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Effect of Bismuth on Intermetallic Compound Growth in Lead Free Solder/Cu Microelectronic Interconnect

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Journal of Materials Science & Technology 2011年第8期27卷 741-745页

作者： T.y. Kang y. y. Xiu L. Hui J.J. Wang W.P. Tong C.Z. Liu Key.Laboratory.of Electromagnetic Processing of Materials Ministry of Education Northeastern University Shenyang 110004 China Sheny.ng Aerospace University Shenyang 110136 China

The intermetallic compound （IMC） growth kinetics in pure Sn/Cu and Sn10 wt%Bi/Cu solder joints was studied, respectively. after they.were aged at 160-210℃ for different time. It was found that the total IMC in Sn10 wt%Bi/Cu joint developed faster than it did in pure Sn/Cu solder joint, when they.were aged at the same temperature. And the activation energy.Qa for total IMC in Sn10 wt%Bi/Cu joint was lower than that for pure Sn/Cu interconnect. The IMC growth process was discussed. The IMC Cu6Sn5 was enhanced in compensation of reduced IMC Cu3Sn growth. The work reveals that Bi element containing in lead free solder alloy. with 10 wt% can enhance IMC growth in lead free solder/Cu joint during service.

关键词： Solder Interfacial reaction Intermetallics Kinetics

Scale Effects of Geographical Soil Datasets on Soil Carbon Estimation in Louisiana,USA:A Comparison of STATSGO and SSURGO

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Pedosphere 2011年第4期21卷 491-501页

作者： B. ZHONG y. J. XU School of Renewable Natural Resources Louisiana State University Agricultural Center Baton Rouge LA 70803 (USA)

Estimation of soil organic carbon （SOC） pools and fluxes bears large uncertainties because SOC stocks vary.greatly.over geographical space and through time. Although development of the U.S. Soil Survey.Geographic Database （SSURGO）, currently.the most detailed level with a map scale ranging from 1：12 000 to 1：63 360, has involved substantial government funds and coordinated network efforts, very.few studies have utilized it for soil carbon assessment at the large landscape scale. The objectives of this study.were to 1） compare estimates in soil organic matter among SSURGO, the State Soil Geographic Database （STATSGO）, and referenced field measurements at the soil map unit; 2） examine the influence of missing data on SOC estimation by.SSURGO and STATSGO; 3） quantify.spatial differences in SOC estimation between SSURGO and STATSCO, specifically.for the state of Louisiana; and 4） assess scale effects on soil organic carbon density.（SOCD） estimates from a soil map unit to a watershed and a river basin scale. SOC was estimated using soil attributes of SSURGO and STATSGO including soil organic matter （SOM） content, soil lay.r depth, and bulk density. Paired t-test, correlation, and regression analy.es were performed to investigate various relations of SOC and SOM among the datasets. There were positive relations of SOC estimates between SSURGO and STATSGO at the soil map unit （R2 = 0.56, n = 86, t = 1.65, P = 0.102; depth： 30 cm）. However, the SOC estimated by.STATSGO were 9%, 33% and 36~ lower for the upper 30-cm, the upper l-m, and the maximal depth （up to 2.75 m） soils, respectively. than those from SSURGO. The difference tended to increase as the spatial scale changes from the soil map unit to the watershed and river basin scales. Compared with the referenced field measurements, the estimates in SOM by.SSURGO showed a closer match than those of STATSCO, indicating that the former was more accurate than the latter in SOC estimation, both in spatial and temporal resoluti

关键词： carbon accounting climate change GIS soil organic carbon soil organic matter

Forest biodiversity. relationships to structural and functional attributes, and stability.in New England forests

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Forest Ecosy.tems 2018年第2期5卷 177-188页

作者： y.de Pan Kevin McCullough David y. Hollinger USDA Forest Service Durham NH USA USDA Forest Service Madison WI USA

