Theory of electrostatics and electrokinetics of soft particles

We investigate theoretically the electrostatics and electrokinetics of a soft particle, i.e. a hard particle covered with an ion-penetrable surface layer of polyelectrolytes. The electric properties of soft particles in an electrolyte solution, which differ from those of hard particles, are essentially determined by the Donnan potential in the surface layer. In particular, the Donnan potential plays an essential role in the electrostatics and electrokinetics of soft particles. Furthermore, the concept of zeta potential, which is important in the electrokinetics of hard particles, loses its physical meaning in the electrokinetics of soft particles. In this review, we discuss the potential distribution around a soft particle, the electrostatic interaction between two soft particles, and the motion of a soft particle in an electric field.     

Theory of electrostatics and electrokinetics of soft particles

Abstract

We investigate theoretically the electrostatics and electrokinetics of a soft particle, i.e. a hard particle covered with an ion-penetrable surface layer of polyelectrolytes. The electric properties of soft particles in an electrolyte solution, which differ from those of hard particles, are essentially determined by the Donnan potential in the surface layer. In particular, the Donnan potential plays an essential role in the electrostatics and electrokinetics of soft particles. Furthermore, the concept of zeta potential, which is important in the electrokinetics of hard particles, loses its physical meaning in the electrokinetics of soft particles. In this review, we discuss the potential distribution around a soft particle, the electrostatic interaction between two soft particles, and the motion of a soft particle in an electric field.     

软填料生物接触氧化法处理感光污水

软填料在射流曝气池内,采用悬挂安装工艺处理感光污水,在此特定条件下,软填料与新安装的蜂窝填料有同样效能,其优点大于蜂窝填料,克服了蜂窝填料堵塞的最大缺点。     

封套软包装的应用

介绍军品进行封套软包装的重要性,列举了封套软包装的特性和优点,包装材料的技术指标,以及大型产品的包装应用实例。     

Angular distribution of light scattered by single biological cells and oriented particle agglomerates

We used a flow cytometer together with an intensified CCD camera to record spatially resolved light scattering from micrometer-sized single particles and single oriented particle agglomerates. Experimental differential cross sections of an oriented dumbbell made from two identical polystyrene spheres were compared with theoretical values calculated within the discrete dipole approximation, and good agreement was achieved. Furthermore, characteristic two-dimensional patterns of the scattered-light intensity were recorded for single blood cells, yielding information on the cells' shape and volume. Besides flow cytometry, we observed and analyzed differential light scatter of particle clusters of known size, shape, and orientation located within an optical trap.     

软磁铁氧体材料和生产技术的新进展

本文着重介绍开关电源用高频低功耗铁氧体材料、彩色显示系统用铁氧体材料以及甚高磁导率铁氧体材料国内外最新进展和国外生产技术的新动向,并对国内生产技术以及生产设备的国产化作了展望。     

Review on development of electrolytes for dye-sensitized solar cells

Since the prototype of a dye-sensitized solar cell(DSSC)was reported in 1991 by M. Gratzel,it has aroused intensive interest over the past decade due to its low cost and simple preparation procedure.The typical cell consists of a dye-coated mesoporous nanocrystalline TiO_2 film sandwiched between two transparent electroldes.A liquid electrolyte,traditionally containing the trioidide/iodide redox couple,fills the pores of the mesoporous nanocrystalline TiO_2 film and contacts the nanoparticles.Photoexcite...     

国内外软饮料工业的现状与趋势

着重介绍国内外软饮料工业的现状与发展趋势,并就国内软饮料工业存在的某些问题,提出了一些看法。     

软阴影算法及实现

提出了一个实时软阴影算法。首先以光源为视点生成包含场景深度信息的＂阴影映射图＂,然后从观察者视点将场景渲染到一个屏幕纹理缓冲中,进而对此纹理采用percentage closer filtering（PCF）策略进行反走样,最后采用高斯滤波对阴影进行模糊处理。该算法不仅得到了较好的软阴影效果,并且也有较好的实时性,可适应实时动态变化场景的需求。     

Inline method of droplet and particle size distribution analysis in dilute disperse systems

In the present article a measurement method of particle size distributions (PSD) in industrial installations which use a dispersed phase of low concentration (like spray dryers or spray scrubbers) is introduced. A new type of inline-measurement system has been developed and designed to work in spray drying conditions. A standard digital camera is used to record shadows of flowing particles inside the spray drying chamber. Collected images were analyzed by a newly developed software which recognizes particles only in the focus area and eliminates several types of artifacts. The constructed prototype of the PSD inline-analyzer was installed and used to monitor large laboratory scale spray dryer. All data collected by the designed system during the spray drying experiments were compared with data measured with an offline reference system to show accuracy of the new measurement technique.     

