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Corrosion behavior of three Ag–50Cu alloys prepared by different processes in NaCl solutions

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Rare Metals 2017年第1期36卷 61-68页

作者： Zhong-qiu Jia qiu-Ying Liang qiu-Yue tian Zhong-qiu Cao Yan Wang College of Chemistry-and Chemical Engineering Shenyang Normal University Shenyang 110034 China

Corrosion behavior of two nanocrystalline bulk Ag–50Cu alloys and one coarse-grained counterpart prepared by liquid-phase reduction(LPR), mechanical alloying(MA) and powder metallurgy(PM) methods,respectively, were investigated in Na Cl solutions. They were finished by means of PARM273 A and M5210 electrochemical apparatus through potentiodynamic polarization method and electrochemical impedance spectroscopy(EIS) technique. The results show that corrosion rates of three Ag–50Cu alloys increase with the increment of Na Cl solution concentrations. Corrosion rates of LPRAg–50Cu alloy are a little higher than those of PMAg–50Cu alloy,but evidently lower than those of MAAg–50Cu alloy. The difference in corrosion rates is attributed to the large reduction in the grain size and homogeneous microstructure of nanocrystalline alloys. Passive current densities decrease and afterward increase for PMAg–50Cu alloy,decrease for MAAg–50Cu alloy, and increase for LPRAg–50Cu alloy with the increment of Na Cl solution concentrations. After the grain sizes are refined, passive current densities become lower.

关键词： Copper alloys Corrosion Corrosion rate Corrosive effects Electrochemical corrosion Electrochemical impedance spectroscopy Electrochemistry Grain size and shape Mechanical alloying Nanocrystals Powder metallurgy Reduction Silver Silver alloys

Insight into the change in carbon structure and thermodynamics during anthracite transformation into graphite

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International Journal of Minerals,Metallurgy and Materials 2020年第2期27卷 162-172页

作者： tian qiu Jian-guo Yang Xue-jie Bai National Engineering Research Center of Coal Preparation and Purification China University of Mining and TechnologyXuzhou 221116China School of Chemical Engineering and Technology China University of Mining and TechnologyXuzhou 221116China

The thermodynamic and kinetic mechanisms of Taixi anthracite during its graphitization process were *** understand the variation trends of carbon arrangement order,microcrystal size,and graphitization degree against temperature during the graphitization process,a series of experiments were performed using Raman spectroscopy and X-ray diffraction(XRD).Subsequently,the influencing factors of the dominant reaction at different temperatures were analyzed using thermodynamics and *** results showed that the graphitization process of Taixi anthracite can be divided into three stages from the perspective of reaction thermodynamics and *** played a crucial role in the formation and growth of a graphitic ***,multivariate mechanisms coexisted in the graphitization *** ultrahigh temperatures,the defects of synthetic graphite could not be completely eliminated and perfect graphite crystals could not be *** low temperatures,the reaction is mainly controlled by dynamics,while at high temperatures,thermodynamics dominates the direction of the reaction.

关键词： anthracite graphitization thermodynamics kinetics

Effects of swirl and hot streak on thermal performances of a high-pressure turbine

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Chinese Journal of Aeronautics 2023年第5期36卷 250-267页

作者： Shenghui ZHANG Shuiting DING Peng LIU tian qiu National Key Laboratory of Science and Technology on Aero-Engine Aero-thermodynamics School of Energy and Power EngineeringBeihang UniversityBeijing 100191China Research Institute of Aero-Engine Beihang UniversityBeijing 100191China

Advanced civil aero-engines tend to adopt lean burn combustors to meet emission *** exit of a lean burn combustor experiences highly non-uniformities in both temperature(Hot Streak,HS)and flow(swirl).This paper presents a numerical investigation on the behaviors of a High-Pressure(HP)turbine under a combined effect of swirl and hot *** investigation was conducted on a GE-E3 HP turbine with unsteady numerical simulations,which considered the realistic clocking position of the HP Nozzle Guide Vane(NGV)relative to the *** influences of swirl orientations on the HS migration and thermal performances on the blade surface were *** indicate that,inside the NGV passage,the swirl’s induced incidence angle effect dominates the HS radial *** transversal movement of HS follows the cross flow and thus makes itself approach the Suction Side(SS)and keep away from the Pressure Side(PS)as passing through the NGV,so that HS near the SS is more influenced by the incidence angle effect than that near the *** for the heat transfer,swirl affects the Heat Transfer Coefficient(HTC)on the NGV’s PS and SS mainly through the incidence angle *** from the NGV,the inlet swirl and HS have limited effect on the HTC on the rotor blade’s PS,while on the rotor blade’s SS,the original vortex system dominates;therefore,the inlet non-uniformities merely enhance the HTC on the SS rather than alter its distribution characteristics.

