注塑模冷却分析的边界元法

本文介绍了一种注塑模冷却分析的有效方法－－边界元法，根据注塑模内部尺寸相差悬殊（型胶为一狭缝，冷却孔长度远大于其直径）的结构特点，推导出适用于注塑模冷却分析折边界积分方程，并给出模具三维温度场的边界元计算方法，最后，利用一个例子说明了其于边界元法的冷却分析在实际中的应用。     

图像分析技术在聚合物/粘土纳米复合材料微观结构形态研究中的应用

基于MATLAB图形及影像处理技术，开发了适用于处理聚合物／粘土纳米复合材料（PCN）微观结构形态的应用程序。应用程序包含边界探测和颗粒尺寸分析两个子程序，具有探测孤立颗粒边界和计算颗粒尺寸功能。应用该程度分析了聚丙烯／蒙脱土（PP／MMT）纳米复合材料初级结构的TEM照片，得到蒙脱土片层在PP基体中的微观结构形态和尺寸分布。结果表明：该图像分析技术能够快速有效地确定PCN的TEM照片中粘土片层的形状和尺寸。此外，该图像分析技术还可以用于共混物形态的研究。     

信息与动态

<正>发酵酒精和白酒工业水污染物排放标准(GB 27631—2011 2012-01-01实施)本标准规定了发酵酒精和白酒工业企业或生产设施水污染物排放限值、监测和监控要求,以及标准的实施与监督等相关规定。本标准规定的水污染物排放控制要求适用于企业直接或间接向其法定边界外排放水污染物的行为。本标准适用于     

热传导问题的SPH方法及其边界处理

本文将光滑粒子流体动力学（Smooth Particle Hydrodynamics,SPH）方法应用于热传导问题中,通过二阶导的SPH方法求解热传导离散方程。分别采用了镜像粒子法和固定边界粒子法处理SPH方法的边界条件,提高了计算精度;并对不同核函数和不规则边界的热传导问题进行数值模拟,结果表明,二阶导的SPH方法适用于求解热传导问题,并能达到较高的精度和稳定性。     

橡胶制品工业污染物排放标准

本标准规定了橡胶制品工业企业或生产设施水污染物和大气污染物的排放限值、监测和监控要求,以及标准实施与监督等相关规定。本标准规定的水污染物排放控制要求适用于企业直接或间接向其法定边界外排放水污染物的行为。     

KEBA公司：全面优化注塑机性能的控制解决方案

在Chinaplas 2011展会中，作为塑料机械优化控制解决方案的一流供应商，奥地利KEBA公司重点展示了注塑机优化控制平台——KePlast系列。该系列包括KePlast i1000、KePlasti2000及KePlasti5000三种系统，其中，KePlasti1000适用于标准的液压注塑机，后两种既适用于液压注塑机，也适用于全电动注塑机，它们都适用于多组件机械手。     

发酵酒精和白酒工业水污染物排放标准

（GB 27631—2011 2012-01-01实施）本标准规定了发酵酒精和白酒工业企业或生产设施水污染物排放限值、监测和监控要求,以及标准的实施与监督等相关规定。本标准规定的水污染物排放控制要求适用于企业直接或间接向其法定边界外排放水污染物的行为。     

活性和高熔点金属在硫酸中的应用

评述了活性金属(锆和钛)和高熔点金属(铌和钽)在一定温度和浓度硫酸中的耐蚀性。钛只适用于低浓度；铌适用于常压沸点以下的大部分浓度范围；钽适用于常压沸点及沸点以上的整个浓度范围；Ta40Nb合金几乎适用于所有浓度，但适用温度略低于钽而高于铌；锆适用于常压沸点及沸点以上的w(H2S04)70％硫酸。在选择适用于硫酸的最佳金属时，必须考虑操作条件，以及设备生命周期维修费用和停车费用。设计者亦必须充分考虑温度、浓度及杂质含量偏移的可能性，因为它们对金属的耐蚀性可能会有负面影响。据此建议采用活性或高熔点金属。     

