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Non-Gaussian statistics of partially coherent light in atmospheric turbulence

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Chinese Physics B 2020年第6期29卷 54-59页

作者： Hao Ni Chunhao Liang Fei Wang Yahong Chen sergey APonomarenko Yangjian Cai School of Physical Science and Technology&Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow UniversitySuzhou 215006China Shandong Provincial Engineering and Technical Center of Light Manipulation&Shandong Provincial Key Laboratory of Optics and Photonic Device School of Physics and ElectronicsShandong Normal UniversityJinan 250014China Department of Electrical and Computer Engineering Dalhousie UniversityHalifaxNova ScotiaB3J 2X4Canada Department of Physics and Atmospheric Science Dalhousie UniversityHalifaxNova ScotiaB3H 4R2Canada

We derive theoretically and verify experimentally a concise general expression for the normalized intensity correlations(IC)of partially coherent light in a weak atmospheric turbulence in the fast detector measurement *** derived relation reveals that the medium turbulence acts,in general,as an additional noise source enhancing the IC of partially coherent *** maximum of the beam IC is,in general,enhanced,causing the fields to exhibit super-Gaussian *** the other hand,the relation indicates that turbulence-induced noise is negligible for sufficiently low coherence light,which reveals the condition for the turbulence-free correlation imaging.

关键词： partially coherent beam atmospheric turbulence intensity correlation

Heart Rate Extraction from Vowel Speech Signals

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Journal of Computer Science & Technology 2012年第6期27卷 1243-1251页

作者： Abdelwadood Mesleh Dmitriy Skopin sergey Baglikov Anas Quteishat Computer Engineering Department Faculty of Engineering TechnologyAl-Balqa' Applied UniversityAmmanJordan Help MediCom Group KurskRussia

This paper presents a novel non-contact heart rate extraction method from vowel speech signals. The proposed method is based on modeling the relationship between speech production of vowel speech signals and heart activities for humans where it is observed that the moment of heart beat causes a short increment （evolution） of vowel speech formants. The short-time Fourier transform （STFT） is used to detect the formant maximum peaks so as to accurately estimate the heart rate. Compared with traditional contact pulse oximeter, the average accuracy of the proposed non-contact heart rate extraction method exceeds 95%. The proposed non-contact heart rate extraction method is expected to play an important role in modern medical applications.

关键词： electrocardiogram feature extraction heart rate short-tlme Fourier transform vowel speech signal

Strain control of layer-resolved negative capacitance in superlattices

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npj Computational Materials 2020年第1期6卷 127-130页

作者： Raymond Walter sergey Prosandeev Charles Paillard L.Bellaiche Department of Physics and Institute for Nanoscience and Engineering University of ArkansasFayettevilleAR 72701USA Department of Mathematical Sciences University of ArkansasFayettevilleAR 72701USA Identity Engineering Kinesso LLCConwayAR 72032USA Institute of Physics and Physics Department of Southern Federal University Rostov-na-Donu 344090Russia Laboratoire Structures Propriétés et Modélisation des SolidesCentraleSupélecUMR CNRS 8580UniversitéParis-Saclay91190 Gif-sur-YvetteFrance

Negative capacitance in BaTiO_(3)/SrTiO_(3) superlattices is investigated by Monte Carlo simulations in an atomistic effective Hamiltonian model,using fluctuation formulas for responses to the local macroscopic field that incorporates depolarizing *** show that epitaxial strain can tune the negative capacitance of the BaTiO_(3) ferroelectric layer and the overall capacitance of the *** addition,we predict and explain an original switching of the negative capacitance from the BaTiO3 layer to the SrTiO_(3) layer at low temperatures for intermediate strains.

关键词： capacitance layer resolved

Excessive Use of WeChat:A Study from the Stress Perspective

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Excessive Use of WeChat:A Study from the Stress Perspective

作者： Yurkov sergey 苏州大学

学位级别：硕士

WeChat has become the irreplaceable communication *** is a utility that greatly facilitates and augments communication over distances,includes many features and ways to gratify individuals’ needs for entertainment and *** any information system is a double-edged *** may not be aware of the fact that when such technology becomes the way of life,it is often overused,which can lead to substantial negative health outcomes-from overload,to stress,and even *** is especially acute for students who manage their academic and work lives and have no choice but to use WeChat for *** study contributes useful practical knowledge to the existing pool of research on stress and health communication by drawing attention to problematic use of WeChat in the educational setting identifying stress-creators and their outcomes and ways to mitigate possible negative *** from 174 respondents collected at a major university in China were analyzed,results and possible suggestions for students and faculty,as well as app developers are *** study theorizes overuse and three major factors of overload that result from it,as well as reasons for overuse,their psychological and behavioral outcomes in form of social network fatigue and dissatisfaction,respectively,and coping *** resulting structural model is validated and hypotheses are *** variables gender and number of friends as moderators of effects are also examined.

关键词： WeChat overuse life stress SNS overload SNS fatigue SNSdissatisfaction uses and gratifications stress andcoping

Analysis of Finite Difference Approximations of an Optimal Control Problem in Economics

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Advances in Applied Mathematics and Mechanics 2019年第6期11卷 1358-1375页

作者： Alexander Lapin Shuhua Zhang sergey Lapin Na Yan Institute of Computational Mathematics and Information Technologies Kazan Federal UniversityKazan 420008Russia Coordinated Innovation Center for Computable Modeling in Management Science Tianjin University of Finance and EconomicsTianjin 300222China Department of Mathematics and Statistics Washington State UniversityPullmanWA 99163USA Business School Nankai UniversityTianjin 300071China

We consider an optimal control problem which serves as a mathematical model for several problems in economics and *** problem is the minimization of a continuous constrained functional governed by a linear parabolic diffusion-advection equation controlled in a coefficient in advection *** additional constraint is non-negativity of a solution of state *** construct and analyze several mesh schemes approximating the formulated problem using finite difference methods in space and in *** these approximations keep the positivity of the solutions to mesh state problem,either unconditionally or under some additional constraints to mesh *** allows us to remove corresponding constraint from the formulation of the discrete problem to simplify its *** on theoretical estimates and numerical results,we draw conclusions about the quality of the proposed mesh schemes.

