学科分类
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128 个结果
  • 简介:Lanthanumchlorideα-D-ribopyranosepentahydratecomplexwaspreparedandspeculateditsstructurefromthesimilarIRspectraofcorrespondingpraseodymiumandneodymium-D-ribosecomplexes,whichrevealthecoordinationbehaviorofD-ribosetolanthanideionsandgiveusamodeloftheinteractionsbetweenmetalionsandcarbohydrates.

  • 标签: 金属离子 交互作用 碳水化合物 氯化稀土 吡喃核糖 FT-IR
  • 简介:Experimentaldataofhydrolyticpolymerizationoflanthanideionsinaqueoussolutionweretreatedbygraphicmethod,computerfittingandpqanalysis,speciespresentwereascertainedandhydrolysisconstantsobtained.Ln(OH)2+andLn2(OH)24+predominatedinthespeciesofallhydroly-sisproducts.Whenthefirstandthesecondhydrolysisconstantswereplottedagainstradiiandef-fectivenuclearchargeoflanthanideions,thecurvesobtainedconformedwiththe“three-divisiongroups”rule.CorrelationbetweenhydrolysisconstantsofLn2(OH)24+andotherhydrolysisconstantsislinear.Usingtheaboveempiricalcorrelationswecalculatedhydrolysisconstantsofalllanthanideionsandobtainedsatisfactoryresultswhichshowedgoodregularityforhydrolysisoflanthanideionsandthussystematizedalldataofthereaction.

  • 标签: HYDROLYSIS CONSTANTS POLYMERIZATION satisfactory LANTHANIDE REGULARITY
  • 简介:TheeffectofCdionsonsalmonspermDNAwasstudiedbymeansofcirculardichroism(CD),Ramanspectroscopy,X-rayphotoelectronspectroscopy(XPS)andfluorescencespectroscopy.TheCDspectralandfluorescentprobe-acriflavineresultsindicatethattheDNAunderwentaconformationchangeupontheadditionofCdions.XPSandRamanstudiesrevealthatthereexistedinteractionsbetweenCdionsandthephosphategroupsoftheDNA.Inaddition,anewbandappearedat803cm-1intheRamanspectra,whichcanbeattributedtocharacterizing"marker"bandofA-DNA.ItisconcludedthatCdionscanbecoordinatedbythephosphategroupsoftheDNAandinducetheconformationchangesoftheDNAfromB-DNAtoA-DNA.

  • 标签: CD ion DNA RAMAN spectroscopy Conformation.
  • 简介:TheinteractionsbetweenmetalionssuchasZn2+,Pb2+,Mn2+,Hg2+,Cd2+,Ni2+andchitosanhavebeeninvestigatedusingthemodelclustermodelmethodanddensityfunctionalmethod.FulloptimizationandfrequencyanalysisofallclustermodelshavebeenperformedemployingB3LYPhybridmethodat3-21Gbasissetlevelexceptmetalionswhichwereinvokedtouseeffectivecorepotential(ECP)method.Theenergychanges,andthemainstructuralparametershavebeenobtainedduringthetheoreticalstudyoftheadsorptionofmetalionsonthechitosan.Thecalculationsshowedthatthecoordinationmodesofmetalionswithchitosanmodelsweredifferent,thegeometriesofMn2+,Zn2+,Cd2+,Hg2+,Pb2+ionscoordinatedwithtwonitrogenatomsandtwooxygenatomsweredistortedtetrahedral,whilethesquareplanarstructureofNi2+coordinatedtwonitrogenatomsandtwooxygenatomswasobserved.Theheatofreactionbetweensixmetalionsandchitosanmodelsshowedtheorder:Mn2+>Ni2+>Zn2+>Pb2+>Hg2+>Cd2+,thissuggestedthatthecoordinationstrengthofMn2+>Ni2+>Zn2+>Pb2+>Hg2+>Cd2+.

  • 标签: 壳聚糖 金属离子 吸附 密度函数理论 基组
  • 简介:在2006年5月,高紧张野火在Daxing'an山发生在Songling森林区域,中国。八个离子的集中变化(K[+],Na[+],Ca[2+],Mg[2+],Cl,Br,NO3;SO4[2])被测量在烧;在到2006年10月的从5月的火以后的未燃的溪流。大多数离子流动是更高的在的结果表演在采样时期期间在未燃的溪流比那烧了溪流,;从烧的溪流搬运的大多数离子的最大的集中发生在7月。在火以后,大多数振幅化学药品离子是Ca[2+],谁的平均集中,是5.50mg·L[1]比那高在里面未燃的溪流,;每个化学离子的全部的集中介绍趋势Ca[2+]>SO4[2]>Na[+]>Mg[2+]>NO3。Ca的平均集中[2+],SO4[2],Na[+],Mg[2+],NO3显示出K的一个增加趋势,而是那些[+],Cl,Br有一个减少的趋势。SO4[2]在这些阴离子之中有最大的损失,由NO3列在后面。总的来说,阳离子的增加度比在烧以后的阴离子的大。

