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LASER LIFT-OFF OF GaN THIN FILMS FROM SAPPHIRE SUBSTRATES

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Acta Metallurgica Sinica(English Letters) 2001年第6期14卷 448-452页

作者： J. xu, R. Zhang, Y.P. wang, x.q. xiu, S.L. Gu, B. Shen, Y. Shi, Z.G. Liu and Y.D. Zheng (Department of Physics and National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China) Dept. of Phys. Nanjing Univ. Nanjing 210093 China

Gallium Nitride film was successfully separated from sapphire substrate by laser radiation. The absorption of the 248 nm radiation by the GaN at the interface results in rapid thermal decomposition of interfacial layer, yielding metallic Ga and N2 gas. The substrate can be easily removed by heating above the Ga melting point (29°C). x-ray diffraction, atomic force microscopy and photoluminescence of GaN before and after lift-off process have been performed, which demonstrated that the separation and transfer process do not alter the structural quality of the GaN films. And further discussions on the threshold energy and crack-free strategies of laser lift-off process have also been presented.

关键词： Gallium compounds Laser beam effects Nitrides Sapphire Separation

New Vacuum System for SFC

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New Vacuum System for SFC

CHARACTERIZATION OF Si_(1-x-y)Ge_xC_y FILMS GROWN BY ION IMPLANTATION AND SUBSEqUENT SOLID PHASE EPITAxY

The Second Asian Particle Accelerator Conference

作者： D.Z. Wu, Y.F. wang, x.q. Zhang, J.Y. TangIMP, Lanzhou, China

The old vacuum chamber of the injector SFC was built for internal PIG ion source and foraccelerating ions lower than *** the axial injection from ECR ion source and theacceleration range extending to Uranium,both theoretical and experimental studies showedthat the old vacuum of 1×10Pa was not sufficient to accelerate heavy ions.A new vacuumsystem has been designed and manufactured to provide the mean vacuum pressure of 1×*** new vacuum chamber has been designed to have double layers structure,where the

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来源： cnki会议评论

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Acta Metallurgica Sinica(English Letters) 2002年第1期15卷 49-52页

作者： x.q. Liu Y.Y. wang W.J. Cheng J. Zhang S.Y. Ma Dept. of Phys. Lanzhou Univ. Lanzhou 730000 China

Si1-x-yGexCy ternary alloy films were grown on monocrystalline silicon substrates by C+ ion implantation and subsequent solid phase epitaxy (SPE). Two-step annealing technique was employed in the SPE. The structure and electrical properties of the alloy films were determined using Fourier transform infrared spectroscopy and van der Pauw Hall measurements, respectively. With the optimization of two-step annealing technique for the implanted Si1-x-yGexCy layers, a certain amount of C atoms occupied substitutional sites and no SiC was formed.

关键词： Si1-x-yGexCu film ion implantation SPE

“绿水青山就是金山银山”解题新机制——“优质地理产品生境保护与可持续发展”2021-2030十年行动计划正式启动

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全球变化数据学报（中英文） 2021年第3期5卷 237-248,376-387页

作者：刘闯龚克刘燕华廖小罕王振波何昌垂罗晖周翔童庆禧闵庆文武建军桂东伟陈军王萍萍鹿飞周蕾孙永武杨晓李军王秀全田宏张国友陈从喜郭鹏梁英徐贵川张振兴余学勇张晓东 Ahmat M.Issa 宋献方王正兴付晶莹王永生祝晓光张立福诸云强于伯华王冠一林刚代辛吕一河中国科学院地理科学与资源研究所北京100101 世界工程组织联合会(WFEO) 巴黎南开大学天津300071 中华人民共和国科学技术部北京100036 联合国粮食与农业组织意大利罗马北京大学北京100871 中国国际科技交流中心北京100081 中国科学院空天信息创新研究院北京100101 北京师范大学地理科学部北京100875 中国科学院新疆生态与地理研究所乌鲁木齐830011 中国地理基础信息中心北京100830 吉林省磐石市人民政府磐石132300 江苏省丰县县委丰县221700 山东省禹城市委宣传部禹城251299 宁夏回族自治区盐池县农村农业局盐池751500 四川省遂宁市农村农业局遂宁629018 中国期刊学会北京100005 中国科学院科学传播局北京100864 中国科学院自然科学期刊编辑研究会北京100190 中国地理学会北京100101 中国自然资源学会北京100101 中国通用咨询投资有限公司北京100161 航天科工海鹰集团有限公司北京100048 禹城市交融创业集团有限公司禹城251299 启源渔业科技有限公司北京100097 中关村一带一路产业促进会北京100190 北京天航华创科技股份有限公司北京100085 天津中科谱光信息技术有限公司天津300392 青海省社会科学院西宁810099 中国生态学会北京100085

