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Tsinghua Science and technology 2024年第2期29卷 368-385页

作者： Canyun Dai Xiaoyan Sun Hejuan Hu Yong Zhang Dunwei Gong School of Information and Control Engineering China University of Mining and TechnologyXuzhou 221116China School of Information Science and technology Qingdao University of Science and TechnologyQingdao 266061China

The dispatch of integrated energy systems in coal mines(IES-CM)with mine-associated supplies is vital for efficient energy utilization and carbon emissions ***,IES-CM dispatch is highly challenging due to its feature as multi-objective and strong *** constrained multi-objective evolutionary algorithms often fall into locally feasible domains with poorly distributed Pareto front,which greatly deteriorates dispatch *** tackle this problem,we transform the traditional dispatch model of IES-CM into two tasks:the main task with all constraints and the helper task with constraint *** we propose a constraint adaptive multi-tasking differential evolution algorithm(CA-MTDE)to optimize these two tasks *** helper task with constraint adaptive is developed to obtain infeasible solutions near the feasible *** purpose of this infeasible solution is to transfer guiding knowledge to help the main task move away from local ***,a dynamic dual-learning strategy using DE/current-to-rand/1 and DE/current-to-best/1 is developed to maintain task diversity and ***,we comprehensively evaluate the performance of CA-MTDE by applying it to a coal mine in Shanxi Province,considering two IES-CM *** demonstrate the feasibility of CA-MTDE and its ability to generate a Pareto front with exceptional convergence,diversity,and distribution.

关键词： dispatch integrated energy system coal mine evolutionary multi-tasking constraint differential evolution

Nonreciprocal thermal metamaterials:Methods and applications

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1678-1693页

作者： Zhengjiao Xu Chuanbao Liu Xueqian Wang Yongliang Li Yang Bai Institute for Advanced Material and technology University of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China

Nonreciprocity of thermal metamaterials has significant application prospects in isolation protection,unidirectional transmission,and energy ***,due to the inherent isotropic diffusion law of heat flow,it is extremely difficult to achieve nonreciprocity of heat *** review presents the recent developments in thermal nonreciprocity and explores the fundamental theories,which underpin the design of nonreciprocal thermal metamaterials,i.e.,the Onsager reciprocity ***,three methods for achieving nonreciprocal metamaterials in the thermal field are elucidated,namely,nonlinearity,spatiotemporal modulation,and angular momentum bias,and the applications of nonreciprocal thermal metamaterials are *** also discuss nonreciprocal thermal ***,the potential applications of nonreciprocity to other Laplacian physical fields are ***,the prospects for advancing nonreciprocal thermal metamaterials are highlighted,including developments in device design and manufacturing techniques and machine learning-assisted material design.

关键词： thermal metamaterials nonreciprocity nonlinearity spatiotemporal modulation

Balanced Fracturing and Cold-welding of Magnesium during Ball Milling Assisted by Carbon Coating:Experimental and Molecular Dynamic Simulation

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Journal of Wuhan university of technology(Materials Science) 2024年第4期39卷 895-903页

作者：韩宗盈 DONG Hui DING Guoyang ZHANG Jiale SONG Xiufang College of Energy Storage technology Shandong University of Science and TechnologyQingdao 266590China College of Chemical and Biological Engineering Shandong University of Science and TechnologyQingdao 266590China

The lignite-derived carbon from self-protection pyrolysis was employed to balance the fracturing and cold-welding of magnesium during ball *** size analysis indicates that the introduction of lignite-derived carbon can effectively reduce the particle size of Mg while the introduction of graphite does no ***,the effect of lignite-derived carbon on crystallite size reduction of Mg is also better than graphite.A moderate cold-welding phenomenon was observed after ball-milling Mg with the lignite-derived carbon,suggesting less Mg is wasted on the milling vials and *** dynamic simulations reveal that the balanced fracturing and cold-welding of magnesium during ball milling is mainly attributed to the special structure of the lignite-derived carbon:graphitized short-range ordered stacking function as dry lubricant and irregular shape/sharp edge function as milling *** preliminary findings in current study are expected to offer implications for designing efficient Mg-based hydrogen storage materials.

