Electron transport and optical properties of shallow GaAs/InGaAs/GaAs quantum wells with a thin central AlAs barrier

Shallow GaAs/InGaAs/GaAs quantum well structures with and without a three monolayer thick AlAs central barrier have been investigated for different well widths and Si doping levels. The transport parameters are determined by resistivity measurements in the temperature range 4-300 K and magnetotransport in magnetic fields up to 12 T. The (subband) carrier concentrations and mobilities are extracted from the Hall data and Shubnikov-de Haas oscillations. We find that the transport parameters are strongly affected by the insertion of the AlAs central barrier. Photoluminescence spectra, measured at 77 K, show an increase of the transition energies upon insertion of the barrier. The transport and optical data are analyzed with help of self-consistent calculations of the subband structure and envelope wave functions. Insertion of the AlAs central barrier changes the spatial distribution of the electron wave functions and leads to the formation of hybrid states, i.e. states which extend over the InGaAs and the delta-doped layer quantum wells.Comment: 14 pages, pdf fil

Kronecker's Double Series and Exact Asymptotic Expansion for Free Models of Statistical Mechanics on Torus

For the free models of statistical mechanics on torus, exact asymptotic expansions of the free energy, the internal energy and the specific heat in the vicinity of the critical point are found. It is shown that there is direct relation between the terms of the expansion and the Kronecker's double series. The latter can be expressed in terms of the elliptic theta-functions in all orders of the asymptotic expansion.Comment: REVTeX, 22 pages, this is expanded version which includes exact asymptotic expansions of the free energy, the internal energy and the specific hea

Multifractality in Time Series

We apply the concepts of multifractal physics to financial time series in order to characterize the onset of crash for the Standard & Poor's 500 stock index x(t). It is found that within the framework of multifractality, the "analogous" specific heat of the S&P500 discrete price index displays a shoulder to the right of the main peak for low values of time lags. On decreasing T, the presence of the shoulder is a consequence of the peaked, temporal x(t+T)-x(t) fluctuations in this regime. For large time lags (T>80), we have found that C_{q} displays typical features of a classical phase transition at a critical point. An example of such dynamic phase transition in a simple economic model system, based on a mapping with multifractality phenomena in random multiplicative processes, is also presented by applying former results obtained with a continuous probability theory for describing scaling measures.Comment: 22 pages, Revtex, 4 ps figures - To appear J. Phys. A (2000

Investigation of the Influence of the Instability of the Operation of the Transmitting Laser Channel, Pointing Errors, Atmospheric Turbulence on the Characteristics of Its Radiation in the Far Zone

На основе методов теории распространения электромагнитных волн оптического диапазона в турбулентной атмосфере, математической статистики и функционального преобразования случайных величин проведена оценка плотности распределения интенсивности флуктуирующего излучения, создаваемой передающим каналом лазера в дальней зоне. Применительно к пороговым интенсивностям излучения, учитывающим различные режимы генерации передающего лазерного канала определена вероятность достижения заданного уровня интенсивности излучения в области оптико-электронного средства. С использованием данного показателя эффективности проведено исследование влияния нестабильности работы передающего лазерного канала, ошибок наведения, турбулентности атмосферы на характеристики его излучения в плоскости апертуры формирующей оптики оптико-электронного средства. Показано, что прохождение лазерного излучения через случайно-неоднородную среду сопровождается возникновением ошибок наведения лазерного луча и его расширением, оказывающим существенное влияние на достижение заданного уровня интенсивности излучения в области оптико-электронного средства. Повышение показателя эффективности возможно за счет выбора оптимального угла расходимости лазерного излучения передающего канала, учитывающего флуктуации показателя диэлектрической проницаемости и преломления атмосферыBased on the methods of the theory of propagation of electromagnetic waves in the optical range in a turbulent atmosphere, mathematical statistics, and functional transformation of random variables, an estimate is made of the distribution density of the intensity of fluctuating radiation created by a laser transmitting channel in the far zone. With regard to the threshold radiation intensities, which take into account the different modes of generation of the transmitting laser channel, the probability of reaching a given level of radiation intensity in the region of the optoelectronic means is determined. Using this efficiency indicator, a study was made of the influence of the instability of the operation of the transmitting laser channel, pointing errors, and atmospheric turbulence on the characteristics of its radiation in the aperture plane of the forming optics of the optoelectronic means. It is shown that the passage of laser radiation through a randomly inhomogeneous medium is accompanied by errors in pointing the laser beam and its expansion, which has a significant effect on achieving a given level of radiation intensity in the region of the optoelectronic means. An increase in the efficiency index is possible by choosing the optimal angle of divergence of the laser radiation of the transmitting channel, which takes into account fluctuations in the dielectric constant and refractive index of the atmospher

Decoherence produces coherent states: an explicit proof for harmonic chains

We study the behavior of infinite systems of coupled harmonic oscillators as t->infinity, and generalize the Central Limit Theorem (CLT) to show that their reduced Wigner distributions become Gaussian under quite general conditions. This shows that generalized coherent states tend to be produced naturally. A sufficient condition for this to happen is shown to be that the spectral function is analytic and nonlinear. For a rectangular lattice of coupled oscillators, the nonlinearity requirement means that waves must be dispersive, so that localized wave-packets become suppressed. Virtually all harmonic heat-bath models in the literature satisfy this constraint, and we have good reason to believe that coherent states and their generalizations are not merely a useful analytical tool, but that nature is indeed full of them. Standard proofs of the CLT rely heavily on the fact that probability densities are non-negative. Although the CLT generally fails if the probability densities are allowed to take negative values, we show that a CLT does indeed hold for a special class of such functions. We find that, intriguingly, nature has arranged things so that all Wigner functions belong to this class.Comment: Final published version. 17 pages, Plain TeX, no figures. Online at http://astro.berkeley.edu/~max/gaussians.html (faster from the US), from http://www.mpa-garching.mpg.de/~max/gaussians.html (faster from Europe) or from [email protected]

