A rare earth Schiff base complex:lanthanum tris(N-phenylethyl-3,5-di-t-butylsalicylaldiminato)s [La(OPEBS)_3] was successfully applied as single component initiator for the ring-opening polymerization of 1,4-dioxan-2-...A rare earth Schiff base complex:lanthanum tris(N-phenylethyl-3,5-di-t-butylsalicylaldiminato)s [La(OPEBS)_3] was successfully applied as single component initiator for the ring-opening polymerization of 1,4-dioxan-2-one (PDO) in bulk.The influence of reaction conditions,such as polymerization temperature,the molar ratio of the monomer to initiator (M/I) on the monomer conversion and molecular weight of the polymer has been investigated.Poly(1,4-dioxan-2-one) with a viscosity-average molecular weight (My) o...展开更多
In order to continue our studies on the synthesis, properties and coordination of s-tetrazine, 3,6-di-（pyridin-3-yl）-s-tetrazine （Ⅱ, 3-dptz） was synthesized and characterized by ^1HNMR, MS and IR spectra. And the...In order to continue our studies on the synthesis, properties and coordination of s-tetrazine, 3,6-di-（pyridin-3-yl）-s-tetrazine （Ⅱ, 3-dptz） was synthesized and characterized by ^1HNMR, MS and IR spectra. And the coordination reaction of 3-dptz with nitrate of Cu（Ⅱ） was studied. 3-dptz reacting with CuⅡ salt [Cu（NO3）2·2H2O] generates a new salt, nitrate of 2,5-di-（pyridin-3- yl）-1,3,4-oxadiazolene （Ⅲ）. Ⅲ was determined by IR spectra and single-crystal X-ray diffraction to give the following crystal data： space group P21/c, a = 4.9112（1）, b = 8.4101（3）, c = 29.499（1）（A）, β = 93.266（2）°, V = 1216.44（7） nm^3, Mr = 287.24, Z = 4, Dc = 1.568 g/cm^3,μ= 0.122 mm^-1, F（000） = 592, R = 0.0430 and wR = 0.1240. The results show that Ⅲ is composed of one cation and one nitrate anion. The cation consists of one H＋ and one 2,5-di-（pyridin-3-yl）-1,3,4-oxadiazol molecule, with the former being attached to the latter via electrovalent bond with N3 atom. And the O（42） atom in the nitrate anion is disordered. Intra- and intermolecular H-bonds are observed in the crystal of the title compound. The mechanism of metal-assisted decomposition was also discussed briefly.展开更多
为了充分利用非圆信号共轭相关不为零的特性,提高空间到达角(direction of arrival,DOA)和极化参数估计精度,提出了一种信号DOA和极化参数估计的稳健算法.即构造2个非圆信号的4阶累积量矩阵,引入旋转不变子空间(estimation of signal pa...为了充分利用非圆信号共轭相关不为零的特性,提高空间到达角(direction of arrival,DOA)和极化参数估计精度,提出了一种信号DOA和极化参数估计的稳健算法.即构造2个非圆信号的4阶累积量矩阵,引入旋转不变子空间(estimation of signal parameters via rotational invariance techniques,ESPRIT)算法思想,利用这2个矩阵之间的旋转不变特性求出旋转因子,实现信号DOA和极化参数更精确估计.与2阶相域ESPRIT相比,改进的算法适用于任意极化状态的信号,提高估计信号的利用率,同时利用4阶累积量对高斯噪声的抑制性处理相关噪声,使估计信号的精度有了明显提升,并通过仿真结果验证了改进算法的有效性.展开更多
A new compound, 3,6,20（S）-trihydroxy- 12,23-epoxydammar-24-ene,6,20-di-O-β-D-glucopyranoside （1）, was isolated from the leaves of Panax ginseng C.A. Meyer, whose structural elucidation was carried out by means of...A new compound, 3,6,20（S）-trihydroxy- 12,23-epoxydammar-24-ene,6,20-di-O-β-D-glucopyranoside （1）, was isolated from the leaves of Panax ginseng C.A. Meyer, whose structural elucidation was carried out by means of spectral analysis （including IR, HR- FAB-MS and NMR）. This compound showed the moderate cytotoxic activities against U937 and HeLa cells by using the MTT method.展开更多
A new halogenated biindole and a new apo-carotenone have been isolated from the ethanolic extract of the green alga Chaetomorpha basiretorsa Sethcell. On the basis of chemical and spectroscopic methods including 2D NM...A new halogenated biindole and a new apo-carotenone have been isolated from the ethanolic extract of the green alga Chaetomorpha basiretorsa Sethcell. On the basis of chemical and spectroscopic methods including 2D NMR technique, their structures have been elucidated as 4,4′-dichloro-5,5′-dibromo-7,7′-dimethoxy-2,2′-bi-1H-indole and 1′S*,4′R*-8-(4′-hydroxy-2′,6′,6′- trimethylcyclohex-2-enyl)-6-methyloct-3E,5E,7E-trien-2-one, respectively.展开更多
基金supported by the National Natural Science Foundation of China (Key program,Nos.G20434020 and G20774078).
