The solidification structure of Bi-3 wt pct Mn alloy grown up in the semisolid zone under the influence of a staticmagnetic field (up to 1.0 T) and the relation of the magnetic property with the solidification structu...The solidification structure of Bi-3 wt pct Mn alloy grown up in the semisolid zone under the influence of a staticmagnetic field (up to 1.0 T) and the relation of the magnetic property with the solidification structure have beeninvestigated experimentally. It was shown that the primary phase MnBi crystals in the alloy aligned and oriented alongthe direction of the applied magnetic field. The orientating tendency and the average length of the elongated MnBicrystals increased with the increase of the applied field and the solidification time. Moreover, the remanence of thealloy along the aligned direction of the MnBi phase in the case of solidification with a magnetic field was apparentlyanisotropic and nearly double of that without the magnetic field. This indicated that the MnBi crystals orientedand aligned along their easy magnetization axis. A model was proposed to explain the alignment and orientationgrowth of the MnBi crystals in a magnetic field in terms of the magnetic anisotropy of the crystals and the magneticinteraction between them.展开更多
Three new homochiral bis-diamine-bridged bi-Mn（salen） complexes were synthesized. Their catalysis on asymmetric epoxidation of a-methylstyrene, styrene and indene was studied with NaC10 and m-CPBA as oxidants respec...Three new homochiral bis-diamine-bridged bi-Mn（salen） complexes were synthesized. Their catalysis on asymmetric epoxidation of a-methylstyrene, styrene and indene was studied with NaC10 and m-CPBA as oxidants respectively. This homogeneous catalyst exhibited comparable catalytic activity and enantioselectivity to the Jacobsen＇s catalyst in the asymmetric epoxidation of unfunctionalized olefins. Furthermore, the catalyst could be conveniently recovered and reused at least five times without significant losses of both activity and enantioselectivity. Specially, it also could be efficiently used in large-scale reactions with superior catalytic disposition being maintained at the same level, which provided the potential for the applications in industry. The effect of axial bases, temperature and solvent on activity and enantioselectivity of the catalytic system were also studied.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.59871026,50225416,50234020)“Shu Guang”Shanghai Education Development Foundation(No.98SG37).
文摘The solidification structure of Bi-3 wt pct Mn alloy grown up in the semisolid zone under the influence of a staticmagnetic field (up to 1.0 T) and the relation of the magnetic property with the solidification structure have beeninvestigated experimentally. It was shown that the primary phase MnBi crystals in the alloy aligned and oriented alongthe direction of the applied magnetic field. The orientating tendency and the average length of the elongated MnBicrystals increased with the increase of the applied field and the solidification time. Moreover, the remanence of thealloy along the aligned direction of the MnBi phase in the case of solidification with a magnetic field was apparentlyanisotropic and nearly double of that without the magnetic field. This indicated that the MnBi crystals orientedand aligned along their easy magnetization axis. A model was proposed to explain the alignment and orientationgrowth of the MnBi crystals in a magnetic field in terms of the magnetic anisotropy of the crystals and the magneticinteraction between them.
基金financially supported by National Ministry of Science and Technology Innovation Fund for High-tech Small and Medium Enterprise Technology (09C26215112399)National Ministry of Human Resources and Social Security Start-up Support Projects for Students Returned to Business, Office of Human Resources and Social Security Issued 2009 (143)
文摘Three new homochiral bis-diamine-bridged bi-Mn（salen） complexes were synthesized. Their catalysis on asymmetric epoxidation of a-methylstyrene, styrene and indene was studied with NaC10 and m-CPBA as oxidants respectively. This homogeneous catalyst exhibited comparable catalytic activity and enantioselectivity to the Jacobsen＇s catalyst in the asymmetric epoxidation of unfunctionalized olefins. Furthermore, the catalyst could be conveniently recovered and reused at least five times without significant losses of both activity and enantioselectivity. Specially, it also could be efficiently used in large-scale reactions with superior catalytic disposition being maintained at the same level, which provided the potential for the applications in industry. The effect of axial bases, temperature and solvent on activity and enantioselectivity of the catalytic system were also studied.
