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排序方式: 共有342条查询结果,搜索用时 46 毫秒
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Positivity - This paper is devoted to the study of efficient elements for set-valued maps. We propose two new notions of relative weak $$\epsilon $$ -efficient element and strict relative weak... 相似文献
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Faroughi Niya Homayoun Hazeri Nourallah Fatahpour Maryam Maghsoodlou Malek Taher 《Research on Chemical Intermediates》2020,46(7):3651-3666
Research on Chemical Intermediates - A novel magnetically heterogeneous nanocatalyst has been successfully synthesized via the immobilization of piperazine on tris (hydroxymethyl)... 相似文献
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Abdul Malek Yanrong Xue Xu Lu 《Angewandte Chemie (International ed. in English)》2023,62(40):e202309854
In the pursuit of long-term stability for oxygen evolution reaction (OER) in seawater, retaining the intrinsic catalytic activity is essential but has remained challenging. Herein, we developed a NixCryO electrocatalyst that manifested exceptional OER stability in alkaline condition while improving the activity over time by dynamic self-restructuring. In 1 M KOH, NixCryO required overpotentials of only 270 and 320 mV to achieve current densities of 100 and 500 mA cm−2, respectively, with excellent long-term stability exceeding 475 h at 100 mA cm−2 and 280 h at 500 mA cm−2. The combination of electrochemical measurements and in situ studies revealed that leaching and redistribution of Cr during the prolonged electrolysis resulted in increased electrochemically active surface area. This eventually enhanced the catalyst porosity and improved OER activity. NixCryO was further applied in real seawater from the Red Sea (without purification, 1 M KOH added), envisaging that the dynamically evolving porosity can offset the adverse active site-blocking effect posed by the seawater impurities. Remarkably, NixCryO exhibited stable operation for 2000, 275 and 100 h in seawater at 10, 100 and 500 mA cm−2, respectively. The proposed catalyst and the mechanistic insights represented a step towards realization of non-noble metal-based direct seawater splitting. 相似文献
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Parvaneh Dastoorani Malek Taher Maghsoodlou Mohammad A. Khalilzadeh Santiago García‐Granda Laura Torre‐Fernndez Evan Sarina 《Heteroatom Chemistry》2016,27(2):102-107
An efficient, simple, and diastereoselective synthesis of novel benzofuran phosphonato ester derivatives has been achieved via a one‐pot three‐component reaction of euparin as a natural product, trialkyl phosphate, and dimethyl acetylenedicarboxylate (DMAD) in diethyl ether without using any catalyst at room temperature. NMR spectroscopic data and X‐ray crystallography analysis are in agreement with the anti arrangement for the two vicinal protons in the structures, and only one diastereoisomer (2S,3R) or (2R,3S) was obtained for the products. The advantage of our research is that this is the first report for the diastereoselective synthesis of phosphonato ester derivatives from a green natural product. This one‐pot reaction occurs in high yields with easy work‐up under mild conditions. All pure products were obtained by recrystallization from ethanol, and there was no need for column chromatography. 相似文献
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On existence and multiplicity of similarity solutions to a nonlinear differential equation arising in magnetohydrodynamic Falkner–Skan flow for decelerated flows 下载免费PDF全文
R. Naseri A. Malek R. A. Van Gorder 《Mathematical Methods in the Applied Sciences》2015,38(17):4272-4278
Previously, existence and uniqueness of a class of monotone similarity solutions for a nonlinear differential equation arising in magnetohydrodynamic Falkner–Skan flow were considered in the case of accelerating flows. It was shown that a solution satisfying certain monotonicity properties exists and is unique for the case of accelerated flows and some decelerated flows. In this paper, we show that solutions to the problem can exist for decelerated flows even when the monotonicity conditions do not hold. In particular, these types of solutions have nonmonotone second derivatives and are, hence, a distinct type of solution from those studied previously. By virtue of this result, the present paper demonstrates the existence of an important type of solution for decelerated flows. Importantly, we show that multiple solutions can exist for the case of strongly decelerated flows, and this occurs because of the fact that the solutions do not satisfy the aforementioned monotonicity requirements. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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