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Semi-transparent,flexible,and electrically conductive silicon mesh by capillarity-driven welding of vapor-liquid-solid-grown nanowires over large areas

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Nano Research 2020年第5期13卷 1465-1471页

作者： Thomas A.Celano Seokhyoung Kim David j.Hill james f.Cahoon Department of Chemistry University of North Carolina at Chapel HillChapel HillNC 27599-3290USA

Bottom-up synthesis of semiconductor nanowires(NWs)by the vapor-liquid-solid(VLS)mechanism has enabled diverse technological applications for these *** metallic NWs,however,it has been challenging to form large-area interconnected NW ***,we generate centimeter-scale meshes of mechanically and electrically interconnected Si NWs by sequentially growing,collapsing,and joining the NWs using a capillarity-driven welding *** fabricate meshes from VLS-grown NWs ranging in diameter from 20 to 100 nm and find that the meshes are three-dimensional with a thickness ranging from^1 to^10 microns depending on the NW *** extinction measurements reveal that the networks are semi-transparent with a color that depends on the absorption and scattering characteristics of individual ***,active voltage contrast imaging of both centimeter-and micron-scale meshes reveals widespread electrical *** a sacrificial layer,we demonstrate that the mesh can be liberated from the growth substrate,yielding a highly flexible and transparent *** transport measurements both on the growth substrate and on liberated,flexible films reveal electrical conduction across a centimeter scale with a sheet resistance of^160-180 kΩ/square that does not change significantly upon *** the ability to encode complex functionality in semiconductor NWs through the VLS process,we believe these meshes of networked NWs could find application as neuromorphic memory,electrode scaffolds,and bioelectronic interfaces.

关键词： semiconductor nanowire conductive network flexible electronics welding thermal annealing active-voltage contrast

Trends of Population Growth in China:Maximum Number Will Exceed 1.5 Billion

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China Population Today 1996年第1期13卷 16-17页

作者： f Lin j Liu

ＴｒｅｎｄｓｏｆＰｏｐｕｌａｔｉｏｎＧｒｏｗｔｈｉｎＣｈｉｎａ：ＭａｘｉｍｕｍＮｕｍｂｅｒＷｉｌｌＥｘｃｅｅｄ１．５ＢｉｌｌｉｏｎⅠ．ＴｈｅＴｒｅｎｄｏｆＣｈｉｎａ＇ｓＰｏｐｕｌａｔｉｏｎＧｒｏｗｔｈａｔａＬｏｗＦｅ... 详细信息

ＴｒｅｎｄｓｏｆＰｏｐｕｌａｔｉｏｎＧｒｏｗｔｈｉｎＣｈｉｎａ：ＭａｘｉｍｕｍＮｕｍｂｅｒＷｉｌｌＥｘｃｅｅｄ１．５ＢｉｌｌｉｏｎⅠ．ＴｈｅＴｒｅｎｄｏｆＣｈｉｎａ＇ｓＰｏｐｕｌａｔｉｏｎＧｒｏｗｔｈａｔａＬｏｗＦｅｒｔｉｌｉｔｙＲａｔｅＴｈｅｍｏｓ...

关键词： Trends of Population Growth in China

Thermoluminescence characterization of natural and synthetic irradiated Ce-monazites

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journal of Rare Earths 2024年第4期42卷 643-650页

作者： V.Correcher C.Boronat j.Garcia-Guinea j.f.Benavente T.Rivera-Montalvo CIEMAT Av.Complutense 4028040MadridSpain MNCN-CSIC J.Gutierrez Abascal 228006MadridSpain Instituto Politécnico Nacional CICATA-IPNAv.Legaria 694Mexico City11500Mexico

The thermoluminescence(TL)emission of synthetic and natural Ce-monazites was characterized here to determine the potential application in the identification of microscopic defects from a qualitative point of view trying to link each TL peak to a chemical-physical *** kinetic parameters that lead the luminescence processes were calculated by means of variable heating rate and computing glow curve deconvolution methods and allow identifying three groups of components at~90,130 and 290℃(for the mineral sample)and~90,170,220,270 and 320℃(for the synthetic CePO_(4):Nd_(0.20),La_(0.25)).The main differences appreciated in these complex TL curves are mainly due to(i)the content of impurities(natural sample contains lanthanides as well as U 0.60%and Th 5.22%)and(ii)the degree of crystallinity of the samples which is directly related to the type of impurities(synthetic monazite relies only on Nd and La).The behavior of the dose response in the range of 1-8 Gy is similar for both samples;the TL intensity increases linearly as the dose increases without changes in the position of the maxima,denoting first-order kinetic luminescence *** peak could be mostly associated with structural defects(i.e.,phase transitions),chemical reactions(i.e.,Ce3+?Ce4+redox reaction,dehydration or dehydroxylation processes)or intrinsic defects(i.e.,frenkel defects,ODCs or NBOHCs).

