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Effects of aggregate size distribution and carbon nanotubes on the mechanical properties of cemented gangue backfill samples under true triaxial compression

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 311-324页

作者： Qian Yin Fan Wen Zhigang Tao Hai Pu Tianci Deng Yaoyao Meng Qingbin Meng Hongwen Jing Bo Meng Jiangyu Wu State key laboratory of intelligent Construction and Healthy operation and maintenance of Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China State key laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and TechnologyHuainan 232001China State key laboratory for Geomechanics&Deep Underground Engineering China University of Mining and Technology(Beijing)Beijing 100083China key laboratory of Xinjiang Coal Resources Green Mining Ministry of EducationXinjiang Institute of EngineeringUrumqi 830023China

The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious ***,the true triaxial compression tests,CT scanning,SEM,and EDS tests were conducted on cemented gangue backfill samples(CGBSs)with various carbon nanotube concentrations(P_(CNT))that satisfied fractal theory for the PSD of *** mechanical properties,energy dissipations,and failure mechanisms of the CGBSs under true triaxial compression were systematically *** results indicate that appropriate carbon nanotubes(CNTs)effectively enhance the mechanical properties and energy dissipations of CGBSs through micropore filling and microcrack bridging,and the optimal effect appears at P_(CNT)of 0.08wt%.Taking PSD fractal dimension(D)of 2.500 as an example,compared to that of CGBS without CNT,the peak strength(σ_(p)),axial peak strain(ε_(1,p)),elastic strain energy(Ue),and dissipated energy(U_(d))increased by 12.76%,29.60%,19.05%,and90.39%,***,excessive CNTs can reduce the mechanical properties of CGBSs due to CNT agglomeration,manifesting a decrease inρ_(p),ε_(1,p),and the volumetric strain increment(Δε_(v))when P_(CNT)increases from 0.08wt%to 0.12wt%.Moreover,the addition of CNTs improved the integrity of CGBS after macroscopic failure,and crack extension in CGBSs appeared in two modes:detour and pass through the ***σ_(p)and U_(d)firstly increase and then decrease with increasing D,and porosity shows the opposite ***ε_(1,p)andΔε_(v)are negatively correlated with D,and CGBS with D=2.150 has the maximum deformation parameters(ε_(1,p)=0.05079,Δε_(v)=0.01990)due to the frictional slip effect caused by coarse *** increasing D,the failure modes of CGBSs are sequentially manifested as oblique shear failure,"Y-shaped"shear failure,and conjugate shear failure.

关键词： cemented gangue backfill materials particle size distribution true triaxial compression test carbon nanotubes mechanical properties failure modes

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AHLNet:Adaptive Multihead Structure and Lightweight Feature Pyramid Network for Detection of Live Working in Substations

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Machine Intelligence Research 2024年第5期21卷 983-992页

作者： Mengle Peng Xiaoyong Jiang Langyue Huang Zhongyi Li Haiteng Wu Xiaotang Geng zhejiang University of Science and Technology Hangzhou310023China zhejiang key laboratory of intelligent operation and maintenance robot Hangzhou311100China

With the increasing demand for power in society,there is much live equipment in substations,and the safety and standardization of live working of workers are facing *** at these problems of scene complexity and object diversity in the real-time detection of the live working safety of substation workers,an adaptive multihead structure and lightweight feature pyramid-based network(AHLNet)is proposed in this study,which is based on ***,we take AH-Darknet53 as the backbone network of YOLOV3,which can introduce an adaptive multihead(AMH)structure,reduce the number of network parameters,and improve the feature extraction ability of the backbone ***,to reduce the number of convolution layers of the deeper feature map,a lightweight feature pyramid network(LFPN)is proposed,which can perform feature fusion in advance to alleviate the problem of feature imbalance and gradient ***,the proposed AHLNet is evaluated on the datasets of 16 categories of substation safety operation scenarios,and the average prediction accuracy MAP_(50)reaches 82.10%.Compared with YOLOV3,MAP_(50)is increased by 2.43%,and the number of parameters is 90 M,which is only 38%of the number of parameters of *** addition,the detection speed is basically the same as that of YOLOV3,which can meet the real-time and accurate detection requirements for the safe operation of substation staff.

