查询词典 impedance

First , measure the open circuit voltage and short circuit current to get the current system impedance, then force the apparent load impedance to match it to make the solar system working on maximum power point.

而如何有效的取得太阳电池的开路电压及短路电流，以便正确计算出太阳电池的内部阻抗则为本论文研究重点。

We use the single chip PIC18F452, as the center control circuit, and through the measurement of open circuit voltage and short circuit current to get the current system impedance, then force the apparent load impedance to match it to make the solar system working on maximum power point.

本论文使用阻抗匹配法的最大功率点追踪技术，将能有效预知下次的最大功率点位置，使系统维持工作在最大功率点上，达到最大功率输出的目的。

D seismic and logging data of the first mining area in the Xinyi coal mine are dealt with impedance inversion to predict aquosity and watertightness of the top Ordovician limestone and the possible water-rich areas in the aquifer are determined by the impedance values.

本文根据新驿煤矿首采区的三维地震和测井资料，利用波阻抗反演技术预测该区奥陶系灰岩顶部的含隔水性，并依据波阻抗值的大小圈定含水层中的可能富水区。

Our process capability: Plates: FR4, High TG FR4, high CTI FR4, high frequency materials, halogen-free materials, aluminum and other low-rise Materials :2-20 layer of finished copper thickness :0.5-5 OZ finished thickness: 0.2 -6.0mm Minimum line width: 3mil Minimum line spacing: 3mil smallest shape tolerances:+/-0.1mm minimum finished diameter: 0.1mm maximum thickness aperture ratio: 12:1 wide minimum solder bridge: 4mil characters minimum line width: 5mil Minimum height of characters: 30mil Solder Mask Color: Green, black, blue, white, yellow, purple characters such as color: white, yellow, black and other surface processes: spray tin, lead-free HASL, Electroless gold plating Shuijin, OSP, chemical Shen tin, silver and other chemicals Shen Process: Goldfinger, blue gum, Blind-via/Buried-via, characteristic impedance control, rigid-flexible combination of reliability testing such as: Open / Short testing, impedance testing, solderability testing, thermal shock testing, metallographic analysis of micro-slice curvature Isoptera: 0.7% flame retardant Level: 94V-0

我们公司的制程能力：板材：FR4、高TG FR4、高CTI FR4、高频材料、无卤素材料、铝基材料等层数：2-20层成品铜厚：0.5-5 OZ成品板厚：0.2-6.0mm最小线宽：3mil最小线间距：3mil最小外形公差：+/-0.1mm最小成品孔径：0.1mm最大板厚孔径比：12：1最小阻焊桥宽：4mil最小字符线宽：5mil最小字符高度：30mil阻焊颜色：绿色、黑色、蓝色、白色、黄色、紫色等字符颜色：白色、黄色、黑色等表面工艺：喷锡，无铅喷锡、化学沉金、电镀水金、OSP、化学沉锡、化学沉银等其它工艺：金手指、蓝胶、盲埋孔、特性阻抗控制、刚柔结合等可靠性测试：开/短路测试、阻抗测试、可焊性测试、热冲击测试、金相微切片分析等翅曲度：≤0.7%阻燃等级：94V-0

The design for impedance converting circuit of input current,transistor amplifying circuit and converting circuit of output current is presented.The telegrapher equations are adopted to determine the impedance of transmission-line transformer,which is used to convert circuit impedance between signal source and transistor.

讨论了放大器输入回路阻抗变换电路、晶体管放大电路以及输出回路阻抗变换电路的设计思想，运用电报方程从理论上推导出用于信号源和晶体管之间阻抗变换的传输线变压器输入输出阻抗计算公式，由此设计出模拟信号处理电路中非常重要的AB类高功率放大器。

These antennas can cover GSM900/DCS/PCS/UMTS operation. In the chapter 2, the antenna is designed based on the concept of monopole antenna. Furthermore, the antenna structure have two radiant paths and coupled each other at tail end to do impedance matching. In addition, to raise distance between radiation plane and ground will avoid capacitative effect effectually. In the chapter 3, the antenna is designed based on the concept of planar inverted-F antenna. Furthermore, that the antenna structure have two radiant paths and coupled each other at tail end to do impedance matching is similar to chapter 2. But there is a difference in them. We can choose the short position to change input impedance at this structure. In the chapter 4, the antenna is designed based on the concept of planar inverted-F antenna which takes coupled-fed. It will produce the first mode and high-order mode near the frequency, 900MHz. The feature of this type is to reduce the volume effectually. This antenna can not only cover GSM900/DCS/PCS/UMTS operation but maintain good radiation efficiency. Finally, we will compare three antennas, and develop procedure with industrial view, and propose the prospect of the GSM/GPRS antenna in PND, as a conclusion.

