导波

PIC results show that the occurrence of absolute instability is determined by the operating current.

通过PIC模拟，给出了采用无损耗波导结构，且工作电流为25A和10A条件下的放大器频谱图和功率图，结果表明绝对不稳定性的出现与否主要由工作电流是否超过起振的阈值电流决定，损耗波导是抑制绝对不稳定性的有效手段。

Based on the characteristic equation of THz electromagnetic wave in metallic hollow waveguide, the dependence of the transformation attenuation and phase constant on the frequency of THz wave, inner radius of the waveguide and conductance of the metal material using Newton-Raphson iterative method.

从其传输的特性方程出发，利用Newton-Raphson迭代方法数值模拟了传输损耗和相位常数随太赫兹波频率、波导内径以及波导中金属镀层的电导率变化关系。

Using finite difference time domain method, the electromagnetic field distribution of THz wave is simulated in a THz 2D PC splitter and by plane wave expansion method the dispersion relation and defect modes are achieved in a THz rotated PC waveguide.5. A woodpile three-dimensional (3D) PC with face-centered-tetragonal symmetry is one of the most popular 3D PCs because of its favorable band gap characteristics. Based on the woodpile fct lattice structure, we propose a novel woodpile THz lattice structure with comparatively decreased symmetry, better band gap properties and easy fabrication by varying some structure parameters.

计算结果为利用非线性光学差频方法产生THz辐射源的实验研究提供了深入和全面的理论基础；四、利用平面波展开法，通过改变二维THz光子晶体的结构参数，对二维THz光子晶体完全带隙进行了优化，分析出两种适合工作在THz波段的二维光子晶体结构；采用时域有限差分法和平面波展开法，计算出THz波在二维光子晶体"T"型分束波导，45度旋转波导中传输的电磁场分布以及缺陷模；五、Woodpile面心立方四角结构是三维光子晶体中被研究最广泛的结构之一。

According to the field plot of TE10 wave mode in rectangular ridged waveguide,the equivalent capacitance and equivalent inductance are approximately calculated by quasi-static method,and the resonant frequency which is namely cutoff frequency is derived.

由矩形正脊波导中主模TE10波模的分布结构特征，用准静态方法近似的计算出等效电容和等效电感，从而计算出谐振频率，也就是矩形正脊波导的截止频率。

The research of optical waveguide theory is primitively focused on the area of the linear waveguides. With the rapid development of integrated degree and the prevalent using of the high optical power density, the nonlinear phenomenon appearing in the nonlinear waveguide attracts more and more attention.

最初光波导理论研究的波导多为线性光波导，而随着集成化程度的不断提高，强光源的普遍使用，光波导中出现的非线性效应已倍受关注，对光波导中的非线性效应的研究成为必需。

Based on the scheme, we have fabricated successfully many phase elements in LiNbO3: Fe, such as photorefractive phase mask, phasing zone plate, lens array, Daman grating and array waveguides, ring and elliptic waveguides and so on.

按照此方案，我们在LiNbO3：Fe晶体中成功制作了光折变位相图、相位型波带片、透镜阵列、达曼光栅及阵列波导、圆形及椭圆形波导等位相元件。

It presents many kinds of shock wave mechanisms and oscillating-tooth structures which may be selected in design. It also provides the theoretic basis for improving the performance of the oscillating-tooth machiner...

首次提出了可供设计选择的各种激波机构和活齿结构，为改善活齿波导传动的性能，研制新型的活齿波导传动提供了理论根据。

The characteristics of this copolyimide in chemistry and photics were determined.High quality copolyimide film could be obtained by casting the copolyimide solution on glass plate.Then the copolyimide was made into waveguide by using advanced processing techniques.Test results at optical co...

共聚物材料在溶液状态下用旋涂法获得了较高质量的共聚物薄膜，并在此基础上采用先进的光波导工艺技术将该材料制备成条波导，测试结果表明该波导在光通信波段1550nm处的平均传输损耗小于0.66dB/cm，局部损耗在0.2dB/cm，进一步改进后有望获得性能优异的光电子器件。

The Y branch of low-loss and wide branch angle can be used as power dividers/combines in modulators, switches, interferometric devices, semiconductor laser arrays, planar silica-based waveguide lasers.

本论文在最后还应用改进的广角光束传播法研究和设计了新型的低损耗Y分支波导结构，这种波导结构同时具有大分支角度的特点，在光波导开关、M—Z干涉仪等光器件中具有重要的应用。

The purpose of this paper is to extract the coupling matrix of generalized chebyshev filter, model the four-port rectangular junctions, multiple-stepped rectangular waveguide bend and T-septum rectangular waveguide junction by full-wave methods and design generalized chebyshev filters and diplexers. The main works are as follows: 1. Systematically research on the theory of generalized chebyshev filters The generalized chebyshev filters are based on the all-coupled model.

本文主要目的是研究广义切比雪夫滤波器拓扑结构、物理结构上可实现的耦合矩阵提取及其特性分析和基于模式匹配法全波建模四口矩形结、多阶梯矩形波导弯头、T—scptum矩形波导接头，最后，设计了一系列高性能的滤波器和双工器。

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。