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71.
Lin Jia Hui Yang Jun Deng Junmei Chen Yuan Zhou Pan Ding Leigang Li Na Han Yanguang Li 《中国化学》2019,37(5):497-500
Electrocatalytic carbon dioxide reduction holds great promise for reducing the atmospheric CO2 level and alleviating the energy crisis. High‐performance electrocatalysts are often required in order to lower the high overpotential and expedite the sluggish reaction kinetics of CO2 electroreduction. Copper is a promising candidate metal. However, it usually suffers from the issues of poor stability and low product selectivity. In this work, bimetallic Cu‐Bi is obtained by reducing the microspherical copper bismuthate (CuBi2O4) for selectively catalyzing the CO2 reduction to formate (HCOO–). The bimetallic Cu‐Bi electrocatalyst exhibits high activity and selectivity with the Faradic efficiency over 90% in a wide potential window. A maximum Faradaic efficiency of ~95% is obtained at –0.93 V versus reversible hydrogen electrode. Furthermore, the catalyst shows high stability over 6 h with Faradaic efficiency of ~95%. This study provides an important clue in designing new functional materials for CO2 electroreduction with high activity and selectivity. 相似文献
72.
Chan Sik Cho Na Young Lee Tae‐Jeong Kim Sang Chul Shim 《Journal of heterocyclic chemistry》2004,41(3):423-429
Nitroarenes are reductively cyclized with an array of tetraalkylammonium halides and trialkylarnmonium chlorides in the presence of a catalytic amount of a ruthenium catalyst along with tin(II) chloride dihydrate at 180° to afford the corresponding quinolines in moderate to good yields. The addition of tin(II) chloride dihydrate is necessary for the effective formation of quinolines and toluene is the solvent of choice. A reaction pathway involving initial reduction of nitroarenes to anilines and conversion of alkylammonium halides to alkylamines, alkyl group transfer from alkylamines to anilines to form an imine, dimerization of imine, and heteroannulation is proposed for this catalytic process. 相似文献
73.
74.
With amino acids as model systems, optically active sum frequency generation (OA-SFG) was used to probe the chirality of molecules with a chiral center and an intrinsically achiral chromophore in isotropic solution for the first time. Like that of circular dichroism (CD), the OA-SFG's near electronic resonance originates from the extrachromophoric chiral perturbation on the carboxyl chromophore. The difference in the relative strengths of OA-SFG and CD among different amino acids can be explained by the difference in the details of perturbations. 相似文献
75.
Wei Xiang Qi‐Shi Song Hong‐Jie Zhang Rong‐Tao Li Zhi Na Han‐Dong Sun 《Helvetica chimica acta》2004,87(11):2842-2847
A new ursane‐type nortriterpenoid, adenanthusone (=(11α,12α)‐4‐demethyl‐11,12‐epoxy‐3,13‐dihydroxy‐2‐oxoursa‐3,20(30)‐diene‐28‐oic acid γ‐lactone; 1 ) was isolated from Isodon adenanthus. Its structure was determined by NMR spectra and X‐ray crystallographic diffraction analysis. The biogenetic implication of the nortriterpene is discussed. 相似文献
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77.
Determination of proteins with Alizarin Red S by Rayleigh light scattering technique 总被引:1,自引:0,他引:1
A new protein determination method by enhanced Rayleigh light scattering (RLS) technique has been developed. In acid condition (pH=3.60), RLS of 1,2-dihydroxyanthraquinone-3-sulfonate (Alizarin Red S) can be greatly enhanced by addition of proteins, resulting in two characteristic peaks, 360 and 505 nm, respectively. The new protein assay is based on the RLS enhancement and spectrum change. The optimum condition for the reaction was investigated. The linear range is 0.20-24.9 μg ml−1 for BSA and 0.20-15.5 μg ml−1 for HSA. The detection limits (S/N=3) are 9.59 ng ml−1 for BSA and 9.51 ng ml−1 for HSA. The results of determination for human serum samples were comparable to those obtained by Bradford method. The binding stoichiometry was determined. 相似文献
78.
A new activation method has been developed for electroless copper plating on silicon wafer based on palladium chemisorption on SAMs of APTS without SnCl2 sensitization and roughening condition.A closely packed electroless copper film with strong adhesion is successfully formed by AFM observation.XPS study indicates that palladium chemisorption occurred via palladium chloride bonding to the pendant amino group of the SAMs. 相似文献
79.
提出了一种新的基于支持向量机(SVM)学习机制的注意力相关脑电分类算法.在对脑电信号进行3级小波分解之后,采用主分量分析方法提取主要的特征分量,并且采用SVM方法对其进行分类.在此基础上,依据数据融合理论,对多导分类结果进行综合判断.结果表明,本方法具有良好的鲁棒性,对注意力相关脑电信号分类的准确率可达89%左右,高于单导最优准确率.该方法对注意力缺陷反馈治疗、注意力机制研究等具有较高的实用价值. 相似文献
80.