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The Optical Variability Properties of TeV Blazars

Research in Astronomy and Astrophysics 2024年第9期24卷 66-75页

作者： Zi-An Su Wen-Xin Yang Xiang-Tao Zeng le-jian ou Ze-Lin Li jiang-He Yang Jun-Hui Fan Department of Physics School of Physics and ElectronicsHunan Normal UniversityChangsha 410081China Center for Astrophysics Guangzhou UniversityGuangzhou 510006China Greater Bay Brand Center of the National Astronomical Data Center Guangzhou 510006China Astronomy Science and Technology Research Laboratory of Department of Education of Guangdong Province Guangzhou 510006China College of Microelectronics Feicuihu Campus of Hefei University of TechnologyHefei 230601China College of Mathematics and Physics Science Hunan University of Arts and ScienceChangde 415000China

Variability is one of the typical observational properties of blazars and the spectral changes are usually associated with variability,although this kind of association is unclear *** this work,we used data from the Steward Observatory blazar monitoring program to investigate the optical variability properties including the short-term timescale,the brightness-dependent spectral property,the correlation between the the brightness variation and the polarization,and then estimate the Doppler factors based on the obtained short timescale to study the polarization property for a sample of 20 TeV *** analyses arrive at the following results:(1)The largest variation amplitude in R-band,ΔR_(M),covers a range from ΔR_(M)=0.29 mag(1ES 2344+514)to ΔR_(M)=4.66 mag(3C 279).(2)Intra-day variability was found from five sources with timescales from 0.14 day for S50716+714 to 0.98 day for PKS *** sources show spectra that are bluer when they become brighter,suggesting a common bluer-when-brighter property.(3)The plot of the polarization versus estimated Doppler factor is consistent with the Doppler factor dependent formula of polarization.(4)The largest polarization is correlated with the largest optical variation,suggesting that the high polarization and high amplitude variation are both the indicator of beaming effect.

关键词： galaxies:active galaxies:jets radiation mechanisms:non-thermal

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Quantum transport in topological insulator hybrid structures-A combination of topological insulator and superconductor

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Science China(Physics,Mechanics & Astronomy) 2012年第12期55卷 2226-2236页

作者： ou YongXi SINGH Meenakshi WANG jian International Center for Quantum Materials School of PhysicsPeking UniversityBeijing 100871China The Center for Nanoscale Science and Department of Physics The Pennsylvania State UniversityUniversity ParkPennsylvania 16802-6300USA

In this paper,a brief review of the history of topological insulators is *** that,electronic transport experiments in topological insulator-superconductor hybrid structures,including experimental methods,physical properties and seemingly contradictory observations are ***,some new topological insulator hybrid structures are proposed.

关键词： topological insulator transport property superconductor hybrid structure surface state

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Simulation of turbulent combustion in DLR Scramjet

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第7期8卷 1053-1058页

作者： Zou jian-feng ZHENG Yao LIU ou-zi School of Aeronautics and Astronautics Zhejiang University Hangzhou 310027 China

Turbulent combustion in a DLR (German Aerospace Center) Scramjet engine was simulated using the newly-proposed Partially Resolved Numerical Simulation (PRNS) procedure. The PRNS procedure uses temporal filtering to define large-scale turbulence, and the model developed to account for unresolved scales is grid independent. No problem about inner commutation error and inconsistencies will arise from the PRNS, while such issues are of concern in traditional Large Eddy Simulation (leS) methods. The mean results have good agreement with the experiment data and the flow structures with small scales are well resolved.

关键词： Scramjet Turbulent combustion Unstructured grid Finite volume method

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Accelerating the HS-type Richardson Iteration Method with Anderson Mixing

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Acta Mathematica Sinica,English Series 2022年第11期38卷 2069-2089页

作者： Zhi Zhi LI Huai ZHANG le ou-YANG Key Laboratory of Computational Geodynamics University of Chinese Academy of SciencesBeijing 100049P.R.China Guangdong Key Laboratory of Intelligent Information Processing Shenzhen Key Laboratory of Media Securityand Guangdong Laboratory of Artificial Intelligence and Digital Economy(SZ)College of Electronics and Information EngineeringShenzhen UniversityShenzhen 518060P.R.China

The Accelerated Hermitian/skew-Hermitian type Richardson(AHSR)iteration methods are presented for solving non-Hermitian positive definite linear systems with three schemes,by using Anderson *** upper bounds of spectral radii of iteration matrices are studied,and then the convergence theories of the AHSR iteration methods are ***,the optimal iteration parameters are provided,which can be computed *** addition,the application to the model convection-diffusion equation is depicted and numerical experiments are conducted to exhibit the effectiveness and confirm the theoretical analysis of the AHSR iteration methods.

关键词： Anderson mixing Hermitian/skew-Hermitian splitting the Richardson iteration convergence analyses optimal parameters the model convection-diffusion equation

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Excitation Spectrum of Three Dressed Bose-Einstein Condensates

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Chinese Physics letters 2000年第9期17卷 628-630页

作者： ou-YANG Zhong-Wen KUANG le-Man Department of Physics Hu’nan Normal UniversityChangsha 410081

We study quantum dynamics of three dressed Bose-Einstein condensates in a high-Q *** quasiparticle excitation spectrum of this system is found *** stability of the quasiparticle excitation is *** is shown that there e... 详细信息

关键词： spectrum. cavity. excitation

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Non-equilibrium turbulent phenomena in transitional flat plate boundary-layer flows

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Applied Mathematics and Mechanics(English Edition) 2021年第4期42卷 567-582页

作者： Feng LIU le FANG jian FANG School of Energy and Power Engineering North University of ChinaTaiyuan 030051China Laboratory of Mathematics and Physics Ecole Centrale de P′ekinBeihang UniversityBeijing 100191China Scientific Computing Department STFC Daresbury LaboratoryWarrington WA44ADU.K.

