学科分类
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68 个结果
  • 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:Naturalfreshwatersurfacecoatings(biofilmsandassociatedminerals),whichweredevelopedintheNanhuLake,Changchun,P.R.China,wereusedasanefficientbiosorbentfortheremovalofCd(Ⅱ)fromaqueoussolutions.ThebatchexperimentswerecarriedouttodeterminetheadsorptionpropertiesofCd(Ⅱ)ontothenaturalsurfacecoatings.TheclassicalLangmuiradsorptionisothermwasappliedtoestimatingtheequilibriumcoefficientsofCd(Ⅱ)adsorbedonthesurfacecoatings.Theresultsshowthatthemaximumadsorptioncapacityofthesurfacecoatingsis434.78μmolCd/m2(beingequalto0.17mmolCd/gofsurfacecoatingsor10.38mmolCd/gFe)andtheCd(Ⅱ)removalfromsolutionmediabythenaturalsurfacecoatingswasshowntobestronglyaffectedbysolutionpHandionstrength.TheresultedinformationalsoindicatesthatthemaximumCdremovalefficiency(CRE)wasdeterminedtobeapproximately90%atinitialCdmassconcentrationof0.1mg/L(theconcentrationlimitofCd(Ⅱ)inwastewatersfordischargeinaquaticmediainChineselegislation),andthekineticadsorptionofCd(Ⅱ)ontothesurfacecoatingsisfastwitharound70%ofthetotaladsorption-takingplacein150mininsolutionunderthecontrolledlaboratoryconditions(mineralsaltssolutionwithdefinedspeciation,ionicstrength0.05mol/L,and25℃).WiththeadvantageofhighCdadsorptioncapacity,thenaturalsurfacecoatingsappeartobeapotentiallyeffectivebiosorbentfortheremovalandrecoveryofCd(Ⅱ)frompollutedwater.

  • 标签: 废水处理 Cd(Ⅱ) 水溶液 离子迁移 生物吸附 氧化铁
  • 简介:新奇分子地印的合成nanofiber被一种简单electrospinning技术准备在哪个polyvinylbutyral(PVB)被选择为矩阵,-cyclodextrin(-CD)作为模板分子被用作功能的单体和naringin(NG)。在由hexamethylenediisocyanate(HMDI)的cross-linked以后,合成nanofiber展出了一个高特定的有约束力的能力。nanofibers的词法结构借助于红外线的光谱(红外)被学习,X光检查衍射(XRD),和扫描电子显微镜学(SEM)。没有形成阶段,CD分子同类地主要在PVBnanofiber以内被散布分开的水晶的总数。与传统的印的CD聚合物相比,有约束力的实验证明分子地印的合成nanofiber为NG显示出特定的有约束力的地点和选择有约束力的能力。没有任何损失,分子地印的nanofiber能在有约束力的能力被使用至少六次。

  • 标签: 复合纳米纤维 分子印迹 结合能力 PVB 柚皮苷 CD
  • 简介:Bothenantiomersoffluoxetineweresynthesizedinfivestepsfromethylbenzoylacetate(1)usingmicrobial-chemicalapproachwithoverallyieldsof59%and62%respectively.(S)-Enan-tiomercanbeobtainedin>99%e.e.byrestingcellofbaker’syeastandtheRformwasproducedin81%e.e.byimmobilizedGeotrichumsp.G38.

  • 标签: microbial YEAST GEOTRICHUM RESTING ASYMMETRIC steps
  • 简介:AseriesofdoubleperovskitesRSrMnFeO_6(R=La,Pr,Nd,Sm)wassynthesizedundermildhydrothermalconditions.Crystalgrowthsofthesamplesweresensitivetoalkalinity,temperature,fillingfraction,andcompositionofinitialreactionmixture.ThedesiredseriesofcompoundsbelongstotheclassofAA'BB'O_6perovskiteswitharandomdistributionofMnandFeatomsovertheB-cationsub-lattice.TheirstructuresshowthedistortedorthorhombicsymmetrywithspacegroupPnma.TheshapesandsizesofthecrystalswereanalyzedonaRigakuJSM-6700Fbyscanningelectronmicroscopy.AnalysisdonebyXPS,MssbauerspectroscopyandiodometrictitrationrevealsthatMnandFeionshave+4and+3oxidationstates,respectively.

