采用边界元法研究槽形波导的色散特性

本文提出了用边界元法分析槽形波导的方法。推导出了有关表达式,并对一典型例子进行了研究,计算了其色散特性;得到的数据均与其它方法的结果相吻合。由于本文方法推导简单,计算省时,所以是研究此类问题的有效途径。     

NMR parameter contrast in abundant-spin images of solids

Solid state nuclear magnetic resonance imaging (NMRI) techniques have been steadily improving over the years. Today high-resolution images of rigid solids are now accomplished by many different means. For abundant nuclei, the combination of multiple-pulse line narrowing and pulsed field gradients have greatly improved both the resolution and sensitivity of the imaging experiment, but often at the expense of the chemical information in the material. In this paper we discuss means of incorporating NMR parameters in the imaging experiment to generate image contrast which provides information about local variations in the chemistry of the material.     

Double semiconductor substrate in overlay shielded superconducting microstrip lines

The Transverse Transmission Line (TTL) is used in the theory of the overlay shielded microstrip lines considering the superconductor strip on two semiconductor regions. The superconductor effect is included with the boundary condition of the surface impedance, that is related to the complex conductivity of the material, calculated from the advanced two-fluid model. Applying the moment method the complex propagation constant of the structure, including the phase constant and the attenuation constant, is obtained. Results are presented for the complex propagation constant, versus the frequency and the temperature, of this overlay superconducting microstrip lines.     

一种电视倍行处理电路的实现

本文成功地设计了包括行重复和行内插在内的倍行处理电路,来抑制和消除行间闪烁及爬行现象,提高图像质量。并通过实验观察了倍行处理的实际效果。     

Line narrowing beyond natural linewidth in radiation matter interaction

A review of the various linear and nonlinear methods used to obtain resolution beyond natural linewidth is given. Based on the lecture given at the International Symposium on Theoretical Physics, Bangalore, November 1984.     

A modification of Armijo's step-size rule for negative curvature

Armijo's step-size procedure for function minimization is modified to include second derivative information. Accumulation points using this procedure are shown to be stationary points with positive semi-definite Hessian matrices.This research was supported by the United States Army Research Office.     

The Resonant Wave Numbers of Eccentric Ring Microstrip Antennas for All Modes

The method, connected with the concentric ring microstrip antenna and based on the perturbation , for the resonant wave numbers of eccentric ring microstrip antennas for all modes is suggested. The usefulness and accuracy of the method is shown through the comparison of the calculation used here with the measurement and other method from the reference.     

集成式微带渐变线特性的快速计算方法及性能分析

集成式微带渐变线广泛用于有源电路的宽带匹配中，其特性的快速计算方法是构成电路ＣＡＤ的关键。本文将特性求解归结为一联立微方程组，并对其作分区（区段数为Ｎ）积分，积分过程中将主要变量进行线性拟合，解得一组快速失方程，从而获得一种新计算方法。这种方法具有分段区间数小，计算速度快等特点。最后采用本文方法对几种常用渐变线进行了特性计算与性能对比分析，得到了有益的结论，表明本文方法具有很好的实用价值。     

1.65μm附近CH_4分子高分辨率吸收光谱研究

采用连续可调谐二极管半导体激光器为探测光源,以可调怀特型长光程多通池(46.36～1158.90m)作为吸收池,采用直接吸收的方法,探测了室温下1.65μm附近CH4分子的高分辨率吸收光谱。在6043.00～6053.72cm-1范围内探测了5组不同压力和光程下的吸收光谱,观测到了259条线新的CH4分子吸收谱线,实验数据用Gaussian线型进行拟合,得到了这些吸收谱线的线强、线位置以及线强的标准偏差值,并对光谱中难以分辨的吸收谱线进行了分析。探测得到的最小谱线线强是4.3×10-27cm-1·(molcule·cm-2)-1,吸收谱线线强大于3.0×10-24cm-1·(mol·cm-2)-1由于吸收饱和而未被处理,同时所测得的光谱也显示出CH4分子在1.65μm附近有非常丰富的弱吸收谱线和复杂的结构。文中所报道的吸收谱线都是HITRAN2004数据库中所未报道的,而且也未见有其他文献报道过。     

Linewidths of ammonia in collisions with He: Calculations from an ab initio potential

We present semiclassical calculations based on the Robert-Bonamy formalism of collisional broadening coefficients of ammonia by collision with He at room temperature. Calculations have been performed with the accurate ab initio potential of Hodges and Wheatley. The calculated line widths are compared to the available experimental data and a satisfactory agreement is found, although the model contains no adjustable parameters. However the calculations also exaggerate the K dependence of the broadenings, especially for lines with K = J − 1 or K = J.