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Dr. Fei Wang Yanshuai Bi Kai Hu Dr. Xuejiao Wei 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(21):4874-4879
A catalyst in which Pd nanoparticles are supported on triangle-shaped La2O2CO3 nanosheets exposing predominantly the (001) planes (Pd/La2O2CO3-TNS; where TNS denotes triangular nanosheets) was prepared by a facile solvothermal method. The Pd/La2O2CO3-TNS catalysts exhibited excellent catalytic activity and recycling stability for hydrogenation of cinnamaldehyde to hydrocinnamaldehyde with turnover frequency of up to 41 238 h−1. This enhanced activity of Pd/La2O2CO3-TNS results from strong metal–support interactions. Structure analysis and characterization demonstrated that surface-oxygen-enriched La2O2CO3-TNS supports exposing (001) planes are beneficial to charge transfer between the Pd nanoparticles and triangle-shaped La2O2CO3 nanosheets and increase the electron density of Pd. Moreover, the modulated electronic states of the Pd/La2O2CO3-TNS catalysts can enhance the adsorption and activation of hydrogen to enhance the hydrogenation activity. 相似文献
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The inverse 1-median problem consists in modifying the weights of the customers at minimum cost such that a prespecified supplier becomes the 1-median of modified location problem. A linear time algorithm is first proposed for the inverse problem under weighted l ?? norm. Then two polynomial time algorithms with time complexities O(n log n) and O(n) are given for the problem under weighted bottleneck-Hamming distance, where n is the number of vertices. Finally, the problem under weighted sum-Hamming distance is shown to be equivalent to a 0-1 knapsack problem, and hence is ${\mathcal{NP}}$ -hard. 相似文献
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Electrocatalysis on the degradation of methyl orange is investigated using Sb2O3‐loaded activated carbon (Sb2O3/AC), a new particle electrode. The electrode was prepared by an impregnation method. An orthogonal array with four factors and three levels was selected to carry out the experiment. Electrocatalysis on the degradation of methyl orange through Sb2O3/AC was characterized by a series of parameters, including the amount of the particle electrode, the concentration of Na2SO4, the cell voltage, and the electrolysis time, and the results were compared with those of a conventional AC particle electrode. The results indicate that calcination temperature has the greatest impact on the catalytic activity of the particle electrode. The optimal conditions for preparing the Sb2O3/AC electrode include an 8 mL SbCl3 solution, 90 min hydrolysis time, 400 °C calcination temperature, and 180 min calcination time. As well, the degradation efficiency of the Sb2O3/AC electrode is consistently higher than that of the AC electrode under the same electrolysis conditions. The electrochemical oxidation of methyl orange of both electrodes conformed to pseudo first‐order kinetics, but the rate constant of the Sb2O3/AC electrode was 2.29 times that of the AC electrode; this is likely due to the high electrocatalytic activity of the experimental electrode. The electrocatalysis results exhibited the synergetic effects of AC and Sb2O3 in the new particle electrode. 相似文献
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An inhibitory kinetic fluorimetric method is reported for the determination of trace bisphenol S (BPS). The proposed method is based on the inhibitory effect of BPS on the fluorescence quenching of rhodamine B (RhB) caused by potassium bromate in a dilute phosphoric acid medium. Under the optimal conditions of the experiment, the detection limit for BPS was 0.021 mg/L, and the linear range of determination was from 0.035 mg/L to 0.750 mg/L. The relative standard deviations of 11 measurements for 0.20 mg/L and 0.40 mg/L BPS solutions were 2.74 % and 1.87 %, respectively. The method was successfully applied to the determination of bisphenol S derived from commercially available plastic film samples in hot water. A possible reaction mechanism of the inhibitory effect of BPS on the fluorescence quenching of RhB was proposed. 相似文献
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《Journal of Applied Mathematics and Mechanics》1999,63(5):751-753
The branching of the steady motions of a heavy circular disc on an absolutely rough horizontal plane is investigated. The motions corresponding to critical points of the energy integral at fixed levels of two other integrals having the form of hypergeometric series are considered. 相似文献
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结合省教学示范中心建设经验提出扎根教学目的和实验项目的训练重心对内容体系、教学模式进行改革,另外对于本科生的科研训练也是教学过程的重要一环。 相似文献