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Layered Structural PBAT Composite Foams for Efficient Electromagnetic Interference Shielding

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Nano-Micro Letters 2024年第2期16卷 273-286页

作者： Jianming Yang Hu Wang Yali Zhang Hexin Zhang Junwei gu School of Chemistry and Chemical Engineering Anhui University of TechnologyMa’anshanAnhui 243032People’s Republic of China Shaanxi Key Laboratory of Macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an 710072ShaanxiPeople’s Republic of China School of Materials Science and Engineering Jiangsu University of Science and TechnologyZhenjiang 212003JiangsuPeople’s Republic of China

The utilization of eco-friendly,lightweight,high-efficiency and high-absorbing electromagnetic interference(EMI)shielding composites is imperative in light of the worldwide promotion of sustainable *** this work,magnetic poly(butyleneadipate-coterephthalate)(PBAT)microspheres were firstly synthesized via phase separation method,then PBAT composite foams with layered structure was constructed through the supercritical carbon dioxide foaming and scraping *** merits of integrating ferroferric oxideloaded multi-walled carbon nanotubes(Fe3O4@MWCNTs)nanoparticles,a microcellular framework,and a highly conductive silver layer have been judiciously orchestrated within this distinctive layered *** are consumed throughout the process of“absorption-reflection-reabsorption”as much as possible,which greatly declines the secondary radiation *** biodegradable PBAT composite foams achieved an EMI shielding effectiveness of up to 68 dB and an absorptivity of 77%,and authenticated favorable stabilization after the tape adhesion experiment.

关键词： Electromagnetic interference shielding Layered structure Supercritical carbon dioxide foaming Poly(butyleneadipateco-terephthalate) Microcellular

Ultrahigh performance passive radiative cooling by hybrid polar dielectric metasurface thermal emitters

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Opto-Electronic Advances 2024年第4期7卷 17-25页

作者： Yinan Zhang Yinggang Chen Tong Wang Qian Zhu Min gu Institute of Photonic Chips University of Shanghai for Science and TechnologyShanghai 200093China Centre for Artificial-Intelligence Nanophotonics School of Optical-Electrical and Computer EngineeringUniversity of Shanghai for Science and TechnologyShanghai 200093China

Real-world passive radiative cooling requires highly emissive,selective,and omnidirectional thermal emitters to maintain the radiative cooler at a certain temperature below the ambient temperature while maximizing the net cooling *** various selective thermal emitters have been demonstrated,it is still challenging to achieve these conditions sim-ultaneously because of the extreme difficulty in controlling thermal emission of photonic structures in *** we demonstrated hybrid polar dielectric metasurface thermal emitters with machine learning inverse design,en-abling a high emissivity of~0.92 within the atmospheric transparency window 8-13μm,a large spectral selectivity of~1.8 and a wide emission angle up to 80 degrees,*** selective and omnidirectional thermal emitter has led to a new record of temperature reduction as large as~15.4°C under strong solar irradiation of~800 W/m2,signific-antly surpassing the state-of-the-art *** designed structures also show great potential in tackling the urban heat island effect,with modelling results suggesting a large energy saving and deployment area *** research will make significant impact on passive radiative cooling,thermal energy photonics and tackling global climate change.

关键词： radiative cooling dielectric metasurfaces machine learning thermal emitters

Effect of fore/aft-loaded rotor on compressor stability under inlet circumferential distortion

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Chinese Journal of Aeronautics 2024年第5期37卷 199-213页

作者： Dakun SUN Benhao gu Fangfei NING Dengke XU Xiaofeng SUN School of Energy and Power Engineering Beihang UniversityBeijing 102206China Research Institute of Aero-engine Beihang UniversityBeijing 102206China

A modified small perturbation stability prediction model for axial compressors with circumferential inlet distortions is established and applied to investigate the effect of fore/aft-loaded rotor on compressor stability under circumferentially distorted inlet *** inlet total pressure distribution downstream of the distortion screen is measured in experiments and employed for simulations which are implemented via time-space spectral *** stall inception prediction results via the stability model indicate that the compressor with aft-loaded rotor not only performs better in terms of stability under uniform inlet,but also maintains a larger stability margin under circumferentially distorted *** experiments for compressors with fore-loaded and aft-loaded rotor are respectively carried *** results validate the reliability of numerical simulations and the predicted conclusion that the aft-loaded rotor is beneficial for compressor ***,the ability of the developed theoretical model for compressor stability prediction under circumferential distortions is *** addition,dynamic pressure signals at rotor tip measured in experiments illustrate that the circumferential distortion has little effect on the compressor stall pattern.

