查询词典 stratified sample

Hypolimnion The lower noncirculating water in a thermally stratified lake.

下层滞水层，均温层：在热层结湖中位置较低的不循环水层。

For stratified and cluster sampling with inappreciable differences, estimate precision becomes poor.

对于分层抽样和整群抽样，当群体间的差异、群内个体间差异均不显著时，其估计精度往往都很差。

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。

The inserts are large with an iC, inscribed circle diameter, of 19 mm and a thickness of 6 mm with a composition of 5-10 wt-% Co, 5-12 wt-% cubic carbides or carbonitrides of the metals Ti, Ta and/or Nb, and balance WC with a stratified binder phase enriched surface zone 15-40m thick.

刀片很大，其内接圆直径iC≥19mm，厚度≥6mm，其组分为：5-10wt％的Co、5-12wt％的金属Ti、Ta和/或Nb的立方碳化物或者碳氮化物，并且其余为WC，分层富粘结相表面区域为15-40μm厚。

The harmonic field of electric dipole source on the uniform earth surface is converted into transient field by inverse Laplace transform,and the Bz/ t transient curve is calculated.The Hz transient curves on the stratified earth surface are obtained from cosine transform calculated by broken line approximation.

由逆拉普拉斯变换将均匀大地面上的电偶极子源谐变电磁场转换为瞬变电磁场，并计算出Bzt瞬态曲线；对分层大地面上的瞬变电磁场，采用折线逼近法计算余弦变换得出Hz瞬态曲线。

This system is a rigidly stratified one, which took Shengmuyuanjun as the head and linked with blood relationship. As the spokesman of the ideal of Taoism, they reflected Taoists pursuit of mercy, kindheartedness and living forever.

杜光庭对道教的另一贡献是他创造性的建立了一个以圣母元君为首、以血缘关系为纽带、等级森严的女仙体系，并以她们为道教终极理想的代言人，宣扬道教对善、仁和长生不死的追求。

The alternative estimators used in this paper include least squares estimator, stratified weighted least squares estimator, probability weighted least squares estimator, and Quasi-Aitken weighted least squares estimator.

中文摘要抽样调查设计随著资讯需求的增加日益复杂，然若参数的估计方法无法配合所使用的抽样调查设计，则统计推论结果将难以达到预期的精确度。

Rotaing and stratified flow ; Rotating experiments ; Lee wave and lee eddies

旋转层结流；转槽实验；背风坡与背风涡旋

The lexicographically stratified method for multi-object optimal electric power network planning is presented according to the problem encountered in the research on multi-object electric power network planning.

针对目前研究大规模多阶段多目标电网规划遇到的问题，提出了多目标电网规划的分层最优化方法，使得计算量大幅度降低，避免了多目标函数处理的困难；同时提出的改进最优切负荷模型更易于计算缺电成本，使可靠性指标转化为经济性指标时方便实用，算例证明了本文算法的有效性。

The purpose of this research is to analyze stratified life-style in Taiwan.

本文主要研究目的在於分析台湾社会中，不同阶层的生活风格。

But GST= 0.156, Nm=1. 588. As a result, the foundation of Youyongchi Avicennia marina population was the result of the migration of hypocotyles and human factors.

这项工作可以为海岸防护林中新引进种类的判定以及为研究种群建立者效应方法的确定提供科学依据。

The two-dimensional CDRC-ADI-FDTD update equations for collision unmagnetized plasma are induced. The unconditional stability of the CDRC-ADI-FDTD formulation for collision unmagnetized plasma is obtained by the examples.

推导了碰撞非磁化等离子体中的二维CDRC-ADI-FDTD迭代公式，并用算例验证了碰撞非磁化等离子体CDRC-ADI-FDTD算法也是无条件稳定的。