A strategy was proposed to predict accurately the dielectric permittivity and dielectric strength based on the Onsager local field *** molecular dynamic simulation was utilised to analyse the dipole moment fluctuation...
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A strategy was proposed to predict accurately the dielectric permittivity and dielectric strength based on the Onsager local field *** molecular dynamic simulation was utilised to analyse the dipole moment fluctuation in polyimide(PI)to reflect the polar-isation response of applied electric *** simulation results revealed that the optical dielectric permittivity and static dielectric permittivity were 2.62 and 3.34,showing that the electronic displacement polarisation of the PI acted as a major *** deviation between simulated and measured values of the frequency-dependent relative dielectric permittivity was no more than 5%,which exhibited high *** the polarisation response of the polar groups in the PI was at infrared frequencies,the conductive loss may be the dominant role in 102–106 Hz at room ***,the effect of Joule heat on the structure,dielectric permittivity and Young modulus was considered to accurately predict the dielectric strength of the PI(359 kV/mm),which was in agreement with experimental values in the *** results establish a clear correlation between structural characteristics and dielectric properties of the PI,which would be the theoretical insights into the design and synthesis of the PI with tailored dielectric properties.
Recently, neural network-based in-loop filters have been rapidly developed, effectively improving the reconstruction quality and compression efficiency in video coding. Existing deep in-loop filters typically employed...
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Focusing on the non-concave trajectory constraint,a sliding-mode-based nonsingular feedback fast fixed-time three-dimensional terminal guidance of rotor unmanned aerial vehicle landing,planetary landing and spacecraft...
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Focusing on the non-concave trajectory constraint,a sliding-mode-based nonsingular feedback fast fixed-time three-dimensional terminal guidance of rotor unmanned aerial vehicle landing,planetary landing and spacecraft rendezvous and docking terminal phase with external disturbance is investigated in this ***,a fixed-time observer based on real-time differentiator is developed to compensate for the external disturbance,whose estimation error can converge to zero after a time independent of the initial ***,a sliding surface ensuring fixed-time convergence is *** sliding surface can guarantee that the vehicle achieves a non-concave trajectory,which is better for avoiding collision and maintaining the visibility of the landing site or docking ***,the nonsingular guidance ensuring the fixed-time convergence of the sliding surface is proposed,which is continuous and chatter *** last,three numerical simulations of Mars landing are performed to validate the effectiveness and correctness of the designed scheme.
Industrial cyber-physical systems closely integrate physical processes with cyberspace, enabling real-time exchange of various information about system dynamics, sensor outputs, and control decisions. The connection b...
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Industrial cyber-physical systems closely integrate physical processes with cyberspace, enabling real-time exchange of various information about system dynamics, sensor outputs, and control decisions. The connection between cyberspace and physical processes results in the exposure of industrial production information to unprecedented security risks. It is imperative to develop suitable strategies to ensure cyber security while meeting basic performance *** the perspective of control engineering, this review presents the most up-to-date results for privacy-preserving filtering,control, and optimization in industrial cyber-physical systems. Fashionable privacy-preserving strategies and mainstream evaluation metrics are first presented in a systematic manner for performance evaluation and engineering *** discussion discloses the impact of typical filtering algorithms on filtering performance, specifically for privacy-preserving Kalman filtering. Then, the latest development of industrial control is systematically investigated from consensus control of multi-agent systems, platoon control of autonomous vehicles as well as hierarchical control of power systems. The focus thereafter is on the latest privacy-preserving optimization algorithms in the framework of consensus and their applications in distributed economic dispatch issues and energy management of networked power systems. In the end, several topics for potential future research are highlighted.
The directional annealing technique is widely used to prepare columnar grains or single *** investigate the effect of hot zone temperature and temperature gradient on the growth of columnar crystals,Ti43Al alloys were...
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The directional annealing technique is widely used to prepare columnar grains or single *** investigate the effect of hot zone temperature and temperature gradient on the growth of columnar crystals,Ti43Al alloys were heat treated by the directional annealing technique and their mechanical properties were *** results show that columnar grains with a maximum size of 22.29 mm can be obtained at a hot zone temperature of 1,350℃ and a temperature gradient of 8 K·mm^(-1).During the directional annealing process,Ti43Al alloys are heated toαsingle-phase domain to start the phase *** grains with a microstructure of fully lamellar colonies are obtained at different hot zone temperatures and temperature *** distribution of the orientation difference for theα2 phase was found to be more random,suggesting that the growth of the columnar crystals may be stochastic in *** testing results show that the strength and elongation of directional annealed Ti43Al alloy at 1,400℃-8 K·mm^(-1) are 411.23 MPa and 2.29%,and the remaining directional annealed alloys show almost plasticity.
In a crowd density estimation dataset,the annotation of crowd locations is an extremely laborious task,and they are not taken into the evaluation *** this paper,we aim to reduce the annotation cost of crowd datasets,a...
