查询词典 DC

Variable magnetic pole DC motor can resolve the problem of commutator existing in the traditional DC motor.

变磁极性直流电机解决了传统直流电机的换向器问题。

The reasons of cross talk in print circuit board were analyzed and improving ways were given.

驱动电路的供电采用可级联的DC／DC模块搭建。

The circuit topology of the differential Forward DC-DC converter mode inverter with high frequency link was proposed. Circuit topology, transient voltage control strategy, steady principle characteristic and design criteria for the key circuit parameters were deeply investigated.

提出差动正激直流变换器型高频环节逆变器电路拓扑，并对该变换器的电路拓扑、瞬时电压控制策略、稳态原理特性、关键电路参数设计准则等进行了深入地分析研究。

According to the demand of high magnetic field power supply, reference is increased with a set ramp rate and stops at a set stable value, so reference system is composed of digital setting and digit to analog converting circuit. But the stability of reference is mostly guaranteed by the performance of D/A circuit, so D/A circuit is particularly studied in reference system. The scheme of D/A circuit, the selection of DAC and its voltage reference, hardware anti-jamming design and PCB design are discussed in detail, and software of remote control and PLC are discussed in brief. Zero-flux DC current transformer well satisfies the demands of the high stability of Load current detection unit, so the principle of zero-flux DC current transformer is analyzed; in the mean time a project which detects the long term stability is designed. During 8 hours, analog signal which is detected with high precision digit multimeter is recorded in computer at 1HZ frequency by GPIB communication. The drift error source and related parameters are explained in the compare-amplify part. Detailed subtraction circuit is designed; also amplifier chip and periphery components are selected and verified according to the theory of error analysis.

根据强磁场电源的需求，参考源应按照软件设定的斜率逐渐上升到设定稳态值，则参考源系统应由数字给定和数模转换电路两大部分组成，而参考源的稳定度主要依靠完成数模转换功能的模拟电路的性能来保证，因此本文对参考源系统的研究以数模转换电路为重点，分别从电路方案的确定、数模转换芯片及其基准电压源的选取和验证、电路板硬件抗干扰和PCB设计几方面进行了论述，然后对数字给定部分的远控组态和PLC程序设计作了简要介绍；采用零磁通原理的直流电流转换器很好地满足了对负载电流检测单元高稳定度的需求，本文详细分析了零磁通检测的原理，并在选定此种类型电流转换器的基础上设计了一套检测长期稳定度的方案，8小时内以1秒为采样周期，通过计算机Labview程序和高精度数字电压表的GPIB通讯，将被高精度数字电压表数字化后的模拟信号采样值连续记录至计算机中；比较放大环节简要阐述了漂移产生的原因和相关参数指标，确定了具体的减法电路形式，并根据误差分析理论对运算放大器和外围元器件进行了选取和验证。

A DC motor driver with constant frequency PWM is developed based on PIC, and the running performance of the DC motor is improved greatly.

另外使用PIC器件完成了单芯片集成式运行电路的设计，实现了直流电机的正常驱动，简化了控制逻辑系统。

Duality principle ; DC DC converter ; directed topological graph

对偶原理；直流；直流变换器；有向拓扑图。

The Non-perfect Elastic Collision DC model in half space is presented, considering the influence of participating soil mass and the interaction of tamper and ground during DC. Series solutions of displacement, velocity, acceleration and impact stress are obtained.

通过与边界元法、Laplace—Hankel联合反变换法的计算结果，以及山西某湿陷性黄土地基和南京某填土地基工程中的实测数据的验证和对比表明，该模型是符合实际的，它可用于分析强夯规律，计算冲击应力，解释强夯加固机理和工程中的现象，便于工程应用，而且比其他方法简单易行。

It is extensively used for different occasions that require DC power supply, including electrolytic chemistry, transmission, traction, electrostatic precipitation, electroplating and DC transmission etc.

整流变压器是指把电力网的三相正弦交流电压变换为所需要的交流整流电源的电压和相数的电源变压器，它广泛应用于点解化学、传动、牵引、静电除尘、电镀、直流输电等需要提供直流电源的场合。

This paper discusses a method, which can be used to approximately calculate the equivalent resistance and to approximately calculate the efficiency of different topologies. It could benefit a lot in designing DC-DC converters.

本文提出了一种近似计算等效电阻的方法，其原理是将变换器中各元件的损耗之和等效为输出电阻的损耗，可以简便计算变换器的效率，有助于选择合适的电路。

The trace element contents of Eupatorium lindleyanum DC in different parts in different harvest periods and their correlation to their pharmacological activities were analyzed by determining the pH value and trace element contents of Eupatorium lindleyanum DC in planting field.

方法］通过则定了野马追种植大田内土壤的pH值及其微量元素的含量，分析了野马追不同采收期各部位的微量元素含量以及其与药理活性间的相关性。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。