МЕХАНИЗМ СТАБИЛЬНОСТИ ТОРФЯНЫХ БИТУМОВ

It has been established that the reason for stability of peat bitumes during metamorphism process is the presence of “quasipolyconjugation” systems caused by synergistic effect of the interaction of individual aromatic rings and hydrogen bondings functional groups.Установлено, что стабильность торфяных битумов в процессе метаморфизма обязана наличию систем «квазипо­ лисопряжения», обусловленных синергическим эффектом взаимодействия одиночных ароматических колец и водо­ родных связей функциональных групп

Новые аспекты решения проблемы индикации и измерения геопатогенных и аномальных зон = New aspects of solving the problem indication and measurements and geopathogenic anomalous zones

Klimentov V. V., Prohorov G. V., Gozhenko S. A., Zukow W. Новые аспекты решения проблемы  индикации и измерения геопатогенных и аномальных зон = New aspects of solving the problem indication and measurements and geopathogenic anomalous zones. Journal of Education, Health and Sport. 2015;5(4):109-116. ISSN 2391-8306. DOI: 10.5281/zenodo.16658 http://ojs.ukw.edu.pl/index.php/johs/article/view/2015%3B5%284%29%3A109-116 https://pbn.nauka.gov.pl/works/553461 http://dx.doi.org/10.5281/zenodo.16658 Formerly Journal of Health Sciences. ISSN 1429-9623 / 2300-665X. Archives 2011 – 2014 http://journal.rsw.edu.pl/index.php/JHS/issue/archive   Deklaracja. Specyfika i zawartość merytoryczna czasopisma nie ulega zmianie. Zgodnie z informacją MNiSW z dnia 2 czerwca 2014 r., że w roku 2014 nie będzie przeprowadzana ocena czasopism naukowych; czasopismo o zmienionym tytule otrzymuje tyle samo punktów co na wykazie czasopism naukowych z dnia 31 grudnia 2014 r. The journal has had 5 points in Ministry of Science and Higher Education of Poland parametric evaluation. Part B item 1089. (31.12.2014). © The Author (s) 2015; This article is published with open access at Licensee Open Journal Systems of Kazimierz Wielki University in Bydgoszcz, Poland and Radom University in Radom, Poland Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited. This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited. The authors declare that there is no conflict of interests regarding the publication of this paper. Received: 20.01.2014. Revised 27.03.2015. Accepted: 27.03.2015.   НОВЫЕ АСПЕКТЫ РЕШЕНИЯ ПРОБЛЕМЫ  ИНДИКАЦИИ И ИЗМЕРЕНИЯ ГЕОПАТОГЕННЫХ И АНОМАЛЬНЫХ ЗОН NEW ASPECTS OF SOLVING THE PROBLEM INDICATION AND MEASUREMENTS AND Geopathogenic anomalous zones   В. В. Климентов, Г. В. Прохоров, С. А. Гоженко, В. Жуков V. V. Klimentov, G. V. Prohorov, S. A. Gozhenko, W. Zukow   Научный парк «Профилактическая медицина и охрана труда – новейшие системы и технологии», Одесса Черновицкий национальный университет им. Ю. Федьковича Украинский НИИ медицины транспорта, Одесса Uniwersytet Kazimierza Wielkiego, Bydgoszcz   Science park «Preventive Medicine and Health - The latest systems and technologies ", Odessa Chernivtsi National University Yu. Fedkovicha Ukrainian scientific-research institute of transport medicine, Odessa Kazimierz Wielki University, Bydgoszcz   Abstract   The article deals with the creation of prerequisites for hardware and software system for the study of abnormal and geopathic zones. Analyzes the currently used instruments for detection and measurement of parameters and characteristics of pathogenic influences in anomalous zones. The author's methodology that combines the method of multi-channel measurements of physical quantities with mathematical methods of statistical analysis, since the methods and instruments used for this purpose now, in principle, not reliably determine their qualitative and quantitative parameters of such zones. The proposed approach to the problem is promising interdisciplinary study of natural phenomena.   Keywords: appliance, anomalous zones, geopathic zones, Schumann resonances, electromagnetic field, software and hardware, micropulsations, stochastic resonance.   Реферат   В статье рассматриваются предпосылки создания программно-аппаратного комплекса для исследования аномальных и геопатогенных зон. Анализируются   применяемые  в настоящее время приборы для индикации и измерения параметров и характеристик патогенных воздействий в аномальных зонах. Предлагается авторская  методология,   позволяющая объединить метод многоканальных измерений физических величин с математическими методами статистического анализа, поскольку методики и приборы,  используемые для этой цели в настоящее время, в принципе не позволяют достоверно определять их качественные и количественные параметры таких зон. Предлагаемый  подход к решению проблемы является перспективным направлением междисциплинарного исследования природных феноменов.   Ключевые слова: прибор, аномальные зоны, геопатогенные зоны, резонансы Шумана, электромагнитное поле, программно-аппаратный комплекс, микропульсации, стохастический резонанс