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91.
This paper solves the problem of adaptive fault-tolerant control of uncertain switched nonlinear systems with unknown parameters and actuator failures. Based on the multi-Lyapunov function method, a novel adaptive switched controller with tuning function is designed using the backstepping procedure. Meanwhile, a switched fault-tolerant adaptation mechanism is also given to compensate the fault efficiency. Furthermore, it is certificated that all the signals of the closed-loop system are uniformly bounded and the tracking error restrain to a small neighbor. Finally, the simulation results verify the feasibility of the proposed method. 相似文献
92.
93.
近年来,盐城德隆镍业厂区附近数次发生输电线路外绝缘放电、污闪现象,且采用复合绝缘子后仍不能得到有效抑制,而临近的化工区却没无该情况发生。因此,本文对盐城电网辖区内镍厂、化工厂绝缘子进行污秽取样,开展了污秽化学成分分析测试,包括阴阳离子含量、不溶物元素组成、主要化合物成分等;继而基于成分分析结果,开展了混合污秽下的污闪特性试验,得到了不同污染源典型污秽成分下复合绝缘子的闪络特性。研究结果表明:化工厂和镍厂附近绝缘子污秽成分有一定的差异,体现在镍厂污秽成分含硝酸盐较多,而化工厂附近含氯盐较多;对于一大两小型复合绝缘子,其在镍厂典型污秽下的闪络梯度要比化工厂低5%-10%;对于重工业粉尘地区的外绝缘配置,建议采用一大一小型绝缘子来提高电气强度。 相似文献
94.
Chao Wang Xiangming Li Liang Wang Guifang Liu Bangbang Nie Yangfan Qiu Bin Fan Chao Yan Xiaoliang Chen Hongmiao Tian Chunhui Wang Jinyou Shao 《Advanced functional materials》2022,32(1):2109265
Metal micropatterns play critical roles in flexible electronics. However, the lack of versatile strategies for micropatterning of diverse metal materials on various thin, flexible or stretchable substrates has limited the rapid development of flexible electronics. Here, a metal micropatterning method by triboelectric spark discharge under atmospheric environment is developed, where a triboelectric nanogenerator (TENG) is employed to precisely and safely control the voltage, current, and frequency of the spark discharges. Micropatterns of metal films like gold, silver, copper, aluminum and platinum are successfully fabricated on substrates of polyimide, polyethylene terephthalate, polyvinyl chloride, polydimethylsiloxane, paper or latex, even on ultrathin substrates (5 μm thick) without damage, where the feature sizes of metal patterns are controllable from 20 μm to 1 mm. Experimental insights into the triboelectric spark discharge behaviors and the pattern feature sizes control are discussed. A straightforward fabrication of metal patterns on the balloon surface or human skin through “handwriting” by a pencil as discharge electrode is realized. Besides metals, extended processibility of conductive materials like carbon nanotubes, graphene, MXene, graphite, carbon fibers, and conductive polymers are also demonstrated. This work proves the possibility of microfabrication by TENG, which is of simplicity and attractiveness for flexible electronics. 相似文献
95.
Yuan Chenxi Li Guoyan Kamarthi Sagar Jin Xiaoning Moghaddam Mohsen 《Journal of Intelligent Manufacturing》2022,33(2):425-439
Journal of Intelligent Manufacturing - In recent years, driven by Industry 4.0 wave, academic research has focused on the science, engineering, and enabling technologies for intelligent and cyber... 相似文献
96.
Sheng Bao Wenzhong Shi Wenzheng Fan Pengxin Chen Mingyan Nie Haodong Xiang 《The Journal of supercomputing》2022,78(2):1903-1922
The Journal of Supercomputing - High-precision point cloud maps have drawn increasing attention due to their wide range of applications. In recent decades, point cloud maps are normally generated... 相似文献
97.
