Determination of the Disperse Composition of a PbO Suspension Containing Aggregates of Particles of Lamellar Shape by the Laser-Polarimetry Method

The results of measurements of the scattering matrix at a wavelength of 0.63 μm in the range of scattering angles of 10°–155° are presented for an aqueous suspension of lead oxide containing particles of plate form and their aggregates of monomers with dimensions of ~5 nm. The results of the measurements are compared with the results of calculations for axially symmetric scatterers (ellipsoids of rotation, cylinders). It is shown that the presence of aggregates affects the scattering properties of such a medium. The results of reconstructing the distribution of particles of a disperse medium in sizes from the measurements data of the scattering matrix are presented. The reconstruction of the distributions was carried out by solving the problem of optimizing the sum of the squared deviations of the experimental and calculated values of matrix elements in the framework of the model of axially symmetric scatterers. It is shown that the distribution of particles by sizes is more accurately reconstructed by minimizing the sum of the squares of the deviations for the sum of the diagonal elements. The obtained distribution is compared with the distribution measured by the method of dynamic light scattering.     

Complex polarization-phase and spatial-frequency selections of laser images of blood-plasma films in diagnostics of changes in their polycrystalline structure

We present a theoretical formalism of correlation phase analysis of laser images of human blood plasma with spatial-frequency selection of manifestations of mechanisms of linear and circular birefringence of albumin and globulin polycrystalline networks. Comparative results of the measurement of coordinate distributions of the correlation parameter—the modulus of the degree of local correlation of amplitudes—of laser images of blood plasma taken from patients of three groups—healthy patients (donors), rheumatoid-arthritis patients, and breast-cancer patients—are presented. We investigate values and ranges of change of statistical (the first to fourth statistical moments), correlation (excess of autocorrelation functions), and fractal (slopes of approximating curves and dispersion of extrema of logarithmic dependences of power spectra) parameters of coordinate distributions of the degree of local correlation of amplitudes. Objective criteria for diagnostics of occurrence and differentiation of inflammatory and oncological states are determined.     

2D-Mueller-matrix tomography of optically anisotropic polycrystalline networks of biological tissues histological sections

A new technique of Mueller-matrix mapping of the birefringent structure of biological preparations of human organs tissues is suggested. The algorithms of reconstruction of average values and magnitude of fluctuations of the phase (birefringence) and amplitude (dichroism) of optically anisotropic structure of myocardium and connective tissue component of the vaginal wall histological section are proposed. The magnitudes and ranges of changes in the statistical moments of the 1st-4th order that characterize the distribution of average values and magnitude of fluctuations of birefringence and dichroism of the myocardium and connective tissue of the vaginal tissues histological sections were determined. Joint studies of distributions of the characteristics of phase and amplitude of the anisotropy of myocardium and connective tissue component of the vaginal wall tissues of different states were performed. The cases of various necrotic changes in the myocardium and pathological conditions of the vagina wall (prolapse of the genitals) are examined. Balanced accuracy of the method of Mueller-matrix polarization-phase and diffuse tomography of optically anisotropic polycrystalline networks in the differentiation of necrotic and pathological changes in human organs is determined.     

Application of the neural network method for determining the characteristics of homogeneous spherical particles

The problem of reconstructing the characteristics of disperse particles from measurements of scattered radiation is considered. To solve this problem, the neural network method, based on the approximation of the parameters of particles by a linear combination of the results of measurements, is used. The capabilities of the method are studied on the examples of the reconstruction of the radius and the refractive index of spherical particles from measurements (for example, in flow-type cytometers) of the luminance of radiation scattered by individual particles, as well as the reconstruction of the mean radius, the coefficient of variation, and the refractive index from measurements of the luminance of radiation scattered by an ensemble of particles. Errors in the reconstruction of the characteristics of disperse particles depending on the structure of the neural network and the parameters of particles are studied.     

