Base Drag Reduction and Generation of the Lifting Force Using a Microwave Discharge in a Supersonic Flow

Technical Physics - We report on the results of experimental investigation of forced action of a deeply subcritical microwave discharge initiated in a quasi-optical electromagnetic beam on bodies...     

Mesoscopic photon heat transistor

We show that the heat transport between two bodies, mediated by electromagnetic fluctuations, can be controlled with an intermediate quantum circuit--leading to the device concept of a mesoscopic photon heat transistor (MPHT). Our theoretical analysis is based on a novel Meir-Wingreen-Landauer-type of conductance formula, which gives the photonic heat current through an arbitrary circuit element coupled to two dissipative reservoirs at finite temperatures. As an illustration we present an exact solution for the case when the intermediate circuit can be described as an electromagnetic resonator. We discuss in detail how the MPHT can be implemented experimentally in terms of a flux-controlled SQUID circuit.     

Diffraction and propagation of electromagnetic waves in the presence of chiral media

The propagation of electromagnetic waves in infinite, semiinfinite, and laminar chiral structures is investigated, along with the diffraction of electromagnetic waves on semiinfinite objects in a chiral medium and three-dimensional objects consisting entirely or partially of chiral materials. Particular attention is paid to diffraction on three-dimensional uniform chiral bodies and ideally conducting bodies covered by chiral shells. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 50–61, August, 1998.     

Wave Flow and the Resonant Decrease in the Radiation Visibility of Extensive Corrugated Diffusers

In this paper, the problem of electromagnetic wave diffraction by extensive conducting bodies with uniform cross sections and continuous curvature boundaries is studied. Corrugated cylinders are considered as diffusers. A resonant decrease in the radiation visibility of such bodies was discovered.     

Gravity induced magnetic instability

In the presence of a gravitational field the stability of a magnetoplasma is studied against electromagnetic perturbations. We have shown that a pinching type of instability can be triggered with a sizable growth rate affecting the equilibrium configuration of the confining magnetic field. This might have a profound effect on the magnetic fields of astrophysical bodies.     

Non-inertial electromagnetic effects in matter. Gyromagnetic effect

Non-inertial electromagnetic effects in matter, i.e. electromagnetic fields created by a non-inertial motion of material bodies, are discussed within the Drude–Lorentz (plasma) model of matter polarization. It is shown that an oscillatory motion of a point-like body, or wavelike motion in an extended body gives rise to electromagnetic fields with the same frequency as the frequency of the original motion, while shock-like movements of a point-like body generate electromagnetic fields with the characteristic (atomic scale) frequency of the bodies. The polarization of a rigid body induced by rotations is discussed in various circumstances. A uniform rotation produces a static electric field in a dielectric and a stationary current (and a static magnetic field) in a conductor. The latter corresponds to the gyromagnetic effect (while the former may be called the gyroelectric effect). Both fields are computed for a sphere and the gyromagnetic coefficient is derived. A non-uniform rotation induces emission of electromagnetic fields. The equations of motion for the polarization are linearized for slight non-uniformities of the angular velocity and solved both for a dielectric and a conducting sphere. The electromagnetic field emitted by a dielectric spherically shaped body in (a slightly) non-uniform rotation has the characteristic (atomic scale) frequency of the body (slightly shifted by the uniform part of the angular frequency). In the same conditions, a conducting sphere emits an electromagnetic field whose frequency is double the uniform part of the angular frequency.     

Interaction of the quantized electromagnetic field with atoms in the presence of dispersing and absorbing dielectric bodies

A general theory of the interaction of the quantized electromagnetic field with atoms, in the presence of dispersing and absorbing dielectric bodies of given Kramers-Kronig consistent permittivities, is developed. It is based on a source-quantity representation of the electromagnetic field, in which the electromagnetic-field operators are expressed in terms of a continuous set of fundamental bosonic fields via the Green tensor of the classical problem. Introducing scalar and vector potentials, the formalism is extended to include in the theory the interaction of the quantized electromagnetic field with additional atoms. Both the minimal-coupling scheme and the multipolar-coupling scheme are considered. The theory replaces the standard concept of mode decomposition, which fails for complex permittivities. It enables us to treat the effects of dispersion and absorption in a consistent way and to give a unified approach to the atom-field interaction, without any restriction to a particular interaction regime in a particular frequency range. All relevant information about the dielectric bodies, such as form and intrinsic dispersion and absorption, is contained in the Green tensor. The application of the theory to the spontaneous decay of an excited atom in the presence of dispersing and absorbing bodies is addressed.     

Theoretical and Mathematical Physics

A new effective method for solving three-dimensional problems of electromagnetic wave diffraction by impedance bodies with irregular boundaries is proposed. The method offers a high rate of convergence. Examples of solving the problems of wave scattering by bodies of revolution are given, and results illustrating the rate of convergence of a computational algorithm for bodies of various shapes are presented. The impedance approximation is shown to be valid for simulation of scattering characteristics of bodies with an insulating coating even when the boundary has irregularities and the refractive index of the coating is not too high. Various ways of characterizing “black bodies” and the results of studying their scattering characteristics are discussed.     

Some new radiating Kerr-Newman solutions

Three exact non-static solutions of Einstein-Maxwell equations corresponding to a field of flowing null radiation plus an electromagnetic field are presented. These solutions are non-static generalizations of the well known Kerr-Newman solution. The current vector is null in all the three solutions. These solutions are the electromagnetic generalizations of the three generalized radiating Kerr solutions discussed by Vaidya and Patel. The solutions discussed by us describe the exterior gravitational fields of rotating radiating charged bodies. Many known solutions are derived as particular cases.     

