简介:TwonewcoenzymeB12analogues,2’,5’-dideoxycytidylcobalamin(2a)and2’,5’-dide-oxyuridinylcobalamin(2b),andtwoothers,2’,5’-dideoxyadenosylcobalamin(2c),and5’-deoxy-thymidylcobalamin(2d)werepreparedbyanimprovedmethod.AllthefouranalogueswereinvestigatedbyUV-visand2D1HNMRspectroscopy.Thecomparisonsanddiscussionabouttheirspectroscopicpropertiesweredone.
简介:Asimplemethodisappliedtocalculatingtheisotopeshifts(ISs)on5S1/2→4D3/2,5/2transitionsof87,88Sr+.FirstwehavecalculatedtheISsoflowertransitionsonaseriesofalkali-likesystemssuchasB2+,Ca+andBa+,whichareinagreementwithotherworks.ThentheISson5S1/2→4D3/2,5/2transitionsof87,88Sr+,whichareusefultostudytheSr+opticalfrequencystandard,areevaluated.
简介:Treatmentof4-amino-3-(1-aryl-5-methyl-1,2,3-triazol-4-yl)-5-mercapto-1,2,4-triazoles/2-amino-5-(1-aryl-5-methyl-1,2,3-triazole-4-yl)-1,3,4-thiadiazoleswithbenzaldehyde,acetoneandω-bromoacetophenonewastestedandcompared.ThetitlecompoundsSchiffbases,amides,imidazolo[2,1-b]-1,3,4-thiadiazolesand7H-s-triazolo[3,4-b]-1,3,4-thiadiazineshavebeenconfirmedbyelementalanalyses,^1HNMR,IRandMSspectra.AllthecompoundshavealsobeenscreenedfortheirantibacterialactivitiesagainstB.subtilis,S.aureusandE.coli.
简介:ZrO_2-SnO_2-TiO_2(ZST)系统陶艺的微波电介质性质作为Sb_2O_5掺杂物的数量的功能被学习。与0-0的增加。5%Sb_2O_5(臼齿的比率),有Sb~(5+)离子的Ti~(4+)离子的替换减少了sintering温度并且由于氧空缺的减小增加了优秀因素Q。当Sb~(5+)的数量进一步增加了时(超过0.5%)。Q被增加电子浓度减少。当与0.5%Sb_2O_5做的系统是在为6h的1150℃的sintered时,相对的绝缘的经常的ε,Qf_0,和反响的频率(TCF)的温度系数是38.46,44500GHz,20.0x10~(-6)/℃,分别地,在6GHz。
简介:1绪论PRINCE2是一种长期以来公认的项目管理方法,在英国公共部门广泛应用,在私营企业界也发展成为事实上的应用方法。PRINCE2开发于1989年,是一种结构性的项目管理方法,其所有者英国商务部(OGC)根据使用者的反馈与调查不断地对其进行完善。PRINCE2最初是为IT行业开发的,现在已发展成为通用于各种大小、各个领域的项目的管理方法。PRINCE2在全球闻名并得以广泛应用。PRINCE2手册被译成多种语言。PRINCE2的使用是免费的;虽然名称和内容受版权保护,用户可在他们的项目中参考使用该方法,而不必局限于特定的咨询师及相关的服务。
简介:ThecrystalstructureofDi-nitratobis(ethylcaprolactam)uranyl(Ⅱ)UO2[CH2(CH2)4CONC2H5]2(NO3)2wasestablishedbyasingle-crystalX-raydiffractionstudy.Itistriclinie,spacegroupP1,witha=7.171(2),b=8.655(3),c=10.182(5)A,α=78.27(3),β=70.63(3),γ=81.76(3)°,V=581.7(4)A3,Z=l,Dc=1.94g.cm-3.FinalRvalueis0.0218.Theresultrevealsthaturanylioniscoordinatedtosixoxygenatoms,twoofthemarefromtwocarbonylgroupsofethylcaprolactamandtheotherfourarefromtwonitrategroups.
简介:Halfsandwichirondicarbonylcomplex[η5-C5H3(t-Bu)2]Fe(CO)2Cl(1)reactswith1,2-dilithiumdiselenocarboraneLi2Se2C2B10H10(2)togiveabinuclearironcarboranecomplex[η5-C5H3(t-Bu)2]2Fe2(CO)3*Se2C2B10H10(3).TheX-raydiffractionanalysisofcomplex3revealsthatoneoftheironatomsischiral.
