在减压降温液氮温区(约64K),采用磁缀饰法(即高分辨Bitter图法),分别在熔融织构生长(MTG)的YBa_2Cu_3O_7超导体和射频溅射制备的单晶外延YBa_2Cu_3O_7薄膜上用KYKY-1000 B SEM观察到超导体的磁通分布图,属无序非晶态结构。在MTG超导体...在减压降温液氮温区(约64K),采用磁缀饰法(即高分辨Bitter图法),分别在熔融织构生长(MTG)的YBa_2Cu_3O_7超导体和射频溅射制备的单晶外延YBa_2Cu_3O_7薄膜上用KYKY-1000 B SEM观察到超导体的磁通分布图,属无序非晶态结构。在MTG超导体中得到清晰的孪晶界、层界和晶体缺陷对磁通的钉扎图象。最强的钉扎中心出现在尺寸较大的Y_2BaCuO_5(211)第二相粒子周围。展开更多
A major phase in high Tc Y-Ba-Cu oxide with zero resistance at 91K and high volume fraction of diamagnetic superconductive phase has been identified by electron diffraction.It appears to be an orthorhombic twinned str...A major phase in high Tc Y-Ba-Cu oxide with zero resistance at 91K and high volume fraction of diamagnetic superconductive phase has been identified by electron diffraction.It appears to be an orthorhombic twinned structure with a=3.89Å,b=3.82Å and c=11.7lÅ.Some defects were observed by TEM.展开更多
With the discovery and further understanding of topoisomerases, it becomes clear that the supercoiling of double stranded DNA plays an important role in DNA replication, RNA transcription and even in the control of ge...With the discovery and further understanding of topoisomerases, it becomes clear that the supercoiling of double stranded DNA plays an important role in DNA replication, RNA transcription and even in the control of gene expression. Although the small circular DNA can be separated by means of density gradient centrifugation or gel electrophoresis and展开更多
文摘在减压降温液氮温区(约64K),采用磁缀饰法(即高分辨Bitter图法),分别在熔融织构生长(MTG)的YBa_2Cu_3O_7超导体和射频溅射制备的单晶外延YBa_2Cu_3O_7薄膜上用KYKY-1000 B SEM观察到超导体的磁通分布图,属无序非晶态结构。在MTG超导体中得到清晰的孪晶界、层界和晶体缺陷对磁通的钉扎图象。最强的钉扎中心出现在尺寸较大的Y_2BaCuO_5(211)第二相粒子周围。
文摘A major phase in high Tc Y-Ba-Cu oxide with zero resistance at 91K and high volume fraction of diamagnetic superconductive phase has been identified by electron diffraction.It appears to be an orthorhombic twinned structure with a=3.89Å,b=3.82Å and c=11.7lÅ.Some defects were observed by TEM.
文摘With the discovery and further understanding of topoisomerases, it becomes clear that the supercoiling of double stranded DNA plays an important role in DNA replication, RNA transcription and even in the control of gene expression. Although the small circular DNA can be separated by means of density gradient centrifugation or gel electrophoresis and