关键词： Mean field game optimal control problem parabolic diffusion-advection equation finite difference methods

Pulsating magneto-dipole radiation of a quaking neutron star powered by energy of Alfvn seismic vibrations

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Research in Astronomy and Astrophysics 2011年第9期11卷 1085-1092页

作者： sergey Bastrukov Jun-Wei Yu Ren-Xin Xu Irina Molodtsova State Key Laboratory of Nuclear Physics and Technology School of Physics Peking University Beijing 100871 China Joint Institute for Nuclear Research 141980 Dubna Russia

We compute the characteristic parameters of the magneto-dipole radiation of a neutron star undergoing torsional seismic vibrations under the action of Lorentz restoring force about an axis of a dipolar magnetic field experiencing decay. After a brief outline of the general theoretical background of the model of a vibration-powered neutron star, we present numerical estimates of basic vibration and radiation characteristics, such as frequency, lifetime and luminosity, and investigate their time dependence on magnetic field decay. The presented analysis suggests that a gradual decrease in frequencies of pulsating high-energy emission detected from a handful of currently monitored AXP/SGR-like X-ray sources can be explained as being produced by the vibration-powered magneto-dipole radiation of quaking magnetars.

关键词： neutron stars -- torsion Alfv6n vibrations -- vibration powered radiation -- magnetic field decay -- magnetars

Investigation of radio pulsar emission features using power spectra

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Research in Astronomy and Astrophysics 2018年第8期18卷 63-70页

作者： Valery M.Malofeev sergey A.Tyul'bashev EN.Lebedev Physical Institute of the Russian Academy of Sciences V.V.Vitkevich Pushchino Radio Astronomy ObservatoryPRAO ASC FIANPushchinoRussia

Since 2013, round-the-clock monitoring of the sky has been carried out simultaneously in 96 beams using a high-sensitivity radio telescope called the Large Phased Array （LPA） at the frequency 110.25 MHz. These observations are made under the program of interplanetary plasma investigation. The same data are used to search for pulsars by means of power spectra. To increase the sensitivity of the pulsar search, 500-600 power spectra corresponding to different days of observations are summed. In the integrated spectra of known pulsars, besides expected improvement in signal-to-noise （S/N） ratio for the frequency harmonics, some features are explored in this paper. We present the 27 strongest pulsars which are in a field with declination 21° - 42°. The observable details in the integrated power spectra are connected with the presence of pulsar periods of the second （P2） and third （P3） class, which have been identified. Empirical relations for calculating these periods are obtained. The value P2 is estimated for 26 pulsars, and for 15 sources it is made for the first time. The value P3 is estimated for 13 pulsars, among them these values are given for five sources for the first time.

关键词： pulsars general - pulsars

K^+ retention in leaf mesophyll, an overlooked component of salinity tolerance mechanism:A case study for barley

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Journal of Integrative Plant Biology 2015年第2期57卷 171-185页

作者： Honghong Wu Min Zhu Lana Shabala Meixue Zhou sergey Shabala School of Land and Food University of Tasmania

Plant salinity tolerance is a physiologically complex trait, with numerous mechanisms contributing to it. In this work, we show that the ability of leaf mesophyll to retain K＋ represents an important and essentially overlooked component of a salinity tolerance mechanism. The strong positive correlation between mesophyll K＋ retention ability under saline conditions （quantified by the magnitude of NaCl-induced K＋ efflux from mesophyll） and the overall salinity tolerance （relative fresh weight and/or survival or damage under salinity stress） was found while screening 46 barley （Hordeum vulgare L.） genotypes contrasting in their salinity tolerance. Genotypes with intrinsically higher leaf K＋ content under control conditions were found to possess better K＋ retention ability under salinity and, hence, overall higher tolerance. Contrary to previous reports for barley roots, K＋ retention in mesophyll was not associated with an increased H＋-pumping in tolerant varieties but instead correlated negatively with this trait. These findings are explained by the fact that increased H＋ extrusion may be needed to charge balance the activity and provide the driving force for the high affinity HAK/KUP K＋ transporters required to restore cytosolic K＋ homeostasis in salt-sensitive genotypes.

关键词： Cytosolic K+ homeostasis ion flux membrane potential membrane transport tissue tolerance

Dynamic magnetic hysteresis in a liquid suspension of acicular maghemite particles

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Particuology 2009年第6期7卷 451-458页

作者： Bronislav E.Kashevsky sergey B.Kashevsky Igor V.Prokhorov A.V.Luikov Heat and Mass Transfer Institute Belarus Academy of SciencesP.Brovka str.15Minsk 220072Belarus

This paper presents theoretical and experimental studies on the magnetodynamics and energy absorption in a dilute suspension of small ferromagnetic particles with magnetic hysteresis and mechanical mobility in an AC magnetic field. Experiments with 0.1% suspensions of acicular particles of gamma ferric oxide in solid and liquid matrices, subjected to a 430 Hz magnetic field with an intensity of up to 1200 Oe, revealed important role of particle mobility. The main qualitative and quantitative features of the phenomenon are in agreement with a model of joint magneto-mechanical dynamics of particles with a chain-of-spheres mode of incoherent magnetic reversal.

关键词： High-coercive magnetic particles Magnetic suspensions Dynamic magnetic hysteresis