非规则外形内聚颗粒模型的构建及其破碎能分析

考虑矿石的非规则外形、内部不同组分及其之间的力学特性,基于离散元数值分析方法、离散元软件EDEM及其二次开发,构建一种多尺度非规则外形内聚颗粒模型;利用颗粒模型在剪切挤压破碎机中对矿石破碎过程的破碎能耗特性进行分析。结果表明,破碎能与剪切挤压破碎机的加载方式有密切关系,在内锥振动频率一定时,外锥的转速越快,破碎能越大;外锥转速一定时,内锥振动频率越高,破碎能越大;矿石破碎越多,破碎能越大;矿石破碎速度越大,破碎能增长越快;矿石破碎速度减少,破碎能随之减小。     

Towards realistic characterisation of chemical reactors: An in-depth analysis of catalytic particle beds produced by sieving

Optimization of large-scale fixed particle bed catalytic reactors requires extensive insight into the multi-scale bed structure, even down to the micrometre scale. Theoretical studies of chemical reactors provide a time- and cost-effective means to supporting the optimisation process. However, they rely on simplified assumptions for the particles, e.g. homogeneous perfect spheres. In practise, the preparation of catalytic particles cannot attain this level of uniformity. Typical preparation techniques, such as sieving, are conducted with the aim of obtaining particle size distributions within a pre-defined range, governed by the sizes of the sieves. However, such methods offer limited control in the actual particle sizes and shapes. This paper evaluates the impact of sieving on the resulting particles and overall structural morphology of catalytic beds. The bed structure is quantified using micro-focus computed tomography (µ-CT), enabling the non-destructive examination and analysis of over 150 thousand particles, in terms of particle size, shape, uniformity, and interparticle porosity. Furthermore, the chemical performance of the resulting beds is compared. The detailed characterisation achieved paves the way for the evolution of more rigorous computational models coupling intricate, localised hydrodynamics with realistic chemical processes. Validation of such models at the lab-scale will accelerate the development of more accurate large-scale models.     

Three-dimensional imaging of human stem cells using soft X-ray tomography

Three-dimensional imaging of human stem cells using transmission soft X-ray tomography (SXT) is presented for the first time. Major organelle types—nuclei, nucleoli, mitochondria, lysosomes and vesicles—were discriminated at approximately 50 nm spatial resolution without the use of contrast agents, on the basis of measured linear X-ray absorption coefficients and comparison of the size and shape of structures to transmission electron microscopy (TEM) images. In addition, SXT was used to visualize the distribution of a cell surface protein using gold-labelled antibody staining. We present the strengths of SXT, which include excellent spatial resolution (intermediate between that of TEM and light microscopy), the lack of the requirement for fixative or contrast agent that might perturb cellular morphology or produce imaging artefacts, and the ability to produce three-dimensional images of cells without microtome sectioning. Possible applications to studying the differentiation of human stem cells are discussed.     

Linear systems analysis of kinetic behaviors of calcium ion channel gating on the biological membrane by an allosteric model

Linear system analysis was applied to calcium channel gating on the biological membrane. The conformational changes of calcium channel gating were expressed by an allosteric enzyme model composed of four subunits with corresponding voltage sensor molecules. The rate constants for the channel states transitions were obtained from reported biological experiments and simulation. The linear system analysis disclosed that the system is unstable and uncontrollable. Combinations of each input site and output of the channel gating state for the impulse responses and the singular values of the system showed that the potency of any particular input site for evoking impulse responses at any particular channel state and singular value is not equivalent among the channel states but favor for large numbers of voltage sensors and open channel states. Allosteric effects for modifying the concerted cooperative properties of the calcium channel have a significant influence on the singular values of the system. System optimization improved the system properties of the calcium channel and will be available for evaluating the economical channel gating of the biological membrane and artificial membrane. Received 25 May 1998     

