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排序方式: 共有303条查询结果,搜索用时 15 毫秒
1.
This paper mainly focuses on the influence of three kinds of media: air, air-10%PA (Nylon) and air-10% POM (polyoxymethylene) on low-voltage circuit breaker arcs. A threedimensional (3-D) model of arc motioa under the effect of external magnetic field is built based on magnetohydrodynamics (MHD) equations. By adopting the commercial computational fluid dynamics (CFD) package based on the control-volume method, the above MHD equations are solved. For the media of air-10%PA and air-10%POM, the distributions of stationary temperature and electrical potential and the transient motion processes are compared with those of air arc. The research shows that both air-10%PA and air -10% POM can cool the arc plasma and the former is more effective. Both of them can increase the stationary voltage as well. Moreover, the presence of the two mixtures can accelerate the arc motion toward the quenching area and ensures the arc quenched in time. 相似文献
2.
介绍了一种基于IRT/CTT混合模型的上机测试软件实现方法.详细介绍了基于IRT模型的测试算法实现过程.对基于CTT模型实现的上机测试软件中测试结果打包和传输问题给出了实现方法. 相似文献
3.
王军华 《中国材料科技与设备》2006,3(1):97-97,105
研究了射频溅射法制备的金属/半导体类型颗粒膜的光学特性。通过样品透射谱分析,发现金属Fe的掺杂使半导体In2O3的带间跌迁由直接跃迁变为间接跃迁;随Fe所占体积份数的增加,局域态尾变宽,带隙变窄。这是由于掺入Fe颗粒后。母体材料与金属颗粒的界面处表面态增多,以及母体材料的非晶化引起的。 相似文献
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Simulation Research of Magnetic Constriction Effect and Controlling by Axial Magnetic Field of Vacuum Arc 总被引:2,自引:0,他引:2
Based on magnetohydrodynamic (MHD) model of vacuum arc, the computer simulation of vacuum arc was carried out in this paper. In the MHD model, mass conservation equation, momentum conservation equations, energy conservation equations, generalized ohm‘s law and Maxwell equation were considered. MHD equations were calculated by numerical method, and the distribution of vacuum arc plasma parameters and current density were obtained. Simulation results showed that the magnetic constriction effect of vacuum arc is primarily caused by the Hall effect. In addition, the inhibition of axial magnetic field (AMF) on constriction of vacuum arc was calculated and analyzed. 相似文献
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Numerical Study on Arc Plasma Behavior During Arc Commutation Process in Direct Current Circuit Breaker 总被引:1,自引:0,他引:1
This paper focuses on the numerical investigation of arc plasma behavior during arc commutation process in a medium-voltage direct current circuit breaker(DCCB) contact system.A three-dimensional magneto-hydrodynamic(MHD) model of air arc plasma in the contact system of a DCCB is developed,based on commercial software FLUENT.Coupled electromagnetic and gas dynamic interactions are considered as usual,and a thin layer of nonlinear electrical resistance elements is used to represent the voltage drop of plasma sheath and the formation of new arc root.The distributions of pressure,temperature,gas flow and current density of arc plasma in arc region are calculated.The simulation results indicate that the pressure distribution related to the contact system has a strong effect on the arc commutation process,arising from the change of electrical conductivity in the arc root region.In DCCB contact system,the pressure of arc root region will be concentrated and higher if the space above the moving contact is enclosed,which is not good for arc root commutation.However,when the region is opened,the pressure distribution would be lower and more evenly,which is favorable for the arc root commutation. 相似文献
10.
职工是企业的主人,是物质财富的创造者。他们工作的积极性是企业的发展源泉和动力。如何最大限度地调动职工的生产热情发挥职工的潜能,促进他们多为企业发展献计献策,是管理者要考虑的一个重要问题,本文通过员工沉默来阐述人力资源管理对员工的重要性。 相似文献