材料使用存在脆性的问题，将金属间化合物以涂层的方式应用。以Fe-Al系为研究体系，以高温扩散制备的方法获得了良好的Fe-Al金属间化合物涂层，实验结果表明，在合适的工艺参数下，所得到的涂层具有单一性，致密性且与基体结合良好，该涂层具有良好的高温耐磨，耐蚀，耐氧化等特性。     

空间辐射环境作用下热控涂层光学特性退化仿真方法研究

对于长寿命卫星而言,需要评估热控涂层在空间使用期间的性能退化状况。针对星用典型热控涂层,建立了辐照下光学特性退化模型并提出了光学特性预示软件编制方案,为空间环境作用下材料光学特性退化的计算模拟奠定了基础。     

涂料型La1-xSrxMnO3智能热控涂层的研究

以固相反应法制备了高纯度La0.8Sr0.2MnO3粉体,并以其为基料,磷酸二氢铝为粘结剂,采用涂覆工艺在铝基片上制备了涂料型La0.8Sr0.2MnO3热控涂层.采用XRD、EDS对La0.8Sr0.2MnO3粉体的成分进行了表征,用稳态卡计法测量了涂层在100~100℃温度区间内热辐射率随温度的变化,并测量了涂层的太阳吸收比.研究结果表明:粉体合成过程中,经过1200℃三次热处理制备的La0.8Sr0.2MnO3粉体纯度高,合成的粉体具有均匀的微米级粒径尺寸.通过适当调整浆料中La0.8Sr0.2MnO3粉体所占质量百分比,获得辐射率变化范围大于0.3的热控涂层,该性能与采用烧结工艺制备的La0.8Sr0.2MnO3陶瓷片材料在变温条件下的辐射率变化范围接近.该涂层在航天器热控技术中具有潜在的应用前景.     

强电磁场条件下热控涂层的分解机理及其对电性能的影响

热控涂层是航天器热控系统中重要的功能性涂层材料.针对热控白漆ACR-1在真空强电磁场条件下的耐温性、分解特性、电性能(介电常数、损耗角正切)以及电性能的退化情况进行了研究.结果 表明,热控涂层进入热分解阶段后,其表观颜色逐渐变深,涂层结构由致密转化为多孔状,损耗角正切值随着降解程度的提高而逐渐增大,电磁场在热控涂层中的能量损耗也相应增大,从而导致热控涂层的热平衡温度提升.当涂层材料分解殆尽,完全碳化,其损耗角正切值急剧增大,电磁波损耗也急剧增大,设备电性能指标下降明显,偏离了设计要求.     

基于单分子层模型的ZnO热控涂层电子辐照光学性能退化研究

在分析电子辐照对ZnO类热控涂层光学性能退化机理的基础上,提出了单分子层电子色心产生模型,推导了"色心浓度"表达式及材料光学性能退化随辐照剂量的变化关系。用该理论对100keV电子辐照下S781白漆太阳吸收比变化Δαs的实验数据的拟合结果表明,单分子层模型能够很好地预测ZnO类热控涂层在电子辐照环境下光学特性退化趋势。该理论可扩展应用于其它热控材料在空间不同辐射环境下光学性能退化趋势的预测。     

低as无机热控涂层及其空间防护作用研究

介绍了两种无机热控涂层的组成工艺及性能，并讨论了影响涂层性能的因素。用LAMBDA-9分光光度计和扫描电镜(SEM)对在模拟原子氧(AO)环境中，无机热控涂层太阳光吸收率(as)的变化和它们的防护作用进行了表征研究。结果表明，该涂层具有良好的空间稳定性和较低的as，能有效抵御AO的侵蚀，对空间材料可起到满意的防护效果。尤其是10-3涂层的as最低，性能最稳定。     

AlYSi涂层组织结构及抗燃气热腐蚀性能

采用真空电弧离子镀技术在K465镍基高温合金基材上制备了AlYSi沉积-扩散型涂层。研究了真空退火处理前后涂层的组织结构,以及涂层在900℃下的燃气热腐蚀行为。结果表明,经真空退火处理后的AlYSi涂层主要由β-NiAl相组成,与基体结合良好;K465合金在热腐蚀过程中表面产生了大量的腐蚀剥落;AlYSi涂层在热腐蚀过程中表面形成了Al2O3保护膜,显著提高了合金的抗燃气热腐蚀性能。     

低αs无机热控涂层及其空间防护作用研究

介绍了两种无机热控涂层的组成工艺及性能,并讨论了影响涂层性能的因素.用LAMBDA-9分光光度计和扫描电镜(SEM)对在模拟原子氧(AO)环境中,无机热控涂层太阳光吸收率(αs)的变化和它们的防护作用进行了表征研究.结果表明,该涂层具有良好的空间稳定性和较低的αs,能有效抵御AO的侵蚀,对空间材料可起到满意的防护效果.尤其是10-3涂层的αs最低,性能最稳定.     

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.