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Gamma-ray bursts in the Swift-Fermi era:Confronting data with theory

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science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 14-23页

作者： LIANG EnWei physical science & {2. College,guangxi university,nanning 530004,china guangxi Univ Phys Sci & Technol Coll Nanning 530004 Peoples R China

With the prompt slewing capability of the X-ray and UV-optical telescopes onboard the Swift mission and with the gamma-ray large area telescope onboard the Fermi mission,gamma-ray bursts(GRBs) are now accessible in a full time window and in all electromagnetic wavelengths for the *** observational breakthroughs have been made in recent years.I present here a brief review of some observational breakthroughs with the two missions,focusing on how these breakthroughs have revolutionized our understanding of the nature of this phenomenon and puzzles as well as challenges of confronting the conventional models with data.

关键词： radiation mechanism gamma rays bursts high energy phenomenon

Effect of surface nanocrystallization on the corrosion behavior of Zircaloy-4

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science china(Technological sciences) 2009年第8期52卷 2227-2231页

作者： ZHU YuTao1,2.& ZHANG XiYan1,2.3 1 College of Materials science and Engineering, Chongqing university, Chongqing 400045,{2. 2.National Engineering Research Center for Magnesium Alloys, Chongqing university, Chongqing 400044,{2. 3 school of physical science and Engineering technology, guangxi university, nanning 530004,{2. 1. College of Materials science and Engineering Chongqing University Chongqing 400045 China 2. National Engineering Research Center for Magnesium Alloys Chongqing University Chongqing 400044 China 3. school of physical {2. and Engineering technology Guangxi University Nanning 530004 China

The contrastive corrosion experiments between surface nanocrystallined Zircaloy-4 and coarse-grained Zircaloy-4 under the condition of 673 K/10.3 MPa in pure water are carried out, and the microstructure of oxide films has been studied. The results indicate that the growth rate of oxide films formed on the nanocrystalline Zircaloy-4 is lower than that of oxide films formed on the coarse-grained Zircaloy-4. Simultaneously, the oxide/metal interface of the former is more regular and glossy than that of the latter. For nanocrystalline Zircaloy-4, the low oxygen diffusion rate through the oxide/metal interface can hinder the reaction of oxygen ion with metal ion. Furthermore, more tetragonal ZrO2.are observed in the oxide films, which can delay the martensite phase transition from tetragonal to monoclinic phase in oxide films.

关键词： nanocrystalline Zircaloy oxide film microstructure

The flux-E_p relation within GRB0602.8 in comparison with typical GRB pulses

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science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 78-81页

作者： DONG Wei,LIANG EnWei & LU RuiJing physical science & {2. College,guangxi university,nanning 530004,china guangxi Univ Phys Sci & Technol Coll Nanning 530004 Peoples R China

The prompt gamma-ray/X-ray emission of gamma-ray burst(GRB) 0602.8 was simultaneously observed by the Burst Alert Telescope(BAT) and X-ray Telescope(XRT) onboard *** peak energy of the joint νfν spectrum(Ep) clearly evolves with time from tens of keV to-1 keV,crossing both the BAT and XRT *** best fit yields log Ep=(4.61± 0.2.)+(-1.2.±0.08) log t,with a correlation coefficient of 0.98 and a chance probability of p37,is much shallower than that observed in typical GRB *** of this shallowness is presented.

关键词： gamma-ray bursts gamma-rays observations high-energy phenomenon radiation mechanism

X-ray flares of γ-ray bursts: Quakes of solid quark stars?

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science china(Physics,Mechanics & Astronomy) 2009年第2期52卷 315-320页

作者： XU RenXin1 & LIANG EnWei2.1 school of Physics and State Key Laboratory of Nuclear Physics and technology, Peking {2., Beijing 100871, china 2.Department of Physics, guangxi university, nanning 530004, china 1. school of Physics and State Key Laboratory of Nuclear Physics and technology Peking University Beijing 100871 China 2. Department of Physics Guangxi University Nanning 530004 China

A star-quake model is proposed to understand X-ray flares of both long and short γ-ray bursts (GRBs) in a solid quark star regime. Two kinds of central engines for GRBs are available if pulsar-like stars are actually (solid) quark stars, i.e., the SNE-type GRBs and the SGR-type GRBs. It is found that a quark star could be solidified about 103 to 106 s later after its birth if the critical temperature of phase transi- tion is a few Metga-electron-volts, and then a new source of free energy (i.e., elastic and gravitational ones, rather than rotational or magnetic energy) could be possible to power GRB X-ray flares.

关键词： γ-rays bursts: X-rays neutron stars elementary particles

A computer simulation of nucleation and growth of thin films

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science china(Physics,Mechanics & Astronomy) 2004年第4期47卷 442-451页

作者： ZHENG Xiaoping1,ZHANG Peifeng2.HE Deyan2.LIU Jun2. MA Jiantai3 1. Key Laboratory of Opto-Electronic technology and Intelligent Control, Ministry of Education, Lanzhou Jiaotong university, Lanzhou 730070,{2. 2. school of physical science and technology, Lanzhou university, Lanzhou 730000,{2. 3. school of Chemistry and Chemistry Engineering, Lanzhou university, Lanzhou 730000,{2. 1. Key Laboratory of Opto-Electronic technology and Intelligent Control Ministry of Education Lanzhou Jiaotong University 730070 Lanzhou China 2. school of physical {2. and technology Lanzhou University 730000 Lanzhou China 3. school of Chemistry and Chemistry Engineering Lanzhou University 730000 Lanzhou China

A three-dimensional kinetic Monte Carlo technique has been developed for simulating the nucleation and growth of thin films. This model involves incident atom attachment, surface diffusion of the atoms on the growing surface and atom detachment from the growing surface. It takes some new effects into account, such as a significant improvement in calculation of activation energy for the atom diffusion, which renders the model more reasonable. In addition three optimum temperatures and the consistency of their dependence on deposition rate have been found out; the dependence of the surface roughness and relative density on the deposition rate has been discussed; and the approximation of freezing neighbour atoms and periodic boundary conditions has been applied.