在由中国科学院地理科学与资源研究所、世界工程组织联合会共同组织的“2021年中国世界服务贸易交易会世界工程组织联合会展厅优质地理产品生态环境保护与可持续发展论坛”上,来自30个单位和学术组织代表就国内外形势——机遇与挑战,科... 详细信息

在由中国科学院地理科学与资源研究所、世界工程组织联合会共同组织的“2021年中国世界服务贸易交易会世界工程组织联合会展厅优质地理产品生态环境保护与可持续发展论坛”上,来自30个单位和学术组织代表就国内外形势——机遇与挑战,科学、技术与工程——把论文写作祖国的大地上,践行“绿水青山就是金山银山”发展理念——政府的作用,科学传播与科学文化的引导作用,学术团体的作用,服务贸易中的机遇、问题与解决方案等议题的研讨达成共识,正式启动“优质地理产品生态环境保护与可持续发展2021-2030十年行动计划”。该行动计划的核心是在未来十年内,通过产、学、研、政、团、民、传协作的机制,采取在生态环境、产品质量、经营管理、地理传统方面具有典型引领意义案例的方式,践行“二山”、对标联合国2030可持续发展目标。本文通过盐池滩羊花马池镇干草原案例(宁夏)等11个案例实践表明本次大会提出的解题“绿水青山就是金山银山”的新机制将有利于2030可持续发展目标的实现。

关键词：优质地理产品生境保护可持续发展 2021-2030 十年行动计划

MICROSTRUCTURE EVOLUTION AND MECHANICAL HARDENING OF HYPEREUTECTOID PEARLITIC STEEL DURING COLD ROLLING

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Acta Metallurgica Sinica(English Letters) 2007年第4期20卷 287-292页

作者： x. Zhang C.x. wang x.M. Liu q.N. Shi Key Laboratory of Advanced Materials of Yunnan Province Kunming University of Science and Technology Kunming 650093 China Institute for Structural Materials Central Iron and Steel Research InstituteBeijing 100081 China

The microstructure evolution of different cold rolling reductions （from 0 to 81.6%） was studied by SEM （scanning electron microscopy） and TEM （transmission electron microscope）. The study showed that the orientation multiplicity of pearlitic lamellas resulted in inhomogeneous deformation of different pearlitic lamellas, and with the increase of reduction, the microstructure underwent a course of ＂homogeneity → inhomogeneity → homogeneity＂. The result of xRD （x-ray diffraction） analysis indicated that cementite did not decompose and dissolve into ferrite; the results of the mechanical property test suggested that the relationship between Rp0.2 （yield strength） and ε （true strain） was in good agreement with Hollomon relationship. With the equation Rp0.2 = 1465ε^0.18, the yield strength of the steel in different reductions could be well predicted.

