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141.
Min‐Seok Kim Xing‐Hua Ma Ki‐Hyun Cho Seung‐Yeol Jeon Kahyun Hur Yun‐Mo Sung 《Advanced materials (Deerfield Beach, Fla.)》2018,30(6)
Despite tellurium being less abundant in the Earth's crust than gold, platinum, or rare‐earth elements, the number of industrial applications of tellurium has rapidly increased in recent years. However, to date, many properties of tellurium and its associated compounds remain unknown. For example, formation mechanisms of many tellurium nanostructures synthesized so far have not yet been verified, and it is unclear why tellurium can readily transform to other compounds like silver telluride by simply mixing with solutions containing silver ions. This uncertainty appears to be due to previous misunderstandings about the tellurium structure. Here, a new approach to the tellurium structure via synthesized structures is proposed. It is found that the proposed approach applies not only to these structures but to all other tellurium nanostructures. Moreover, some unique tellurium nanostructures whose formation mechanism are, until now, unconfirmed can be explained. 相似文献
142.
Wireless sensor and actuator networks combine a large number of sensors and a lower number of actuators that are connected with wireless medium, providing distributed sensing and executing appropriate tasks in a special region of interest. To accomplish effective sensing and acting tasks, efficient coordination mechanism among the nodes is required. As an attempt in this direction, this paper develops a collaborative control and estimation mechanism, which addresses the nodes coordination in a distributed manner. First, we propose a regional controllability‐based virtual force algorithm as an actuator deployment strategy to enhance area coverage after an initial random placement of actuators. During this process, a dynamic coordination mechanism is adopted to control nodes. This mechanism incorporates two components, namely, proportional‐integral‐derivative neural network and recursive least squares‐based Kalman filter algorithms. Taking advantage of feedback control and online learning technology, the proposed coordination mechanism schedules the corresponding nodes on the basis of the characteristics of current events, utilizes proportional‐integral‐derivative neural network controller inside each actuator to improve system transient and steady‐state responses, and deals with system state/parameter estimation problems according to the recursive least squares‐based Kalman filter algorithm, so as to achieve better control accuracy. Simulations demonstrate the effectiveness of our proposed methods. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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In this article, the room-temperature solution fluorescence quenching of electron-deficient anthracenes such as 9-cyanoanthracene (CNA), 9,10-dicyanoanthracene (DCNA), and 9,10-dichloroanthracene (DCLA) by polysilane copolymers was studied. The fluorescence quenching data was in conformity with the Stern-Volmer equation F0/F = 1 + Ksv[Q], the F0/F−[Q] straight lines were drawn, and the fluorescence quenching constants Ksv were obtained. By measuring the fluorescence lifetimes of the anthracenes, the fluorescence quenching rate constants kq were calculated. Based on experiments and references, we tentatively proposed that for the same polysilane copolymer quencher the fluorescence quenching was caused mainly by the polysilane Si—Si chain and affected in a small degree by the side substituents attached to the Si—Si chain. In addition, it was observed that the order of the fluorescence quenching rate constants kq of the above three electron-deficient anthracenes by the same polysilane copolymer was DCNA > CNA > DCLA, which is just in keeping with that of their electron deficiency. © 1996 John Wiley & Sons, Inc. 相似文献
145.
冲击响应谱在惯导减振防冲设计中的应用 总被引:3,自引:0,他引:3
根据冲击原理,研究惯导减振系统在半正弦冲击激励下的响应特性,绘制了惯导系统在半正弦冲击激励下的冲击响应谱图。根据冲击响应谱图,可为惯导系统防冲设计提供正确、有效的理论依据,同时,为使减振器同时具备减振、防冲两种性能,冲击响应谱对于减振器关键参数选择、减振系统优化也具有重要应用价值。最后文章依据该研究结论,对某惯导系统进行了实际设计计算。 相似文献
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