文摘A rare earth Schiff base complex:lanthanum tris(N-phenylethyl-3,5-di-t-butylsalicylaldiminato)s [La(OPEBS)_3] was successfully applied as single component initiator for the ring-opening polymerization of 1,4-dioxan-2-one (PDO) in bulk.The influence of reaction conditions,such as polymerization temperature,the molar ratio of the monomer to initiator (M/I) on the monomer conversion and molecular weight of the polymer has been investigated.Poly(1,4-dioxan-2-one) with a viscosity-average molecular weight (My) o...
基金This work was financially supported by Young Science Fund of Zhejiang Sci-Tech University
文摘In order to continue our studies on the synthesis, properties and coordination of s-tetrazine, 3,6-di-（pyridin-3-yl）-s-tetrazine （Ⅱ, 3-dptz） was synthesized and characterized by ^1HNMR, MS and IR spectra. And the coordination reaction of 3-dptz with nitrate of Cu（Ⅱ） was studied. 3-dptz reacting with CuⅡ salt [Cu（NO3）2·2H2O] generates a new salt, nitrate of 2,5-di-（pyridin-3- yl）-1,3,4-oxadiazolene （Ⅲ）. Ⅲ was determined by IR spectra and single-crystal X-ray diffraction to give the following crystal data： space group P21/c, a = 4.9112（1）, b = 8.4101（3）, c = 29.499（1）（A）, β = 93.266（2）°, V = 1216.44（7） nm^3, Mr = 287.24, Z = 4, Dc = 1.568 g/cm^3,μ= 0.122 mm^-1, F（000） = 592, R = 0.0430 and wR = 0.1240. The results show that Ⅲ is composed of one cation and one nitrate anion. The cation consists of one H＋ and one 2,5-di-（pyridin-3-yl）-1,3,4-oxadiazol molecule, with the former being attached to the latter via electrovalent bond with N3 atom. And the O（42） atom in the nitrate anion is disordered. Intra- and intermolecular H-bonds are observed in the crystal of the title compound. The mechanism of metal-assisted decomposition was also discussed briefly.
文摘为了充分利用非圆信号共轭相关不为零的特性,提高空间到达角(direction of arrival,DOA)和极化参数估计精度,提出了一种信号DOA和极化参数估计的稳健算法.即构造2个非圆信号的4阶累积量矩阵,引入旋转不变子空间(estimation of signal parameters via rotational invariance techniques,ESPRIT)算法思想,利用这2个矩阵之间的旋转不变特性求出旋转因子,实现信号DOA和极化参数更精确估计.与2阶相域ESPRIT相比,改进的算法适用于任意极化状态的信号,提高估计信号的利用率,同时利用4阶累积量对高斯噪声的抑制性处理相关噪声,使估计信号的精度有了明显提升,并通过仿真结果验证了改进算法的有效性.
文摘A new compound, 3,6,20（S）-trihydroxy- 12,23-epoxydammar-24-ene,6,20-di-O-β-D-glucopyranoside （1）, was isolated from the leaves of Panax ginseng C.A. Meyer, whose structural elucidation was carried out by means of spectral analysis （including IR, HR- FAB-MS and NMR）. This compound showed the moderate cytotoxic activities against U937 and HeLa cells by using the MTT method.
基金supported by national 863 project(Grant No.2004AA625030,2001AA620503)NNSFC(Grant No.20432030)Key Innovative Project of the Academy(Grant No.KZCX3-SW-215).
文摘A new halogenated biindole and a new apo-carotenone have been isolated from the ethanolic extract of the green alga Chaetomorpha basiretorsa Sethcell. On the basis of chemical and spectroscopic methods including 2D NMR technique, their structures have been elucidated as 4,4′-dichloro-5,5′-dibromo-7,7′-dimethoxy-2,2′-bi-1H-indole and 1′S*,4′R*-8-(4′-hydroxy-2′,6′,6′- trimethylcyclohex-2-enyl)-6-methyloct-3E,5E,7E-trien-2-one, respectively.
