纳米金属颗粒膜的二次谐波增强效应

纳米尺寸金属颗粒膜可以产生较大的表面二次谐波增强。本文测量了用溅射法制备的钠米尺寸Ａｕ颗粒的反射二次谐波，其增强因子可达１０２数量级，理论计算了局域场因子与波长的关系曲线。对于用Ｎｄ：ＹＡＧ激光器输出的１．０６μｍ波长的基频光，可以获得较强的倍频光的局域场增强，对金属颗粒尺寸对局域场因子的影响进行了计算和分析。     

颗粒物质中的奇异现象

通过分析颗粒物质中一些有别于气体、液体和固体的奇异现象,结合生活和生产中的实际例子进一步认识颗粒物质的一些基本特性、规律、有待解决的问题及研究意义.     

Sound field of a baffled sound source covered by an anisotropic rigid-porous material

A theoretical approach for the sound field of a piston sound source covered by a finite thickness layer of anisotropic rigid-porous material is presented. The formulation is an extension of the method worked out by Amedin et al. [Sound field of a baffled piston source covered by a porous medium layer. J Acoust Soc Am 1995;98(3):1757]. First, in the present study the sound field of a point source is described by cylindrical waves. Then, with the proper boundary conditions, the sound pressure radiated from a piston source covered by a layer of anisotropic porous material can be calculated. The effects of frequency and bulk density of material on the sound propagation in an anisotropic porous material are studied. Finally, the effect of anisotropy is discussed.     

红外光谱仪在红外电磁波吸收材料研究中的应用

以Lambere-Beer定律为基础．根据傅里叶变换红外光谱仪的特点，提出了红外电磁波吸收材料吸波性能的测试方法，并对非晶态SiO2粉末材料的红外电磁波吸收特性进行了讨论．实验结果表明。该方法简便、快速、可操作性强．     

Classical simulations of magnetic structures for chromium clusters: Size effects

Classical (Heisenberg) simulations show that the total magnetization of the lowest-energy states of clusters made of antiferromagnetically coupled chromium atoms is planar, rather than collinear, depending on the arrangement of the atoms. Although the model Hamiltonian is not restrictive, many cluster configurations of various numbers of atoms do not use all three directions for the spins. This result confirms the conclusion drawn from the local-spin DFT calculation by Kohl and Bertsch that clusters of N≤13 have non-collinear magnetic moments. The present simulations show non-collinear spin ordering also for bigger clusters, designed to be as spherical as possible following the bcc arrangement, when atoms interact both with the nearest and next-nearest neighbours. Depending on the signs of the coupling constants frustration appears. The advantage of the discrete model, despite the simplicity, is that very large clusters and magnetization at finite temperatures can be studied. This model predicts that clusters with specific numbers of atoms interacting only with the nearest neighbours have collinear spins as in the bulk. We also apply the model to simulate the destruction of the anti-ferromagnetic ordering by thermal fluctuations. This model shows no unique magnetization of mixed Fe _0.33 Cr _0.67, which is consistent with experimental observations.     

红柱石材料领域的应用及其研究新进展

本文对目前红柱石材料的基本性质、资源分布状况、红柱石的选矿工艺以及开发应用状况做了介绍,并重点阐述了红柱石材料领域的研究新进展和趋势,特别是红柱石用做矿物材料的研究现状,以及开发利用的前景.     

偶氮基染料掺杂薄膜的双光子图象存储

研究了偶氮基染料掺杂薄膜ＭＯ－ＰＶＡ和ＥＯ－ＰＶＡ的双光子存储特性。在对薄膜用Ａｒ＾＋激光作预激发下实现了Ｈｅ－Ｎｅ激光的红光存储。获得了实时和短时存储照片。光电记录存储曲线，分析了双光四能级系统的存储机制。实现确定了最佳预激发功率约为０．２８Ｗ／ｃｍ＾２，最小Ｈｅ－Ｎｅ光可存储功率密度低于０．２Ｗ／ｃｍ＾２。     

含压电片梁的静变形控制

首先借助阶梯函数，建立了含有任意分布的用作执行器的压电片的梁挠曲轴线方程。然后利用该方程，进行了梁的静变形控制的研究。最后结合实例，用“遗传＋配点”法对压电片的位置和尺寸进行了优化。结果表明，本文建立的挠曲方程形式简洁，求解简单：“遗传＋配点”法优化效果明显。     

机械合金化合成CoSb3过程中的固相反应机理的热力学解释

用Co和Sb作为初始原料，通过机械合金化(mechanical alloying, MA)的方法合成了CoSb₃,并系统研究了MA转速和MA时间对MA过程中固相反应的影响.XRD结果表明，相同MA转速下，CoSb₃的量随MA时间的延长而增多，但是MA时间过长会导致大量CoSb₂的生成，甚至诱发CoSb₃分解为CoSb₂和非晶态Sb.而提高MA转速，只能缩短固相反应的发生时间，而不会改变整个固相反应 关键词： 机械合金化 热电材料 3')" href="#">CoSb₃ 非平衡热力学     

Solving material nonlinear structural problems by a finite analytic method in local coordinates

The purpose of this paper is to develop a finite analytic (FA) numerical solution for the elasto-plastic problem of the total theory. Schemes for the FA method in local coordinates for solving non-linear governing equations in the form of Navier equations are derived, which can be utilized to solve the problem in a domain of arbitrary geometry. Numerical illustration shows that the schemes are effective and practical.