This paper proposes a peak-to-valley time-based electricity price optimization method based on NSGA-II with distributed power supply. First, the curve-fitting method is used to obtain the comprehensive electricity pri...
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With the rapid development of CPS technology, the identification and detection of malware has become a matter of concern in the industrial application of CPS. Currently, advanced machine learning methods such as deep ...
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As an important task of video enhancement,a lot of video stabilization methods have been *** in many real-world applications,especially the systems with human-computer interactions,existing methods only remove camera ...
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ISBN:
(纸本)9781509046584
As an important task of video enhancement,a lot of video stabilization methods have been *** in many real-world applications,especially the systems with human-computer interactions,existing methods only remove camera motion in stabilized frames,the remaining object motion will also lead to deviations in manual *** this paper,we collect practical hand drawn bounding boxes which have been shown to contain serious *** we propose a target-focused video stabilization method consisting of a proposal-based detection component and a trackingbased motion estimation *** experiments demonstrate our method can remove camera jitter and target motion simultaneously,and also offer users a friendly and effective way to draw accurate target regions.
The phase delay problem of invisibility cloaks designed by optical conformal mapping is referred to the optical path difference between the waves in upper and lower Riemann sheets. As the frequency changes, the phase ...
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The phase delay problem of invisibility cloaks designed by optical conformal mapping is referred to the optical path difference between the waves in upper and lower Riemann sheets. As the frequency changes, the phase delay varies accordingly (here, we call it geometrical dispersion), which restricts the cloaks to working only at some discrete frequencies. Here, we solve the phase-delay problem by placing an optically null medium in the lower Riemann sheet. The conformal cloaks designed by using our method have many advantages, such as a continuous working band (no geometrical dispersion), omnidirectionality, robustness under frequency shifts, and no need for any complex materials that are both anisotropic and inhomogeneous. We also design metallic microchannels to realize our cloaks.
In order to cope with the incompatibility of traditional AGC control under CPS control performance standard, this paper proposes a hierarchical control framework based on DQN algorithm. It effectively solves the probl...
In order to cope with the incompatibility of traditional AGC control under CPS control performance standard, this paper proposes a hierarchical control framework based on DQN algorithm. It effectively solves the problem of dimensionality disaster of Q learning by using neural network instead of state action pair, and speed up the convergence. Through simulation verification, this method can effectively improve the system CPS control performance index and effectively reduce the system power generation cost.
With the high proportion of renewable energy access to the distribution network, the volatility and randomness of renewable energy output will have a serious impact on the distribution network, especially at the peak ...
With the high proportion of renewable energy access to the distribution network, the volatility and randomness of renewable energy output will have a serious impact on the distribution network, especially at the peak of renewable power output, the reverse trend phenomenon is obvious. The active distribution network displays the 'power' characteristics externally, which makes the voltage problem and transmission congestion problem in the distribution network very serious. This paper establishes a distributed energy storage optimization configuration model that takes into account the voltage quality, and considers the energy storage operation strategy optimization in the energy storage site selection and volume model, which makes the energy storage configuration more reasonable, improves the voltage quality and enhances the renewable energy consumption capacity, improve the economics of system operation.
Delamination and microcracks as well as spatters are known to be inherently associated with laser drilling thermal barrier coated materials. In this study, response surface method (RSM) and single-variable method were...
Delamination and microcracks as well as spatters are known to be inherently associated with laser drilling thermal barrier coated materials. In this study, response surface method (RSM) and single-variable method were employed to correlate the laser parameters including pulse length, peak power, pulse rate, and pulse numbers as well as the interactions among them with such defects in laser percussion drilling. Detailed observation and analysis reveals that narrow pulse length, lower peak power, and low pulse rate can produce smaller cracks area on the side wall, among which the effect of pulse length is more outstanding. As for spatters around hole entrance, the interactions among these factors were identified and a combination of higher peak power, proper pulse length (in this model not exceed 1 ms), higher pulse rate, and small number of pulses are conducive to minimize the spatter volume. Furthermore, the thermal effect near the thermal barrier coating/bond coat (TBC/BC) is especially prominent in laser drilling with wide pulse length and low peak power. The removal mechanism occurred near TBC/BC also determines the delamination crack size. And higher peak power with narrow pulse length should be a good strategy in order to break through the TBC as soon as possible and shelter the TBC or TBC/BC from thermal damage.