简介::Twonovelpoly[(3-alkyhhiophene-2,5-diyl)-(benzylidenequinomethane-2,5-diyl)s]derivatives,poly[(3-butylthiophene-2,5-diyl)-(p-N,N-dimethylamino)benzylidenequinomethane-2,5-diyl)](PBTDMABQ)andpoly[-(3-octylthiophene2,5-diyl)-(p-N,N-dimethylamino)benzylidenequinomethane-2,5-diyl)](POTDMABQ),weresynthesized.Thebandgapsofthetwopolymersarecalculatedas1.75eVforPBTDMABQand1.69eVforPOTDMABQ,respectively.Thehomogenousfilmsofthetwopolymerswerepreparedandtheirthird-ordernonlinearopticalpropertieswerestudiedbythebackwarddegeneratefour-wavemixingat532nm.Byusingtherelativemeasurementtechnique,thethird-ordernonlinearopticalsusceptibilitiesofPBTDMABQandPOTDMABQarecalculatedas5.62×10^-9and1.22×10^-8ESU,respectively.Itisfoundthatsubstitutedalkygroupshavestrongeffectsonthebandgapandnonlinearopticalpropertiesofthetwopolymers.Therelativelybigthird-ordernonlinearopticalsusceptibilitiesandsmallbandgapofPOTDMABQresultedmainlyfromthelongeralkylwithstrongelectron-donatingabilitycanenhancethedelocationdegreeofconjugatedπelectronics.
简介:TheepoxidationofallylchloridewithH2O2onTi-ZSM-5preparedbyisomorphoussubstitutionofHZSM-5withTiCl4gaswasstudied.TheresultsshowthatTi-ZSM-5hasahighcatalyticefficiencyfortheepoxidationofallylchloride.TheH2O2utilizationreaches99.50%whentheallylchloride/H2O2molarratiois>1.Theeffectofsolventspecies,catalystconcentration,H2O2andallylchlorideconcentrationandreactiontemperatureontheepoxidationwasinvestigatedsimultaneously.Itisfoundthatmethanolisthebestsolventforthereaction.Thereactionrateequationwithv=k[Cat.][H2O2]1/2-[C3H5Cl]andtheapparentactivationenergywithEa=63.462kJ/molareobtainedaccordingtothekineticsstudy.
简介:<正>"AirHuarache2k5预计发售时间2005年3月26日,预计官方售价$130。"当这个消息发布之后,所有鞋迷都感到非常高兴,一款人们期盼已久的鞋终于要上市了。之前,由于AirHuarache2k5的前辈AirHuarache2k4时尚的外观,以及其包裹性、保护性、舒适性和鞋的轻量化近乎完美的融和,当之无愧地被鞋迷们评定为2004年最佳鞋款之一,因此人们对2K5的期望值达到了前所未有的高度。从2K5的样品图片面世的那一天起,这款鞋就被人们不断谈论,网上经常出现关于2K5的种种猜测,不过大都掺杂了自己的私人情感,没有什么实际根据。但是值得肯定的一点
简介:本文报道了C6H12O6(NH4)2SO4C2H5OHH2O(C2H5OH/H2O=0.90)体系在35℃时体系溶解度和饱和溶液的折光指数,并绘出了体系相应的溶度图和饱和溶液的折光指数曲线图。结果表明:所研究的体系为四元体系C6H12O6(NH4)2SO4C2H5OHH2O中的一部分。当溶液中肌醇饱和时,溶度曲线落在约50%的等醇水比面上。当(NH4)2SO4在溶液中达到饱和时,出现共饱点。其组成为(NH4)2SO4:210%,C6H12O6:2.08%,C2H5OH:4475%。同时出现分层,在富醇相随着乙醇浓度的增加,出现肌醇与硫酸铵共饱线。在富水相硫酸铵饱和溶度曲线落在约5%乙醇的等醇水比面上,折光指数曲线由三支组成,其中两条分别与C6H12O6·H2O和(NH4)2SO4相对应,另外一条线与(NH4)2SO4和C6H12O6·H2O的共饱线相对应