简介:采用金相组织观察、力学性能测试和统计分析等手段,研究了成品退火工艺对Φ5mmTP2内螺纹铜管微观组织和力学性能影响规律。结果表明:Φ5mmTP2内螺纹铜管退火温度为470~480℃时,铜管组织细小、均匀,同时能获得较高塑性和较高强度;490~500℃时,铜管晶粒尺寸、力学性能波动大;510~520℃时,铜管组织易粗大。Φ5mmTP2内螺纹铜管在470℃退火时,晶粒尺寸随退火时间的规律变化为d=0.0008t3-0.062t^2+1.7t-1.3,保温21min时,铜管再结晶基本完成,保温时间为28~31min时,铜管组织状态和综合力学性能最佳。
简介:Anincubationstudywasperformedtoelucidateexogenousrareearthelements(RE)influencingonmicrobialbiomass,microbialecophysiologicalparameterscmic/corg,metabolicquotientqCO2andrespiratoryrateinrelationtotemporalavailabilityinpaddysoil.Sixsampleswereaddeddifferentconcentrationsbetween0and2000mg*kg-1REEsinsoil.ResultsshowthatexogenousREhaveslightstimulativeeffectsonmicrobialindicesinpaddysoilatlowconcentrationintheearlystageafteraddingRE,whilehavinginhibitoryeffectsathighconcentration.TheinhibitionisstrengthenedwithincreasingREconcentrationandisweakenedwithincreasingincubationtime.PrincipalcomponentanalysisoftheBIOLOGdataindicatesthatmicrobialcommunitystructureshavechanged,carbonsourcesconsumptionofmicroorganismsinpaddysoilbecomesmuchmorerapidafter8weeks,andunderREstress,thechangeofmicrobialcommunitystructuresisalong-termeffect.
简介:有色金属的分类很多,大约有80多种,大致按其比重、价格、在地壳中的储量及分布情况和被人们发现与使用情况的早晚等分为五大类。(1)重有色金属;指比重大于4.5的有色金属。包括铜,镍,锢,铅,锌,锑,汞,镉和铋。(2)轻有色金属;指比重小于4.5的有色金属。包括铝,镁,钙、钾、锶和钡。(3)贵金属;指在地壳中含量少,开采和提取都比较困难,对氧和其它试剂稳定,价格比一般金属贵的有色金属。包括金、银。和铂族元素。一般比重都较大,熔点较高在916—3000度,有很好的化学稳定性、优良的抗氧化性及耐腐蚀性。(4)半金属;一般指硅、硒、碲、砷和硼五种元素。其物理化学性质介于金属和非金属之间。如砷是非金属,但它能传热和导电。
简介:TheNd3+3.2%(atomfraction):KGd(WO4)2crystalwasgrownbyKyropoulosmethod.TheabsorptionspectrumandfluorescencespectrumofNd3+:KGWcrystalweremeasured.Theabsorptioncrosssectionsat808nm(0.6799×10-20cm2)werecalculated,andtheoutputwavelengthoffluorescenceis1064and1351nm.Thediode-pumpedlaserwasoperatedbothinthefree-runningandpassivelyQ-switchedoperatingmodes.Themaximumlaseroutput(1064nm)is326mWwith62.7%slopeefficiencywheninputenergyis900mW.ThebeamqualityfactorM2≈1.1.Thegreenlightof532nmisobtainedinfrequencydoublingoperation.ThelaserispassivelyQ-switchedbyusingCr4+:LuAGassaturableabsorber.Thepulsewidthis170nsatrepetitivefrequencyof15kHZ.
简介:ThispaperistodiscussthesensingcharacteristicsofSnO2semiconductorcomponentsinwhichPr6O11isadded.Whenexperimentingunder11gasesofCH3COCH3,C2H5OH.C6H5CH3,H2,NH3,CO,CO2CH4,C4H10,n—C6H14andn—C7H16,wefindthatthecomponentshaveselectivitytoCH3COCH3,C2H5OHandthattheidealamountofPr6O11inthecomponentsisaboutI.Owt%.TheexperimentsalsoshowthatwiththeincreaseoftheamountofPr6O11,theidealworkingtemperature,theresponseandrestorationtimedecrease.
简介:AninorganicnanomaterialscombinationofSm,Ag,andTiO2wassynthesizedusingsupercriticalfluiddrying(SCFD)combinedwithsol-geltechniques.Thestructure,photocatalysisandbacteriostaticactivityofthematerialswerecharacterizedbyX-raydiffraction(XRD),transmissionelectronmicroscopy(TEM),X-rayphotoelectronspectroscopy(XRPS),photocatalyticperformance,andantibacterialactivityexperiments.TheXRDresultsshowedthattheaverageparticlediameterofSm/Ag/TiO2was14.62nmandAgandSmionsweredispersedonthesurfaceofTiO2inahighlydispersed,amorphousform.TheTEMimageshowedthatthesizeoftheparticlewas12nmusingtheschererformula.TheXPSresultshowedthattheelementSmwasdopedandAgwasloadedinorganicnanomaterialssuccessfully.Sm/Ag/TiO2exhibitedoptimalphotocatalyticpropertiesat600oC,thephotocatalyticoptimalproportionofSm/Ag/TiO2was2:2:100.Whenthemolarratiowas2:2:100,thebacteriostaticcirclediameterwas16mmforStaphylococcusaureus,theminimumbacteriostaticconcentrationwas200μg/mLforwhitebeadscoccus,andtheminimumbactericidalconcentrationwas2×104μg/mLforwhitebeadscoccus.TheSEMresultsshowedthattheantibacterialmaterialattachedtothecandidaalbicanscellsurface,cellsappearedfolddeformation.ThereforetheinorganicnanomaterialsSm/Ag/TiO2hadhightemperatureresistance,goodphotocatalyticandantibacterialcharacteristicsinvisiblelight.
简介:TheeuropiumionsdopedMMoO_4(M=Sr,Ba)nanophosphorsweresuccessfullysynthesizedviaafacilehydrothermalmethodusingisopropanol.Therelationshipbetweenphosphorcrystallinephase,morphology,photoluminescentpropertiesandhexadecyltrimethylammoniumbromide(CTAB)concentration,pHvalueinprecursorsolutionwasinvestigated.TheresultsindicatedthatthemorphologyandphotoluminescentpropertieswerestronglyinfluencedbyCTABconcentrationandpHvalueinprecursorsolution.InSrMoO_4:Eu~(3+)hosts,thephosphorsurfacetendedtobecomesmootherastheconcentrationofCTABwasincreased;whileparticlestendedtoagglomerateasincreasingpHvalue.TherelativeintensityratioofchargetransferbandtoEu~(3+)characteristicemissionpeaksofMMoO_4:Eu~(3+)(M=Sr,Ba)waschangedasCTABconcentrationandpHvaluechanged.TheemissionspectraofMMoO_4:Eu~(3+)(M=Sr,Ba)couldbeadjustedbyCTABconcentrationandpHvalueduetotheirimpactsonthestructure.ItwasimportantthatthedifferentmorphologiesandphotoluminescentpropertiesofMMoO_4:Eu~(3+)(M=Sr,Ba)couldbeobtainedbythefacilehydrothermalmethodandmodulatedbychangingCTABconcentrationandpHvalue.