Modeling of the vibrational structure of the vibronic spectra of diphenylpolyenes by the parametric method

The structures of the electronic-vibrational spectra and of the excited states of a number of diphenylpolyene molecules are determined within the framework of the second approximation of the parametric method. The system of parameters of the structural fragments of molecules is improved and good agreement with spectral experiment is obtained. It is shown that there is a high degree of transferability of the polyene and acene parameters of the method and that the models obtained are adequate to the real structure of molecules. It is also shown that the method proposed makes it possible to perform predictive qualitative and quantitative calculations of the spectra of these molecules, as well as of the spectral characteristics necessary for modeling photochemical molecular transformations. In the series of diphenylpolyene molecules, an interpretation of the vibrational structure of the spectra is proposed and the specific features of variation of the geometry upon excitation of molecules are considered.     

The concept of the use of recycled uranium for increasing the degree of security of export deliveries of fuel for light-water reactors

The present paper deals with investigation of the possibilities for reducing the risk of proliferation of fissionable materials by means of increasing the degree of protection of fresh fuel intended for light-water reactors against unsanctioned use in the case of withdrawal of a recipient country of deliveries from IAEA safeguards. It is shown that the use of recycled uranium for manufacturing export nuclear fuel makes transfer of nuclear material removed from the fuel assemblies for weapons purposes difficult because of the presence of isotope ²³²U, whose content increases when one attempts to enrich uranium extracted from fresh fuel. In combination with restricted access to technologies for isotope separation by means of establishing international centers for uranium enrichment, this technical measure can significantly reduce the risk of proliferation associated with export deliveries of fuel made of low-enriched uranium. The assessment of a maximum level of contamination of nuclear material being transferred by isotope ²³²U for the given isotope composition of the initial fuel is obtained. The concept of further investigations of the degree of security of export deliveries of fuel assemblies with recycled uranium intended for light-water reactors is suggested.     

Nanostructures with Ge–Si quantum dots for infrared photodetectors

In this paper questions of optimization of growth conditions in the method of molecular beam epitaxy for creation of high-efficient quantum dot infrared photodetectors are considered. As a model material system for theoretical investigations, heterostructures with germanium-silicon quantum dots on the silicon surface are chosen. For calculations of the dependencies of quantum dots array parameters on synthesis conditions the kinetic model of growth of differently shaped quantum dots based on the general nucleation theory is proposed. The theory is improved by taking into account the change in free energy of nucleation of an island due to the formation of additional edges of islands and due to the dependence of surface energies of facets of quantum dots on the thickness of a 2D wetting layer during the Stranski–Krastanow growth. Calculations of noise and signal characteristics of infrared photodetectors based on heterostructures with quantum dots of germanium on silicon are done. Dark current in such structures caused by thermal emission and barrier tunneling of carriers, as well as detectivity of the photodetector in the approximation of limitation by generation-recombination noises are estimated. Moreover, the presence of dispersion of quantum dots by size is taken into account in the calculations of the generation-recombination noises. Results of calculations of the properties of structures with quantum dots and their dependencies on growth parameters, as well as the characteristics of quantum dot photodetectors are presented. Comparison of the estimated parameters of quantum dots ensembles and the characteristics of quantum dot photodetectors with experimental data is carried out.     

Theoretical study of the effect of temperature differential and ionizing radiation on the current–voltage characteristics of HEM transistors

Requirements to the modeling of the effects of temperature differential and ionizing radiation on the current–voltage characteristics of high electron mobility transistors (HEMTs) were formulated. The results of modeling of the effects of temperature differential on the current–voltage characteristics of HEMTs were described. The results of analysis of the effects of ionizing radiation on the current–voltage characteristics of HEMTs were given. The results of modeling of the effects of ionizing radiation on the current–voltage characteristics of HEMTs were presented.     

Specific features of determination of the energy of excited electronic states in the formalism of density functional theory

Possibilities for application of the theory of subspaces to determination of the energy of excited electronic states are studied in terms of density functional formalism. Specific features of computer implementation of the theory in a basis of spherical Gaussian functions, whose parameters are determined by minimizing the energy of the corresponding subspace of states, are discussed. The results of calculation of the energy of excited states and the excitation energies of simple atoms and molecules are presented to demonstrate the potential of the approach.     

