膜污染程度的评价指标——膜孔堵塞率

首先利用伯努力方程导出微孔过流断面的流速,其次引用水力学中元流的概念,推导出超滤膜的有效过滤面积,然后通过一定的方法推导得出膜孔堵塞率概念.该膜污染程度评价指标不受膜运行方式的限制,特别是恒定通量运行方式的限制,用其评价膜的污染程度,具有一定的优势.     

变压膜渗透空气分离制氧实验研究

在稳态膜渗透的基础上提出了一种新的非稳态渗透流程。该流程是一种循环操作过程,每一周期包含加压、抽真空以及排空三个阶段。实验研究了加压时间、抽真空时间和排空时间对空气分离制氧的产品平均纯度、平均流量和回收率的影响,并与稳态渗透实验结果进行了比较。结果表明,当富氧纯度相同时,变压渗透过程能够得到比稳态渗透更高的氧气回收率和富氧流量。     

乳状液制备新工艺——膜乳化过程实验研究

用膜乳化系统制备了Ｏ／Ｗ型乳状液,考察了乳化时间、平均膜孔径、壁面剪应力、膜两侧压差和乳化剂等因素对乳化效果的影响．实验显示,分散相液滴平均直径不随乳化时间而变化;在此条件下,该直径约是膜平均孔径的５～１２倍．随着连续相一侧壁面剪应力的增大液滴平均直径减小,但当壁面剪应力大到一定值后,减小的幅度变得很小．增大膜平均孔径和膜两侧压差都将增加分散相透过膜的通量．此外,乳化剂分子的吸附速度越快,分散相液滴平均直径越小．     

液滴蒸发过程理论分析及非稳态过程数值求解

建立了球对称的液滴在空气中蒸发时分子扩散的微分方程，通过求解得到了液滴质扩散速率的数学表达式。建立了液滴蒸发非稳态阶段的数学模型，并用迭代方法对该模型进行了数值求解。求解的结果表明：非稳态阶段的过程很短，液滴尺寸的变化很小。     

木瓜蛋白酶动态膜结晶的实验研究

采用聚偏氟乙烯中空纤维微孔膜,考察结晶过程中蛋白质溶液和洗脱液流速的改变以及不同膜面积对溶剂跨膜通量及木瓜蛋白酶晶体尺寸的影响.结果表明:在以pH值为4.7的0.1 mol/L醋酸钠为缓冲溶液、1%的(NH4)3PO4为沉淀剂以及25%的MgCl2溶液作为洗脱液的木瓜蛋白酶动态膜结晶中,当有效膜面积为62.83 cm2,蛋白质溶液和洗脱液流速分别控制在4 744μm/s和1.37×104μm/s的高流速时膜组件的效率得到最大发挥,并得到了较大尺寸的木瓜蛋白酶晶体;当膜面积不同时,溶剂跨膜通量的衰减随着膜面积减小而趋于平缓.     

高岭土动态膜的制备

以陶瓷膜管为基质,研究了高岭土动态膜的制备过程.实验以高岭土为动态膜预涂材料,采用错流操作对膜管进行涂膜,通过记录和分析涂膜过程中的渗透液通量和测定在此过程中涂上的高岭土的量随时间的变化,研究了高岭土粒径、涂膜液浓度、跨膜压力、错流速度和涂膜时间对涂膜效果及清水通量的影响,对涂膜过程有了较好的认识,并得出最佳涂膜条件为:涂膜液质量浓度0.3 g/L、跨膜压力0.2 MPa、错流速度0.5 m/s及涂膜时间10 min.     

介孔分子筛膜的制备及应用

介孔分子筛膜是最近十几年新兴的研究领域,它的出现丰富了有序介孔材料的研究范畴,拓宽了介孔材料的应用范围.作为一种新型的无机膜,介孔分子筛膜不仅具有微孔无机膜的优点,还在大分子催化分离领域具有潜在的应用价值.本文主要介绍了国内外近年来在无机介孔分子筛膜制备和应用方面的最新研究进展,并指出介孔分子筛膜目前存在的主要问题是热稳定性和水热稳定性差,导致其实际应用受到很大的限制.介孔分子筛膜今后主要的发展方向是加强其热稳定性和水热稳定性的研究,此外,制备取向生长的介孔分子筛膜,实现结构优化,将会成为今后介孔膜发展的新的热点.     

