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排序方式: 共有1017条查询结果,搜索用时 15 毫秒
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磷钼酸四氢三铵的制备及其交换性能臧二乐,梁树权(北京农业大学应用化学系北京100094)(中国院学院化学研究所北京)关键词磷钼酸四氢三铵,制备,离子交换性能通式为M_nXY_(12)O_(40)·pH_2O(其中M为一价阳离子;X为P、As、Si、G... 相似文献
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Jian Ye Yipeng Zang Qingyu Wang Yida Zhang Da Sun Leijie Zhang Gongming Wang Xusheng Zheng Junfa Zhu 《Journal of Energy Chemistry》2021,(5):283-289
Performance breakthrough of electrocatalysts highly relies on the regulation of internal structures and electronic states.In present work,for the first time,we successfully synthesized nitrogen doped FeS2 nanoparticles(N-FeS2)as the electrocatalysts for hydrogen evolution reaction(HER).The band structure and electronic state of FeS2 are modulated by a nitrogen doping strategy,as confirmed by X-ray photoelectron spectroscopy(XPS),X-ray absorption spectroscopy(XAS)and density functional theory(DFT)calculations.Owing to the band structure and electronic state regulation as well as the weakening of H-S interaction,the designed N-FeS2 electrocatalyst exhibits superior catalytic performance with a low overpotential(~126 mV at 10 mA cm-2)and excellent activity stability under alkaline conditions,which is substantially improved as compared with that of the pure FeS2 counterpart.Our work demonstrates that the modulation of electron state and band structure of an electrocatalyst,which can provide a valuable guidance for designing excellent catalysts for hydrogen evolution reaction and beyond. 相似文献
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研究发现,颗粒物质层被匀速推移挤压过程中,所需推移力先以线性规律增加,在某一确定点后,则会以指数规律增加.而颗粒物质是由众多离散颗粒组成的软凝聚态物质,其宏观上反映的是离散颗粒的个体性质和凝聚态物质的集体效应.颗粒与颗粒之间以及颗粒与边界之间的细观尺度接触力链的构成以及演变规律将会直接影响各种宏观受力情况,其摩擦力与挤压力便是力链的主要构成形式.围绕着定量描述细观力链特征,从而揭示力的变化规律这一目标,采用计算机模拟的方法,依照球形颗粒Hertz法向接触理论和Mindlin-Deresiewicz切向接触理论,对重力作用下不同数目的三维等径球体颗粒层的推移情况进行了离散元仿真模拟,量化分析了推移力变化规律、各摩擦力变化规律以及力链分布规律,发现摩擦力与挤压力在颗粒堆积的不同阶段对力链的构成起到了不同的主次作用,使得力链发生强弱演变,从而发现了推移颗粒物质层时推移力的变化规律及原因.这些结果有利于从力链角度揭示颗粒内部和颗粒与各边界之间的受力情况. 相似文献
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A novel electrochemical approach has been proposed to measure the interface potential at the electrode/solution interface based on reconstructing the three‐electrode system of a potentiostat. In this work, the method was investigated both theoretically and experimentally. Mathematical expressions, describing current? potential characteristics, were derived. Zero current potential Ezcp was defined as the potential at which the current is zero based on linear sweep voltammetry, and was determined from the I? E curve to measure the interface potential. The experimental results obtained with the couples Fe(CN)63?/Fe(CN)64? and Co(NH3)63+/Co(NH3)62+ as examples agreed well with the theory. The proposed approach exhibits an excellent performance for measuring the interface potential due to the advantages of rapidity, high stability and accuracy. 相似文献
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The amino-groups of diethylenetriamine were regioselectively protected by trityl groups and then reacted with dihalogenated alkylane to give the terminal N-blocked hexamine derivatives, from which a series of hexamine ligands (5 a-f) were obtained by removing the trityl groups with 5.0 M HCl solution. Alternatively, the hexamine ligands could be also prepared via amidation and reduction reactions. The synthetic routes described here are mild, efficient and easy to handle. 相似文献
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Metabolite identification of the antimalarial piperaquine in vivo using liquid chromatography–high‐resolution mass spectrometry in combination with multiple data‐mining tools in tandem
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Aijuan Yang Meitong Zang Huixiang Liu Peihong Fan Jie Xing 《Biomedical chromatography : BMC》2016,30(8):1324-1330
Artemisinin‐based combination therapy is widely used for the treatment of uncomplicated Plasmodium falciparum malaria, and piperaquine (PQ) is one of important partner drugs. The pharmacokinetics of PQ is characterized by a low clearance and a large volume of distribution; however, metabolism of PQ has not been thoroughly investigated. In this work, the metabolite profiling of PQ in human and rat was studied using liquid chromatography tandem high‐resolution LTQ‐Orbitrap mass spectrometry (HRMS). The biological samples were pretreated by solid‐phase extraction. Data processes were carried out using multiple data‐mining techniques in tandem, i.e., isotope pattern filter followed by mass defect filter. A total of six metabolites (M1–M6) were identified for PQ in human (plasma and urine) and rat (plasma, urine and bile). Three reported metabolites were also found in this study, which included N‐oxidation (M1, M2) and carboxylic products (M3). The subsequent N‐oxidation of M3 resulted in a new metabolite M4 detected in urine and bile samples. A new metabolic pathway N‐dealkylation was found for PQ in human and rat, leading to two new metabolites (M5 and M6). This study demonstrated that LC‐HRMSn in combination with multiple data‐mining techniques in tandem can be a valuable analytical strategy for rapid metabolite profiling of drugs. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
39.
A fluorine-containing polyacrylate emulsion was synthesized by a UV-initiated emulsion polymerization from methyl methacrylate (MMA) and hexafluorobutly methacrylate (HFMA) in the presence of 2-hydroxy-4-(2-hydroxyethoxy)-2-methyl-propiophenone (Irgacure 2959) as a hydrophilic photoinitiator at room temperature. The latex and films were characterized by Fourier transformed infrared (FT-IR) spectrometry, nuclear magnetic resonance (1H-NMR, 19F-NMR) spectrometry, transmission electron microscopy (TEM), recycling gel permeation chromatography (GPC), dynamic light scattering (DLS), and contact angle (CA) analysis, respectively. The effects of photoinitiator and emulsifier concentration on the polymerization were discussed. Compared to the corresponding thermal polymerization, UV-initiated polymerization of the MMA/HFMA emulsion could be accomplished at a much higher speed. The polymerization conversion in UV-initiated polymerization reached 95% within 10 min at an emulsifier concentration of 0.6 wt%, photoinitiator concentration of 0.4 wt%, and monomer concentration of 10 wt%. 相似文献
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