A sufficient condition of applicability of the model of a chemical equilibrium mixture to describing the state of detonation products

A sufficient condition of applicability of the model of a chemical equilibrium mixture to gasdynamic calculations based on a comparison of the rate of change of the equilibrium concentrations of the products in gas-dynamic process with the rate of chemical reactions leading to the establishment of chemical equilibrium is obtained. An example of using this condition in examining the applicability of the model of a chemical equilibrium mixture to the products of detonation of spherical charges of oxyacetylene and hydrogen-air mixtures the in the air is presented.     

Discrete gravity,the problem of fermion state doubling,and quantum anomalies

The problem of doubling of fermion states is studied in the framework of the theory of discrete gravitation. Examples of amorphous lattices (simplicial two-, three-, and four-dimensional complexes) free of doubling of fermion states are given. Possible consequences of this fact, such as the absence of quantum anomalies in divergence of axial currents, are considered. On the basis of the absence of axial anomalies and the finiteness of the number of physical degrees of freedom in the model of discrete quantum gravity proposed in [1] and of the continuum theory of gravitation constructed with the help of the dynamic quantization method [2], the following conclusion has been drawn: discrete quantum gravity [1] in the continuum limit is transformed into the theory of gravitation constructed in accordance with the algorithm of the dynamic quantization method [2].     

Visualization of scattering media upon backscattering of a linearly polarized nonmonochromatic light

The method of polarization visualization of multiply scattering macroinhomogeneous media, based on analysis of the spatial distributions of polarization characteristics of a linearly polarized radiation backscattered from a medium, is discussed. The effect of optical characteristics of the medium and the scattering geometry on the quality of the images obtained in the case of visualization of an absorbing heterogeneity immersed into a multiply scattering medium is considered. The comparative analysis of the quality of formed images was performed with the use of different polarization characteristics of the backscattered radiation as a visualization parameter. The theoretical interpretation of the obtained experimental results is given within the framework of the phenomenological approach based on the concept of the distribution of the effective optical paths of partial components of the scattered optical field. To calculate the probability density of the effective optical paths, the statistical simulation method was used.     

Reconstruction of synthesized holograms-Fresnel projectors at angles of incidence of reconstructing wave that exceed the angle of incidence of the reference wave in hologram synthesis

The possibility of the aberration-free reconstruction of a synthesized hologram-Fresnel projector in the case when the angles of incidence of the reconstructing plane wave exceed the angle of incidence of the plane reference wave during hologram synthesis is shown. The character of the dependence of admissible angles of incidence of the reconstructing wave on the parameters of the synthesis of hologram projectors is revealed and described mathematically. The results of an experimental study that confirms the possibility of the aberration-free reconstruction of hologram projectors at angles of incidence of the reconstructing plane wave that exceed the angle of incidence of the reference wave of the plane are presented. The results of the successful implementation of the projection photolithography process using a synthesized relief-phase reflection hologram-Fresnel projector are demonstrated.     

Reconstruction of the form of complex motion of an object from the autodyne detection signal of a semiconductor laser

The possibility of reconstructing the shape of an interference signal on the basis of the autodyne detection signal of a semiconductor laser is demonstrated in cases of harmonic and nonharmonic vibrations of the object of study. The shape of the interference signal coincides with the shape of the signal of an interference system decoupled from the radiation source. It is shown that the form of nonharmonic vibrations can be reconstructed from the values of the autodyne signal function at four varying distances from the external vibrating reflector. Numerical simulation of the procedure of reconstruction of the shape of the interference signal was performed. The main limitations of the method under consideration are discussed.     

时间、空间与运动——狭义相对论及其伟大科学意义

介绍狭义相对论诞生的历史背景,爱因斯坦创立狭义相对论的新思维和创造性,发现自然界两条基本原理及其建立新的相对性时空结构理论及新的运动学定律的思路历程.由此揭示和证明时空相对性结构是一切自然界定律对相对运动保持其不变性和对称性的基础,也是自然界因果关系成立的基础,最后介绍从狭义相对论得出的自然界的一系列新奇结论和定律.     

