简介:随着2005年10月发布的E-500数码单反相机,奥林巴斯的4/3阵营又增加了一支生力军,成为继2003年发布的E-1、2004年发布的E-300后的第三位成员,也再次掀开了“O记”的新战役。从E-1的发布到今天,E系统已经整整走过了3个年头了,凭借其优异、独特的成像特点、品质卓越的镜头以及独一无二的超声波除尘系统,E系列单反相机受到越来越多用户的青睐,也再次证明了奥林巴斯正确的抉择。这里我们将E系列目前的三款相机做一个详尽的分析,进行一下这三款产品的横向测评。
简介:Numericalestimatesforelectronsandmesonsparticle–antiparticlecreationfromvacuuminthepresenceofstrongelectromagneticfieldsarederived,usingthecompleteprobabilitydensityrelationofPopov’simaginarytimemethod(Popov,JETPLett.13,185(1971);Sov.Phys.JETP34,709(1972);Sov.Phys.JETP35,659(1972);PopovandMarinov,Sov.J.Nucl.Phys.16,449(1973);JETPLett.18,255(1974);Sov.J.Nucl.Phys.19,584(1974));(Popov,Phys.Let.A298,83(2002)),andwithintheframeworkofanexperimentalsetupliketheE144(Burkeetal.,Phys.Rev.Lett.79,1626(1997)).Theexistenceofcrossingpointamongpaircreationefficiencycurvesofdifferentphotonenergiesandtheroleofodd/evenmultiphotonordersintheproductionratesarediscussed.Finallyakindoftunabilityprocessbetweenthetwocreationprocessesisdiscussed.
简介:Usingfourβ-cyclodextrinderivatives,2,6-di-O-benzyl-3-O-heptanonyl-β-CD,2,6-di-O-benzyl-3-O-octanonyl-β-CD,2,3-di-O-benzyl-6-O-heptanonyl-β-CD,and2,3-di-O-benzyl-6-O-octanonyl-β-CD,aschiralstationaryphasesofcapillarygaschromatography(CGC),theenantiomersofSharplessepoxideswerewellseparated.Theenantiomerexcessvalues(e.e.%)ofsomechiralSharplessepoxideswerealsodeterminedsuccessfullyusingtheseCDs.