Plasma dispersion of multisubband electron systems over liquid helium

Density-density response functions are evaluated for nondegenerate multisubband electron systems in the random-phase approximation for arbitrary wave number and subband index. We consider both quasi-two-dimensional and quasi-one- dimensional systems for electrons confined to the surface of liquid helium. The dispersion relations of longitudinal intrasubband and transverse intersubband modes are calculated at low temperatures and for long wavelengths. We discuss the effects of screening and two-subband occupancy on the plasmon spectrum. The characteristic absorption edge of the intersubband modes is shifted relatively to the single-particle intersubband separation and the depolarization shift correction can be significant at high electron densities

Coupled phonon-ripplon modes in a single wire of electrons on the liquid-helium surface

The coupled phonon-ripplon modes of the quasi-one-dimensional electron chain on the liquid helium sutface are studied. It is shown that the electron-ripplon coupling leads to the splitting of the collective modes of the wire with the appearance of low-frequency modes and high-frequency optical modes starting from threshold frequencies. The effective masses of an electron plus the associated dimple for low frequency modes are estimated and the values of the threshold frequencies are calculated. The results obtained can be used in experimental attempts to observe the phase transition of the electron wire into a quasi-ordered phase.Comment: 5 pages, 1 figure, Physical Review (in press

Pseudo-epsilon expansion and the two-dimensional Ising model

Starting from the five-loop renormalization-group expansions for the two-dimensional Euclidean scalar \phi^4 field theory (field-theoretical version of two-dimensional Ising model), pseudo-\epsilon expansions for the Wilson fixed point coordinate g*, critical exponents, and the sextic effective coupling constant g_6 are obtained. Pseudo-\epsilon expansions for g*, inverse susceptibility exponent \gamma, and g_6 are found to possess a remarkable property - higher-order terms in these expansions turn out to be so small that accurate enough numerical estimates can be obtained using simple Pade approximants, i. e. without addressing resummation procedures based upon the Borel transformation.Comment: 4 pages, 4 tables, few misprints avoide

Interfering Doorway States and Giant Resonances. II: Transition Strengths

The mixing of the doorway components of a giant resonance (GR) due to the interaction via common decay channels influences significantly the distribution of the multipole strength and the energy spectrum of the decay products of the GR. The concept of the partial widths of a GR becomes ambiguous when the mixing is strong. In this case, the partial widths determined in terms of the $K$- and $S$-matrices must be distinguished. The photoemission turns out to be most sensitive to the overlapping of the doorway states. At high excitation energies, the interference between the doorway states leads to a restructuring towards lower energies and apparent quenching of the dipole strength.Comment: 17 pages, LaTeX, 5 figures as JPEG, to appear in PRC (July 1997

Structuring meat systems using natural biopolymers

The features of the structure and properties of raw materials, which are a source of biopolymers of natural origin are presented. The main focus of the theoretical part is paid to the study of the process of structuring of biopolymers (proteins and polysaccharides). Practical approbation was carried out on the example of meat-containing meat and meat chopped products and semi-finished product

JIT Philosophy in Modern Management Cost Accounting and Performance Management Systems

Currently, traditional cost accounting methods are losing their relevance. Modern production environment is unpredictable and customer-oriented. Product life cycle becomes shorter, and consumers’ tastes are more capricious and fickle. All these factors suggest the need for flexible and adaptive control schemes.Successful decision-making is determined by well-built cost accounting system. The article proposes on the basis of the symbiosis of “just-in-time” approach, adherence to the principles of continuous improvement, and cost accounting methods — Kaizen-costing, standard-costing, target-costing, time-driven activity based costing, backflush accounting and value stream costing — to develop business performance management system that meets the needs of the modern business environment. The principles of continuous improvement, integrated into «Just In Time” management system, expand the horizon of opportunities for strategic management accounting. Zero-inventory philosophy, combined with flexible and adaptable management schemes, can also provide a powerful competitive advantage. The article recommends a system of key performance indicators to monitor the implementation of “Just in Time” philosophy in the symbiosis with these cost accounting methods. Zero-inventory approach has a number of drawbacks. However, integration of concepts with advanced cost accounting techniques will partly offset these shortcomings.The purpose of the article is to study the possibility of integration of «Just in Time” philosophy and advanced cost accounting methods, with respect to their features and peculiarities. The theoretical basis is the hypothesis of improving business performance management system based on “Just in Time” management approach, through its integration with the principles of continuous improvement and modern management approaches, quality assurance and approval.The main result of the article is an enhanced management accounting tools that allow to respond to changes in the environment of the company, develop measures aimed at adapting to these changes and ensuring compliance with the company’s strategy

Formation of bound states of electrons in spherically symmetric oscillations of plasma

We study spherically symmetric oscillations of electrons in plasma in the frame of classical electrodynamics. Firstly, we analyze the electromagnetic potentials for the system of radially oscillating charged particles. Secondly, we consider both free and forced spherically symmetric oscillations of electrons. Finally, we discuss the interaction between radially oscillating electrons through the exchange of ion acoustic waves. It is obtained that the effective potential of this interaction can be attractive and can transcend the Debye-Huckel potential. We suggest that oscillating electrons can form bound states at the initial stages of the spherical plasma structure evolution. The possible applications of the obtained results for the theory of natural plasmoids are examined.Comment: 9 pages in LaTeX2e, no figures; paper was significantly modified, 2 new references added, some inessential mathematics was removed, many typos were corrected; final variant to be published in Physica Script

Interfering Doorway States and Giant Resonances. I: Resonance Spectrum and Multipole Strengths

A phenomenological schematic model of multipole giant resonances (GR) is considered which treats the external interaction via common decay channels on the same footing as the coherent part of the internal residual interaction. The damping due to the coupling to the sea of complicated states is neglected. As a result, the formation of GR is governed by the interplay and competition of two kinds of collectivity, the internal and the external one. The mixing of the doorway components of a GR due to the external interaction influences significantly their multipole strengths, widths and positions in energy. In particular, a narrow resonance state with an appreciable multipole strength is formed when the doorway components strongly overlap.Comment: 20 pages, LaTeX, 3 ps-figures, to appear in PRC (July 1997

Scalar second order evolution equations possessing an irreducible sl2_2-valued zero curvature representation

We find all scalar second order evolution equations possessing an sl$_2$-valued zero curvature representation that is not reducible to a proper subalgebra of sl$_2$. None of these zero-curvature representations admits a parameter.Comment: 10 pages, requires nath.st