The effect of laser shock peening (LSP) on the residual stress, microstructure and hot corrosion behavior of damage-tolerant TC21 alloy was investigated. The equilateral scanning pattern was adopted to obtain a large ...
The effect of laser shock peening (LSP) on the residual stress, microstructure and hot corrosion behavior of damage-tolerant TC21 alloy was investigated. The equilateral scanning pattern was adopted to obtain a large overlapping area for LSP. The hot corrosion experiments in a salt mixture composed of 75 wt.% Na2SO4 + 25 wt.% NaCl at 700 and 800 °C for a total exposure of 25 h were conducted. The results demonstrated that LSP caused a high compressive residual stress with a significant increase in micro-hardness and microstructural changes in the form of crystal defects, i.e., high density dislocations. The crystal defects promoted the outward diffusion of Al, Cr and Ti to form protective mixed oxides (Al, Cr, Ti)O2. These oxides improved the adhesion of outer oxide layer and hindered the inward diffusion of O, S and Cl, which was beneficial to improve hot corrosion resistance. The mass gains of LSP-treated specimens after hot corrosion at 700 and 800 °C were, respectively, 3.72 and 4.78 mg/cm2, which were much lower than those of untreated specimens (5.65 and 6.81 mg/cm2). Therefore, LSP leads to an improvement in resistance to hot corrosion of TC21 alloy.
The combination effect of cation vacancies and O2 adsorption on ferromagnetism of Na0.5Bi0.5TiO3(100) surface is studied by using density functional theory. An ideal Na0.5Bi0.5TiO3(100) surface is non-magnetic and...
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The combination effect of cation vacancies and O2 adsorption on ferromagnetism of Na0.5Bi0.5TiO3(100) surface is studied by using density functional theory. An ideal Na0.5Bi0.5TiO3(100) surface is non-magnetic and the cation vacancy could induce the magnetism. By comparing the formation energies for Na, Bi and Ti vacancy, the Na vacancy is more stable than the others. Therefore, we focus on the configuration and electric structure for the system of O2 molecule adsorption on the Na0.5Bi0.5TiO3(100) surface with a Na vacancy. Among the five physisorption configurations we considered, the most likely adsorption position is Na vacancy. The O2 adsorption enhances the magnetism of the system. The contribution of spin polarization is mainly from the O 2p orbitals. The characteristics of exchange coupling are also calculated, which show that the ferromagnetic coupling is favorable. Compared with the previous calculation results, our calculations could explain the room-temperature ferromagnetism of Na0.5Bi0.5TiO3 nanocrytalline powders more reasonably, because of taking into account adsorbed oxygen and cation vacancies. Moreover, our results also show that adsorption of O2 molecule as well as introduction of cation vacancies may be a promising approach to improve multiferroic materials.
Development of 3D hierarchically porous graphene (HPG) with supercapacitor performances at low cost has remained a challenge in electrochemical devices. Recently, laser engraving technology has been proposed as a prom...
Development of 3D hierarchically porous graphene (HPG) with supercapacitor performances at low cost has remained a challenge in electrochemical devices. Recently, laser engraving technology has been proposed as a promising and very useful method to inscribe self-designed electrode array directly onto polymeric substrates by instantaneously converting the starting material into few-layer graphene. Here we show HPG fabrication on commercial bakelite resulting in porous graphene embedded in polymer surface using the high repetition nanosecond fiber laser engraving under nitrogen atmosphere. The results showed that the as-prepared HPG presents a combination of interconnected macro-, meso- and micropores with a multi-modal pore size distribution. The morphologies, microstructures and their properties of HPG films can be governed by the laser processing parameters. Moreover, the HPG-based supercapacitors show outstanding electrochemical performance with specific capacitance superior to other supercapacitors reported previously. The simple, rapid and low-cost approach proposed in this work has great potential in large-scale applications of electronic and energy storage devices.
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