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91.
92.
Scientometrics - The spatiotemporal context affects corporate behavior because any corporate activity is carried out in a specific time and space. Based on an examination on the research and... 相似文献
93.
Yuhang Liu Yumeng Zhou Shulin Yang Huoxi Xu Zhigao Lan Juan Xiong Zhao Wang Haoshuang Gu 《International Journal of Hydrogen Energy》2021,46(7):5891-5903
The adsorption of the hydrogen molecule on the pure porous graphene nanosheet (P-G) or the one decorated with Be atom (Be-G) was investigated by the first-principle DFT calculations. The Be atom was adsorbed on the P-G with a binding energy of ?1.287 eV to successfully establish the reasonable Be-G. The P-G was a poor substrate to interact weakly with the H2, whereas the Be-G showed a high affinity to the adsorbed H2 with an enhanced adsorption energy and transferred electrons of ?0.741 eV and 0.11 e, respectively. A molecular dynamics simulation showed that the H2 could also be adsorbed on the Be-G at room temperature with a reasonable adsorption energy of ?0.707 eV. The interaction between the adsorbed H2 and the Be-G was further enhanced with the external electrical fields. The applied electrical field of ?0.4 V/Å was found to be the most effective to enhance the adsorption of H2 on the Be-G with the modified adsorption energy and the improved transferred electrons being ?0.708 eV and 0.17 e, respectively. Our study shows that the Be-G is a promising substrate to interact strongly with the H2 and could be applied as a high-performance hydrogen gas sensor, especially under the external electrical field. 相似文献
94.
Dong Wang Xiaojun Gu Guanwei Liu Guofang Huang Yue Cao Yan Guo 《International Journal of Hydrogen Energy》2021,46(7):5158-5168
Construction of structural defects in photocatalysts is a powerful tool for regulating their photocatalytic performance. In this work, we develop a facile one-step coupling cold plasma and thermal polymerization approach to synthesize a series of nitrogen defect-rich graphitic carbon nitrides (C3N4-x), which are used for visible-light-driven hydrogen generation from water. The nitrogen defect-induced band structure regulation of C3N4-x catalysts can be carried out through controlling the bombardment time and excitation power of generator during the plasma modification process. The defective C3N4-x catalysts have the extended visible light absorption and improved separation efficiency of photogenerated charge carriers, which results in the boosted hydrogen generation activity. Particularly, the optimal C3N4-x possesses a hydrogen generation rate of 2.46 mmol h?1 g?1, which is about 4.5 times higher than the pristine C3N4 synthesized by the single thermal polymerization of urea. The cold plasma modification-based one-step synthesis approach guides us for rationally designing defective nanomaterials with excellent catalytic performance. 相似文献
95.
Porosity is a major issue in solidification processing of metallic materials.In this work,wedge die casting experiments were designed to investigate the effect of cooling rate on microporosity in an aluminum alloy A356.Microstructure information including dendrites and porosity were measured and observed by optical microscopy and X-ray micro-computed tomography(XMCT).The effects of cooling rate on secondary dendrite arm spacing(SDAS)and porosity were discussed.The relationship between SDAS and cooling rate was established and validated using a mathematical model.Three-dimensional(3-D)porosity information,including porosity percentage,pore volume,and pore number,was determined by XMCT.With the cooling rate decreasing from a lower to a higher position of the wedge die,the observed pore number decreases,the porosity percentage increases,and the equivalent pore radius increases.Sphericity of the pores was discussed as an empirical criterion to distinguish the types of porosity.For different cooling rates,the larger the equivalent pore radius is,the lower the sphericity of the pores.This research suggests that XMCT is a useful tool to provide critical 3-D porosity information for integrated computational materials engineering(ICME)design and process optimization of solidification products. 相似文献
96.
Shao-Fang Li Zhen-Yi Gu Jin-Zhi Guo Xian-Kun Hou Xu Yang Bo Zhao Xing-Long Wu 《材料科学技术学报》2021,78(19):176-182
In recent years,sodium-ion batteries(SIBs)have been considered as one of the most promising alterna-tives to lithium-ion batteries(LIBs).Here,a new Na-super-ionic conductor(NASICON)cathode material NaFe2PO4(SO4)2 is successfully prepared through solid state method for SIBs.While the poor electronic conductivity of iron-based materials results in its poor rate and cycle performance.Then the electro-chemical is effectively promoting via Ca2+doping.Na0.84Ca0.08Fe2PO4(SO4)2 have achieved considerable electrochemical properties.The first discharge specific capacity is 121.6mAhg-1 at 25mAg-1 with the voltage platform(~3.1 V)corresponding to Fe2+/3+.After 100 cycles,the capacity retention is 55.1%.The excellent electrochemical performance is caused by some Na+is substituted by Ca2+and leading to the fast sodium kinetics,which is well proved by the powder X-ray diffraction pattern and well corresponding to the galvanostatic intermittent titration technique and cyclic voltammetry testing result(the diffusivity values are around at 10-12 cm2 s-1). 相似文献
97.
Rui-Qi Yao Yi-Tong Zhou Hang Shi Wu-Bin Wan Qing-Hua Zhang Lin Gu Yong-Fu Zhu Zi Wen Xing-You Lang Qing Jiang 《Advanced functional materials》2021,31(10):2009613
Electrocatalytic hydrogen evolution in alkaline and neutral media offers the possibility of adopting platinum-free electrocatalysts for large-scale electrochemical production of pure hydrogen fuel, but most state-of-the-art electrocatalytic materials based on nonprecious transition metals operate at high overpotentials. Here, a monolithic nanoporous multielemental CuAlNiMoFe electrode with electroactive high-entropy CuNiMoFe surface is reported to hold great promise as cost-effective electrocatalyst for hydrogen evolution reaction (HER) in alkaline and neutral media. By virtue of a surface high-entropy alloy composed of dissimilar Cu, Ni, Mo, and Fe metals offering bifunctional electrocatalytic sites with enhanced kinetics for water dissociation and adsorption/desorption of reactive hydrogen intermediates, and hierarchical nanoporous Cu scaffold facilitating electron transfer/mass transport, the nanoporous CuAlNiMoFe electrode exhibits superior nonacidic HER electrocatalysis. It only takes overpotentials as low as ≈240 and ≈183 mV to reach current densities of ≈1840 and ≈100 mA cm−2 in 1 m KOH and pH 7 buffer electrolytes, respectively; ≈46- and ≈14-fold higher than those of ternary CuAlNi electrode with bimetallic Cu–Ni surface alloy. The outstanding electrocatalytic properties make nonprecious multielemental alloys attractive candidates as high-performance nonacidic HER electrocatalytic electrodes in water electrolysis. 相似文献
98.
Wang Ru Sun Qilong Gu Hu Ye Wei Yuan Guoqiu Yang Zhongtian Long Xiaoyun 《Journal of Materials Science: Materials in Electronics》2022,33(3):1383-1394
Journal of Materials Science: Materials in Electronics - A single material with dielectric or magnetic loss behavior cannot optimally absorb electromagnetic waves because such waves are composed of... 相似文献
99.
Applied Intelligence - In this study, we propose a method for object matching between visible and infrared images. We consider object matching between visible and infrared images as a computational... 相似文献
100.
上海中心大厦项目在规划、设计和施工中通过减少对各种资源尤其是不可再生资源的再利用、控制能源能耗、提高室内环境质量以及运用BIM技术等措施,实现了整个工程的精细化管理,已同时获得三星级绿色建筑设计标识证书和LEED金级预认证,是国内超高层首获双认证的摩天大楼。 相似文献