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991.
992.
Haitao Han Liang Kan Ping Li Guoshuai Zhang Kaiyue Li Wuping Liao Yunling Liu Wei Chen Chunhua T.Hu 《中国科学:化学(英文版)》2021,(3):426-431
Three 4.8 nm isostructural{M72}(M=CoⅡ for CIAC-128,NiⅡ for CIAC-129,FeⅡ for CIAC-130) metal-organic polyhedra(MOPs) are constructed by eighteen M4-p-tert-butylthiacalix[4]arene (M4-TC4A) units bridged via sixteen four-connected 5,5′-(1H-1,2,4-triazole-3,5-diyl) diisophthalic acid (H4TADIPA) linkers.These MOPs are featured with a rarely reported concave coordination cage,which can be simplified as a squeezed double-decker hexagonal prism pressed from the top and bottom hexagonal faces.Furthermore,CIAC-128,CIAC-129 and CIAC-130 are the highest nuclearity discrete clusters of Co,Ni and Fe reported so far.CIAC-128 has higher separation selectivity of C3H8 than CH4 under ambient conditions,and also exhibits separation selectivity for C2H6/CH4,C2H2/CH4,and C2H4/CH4.In addition,CIAC-128 can provide the cavity for the confined synthesis of noble metal nanoclusters such as Pd nanoclusters and the resulting Pd@CIAC-128 hybrids show higher electrocatalytic activity than commercial Pt/C towards hydrogen evolution reaction (HER). 相似文献
993.
Can Liao Wei Wang Junling Wang Longfei Han Shuilai Qiu Lei Song Zhou Gui Yongchun Kan Yuan Hu 《Journal of Energy Chemistry》2021,(5):1-10
To date,lithium-ion batteries are becoming increasingly significant in the application of portable devices and electrical vehicles,and revolutionary progress in theoretical research and industrial application has been achieved.However,the commercial polyolefin separators with unsatisfying electrolytes affinity and poor thermal stability have extremely restricted the further application of lithium-ion batteries,especially in the high-temperature fields.In this work,magnetron sputtering deposition technique is employed to modify the commercial polyimide separator by coating silicon nitride on both sides.Magnetron sputtering deposition modified polyimide(MSD-PI)composite separator shows high thermal stability and ionic conductivity.More importantly,compared with the cells using Celgard separator,the cells with MSD-PI separator exhibit superior electrochemical performance,especially long-term cycle performance under high temperature environment,owing to the high thermal conductivity of surface Si3 N4 particles.Hence,lithium-ion batteries with MSD-PI separator are capable of improving thermal safety and capacity retention,which demonstrates that magnetron sputtering deposition technique could be regarded as a promising strategy to develop advanced organic/inorganic composite separators for high-temperature lithium-ion batteries. 相似文献
994.
995.
996.
997.
Wei Song Marvin D. Rausch James C. W. Chien 《Journal of polymer science. Part A, Polymer chemistry》1996,34(14):2945-2953
The effect of reaction conditions, including catalyst concentration, temperature, and immobilization on support, have been investigated for syndioselective propylene polymerization by the “bare” zirconocenium ion generated from 1,1-diphenyl-methylidene(1-η5-cyclopentadienyl)(9-η5-fluorenyl)zirconium-dichloride precursor (2). Neither variation of the catalyst concentration nor immobilization of 2 on silica support affect the syndiospecificity of polymerization. The stereoregularity of the syndiotactic polypropylene, as judged from the melting transition temperature and homosteric r-pentad population by 13C-NMR, were found to be proportional to polymer molecular weight. These behaviors are compared with a typical isoselective catalyst ethylenebis(4,5,6,7-tetrahydroindenyl) Zr precursor (4). They are in close resemblance in the case of the S-enantiomeric complex of 4, but the racemic mixture of 4 is markedly inferior. The origins of stereo- and regio-errors are discussed. © 1996 John Wiley & Sons, Inc. 相似文献
998.
