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Abstract: The equilibrium distributions of the misfit dislocation density ?(z) and elastic stresses e(z) are calculated along the direction of the epitaxial growth of the metamorphic InAlAs/GaAs(001) layer with higher In content (to 87 mol %) and various profiles of varying the composition: step, linear, and root. The calculations are performed using the method based on iteration searching for the minimum total energy of the system. It is shown that the largest differences between various constructions of the buffer layer are observed in the character of distributions ?(z), rather than e(z). Unlike the traditional constructions with a step and linear gradients of the composition, which are characterized by a quite homogeneous distribution of misfit dislocations, in a buffer layer with a root composition gradient, the main part of such dislocations is concentrated in the lower part of the layer near the heteroboundary with a GaAs substrate, and their density sharply decreases by more than one order of value along the layer thickness, achieving the value minimum for all abovementioned constructions. In spite of the fact that the important effect of interacting the dislocations to each other is not taken into account in this work, the calculations enable us to establish the main peculiarities of the distributions ?(z) and e(z) in various metamorphic buffer InAlAs layers, which were observed experimentally before. Thus, this approach can be effectively used when designing optimal constructions of the device metamorphic heterostructures.

An IR photoreflectance (PR) study of two-dimensional nanoheterostructures based on InSb was performed by using Fourier-transform IR photomodulation spectroscopy. The studied structures, including InSb/Al_xIn_1−xSb quantum wells (QWs) and type-II nanostructures with monolayer-thick InSb insertions within bulk InAs layers, were grown via molecular beam epitaxy on GaAs (001) and InAs (001) substrates, respectively. The PR spectra of the InSb/Al_xIn_1−xSb heterostructures exhibited a series of signals from the QWs, including the spin-orbit split band, as well as the Al_xIn_1−xSb layers, which enabled control of the barrier height and composition. A comparison of the experimental results with calculations made by the effective mass approximation technique was used to identify several optical transitions observed within the QWs, including those related to the excited states not visible in the photoluminescence spectra. For the InSb/InAs monolayer nanostructures, an analysis of the PR spectra features allowed for determination of their energy spectrum, internal electric field value, and localization energy of holes up to room temperature.

The kinetics of fracture and deformation of the standard aluminum alloy AD1 and a similar alloy subjected to severe plastic deformation by high-pressure torsion under conditions of high-speed erosion has been investigated. It has been shown that, with an increase in the loading rate, the fraction of the brittle component on the fracture surface of the standard material, as well as the thickness of the damaged layer, increases more significantly than that for the material after the severe plastic deformation by high-pressure torsion. A relationship of the surface roughness of the material after the erosion with the loading rate and the thickness of the erosion-damaged layer has been established.

The photoreflectance spectra of n-InSb layers were measured using photomodulation Fourier transform infrared spectroscopy. The samples were grown by molecular beam epitaxy on heavily doped n+-InSb(001) substrates annealed under different conditions. The strength of the near-surface electric field was determined from the period of the Franz–Keldysh oscillations observed in the photoreflectance spectra. It was noted that the strength of the electric field increases during a long-term storage of the samples in air. The treatment of n-InSb layers in a 1M aqueous solution of Na2S led to an increase in the measured field. Previously, it was shown that, after this treatment, the surface Fermi level is shifted deep into the conduction band and, probably, does not depend on the conditions and time of the preliminary storage of the samples. With the use of passivation in Na2S, the optical method developed in this study allows for the contactless measurement of the concentration of electrons in n-InSb homoepitaxial layers.

Some methodological features of the airborne gravity surveys of Russia’s territory at the latitude of 60° from Arkhangelsk to Kamchatka are described. The results of these surveys are presented. The data obtained from gravimeters installed aboard an aircraft laboratory are compared with EGM2008 and EIGEN-6C3, the state-of-the-art global Earth gravity field models. It is shown that the present-day models have the highest errors near the coastal tectonic structures of the Kamchatka Peninsula.

Abstract: A method for minimization of Moore finite automata based on the operation of gluing two states and on the represention of a finite automaton in the form of a transition list is considered. Conditions of the identical operation and deterministic behavior of the finite automaton obtained as a result of gluing two states are presented. Cases of formation of wait states as a result of state gluing are considered. Algorithms for minimization of the number of internal states, transition routes, and input variables of Moore finite automata are described. Features of application of the proposed approach are reported.

