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Kinetics of Al Evaporation from Liquid U-Al Alloys in Vacuum Induction Melting

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Journal of Materials Science & Technology 2015年第4期31卷 423-426页

作者： y.J.Duan B.chen y.C.Ma K.Liu Materials for Special Environment Division Institute of Metal ResearchChinese Academy of Sciences

A research on kinetics of Al evaporation from liquid U—Al alloys was made in a vacuum induction melting（VIM） furnace at 1673—1843 *** evaporation rate of Al was found to be first order with respect to Al content in the *** overall mass transfer coefficient of Al was determined and it was found that the evaporation rate of Al increased with increasing *** apparent activation energy of Al evaporation at 1673-1843 K was 171.5 kJ *** value of mass transfer coefficient of Al in the liquid phase was estimated to be 3.77 × 10-6,7.41×10-6,and 9.40 × 10-6m s-1at 1673,1753,and 1843 K,***,rate determining steps were discussed and it was concluded that the evaporation rate of Al is mainly controlled by liquid phase mass transfer.

关键词： Al evaporation Kinetics Liquid U-Al alloys Mass tr

FEM SIMULATION FOR LASER FORMING PROCESSING

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Acta Metallurgica Sinica(English Letters) 2004年第3期17卷 317-322页

作者： L.Q.Li y.B.chen X.y Wang S.y Lin State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China Harbin Research Institute of Welding Harbin 150001 ChinaState Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China Harbin Research Institute of Welding Harbin 150001 ChinaHarbin Research Institute of Welding Harbin 150001 ChinaHarbin Research Institute of Welding Harbin 150001 China

Laser forming involves heating sheet metal workpiece along a certain path with adefocused laser beam directed irradiate to the surface. During laser forming, a tran-sient temperature fields is caused by the irradiation and travelling of a laser beam.Consequently, thermal expansion and contraction take place, and allows the thermal-mechanical forming of complex shapes. This is a new manufacturing technique thatforming metal sheet only by thermal stress. Therefore, the analysis of temperaturefields and stress fields are very useful for studying the forming mechanism and con-trolling the accuracy of laser forming. The non--liner finite element solver, MARC, isemployed to solve the thermal--mechanical analysis. Using this model, the stress andstrain distribution of pure aluminum plate with different thickness are analyzed. Theinfluence of scanning speed on temperature fields and plastic strain of metal sheet un-der the condition of constant line energy are also presented. Numerical results agreewell with the experimental results.

关键词： laser forming FEM simulation temperature fields stress distributton

The dynamic responses of lamellar and equiaxed nearβ-Ti alloys subjected to multi-pass cross rolling

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Journal of Materials Science & Technology 2020年第8期36卷 220-229页

作者： Wei chen Hande Wang y.C.Lin Xiaoyong Zhang Chao chen yaping Lv Kechao Zhou State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China School of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China

This work gives a comparison on the microstructural characteristics,textural discrepancies,and twinning behaviors of lamellar and equiaxed nearβ-Ti alloys during multi-pass cross rolling with a rolling reduction of 20%,50%and 80%.The results showed that the restoration mechanism of the alloy inβphase is strongly dependent on theαmorphologies,and in comparison,strain path has weaker influences on the grain refinement of theβ***,the texture intensities of bothαandβphases were weakened owing to the dynamic recrystallization(DRX)of the two phases in the equiaxed ***,with regard to the lamellar microstructure,dynamic recovery(DRV)of theβphase predominated,forming elongatedβ***,theαandβmatrix in lamellar microstructures obeyed the Burgers orientation relationship,which was gradually broken down until the final ***,the{1101}twinning exhibits a strong size *** the continuous DRX ofαphases,theα-twinning is suppressed owing to progressive grain *** activation ofβ-twinning,namely{332}?113?and{112}?111?,in nearβ-Ti alloys is heavily dependent on the deficientβ-stabilizing elements and the local stress *** findings provide an effective way to obtain ultra-fine grain microstructures of this alloy.

