Physicochemical assessment criteria for high-voltage pulse capacitors

In the paper, the applicability of decomposition products of internal insulation of high-voltage pulse capacitors is considered (aging is the reason for decomposition products of internal insulation). Decomposition products of internal insulation of high-voltage pulse capacitors can be used to evaluate their quality when in operation and in service. There have been three generations of markers of aging of insulation as in the case with power transformers. The area of applicability of markers of aging of insulation for power transformers has been studied and the area can be extended to high-voltage pulse capacitors. The research reveals that there is a correlation between the components and quantities of markers of aging of the first generation (gaseous decomposition products of insulation) dissolved in insulating liquid and the remaining life of high-voltage pulse capacitors. The application of markers of aging to evaluate the remaining service life of high-voltage pulse capacitor is a promising direction of research, because the design of high-voltage pulse capacitors keeps stability of markers of aging of insulation in high-voltage pulse capacitors. It is necessary to continue gathering statistical data concerning development of markers of aging of the first generation. One should also carry out research aimed at estimation of the remaining life of capacitors using markers of the second and the third generation.     

Light scattering by molecular-organized films on the surface of polycrystalline gold

Specific features of the structure of self-assembled layers of dodecanthiol on the surface of polycrystalline films of gold are investigated with the aim of revealing the effect of the substrate relief on the lateral distribution and the predominant orientation of thiol molecules within the limits of the layer. The analysis of the angular dependence of quasi-elastically scattered light that takes into account the contributions of the geometric roughness of the surface and the inhomogeneity of the dielectric constant to scattering allowed us to establish the correlation in antiphase between the distribution of the thickness of the thiol coating and the height of the relief of the gold surface. The formation of a thiol layer on the surface of polycrystalline gold is a complex process including adsorption, local self-assembly, and a surface-induced distortion of the ordered structure in the regions of minima of the surface relief. The approach proposed here and based on the nondestructive analysis of thin organized coatings can be efficiently applied for the study of specific features of the topography and the prediction of chemical functionality of self-assembled molecular ensembles.     

Effects of the mixture of one-and three-dimensional inhomogeneities on the wave spectrum of superlattices

Dependences of the dispersion laws and damping of waves in an initially sinusoidal superlattice on the dimensionality of inhomogeneities modulating the period of the superlattice are studied. The cases of one-and three-dimensional modulations, as well as modulation by a mixture of inhomogeneities of both of these dimensionalities, are considered. The correlation function of the superlattice K(r) has the form of a product of the same periodic function and a decreasing function that is significantly different for these different cases. The decreasing part of the correlation function for the mixture of inhomogeneities of different dimensionalities has the form of a product of the decreasing parts of the correlation functions of the components of the mixture. This leads to the nonadditivity of the contributions of the components of different dimensionalities to the resulting modification of the parameters of the wave spectrum that are due to the inhomogeneities (the damping of waves for the mixture of these components is smaller than the sum of the dampings of the components, the maximum gap in the spectrum corresponds to the simultaneous presence of both components of the mixture, not only of the three-dimensional inhomogeneities).     

Modeling of the population dynamics of the states of a three-level molecule in the field of a monochromatic light wave

The formalism and the results of modeling the population dynamics of the states of a three-level model molecule by using the optical Bloch equations are compared with the formalism and results of modeling the population dynamics of the states of the molecule–radiation field system by means of quantum electrodynamics. Examples of significant differences between the results of application of these approaches regarding the behavior of the time dependences of the populations of the states of the molecule, the values of the quantum yield of the photoreaction or the intensity of Rayleigh and resonance Raman scattering are given. These differences are the greater, the higher the rate of the radiative decay of the resonantly excited state with the transition of the molecule to the ground state as compared to the rate of the decay of this state with the transition of the molecule to the third molecule (undecaying) state.     

