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Active metal brazing of SiO2–BN ceramic and Ti plate with Ag–Cu–Ti＋BN composite filler

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Journal of Materials Science & Technology 2017年第11期33卷 1392-1401页

作者： z.w.Yang C.l.wang Y.wang l.X.zhang D.P.wang J.C.Feng Tianjin Key lab of Advanced Joining Technology School of Materials Science and Engineering Tianjin University Tianjin 300072 China State Key lab of Advanced welding andJoining Harbin Institute of Technology Harbin 150001 China

SiO2–BN ceramic and Ti plate were joined by active brazing in vacuum with Ag–Cu–Ti＋BN composite *** effect of BN content,brazing temperature and time on the microstructure and mechanical properties of the brazed joints was *** results showed that a continuous Ti N–Ti B2reaction layer formed adjacent to the SiO2–BN ceramic,whose thickness played a key role in the bonding *** Ti–Cu compound layers,Ti2Cu,Ti3Cu4,Ti Cu2and Ti Cu4,were observed to border Ti substrate due to the strong affinity of Ti and Cu compared with *** central part of the joint was composed of Ag matrix,over which some fine-grains *** added BN particles reacted with Ti in the liquid filler to form fine Ti B whiskers and Ti N particles with low coefficients of thermal expansion（CTE）,leading to the reduction of detrimental residual stress in the joint,and thus improving the joint *** maximum shear strength of 31 MPa was obtained when 3 wt%BN was added in the composite filler,which was 158%higher than that brazed with single Ag–Cu–Ti filler *** morphology and thickness of the reaction layer adjacent to the parent materials changed correspondingly with the increase of BN content,brazing temperature and holding *** on the correlation between the microstructural evolution and brazing parameters,the bonding mechanism of SiO2–BN and Ti was discussed.

关键词： SiO2–BN ceramic BN particles Microstructure Mechanical properties

Predicting release and aquatic effects of total dissolved solids from Appalachian USA coal mines

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International Journal of Coal Science & Technology 2014年第2期1卷 152-162页

作者： w.l.Daniels C.E.zipper z.w.Orndorff Department of Crop and Soil Environmental Sciences Virginia TechBlacksburgVA 24061USA

Appalachian USA coal mines have been implicated as major stressors to aquatic life in headwater streams via discharge of total dissolved solids(TDS).This paper summarizes column leaching studies of spoils(n>50)and refuse and TDS effects on local water quality and biotic *** initial pH of most materials is *** specific conductance(SC)values range from 500-1,000 to >3,000 μs/cm,but 2/3 of materials drop below 500 ls/cm after several pore volumes of *** of mining-influenced streams have found altered aquatic life,relative to natural conditions with no mining influence,at SC ranging from-200 to-700 ls/cm with depressed aquatic life consistently associated with elevated TDS;mechanisms causing such effects are under *** suggest that active mine operations should be modified to place high TDS producing materials in ways that reduce contact with percolating drainage waters.

关键词： Mine spoil weathering-Acid base accounting water quality Valley fills

Contamination by Organochlorine Pesticides in the Estuaries of Southeast China

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Chemical Research in Chinese Universities 2002年第2期18卷 153-160页

作者： z.l.zhang H.S.Hong J.l.zhou M.H.Dai K.Maskaouib w.Q.Chen Department of Environmental Science and Engineering Tsinghua POPs Research CentreTsinghua UniversityBeijing 100084China Key laboratory of Marine Environmental Science of Ministry of Education Environmental Science Research CentreXiamen Universi-tyXiamen 361005China School of Chemistry Physics and Environmental ScienceUniversity of SussexFalmerBrighton BN19QJUK

Persistent organic pollutants(POPs) such as organochlorine pesticides are of global concern due to their widespread occurrence and persistence. This paper reports recent research studying the distribution and fate of organochlorine pesticides in the Jiul.ng River, the Minjiang River and the Pearl River estuaries in Southeast China. Eighteen organochlorine pesticides were extracted from water, pore water and sediment samples, followed by analysis by GC ECD. The results showed that the contamination levels were similar in these three estuaries. The levels of the total organochlorine pesticides in porewater were significantly higher than those in surface water, due to the high affinity of these hydrophobic compounds for sediment phase. Among the hexachlorocyclohexane(HCH) compounds, β HCH was found to be the most important isomer. The analysis of 1,1,1 trichloro 2,2 bis chlorophenyl ethane(DDT) and its metabolites showed that 1,1 dichloro 2[ o chlorophenyl] 2[ p chlorophenyl] ethylene(DDE) was dominant in the group.

