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Recent Progress of Bionic Hierarchical Structure in the Field of Thermal Insulation Protection

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Journal of Bionic engineering 2024年第1期21卷 1-18页

作者： Yina Zhuge Fujuan Liu National engineering Laboratory for Modern Silk College of Textile and Clothing EngineeringSoochow UniversitySuzhou 215123China

Some living organisms with hierarchical structures in nature have received extensive attention in various *** hierarchical structure with multiple pores,a large number of solid-gas interfaces and tortuous conduction paths provide a new direction for the development of thermal insulation materials,making the living creatures under these extreme conditions become the bionic objects of scientific *** this review,the research progress of bionic hierarchical structure in the field of heat insulation is *** bears,cocoons,penguin feathers and wool are typical examples of heat preservation hierarchy in nature to introduce their morphological *** the same time,the thermal insulation mechanism,fractal model and several preparation methods of bionic hierarchical structures are emphatically *** application of hierarchical structures in various fields,especially in thermal insulation and infrared thermal stealth,is ***,the hierarchical structure is prospected.

关键词： Hierarchical structure Bionic Heat insulation Fractal model Cocoons

Spherical Bi_(2)O_(3)/ATO catalyst with N_(2)pre-reduction electrocatalytic reduction of CO_(2)to formic acid

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Journal of Environmental Sciences 2024年第6期140卷 331-340页

作者： Junying Yi Yuli Chen Dongze Lai Bihong Lv Xiaomin Wu Guohua Jing Department of Environmental Science&engineering College of Chemical EngineeringHuaqiao UniversityXiamenFujian 361021China

To achieve carbon neutrality,the Chinese government needs to gain a comprehensive understanding of the sources and drivers of greenhouse gas(GHG)emissions,particularly at the county *** County in eastern China is a typical example of an industrial transformation from quarrying to a low-carbon *** study analyzed the decoupling types and structural characteristics of GHG emissions and the driving factors of carbon dioxide(CO_(2))emissions in the Anji from 2006 to 2019,and explored the differences between countylevel and provincial-level or city-level *** was observed that energy-related activities are the main source of GHG emissions in Anji and that economic development is the driving factor behind the increasing CO_(2)***,industrial transformation and upgradation coupled with the alternative use of clean energy limit the growth of GHG *** study details the GHG emissions of county during the industrial transformation stage and provides corresponding policy recommendations for county governments.

关键词： N_(2)prereduction CO_(2)electroreduction Bi_(2)O_(3)/ATO catalyst Formate

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Stability Analysis of DC Microgrid Clusters Based on Step-by-step System Matrix Building Algorithm

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 900-912页

作者： K.Jithin N.Mayadevi R.Hari Kumar V.P.Mini the Department of Electrical engineering College of Engineering TrivandrumAPJ Abdul Kalam Technological University(APJAKTU)ThiruvananthapuramIndia

DC microgrids(DCMGs)are made up of a network of sources and loads that are connected by a number of power electronic converters(PECs).The increase in the number of these PECs instigates major concerns in system *** interconnecting the microgrids to form a cluster,the system stability must be *** paper proposes a novel stepby-step system matrix building(SMB)algorithm to update the system matrix of an existing DCMG cluster when a new microgrid is added to the cluster through a distribution *** stability of the individual DCMGs and the DCMG cluster is analyzed using the eigenvalue ***,the particle swarm optimization(PSO)algorithm is used to retune the controller gains if the newly formed cluster is not *** simulation of the DCMG cluster is carried out in MATLAB/Simulink environment to test the proposed *** results are also validated using the OP4510 real-time simulator(RTS).

关键词： Converter DC microgrid cluster eigenvalue interconnection particle swarm optimization system stability system matrix

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A Weakly-Supervised Crowd Density Estimation Method Based on Two-Stage Linear Feature Calibration

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 965-981页

作者： Yong-Chao Li Rui-Sheng Jia Ying-Xiang Hu Hong-Mei Sun the college of Computer Science and engineering Shandong University of Science and TechnologyQingdao 266590 the Faculty of Information Science and engineering Ocean University of ChinaQingdao 266000China the college of Computer Science and engineering Shandong University of Science and TechnologyQingdao 266590China the college of Computer Science and engineering Nanjing University of Science and TechnologyNanjing 210000China

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++.

关键词： Crowd density estimation linear feature calibration vision transformer weakly-supervision learning

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Enhancing the Goos-Hänchen shift based on quasi-bound states in the continuum through material asymmetric dielectric compound gratings

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Chinese Physics B 2024年第3期33卷 393-400页

作者：江孝伟方彬占春连 college of Optical and Electronic Technology China Jiliang UniversityHangzhou 310018China college of Information engineering Quzhou College of TechnologyQuzhou 324000China

Quasi-bound state in the continuum(QBIC)resonance is gradually attracting attention and being applied in Goos-Hänchen(GH)shift enhancement due to its high quality(Q)factor and superior optical ***,symmetry-protected QBIC resonance is often achieved by breaking the geometric symmetry,but few cases are achieved by breaking the material *** paper proposes a dielectric compound grating to achieve a high Q factor and high-reflection symmetry-protectede QBIC resonance based on material *** calculations show that the symmetry-protected QBIC resonance achieved by material asymmetry can significantly increase the GH shift up to-980 times the resonance wavelength,and the maximum GH shift is located at the reflection peak with unity *** paper provides a theoretical basis for designing and fabricating high-performance GH shift tunable metasurfaces/dielectric gratings in the future.