关键词： Axial compressor stability Inlet distortion Blade loading Small perturbation Time-space spectral method

High Dynamic Bounding and Jumping Motion of Quadruped Robot Based on Stable Optimization Control

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Journal of Bionic Engineering 2024年第1期21卷 101-111页

作者： Sai gu Fei Meng Botao Liu Junyao Gao Qiang Huang School of Mechatronical Engineering Beijing Institute of Technology100081 BeijingChina Key Laboratory of Biomimetic Robots and Systems Ministry of EducationBeijing 100081China

Aiming at the environment such as ravines and obstacles that may be encountered in the actual movement,this paper proposes a method for optimizing the bounding and jumping motion based on the ground touching force trajectory and the air motion trajectory of the quadruped *** method of optimizing the ground reaction force according to the speed of the demand and the height of the jump,and adjusting the stance and swing time according to the relationship of dynamics and momentum *** the same time,under the constraints of dynamics and energy consumption of the robot system,considering the jumping distance and height,a method for optimizing the air trajectory of bounding and jumping is *** switching and landing stability control are also ***,the experimental results show that the quadruped robot has strong bounding and jumping ability,and has achieved stable bounding movement and forward jump movement of 0.8 m.

关键词： Quadruped robot High dynamic motion control-Periodic limit cycle Trajectory optimization

Achieving High Strength and Tensile Ductility in Pure Nickel by Cryorolling with Subsequent Low-Temperature Short-Time Annealing

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Engineering 2024年第2期33卷 190-203页

作者： Zhide Li Hao gu Kaiguang Luo Charlie Kong Hailiang Yu Light Alloys Research Institute Central South UniversityChangsha 410083China State Key Laboratory of High Performance Complex Manufacturing Central South UniversityChangsha 410083China College of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China Electron Microscope Unit University of New South WalesSydneyNSW 2052Australia

Ultra fine-grained pure metals and their alloys have high strength and low *** this study,cryorolling under different strains followed by low-temperature short-time annealing was used to fabricate pure nickel sheets combining high strength with good *** results show that,for different cryorolling strains,the uniform elongation was greatly increased without sacrificing the strength after annealing.A yield strength of 607 MPa and a uniform elongation of 11.7%were obtained after annealing at a small cryorolling strain(ε=0.22),while annealing at a large cryorolling strain(ε=1.6)resulted in a yield strength of 990 MPa and a uniform elongation of 6.4%.X-ray diffraction(XRD),transmission electron microscopy(TEM),scanning electron microscopy(SEM),and electron backscattered diffraction(EBSD)were used to characterize the microstructure of the specimens and showed that the high strength could be attributed to strain hardening during cryorolling,with an additional contribution from grain refinement and the formation of dislocation *** high ductility could be attributed to annealing twins and micro-shear bands during stretching,which improved the strain hardening *** results show that the synergistic effect of strength and ductility can be regulated through low-temperature short-time annealing with different cryorolling strains,which provides a new reference for the design of future thermo-mechanical processes.

关键词： Cryorolling Annealing Nickel Strain hardening Ductility

Indefinite metacavities coupled to a mirror:bound states in the continuum with anomalous resonance scaling

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Photonics Research 2024年第3期12卷 598-607页

作者： QIANG ZHANG PEIXIANG LI ZHIYUAN gu SHAODING LIU ZEJUN DUAN College of Electronic Information and Optical Engineering Taiyuan University of TechnologyTaiyuan 030024China Key Laboratory of Advanced Transducers and Intelligent Control System Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024China

Indefinite metacavities(IMCs)made of hyperbolic metamaterials show great advantages in terms of extremely small mode volume due to large wave vectors endowed by the unique hyperbolic ***,quality(Q)factors of IMCs are limited by Ohmic loss of metals and radiative loss of leaked *** the fact that Ohmic loss of metals is inevitable in IMCs,the radiative loss can be further suppressed by leakage *** we propose a mirror coupled IMC structure which is able to operate at Fabry–Pérot bound states in the continuum(BICs)while the hyperbolic nature of IMCs is *** the BIC point,the radiative loss of magnetic dipolar cavity modes in IMCs is completely absent,resulting in a considerably increased Q factor(>90).Deviating from the BIC point,perfect absorption bands(>0.99)along with a strong near-field intensity enhancement(>1.8×10^(4))appear when the condition of critical coupling is almost *** proposed BICs are robust to the geometry and material composition of IMCs and anomalous scaling law of resonance is verified during the tuning of optical *** also demonstrate that the Purcell effect of the structure can be significantly improved under BIC and quasi-BIC regimes due to the further enhanced Q factor to mode volume *** results provide a new train of thought to design ultra-small optical nanocavities that may find many applications benefitting from strong light–matter interactions.