关键词： Organochlorine insecticides DDT lindane Jiul.ng River Estuary Minjiang River Estuary Pearl River Estuary water Sediment

Microstructure Evolution of in situ (Ti3AlC+Ti5Si3 )/Ti3Al Composite Sheet with a Novel Quasi-continuous Chain Reinforcement Distribution Architecture Prepared by Using Roll Bonding and Reaction Anneal.ng

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Journal of Materials Science & Technology 2013年第12期29卷 1191-1196页

作者： J.C.Pang G.H.Fan X.P.Cui A.B.li l.Geng z.z.zheng Q.w.wang School of Materials Science and Engineering Harbin Institute of Technology

The Ti3Al matrix composite sheet with a novel quasi-continuous chain reinforcement distribution was prepared by using roll bonding and subsequent reaction anneal.ng with pure Ti and SiCp/Al *** (Ti3AlC t Ti5Si3) reinforcements were produced by in situ reaction of the as-rolled Tie(SiC p/Al) laminated composite sheet after a two-stage anneal.ng treatment including first anneal.ng at 660 C and second anneal.ng at 1250 *** microstructure evolution during the reaction anneal.ng was *** the first reaction anneal.ng,TiAl3was formed,and the SiC particles were pushed together due to the Kirkendall effect,and after the second reaction anneal.ng,Ti3Al,Ti3AlC and Ti5Si3were *** addition,the reinforcement distribution presents a quasi-continuous chain microstructure in Ti3Al matrix composite sheet.

关键词： Composite Intermetallic Fabrication Reaction synthesis

PRECIPITATION AND GROwTH OF PEROVSKITE PHASE IN TITANIUM BEARIng BlAST FURNACE SlAG

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Acta Metallurgica Sinica(English letters) 2007年第1期20卷 9-14页

作者： z.z. Guo T.P. lou l. zhang l.N. zhang z.T. Sui School of Materials and Metallurgy Northeastern University Shenyang 110006 Ghina

The effects of transformation of slag composition and additive agents on the morphology, the precipitation behavior, the crystal growth, and the volume fraction (VF) of perovskite (CaO·¤TiO_2) crystal in the Ti-bearing blast furnace slags were investigated. As the morphology of perovskite is dispersed in molten slags, the crystal growth mechanism of the melting of fine dendrites and the coarsening of large grains exist throughout the solidification of molten slags. with the increase of CaO and Fe_2O_3 content, VF of perovskite obviously increases. However, high basicity leads to the viscosity of slag, which results in the reduction of the average equivalent diameter (AED). The experimental results showed that the presence of the additives CaF_2 and MnO efficiently decreased the viscosity of the slags, and obviously improved the morphology of perovskite and promoted its growth.

关键词： perovskite phase Ti-bearing blast furnace slag precipitation additive agent

Microstructure and Strain Hardening of a Friction Stir welded High-Strength Al–zn–Mg Alloy

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Acta Metallurgica Sinica(English letters) 2014年第4期27卷 723-729页

作者： A.H.Feng D.l.Chen z.Y.Ma w.Y.Ma R.J.Song School of Materials Science and Engineering Tongji University State Key laboratory of Advanced welding Production Technology School of Materials Science and EngineeringHarbin Institute of Technology Department of Mechanical and Industrial Engineering Ryerson UniversityTorontoON M5B 2K3Canada Shenyang National laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

Microstructural evolution and strain hardening behavior of a friction stir welded（FSwed） high-strength7075Al-T651 alloy were *** nugget zone was observed to consist of fine and equiaxed recrystallized grains with a low dislocation density and free of original precipitates,but containing uniformly distributed *** strength,joint efficiency,and ductility of the FSwed joints increased with increasing welding speed.A joint efficiency of ＊91% was achieved at a welding speed of 400 mm/min and rotational rate of 800 r/min,while the ductility remained basically the same as that of the base *** was no obvious strain rate sensitivity observed in both base metal and welded *** both the base metal and FSwed joints exhibited stage III and IV hardening characteristics,the hardening capacity,strain hardening exponent,and strain hardening rate all increased after friction stir welding.