关键词： bound state in the continuum Goos-Hänchen shift dielectric compound grating material asymmetry

Optimized Selection Method of Air Combat Course of Action under Stochastic Uncertainty

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Journal of Systems Science and Systems engineering 2024年第4期33卷 494-518页

作者： Yun Zhong Jieyong Zhang Peng Sun Lujun Wan Kepeng Wang Information and Navigation college Air Force Engineering UniversityXi’an710077China Equipment Management and Unmanned Aerial Vehicle engineering college Air Force Engineering UniversityXi’an710051China Air Traffic Control and Navigation college Air Force Engineering UniversityXi’an710051China Unit 94040 of PLA Korla841000China

Aiming at the design problem of aviation swarm combat course of action(COA),considering the influence of stochastic parameters in the causal relationship model and optimization problem model,according to the dynamic influence net(DIN)theory,stochastic simulation technique,feedforward neural network(FNN)function approximation technique and multi-objective artificial fish school algorithm(MOAFSA),this paper proposed a COA optimized method based on DIN and multi-objective stochastic chance constraint optimization for aviation swarm ***,on the basis of establishing the overall framework of the model and defining the elements of causal relationship modeling,the static and dynamic causal relationship modeling and optimization problem modeling were carried out ***,the probability propagation mechanism of DIN was established,which mainly included two aspects,i.e.,the overall process and the specific ***,input and output data were generated based on stochastic *** to these data,FNN was adopted for function approximation,and MOAFSA was adopted for iterative ***,the rationality of the model,and the effectiveness and superiority of the algorithm were verified through multiple sets of simulation cases.

关键词： Stochastic uncertainty aviation swarm stochastic simulation course of action feedforward neural network multi-objective artificial fish school algorithm

An economic way to achieve all-weather CO2 reduction

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National Science Review 2024年第3期11卷 46-47页

作者： Junwang Tang Department of Chemical engineering University College London

Utilising solar power to convert carbon dioxide（CO2） into hydrocarbon fuels presents an eco-friendly method to address dependence on fossil fuels and contribute to a net-zero CO2emission goal[1,2].

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Stacking MoS_(2) flower-like microspheres on pomelo peels-derived porous carbon nanosheets for high-efficient X-band electromagnetic wave absorption

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Nano Research 2024年第3期17卷 1607-1615页

作者： Jia Zhao Zhe Gu Qingguo Zhang college of Chemistry and Materials engineering Bohai UniversityJinzhou 121013China

The key to solve increasingly severe electromagnetic(EM)pollution is to explore sustainable,easily prepared,and cost-effective EM wave absorption materials with exceptional absorption ***,instead of anchoring on carbon materials in single layer,MoS_(2) flower-like microspheres were stacked on the surface of pomelo peels-derived porous carbon nanosheets(C)to fabricate MoS_(2)@C nanocomposites by a facile solvothermal *** wave absorption performances of MoS_(2)@C nanocomposites in X-band were systematically investigated,indicating the minimum reflection loss(RLmin)of-62.3 dB(thickness of 2.88 mm)and effective absorption bandwidth(EAB)almost covering the whole X-band(thickness of 2.63 mm)with the filler loading of only 20 wt.%.Superior EM wave absorption performances of MoS_(2)@C nanocomposites could be attributed to the excellent impedance matching characteristic and dielectric loss capacity(conduction loss and polarization loss).This study revealed that the as-prepared MoS_(2)@C nanocomposites would be a novel prospective candidate for the sustainable EM absorbents with superior EM wave absorption performances.

关键词： pomelo peels-derived porous carbon nanosheets(C) MoS_(2)@C nanocomposites stacked structure electromagnetic(EM)wave absorption

Churning loss characteristics of a wet three-phase high-speed reluctance motor

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Journal of Zhejiang University-Science A(Applied Physics & engineering) 2024年第3期25卷 251-267页

作者： Zhenzhou ZHANG Mingzhu DAI Chenchen ZHANG Yi CHEN Bin MENG college of Mechanical engineering Zhejiang University of TechnologyHangzhou 310023China

With the increasing requirements of electro-hydrostatic actuators(EHAs)for power,volume,and pressure,there is a growing tendency in the industry to combine the motor and pump to form a so-called'motor pump'to improve the *** this paper,a novel structure for a wet three-phase high-speed reluctance motor pump is proposed,which can further improve integration by removing the dynamic seal on the pump shaft,thereby avoiding the problems of dynamic seal wear and oil leakage and improving heat dissipation under high-speed working ***,after the motor is wetted,the churning loss caused by immersion of the rotor in the oil causes additional fluid resistance *** on fundamental fluid mechanics,an analytical model of the churning torque of a wet motor was *** verify the accuracy of the analytical model,a simulation model of churning loss was established based on computational fluid dynamics(CFD),and the churning torque and flow field state were ***,an experimental prototype was designed and manufactured,and a test bench for churning loss was *** oil churning torque was measured at different speeds and *** results from the analytical,simulation,and experimental models agreed *** experimental results validated the analytical model and CFD *** research provides a practical method for calculating the churning loss and serves as guidance for future optimization of churning loss reduction.

关键词： Motor pump Wet motor Churning loss Analytical model Computational fluid dynamics(CFD)