关键词： Adaptive multihead structure lightweight feature pyramid substation feature imbalance multiobject detection

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Revitalizing Human-robot Interaction: Phygital Twin Driven robot Avatar for China-Sweden Teleoperation

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Chinese Journal of Mechanical Engineering 2023年第5期36卷 1-6页

作者： Huiying Zhou Honghao Lv Ruohan Wang Haiteng Wu Geng Yang State key laboratory of Fluid Power and Mechatronic Systems School of Mechanical EngineeringZhejiang UniversityHangzhou 310027China Hangzhou Shenhao Technology Co. Ltd.Hangzhou 310000China zhejiang key laboratory of intelligent operation and maintenance robot Hangzhou 310000China

1 Introduction Digital Twin(DT)is built and maintained in the digital rather physical realm[1,2].Dynamic DT mirrors the exact state of the physical system by means of multidimensional models describing the behavior of physical entity,and sensors providing the real-time coupling to models[3].Te outbreak of COVID-19 pandemic results in speeding up the virtualization and digitization of the physical entity with the support from ***,quarantine and division led by COVID-19 pandemic make human beings’eyes for the physical interaction become more *** physical world and the digital world are becoming interwoven,which indicates a new opportunity towards phygital *** is so often the question:how can I get closer to my distant companion?How can I extend my service or emotional concern to facilitate interaction in spite of space obstruction?Tese questions deserve thinking as a lesson learned from outbreak of COVID-19 pandemic.

关键词： Twin robot closer

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Nitrogen-doped porous carbons from polyacrylonitrile fiber as effective CO_(2) adsorbents

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Journal of Environmental Sciences 2023年第3期125卷 533-543页

作者： Changdan Ma Jiali Bai Xin Hu Zhuohan Jiang Linlin Wang key laboratory of the Ministry of Education for Advanced Catalysis Materials Zhejiang Normal UniversityJinhua 321004China key laboratory of Urban Rail Transit intelligent operation and maintenance Technology and Equipment of zhejiang Province College of EngineeringZhejiang Normal UniversityJinhua 321004China

In this report, nitrogen-doped porous carbons were synthesized from polyacrylonitrile fiber by a facile two-step synthesis process i.e. carbonization followed by KOH activation. Activation temperature and KOH/carbon ratio are two parameters to tune the porosity and surface chemical properties of sorbents. The as-obtained sorbents were carefully *** attention was paid concerning the change of sorbents’ morphology with respect to synthesis conditions. Under the activation temperatures of this study, the sorbents can still retain their fibrous structure when the KOH/carbon mass ratio is 1. Further increasing the KOH amount will destroy the original morphology of polyacrylonitrile fiber. CO_(2)adsorption performance tests show that a sorbent retaining the fibrous shape possesses the highest CO_(2)uptake of 3.95 mmol/g at 25℃and 1 bar. Comprehensive investigation found that the mutual effect of narrow microporosity and doped N content govern the CO_(2)adsorption capacity of these adsorbents. Furthermore, these polyacrylonitrile fiber-derived carbons present multiple outstanding CO_(2)capture properties such as excellent recyclability, high CO_(2)/N_(2)selectivity, fast adsorption kinetics, suitable heat of adsorption, and good dynamic adsorption capacity. Hence, nitrogen-doped porous carbons with fibrous structure are promising in CO_(2)capture.

关键词： CO_(2)adsorption Nitrogen-doping porous carbon Fibrous morphology Polyacrylonitrile fiber KOH activation

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An effective nonlinear dynamic formulation to analyze grasping capability of soft pneumatic robotic gripper

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International Journal of Smart and Nano Materials 2024年第3期15卷 405-431页

作者： Qiping Xu Chenhang Ying Kehang Zhang Huiyu Xie Shiju E Department of robotics Engineering Key Laboratory of Urban Rail Transit Intelligent Operation and Maintenance Technology&Equipment of Zhejiang ProvinceCollege of EngineeringZhejiang Normal UniversityJinhuaP.R.China

