scholarly journals Особенности описания импульсной электрической прочности полимерных диэлектриков

Author(s):  
Ю.Э. Адамьян ◽  
С.И. Кривошеев ◽  
С.Г. Магазинов

The scenario based on the macro molecules field ionization model is proposed to describe the polymer dielectrics pulse breakdown. The decisive role of the real dielectric space-field inhomogeneity on formation of the ionization “sources” and redistribution of charge carries is taken into account. The justification of the choice of the defining model parameters - energy gap width and frequency factor is carried out. The possibility of using these parameters to describe the pulse electric strength of polymers in both uniform and sharply non-uniform electric fields (on the example of polymethylmethaacrylate) is shown.

2000 ◽  
Vol 14 (07) ◽  
pp. 729-735
Author(s):  
L. DIDUKH ◽  
YU. DOVHOPYATY ◽  
YU. SKORENKYY

A new variant of the generalized Hartree–Fock approximation for calculation of single-particle Green function in the Hubbard model is proposed. The calculated single-particle energy spectrum allows to study metal–insulator transition. Dependences of the energy gap width and the polar states concentration on model parameters are obtained. Conditions of a metallic and an insulating state realisation are found.


1999 ◽  
Vol 4 ◽  
pp. 31-86 ◽  
Author(s):  
R. Katilius ◽  
A. Matulionis ◽  
R. Raguotis ◽  
I. Matulionienė

The goal of the paper is to overview contemporary theoretical and experimental research of the microwave electric noise and fluctuations of hot carriers in semiconductors, revealing sensitivity of the noise spectra to non-linearity in the applied electric field strength and, especially, in the carrier density. During the last years, investigation of electronic noise and electron diffusion phenomena in doped semiconductors was in a rapid progress. By combining analytic and Monte Carlo methods as well as the available experimental results on noise, it became possible to obtain the electron diffusion coefficients in the range of electric fields where inter-electron collisions are important and Price’s relation is not necessarily valid. Correspondingly, a special attention to the role of inter-electron collisions and of the non-linearity in the carrier density while shaping electric noise and diffusion phenomena in the non-equilibrium states will be paid. The basic and up-to-date information will be presented on methods and advances in this contemporary field - the field in which methods of non-linear analytic and computational analysis are indispensable while seeking coherent understanding and interpretation of experimental results.


Author(s):  
K. E. Stupak ◽  

The article deals with analyzing the main streams of the education policy in Finland, which reflect the relationship between a person and society in modern socio–economic conditions. Such policy directs the system of education to change the person and his mind himself. Finland using its education system, has long before been concerned about preparing people for the future by reforming approaches to teaching in schools and higher education institutions. As a result, it has achieved world–wide recognition and top positions in various ratings have resulted. Therefore, today there is a great interest of scientists in certain issues of education functioning in Finland. Thus, G. Androshchuk, V. Butova. I. Zhernokleeva, T. Pushkareva and others study in their works the purpose and decisive role of Finland's education policy in the development of the education system. S. Grinyuk and V. Zagvozdkin pay attention to the practical the steps of reforming the Finnish system of education. T. Drobyshevsk investigates the system of providing educational services in Finland as a sector of knowledge production. L. Volynets, P. Kukharchuk consider the principles of the state education policy of Finland. L. Smolskaya examines the role of the state policy in implementing the "Finnish phenomenon"; P. Basyliuk and Yu. Kulykova, focus attention on the study of the evolution of the system of higher education in Finland; O. Scherbak reveals peculiarities of vocational education and training.


Author(s):  
Dunja Apostolov-Dimitrijevic

This paper explains political democratization in Post-Milosevic Serbia, utilizing two different accounts of the democratization process: one rooted in the rational choice framework and the other in structuralism. While rational choice explains the decisive role of political leadership in overcoming path dependence, the structuralist explanations show the transnational linkages that encourage democratization in the face of domestic setbacks. This particular debate between the two types of explanations represents the larger debate concerning the role of internal factors and external linkages in propelling democratization in transitional societies. The paper concludes by integrating the two sets of explanations offered by each theoretical perspective, in order to develop a coherent understanding of Serbia's democratization.   Full text available at: https://doi.org/10.22215/rera.v9i1.240


BMC Zoology ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Eva de la Peña ◽  
Javier Pérez-González ◽  
José Martín ◽  
Giovanni Vedel ◽  
Juan Carranza

