查询词典 impedance

A series of theoretical and experimental studies on the microstrip patch antennas with dielectric superstrates is carried out systematically. Firstly, a comprehensive survey of the microstrip antenna technology and its theories are presented. Then, two analysis techniques, named as the spectral domain Green's function method and the spectral domain integral equation method are developed. The SDGF method is a simplified analysis technique, which takes advantage of the spectral domain immittance approach to find the dyadic Green's function for the stratified media, and obtains the complete closed-form formulas for radiation patterns, directivity, efficiency, gain etc. Some interesting calculated results are presented. The SDIE method is capable of determining resonant frequency, radiation characteristics, input impedance etc, for the covered microstrip patch antennas. Comparing with other full-wave analyses it reduced computation and mathematical labour remarkably. The singularities near the pole location of the surface-wave modes and the difficulty of the integral computation over infinite range of oscillating integrands are dealt with actively and documented well. Results predicted by the SDIE method agree extremely well with our experimental results for resonant frequencies of various superstrates. The superstrate effects on impedance and radiation characteristics also have been investigated experimentally so that the gap due to lack of measured data and computed results for multi-layered superstrate has been filled to some degrees and two useful observations have been achieved for weakening the resonant frequency shift and optimizing the microstrip antenna gain. As a meaningful application, the design and analysis of a 4×4 patch array are introduced.

实用微带天线普遍加介质覆盖层来防护热，物理损伤和环境影响，也可能在飞行或严酷气候条件下自然形成覆盖层本论文对带介质覆盖层的微带贴片天线系统地作了一系列理论和实验研究首先，对微带天线技术和理论作了全面的综述然后，发展了两种分析方法，称为谱域格林函数法和谱域积分方程法SDGF法是一种简化的分析技术，它利用谱域导抗法来求得分层媒质的并矢格林函数，并得出方向图、方向性系数、增益等参数的完整的闭式公式，给出了一些令人感兴趣的计算结果SDIE法能确定介质覆盖微带天线的谐振频率、辐射特性和输入阻抗等与其它全波分析方法相比，它明显减小了计算量和数学工作量已有效地处理了表面波模极点附近的奇异性和对振荡的被积函数的无限区间积分计算的困难对于不同覆盖层情况下的谐振频率，由SDIE法所预示的结果与我们的实验结果吻合得很好对于覆盖层对阻抗和辐射特性的影响也已作了实验研究这在某种程度上填补了缺少实验数据和计算结果之间的间隙，并得出了缓解谐振频率偏移和优化天线增益的两点有用的结论作为有意义的应用，介绍了一个4×4元矩形贴片天线阵的设计和分析。

To suit it for this usage, the ideal operational amplifier would have infinite input impedance, zero output impedance, infinite gain and an open-loop 3 dB point at infinite frequency rolling off at 6dB per octave.

为了得到这样的特性，理想 OP 应该有无限大的输入阻抗，0 输出内阻抗，无限大的增益，无限大的开环增益带宽(3dB 带宽)，以及其 6dB/每 2 倍频程的频率滚降。

There are many electrochemical methods for measuring the diffusion coefficient of lithium in carbon such as Electrochemical Impedance Spectra method、Potential Step Chronoamperometer 、Potential Intermittent Titration Technique 、Current Pulse Relaxation and Warburg impedance methods.

测试锂在碳材料中扩散系数常用的方法有电化学交流阻抗图谱法、电位阶跃时间电流法、电位间歇滴定法、电流脉冲驰豫法和Warburg阻抗法等。

Calculating formula of wave impedance is obtained by main values of the inverse tangent function of phase_shift at two neighboring frequencies and the corresponding integral character of phase_shift is denoted as the convergent criterion of wave impedance inversion.

利用复合反射系数中多个频率点的相移反正切函数主值，给出了波阻抗的计算公式，并把套管-地层环空间介质中波的相移的整、实特性作为波阻抗反演收敛的判据。

Based on conducting P/S wave joint inversion formula and ascertaining the inversion process, we make the P/S wave inversion of some seismic line of Sulige gas field, obtain the P wave impedance, S wave impedance and the V/V and limit distribution range of low speed mudstone, tight sandstone and effective sandstone respectively.

据此，在推导纵横波联合反演公式和确定反演过程的基础上，对苏里格气田某测线进行纵横波联合反演，得到纵波阻抗、横波阻抗和纵横波速度比，从而确定了低速泥岩、致密砂岩与有效砂岩的分布范围。

The irrational impedance function is applied to the synthesis design of the regulating network[1][2], its regulating accuracy depending on the approximate times of the impedance function.

无理阻抗函数用于调节网络综合设计，其调节精度将取决于阻抗函数的近似次数。

The effects of longitudinal elastic wave impedance and joint impedance on transmission and reflection efficiency are analyzed.

因此，开展舰船结构声传递的阻抑机理和应用研究，具有重要的理论意义和实用价值。

The vibration transmission efficiency and reflection efficiency are determined as functions of longitudinal elastic wave impedance and joint impedance.

舰船结构声传递的阻抑机理与应用研究，是一个涉及结构声、结构振动和弹性波控制的交叉领域的研究课题。

Again, this is a somewhat idealized assumption in that it assumes that the operator can determine that all remote phones are on-hook, that those phones truly represent high impedance in the ADSL band, and that if an ADSL modem is present at the remote, there is some means to force it into a high-impedance state.

再次，这是一个有些理想化的假设，假定操作员能确定所有的远程电话是挂机的，那些电话代表ADSL带宽中的阻抗，如果远端有一个ADSL调制解调器的话，有一些办法可以让它强制进入高阻抗状态。

Impedance pneumography FZ-1 is of value in determining the therapeutic effects of drugs and following up, it also to be used in diagnosing disorders due to respiratory impedance changes of increased airway resistance or decreased lung compliance or both.

认为该仪器对于气道阻力增加和肺顺应性降低等呼吸阻抗改变疾病的诊断，以及判断药物疗效和病情随访有较大价值。

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