Enhanced Transmission of Light and Particle Waves through Subwavelength Nanoapertures by Far-Field Interference

Subwavelength aperture arrays in thin metal films can enable enhanced transmission of light and matter (atom) waves. The phenomenon relies on resonant excitation and interference of the plasmon or matter waves on the metal surface. We show a new mechanism that could provide a great resonant and nonresonant transmission enhancement of the light or de Broglie particle waves passed through the apertures not by the surface waves, but by the constructive interference of diffracted waves (beams generated by the apertures) at the detector placed in the far-field zone. In contrast to other models, the mechanism depends neither on the nature (light or matter) of the beams (continuous waves or pulses) nor on material and shape of the multiple-beam source (arrays of 1-D and 2-D subwavelength apertures, fibers, dipoles or atoms). The Wood anomalies in transmission spectra of gratings, a long standing problem in optics, follow naturally from the interference properties of our model. The new point is the prediction of the Wood anomaly in a classical Young-type two-source system. The new mechanism could be interpreted as a non-quantum analog of the superradiance emission of a subwavelength ensemble of atoms (the light power and energy scales as the number of light-sources squared, regardless of periodicity) predicted by the well-known Dicke quantum model.Comment: Revised version of MS presented at the Nanoelectronic Devices for Defense and Security (NANO-DDS) Conference, 18-21 June, 2007, Washington, US

Nanostratification of optical excitation in self-interacting 1D arrays

The major assumption of the Lorentz-Lorenz theory about uniformity of local fields and atomic polarization in dense material does not hold in finite groups of atoms, as we reported earlier [A. E. Kaplan and S. N. Volkov, Phys. Rev. Lett., v. 101, 133902 (2008)]. The uniformity is broken at sub-wavelength scale, where the system may exhibit strong stratification of local field and dipole polarization, with the strata period being much shorter than the incident wavelength. In this paper, we further develop and advance that theory for the most fundamental case of one-dimensional arrays, and study nanoscale excitation of so called "locsitons" and their standing waves (strata) that result in size-related resonances and related large field enhancement in finite arrays of atoms. The locsitons may have a whole spectrum of spatial frequencies, ranging from long waves, to an extent reminiscent of ferromagnetic domains, -- to super-short waves, with neighboring atoms alternating their polarizations, which are reminiscent of antiferromagnetic spin patterns. Of great interest is the new kind of "hybrid" modes of excitation, greatly departing from any magnetic analogies. We also study differences between Ising-like near-neighbor approximation and the case where each atom interacts with all other atoms in the array. We find an infinite number of "exponential eigenmodes" in the lossless system in the latter case. At certain "magic" numbers of atoms in the array, the system may exhibit self-induced (but linear in the field) cancellation of resonant local-field suppression. We also studied nonlinear modes of locsitons and found optical bistability and hysteresis in an infinite array for the simplest modes.Comment: 39 pages, 5 figures; v2: Added the Conclusions section, corrected a typo in Eq. (5.3), corrected minor stylistic and grammatical imperfection

Anisotropic generalization of Stinchcombe's solution for conductivity of random resistor network on a Bethe lattice

Our study is based on the work of Stinchcombe [1974 \emph{J. Phys. C} \textbf{7} 179] and is devoted to the calculations of average conductivity of random resistor networks placed on an anisotropic Bethe lattice. The structure of the Bethe lattice is assumed to represent the normal directions of the regular lattice. We calculate the anisotropic conductivity as an expansion in powers of inverse coordination number of the Bethe lattice. The expansion terms retained deliver an accurate approximation of the conductivity at resistor concentrations above the percolation threshold. We make a comparison of our analytical results with those of Bernasconi [1974 \emph{Phys. Rev. B} \textbf{9} 4575] for the regular lattice.Comment: 14 pages, 2 figure

