Ac - dc transfer instruments will be calibrated by comparison with the laboratory standards , which cover the range 0 . 25 v to 1000 v and 40 hz to 1 mhz 交直流转换器的校正是透过与本所的标准(由0 . 25v至1000v及40hz至1mhz )对比进行。
The digital tube four bearing indications , report to the police the volume to be possible to move the a . c . - d . c , the acousto - optics also reports to the police outlook size : 1712 . 54cm 数码管四方位显示，报警音量可调交直流两用，声光同时报警外型尺寸：
We also investigate the dynamics of electrons and the quasi - energy spectrum of the system with strong interband coupling in real space , and obtain the phase - diagram in the parameter space 得到在纯交流场和交直流场驱动下，存在强带间耦合时电子的动力学性质和系统的准能谱。
The performance of its basic controller decides the operation condition of hvdc system . for improving the system stability in ac / dc system , the additional controller is very important 直流输电系统能否正常运行与其基本控制器的性能息息相关，附加控制器又是提高交直流互联系统运行稳定性的重要保证。
With the gradual implementation of power transmission from the west to the east and nation - wide power grid interconnection , a national complicated ac / dc power grid will be formed in the future 随着西电东送、全国联网工程的逐步实施,我国将形成复杂的交直流联合网架结构,而解决此类问题也变得越来越重要。
So it is more and more important to study such problems . the thesis focuses on the coordinated control strategies in ac / dc systems , some control methods are presented and the effectiveness is analyzed by numerical simulation 论文着重对交直流混合系统的协调控制策略进行了较为深入的研究,提出了一些控制方法,并通过数字仿真进行了分析。
Based on differential geometric theory , a novel nonlinear modulation strategy for multi - iii infeed hvdc systems to enhance the transient stability of ac system in the presence of large disturbances is presented in this paper 针对大扰动情形，提出了一种用于改善多机交直流混合电力系统(有多条直流线路落点于其中)暂态稳定性的非线性调制策略。
Manufacturer of precision instruments and controls including barometers , density monitors and level control for use in applications in chemical , petrochemical , food , medical , pharmaceutical , water and wastewater treatment , utility industries -销售非接触红外测温仪环境测试仪音量计噪音计照度计温湿度计一氧化碳测试仪电力基础仪表数字万用表交直流钳形表。
A six - order dynamic model is established for a single - machine infinite bus system with parallel ac / dc transmission lines , in which the dynamic regulating process of the generator and hvdc are considered comprehensively , and the excitation controller is neglected 基于单机无穷大交直流并联系统,忽略励磁控制器,综合考虑发电机和直流输电系统的动态调节过程,建立六阶动态模型。
Specification for fixed capacitors of assessed quality : generic data and methods of test - polycarbonate dielectric capacitors and polyethylene terephthalate dielectric capacitors for d . c . use and polypropylene dielectric capacitors for d . c . and a . c . use 经质量评估的固定式电容器规范.一般数据和试验方法.第6节:直流用聚碳酸酯介质电容器和聚乙烯对苯二甲酸酯介质电容器以及交直流用聚丙烯介质电容器