聚丙烯亲水性微孔膜的制备及在锂电池中的应用

以聚丙烯接枝马来酸酐(PP-g-MAH)为改性剂与聚丙烯熔融共混,通过单向拉伸工艺制备亲水性聚丙烯微孔膜。使用差示扫描量热仪和红外光谱表征流延基膜的取向片晶结构,使用压汞仪和扫描电镜表征微孔膜的孔结构,使用Gurley值、水接触角和水蒸气透过率表征微孔膜的透过性和亲水性,将微孔膜组装成电池并测定电池的性能,研究PPg-MAH含量对微孔膜孔结构、亲水性、透过率及电池性能的影响。结果表明,PP-g-MAH共混含量为2.5%的微孔膜孔隙率和透气性得到提升,进一步增加PP-g-MAH含量会导致微孔膜孔结构变差,透过性能下降。微孔膜表面亲水性随PP-g-MAH含量增加持续改善,水蒸气透过率在PP-g-MAH含量为5%时达到最大值,但由于微孔膜孔结构在较高PPg-MAH含量下受到破坏,使得高PP-g-MAH含量下微孔膜水蒸气透过率下降。PP-g-MAH含量为2.5%和5%的微孔膜由于具有较好的孔结构和一定的电解液浸润性,使得锂电池的电荷转移电阻较低,首次充放电比容量较高。     

炭膜制备及其孔结构调控

炭膜作为近年发展起来的一种新型无机分离膜,有着广阔的应用前景.炭膜的孔结构是影响炭膜性能的根本性因素.评述了炭膜的分类和制备,着重阐述了原料性质、添加剂、炭化条件等主要因素对炭膜支撑体孔结构的影响以及预氧化条件对沥青基非支撑体炭膜孔结构的影响.并详细介绍了炭膜分离层孔结构的调控方法.     

溶菌酶动态膜结晶传质过程研究

采用聚偏氟乙烯中空纤维微孔膜对溶菌酶动态膜结晶进行了实验研究,重点考察动态结晶过程中的结晶溶液流速和洗脱液流速对溶剂跨膜通量及总传质系数的影响.结果表明,跨膜通量和总传质系数均随实验的进行而减小;总传质系数不仅与操作条件有关,还与结晶溶液中蛋白质的浓度有联系.     

Computer technologies in stability measurements on stationary states in dynamic biological systems

A mathematical treatment is given for the concept of steady state in a dynamic biological system. Advantages are discussed of identifying biosystems in this way and results are given for measurements on steady states in dynamic biological systems by reference to the brain neuron network in mammals. __________ Translated from Izmeritel'naya Tekhnika, No. 1, pp. 40–45, January, 2006.     

基于结构动力学方法的气动弹性分析

摘 要：对于气动与弹性的耦合模型,给出气动力的频域公式,并表示成有理多项式,通过等价的变换,能够推导出与结构动力学方程完全相似的、关于求解变量的二阶常微分方程组。于是,可以在计算结构动力学框架下实现气动弹性问题的分析和计算。此方法将通用计算结构动力学程序的功能与试验或数值分析得到的气动力模型相结合,简化了气动弹性的耦合分析、提高计算效率。     

Synthetic and Runs‐Rules Charts Combined With an Chart: Theoretical Discussion

A synthetic and a runs‐rules charts that are combined with a basic chart are called a Synthetic‐ and an improved runs‐rules charts, respectively. This paper gives the zero‐state and steady‐state theoretical results of the Synthetic‐ and improved runs‐rules monitoring schemes. The Synthetic‐ and improved runs‐rules schemes can each be classified into four different categories, that is, (i) non‐side‐sensitive, (ii) standard side‐sensitive, (iii) revised side‐sensitive, and (iv) modified side‐sensitive. In this paper, we first give the operation and, secondly, the general form of the transition probability matrices for each of the categories. Thirdly, in steady‐state, we show that for each of the categories, the three methods that are widely used in the literature to compute the initial probability vectors result in different probability expressions (or values). Fourthly, we derive the closed‐form expressions of the average run‐length (ARL) vectors for each of the categories, so that, by multiplying each of these ARL vectors with the zero‐state and steady‐state initial probability vectors, yield the zero‐state and steady‐state ARL expressions. Finally, we formulate the closed‐form expressions of the extra quadratic loss function for each of the categories. Copyright © 2016 John Wiley & Sons, Ltd.     

