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1.
《International Journal of Hydrogen Energy》2019,44(23):11675-11683
The development of cost-effective heterogeneous catalysts for the dehydrogenation of formic acid (FA) is the key challenge for the commercialization of FA as a hydrogen-storage medium. Herein, PdCoNi nanoparticles (NPs) with different element ratios supported on N-doped carbon nanosheets (N-CN) were designed, which exhibit excellent catalytic dehydrogenation performance for FA. Compared with PdCoNi NPs loaded on the carbon nanosheets (CN), the introduction of pyrrolic N to CN induces the formation of ultrafine, monodispersed and amorphous Pd0.6Co0.2Ni0.2 NPs with a size of 1.60 nm, which significantly increases the number of active sites and the instant contact between FA and catalysts. The as-prepared Pd0.6Co0.2Ni0.2/N-CN catalyst shows more than 99% conversion and 100% H2 selectivity at room temperature, with a record-high initial turnover frequency (TOFinitial) of 1249.0 h−1 among non-noble containing Pd-based catalysts, which demonstrates the high potential of Pd0.6Co0.2Ni0.2/N-CN as a practical catalyst for the hydrogen generation from FA. 相似文献
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稳定性能是单层网壳结构设计的主要控制因素,动力稳定是单层网壳稳定性能的重要组成部分.本文利用非线性有限元理论对点支承两向叉简单层网壳在地震荷载作用下的动力稳定性进行了分析.在数值分析过程中,利用比例法调整地震作用的峰值加速度,采用B—R准则判定结构的动力稳定临界荷载.通过分析对点支承两向叉筒单层网壳的动力稳定特性有了较全面的了解. 相似文献
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为应对柔性直流输电在远距离大容量架空线输电领域应用问题,基于钳位双子模块和双晶闸管子模块拓扑构成的两种模块化多电平换流器,设计了串联双极混合直流输电系统,既提高了输电容量,又能缓解单种拓扑能耗较大或直流故障抑制时间较长问题。重点分析了双极混合拓扑在不同直流故障下等值电路和直流故障穿越机理及其抑制特性。最后,在PSCAD/EMTDC仿真环境下搭建双极混合直流输电模型,对系统稳态运行工况和直流故障穿越特性进行了对比研究。仿真结果表明,双极混合系统既体现出灵活多样的稳态运行特性,又具有直流故障穿越与快速恢复能力,较好地适用于远距离大容量架空线路输电应用领域。 相似文献
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Ying Zhao Jun-min Wang Hai-Yan Liu Shu-Tao Gao 《Journal of Inorganic and Organometallic Polymers and Materials》2014,24(6):1027-1031
A new Zn(II) compound, namely {[Zn(atz)(C2O4)0.5]·H2O}n (1 Hatz = 3-amino-1,2,4-triazole), has been synthesized by the hydrothermal reactions of Zn(NO3)2, Hatz and H2C2O4. Single crystal X-ray structure analysis reveals that compound 1 features a 3D porous pillar-layer structure with 6-connected pcu topology. The free water molecules are filled in the 1D channels. Thermal analysis reveals that it can be stable up to 347 °C. Luminescence investigation for 1 reveals that it can be used as a good candidate for sensing of nitrobenzene. 相似文献
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Yanli Dong Pingping Zhou Huimin Liu 《Journal of Inorganic and Organometallic Polymers and Materials》2014,24(5):874-878
A new Cd(II) compound, namely [Cd(pbdc)(e-urea)]n (1 H2pbdc = terephthalic acid, e-urea = ethyleneurea), has been synthesized by urothermal reactions of Cd(NO3)2, and H2pbdc. Single crystal X-ray analysis reveals that it features a three-dimensional framework based on Cd(II)-carboxylate inorganic chains. The coordinated e-urea molecules are filled in the rhombic channels. Thermal analysis reveals that it can be stable up to 350 °C. The CO2 adsorption and luminescent properties of compound 1 were also investigated. 相似文献
8.
TiC-dispersion-strengthened Cu alloys were prepared by a two-step ball-milling (BM) process followed by sparks plasma sintering (SPS), heat treatment and hot rolling in sequence. The two-step BM process is composed of a pre-ball-milling (pre-BM) on both Ti and graphite powders as well as a subsequent homogenizing by BM together with Cu powder. Microstructure evolution analysis was performed to evaluate the effects of BM conditions on the electrical and mechanical properties of Cu-based alloys. The X-ray results revealed that titanium carbide (TiC) formed from Ti and C under high impact energy BM. Moreover, the formation of TiC during the SPS and heat treatment processes was found to more beneficial in enhancing the mechanical properties of alloy. The residual Ti in Cu matrix was found to be the predominant factor lowering the electrical conductivity of Cu–Ti–C alloys. 相似文献
9.
《Vacuum》2013
A titanium carbide (TiC) nanostructured coating and Ti intermediate layer are fabricated on NiTi by plasma immersion ion implantation and deposition (PIII&D) to improve the surface properties. The chemical composition and structure are determined by X-ray diffraction, Auger electron spectroscopy, scanning electron microscopy, and atomic force microscopy. Nano-indentation is used to evaluate the mechanical properties of the thin film and the biological characteristics are assessed by electrochemical measurement and soaking tests in simulated body fluids. Based on the potentiodynamic polarization and Ni release data after the polarization test, the Ti/TiC nanostructure coating has better corrosion resistance compared to the NiTi substrate and there is significantly less Ni ion release from the NiTi substrate into the simulated body fluids than the uncoated NiTi alloy. 相似文献
10.
《Food Control》2015
The study discusses the mobility and distribution of vinclozolin, dichlofluanid, penconazol, captan, quinoxyfen, fluquinconazol, boscalid and pyraclostrobin residues in surface, skin and pulp in red grapes. A lab test was carried out by immersing grapes in solutions with different concentrations of fungicides and for different periods of time; followed by a determination of the fungicide residues by GC-ECD with an additional confirmation by GC-MS. The distribution between surface, skin and pulp of the grapes was also determined. The percentage sorption ranged from 6.4 to 116%. Results showed that sorption values depended on the time that grapes had been in contact with the fungicide solutions, but not on the initial concentration of solutions. Residues were mainly found in skin, with percentages ranging from 53.0 to 88.4% of total residues. In pulp, these values ranged from 9.6 to 41.7%. Pyraclostrobin showed higher penetration than the other compounds.A field test using three new commercial formulations containing pyraclostrobin, boscalid and a mixture of both, was carried out by applying these formulations to a vineyard. When fungicides were applied individually the ratios of the skin/pulp residues were similar to those obtained in lab; whereas when a mixture of both pesticides was sprayed results showed a lower penetration of the fungicides in the grape pulp. 相似文献