Electrical properties of polypyrrole/p‐InP structure

The polypyrrole/p‐InP structure has been fabricated by the electrochemical polymerization of the organic polypyrrole onto the p‐InP substrate. The current–voltage (I–V), capacitance–voltage (C–V), and capacitance–frequency (C–f) characteristics of the PPy/p‐InP structure have been determined at room temperature. The structure showed nonideal I–V behavior with the ideality factor and the barrier height 1.48 and 0.69 eV respectively. C–f measurements of the structure have been carried out using the Schottky capacitance spectroscopy technique and it has been seen that there is a good agreement between the experimental and theoretical values. Also, it has been seen that capacitance almost show a plateau up to a certain value of frequency, after which, the capacitance decreases. The higher values of capacitance at low frequencies were attributed to the excess capacitance resulting from the interface states in equilibrium with the p‐InP that can follow the a.c. signal. The interface state density N_ss and relaxation time τ of the structure were determined from C–f characteristics. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1572–1579, 2006     

An accurate method to predict the stress concentration in composite laminates with a circular hole under tensile loading

The paper presents a theoretical-numerical hybrid method for determining the stresses distribution in composite laminates containing a circular hole and subjected to uniaxial tensile loading. The method is based upon an appropriate corrective function allowing a simple and rapid evaluation of stress distributions in a generic plate of finite width with a hole based on the theoretical stresses distribution in an infinite plate with the same hole geometry and material. In order to verify the accuracy of the method proposed, various numerical and experimental tests have been performed by considering different laminate lay-ups; in particular, the experimental results have shown that a combined use of the method proposed and the well-know point-stress criterion leads to reliable strength predictions for GFRP or CFRP laminates with a circular hole. Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 43, No. 4, pp. 531–570, July–August, 2007.     

Nd掺杂的Bi4Ti3O12变温X射线衍射分析

利用变温X射线衍射技术，在预烧过程中分析了Nd掺杂Bi4Ti3O12后生成Bi3.15Nd0.85Ti3O12（BNT）相的形成过程以及微结构的变化．实验观察到以30℃／min的升温速率，BNT相在700℃时开始形成，其衍射峰强度随温度的继续升高而增强，衍射峰半高宽随烧结时间延长而减小．X射线衍射分析结果表明，在900℃恒温条件下，烧结约2h，可形成单一的BNT相．     

Pulsed pump: Thermal effects in solid state lasers under super-Gaussian pulses

Solid state laser (SSL) powers can be realistically scaled when pumped by a real, efficient and multimode pulse. In this work, a fourth-order super-Gaussian pulse was assumed as a pump for SSL’s and a complete analytical expression for the thermal phase shift is given. Moreover, the focal length of thermal lens in paraxial ray approximation regime was studied. The results when applied to a Ti: sapphire crystal show an appreciable correction for abberation compared to a top-hat pulse.     

ENSTAR detector forη- mesic studies

We have initiated a search for a new type of nuclear matter, theη-mesic nucleus, using beams from the multi-GeV hadron facility, COSY at Juelich, Germany. A large acceptance scintillator detector, ENSTAR has been designed and built at BARC, Mumbai and fully assembled and tested at COSY. A test run for calibration and evaluation has been completed. In this contribution we present the design and technical details of the ENSTAR detector and how it will be used to detect protons and pions (the decay products ofη-mesic bound state). The detector is made of plastic scintillators arranged in three concentric cylindrical layers. The readout of the detectors is by means of optical fibres. The layers are used to generate ΔE –E spectra for particle identification and total energy information of stopped particles. The granularity of the detector allows for position (θ and ?ø determination making the event reconstruction kinematically complete     

Studies on Solid State Reactions of Coordination Compounds（LXXI）──Solid State Reactions of o－Aminobenzoic Acid with Copper（Ⅱ） Acetate and Formate at Room Temperature

ＳｔｕｄｉｅｓｏｎＳｏｌｉｄＳｔａｔｅＲｅａｃｔｉｏｎｓｏｆＣｏｏｒｄｉｎａｔｉｏｎＣｏｍｐｏｕｎｄｓ（ＬＸＸＩ）──ＳｏｌｉｄＳｔａｔｅＲｅａｃｔｉｏｎｓｏｆｏ－ＡｍｉｎｏｂｅｎｚｏｉｃＡｃｉｄｗｉｔｈＣｏｐｐｅｒ（Ⅱ）ＡｃｅｔａｔｅａｎｄＦｏｒｍ...     

碳酸及碳酸酯热消除反应的量子化学研究

用AM1方法研究了碳酸和碳酸酯的热消除反应．发现迁移基团R和基团R’共同制约这类吸热反应的活化能。     

WS2 超细粉体的固相法合成

WS2 超细粉体的固相法合成;WS2;固相反应;过硫系数;高能球磨;粒度     

高分辨双晶XRF研究酞菁化合物中硫杂质的化学态

酞菁化合物是一种大π键共轭体系的平面分子结构，它以颜色鲜艳、化学稳定性和价格便宜等特点，已在颜料工业上得到了广泛地应用．随着高科技的发展，酞菁化合物的应用进入静电复印的领域．研究中发现：酞普化合物的晶体结构直接影响它的色泽、耐热性、稳定性以及光电导性．在诸多的酸苦晶型中，β-型酞菁是比较稳定的一种，其它晶型届亚稳态型．近年来，光敏性较好的X-型用于激光印刷机感光鼓的载流子产生层［1］．用作静电复印中的酞育粗颜料，一般多为a一型，且含有大量的有机和无机杂质[2]，经高温真空升华提纯后，转变为卢一型．有趣…