On Anomalous Dissipation in the Plasma of the Dusty Lunar Exosphere

JETP Letters - One of the main features of the dusty plasma compared to the conventional plasma (without charged dust particles is anomalous dissipation that is caused by the charging of dust...     

Electronic interaction between the nitrogen,oxygen, and silicon atoms in the molecules of α-aziridin-1-ylalkoxy(triethyl)silanes

By the PMR method we have established the existence of a high frequency of the inversion of the nitrogen atom in the molecules of -aziridin-1-ylalkoxysilanes. This is due to the fact that the high (because of p-d bonding with the silicon atom) electronegativity of the oxygen atom in the Si-O-C-N system makes possible an interaction between the unshared electron pair of the nitrogen atom and the antibonding orbital of the C-O bond. The latter, in its turn, increases the degree of p-d bonding between the oxygen and silicon atoms (in these compounds the order of the Si-O bond is greater than in the alkoxysilanes).     

Cumulative Clearness Index Frequency Distributions on the Territory of the Russian Federation

Cumulative distributions of clearness index values are constructed for the territory of Russia based on ground observation results and NASA POWER data. The obtained distributions lie close to each other, which means that the NASA POWER data can be used in solar power installations simulation at temperate and high latitudes. Approximation of the obtained distributions is carried out. The values of equation coefficients for the cumulative clearness index distributions constructed for a wide range of climatic conditions are determined. Equations proposed for a tropical climate are used in the calculations, so they can be regarded as universal ones.     

Generalized clearness index frequency curves for the Russian Federation

Actinometric data of World Radiation Data Center and NASA POWER were used to get daily clearness index frequencies for Russia. The results obtained provide the opportunity to estimate more accurately the output of various types of solar power plants. Frequencies determined using the data sources indicated correlate well and differ from universal dependences that were recommended earlier for the entire globe.     

Fast choice of separation conditions for analyses by capillary zone electrophoresis using an information system Xemic

An information system Xemic applicable in analytical chemistry is described and its use in capillary electrophoresis for searching suitable separation conditions is demonstrated. This system is capable to provide suitable separation conditions even for analytes for which no electrophoretic experiments have been published so far. The system works with a database of components of anionic character the analyses of which have been performed, published in reviewed scientific journals, and included into a database created by an expert. Moreover, the system learned to search also in abstracts or complete scientific articles to find articles dealing with the determination of a substance in a given sample matrix. When no experiments have been published so far for a defined substance in a specific matrix, Xemic shows the separation conditions for determination of the substance regardless of the matrix. When no response can be found for the analyte of interest at all, the system Xemic works like an expert in the field and searches chemically similar substances and offers a series of substances the physicochemical properties of which are close to the followed analyte with respect to the behavior in the electric field, and shows working conditions for their analysis. Thus, the analyst puts only the order in the form of a given analyte in a given matrix and obtains a recommendation of a separation system that should enable to perform a successful separation. The system is not rigid and enables the operator to change the importance of individual attributes used in similarity search so as to obtain a broader or narrower group of similar components. With a certain probability the analyte of interest can be successfully analyzed under separation conditions that suited for the analysis of the most similar substances in the given matrix.     

On the Evolution of Resonant Waves in Closed Plasma Systems

The evolution of resonant waves in closed turbulent plasma systems is considered. It is shown that the effect of the system's nonstationarity on the evolution of the resonant waves should be considered together with the nonlinear interactions of the same order. The case for which the plasma-maser effect is significant in the presence of the nonstationarity is investigated.     

Analysis of Phosphorescence Decay in Heterogeneous Systems: Consequences of Finite Excitation Flash Duration

Analysis of phosphorescence lifetimes using the Stern-Volmer equation is a reliable means of determining quencher concentration for a uniform sample. Methods of analysis for heterogeneous systems are based on the assumption that the excitation is produced by a momentary flash. This condition is an idealization because a real flash has a finite duration and a complex time profile. In the case of a heterogeneous quencher concentration, an excitation flash produces different initial intensities and different times of peak intensity from compartments having different concentrations of quencher. We formulated a model to explore the effects of flash duration on the shape of the emission curve obtained from systems in which the heterogeneity is continuous. We developed mathematical models that can be used to recover fitting parameters of continuous distributions of reciprocal lifetimes approximated as rectangular or Gaussian distributions, or an arbitrary histogram. We also formulated a procedure to convert the distribution of reciprocal lifetimes into a volume distribution of quencher concentration. We found that (1) the Stern-Volmer ratio of phosphorescence intensities cannot be employed for interpretation of pulse phosphorometric data in terms of a volume distribution of quencher; (2) shortening the flash duration decreases the difference of initial intensities between compartments having high and low quencher concentration; (3) the parameters of the volume distribution of quencher concentration can be recovered correctly only after taking account of the difference in initial intensities; and (4) calibration of the initial intensities for a given fitting delay and flash function is necessary.     

On the two-phase magnetic state in a CuxZn1−x Cr2Se4 cation-substituted chalcogenide spinel

The region of the concentration magnetic phase transition in a Cu_xZn_1?x Cr₂Se₄ chalcogenide spinel in which the substituted ion concentration x smoothly varies from 0.1 to 0.2 with a step of 0.02 is thoroughly investigated. An anomalous behavior of the Curie temperature is observed. This anomaly is associated with the nucleation of ferromagnetically ordered microregions in the vicinity of Cr ions with an intermediate valence and subsequent long-range magnetic ordering at a critical Cu concentration in the range 0.12<x _c <0.14. The possible coexistence of ferro-and antiferromagnetism in the same temperature range is revealed.     

An analytical solution for steady flow of a Quemada fluid in a circular tube

An analytical solution is obtained for steady flow of Quemada-type fluids in a circular tube driven by a constant pressure gradient. Expressions are derived for velocity distribution and for volumetric flow rate as a function of pressure gradient or wall shear stress.     

Application of Chimera grid to modelling cell motion and aggregation in a narrow tube

A computational scheme using the Chimera grid method is presented for simulation of three‐dimensional motion and aggregation of two red blood cells (RBCs) in a narrow tube. The cells are modelled as rigid ellipsoidal particles; the computational scheme is applicable to deformable fluid‐filled particles. Attractive energy between two RBCs is modelled by a depletion interaction theory and used for simulating aggregation of two cells. Through the simulation, we show that the Chimera grid method is applicable to the simulation of three‐dimensional motion and aggregation of multiple RBCs in a microvessel and microvascular network. Copyright © 2006 John Wiley & Sons, Ltd.