关键词： Aluminum alloy Friction stir welding Mechanical properties Strain hardening

前言:青藏高原及其周边综合地层、生物群与古地理演化

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中国科学：地球科学 2024年第4期54卷 911-914页

作者：沈树忠丁林朱茂炎王向东邓涛南京大学地球科学与工程学院关键地球物质循环前沿科学中心内生金属成矿机制研究国家重点实验室南京210023 中国科学院青藏高原研究所青藏高原地球系统全国重点实验室北京100101 中国科学院南京地质古生物研究所现代古生物学和地层学国家重点实验室南京210008 中国科学院大学地球与行星科学学院北京100049 中国科学院古脊椎动物与古人类研究所中国科学院脊椎动物演化与人类起源重点实验室北京100044

青藏高原研究对揭示地史时期全球构造、古地理、生物与环境等的演化都具有举足轻重的作用.文章介绍了“青藏高原及其周边综合地层、生物群与古地理演化”专辑的组织背景、主要内容和期望目标,同时总结了本专辑成果相比第一次青藏高原科... 详细信息

青藏高原研究对揭示地史时期全球构造、古地理、生物与环境等的演化都具有举足轻重的作用.文章介绍了“青藏高原及其周边综合地层、生物群与古地理演化”专辑的组织背景、主要内容和期望目标,同时总结了本专辑成果相比第一次青藏高原科考报告的显著进展.

关键词：期望目标生物群全球构造生物与环境青藏高原周边

Formation of Nonlinear Solitary Vortical Structures by Coupled Electrostatic Drift and Ion-Acoustic waves

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Chinese Physics letters 2017年第12期34卷 41-45页

作者： l.z.Kahlon I.Javaid Physics Department Forman Christian CollegeFerozpur Road 54600LahorePakistan

Propagation of coupled electrostatic drift and ion-acoustic waves（DIAws） is presented. It is shown that nonlinear solitary vortical structures can be formed by low-frequency coupled electrostatic DIAws. Primary waves of distinct（small, intermediate and large） scales are considered. Appropriate set of 3 D equations consisting of the generalized Hasegawa-Mima equation for the electrostatic potential（involving both vector and scalar nonlinearities） and the equation of motion of ions parallel to magnetic field are obtained. According to experiments of laboratory plasma mainly focused to large scale DIAws, the possibility of self-organization of DIAws into the nonlinear solitary vortical structures is shown analytically. Peculiarities of scalar nonlinearities in the formation of solitary vortical structures are widely discussed.

关键词： Formation of Nonlinear Solitary Vortical Structures by Coupled Electrostatic Drift and Ion-Acoustic waves

Effects of Curing Condition on the Carbonation of Shrinkage-compensated Concrete

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武汉理工大学学报 2010年第17期32卷 103-107页

作者： MA J T TU l Q SHUI z H CHEN w School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China wuhan Harbour Engineering Design & Research Co. ltd Wuhan 430071China

Shrinkage-compensating concrete can enhance the permeability and strength. In addition,expansive admixture can densify concrete to advance the carbonation resistance ability. Due to special quality of ettringite,the relative humidity of curing environment has significant effect on the carbonation rate of concrete. This paper discusses the influence of environmental humidity on carbonation rate of shrinkage-compensating concrete. Four different curing conditions were set up,namely the natural environment (RH 60%),standard environment (RH 90%),early age water curing environment for 3 d and 7 d. After curing in these four environments for 28 d,an accelerated carbonation test was performed. Micro-hardness analysis was used to evaluate surface hardness,which depends on,to a great degree,the carbonation depth. TG-DSC analysis was used to study Ca(OH)2 content gradient in the surface layer of concrete in different environment. The results show that natural condition lead to a relatively worse carbonation degree,curing in water for 3 d is harmful to the carbonation resistance,while curing in water for 7 d lead to an equivalent carbonation degree with standard condition,which show the most improvement to carbonation resistance ability.

关键词： shrinkage-compensating concretes curing humility ettringite reaction carbonation rate