Abstract: Considered is a new method of remote derivation of the land surface temperature (LST) T s using data of nonsimultaneous measurements of the SEVIRI/Meteosat-9 instrument in channels of transparency windows of 10.5–12.5 μm in the case of the cloudiness absence in the field of instrument. The method is the combination of two well-known algorithms of the subject processing of satellite data. It enables to derive T s without the involvement of data on the values of the land emissivity at sounding stations. Experiments on the processing of SEVIRI actual data of some autumn days of 2008, as well as a comparison of the results with independent satellite estimations of T s , confirm the operability and efficiency of the proposed method. The possibility of detailed description of the diurnal course of LST on the basis of SEVIRI data using the proposed method of T s estimation is analyzed.

Abstract: Specific features of the technique of airborne gravity surveys in the Arctic are considered. The main requirements for aerogravimetric complexes used for such surveys and for reference GPS stations located at high latitudes are formulated, as well as the conditions necessary for converting an aircraft into an aircraft-laboratory. Specific features of the planning of measurements of aerogravimetric profiles in the Arctic are described. The need in the operations necessary for the rapid estimation of the results is substantiated. The obtained regional gravimetric map on a 1:200000 scale is presented as an example.

Abstract: The problem of construction of large-capacity comparators from programmable logic integrated circuits (PLICs) is discussed. A method for synthesizing large-capacity comparators with hierarchical pyramidal structures is proposed. This method is compared with two known (parallel and sequential) methods and two methods of the Altera MAX+PLUSII computer-aided design program package. The results of experimental studies have shown that, in the design of 64-bit comparators, the proposed method makes it possible to decrease the implementation cost on average by a factor of 1.09 to 1.54 and increase the processing speed on average by a factor of 3.79 to 7.17, depending on the family of PLICs.

Chemoinformatics approaches open new opportunities for computer-aided design of new efficient metal binders. Here, we demonstrate performances of ISIDA and COMET software tools to predict stability constants (log K) of the metal ion/organic ligand complexes in solution and to design in siliconew molecules possessing desirable properties. The predictive models for log Kof lanthanides complexation in water have been developed. Some new uranyl binders based on monoamides and on phosphoryl-containing podands were suggested theoretically, then synthesized and tested experimentally. Reasonable agreement between experimental uranyl distribution coefficients and theoretically predicted values has been observed.

Abstract: The inverse problems of determining the source and coefficient of an elliptic equation in a rectangle are studied. Additional information on the solution to the direct problem (overdetermination) is the trace of its solution on an interval inside the rectangle. Sufficient existence and uniqueness conditions (global) are derived for the inverse problems. The study is performed in the class of continuously differentiable functions whose derivatives satisfy a H�lder condition.

Abstract: A method of determination of atmospheric dynamic characteristics from the data of remote sensing from a geostationary satellite is described. The method is based on the use of inhomogeneities in the concentration field of a conservative additive as tracers and on the application of correlation-extreme algorithms. Unlike the common methods used abroad, this method is able to determine not only the vector field of wind velocity but also the coefficient of turbulent diffusion and vorticity. Results of computations of the fields of the horizontal component of wind velocity and the effective coefficient of horizontal mesoscale turbulent diffusion from the Meteosat-8 SEVIRI water-vapor channel data are presented. It is shown that the average values of the effective coefficient of mesoscale horizontal turbulent diffusion in the areas with a predominantly turbulized air-mass motion are 1.5 times greater than in the areas where a laminar motion dominates. Specific features of the calculated values of the upper-troposphere dynamic characteristics in different stages of the North Atlantic TC Helene (September 2006) are analyzed.

Substructural Molecular Fragments (SMF) method was applied for computer-aided design of new compounds potentially possessing high anti-HIV activities: tetrahydroimidazobenzodiazepinone (TIBO) derivatives and 1-[2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (HEPT) derivatives. Using available experimental data, the SMF method was first applied to build QSAR models based on fragment descriptors (atom/bond sequences and “augmented atoms”). The focused virtual combinatorial libraries containing 891 TIBO derivatives and 2640 HEPT derivatives were then generated systematically attaching selected substituents to corresponding Markush structures. Finally, a screening of those libraries using developed QSAR models led to several hits potentially possessing high anti-HIV activity.

