10,12—双炔廿三酸盐的LB膜特性研究

本文合成了10,12-双炔廿三酸,并用其在Si、SiO_2、CaF_2等基片上沉积了LB膜,结果表明,10,12-双炔廿三酸的镉盐成膜更稳定。这种LB膜在紫外光辐照下很快聚合,聚合前后的紫外-可见吸收光谱发生规律性的变化,并保持层状结构,等同周期稍变。通过红外吸收的二向色性分析,确定了该分子的取向。     

Equal quality distribution of gas–liquid two-phase flow by partial separation method

This paper proposes a new method for equal quality distribution of gas–liquid two-phase flow by partial separate-phase distribution with a dual-header distributor. The upper and liquid (lower) headers are interconnected with five vertical downward arms. A gas–liquid two-phase mixture enters the distributor from the upper header where most of the liquid of the mixture is removed through the downward arms into the liquid header. Hence, firstly, the remaining gas-rich fluid can be uniformly distributed into the outlet branches, and then secondly, the liquid collected in the liquid header can be uniformly re-distributed into the individual outlet branches. Because both distribution processes are conducted in the condition of single or near single-phase flow, mal-distribution of the two-phase flow is essentially eliminated, and a satisfactory equal quality distribution of gas–liquid two-phase flow is reached. Experiments were conducted in an air–water two-phase flow test loop. The inner diameter of the inlet pipe was 60 mm, the superficial velocity ranges of gas and liquid were 3–32 m/s and 0.02–0.17 m/s respectively, and the quality ranged from 0.02 to 0.44. The flow pattern in the inlet pipe included stratified flow, wavy stratified, slug flow, and annular flow. The experimental results showed that this new method could significantly improve the distribution performance of the two-phase flow. The maximum quality deviation between each outlet branch and the inlet pipe is less than ±1% under the conditions of stratified, wavy stratified and slug flows in the upper header, and less than ±5% in annular flow.     

Mechanical Behavior of Bulk Poly(Ethylene Terephthalate) Subjected to Simple Shear

Abstract

Mechanical behavior of bulk semicrystalline poly(ethylene terephthalate) (PET) processed through simple shear is investigated. The equal channel angular extrusion (ECAE) process was used to achieve the simple shear condition. The PET samples were processed in one and two ECAE passes in the same direction, with the sample rotated 180° about the extrusion axis for the second pass. Microstructural features at the nanometer and micrometer scales were studied by small‐angle x‐ray scattering (SAXS) and scanning electron microscopy (SEM). SAXS results showed that at the nanometer scale, two types of lamellar orientations are induced in both samples, but with different extents of orientation. In the ECAE‐oriented PET structures on the micrometer scale, as revealed by SEM, are well‐defined macrofibrils. However, the fibrillar structures in the sample extruded once are more oriented than those in the sample extruded twice. Fractography investigations suggest that the ECAE‐induced fibrillar structure and stretched amorphous chains are responsible for the change in mechanical properties.     

Modeling texture evolution in equal channel angular extrusion using crystal plasticity finite element models

A new approach to modeling crystallographic texture evolution in Equal Channel Angular Extrusion (ECAE) is presented in this paper. The proposed approach utilizes an elastic–viscoplastic single crystal constitutive model implemented in a finite element framework. A representative volume element of the polycrystal is subjected to boundary conditions that simulate the approximate deformation history experienced by different regions of the sample (at different through-thickness depths) in both Route A and Route C processing. The proposed approach aims to capture the influence of the complex interactions that ensue among the constituent individual crystals of a polycrystal in controlling the texture evolution in the sample, while capturing the boundary conditions inherent to ECAE deformation. The predictions from the proposed approach are compared against previously reported experimental measurements in ECAE of copper. It is observed that the proposed approach provides significantly better agreement with the measurements when compared against previously reported model predictions.     

Exact Solutions of Klein-Gordon Equation with Exponential Scalar and Vector Potentials

We obtain the exact analytical solution of the Klein-Gordon equation for the exponential vector and scalar potentials by using the asymptotic iteration method. For the scalar potential greater than the vector potential case, the exact bound state energy eigenvalues and corresponding eigenfunctions are presented. The bound state eigenfunction solutions are obtained in terms of the confluent hypergeometric functions.     

关于离子选择性电极分析中的等电位差－标准加入法的探讨

本文提出了一种新的离子选择性电极分析方法，即等电位差－标准加入法。本方法已用于氟的测定。进行了理论数据验证及误差分析，标准溶液的回收率为９６．６％－１０４．３％。本方法的影响因素少、准确度好、操作及计算简便。     

Sequencing games with repeated players

Two classes of one machine sequencing situations are considered in which each job corresponds to exactly one player but a player may have more than one job to be processed, so called RP(repeated player) sequencing situations. In max-RP sequencing situations it is assumed that each player’s cost function is linear with respect to the maximum completion time of his jobs, whereas in min-RP sequencing situations the cost functions are linear with respect to the minimum completion times. For both classes, following explicit procedures to go from the initial processing order to an optimal order for the coalition of all players, equal gain splitting rules are defined. It is shown that these rules lead to core elements of the associated RP sequencing games. Moreover, it is seen that min-RP sequencing games are convex. We thank two referees for their valuable suggestions for improvement. Financial support for P. Calleja has been given by the Ministerio de Educación y Ciencia and FEDER under grant SEJ2005-02443/ECON, and by the Generalitat de Catalunya through a BE grant from AGAUR and grant 2005SGR00984.     

Pointwise versus equal (quasi-normal) convergence via ideals

We prove a characterization showing when the ideal pointwise convergence does not imply the ideal equal (aka quasi-normal) convergence. The characterization is expressed in terms of a cardinal coefficient related to the bounding number b$\mathfrak{b}$. We also prove a characterization showing when the ideal equal limit is unique.