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滑动控制在水下热动力系统中的应用 被引量:1
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作者 罗凯 李佐成 《船舶工程》 CSCD 北大核心 1997年第5期43-45,3,共3页
由于水下开式循环热动力系统的强烈非线性特征及航行器的姿态变化,采用开环方式或线性化控制方法难以满足新型水下武器(如鱼雷)的战术要求。本文对水下开式循环热动力系统做了全面分析,充分利用滑动控制的强鲁棒性,完成了系统模型... 由于水下开式循环热动力系统的强烈非线性特征及航行器的姿态变化,采用开环方式或线性化控制方法难以满足新型水下武器(如鱼雷)的战术要求。本文对水下开式循环热动力系统做了全面分析,充分利用滑动控制的强鲁棒性,完成了系统模型的简化及滑动控制律的设计,并兼顾了中间状态量的交化情况。 展开更多
关键词 水下热动力系统 滑动控制 鱼雷 中间状态量
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High-entropy perovskite oxides: A versatile class of materials for nitrogen reduction reactions
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作者 Kaibin Chu Jingjing Qin +9 位作者 Haiyan Zhu Michiel De Ras Chuang Wang Lei Xiong Longsheng Zhang Nan Zhang Johan A.Martens Johan Hofkens Feili Lai Tianxi Liu 《Science China Materials》 SCIE EI CAS CSCD 2022年第10期2711-2720,共10页
Despite the intense research efforts directed to electrocatalytic nitrogen reduction reaction(eNRR),the NH_(3) yield and selectivity are still not up to the standard of practical application.Here,high-entropy perovski... Despite the intense research efforts directed to electrocatalytic nitrogen reduction reaction(eNRR),the NH_(3) yield and selectivity are still not up to the standard of practical application.Here,high-entropy perovskite oxides with composition Bax(FeCoNiZrY)_(0.2)O_(3−δ)(Bx(FCNZY)_(0.2)(x=0.9,1)are reported as eNRR catalysts.The eNRR activity of high-entropy perovskite oxide is enhanced by changing the nonstoichiometric metal elements at the A-site,thus generating additional oxygen vacancies.The NH_(3) yield and Faraday efficiency for B_(0.9)(FCNZY)_(0.2) are 1.51 and 1.95 times higher than those for B(FCNZY)_(0.2),respectively.The d-band center theory is used to theoretically predict the catalytically active center at the B-site,and as a result,nickel was identified as the catalytic site.The free energy values of the intermediate states in the optimal distal pathway show that the third protonation step(*NNH_(2)→*NNH_(3))is the rate-determining step and that the increase in oxygen vacancies in the high-entropy perovskite contributes to nitrogen adsorption and reduction.This work provides a framework for applying high-entropy structures with active site diversity for electrocatalytic nitrogen fixation. 展开更多
关键词 high entropy PEROVSKITE nitrogen reduction reaction catalytic activity center
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