  • 标签: 森林防火 河流 水质量 养分 射击效果
  • 简介:40Ca+离子的平均动能被在一个rf离子陷井蒸发离子的方法测量。离子40Ca+的动能与从10改变缓冲区气体压力从0.5eV变化到0.2eV[?]7mbar到10[?]5mbar。Brownian运动模型也被介绍计算套住的离子的平均动能。[从作者抽象]

  • 标签: 囚禁离子 动能 气体冷却 缓冲 射频离子阱 气体压力
  • 简介:Metalion-imprintedlycrosslinkedchitosanresin1andresin2werepreparedbytheuseofCu^2+andNi^2+astemplateionsandglutaraldehydeascrosslinkingagent,respectively,ThroughinvestigationontheadsorptioncapactiesandbindingconstantsforCu^2+,Ni^2+andCo^2+ionsonchitosanresins,resin1andresin2exhibittheadsorptionselectivityforthemixturesolutionof1L1Cu^2+andNi^2+ions.Theadsorptionselectivityofmetalion-imprintedresinsfortheirtemplateionsinmuchhigherthanthatofuncrosslinkedchitosanresin.

  • 标签: 金属离子分离 脱乙酰壳多糖合成树脂 吸附选择性
  • 简介:Thestiffnessandstrengthofextracellular(EC)regionofcadherinareproposedtobetwoimportantmechanicalpropertiesbothforcadherinasamechanotransductorandfortheformationofcell-celladhesion.Inthisstudy,wequantitativelycharacterizedthestiffnessandstrengthofECstructurewhenitbindswithdifferenttypesofionsbymoleculardynamicssimulations.ResultsshowthatECstructureexhibitsarod-likeshapewithhighstiffnessandstrengthwhenitbindswiththebivalentionsofcalciumormagnesium.However,itswitchestoasoftandcollapsedconformationwhenitbindswiththemonovalentionsofsodiumorpotassium.ThisstudyshedslightontheimportantroleofthebivalentionsofcalciuminthephysiologicalfunctionofEC.

  • 标签: 二价离子 钙粘蛋白 强度 刚度 分子动力学模拟 量化
  • 简介:Inordertostudytheeffectoftheparameterssuchastheenergydensityandthegasvelocityonthetransportrateofions,theappliedforceandthemotionlawofchargedparticlesintheelectricfieldofcoronadischargesatatmosphericpressureisinvestigatedinthispaper.Asaresult,whenthegasvelocityisraisedfrom1.5m/sto25m/sforanenergydensityof0.4mJ/cm~3,theionictransportrateincreasesfrom5.4×10~8/cm~3.sto8×10~(10)/cm~3.s,whichisanincreaseofovertwoordersofmagnitude.However,inthe-zonesof-streamerandglowdischarges,theeffectoftheinputehergydensityandtheenergydensityofgasionizationonthetransportrateisbelowoneorderofmagnitude.Inconclusion,theincreaseofchargedparticlemomentumcanbeamajorfactorinraisingthetransportrateandreducingthevolumeoftheplasmasources.

  • 标签: 等离子体物理 离子转移率 能量密度 电晕放电 大气压 气体速度
  • 简介:IsotopicDistributionsofHafniumfromInteractionofHeavyionswithnatW¥ZhangXiang;LiWenxin;SunTongyu;YinXinmin;QinZhi;...

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  • 简介:Thereexistsauniversalphenomenathatsodiumionsareleakedfromthestrongbasicanionexdchangerinoperation,whichhasbeenpuzzlingtheresearchersworkinginthefieldofwatertreatmentforyears.Itiswellknownthattheleakageofsodiumionswillseriouslyaffectthepruityofeffluent.Onthebasisoflotsoflaboratoryandindustrialexperiments,themechanismofthesodiumionsleakedfromananionexchangerhasbeenpreliminarilymadeoutandsomenewchemicalreactionequationsaswellassomeimprovingmeasureshavebeenputforwardinthisarticle.

  • 标签: 钠离子 反应机理 强碱 阴离子交换剂
  • 简介:<正>1IntroductionAlkalinelakesarewidelydistributedintheareaoftheQinghai-TibetPlateau.Mostofthesaltlakesarefamousfortheirhighconcentrationoflithium,potassium,magnesium,boron(Ma,2000).Inrecentyears,asanewenergymaterial,lithiumanditscompoundsarewidelyusedinthenewarea,suchasaerospaceindustry,nuclear

  • 标签: LITHIUM magnesium BORON Plateau POTASSIUM aerospace
  • 简介:三3,3-di(4-substituted-phenyl)-1,1-isophthaloylbis(thiourea)混合物作为新奇中立阴离子受体被设计,并且在好收益由简单步骤综合了。受体1的单个晶体结构证明一个溶剂分子被主人分子通过分子间的氢结合捕获。而且,它作为为存在的一个超分子的系统自我装配丰富内部--并且intramolecular氢结合并且-在苯基组之间的相互作用。他们阴离子受体被检验了由的申请紫外力并且1HNMR光谱学,证明他们比另外的卤化物为氟化物有一种更高的选择。主人和客人在第一个步骤通过氢结合相互作用形成了1:1stoichiometry建筑群,然后在F的过量的存在跟随deprotonation的一个过程吗?在DMF的溶剂。

  • 标签: 硫脲 钳型阴离子受体 合成 氟化物离子 选择性识别