Bifurcations accompanying monotonic instability of an equilibrium of a cosymmetric dynamical system

It is well known that equilibrium in a cosymmetric system in the general position is a member of a one-parameter family. In the present paper the Lyapunov-Schmidt method and the method of the central manifold are used to analyze bifurcations of such a family of equilibria as well as internal bifurcations: transitions of the type focus-node, node-saddle, and so on during motion along the family. A series of scenarios of branching of families of equilibria and the change in the structure of their arcs, consisting of equilibria of the same type, is described. Bifurcations of stable and unstable arcs, coalescence and decomposition of families of equilibria, bifurcation of the loss of smoothness by the family of equilibria, and branching of a small equilibrium cycle from a corner point of the family of equilibria are investigated in detail. The variability of the spectrum along a family gives rise to a variety of new phenomena that are not encountered in the classical case of an isolated equilibrium or in bifurcations of families of equilibria of a system with symmetry. They include protraction with respect to the branching parameter of the family of equilibria, Lyapunov instability of a family of equilibria with the attraction properties being preserved, and the appearance and disappearance of new stable and unstable arcs on the family of equilibria. (c) 2000 American Institute of Physics.     

Complex degree of mutual anisotropy of linear birefringence and optical activity of biological tissues in diagnostics of prostate cancer

We present theoretical fundamentals of polarization and correlation analysis of the optical anisotropy of biological tissues. Results of measurements of coordinate distributions of the complex degree of mutual anisotropy (CDMA) that are formed by birefringent structures of the prostate tissue with benign and malignant changes are compared. Magnitudes and ranges of variation of statistical (the firstto fourth-order distribution moments) and correlation (excess of autocorrelation functions) parameters of the coordinate CDMA distributions of histological sections of the prostate postoperative bioptic material are studied. Objective criteria of the diagnostics of the appearance of pathology and of the differentiation of the degree of its severity are determined.     

Mathematical modeling of the dynamics of photoreactions of a five-level molecule

A mathematical modeling of the time evolution of the populations of the states of a five-level molecule during transformation of resonant monochromatic irradiation and spontaneous emission from the highest-energy state excited by a short pulse of light is performed. The formalism of the optical Bloch equations and quantum theory of radiation are applied a composite system consisting of a molecule and a quantized radiation field. The results of simulation of the evolution of the population of the states of the molecule in the case of spontaneous emission are similar for both of these two approaches, but differ significantly in the case of conversion by the molecule of monochromatic radiation. These differences are the greater, the higher the intensity of resonance Rayleigh scattering or (and) relaxed fluorescence, as a result of which the molecule returns to the initial ground state. An explanation of the nature of these differences is given.     

The use of stability bands to improve the performance of quadrupole mass filters

The possibility of increasing the resolving power of quadrupole mass filters has been discussed. It has been shown that the limitations associated with the finite time of flight imposed by Von Zahn’s rule are modified while using the islands of stability that appear when quadrupole is excited by the additional signals. By calculation of the exponential increment of growth of the oscillation amplitude the effect of the acceleration of mass separation and improvement of the peak shape, when the islands of stability are used for ion filtering, is explained. The case of the excitation by two signals at different frequencies has been studied theoretically. The conditions under which suppression of the first order resonance for one of the directions of motion is obtained. The direct modeling of the peak shape of the mass filter shows the possibility of obtaining a resolution of 10,000 with a time of flight of ions through the quadrupole of 100 cycles of the main RF supply, and low sensitivity of the new operating mode to the nonlinear field distortions in the quadrupoles with rods of circular cross sections.     

Nonlinear polariton waves in an optical double lattice with photo-induced transport of atoms

The process of photo-induced transport of cold atoms in optical lattices is discussed for the case in which the direct tunneling of atoms is suppressed but transport of an atom is possible as a result of simultaneous absorption and reemission of two photons with different energies. Proceeding from the Bose-Hubbard model for two kinds of traps of a one-dimensional optical lattice, a set of equations describing the propagation of an ultrashort pulse of biharmonic radiation accompanied by a transfer of populations of traps of such a double lattice is derived. It was found that, depending on the choice of boundary conditions, there exist two types of stationary solitary waves corresponding to the propagation of a coupled pair of soliton pulses: a pair of bright solitons and a coupled pair of dark and bright solitons.     

