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Vibration response and safety control for blasting vibration of the existing tunnel with defects

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Underground Space 2024年第2期15卷 76-89页

作者： Junying xia Bo wang Xinxin Guo Zhuoxiong Xie Key Laboratory of Transportation Tunnel Engineering Ministry of EducationSouthwest Jiaotong UniversityChengdu 610031China College of Environment and Civil Engineering Chengdu University of TechnologyChengdu 610059China Guangdong Communication Planning&Design Institute Group Co. LtdGuangzhou 510507China

Current studies on blasting construction of small clear-distance tunnels have not considered the impact of existing tunnel lining defects when establishing safety *** paper offers a series of study results based on the blasting project of a new tunnel adjacent to the existing defect Xinling tunnel to thoroughly examine the dynamic response,safety control standards,and measures of the existing defect ***,structural models were developed to investigate the influence of the presence or absence of specific defects(like lining cracks and cavities behind the lining)on the dynamic response of the current tunnel lining to identify the most unfavorable defect ***,establish safety control standards for intact linings and those with the most unfavorable ***,two types of control measures,single safe charge and reasonable delay time,were studied based on the established safety control *** particular,the most adverse position of cracks was the wall facing the explosion,the rise in depth was more unfavorable for vibration response,and the impact of the longitudinal crack was restricted to the vicinity of the *** the vault was the most adverse cavity position,the rise in cavity area was more damaging,and the influence range varied with longitudinal cavity ***,the impact of cracks was mainly evident in the amplification effect of stress at the crack *** contrast,cavities had varied degrees of amplification effects on the vibration velocity and stress response and a relatively extensive influence *** control research was conducted,when the tunnel was intact,with a right wall crack,a vault cavity,and both vault cavity and crack for this project,the peak particle velocity(PPV)of the safety control standard for vibration velocity was 13,10,13,and 8 cm/s,respectively,and the respective single safe charge could be adjusted at 64,53,37,and 25 ***,the presence of different defects had a relati

关键词： Existing tunnel Defect Blasting construction Vibration response Control standards and measures

Harmonic Transfer Function Based Single-input Single-output Impedance Modeling of LCC-HVDC Systems

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Journal of Modern Power Systems and Clean Energy 2024年第4期12卷 1327-1332页

作者： Yang wang Fei xia Ying wang xianyong xiao College of Electrical Engineering Sichuan UniversityChengdu 610065China

This study presents a harmonic transfer function(HTF)based single-input single-output(SISO)impedance modeling *** method converts an HTF from phase domain to sequence domain and then transforms it into an SISO impedance while preserving the frequency coupling information of different sequences and different *** of this method to a line-commutated converter based high-voltage direct current(LCC-HVDC)system are *** results demonstrate the accuracy of the derived SISO impedance,and a truncation-order selection is *** case study shows that the proposed method facilitates simpler impedance measurements and associated stability analysis.

关键词： Line-commutated converter based high-voltage direct current(LCC-HVDC) harmonic transfer function(HTF) single-input single-output(SISO)impedance frequency coupling

Robust boundary-induced bulk propagations in elastic waveguides with nonplanar surfaces

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Science China(Physics,Mechanics & Astronomy) 2024年第4期67卷 88-96页

作者： Baizhan xia Jielong Zhang Zihan Jiang Jianting Liu State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsha 410082China College of Mechanical and Vehicle Engineering Hunan UniversityChangsha 410082China

Trivial elastic waveguides induced by line defects and nontrivial elastic waveguides protected by topological edge states have been extensively examined in planar waveguide *** these investigations,little is known about topologically protected bulk states and their resulting robust transmission properties,especially in nonplanar elastic waveguides with folded,curved,and twisted *** Dirac waveguides with robust boundary-induced bulk states are *** states arise from the truncated boundaries of bulks with linear Dirac conical dispersions,differing from topologically protected edge states ensured by the bulk-edge *** proof is provided,in which boundary-induced bulk states show robustly high-throughput transmissions along the waveguides,even with folded,curved,and twisted *** results not only open up new avenues for examining novel topological phenomena about bulk but also offer new platforms for developing topological devices with nonplanar surfaces.

关键词： elastic waveguides boundary-induced bulk propagations Dirac conical dispersions nonplanar surfaces

Configuration Synthesis and Grasping Performance Analysis of Multi-Loop Coupling Capture Mechanism for Launch and Recovery of Torpedo-Shaped Autonomous Underwater Vehicle

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China Ocean Engineering 2024年第3期38卷 453-466页

作者： ZHANG Guo-xing xia Xin-lu GUO Jin-wei School of Mechanical Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China

Research of capture mechanisms with strong capture adaptability and stable grasp is important to solve the problem of launch and recovery of torpedo-shaped autonomous underwater vehicles(AUVs).A multi-loop coupling capture mechanism with strong adaptability and high retraction rate has been proposed for the launch and recovery of torpedo-shaped AUVs with different morphological ***,the principle of capturing motion retraction is described based on the appearance characteristics of torpedo-shaped AUVs,and the configuration synthesis of the capture mechanism is carried out using the method of constrained chain ***,the screw theory is employed to analyze the degree of freedom(DoF)of the capture ***,the 3D model of the capture mechanism is established,and the kinematics and dynamics simulations are carried *** with the capture orientation requirements of the capture mechanism,the statics and vibration characteristics analyses are carried ***,considering the capture process and the underwater working environment,the motion characteristics and hydraulics characteristics of the capture mechanism are ***,a principle prototype is developed and the torpedo-shaped AUVs capture experiment is *** work provides technical reserves for the research and development of AUV capture special equipment.

