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EVOLUTION Of MICROSTRUCTURE Of Sn-Ag-Cu LEAD-fREE fLIP CHIP SOLDER JOINTS DURING AGING PROCESS

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Acta Metallurgica Sinica(English Letters) 2006年第4期19卷 301-306页

作者： Y.H. Tian C.Q. wang w.f. Zhou State Key Lab of Advanced welding Production and Technology Harbin Institute of Technology Harbin 150001 China

flip chip bonding has become a primary technology that has found application in the chip interconnection process in the electronic manufacturing industry in recent years. The solder joints of the flip chip bonding are small and consist of complicated microstructures such as Sn solution, eutectic mixture, and intermetallic compounds （IMCs）, whose mechanical performance is quite different from the original solder bulk. The evolution of microstructure of the flip chip solder joints under thermal aging was analyzed. The results show that with an increase in aging time, coarsening of solder bulk matrix and AuSn4 IMCs occurred within the solder. The IMCs that are formed at the bottom side of the flip chip bond were different from those on the top side during the aging process. （Cu, Ni, Au）0Sn5 were formed at the interfaces of both sides, and large complicated （Au,Ni, Cu）Sn4 IMCs appeared for some time near the bottom interface after aging, but they disappeared again and thus （Cu,Ni, Au ）0Sn5 IMC thickness increased considerably. The influence of reflow times during the flip chip bonding （as-bonded condition） on the characteristics of interfacial IMCs was weakened when subjected to the aging process.

关键词： lead free solder flip chip aging

HEAT TRANSfER ANALYSIS DURING ROLLING Of THIN SLAB IN CSP

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Acta Metallurgica Sinica(English Letters) 2006年第4期19卷 244-250页

作者： w.f. wu Y.H. feng X.X. Zhang Inner Mongolia University of Science and Technology Baotou 014010 China University of Science and Technology Beijing Beijing 100083 China

A mathematical model has been built to numerically predict the thermal history of thin slab during CSP （compact strip process） rolling. To estimate the temperature distribution in the slab mare accurately, the mathematical model combines heat transfer in the slab, in the roll, and at the roll-slab interface during bite. The numerical results agree with on-site running data, which proves the reliabili~, of the mathematical model. The results show that roll chilling has a significant effect on the temperature distribution in the slab.

关键词： numerical simulation heat transfer CSP(compact strip process) rolling thermal process

PRECIPITATION BEHAVIOR Of M_(2)N IN A HIGH-NITROGEN AUSTENITIC STAINLESS STEEL DURING ISOTHERMAL AGING

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Acta Metallurgica Sinica(English Letters) 2007年第2期20卷 95-101页

作者： f. Shi L.J. wang w.f. Cui C.M. Liu School of Materials ＆ Metallurgy Northeastern UniversityShenyang 110004 China

The precipitation behavior of M2N and the microstructural evolution in a Cr-Mn austenitic stainless steel with a high nitrogen content of 0.43mass% during isothermal aging has been investigated using optical microscopy （ OM）, scanning electron microscopy （SEM）, and transmission electron microscopy （TEM）. The aging treatments have led to the decomposition of nitrogen supersaturated austenitic matrix through discontinuous cellular precipitation. The precipitated cells comprise alternate lamellae of M2N precipitate and austenitic matrix. This kind of precipitate morphology is similar to that of pearlite. However, owing to the non-eutectoidic mechanism of the reaction, the growth characteristic of the cellular precipitates is different from that of pearlite in fe-C binary alloys. M2N precipitate in the cell possesses a hexagonal crystal structure with the parameters a = 0.4752nm and c = 0.4429nm, and the orientation relationship between the M2V precipitates and austenite determined from the SADP is [01^-10]M2N//[101]γ, [2^-1^-10]M2N//[010]γ.

