求解一类变形变分不等式的投影收缩算法及其性质

对一类变形的变分不等式：求，使得提出了一类投影收缩算法，并得到了该算法的收敛性及相关性质．     

Crystal structure and luminescence property of ternary terbium p-aminobenzoic acid complexes with different second ligands

Ternary terbium complexes with p-aminobenzoic acid (HL), [TbL₃(DMSO)(H₂O)]₂ (1), [TbL₃(DMF)(H₂O)]₂ (2) and [TbL₃(Bpy)(H₂O)]₂·2H₂O (3) (DMSO=dimethyl sulfoxide, DMF=N, N- dimethylformamide, Bpy=2, 2′- bipyridyl) have been synthesized, and their crystal structures determined. The luminescence properties of these complexes, including both the emission quantum yield and the fluorescence lifetime, have been investigated. The effect of a second ligand on the crystal structure and luminescence property of the ternary terbium p-aminobenzoic acid complexes, and the relationship between luminescence properties and crystal structure, including coordination mode of the L⁻ ligand and the characteristics of a second ligand, are discussed.     

Preparation of polymer/silica hybrid hard coatings with enhanced hydrophobicity on plastic substrates

In this study, an easy method to increase hydrophobicity of the polymer/silica hybrid coating was demonstrated. UV-curable nano-sized colloidal silica was synthesized and surface-modified both by a coupling agent, 3-(trimethoxysilyl)propyl methacrylate (MSMA), and a capping agent, trimethyethoxysiliane (TMES). The formed particles were introduced into the poly(2-hydroxyethyl methacrylate) (PHEMA) matrix to yield PHEMA/silica hybrid hard coatings on plastic substrates via a UV-curing process. Differential scanning calorimetric (DSC) analyses of the hybrids indicated increases of the glass transition temperature (T_g) with increasing silica content in the hybrids; in general, an increase of 23 °C could be achieved for hybrids doped with 15 wt.% silica. Thermal decomposition temperature (T_d), as measured by the thermal gravimetric analyzer (TGA), was found to depend on the silica content in a trend similar to that on T_g. Specifically, a large increase of 25 °C was observed when the sample contained 15 wt.% silica. The pencil hardness of the PHEMA/silica hybrids coated on poly(methyl methacrylate) (PMMA) substrates can reach 5H, in comparison with 2H for pure PHEMA coating. Abrasion resistance was enhanced when silica nanoparticles were incorporated. Furthermore, due to the incorporation of TMES, hydrophobicity of the hybrid coating increased considerably as the TMES content was increased. In the extreme case, a hard surface with a water contact angle (92°) has been obtained.     

转动相对论Birkhoff约束系统积分不变量的构造

研究转动相对论Birkhoff约束系统积分不变量的构造首先,建立转动相对论系统的约束Birkhoff方程;其次,利用等时变分与非等时变分之间的关系建立系统的非等时变分方程;然后,研究转动相对论Birkhoff约束系统的第一积分与积分不变量之间的关系,证明由系统的一个第一积分可以构造一个积分不变量,并给出自由Birkhoff系统的相应结果;最后,讨论转动相对论Hamilton系统、相对论Birkhoff系统和Hamilton系统、经典转动系统和等时变分情形下的积分不变量的构造,结果表明相关的结论均为该定理的特款给出一个例子说明结果的应用 关键词： 转动相对论 Birkhoff系统 约束 第一积分 积分不变量     

旋转超导体中的电流与电磁场

采用半经典理论方法,对旋转超导体内的电流和电磁场进行理论分析.在把非惯性力场等效为真实力场并假设其适用于量子力学的基础上,获得超导电子所满足的薛定谔方程和概率密度流表达式.发现超导电子的正则动量和空间相位的梯度有正比例的关系;发现在没有外电场和外磁场情况下,匀速转动的超导体内出现净电荷电场、磁场,表面出现净电荷及超导电流 关键词： 旋转超导体 超导电流 磁场 半经典理论     

Cymbal piezoelectric composite underwater acoustic transducer

The working principle of Cymbal piezoelectric composite underwater acoustic transducer was studied in this paper. PZT-5A piezoelectric ceramic disk was used as piezoelectric phase and brass foil was used as end cap electrode of the Cymbal transducer. The silicon rubber was used as the insulated proof layer of the underwater acoustic transducer. The properties of this transducer used as hydrophone, such as operation frequency, free-field voltage receiving sensitivity and directivity, were investigated. Several kinds of prototype of this transducer were fabricated and the properties of this transducer used as hydrophone were tested. The results show that the properties of this transducer used as hydrophone depend on the dimensions of Cymbal transducer because the piezoelectric properties of this transducer are dependent on the dimensions of Cymbal transducer's end caps. The appropriate dimensions for getting higher free-field voltage receiving sensitivity with -184.7 dB were obtained.     

Iterative methods for stabilized discrete convection-diffusion problems

In this paper we study the computational cost of solving theconvection-diffusion equation using various discretization strategiesand iteration solution algorithms. The choice of discretizationinfluences the properties of the discrete solution and alsothe choice of solution algorithm. The discretizations consideredhere are stabilized low-order finite element schemes using streamlinediffusion, crosswind diffusion and shock-capturing. The latter,shock-capturing discretizations lead to nonlinear algebraicsystems and require nonlinear algorithms. We compare variouspreconditioned Krylov subspace methods including Newton-Krylovmethods for nonlinear problems, as well as several preconditionersbased on relaxation and incomplete factorization. We find thatalthough enhanced stabilization based on shock-capturing requiresfewer degrees of freedom than linear stabilizations to achievecomparable accuracy, the nonlinear algebraic systems are morecostly to solve than those derived from a judicious combinationof streamline diffusion and crosswind diffusion. Solution algorithmsbased on GMRES with incomplete block-matrix factorization preconditioningare robust and efficient.