  • 标签: 钙钛矿相 水热合成 扫描电子显微镜 表征
  • 简介:IntroductionEletrothermalvaporization(ETV)asameansofsampleintroductioninmicrowavein-ducedplasma(MIP)sourcespectrometryhasbeen...

  • 标签: ATOMIC emission SPECTROMETRY MICROWAVE plasma TORCH
  • 简介:Toexaminetheeffectivenessofirondust-zeolitecompositeasanadsorbentfortheremovalofheavymetalionsfromaqueoussolutions,theadsorptionisotherms,thekinetic,thermodynamicandoptimumconditions,suchasinitialconcentration,pH,contacttime,adsorbentdosageandcompetitiveadsorptionconditionsofheavymetalswereinvestigated.ThecharacterizationofthecompositewascharacterizedviaFTIR,SEM,XRFandXRDmethods.Kineticresultsontheremovalofheavymetalionsfromaqueoussolutionshavebeenwelldescribedbythepseudo-second-ordermodel.TheadsorptiondataforCdandNiionswerefittedwellwiththeLangmuirandFretm-dlichisothermmodels,respectively.Themaximumadsorptioncapacitiesofirondust-zeoliteforCdandNiionswereequalto78.125and76.33mg/g,respectively.Thethermodynamicparameterssuchasenthalpy,entropyandfreeenergyofadsorptionofmetalionsweredetermined.Itwasfoundthattheprocessisendothermic,favorableandspontaneous.ThecompetitiveadsorptionabilityofheavymetalionsinthebinarysystemonthecompositeshowedthatCdionshadasynergisticeffectontheadsorotionofNiandNiionshadthenegativeeffectonCdadsorption.

  • 标签: ADSORPTION ZEOLITE IRON DUST Heavy metal
  • 简介:Thenovelcomplex[K(18-C-6)]2[Cd(mnt)2][18-C-6-18-crown-6,nmt=1,2-dicyanoethene-1,2-dithiolate,C2S2-(CN)2^2-]wassynthesizedandcharacterizedbyelementalanalysis,IRspectrumandX-raydiffractionanalysis.Thecomplexdisplaystwo-dimensionalnetworkstructureof[K(18-C-6)]complexsegmentsand[Cd(nmt)2]complexsegmentbridgedbyS-K-S,S-K-NandN-K-Ninteractionsbetweenadjacent[K(18-C-6)]and[Cd(mnt)2]units.

  • 标签: 二维网络 合成 晶体结构 18-冠醚-6络合物 镉络合物 1 2-二氰基乙烯-1 2-连二硫酸镉
  • 简介:以ABS塑料为研究对象,采用微波消解法进行样品的前处理,使用电感耦合等离子体原子发射光谱(ICP-AES)法测定ABS塑料中Pb、Cd、Hg,结果表明,Pb、Cd、Hg加标回收率均在95.0%~105%,测定相对标准偏差(RSD)均小于3%,方法在缩短样品前处理时间的同时得到较高的元素消解回收率和较为理想的精密度,适用于ABS塑料中重金属含量的快速测定。

  • 标签: 微波消解 ICP-AES ABS塑料 PB Cd HG
  • 简介:借助密度泛函理论,用B3LYP和BP86方法,对一系列潜在的新型高能密度材料分子H2N5MN5H2(M=Be,Mg,Ca,Zn,和Cd)进行了理论预测研究.结果表明,这些材料分子都非常稳定,不容易分解,其中H2N5MN5H2最稳定.金属离子的配位作用对化合物的稳定起了重要作用.配体H2N5也因从金属M获得一个电子变成H2N^-离子而变得更稳定.

  • 标签: 高能密度材料 密度泛函理论 稳定性
  • 简介:通过样品处理、谱线选择、准确度和精密度实验、加标回收实验及与其它标准测定方法的比对实验,建立了电感耦合等离子体原子发射光谱(ICP-AES)法测定粗锑中As、Bi、Cd、Cu、Fe、Pb、Se7种元素的定量分析方法。实验结果表明,方法准确度高,稳定可靠,相对标准偏差(RSD,n=6)均小于3%,方法的加标回收率在95%-105%,分析结果与分光光度法、原子吸收光谱(AAS)法及原子荧光光谱(AFS)法分析结果相吻合,能够满足日常对粗锑中杂质元素含量测定的要求。

  • 标签: 粗锑 ICP-AES 定量分析