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82.
Wei Yan Wen Wu Kai Wang Zhenghua Tang Shaowei Chen 《International Journal of Hydrogen Energy》2018,43(36):17132-17141
Oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) are two important processes for electrochemical energy storage and conversion. Herein, we describe the preparation of carbon-supported Pd nanocubes@Mo core@shell nanostructures as efficient dual catalysts for both ORR and HER. The core@shell structure was manifested by high-resolution transmission electron microscopy measurements, including high angle-angular dark field-scanning transmission electron microscopy and elemental mapping analysis. Further structural insights were obtained in X-ray diffraction and X-ray photoelectron spectroscopy measurements. The nanostructures exhibited apparent electrocatalytic activity toward both ORR and HER, and the performances were markedly higher than those without the deposition of a Mo overlayer. In ORR, the activity was even better than that of commercial Pt/C within the context of onset potential, specific and mass activities; whereas in HER, the performance of Pd nanocubes@Mo core@shell nanostructures remained subpar as compared to that of Pt/C in terms of the overpotential to reach the current density of 10 mA cm?2, the Tafel slope was comparable and the stability was excellent. The excellent electrocatalytic performance can be attributed to the Pd-Mo synergistic effects imparted from the core-shell structure. 相似文献
85.
Jianming Zhu Dr. Jing Wang Kai Cheng Hui Chen Dr. Ran An Dr. Yaping Zhang Prof. Makoto Komiyama Prof. Xingguo Liang 《Chembiochem : a European journal of chemical biology》2020,21(6):785-788
High-resolution melting (HRM) analysis has been improved and applied for the first time to quantitative analysis of enzymatic reactions. By using the relative ratios of peak intensities of substrates and products, the quantitativity of conventional HRM analysis has been improved to allow detailed kinetic analysis. As an example, the ligation of sticky ends through the action of T4 DNA ligase has been kinetically analyzed, with comprehensive data on substrate specificity and other properties having been obtained. For the first time, the kinetic parameters (kobs and apparent Km) of sticky-end ligation were obtained for both fully matched and mismatched sticky ends. The effect of ATP concentration on sticky-end ligation was also investigated. The improved HRM method should also be applicable to versatile DNA-transforming enzymes, because the only requirement is that the products have Tm values different enough from the substrates. 相似文献
86.
采用热重分析法研究了不同热解条件下半焦的燃烧性能和动力学特征,利用Ozawa法求取动力学参数。结果表明,热解温度越低、保温时间越短时,半焦的燃烧性能越好;热解升温速率对半焦燃烧过程的反应程度影响不大;粒度越大,燃烧性能差异性越明显。热解温度对半焦燃烧性能影响较大,550℃是本研究中制备高燃烧反应性半焦的适宜热解温度。两种不同粒度原煤制得的半焦均随转化率增大,活化能减小。1~3 mm原煤在热解温度为550℃时所得半焦在燃烧过程中符合反应级数模型,化学反应为限制性环节,反应最概然机理函数为f(α)=(1–α)2。 相似文献
87.
运用计算流体力学方法,采用ANSYS CFX软件对发夹式换热器的壳侧流场进行了三维数值模拟。流场计算中采用多孔介质模型对管束区域进行简化,分析了壳侧流场的速度分布,结果表明:直管段部分的流体湍流强度大于弯管段,且外层管束所在区域为高流速区,受流体冲刷严重。结合流场信息,通过功率谱生成随机激振力,采用ABAQUS软件模拟计算了湍流激振下管束的振动响应,结果显示管束的面外均方根位移远大于面内位移,且弯管部分的振动位移最大。该研究结果可为发夹式换热器的性能分析和优化设计提供参考和依据。 相似文献
88.
89.
SINOPEC Turbo Oil1航空润滑油与Mobil Jet OilⅡ航空润滑油的相容性及国产化路径 总被引:1,自引:0,他引:1
90.
Effects of particle size and dispersion methods of In2O3‐SnO2 mixed powders on the sintering properties of indium tin oxide ceramics 下载免费PDF全文
Fangsheng Mei Tiechui Yuan Ruidi Li Libo Zhou Kai Qin 《International Journal of Applied Ceramic Technology》2018,15(1):89-100
Three group samples were used to investigate the effects of particle size and dispersion methods of In2O3‐SnO2 mixed powders on the sintering properties of ITO ceramics by BET, SEM, XRD, and EPMA, etc. High‐density (99.8% of TD) ITO ceramics, with dimensions of 350 × 250 × 8 mm3 for the industrial application, were obtained by the mixed powders of In2O3 calcined at 1000°C and SnO2 with BET 6.0 ± 0.5 m2/g and collocation use of ball mill for 300 minutes, stirred mill for 60 minutes, and sand mill for 3 minutes. The results indicate that: (i) the larger the SnO2/In2O3 particle size ratio, the higher the density of ITO ceramics, (ii) the dispersion of mechanical ball‐mill methods for nanosized In2O3 and SnO2 powders is beneficial to the densification and structural homogeneity, and (iii) the smaller the relative grain size, the more uniform the distribution of grain size. 相似文献