非线性偏置条件下隧道二极管中的触发振荡

本文提出了一类在非线性偏置条件下,由N-型负阻器件构成的具有三个奇点(其中有两个奇点在负阻区)的触发振荡电路。借助于点变换方法研究了该电路的工作特性。分析表明,所提出的电路具有足够宽的触发振荡工作区。用隧道二极管进行了实验,实验结果与理论有较好的符合。     

小注入下晶体管I_c-V_(BE)特性的指数因子的研究

本文讨论了影响小注入下晶体管的l_C-V_(BE)特性的各种因素。作者发现发射结势垒区准费米能级降落的影响对于解释实验中发现的n~*≡d(V_(BE)/V_T)/d In l_C<1的情况是重要的。 文中也给出了精确测量集成晶体管对的n~*值的差分方法。     

“现代几何光学”特点简介及体会

“现代几何光学”特点简介及体会易明（南京大学物理系，南京２１０００８）１《现代几何光学》产生的时代背景自激光出现以及电脑发展以来，激光技术、光纤通讯、集成光学、ＧＲＩＮ光学（ＧｒａｄｉｅｎｔＩｎｄｅｘＯｐｔｉｃｓ──变折射率光学）的发展，各种光声电信...     

K9玻璃低压下的双折射效应研究（Ⅱ）

继文献[1]之后,我们又用激光外差干涉仪测量了K9玻璃低压(0～3.5kg)下的双折射率,发现△~n_o～F和△~n_o～F呈不同的变化规律,这个现象是由样品内部应力分布的不均匀所导致的,反映了实际天文透镜自重引起的双折射率变化。     

自然弯扭梁广义翘曲坐标的求解

提出了自然弯扭梁受复杂载荷作用时静力分析的一种理论方法,重点在于对控制方程的求解,其中考虑了与扭转有关的翘曲变形和横向剪切变形的影响．在特殊的情况下,可以比较容易地得到这些方程的解答,包括各种内力、应力、应变和位移的计算．算例给出了平面曲梁受水平和垂直分布载荷作用时广义翘曲坐标的求解方法．计算结果表明,求得的应力和位移的理论值和三维有限元结果非常接近．此外,该理论不限于具有双对称横截面的自然弯扭梁,同样可推广至具有一般横截面形状的情况．     

VISUALIZATION OF UHF ACOUSTIC TRAVELING WAVEFRONT BY CW LASER:THEORY AND EXPERIMENT OF SPATIAL AND TEMPORAL CORRELATION

Using spatial and temporal information correlation theory which is different from the idea oftraditional stroboscope geometrie imaging formation,we've described how to obtain the opticalphase figure of UHF acoustic traveling wavefront in space by CW laser beam and convert it into anamplitude figure.We've also described that there is temporal frequency spectrum in spatialfrequency spectrum,and summarized the methods to get a 2-D high contrast optical figure ofacoustic traveling wavefront by correct spatial filtering concepts so as to clarify some confusions inusual acoustic imagng formation explanation. The experiment and some interesting results have been obtained.As an example,we've obtainedsuccessful results for 37.5 MHz ultrasonic traveling wave from not only bulk wave but also SAWdevice.The method is in real time and simple.We may expect that it becomes a method thatpromises well in researches on ultrasonic waves.     

调制半导体激光显示超声行波波前

本文在时域信息相关理论的基础上，提出了一种简便的用连续调制的半导体激光束显示超声行波波前的方法，实验上得到了证实。     

K9玻璃低压下的双折射效应研究

研究K9玻璃在低压下的双折射效应,测量它的双折射率及其梯度。结果表明,当K9玻璃用作天文透镜材料时,应充分考虑其自重引起的对透镜光学性能的影响。     

Solution of generalized coordinate for warping for naturally curved and twisted beams

A theoretical method for static analysis of naturally curved and twisted beams under complicated loads was presented, with special attention devoted to the solving process of governing equations which take into account the effects of torsion-related warping as well as transverse shear deformations. These governing equations, in special cases, can be readily solved and yield the solutions to the problem. The solutions can be used for the analysis of the beams, including the calculation of various internal forces, stresses, strains and displacements. The present theory will be used to investigate the stresses and displacements of a plane curved beam subjected to the action of horizontal and vertical distributed loads. The numerical results obtained by the present theory are found to be in very good agreement with the results of the FEM results. Besides, the present theory is not limited to the beams with a double symmetric cross-section, it can also be extended to those with arbitrary cross-sectional shape.