掺染料激光介质的研究

以PMMA为基质，在助溶剂的作用下掺杂激光染料Rh6G制备出了塑料激光介质样品，采用YAG激光器作为泵浦源测试了塑料激光介质的发射光谱，讨论了其激光发射机理。     

Alloy formation in mechanically activated mixtures

The physical mixtures of hydroxocarbonates of Cu and Ni with aluminium were activated using a laboratory planetary mill. The chemical reactions and alloy formations as the effects of grinding were followed by the phase analysis of solid products based on the thermogravimetry and X-ray diffractometry. Experimental evidence indicates that the nature of reactions and products of mechanical activation was dependent on the amount of aluminium and time of grinding. This revised version was published online in July 2006 with corrections to the Cover Date.     

Oblique reflection of shock waves from rigid porous materials

A study to determine the general gas dynamic behaviour associated with the impact of a shock wave on a porous wedge has been undertaken. A number of interesting features are noted. The pattern of wave reflection is shown to be significantly affected by the inflow of gas into the wedge. This has the effect of reducing the triple point trajectory angle for cases of Mach reflection and for strongly reducing the reflection angle in regular reflection. The permeability of the wedge has a significant effect on the strength of the reflected wave and in some cases this wave can be attenuated to the extent that it is almost eradicated. Pressure measurements taken under the wedge are characterized by oscillations which are of similar shape, for a given wedge, over a range of shock wave Mach numbers. It is shown that the wave transmitted into the wedge is attenuated to varying degrees depending on the material properties, and that for weak incident waves the mean propagation velocity can be less than the sound speed in the pore fluid. Photographs taken using a specially constructed wedge which allows the transmitted wave to be visualised, show that the transmitted wave is nearly plane.This article was processed using Springer-Verlag T_EX Shock Waves macro package 1.0 and the AMS fonts, developed by the American Mathematical Society.     

Effect of local alloy disorder on the emission kinetics of deep donors (DX centers) in AlxGa1-xAs

In this paper we summarize our recent studies of the effects of local alloy disorder on the properties ofDX levels. A single emission rate is observed in GaAs where all Si-donors have identical local environments. In contrast, three discrete emission rates are observed in dilute AlGaAs alloys, suggesting that the group IV donor moves towards the interstitial site, thereby “selecting” three of the twelve surrounding group III atoms. We present evidence for an ordering of theDX levels consistent with Morgan’s model of a deepening potential well for theDX level as Al atoms are subsequently substituted for Ga atoms near the relaxed donor. These conclusions are consistent with earlier calculations of Chadi and Chang.     

On the deformation and fracture of porous materials

The constitutive behavior of porous materials (including the yield loci, the void growth rate, the macro stress-strain relation and the strain to localization instability) is examined based on the lower bound approach proposed by the present authors. These results are then compared with the experimental and the finite element results as well as those predicted by Gurson's equations. Emphasis is placed on approaching the real behavior from the upper and the lower bound analysis. Calculation is also made on the influence of void nucleation on the critical strain to instability and a modified strain-controlled nucleation criterion is proposed. Finally the instability and fracture of AISI4340 steel in plane strain tension is examined and comparison is made between theoretical and experimental results.     

低噪音摩阻复台材料影响因素的探讨

采用动态粘弹谱仪（ＤＤＶ）、电子扫描显微镜（ＳＥＭ）和摩擦试验机等对影响摩阻复合材料制动噪音的因素进行了探讨。结果表明，摩阻材料基体的合理改性以提高其损耗角正切ｔａｎδ对减少振动、降低噪音行之有效。同时对传统解决噪音的方法，如添加固体润滑剂、橡胶共混等进行了分析比较。     

A STUDY OF J-INTEGRAL OF THE ORTHOTROPIC COMPOSITE MATERIAL

ＡＳＴＵＤＹＯＦＪ－ＩＮＴＥＧＲＡＬＯＦＴＨＥＯＲＴＨＯＴＲＯＰＩＣＣＯＭＰＯＳＩＴＥＭＡＴＥＲＩＡＬＷａｎｇＡｉ－ｑｉｎ（王蔼勤）；ＦｅｎｇＢａｏ－ｌｉａｎ（冯宝莲）；ＹａｎｇＷｅｉ－ｙａｎｇ（杨维阳）（ＴａｉｙｕａｎＨｅａｖｙＭａｃｈｉｎｅｒｙ．...     

准分子激光的应用

本文介绍了准分子激光器的基本类型、主要应用领域及其与材料相互作用的机理。对准分子激光在电子工业、生物医学和材料加工方面的一些重要应用做了比较详细的论述。     

含微量元素铜焊锡丝的研制

在６０／４０的锡铅焊料中加入０．２％左右的铜，凝固后具有均匀细小的共晶组织，其熔点为１８３℃，焊点强度和扩展率均高于未加铜的６０／４０锡铅焊料，并且含铜的锡铅焊料在焊接时，对铜烙铁头和微细铜线了小的熔蚀性。