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Quantization of black hole entropy from unstable circular null geodesics

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Science China(Physics,Mechanics & Astronomy) 2016年第4期59卷 29-36页

作者： Shao-Wen Wei Yu-xiao liu Chun-E Fu Institute of Theoretical Physics Lanzhou University School of Science Xi'an Jiaotong University

The quasinormal mode frequencies can be understood from the massless particles trapped at the unstable circular null geodesics and slowly leaking out to infinity. Based on this viewpoint, in this paper, we semiclassically construct the entropy spectrum of the static and stationary black holes from the null geodesics. The result shows that the spacing of the entropy spectrum only depends on the property of the black hole in the eikonal limit. Moreover, for a black hole far from the extremal case, the spacing is found to be smaller than 2π for any dimension, which is very different from the result of the previous work by using the usual quasinormal mode frequencies.

关键词： black hole entropy spectrum null geodesics quantization

Secure and Trusted Interoperability Scheme of Heterogeneous Blockchains Platform in IoT Networks

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China Communications 2023年第11期20卷 225-241页

作者： xiao liu Mingyuan Li Haipeng Peng Shoushan Luo School of Electronic Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China

With the rapid development of the Internet of Things(IoT),there is an increasing need for interac-tion between different *** order to improve the level of interconnection,especially the interoper-ability of users/devices between different nodes is very *** the IoT heterogeneous blockchain sce-nario,how to ensure the legitimacy of the chain and how to confirm the identity of cross-chain informa-tion users/devices become the key issues to be solved for blockchain *** this paper,we pro-pose a secure and trusted interoperability mechanism for IoT based on heterogeneous chains to improve the security of blockchain *** this mecha-nism,a primary sidechain architecture supporting au-thentication at both ends of the heterogeneous chain is *** addition,a distributed gateway archi-tecture is proposed for cross-chain authentication and protocol *** security and performance analysis shows that our scheme is feasible and effec-tive in improving the security of cross-chain opera-tions in IoT.

关键词： authentication blockchain Interoperabil-ity heterogeneous chain IoT

Hydrodynamic characteristics of a four-compartment periodic anaerobic baffled reactor

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Journal of Environmental Sciences 2007年第10期19卷 1159-1165页

作者： liu xiao-lei REN Nan-qi WAN Chun-li School of Municipal and Environmental Engineering Harbin Institute of Technology Harbin 150090 China School of Water Conservancy and Environment Engineering Changchun Institute of Technology Changchun 130012 China

Periodic anaerobic baffled reactor （PABR） is a novel reactor based on the design concept of anaerobic baffled reactor （ABR）. Residence time distribution （RTD） studies on both clean and working reactors at the same hydraulic residence time （HRT） of 2 d were carded out to investigate the dead spaces and mixing patterns in PABRs at different organic loading rates （OLRs） in various switching manners and frequencies. The results showed that the fraction of dead space in PABR was similar to that in ABR, which was low in comparison with other reactor designs. Dead space may be divided into two categories, hydraulic and biological. In RTD studies without biomass, the hydraulic dead space in the PABR run in an ＂every second＂ switching manner with T = 2 d was the lowest whereas that in the PABR run in a T = ∞ （ABR） switching manner was the highest. The same trend was obtained with the total dead space in RTD studies with biomass no matter what the OLR was. Biological dead space was the major contributor to dead space but affected decreasingly at higher OLR whichever switching manner the PABR run in. The flow patterns within the PABRs were intermediate between plug-flow and perfectly mixed under all the conditions tested,

关键词： dead space residence time distribution periodic anaerobic baffled reactor anaerobic processes wastewater treatment

A SPLIT-CHARACTERISTIC FINITE ELEMENT MODEL FOR 1-D UNSTEADY FLOWS

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Journal of Hydrodynamics 2007年第1期19卷 54-61页

作者： ZHOU Yi-lin TANG Hong-wu liu xiao-hua State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering College of Water Conservancy and Hydropower Engineering Hohai University Nanjing 210098 China.

