简介:PolycrystallinesamplesofLa12x(Sr12yAgy)xMnO3(y=0.0,0.2,0.4,0.6,1.0)werepreparedbythesolid-statereactionmethod.ThetemperaturestabilityofmagnetoresistanceandmagnetoresistanceenhancementinLa1-x(Sr1-yAgy)xMnO3systemwithbothunivalentandbivalentelementsdopedatAsiteandwithunchangedvalueofMn3+/Mn4+ratiowereexploredthroughthemeasurementsofX-raydiffractionpatterns,magnetiza-tion-temperature(M-T)curves,resistivity-temperature(q-T)curvesandmagnetoresistance-temperature(MR-T)curves.Theresultsareasfollows:therearetwopeaksintheq-TcurvesofthesampleswithAgdoping,oneiscausedbyresistancechangeduringtheparamagnetism-ferromagnetismtransition,andtheotherisfromboundary-dependentscatteringofconductionelectronsontheboundariesofgrains.ThepeakvalueofMRincreaseswithincreasingAgdopingcontent,anditincreasesfrom8.2%fory=0.2to29.6%fory=1.0underthemagneticfieldofB=0.8T;MRremainsaconstantof12%inthetemperaturerangeof218-168Kforthesamplewithy=1.0,andthetemperaturestabilityofMRisinfavorofthepracticalapplicationofMR.
简介:继续等待还是即刻实现LA40F71B集成了读卡器和VSB接口,用于浏览播放闪存设备上的照片和音乐,但和绝大多数具有此类功能的电视一样,
简介:Amachine,orothertypeof“system”,canoftenbedividedintoseveralsubsystems(components)andthesesubsystemsagaincanbedividedintosevreralsubsystems(secondgeneration).Thisprocessformsasystemtree.Toassessthereliabilityofthemachinebasedondatafromthetrialsofcomponentsofthemachine,virtualsystemmethodisemployed.ItisprovedinthepaperthatthelowerconfidentlimitofthereliabilityofthemachinesetbythevirtualsystemmethodislevelconsistentandasymptoticallyoptimalwhiletheonesetbyLindstrom-Maddensmethodisnot.
简介:Summary1.Thereare12powersystemsincluding5regionalpowersystemswithover1000MWofcapacityeach.In1989CentralandEastChinapowersystemswereinterconnectedbya±500kVHVDCLine.2.Thehierarchicalcontrolorganizationcanbedividedinto5levels,i.e.NCC,6RCCs,25PCCs,250DCCsandmorethan2000CCCs.3.AllcontrolcenterswillbeequippedwithSCADAandEMSinthenearfuture.4.Chinapowersystemhasalarge,dedicatedcommunicationnetworkofitsown.
简介:本篇文章要探讨的主题是"使用PC来达成高清影音的采集(录像)、压缩,个人广播的实用技术",若读者觉得太冗长的话,或者可以称之为"高清采集实战教学"。所谓的高清影音简单来说就是数字化1920×1080的影片加上2到6声道的数字音效。在台湾或是大陆地区,目前一般人常见收视到的卫星高清广播频道,包含有日本的BSDigital系统以及中央电视台的CCTV高清影视频道。高清影片的魅力就在于凡是收视过高清电视的用户们,一定都深深的被那清晰的影音效果吸引着,但是通常在收看高清电视没多久之后,一定会开始想要能够录像保存这些精彩的节目片段。也就在这个时候,才会开始注意到高清电视录像并不像是用VHS录像一样那么简单只要按下录像按钮就可以了。