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951.
HgBa2Can-1CunO2n+2+( (n=1, 2, 3, 4) 1 are tetragonal with space group space P4/mmm. For n=1,2,3, nearly single-phase crystals were obtained, while for n=4, the sample was primarily a mixture of the n=3 and 4 phases. These materials also possessed the highest Tc values yet observed for any superconductors. In this paper, the valences of elements in the title compounds were calculated from bond valence sum method 2. The calculated bond covalency, valences of elements were summarized in Table …  相似文献   
952.
利用已合成的聚醋酸乙烯酯-甲基丙烯酸缩水甘油酯-甲基丙烯酸烯丙酯大孔共聚物。醇解后与6-氨基正已酸反应,进一步在EDAC的作用下实现与间氨基苯硼酸的偶联,得到亲水性的亲和吸附剂;配基密度为0.865mmol/g干树脂,偶联效率为89%,以云芝糖肽八方地,吸附容量为53.7mg/g干树脂,为醇解前的7.7倍。  相似文献   
953.
This presented study is to make comparison of cross sections to produce 117Sb and 90Nb via different reactions with particle incident energy up to 70 MeV as a part of systematic studies on particle-induced activations on enriched Sn, Y2O3 and ZrO2 targets, theoretical calculation of production yield, calculation of required thickness of target and suggestion of optimum reaction to produce Antimony-117 and Niobium-90.  相似文献   
954.
Three tripod molecules, tris(2-methoxy-5-nitrobenzyl)phosphine oxide (1), tris(2-butoxy-3-methyl-5-nitrobenzyl)phosphine oxide (2), and tris(3-nitrobenzyl)amine (TNBA), were synthesized and crystallized. The structures of 1, 2, and their comparison (TNBA) were determined by X-ray crystallography. It is noteworthy that compound 1 interacted with adjacent molecules via π-π stacking and C-H···π interactions to yield an open supramolecular network with the porosity P in 8.9%, whereas compound 2 gathered closely...  相似文献   
955.
Consider a generalized 3-body problem. The attraction force between any two bodies is proportional to the two masses and the b-th power of the mutual distance. Albouy and Fu have obtained the optimal upper bound of the number of generalized Euler configurations for the cases b 1 and b = 2, 3. This paper obtains the optimal upper bound for the remaining real values of b in a systematic way.  相似文献   
956.
Bulk metallic glasses (BMGs) with large supercooled liquid region are promising materials for superplastic forming. In this paper, we demonstrate a microstructure-based strategy to pinpoint the composition with the largest supercooled liquid region in La 86 x Al 14 Cu x (x=16 at%-20 at%) metallic glass system. By monitoring the changes in crystallization behavior of the glassy alloys with composition to search for the alloys exhibiting eutectic crystallization, the glassy alloys with the largest supercooled...  相似文献   
957.
An unusual oleanane triterpene(1) was isolated from aerial parts of Rhododendron campanulatum.The compound had shown prominent antibacterial and immunomodulatory activities.The structure of the compound was determined by spectroscopic data including 1D and 2D NMR spectral analysis.  相似文献   
958.
The odd-parity high-lying states of the Sm atom are investigated systematically by a three-color resonant excitation scheme with two different excitation paths.The two intermediate states,4f 6 6s7s 7 F 0 and 4f 6 6s7s 7 F 1 are employed for paths I and II,respectively.Fifty-seven bound states are detected with paths I and II in the energy range between 44188 and 45515 cm 1,while 64 autoionizing states are found in the energy range from 45528 to 45761 cm 1.Not only the level energies of all observed states,b...  相似文献   
959.
Two New Diterpene Alkaloids from the Roots of Spiraea japonica var. Acuta   总被引:1,自引:0,他引:1  
Spiraea japonica L. (Rosaceae) is widely distributed in Yunnan Provence, P. R. China. Previous chemical investigations on S. japonica and its varieties have led to the report of 7 new atisane-type diterpenoids and 38 new diterpene alkaloids of atisine- and hetisine-type1-11. This paper describes the isolation and structure elucidation of two new diterpene alkaloids named spiratines A and B (1-2). Their structures were elucidated on the basis of 1D and 2D NMR experiments (HMQC, HMBC, 1…  相似文献   
960.
1. INTRODUCTION Bioreactors using membranes as substrates of cell cultures have become widely used for hybrid liver support systems [1]. For enhancing and prolonging the metabolism of the bioreactors, cytocompatible membranes are necessary because the cell culture is closely affected by the substrate surface. Surface factors considered to be important in cell culture are the concentration of ionic groups, the nature of polar and non-polar groups and the hydrophilic-hydrophobic balance [2].…  相似文献   
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