Soft pneumatic robotic grippers have found extensive applica-tions across various engineering domains,which prompts active research due to their splendid compliance,high flex-ibility,and safe human-robot interaction over conventional stiff *** simplified rod-based models prin-cipally focused on clarifying overall large deformation and bending postures of soft grippers from static or quasi-static perspectives,whereas it is challenging to elaborate grasping characteristics of soft grippers without considering contact interaction and nonlinear large deformation *** address this,based on absolute nodal coordinate formulation(ANCF),comprehensively allowing for structural complexity,geometric,material and boundary nonlinearities,and incorpor-ating Coulomb’friction law with a multiple-point contact method,we put forward an effective nonlinear dynamic mod-eling approach for exploring grasping capability of soft ***,we solved the established dynamic equations using Generalized-αscheme,and conducted thorough numer-ical simulation analysis on a three-jaw soft pneumatic gripper(SPG)in terms of grasping configurations,displacements and contact *** proposed dynamic approach can accurately both describe complicated deformed configurations along with stress distribution and provide a feasible solution to simulate grasping targets,whose effectiveness and precision were analyzed theoretically and verified experimentally,which may shed new light on devising and optimizing other multi-functional SPGs.

关键词： Nonlinear dynamic formulation soft pneumatic robotic grippers contact interaction grasping capability configuration variations

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A comparative investigation on wear behaviors of physical and chemical vapor deposited bronze coatings for hydraulic piston pump

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Chinese Journal of Aeronautics 2024年第3期37卷 391-403页

作者： Wei HAO Andrews LARBI Hongkang DONG Dongyun WANG Shenghu LI zhejiang Provincial key laboratory of Urban Rail Transit intelligent operation and maintenance Technology and Equipment Zhejiang Normal UniversityJinhua 321004China College of Engineering Zhejiang Normal UniversityJinhua 321004China Hangzhou Lilong Hydraulic Co. LtdHangzhou 311200China

The cylinder block/valve plate interface is one of the most critical frictional interfaces of the swashplate-type axial piston ***,the poor lubrication interface caused rapid wear and high friction loss in an elastohydrodynamic lubrication system,decreasing the pump *** resistant bronze coatings were fabricated on 38CrMoAl substrate by Physical Vapor Deposition(PVD)and Chemical Vapor Deposition(CVD),***-on-disc wear tests were performed to comparatively investigate the wear behaviors of the coatings and bulk ductile iron *** can be found that the PVD-bronze coating exhibited better wear resistance than the other two *** enhanced wear resistance was attributed to the unique composite microstructure and desired mechanical strength,which could resist to mechanical shear and spallation,decreasing friction *** appropriate hardness of(1.33±0.07)GPa could be beneficial for enhancing its wear *** PVD-bronze coating possessed a much lower and stable coefficient of friction(about 0.1)and wear rate(about 6000μm3.N-1.m-1)under the loading forces of about 100 N after 20 *** wear mechanism was the abrasive wear.

关键词： Aircraft hydraulic pump Bronze Coatings Wear resistance Mechanisms

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A Novel Bionic Piezoelectric Actuator Based on the Walrus Motion

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Journal of Bionic Engineering 2021年第5期18卷 1117-1125页

作者： Jianping Li Junjie Cai Nen Wan Yili Hu Jianming Wen Junwu Kan Song Chen Hongwei Zhao key laboratory of Urban Rail Transit intelligent operation and maintenance Technology and Equipment of zhejiang Provincial The Institute of Precision Machinery and Smart StructureCollege of EngineeringZhejiang Normal UniversityJinhua 321004China School of Mechanical and Aerospace Engineering Jilin UniversityChangchun 130025China

A novel bionic piezoelectric actuator based on the walrus motion to achieve high performance on large working stroke for micro/nano positioning systems is first proposed in this *** structure of the proposed walrus type piezoelectric actuator is described,and its motion principle is presented in *** experimental system is set up to verify its feasibility and explore its working *** results indicate that the proposed walrus type piezoelectric actuator could realize large working stroke with only one driving unit and one coupled clamping unit;the maximum stepping displacement isΔL max=19.5μm in the case that the frequency f=1 Hz and the voltage U=120 V;the maximum speed V max=2275.2μm·s^(-1) when the frequency f=900 Hz and the voltage U=120 V;the maximum vertical load m max=350 g while the voltage U=120 V and the frequency f=1 *** study shows the feasibility of mimicking the bionic motion of the real walrus animal to the design of piezoelectric actuators,which is hopeful for the real application of micro/nano positioning systems to achieve large working stroke and high performance.

