Coupled field formulation of exactly integrated membrane finite elements insensitive to distortion

Abstract

An efficient 4-noded membrane element tolerant and insensitive to mesh distortion is developed using kinematically coupling the in-plane displacements which satisfy the equilibrium equations in Cartesian coordinates and results in material-dependent coupled field interpolation functions making the element free from volumetric and shear locking. The proposed formulation provides a preliminary concept for the satisfaction of natural boundary conditions which is used to satisfy the strong patch test. The proposed element, passed several benchmark problems from the literature, compared well with elasticity solutions, passed the weak patch test and the inf-sup test for both compressible and incompressible cases.     

气相色谱法测定调和油中18种脂肪酸

目的建立气相色谱法测定调和油中18种脂肪酸的方法。方法样品经过氢氧化钾甲醇溶液甲酯化,采用毛细管色谱柱(100 mm×0.25 mm, 0.2μm)和程序升温模式进行测定,检测器温度为280℃。结果 18种脂肪酸的线性关系良好(r>0.999),检出限为0.0005~0.009mg/kg,回收率为78.9%~99.1%,相对标准偏差(relative standard deviation, RSD)为0.768%~8.236%。结论该方法快速、简单、回收率和精密度良好,可用于调和油中脂肪酸的的检测。     

Designing amorphous formulations of polyphenols with naringin by spray-drying for enhanced solubility and permeability

Naringin (NAR), a major flavanone (FVA) glycoside, is a component of food mainly obtained from grapefruit. We used NAR as a food additive to improve the solubility and permeability of hydrophobic polyphenols used as supplements in the food industry. The spray-dried particles (SDPs) of NAR alone show an amorphous state with a glass transition temperature (T_g) at 93.2 °C. SDPs of hydrophobic polyphenols, such as flavone (FVO), quercetin (QCT), naringenin (NRG), and resveratrol (RVT) were prepared by adding varying amounts of NAR. All SDPs of hydrophobic polyphenols with added NAR were in an amorphous state with a single T_g, but SDPs of hydrophobic polyphenols without added NAR showed diffraction peaks derived from each crystal. The SDPs with NAR could keep an amorphous state after storage at a high humidity condition for one month, except for SDPs of RVT/NAR. SDPs with NAR enhanced the solubility of hydrophobic polyphenols, especially NRG solubility, which was enhanced more than 9 times compared to NRG crystal. The enhanced solubility resulted in the increased membrane permeability of NRG. The antioxidant effect of the hydrophobic NRG was also enhanced by the synergetic effect of NAR. The findings demonstrated that NAR could be used as a food additive to enhance the solubility and membrane permeability of hydrophobic polyphenols.     

利用迭代方法求解测量平差中的线性方程组

在测量平差中，各种观测量与已知条件以及各种图形几何条件之间可组成条件方程组或误差方程组，并可对方程组线性化。本讨论了迭代法求解条件平差和间接平差方程组的过程，最后形成了各算法的数学模型及相关的程序代码。     

论矿业工程中的流—固耦合渗流问题

简单回顾渗流力学发展历史，指出实际沙流都是在可变形多孔介质中发生的，流体流动与介质变形间存在相互作用。过去常加以忽略，将渗流作为非耦合问题研究，随着科学技术的发展．有越来越多的无法忽略耦合效应的工程问题．本文较系统地介绍了矿业工程中涉及的流-固耦合问题以及流-固耦合渗流的研究方法、宏观方程与测试技术和应用．     

抑制型离子色谱法测定隔夜沸水中常见阴离子的含量

介绍了用抑制型离子色谱法测定隔夜沸水中F-,Cl-,NO2-,H2PO4-,NO3-的含量的方法:流动相为4mmol/L Na2CO3与3mmol/L NaHCO3的混合溶液,流动相流速为1.5mL/min,进样量为0.5mL。5种阴离子在上述色谱条件下分离良好,检出限分别为0.005mg/L,0.01mg/L,0.04mg/L,0.08mg/L,0.06mg/L;用色谱软件绘制工作曲线,定量测定的线性相关系数均在0.995以上;样品回收率在99.6/～108/之间。     

金川二矿区围岩-充填体应力场的本构关系

本文结合金川二矿区充填机理研究工作的长期实践,应用粘弹塑性理论和增量计算方法,论述了围岩、矿体、充填体三者共同吻合变形作用的本构关系,较好地解决了金川二矿区一号矿体下向大面积胶结充填体和岩体共同作用时围岩的稳定性问题,计算结果与现场观测的围岩变形位移基本符合。为二矿区一号矿体采用大面积下向胶结充填、沿走向连续回采而不留间隔矿柱回采提供了理论依据。本项成果已在金川二矿区应用并取得了明显的效益。     

反应－气相色谱法测定微量一氧化碳和二氧化碳气体的研究

提出了用反应－气相色谱法测定微量ＣＯ和ＣＯ２气体的方法．试验了载气流速、反应温度和催化剂的装置位置等与ＣＯ和ＣＯ２转化为ＣＨ４的关系．得出了最佳条件：载气流速４０～６０ｍＬ／ｍｉｎ；反应温度：ＣＯ６５０℃，ＣＯ２６００℃；分离温度６０℃．以北分厂和标准计量所的标气为参照，测定了佛山分析仪器厂自配的气体，获得了满意的结果．方法的相对偏差在±５％以下，此法也适用于金属中微量碳的测定．