Characteristic features of electronic and vibrational spectra of free polyatomic molecules

The functional relationships between the basic characteristics of individual bands of electronic and vibrational spectra of free polyatomic molecules are ascertained. These basic characteristics are the position of the maximum of an individual electronic-vibrational band, the rate of the temperature shift of the maximum of a band, the half-width of a homogeneously or heterogeneously broadened electronic-vibrational band, the rate of the temperature variation of the half-width of a band, the asymmetry parameter of a heterogeneously broadened band, and the conditions for symmetric or asymmetric distribution of the intensity over the contour of a spectral band. The interrelations between the basic spectral characteristics result from the sequential mechanism of formation and broadening of individual bands of electronic and vibrational spectra of free polyatomic molecules. It is shown that the investigation of the basic spectral characteristics of electronic-vibrational bands and their interrelations allows one to elucidate the nature of the internal motion determining the optical properties of polyatomic molecules.     

Theory of measurement of entangled states

Problem on reconstruction of state of finite-dimension quantum information transfer channel, pure or mixed, by results of measurements of needed number of observables, is considered. It is shown that in general case it is needed to measure incompatible observables in number exceeding by one dimension of space of vectors of state. Each of incompatible observables is measured in its statistically valuable series of measurements. In special case, when one of observables is a non-demolition observable, measurement of the other observables is needed for realization of control of property of non-demolition. In case of paired channel it is shown that results of measurements of observables that do not demolish states of sub-channels are characterized by mutual distribution of probabilities while results of measurement of over-classical observables are characterized by mutual correlation only. This correlation vanishes completely in case of pure unentangled states.     

Effect of absorption of multiply scattering media on the degree of residual polarization of backscattered light

The effect of absorption in a scattering medium on the degree of residual polarization of backscattered radiation is studied in the case of probing of multiply scattering media by a linearly polarized light. An approximate expression describing the dependence of the degree of residual linear polarization of the backscattered radiation on the optical characteristics of a multiply scattering medium is derived within the framework of the phenomenological approach, based on the concept of the distribution of the optical paths of partial components of the scattered optical field under the conditions of multiple scattering, and with the use of the ideas about the similarity of statistical moments of the multiply scattered optical fields. The cut-off of the partial components, characterized by a large value of the optical path, because of their absorption, results in a substantial increase of the degree of residual polarization for the bands of the selective absorption caused by the presence of chromophores in the scattering medium. The results of experiments with model scattering media (whole milk) and biological tissues (human skin in vivo) are presented.     

Fluctuations in the number of photons above the bifurcation point in the process of third harmonic generation

The quantum fluctuation of the number of photons of the fundamental mode and of the third harmonic in the process of intracavity generation of the third harmonic in the region of unstable behavior of the system is studied. The distribution functions of the number of photons of interacting modes, as well as the function of the joint distribution of the number of photons of the fundamental mode and of the third harmonic, are calculated in the positive P-representation.     

Generalization of the variational principle and the Hohenberg and Kohn theorems for excited states of Fermion systems

Through the entanglement of a collection of K non-interacting replicas of a system of N interacting Fermions, and making use of the properties of reduced density matrices the variational principle and the theorems of Hohenberg and Kohn are generalized to excited states. The generalization of the variational principle makes use of the natural orbitals of an N-particle density matrix describing the state of lowest energy of the entangled state. The extension of the theorems of Hohenberg and Kohn is based on the ground-state formulation of density functional theory but with a new interpretation of the concept of a ground state: It is the state of lowest energy of a system of KN Fermions that is described in terms of the excited states of the N-particle interacting system. This straightforward implementation of the line of reasoning of ground-state density functional theory to a new domain leads to a unique and logically valid extension of the theory to excited states that allows the systematic treatment of all states in the spectrum of the Hamiltonian of an interacting system.     

