查询词典 transient time

Due to transient inductances of AC exciter are functions of rotor position and armature winding currents,which are easily influenced by armature current switch on and ferromagnetic material saturation,therefore,analytical method has its limitation to consider current time-variation and ferromagnetic material saturation.

摘 要：由于交流励磁机电枢绕组电流在导通期间的时变性以及铁磁材料饱和特性的影响，瞬态电感是转子位置和电枢绕组电流的多元函数，解析法难以准确计及电流时变性和铁磁材料饱和性的影响。

This thesis is focused on the study of contingency screening method of power system. The main work fulfilled is as follows. 1 Various performance indexes which represent severity degree of contingencies are proposed and analyzed. These indexes are gotten system state before and after contingency clearing obtained by the means of time domain simulation. They can be computed conveniently and immediately and can meet the need of online transient stability analysis.

论文针对电力系统的暂态稳定事故扫描的方法展开研究，主要完成的工作如下： 1提出并分析了能够表征事故严重程度的各种性能指标，这些指标利用时域仿真工具获得事故清除前后的系统状态计算得到，计算方便快捷，可用于事故的快速筛选和排序。

In first, a new short time formula of one dimension heat conduction differential equation, based on the theory of one dimension transient method, is presented for thermophysical property measurement of wood. The result of testing on red pine and larch wood arc satisfied by new method.In succession, the relationship between heat conductivity of wood and moisture, density, porosity, temperature and grain is studied experimentally in the range from 25 to 100℃. The result shows that, the heat conductivity is in direct proportion to density. but in inverse proportion to porosity. The heat conductivity of air-dried wood increased probably linear with the temperature rising. And that heat conductivity along the grain of wood is higher than that cross the grain. The former is 1.8 or 2 times of the latter.

文中研究了25～100℃范围内，气干木材的导热系数与含水率、密度、孔隙率、温度及热流方向的关系，研究表明：木材导热系数与密度成正比关系，与孔隙率成反比关系：对于针叶材，导热系数与密度及孔隙率成线性变化关系，而对于阔叶材其变化关系近似成二次曲线；气干木材的导热系数随着温度的升高近似呈线性增加：热流平行于纹理方向的导热系数大于垂直于纹理方向的导热系数，两者的比值大约在1.8～2之间。

Finally, the techniques of time-serial measurement for transient flow field, three-dimensiqonal tomography, computer image processing and the theories above quantitative calculation studied in the thesis are used to measure the free jet flow field of real rocket, the flow field of bore nozlle, impingment field of exhusted jet, three-dimensional flow field in hypersonic shock tunnel, the flow field of boundary layer transition, explosive and combustion flow field of detonating powder and 3-D temperature field.

最后，利用本文所研究的瞬态流场时间序列定量测试技术，三维C.T技术，计算机图像处理技术和定量计算理论等对真实火箭燃气射流场，膛口流场，燃气射流冲击场，高超音速激波风洞中的三维流场，模型边界层转捩区流场，起爆药爆轰流场和燃烧场、三维温度场等进行测试，取得了一些国际上首创性的成果，并对实现上发现的一些新现象进行理论分析和解释。

Simultaneously, the exports of ionization rate and nonionzed concentration are set up as a powerful tool for studying thoroughly the freeze-out effect. dN〓/dp and dN〓/dn are neglected in the linearized equation system of the iteration methods of Newton and Gummel, due to having lower 15 orders or more than dN〓/dn and dN〓/dp, thus the computing effort is cut down with no effect on precision. A new cut-off technique is adopted to accelerate the convergence speed, about twice reduced for Newton iteration method and six times or so for Gummel iteration method. The approximate formulae of Fermi-Dirac statistics are also put forward with simpler form and higher precision. 3. A term dependent on time is added to the electron and hole current succession equations respectively. It is only this model that conservation of charge in transient analysis and alternating small-signal analysis at low temperature can be kept by. 4. The performance of SE-PISCES is explained by the simulation example of PISCES-2B, diode.

研究了低温半导体器件模拟的数值方法：对载流子浓度进行了新的归一化；编制了不考虑掺杂所引进的内建电场时的电离率计算程序；由于低温杂质电离率随偏压状态而变化，为此编制了每次求解迭代时的电离浓度计算程序，并将其插入到求解迭代程序中；同时，设置了杂质电离率和未电离杂质浓度的出口点，为更深入地研究冻析效应提供了有力工具；在Newton迭代法和Gummel迭代法的线性化方程组中忽略了dN〓/dp、dN〓/dn，是因为它们比dN〓/dn、dN〓/dp低15个数量级以上，这样减小了计算量又不影响模拟精度；对Newton迭代法和Gummel迭代法采取了新的截断技术，提高了收敛速度，Newton法迭代法和两次左右，Gummel法减少六次左右；给出了表达式更简单而精度更高的Fermi-Dirac积分近似计算公式。

A key aspect of plate tectonic theory is that on geologic time scales ocean basins are transient features, opening and closing as plates shift.

板块运动理论的一个关键点就是在地质历史的尺度内，海洋盆地的开合是因为板块转换，具有转换特征。

The transient tune extraction based on NAFF algorithm and damping time calculating based on digital phased-locked amplifier are introduced.

开发了系统配套控制软件和数据处理程序。

Based on this, using high frequency response amplifier, the union of transient data A / D real time collection and computer analysis was realized with advantages of cutting down the intermediate links, simplify trigging and more convenient operation.

在此基础上，利用自制的高频响放大器，实现了霍布金森杆测试中瞬态数据实时A／D采集和计算机分析的一体化，减少了中间环节，使触发更为简单、操作更加方便，并编制了相应的数据分析软件。

A concise summary of development of signal recording techniques in Hopkinson bar experiment is also presented. Based on this, using high frequency response amplifier, the union of transient data A/D real time collection and computer analysis was realized with advantages of cutting down the intermediate links, simplify trigging and more convenient operation.

在此基础上，利用自制的高频响放大器，实现了霍布金森杆测试中瞬态数据实时A／D采集和计算机分析的一体化，减少了中间环节，使触发更为简单、操作更加方便，并编制了相应的数据分析软件。

After years of research, direct method using transient energy function of power system has gotten important development, and has become the main method of time-fiend analysis. In chapter 2, basic theories of TEF method are introduced, and the EEAC method and its application in stability generator tripping control are discussed carefully. A lot of work still need to be done in order to make practical achievement.As a way to actualize this scheme, a new intelligent style under frequency and

多机系统频率动态过程是低频减载方案设计的重要依据，本文在原有线性化扰动模型基础之上，增加了发电机和负荷频率调节效应的影响，并进行了系统仿真研究**同时根据多机模型特点及仿真结果提出了一种基于多机系统的低频减载设计和整定新方案，与传统方案相比，该方案提高了低频减载性能及系统运行方式的适应性

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了