关键词： austenitic stainless steel high nitrogen microstructureisothermal aging precipitation

Missense mutations of the fibrillin-1 gene in two Chinese patients with severe Marfan syndrome

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Chinese Medical Journal 2001年第5期114卷 25-28页

作者： Ivan f.M. LO, Rosanna M.S. wONG, fanny w.f. LAM, Tony M.f. TONG and Stephen T.S. LAM Clinical Genetic Service Department of Health 3/F Cheung Sha Wan Jockey Club Clinic 2 Kwong Lee Road Shamshuipo Kowloon Hong Kong Special Administrative Region China. akyblue@***

Objective To describe two Chinese patients with severe forms of Marfan syndrome and to report findings of mutational analysis of the fibrillin-1 (fBN1) *** Two Chinese patients were studied, one suffering from Marfan syndrome of infantile onset and the other of neonatal onset. Their clinical features were described. Mutational analysis of the fBN1 gene was performed using polymerase chain reaction (PCR) technique and direct sequencing of exons 23 - 32,where the mutational hotspots for severe forms of Marfan syndrome are *** Two missense mutations were successfully identified, a G3037A transition and an A3083T transversion, the latter being an unreported *** Taking advantage of the clustering phenomenon of mutations in severe forms of Marfan syndrome, one can identify fBN1 mutations in these patients by first screening the mutational hotspots,thus reducing the effort that would otherwise be much greater because of the size of the gene.

关键词： Marfan syndrome fibrillin-1 mutation

Development and Validation of an Instrument to Measure STEM Undergraduate Students’ Comprehensive Educational Process

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frontiers of Education in China 2019年第4期14卷 575-611页

作者： ZHUANG Tengteng CHEUNG Alan C.K. LAU wilfred w.f. TANG Yipeng Department of Educational Administration&Policy Faculty of EducationThe Chinese University of Hong KongHong KongChina Department of Curriculum and Instruction Faculty of EducationThe Chinese University of Hong KongHong KongChina College of Education Capital Normal UniversityBeijing 100089China

This study reports the development and validation of an instrument,“Undergraduate STEM Educational Process Questionnaire”(USEPQ)to assess the learning experiences of STEM(science,technology,engineering and mathematics)-major undergraduates from the perspective of a conceptualized comprehensive STEM educational process framework that consists of key essentials such as course learning and instruction,educational environment,assessment methods,and unique STEM *** factor Analysis and Confirmatory factor Analysis performed on independent samples indicate that the finalized 9-factor,41-item USEPQ possesses a stable factor structure and sound psychometric *** factors of the validated scale are Classroom Instruction of Courses,Support from faculty Members,Alternative Assessment Methods,Cooperative Learning,Resources and Service,Academic Competition,Cross-discipline features of Program Courses,Connectedness of Program Courses,and Examination Difficulty.

关键词： higher education educational process STEM program,measurement instrument development and validation

A Study on Maintaining Strategies of Landscape Ecology in Rural Areas

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A Study on Maintaining Strategies of Landscape Ecology in Ru...

Structural and tectonothermal evolution of the ultrahigh-temperature Bakhuis Granulite Belt,Guiana Shield,Surinam:Palaeoproterozoic to recent

第三世界生态高峰会

作者： Hsieh w.f. Department of Horticulture Chum-Shing Taiwan.

Ecological environment of rural areas in Taiwan had been seriously threatened by the increasing urban ***,the related regulations and policies as guidelines for protecting ecological environment of rural areas in Taiwan had not been completely ***,it is urgent to propose strategies for maintaining rural areas' natural environment and ecology to avoid the continuous environmental *** study is based upon the theory of landscape *** using structure,function,and change as major principles,current issues of landscape ecology in rural areas of Taiwan were *** propose the appropriate strategies for protecting, maintaining,and rebuilding rural areas' landscape and ecology,data collection and integration of literature review,related regulations,and policies were used in this *** reviewing and analyzing the related information,the study proposed strategies for different space scales,including development strategies(avoiding and compensating) for bigger space scale(e.g.,proposing the best route by using the map of landscape unit analysis)and development strategies(shrinking and augmenting)for smaller space scale(e.g.,introducing ecological engineering method into the constructions of riverbank,roadside,pond, etc.).Rural landscape planning should select natural preservation areas as core areas,rural areas as buffer zones,corridors,and development *** study had integrated the planning concept of landscape ecology and useful strategies for illustrated areas(Shi-Tan).The comprehensive ecological networks for Shi-Tan were also proposed. The study suggested that related agencies make efforts on establishing fallows,wetlands,and subsidizing corridor development to become ecological ***,the utmost task is to build up data base of local ecological resources for facilitating the further tracing and residents' training to help environmental monitoring and achieve sustainable development purpose for rural areas