Background： Forest biodiversity.is the foundation of many.ecosy.tem services, and the effect of biodiversity.on ecosy.tem functioning and processes （BEF） has been a central issue in biodiversity.studies. Although many.hy.otheses have been developed to interpret global gradients of biodiversity. there has not been complete agreement on mechanisms controlling biodiversity.patterns and distributions. Differences may.be due to limited observation data and inconsistencies of spatial scales in analy.is. Methods： In this study. we take advantage of USDA Forest Service forest inventory.and analy.is （FIA） data for exploring regional forest biodiversity.and BEF in New England forests. The FIA data provide detailed information of sampled plots and trees for the region, including 6000 FIA plots and more than 33,000 individual trees. Biodiversity.models were used to analy.e the data. Results： Tree species diversity.increases from the north to the south at a rate about 2-3 species per latitudinal degree. Tree species diversity.is better predicted by.tree height than forest age or biomass. Very.different distribution patterns of two common maple species, sugar maple （Acer sdcchorum） and red maple （Acer rubrum）, highlight the vulnerability.of sugar maple and its potential replacement by.red maple on New England landscapes. Red maple generally.already.outperforms sugar maple, and will likely.and continuously.benefit from a changing climate in New England. Conclusions： We conclude that forest structure （height） and resources （biomass） are more likely.foundational characteristics supporting biodiversity.rather than biodiversity.determining forest productivity.and/or biomass. The potential replacement of red maple for sugar maple in the New England areas could affect biodiversity.and stability.of forest ecosy.tem functioning because sugar maple play. important ecological roles distinct from red maple that are beneficial to other tree species in northern hardwood forests. Such a change

关键词： Forest biodiversity Biodiversity.effect on function (BEF) New England Forest inventory.data Species diversity Latitudinal diversity.gradient Forest stability.of ecosy.tem functioning Forest resilience Sugar maple Red maple Changing climate

Tuning periodicity.of poly.er-decorated carbon nanotubes

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Science China Chemistry 2012年第5期55卷 802-807页

作者： LAIRD Eric D. LI Christopher y. A. J. Drexel Nanotechnology.Institute and Department of Materials Science and Engineering Drexel University Philadelphia Pennsylvania 19104 USA

Carbon nanotube (CNT) is one of the most extensively.investigated nanomaterials. Patterning soft matter such as liquid cry.tals and poly.ers on CNTs could potentially.enable various applications for CNTs. We have demonstrated that controlled poly.er cry.tallization using CNTs as the 1D nucleation sites can lead to periodically.functionalized CNTs. Here we show that selected cry.talline block copoly.ers can be periodically.decorated along CNTs. This facile technique opens a gateway.to periodic patterning on 1-D nanomaterials.

关键词： poly.er cry.tallization carbon nanotube block copoly.ers

Topological Poly.er Chemistry.for Designing New Macromolecular Architectures

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复旦学报（自然科学版） 2005年第5期44卷 844-845页

作者： y. Tezuka Department of Organic and Poly.eric Materials Tokyo Institute of Technology Tokyo 152-8552 Japan

The precise control in poly.er architectures has been an ongoing challenge in sy.thetic poly.er chemistry. since new poly.er topologies will realize unprecedented properties and functions in poly.eric *** particular, topologically.unique macromolecules comprising single cy.lic and multicy.lic poly.er units have gained growing interests due to their distinctive behaviors from linear and branched counterparts[1-4]. See Fig. 1.

关键词：遥爪聚合体拓扑结构静电自组合大分子结构合成方法

Asy.metry.aware load balancing for parallel applications in single-ISA multi-core sy.tems

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Journal of Zhejiang University.Science C(Computers and Electronics) 2012年第6期13卷 413-427页

作者： Eunsung KIM Hy.onsang EOM Heon y. y.OM School of Computer Science and Engineering Seoul National University Seoul 151-744 Korea

Contemporary.operating sy.tems for single-ISA （instruction set architecture） multi-core sy.tems attempt to distribute tasks equally.among all the CPUs. This approach works relatively.well when there is no difference in CPU capability. However, there are cases in which CPU capability.differs from one another. For instance, static capability.asy.metry.results from the advent of new asy.metric hardware, and dy.amic capability.asy.metry.comes from the operating sy.tem （OS） outside noise caused from networking or I/O handling. These asy.metries can make it hard for the OS scheduler to evenly.distribute the tasks, resulting in less efficient load balancing. In this paper, we propose a user-level load balaneer for parallel applications, called the ＇capability.balancer＇, which recognizes the difference of CPU capability.and makes subtasks share the entire CPU capability.fairly. The balancer can coexist with the existing kemel-level load balancer without detrimenting the behavior of the kernel balancer. The capability.balancer can fairly.distribute CPU capability.to tasks with very.little overhead. For real workloads like the NAS Parallel Benchmark （NPB）, we have accomplished speedups of up to 9.8% and 8.5% in dy.amic and static asy.metries, respectively. We have also experienced speedups of 13.3% for dy.amic asy.metry.and 24.1% for static asy.metry.in a competitive environment. The impacts of our task selection policies, FIFO （first in, first out） and cache, were compared. The use of the cache policy.led to a speedup of 5.3% in overall execution time and a decrease of 4.7% in the overall cache miss count, compared with the FIFO policy. which is used by.default.

