Motion and radiation of a charge in a plane wave and a magnetic field

The motion and radiation of an electron moving in the field of a plane wave of elliptical polarization and a magnetic field is considered. By the methods of classical and quantum theory, the effect of the plane-wave polarization on the characteristics of the particle motion and radiation is investigated. Some particular cases are considered.Translated from Izvestiya Vysshikh Uchebnykh Zavedeniis Fizika, No. 10, pp. 70–74, October, 1978.     

Analogies between a Meniscus and a Cantilever

Systematic and quantitative analyses of exact analogies between a meniscus and an elastica are performed. It is shown that the two governing equations take the same style after coordinate translation and scale transformation. The morphologies of the liquid bridge and the cantilever are calculated in terms of elliptic integrations, which can be reduced to the same shape,after converting the boundary conditions. The present analyses can make us grasp the nature of this physical phenomenon deeply and show some inspiration for designing the analogy experiments. Moreover, the calculated results are helpful to engineering applications, such as design and fabrication of MEMS, and micro-manipulations in micro/nano- technology.     

Tunnelling process between a semiconductor or a metal and a polymer

The tunnelling lifetime of an electron lying in a p-type orbital localised at a given distance from a semiconductor or a metal is calculated by using Bardeen's method. It is then shown that even in the absence of broad bands, the hole injection process from semiconductors and metals into polymers should follow a Fowler-Nordheim dependence, provided that the current is not bulk-limited. In the semiconductor case, the current can be expressed by a fully analytical formula, and by an approximate one in the case of a metal. It is demonstrated that the effective Fowler-Nordheim barrier is not the mere difference between the metal work function or the semiconductor electron affinity and the HOMO level of the polymer, but a simple function of both levels. Received 6 April 2001 and Received in final form 29 May 2001     

Casimir Interaction between a plate and a cylinder

We find the exact Casimir force between a plate and a cylinder, a geometry intermediate between parallel plates, where the force is known exactly, and the plate sphere, where it is known at large separations. The force has an unexpectedly weak decay approximately L/[H3 ln(H/R)] at large plate-cylinder separations H (L and R are the cylinder length and radius), due to transverse magnetic modes. Path integral quantization with a partial wave expansion additionally gives a qualitative difference for the density of states of electric and magnetic modes, and corrections at finite temperatures.     

Solution electronic spectra of brassinosteroid and a synthesized conjugate of a steroid and a fluorescent label

Electronic absorption spectra of 24-epicastasterone and 24-epibrassinolide solutions have been recorded and analyzed. The long-wavelength band in solution spectra of the former steroid with maxima in the region 292–286 nm is assigned to the electronic nπ*-transition of a carbonyl chromophore. The latter steroid contains an O-C=O group, for which the extinction coefficient in this spectral region is approximately one order of magnitude less. These differences can be used to identify the studied steroids. A method to synthesize the conjugate of 24-epicastasterone with a fluorescent label, dansylhydrazine, which shows intense fluorescence and absorption, is described. Absorption spectra of the label and conjugate in diethylether, tetrahydrofuran, ethanol, and acetonitrile solutions are practically independent of the solvent properties. The exceptions are solutions of the conjugate in hexane and water. All investigated solutions of label and conjugate show intense fluorescence. As the dielectric constant of the solvent increases, the fluorescence spectra shift to long-wavelength. The fluorescence energetic and time characteristics of both the label and conjugate are similar, which enables the conjugate to be used in developing a method for immunofluorescent analysis of the brassinosteroid 24-epicastasterone. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 1, pp. 74–78, January–February, 2008.     

Rigorous solution of a problem for a cylindrical cavity containing a ferrite and a dielectric

A rigorous solution is given for modes of TM_nmo type. The complex resonant frequency _n is expressed via a transcendental characteristic equation. Some particular cases are discussed.Read at the Third All-Union Conference on Ferrites, Leningrad, 23 October 1963.     

Entanglement between a photon and a quantum well

The lack of translational invariance perpendicular to the plane of a single quantum well causes equal probability for spontaneous emission to the left or right. Combining one emission path from the left and one from the right into a common detector leads to interference fringes for fundamentally indistinguishable paths corresponding to geometries where the same in-plane momentum is transferred to the quantum well. For all other paths, no interference is observed because of the entanglement between the photon and extended Bloch states of the many-body system. In multiple-quantum-well structures the interference can be controlled via the spacing between the wells.     

