The scattering from generalized Cantor fractals

We consider a fractal with a variable fractal dimension, which is a generalization of the well known triadic Cantor set. In contrast with the usual Cantor set, the fractal dimension is controlled using a scaling factor, and can vary from zero to one in one dimension and from zero to three in three dimensions. The intensity profile of small-angle scattering from the generalized Cantor fractal in three dimensions is calculated. The system is generated by a set of iterative rules, each iteration corresponding to a certain fractal generation. Small-angle scattering is considered from monodispersive sets, which are randomly oriented and placed. The scattering intensities represent minima and maxima superimposed on a power law decay, with the exponent equal to the fractal dimension of the scatterer, but the minima and maxima are damped with increasing polydispersity of the fractal sets. It is shown that for a finite generation of the fractal, the exponent changes at sufficiently large wave vectors from the fractal dimension to four, the value given by the usual Porod law. It is shown that the number of particles of which the fractal is composed can be estimated from the value of the boundary between the fractal and Porod regions. The radius of gyration of the fractal is calculated analytically.Comment: 8 pages, 4 figures, accepted for publication in J. Appl. Crys

Опыт палинологических исследований в нефтяной геологии

The authors present the directions for palynological research: detailed (zonal) palynostratigraphy for clarifying the age and correlation of reservoirs; palynological facial analysis for reconstruct the position of the ancient coastline; determination of the degree of catagenesis of organic matter using the palynomorphs color index for assessing the oil and gas generation potential of terrigenous sediments of the Perm region.Авторы представили направления палинологических исследований: детальная (зональная) палиностратиграфия для уточнения возраста и корреляции продуктивных пластов; палинофациальный анализ для реконструкции положения древней береговой линии; определение степени катагенеза органического вещества по цветовому индексу палиноморф для оценки нефтегазогенерационного потенциала терригенных отложений территории Пермского края

Sorptive and Separation Properties of Ultrafiltration Membranes on the Basis of Sulfonate-Containing Polyamide with Respect to Bovine Serum Albumin

Investigation of sorption of bovine serum albumin in the static mode and in ultrafiltration conditions by membranes produced from statistic copolymers of aromatic polyamides synthesized by polycondensation of the sodium salt of 4, 4/-diaminodiphenylamine-2-sulfo-acid and m-phenylenediamine in various ratios with chloroanhydride of isophthalic acid has been carried out. Interconnection has been established between the charge of protein macromolecules, concentration of fragments containing ionic groups in the aromatic polyamide and sorptive, separation and transport characteristics of membranes on its basis. It has been shown that dominant forces that determine membrane/protein interaction in the systems under consideration are coulomb forces, but the contribution of hydrophobic interactions is also significant. The results of mathematical processing of experimental data indicate that there is a good compliance of sorption isotherms with Langmuir’s model. Depending on the concentration of fragments containing ionic groups in the polyamide and pH of the solution, the calculated values of maximum sorption in sorbent/sorbate systems under consideration vary in the range of 0.028 to 0.338 mg/cm2. Dynamic investigations have shown that selectivity of the membranes is 85 to 98%. To assess the sorptive activity of the membranes in the course of ultrafiltration, indicators of sorption and sorptive losses calculated on the basis of the ratio of the change of mass content of protein in the process of filtration to the initial value have been used. Depending on the material used to produce the membrane and pH of the solution being filtered, sorptive losses range from 5 to 33%. Their minimum value is observed when pH is higher than the isoelectric point of the protein, i.e. in the field where protein macromolecules and the surface of the membrane have like charges

Dynamical Casimir Effect in a one-dimensional uniformly contracting cavity

We consider particle creation (the Dynamical Casimir effect) in a uniformly contracting ideal one-dimensional cavity non-perturbatively. The exact expression for the energy spectrum of created particles is obtained and its dependence on parameters of the problem is discussed. Unexpectedly, the number of created particles depends on the duration of the cavity contracting non-monotonously. This is explained by quantum interference of the events of particle creation which are taking place only at the moments of acceleration and deceleration of a boundary, while stable particle states exist (and thus no particles are created) at the time of contracting.Comment: 13 pages, 4 figure