微乳液技术在纳米粒子制备中的应用

由于对控制微粒尺寸具有独特的优势 ,微乳液方法制备纳米材料正在引起人们的极大兴趣。介绍了微乳液方法及其微反应器的形成和结构 ,讨论了影响微乳液法制备纳米粒子形态和大小等方面的因素及应用研究进展。     

以反相微乳液介质调控微/纳米SiO2的尺寸和形貌

简单介绍了微/纳米SiO2的优点和应用;阐述了反相微乳液中制备SiO2的反应原理和具体过程;结合近年来国内外文献综述了改变微乳液的参数对SiO2粒子的尺寸及形貌等的调控措施,并对反相微乳液法制备纳米材料的发展前景进行了展望。     

反胶束微乳法制备无机功能纳米材料

介绍了微乳法制备无机纳米粒子的一般实验室方法 ,讨论了影响粒径及其分布的有关因素。比较了微乳液法与传统的制备方法的优劣 ,探讨了无机功能纳米材料研究进展并提出了今后研究工作的展望。     

W／O微乳液制备纳米粒子的研究

介绍了微乳液的制备方法、微观结构模型和形成理论;介绍了W／O型微乳液在制备纳米粒子方面的应用,并对微乳液法制备纳米粒子的方法、原理、影响因素以及纳米粒子的表征方法进行了重点介绍。     

产品开发

正发展磁性纳米材料前景广阔磁性纳米材料根据磁化率的大小分为抗磁性与顺磁性、铁磁性与反铁磁性等不同的磁性材料。比较成熟的磁性纳米材料制备技术是氧化铁纳米粒子的合成制备,主要有水溶液共沉淀、微乳液、水热和热分解等化学合成法,蒸发冷凝和机械球磨等物理合成法,以及生物合成法。磁性纳米材料已     

表面活性剂在纳米材料制备领域的研究概况

表面活性剂是用途非常广泛的一类两亲分子,现如今已运用在纳米粒子模板,有机化学制备等诸多领域。而纳米材料的微乳液合成方法是一项日趋完善的技术,它可以用于控制许多有机和无机材料的粒子尺寸。本文将对表面活性剂,以及表面活性剂在溶液中形成的微乳液制备纳米材料的应用趋势做详细的介绍。     

微乳液法制备纳米颗粒及其在陶瓷材料中的应用

与传统的纳米材料制备方法相比, 微乳液法具有明显的优势.全面地讨论了微乳液中纳米微粒的形成机理和影响因素, 微乳液法的特点及其在陶瓷材料制备中的应用.     

W/O微乳液技术与纳米粒子的控制合成

分析了W／O微乳液的形成机理、结构特征以及用W／O微乳液法合成纳米粒子的基本原理。讨论了制备条件如水与表面活性剂的比值,反应物、表面活性剂、助表面活性剂的浓度以及焙烧条件对纳米粒子特征的影响。指出应该加强对纳米粒子生成反应动力学的研究,加强微乳液法与其它纳米粒子制备技术的耦合研究,并注意改善非极性溶剂和表面活性剂的回收率以降低制备成本。     

微乳液法制备纳米粒子的研究进展

微乳液是一种具有热力学稳定性的单分散体系，其分散质点为纳米量级，它能够为纳米粒子的制备提供理想微环境：介绍了微乳液的性质以及利用微乳液制备纳米粒子的原理和方法，并讨论了利用微乳液制备纳米粒子过程中的各种影响因素。     

微乳化技术在纳米材料制备中的应用研究

微乳化技术在许多技术领域都具有潜在的应用前景。本文从纳米粒子制备的角度出发,论述了微乳反应器的原理、形成与结构,并对微乳液在纳米材料制备领域中的应用状况进行了阐述。     

Characterizing Shape of Effluent Particles by Image Analysis

Abstract

Particle shape of wastewater effluents were investigated by implementing a dynamic particle image analyzer which provided data on the particle count, size, shape and circularity concurrently with images. The goals of this study were to characterize removal efficiency based on size and shape parameters for an in‐line filtration process and to study correlation between size and shape parameters. Results showed that filter removal efficiency can be determined by various size and shape parameters, where different information is obtained for each analysis. This method has potential in evaluating treatment process efficiencies by coupling size and shape parameters into a meaningful tool.     

Size and Shape of Calcium Alginate Beads Produced by Extrusion Dripping

Alginate hydrogel beads are widely used as an encapsulation medium for biomedical, bioprocessing, and pharmaceutical applications. The size and shape of the beads are often critically controlled since in many usages the beads are monodisperse in size and spherical in shape. Extrusion dripping is a well‐known method to produce alginate beads. Nevertheless, the production of beads of desired size and spherical shape is often achieved based on one's experience or trial and error. An overview is provided on alginate properties, formulation and preparation of alginate and gelling solutions, production conditions, and post‐production treatment that may influence the bead size and shape. Various methods of bead size and shape measurement are also discussed.     

Morphological fourier descriptors

The Fourier method of particle profile representation is presented and discussed. Rotationally invariant size and shape terms are derived from the Fourier particle profile representation. The shape terms are demonstrated to be rotationally invariant as well as magnification (size) invariant.The size and shape terms proposed are shown to include all the available information about the boundary of a particle profile. Mathematical and statistical interpretations of the size and shape terms proposed are demonstrated. Some actual and potential applications are discussed.     

