浅析影响薄膜厚薄均匀性的因素

1前言厚薄均匀性是薄膜的一个重要特性,特别是电工薄膜对它的要求更加严格,如果薄膜的均匀性不好,不但生产出来的电容器大小不一,容量不一致,使电容器厂家的成品率下降,而且还会影响制造出来的电容器的某些电性能。众所周知,由于电子产品越来越向着小型化发展,用于制造电容器的电工薄膜必然要向薄的方向发展,这样,电容器厂家就会对薄膜的均匀性提出更高的要求。另外,虽然薄膜的电性能对制造的电容器的电性能起着决定性的作用,但由于国内各生产厂家的生产工艺水平、设备及生产条件都不相上下,生产出来的薄膜的电性能也几乎相差…     

钡系合金在炼钢中的应用研究

介绍了利用含钡合金对钢液进行终脱氧试验，结果表明，含钡合金能脱氧，脱硫，使夹杂物变性，净化钢液，能提高钢的质量。     

A Chinese View on Summary of Condensed Matter Nuclear Science

Investigation on tritium was one of the recommendations in Energy Research Advisory Board (ERAB) report of U. S. Department of Energy (DOE) in November, 1989. Fifteen years evolution of the related research proved that it was an important recommendation. A selective resonant tunneling model is attempted to explain this discovery. Deuterium flux might be a key issue to solve the problem of the reproducibility. A further investigation is suggested based on this model.     

The computer simulation of wear behavior appearing in total hip prosthesis

Computer algorithms are proposed for the estimation of wear appearing in artificial hip joints using finite element analysis based on the modified Archard's wear law, contact features and an analogue wear process. A pin-on-disk plate experiment is reconstructed to assess the efficiency and validity of the algorithms proposed here. Through the successful verification of wear depth and volume loss of the pin-on-disk plate as well as the artificial hip joint, the current algorithms provide significant agreement with experiments, clinical measurements and numerical calculations and are shown to be both valid and feasible. Further investigation into the effect of femoral heads with various sizes suggests that the larger femoral head may induce larger wear volume but gives a smaller wear depth and that wear depth and volume loss are apparently nonlinearly related to the femoral head diameter. It is shown that the current algorithms are useful and helpful in understanding wear behavior for alternative or new designs of artificial hip joints and even for other analogous structures.     

Modeling and computer simulation of ultrasonic/sonic driller/corer (USDC)

Simulation and analytical models for the ultrasonic/sonic drill/corer (USDC) are described in this paper. The USDC was developed as a tool for in-situ rock sampling and analysis in support of the NASA planetary exploration program. The USDC uses a novel drive mechanism, which transfers ultrasonic vibrations of a piezoelectric actuator into larger oscillations of a free-flying mass (free-mass). The free-mass impact on the drill bit creates a stress pulse at the drill tip/rock interface causing fracture in the rock. The main parts of the device (transducer, free-mass, bit, and rock) and the interactions between them were analyzed and numerically modeled to explore the drive mechanism. Each of these interactions is normally described by a time-dependent 2- or 3-D model involving slowly converging solutions, which makes the conventional approach unsuitable for USDC optimization studies. A simplified integrated model using tabulated data was developed to simulate the operation of the USDC on desktop PC and successfully predicted the characteristics of the device under a variety of conditions. The simulated results of the model and the experimental data used to verify the model are presented.     

代理键技术及其在软件复用中的应用

在数据库的设计中,当不同实体需要用到同样的方法或流程进行操作处理时,由于实体间结构上的差异,往往难以复用相同的模块,这也使得设计极其困难。针对这一问题,提出了用代理键技术,通过消除主码语义的方法来屏蔽不同实体即关系数据库中的表之间结构上的差异,从而可以为软件复用提供便利。     

Study on Pollution Flashover Performance of Short Samples of Composite Insulators Intended for /spl plusmn/800 kV UHV DC

Based on the artificial pollution tests, the effects of pollution and high altitude on the flashover performance of short samples of five kinds of UHV/EHV dc composite long rod insulators are analyzed. The exponent characterizing the influence of salt deposit density on the flashover voltage is related with the profile and the material of the insulator shed. The values of the samples' exponents vary between 0.24 and 0.30, which are smaller than those of porcelain or glass cap-and-pin insulators, namely, the influence of the pollution on the composite long rod insulators is less, relatively. Thus, the composite insulators have certain advantages in severe pollution regions. The best ratio of the leakage distance to the arcing distance is about 3.35. The exponent characterizing the influence of air pressure on the flashover voltage is related with the profile and the material of the insulator shed and the pollution severity, the values of the samples' exponents vary between 0.6 and 0.8, which are larger than those of porcelain or glass cap-and-pin insulators. Therefore, the dc composite insulator used in high altitude regions should have enough arcing distance. Based on the test results, if insulator sample Type E is selected for the plusmn800 kV UHV dc transmission lines, the basic arcing distance should be no less than 8.16 m and the basic leakage distance no less than 30.2 m.     

Experimental study on the ion migration of rod samples for high voltage DC porcelain support insulators

The ion migration testing used for DC porcelain support insulators was carried out in this paper. Ten rod samples for DC porcelain support insulators were subjected to a long-term ion migration testing in our laboratory in accordance with the reported procedure of IEC. The changes of Na⁺ distribution along with the samples under the long-term testing were analyzed, compared to that of the untested samples. The mechanical performance of the tested samples was verified by using bending breakdown testing. The research findings indicate that the ion migration testing designed for support insulators does not cause Na⁺ ion apparent migration in the samples and does not influence the mechanical performance of the tested samples     

取水泵房加固处理措施探析

由于下游新建乐昌峡水利枢纽工程,导致水位上升,坪石发电厂江边取水泵房结构不能满足规范要求,需对该泵房结构进行加固处理。实践证明,采用改变结构传力路径加固法和加大截面加固法相结合的方式在技术上是可行的,具有缩短工期、节约投资的优点。此方法的成功应用,对同类型加固改造工程具有一定的参考价值。