高效低泡浆纱柔软剂的研究

该文介绍了高效低泡浆纱柔软剂实验工艺，。指该柔软剂为一种复合型柔软剂，特别适用于涤／棉混纺纱上浆，也适用于纯棉纱上浆。     

《橡胶制品工业污染物排放标准》实施

由环保部发布的《橡胶制品工业污染物排放标准》（GB27632—2011）于2012年1月1日起正式实施。该标准为首次发布。标准规定了橡胶制品工业企业或生产设施水污染物和大气污染物的排放限值、监测和监控要求,以及标准实施与监督等相关规定。标准规定的水污染物排放控制要求适用于企业直接或间接向其法定边界外排放水污染物的行为。     

Flaw Distributions and the Variation of Glass Strength with Dimensions of the Sample

The phenomena associated with the fracture of glass are more logically expressed by a distribution function giving the probability of failure when the tensile stress at a point reaches a given value than by the concept of an intrinsic strength which is a characteristic of the material. In practice it is found that this distribution function has appreciable values only on the surface of glass. Functional equations are developed relating the results to be expected in tension tests and in modulus of rupture tests with one or two loading edges on cylindrical rods. Experiments with acid-polished rods of Pyrex-brand chemical glass require a two-term distribution function dn = (2.9 × 10⁻⁹S²+ 7.15 × 10⁻²¹.S⁸) dS to express the results found by a bending test with one loading edge (units, kilograms and millimeters), whereas results given by Bailey for lime-glass rods not polished are expressed by the function dn = 7.3 × 10–32 (units, pounds and inches) for tests with two loading edges.     

A single particle Hamiltonian for electro-magnetic properties of graphene nanoribbons

Graphene zigzag edges are known to show the spin polarized ferromagnetic states, which are well described by the mean field treatment of Hubbard model. The parameter of onsite Coulomb interaction U is estimated to be comparable to the kinetic hopping parameter t so as to fit the electronic band structures obtained by the spin–polarized density functional theory (DFT). In this paper, we propose a simple way to transfer the electronic band structures obtained by DFT onto the mean-field Hubbard Hamiltonian by adopting site-dependent U parameter, which is taken as the decaying function from the edge. This approach is applicable to both anti-ferromagnetic and ferromagnetic states between two edges of graphene nanoribbons and will serve to perform the further large-scale simulation of electro-magnetic transport properties of graphene-based nanodevices.     

Analysis of EXAFS data on bimetallic clusters

In previous studies of the structures of bimetallic clusters using extended X-ray absorption fine structure (EXAFS), structural parameters were determined by fitting the single scattering expression for EXAFS to experimental data associated with an absorption edge of each component. The data for the two edges were fitted separately. Recently, with an extensive modification of the computer program for the analysis of EXAFS data, it has been possible to fit the EXAFS data for the two edges simultaneously. This improved method of analysis has the feature thatall of the EXAFS data are used in the determination ofall of the structural parameters, and permits one to impose in a direct manner certain necessary physical conditions regarding the system. Consequently, one has greater confidence in the values obtained for the parameters. The present paper first summarizes published results obtained by the previous method of analysis on a number of systems. For comparison, a summary is then given of results obtained from the same data on these systems with the new method of analysis.     

Bending of Elastically Supported Axisymmetric Plates

In the bending of symmetrically loaded circular plates of brittle material, e.g. glass, which are supported between flexible gaskets at the periphery, large errors can result in estimating the stresses and deflections in the plate if it is assumed that the plate is simply supported. This paper uses the exact numerical solution, given elsewhere, in comparing the exact stresses and deflections with those obtained by assuming simply supported edges. It is shown that gasket width and stiffness are important in controlling the maximum stress. The deviation from an assumption of simple support is greatest when the plate is thin.     

Catalytic chemical vapor deposition of methane on graphite to produce graphene structures

Graphene structures, obtained by catalytic chemical vapor deposition of methane on highly oriented pyrolitic graphite (HOPG), were examined using scanning tunneling microscopy. Depending on the Fe catalyst coverage and localization on the substrate steps and terraces, different graphene structures were obtained: curved graphene sheets at the edges of topmost stacked graphene bilayers, laterally grown terraces at the edges of individual graphene layers parallel to the HOPG basal plane and planar graphene islands on the terraces. A growth mechanism is proposed that takes into account the specific features of the spatial distribution of Fe catalytic nanoparticles on the substrate surface, driven by metal film-substrate interaction. The present synthesis approach is promising for the controlled growth and modification of graphene layers, as well as for engineering the edge characteristics of graphene systems at the atomic scales.     