Partikelform und Porosität von biogenen Pyrolysekoksen

Char particles from pyrolyzed biomass vary in particle size and shape. On average, the particles are more elongated the larger their size. The average size‐specific elongation is almost alike for all investigated samples, i.e. independent from their source material and process. The particle collectives cannot be characterized accurately with classical particle size distributions, which assume spherical particle shape. Accounting for their shape, they can be described more accurately with particle size distributions that are based on an ellipsoid model. The high bulk porosity is mainly attributed to the spaces between particles.     

Granular size and shape effect on electrostatics in pneumatic conveying systems

In solid processing systems, electrostatic problems are commonly observed for granules composed of various sizes and shapes. However, complete understanding about the functional dependence of electrostatic charge generation and transfer on the particle shape and size distributions has yet to be established. This observation has motivated the present study where novel methods are proposed to examine the effect of particle size and shape distributions on electrostatics. In this work, polyvinyl chloride (PVC) granule (original diameter 3.35-4.1 mm, in the shape of cylinders) was first discharged to remove any residual charges and subsequently its electrostatic charging was studied. Granular size and shape were varied by mechanical attrition conducted in a rotary valve jointly with a pneumatic conveying system. Characterised by induced current, particle charge density and equivalent current of the charged granular flow, granular electrostatics was found to increase with the extent of granular attrition in a continuous recycled pneumatic conveying process. In a separate setup, single particles (collected from the attrited granules formed in the rotary valve) were examined by correlating the extent of charge variation with size/shape. It was found that a dimensionless group, defined by the ratio of charge variation to size variation, is useful in describing the particle attrition process as this parameter increased with decreasing granule size. Smaller granules were found to be the main contributors in the enhancement of electrostatics charge density in bulk particles. By a separate shape analysis, it was uncovered that face shape requiring more shearing actions for its formation tended to give rise to a higher charge variation and so did column geometry. In this fashion, charge variation evaluated for whole attrited granules exhibited good agreement with the temporal variation of attrition weight; this applied for all air flow rates used in the conveying system. Furthermore, there is a reasonably good matching between results obtained by shape and size analyses.By the correlations presented above for single particle electrostatics either by size or shape analysis, charge variation of granular flow matched very well with that measured in the conveying system as well as the attrition process in the rotary valve. As such, the joint granule size and shape analysis has proven to be useful for characterisation of electrostatics in conveying systems where granules are made up of complex combinations of different particle sizes and shapes.     

Transport properties of eastman cellulose acetate membranes: Influence of diffusant size and shape on permeability

Eastman cellulose acetate membranes (acetyl content = 40%) have been studied by means of dialysis rate experiments with uncharged permeants of selected sizes and shapes. The experimental results show that the high flux membranes exert no molecular size or shape selectivity on the transport of permeants whose molecular weights are less than 1152. The membranes used in desalination, however, are selective as to molecular size and shape. Desalination membranes, therefore, may be useful in separations where differences in size and shape are present.     

硅砂对高碱铝硅酸盐玻璃熔解特性的影响研究(英文)

通过固定熔制工艺制度,研究了硅砂原料粒径大小、分布情况、颗粒形态对高碱铝硅酸盐玻璃熔解特性的影响关系。研究结果表明:在玻璃配合料熔制过程中,白色未熔物的产生与石英砂密切相关,石英砂粒径处于45-150μm范围熔化效果最好,石英砂粒度分布为正态分布的熔化效果优于均匀分布,经过粒化处理的石英砂比破碎处理的熔化特性更优,可促进玻璃的熔化。     

Shape and size of microfine aggregates: X-ray microcomputed tomography vs. laser diffraction

Microfine rock aggregates, formed naturally or in a crushing process, pass a #200 ASTM sieve, so have at least two orthogonal principal dimensions less than 75 μm, the sieve opening size. In this paper, for the first time, we capture true 3-D shape and size data of several different types of microfine aggregates, using X-ray microcomputed tomography (μCT) with a voxel size of 2 μm. This information is used to generate shape analyses of various kinds. Particle size distributions are also generated from the μCT data and quantitatively compared to the results of laser diffraction, which is the leading method for measuring particle size distributions of sub-millimeter size particles. By taking into account the actual particle shape, the differences between μCT and laser diffraction can be qualitatively explained.     

水包水多彩涂料彩粒大小与形状的影响因素研究

研究了多彩涂料保护膜形成机理,以及彩粒形状和大小的影响因素。讨论了保护胶体用量和保护胶体中磷酸用量对彩粒大小及形状,以及羟乙基甲基纤维素用量对分散相的黏度以及彩粒大小的影响。     

封接玻璃喷雾造粒粉粒径分布、颗粒形貌对粉体流动性的影响

研究分析了封接玻璃喷雾造粒粉粒径分布、颗粒形貌对造粒粉流动性的影响。研究表明,封接玻璃喷雾造粒粉颗粒的形状、大小、表面状态和堆积密度是影响造粒粉流动性的主要因素,其中,封接玻璃喷雾造粒粉粒径分布峰值范围的质量分数对造粒粉流动性起决定作用。对此结果,从封接玻璃喷雾造粒粉粒径分布、颗粒微观形貌进行了分析。