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Yanping Fan Liu Yajun Xiao Qiang Ma Xiaoxin Sun Pengfei Ji Xiaojun 《Acoustical Physics》2020,66(1):16-20
Acoustical Physics - The surface acoustic wave (SAW) sensor has been widely used to measure torque, and the temperature effect on torque sensitivity has been taken into account. However, few... 相似文献
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A novel H ∞ tracking-based decentralized direct adaptive output feedback fuzzy controller is developed for a class of interconnected nonaffine uncertain nonlinear systems in this paper. By virtue of the proper filtering of the observation error dynamics to assure its strictly positive realness, the observer-based decentralized direct adaptive fuzzy control (DAFC) scheme is presented for a class of large-scale nonaffine nonlinear systems by the combination of H ∞ tracking technique, implicit function theorem, a state observer and a fuzzy inference system. The output feedback and adaptation mechanisms for each subsystem depend upon local measurements not only to achieve asymptotical tracking of a reference trajectory but to guarantee arbitrary small attenuation level of the mismatched errors and external disturbances on the tracking error. Simulation results confirm the effectiveness of the proposed decentralized output feedback scheme. 相似文献
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Dr. Xiaoxin Zou Jikai Liu Juan Su Fan Zuo Prof. Jiesheng Chen Prof. Pingyun Feng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(8):2866-2873
A novel dopant‐free TiO2 photocatalyst (Vo.‐TiO2), which is self‐modified by a large number of paramagnetic (single‐electron‐trapped) oxygen vacancies, was prepared by calcining a mixture of a porous amorphous TiO2 precursor, imidazole, and hydrochloric acid at elevated temperature (450 °C) in air. Control experiments demonstrate that the porous TiO2 precursor, imidazole, and hydrochloric acid are all necessary for the formation of Vo.‐TiO2. Although the synthesis of Vo.‐TiO2 originates from such a multicomponent system, this synthetic approach is facile, controllable, and reproducible. X‐ray diffraction, XPS, and EPR spectroscopy reveal that the Vo.‐TiO2 material with a high crystallinity embodies a mass of paramagnetic oxygen vacancies, and is free of other dopant species such as nitrogen and carbon. UV/Vis diffuse‐reflectance spectroscopy and photoelectrochemical measurement demonstrate that Vo.‐TiO2 is a stable visible‐light‐responsive material with photogenerated charge separation efficiency higher than N‐TiO2 and P25 under visible‐light irradiation. The Vo.‐TiO2 material exhibits not only satisfactory thermal‐ and photostability, but also superior photocatalytic activity for H2 evolution (115 μmol h?1 g?1) from water with methanol as sacrificial reagent under visible light (λ>400 nm) irradiation. Furthermore, the effects of reaction temperature, ratio of starting materials (imidazole:TiO2 precursor) and calcination time on the photocatalytic activity and the microstructure of Vo.‐TiO2 were elucidated. 相似文献
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Shide Lv Xiaoxin Han Jian‐Yong Wang Mingyang Zhou Yanwei Wu Li Ma Liwei Niu Wei Gao Jianhua Zhou Wei Hu Yuezhi Cui Jianbin Chen 《Angewandte Chemie (International ed. in English)》2020,59(28):11583-11590
Herein, an environmentally friendly electrochemical approach is reported that takes advantage of the captodative effect and delocalization effect to generate nitrogen‐centered radicals (NCRs). By changing the reaction parameters of the electrode material and feedstock solubility, dearomatization enabled a selective dehydrogenative C?N versus N?N bond formation reaction. Hence, pyrido[1,2‐a]benzimidazole and tetraarylhydrazine frameworks were prepared through a sustainable transition‐metal‐ and exogenous oxidant‐free strategy with broad generality. Bioactivity assays demonstrated that pyrido[1,2‐a]benzimidazoles displayed antimicrobial activity and cytotoxicity against human cancer cells. Compound 21 exhibited good photochemical properties with a large Stokes shift (approximately 130 nm) and was successfully applied to subcellular imaging. A preliminary mechanism investigation and density functional theory (DFT) calculations revealed the possible reaction pathway. 相似文献
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运用光学方法,分析平面波通过无限大介质平板的传输特性,进而分析单层介质窗口的引入对微波传输性能的影响。在S波段微波源上对聚四氟乙烯材料进行了真空环境下的微波放电击穿实验,通过长时间的表面放电,在聚四氟乙烯材料表面出现电痕和电树枝。在100 ns脉冲宽度下,未发生大面积表面放电前,通过光学照相,在介质表面观测到局部放电现象,认为局部放电仍能导致材料表面破坏。作为对比,进行了聚苯乙烯材料的电老化实验,实验结果表明聚苯乙烯材料具有良好的耐电痕、耐电树枝老化特性。 相似文献
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氧气的两电子还原反应(2e-ORR)是绿色、安全的H2O2合成路线. 本工作以Zn2+和2-甲基咪唑合成的沸石型咪唑酸框架-8 (ZIF-8)为前驱体, 通过高温热解炭化, 利用ZIF-8中的锌在高温下的可挥发性, 制备了非金属氮掺杂石墨化多孔碳材料(p-ZIF), 系统考察了ZIF-8热解炭化温度(900、950和1000 ℃)对催化剂结构和2e-ORR催化性能的影响. p-ZIF不仅保留了ZIF-8规整的菱形十二面体形貌, 而且氮含量高, 拥有高的比表面积和多级孔结构. 在酸性条件下的2e-ORR反应中, 三个p-ZIF催化剂均显示了较低的过电位和较低的Tafel斜率, 而且稳定性良好. 其中在H2O2选择性最高的p-ZIF-950催化剂上, 过电位为86 mV, H2O2选择性最高可达89.2%. 在6 h恒电位反应中, p-ZIF-950催化剂能够以87 mmol•gcat-1•h-1的恒定速率产生H2O2. 根据多种表征结果, 推测p-ZIF催化剂的孔径尺寸和石墨N含量是影响其2e-ORR催化性能的主要因素. 相似文献
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