物理场强化溶液结晶应用研究进展

结晶是食品和化工分离中的一个重要单元操作。文章阐述了溶液结晶的原理，综述了超声场、微波场、静电场、磁场等物理场在溶液结晶中的应用，分析和探讨了它们对溶液结晶的影响机理，并且对今后的发展进行了展望。     

溶液结晶研究进展

本文综述了近期溶液结晶的研究进展及其在工业生产中的应用实例。     

物理场强化化工过程的研究进展

物理场已成为化工传递过程强化研究的热点之一.综述了超声、磁场、静电场、微波等物理场在强化化工过程中的研究进展情况,指出设备开发和制定规模放大准则是当前面临的主要挑战,应加强物理场强化化工过程的机理研究.     

物理场强化气液传质的研究进展

分别简述了磁场、电场、电磁场、超声场和超重力场5种物理场的作用机理,综述了这些物理场在强化蒸发、精馏和气体吸收等气液传质过程中的研究进展,同时概述了物理场强化气液传质的热力学研究进展。分析表明,物理场强化气液传质在化工、环保和节能减排等领域具有广泛的应用前景,但目前的研究大多还处于实验阶段,其机理和各种因素对强化效果影响的研究还不够深入和完善。指出今后研究热点主要包括：继续探索物理场强化传质的作用机理,拓展其应用领域,并对过程中的瓶颈问题进行技术攻关;通过实验和热力学研究两种方法对不同种类物理场强化传质效果进行比较,以确定各种物理场的适用体系。     

磁场影响溶液结晶过程研究进展

论述了磁场对溶液结晶过程影响的研究进展情况，指出磁场不仅可以化溶液结晶过程，刺激结晶成核，提高结晶生长速率，控制晶体粒径的分布，也可抑制溶液的结晶，降低结晶生长速率。针对不同的工程目的，选择合理的磁处理参数显得尤为重要。并提出磁场技术目前存在的问题和展望。     

溶液结晶法制五水偏硅酸钠

简要叙述了溶液结晶法制五水偏硅钠原理，重点讨论了结晶溶液浓度、降温速度、晶种对产品质量的影响。     

物理场强化萃取新技术及应用

萃取技术是一个重要的分离技术，在化工、环保等很多领域具有广泛的用途。应用微波、超声场、电场、磁场强化萃取过程，可有效地提高萃取得率，缩短萃取时间，提高生产效率，而且是与“环境友好”的新技术，深受人们的青睐。本文对这四种物理场强化萃取的原理和应用研究分别予以论述，并指出了这些方法目前所存在的问题及今后研究的方向。     

探索溶液结晶的奥秘

溶液结晶是固体物质从溶液中结晶析出的过程,现在为数众多的化工产品都是以结晶形态出现,搞清溶液结晶理论对发展化工生产意义重大。     

物理场强化植物多糖提取研究进展

介绍了超声、微波及高压脉冲电场等物理场技术在多糖提取方面的应用,分别阐述了它们提取多糖的原理与特点,并对影响因素进行了分析,同时还探讨了物理场与其他技术协同对多糖提取的影响,最后对物理场技术提取多糖的前景进行了分析与展望.     

固体溶液的结晶提纯

简单介绍了连续结晶与间歇结晶方法。重点说明了有机物的间歇结晶分离问题，根据作者实践经验，要使间歇结晶获得合格的产品和较高的收率，必须掌握好以下几个问题：相图的使用、“发汗”问题、结晶速度和传热系数。     

Flow-induced crystallization from solution: The relative effects of extension and shearing flow fields

Calculations have been performed to evaluate the relative effects of extensional and shearing flow fields on both the chain elongation and crystal nucleation rate enhancement for polyethylene crystallizing from xylene solutions. Rheological behavior was evaluated by means of the elastic dumbbell model modified for nonlinear effects at high elongations, and nucleation rate effects were considered from an essentially phenomenological view point. Molecular weight effects were also incorporated explicitly in the computations. Results show that chain elongation and nucleation rate enhancement is far greater for extensional than for shearing flows. Semiquantitative comparisons with experimental results reported in the literature for various aspects of the flow induced process, including the important fractionation effects, are discussed. Modification of the dumbbell model to account for shear rate effects on the intrinsic viscosity is also discussed.     

