基礎講座 電気泳動(Electrophoresis)

The development of novel materials is a fundamental focal point of chemical research; and this interest is mandated by advancements in all areas of industry and technology. A good example of the synergism between scientific discovery and technological development is the electronics industry, where discoveries of new semiconducting materials resulted in the evolution from vacuum tubes to diodes and transistors, and eventually to miniature chips. The progression of this technology led to the development * To whom correspondence should be addressed. B.L.C.: (504) 2801385 (phone); (504) 280-3185 (fax); bcushing@uno.edu (e-mail). C.J.O.: (504)280-6846(phone);(504)280-3185(fax);coconnor@uno.edu (e-mail). 3893 Chem. Rev. 2004, 104, 3893−3946

http://depa.fquim.unam.mx/amyd//archivero/FidelmarLechugaSanabria_4940.pdf

Recent advances in the liquid-phase syntheses of inorganic nanoparticles.

1: Magnetic Particles: Preparation, Properties and Applications: M. Ozaki. 2: Maghemite (gamma-Fe2O3): A Versatile Magnetic Colloidal Material C.J. Serna, M.P. Morales. 3: Dynamics of Adsorption and Oxidation of Organic Molecules on Illuminated Titanium Dioxide Particles Immersed in Water M.A. Blesa, R.J. Candal, S.A. Bilmes. 4: Colloidal Aggregation in Two-Dimensions A. Moncho-Jorda, F. Martinez-Lopez, M.A. Cabrerizo-Vilchez, R. Hidalgo Alvarez, M. Quesada-PMerez. 5: Kinetics of Particle and Protein Adsorption Z. Adamczyk.

Surface and Colloid Science

This chapter introduces the finite element method (FEM) as a tool for solution of classical electromagnetic problems. Although we discuss the main points in the application of the finite element method to electromagnetic design, including formulation and implementation, those who seek deeper understanding of the finite element method should consult some of the works listed in the bibliography section.

Introduction to the Finite Element Method

Applied Numerical Analysis. By C.F. Gerald. Pp. xii, 340. £3·60. 1970. (Addison-Wesley.)

The electrical interaction of a system containing multiple, charged, rigid spherical particles of arbitrary orientation and size is analyzed theoretically. The equation governing the spatial variation of electrical potential is solved by a boundary integral method, and the electrical free energy of the system under consideration is evaluated. Several approximate analytical expressions for the electrical free energy are presented. We show that pairwise addition will, in general, overestimate the electrical free energy, except that when the electrical double layer around a particle is thin, it is approximately correct. Since the electrolyte concentration at which coagulation occurs is usually high, the classic analysis based on the interaction between two particles is representative of a system containing multiple particles and leads to reasonable results.

Electrical interaction of a system containing multiple charged rigid spherical particles

Assuming that intercellular messages are a requisite to microbial flocculation, we show that, on the basis of the effectiveness factor, the diffusional resistance in a biofloc can be advantageous to an autocatalytic reaction. In other words, the metabolic efficiency of flocculated microbes can be higher than that of the dispersed microbes. Therefore microbes tend to flocculate in certain circumstances.

Diffusion-controlled autocatalytic reaction: A possible driving force for microbial flocculation

The spatial distribution of colloidal particles in a confined space is frequently a key issue to many phenomena of practical significance. This problem is investigated by considering the distribution of colloidal particles in a spherical cavity under the conditions of relatively large cavities, low cavity and colloidal particles potentials, and low monovalent electrolyte and colloidal concentrations. The analytical expression for the particle-cavity pair interaction energy is derived under various surface conditions. The results obtained are used to evaluate the direct correlation functions in the hypernetted chain approximation employed for the resolution of an Ornstein-Zernike equation. For a fixed particle number concentration at the center of a cavity, we make the following conclusions: (i) the spatial distribution of particles increases in an oscillatory manner with the distance away from the cavity surface, (ii) increasing the particle-cavity pair interaction energy has the effect of reducing the free space of particles inside a cavity, and (iii) the greater the pair interaction energy between two particles, the higher the average concentration of particles.

Distribution of colloidal particles in a spherical cavity.

Translation of two rigid spheres perpendicular to their line-of-centers and normal to a plate

The diffusiophoresis of a pH-regulated polyelectrolyte (PE) along the axis of a charged nanopore having nonuniform cross section is modeled, aimed with improving the performance of a nanopore-based sensing device for single biomolecules such as DNAs and proteins. Previous analysis based on a rigid particle of constant charge density in a solution containing binary ionic species is extended to a porous, pH-regulated PE in a solution containing multiple ionic species so that the conditions considered are much closer to reality. The behavior of the PE under various conditions is simulated by varying its charge, relative size, position in the nanopore, the solution pH, and the background salt concentration. We show that the PE translocation velocity can be regulated by the pore width and its charged conditions. In particular, both the magnitude and the direction of the translocation velocity can be adjusted.

Jyh-Ping Hsu

Papers

Electrical interaction of a system containing multiple charged rigid spherical particles

Diffusion-controlled autocatalytic reaction: A possible driving force for microbial flocculation

Distribution of colloidal particles in a spherical cavity.

Translation of two rigid spheres perpendicular to their line-of-centers and normal to a plate

Diffusiophoresis of a pH-regulated polyelectrolyte in a nanopore of nonuniform cross section