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In a crowd density estimation dataset,the annotation of crowd locations is an extremely laborious task,and they are not taken into the evaluation *** this paper,we aim to reduce the annotation cost of crowd datasets,and propose a crowd density estimation method based on weakly-supervised learning,in the absence of crowd position supervision information,which directly reduces the number of crowds by using the number of pedestrians in the image as the supervised *** this purpose,we design a new training method,which exploits the correlation between global and local image features by incremental learning to train the ***,we design a parent-child network(PC-Net)focusing on the global and local image respectively,and propose a linear feature calibration structure to train the PC-Net simultaneously,and the child network learns feature transfer factors and feature bias weights,and uses the transfer factors and bias weights to linearly feature calibrate the features extracted from the Parent network,to improve the convergence of the network by using local features hidden in the crowd *** addition,we use the pyramid vision transformer as the backbone of the PC-Net to extract crowd features at different levels,and design a global-local feature loss function(L2).We combine it with a crowd counting loss(LC)to enhance the sensitivity of the network to crowd features during the training process,which effectively improves the accuracy of crowd density *** experimental results show that the PC-Net significantly reduces the gap between fullysupervised and weakly-supervised crowd density estimation,and outperforms the comparison methods on five datasets of Shanghai Tech Part A,ShanghaiTech Part B,UCF_CC_50,UCF_QNRF and JHU-CROWD++.
In a crowd-sensing system, effective transmission of sensing data is an important step in improving task distribution efficiency. In real-life scenarios, when resources are limited or geographic conditions are harsh, ...
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In the scenario of a steam generator tube rupture accident in a lead-cooled fast reactor,secondary circuit subcooled water under high pressure is injected into an ordinary-pressure primary vessel,where a molten lead-b...
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In the scenario of a steam generator tube rupture accident in a lead-cooled fast reactor,secondary circuit subcooled water under high pressure is injected into an ordinary-pressure primary vessel,where a molten lead-based alloy(typically pure lead or lead-bismuth eutectic(LBE))is used as the *** clarify the pressure build-up characteristics under water-jet injection,this study conducted several experiments by injecting pressurized water into a molten LBE pool at Sun Yat-sen *** obtain a further understanding,several new experimental parameters were adopted,including the melt temperature,water subcooling,injection pressure,injection duration,and nozzle *** detailed analyses,it was found that the pressure and temperature during the water-melt interaction exhibited a consistent variation trend with our previous water-droplet injection mode LBE ***,the existence of a steam explosion was confirmed,which typically results in a much stronger pressure *** the non-explosion cases,increasing the injection pressure,melt-pool temperature,nozzle diameter,and water subcooling promoted pressure build-up in the melt ***,a limited enhancement effect was observed when increasing the injection duration,which may be owing to the continually rising pressure in the interaction vessel or the isolation effect of the generated steam *** of whether a steam explosion occurred,the calculated mechanical and kinetic energy conversion efficiencies of the melt were relatively small(not exceeding 4.1%and 0.7%,respectively).Moreover,the range of the conversion efficiency was similar to that of previous water-droplet experiments,although the upper limit of the jet mode was slightly lower.
Lithium-ion batteries with polymer electrolytes(PEs)are promising candidates for high safety performance ***,conventional PEs suffer from poor compatibility and high impedance of electrolyte-electrode ***,we present a...
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Lithium-ion batteries with polymer electrolytes(PEs)are promising candidates for high safety performance ***,conventional PEs suffer from poor compatibility and high impedance of electrolyte-electrode ***,we present a method of the interfacial modification for PEs to inhibit lithium dendrites based on the solution to the interfacial *** strategy is to improve the interfacial properties and inhibit the dendrite generation by coating a modified layer on PEs of the anode side with acetylene black(AB)and *** mixed conductive layer(MCL)can promote the generation of Li3N and LiF with a uniform arrangement of electrons to form a dense solid electrolyte interphase layer and the even lithium-ion deposition for improving the performance and stability of the battery during *** adding the MCL,the discharge capacity of solid lithium-ion batteries(SLIBs)with lithium bis(trifluoromethanesulfonyl)imide(LiTFSI)/organic modified montmorillonite(OMMT)/soybean isolate protein(SPI)/poly(vinylidene fluoride)(PVDF)(LOSP)PE from 74.2 mAh g^(-1)up to 111.1 mAh g^(-1)(AB-LiTFSI/OMMT/SPI/PVDF(AB-LOSP))and 111.6 mAh g^(-1)(AB/MXene-LiTFSI/OMMT/SPI/PVDF(AB/MXene-LOSP)).The polarization voltage dropped by 0.06 and 0.12 V,*** work represents a milestone in the dendrite-free SLIBs with good performances.
The authors investigate the effects of nanofillers with varying band‐gap energies on the space charge properties,breakdown field strength,and bulk resistivity of epoxy(EP)‐based ***,the molecular orbital distributio...
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The authors investigate the effects of nanofillers with varying band‐gap energies on the space charge properties,breakdown field strength,and bulk resistivity of epoxy(EP)‐based ***,the molecular orbital distribution of both the epoxy resin and nanofillers were examined through density functional *** results indicate that the space charge accumulation within silicon dioxide/EP and germanium oxide/EP is reduced,leading to a more uniformly distributed electric field intensity within the specimen when compared to *** a result,both materials exhibit improved AC breakdown field strength and volume ***,the amount of charge accumulated within tin dioxide/EP is higher,resulting in lower breakdown field strength than *** lowest unoccupied molecular orbital and the highest occupied molecular orbital energy level differences between epoxy and nanofillers introduce electron traps and hole traps at the interface,forming interfacial traps that affect the space charge distribution within the specimen,as well as the trap energy levels within the *** the experimental results,shallow traps promote space charge accumulation and reduce the breakdown field strength,while deep traps have the opposite effect.
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