关键词： magnesium lignite-derived carbon cold-welding ball milling molecular dynamic

Fixed-time stabilization of output-constrained stochastic high-order nonlinear systems

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Science China(Information Sciences) 2024年第4期67卷 5-20页

作者： Ruiming XIE Shengyuan XU Nanjing university of Science and technology School of Automation

In this study, the fixed-time stabilization problem of stochastic high-order nonlinear systems with output constraint and high-order and low-order nonlinearities is addressed. A new coordinate transformation is employed to directly convert output-constrained stochastic systems into an equivalent unconstrained *** fully extracting the characteristics of system nonlinearities and using the stochastic fixed-time stability theorem, a new design and analysis method is constructed to guarantee that the trivial solution of the closed-loop system is stochastically fixed-time stable while fulfilling the output constraint.

关键词： stochastic high-order nonlinear system output constraint high-order and low-order nonlinearity fixed-time stabilization finite-time stabilization

Linear shallow neural network to accelerate transmitter dispersion eye closure quaternary(TDECQ) assessment

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Science China(Information Sciences) 2024年第4期67卷 337-338页

作者： Junjiang XIANG Zejun CHEN Yijun CHENG Hailin YANG Xuancheng HUO Meng XIANG Gai ZHOU Yuwen QIN Songnian FU Institute of Advanced Photonics technology School of Information EngineeringGuangdong University of Technology School of Optical and Electronic Information Huazhong University of Science and Technology Key Laboratory of Photonic technology for Integrated Sensing and Communication Ministry of Education of ChinaGuangdong University of Technology Guangdong Provincial Key Laboratory of Information Photonics technology Guangdong University of Technology

To support the ever-emerging capacity requirement of datacenter interconnection(DCI) applications, transmitter dispersion eye closure quaternary(TDECQ) has been proposed by IEEE802.3 standard [1], which is specifically employed for the four-level pulse amplitude modulation(PAM-4) signals. However, the traditional scheme of TDECQ assessment needs several iterative operations,

关键词： IEEE Standards

Skill enhancement learning with knowledge distillation

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Science China(Information Sciences) 2024年第8期67卷 206-220页

作者： Naijun LIU Fuchun SUN Bin FANG Huaping LIU Department of Computer Science and technology Tsinghua University

Skill learning through reinforcement learning has significantly progressed in recent years. However, it often struggles to efficiently find optimal or near-optimal policies due to the inherent trial-and-error exploration in reinforcement learning. Although algorithms have been proposed to enhance skill learning efficacy, there is still much room for improvement in terms of skill learning performance and training stability. In this paper, we propose an algorithm called skill enhancement learning with knowledge distillation(SELKD), which integrates multiple actors and multiple critics for skill learning. SELKD employs knowledge distillation to establish a mutual learning mechanism among actors. To mitigate critic overestimation bias,we introduce a novel target value calculation method. We also perform theoretical analysis to ensure the convergence of SELKD. Finally, experiments are conducted on several continuous control tasks, illustrating the effectiveness of the proposed algorithm.

关键词： skill learning enhancement learning reinforcement learning knowledge distillation

Application of extreme gradient boosting in predicting the viscoelastic characteristics of graphene oxide modified asphalt at medium and high temperatures

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Frontiers of Structural and Civil Engineering 2024年第6期18卷 899-917页

作者： Huong-Giang Thi HOANG Hai-Van Thi MAI Hoang Long NGUYEN Hai-Bang LY university of Transport technology Hanoi 100000Vietnam

Complex modulus(G^(*))is one of the important criteria for asphalt classification according to AASHTO M320-10,and is often used to predict the linear viscoelastic behavior of asphalt *** addition,phase angle(φ)characterizes the deformation resilience of asphalt and is used to assess the ratio between the viscous and elastic *** is thus important to quickly and accurately estimate these two *** purpose of this investigation is to construct an extreme gradient boosting(XGB)model to predict G^(*)andφof graphene oxide(GO)modified asphaltat medium and high *** data sets are gathered from previously published experiments,consisting of 357 samples for G^(*)and 339 samples forφ,and the se are used to develop the XGB model using nine inputs representing theasphalt binder *** findings show that XGB is an excellent predictor of G^(*)andφof GO-modified asphalt,evaluated by the coefficient of determination R^(2)(R^(2)=0.990 and 0.9903 for G^(*)andφ,respectively)and root mean square error(RMSE=31.499 and 1.08 for G^(*)andφ,respectively).In addition,the model’s performance is compared with experimental results and five other machine learning(ML)models to highlight its *** the final step,the Shapley additive explanations(SHAP)value analysis is conducted to assess the impact of each input and the correlation between pairs of important features on asphalt’s two physical properties.