Granular-bed filtration assisted by filter-cake formation: 4. Advanced designs for panel-bed filtration and gas treating

“Historic” panel bed filter louvers slope upward toward their outer edges. Improved louver designs exploit the discovery that puffback renewal of gas-entry sand faces is more effective if louvers slope downward toward outer edges. For given panel bed height, down-sloping louvers present larger total gas-entry sand face, affording equipment that occupies smaller ground area for given filtering capacity. As well, for down-sloping louver designs, other means can create a gas-entry-face renewing body movement, viz., a sharp motion (either, as appropriate, sideways, downward, or upward) such as may be effected by the blow of a hammer. Newly conceived arrangements of flat-plate louvers are particularly attractive relative to historic louvers: resembling subway gratings, they cost less, and are better suited for use in a panel bed that provides for countercurrent contacting of gas and powder.Also reported is a new “panel filter” comprising downwardly sloping “filter trays” mounted one above another, each tray displaying a gas-entry-face renewable either by puffback or hammer blow. For filtering a given flow of gas, a panel of filter trays can occupy smaller ground area than louvered beds, can be assembled from fewer elements, and can afford a lower pressure drop.     

复合材料层合结构自由边效应实验研究

复合材料层合结构的自由边效应是复合材料结构总体破坏的主要因素之一.本文对复合材料层合结构自由边效应进行了实验研究,得到了自由边效应的分布规律,即层间应力在自由边界和载荷边界附近有明显的应力集中,在离开边界的地方应力集中现象很快消失.实验结果与数值模拟结果趋势基本一致,这一规律的发现可为复合材料制造工艺和工程应用提供指导.     

A two-dimensional stress analysis of single-lap adhesive joints of dissimilar adherends subjected to tensile loads

Single-lap adhesive joints of dissimilar adherends subjected to tensile loads are analyzed as a three-body contact problem using the two-dimensional theory of elasticity. In the numerical calculations, the effects of Young's modulus ratio between different adherends, the ratio of the adherend thicknesses, the ratio of the adherend lengths, and the adhesive thickness on the contact stress distributions at the interfaces are examined. As a result, it is found that (1) the stress singularity occurs near the edges of the interfaces and it increases at the edge of the interface of an adherend with smaller Young's modulus; (2) the stress singularity increases at the edge of the interface of an adherend with thinner thickness; (3) the singular stresses increase at the edges of the two interfaces as the ratio of the upper adherend length to the lower one decreases; and (4) the singular stresses increase at the edges of the two interfaces as the adhesive thickness decreases when the adhesive is thin enough, and they also increase as the adhesive thickness increases when the adhesive is thick enough. In addition, the singular stresses obtained from the present analysis are compared with those obtained by Bogy. Fairly good agreement is seen between the present analysis and the results from Bogy. Strain measurement and finite element analysis (FEA) were carried out. The analytical results are in fairly good agreement with the measured and the FEA results.     

环已二醇二丙烯酸酯的合成工艺

用浓硫酸作催化剂 ,环已烷作带水剂 ,对甲氧基苯酚作阻聚剂 ,利用直接酯化法合成环已二醇二丙烯酸酯 ,同时就助剂作用和用量对反应影响进行探讨 ,确定了合适的合成工艺路线。     

Optimal control of a stirred-tank reactor with rapidly-decaying catalyst

The singular perturbation solution to a general optimal control problem consisting of the optimization of a final-time function of the “slow” variables, subject to inequality control constraints in the inner control region, and a free-time terminal manifold for the fast-slow differential equations, is given. The example studied here is the optimal temperature control of a stirred-tank catalytic reactor in which the time constant of the catalyst decay is appreciable compared to the mean residence time. The first-order corrections to the usual quasi-steady state (zeroth-order outer) solution, consisting of the zeroth-order inner solutions at both ends of the interval of operation and the first-order outer solutions, are calculated. Boundary layers thus appear at start-up and shutdown. The second-order corrections can be calculated by the methods given here, and would entail interior boundary layers around the entry points to the control constraints. These entry points are not fixed in time, and a time-scaling procedure, developed previously for converting free-time to fixed-time problems, is employed. The solutions are thus matched at the edges of the boundary layers, and around the inequality-constraint entry and exit points. Some numerical solutions are given which show an appreciable increase in return on investment over the QSS solution.