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1.
Zhihong Zhao Bin Wang Rui Tan Wenjing Liu Minghui Zhang 《Magnetic resonance in chemistry : MRC》2022,60(4):427-433
In this study, the transverse relaxation time (T2) of activated carbon (AC) in different relative environment humidity was detected firstly by low-field nuclear magnetic resonance (LFNMR). The pore size (diameter) of AC distributions was calculated by the relationship between T2 and surface relaxation rate (ρ), where ρ was obtained by the detection of nine porous materials with known pore size. The results showed that the pore size distributions of AC calculated by ρ < 0.19 nm/ms were in good agreement with that obtained by nitrogen adsorption method and proved that LFNMR as a new detection method was feasible for characterizing AC pore size distribution. 相似文献
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Rongrong Li Hongjie Peng Qingping Wu Xuejun Zhou Jiang He Hangjia Shen Minghui Yang Chilin Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(29):12227-12236
Herein, we propose the construction of a sandwich-structured host filled with continuous 2D catalysis–conduction interfaces. This MoN-C-MoN trilayer architecture causes the strong conformal adsorption of S/Li2Sx and its high-efficiency conversion on the two-sided nitride polar surfaces, which are supplied with high-flux electron transfer from the buried carbon interlayer. The 3D self-assembly of these 2D sandwich structures further reinforces the interconnection of conductive and catalytic networks. The maximized exposure of adsorptive/catalytic planes endows the MoN-C@S electrode with excellent cycling stability and high rate performance even under high S loading and low host surface area. The high conductivity of this trilayer texture does not compromise the capacity retention after the S content is increased. Such a job-synergistic mode between catalytic and conductive functions guarantees the homogeneous deposition of S/Li2Sx, and avoids thick and devitalized accumulation (electrode passivation) even after high-rate and long-term cycling. 相似文献
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The stable phase equilibria of quaternary systems LiBr-NaBr-MgBr2-H2O and LiBr-KBr-MgBr2-H2O at 298.15 K were studied by both experimental measurement(isothermal solution saturation method) and theoretical prediction(Pitzer model). The solubilities of the saturated solution have been determined experimentally and two stable phase diagrams and relevant water diagrams of the two quaternary systems were obtained. Results show that quaternary system LiBr-NaBr-MgBr2-H2O is hydrate II type as NaBr and NaBr·2H2O coexistence. Its phase diagram consists of only one invariant point, four univariant curves, and five crystallization fields. The quaternary system LiBr-KBr-MgBr2-H2O is a complex type as the double salt KBr·MgBr2·6H2O formed. In addition to this double salt, the three single salts LiBr·2H2O, KBr and MgBr2·6H2O also crystallize. In this paper, the solubilities of phase equilibria in above quaternary systems were also calculated by the Pitzer's electrolyte solution model. All the needed parameters can be obtained from the literature or be fitted by experimental data. On the Basis of the experimental and calculated results, the phase diagram of the quaternary system was plotted for comparison. It shows that the calculation results are consistent with the experimental ones. 相似文献
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ZHU Yabin ZHOU Yueliang LIU Zhen WANG Shufang CHEN Zhenghao U Huibin YANG Guozhen XlAO Ling Ren Hongtao JIAO Yulei Zheng Minghui 《中国科学G辑(英文版)》2004,47(2):165-172
The irreversibility field (Hirr) of Y-based superconductor is much higher than that of Bi-based superconductor. Y-based superconductor is capable of maintaining stable electrical currents in high magnetic field and electric field, so it is a better suited mate-rial for electric-current applications. Commonly, the Y-based tapes comprise a YBCO thick film deposited on a flexible substrate, typically with an intermediate buffer layer, and an overcoat of noble metal. In this process, the interm… 相似文献
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The catalytic activities of SO42-/TiO2-MoO3 in synthesizing cyclohexanone ethylene ketal,cyclohexanone 1,2-propanediol ketal, 2-propyl-1,3-dioxolane, 4-methyl-2-isopropyl-1,3-dioxolane,2-isopropyl-1,3-dioxolane, 4-methyl-2-isopropyl-1,3-dioxolane, butanone ethy-lene ketal and butanone 1,2-propanediol ketal were reported. It has been demonstrated that SO42-/TiO2-MoO3 is an excellent catalyst. Various factors concerned in this reaction have been investigated. The optimum conditions have been found, that is, the molar ratio of aldehyde/ketone to alcohol was 1:1.5 or 1:1.3,the mass ratio of the catalyst used to the reactants was 0.25~1.5%, and the reaction time was 45~60 min. Under this conditions, the yield of cyclohexanone ethylene ketal is 82.7%, cyclohexanone 1,2-propanediol ketal is 83.4%, the yield of 2-propyl-1,3-dioxolane is 68.1%,4-methyl-2-isopropyl-1,3-dioxolane is 87.5%, the yield of 2-isopropyl-1,3-dioxolane is 70.7%,4-methyl-2-isopropyl-1,3-dioxolane is 82.5%, the yield of butanone ethylene ketal is 74.1%, and butanone 1,2-propanediol ketal is 94.9%.Some equation and experiment results concerned of the synthetic acetals or ketals were listed as follows. 相似文献