浅析内置百叶中空玻璃制品遮阳系数

介绍了内置百叶中空玻璃制品的遮阳系数,分析其在夏热冬冷地区使用的节能意义,通过比较实测法与计算法在测试结果上的差异,分析原因并得出实测法更加科学准确的结论。     

用气液色谱法测定氯辛烷

用气液色谱法测定氯辛烷,具有比经典法快速,简单、样品用量少,易推广等优点。本文测定氯辛烷与醇类在PEG中不同温度下的比保留体积,分配系数,活度系数和亨利系数,研究了固定相流失量等,提高了测试精度。     

用气液色谱法测定氯辛烷

用气液色谱法测定氯辛烷,具有比经典法快速,简单、样品用量少,易推广等优点。本文测定氯辛烷与醇类在PEG中不同温度下的比保留体积,分配系数,活度系数和亨利系数,研究了固定相流失量等,提高了测试精度。     

第二液相强化气体吸收传质

在油水体系下,讨论了油分率、搅拌转速、分配系数等相关参数对气液传质过程强化的影响,通过在非稳态的条件下,计算出总体积传质系数(k_Lα)和分配系数(m_(sw)).结果表明,分配系数对增强因子有着显著的影响;总体积传质系数随着分散第二液相的加入而显著的增加,当油分率为3%时,体积传质系数最大;分散相对传质系数的影响,主要取决于搅拌转速,当转速为650～700 r/min时,体积传质系数最大.     

双管程管式换热器的换热性能研究

以双管程管式换热器为研究对象,利用数学模型,分别计算换热器管内hi和管外he的换热系数,为该型形的换热器推广应用提供数据参考与理论基础。     

阻尼材料动态阻尼系数的测定

相同的阻尼材料,采用不同尺寸的测试试件测定的阻尼系数存在很大的差异。本文提出了频率对阻尼系数的影响,探讨了动态阻尼系数的测试方法,将相同阻尼材料、不同试件测定的结果统一起来。     

国标GB/T2624-93要点

介绍了新旧标准的不同之处,新标准中与使用有关的主要规定以及迭代计算方法。     

碳纳米管材料导热性能的实验研究

本文对碳纳米管与环氧树脂(Epoxy-EP)复合材料的导热性能进行了定量的研究,探索了CNTs/EP复合材料的制备方法,运用Hotdisk热常数分析仪研究了CNTs/EP复合材料的导热系数;利用CNTs/EP两相复合材料的导热理论模型得到了室温下单壁碳纳米管(Single-Wall Carbon Nanotubes-SWCNTs)的导热系数为3980 W/(m.K),双壁碳纳米管的导热系数(Double-Wall Carbon Nanotubes-DWCNTs)为3580 W/(m.K),以及多壁碳纳米管(Multi-Wall Carbon Nanotubes-MWCNTs)的导热系数为2860 W/(m.K)。     

利用惯性系数β研究储层应力敏感及非均质性

利用CMS-300岩心自动分析仪,通过对惯性系数β与有效应力的关系分析,发现对低渗透储层,二者之间的变化规律符合幂函数关系,并进行了理论分析,通过非均质系数（Hi）与储层渗透率的关系研究,发现渗透率越高,其非均质系数越小。研究认为,可以利用惯性系数β研究储层应力敏感,利用非均质系数进行储层非均质性的评价,尤其是对低渗储层,更有说服力。     

橡胶热传导性能的测定

介绍橡胶热传导性能测定的基本原理及导热系数,热扩散系数和比热容的测量方法。     

Cellulose nanofibres and cellulose nanowhiskers based natural rubber composites: Diffusion,sorption, and permeation of aromatic organic solvents

This article investigates the transport behavior of three aromatic organic solvents, viz. benzene, toluene, and p‐xylene in natural rubber nanocomposite membranes containing cellulose nanofibres (CNFs) and cellulose nanowhiskers (CNWs) isolated from bamboo pulp. The solvent molecules act as molecular probes to study the diffusion, sorption, and permeation through the nanocomposites, and provide information on the nanocomposite structure and matrix–filler interactions. Both the nanocelluloses were found to decrease the uptake of aromatic solvents in nanocomposite membranes, but the effect was more significant in the case on nanofibers compared to nanowhiskers. Furthermore, the uptake decreased with increased penetrant size; being the highest for benzene and the lowest for p‐xylene. Transport parameters such as diffusion coefficient, sorption coefficient, and permeation coefficient have been calculated. Comparison of the experimental values of equilibrium solvent uptake with the predicted values indicated that both the nanocelluloses have restricted the molecular mobility at the interphase and thereby decreased the transport of solvents through the materials; being more significant for nanofibers. The results showed that both the used cellulosic nanomaterials act as functional additives capable of manipulating and tailoring the transport of organic solvents through elastomeric membranes, even at concentrations as low as 2.5 wt %. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

新型干法水泥工厂的电力负荷计算方法

需要系数是采用需要系数法进行工业装置供电负荷计算的重要参数,其取值的合理与否,对用电设备和电气设备本身均有影响。简要介绍了五种常用的负荷计算方法,重点介绍了需要系数及需要系数法的相关计算。其中对影响需要系数取值的部分因素进行了对比分析,指出了目前常用计算方法存在问题及不足;并以工程实例的计算分析为例,提出了通过实测确定需要系数的具体方法,以使需要系数的取值尽可能合理,计算负荷更接近装置实际运行情况。     

