SCDA for 3D lattice gases with repulsive interaction

The selfconsistent diagram approximation (SCDA) is generalized for three-dimensional lattice gases with nearest neighbor repulsive interactions. The free energy is represented in a closed form through elementary functions. Thermodynamical (phase diagrams, chemical potential and mean square fluctuations), structural (order parameter, distribution functions) as well as diffusional characteristics are investigated. The calculation results are compared with the Monte Carlo simulation data to demonstrate high precision of the SCDA in reproducing the equilibrium lattice gas characteristics. It is shown that similarly to two-dimensional systems the specific statistical memory effects strongly influence the lattice gas diffusion in the ordered states. Received 7 August 2002 / Received in final form 22 January 2003 Published online 24 April 2003     

On Some Ricci-Flat Metrics of Cohomogeneity Two on Complex Line Bundles

We construct a family of four-dimensional smooth Ricci-flat Riemann orbifolds of cohomogeneity two which possess the structure of complex line bundles.     

Temperature factor effect on the structure of the separated flow within a supersonic gas stream

The effect of the temperature factor, that is, the ratio of the body temperature to the freestream stagnation temperature, on the structure of the separated flow formed in the presence of a concave corner in a supersonic stream is studied. The strong influence of the temperature factor on the separation zone length and the flow-generated aerodynamic characteristics is established. It is shown that for fairly large deflection angles this flow cannot be described by free interaction, or triple deck, theory.     

Quantum dynamics of single-photon detection

Dynamics of the elementary photoelectric conversion upon interaction of a single-photon mode with a bound electron in a one-dimensional rectangular potential well is considered. The spatial and temporal dynamics of the wave packet corresponding to a free photoelectron is investigated.     

Chemical Mechanisms of Liquid–Liquid and Solid-Phase Extraction of Metal Chelates

Conditions of the liquid–liquid and solid-phase extraction of metal chelates are compared. The analogy and differences in the behavior of chelates and the effect of stability and partition constants on the completeness of the extraction of metals are discussed.     

q←q~(-1)对称的非广延熵描述下的正则玻色子系综

将Abe引入的q q-1对称变形熵应用于玻色子的正则系综,根据最大熵原理和Lagrange乘子法,导出了系统的密度算子,进而在微变形的条件下求出了粒子数算符的期望值及其在高温、低温下的近似值。     

Reflection spectrum of a cholesteric liquid crystal with structural defects

An expression is obtained for the reflection coefficient of circularly polarized light normally incident on the film of a cholesteric liquid crystal with a variable helix pitch. It is shown that, in the case of a single defect (local change in the helix pitch), the spectrum of light reflection from a cholesteric acquires a dip corresponding to the defect mode. New qualitative features appear in the reflection spectrum of a cholesteric with two defects as the distance between them varies.     

Coprecipitation of Naphthol Azosulfonates with Organic Coprecipitants and Its Use in Flow-Injection Analysis

The coprecipitation of azo compounds based on 4-nitrophenyl- and 4-sulfophenyldiazonium naphthol sulfonates as their diphenylguanidinium ion-pair complexes with analogous compounds of naphthalene-2-sulfonic acid and 4-phenylsulfodiazonium is investigated. The optimization of the coprecipitation is considered based on the notions of the driving force of the cocrystallization of impurities. The optical characteristics of colored ion-pair complexes are measured. It is found that the water solubility is decreased most substantially for azosulfonates with hydrophobic nitro groups and with no more than two sulfo groups in different aromatic nuclei, which can lead to a decrease in the detection limit due to preconcentration by coprecipitation, which stimulates the thermodynamic flux of concentrate elution. Coprecipitation is combined with flow-injection analysis in the on-line mode, and new procedures are developed for determining naphthol sulfonates and related azo compounds with the detection limit equal to 0.003–0.006 mg/50 mL.