Electro- and photoluminescence of compounds based on doped zinc sulfide in the 500–750-nm range

The influence of atmospheric passivation on the electro- and photoluminescent properties of ZnS powders doped with In and/or CuCl is investigated. The processes proceeding in the material during thermal doping with In and/or CuCl as well as participation of oxygen in forming the electro- and photoluminescent radiation centers are discussed. The possibility of creating electro- and photoluminophors based on ZnS that have a continuous spectrum in the visible range with the same spectral density is shown. An electroluminophor based on ZnS:In,Cu,Cl that emits radiation with practically the same spectral density in the 550–750-nm range has been created as well as a photoluminophor based on ZnS:In that emits similarly within the range 500 < < 700 nm.__________Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 1, pp. 90–93, January–February, 2005.     

Mechanism of photoluminescence excitation of Mn<Superscript>2+</Superscript> ions in ZnS crystals

The mechanisms of photoluminescence excitation of Mn²⁺ ions in ZnS crystals have been investigated on the basis of complex analysis of the temperature dependences of the photoluminescence and photoluminescence-excitation spectra of ZnS:Mn crystals. The activation energy of a manganese luminescence center was estimated at E_a = 0.17 ± 0.05 eV. It is shown that E_a represents an energy band with a width ΔE_a = 0.1 eV, within which a manganese luminescence center can experience radiationless recombination. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 6, pp. 788–793, November–December, 2005.     

Linear low-rank approximation and nonlinear dimensionality reduction

We present our recent work on both linear and nonlinear data reduction methods and algorithms: for the linear case we discuss results on structure analysis of SVD of column-partitioned matrices and sparse low-rank approximation; for the nonlinear case we investigate methods for nonlinear dimensionality reduction and manifold learning. The problems we address have attracted great deal of interest in data mining and machine learning.     

Semilinear parabolic equations involving measures and low regularity data

A detailed study of abstract semilinear evolution equations of the form is undertaken, where generates an analytic semigroup and is a Banach space valued measure depending on the solution. Then it is shown that the general theorems apply to a variety of semilinear parabolic boundary value problems involving measures in the interior and on the boundary of the domain. These results extend far beyond the known results in this field. A particularly new feature is the fact that the measures may depend nonlinearly and possibly nonlocally on the solution.

     

Fast topological analysis of 2D and 3D grids of data: application to the atoms in molecule (AIM) and the electron localization function (ELF)

The topological analysis of grids of data is used for determination of surfaces or volumes around maxima. The volumes are then related to chemical information such as atoms or bonds, and can be used for integration of local properties such as electronic population. The problem of global connectivity is reversed into the question of local connectivity yielding a linear scaling partition algorithm. Two packages are developed for a very fast analysis and partition of 2D or 3D grids of data, applications being made to C2H2, C2H4, C6H6, H2CO, and H2CS molecules using the Atoms in Molecule (AIM) or Electron Localization Function (ELF).     

Adaptive Correction of Errors in Residue Coupled MASH ΔΣ Modulators

MASH delta-sigma () modulators consist of a cascade of several lower order single-loop modulators. In an ideal cascade, the quantization error from all but the last stage are digitally canceled. The drawback with a cascaded design is the requirement of precise matching of contributions from different quantizers to cancel lower order quantization noise from intermediate delta-sigma stages. This paper presents a new, adaptive improvement to the residue coupled MASH delta sigma modulator. The adaptive corrections significantly reduce the sensitivity to analog imperfections. The result is a simple MASH delta-sigma modulator with high precision. Simulations of a 1-1 MASH circuit structure with errors and corrections are included to confirm the theory.     

Network Assisted Power Control for Wireless Data

The cellular telephone success story prompts the wireless communications community to turn its attention to other information services, many of them in the category of wireless data communications. One lesson of cellular telephone network operation is that effective power control is essential to promote system quality and efficiency. In recent we have applied microeconomic theories to power control taking into account notions of utility and pricing. Our earlier work has shown that this new approach to power control for wireless data performs better than traditional techniques applied for voice signals. However, the operating points of such a strategy result in an unfair equilibrium in that users operate with unequal signal-to-interference ratios. Further, the power control algorithms required to achieve such operating points are more complex than the simple signal-to-interference ratio balancing algorithms for voice. In this paper, we introduce a new concept, Network Assisted Power Control (NAPC) that maximizes utilities for users while maintaining equal signal-to-interference ratios for all users. The power control algorithm is easily implemented via signal-to-interference ratio balancing with the assistance of the network that broadcasts the common signal-to-interference ratio target.     

Buckling of a Timoshenko beam on elastic foundation with uncertain input data

A monotone dependence of the critical buckling load of a simplysupported Timoshenko–Mindlin beam both on the shear correctionfactor and on the stiffness of foundation is proved. Then theworst-scenario method is employed to find the ‘most dangerous’input data.     

QUALITATIVE THEORY OF THE KUKLES SYSTEMS:(Ⅰ) NUMBER OF CRITICAL POINTS

The special cubic system (a natural and simPlest generaIization of thequadratic system of C1ass (l) to cubic system)f.'x = yl y = --x 6y a,x' a2xy a,y' a#x' a,x'y a.xy' a,y' (1)was first studied by the Russian Mathematician I.S.KukIes [ll on the Ilecessaryand sufficient conditions fot O(0,0) to be a ccnter of (1). After [ll, the sameproblem and also the order of O as a fine fOcus were also studied iIl [2--l0] and[13-19], so (l) is now called as a "Kukles system". In l988-…     

-actions whose fixed data has a section

Given a collection of real vector bundles over a closed manifold , suppose that, for some is of the form , where is the trivial one-dimensional bundle. In this paper we prove that if is the fixed data of a -action, then the same is true for the Whitney sum obtained from by replacing by . This stability property is well-known for involutions. Together with techniques previously developed, this result is used to describe, up to bordism, all possible -actions fixing the disjoint union of an even projective space and a point.