This paper discusses a method of microscanning for compensating the inhomogeneity of the parameters of the elements of thermal-vision detectors. It is shown that the compensation quality depends on the number of elements of the detector array, the presence of nonworking elements, and the SNR. It is independent of the nonuniformity of the scene and of the degree of inhomogeneity of the detector. The dependences of the quality of the inhomogeneity compensation are obtained for arrays with 288×384 and 128×128 elements. © 2005 Optical Society of America

This paper is devoted to computer-aided design of new extractants of the uranyl cation involving three main steps:  (i) a QSPR study, (ii) generation and screening of a virtual combinatorial library, and (iii) synthesis of several predicted compounds and their experimental extraction studies. First, we performed a QSPR modeling of the distribution coefficient (logD) of uranyl extracted by phosphoryl-containing podands from water to 1,2-dichloroethane. Two different approaches were used:  one based on classical structural and physicochemical descriptors (implemented in the CODESSA PRO program) and another one based on fragment descriptors (implemented in the TRAIL program). Three statistically significant models obtained with TRAIL involve as descriptors either sequences of atoms and bonds or atoms with their close environment (augmented atoms). The best models of CODESSA PRO include its own molecular descriptors as well as fragment descriptors obtained with TRAIL. At the second step, a virtual combinatorial library of 2024 podands has been generated with the CombiLib program, followed by the assessment of logDvalues using developed QSPR models. At the third step, eight of these hypothetical compounds were synthesized and tested experimentally. Comparison with experiment shows that developed QSPR models successfully predict logDvalues for 7 of 8 compounds from that “blind test” set.

The results of a computational experiment with a neural-net model simulating the effect of the chemical composition on the plastic properties of ÉP-450 steel are presented. It is shown that computer-aided development of reactor steel with prescribed properties is, in principle, possible.

Substructural molecular fragments (SMF) method Solov'ev, V. P.; Varnek, A.; Wipff, G. J.Chem. Inf. Comput. Sci.2000, 40, 847−858 was applied to assess anti-HIV activity for large data sets for three families of compounds:  1-2-hydroxyethoxy)methyl-6-(phenylthio)thymine (HEPT) derivatives, tetrahydroimidazobenzodiazepinone (TIBO) derivatives, and cyclic urea (CU) derivatives. The SMF method uses 49 types of topological descriptors (atom/bond sequences and “augmented atoms”) which, being coupled with 3 linear and nonlinear fitting equations, allows the user to generate up to 147 structure−property models. For each family of compounds, the modeling was performed on several training sets followed by the validation calculations where three best fit models were applied. Calculated activities well reproduce available experimental data. On the basis of the “optimal” molecular fragments, the focused combinatorial library containing 252 virtual HEPT derivatives has been generated. Its filtering led to several hits potentially possessing anti-HIV activity.

A sample of structurally characterized 10000 complexes (X-ray diffraction data) was carefully selected from available databases for analysis of coordination numbers (CNs) of their central atoms (complexing agents). The coordination numbers of various chemical elements are tabulated for their different oxidation numbers (ONs). Variations in CN with the ordinal number of an element in the Periodic Table were followed. A general distribution of the sample complexes over the CNs of the central atom, as well as their distributions for particular ONs, is displayed. References to particular coordination compounds are given for extreme and very uncommon CNs of a central atom with different ONs. A general pattern of the observed variations in the CN of chemical elements can be useful for predicting the properties of complexes, constructing their stability models, designing compounds with rich and unique properties, and developing retrieval and graphic tools for chemical databases.

