羟基氧化镍的制备及应用

综述了羟基氧化镍(NiOOH)制备方法的研究进展及其应用情况.阐述了羟基氧化镍晶体结构,不稳定性与其制备方法的关系,重点介绍了化学氧化法和电解氧化法两种制备羟基氧化镍的方法,比较分析了两种制备方法的优缺点,并提出了电解-化学氧化制备羟基氧化镍的新思路,简要评述了今后羟基氧化镍制备方法的研究方向.     

分离用无机膜的制备方法及研究展望

无机膜的制备技术已得到广泛的研究,报道了许多制备方法,综合论述了无机膜的制备方法及当今主要研究热点即膜材料、膜制备等,并列举了无机膜在许多领域的应用,最后预测了无机膜制备研究的发展趋势.     

超细SiC片晶的制备方法

超细SiC片晶由于其高强度、高弹性模量和高导热系数已成为替代价值昂贵、制备技术复杂的SiC晶须的理想的增韧材料SiC片晶的制备方法有化学制备法和机械制备法。本文中详细介绍了用机械方法制备SiC片晶的设备与工艺过程,阐述了各种制备方法的工作原理及其优缺点,通过对各种制备方法的比较得出采用气流磨与分级机结合工艺是目前制备系列超细SiC片晶有效的和最经济的生产工艺。     

超细TiC粉体制备的研究现状及展望

较系统地综述了目前TiC超细粉(尤其是纳米及亚微米TiC粉)的各种制备方法,对不同的制备方法进行了比较,着重分析了各制备方法的技术关键和优缺点,最后对超细粉TiC制备的进一步发展进行了展望.分析认为利用化学方法进行混料,结合快速均匀加热进行合成,是未来超细TiC粉工业化制备的发展方向.     

制备方法对石墨烯电化学性能的影响

石墨烯处于当今电化学纳米材料研究的前沿,因制备方法多种多样,得到的石墨烯材料性能也存在相当大差异。综述了通过目前流行的制备方法获得的石墨烯的电化学性能研究成果,分析了制备方法间、制备条件间的不同对石墨烯电化学性能的影响。     

国内铁氧化物的研究现状

在大量阅读国内外有关铁氧化物文献的基础上,综述了国内铁氧化物制备的不同方法,包括沉淀法制备铁氧化物、水解法制备铁氧化物、特殊方法制备铁氧化物、纺锤形铁氧化物的制备、掺杂离子制备去铁氧化物、FeOOH的热处理、FeOOH制备的动力学研究等.指出国内以氧化Fe(OH)2制备FeOOH,然后转化为Fe2O3的方法对于制备均匀单分散的胶体粒子有先天不足,其制备过程复杂,容易受制备条件影响.     

空心/多孔微球制备技术研究进展

综述了聚合物多孔微球和空心微球的制备方法及其相应的成孔机理。空心微球的制备以模板法为主,而多孔微球的制备则以种子溶胀法和致孔剂法为主。这些方法各有优缺点,根据材料的用途选择相应的制备方法,才能得到性能理想的中空或多孔微球。同时,讨论了多孔微球和空心微球制备中存在的问题及制备方法的选择。     

共品陶瓷制备方法研究进展

针对国内共晶陶瓷及其制备方法的研究较少,对国内外现阶段该共晶复合陶瓷制备方法作一一介绍,并简要介绍了Al2O3基共晶陶瓷制备方法再国内的研究进展,以期引起国内学者对共晶陶瓷制备方法的关注和兴趣。     

稀土氧化物纳米材料制备的研究进展

稀土氧化物纳米材料的合成与制备近年来已成为国内外学者研究的一个热点。本文介绍了国内外稀土氧化物纳米材料制备及合成方法的研究进展,并对稀土氧化物纳米材料的制备方法进行了分类。同时,综合比较了各自的优点和缺点,并对各种制备方法在各个领域的应用前景进行了一定的展望。     

纳米储氢合金制备方法的研究进展

纳米储氢合金的热力学与动力学性能明显超过了相应的微米级合金 ,引起了储氢合金研究者的关注 ,而目前纳米储氢合金的制备方法仅集中于球磨法。本文总结了纳米储氢合金颗粒与复合材料的制备方法 ;并从纳米材料制备技术的角度 ,对潜在的纳米储氢合金的制备方法进行了评述     

TWO ALGORITHMS FOR GLOBAL OPTIMIZATION OF GENERAL NLP PROBLEMS

After a brief overview of the methods from the literature, two new algorithms (zooming and domain elimination) for global optimization of general NLP problems are introduced. Operations analysis and stopping criteria for the methods are discussed. Numerical evaluation of the methods is carried out using a set of mathematical programming test problems. Performance of the methods is compared with the Controlled Random Search (CRS) and the Simulated Annealing (SA) methods. The methods are superior to SA for the test problems, as they are more robust, efficient and accurate. The CRS is more efficient than the new methods; however, it is applicable to unconstrained problems only. Therefore, it is concluded that the new methods are useful for engineering optimization applications.     

