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排序方式: 共有146条查询结果,搜索用时 562 毫秒
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The thermal and thermo-elastic-plastic response of newly developed ceramic-metalfunctionally graded materials under a thermal shock load is studied.The materials are heated at the ce-ramic surface with a sudden high-intensity heat flux input,and cooled at the metal surface with aflowing liquid nitrogen.Emphasis is placed on two aspects:(1)the influence of the graded composi-tion of the materials on the temperature and stress response;and(2)the optimum design of the gradedcomposition from a unified viewpoint of the heat insulation property and stress relaxation property.Moreover,a comparison between the thermoelastic stress and the thermo-elastic-plastic stress is alsomade to indicate the plasticity effect. 相似文献
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A new catalyst has been prepared by coprecipitation sedimentation method developed in our laboratory. It exhibits excellent
catalytic activity, selectivity and stability for conversion of synthesis gas to dimethyl ether: conversion of CO 92%, selectivity
of dimethyl ether 98%. Catalytic properties of the catalyst show no evident change after being used for 100 h. 相似文献
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Qingjie Zhao Chunkai Wang Edward L. Ezell Yuxiang Dong Jonathan L. Vennerstrom 《Tetrahedron letters》2014
When praziquantel was exposed to N-bromosuccinimide in the presence of ethanol, a tricyclic 3-bromo-1-ethoxy pyrazinone was formed. From this and the analogous 1,3-dibromopyrazinone, a small library of 3-alkylamino-1-ethoxy, 1,3-dialkoxy, 3-alkoxy-1-bromo, and 3-alkylamino-1-bromo substituted pyrazinones were synthesized in high yields. 相似文献
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Yuan Yongning Yuan Nini Guo Tuo Bai Hongcun Xia Hongqiang Ren Yanjiao Guo Qingjie 《Structural chemistry》2022,33(3):721-731
Structural Chemistry - A detailed theoretical analysis of the mechanism of chemical bond activation in cyclohexane catalysed by the atomic transition-metal cation Ni+ was performed by density... 相似文献
6.
Mei Xiang Qingjie Jiao Yanli Zhu Jinyang Yu Liping Chen 《Journal of Thermal Analysis and Calorimetry》2014,116(3):1159-1163
The thermal behavior of the energetic material 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaaza-tetracyclo-[5.5.0.05,9.03,11]-dodecane (HNIW or CL-20) and its mixtures with aluminum under linear temperature control condition and adiabatic condition were investigated by DSC-TG-MS-FT-IR and ARC. Two different particle sizes of aluminum powder (10 μm and 50 nm) were added into CL-20. The influence of particle size on the thermal behavior of CL-20 was studied by using of these apparatuses. The enthalpies of reaction and onset temperatures were determined for various heating rates. The kinetic parameters were found according to Kissinger method, Ozawa method, and Friedman method based on DSC data. The gaseous products from the decomposition of CL-20 and its mixtures were determined by simultaneous MS-FT-IR experiments. ARC measurements were performed to investigate the thermal stability of the samples. The onset temperature, adiabatic temperature rise, self-heat rate, time to maximum rate, and pressure–temperature profile were found from the data measured by ARC. Based on these results, the catalytic effect of aluminum powder was studied. 相似文献
7.
Synthesis and Catalytic Reactions of Nanoparticles formed by Electrospray Ionization of Coinage Metals
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Anyin Li Qingjie Luo Prof. So‐Jung Park Prof. R. Graham Cooks 《Angewandte Chemie (International ed. in English)》2014,53(12):3147-3150
Noble metals can be ionized by electrochemical corrosion and transported by electrospray ionization. Mass spectrometry (MS) showed solvated metal ions as the main ionic constituent of the sprayed droplets. Collection of the electrospray plume on a surface yielded noble metal nanoparticles (NPs) under ambient conditions. The NPs were characterized by several techniques. Under typical conditions, capped‐nanoparticle sizes averaged 2.2 nm for gold and 6.5 nm for silver. The gold nanoparticles showed high catalytic activity in the reduction of p‐nitrophenol by NaBH4. Efficient catalysis was also observed by simply directing the spray of solvated Au+ onto the surface of an aqueous p‐nitrophenol/NaBH4 mixture. Organometallic ions were generated by spiking ligands into the spray solvent: for example, CuI bipyridine cations dominated the spray during Cu electrocorrosion in acetonitrile containing bipyridine. This organometallic reagent was shown to be effective in the radical polymerization of styrene. 相似文献
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组合催化剂上丙烷选择氧化制丙烯酸 总被引:1,自引:0,他引:1
考察了在C3H8氧化脱氢的NiZrO催化剂和C3H6选择氧化的Mo基催化剂组成的组合催化剂上C3H8选择氧化制取丙烯酸的反应性能.结果表明,两个催化剂比例适当时,反应的丙烯酸收率可达最大.优化温度、烷氧比、空速以及N2含量等反应条件的结果发现,反应体系中O2的匮乏会严重影响反应性能.在有氧分布器的反应装置中对所选组合催化剂在优化的反应条件下进行了30h稳定性测试,结果表明,在340oC,反应性能基本稳定,C3H8转化率和丙烯酸选择性可分别维持在~20%和~74%. 相似文献