关键词： High-pressure turbine Hot streak Thermal performances Swirl Orientations Vortex

Engel Condition and p-nilpotency of Finite Groups

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Acta Mathematica Sinica,English Series 2021年第9期37卷 1465-1470页

作者： Lei WANG Zheng tian qiu Shou Hong QIAO School of Mathematics and Statistics Yunnan UniversityKunming 650091P.R.China School of Applied Mathematics Guangdong University of TechnologyGuangzhou 510520P.R.China

Let G be a finite group,and let P be a Sylow p-subgroup of *** the hypothesis that NG(P)is p-nilpotent,we provide some conditions to give a p-nilpotency criterion of finite groups by Engel condition,which improves som... 详细信息

关键词： Finite group p-nilpotency Engel condition p-nilpotent residual

Five Years of IGCP 649 Project-Diamonds and Recycled Mantle

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Acta Geologica Sinica(English Edition) 2020年第S1期94卷 1-3页

作者： YANG Jingsui SHEN Tingting ZHANG Cong qiu tian Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China School of Earth Sciences and Engineering Nanjing UniversityNanjing 210023China

The IGCP-649 project―Diamonds and Recycled Mantle‖is an International Geosciences Program sponsored by UNESCO and IUGS in March *** is a global research project,aimed to carry out extensive and systematic research on peridotites,chromitites and related materials such as diamond,moissanite and other unusual minerals,from different ophiolites in global orogenic belts,for understanding the formation and origin of deepmantle minerals in oceanic lithosphere,the origin of carbon for the ophiolite-hosted diamonds,the evolution of Earth’s mantle and the dynamic process of ophiolite *** IGCP-649 project(2015–2019)is undertaken by the Center for Advanced Research on the Mantle(CARMA),leading by *** Yang,Institute of Geology,Chinese Academy of Geological Sciences,and cooperated by an international team of researchers including *** Dilek of Miami University(USA),*** L Griffin of Macquarie University(Australia),*** *** of Dalhousie University(Canada),*** Milushi of Polytechnic University of Tirana(Albania),and *** Metwaly Abu Anbar of Tanta University(Egypt).

关键词： IGCP mantle minerals

Sleeping of a Complex Brain Networks with Hierarchical Organization

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Communications in Theoretical Physics 2009年第1期51卷 97-100页

作者： ZHANG Ying-Yue YANG qiu-Ying CHEN tian-Lun Department of Physics Nankai University Tianjin 300071 China

The dynamical behavior in the cortical brain network of macaque is studied by modeling each cortical area with a subnetwork of interacting excitable neurons. We characterize the system by studying how to perform the transition, which is now topology-dependent, from the active state to that with no activity. This could be a naive model for the wakening and sleeping of a brain-like system, i.e., a multi-component system with two different dynamical behavior.

关键词： self-organized criticality hierarchical organization EEG-like wave cortical network sleeping

Effects of Vertex Activity and Self-organized Criticality Behavior on a Weighted Evolving Network

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Communications in Theoretical Physics 2008年第8期50卷 421-424页

作者： ZHANG Gui-Qing YANG qiu-Ying CHEN tian-Lun Department of Physics Nankai University Tianjin 300071 China

Effects of vertex activity have been analyzed on a weighted evolving *** network is characterized by the probability distribution of vertex strength,each edge weight and evolution of the strength of vertices with different vertex *** model exhibits self-organized criticality *** probability distribution of avalanche size for different network sizes is also *** addition,there is a power law relation between the size and the duration of an avalanche and the average of avalanche size has been studied for different vertex activities.

关键词： weighted evolving network vertex activity power-law self-organized criticality

Report on the Third IGCP-649 International Workshop on the Mayarí-Baracoa Ophiolites and Chromitites, Cuba

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Acta Geologica Sinica(English Edition) 2017年第6期91卷 2305-2309页

作者： YANG Jingsui qiu tian Angelica I.LLANES CASTRO CARMA Institute of GeologyChinese Academy of Geological Sciences Geological Society of Cuba

During April 3rd-14th, the Third International Ophiolite Workshop of the International Geoscience Programme ＂Diamonds and Recycled Mantle＂（IGCP-649） was successfully held in Havana, Cuba （Fig. 1a）. After the workshop, participants participated in a field trip to the Mayari-Baracoa ophiolites and related chromitites in eastern Cuba （Fig. lb）. This Third International Ophiolite Workshop was jointly organized by the IGCP-649 Project Team and the Cuban Geological Survey. This workshop was included in a special session of the VII Cuba Earth Science Convention. Since the 1980s, diamond,

关键词： Report on the Third IGCP-649 International Workshop the Mayari-Baracoa

Reliability criterion of film capacitor based on moisture diffusion in encapsulation

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High Voltage 2023年第6期8卷 1242-1252页

作者： Zheng Li Hua Li tian qiu Fuchang Lin Yucheng Wang School of Electrical and Electronic Engineering Huazhong University of Science and TechnologyWuhanChina State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and TechnologyWuhanChina Key Laboratory of Pulsed Power Technology Ministry of EducationWuhanChina

The current reliability criterion(RC)of the film capacitor(FC)is usually a fixed value,which does not consider the staged capacitance loss caused by moisture diffusion under high temperature and/or high *** expected lifetime of capacitors would deviate far from the actual *** moisture diffusion process of the encapsulated FC is ana-lysed based on Fick's second *** order to investigate the capacitance loss and moisture diffusion characteristics,4 types of film capacitors are stressed with AC voltage under different temperatures and *** on the staged analysis of the capacitance and weight gain curves,the effect of moisture diffusion on capacitance loss is *** indicate that the linear stage of capacitance loss corresponds to the Fickian moisture diffusion stage of weight *** effect of voltage on FC aging is the most *** capacitance loss rate increases by 301%when the voltage rises by 30%.An RC calculation method of the FC is further proposed,which could also screen the encap-sulation quality and shorten the aging test duration by at least 80%.

关键词： aging moisture diffusion