关键词： Piezoelectric actuator Bionic actuator Walrus motion Flexure mechanism

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High-performance wearable bimetallic nanowire-assisted composite foams for efficient electromagnetic interference shielding,infrared stealth,and piezoresistive sensing

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Nano Research 2024年第7期17卷 6757-6765页

作者： Tianyi Hang Lijie Zhou Chenhui Xu Yiming Chen Jiahui Shen Jiajia Zheng Pingan Yang Xiping Li Heng Luo Guoxiu Tong key laboratory of Urban Rail Transit intelligent operation and maintenance Technology and Equipment of zhejiang Province College of EngineeringZhejiang Normal UniversityJinhua 321004China School of Automation Chongqing University of Posts and TelecommunicationsChongqing 400065China State key laboratory of Powder Metallurgy Central South UniversityChangsha 410083China key laboratory of the Ministry of Education for Advanced Catalysis Materials College of Chemistry and Materials ScienceZhejiang Normal UniversityJinhua 321004China

With the accelerated development of modern detection and communication technology,the multifunctional wearable materials with excellent electromagnetic interference(EMI)shielding,infrared stealth,and human monitoring for improving military combat capability have received extensive *** this work,the lightweight melamine foam(MF)@silver nanowires(AgNWs)-iron nanowires(FeNWs)(AgFe-MF)was fabricated by a vacuum-assisted dip-coating *** to the porous structure and synergistic electrical and magnetic losses,this lightweight(0.115 g/cm^(3))composite foam with an ultra-low filler content(0.62 vol.%)exhibited an ideal EMI shielding efficiency of 38.4 *** the other hand,the AgFe-MF realized a powerful multifunctional *** surface saturation temperature of the AgFe-MF reached 94.2℃under a low applied voltage of 1.8 V and remained extremely fast heating and cooling response and terrific working stability,resulting in excellent infrared stealth and camouflage ***,taking virtues of the elastic porous conductive architecture,the AgFe-MF was utilized as a piezoresistive sensor exhibiting board compressive interval of 0–1.62 kPa(50%strain)with a good sensitivity of 0.57 kPa^(−1).This work will provide new ideas and insights for developing multifunctional wearable devices in the fields of EMI shielding,thermal management,and piezoresistive sensing.

关键词： metal nanowires porous foams electromagnetic interference shielding infrared stealth wearable sensors

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Toughened (Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2)–SiC composites fabricated by one-step reactive sintering with a unique SiB_(6) additive

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Journal of Advanced Ceramics 2024年第1期13卷 86-100页

作者： Wei Hao Xinzhe Lu Ling Li Tao Wang Guoliang Ren Huangyue Cai Xiaofeng Zhao Dongyun Wang Na Ni zhejiang Provincial key laboratory of Urban Rail Transit intelligent operation and maintenance Technology&Equipment Zhejiang Normal UniversityZhejiang 321004China key Lab of Education Ministry for Power Machinery and Engineering School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China

High-entropy diboride has been arousing considerable interest in recent ***,the low toughness and damage tolerance limit its applications as ultra-high-temperature structural *** we report that a unique SiB_(6) additive has been first incorporated as boron and silicon sources to fabricate a high-entropy boride(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2)–SiC composite though one-step boro/carbothermal reduction reactive sintering.A synergetic effect of high-entropy sluggish diffusion and SiC secondary phase retarded the grain growth of the(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2)–51SiC *** small grain size was beneficial to shorten the diffusion path for mass transport,thereby enhancing the relative density to~99.3%.These results in an increase of fracture toughness from~5.2 in HEBS-1900 to~7.7 MPa·m^(1/2) in HEBS-2000,which corresponded to a large improvement of 48%.The improvement was attributed to a mixed mode of intergranular and transgranular cracking for offering effective pinning in crack propagation,resulting from balanced grain boundary strength collectively affected by improved densification,solid solution strengthening,and incorporation of SiC secondary phase.

关键词： high-entropy diboride silicon hexaboride boro/carbothermal reduction reactive sintering fracture toughness

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Preface for the Special Issue on“Safety and intelligent maintenance of Offshore Structures”

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China Ocean Engineering 2024年第2期38卷 181-182页

作者： XU Wan-hai State key laboratory of Hydraulic Engineering intelligent Construction and operation Tianjin UniversityTianjin 300072China

The ocean serves as a vital carrier for human resource development and economic growth and contains rich mineral resources such as oil,natural gas,polymetallic nodules,cobalt-rich ferromanganese crusts,polymetallic sulfides,and rare earth ***,the ocean has wealthy reserves of wind,wave,tidal,and solar energy,making it an essential strategic space for sustainable future ***,offshore structures are complex.

关键词： ocean offshore tidal

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