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31.
Xianfeng Chang Chun Zhang Xueliang Dong Wei Zhou Wanqin Jin Zongping Shao Nanping Xu 《Journal of membrane science》2008,316(1-2):128-136
Effects of sintering atmospheres on properties of SrCo0.4Fe0.5Zr0.1O3−δ mixed-conducting membranes were in detail studied in terms of sintering behavior, electrical conductivity and oxygen permeability. The sintering atmospheres were 100% N2, 79% N2–21% O2, 60% N2–40% O2, 40% N2–60% O2, 20% N2–80% O2 and 100% O2 (in vol.%), and the prepared membranes were correspondingly denoted as S-0, S-21, S-40, S-60, S-80 and S-100, respectively. It was found that the properties of membranes were strongly dependent on the sintering atmosphere. As the oxygen partial pressure in the sintering atmosphere (PO2) increased, sintering ability, electrical conductivity and oxygen permeability decreased at first, which was in the order of S-0 > S-21 > S-40. However, as PO2 increased further, sintering ability, electrical conductivity and oxygen permeability increased gradually: S-40 < S-60 < S-80 < S-100. And the S-100 membrane had the best sintering ability, electrical conductivity and oxygen permeability in all membranes. 相似文献
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Identification of tert‐Butyl Cations in Zeolite H‐ZSM‐5: Evidence from NMR Spectroscopy and DFT Calculations 下载免费PDF全文
Dr. Weili Dai Prof.Dr. Chuanming Wang Dr. Xianfeng Yi Prof. Dr. Anmin Zheng Prof. Dr. Landong Li Prof. Dr. Guangjun Wu Prof. Dr. Naijia Guan Prof. Dr. Zaiku Xie Dipl.‐Chem. Michael Dyballa Prof. Dr. Michael Hunger 《Angewandte Chemie (International ed. in English)》2015,54(30):8783-8786
Experimental evidence for the presence of tert‐butyl cations, which are important intermediates in acid‐catalyzed heterogeneous reactions, on solid acids has still not been provided to date. By combining density functional theory (DFT) calculations with 1H/13C magic‐angle‐spinning NMR spectroscopy, the tert‐butyl cation was successfully identified on zeolite H‐ZSM‐5 upon conversion of isobutene by capturing this intermediate with ammonia. 相似文献
34.
Jie Wang Youlong Xu Xiaofei Sun Xifei Li Xianfeng Du 《Journal of Solid State Electrochemistry》2008,12(7-8):947-952
The homogenous coating of poly (3,4-ethylenedioxythiophene) (PEDOT) on carbon nanotubes was realized by using functionalization of single-walled carbon nanotubes (SWNTs) in this study. Consequently, the PEDOT/functionalized SWNTs (PEDOT/F-SWNTs) composites, with size of around 100nm, which is much smaller than that of PEDOT, were prepared by the electrochemical method. Its small granule increased the active/nonactive mass ratio and reduced the ions diffusion length. Therefore, its specific capacitance of the composite was up to 200F g?1, which was remarkably greater than that of PEDOT. Furthermore, the PEDOT/F-SWNTs composites had very rapid charge/discharge ability with specific capacitance of 180F g?1 at scanning rate of 200mV s?1 and 170F g?1 at frequency of 1Hz, which is an important practical advantage. In addition, such composite had a good cycling performance and a wide potential window. 相似文献
35.
Xianfeng Li Pieter Vandezande Ivo F.J. Vankelecom 《Journal of membrane science》2008,320(1-2):143-150
New solvent resistant nanofiltration (SRNF) membranes with polypyrrole (PPy) modified toplayer were prepared on different types support by in situ pyrrole polymerization. The morphology of the membranes was studied by SEM. The PPy modified membranes were applied in the filtration of organic solvents. All the PPy modified membranes showed a very high retention of the negatively charged RB in different solvent systems, comparable to those of the MPF-50 and STARMEM 122 commercial membranes, but at much higher flux. The extended filtration experiment in strong aprotic DMF of PPy modified membranes showed a clearly stable permeability and retention over 30 h. In addition, the PPy modified membranes showed a much higher flux in THF systems than for earlier reported crosslinked poly(imide) membranes. 相似文献
36.
Zhong‐Kun Li Yanying Wei Xue Gao Li Ding Zong Lu Junjie Deng Xianfeng Yang Jürgen Caro Haihui Wang 《Angewandte Chemie (International ed. in English)》2020,59(24):9751-9756
The uncontrolled release of antibiotics and pharmaceuticals into the environment is a worldwide increasing problem. Thus, highly efficient treatment technologies for wastewater are urgently needed. In this work, seven kinds of typical antibiotics (including water and alcohol soluble ones) are successfully separated from the corresponding aqueous and ethanolic solutions using highly regular laminated membranes. Our membranes are assembled with 2–4 μm titanium carbide nanosheets. The solvent permeance through such titanium carbide membrane is one order of magnitude higher than that through most polymeric nanofiltration membranes with similar antibiotics rejection. This high flux is due to the regular two‐dimensional (2D) structure resulting from the large aspect ratio of titanium carbide nanosheets. Moreover, the electrostatic interaction between the surface terminations and the antibiotics also affects the rejection and enhances the antifouling property. Such 2D titanium carbide membranes further broaden the application scope of laminated materials for separation and purification of high value added drugs in academia and industry. 相似文献
37.
Feiguo chen Wei Ge Li Guo Xianfeng He Bo Li Jinghai Li Xipeng Li Xiaowei Wang Xiaolong Yuan 《中国颗粒学报》2009,7(4)
mputing mode. The preliminary applications of this machine in areas of multi-phase flow, molecular dynamics and so on are reported, demonstrating the supercomputer as a paradigm of green computation in new architecture. 相似文献
38.
In this paper, we study positive Toeplitz operators on the Bergman space via their Berezin transforms. Surprisingly we show that the positivity of a Toeplitz operator on the Bergman space is not completely determined by the positivity of the Berezin transform of its symbol. In fact, we show that even if the minimal value of the Berezin transform of a quadratic polynomial of |z| on the unit disk is positive, the Toeplitz operator with the function as the symbol may not be positive. 相似文献
39.
Computational conformal geometry is an inter-disciplinary field between mathematics and computer science. This work introduces the fundamentals of computational conformal geometry, including theoretic foundation, computational algorithms, and engineering applications. Two computational methodologies are emphasized, one is the holomorphic differentials based on Riemann surface theory and the other is surface Ricci flow from geometric analysis. 相似文献
40.