简介:Afewadditionaldatafromourpreviousexperimentswereplottedtoemphasizetheshear-thickeningbehaviorofdeoxysickleerythrocyte(SS)suspension.Aconstitutiveequation(namedasFXequation)wasdevelopedandappliedtoacylindricalpipeflowofashear-thickeningfluid.Abluntvelocityprofileanditsvolumeflowratewerecalculated.Theflowwasnon-viscous(potential)inthecentralpartofthepipe(i.e.thecentralcoreorthecentralplug-flow),andbecamemoreandmoreviscoustowardsthewallofthepipeafteraspecificradialdistance,whichwasdeterminedbyacriticalshearrateofγF(namedasFung'sshearrate).Furthermore,combiningtheFXequationwiththeoriginalCasson'sequation,theauthorobtainedamodifiedCasson'sequationbyintroducingγF.
简介:Whenanaircraftishoveringordoingadive-hikeflightatafixedspeed,aconstantadditionalinertialforcewillbeinducedtotherotorsystemoftheaero-engine,whichcanbecalledaconstantmaneuverload.Takehoveringasanexample.AJeffcottrotorsystemwithabiasedrotorandseveralnonlinearelasticsupportsismodeled,andthevibrationcharacteristicsoftherotorsystemunderaconstantmaneuverloadareanalyticallystudied.Byusingthemultiple-scalemethod,thedifferentialequationsofthesystemaresolved,andthebifurcationequationsareobtained.Then,thebifurcationsofthesystemareanalyzedbyusingthesingularitytheoryforthetwovariables.IntheEG-plane,whereEreferstotheeccentricityoftherotorandGrepresentstheconstantmaneuverload,twohysteresispointsetsandonedoublelimitpointsetareobtained.Thebifurcationdiagramsarealsoplotted.Itisindicatedthattheresonanceregionsofthetwovariableswillshifttotherightwhentheaircraftismaneuvering.Furthermore,themovementalongthehorizontaldirectionisfasterthanthatalongtheverticaldirection.Thus,thedifferentoverlappingmodesofthetworesonanceregionswillbringaboutdifferentbifurcationmodesduetothenonlinearcouplingeffects.Thisresultlaysatheoreticalfoundationforcontrollingthestabilityoftheaero-engine’srotorsystemunderamaneuverload.
简介:Wavepropagationanalysisforafunctionallygradednanobeamwithrectangularcross-sectionrestingonvisco-Pasternak'sfoundationisstudiedinthispaper.Timoshenko'sbeammodelandnonlocalelasticitytheoryareemployedforformulationoftheproblem.TheequationsofmotionarederivedusingHamilton'sprincipalsbycalculatingkineticenergy,strainenergyandworkduetoviscoelasticfoundation.Theeffectsofvariousparameterssuchaswavenumber,non-homogeneousindex,nonlocalparameterandthreeparametersoffoundationareperformedonthephasevelocityofthenanobeam.Theobtainedresultsindicatethatsomeparameterssuchasnon-homogeneousindex,nonlocalparameterandwavenumberhavesignificanteffectontheresponseofthesystem.
简介:Fourkeyreactions,12C(,)13O,13C(,n)16O,25Mg(p,)26Aland19F(p,)16O,willbestudiedforthefirsttimewithinorneartheastrophysicalrelevantenergyregions(Gamowwindow)atJinpingUndergroundlaboratoryforNuclearAstrophysics(JUNA)[1],whichwilltaketheadvantageoftheultra-lowbackgroundofChinaJinPingundergroundLaboratory(CJPL),highcurrentacceleratorbasedonECRsourceandahighlysensitivedetectionsystem.
简介:Thispaperreportstwolanthanidecomplexesofformula(C9H7)Ln(C8H8)·(THF)2whereLnisProrNd,C9H7isindenyl,andC8H8iscyclooctatetraene(COT).ThecomplexeswerepreparedbythereactionofLnCl3withK(C9H7)andK2(C8H8)inTHF.(C9H7)Pr(C8H8)·(THF)2crystallizesinTHFat-15℃inthemonoclinicspacegroupP21:withunitcelldimensionsa=8.446(0),b=10.083(2),c=13.407(3),β=105.48(1)°,V=1100.43(35)3,Dc=1.52g/cm3andZ=2.ThefinalRvalueis0.033,Rwvalueis0.030,respectively.In(C9H7)Pr(C8H8)·(THF)2afive-memberedringcentroidofC9H7,theC8H8ringcentroidandthetwooxygenatomsfromthetwoTHFmoleculesformadistortedtetrahedralgeometryaroundthemetal.
简介:通过5-甲基-7-甲氧基异黄酮与盐酸羟胺的缩合制得中间产物4-苯基-5-(2-羟基-4-甲氧基-6-甲基苯基)异恶唑,然后经过光异构化反应合成了4-甲氧基-6-甲基-7a-苯基苯并吡喃并[2,3-b]氮丙啶-7-酮,并采用IR,NMR,HRMS和单晶X-衍射分析对其结构进行了表征.单晶X-衍射分析结果表明:标题化合物属于单斜晶系,空间群P2(1)/n.在其晶体结构中,存在着氢键及芳香堆积作用,这些作用将标题化合物分子组装成了三维网络结构.
简介:8,8′-Dibromo-6,6′,7,7′-tetramethoxy-5,5′-diisopropyl-3,3′-oxydimethylenedinaphtho[2,1-b:2′,1′-d]furan,C32H30Br2O;M.W.=670;triclinic;spacegroupP1;a=8.896(2),b=10.216(1),c=10.423(1)A,α=108.48(1),β=119.36(1),γ=99.26(1);V=723.5A3;Z=1,Dcal.=1.479g.cm-3.MoKα=28.11cm-1,F(000)=326,T=293K.Thestructurewassolvedbydirectmethodandfull-matrixleast-squaresrefinementconvergedatR=0.034for2377observedreflections.Theoxygenatominseven-memberedringexistsinadisorderedarrangement.Bothbisnaphthaleneandoxygen-containingfive-memberedringhaveplanarconformationswithdihedralangle6°,showingmarkedaromaticfeature.
简介:研究了YBaCu3O6~7超导催化剂上CO2的加氢制醇反应。考察了温度、压力和空速等条件对催化剂反应性能的影响。反应的主要产物是甲醇、CO和少量甲醚。利用XPS、XRD和AFM等技术对催化剂的结构、铜的存在状态和反应活性位进行表征发现,在反应过程中,YBa2Cu3O6~7由orthombic相转变为tetragonal相。反应活性位可能是Cu(I)物种。反应后催化剂颗粒的分散程度明显提高