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41.
A New Ceramide from the Basidiomycetes Armillaria mellea 总被引:2,自引:0,他引:2
Jin Ming GAO Ze Jun DONG Ji Kai LIU* Kunming Institute of Botany Chinese Academy of Sciences Kunming Northwest Sci. 《中国化学快报》2001,(2)
As one part of our study on the bioactive metabolites of the higher fungi in Yunnan Province, the chemical constituents of Armillaria mellea (Tricholomataceae) collected at Zhong Dian in Yunnan Province have been investigated. The present report deals with the structural elucidation of a new ceramide 1, named armillaramide, isolated from the AcOEt extract of the fruiting bodies of this fungus.Figure 1 The structure of armillaramide 1Compound 1, white amorphous powder, mp 113(117(C, [(] + … 相似文献
42.
<正>Two new oleanane-type saponins,crotalarioside A(1) and crotalarioside B(2),were isolated from the roots of Polygala crotalarioides.Their structures were elucidated on the basis of spectroscopic and chemical evidence. 相似文献
43.
Influence of arsenic,antimony and cobalt impurities on the cathodic process in zinc electrowinning 下载免费PDF全文
YU XiaoHua XIE Gang LI RongXing LI YongGang & LU Ying Faculty of Metallurgical Energy Engineering Kunming University of Science Technology Kunming China Technology Center of Yunnan Metallurgy Group Co. Kunming 《中国科学:化学》2010,(3)
By means of an electrochemical study,the influence of arsenic,antimony and cobalt on cathodic polarization in the zinc electrowinning process,the associated kinetic equations and parameters,and the polarization mechanism have been studied.The results show that the experimental values of the kinetic parameters are in accord with the theoretical values in the ZnSO4/H2SO4 solution with a single impurity is added.In contrast,the charge transfer coefficient α is smaller than the theoretical value in the ZnSO4/H2... 相似文献
44.
Xue Mei NIU Sheng Hong LI Li Yan PENG Gao Xiong RAO Han Dong SUN* Laboratory of Phytochmistry Kunming Institute of Botany Academia Sinica Kunming Yunnan College of Traditional Chinese Medicine Kunming 《中国化学快报》2001,(3)
Limonia crenulata Roxb. (Rutaceae), a small tree widely distributed in dry warm regions of southeastern Asia, has been reported to have antiepileptic, purgative and sudorific effects and is used for colic trouble and cardialgia1. Various parts of this plant have been employed in indigenous medicine. Our investigation on its stems led to the isolation of one new alkaloid, crenulatine 1, together with three known ones, 4-methoxy-6- hydroxy-1-methyl-2-quinolone2, N-benzoyltyramine methyl ether2,… 相似文献
45.
The ordered mesoporous aluminosilicate molecular sieve (MASMS-1) stable in the high-temperature steam has been successfully synthesized from the assembly of diluted ZSM-5-type precursor with mesoporous MCM-41. The material was characterized by XRD, N2 adsorption-desorption, FE-SEM, TEM, FT-IR spectroscopy and 27A1 MAS NMR techniques. This mesoporous material shows high stability in the high-temperature steam [H2O (φ=20%) in N2 at 800 ℃ for 4 h], which might be ascribed to the synergistic effect of both thick walls containing zeolite-like five-membered ring subunits and highly condensed surface silanol groups. 相似文献
46.
离子膜富集—XRFA法测定Cr(Ⅲ)和Cr(Ⅵ) 总被引:1,自引:0,他引:1
本文利用离子交换膜富集和分离Cr(Ⅲ)与Cr(Ⅵ),并用XRFA测定。 相似文献
47.
Tao Hong Li Chuan Ming Wang Shi Wen Yu Xiang Yi Liu Hui Fu Xiao Guang Xie 《中国化学快报》2009,20(8):1010-1014
The reaction of Os~+(~6D,~4F) with N_2O has been investigated at B3LYP/TZVP and CCSD(T)/6-311+G~* levels of theory.The mechanisms corresponding to O-atom and N-atom transfer reactions have been revealed.It was found that on the sextet reaction surface both the O-atom and N-atom transfer reactions undergo through direct-abstraction mechanism,leading to the formation of OsO~+ and OsN~+,whereas on quartet surface the two reactions undergo through O-N bond or N-N bond insertion mechanism.The calculated energ... 相似文献
48.
49.
Images of the velocity cross--section at 10 different depths in Yunnan Province have been suc-cessfully reconstructed, using the principle and method of seismic tomography (ST). These velocitycoss-sections are consistent with the results of six velocity profiles of deep seismic sounding. The reconstruction method of ST used in this paper has two advantages: (i) The velocity modeli determined by spe cifying node--velocities of hexahedron and linear interpolation through knownbasic function. A velocity field with lateral continuous velocity value and vertical discontinuitiesis established. This model is obviously better than the block model of constant velocity. The verticaldiscontinuities allow the model to simulate velocity discontinuities in the crust and upper mantle. (ii)The velocity and hypocenter parameters are separated by introducing an orthogonal projection oper-ator. Sequential orthogonal triangularization and modified singular decomposition are adopted.These measures reduce the RAM requirement 相似文献
50.
NixZry(x:y=1∶2或2∶1)团簇的量子化学研究 总被引:3,自引:0,他引:3
根据化学键理论和拓扑学原理,设计了非晶态团簇NixZry(x:y=1:2或2:1,x+y≤9)的几十种可能的构型,并应用量子化学从头算方法对它们的几何构型进行了优化,分析比较了这些构型的能量和稳定性。结果表明对于NixZry(x:y=1:2)低对称性的平面构型最稳定,而NixZry(x:y=2:1)三棱柱构型最稳定。这可能是由于两者外层价电子的数量差异所致:Zr仅有4价电子,较适宜配位数低的平面构型,而Ni(4s^23d^8),更适宜立体构型。 相似文献