简介：当你在拍摄移动着的物体的时候,比如说拍行走着的路人,要想拍摄到没有抖动且清晰的图像,相机的快门速度最好设置在1/250秒左右。对于更快的动作,就应设置成更高的速度。几乎所有的数码相机,最高的快门速度都在1/500秒-1/2000秒,因此从理论上来说,基本上所

简介：2009年岁末福州的最后一次拍地格外引人注目，12月25日上午九点，福州市国土资源局拍卖大厅已经是人山人海，伴随主持人手中锤子敲动的是愈叫愈高的竞拍价，“1亿3千万”、“1亿3千3百万”……竞拍人的声音此起彼伏，紧紧跟随。此次拍卖会，经正式确认、并有资格参与9块地拍卖的竞拍人共57家，这是2008年以来参与土地竞拍人数最多的一次!

简介：基于重叠网格技术对拍动翼运动进行数值模拟研究.系统地分析拍动翼的运动参数（包括升沉俯仰相位差、俯仰幅值及斯特劳哈尔数等）对推进性能的影响.结合推进效率及拍动翼后方的涡流场结构确立最佳运动参数.该求解方法可为其他动边界问题的处理提供参考.

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简介：AIM:Tocomparetheregularityandaccuracyoflaserinsitukeratomileusis(LASIK)flapscreatedbytheZiemerFEMTOLDV'Classic'(Ziemer'Classic')andZiemerFEMTOLDVCrystalLinefemtosecondlaser(ZiemerCrystalLine).METHODS:Fourier-domainopticalcoherencetomography(RTVueOCT)wasusedtomeasurethemorphologyof200LASIKflapsof100consecutivepatientscreatedwiththeZiemerClassic(100flaps)ortheZiemerCrystalLine(100flaps)atoneweekpostoperatively.Flapthicknesswasevaluatedat36specifiedmeasurementpointsoneachflap.Forallprocedureswithbothlasers,thenominalflapthicknesswas110μm.RESULTS:ThemeanflapthicknessoftheZiemerCrystalLinegroup(102.49±2.68μm)wasthinnerthanthatoftheZiemerClassicgroup(107.65±5.09μm)(P<0.01).Averagethicknessofallflapswasuniformwithin4μmatallmeasurementpoints.TheflapsintheZiemerCrystalLinegroupweremoreregularthanthoseintheZiemerClassicgroupwhenmeasuredfromthecentertotheperiphery.Themaximumdeviationfromthenominal110μmof36measurementswas8μmintheZiemerClassicgroup,whileintheZiemerCrystalLinegroupitwas9μm.Withinthe3600measurementsonthe100eyes,differencesgreaterthan20μmwereobserved0.14%intheZiemerClassicgroup,and0.04%intheZiemerCrystalLinegroup.CONCLUSION:TheflapscreatedwiththeZiemerFEMTOLDVCrystalLinefemtosecondlaseraremoreuniformandthinnerthanthosecreatedbytheZiemerFEMTOLDVClassicfemtosecondlaser.

简介：AIM:Tostudytheimpactofscleralflapposition,underwhichtheposteriorchamberintraocularlenses(PC-IOL)weresulcus-fixedbytrans-scleralsuture,oncorneaastigmatism.METHODS:Twenty-sixaphakicorcataracteyeswerecomprisedinthisprospectivenoncomparativecaseseriesstudy.Eleveneyeshadtraumaticcataractremovedwithoutsufficientcapsularsupport,3hadblunttraumawithsubluxatedtraumaticcataract,8hadundergonevitreoretinalsurgeryand4hadcongenitalcataractremoved.Theaverageagewas54years(range21-74years),with17menand7women.ThefoldablePC-IOLwasfixedinsulcusbytrans-scleralsuture.TheincisionforIOLimplantationwasmade1mmposteriortolimbusalongthesteepestmeridianofcornea,whilescleralflapstoburytheknotsoftrans-scleralsutureweremadealongtheflattestmeridian.Allthesurgerieswereperformedbyasingledoctor(MaL),andthefollowupwasatleast13months(range13-28months).Thepreoperative,3monthsand1yearpostoperativecornealcurvaturealongthesteepestandflattestcorneameridianandoverallcorneaastigmatismwerecompared.RESULTS:Thecurvaturealongthesteepestmeridianchangedfrom44.25±2.22Dpreoperativelyto44.08±2.16Dat3monthspostoperatively,and43.65±5.23Dat1yearpostoperatively(P>0.05);thecurvaturealongtheflattestmeridianchangedfrom41.24±2.21Dpreoperativelyto43.15±3.94Dat3monthspostoperatively,and42.85±5.17Dat1yearpostoperatively(P<0.05);andthesurgeryinducedastigmatism(SIA)oncorneawascalculatedbyvectoranalysis,whichwas2.42±2.13Dat3monthspostoperatively,and2.18±3.42Dat1yearpostoperatively,thedifferencewasstatisticallysignificant(P<0.05).CONCLUSION:Thescleralflapmadealongtheflattestmeridian,underwhichtheposteriorchamberintraocularlenses(PCIOL)weresulcus-fixedbytrans-scleralsuture,cansteepenthecorneainvaryingdegrees,thusreducingpreexistingcornealastigmatism.