关键词： Monte Carlo, thin film, nucleation, surface roughness, relative density.

Asymptotic normality and strong consistency of maximum quasi-likelihood estimates in generalized linear models

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science china Mathematics 2006年第2期49卷 145-157页

作者： YIN Changming, ZHAO Lincheng & WEI Chengdong school of Mathematics and Information science,{2., Manning 530004, china Department of Statistics and Finance, university of science and technology of china, Hefei 2.002., china Department of Mathematics, guangxi Teacher College, Manning 530001, china 1. school of Mathematics and Information science Guangxi University Nanning 530004 China 2. Department of Statistics and Finance University of Science and Technology of China Hefei 230026 China 3. Department of Mathematics Guangxi Teacher College Nanning 530001 China

In a generalized linear model with q x 1 responses, the bounded and fixed (or adaptive) p × q regressors Zi and the general link function, under the most general assumption on the minimum eigenvalue of ZiZ'i,the moment condition on responses as weak as possible and the other mild regular conditions, we prove that the maximum quasi-likelihood estimates for the regression parameter vector are asymptotically normal and strongly consistent.

关键词： generalized linear models quasi-likelihood estimates asymptotic normality strong consistency.

The characteristics of arc beam shaping in hybrid plasma and laser deposition manufacturing

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science china(Technological sciences) 2006年第2期49卷 238-247页

作者： ZHANG Hai’ou1, QIAN Yingping1,3, WANG Guilan1 & ZHENG Qiguang2.1. school of Material science and {2., Huazhong university of science and {2., Wuhan 430074, china 2. Institute of Laser {2. and Engineering, Huazhong university of science and {2., Wuhan 430074, china 3. Mechanical Engineering College, Hubei university of {2., Wuhan 430068, china 1. school of Material science and {2. Huazhong University of Science and Technology Wuhan 430074 China 3. Mechanical Engineering College Hubei University of Technology Wuhan 430068 China 2. Institute of Laser technology and Engineering Huazhong University of Science and Technology Wuhan 430074 China

As a new direct metal prototyping technology,the hybrid plasma and laser deposition manufacturing (PLDM) is proposed in this paper. In order to figure out the characteristics of plasma arc beam and mould in the PLDM process of high temperature alloy, the high speed CCD camera is used to obtain the picture around the plasma arc. Afterwards the sketch of picture is clearly obtained. And the effect of laser parameter, such as average power, pulse width, pulse repetition frequency and the angle between laser beam and plasma arc beam on the plasma arc appearance, is studied experimentally. The results show that the modality of plasma arc beam is markedly influenced by laser beam. And the improvements of shape precision and surface state of the layer deposited by PLDM are confirmed.

关键词： plasma hybrid laser, direct deposition, plasma arc beam, molding character, high-temperature alloy.

Dynamic Modeling of Key Operating Parameters for Supercritical Circulating Fluidized Bed Units based on Data-Knowledge-Driven Method

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Journal of Thermal science 2024年第3期33卷 1216-1230页

作者： YU Haoyang GAO Mingming ZHANG Hongfu CHEN Jiyu LIU Jizhen YUE guangxi The State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources School of Control and Computer EngineeringNorth China Electric Power UniversityBeijing102206China CHN Energy New Energy technology Research Institute Co. Ltd.Beijing102209China Department of Energy and Power Engineering Tsinghua UniversityBeijing100084China

To address the pressing need for intelligent and efficient control of circulating fluidized bed(CFB)units,it is crucial to develop a dynamic model for the key operating parameters of supercritical circulating fluidized bed(SCFB)***,data-knowledge-driven dynamic model of bed temperature,load,and main steam pressure of the SCFB unit has been ***,a knowledge-driven method is employed to develop a dynamic model for key operating parameters of SCFB *** model parameters are determined based on the operating data of the unit and continuously optimized in real ***,Bidirectional Long Short-Term Memory combined with Convolutional Neural Network and Attention Mechanism is utilized to build the dynamic model of bed temperature,load,and main steam ***,a collaboration and integration method based on the critic weight method and the variation coefficient method is proposed to establish data-knowledge-driven model of key operating parameters for SCFB *** model displays great accuracy and fitting ability compared with other methods and effectively captures the dynamic characteristics,which can provide a research basis for the design of intelligent flexible control mode of SCFB unit.

关键词： circulating fluidized bed dynamic model data-knowledge-driven method deep learning power plant

Uniform estimate for maximum of randomly weighted sums with applications to insurance risk theory

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science china Mathematics 2005年第10期48卷 1379-1394页

作者： WANG Dingcheng~1 SU Chun~2.& ZENG Yong~1 1. school of Management and school of Applied Mathematics,{2. of Electronic science and technology of china,Chengdu 610054,china 2. Department of Statistics and Finance,{2. of science and technology of china,Hefei 2.002.,china 1. school of Management and school of Applied Mathematics University of Electronic Science and Technology of China 610054 Chengdu China 2. Department of Statistics and Finance University of Science and Technology of China 230026 Hefei China

This paper obtains the uniform estimate for maximum of sums of independent and heavy-tailed random variables with nonnegative random weights, which can be arbitrarily dependent of each other. Then the applications to ... 详细信息

关键词： dependent stochastic return, discount factor, heavy-tails, discrete time insurance risk model, maxima of randomly weighted sums, ruin probability, tail probabilities, uniformly asymptotic estimate.