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ABSTRACTThe problem of mixed discrete-continuous task planning for mechanical systems, such as aerial drones or other autonomous units, can be often treated as a sequence of point-to-point trajectories. In this work, the problem of optimal trajectory planning under a combined completion time and energy criterion, for a straight point to point path for a second-order system with quadratic under state (velocity) and control (acceleration) constraints is considered. The solution is obtained and proved to be optimal using the Pontryagin Maximum Principle. Simulation results for different cases are presented and compared with a customary numerical optimal control solver. 相似文献
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Asmaa Kadim Ayal Zulkarnain Zainal Hong-Ngee Lim Zainal Abidin Talib Ying-Chin Lim Sook-Keng Chang Araa Mebdir Holi 《Optical and Quantum Electronics》2017,49(4):164
The self-organized titania nanotube arrays (NTAs) fabricated by anodisation has gained enormous interest due to its high spatial orientation, excellent charge transfer structure, and large internal surface area; all are crucial properties influencing the absorption and propagation of light. In this study, a composite material, CdSe nanoparticle/TiO2 nanotube arrays (CdSe/TiO2 NTAs) were assembled through the insertion of CdSe nanoparticles onto the anodized TiO2 nanotube arrays via electrochemical deposition. The annealing temperature of CdSe/TiO2 NTAs was varied from 200 to 350 °C and was found to play an important role in controlling the formation of CdSe nanoparticles on TiO2 NTAs. Characterizations of the films were performed by using field emission scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, high resolution transmission electron microscopes, X-ray diffractometry and UV–visible diffuse reflectance spectroscopy. The transient photocurrent was examined in a three-electrode system under halogen illumination by using the prepared film as the photoanode. It was found that the CdSe nanoparticles were susceptible to spread through electrochemical deposition and formed on the nanotubes by annealing in nitrogen atmosphere. The increment in annealing temperature has resulted in greater amount of CdSe loaded onto TiO2 nanotube arrays. Therefore, a suitable annealing temperature can enhance the particle interaction, leading to considerable improvement in PEC performance. The sensitized CdSe/TiO2 NTAs annealed at 250 °C displayed 84 folds improvement in photoconversion efficiency than that of bare TiO2 NTAs counterparts. 相似文献
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Taitler Ayal Ioslovich Ilya Karpas Erez Gutman Per-Olof 《Journal of Optimization Theory and Applications》2022,192(2):725-757
Journal of Optimization Theory and Applications - The problem of a planar vehicle moving on a surface, such as aerial drones or small naval vessels, can be treated as a series of trajectory... 相似文献
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Asmaa Kadim Ayal Ying-Chin Lim Ahlam Mohammed Farhan 《Research on Chemical Intermediates》2018,44(12):7231-7240
A photoconversion efficiency of 2.12% was obtained under visible light illumination by nanostructure-sensitized photoelectrochemical cells using Mn/CdS as sensitizer loaded on TiO2 nanotube arrays (NTAs) (Mn/CdS/TiO2). Sensitization of Mn on CdS nanoparticles pre-loaded on TiO2 NTAs was carried out by a two-step electrodeposition method. Compared with unsensitized TiO2 NTAs, the photocurrent had increased from 0.03 to 4.12 for Mn/CdS/TiO2 prepared at 1 min. The effects of deposited Mn on the physical, chemical, and photoelectrochemical properties of the CdS/TiO2 NTAs nanostructure were investigated by using UV–visible diffuse reflectance spectroscopy, X-ray diffractometry, and field-emission scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. The photoelectrochemical analysis was examined in a three-electrode system under a halogen illumination by using the prepared film as the photo-anode. 相似文献
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Atnafu Guadie Assefa Ayal Adugna Mesfin Mulugeta Legesse Akele Addis Kokeb Alemu Bhagavanth Reddy Gangapuram Veerabhadram Guttena Madhusudhan Alle 《Journal of Cluster Science》2017,28(3):917-935
In this work we report straightforward, an economically viable, one-step microwave-assisted green synthesis of well stabilized gold nanoparticles (AuNPs) by reducing chloroauric acid with natural water soluble olibanum gum (Boswellia serrate). The olibanum gum acts as a dual role of reducing and capping agent for synthesis of AuNPs. The formation of AuNPs was confirmed using UV–Vis spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy and electron diffraction. The results indicated that the synthesized NPs were well dispersed and spherical in shape had an average diameter of 3 ± 2 nm. The reaction parameters significantly affected the formation of NPs, as the concentration of gum and irradiation time increases the formation of NPs particles increases and size of particles are reduced. In addition, it has been shown that these olibanum gum capped AuNPs functioned as effective homogeneous catalyst for the reduction of two model reactions hexacyanoferrate(III) and 4-nitrophenol by sodium borohydride. The kinetic investigations were carried out at different amount of AuNPs and different temperatures. 相似文献
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A proper coloring of the edges of a graph G is called acyclic if there is no 2‐colored cycle in G. The acyclic edge chromatic number of G, denoted by a′(G), is the least number of colors in an acyclic edge coloring of G. For certain graphs G, a′(G) ≥ Δ(G) + 2 where Δ(G) is the maximum degree in G. It is known that a′(G) ≤ 16 Δ(G) for any graph G. We prove that there exists a constant c such that a′(G) ≤ Δ(G) + 2 for any graph G whose girth is at least cΔ(G) log Δ(G), and conjecture that this upper bound for a′(G) holds for all graphs G. We also show that a′(G) ≤ Δ + 2 for almost all Δ‐regular graphs. © 2001 John Wiley & Sons, Inc. J Graph Theory 37: 157–167, 2001 相似文献
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Franco M. Rabagliati Mnica A. Prez Rodrigo A. Cancino Marcelo A. Soto Francisco J. Rodríguez Carlos J. Caro Arturo G. Len Hugo A. Ayal Raúl Quijada 《Macromolecular Symposia》2001,168(1):31-42
Combined systems including diphenylzinc, Ph2Zn, a metallocene, and methylaluminoxane, MAO, have been employed to initiate styrene polymerization. These initiator systems have been also used to initiate the copolymerization of styrene with p‐alkylsubstituted styrenes and with α‐olefins. Both polymerization and copolymerization processes depend on the nature of the metallocene included in the initiator system, the presence of Ph2Zn, the temperature and the solvent used. Titanocenes produced syndiotactic polystyrene, s‐PS, while zirconocenes gave atactic polystyrene, a‐PS, with a certain content, less the 20% of s‐PS. For copolymerizations the conversion to polymer was also influenced by the comonomer nature and its molar proportion in the initial feed, as well as the sort of metallocene, titanocene or zirconocene included. 相似文献
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