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991.
Substituted 4-amino-1,2,4-triazol-3-ones were synthesized from aldehyde hydrazones and azodicarboxylates in the presence of triphenylphosphine. The cascade reaction was conducted in a single step and the procedure is general and efficient. 相似文献
992.
对于HmABn型的共价分子(或离子),本文提出用公式G=V/2-3n计算中心原子A的杂化轨道数,并由此确定对应的杂化轨道类型。该方法简单、直接、有效。 相似文献
993.
在低温液体无损贮存及涨罐研究方面,经常采用一种假设容器内气、液相均为饱和相的热力学模型.这种模型比较符合实际,并能够大大简化容器内的热力学状态,是一种比较常用的热力学模型.文中利用一个5m3低温贮罐进行的液氮无损贮存及涨罐试验,对该热力学模型进行了对比研究,讨论了饱和相热力学模型误差产生的原因,对于无损贮存和涨罐研究具... 相似文献
994.
Junhan Cho Min Su Park Jin Hyun Choi Byung Chul Ji Sung Soo Han Won Seok Lyoo 《Journal of Polymer Science.Polymer Physics》2001,39(15):1778-1783
A novel blend system was prepared by blending organosoluble nitro‐substituted polybenzimidazole (NO2‐PBI) and polyetherimide (PEI) in a cosolvent at a moderate condition. It was shown that the NO2‐PBI/PEI blends not only possess tractable processability owing to the enhanced solubility of NO2‐PBI but also retain the desirable features of unmodified PBI/PEI blends. Apparent miscibility in the blends was observed and attributed to hydrogen‐bonding interactions between N? H groups in NO2‐PBI and carbonyl groups in PEI. It was revealed that the NO2‐PBI/PEI blends phase‐separate upon heating above the glass‐transition temperatures. The observed mixing of NO2‐PBI and PEI in a molecular level, although sustainable only in the glassy region, was shown to lend synergy effects to the physical properties of the blends. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1778–1783, 2001 相似文献
995.
996.
997.
Hai-lin Su ;Shao-long Tang ;Rui-long Wang ;Yi-qing Chen ;Chong Jia ;You-wei Du 《化学物理学报(中文版)》2009,(1):82-86
The effects of magnetic field annealing on the properties of Fe48Co52 alloy nanowire arrays with various interwire distances (Di=30-60 nm) and wire diameters (Dw=22-46 nm) were investigated in detail. It was found that the array's best annealing temperature and crys- talline structure did not show any apparent dependence on the treatment of applying a 3 kOe magnetic field along the wire during the annealing process. For arrays with small Dw or with large Di, the treatment of magnetic field annealing also had no obvious influence on their magnetic performances. However, such a magnetic field annealing constrained the shift of the easy magnetization direction and improved the coercivity and the squareness obviously for arrays with large Dw or with small Di. The difference in the intensity of the effective anisotropic field within the arrays was believed to be responsible for this different variation of the array's magnetic properties after magnetic field annealing. 相似文献
998.
Wei‐Ping Su Mao‐Chun Hong Rong Cao Jia‐Bao Weng Zhong‐Yuan Zhou S. C. Chan Albert 《中国化学》2001,19(9):817-821
The supramolecular silver(I)‐thiolate complex [Ag(μ2‐SC4N2H4)2(SCN)]n has been prepared from the reaction of AgSCN and pyrimidine‐2‐thiol in DMF. X‐ray diffraction analysis shows that the supramolecular structure exhibits one‐dimensional chain through the secondary Ag‐S interactions and the chains are further linked by strong hydrogen bonds to form a three dimensional network. The luminescence effect from the silver‐centered state of S→Ag LMCT in solid state is different from that in solution due to the secondary Ag‐S interactions. 相似文献
999.
1000.
P. Zhao D.S. Liu Y. Zhang Y. Su H.Y. Liu S.J. Li G. Chen 《Solid State Communications》2012,152(12):1061-1066
Using first-principles density functional theory and non-equilibrium Green's function formalism for quantum transport calculation, we have investigated the electronic transport properties of heteronanotubes by joining a zigzag (6,0) carbon nanotube and a zigzag (6,0) boron nitride nanotube with different atomic compositions and joint configurations. Our results show that the atomic composition and joint configuration affect strongly the electronic transport properties. Obvious negative differential resistance behavior and large rectifying behavior are obtained in the heterostructure with certain composition and joint configuration. Moreover, tube length and tube radius can affect strongly the observed NDR and rectifying behaviors. The observed negative differential resistance and rectifying behaviors are explained in terms of the evolution of the transmission spectrum with applied bias combined with molecular projected self-consistent Hamiltonian states analysis. 相似文献