Balanced Flux Concentrators and Their Application for Reduction of Electromagnetic Forces in Magnetic Systems

Technical Physics - Magnetic flux concentrators, viz., bodies with radial cuts introduced into the field of a magnet, substantially affect the magnitude and distribution of electromagnetic forces...     

基于电磁振动上料的茶梗和昆虫异物近红外光谱和荧光图像在线检测研究

茶叶是大众青睐的健康饮品之一,但茶叶在机器采收和加工过程中,容易混入茶梗和昆虫异物,污染茶叶、影响其质量安全,是未来应防范和检测的重点。X射线成像技术,根据食品基质和异物的密度差实施检测,广泛适用于金属异物并延伸至高密度塑料,但对于茶梗、昆虫这类低密度有机异物尚不适用,所以迫切需要研发新型无损检测技术和方法。针对片状茶叶重叠、遮掩异物的问题,提出了电磁振动上料辅助近红外光谱和荧光图像的检测方案,进行绿茶中的内源性异物茶梗和外源性异物昆虫的在线检测研究。通过电磁振动上料辅助近红外光谱和荧光成像系统,采集了600～1 050 nm范围的近红外光谱600条和RGB-N四通道图像各65幅。采用451条光谱进行建模,其余149条光谱作为预测集,评估模型的性能,比较了去趋势(Detrending)、多元散射校正(MSC)、标准正态变换(SNV)、变权重正态变换(VSN)、迭代自适应加权惩罚最小二乘法(airPLS)、不对称最小二乘法(ALS)、光程估计与校正(OPLEC)等不同光谱预处理方法的处理效果,其中OPLEC能较好地消除散射效应,偏最小二乘判别分析(PLS-DA)模型的正确识别率由78%提...     

Physical properties of the 6D STMC Universe

A 6D Space-Time-Mass-Charge (STMC) Theory is taken to see how far the physical properties of the 4D Space-Time Universe can be explained by the geometrical quantities of the extra dimensions. The equation of state for the macroscopic bodies is obtained, and the general properties of the electromagnetic field can be studied.     

Diffraction of electromagnetic waves in a three-dimensional magnetodielectric body of arbitrary shape

A numerical method of solving the problem of the diffraction of electromagnetic waves by a three-dimensional magnetodielectric body of arbitrary shape in the resonance frequency region is proposed. The method is applied in the form of a FORTRAN software package for calculating the components of the diffraction field of bodies with different electrodynamic and geometrical parameters. The directivity parameters of some bodies of complex shape are given.V. D. Kuznetsov Siberian Physicotechnical Institute, Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 87–91, June, 1995.     

The field of a point source near planar and cylindrical boundaries of a metamaterial

The properties of the two-dimensional electromagnetic fields excited by a filamentary source located near planar and cylindrical boundaries of bodies made of metamaterials with their permittivity and permeability close to minus one are considered. The subwavelength field localization effects, the phenomena associated with the resonances of surface waves, and the nonresonant field enhancement effects are investigated.     

Field induced in inhomogeneous spheres by external sources. I. The scalar case

The evaluation of acoustic or electromagnetic fields induced in the interior of inhomogeneous penetrable bodies by external sources is based on well-known volume integral equations; this is particularly true for bodies of arbitrary shape and/or composition, for which separation of variables fails. In this paper the investigation focuses on acoustic (scalar fields) in inhomogeneous spheres of arbitrary composition, i.e., with r-, theta- or even phi-dependent medium parameters. The volume integral equation is solved by a hybrid (analytical-numerical) method, which takes advantage of the orthogonal properties of spherical harmonics, and, in particular, of the so-called Dini's expansions of the radial functions, whose convergence is optimized. The numerical part comes at the end; it involves the evaluation of certain definite integrals and the matrix inversion for the expansion coefficients of the solution. The scalar case treated here serves as a steppingstone for the solution of the more difficult electromagnetic problem.     

Gravitation in flat space. principle of equivalence for massive bodies of gravitational structure

It is shown that in a new nonmetrical nonlinear theory of gravitation in flat space [1, 2], satisfying the four classical effects of the general theory of relativity and the weak principle of equivalence for massive bodies of electromagnetic structure, the weak principle of equivalence is also satisfied for massive bodies of gravitational structure.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 26–32, May, 1979.     

Equivalent-source method and calculation of currents induced in electron-emitting bodies

Currents flowing in metallic bodies from the surface of which electrons are being emitted intensely into the exterior space are calculated by the method of equivalent sources of electromagnetic fields.Saint Petersburg State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 37, No. 3, pp. 363–374, March, 1994.     

First-principles theory of van der Waals forces between macroscopic bodies

We present a first-principles method for the determination of the van der Waals interactions for a collection of finite-sized macroscopic bodies. The method is based on fluctuational electrodynamics and a rigorous multiple-scattering method for the electromagnetic field. As such, the method takes fully into account retardation, many-body, multipolar, and near-fields effects. By application of the method to the case of two metallic nanoparticles, we demonstrate the breakdown of the standard 1/r(2) distance law as the van der Waals force decays exponentially with distance when the nanoparticles are too close or too far apart.     

Electromagnetic wave scattering by small bodies

A reduction of the Maxwell's system to a Fredholm second-kind integral equation with weakly singular kernel is given for electromagnetic (EM) wave scattering by one and many small bodies. This equation is solved asymptotically as the characteristic size of the bodies tends to zero. The technique developed is used for solving the many-body EM wave scattering problem by rigorously reducing it to solving linear algebraic systems, completely bypassing the usage of integral equations. An equation is derived for the effective field in the medium, in which many small particles are embedded. A method for creating a desired refraction coefficient is outlined.