Low-frequency noise in Schottky-gate field-effect transistors

A three-section analytic model of a Schottky-gate field-effect transistor is used to calculate the drain-current modulation sensitivity to low-frequency fluctuations in various regions of the active layer. The examined noise sources in the conducting channel and in the gate depletion region are fluctuations of the carrier and bound-charge concentrations, whose spectra can include generation-recombination and flicker components. The theoretical results are compared with measurements of low-frequency current noise.Presented at All-Union Coordinating Conference Low-Frequency Noise in Semiconductor Devices (Chernogolovka, Moscow Region, June, 1991).St. Petersburg State Technical University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 36, No. 12, pp. 1118–1127, December, 1993.     

Analysis of oligospirostanosides in a suspension culture of Dioscorea deltoidea cells by high-performance liquid chromatography

A method has been developed for the quantitative determination of oligospirostanosides in a culture ofDioscorea deltoidea cells with the aid of HPLC on a LiChrosorb RP-18 column. Elution was performed with acetonitrile-water (50–75%) with detection at 207 nm. A. N. Bakh Institute of Biochemistry, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 549–551, July–August, 1988.     

Gas electron diffraction study of the geometric structure of triallylborane molecule

The main structural parameters of the triallylborane molecule having the C ₃ symmetry were determined by gas electron diffraction and quantum-chemical calculations at the MP2/6-31G(d,p) and B3LYP/6-31G(d,p) levels. The parameters calculated by the MP2/6-31G(d,p) method are in better agreement with the experimental data than those calculated by the B3LYP/6-31G(d,p) method.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 98–101, January, 2005.     

Measurement of the magnetomechanical effect in a gas discharge

The centrifugal dipole moments of the methane molecule are numerically calculated and their behavior at large quantum numbers of the total angular momentum of the molecule are analyzed.     

The formation of nalidixic acid dimers and excimers in aqueous solutions

The influence of optical excitation on the formation of nalidixic acid dimers and excimers in aqueous media in the ground and excited states was studied. Quantum-chemical calculations of the total energy of monomers and dimers were performed. The spectral-luminescent characteristics of pairs of nlqH molecules were measured, and changes in charges on atoms in the ground and excited states were estimated.     

The genus and the category of configuration spaces

In this paper configuration spaces of smooth manifolds are considered. The accent is made on actions of certain groups (mostly p-tori) on this spaces by permuting their points. For such spaces the cohomological index, the genus in the sense of Krasnosel'skii-Schwarz, and the equivariant Lyusternik-Schnirelmann category are estimated from below, and some corollaries for functions on configuration spaces are deduced.     

Polynomial deformations of the Lie algebrasl(2) in problems of quantum optics

It is shown that specific (polynomial) deformations of Lie algebras arise naturally as dynamical symmetry algebrasg ^ds of second-quantized models with nonquadratic HamiltoniansH invariant with respect to certain groupsG ^inv(H). Such deformationssl _d(2) of the Lie algebrasl(2) are found in a number of models of quantum optics (multiphoton processes, generalized Dicke model, and frequency conversion), and ways to apply thesl(2) formalism to the solution of physics problems are indicated.P. N. Lebedev Physics Institute, Russian Academy of Sciences. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 95, No. 1, pp. 3–19, April, 1993.     

Crystal and molecular structure and luminescence properties of the europium trifluoroacetate complex with dipyridyl

The crystal structure of [Eu(Dipy)(TFA)₃(H₂O)₃] · Dipy (where TFA^? is the trifluoroacetate anion and Dipy is, 2,2′-dipyridyl) has been studied by X-ray diffraction. The coordination polyhedron of the europium atom is a distorted square antiprism [EuO₆N₂] with the nonplanar quadrilateral faces. The coordinated and non-coordinated dipyridyl molecules are linked pairwise through π stacking interactions into an infinite pile with an overlap of up to 50% of the molecular surface areas. An increase in the luminescence intensity of the compound upon its UV irradiation is explained.     

Dynamical equations for the quantum product on a symplectic space in affine coordinates

We derive a system of dynamical equations for an associative noncommutative product of functions on a symplectic space. This system is explicitly solved in semiclassical approximation.Translated from Matematicheskie Zametki, vol. 77, no. 1, 2005, pp. 42–52.Original Russian Text Copyright © 2005 by O. N. Grigorev, M. V. Karasev.This revised version was published online in April 2005 with a corrected issue number.