Publications by authors named "Frumin L"

We calculate the light transmission by a subwavelength plasmonic array using the boundary element method for parallel cylinders with different cross-sections: circular or elliptic with axis ratio 4:1. We demonstrate that plasmonic resonance is sharper for the case of horizontal ellipses. This structure is susceptible to refractive index variations in the media since the high derivatives of reflection and transmission coefficients are near the angle of total internal reflection.

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A plasmonic grating consisting of parallel gold or silver nanowires on the glass substrate is an excellent sensor for refractive index measurement of a gas or liquid medium. We suggest measuring the local field in a gap between the wires to increase the sensitivity. The local electric field contains more information on the environment since it includes the evanescent waves.

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The discrete dipoles approximation method is exploited to study light scattering near a cylindrical cavity, made in an absorbing plasmonic surrounding medium. To the best of our knowledge, this is the first use of the method for the metal background. Our two-dimensional numerical simulation of the local fields demonstrates a good performance of the approach.

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The nonlinear Schrödinger equation (NLSE) is often used as a master path-average model for fiber-optic transmission lines. In general, the NLSE describes the co-existence of dispersive waves and soliton pulses. The propagation of a signal in such a nonlinear channel is conceptually different from linear systems.

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The attractive plasmonic force between two metallic walls due to electromagnetic wave in the slit has been studied earlier for parallel plates and normal incidence. In present paper the effects of imperfectly adjusted plates and laser beam are analyzed. The change of force for non-parallel plates is shown to be of the first order in angle when the wedge is oriented along wave propagation and of the second order for the transverse case.

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Remarkable mathematical properties of the integrable nonlinear Schrödinger equation (NLSE) can offer advanced solutions for the mitigation of nonlinear signal distortions in optical fiber links. Fundamental optical soliton, continuous, and discrete eigenvalues of the nonlinear spectrum have already been considered for the transmission of information in fiber-optic channels. Here, we propose to apply signal modulation to the kernel of the Gelfand-Levitan-Marchenko equations that offers the advantage of a relatively simple decoder design.

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The scattering of a wave by a cylindric object hidden within the dielectric is studied. The total reflection is frustrated because of the scattering. Magnetic and electric fields at the dielectric surface and the energy flux are calculated by the modified boundary element method at near-field and far-field distances.

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The scattering of plane evanescent waves by a cylinder is studied. The Green function for the Helmholtz equation for two dielectrics with flat interface is found and applied for the numerical calculation of the scattered field by the boundary elements method. The Green function keeps close track of scattering, including multiple reflections.

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The inverse scattering problem for the one-dimensional Helmholtz wave equation is studied. The equation is reduced to a Fresnel set that describes multiple bulk reflection and is similar to the coupled-wave equations. The inverse scattering problem is equivalent to coupled Gel'fand-Levitan-Marchenko integral equations.

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A comparatively new procedure is described for the nonlinear electrophoresis of proteins. Movement and separation of complexes formed by proteins and ionic detergents is first experimentally demonstrated for SDS rainbow colored protein molecular weight markers (Amersham). This result was revealed by SDS-PAGE in an asymmetric zero average pulsed electric field with a peak amplitude of up to 300 V cm(-1) and a frequency of 100 Hz.

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Nonlinear focusing of DNA macromolecules.

Phys Rev E Stat Nonlin Soft Matter Phys

August 2001

The present paper reports the nonlinear electrophoretic focusing techniques developed after an original idea by Chacron and Slater [Phys. Rev. E 56, 3436 (1997)].

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A new approach to focusing DNA molecules in a nonuniform electric field based on nonlinear mobility (L. L. Frumin, S.

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Effects of nonlinear dependence drift velocity of (double-stranded) DNA vs. electric field strength were investigated. In comparatively weak fields, the molecular drift velocity is proportional to the external electric field, while in strong fields there is additional nonlinear component.

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The focusing problem under isoelectric focusing has been solved analytically precisely. The solutions determine the law of the fraction moving and narrowing in the instant electric field gradient. This is especially actually because of developing the calculation methods in electrophoretical experiment.

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A water treatment AKBA-I unit intended for the renal centers was tried. The unit includes a clarifier, an adsorber, a softener, a reflux osmotic separator and electronic systems for the control of hydrodynamic processes. The trials demonstrated the unit to be highly effective as regards the removal from water of salts of hardness, of iron, potassium, oxidizable substances and active chlorine.

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The results of the experiments for the objective evaluation on a model system of the protective effect of deodorant gaskets on colostomy patients are given. It has been determined that the deodorant capacity of the above gaskets is more than two times higher than that of its "washer filter" analog manufactured by the foreign "Coloplast" company.

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Antithrombotic properties are induced in polymers used in vascular surgery by modifying their surface chemically by introducing heparin by means of quaternary bases. The authors have studied the interaction of heparin with quaternary polyvinylpyridinium bromide. Optimal conditions for obtaining this complex have been established.

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