关键词： Thermoluminescence Kineticparameters Phosphate Ce-monazite Defects Rare earths

Modelling Impact of Dredging and Dumping in Ebb-flood Channel Systems

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Transactions of Tianjin University 2008年第4期14卷 271-281页

作者： HIBMA A WANG Z B STIVE M j f Vriend H j de Delft University of Technology P O Box 5048 2600 GA Delft the Netherlands

for a channel-shoal system in a funnel-shaped basin the impact of dredging and dumping is investigated using a complex process-based model. first, the residual flow and sediment transport circulations are analysed for the channel-shoal pattern, which has emerged after a longterm model simulation. Results are compared to the Western Scheldt estuary, which forms the inspiration for this study. Subsequently, different dredge and dump scenarios are modelled, according to a conceptual model, in which ebb- and flood-channels and enclosed shoals form morphodynamic units (cells) with their own sediment circulation. Model results show that dumping sediment in a channel further reduces the channel depth and induces erosion in the opposite channel, which enhances tilting of the cross-section of the cell and eventually can lead to the degeneration of a multiple channel system into a single channel. The impact of different dredging and dumping cases agrees with results from a stability analysis. This means that this type of model applied to a realistic geometry can potentially be used for better prediction of the impact of human interventions.

关键词： estuaries morphology numerical model channel shoal dredging dumping

Inhibition of Electromigration in Eutectic SnBi Solder Interconnect by Plastic Prestraining

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journal of Materials Science & Technology 2011年第11期27卷 1072-1076页

作者： X.f. Zhang H.Y. Liu j.D. Guo 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

Plastic prestraining was applied to a solder interconnect to introduce internal defects such as dislocations in order to investigate the interaction of dislocations with electromigration damage. Above a critical prestrain, Bi interfacial segregation to the anode, a clear indication of electromigration damage in SnBi solder inter- connect, was effectively prevented. Such an inhibiting effect is apparently contrary to the common notion that dislocations often act as fast diffusion paths. It is suggested that the dislocations introduced by plastic prestraining acted as sinks for vacancies in the early stage of the electromigration process, but as the vacancies accumulated at the dislocations, climb of those dislocations prompted recovery of the deformed samples under current stressing, greatly decreasing the density of dislocation and vacancy in the solder, leading to slower diffusion of Bi atoms.

关键词： Electromigration Interfacial segregation Prestrain Dislocation Vacancy

ELECTROCHEMICAL fEATURES DURING PITTING CORROSION Of LY12 ALUMINUM ALLOY IN DIffERENT NEUTRAL SOLUTIONS

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Acta Metallurgica Sinica(English Letters) 2003年第4期16卷 319-326页

作者： Y.L.Cheng j.f.Li j.Q.Zhang C.N.Cao f.H.Cao Z.Zhanq DepartmentofChemistry YuquanCampusZhejiangUniversityHangzhou310027.China StateKeyLaboratoryforCorrosionandProtectionofMetals InstituteofMetalResearch.TheChineseAcademyofSciencesShenyang110016ChinaManuscriptreceived10July2002 inrevisedform10October2002

The electrochemical features of commercial airfrarne material, Al alloy LY12, in 0.349mol/L neutral sodium chloride (NaCl) and sodium sulfate (NazSO^) solutions were investigated by electrochemical impedance spectroscopy (EIS) and potentiody-namic polarization techniques. The microstructure of the as-tested samples was studied by scanning electron microscopy. The results show that the Nyquist plots of LY12 at different immersion time displayed different features, indicating that the Cl- ions elevate the corrosion rate and inhibit the repassivation of a metastable pit. It also shows that the corrosion product of LY12 formed in SO42- solution isn't easy to dissolve, and it will cover the surface of working electrode in the electrolyte. SEM images indicate that the corrosion apparent area and pit number of LY12 in NaCl solution are greater than that in Na2SO4 solution.

