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81.
Jianguo Zhang Zhimin Li Junwei Liu Tonglai Zhang Xiaoqing Niu Chunchun Chen Li Yang Kaibei Yu 《中国化学》2011,29(5):913-918
A novel 3‐dimensional potassium supermolecular compound [K(HDNR)(H2DNR)(H2O)]n (H2DNR?2,4‐dinitro resorcinol) was synthesized and characterized by elemental analysis and FT‐IR spectroscopy. The crystal structure investigated by X‐ray single crystal diffraction shows that [K(HDNR)(H2DNR)(H2O)]n crystallizes with a monoclinic unit cell in the space group P2(1)/c with unit cell dimensions of a=17.648(5) Å, b=12.527(3) Å, c=7.735(2) Å, β=94.33(2)°, V=1705.00(73) Å3, Z=4. The structure was refined to the final R=0.0670 and wR=0.0722 for 2022 observed reflections with I>2σ(I). In the compound, potassium cation is assembled into one‐dimensional chains along c‐axis through oxygen atoms from water molecules, and the chains were connected by the bridged HDNR? anions to form a two‐dimensional net structure. The two‐dimensional nets constructed a three‐dimensional supramolecular architecture via intermolecular hydrogen bonds and N–O···π interaction. Density functional theory (DFT) B3LYP was employed to optimize the structure and calculate energies for three tautomers of HDNR? univalent anion. Three stable tautomers were located. It was found that the structure (I) with O(1) losing hydrogen atom is more stable than the structure (II) also with O(1) losing hydrogen atom and the structure (III) with O(4) losing hydrogen atom. 相似文献
82.
We examine the model-building issue related to multi-objective estimation of distribution algorithms (MOEDAs) and show that some of their, as yet overlooked, characteristics render most current MOEDAs unviable when addressing optimization problems with many objectives. We propose a novel model-building growing neural gas (MB-GNG) network that is specially devised for properly dealing with that issue and therefore yields a better performance. Experiments are conducted in order to show from an empirical point of view the advantages of the new algorithm. 相似文献
83.
Most previous investigations on interference effects of tall buildings under wind actions focused on the wind induced interference effects between two buildings,and the interference effects of three or more buildings have seldom been studied so far due to the huge workload involved in experiments and data processing.In this paper,mean and dynamic force/response interference effects and peak wind pressure interference effects of two and three tall buildings,especially the three-building configuration,are investigated through a series of wind tunnel tests on typical tall building models using high frequency force balance technique and wind pressure measurements.Furthermore,the present paper focuses on the effects of parameters,including breadth ratio and height ratio of the buildings and terrain category,on the interference factors and derives relevant regression results for the interference factors. 相似文献
84.
建筑结构的力学分析都是通过建立计算简图及计算模型进行的, 探讨了
建筑结构计算简图及计算模型的概念、建立计算简图的原则、对实际建筑结构进行简化的内
容, 并介绍了5种实际建筑结构简化的结果, 期望能帮助学生做好结构分析. 相似文献
85.
Jianbei An 《Advances in Mathematics》2011,227(3):1165
We classify controlled blocks, introduced by Alperin and Broué in 1979 for all quasisimple groups G for odd primes. The results imply that every nilpotent block of G has abelian defect groups, which in turn is one of the main results proved in An and Eaton (2011) [6]. We also give an explicit characterization of non-controlled blocks of all quasisimple groups G for odd primes. This implies the block theoretic analogue of Glauberman?s ZJ-theorem for G proved by Kessar, Linckelmann and Robinson (2002) [18]. 相似文献
86.
Shuxiang Yu 《Annals of Differential Equations》2011,(4):505-508
In this paper,using the notion of an isolating block and Conley's attractor theory,an existence criterion of trajectories connecting a pair of invariant sets of ordinary differential equations is given. 相似文献
87.
88.
本文在自共轭的条件下,找到了群G2×Gp(p为奇素数)中相对于2阶子群的(2a-1pb,2a c-1/2 pb/2,2c)-BS的一种下降构造法和一种嵌套构造法,同时给出了Gp的一个指数界,特别地当G2(?) Z2a×Z2a2时,有a2=a1且c=1或2,或者a2=a1-1且c=1. 相似文献
89.
90.