简介:ChloridecontentandthepHvalueoftheporesolutionintheneighborhoodofsteelreinforcementaredecisiveparametersforinitiationandrateofcorrosion.Theporesolutionofcementmortarandhardenedcementpastehasbeenexpressedfromtheporespacebyhighpressureintheinvestigation.Theinfluenceofthewater-cementratio,age,andadditionofchloridetothefreshmixonchloridecontentintheporesolutionhasbeendeterminedbyionchromatography.AtthesametimethepHvalueoftheporesolutionhasbeendetermined.Thedissolvedchloridecontentdecreaseswithincreaseinthewater-cementratio.Theamountofboundchlorideincreaseswithtime,butitdecreaseswithdecreasingcontentofdissolvedchlorideintheporesolution.Asignificantinfluenceofcarbonationonthedissolvedchloridecontentoftheporesolutionhasbeenobserved.Withcompletecarbonation,thedissolvedchloridecontentincementmortarandhardenedcementpasteincreasesbyafactorbetween2and12.Theboundchloridedecreasesby27%-4%.Asexpected,thepHvaluedecreasesfromaround13.2toaslowas8.0duetocarbonation.ItcanbeconcludedthatcarbonationnotonlylowersthepHvaluebutliberatesboundchloride.Thisisoneobviousreasonwhythecombinedactionofchloridepenetrationandcarbonationacceleratessteelcorrosionandshortenstheservicelifeofreinforcedconcretestructures.
简介:Anewfuellingmethod,thesupersonicmolecularbeaminjection(SMBI)systemhasbeenappliedtoW7-ASinMay2001,supportedbytheNationalNatureScienceFoundationofChinaandtheMax-PlanckInstituteofPlasmaPhysics,Garching,Germany.TheexperimentswithhydrogenordeuteriumonW7-ASwereimplementedfortwoyears.
简介:TheformationmechanismfortheoctahedralcentralstructureoftheHe7^+clusterisproposedanditstotalenergycurveiscalculatedbythemethodofamodifiedarrangementchannelquantummechanics(MACQM).TheenergyisafunctionofseparationRbetweentwonucleiatthecenterandanapexoftheoctahedralcentralstructure.TheresultofthecalculationshowsthatthecurvehasaminimMenergy-19.7296a.u.atR=2.40α0.ThebindingenergyofHe7^+withrespecttoHe^++6Hewascalculatedtobe0.6437a.u.ThismeansthatthedusterofHe7^+maybeformedinthestableoctahedralcentralstructurewithR=2.40α0.
简介:在相同的反应体系中当ph值从约9.5调变至11时分别合成出双中孔SiO2和六方中孔SiO2材料,并用XRD、N2吸附、TEM、TG/DTA和FTIR等测试手段对合成产物进行了表征。实验结果表明,双中孔SiO和六方中孔SiO2是合成中必然出现的两种不同的中孔物相。与六方中孔SiO2相比,双中孔SiO2也具有典型中孔材料的特征XRD谱图,虽然仅呈现一个易让人产生不完全晶化误解的相对较宽的单XRD衍射峰(d=5.2nm),但它却给出一种独特的N2吸附等温线和窄的双峰中孔孔径分布曲线。由于孔壁的无定形及表面活性剂分子与SiO2骨架间相似的相互作用,两类材料给出类似的FTIR谱图和TG/DTA曲线。然而,在双中孔SiO2的FTIR谱图中960cm处峰强度的微小变化可能意味着在锻烧脱除模板剂后双中孔SiO2较六方中孔SiO2具有更高的骨架聚合度。更多还原
简介:Atacertainhightemperature,thiscyclewillbedominantandendtherp-processtoheavierregion[2].Itprovidesanuppertemperaturelimitforrp-processalongtheprotondriplinetoproducenuclidesbeyondA=84,includingthelightpnuclidesof92;94Mo,96;94Ru.TheexistenceofZr-Nbcycleisanimportantquestioninrp-process[2].α-separationenergy(Sα)of84Moplaysanimportantroleintheformationofthiscycle.Astrongenhancementof83Nb(p,α)reactionrateisduetoaverylowSαof84Mo[1].
简介:Veryrecently,BelleannouncedtheirobservationofΥ(5S)!bJ!(J=0;1;2),indicatingthattheΥ(5S)!bJ!decaysalsohavelargedecaywidths,i.e.,themeasuredbranchratiosofΥ(5S)!bJ!are<3:410??3,(1:640:23+0:30??0:22)10??3,and(0:570:220:07)10??3withJ=0;1;2,respectively[1].ItshouldbenoticedthateventhoughthetreelevelcontributionstoΥ(5S)!bJ!(J=0;1;2)shouldbestronglysuppressedduetotheOkubo-Zweig-Iizuka(OZI)rule,suchlargedecaywidthsareobserved,whichagaininspiresourinterestinunderstandingsuchquantities.Inthiswork,weproposethatthecontributionfromthehadronicloopshouldbeconsideredinstudyingΥ(5S)!bJ!.
简介:Fourkeyreactions,12C(,)13O,13C(,n)16O,25Mg(p,)26Aland19F(p,)16O,willbestudiedforthefirsttimewithinorneartheastrophysicalrelevantenergyregions(Gamowwindow)atJinpingUndergroundlaboratoryforNuclearAstrophysics(JUNA)[1],whichwilltaketheadvantageoftheultra-lowbackgroundofChinaJinPingundergroundLaboratory(CJPL),highcurrentacceleratorbasedonECRsourceandahighlysensitivedetectionsystem.