Fengfu Li Yingtai Jin Chunlei Song Yonghua Lin Fengkui Pei Fosong Wang Ninghai Hu 《应用有机金属化学》1996,10(10):761-771
Three new lanthanide (Ln)–alkylaluminium (Al) bimetallic complexes with the formula [(μ-CF3CO2)2Ln(μ-CF3CHO2)AlR2 · 2THF]2 (Ln=Nd, Y, R=i-C4H9 (i-Bu); Ln=Eu, R=C2H5(Et); THF=tetrahydrofuran) were synthesized by the reaction of Ln(CF3CO2)3 (Ln=Nd, Y) with HAl (i-Bu)2 and of Eu(CF3CO2)3 with AlEt3, respectively. Their crystal structures were determined by X-ray diffraction at 233 K. [(μ-CF3CO2)2Nd (μ-CF3CHO2)Al(i-Bu)2 · 2THF]2 (Nd–Al) and [(μ-CF3CO2)2Y(μ-CF3CHO2)Al(i- Bu)2 · 2THF]2 (Y–Al) are isomorphous and crystallize in space group P 1 with a =12.441(3) Å [12.347(5) Å for Y–Al], b =12.832(3) Å [12.832(4) Å], c =11.334(3) Å [11.292(8) Å], α=104.93 (2)° [104.45(4)°], β=98.47(2)° [98.81(4)°], γ=64.60(2)° [64.30(3)°], R =0.519 [0.113], R w=0.0532 [0.110], Z =1 and [(μ-CF3CO2)2Eu(CF3 CHO2)AlEt2 · 2THF]2(Eu–Al) in space group P 21/ n with a =11.913(6) Å, b =14.051(9) Å, c =17.920(9) Å, α=101.88(11)°, β=γ=90°, R =0.0509, R w=0.0471 and Z =2. The six CF3CO 相似文献
999.
Effect of Cu Ions on the Dipole Moments and Polarization of Strontium Barium Niobate Single Crystals
H. R. Xia C. J. Wang H. Yu H. C. Chen Y. Y. Song 《Crystal Research and Technology》1996,31(7):889-895
The crystal growth, the ferroelectric hysteresis loops, and the infrared reflectivity spectra of coppermodified strontium barium niobate (SBN) single crystals are reported. Compared with the undoped SBN crystals, the copper-modified crystals have stable hysteresis loops, the spontaneous polarization of which is about 0.30 C/m2, but that of the undoped SBN crystals is only about 0.12 C/m2. Their coercive field strength is all about 340 V/mm. The experimental results of the infrared spectra show that the infrared reflectivities vary as the orientations of the dipole moments owing to the copper-doping. The c-axis becomes the most stable orientation of the dipole moments, and the polarization will be locked and won't recede if the copper-modified crystals are polarized into monodomains. 相似文献
1000.
Li-Zhao Huang Yue Shui Wei Chen Zhong-Ming Li Hong-Tao Song Guang-Ai Sun Jia-Zhuang Xu Gan-Ji Zhong Dong Liu 《高分子科学》2021,39(3):365-376
The correlation between aggregates and bound rubber structures in silicone rubbers(S(phr)) with various silica fractions(ΦSi) has been investigated by contrast matching small-angle neutron scattering(SANS), swelling kinetics, and low-field nuclear magnetic resonance(NMR).Mixed solvents with deuterated cyclohexane fractions of 4.9% and 53.7% were chosen to match the scattering length densities of the matrix(SMP(phr)) and the filler(SMS(phr)), respectively. All the data consistently suggest that:(i) There is a critical threshold ΦSic between 10 and 30 phr;below ΦSic, the isolated aggregates are dominant, while beyond ΦSic, some rubber fraction is trapped among the agglomerate;(ii) ΦSiindependent thicknesses around 7.5 nm(NMR) and 8.6 nm(SANS) suggest that the bound rubber formation is determined by inherent properties of the components, and the power-law around 4.2 suggests an exponential changed gradient density of the bound rubber;(iii) SMS(80) presents a bicontinuous bound rubber with three characteristic lengths of 41, 100, and 234 nm. The expanded correlation length, a 20 nm smaller aggregate sizes suggest that such existent bicontinuous network in dry samples with less ΦSi is kind of impacted by swelling. With the obtained bound rubber models, the reinforcing mechanism of filled silicone rubber is elucidated. 相似文献