The Substructural Molecular Fragments method (Solov'ev, V. P.; Varnek, A. A.; Wipff, G. J. Chem. Inf. Comput. Sci.2000, 40, 847−858) was applied to assess stability constants (logK) of the complexes of crown-ethers, polyethers, and glymes with Na, K, and Csin methanol. One hundred forty-seven computational models including different fragment sets coupled with linear or nonlinear fitting equations were applied for the data sets containing 69 (Na), 123 (K), and 31 (Cs) compounds. To account for the “macrocyclic effect” for crown-ethers, an additional “cyclicity”descriptor was used. “Predicted” stability constants both for macrocyclic compounds and for their open-chain analogues are in good agreement with the experimental data reported earlier and with those studied experimentally in this work. The macrocyclic effect as a function of cation and ligand is quantitatively estimated for all studied crown-ethers.

The Substructural Molecular Fragments method (Solov'ev, V. P.; Varnek, A. A.; Wipff, G. J. Chem. Inf. Comput. Sci. 2000, 40, 847−858) was applied to assess stability constants (logK) of the complexes of crown-ethers, polyethers, and glymes with Na⁺, K⁺, and Cs⁺ in methanol. One hundred forty-seven computational models including different fragment sets coupled with linear or nonlinear fitting equations were applied for the data sets containing 69 (Na⁺), 123 (K⁺), and 31 (Cs⁺) compounds. To account for the “macrocyclic effect” for crown-ethers, an additional “cyclicity”descriptor was used. “Predicted” stability constants both for macrocyclic compounds and for their open-chain analogues are in good agreement with the experimental data reported earlier and with those studied experimentally in this work. The macrocyclic effect as a function of cation and ligand is quantitatively estimated for all studied crown-ethers.

The half-width of the spectrum of Raman scattering (RS) of the first order of a diamond single crystal grown in a nickel-free system containing nitrogen getters is identical to all growth sectors (1.69 ± 0.02 cm−1). The sectorial inhomogeneity is not reflected in the transmission spectra and birefringence of this crystal. The nitrogen concentration is 4·1017cm−3. For different growth sectors of the diamond crystal grown in the Ni–Fe–C system, the half-width of the Raman line varies from 1.74 to 2.08 cm−1, differences in the transmission spectra and birefringence are observed, and photoluminescence is revealed. The concentration of nitrogen in the growth sectors {001} is 1.6·1019cm−3, the content of nickel is estimated to be at a level of 1019cm−3, and the content of nitrogen in the {¯111} sectors is 4·1019cm−3.

A substructural molecular fragment (SMF) method has been developed to model the relationships between the structure of organic molecules and their thermodynamic parameters of complexation or extraction. The method is based on the splitting of a molecule into fragments, and on calculations of their contributions to a given property. It uses two types of fragments:  atom/bond sequences and “augmented atoms” (atoms with their nearest neighbors). The SMF approach is tested on physical properties of C2−C9alkanes (boiling point, molar volume, molar refraction, heat of vaporization, surface tension, melting point, critical temperature, and critical pressures) and on octanol/water partition coefficients. Then, it is applied to the assessment of (i) complexation stability constants of alkali cations with crown ethers and phosphoryl-containing podands, and of -cyclodextrins with mono- and 1,4-disubstituted benzenes, and (ii) solvent extraction constants for the complexes of uranyl cation by phosphoryl-containing ligands.

A substructural molecular fragment (SMF) method has been developed to model the relationships between the structure of organic molecules and their thermodynamic parameters of complexation or extraction. The method is based on the splitting of a molecule into fragments, and on calculations of their contributions to a given property. It uses two types of fragments:  atom/bond sequences and “augmented atoms” (atoms with their nearest neighbors). The SMF approach is tested on physical properties of C2−C9 alkanes (boiling point, molar volume, molar refraction, heat of vaporization, surface tension, melting point, critical temperature, and critical pressures) and on octanol/water partition coefficients. Then, it is applied to the assessment of (i) complexation stability constants of alkali cations with crown ethers and phosphoryl-containing podands, and of β-cyclodextrins with mono- and 1,4-disubstituted benzenes, and (ii) solvent extraction constants for the complexes of uranyl cation by phosphoryl-containing ligands.

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The effect of individual and multicomponent additives of sodium chloride, iron chloride, sodium nitrate and 1-methyl-2-pyrrolidone on the interfacial distribution of thiophene in the systems polyethylene glycol 1500 (PEG-1500) - hexane - water and polyethylene glycol 8000 (PEG-8000) - hexane - water has been studied in this investigation. It was found that in most cases, the introduction of a small amount of individual and joint additives increases the extraction of thiophene from the organic phase to the aqueous.