Many recent laboratory experiments and numerical simulations support a non-equilibrium dissipation scaling in decaying turbulence before it reaches an equilibrium *** analyzing a direct numerical simulation(DNS)database of a transitional boundary-layer flow,we show that the transition region and the non-equilibrium turbulence region,which are located in different streamwise zones,present different non-equilibrium ***,in the wall-normal direction,the viscous sublayer,log layer,and outer layer show different non-equilibrium phenomena which differ from those in grid-generated turbulence and transitional channel *** findings are expected to shed light on the modelling of various types of non-equilibrium turbulent flows.

关键词： non-equilibrium turbulence flat plate boundary layer turbulence model

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Steady-State Creep Behavior of Super304H Austenitic Steel at Elevated Temperatures

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Acta Metallurgica Sinica(English letters) 2015年第11期28卷 1336-1343页

作者： Ping ou Long Li Xing-Fei Xie jian Sun Shanghai Key Laboratory of Advanced High-Temperature Materials and Precision Forming School of Materials Science and EngineeringShanghai Jiaotong University School of Materials Science and Engineering Jiangxi University of Science and Technology

Creep behavior of Super304H austenitic steel has been investigated at elevated temperatures of 923-973 K and at applied stress of 190-210 MPa. The results show that the apparent stress exponent and activation energy in the creep deformation range from 16.2 to 27.4 and from 602.1 to 769.3 kJ/mol at different temperatures, respectively. These high values imply the presence of a threshold stress due to an interaction between the dislocations and Cu-rich precipitates during creep deformation. The creep mechanism is associated with the dislocation climbing governed by the matrix lattice diffusion. The origin of the threshold stress is mainly attributed to the coherency strain induced in the matrix by Cu-rich precipitates. The theoretically estimated threshold stresses from Cu-rich precipitates agree reasonably with the experi- mental results.

关键词： Super304H steel Cu-rich precipitate Creep Threshold stress

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Re-examination of statistical relationships between dietary fats and other risk factors,and cardiovascular disease,based on two crucial datasets

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Quantitative Biology 2024年第1期12卷 117-127页

作者： Jiarui ou le Zhang Xiaoli Ru College of Computer Science Sichuan UniversityChengduChina Department of Gynecology and Obstetrics Beijing Chao-Yang HospitalCapital Medical UniversityBeijingChina

Cardiovascular disease(CVD)is the major cause of death in many regions around the world,and several of its risk factors might be linked to *** improve public health and the understanding of this topic,we look at the recent Minnesota Coronary Experiment(MCE)analysis that used t-test and Cox model to evaluate CVD ***,these parametric methods might suffer from three problems:small sample size,right-censored bias,and lack of long-term *** overcome the first of these challenges,we utilize a nonparametric permutation test to examine the relationship between dietary fats and serum total *** address the second problem,we use a resampling-based rank test to examine whether the serum total cholesterol level affects CVD *** the third issue,we use some extra-Framingham Heart Study(FHS)data with an A/B test to look for meta-relationship between diets,risk factors,and CVD *** show that,firstly,the link between low saturated fat diets and reduction in serum total cholesterol is ***,reducing serum total cholesterol does not robustly have an impact on CVD hazards in the diet ***,the A/B test result suggests a more complicated relationship regarding abnormal diastolic blood pressure ranges caused by diets and how these might affect the associative link between the cholesterol level and heart disease *** study not only helps us to deeply analyze the MCE data but also,in combination with the long-term FHS data,reveals possible complex relationships behind diets,risk factors,and heart disease.

关键词： A/B test bioinformatics cardiovascular disease nonparametric statistics

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EPIC 202843107:a close eclipsing binary containing a δ Scuti variable

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Research in Astronomy and Astrophysics 2019年第8期19卷 63-68页

作者： jian-Wen ou Ming Yang Ji-Lin Zhou School of Astronomy and Space Science & Key Laboratory of Modern Astronomy and Astrophysics in Ministry of Education Nanjing University

This paper reports on the discovery that an eclipsing binary system, EPIC 202843107, has aδ Scuti variable component. The phased light curve from the Kepler space telescope presents a detached configuration. The binary modeling indicates that the two component stars have almost the same radius and may have experienced orbital circularization. Frequency analyses are performed for the residual light curve after subtracting the binary variations. The frequency spectrum reveals that one component star is a δ Scuti variable. A large frequency separation is cross-identified with the corresponding histogram, the Fourier transform and the echelle diagram method. The mean density of the δ Scuti component is estimated to be 0.09 g cm-3 based on the large separation and density relation. Systems like EPIC 202843107 are helpful to study the stellar evolution and physical state of binary stars.

关键词： binaries:eclipsing-stars:individual:EPIC 202843107 stars:variables:δ Scuti stars:oscillations

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Preparation and characterization of polystyrene-based monolith with ordered macroporous structure

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Chinese Chemical letters 2012年第4期23卷 474-477页

作者： Quan Zhou Wu jian Feng He Ji Ming ou College of Chinese Materia Medica Guangzhou University of Chinese MedicineGuangzhou 510006China

In this paper,polystyrene-based monoliths with highly ordered macroporous structure were synthesized by using SiO_2 colloidal crystal as *** observation shows that the macropores are highly ordered and are interconnected by small *** BET surface area of PS monolith is about 36.17 m^2/*** polymer monoliths can resist 5 MPa pressure,showing high mechanical and compressive strength.

关键词： Monolith Polystyrene Polymer Ordered macropore

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