The main periodicities of the motion of the center of the sun relative to the center of mass of the solar system and solar activity

The dynamic parameters of the motion of the Sun relative to the center of mass of the Solar System, viz., the distance of the center of the Sun relative to the center of mass and the angular momentum of the Sun, as well as its changes, are investigated. The frequency spectra of these parameters and of the Wolf numbers are calculated and the main spectral components are revealed. It is shown that a periodicity of 178.8 years is not predominant in the dynamic parameters of the motion of the Sun; in this frequency range a periodicity of 169 years connected with the influence of Neptune predominates. The coincidence of the periodicities in the Wolf numbers and dynamic parameters of the motion of the Sun is shown. The causes of all components of the frequency spectrum are indicated.     

Scattering of centimeter radiowaves in a gas ionized by radioactive radiation: Cluster plasma formation

A theoretical explanation is proposed for an anomalously high reflectivity of air masses exposed to radioactive radiation relative to electromagnetic waves from the rf range. The mechanism of formation of the reflected signal is connected with a change in the electric parameters of the ionized gas. The concentration of free charges under the typical conditions of radioactive contamination is ten orders of magnitude lower than that required for the formation of an experimentally detectable reflected signal. The discrepancy between the values of reflectivity observed under the real conditions of radar probing and predicted theoretically on the basis of the elementary theory of a weakly ionized gas amounts to 20 orders of magnitude. It is shown that the inclusion of the variation of the mass and the critical capture radius of ions due to their hydration changes the difference between the theoretical predictions and the experimental observations insignificantly. The discrepancy becomes smaller (but only by 1.5 orders of magnitude) when the scattering of radiowaves from turbulent vortices is taken into account. The mechanism of the formation of the high reflectivity is associated with slowing down the recombination and with the accumulation of a profuse population of unrecombined ionic pairs stabilized in the clusters of water molecules. The steady-state concentration of such electrically neutral clusters is several orders of magnitude higher than the concentration of free hydrated ions. A variation of the intensity of ionizing radiation is accompanied by proportional variations of both components. The recombination barrier is formed as a result of drawing dipole molecules into the gap between ions at the final stage of motion of counterions towards one another before their recombination. The accumulation of ionic pairs ensures the multiple enhancement of the sensitivity of the electric properties of cold plasma to the effect of ionizing radiation. A quantitative kinetic theory of the effect is constructed. The numerical calculations of the parameters of the pre-recombination states of ions against the background of the molecular component are made using computer simulation at the microscopic level. The steady-state recombination rate is an exponential function of the pre-recombination barrier height and decreases rapidly even upon an insignificant change in the number of molecules involved in an ion recombination act. The obtained theoretical conclusions are confirmed by the independent results of observations of the strong absorption band in the atmosphere in the middle part of the IR spectrum, which is attributed to the anomalously high concentration of electrically neutral water clusters.     

Polarization contrast enhancement of images of biological tissues under the conditions of multiple scattering

The concept of laser polarization probing of biological tissues under the conditions of scattering of high multiplicities is analyzed and approbated experimentally. The effect of the degree of depolarization of the scattered background on the signal-to-noise ratio in coherent images of an optically anisotropic architectonic of the morphological structure of a biological tissue and of the polarization correction of the probing beam on the contrast enhancement of these images are considered.     

UV-B诱导的大豆愈伤组织异黄酮和超弱发光的变化

利用基于单光子技术的超弱发光测量系统研究了UV-B辐射对大豆愈伤组织异黄酮和超弱发光的影响,UV-B辐射的强度范围为20～80 μW/cm2.结果表明,UV-B辐射使大豆愈伤组织延迟发光初始强度和自发发光强度明显增强,随着诱导处理后时间的延长,延迟发光初始强度和自发发光强度逐渐减小,大豆异黄酮含量逐渐增加,大豆异黄酮含量的变化与延迟发光初始发光强度的变化之间呈现负相关.结果表明,UV-B辐射使大豆愈伤组织总体代谢和活性氧代谢强度提高,大豆异黄酮含量提高是自发发光和延迟发光强度降低的原因,大豆异黄酮含量的增加可以用延迟发光初始发光强度的降低来量度.