Plasmons and polaritons in a semi-infinite plasma and a plasma slab

Plasmon and polariton modes are derived for an ideal semi-infinite (half-space) plasma and an ideal plasma slab by using a general, unifying procedure, based on equations of motion, Maxwell's equations and suitable boundary conditions. Known results are re-obtained in much a more direct manner and new ones are derived. The approach consists of representing the charge disturbances by a displacement field in the positions of the moving particles (electrons). The dielectric response and the electron energy loss are computed. The surface contribution to the energy loss exhibits an oscillatory behaviour in the transient regime near the surfaces. The propagation of an electromagnetic wave in these plasmas is treated by using the retarded electromagnetic potentials. The resulting integral equations are solved and the reflected and refracted waves are computed, as well as the reflection coefficient. For the slab we compute also the transmitted wave and the transmission coefficient. Generalized Fresnel's relations are thereby obtained for any incidence angle and polarization. Bulk and surface plasmon-polariton modes are identified. As it is well known, the field inside the plasma is either damped (evanescent) or propagating (transparency regime), and the reflection coefficient for a semi-infinite plasma exhibits an abrupt enhancement on passing from the propagating regime to the damped one (total reflection). Similarly, apart from characteristic oscillations, the reflection and transmission coefficients for a plasma slab exhibit an appreciable enhancement in the damped regime.     

Conductance of a junction between a normal metal and a Berezinskii superconductor

The conductance of a junction between a normal metal and a superconductor having the symmetry proposed by Berezinskii is studied theoretically. The main feature of this symmetry is the odd frequency dependence of the anomalous Green’s function, which makes possible the s-wave triplet superconducting state (the Berezinskii superconductor). The Andreev reflection (which links positive and negative energies) is sensitive to the energetic symmetry; as a result, the conductance of the junction involving the Berezinskii superconductor is qualitatively different from the case of a conventional superconductor. Experimentally, the obtained results can be employed to test the possibility of the Berezinskii superconductivity proposed for Na _x CoO₂ and to identify the odd-ω component predicted for superconductor-ferromagnet systems.     

Cavitation in a lubrication flow between a moving sphere and a boundary

A heavy sphere is free to move inside a rotating horizontal cylinder filled with viscous liquid. The steady motion is essentially Stokesian, and the sphere rotates at a fixed location with a lubrication layer between the ball and the wall. The symmetry of the flow field suggests there will be no force to balance the normal component of the ball's weight. However, we show that a normal force can arise when a cavitation bubble is present. The bubble size was measured as a function of the cylinder rotation rate and agrees well with a model which uses the force and torque balances on the sphere.     

Conductance of a junction between a normal metal and a Berezinskii superconductor

The conductance of a junction between a normal metal and a superconductor having the symmetry proposed by Berezinskii is studied theoretically. The main feature of this symmetry is the odd frequency dependence of the anomalous Green’s function, which makes possible the s-wave triplet superconducting state (the Berezinskii superconductor). The Andreev reflection (which links positive and negative energies) is sensitive to the energetic symmetry; as a result, the conductance of the junction involving the Berezinskii superconductor is qualitatively different from the case of a conventional superconductor. Experimentally, the obtained results can be employed to test the possibility of the Berezinskii superconductivity proposed for Na _x CoO₂ and to identify the odd-ω component predicted for superconductor-ferromagnet systems. The text was submitted by the author in English.     

Solving a relativistic quasipotential equation for a superposition of a nonlocal separable and a local quasipotential

Within the relativistic quasipotential approach to quantum field theory, a method is developed for solving a finite-difference quasipotential equation for the case where a total quasipotential describing the interaction of two relativistic spinless particles of unequal masses is a superposition of a nonlocal separable and a local quasipotential. The cases are investigated where the local component of the total interaction—it is assumed to be known—either admits or does not admit the existence of bound states. This makes it possible to obtain an exact expression for the increment of the phase shift, to determine the conditions of the existence of bound states, and to give a generalization of the Levinson theorem.     

Fabrication and characterization of a vertical pillar structure including a self-assembled quantum dot and a quantum well

We fabricate and characterize a novel vertical pillar structure including a self-assembled InAs quantum dot (QD) and an InGaAs quantum well (QW). The vertical current through both the InAs QD and an electrostatically defined QD made in the InGaAs QW can be measured by adjusting the position of the InGaAs QD in the QW plane relative to the InAs QD with two side-gate voltages applied independently. We study optical response of the current through the vertical double QD by irradiating light, which is assumed to be mainly absorbed in the InAs QDs. We successfully probe a time-dependent energy level shift due to the Coulomb interaction from holes trapped in the vicinity of the pillar.     

点电荷与介质球系统电势的计算和讨论

计算了点电荷与介质球系统的电势．指出点电荷与导体球、点电荷与无限大导体平面或介质分界平面均匀外电场中有导体球或介质球系统的电势都可由点电荷与介质球系统的电势给出。     

Structure and electronic properties of a heterojunction between a single wall carbon nanotube and a TiC cluster

Atomic structures and electronic properties of heterojunctions of Ti-TiC and TiC-single wall carbon nanotube, Ti₄₈-Ti₁₉C₂₆ and Ti₁₉C₂₄-C₃₀, are studied by the first principles calculation based on the density functional theory. At the junctions, these substrates are smoothly connected with each other and keep their original structures and electronic properties. The structures of the junctions obtained in the present work give a realistic model to ab initio study for electronic transport properties through the junction of a carbon nanotube and an electrode.