Lymphoproliferative Syndrome in Pediatrist and Infectiologist Practice

Chronic Epstein-Barr virus infection (CEBVI) is the frequent infectious cause of lymphoproliferative syndrome (LPS) in children. Purpose: To characterize the most informative CEBVI diagnostic criteria in children according to age and disease form. Materials and Methods: 168 children in age from 3 to 7 (116) and from 7 to 14 years old (52) with CEBVI (70) and chlamydiosis mixed CEBVI (98) were examined. Results: Antenatal, intranatal and postnatal risk groups in all patients were exposed. LPS was detected in 100% children and characterized by combination of generalized lymphadenopathy, hepatomegaly, splenomegaly with palatine and pharyngeal tonsil hypertrophy. Except LPS, CEBVI syndromal model was included intoxication syndrome, respiratory and gastrointestinal tracts, central nervous system (CNS), cardiovascular system affection and arthralgia syndrome. CEBI in young children was characterized by frequent risk groups, palatine tonsil hypertrophy, hepatomegaly, pharyngotonsillitis and CNS affection. In patients with mixed CEBVI, high frequency of risk groups, pharyngeal tonsil hypertrophy, hepatomegaly, splenomegaly, respiratory and gastrointestinal tract, CNS pathology was detected.Summary: Risk groups and clinical symptoms of CEBVI are the indication for ELISA and PCR examination

Study on the process of Fe (III) oxide fluorination

The article deals with a fundamentally new fluoride technology for obtaining fluoride materials, provides data on the kinetics of the process of fluorination of Fe oxide with fluorine, fluoride and ammonium bifluoride. The physical and chemical properties of obtained fluorides are shown: a study of the elemental composition, grain-size composition using the method of scanning electron microscopy and laser diffraction

МОДЕЛИРОВАНИЕ ВЛИЯНИЯ ВНУТРЕННИХ МЕХАНИЧЕСКИХ НАПРЯЖЕНИЙ НА СКОРОСТЬ РОСТА КИСЛОРОДНЫХ ПРЕЦИПИТАТОВ В КРЕМНИИ

In the work an approach to modeling the influence of mechanical stresses generated in a silicon matrix by an oxygen precipitate (SiO2) on the rates of the main processes determining the precipitation kinetics. The time dependences of the sizes of a spherical precipitate and the number of oxygen atoms inside it has been obtained and analyzed with the stress factor taken into account. Предложен подход для моделирования влияния механических напряжений, возникающих в системе «кремниевая матрица — кислородный преципитат (SiO2)», на скорость основных процессов,определяющих кинетику преципитации. Найдены и проанализированы полученные с учетом этого фактора зависимости от времени размеров сферическогопреципитата и количества атомов кислорода в нем.

Piezoresistivity and conductance anisotropy of tunneling-percolating systems

Percolating networks based on interparticle tunneling conduction are shown to yield a logarithmic divergent piezoresistive response close to the critical point as long as the electrical conductivity becomes nonuniversal. At the same time, the piezoresistivity or, equivalently, the conductivity anisotropy exponent $\lambda$ remains universal also when the conductive exponent is not, suggesting a purely geometric origin of $\lambda$. We discuss our results in relation to the nature of transport for a variety of materials such as carbon-black--polymer composites and RuO_2-glass systems which show nonuniversal transport properties and coexistence between tunneling and percolating behaviors.Comment: 6 pages, 3 figures, Added discussion on experiment

Controllability of 2D Euler and Navier-Stokes equations by degenerate forcing

We study controllability issues for the 2D Euler and Navier- Stokes (NS) systems under periodic boundary conditions. These systems describe motion of homogeneous ideal or viscous incompressible fluid on a two-dimensional torus T^2. We assume the system to be controlled by a degenerate forcing applied to fixed number of modes. In our previous work [3, 5, 4] we studied global controllability by means of degenerate forcing for Navier-Stokes (NS) systems with nonvanishing viscosity (\nu > 0). Methods of dfferential geometric/Lie algebraic control theory have been used for that study. In [3] criteria for global controllability of nite-dimensional Galerkin approximations of 2D and 3D NS systems have been established. It is almost immediate to see that these criteria are also valid for the Galerkin approximations of the Euler systems. In [5, 4] we established a much more intricate suf- cient criteria for global controllability in finite-dimensional observed component and for L2-approximate controllability for 2D NS system. The justication of these criteria was based on a Lyapunov-Schmidt reduction to a finite-dimensional system. Possibility of such a reduction rested upon the dissipativity of NS system, and hence the previous approach can not be adapted for Euler system. In the present contribution we improve and extend the controllability results in several aspects: 1) we obtain a stronger sufficient condition for controllability of 2D NS system in an observed component and for L2- approximate controllability; 2) we prove that these criteria are valid for the case of ideal incompressible uid (\nu = 0); 3) we study solid controllability in projection on any finite-dimensional subspace and establish a sufficient criterion for such controllability