Finding Solutions to Equations for the Longitudinal Components of an Electromagnetic Field in a Biisotropic Medium in the Neighborhood of a Regular Singular Point as Generalized Power Series

For a system of equations that describe electromagnetic fields in a biisotropic medium, particular solutions have been constructed in the neighborhood of a regular singular point. The solutions are written in the form of generalized power series. For the coefficients of the power series, exponents and recursion relations have been found. It has been shown that the solutions of the wave equations are generalizations of well-known special cylindrical functions. The behavior of the particular solutions have been examined for varied material parameters of the medium. The solutions obtained allow one to formulate mathematical models which could be used to calculate and optimize the parameters of a wide spectrum of functional devices based on waveguide structures with biisotropic inserts.     

Isotropic Maxwell-Garnett model for biisotropic-in-biisotropic mixtures

The Rayleigh scattering response of an electrically small biisotropic sphere immersed in an ambient biisotropic medium has been utilized in constructing a Maxwell-Garnett model of a composite material formed by randomly dispersing biisotropic spheres in a biisotropic host medium. It is anticipated that this work will be of interest for estimating the electromagnetic properties of particulate media.     

Excitation of coupled TM-TE focus wave modes in biisotropic media

We prove that two kinds of coupled TM-TE focus wave modes can propagate in a biisotropic medium, and we consider what happens when a TM or TE focus wave mode impinges from a vacuum on a slab made of a biisotropic material. We get the amplitudes of the reflected and refracted waves in a chiral slab.     

On the scattering of an obliquely incident plane wave by a biisotropic cylinder

Scattering of an obliquely incident electromagnetic plane wave by an infinitely long, homogeneous, biisotropic cylinder is addressed. The ambient host medium considered is isotropic, homogeneous and dielectric-magnetic. It is observed that the constitutive coupling of the electric and the magnetic fields in the biisotropic material causes the cross-polarization component of the scattered field not to vanish even for the normal incidence case.     

Transverse coupling between two general biisotropic slabs

The general formulation for the determining of transverse coupling behaviour between two different biisotropic slabs is proposed based on the method of conventional field perturbation, and some special cases are considered. Since biisotropic medium is a generalization of the well-studied nonreciprocal and reciprocal chiral media, our results are suitable for much more cases.     

Characteristic electromagnetic waves in a circular waveguide filled with a biisotropic medium

A numerical solution is given for the problem of characteristic electromagnetic waves in a circular waveguide with a biisotropic rod. The dependences of the propagation constants of the different wave modes on the chirality parameter, nonreciprocity, and permittivity of the rod are obtained. The results presented can be useful when developing devices and measuring the parameters of biisotropic materials. State University, Tomsk. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 48–52, February, 1997.     

Radiation patterns of electric dipole antenna in the presence of a biisotropic sphere

Analytic expressions of the dyadic Green's function of an arbitrary electric current source embedded in a general biisotropic sphere are presented at first, and the radiation characteristics of an electric dipole antenna placed on the surface of a biisotropic sphere lens are examined. The effects of the electric-and the magnetic-coefficients ( _e and _m ) of biisotropic medium on the radiation patterns of electric dipole antenna are investigated in detail.     

Natural Electromagnetic Waves in a Circular Waveguide with a Chiral and a Dielectric Layer

Based on particular solutions of a system of wave equations which describe electromagnetic processes in an unbounded biisotropic medium and are represented in the form of generalized power series, a dispersion equation is obtained for a two-layer circular waveguide with a chiral and a dielectric layer. The solution of the dispersion equation is analyzed for some types of natural waves.     

Field of a Point Source Within Perfectly Conducting Parallel-Plates in a Homogeneous Biisotropic Medium

The spherical wave scattering response by a perfectly conducting open–ended waveguide in a biisotropic medium is obtained. Interestingly, the vector diffraction problem is reduced to the scattering of a single scalar field, this scalar field being the normal component of either a left–handed or a right–handed Beltrami field. Here, we explicitly consider the scattering of the left–handed field component, that of the other scalar field being analogously tractable. The solution is constructed with the aid of the Wiener–Hopf technique.     

Spectral dyadic Green's function formulation for uniaxial bianisotropic superstrate-substrate structure

In this paper, spectral-domain dyadic Green's functions for the time harmonic electric current source embedded in a two-layer grounded uniaxial bianisotropic media are obtained using Fourier tranform. It is shown that in the uniaxial bianisotropic medium, total spectral electromagnetic field can also be separated into the superposition of transverse electric (TE) and transverse magnetic (TM) wave. Because of the generality of constitutive relations our results include the special cases of achiral, uniaxial, reciprocal and nonreciprocal biisotropic media.     

Scattering of Plane Electromagnetic Waves from a Biisotropic Sphere in Vacuum

The boundary-value problem on scattering of a plane circularly polarized electromagnetic wave from a biisotropic sphere in vacuum has been solved. The coefficients for scattered and internal fields have been obtained and numerically analyzed.     

On the dyadic Green's functions for Beltrami fields

A simple derivation of the Green's functions for Beltrami fields is presented for use with time-harmonic electromagnetism in homogeneous biisotropic media.     

Analysis of Spectral Hounsfield Units Curve of Radiolucent and Radiopaque Materials in the Animal Rectum

The purpose of the present study was to assess the general characteristics of images produced by radiolucent and radiopaque materials used for computed tomography scanning of the animal rectum and suggest ideal materials for contrast enhancement between normal and abnormal tissues. The computed tomography system used in this study was 64-multidetector computed tomography. Computed tomography scanning was performed with standard scan parameters for abdominal examination and gemstone spectral image mode using saline, methyl-cellulose, contrast medium, ultrasound gel, and air in addition to radiolucency. Computed tomography values were obtained for each material at different energy levels. Changes in computed tomography values were compared and analyzed. Changes in computed tomography values and volume of each material were examined before and after rectal contrast material administration. Ultrasound gel was found to exhibit a computed tomography value close to the baseline value and a greater degree of contrast, compared with other materials. In image evaluation, methyl-cellulose is considered a useful material in providing contrasting image evidence of rectal diseases. Also, it had a larger volume in the rectum after a computed tomography scan. Thus, methyl-cellulose was a useful contrast medium for computed tomography scan imaging of the rectum.     