变速直膨式空调系统运行特性的稳态ANN模型

在假设系统输出显、潜冷量的相对值在不同的蒸发器入口空气状态下不发生明显变化的前提下,本文针对实验用变速直膨式空调系统建立了稳态人工神经网络(ANN)模型,预测其在不同压缩机、风机转速组合下的系统输出,利用输出显、潜冷量的相对值可以消除室内空气状态对系统输出的影响。通过稳态实验获得数据训练、检测并验证ANN模型预测变速直膨式系统运行特性的准确性,并通过非训练状态点下的稳态实验验证所提出假设与ANN模型的适用性。ANN模型的训练、检测以及验证实验结果的最大误差均小于5%,平均误差均小于3%,表明该稳态ANN模型可以在训练状态点以及非训练状态点较为准确地预测变速直膨式系统的运行特性。     

Theoretical analysis of the membrane parameters of the fiber optic microphone

In the membrane displacement equation of fiber optic microphone, there are, beside the pressure, two kinds of parameters: membrane parameters and damping mechanism parameters. The first kind, which consists of the membrane radius, surface density and border tension, has an effect on the sensitivity and the acoustic frequency band (sonic and ultrasonic), whereas the second kind has almost no effect. The theoretical analysis of these parameters shows that some ultrasonic frequencies can cover a band close to 100 kHz, for a radius of 0.1 mm, with the increase of the sensitivity. This analysis provides a general approach useful to design a fiber optic microphone for a particular application.     

修理工N-策略休假的带有温贮备的可修系统的可靠性分析

修理工休假的多部件温贮备可修系统模型广泛应用于电力系统,医疗设备系统和制造系统等领域.本文研究了修理工N-策略休假的多部件温贮备可修系统,探讨该系统的稳态可用度和稳态故障频度.利用Markov过程理论和递归迭代的方法,求出了系统稳态概率的迭代计算公式,并进一步得到了系统稳态可用度和稳态故障频度.     

Unsteady‐ and steady‐state gas permeation through active packaging walls

Steady‐ and unsteady‐state gas permeation rates through packaging walls containing active (scavenger) materials are determined as functions of the system's physical parameters and the scavenger load. With the simplifying assumptions of constant scavenger concentration and first‐order reaction kinetics, steady‐state analysis shows that there is a minimum quantity of scavenger that must be added to the packaging wall if any reduction of gas permeation is to be achieved. Unsteady‐state studies have established the dependence of the time needed to reach stationary behaviour on the system's physical parameters. Copyright © 2007 John Wiley & Sons, Ltd.     

充气膜结构零应力态求解

充气薄膜管属于柔性结构,荷载作用下产生的变形,会引起其内压改变,进而导致外围薄膜刚度的变化,对其变形产生重要影响,表现出内充气体压力与外围薄膜变形相互耦合的特点。该文采用有限元方法分析气-膜耦合作用对充气薄膜管动力特性的影响及其随影响因素的变化规律。通过将内充气体看作小扰动线性势流以考虑气-膜耦合作用以及内充气体附加质量的影响;通过建立内充气体的三种等效模型,分别将内充气体作用等效为外围薄膜静力边界条件、考虑内充气体附加质量影响的静力边界条件以及小扰动线性势流体,并将其相应的有限元分析结果进行对比,研究气-膜耦合作用和内充气体附加质量对充气薄膜管自振特性的影响及其随初始内压、长细比、膜厚以及端部约束类型的变化规律。研究结果表明：气-膜耦合作用以及内充气体的附加质量对低阶自振模态没有明显影响;气-膜耦合作用对自振频率有较显著的影响作用,而内充气体附加质量的影响则较小;随初始内压和长细比的增加,气-膜耦合作用对频率的影响体现出因阶次不同而不同的变化规律;气-膜耦合作用对频率的影响随膜厚的增加而降低,随约束程度的减弱而增强。该文的研究成果揭示了气-膜耦合作用对充气薄膜管自振特性的影响规律,有助于深入认识充气薄膜管的动力行为,确保其设计计算的合理性和可靠性。     

Quantitative analysis of pores of two types in a plasma-sprayed coating

Quantitative microstructural analyses of thermally sprayed coatings are reviewed. Then a ceramic plasma-sprayed coating is analysed using light microscopy and image analysis. Globular pores and interlamellar flat pores are reconstructed from serial sections of a specimen and their volume and surface area histograms are estimated. The spatial distribution of pores is described using a method based on 3D distances and testing of complete spatial randomness is performed. Interpretations of results in terms of the physical background of the material are discussed.     

Post-buckling analysis of shell and membrane structures by dynamic relaxation method

The family of arc-length method has been used for the post-buckling analysis of structures. However, it often becomes intractable for complex nonlinear problems. For instance, the incremental solution hangs about and never reaches the desired deformation when wrinkling appears after the buckling of membrane structures. In order to cope with this problem, alternative methods have been proposed, e.g., the dynamic relaxation (DR) method and the DR arc-length method. The applicability of these methods to the post-buckling analysis of shell and membrane structure is investigated in the present research, where the mixed interpolation of tensorial components (MITC) shell element is used for the FE modeling. It is shown that the DR and the DR arc-length methods are much more robust than the arc-length method, but for complicated nonlinear problems, a continuous deformation path can not be obtained by any of the three methods.