低温烧结SrTiO3晶界垫垒高度的研究

本文利用双Ｓｃｈｏｔｔｋｙ势垒模型依据ＳｒＴｉＯ３晶界层电容器材料的Ｒ－Ｔ特性和室温下的Ｉ－Ｖ特性获得了晶界垫垒高度随温度变化的关系，结果表明，势垒高度随温度的升高而增加，定结果与用各不同温度下的Ｉ－Ｖ特性拟合所得到的势垒值基本相符。     

（Sr,Ca）TiO3系复合功能陶瓷的涂覆离子热扩散

采用碱金属离子液相涂覆热扩散方法，研究了涂覆离子，热扩散条件等对（Ｓｒ，Ｃａ）ＴｉＯ３系陶瓷电性能的影响；用电子探针（ＥＰＡ）分析了涂覆离子在晶粒边界的浓度分布；根据中间夹层的双Ｓｃｈｏｔｔｋｙ势垒模型，对测量出的Ｃ－Ｖ特性进行了计算和拟合，求得各种热扩散条件下的晶界势垒高度，讨论了扩散条件，电性能，晶界势垒之间的内在联系。     

(Sr,Ca)TiO_3系复合功能陶瓷的涂覆离子热扩散

采用碱金属离子液相涂覆热扩散方法,研究了涂覆离子、热扩散条件等对(Sr,Ca)TiO_3系陶瓷电性能的影响;用电子探针(EPA)分析了涂覆离子在晶粒边界的浓度分布;根据中间夹层的双 Schottky势垒模型,对测量出的C—V特性进行了计算和拟合,求得各种热扩散条件下的晶界势垒高度。讨论了扩散条件、电性能、晶界势垒之间的内在联系。     

热分解氧化反应对TiO2电容压敏电阻器性能的影响

研究了具有热分解氧化反应的ＣｕＯ、ＭｎＯ_２等的一类氧化物对ＴｉＯ_２压敏电阻器性能的影响,采用Ｃ—Ｖ分析、Ｉ—Ｖ测量和介电测量等实验手段,分析了它们的作用机理．结果发现,在晶界处发生的热分解氧化反应能增加界面态密度,提高晶界势垒高度,从而改善ＴｉＯ_２电容压敏电阻器的非线性性能．     

晶界势垒对晶界层电容器性能的影响

本文从晶界势垒的角度研究了中间夹层的 Schottky 晶界势垒对晶界层电容的介电常数、工作电压等电性能的影响。对在空气中烧成和在还原气氛中烧成的 SrTiO_3晶界层电容器电性能的较大差别给予了一些解释。     

晶界层电容器晶界势垒的研究

以中间夹层的 Schottky 势垒作为晶界层电容器晶界势垒,从理论上分析、推导了电流电压关系和电容电压关系。利用这些关系式对实验测试数据进行了计算机模拟,并用实验结果和计算机模拟结果检验了该晶界势垒模型的合理性。在此基础上揭示出晶界势垒对晶界层电容器电性能所起的关健作用。     

锆英石陶瓷的晶界特性对其高温力学性能的影响

本文通过扫描电镜（ＳＥＭ）观察断口形貌和高分辨电镜（ＨＲＥＭ）观察晶界形貌，研究了锆英石陶瓷的晶界特性对其高温力学性能的影响．结果表明：锆英石陶瓷中两晶粒间的晶界上未观察到玻璃相存在，而在三晶界交汇处则发现少量玻璃相，引起锆英石陶瓷在高温下力学性能下降．与此同时，断裂方式也从常温下的穿晶断裂转变成为高温条件下的沿晶断裂．     

ZnO/P-Si接触及其温度特性

用射频磁控溅射在硅衬底上淀积ZnO薄膜,随后进行I-V-T测量.实验结果显示硅基氧化锌接触具有异质结特性,异质结的电流输运机制为热发射和电流隧穿.用I-V-T测量的结果拟合计算了势垒高度和理想因子,结果发现ZnO/P-Si势垒高度随温度降低而减小理想因子则升高.异质结的这种反常的随温度变化的关系可以用肖特基势垒不均匀性理论解释.样品经Air～800℃热退火后势垒高度与未退火相比上升,说明热退火改善了氧化锌薄膜的结晶质量,减少了界面态影响.     

温度对传感器气敏材料电阻的影响研究

从传感器气敏材料的电阻微小变化中可得到许多有用的信息,其电阻对材料的温度非常敏感.实验中所用传感器的气敏材料是在配有加热器的铝基底上沉积SnO2薄膜,通过控制加热器上的电压来改变气敏材料的温度(温度变化范围为25～400℃),研究了温度对材料电阻的影响.通过分析电阻随温度的变化,基于晶界势垒控制模型得到了关于电阻随温度变化的新经验方程,并将此方程的计算结果与实验结果进行了比较.结果表明,此方程可很好地描述某些型号的传感器电阻对温度的依赖行为.     

5Cr21Mn9Ni4N钢高温加热后的晶界沉淀

观察研究了５Ｃｒ２１Ｍｎ９Ｎｉ４Ｎ钢在１２１０－１２５０℃加热后晶界沉淀的数量和尺寸随温度的变化，晶界沉淀的类型及沉淀中的铬含量随冷却速度的变化。分析讨论了试样的化学成分，特别是Ｓｉ含量对晶界沉淀的类型，数量和断口特征及晶粒长大倾向的影响。     

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.