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。     

有机胂化合物的研究 Ⅳ.溴化α-噻吩甲酰基代甲基三苯鉮的合成及其与芳胺的反应

本文报道了溴化α-噻吩甲酰基代甲基三苯鉮的合成及其与取代苯胺,α(β)-萘胺的反应,并合成了一系列2-(α-噻吩基)吲哚和苯骈吲哚化合物。经元素分析、红外光谱和核磁共振谱及吲哚环的显色反应,确证了产物的结构。     

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.     

食品中多元素的ICP发射光谱分析

测定食品中常量和微量元素,是目前人们较关心的问题,因为它关系到人体所必需的有益元素的提供,以及对有害元素的污染控制。以前这种分析大多采用原子吸收光谱、原子发射光谱以及化学分析方法。近几年来,电感耦合高频等离子体发射光谱(ICPES)成功地应用到许多方面,证明它是一种较满意的分析方法,在食品分析方面也是如此。本文报告了ICPES分析饼干、乳制品、糖果等儿童食品中的Ca、Mg、Fe、Al、P、Sr、Zn、Cu、Mn、Cd、Mo、Pb、As、Se等元素,并对分析过程中出现的几个问题进行了讨论。     

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.     

Formation and photoluminescence properties of boron nanocones

This paper reports that a simple chemical vapour deposition method has been adopted to fabricate large scale, high density boron nanocones with thermal evaporation of B/B2O3 powders precursors in an Ar/H2 gas mixture at the synthesis temperature of 1000-1200℃. The lengths of boron nanocones are several micrometres, and the diameters of nanocone tops are in a range of 50-100 nm. transmission electron microscopy and selected area electron diffraction indicate that the nanocones are single crystalline α-tetragonal boron. The vapour liquid solid mechanism is the main formation mechanism of boron nanocones. One broad photolumineseence emission peak at the central wavelength of about 650 nm is observed under the 532 nm light excitation. Boron nanocones with good photoluminescence properties are promising candidates for applications in optical emitting devices.     

Ga(Ⅲ)与EHPG配合反应的光谱研究

在0.1mol/L pH 7.2,Tris-HCl缓冲溶液和室温条件下,用荧光光谱和紫外差光谱研究了Ga3 与N,N'-乙烯-二[2-(2-羟基苯基)甘氨酸](EHPG)的配合反应.结果表明:Ga3 与EHPG的配位比为1/1.随着Ga3 的不断滴加,EHPG的荧光光谱在310nm处的最大荧光峰强度逐渐降低,其紫外差光谱在240nm和293nm处的吸收峰逐渐增强.当Ga3 达到一定量时,310nm处的荧光强度、紫外光谱中240nm和293nm处的吸收峰强度不再发生变化.通过计算可得:在240nm处配合物Ga-EHPG的摩尔吸光系数为ε=5.41×103 L·mol-1·cm-1,条件稳定常数为lgKGa-EHPG=22.83.