关键词： LY12 aluminum alloy pitting corrosion electrochemical impedance spectroscopy potentiodynamic polarization pit- morphology

Soil Organic Carbon Pools Under Switchgrass Grown as a Bioenergy Crop Compared to Other Conventional Crops

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Pedosphere 2013年第4期23卷 409-416页

作者： f.G.DOU f.M.HONS W.R.OCUMPAUGH j.C.READ M.A.HUSSEY j.P.MUIR Texas A&M AgriLife Research &Extension Center at Beaumont Department of Soil and Crop Sciences Texas A&M University Texas A&M AgriLife Research Station at Beeville Texas A&M AgriLife Research and Extension Center at Dallas Texas A&M AgriLife Research and Extension Center at Stephenville

Switchgrass （Panicum virgaturn L.） has been proposed as a sustainable bioenergy crop because of its high yield potential, adap- tation to marginal sites, and tolerance to water and nutrient limitations. A better understanding of the potential effects of biomass energy crop production practices on soil biological properties and organic matter dynamics is critical to its production. Our objective was to evaluate changes in C pools under a warm-season perennial switchgrass in different soils compared to typically-grown crops col- lected at College Station, Dallas, and Stephenville, TX in february 2001. Sampling depths were 0-5, 5-15, and 15-30 cm. Switchgrass increased soil organic C （SOC）, soil microbial biomass C （SMBC）, mineralizable C, and particulate organic matter C （POM-C） com- pared to conventional cropping systems. Soil C concentrations were in the order： long-term coastal bermudagrass [Cynodon dactylon （L.） Pers.] 〉 switchgrass or kleingrass （Panicum coloratura L.） planted in 1992 〉 switchgrass 1997 〉 conventional cropping systems. Soil C concentrations tended to increase with increasing clay content. Greater microbial biomass C followed the order of Dallas 〉 College Station 〉 Stephenville, and ranged from approximately 180 mg C kg-1 soil at Stephenville to 1 900 mg C kg-1 soil at Dallas. Particulate organic C was more sensitive than other fractions to management, increasing as much as 6-fold under long-term coastal bermudagrass compared to conventional cropping systems. Our study indicated that conversion of conventional cropping systems into switchgrass production can sequestrate more SOC and improve soil biological properties in the southern USA.

关键词： cropping systems particulate organic C perennial grasses soil microbial biomass C soil mineralizable C

Time-Harmonic Acoustic Scattering in a Complex flow:A full Coupling Between Acoustics and Hydrodynamics

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Communications in Computational Physics 2012年第2期11卷 555-572页

作者： ***-Ben Dhia j.f.Mercier f.Millot *** E.Peynaud POEMS CNRS-INRIA-ENSTA UMR 723132 Boulevard Victor75015 ParisFrance CERfACS 42Avenue Gaspard Coriolis31057 Toulouse Cedex 01France

for the numerical simulation of time harmonic acoustic scattering in a complex geometry,in presence of an arbitrary mean flow,the main difficulty is the coexistence and the coupling of two very different phenomena:acoustic propagation and convection of *** consider a linearized formulation coupling an augmented Galbrun equation(for the perturbation of displacement)with a time harmonic convection equation(for the vortices).We first establish the well-posedness of this time harmonic convection equation in the appropriatemathematical *** the complete problem,with Perfectly Matched Layers at the artificial boundaries,is proved to be coercive+compact,and a hybrid numerical method for the solution is proposed,coupling finite elements for the Galbrun equation and a Discontinuous Galerkin scheme for the convection *** a 2D numerical result shows the efficiency of the method.

关键词： Aeroacoustics scattering of sound in flows Galbrun equation advection equation finite elements discontinuous Galerkin method

Ultrafine Grained HSLA Steels for Cold forming

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journal of Iron and Steel Research International 2010年第10期17卷 50-56页

作者： R González j O García M A Barbés M j Quintana L f Verdeja j I Verdeja School of Engineering Panamerican University ETSIMO Oviedo University

The industrial level production of ultrafine grained （or ultrafine ferrite） ferrous alloys was investigated through three examples of steels that complied with the EN 10149-2 Euronorm and were produced by advanced con- trolled hot rolling techniques. The steel samples were tension tested and chemically analyzed, and the microstructure was evaluated through quantitative metallographic techniques to determine parameters such as yield stress, amount of microalloying elements, strain hardening coefficient, grain size, and grain size distribution. These steels were micro- alloyed with Ti, Nb, and Mn with ASTM grain sizes of approximately 13--15. The careful control of chemical com- position and deformation during production, giving a specific attention to the deformation sequences, austenite non- reerystallization temperatures and allotropic transformations during cooling, are indispensable to obtain steels with an adequate strain hardening coefficient that allows cold working operations such as bending, stretching or drawing.

关键词： ultrafine steel metallography strain hardening Euronorm