An efficient and accurate solution algorithm was proposed for 1-D unsteady flow problems widely existing in hydraulic engineering. Based on the split-characteristic finite element method, the numerical model with the Saint-Venant equations of 1-D unsteady flows was established. The assembled f＇mite element equations were solved with the tri-diagonal matrix algorithm. In the semi-implicit and explicit scheme, the critical time step of the method was dependent on the space step and flow velocity, not on the wave celerity. The method was used to eliminate the restriction due to the wave celerity for the computational analysis of unsteady open-channel flows. The model was verified by the experimental data and theoretical solution and also applied to the simulation of the flow in practical river networks. It shows that the numerical method has high efficiency and accuracy and can be used to simulate 1-D steady flows, and unsteady flows with shock waves or flood waves. Compared with other numerical methods, the algorithm of this method is simpler with higher accuracy, less dissipation, higher computation efficiency and less computer storage.

关键词： split characteristic finite element method,tri-diagonal matrix algorithm 1-D unsteady flow flood wave,river networks

Synthesis, Crystal Structure and Luminescence of a Trinuclear Magnesium Coordination Polymer Based on a Triangle Flexible Carboxylic Ligand

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Chinese Journal of Structural Chemistry 2015年第8期34卷 1288-1294页

作者： WANG Rong-Ming ZHANG Ming-Hui liu xiao-Qing liu xiao-Bin WANG Wen SUN Dao-Feng College of Science China University of Petroleum (East China)

A novel two-dimensional metal organic coordination compound based on flexible 1,3,5-tri（4-carboxyphenoxy）benzene （HaTCPB）, {[Mgl.5（TCPB）（DMF）（H20）]＇（DMF）}n （1）, has been prepared and structurally characterized by single-crystal X-ray diffraction, TGA, and PXRD measurements. Complex 1 crystalizes in triclinic, space group Pi with a = 10.2521（6）, b = 11.0974（7）, c = 16.1113（9） A, C33H31Mg1.5N2012, Mr = 684.06, V= 1669.46（17） A3, Z = 2, Dc = 1.361 g·cm^-3, p = 0.129 mm^-1, F（000） = 714, 3.06≤0≤25°, λ（MoKa） = 0.71073 A, T= 273（2） K, the final R = 0.0386, wR = 0.0892 and S = 1.031. X-ray diffraction analysis reveals that complex 1 possesses a two-dimensional framework constructed by trinuclear Mg SBUs and three-connected TCPB3- linker. In addition, the solid state luminescent property of complex 1 was also investigated at room temperature.

关键词： crystal structure, two-dimensional framework, fluorescence, magnesium

Study on deformation mechanism of Ti-2Al-2.5Zr alloy tube in the flattening test

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Journal of Materials Science & Technology 2021年第31期90卷 108-120页

作者： Shengkun Wang Gang Jin Yuntao Wu xiao liu Gang Chen School of Chemical Engineering and Technology Tianjin UniversityTianjin 300350China Nuclear and Radiation Safety Center MEE54#Beijing 100082China School of Chemical Engineering Sichuan UniversitySichuan 610065China Nuclear Power Institute of China ChengduSichuan 610015China

The flattening test,using one pair paralleled plates to flatten tube structure radially,is generally employed to examine the ductility of tube used in once through steam generator(OTSG).This study focuses on the stress condition and deformation mechanism analysis on the concentrated stress regions of Ti-2 Al-2.5 Zr alloy tube during the flattening ***,the finite element analysis was performed using the commercial software ABAQUS to determine the stress ***,the Electron BackScattered Diffraction(EBSD)was implemented to observe the microstructure evolution of Ti-2 Al-2.5 Zr ***,Schmid law was employed to analyze the activated deformation mechanism under condition of the complex *** was found that the condition of the complex stress in stress concentration regions,including tension and compression regions,can be simplified into two directional stresses *** grains whose c-axis is nearly towards TD and ND,the strain is mainly accommodated by prismatic slip,whereas in grains whose c-axis deviates about 45°from ND to TD mainly by basal ***{10-12}extensive twin and corresponding parent grain orientation mainly relied on the stress ***,the intergranular twin pairs connected at common grain boundaries(GBs)with high strain compatibility were found at low angle GBs,which were activated under a combination of macro stress and strain compatibility effect.