Abstract Background In polygynous mammals, signalling may play a decisive role in mating behavior, mediating the intensity of male fights and female mate choice. During the rutting season, male red deer may show a visible dark patch in their ventral fur. Recently, this patch has been suggested to act as a flexible sexual signal, due to its relationships with other variables such as age, body size, antler development, volatile compounds, or the competitive environment. The analysis of fur pigmentation at the ventral patch suggests that this might also visually indicate the male intrinsic predisposition to take part in mating competition. Results To assess the possible role of this trait as a communicative signal related to mate competition, we used red deer behavioral observations during the rut in Doñana National Park (Spain) to examine the link between the degree of expression of the dark ventral patch and the rutting activity (assessed from both intra-and-inter-sexual behaviors). Consistent with our predictions, we found in a field study that males with large dark patches showed a higher frequency of rutting behaviors (mainly roaring and flehmen), more interactions with females, and attained larger harem sizes. Conclusions The dark ventral patch was a better predictor of male behavior than antler tines or territory holding, thus standing as a short-term indicator of male willingness to invest in mating competition.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Martin L. Pall

Abstract Millimeter wave (MM-wave) electromagnetic fields (EMFs) are predicted to not produce penetrating effects in the body. The electric but not magnetic part of MM-EMFs are almost completely absorbed within the outer 1 mm of the body. Rodents are reported to have penetrating MM-wave impacts on the brain, the myocardium, liver, kidney and bone marrow. MM-waves produce electromagnetic sensitivity-like changes in rodent, frog and skate tissues. In humans, MM-waves have penetrating effects including impacts on the brain, producing EEG changes and other neurological/neuropsychiatric changes, increases in apparent electromagnetic hypersensitivity and produce changes on ulcers and cardiac activity. This review focuses on several issues required to understand penetrating effects of MM-waves and microwaves: 1. Electronically generated EMFs are coherent, producing much higher electrical and magnetic forces then do natural incoherent EMFs. 2. The fixed relationship between electrical and magnetic fields found in EMFs in a vacuum or highly permeable medium such as air, predicted by Maxwell’s equations, breaks down in other materials. Specifically, MM-wave electrical fields are almost completely absorbed in the outer 1 mm of the body due to the high dielectric constant of biological aqueous phases. However, the magnetic fields are very highly penetrating. 3. Time-varying magnetic fields have central roles in producing highly penetrating effects. The primary mechanism of EMF action is voltage-gated calcium channel (VGCC) activation with the EMFs acting via their forces on the voltage sensor, rather than by depolarization of the plasma membrane. Two distinct mechanisms, an indirect and a direct mechanism, are consistent with and predicted by the physics, to explain penetrating MM-wave VGCC activation via the voltage sensor. Time-varying coherent magnetic fields, as predicted by the Maxwell–Faraday version of Faraday’s law of induction, can put forces on ions dissolved in aqueous phases deep within the body, regenerating coherent electric fields which activate the VGCC voltage sensor. In addition, time-varying magnetic fields can directly put forces on the 20 charges in the VGCC voltage sensor. There are three very important findings here which are rarely recognized in the EMF scientific literature: coherence of electronically generated EMFs; the key role of time-varying magnetic fields in generating highly penetrating effects; the key role of both modulating and pure EMF pulses in greatly increasing very short term high level time-variation of magnetic and electric fields. It is probable that genuine safety guidelines must keep nanosecond timescale-variation of coherent electric and magnetic fields below some maximum level in order to produce genuine safety. These findings have important implications with regard to 5G radiation.


Semiotica ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Michael Ranta

Abstract The theoretical debate on the nature of narrative has been mainly concerned with literary narratives, whereas forms of non-literary and especially pictorial narrativity have been somewhat neglected. In this paper, however, I shall discuss narrativity specifically with regard to pictorial objects in order to clarify how pictorial storytelling may be based on the activation of mentally stored action and scene schemas. Approaches from cognitive psychology, such as the work of Schank, Roger C. & Robert P. Abelson. 1977. Scripts, plans, goals and understanding. Hillsdale, NJ: Lawrence Erlbaum; Mandler, Jean Matter. 1984. Stories, scripts, and scenes: Aspects of schema theory. London/Hillsdale, NJ: Lawrence Erlbaum; Schank, Roger C. 1995. Tell me a story: Narrative and intelligence. Evanston, IL: Northwestern University Press, suggest that cognition crucially depends on the storage and retrieval of action scripts or schemata, that is, narrative structures, which may occur at various levels of abstraction. These schemas incorporate generalized knowledge about event sequences, such as the order in which specific events will take place; causal, enabling, or conventionalized relations between these events, and what kind of events occur in certain action sequences. There also are scene schemas that are characterized by spatial rather than temporal relations. Further kinds of schemas seem also to play a decisive role. Drawing upon considerations from schema and script theory, I will focus on some concrete examples of pictorial narration, more specifically depictions of the Annunciation of the Virgin Mary, where narrative schema structures become involved and, indeed, the comprehensibility of the pictures as such presuppose mental script representations.


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