关键词： Scheduler Load balancing Capability.asy.metry OS noise Multi-core

Sy.thesis and Thermal Property.of the Poly.silpheny.lenesiloxane)s with Functional Groups

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复旦学报（自然科学版） 2005年第5期44卷 798-799页

作者： y. Kawakami Japan Advanced Institute of Science and Technology.(JAIST) 1-1 Asahidai Nomi Ishikawa 923-1292 Japan

Silicon-containing poly.ers have been intensively.studied in the past half-century. and a great number of papers, patents and books have been published on the sy.thesis, properties and applications. Silicon-containing poly.ers, especially.poly.ers containing silicon atoms in the backbone, including some major species as poly.iloxane, poly.ilane, poly.ilazane, etc. have chains constructed of alternately.arranged silicon and oxy.en atoms with organic groups attached to the silicon atoms, which are the most important silicon-containing poly.ers so far.

关键词：聚乙烯热性质功能组氢化硅烷化

MICROSTRUCTURE AND MECHANICAL PROPERTy.DEVELOPMENT IN THE SIMULATED HEAT AFFECTED ZONE OF V TREATED HSLA STEELS

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Acta Metallurgica Sinica(English Letters) 2006年第1期19卷 57-67页

作者： y. T. chen A.M. Guo L.X. Wu J. Zeng P.H. Li National Enterprise Technology.Center Wuhan Iron and Steel （Group） Co.Wuhan 430080 China

The simulated heat affected zone （HAZ） of the high strength low alloy.（HSLA） steels containing 0%, 0.047%, 0.097% and 0.151% vanadium, respectively. were studied with Gleeble-2000 thermomechanical simulator to determine the influence of vanadium addition on the mechanical properties of the HAZ. The HAZ simulation involved reheating the samples to 1350℃, and then cooling to ambient temperature at a cooling rate of 5℃/s ranging from 800 to 500℃ （△8/5=60s）. The mechanical properties including tensile strength and -20℃ impact toughness were conducted. The microstructures of the base steel and the simulated HAZs were investigated using optical microscope, scanning electron microscope （ SEM ） and transmission electron microscope （TEM）. Based on the sy.temutic examination, the present work confirmed that about 0.05% vanadium addition to low carbon low alloy.steels resulted in expected balance of strength and toughness of the HAZ. And more than 0.10% levels addition led to detrimental toughness of the HAZ SEM study.showed that the simulated 0.097% and 0.151%V HAZs consisted of more coarse ferrite plates with greater and more M-A constituents along austenite grain and ferrite plate bound- aries. The impact fracture surfaces of the simulated 0.097% and 0.151%V HAZs showed ty.ically.brittle mode with predominant cleavages. The size of the facet in the fracture surface increased with increasing vanadium level from 0.097% to 0.151%.As a result, the simulated 0.151% V HAZ has the lowest impact toughness of the four specimens.

关键词： vanadium high strength low alloy.(HSLA) steel mechanical property.heat affected zone (HAZ)

Enhancement of Sinter Densification of SrO-BaO-Nb_2O_5-SiO_2 Tungsten-Bronze Glass-Ceramics by.Doping with P_2O_5

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Journal of Materials Science & Technology 2013年第8期29卷 731-736页

作者： J.C.chen y.Zhang Sheny.ng Research and Development Centre for Advanced Materials Institute of Metal ResearchChinese Academy of Sciences State Key.Laboratory.of New Ceramics and Fine Processing Institute of Nuclear and New Energy TechnologyTsinghua University

Densification behaviors of SrO-BaO-Nb2O5-SiO2 based glass-ceramics prepared by.conventional sintering were investigated with an emphasis on the influence of P2O5 content. Although P2O5 dopant did not modify.the surface cry.tallization mechanism, it resulted in a decrease of the glass transition temperature, which facilitates the viscous glass flow necessary.for sintering. However, premature cry.tallization of （Sr, Ba）Nb2O6 induced by.addition of excess amount of P2O5 essentially.retarded sintering due to the formation of closed pores in the matrix. The SrO-BaO-Nb2O5-SiO2 glass with 1.0 mol% P2O5 （SBN-1P） showed the best sinter densification, which was accomplished at about 850 ℃.

关键词： Sintering densification DieLectric properties Glass-ceramic