关键词： Nearβ-Ti alloys Multi-pass cross rolling Dynamic recrystallization {1101}Twinning β-twinning

A new type of oceanic crust and its dynamical significance

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Chinese Science Bulletin 1997年第1期42卷 54-57页

作者： Zhang, Q Zhou, DJ chen, y Institute of Geology Chinese Academy of Sciences Beijing China

THE oceanic lithosphere is composed of oceanic crust and upper mantle. It is widely accepted that the Troodos ophiolitic section represents the oceanic crust section, which consists of ultramafic cumulates in the bottom, and grades upward into cumulative gabbros, isotropic gabbro, sheeted dikes and pillow lavas, covered by abyssal sediments. According to the marine geophysical investigation, the oceanic crust can be divided into three layers which from top to bot-

关键词： oceanic crust ophiolite oceanic ridge dynamics.

Solid-state alloying of Al-Mg alloys by accumulative roll-bonding:Microstructure and properties

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Journal of Materials Science & Technology 2022年第30期125卷 238-251页

作者： X.M.Mei Q.S.Mei J.y.Li C.L.Li L.Wan F.chen Z.H.chen T.Xu y.C.Wang y.y.Tan School of Power and Mechanical Engineering Wuhan UniversityWuhan 430072China Key Laboratory of Hydraulic Machinery Transients(Wuhan University) Ministry of EducationWuhan 430072China School of Mechanical Engineering Wuhan Polytechnic UniversityWuhan 430023China

In this study,a novel solid-state alloying approach was adopted to fabricate Al-Mg alloys with high Mg contents(C_(Mg)) by accumulative roll-bonding(ARB)of Al and Mg elemental materials to ultrahigh *** results showed that the degree of alloying increased with the increase of ARB cycles and a supersaturatedα-Al solid solution accompanied with nanoprecipitates was formed in the Al-Mg alloys by ARB to 70 *** as-prepared Al-Mg alloys exhibited enhanced mechanical properties,with a maximum tensile strength of∼615 MPa and a tensile elongation of∼10%at C_(Mg)=13 wt.%.The high strength can be attributed to different mechanisms,namely solid solution strengthening,grain boundary strengthening,dislocation strengthening,and precipitation *** Al-Mg alloys showed increased work hardening with increasing C_(Mg),due to the enhanced formation of ***,no obvious drop in the intergranular corrosion(IGC)resistance was found in the Al-Mg alloys with C_(Mg) up to 13 wt.%.Moreover,sensitization treatment was found to induce little decrease in the IGC resistance of the Al-Mg alloys with C_(Mg)≤13 wt.%.We found that the excellent IGC resistance was due to the suppression of grain boundary precipitation by the preferred formation of precipitates within the grains that were induced by *** study indicated the novelty of the present solid-state alloying approach to achieving a superior combination of high mechanical properties and IGC resistance in Al-Mg alloys.

关键词： Solid-state alloying Al-Mg alloys Mechanical properties IGC resistance ARB

Total integration method of three-dimensional fluorescence spectrometry

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Chinese Science Bulletin 1997年第18期42卷 1541-1544页

作者： yan, y Xu, JG chen, GZ XIAMEN UNIV DEPT CHEMRES LAB SEDC ANALYT SCI MAT & LIFE CHEMXIAMEN 361005PEOPLES R CHINA

THREE-dimensional fluorescence spectrometry (TDFS) is a new technique of spectrofluorimetry that was developed two decades *** use of the abundant information

关键词： three-dimensional fluorescence spectrometry fluorescence Monte-Carlo integration.

On the mechanism of Si-promoted destabilization of TiC_(x)particles in Al alloys

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Journal of Materials Science & Technology 2023年第34期165卷 17-26页

作者： H.Dong y.C.Guo y.Z.chen F.Xia Q.Q.Guo Q.chen G.L.Li J.y.Zhao y.Zhong J.P.Li School of Materials and Chemical Engineering Xi’an Technological UniversityXi’an 710021China State Key Lab.of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China School of Science Xi’an University of Science and TechnologyXi’an 710054China

