Three-dimensional dynamic Green’s functions for a multilayered transversely isotropic half-space

With the aid of a method of displacement potentials, an efficient and accurate analytical derivation of the three-dimensional dynamic Green’s functions for a transversely isotropic multilayered half-space is presented. Constituted by proper algebraic factorizations, a set of generalized transmission–reflection matrices and internal source fields that are free of any numerically unstable exponential terms are proposed for effective computations of the potential solution. Three-dimensional point-load Green’s functions for stresses and displacements are given, for the first time, in the complex-plane line-integral representations. The present formulations and solutions are analytically in exact agreement with the existing solutions given by Pak and Guzina (2002) for the isotropic case. For the numerical computation of the integrals, a robust and effective methodology which gives the necessary account of the presence of singularities including branch points and poles on the path of integration is laid out. A comparison with the existing numerical solutions for multilayered isotropic half-space is made to confirm the accuracy of the numerical solutions.     

Preparation and characterization of functional group gradient surfaces

Functional group gradient surfaces where the density of functional groups changes gradually along the sample length were prepared. The functional group (? COOH, ? CONH₂, and ? OH group) gradient surfaces were produced by the treatment of low-density PE sheets using a corona with gradually increasing power, followed by the graft copolymerization of acrylic acid and subsequent substitution reaction of carboxylic acid groups to amide or hydroxyl groups. The prepared gradient surfaces were characterized by the measurement of water contact angle, FTIR-ATR, and ESCA. The gradient surfaces prepared can be used to systematically investigate the interactions of biological or other species in terms of the surface functional groups and their density of polymeric materials. © 1994 John Wiley & Sons, Inc.     

Separation and sensitive determination of arsenic species (As/As) using the yeast-immobilized column and hydride generation in ICP–AES

Inorganic arsenic was separated using the yeast-immobilized column. Saccharomyces cerevisiae was covalently bonded unto the controlled pore glass, which showed selective preconcentration of As⁵⁺ over As³⁺. The effluent was directly connected to hydride generation (HG) to increase sensitivity. The optimum pH condition for the retainment of arsenic at the column was 7. As⁵⁺ and As³⁺ were completely separated in a few minutes with the flow rate of 1.5 ml min⁻¹. Three molars of nitric acid was adequate both for the elution of As⁵⁺ and hydride generation. The accuracy of the technique was tested with NIST SRMs. Quantitative analysis of arsenic species for herbicide, pesticide, and cigarette were performed, and the results showed good agreements with the suggested values. Yeast-immobilized column-HG-ICP showed a promising future for the arsenic speciation study.     

Aqua dissociation nature of cesium hydroxide

To understand the mechanism of aqueous base dissociation chemistry, the ionic dissociation of cesium-hydroxide in water clusters is examined using density functional theory and ab initio calculations. In this study, we report hydrated structures, stabilities, thermodynamic quantities, dissociation energies, infrared spectra, and electronic properties of CsOH(H(2)O)(n=0-4). With the addition of water molecules, the Cs-OH bond lengthened significantly from 2.46 A for n=1 to 3.08 A for n=4, which causes redshift in Cs-O stretching frequency. It is found that three water molecules are needed for the dissociation of Cs-OH, in contrast to the case of strong acid dissociation which requires at least four water molecules. However, the dissociation for n=3 could be considered as incomplete because a very weak CS em leader OH stretch mode is still present, while that for n=4 is complete since the Cs em leader OH mode no longer exists. This study can be related with hydration chemistry of cations and anions, and extended into the intra- and intercharge-transfer phenomena.     

Acceleration of the diffusion of aqueous CoCl2 solutions in porous-glass membrane in the presence of alkali metal chlorides

The diffusion coefficients of a 0.1 M aqueous solution of cobalt(II) chloride in a porous-glass membrane with a predominant pore radius of 45 nm in the presence of 0.5–3.0 M of lithium, potassium, and cesium chlorides were determined. Specific features of the influence exerted by the type of accompanying electrolytes on the rate of diffusion transport of CoCl₂ were considered.     

Modeling the process of melt solidification on the surface of a material

Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 2, pp. 122–126, March–April, 1992.     

Pulsed-Spray Radiofrequency Plasma Enhanced Chemical Vapor Deposition of CuInS2 Thin Films

Thin films of CuInS₂ were grown on various substrates at a temperature of 523 K from two metal-organic precursors using radiofrequency plasma enhanced chemical vapor deposition (PECVD). Two precursor molecules, with different solubility properties, were dissolved in appropriate solvents and sprayed into the plasma region in the PECVD chamber. The resulting films were examined for atomic composition, growth rate, crystalline orientation, and uniformity. Films made from each precursor differed in thickness, atomic composition, and crystallinity. The uniformity of the film was fairly good from near the edge to the center of the substrate, and evidence for a chalcopyrite-like structure was found in several samples deposited from one of the precursor molecules.