In this work, we studied the interphase distribution of a number of polybasic carboxylic acids, in particular, malic, succinic, glutaric, citric, ascorbic and tartaric in two-phase aqueous systems polyethylene glycol-1500 (PEG-1500) - sodium sulfate - water and PEG-1500 - ammonium sulfate - water. Using the spectrophotometric method of analysis, quantitative characteristics (interfacial distribution and degree of recovery) of the extraction of carboxylic acids were determined. In conclusion, it was found that the considered two-phase aqueous systems are promising in the process of extraction of polybasic carboxylic acids. In particular, the system polyethylene glycol 1500 - sodium sulfate - water has effective extraction properties for succinic malic and ascorbic acids. On the other hand, depending on the composition of the extraction systems, the quantitative characteristics for citric, glutaric and tartaric acids practically do not differ.

The products of matrix reactions of magnesium atoms and clusters with carbon dioxide, ethylene, and their mixtures have been characterized by the IR and UV−vis techniques and ab initio methods of quantum chemistry. The structures, binding energies, and vibrational frequencies for the MgCO2, Mg(C2H4)n (n = 1,2), and MgC2H4CO2 complexes are reported. We conclude that in the metastable MgCO2 species magnesium is bound to both oxygen atoms forming the four-member ring. The structures of Mg(C2H4)2 and MgC2H4CO2 correspond to the five-member cycles, and magnesium is responsible for the formation of chemical bonds between the ligands.

Theoretical results on the heat transfer in combustion-product filtration in the rock-collapse zone behind a borehole-damaged coal bed are outlined. A sufficiently simple engineering solution of the problem is obtained by means of an equivalent heat-conduction equation, and the limiting temperatures corresponding to different parameter values are analyzed.

The main difficulties in conventional argon-arc welding methods of high-temperature nickel-base alloys are caused by their elevated capacity for crack formation and the-impossibility in some cases of obtaining joints with a strength equal to me strength of me base metal. Welding such materials by beam methods (laser and electron-beam) presents special interest. This paper presents the results of an investigation of welded joints of high-temperature alloys obtained by laser welding.

By a matrix method of successive approximations, using perturbation theory, the complete set of force constants has been calculated for the free anions WO,2- and MoO42- and for systems MEO42-(M = Na2+, Li2+, Pb2+,Sr2+, Ca2+; E = W, Mo) on the basis of known frequencies of IR and Raman spectra of the corresponding individual melts. Analysis of the results indicates an increase in the force constants of E-O bond stretching and the bending force constants for AD”- and MoO42- with increasing specific charge of the cation in a field of singly or doubly charged cations.

Measured frequencies from pure nitrate liquids have been used to calculate the force constants for the nitrate ion and the M+-NO3- systems (M+ = Li+, Na+, K+, Rb+, and Cs+) by a matrix successive-approximation method based on perturbation theory in dependent coordinates. The valency force constants Kq for the N-O bonds are increased by comparison with free NO3-. The N-O bond strengthening is not adequately explained by cation-anion interaction because there is electron-density transfer mainly by the p mechanism within the NO3-. Correction for the vibrational parameters of the interacting particles confirms the previously demonstrated acid-base mechanism for the cation-anion interaction in liquids containing nitrate.

Conclusions The energy-momentum problem for the gravitational field in general relativity has been a stumbling block for theoreticians for more than six decades. During this time different authors have proposed in the scientific literature numerous approaches to the problem, but none of them has led to sucoess. Extensive analysis of the energy-momentum problem in general relativity shows [8, 9, 11–17] that in Einstein's theory there is in principle no solution to this problem, since it does not contain conservation laws for the matter and gravitational field taken together.

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A multifunctional apparatus used for the study and certification of the wavelength of light sources is described. The wavelength range of interest is from O.5– 4.0 pm. The instrument is capable of characterizing the radiation from spectral lamps, as well as gas and semiconductor lasers. An error analysis is presented for the measurement of wavelength using a Fabry-Perot interferometer.