Reciprocity and the concept of the brewster wavenumber

Reflection of planewaves at the planar interface of two biisotropic media has been examined in order to obtain the Brewster wavenumber. This examination shows that the Brewster wavenumber is, at least, not necessarily affected by the reciprocity or the non-reciprocity of the media on either side of the planarinterface.     

Scattering of electromagnetic waves by a bi-isotropic sphere

The scattering of a plane electromagnetic wave at a bi-isotropic sphere is studied, and exact analytical representations are obtained for the fields inside and outside the sphere. Expressions corresponding to Rayleigh scattering can be used to find the effective values of the material parameters of a heterogeneous composite medium consisting of small bi-isotropic spheres randomly disseminated throughout a homogeneous dielectric.V. D. Kuznetsov Siberian Institute of Physics and Technology, Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 108–112, October, 1994.     

模拟钻地弹的设计与实验研究

 对钻地弹的弹体材料、弹体参数、气动性能、侵彻过载和侵彻深度等问题进行了研究。在此基础上，设计了模拟钻地弹，并进行了外场试验，试验取得了成功，且得到一些有益的结论。     

A study of balancing the competing effects of ultrashort laser induced plasma for optimal laser machining

We report that plasma generated during processing of materials with ultrashort pulse lasers and the associated high intensity optical beam have both favourable and unfavourable impact on the machined surface quality. Intensity of the optical beam propagating through ambient air medium enhanced further by self-focusing is sufficiently high to cause gas breakdown forming air plasma. The generated plasma reduces the effect of self-focusing but also distorts the beam profile. Duration of the pulse being too short for thermal equilibrium to establish, ablation occurs largely by direct removal of the material forming another plasma plume. Normally, the scattering effect of plasma results in distortions of the fabricated features. However, for certain parameter ranges, the competing self-focusing and gas plasma plumes supplemented with the material plasma can combine to cause filamentation, eliminating the distortions. Filament of hot plasma also acts as a well-shaped energy source. In the present study, brass is taken as an example for the investigation. Experiments were conducted to capture the spectrum of the light scattered by plasma using a spectrometer. Analysis was done to estimate the material plasma. Theoretical calculation on the intensity distribution in an optical beam propagating through air was then followed for a range of parameter values taking the self-focusing effect of the medium and the impact of the plasma generated by its breakdown. Approximate values of the machining parameters for clean fabrication are deduced from the calculations, which were used to conduct a laser machining test on brass.     

Effect of transport in a semiconductor thermoelectric generator on its efficiency

The effects of electrical transport and thermal diffusion in the working medium of a thermoelectric generator (TEG) on its efficiency and maximum useful power are examined. Equations are derived to describe these effects, and dimensionless parameters are found whose values are governed by the thermodynamic and kinetic characteristics of the material. Numerical estimates carried out show that it is possible to increase the efficiency and power of a TEG by selecting materials having suitable transport characteristics. The semiconductor alloys of the T1-S system are interesting in this regard.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 8, pp. 63–69, August, 1969.     

Ultrasonic scattering by two concentric cylinders

A series solution for scattering from two concentric, fluid cylinders of different speeds and densities has been employed to compute the scattered pressure for a range of frequencies, material parameters, and emitter and detector functions. This range includes the nominal parameters of measurements that were made at a frequency of 1.0 MHz and a radius of 150 mm on a gel model with an outer radius of 25.00 mm and an inner radius of 9.52 mm. The nominal parameters correspond to a ka of 626.2 for the measurement radius, a ka of 106.0 for the outer cylinder, and a ka of 39.8 for the inner cylinder. Scattering was calculated for frequencies for 10 kHz to 10 MHz which resulted in ka values from 6.26 to 6262 for the measurement radius, from 1.06 to 1060 for the outer cylinder, and from 0.398 to 398 for the inner cylinder. The effects on scattering of changes in speed and density parameters of the concentric cylinders are presented. First, the speed of the outer cylinder was raised by a factor of 10 from the nominal while the density of the outer cylinder and the speeds and densities of the inner cylinder and the surrounding medium were held fixed. Next, the density of the outer cylinder was raised while its speed was fixed at nominal, as were the speeds and densities of the inner cylinder and the medium. Finally, the speed first and then the density of the inner cylinder was raised while the parameters of the outer cylinder and of the medium were held fixed at nominal.(ABSTRACT TRUNCATED AT 250 WORDS)     

Local field and radiative relaxation rate in a dielectric medium

The effect of macroscopic parameters of a substance on the optical characteristics of impurity particles is investigated. A generalized control equation is derived for two-level emitters forming an ensemble of optical centers in a transparent dielectric medium. In this equation, the effective values of the acting pump field and the radiative relaxation rate of an optical center are taken into account. The formalism developed here is a completely microscopic approach based on the chain of the Bogoliubov-Born-Green-Kirkwood-Yvon equations for reduced density matrices and correlation operators for material particles and modes of a quantized radiation field. The method used here makes it possible to take into account the effects of individual and collective behavior of emitters, which are associated with the presence of an intermediate medium, consistently without using phenomenological procedures. It is shown that the resultant analytic expression for the effective lifetime of the excited state of an optical center conforms with experimental data.