动载荷下弹塑性随动强化结构的安定问题

本文讨论了弹塑性随动强化结构的动力安定问题,其加载面在应力空间中是任意形状的凸曲面。文中给出了相应的安定定理,指出如果能找到任何一个与时间无关的和虚设残余应力而使结构安定,则该结构将一定是动力安定的。此外,本文还给出了塑性功和塑性应变的上界估计式,并以在交变载荷作用下的Mises随动强化材料的简支圆板为例,对定理的应用进行了说明。     

A STUDY ON SECONDARY DEFECTS IN SELF-ION IMPLANTED Si

By using the cross-sectional transmission electron microscopy (XTEM), Rutherford backscattering (and channeling) spectrometry (RBS) and high-energy electron beam irra-diation technology with a high voltage electron microscope (HVEM), secondary defects in self-ion implanted Si has been studied. The result shows that the depths of secondary de-fect bands are related to the implantation energies, and the values of depths are slightly greater than the projected ranges of self-ions implanted into Si. In the higher energy region (>1MeV), the former exceeds the latter by nearly 0.2-0.4μm. Experiments indicate that the pre-implantation damage (the primary defect), on one hand, will superpose on the primary defects of post-implantations and make secondary defects increase, and on the other hand, it will also provide an enhanced-diffusion region for vacancies and interstitials created by the post-implantation and reduce the formation of secondary defects. Experiments also show that dislocation loops in secondary defect bands of self-implanted Si are interstitial in nature.     

A Novel Method to Calculate the Initial Phase Difference between the Two Fibre Arms of Laser Homodyne Iuterferometer

We suggest a novel method to calculate the initial phase difference between two fibre arms of a laser homodyne interferometer. Put the two fibre arms in a temperature controller, whose short term stability is 0.02° C （measured in an hour）, then measure the interference photocurrent and the photocurrents from the two fibre arms at a fixed temperature. With these three photocurrents we can calculate the value of the initial phase difference. We set up a simple laser homodyne interferometer to test the theory. The experimental results are repeatable and the measurement precision is about 0.04°. It is theoretically and experimentally proven that this method is potentially easy and practical.     

Numerical Analysis of Nano-Aperture Light Source for High-Density Optical Data Storage

Two unconventional nano-aperture light sources, an L-shaped nano-aperture source and a 3D nano-aperture source for high-density optical data storage, are numerically investigated. With incidence of a Gaussian beam, the spot size of the Poynting vector coupled into the recording medium is 130 × 175 nm^2 for the L-aperture and 120 × 135 nm^2 for the 3D nano-aperture. The quantitative analyses indicate that the unconventional nanoaperture sources can provide enough power density to record marks in the commercial recording medium. It is feasible to use a laser diode with a nano-aperture as an active nanometer light source for high-density optical data storage.     

在有机化学课中培养学生能力的探索

高等学校的教学工作在智育方面担负着两项重要任务:一是传授知识,二是培养能力,而后者比前者更为重要。五年来,我和教研室的同志们在有机化学课的教学中,对如何培养学生能力进行了探索,并取得了一定的效果。     

ICP-AES法同时分析饲料资源中多种元素

某些饼粕、糟渣和青饲料,虽早已成为我国的传统饲料,但其营养价值尚未进行系统的研究和评价。目前,饲料工业已在国民经济中显示出巨大的经济潜力和作用,“饲料开发技术”已列为国家重点科技项目之一,资源调查与产品检验已列入日程,饲料及其资源中营养元素和有害元素的分析必不可少。 ICP-AES法分析饲料中多种元素,由于其良好的分析特性完全可以取代常用的化学法、比色法和原子吸收光谱法。我国饼粕、糟渣和青饲料资源品种繁多,成份各异,用一种通用的ICP-AES法分析这些样品,以评定和调查其质量,从信息容量、信息比价、时效性和适用性来说都十分有吸引力。本文报告了ICP-AES法同时测定饲料资源中Ca、Mg、Al、Fe、P、Cu、Zu、Mn、Ba、Sr、Co、Pb、Cd含量。本法应用于饲料资源调查与评价获得了令人满意的效果。     

利用溴化十六烷基吡啶和1-(2-吡啶偶氮)-2-萘酚光度法测定铜

1-(2-吡啶偶氮)-2-萘酚(PAN)能与许多金属离子形成有色络合物,是光度法中应用较广泛的试剂,其缺点是选择性较差。PAN及其络合物都难溶于水,需与萃取过程连用。近年来已有资料报导用表面活性剂加PAN增溶光度测定锌、钴、镍及锰。我们研究了在溴化十六烷基吡啶(CPB)存在下铜与PAN反应的条件,制定了CPB-PAN增溶光度测定铜的方法。与萃取光度法相比,除能在水相直接测定外,扩大了符合比尔定律的范围,,以邻菲罗啉使铜褪色作为参比液,可以消除     

电化学调制时间分辨紫外可见光谱技术及其在电显色研究中的应用

七十年代发展起来的电化学现场(in situ)谱学技术将电化学学科的研究推向分子水平。随着研究深入到分子动态过程,时间分辨谱学技术愈显得重要。紫外可见光谱是检测含π电子、非键电子(如N,O,S,卤素原子)基因、无机配合物分子和电荷转移复合物分子的重要手段。包含这些基团的体系在电化学和生命科学中广泛存在,认识其动态行为意义重大。但目前快速扫描法测量一条紫外可见光谱,最快只能达5ms。近年来,发展起了一种新型光谱探测仪器——光多道分析仪(Optical Multichannel Analyzer,OMA)。其核心由自扫描光敏二极管列阵或光导摄象管构成,能够对多个检测通道(象元)同时完成光电转换。它具有测量速度快、灵敏度高的优势。