关键词： Ti-2Al-2.5Zr alloy tube Flattening test EBSD Stress condition Deformation mechanism Schmid factor Twin pairs Strain compatibility effect

Estimation of Fracture Toughness for A508-III Steel in Ductile-to-Brittle Transition Region Using a Strain-Energy–Density-Based Fracture Failure Model

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Acta Mechanica Solida Sinica 2022年第5期35卷 834-841页

作者： Yuanjun Wu Chen Bao Lixun Cai Kaiqing Wang xiao liu Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province School of Mechanics and Aerospace EngineeringSouthwest Jiaotong UniversityChengdu610031China Science and Technology on Reactor Fuel and Materials Laboratory Nuclear Power Institute of ChinaChengdu610213China

According to the assumption of intrinsic relationship between ultimate strain energy density and microcrack nucleation,this work developed a fracture failure model to estimate the fracture toughness of A508-III steel in the ductile-to-brittle transition *** fracture toughness and uniaxial tension tests at different temperatures were carried out to determine the relationship between nucleation parameter and ultimate strain energy density,from which the evolutions of fracture toughness of A508-III ferritic steel for different cumulative failure probabilities at different temperatures were *** fracture failure model can well describe the fracture toughness distribution of A508-III steel in the ductile-to-brittle transition *** with the master curve method,this model has better temperature *** is more convenient to calibrate the parameters of this model compared with the traditional Beremin model,and without complex finite element analysis.

关键词： Fracture toughness Cumulative failure probability A508-III steel Ductile-to-brittle transition region

Modelling of Level Fluctuation in Continuous Casting

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Journal of Materials Science & Technology 2003年第z1期19卷 158-160页

作者： xiao liu Huanxin ZHANG Rongjun XU Yongquan LI Houfa SHEN Baicheng liu Baoshan Iron and Steel Co. LTD. Shanghai 201900 China Department of Mechanical Engineering Tsinghua University Beijing 100084 China Baoshan Iron and Steel Co. LTD. Shanghai 201900 China Baoshan Iron and Steel Co. LTD. Shanghai 201900 China Department of Mechanical Engineering Tsinghua University Beijing 100084 China Department of Mechanical Engineering Tsinghua University Beijing 100084 China

The free surface profile and fluid flow in the mold of continuous casting have been calculated by the VOF method couplingthe SIMPLER algorithm. The SIMPLER-VOF model developed is validated by solving a classical experiment, broken damproblem. The calculated surface profile is consistent with water modelling. It is found that the free surface profile is coherentlyrelated to the position of circumfluence in the mold of continuous casting. With the increase of nozzle port inclination, thepositive vortex above the jet is near to the meniscus and the level fluctuation becomes prominent.

关键词： Level fluctuation, Fluid flow, Continuous casting, Numerical simulation

Embedment of red phosphorus in anthracite matrix for stable battery anode

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Rare Metals 2022年第8期41卷 2819-2825页

作者： Yu-Chen Tan Wei-Wei liu Wen-Yu Wang xiao-xiao liu Jun-Mou Du Yong-Ming Sun Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan430074China

Red phosphorus(red P)is a promising anode material for lithium-ion batteries(LIBs)due to its high theoretical capacity of 2596 mAh·g^(-1),abundant resource and low ***,the application of P-based anode suffers from several crucial issues,including limited electronic conductivity and drastic volume variation during its electrochemical lithiation/delithiation ***,we reported a red P/anthracite composite featuring red P embedded into micrometer-sc ale porous anthracite framework fabricated through a one-pot ball milling synthesis process.

关键词： battery anode lithium