简介:
简介:CreeppropertyofsolderalloysisoneoftheimportantfactorstoaffectthereliabilityofsolderedjointsinSMT(surfacemounttechnology).Particle-enhancementisawaytoimprovethepropertiesofsolderalloysandhascausedmuchmoreattentionthanbefore.Temperaturesappliedtosolderedjointsareoneoftheprimaryfactorsofaffectingcreeppropertiesofparticleenhancementcompositesolderedjoints.Inthispapersingleshearlapcreepspecimenswitha1mm2cross-sectionalareawerefabricatedusingCuparticleenhancement63Sn37Pbbasedcompositesolderedjointsand63Sn37Pbeutecticsolderedjointstoexaminetheinfluenceoftemperatureoncreepbehaviorofsolderedjoints.ResultsindicatedthatthecreepresistanceofsolderedjointsofCuparticleenhancement63Sn37Pbbasedcompositesolderedjointwasgenerallysuperiortothatoftheconventional63Sn37Pbsolderedjoint.Atthesametime,creeprupturelifeofthecompositesolderedjointwasdeclinedwithincreasingtemperatureanddropfasterthanthatoftheconventional63Sn37Pbeutecticsolderedjoint.
简介:第三的Ni-5%Cu-5%Sn和Ni-10%Cu-10%Sn合金的液体状态undercoolability和水晶生长动力学被玻璃fluxing方法调查。在这二合金,304K的试验性的最大的undercoolings(0.18TL)和286K(0.17TL)被完成,树枝状的生长速度分别地达到39.8和25.1m/s。从进equiaxed结构的粗糙的树突的形态学的转变发生并且谷物尺寸(Ni)当undercooling增加时,显著地分阶段执行减少。格子常数和microhardness与undercooling的改进显然增加。Cu和Sn溶质内容的丰富减少树枝状的生长速度,当时提高格子常数和microhardness(Ni)阶段。
简介:VariousopticalluminescencespectroscopictechniqueswereusedtocharacterizethehighTcsuperconductorYBa2Cu3Ox.TheemissionbandsrevealthatCu3+coexistwithCu2+andCu+inthismaterial.
简介:Alginate-Cu(Ⅱ)complexbeadsormembraneswerepreparedforremovalofurea.ThemechanismofsorptionofureawasidentifiedbyUV-Visiblespectra,FT-IRspectraandFar-Infraredspectra.Thefactorsaffectingtheureasorptioncapacitywerediscussedindetail.ResultsshowedthattheAlginate-Cu(Ⅱ)complexsorbentcansorbabout60myureapergramofsorbentat37℃andtheconcentrationofureawas130mg/100mlinNa2HPO4andNaH2PO4buffersolution(pH=7.0).
简介:AnefficientprocessfortheconversionofdimethyloxalateintoethyleneglycolwithhighselectivityandhighyieldoverCu2Owasinvestigated.InsituformedCuasatruecatalyticallyactivespeciesshowedagoodcatalyticperformanceforDMOconversiontoproduceEGin95%yield.
简介:建立起HNO3-H2O2-HF体系微波消解前处理样品,利用电感耦合等离子体质谱(ICP—MS)同时测定土壤中的铬(Cr)、镍(Ni)、铜(Cu)、砷(As)、铊(Tl)、铅(Pb)6种重金属元素含量的方法。该方法的相关系数在0.9996~1.000,相对标准偏差在0.669%~3.02%,加标回收率为94.68%~115.5%,检出限为2.004~312.4ng/L,结果表明该方法满足重金属分析的要求。用建立起的方法测定了来自湖南、湖北、云南、贵州、河南、福建、辽宁7个省45个产区烟田土壤中的Cr、Ni、Cu、As、田和Pb6种重金属元素含量;与对应烟叶中的6种重金属含量相比,聚类分析结果表明不同省区间土壤中的重金属含量无明显差异,而烟叶中却差异明显。
简介:Polyacrylonitrilebeads(PAN)cysteine(CS)wassynthesizedfrompolyacrylonitrilebeads(PAN)andcysteine(CS).ThecontentofthefunctionalgroupandthepercentageconversionofthefunctionalgroupofPAN-CSpreparedundertheoptimumconditionusingresponsesurfacemethodology(RSM)forthefirstattemptwere3.22mmol/gand35.78%.ThestructurewascharacterizedbyET-IRandelementalanalysis.TheadsorptionpropertiesoftheresinforCu(Ⅱ)wereinvestigatedbybatchandcolumnexperiments.BatchadsorptionresultssuggestedthatPAN-CShadhigheradsorptioncapabilityforCu(Ⅱ)thanothermetalionsandmaximumsaturatedadsorptioncapacitywas184.7mg/g.TheresinanditsmetalcomplexeswerestudiedbyFT-IR.Furthermore,theresincanbeelutedeasilyusing1mol/LHC1.PAN-CScanprovideapotentialapplicationforselectiveremovalofcopperfromwastesolution.
简介:Reerystallizafionofcold-roUeddiscontinuousprecipitationmicrostructurewhichhasfinelaminarstructureinanAl-40%7m(atomfraction)binaryalloyisinvestigatedbyopticalmicroscopy,SEMandTEM.Itisfoundthattherearetwokindsofrecrystallizationmechanisms:continuouscoarsening(CC)anddiscontinuouscoarsening(DC).Thelattercanbedividedintocoarseningmainlydrivenbystoreddeformationenergyatcolonyboundariesandslipbandsandtheonemainlydrivenbyboundaryenergyintheareawithlittledeformation.ItisshownthattheadditionofCucanretardthenucleationofcoarseningcellsandtheirgrowth.X-RaydiffractionanalysisindicatedthemetastablephaseCuZn4transformedintoequilibriumphaseAl4Cu3Znduringtheheatingprocess.
简介:ScanningElectronMicroscopyStudiesofYBa_2Cu_3O_(7-δ)SuperconductorsShaWei(沙维)(DepartmentofCivilEngineering,TheQueen′sUniversit...
简介:
简介:在元素粉末反应制备多孔材料中,原料粉末粒度是影响其多孔结构的主要因素之一。本文通过元素粉末反应合成的方法制备Cu-Al多孔材料,研究原料粉末的粒径对Cu-Al多孔材料孔径、孔隙度、透气度和体积膨胀率等参数的影响。结果表明:Al粉粒径是影响Cu-Al多孔材料最大孔径的主要因素,材料的最大孔径dm与Al粉粒径dp之间严格遵循dm=0.48dp的线性变化规律;Cu粉粒径则对Cu-Al多孔材料最大孔径影响较小。当粉末粒径在48.5μm以上时,粉末粒径的改变对Cu-Al多孔材料的开孔隙度和总孔隙度影响不大。在实验研究范围内,Cu-Al多孔材料的体积膨胀率随粉末粒径的增大而增大;当粉末粒径很小时,Cu-Al多孔材料存在体积收缩的趋势。