关键词： complex modulus phase angle graphene oxide asphalt extreme gradient boosting machine learning

Span-based joint entity and relation extraction augmented with sequence tagging mechanism

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Science China(Information Sciences) 2024年第5期67卷 84-98页

作者： Bin JI Shasha LI Hao XU Jie YU Jun MA Huijun LIU Jing YANG College of Computer National University of Defense Technology

Span-based joint extraction simultaneously conducts named entity recognition(NER) and relation extraction(RE) in a text span form. However, since previous span-based models rely on span-level classifications, they cannot benefit from token-level label information, which has been proven advantageous for the task. In this paper, we propose a sequence tagging augmented span-based network(STSN), a spanbased joint model that can make use of token-level label information. In STSN, we construct a core neural architecture by deep stacking multiple attention layers, each of which consists of three basic attention *** the one hand, the core architecture enables our model to learn token-level label information via the sequence tagging mechanism and then uses the information in the span-based joint extraction; on the other hand, it establishes a bi-directional information interaction between NER and RE. Experimental results on three benchmark datasets show that STSN consistently outperforms the strongest baselines in terms of F1,creating new state-of-the-art results.

关键词： joint extraction named entity recognition relation extraction span sequence tagging mechanism

Effects of content and particle size of TiH2 powders on the energy output rules of RDX composite explosives

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Defence technology（防务技术） 2024年第2期32卷 297-308页

作者： Hao Wang Yangfan Cheng Shoujun Zhu Zihan Li Zhaowu Shen School of Chemical Engineering Anhui University of Science and TechnologyHuainan 232001China Anhui Engineering Laboratory of Explosive Materials and technology Anhui University of Science and TechnologyHuainan 232001China School of Engineering Science University of Science and Technology of ChinaHefei 230027China

In order to improve the detonation characteristics of RDX,a RDX-based composite explosive with TiH_(2)powders was *** effects of content and particle size of TiH_(2)powders on thermal safety,shock wave parameters and thermal damage effects of RDX-based composite explosive were studied with the C80 microcalorimeter,air blast experiment system and colorimetric thermometry *** results showed that TiH_(2)powders could enhance the thermal stability of RDX-based composite explosive and increase its ultimate decomposition *** content and particle size of TiH_(2)powders also had significant effects on the thermal safety,detonation velocity,shock wave parameters,fireball temperature and duration of RDX-based composite ***,the differences of TiH_(2)and Ti powders on the detonation energy output rules of RDX-based composite explosives were also compared,showing that TiH_(2)powders had better influences on improving the explosion power and thermal damage effect of RDX-based composite explosives than Ti powders,for the participation of free H_(2)released by TiH_(2)powders in the detonation ***_(2)powders have important research values as a novel energetic additive in the field of military composite explosives.

关键词： RDX Hydrogen storage alloy Air blast After-burn reaction Colorimetric thermometry

A flexible ultra-broadband multi-layered absorber working at 2 GHz-40 GHz printed by resistive ink

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Chinese Physics B 2024年第2期33卷 329-333页

作者：汪涛闫玉伦陈巩华李迎胡俊毛剑波 School of Microelectronics Hefei University of TechnologyHefei 230601China Special Display and Imaging technology Innovation Center of Anhui Province Academy of Photoelectric TechnologyHefei University of TechnologyHefei 230027China

A flexible extra broadband metamaterial absorber(MMA)stacked with five layers working at 2 GHz–40 GHz is *** layer is composed of polyvinyl chloride(PVC),polyimide(PI),and a frequency selective surface(FSS),which is printed on PI using conductive *** investigate this absorber,both one-dimensional analogous circuit analysis and three-dimensional full-wave simulation based on a physical model are *** crucial electromagnetic properties,such as absorption,effective impedance,complex permittivity and permeability,electric current distribution and magnetic field distribution at resonant peak points,are studied in *** shows that the working frequency of this absorber covers entire S,C,X,Ku,K and Ka bands with a minimum thickness of 0.098λ_(max)(λ_(max) is the maximum wavelength in the absorption band),and the fractional bandwidth(FBW)reaches 181.1%.Moreover,the reflection coefficient is less than-10 dB at 1.998 GHz–40.056 GHz at normal incidence,and the absorptivity of the plane wave is greater than 80%when the incident angle is smaller than 50°.Furthermore,the proposed absorber is experimentally validated,and the experimental results show good agreement with the simulation results,which demonstrates the potential applicability of this absorber at 2 GHz–40 GHz.

关键词： extra broadband physical model flexible metamaterial absorber multi-layer frequency selective surface