关键词： hyperbolic mirror definite

Built-in electric field induced S-scheme g-C_(3)N_(4)homojunction for efficient photocatalytic hydrogen evolution:Interfacial engineering and morphology control

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Nano Research 2024年第6期17卷 4961-4970页

作者： Yongpan gu Yike Li Haoqiang Feng Yanan Han Zhongjun Li College of Chemistry Zhengzhou UniversityZhengzhou 450001China

S-scheme possesses superior redox capabilities compared with the II-scheme,providing an effective method to solve the innate defects of g-C_(3)N_(4)(CN).In this study,S-doped g-C_(3)N_(4)/g-C_(3)N_(4)(SCN-tm/CN)S-scheme homojunction was constructed by rationally integrating morphology control with interfacial engineering to enhance the photocatalytic hydrogen evolution ***-situ Kelvin probe force microscopy(KPFM)confirms the transport of photo-generated electrons from CN to *** functional theory(DFT)calculations reveal that the generation of a built-in electric field between SCN and CN enables the carrier separation to be more efficient and *** transient absorption spectrum(fs-TAS)indicates prolonged lifetimes of SCN-tm/CN_(3)(τ1:9.7,τ2:110,andτ3:1343.5 ps)in comparison to those of CN(τ1:4.86,τ2:55.2,andτ3:927 ps),signifying that the construction of homojunction promotes the separation and transport of electron hole pairs,thus favoring the photocatalytic *** visible light irradiation,the optimized SCN-tm/CN_(3)exhibits excellent photocatalytic activity with the hydrogen evolution rate of 5407.3μmol·g^(−1)·h^(−1),which is 20.4 times higher than that of CN(265.7μmol·g^(−1)·h^(−1)).Moreover,the homojunction also displays an apparent quantum efficiency of 26.8%at 435 nm as well as ultra-long and ultra-stable cycle *** work offers a new strategy to construct highly efficient photocatalysts based on the metal-free conjugated polymeric CN for realizing solar energy conversion.

关键词： homojunction built-in electric field morphology control interfacial engineering carrier separation

Carbon sink response of terrestrial vegetation ecosystems in the Yangtze River Delta and its driving mechanism

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Journal of Geographical Sciences 2024年第1期34卷 112-130页

作者： ZHAO Haixia FAN Jinding gu Binjie CHEN Yijiang Nanjing Institute of Geography and Limnology CASNanjing 210008China School of Environmental Science and Engineering Suzhou University of Science and TechnologySuzhou 215009JiangsuChina Nanjing College University of Chinese Academy of SciencesNanjing 211135China School of Agricultural and Food Science The University of QueenslandQueensland 4072Australia

The carbon cycle of terrestrial ecosystems is influenced by global climate change and human *** remote sensing data and land cover products,the spatio-temporal variation characteristics and trends of NEP in the Yangtze River Delta from 2000 to 2020 were analyzed based on the soil respiration *** driving influences of ecosystem structure evolution,temperature,rainfall,and human activities on NEP were *** results show that the NEP shows an overall distribution pattern of high in the southeast and low in the *** area of carbon sinks is larger than that of the carbon *** spatial heterogeneity is *** change trend is basically unchanged or significantly *** future change trend in most areas will be continuous *** with temperature,NEP are more sensitive to *** positive influence of human activities on NEP is mainly observed in north-central Anhui and northern Jiangsu coastal areas,while the negative influence is mainly found in highly urbanized *** the process of ecosystem structure,the contribution of unchanged areas to NEP change is greater than that of changed areas.

关键词： carbon sinks terrestrial vegetation ecosystems driving mechanisms climate change human activities ecosystem structure Yangtze River Delta

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无人集群智能协同仿真试验评估理论框架研究

系统仿真学报 2024年第4期36卷 795-804页

作者：王积鹏张兴吴浩谷雨杨慧杰中国电子科技集团有限公司电子科学研究院北京100041

智能无人集群装备作为智能装备的典型代表,其技术、装备、作战应用在全球范围内加速推进,但总体上无人集群试验理论的研究滞后于无人集群技术、装备,无人集群能力的涌现性、对抗的复杂性,以及无人集群试验的不可重复、不可泛化等特性给... 详细信息

智能无人集群装备作为智能装备的典型代表,其技术、装备、作战应用在全球范围内加速推进,但总体上无人集群试验理论的研究滞后于无人集群技术、装备,无人集群能力的涌现性、对抗的复杂性,以及无人集群试验的不可重复、不可泛化等特性给无人集群试验基础理论、方法带来了巨大挑战。从体系工程集成试验视角和装备研制建设全生命周期视角提出面向能力生长的智能技术、智能单装、智能集群、智能体系4个集群试验模式,深度剖析无人集群智能协同试验的基础理论问题,构建无人集群智能协同试验基础理论框架。

关键词：无人集群智能协同智能技术试验智能单装试验智能集群试验智能体系试验

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