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:<正>Greetings…Allowmetobeginbyextending,onbehalfofthePhilippinedelegation,ourheartfeltgratitudetotheChineseAssociationforInternationalUnderstanding(CAFIU)forthisexcellentopportunityforgreaterunderstandingofChinaanditsrelationstothePhilippines,theASEANandtherestoftheworld.Thisexchangehaslikewisebeenanimportantoccasionforustoshareourinsightsontheserelationsinthelightofourcommoninterestsandaspirationsas
简介:<正>AttheinvitationoftheDanish-ChineseBusinessForum(DCBF),ZhouTienong,Vice-Chairmanofthe11thNationalPeople’sCongressStandingCommitteeandPresidentofCAFIU,ledaCAFIUdelegationtovisitDenmarkfromJune9thto12th.WhenwearrivedinCopenhagenat10:30pm,lookingattheskylineofthecopperdomesand
简介:StudiesontheZnO/La0.5Pr0.2Sr0.3MnO3(LPSMO)/SrNb0.002Ti0.998O3(SNTO)heterostructurehavingvaryingthicknessofp-typeLPSMO(100nm—LP1)and(200nm—LP2)manganitearecarriedout.ZnO/LPSMO(n—p)andLPSMO/SNTO(p—n)junctionsofboththeheterostructuresexhibitgoodrectifyingbehaviorinawiderangeoftemperatureandappliedfield.Forwardandreversebiascharacteristicsofboththejunctionsofheterostructuresshowoppositebehavior.Theobservationofnegativemagnetoresistance(MR)at5KandpositiveMRat300K,inboththeheterostructures,hasbeenexplainedinthecontextofinterfaceregioneffectsandfillingofenergybandsofLPSMOmanganite.Further,athightemperature,theheterostructuresexhibitlargetemperature(46%K-1)andfield(40%T-1)sensitivities.Dependenceoftransport,magnetotransport,I—Vandsensingpropertiesoftheheterostructures,onthetemperature,fieldandfilmthicknesseshavebeendiscussedinthiscommunication.
简介:目的探讨PET/MR融合显像在癫痫灶定位中的价值.方法选择行手术治疗的顽固性癫痫40例,术前均行癫痫发作间期头部18F-FDGPET和MR检查,行术前、术中脑电监测.结果40例发作间期头部18F-FDGPET检查35例阳性,阳性率为87.5%;MR检查30例阳性,阳性率为75.0%.PET检查与术前脑电监测癫痫灶完全一致率为60.0%,部分一致率为20.0%,MR检查与术前脑电监测癫痫灶完全一致率为40.0%,部分一致率15.0%.PET/MR检查与术前脑电监测癫痫灶完全一致率为80.0%,部分一致率20.0%;PET/MR检查与术中脑电监测癫痫灶位置完全一致率为82.5%,部分一致率为17.5%.40例手术均成功.术后随访2~3年,依据Engle疗效分级标准Ⅰ级33例,Ⅱ级2例,Ⅲ/Ⅳ级5例.结论PET/MR两种技术在癫痫灶定位中能优势互补,具有无创、高灵敏度的优点.
简介:摘要目的探究对膝关节内侧半月板后跟撕裂应用MR影像分析的价值。方法选择2012年12月至2013年12月在我院进行MR影像分析的膝关节内侧半月板后跟撕裂患者30例,结合影像学特征,分析伴随的征象。结果30例患者,28例患者MR表现是内侧的半月板后根形态、信号出现异常改变;轴位表现是内侧半月板根部出现放射状撕裂,冠状位的信号表现是出现截断,矢状位表现是空半月板征。伴发征象28例患者25例表现是内侧的半月板脱位;关节韧带损伤情况12例患者在矢状位方面可以发现前交叉的韧带形态出现改变,高信号异常;关节退变26例患者关节软骨出现高信号影,表现异常。结论对膝关节内侧半月板后跟撕裂,应用MR影像分析,软组织分辨力比较高,对于直接和间接征象的表现较为有效,值得临床推广。