关键词： landscape ecology strategy conservation of rural area

来源： cnki会议评论

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cnki会议

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Geoscience frontiers 2021年第2期12卷 677-692页

作者： frank f.Beunk Emond w.f.de Roever Keewook Yi fraukje M.Brouwer faculty of Science Geology and Geochemistry ClusterVrije Universiteit Amsterdam(VUA)De Boelelaan 10851081HVAmsterdamthe Netherlands Division of Earth and Environmental Sciences Korean Basic Science InstituteOchang363-833South Korea

we constrain the multistage tectonic evolution of the Palaeoproterozoic UHT metamorphic(P=0.9–1.0 GPa,T>1000℃,t=2088–2031 Ma)Bakhuis Granulite Belt(BGB)in Surinam on the Guiana Shield,using large-to small-scale structures,Al-in-hornblende thermobarometry and published fluid inclusion and zircon geochronological *** BGB forms a narrow,NE–Sw striking belt between two formerly connected,~E–w oriented granite-greenstone belts,formed between converging Amazonian and west African continental masses prior to collision and Transamazonian *** detrital zircon in BGB metasediments conforms agewise to Birimian zircon of west Africa and suggests derivation from the subsequently subducted African passive ***-temperature metamorphism may have followed slab break-off and asthenospheric heat *** metamorphic structures result from layer-parallel shearing and folding,reflecting initial transtensional exhumation of the subducted African margin after slab break-off.A second HT event involves intrusion,at ca.0.49 GPa,of charnockites and metagabbros at 1993–1984 Ma and a layered anorthosite at 1980 Ma,after the BGB had already cooled toward subduction under the greenstone belts,along a new active margin to their south.A pronounced syntaxial bend in the new margin points northward towards the BGB and is likely the result of indentation by an anticlinorial flexural bulge of the subducting *** of the subducting oceanic plate along this bulge explains why the charnockites are restricted to the *** BGB subsequently experienced doming under an extensional detachment exposed in its southwestern border *** was focused in the BGB as a result of the flexural bulge in the subducting plate and localised heating of the overriding plate by charnockite *** present,straight NE–Sw long-side boundaries of the BGB are superimposed mylonite zones,overprinted by pseudotachylites,previously dated

关键词： Bakhuis granulite belt Guiana shield Transamazonian orogeny UHT metamorphism Tectonics P-T-t evolution

A MULTIPLE STRUCTURE RECONSTRUCTION ALGORITHM BASED ON wIRE fRAME MODEL

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Computer Aided Drafting,Design and Manufacturing 1997年第1期7卷 36-44页

作者： Du Jiangchuan Paul w.f. Poon

A “LAG & RLC” visualization algorithm has been presented to display a clear three dimensional structure from stereo slice data which has the characteristics of multiple layer structure. This algorithm is based on wire frame model which can do multiple logical operations and has multiple display effects. It has wide use in biomedical science and computer graphics. The practical system is based on PC with a TVGA adapter at least 512k byte display memory and 2M byte extended memory.

关键词： LAG & RLC visualization three dimensional reconstruction wire frame model multiple structure

A NEw NON-UNIfORM YIELD PHENOMENON AND ITS MECHANISM

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Acta Metallurgica Sinica(English Letters) 2000年第3期13卷 862-866页

作者： w.f. Zhang Y.M. Chen and J.H. Zhu(State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China)

A new non-uniform yield phenomenon is found during tension of austenite stainless steel at -190℃, which consists of elasto-plastic instability ξph and stress plateau ξL resulting from strain-induced martensite transformation. It is essentially different from non-uniform yield that is related to dislocation obstacles. The experimental results show that ξph and ξL increase with increaslng strain rate, and ξph, increases but ξL decreases with increasing *** enengy of strain-induced martensite keeps a constant, 3.85×106J/m3, with increasing strain at the stages of both elasto-plastic instability and stress plateau.

关键词： non-uniform yield elasto-plastic instability stress plateau,strain-induced martensite transformation