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:柳州市作为全国18个“优化资本结构”试点城市之一,得到我区各部门的大力支持,自治区经委正积极协助,配合柳州市做好工作。按照自治区经委部署,全系统将着力抓好以下工作:第一,围绕“增资、改造、分流、破产”的主要试点内容,用足用好已出台的有关改革政策措施,抓紧制订并落实有关的配套实施意见、办法。选择一些国有企业在财政、银行、企业之间进行债务重组的探索试点。要有计划有组织地选择一些资不抵债、扭亏无望的国有企业,实施破产试点,注意总结经验教训,以利推广。尽快出台及组织实施国有企业分流富余人员的政策、措施。第二,抓好柳州市11户纳入自治区建立现代企业制度试点企业的工作;要利用试点城市的优势和有利条件,率先
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.