适合航天电子系统应用的DC－DC变换器

讨论了航天ＤＣ－ＤＣ混合集成电路的拓朴结构。通过对几种电路的性能比较，提出了适合航天应用的ＤＣ－ＤＣ变换器的最佳拓朴结构。论述了ＰＷＭ－ＬＩＮ变换器的控制方法，该方法对于确保二次稳压ＤＣ－ＤＣ变换器较高的效率具有重要意义，亦可大大提高混合集成电路的成品率。     

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。     

最优化分析使网络电路输出功率最大

用最速上升法分析具有多负载的有源线性网络电路,使其输出功率最大,它可以为电子器件端口的合理布置提供最优数据。     

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。     

多点驱动的上运带式输送机功率平衡的研究

介绍了液粘装置的转矩特性方程,分析了采用液体粘性软起动装置调节功率平衡的原理,并说明了如何从电气上实现该功能。最后通过应用实例表明,应用液粘装置调节功率平衡达到了理想的效果。     

沙河抽水蓄能电站生产实时系统设计及实施

为了使水电站所有生产、管理人员和领导决策层在任何时间及地点均能及时掌握整个电厂机组的实时运行状态,沙河抽水蓄能电站引用了一套生产实时系统。该系统将生产运行的一些实时数据通过内部局域网发布,具有安全、易用、实时、先进、开放、标准化、易管理等特点,可为电厂的现代化管理、为提高企业经济效益提供第一手技术资料。     

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.