Process identification using a new component analysis model and particle swarm optimization

A novel component analysis model is proposed to identify the mixed process signals which are frequently encountered in the statistical process control (SPC) and engineering process control (EPC) practice. Based upon one of existing state-of-the-art evolutionary algorithms, called particle swarm optimization (PSO), the proposed model provides a solution (i.e., demixing matrix) by maximizing the determinant of the corresponding second-order moment (variance–covariance) matrix of the reconstructed signals. Then, the estimated demixing matrix is used to separate mixed signals arising from several original process signals. The process signals considered in this paper include inconsistent variance series, autoregressive (AR) series, step change, and Gaussian noises in the process data. In practice, most of industrial manufacturing processes can be well characterized by a mixture of these four types of data. By following the proposed model, the blind signal separation framework can be cast into a nonlinear constrained optimization problem, where only the demixing matrix appears as unknown. Several illustrative examples involving linear mixtures of the process signals with different statistical characteristics are demonstrated to justify the new component analysis model.     

海洋软管增强层的选择及结合方式

当前输油管道软管的应用越来越广,尤其是陆上石油开采日趋贫乏,海庆石油开采比重将越来越大,势必将对海洋用软管的需求不断加大。而对海洋软管技术要求也不断提高,其中大多是针对软管内的增强层所提出的。论述了海洋软管增强层的结构形式、技术要求、材质选择等几方面内容,考察了不同增强层对海洋软管耐压性、耐蚀性、屈挠性、粘合性等指标的影响。     

光面爆破在松软破碎岩体中的应用

本文结合工程实际对松软破碎岩体条件下的爆破技术原理进行了探讨,并总结了该条件下的光面爆破参数设计和施工工艺。     

Aspects of Modeling and Computer Simulation of Soft Tissues: Applications to Arterial Walls

For treating arterial stenosis, caused by e.g. artherosclerotic plaque, the so‐called balloon‐dilation (c.f. angioplasty) is employed in most cases. Herein, high internal pressure (3‐12 bar) is applied to the infected artery. During this process damage effects are induced in the arterial wall which cause the arterial lumen to remain increased after removing the balloon. Therefore, computer simulations of arterial walls require the material modeling of these damage effects. In this paper the anisotropic damage model introduced in Balzani, Schröder and Gross [3], see also Balzani, Schröder and Gross [4], is extended in order to obtain a damage model providing a referential damage state different from the referential deformation state. This is necessary because the artery is assumed to be undamaged for deformations within the physiological range. In this we consider a numerical example wherein an artery is overstretched in order to give an indication of the performance of the model. For this purpose the proposed damage model is applied to the polyconvex stored energy introduced in Schröder and Neff [14].     

玫瑰花型氧化锌的软溶液合成及其发光特性

以硝酸锌和HMT为原料、乙二醇为分散剂、三乙醇胺为表面活性剂合成球形氧化锌晶粒,然后将其引入0.02mol·L-1的HMT溶液里,95℃的条件下进行长达3天的表面修饰,成功地制备出具有独特结构的玫瑰花形氧化锌晶粒。XRD、SEM以及荧光分光光度计的分析结果表明:经修饰获得的玫瑰花型氧化锌呈典型的纤锌矿结构,其直径是球形的近三倍(从600nm增长到1700nm),晶粒质量更为完善,且具有优秀的光致发光性能,仅在388nm处显示尖锐的紫外峰。此外,基于两类晶粒的形貌结构特征及反应过程,对其形成机理进行了初步推断。     

溅射FeSiAl合金薄膜的结构及软磁性能

Ｓｅｎｄｕｓｔ合金是制做薄膜磁头和ＭＩＧ磁头的理想材料，本工作用射频溅射法了备了Ｓｅｎｄｕｓｔ成分的ＦｅＳｉＡｌｗ合金薄膜，研究了制备对膜结构和软磁性能的影响，并对其机理进行了讨论。