大型水轮发电机组励磁变压器参数及绝缘方式的选择--由三峡机组励磁系统投运引起的思考

结合三峡机组励磁系统的调试及投运经验,对大型水电机组静止自励系统选型中存在的一些关键性技术课题进行分析与论证,期望得出的结论有助于在大型水轮发电机组励磁系统参数选择和在提高机组运行安全、可靠性方面提供有益的借鉴。文中提出的励磁系统设计新理念仅代表个人的观点。     

POWER OPTIMIZATION OF FINITE STATE MACHINE BASED ON GENETIC ALGORITHM

Using state assignment to minimize power dissipation and area for finite state machines is computationally hard.Most of published results show that the reduction of switching activity often trades with area penalty.In this paper,a new approach is proposed.Experimental results show a significant reduction of switching activity without area penalty compared with previous publications.     

火电厂实施废水零排放的可行性探讨

对合肥发电厂的用排水现状进行了介绍，并提出了实施废水零排放的可行性方案。     

Studies on Three—electrode Semiconductor Lasers

Using the ray trace method,three-section semiconductor lasers are studied .An analytic expression of output power for the three-section semiconductor lasers is derived for the first time.Frome this expression,threshold condition is also obtained.     

S频段大功率振荡用砷化镓场效应晶体管的微波性能

对WC76型S频段大功率振荡用砷化镓场效应晶体管的微波性能作了介绍。文中给出了测试振荡器的设计。测试结果表明,WC76型振荡管在s频段的微波性能良好,振荡频率在3GHz左右时,输出功率可达3.5w,直流—射频转换效率可达44％,而且在2～4GHz的整个S频段均能满意地工作。     

Equilibrium solubility of CO2 in rubbery EVA over a wide pressure range: effects of carbonyl group content and crystallinity

The equilibrium CO₂ sorption isotherms and isobars for rubbery EVA containing various amounts of vinyl acetate (VA) over a wide pressure range 10-340 atm and 25-52 °C were investigated. The normalized CO₂ sorption concentration (in cm³ (STP) CO₂/mole VA) isotherms of these polymers as a function of pressure consisted of two distinct regions turning at near P_c. The normalized sorption isotherms in these two distinct regions could be fairly described by two respective power laws: C=K_aP^n_a for above P_c and C=k_bP^n_b for below P_c. The normalized CO₂ sorption isotherms were found to be about the same for four EVA samples having different VA contents for below P_c, suggesting that the sorption process at below P_c may be mainly driven by the presence of carbonyl groups. At above P_c, the degree of crystallinity of the polymer appeared to be a major factor to affect the sorption process, with the higher the degree of crystallinity, the lower the normalized CO₂ sorption concentration in the polymer. The sorption isobars of the polymer as a function of temperature were governed by the interplay of density, viscosity, and diffusivity of CO₂ depending on the pressure studied.     

权力及正确权力观的标志

权力是统治阶级的权力,是统治阶级统治力量和意志的体现,是为统治阶级的利益服务的。在社会主义社会,权力是人民的权力。保证权力的人民性必须有相应的权力运行机制,在根本上则取决于领导干部树立正确的权利观,坚持为民执政、为民勤政、为民廉政。     

红外加热节能技术的现状与发展前景

本文综述了国内外节能的现状与发展趋势,论述了远红外电加热领域的发展前景,强调了加强基础理论研究的重要性,介绍了我国红外加热应用的领域和国外新开发的红外产品。     

Silicon power MOSFET at low temperatures: A two-dimensional computer simulation study

Understanding how the structure of the unit-cell affects the cryogenic performance of a Si power Metal Oxide Semiconductor Field Effect Transistor (MOSFET) is an important step toward optimizing of the device for cryogenic operations. In this paper, numerical simulations of the Si power Double Diffused MOSFET’ (DMOS) are performed at room temperature and cryogenic temperatures. Physically based models for temperature dependent silicon properties are employed in the simulations. The performances of power DMOS’ with various unit-cell structures are compared at both room temperature and low temperatures. The effect of the cell structure on the on-resistance and breakdown voltage of the device are analyzed. The simulation results suggest that the device optimized for room temperature operation can be further optimized at cryogenic temperatures.     

多功能半导体激光医疗仪电源的研制

根据“多功能半导体激光医疗仪”整机的要求,采用同一电源对667nm和808nm半导体激光器实施供电。为避免电源在开、关机时对半导体激光管产生浪涌冲击,电源在设计中采用了适当的逻辑功能。并可保证对667nm激光器供电时,即使打开808nm激光器供电开关,也不对808nm半导体激光器供电,反之亦然。电源设有手动、计算机两种控制方法,及恒定功率、电流两种工作方式。