在第二章中，我们使用单极天线设计概念，使用双路径架构并於末端耦合来对天线阻抗做匹配，产生涵盖GSM900/DCS/PCS/UMTS四频操作频带，并提高与接地面的辐射高度，以避免电容效应，使天线具有良好的辐射特性；在第三章中，使用倒F形天线设计概念，使用双路径架构於末端耦合，并於辐射臂上采取适当接地点电感效应作输入阻抗匹配，达成涵盖GSM900/DCS/PCS/UMTS系统的四个操作频带；在第四章中，采用倒F形架构并使用耦合馈入方式，使得长辐射金属臂在低频900 MHz附近产生共振，产生低频基频模态及高阶模态，以达成宽频及频宽涵盖GSM900/DCS/PCS/UMTS频带操作，并有效缩减使用体积；最后，分别比较此三种架构的优缺点，再加以业界角度来思考，研发产品天线的流程及思考方向，以及天线应用於可携式导航装置中未来的展望作为本论文的总结。

Geophysical characteristics of Ordovician carbonate rock were studied using drilling data. Impedance is affected mostly by material properties and reservoirs types, to a negligibly extent by lithology and flow. Compact layers and minor\|fracture reservoirs of Ordovician carbonate rock have characteristics of high density, high velocity and high impedance, and the prediction of minor fractures reservoir is difficult by the general seismic ways. Big fractures and fractured\|vuggy and vuggy and cavity reservoirs of Ordovician carbonate rock have characteristics of minor density and low velocity and low impedance in central Tarim basin, which obviously different from the surrounding rock and produce obvious characteristics in seismic data, so reservoirs can be predicted by applying general seismic data.

根据已钻井资料，对塔中地区上奥陶统良里塔格组岩石地球物理特征进行了研究，结果表明：物性、储层类型对波阻抗影响最大，岩性、流体对波阻抗影响较小；奥陶系碳酸盐岩致密层和小裂缝型储层具有密度大、速度高、波阻抗值大的特点，利用地震常规预测手段较难预测出小裂缝型储层，而塔中地区奥陶系碳酸盐岩大裂缝型、裂缝-孔洞型、孔洞型、洞穴型储层具有密度小、速度低、波阻抗值小的特点，与围岩具有较为明显的差异，在地震上可以产生明显的响应，可利用常规地震资料来预测这种类型储层。

Taking the development platform of HVDC power transmission for example, the calculation result of impedance-frequency characteristic of traditional line commutated converter and that of FCC are compared. Simulation results show that the impact of impedance-frequency characteristic of converter on the resonance frequency of AC system is not negligible, and FCC can enhance the strength of AC system in a certain extent, improve system stability and effectively reduce AC equivalent impedance under resonance frequency, thus the harmonic instability of HVDC power transmission system can be avoided.

以直流输电开发平台为例，对传统电网换相换流器(line commutated converter，LCC)与FCC的阻抗频率特性计算结果进行对比，仿真结果表明换流器的阻抗频率特性对交流系统的谐振频率有着不可忽略的作用，FCC在一定程度上提高了交流系统强度，改善了系统稳定性，有效降低了系统谐振频率下的交流等值阻抗，从而更好避免直流输电系统谐波不稳定现象的发生。

This research adopts the impedance marching method, by varying duty cycle in a DC-DC converter to make the apparent load impedance matching with current system impedance, and reach the mpp operation.

控制电路的部分由单晶片PIC18F452为中心，重点为如何有效的取得太阳电池的开路电压及短路电流，以便正确计算出太阳电池的内部阻抗。

This research improves the impedance marching method, by varying duty cycle in a DC-DC converter to make the apparent load impedance matching with current system impedance, and reach the mpp operation.

本论文是改善阻抗匹配法，使其在不同照度下皆能准确做最大功率点追踪，并且应用阻抗匹配法在实际的太阳光能发电系统，经由调整DC-DC转换器中的主动开关之责任周期来达到负载与太阳能板的匹配，达成最大功率传输。

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