超细晶体的研究进展

超细晶体由于其尺寸小、比表面积大等独特性质而被广泛应用于医药、化工等领域。综述了超细晶体的制备方法,以及各种制备方法的原理和粒度控制参数。总结了超细晶体在吸入剂、含能材料以及难溶药物等领域的应用,同时对超细晶体悬浮液的稳定性、颗粒聚结进行了讨论分析,并对超细晶体的发展提出展望。     

Industrial crystallization from solution

This review approaches crystallizer performance from a reaction engineering viewpoint in which emphasis is placed on the interaction of crystallizer fluid mechanics and residence time distributions with the physical chemistry of nucleaton and growth kinetics to produce the crystal size distribution within a crystallizer. The present state of knowledge in these various areas is assessed, particular attention being paid to work carried out over the past decade. Great advances have been made during this period but significant gaps in our understanding still exist, particularly in the areas of crystallizer fluid mechanics (especially the role of micromixing), primary nucleation, habit modification, comparison of predicted crystallizer performance with actual operating characteristics, and the control of full scale crystallizers.     

超细晶体的研究进展

超细晶体由于其尺寸小、比表面积大等独特性质而被广泛应用于医药、化工等领域。综述了超细晶体的制备方法,以及各种制备方法的原理和粒度控制参数。总结了超细晶体在吸入剂、含能材料以及难溶药物等领域的应用,同时对超细晶体悬浮液的稳定性、颗粒聚结进行了讨论分析,并对超细晶体的发展提出展望。     

聚丙烯在溶液中的等温结晶行为

采用差示扫描量热仪（DSC）分析聚丙烯（PP）在2种不同溶剂中的等温结晶过程,并使用Avrami方程研究等温结晶动力学。 结果表明,晶体生长速率随着结晶温度的升高而降低。 同时,根据Lauritzen⁃Hoffman 二次成核理论,PP在溶液中的成核常数K_g和折叠表面自由能σ_e低于PP原料,反映了其在溶液中的结晶速率较高。     

Use of exfoliated graphite filler to enhance polymer physical properties

Three sets of exfoliated graphite filled polymers, having three different particle sizes, were prepared with load levels from 0.1-20% by weight. After sieving, the particles were reduced to nanometer size through exfoliation, shear mixing, and ultrasonication, which further breaks and delaminates them. The electrical, thermal and mechanical properties of the nanoparticle filled polymers were measured. In addition, light, scanning electron, and atomic force microscope characterization were performed. The exfoliated graphite filled polymer material could be tailored to be high modulus and vary from insulating to highly conducting. Compared with the pure polymer, the polymers filled with 20% wt. exfoliated graphite has seen an significant reduction in electrical resistivity from 1.5⁸ to 0.5 Ω cm. The thermal conductivity for the polymers containing 20% wt exfoliated graphite has also been drastically improved, increasing from 0.2 to 5 W/m K. The flexural modulus achieved a maximum increase of 3.8 GPa which is a 60% above the value for the pure polymer (2.4 GPa).     

Kinetics of the xylitol crystallization in hydro-alcoholic solution

Nývlt method was used to determine the kinetic parameters of commercial xylitol in ethanol:water (50:50 %w/w) solution by batch cooling crystallization. The kinetic exponents (n, g and m) and the system kinetic constant (B_N) were determined. Model experiments were carried out in order to verify the combined effects of saturation temperatures (40, 50 and 60 °C) and cooling rates (0.10, 0.25 and 0.50 °C/min) on these parameters. The fitting between experimental and calculated crystal sizes has 11.30% mean deviation.     

硫铵溶液蒸发结晶技术的探讨

介绍了硫铵溶液常用的蒸发结晶技术，常压单效蒸发、减压单效蒸发、喷射式热泵单效蒸发及多效蒸发的工艺流程、消耗定额，及其蒸发设备材质的选择。