Reconstruction of the characteristics of a light-scattering layer from its reflectance and transmittance: The neural network method

The problem of reconstructing the probability of photon survival, the optical layer thickness, and the parameter of asymmetry of the scattering indicatrix of an elementary volume from the dependence of the reflectance and the transmittance on the angle of incidence of radiation onto a layer of a medium with Fresnel reflection from the boundaries is considered. To solve this problem, a method based on the use of correlation neural networks is proposed. For training and control of the operation of neural networks, the reflectance and the transmittance of the layer calculated within the framework of the radiation transfer theory were used. For the simulation of the scattering characteristics of an elementary volume, the Mie theory was used. Estimates of errors in the reconstruction of the characteristics of the medium were performed.     

Formation of associates of solvated cations in salt solutions in polar dielectric liquids

Experimental results are presented on excitation of oscillations of polarization charges of solvated ions in an aqueous solution of a mixture of cerium and lead nitrates under an external asymmetric electric field and the directed motion of solvated cerium and lead cations, caused by this process. The applicability of the approximation of the existence of a self-consistent electric field in the solution volume to explain the observed frequency ranges of the manifestation of the effect of electroinduced selective drift of solvated cations is demonstrated. The results of a theoretical analysis of the possibility of forming associates from solvated ions are presented.     

Absorption of electromagnetic radiation by a bimetallic cylindrical particle of finite length

The absorption cross section of electromagnetic radiation is calculated for a bimetallic cylindrical particle of finite length. A general case is considered, where the ratio of the radius of the particle core to the particle radius and the ratio of the radius of the particle to its length can take arbitrary values. The conditions of diffuse reflection of electrons from the internal and external surfaces of the metal shell of the particle and from its faces are used as the boundary conditions of the problem. The effect of the ratio of the radius of the core of a bimetallic cylindrical particle to the particle radius and the ratio of the radius of the particle to its length on the electromagnetic properties of the particle is analyzed.     

Effect of spatial nonuniformity of heating on compression and burning of a thermonuclear target under direct multibeam irradiation by a megajoule laser pulse

Direct-drive fusion targets are considered at present as an alternative to targets of indirect compression at a laser energy level of about 2 MJ. In this approach, the symmetry of compression and ignition of thermonuclear fuel play the major role. We report on the results of theoretical investigation of compression and burning of spherical direct-drive targets in the conditions of spatial nonuniformity of heating associated with a shift of the target from the beam center of focusing and possible laser radiation energy disbalance in the beams. The investigation involves numerous calculations based on a complex of 1D and 2D codes RAPID, SEND (for determining the target illumination and the dynamics of absorption), DIANA, and NUT (1D and multidimensional hydrodynamics of compression and burning of targets). The target under investigation had the form of a two-layer shell (ablator made of inertial material CH and DT ice) filled with DT gas. We have determined the range of admissible variation of compression and combustion parameters of the target depending on the variation of the spatial nonuniformity of its heating by a multibeam laser system. It has been shown that low-mode (long-wavelength) perturbations deteriorate the characteristics of the central region due to less effective conversion of the kinetic energy of the target shell into the internal energy of the center. Local initiation of burning is also observed in off-center regions of the target in the case of substantial asymmetry of irradiation. In this case, burning is not spread over the entire volume of the DT fuel as a rule, which considerably reduces the thermonuclear yield as compared to that in the case of spherical symmetry and central ignition.     

Wavelet analysis of the polarization structure of biospeckle fields of statistical and multifractal phase-inhomogeneous layers

The mechanisms of formation of the polarization structure of biospeckle fields of statistical and multifractal phase-inhomogeneous layers are studied. Polarization maps of images are determined for biological tissues of various structures, namely, epidermis, muscular tissue, and myometrium. A relation between the polarization structure of biospeckles and the physiological conditions of phase-inhomogeneous layers is found. The distributions of wavelet coefficients of the polarization images of statistical and multifractal biological tissues are obtained. Criteria for the determination of the coordinate localization and scale of optical inhomogeneities of the architectonics of biological tissues are ascertained.