Low-E玻璃的热工性能评价指标

通过分析Low-E膜的节能原理与Low-E中空玻璃的传热原理,详细介绍了影响传热系数的各种因素并对各类Low-E玻璃的性能进行对比。     

Effects of uniaxial tensile strain on the release of small molecules from silicone rubber

Silicone rubber materials may be subject to mechanical strains which can affect the transport properties of small molecules loaded in the materials such as plasticizers and active molecules, hence deteriorating their intended mechanical properties or affecting their performance as carriers of active molecules. Therefore, it is important to understand the effects of mechanical strains on transport of small molecules in the silicone rubber matrix. In this work, silicone rubber sheets loaded with 2 wt% triacetin were stretched and held at four different lengths up to 125% engineering strain. The mass transfer coefficients and diffusion coefficients of triacetin in the strained silicone rubber were determined by monitoring the release of triacetin using headspace gas chromatography–mass spectrometry. It was found that there was no significant change of diffusion coefficient as the applied strain increased, which might result from two microstructure changes that had conflicting effects on diffusion: chain orientation and free volume deformation.     

不同工况参数对酚醛树脂基无石棉闸瓦材料摩擦性能影响

针对WSM–3型酚醛树脂基无石棉摩阻材料,搭建实验装置研究WSM–3型闸瓦材料与16Mn钢摩擦副摩擦性能。根据实验数据,研究了瞬态/平均摩擦系数随不同接触压力、不同滑动速度及不同接触表面温度的变化规律,在考察多种曲线的基础上,分析瞬态/平均摩擦系数在不同工况参数下的变化特性,并探讨了闸瓦材料摩擦性能的变化机制。实验证实,闸瓦材料的摩擦性能不仅具有强烈的系统依赖性,而且与系统的工况因素具有强耦合性,在闸瓦材料摩擦学设计中将瞬态/平均摩擦系数视作变量是必要的。     

Adsorption and Diffusion of VO2+ and VO2 + across Cation Membrane for All‐Vanadium Redox Flow Battery

A method based on a selectivity coefficient and the Nernst‐Planck equation is proposed to determine diffusion coefficients of vanadium ions across a cation exchange membrane in VO²⁺/H⁺ and VO₂ ⁺/H⁺ systems. This simplified method can be applied to high concentrations of vanadium ions. Three cation exchange membranes were studied. The logarithmic value of the selectivity coefficient was linearly dependent on the molar fraction of vanadium ions in solution. The diffusion coefficient of vanadium ions decreased with decreasing water content. The membrane with the lowest diffusion coefficient was selected as a battery separator and showed the lowest capacity loss of the studied membranes.     

矿物掺和料对水泥浆体流变性能的影响

将几种活性和非活性矿物掺和料对水泥浆体流变性能的影响作对比试验,试验结果表明:矿物掺和 料的加入不改变水泥浆体的流变类型,但各种矿物掺和料的加入在一定程度上改变了水泥浆体的流变参数。     

粗糙颗粒碰撞参数对鼓泡流化床内气固流动模拟的影响

结合粗糙颗粒动力学理论和双流体方法,数值模拟了碰撞参数对鼓泡流化床内稠密气固两相流动特性的影响. 结果表明,增大摩擦系数或减小法向弹性恢复系数会使床内颗粒分布更为不均,并增强床层膨胀及压力降脉动. 合理选取摩擦系数模拟得到时均气固流场分布,与实验吻合,罂粟籽颗粒的摩擦系数取0.3~0.6较合适. 法向弹性恢复系数改变不影响时均气固流场分布的基本形态,其取值敏感性不如摩擦系数;切向弹性恢复系数对鼓泡流化床动态特性及时均气固流场的影响相对较弱.     

A Theoretical Model for the Nongray Radiation Drying of Polyvinylalcohol/Water Solutions

A theoretical analysis of heat transfer and moisture variation was performed while a PVA solution was exposed to high-intensity nongray irradiation and/or air flow convection. Effective absorption coefficients were incorporated in the radiative transfer analysis. The influence of various radiation and convection parameters on the transfer of heat and moisture variation in the coated layers on an optically thick substrate was investigated. The effects of radiation and convection parameters on the transfer process were presented in terms of the rate of water content removal, heat transfer, and moisture distribution. Results were compared to those of drying when using convective heat. It is evident that the use of thermal radiation combined with convective heat will help in improving the drying rate. Numerical results show that both the radiative energy absorbed by the solution and the substrate and the distribution of water mass fraction in the solution are closely related to the rate of water removal from the solution during the process.     

A Theoretical Model for the Nongray Radiation Drying of Polyvinylalcohol/Water Solutions

Abstract

A theoretical analysis of heat transfer and moisture variation was performed while a PVA solution was exposed to high-intensity nongray irradiation and/or air flow convection. Effective absorption coefficients were incorporated in the radiative transfer analysis. The influence of various radiation and convection parameters on the transfer of heat and moisture variation in the coated layers on an optically thick substrate was investigated. The effects of radiation and convection parameters on the transfer process were presented in terms of the rate of water content removal, heat transfer, and moisture distribution. Results were compared to those of drying when using convective heat. It is evident that the use of thermal radiation combined with convective heat will help in improving the drying rate. Numerical results show that both the radiative energy absorbed by the solution and the substrate and the distribution of water mass fraction in the solution are closely related to the rate of water removal from the solution during the process.