目的研究桑Morus alba L.枝的化学成分。方法桑枝60%乙醇提取液采用ODS、Sephadex LH-20、半制备柱进行分离纯化,根据理化性质及波谱数据鉴定所得化合物的结构。结果从中分离得到10个化合物,分别鉴定为4'-O-β-D-吡喃葡萄糖基-2...目的研究桑Morus alba L.枝的化学成分。方法桑枝60%乙醇提取液采用ODS、Sephadex LH-20、半制备柱进行分离纯化,根据理化性质及波谱数据鉴定所得化合物的结构。结果从中分离得到10个化合物,分别鉴定为4'-O-β-D-吡喃葡萄糖基-2'-羟基大花藜芦酚3-(6-O-β-D-吡喃葡萄糖基-β-D-吡喃葡萄糖苷)(1)、3-O-β-D-吡喃葡萄糖基-2'-羟基大花藜芦酚4'-(6-O-β-D-吡喃葡萄糖基-β-D-吡喃葡萄糖苷)(2)、桑皮苷A(3)、桑皮苷E(4)、桑皮苷F(5)、反式氧化白藜芦醇-4-O-β-D-吡喃葡萄糖苷(6)、反式氧化白藜芦醇-3-O-β-D-吡喃葡萄糖苷(7)、顺式桑皮苷A(8)、3,4-二甲氧基苯基β-D-呋喃芹糖基-(1→6)-β-D-吡喃葡萄糖苷(9)、kelampayoside A(10)。结论化合物9、10为首次从桑属植物中分离得到,化合物1、2、4~7为首次从该植物中分离得到。展开更多
A new method of 3 D transient eddy current field calculation is proposed. The Maxwell equations with time component elimination(METCE) are derived under the assumption of magnetic quasi static approximation, especiall...A new method of 3 D transient eddy current field calculation is proposed. The Maxwell equations with time component elimination(METCE) are derived under the assumption of magnetic quasi static approximation, especially for the sample of low conductivity. Based on METCE, we deduce a more efficient reconstruction algorithm of a3 D transient eddy current field. The computational burden is greatly reduced through the new algorithm, and the computational efficiency is improved. This new algorithm decompounds the space-time variables into two individual variables. The idea is to solve the spatial vector component firstly, and then multiply it by the corresponded time component. The iterative methods based on METCE are introduced to recover the distribution of conductivity in magneto-acoustic tomography. The reconstructed images of conductivity are consistent with the original distribution, which validate the new method.展开更多
文摘目的研究桑Morus alba L.枝的化学成分。方法桑枝60%乙醇提取液采用ODS、Sephadex LH-20、半制备柱进行分离纯化,根据理化性质及波谱数据鉴定所得化合物的结构。结果从中分离得到10个化合物,分别鉴定为4'-O-β-D-吡喃葡萄糖基-2'-羟基大花藜芦酚3-(6-O-β-D-吡喃葡萄糖基-β-D-吡喃葡萄糖苷)(1)、3-O-β-D-吡喃葡萄糖基-2'-羟基大花藜芦酚4'-(6-O-β-D-吡喃葡萄糖基-β-D-吡喃葡萄糖苷)(2)、桑皮苷A(3)、桑皮苷E(4)、桑皮苷F(5)、反式氧化白藜芦醇-4-O-β-D-吡喃葡萄糖苷(6)、反式氧化白藜芦醇-3-O-β-D-吡喃葡萄糖苷(7)、顺式桑皮苷A(8)、3,4-二甲氧基苯基β-D-呋喃芹糖基-(1→6)-β-D-吡喃葡萄糖苷(9)、kelampayoside A(10)。结论化合物9、10为首次从桑属植物中分离得到,化合物1、2、4~7为首次从该植物中分离得到。
基金Supported by the National Natural Science Foundation of China under Grant Nos 51137004,61427806 and 51577184the Equipment Development Project of Chinese Academy of Sciences under Grant No YZ201507
文摘A new method of 3 D transient eddy current field calculation is proposed. The Maxwell equations with time component elimination(METCE) are derived under the assumption of magnetic quasi static approximation, especially for the sample of low conductivity. Based on METCE, we deduce a more efficient reconstruction algorithm of a3 D transient eddy current field. The computational burden is greatly reduced through the new algorithm, and the computational efficiency is improved. This new algorithm decompounds the space-time variables into two individual variables. The idea is to solve the spatial vector component firstly, and then multiply it by the corresponded time component. The iterative methods based on METCE are introduced to recover the distribution of conductivity in magneto-acoustic tomography. The reconstructed images of conductivity are consistent with the original distribution, which validate the new method.
