The layered charges were calculated by means of constructing the complete structure of Tl Ba Ca Cu O superconductor. The weak link between Cu O and Ba O, or between Cu O and Tl O or Ba O or Tl O layers i...The layered charges were calculated by means of constructing the complete structure of Tl Ba Ca Cu O superconductor. The weak link between Cu O and Ba O, or between Cu O and Tl O or Ba O or Tl O layers is explained with the aid of the charge of limited layer unit calculated from the values of ions obtained, in addition to the possibility of forming charges fluctuation, which depends on the π coordination covalent bond on Cu O plane and O Tl O structure. The possible chemical tight bonding orbitals are in accordance with those of other superconductors obtained by quantum theoretical method, which occur at Cu 3d (x 2-y 2) and O 2p x,y . The valence band composed of Cu 3d and O 2p orbital energy levels is obviously an energy band of conduction. The ordered charge on layers is the main reason that raises T c of superconductors. The difference of electronic structure of ab plane and c axis leads to the anisotropy properties.展开更多
There are several paths for synthesizing 4,4′ bis(hydroxymethyl) 2,2′ bipyridine, but most of them need strict experimental conditions that are not easy to be overcome. We designed a simple way to prepare this produ...There are several paths for synthesizing 4,4′ bis(hydroxymethyl) 2,2′ bipyridine, but most of them need strict experimental conditions that are not easy to be overcome. We designed a simple way to prepare this product via the oxidation of 4,4′ bismethyl 2,2′ bipyridine, followed by esterification and reduction. The yield increases and the reaction conditions become genial in contrast to those of other methods. The molecular structure of the final product was confirmed by means of elemental analysis, IR, 1H NMR and MS spectra.展开更多
文摘The layered charges were calculated by means of constructing the complete structure of Tl Ba Ca Cu O superconductor. The weak link between Cu O and Ba O, or between Cu O and Tl O or Ba O or Tl O layers is explained with the aid of the charge of limited layer unit calculated from the values of ions obtained, in addition to the possibility of forming charges fluctuation, which depends on the π coordination covalent bond on Cu O plane and O Tl O structure. The possible chemical tight bonding orbitals are in accordance with those of other superconductors obtained by quantum theoretical method, which occur at Cu 3d (x 2-y 2) and O 2p x,y . The valence band composed of Cu 3d and O 2p orbital energy levels is obviously an energy band of conduction. The ordered charge on layers is the main reason that raises T c of superconductors. The difference of electronic structure of ab plane and c axis leads to the anisotropy properties.
基金Supported by the National Natural Science Foundation of China(No. 2 0 16 2 0 0 5 ) the Foundation of EducationMinistry(No. 2 0 0 1- 3) .
文摘There are several paths for synthesizing 4,4′ bis(hydroxymethyl) 2,2′ bipyridine, but most of them need strict experimental conditions that are not easy to be overcome. We designed a simple way to prepare this product via the oxidation of 4,4′ bismethyl 2,2′ bipyridine, followed by esterification and reduction. The yield increases and the reaction conditions become genial in contrast to those of other methods. The molecular structure of the final product was confirmed by means of elemental analysis, IR, 1H NMR and MS spectra.
