导波

The formation mechanism of the absolute instability and gyrotron backward wave oscillations is analyzed, and the methods to suppress the parasitical modes are discussed.The nonlinear theory model of gyro-TWT is consummated by considering the influence of tapered magnetic field and waveguide radius, electron velocity spread, and waveguide loss on electron beam-wave interaction. The large-signal characteristic of gyro-TWT, such as launching loss and absolute instability, are also analyzed in detail. This work establishes the foundation for the development of a gyro-TWT amplifier.

重点研究了两段损耗波导结构和损耗陶瓷结构回旋行波管中的电子注-波互作用，分析了绝对不稳定性和回旋返波振荡的形成机制和抑制寄生模式的方法；完善了回旋行波管的非线性理论模型，并考虑了磁场和波导半径渐变、速度零散、波导损耗等因素对注-波互作用的影响；详细分析了发射损耗、相位稳定性等回旋行波管的大信号特征，为回旋行波管放大器的研制奠定了基础。

The modification occurred in crystal lattice and the restoration effect of annealing are discussed by analyzing the intensity, width and angle of the X-ray diffraction peaks. The H〓 concentration and related structural information are deduced by the evolution of OH〓 absorption spectra with annealing, which offers the experimental proof for further discussion on annealing. The disappearance of the OH〓 absorption peak at 3300cm〓 after annealing indicates that some H〓 of high concentration diffused further into the substrate and the crystal phase changes accordingly.

根据质子交换波导退火前后在OH〓吸收峰特征的变化，推断波导层H〓浓度及相关的结构信息，并对进一步分析退火机制提供了实验依据；由于3300cm〓〓处的吸收峰代表的是立方钙钛矿的HNbO〓结构成分，因此退火后该峰的消失确实说明高浓度区域的H〓继续向波导深度迁移的事实，同时波导区的晶相成分也发生变化。

Finally, applications of the anomalous propagation of microwave in tropospheric ducts are discussed: in connection with concrete radar parameters, effects of ducts on radar range and detection performance are discussed, the results obtained are of great value for the overall design of radar systems; by use of the interference standards of ITU-R, the co-ordination area of satellite earth-station under tropospheric ducts environment is studied ; by explaining the relationship between evaporation duct and advection fog, a new way to forecast sea advection fog from evaporation duct is provided.

最后讨论了对流层大气波导环境下电波异常传播特性的应用：结合具体的雷达系统参数，模拟计算了大气波导对雷达作用距离及发现概率的影响，对雷达系统的总体设计具有重要的参考价值；对表面大气波导环境下的卫星地球站通信协调区域进行了确定，从理论上很好地给出了协调距离量级的概念，为卫星地球站与地面微波站之间的协调提供了依据和参考；分析了利用海面蒸发波导来快速预测平流海雾的新方法，完善了平流海雾的预报方法，对海上安全作业和生产具有重要的意义。

Combining the definition of CWT and the derivative property of convolution, we constructed a general method to calculate the approximate derivative of signal through CWT by using the first and second derivative of Gaussian function, Haar, and the first derivative of three-order-Spline function as wavelets. As compared with the other approaches of calculating derivative, which include the numerical differentiation, polynomial filters, Fourier transform, and the recently proposed DWT method, fast calculation and simple mathematical operation were remarkable advantages of CWT method. For the signal corrupted by severe noise (Signal-toNoise Ratio=5), the satisfactory results could also obtained via CWT method through appropriately adiusting the dilations.

在此基础上，(1)结合连续小波变换的特点和卷积的微分性质，提出了使用Gaussian函数的一阶和二阶导数，Haar和三次样条函数的一阶导数作为小波函数的连续小波变换计算信号近似导数的一般性方法，与其他导数计算方法(包括数字微分法，多项式滤波法，Fourier变换法和离散小波变换法)相比，本法简单便捷，计算速度快，对于噪声含量较高的信号(S/N为5)，只要适当调节尺度即可获得比较满意的结果。

Initial numerical results indicate that the pentagonal waveguide proposed have more power carrying capability and higher power capacity than rectangular and elliptical ones.

初步的数值分析表明：与目前常用的高功率波导——矩形波导和椭圆波导相比，五边形波导具有更强的功率携带能力和更大的功率容量，因而具有很大的实用价值。

Based on orthogonal function unfolding theory, the transverse fields can be represented as a superposition of waveguide modes. And according to coupled-wave theory, the time-dependent multi-mode coupling-wave equations (or the generalized telegrapher's equations) and the coupling coefficients among the different modes were deduced. The generalized telegrapher's equations are a set of coupled one-dimensional partial differential equations for the amplitudes of the modes.

应用正交函数的展开理论，将变截面波导中的电磁场表示为横电波和横磁波本征模式的级数；然后根据耦合波理论，推导了考虑波导金属壁有限电导率的变截面波导时域多模耦合波方程组及各模式间耦合系数的表达式。

An approximate analytical approach, which can be used to analyze the optical characteristics of metal-clad step or graded index waveguides in near cutoff, is presented at first. The mode propagation characteristics of metal-clad step index waveguides in near cutoff are comprehensively analyzed.

GaAs/GaAlAs异质结光波导材料是目前集成光学中的重要材料，本论文在系统介绍外延生长技术的基础上，利用普通的液相外延炉，成功地生长出可用于光波导器件制作的、表面较光滑并具有较大面积（14×16mm〓）的GaAs/GaAlAs异质结光波导材料，C-V法测得波导层载流子浓度为2—4×10〓cm〓，Al-Schottky接触的反向电压大于20伏，平板波导和脊波导通光实验良好。

A novel Y branch waveguide structure is presented, in which a transitional guide is embedded between an incident channel and an output branch.

提出了一种新型的Y分支光波导结构。该Y分支波导由一个入射波导、一个过渡波导和一对出射波导组成。

Narrow wall and broad wall apperture coupler. Experiments have been made to test them. Other types of discontinuity we have studied include: coax and SIW transformer; SIWs\' coupling on different layers; branch coupler based on SIW; post inside SIW; the H-plane discontinuity ; bend structures; cross structures; \'Y\' branch of SIW etc.

本文所研究的其它不连续性结构还包括：同轴波导与SIW的转换接头；不同层间SIW的转换；基于SIW的分支定向耦合器；基片集成波导中的感性金属杆；基片集成波导的H面不连续性结构；各类拐角结构；波导交叉结构；波导'Y'分支结构。

Through the analysis, we also find that the change of defect waveguide edge dielectric rod radius and wave guide\'s width are advantageous for enhancing the coupling efficiency of waveguide with the resonant cavity.3. The coupling relation of between the resonant cavity and waveguide has been analyzed, and according to the coupled mode theory, transmission coefficient expression of every port has been derived.

通过分析也发现适当改变缺陷波导边缘介质柱的半径、缺陷介质柱与波导间介质柱的半径及波导的宽度，都有利于提高波导与谐振腔之间的耦合效率。3、从理论上分析了谐振腔与波导间的耦合关系，根据耦合模理论导出了各端口传输系数的表达式。

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。