基于合成孔径雷达图像内波参数反演方法

总结了目前已有的通过合成孔径雷达图像反演内波参数的方法,并按照内波深度、波速、特征宽度以及振幅的分类对不同的方法进行了描述.将各种参数反演方法应用于合成孔径雷达图像,对内波反演结果与同一区域的实测数据进行了比较.首次对同一内波参数的不同反演方法进行对比,并对各参数反演方法的适用条件进行了讨论.     

多源图像配准技术分析与展望

在给出多源图像配准的定义后,将常见的图像配准方法分为基于图像灰度的方法和基于图像特征的方法两大类。以此为分类基础,对国内外现有的图像配准技术和方法进行了分析和评述,并重点介绍了基于图像特征的配准方法。随后对图像配准技术所面临的主要难题作了分析。最后介绍了图像配准在军事、遥感、医学等领域的应用,并展望了其未来的发展。     

基于θ方法的波形松弛方法的A稳定

描述芯片或电力系统运行规律的常用数学模型是高维微分代数方程组，其中的微分方程组太大，线性多步法和Runge-Kutta法等经典数值方法均不能有效求解。为求解这些微分方程组，借鉴常微分方程经典数值方法的A稳定定义，提出了波形松弛方法A稳定(强A稳定)，给出了基于θ方法的波形松弛方法 A稳定(强A稳定)和非A稳定的条件，以及几个支持理论结果的数值算例。研究结果表明WR方法并非天然继承底层方法的A稳定性，为使波形松弛方法 A稳定，需要使用A稳定的底层方法和适当的分裂函数，这为刚性方程WR方法的构造奠定了理论基础。此外，借鉴经典数值方法的B稳定定义，提出了波形松弛方法的B稳定(强B稳定)，给出了波形松弛方法强B稳定的条件。     

Modern Domain-based Discretization Methods for Damage and Fracture

Standard domain-based discretization methods that have been developed for continuous media are not well suited for treating propagating (or evolving) discontinuities. Indeed, they are approximation methods for the solution of partial differential equations, which are valid on a domain. Discontinuities divide this domain into two or more parts. Conventionally, special interface elements methods are placed a priori between the continuum finite elements to capture discontinuities at locations where they are expected to emerge. More recently, discretization methods have been proposed, which are more flexible than standard finite element methods, while having the potential to capture propagating discontinuities in a robust, efficient and accurate manner. Examples are meshfree methods, finite element methods that exploit the partition-of-unity property of finite element shape functions, and discontinuous Galerkin methods. In this contribution, we shall present an overview of these novel discretization techniques for capturing propagating discontinuities, including a comparison of their similarities and differences.     

Radial basis function approximation methods with extended precision floating point arithmetic

Radial basis function (RBF) methods that employ infinitely differentiable basis functions featuring a shape parameter are theoretically spectrally accurate methods for scattered data interpolation and for solving partial differential equations. It is also theoretically known that RBF methods are most accurate when the linear systems associated with the methods are extremely ill-conditioned. This often prevents the RBF methods from realizing spectral accuracy in applications. In this work we examine how extended precision floating point arithmetic can be used to improve the accuracy of RBF methods in an efficient manner. RBF methods using extended precision are compared to algorithms that evaluate RBF methods by bypassing the solution of the ill-conditioned linear systems.     

A0 – Stable family of single step methods for semidiscretized parabolic problems

A general family of single-step methods for use in first-order ODEs is presented. This family of methods, called SS3-methods, embraces generalized trapezoidal methods, SS21-methods, α-methods and many other well-known methods, thus providing a good basis for comparison of these methods. Corresponding parameter values of SS3 methods for these methods are presented. The analysis of SS3-methods is restricted to linear and symmetric systems. Stability, convergence, accuracy, numerical dissipation and overshoot of the methods are considered. The conditions for algorithm parameters to exhibit good characteristics in these respects are given. It is shown that the optimal subfamily of SS3-methods coincides with α-methods.     

Comparison of regularization methods for solving the Cauchy problem associated with the Helmholtz equation

In this paper, several boundary element regularization methods, such as iterative, conjugate gradient, Tikhonov regularization and singular value decomposition methods, for solving the Cauchy problem associated to the Helmholtz equation are developed and compared. Regularizing stopping criteria are developed and the convergence, as well as the stability, of the numerical methods proposed are analysed. The Cauchy problem for the Helmholtz equation can be regularized by various methods, such as the general regularization methods presented in this paper, but more accurate results are obtained by classical methods, such as the singular value decomposition and the Tikhonov regularization methods. Copyright © 2004 John Wiley & Sons, Ltd.     

直流电阻数字化检测方法

介绍了直流电阻的三种数字化检测方法;对三种方法进行分析并给出了测量结果的不确定度;给出了直流电阻检测中可选择的方法.     

P－S－N曲线测定法比较研究

本文介绍了七种测定Ｐ－Ｓ－Ｎ曲线的方法。并且用五种材料的实验数据对上述测定方法作了分析比较。在比较了几种方法的优缺点的基础上，提出了选择试验方法的建议和结论。