学科分类
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2 个结果
  • 简介:ChinaandtheU.S.havemadesomeprogressindealingwithillicitdrugthreat.Theircooperation,however,hasnotalwaysbeensmooth.Thetwosidesneedtoimprovemutualtrusts,increaseanti-druglawenforcementcooperationandpushforaninternationalinformationsharingsystemtostopdrugstrafficking.

  • 标签: 合作 进程 管制 生产地区 三角和 阿富汗
  • 简介:Wetheoreticallypresenttheintrinsiclimitstoelectronmobilityinthemodulation-dopedAlGaN/GaNtwo-dimensionalelectrongas(2DEG)duetoeffectsincludingacousticdeformationpotential(DP)scattering,piezoelectricscattering(PE),andpolar-opticphononscattering(POP).WefindthatDEandPEarethemoresignificantlimitingfactorsatintermediatetemperaturesof40Kto250K,whilePOPbecomesdominantasroomtemperatureisapproached.Detailednumericalresultsarepresentedforthechangeofelectronmobilitywithrespecttotemperatureandcarrierdensity.Weconcludethatthesethreetypesofphononscattering,whicharegenerallydeterminedbythematerialpropertiesbutnotthetechnicalprocessing,arehardlimitstothe2DEGmobility.

  • 标签: 光学声子散射 AlGaN 电子迁移率 二维电子气 调制掺杂 2DEG