Electronic energy-density effects in ion tracks of metals

High resolution Auger-electron spectroscopy has been applied to the interaction of swift heavy ions with atomically clean metallic solids. Spectra have been taken for fast projectile electrons and for charge-state equilibrated ions at normal incidence on microcrystalline beryllium samples, Al(1 0 0) single crystals and several metallic glasses (Al₈₇La₇Ni₅Zr₁, Ni₇₈B₁₄Si₈, Co₆₆Si₁₆B₁₂Fe₄Mo₂). From the energy shift and from the Auger-line width we have extracted ion-track potentials and also electron temperatures inside ion tracks. A first determination of the angular distribution of multiple-ionization lines is presented as well.     

中间夹层材料和保护气体对不锈钢-碳钢复合效果的影响

提出了利用中间夹层材料促进不锈钢与碳钢复合的新工艺。研究了中间夹层材料和保护气体对不锈钢与碳钢复合效果的影响规律。结果表明，采用自制的银基中间夹层材料可以使两种母材在较低的压力下实现良好的复合；加热过程中采用氩气保护能够有效地去除不锈钢表面致密的氧化膜。     

Starting solutions for some unsteady unidirectional flows of a second grade fluid

Exact solutions corresponding to the motions of a second grade fluid, due to the cosine and sine oscillations of an infinite flat plate as well as those induced by an oscillating pressure gradient are determined by means of the Fourier sine transforms. These solutions, presented as sum of the steady-state and transient solutions, satisfy both the governing equations and all associate initial and boundary conditions. In the special case when α₁ → 0, they reduce to those for a Navier-Stokes fluid.     

基于方向梯度局部方差的分层遥感图像融合

为了充分利用各种遥感图像的信息．本文对以往图像融合技术进行了简要的概述，分析了各种方法的优缺点．给出了一种新的基于方向梯度局部方差的金字塔图像融合方法。将各源图像进行金字塔分解，得到多分辨率描述．建立方向梯度金字塔．采用局部方差准则融合源图像的各分解层．再进行金字塔分解的逆变换，得到融合图像。此外．利用信息熵等准则和其他融合方法进行比较．实验结果表明用此方法能得到更好的融合效果。     

在线群体交互的影响模型及其学习算法

在线群体交互有助于数字图书馆发挥其服务人类需求的潜力，但如何量化在线群体交互对个人信息访问方面的影响还有待进一步研究．该文用隐Markov模型(HMM)来建模交互用户的状态序列及其相应的信息搜索行为，并基于影响模型理论提出了一个在线群体交互影响模型来分析用户在从数字图书馆选择资料和搜索所需信息时的相互影响．为满足本应用问题中增量模型学习的需要，文章还从耦合隐Markov模型(CHMM)学习算法引申出基于梯度的方法来进行在线群体交互影响模型参数的训练．实验结果显示，本文所提出的模型和算法能较准确地刻画在线群体交互对个人信息访问行动的影响．     

梯度投影法应用于冗余机器人分解运动速度控制的新新方案

本文讨论分解运动速度控制框架下将梯度投影法应用于冗余机器人控制的有关问题。     

NPB CG在分布式环境下的并行实现

ＣＧＢｅｎｃｈｍａｒｋ是ＮＡＳＰａｒａｌｅｌＢｅｎｃｈｍａｒｋｓ（ＮＰＢ）中的一个核心程序，它用共轭梯度法求大型稀疏对称正定矩阵的最小特征值，本文介绍其主要算法，并给出在分布式环境下的高效并行算法，最后给出了在ＳＧＩＣｈａｌｅｎｇｅＰＶＭ平台上的测试结果     

Spherical harmonic coefficients for the potential of a constant-density polyhedron

Recurrent relationships for the definitions of fully normalized spherical harmonic coefficients C?_n,m and S?_n,m are derived and integrated analytically to yield the gravitational potential of a constant-density polyhedron. The algorithm is expressed in a C language computer program.     

Nonlinear Inverse Boundary-Value Problems of Conformal Mapping with a Controlling Potential

Some characteristic cases of formation of an ideal flow are described depending on preset values of controlling potential. Based on the modified G. Polozhii's method of summary mappings, the characteristic function of the flow is obtained. Examples of construction of a dynamic grid, field of velocities, and formation of different flows are given. Types of key problems of finding the values of controlling potential, which provide optimization of definite functionals are defined. An example of solution to one of them is presented.     

Heat Transfer Analysis During "One-Step" Directional Solidification Process for Giant Magnetostrictive Materials

By theoretical analysis of heat transfer during the "one-step" directional solidification process, the functional relation between the temperature in solid-liquid interface and its effect factor was studied. The thermal gradient in solid liquid interface and heat transfer coefficient between the samples and surroundings were also calculated. On the basis of the above analysis, some suggestions for improving the thermal gradient in solid-liquid interface were put forward. It will provide a theoretical instruction for preparing high performance giant magnetostrictive materials (GMM).