TiC_(x)is an excellent composite strengthening particle and grain refiner for Al ***,the stability of TiC_(x)is poor when solute Si exists in Al alloy melts,which significantly depresses its strengthening and grain refining *** this work,the destabilization mechanisms of the TiC_(x)particles in Al-Si alloy melt with a composition of Al-7Si-7.5TiC were explored via experiments,first-principles calculations and thermodynamic *** experimental results show that Si atoms diffuse into TiC_(x)and Ti atoms are released into the Al melt to form a Ti-rich transition zone during the insulation of TiC_(x)in Al-Si melt,and the TiAlySiz and Al_(4)C_(3)phases are solidified in the Ti-rich zone and at Ti-rich zone/TiC_(x)interface,*** first principles calculations show that the low formation energy of C vacancies facilitates the rapid diffusion of Si atoms in TiC_(x),while the doping of Si atoms reduces the energy barrier of diffusion of Ti atoms in TiC_(x)and promotes the formation of Ti-rich *** thermodynamic calculations show that the wide crystallization temperature range of the destabilized product TiAlySiz phase is the key to continuous decomposition of TiC_(x)*** addition,the driving force of the main destabilization reaction of TiC_(x)in the Al-Si alloys is about 44 times higher than that in the Al alloys without Si *** indicates that the presence of solute Si remarkably promotes the subsequent decomposition process of TiC_(x)in the Al-Si alloy melts.

关键词： Al-Si alloy TiC_(x)particles Destabilization First principles calculations Thermodynamics

An Initial Analysis of a Strongly Lensed QSO Candidate Identified by LAMOST

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Research in Astronomy and Astrophysics 2023年第10期23卷 349-356页

作者： y.H.chen M.y.Tang H.Shu H.Tu Institute of Astrophysics Chuxiong Normal UniversityChuxiong 675000China School of Physics and Electronical Science Chuxiong Normal UniversityChuxiong 675000China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650011China Department of Astronomy Yunnan Universityand Key Laboratory of Astroparticle Physics of Yunnan ProvinceKunming 650091China Physics Department&Shanghai Key Lab for Astrophysics Shanghai Normal UniversityShanghai 200234China

From 2011 to 2021,LAMOST has released a total of 76,167 quasar *** try to search for gravitationally lensed QSOs by limiting coordinate differences and redshift differences of these *** name,brightness,spectrum,photometry and other information of each QSO will be visually checked *** attention should be paid to check whether there are groups of galaxies,gravitationally lensed arcs,Einstein crosses,or Einstein rings near the *** careful selection,we select LAMOST J160603.01+290050.8(A)and LAMOST J160602.81+290048.7(B)as a candidate and perform an initial *** A and B are336 apart and they display blue during photometric *** redshift values of components A and B are0.2%different,their Gaia_g values are 1.3%different,and their ugriz values are 1.0%or less *** the spectra covering from 3690 to 9100?,the emission lines of C II,Mg,Hγ,OⅢ,and Hβare present for both components A and B and the ratio of flux(B)to flux(A)from LAMOST is basically a constant,around ***,no galaxies have been found between components A and *** et *** them as binary *** we accidentally find a galaxy group near components A and *** the center of dark matter in the galaxy group is at the center between components A and B,components A and B are probably gravitationally lensed *** estimate that the Einstein mass is 1.46×10^(11)M_⊙and the total mass of the lens is1.34×10^(13)M_⊙.The deflection angle is 197 at positions A and B and the velocity dispersion is 261 km s^(-1).Theoretically,this candidate could be a pair of fold images of a strong lensing system by a galaxy group,and we will investigate the possibility when the redshifts of nearby galaxies are available.

关键词： gravitational lensing:strong (galaxies:)quasars:individual(LAMOST J1606+2900) techniques:imaging spectroscopy

CyCLIC　VOLTAMMETRy　STUDy　ON　ANTIMALARIAL　MECHANISM　OF　ARTEMISININ（QINGHAOSU）DERIVATIVES

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Chinese Chemical Letters 1996年第7期7卷 623-626页

作者： Jiang, HL chen, KX Tang, y chen, JZ Li, y Wang, QM Li, Q Ji, Ry Zhuang, QK CHINESE ACAD SCI SHANGHAI INST MAT MEDSHANGHAI 200031PEOPLES R CHINA BEIJING UNIV DEPT CHEMBEIJING 100871PEOPLES R CHINA

Cyclic voltammetry method waws used to determine the cyclic voltammogram of artemisininderivatives and reduction potentials(RPs)of these compounds were obtained. Combining the determinationresults of Zhang and co-workers,QSAR analysis was performed between the activity and reductionpotentials(RPs),which illustrated the antimalarial mechanism of artemisinin analogs, The experimentalresult verified and tested our previous theoretical calculation results.

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