关键词： cold rolling hypereutectoid pearlitic steel microstructure evolution mechanical hardening

First-principles Investigation of Bi Segregation at the Solder Interface of Cu/Cu_3Sn(010)

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Journal of Materials Science & Technology 2010年第12期26卷 1057-1062页

作者： x.Y. Pang Z.q. Liu S.q. wang J.K. Shang Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Department of Materials Science and Engineering University of Illinois at Urbana-Champaign IL 61801 USA

Density functional theory was employed to investigate the bismuth segregation at Cu/Cu3Sn（010） interface. Five initial constructions were introduced by adopting the adhesion energy criterion. Among them, the so-called ＂between-Cu＂ construction in which the interface Cu atoms of Cu slab locate along Cu-Cu bond direction in Cu3Sn slab was found to be the most energy-favored at an adhesion energy of 1.96 J/m^2. Based on this construction, five possible segregation sites were examined, and the most likely segregation site was determined with adhesion energy as low as 1.06 J/m^2, which was almost half of the initial one. Comparing with other sitest adhesion energies, it was concluded that size effect took a large part in embrittlement. The analyses of atomic structure and electronic density revealed that the slabs shifted away from interfaces due to bismuth segregation, and the atoms around Bi atom were Dressed away. This calculated work agreed aualitativelv with reported experimental results.

关键词： First-principles calculation Segregation Bismuth Interface SnBi solder

Effect of Nb-V microalloying on the hot deformation behavior of medium Mn steels

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 360-368页

作者： Yumeng wang qinyi Guo Bin Hu Haiwen Luo School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China

The influence of Nb-V microalloying on the hot deformation behavior and microstructures of medium Mn steel(MMS)was investigated by uniaxial hot compression *** establishing the constitutive equations for simulating the measured flow curves,we successfully constructed deformation activation energy(q)maps and processing maps for identifying the region of flow *** concluded the following consequences of Nb-V alloying for MMS.(i)The critical strain increases and the increment diminishes with the increasing deformation temperature,suggesting that NbC precipitates more efficiently retard dynamic recrystallization(DRx)in MMS compared with solute Nb.(ii)The deformation activation energy of MMS is significantly increased and even higher than that of some reported high Mn steels,suggesting that its ability to retard DRx is greater than that of the high Mn content.(iii)The hot workability of MMS is improved by narrowing the hot processing window for the unstable flow stress,in which fine recrystallized and coarse unrecrystallized grains are present.

关键词： medium manganese steel niobium-vanadium microalloying flow behavior dynamic recrystallization hot workability

Effects of Current Stressing on Shear Properties of Sn-3.8Ag-0.7Cu Solder Joints

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Journal of Materials Science & Technology 2010年第8期26卷 737-742页

作者： x.J. wang q.L. Zeng q.S. Zhu Z.G. wang J.K. Shang Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Department of Materials Science and Engineering University of Illinois at Urbana-Champaign Urbana IL 61801 USA

Effects of electromigration on microstructure, shear strength, and fracture behavior of solder joints were investigated by single-ball shear samples of eutectic Sn-3.8Ag-0.7Cu （SAC） joined by Cu plates at two sides. The electromigration tests were conducted at a current density of about 1.1×10^3 A/cm2 and a working temperature of about 83℃. The results showed that the shear strength and flow stress decreased greatly after current stressing. Such a decrease was associated with no significant loss of the fracture strain at short electromigration but a great reduction in the fracture strain after long-term current stressing. The variation of the fracture strain with the electromigration time was shown to result from the shift of the fracture surface from the center of the solder towards the intermetallic compound （IMC） interface at the cathode.

关键词： Strength Fracture strain Voids Solder

A Diagram for Glass Transition and Plastic Deformation in Model Metallic Glasses

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Journal of Materials Science & Technology 2014年第6期30卷 546-550页

作者： x.q.Gao W.H.wang H.Y.Bai Institute of Physics Chinese Academy of Sciences

In this paper, we report a strain rate related glass transition in model SrCaYbMg（Li）Zn（Cu） metallic glasses at room temperature. A critical strain rate, equivalent to glass transition temperature, is found for the strain rate induced glassy state to liquid-like viscoplastic state translation. The results show that the observation time, equivalent to temperature and stress, is a key parameter for the transition between the glass and supercooled liquid states. A three-dimension glass transition diagram involved in time, temperature and stress in metallic glasses is established.

关键词： Homogeneous plastic flow Glass transition Metallic glass