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951.
正Metal-organic frameworks,MOFs,are coordination networks with organic ligands and voids.At the fundamental level,MOFs epitomize the beauty of chemical structures and the power of combining organic and inorganic chemistry,two disciplines that are often regarded as disparate.MOFs have recently emerged as an extensive class of crystalline materials with ultrahigh porosity and internal surface 相似文献
952.
953.
Ling Zhang Dafeng Zuo 《Communications in Nonlinear Science & Numerical Simulation》2013,18(2):257-263
In this paper, we construct Lax pairs and super-bihamiltonian structures of two supersymmetric integrable hierarchies related to a given super-HS spectral problem. 相似文献
954.
Weiwei Zuo Min Zhang Wen‐Hua Sun 《Journal of polymer science. Part A, Polymer chemistry》2009,47(2):357-372
A series of imino‐indolate half‐titanocene chlorides, Cp′Ti(L)Cl2 ( C1 – C7 : Cp′ = C5H5, MeC5H4, C5Me5, L = imino‐indolate ligand), were synthesized by the reaction of Cp′TiCl3 with sodium imino‐indolates. All complexes were characterized by elemental analysis, 1H and 13C NMR spectroscopy. Moreover, the molecular structures of two representative complexes C4 and C6 were confirmed by single crystal X‐ray diffraction analysis. On activation with methylaluminoxane (MAO), these complexes showed good catalytic activities for ethylene polymerization (up to 7.68 × 106 g/mol(Ti)·h) and ethylene/1‐hexene copolymerization (up to 8.32 × 106 g/mol(Ti)·h), producing polyolefins with high molecular weights (for polyethylene up to 1808 kg/mol, and for poly(ethylen‐co‐1‐hexene) up to 3290 kg/mol). Half‐titanocenes containing ligands with alkyl substituents showed higher catalytic activities, whereas the half‐titanocenes bearing methyl substituents on the cyclopentadienyl groups showed lower productivities, but produced polymers with higher molecular weights. Moreover, the copolymerization of ethylene and methyl 10‐undecenoate was demonstrated using the C1 /MAO catalytic system. The functionalized polyolefins obtained contained about 1 mol % of methyl 10‐undecenoate units and were fully characterized by several techniques such as FT‐IR, 1H NMR, 13C NMR, DSC, TGA and GPC analyses. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 357–372, 2009 相似文献
955.
Lei Li Yudong Zhang Claude Esling Zhihao Zhao Yubo Zuo Haitao Zhang Jianzhong Cui 《Journal of Crystal Growth》2009,311(11):3211-3215
Al–0.24 wt%Fe was semi-continuously cast with the application of static magnetic field of 0.1 and 0.2 T. The magnetic field transfers the microstructure from the columnar grains growing in the 〈1 0 0〉 direction into twinned lamellar crystals growing in the 〈1 1 0〉 direction. The lamellas possess the morphology and the crystallographic growth direction of the “feathery crystals”. However, the “feathers” (secondary arms) that branch off the twinning plane only start to form at 0.2 T. Under the two strengths of the magnetic field applied, no side arms in the twinning planes were observed. The increase of the lamellar spacing with the magnetic field is due to the initiation of the secondary arms. 相似文献
956.
通过高温高压法,利用高压釜装置一步合成Al-交联剂,通过离子交换法制备大比表面积、大孔径的Al柱撑粘土(Al-PILC)。研究了稀土铈改性的Al-PILC负载锰氧化物用于氯苯的催化降解的活性。表征结果表明:柱撑后得到的Al-PILC,其比表面积和孔体积达到182.3m2·g-1和0.121 cm3·g-1,远大于原土的2.81 m2·g-1和0.00786 cm3·g-1。Al-PILC的层间距由原土的1.18增大到1.79 nm。活性数据表明:柱撑改性后的Al-PILC负载锰催化剂的活性远大于Na-mmt的,并且添加稀土Ce有利于改善催化剂的氧化性能,进而提高催化剂的活性。10%Mn-6%Ce/Al-PILC催化剂在330℃左右就能催化降解低浓度的氯苯,无Cl2二次污染产生,并且表现出最佳的稳定性。 相似文献
957.
Ke-Jia Zhang Ying Sun Ting-Ting Song Hui-Juan Zuo 《International Journal of Theoretical Physics》2013,52(11):4163-4173
Recently, the researches of quantum group signature (QGS) have attracted a lot of attentions and some typical protocols have been designed for e-payment system, e-government, e-business, etc. In this paper, we analyze the security of the quantum group signature with the example of two novel protocols. It can be seen that both of them cannot be implemented securely since the arbitrator cannot solve the disputes fairly. In order to show that, some possible attack strategies, which can be used by the malicious participants, are proposed. Moreover, the further discussions of QGS are presented finally, including some insecurity factors and improved ideas. 相似文献
958.
Optical matching layer structures in evanescent coupling photodiodes at a wavelength of 1.55μm: physics,design and simulation
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We have studied the optical matching layers (OMLs) and external
quantum efficiency in the evanescent coupling photodiodes (ECPDs)
integrating a diluted waveguide as a fibre-to-waveguide coupler, by
using the semi-vectorial beam propagation method (BPM). The physical
basis of OML has been identified, thereby a general designing rule
of OML is developed in such a kind of photodiode. In addition, the
external quantum efficiency and the polarization sensitivity versus
the absorption and coupling length are analysed. With an optical
matching layer, the absorption medium with a length of 30μm
could absorb 90% of the incident light at 1.55μm
wavelength, thus the total absorption increases more than 7 times
over that of the photodiode without any optical matching layer. 相似文献
959.
Isospin- and momentum-dependent interaction in isospin-dependent quantum molecular dynamics 总被引:1,自引:0,他引:1
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An isospin-dependent quantum molecular dynamical model (IQMD) is developed, with the
isospin degree of freedom in the momentum-dependent interaction(MDI) included in
IQMD, to obtain an isospin- and momentum-dependent interaction (IMDI) in IQMD. We
investigate the effect of IMDI on the isospin fractionation ratio and its dynamical
mechanism in the intermediate energy heavy ion collisions. It is found that the IMDI
induces the significant reductions in the isospin fractionation ratio for all of
beam energies, impact parameters, neutron--proton ratios and mass number of
colliding systems. However, the strong dependence of isospin fractionation ratio on
the symmetrical potential is preserved, with the isospin degree of freedom included
in the MDI, i.e. the isospin fractionation ratio is still a good probe for
extracting the information about the equation of state of isospin asymmetrical
nuclear matter. 相似文献
960.