Surface Energy and Surface Stability of Ag Nanocrystals at Elevated Temperatures and Their Dominance in Sublimation‐Induced Shape Evolution 下载免费PDF全文
Long‐Bing He Lei Zhang Xiao‐Dong Tan Lu‐Ping Tang Tao Xu Yi‐Long Zhou Zhan‐Yong Ren Yun Wang Chun‐Yu Teng Li‐Tao Sun Jian‐Feng Nie 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(27)
The surface energy and surface stability of Ag nanocrystals (NCs) are under debate because the measurable values of the surface energy are very inconsistent, and the indices of the observed thermally stable surfaces are apparently in conflict. To clarify this issue, a transmission electron microscope is used to investigate these problems in situ with elaborately designed carbon‐shell‐capsulated Ag NCs. It is demonstrated that the {111} surfaces are still thermally stable at elevated temperatures, and the victory of the formation of {110} surfaces over {111} surfaces on the Ag NCs during sublimation is due to the special crystal geometry. It is found that the Ag NCs behave as quasiliquids during sublimation, and the cubic NCs represent a featured shape evolution, which is codetermined by both the wetting equilibrium at the Ag–C interface and the relaxation of the system surface energy. Small Ag NCs (≈10 nm) no longer maintain the wetting equilibrium observed in larger Ag NCs, and the crystal orientations of ultrafine Ag NCs (≈6 nm) can rotate to achieve further shape relaxation. Using sublimation kinetics, the mean surface energy of Ag NCs at 1073 K is calculated to be 1.1–1.3 J m?2. 相似文献
98.
Imparting Designer Biorecognition Functionality to Metal–Organic Frameworks by a DNA‐Mediated Surface Engineering Strategy 下载免费PDF全文
Weiyu Ning Zhenghan Di Yingjie Yu Pingmei Zeng Chunzhi Di Daquan Chen Xueqian Kong Guangjun Nie Yuliang Zhao Lele Li 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(11)
Surface functionality is an essential component for processing and application of metal–organic frameworks (MOFs). A simple and cost‐effective strategy for DNA‐mediated surface engineering of zirconium‐based nanoscale MOFs (NMOFs) is presented, capable of endowing them with specific molecular recognition properties and thus expanding their potential for applications in nanotechnology and biotechnology. It is shown that efficient immobilization of functional DNA on NMOFs can be achieved via surface coordination chemistry. With this strategy, it is demonstrated that such porphyrin‐based NMOFs can be modified with a DNA aptamer for targeting specific cancer cells. Furthermore, the DNA–NMOFs can facilitate the delivery of therapeutic DNA (e.g., CpG) into cells for efficient recognition of endosomal Toll‐like receptor 9 and subsequent enhanced immunostimulatory activity in vitro and in vivo. No apparent toxicity is observed with systemic delivery of the DNA–NMOFs in vivo. Overall, these results suggest that the strategy allows for surface functionalization of MOFs with different functional DNAs, extending the use of these materials to diverse applications in biosensor, bioimaging, and nanomedicine. 相似文献
99.
本文采用两步合成工艺,通过化学共沉淀工艺制备β-Bi_2O_3纳米颗粒;经室温原位还原硝酸银,制备不同包覆量纳米Ag负载的Bi_2O_3(Ag/β-Bi_2O_3)光催化剂颗粒。对该光催化剂进行结构表征,并以甲基橙溶液模拟废水在可见光下评价其光催化性能。透射电子显微镜(TEM)测试表明纳米Ag均匀包覆于β-Bi_2O_3颗粒表面,其中β-Bi_2O_3聚集体的颗粒尺寸约30nm,而分散的纳米Ag晶体约为20nm。紫外可见光谱(UV-vis)谱图表明Ag/β-Bi_2O_3复合材料的带隙能比纯相Bi_2O_3要小,对可见光利用率相应增加,光催化性能随之增强。其中以2.0%(质量比)Ag包覆β-Bi_2O_3颗粒的光催化性能最佳。 相似文献
100.
The luminescence of semiconductor quantum dots (QDs) can be adjusted using the piezotronic effect. An external mechanical force applied on the QD generates a piezoelectric potential, which alters the luminescence of the QD. A small mechanical force may induce a significant change on the emission spectrum. In the case of InN QDs, it is demonstrated that the unforced emission wavelength is more than doubled by a force of 1 μN. The strategy of using the piezotronic effect to tune the color of the emission leads to promising noncontact forcemeasurement applications in biological and medical sensors and force-sensitive displays. Several piezoelectric semiconductor materials have been investigated in terms of the tunability of the emission wavelength in the presence of an external applied force. It is found that CdS and CdSe demonstrate much higher tunability δλ/δF, which makes them suitable for micro/nano-newton force measurement applications. 相似文献