关键词： capture mechanism torpedo-shaped AUVs configuration synthesis launch and recovery grasping performance analysis

Intensifying electrified flow-through water treatment technologies via local environment modification

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Frontiers of Environmental Science & Engineering 2024年第6期18卷 17-25页

作者： Zheng-Yang Huo xiaoxiong wang xia Huang Menachem Elimelech School of Environment and Natural Resources Institute of Ecological CivilizationRenmin University of ChinaBeijing 100872China Institute for Ocean Engineering Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China Center of Double Helix Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China Department of Chemical and Environmental Engineering Yale UniversityNew HavenCT 06520-8286USA

Removing high-risk and persistent contaminants from water is challenging,because they typically exist at low concentrations in complex water *** flow-through technologies are viable to overcome the limitations induced by mass transport for efficient contaminant *** the local environment of the flow-through electrodes offers opportunities to further improve the reaction kinetics and selectivity for achieving near-complete removal of these contaminants from ***,we present state-of-the-art local environment modification approaches that can be incorporated into electrified flow-through technologies to intensify water *** first show methods of nanospace incorporation,local geometry adjustment,and microporous structure optimization that can induce spatial confinement,enhanced local electric field,and microperiodic vortex,respectively,for local environment *** then discuss why local environment modification can complement the flow-through electrodes for improving the reaction rate and ***,we outline appropriate scenarios of intensifying electrified flow-through technologies through local environment modification for fit-for-purpose water treatment applications.

关键词： Point-of-use water treatment Electrified membrane Advection-enhanced mass transport water decontamination and disinfection Emerging contaminants

Impact of asymptomatic infected individuals on epidemic transmission dynamics in multiplex networks with partial coupling

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Chinese Physics B 2024年第10期33卷 80-87页

作者： Xin Hu Jiaxing Chen Chengyi xia School of Control Science and Engineering Tiangong UniversityTianjin 300387China School of Computer Science and Engineering Tianjin University of TechnologyTianjin 300384China School of Artificial Intelligence Tiangong UniversityTianjin 300387China

The theory of network science has attracted great interest of many researchers in the realm of biomathematics and public health,and numerous valuable epidemic models have been *** previous studies,it is common to set up a one-to-one correspondence between the nodes of a multi-layer network,ignoring the more complex situations in *** the present work,we explore this situation by setting up a partially coupled model of a two-layer network and investigating the impact of asymptomatic infected individuals on *** propose a self-discovery mechanism for asymptomatic infected individuals,taking into account situations such as nucleic acid testing in the community and individuals performing self-antigen testing during the *** these factors together,through the microscopic Markov chain approach(MMCA)and extensive Monte Carlo(MC)numerical simulations,we find that the greater the coupling between the networks,the more information dissemination is *** order to control the epidemics,more asymptomatic infected individuals should be made aware of their *** adoption of nucleic acid testing and individual adoption of antigenic self-testing can help to contain epidemic ***,the epidemic threshold of the proposed model is derived,and then miscellaneous factors affecting the epidemic threshold are also *** results are conducive to devising the prevention and control policies of pandemics.

关键词： asymptomatic infected individuals multi-layer networks partial interdependence

Facile preparation of Fe/N-based biomass porous carbon composite towards enhancing the thermal decomposition of DAP-4

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Defence Technology（防务技术） 2024年第1期31卷 288-294页

作者： Er-hai An xiao-xia Li Cun-juan Yu Ying-xin Tan Zi-jun Fan Qing-xia Li Peng Deng Xiong Cao School of Environment and Safety Engineering North University of ChinaTaiyuan030051PR China College of Safety and Emergency Management Engineering Taiyuan University of Science and TechnologyTaiyuan030024PR China

Fe/N-based biomass porous carbon composite(Fe/N-p Carbon) was prepared by a facile high-temperature carbonization method from biomass,and the effect of Fe/N-p Carbon on the thermal decomposition of energetic molecular perovskite-based material DAP-4 was *** porous carbonaceous materials was considered as the micro/nano support layers for in situ deposition of Fe/N ***/Np Carbon was prepared simply by the high-temperature carbonization *** was found that it showed the inherent catalysis properties for thermal decomposition of *** heat release of DAP-4/Fe/N-p Carbon by DSC curves tested had increased slightly,compared from DAP-4/Fe/N-p *** decomposition temperature peak of DAP-4 at the presence of Fe/N-p Carbon had reduced by 79°C from384.4°C(pure DAP-4) to 305.4°C(DAP-4/Fe/N-p Carbon-3).The apparent activation energy of DAP-4thermal decomposition also had decreased by 29.1 J/*** possible catalytic decomposition mechanism of DAP-4 with Fe/N-p Carbon was proposed.

关键词： Biomass materials Porous carbon DAP-4 Thermal decomposition Facile method

Joint Optimization of Trajectory and Task Offloading for Cellular-Connected Multi-UAV Mobile Edge Computing

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Chinese Journal of Electronics 2024年第3期33卷 823-832页

作者： Jingming xia Yufeng LIU Ling TAN School of Artificial Intelligence Nanjing University of Information Science and Technology Engineering Research Center of Digital Forensics Ministry of Education Nanjing University of Information Science and Technology

Since the computing capacity and battery energy of unmanned aerial vehicle(UAV) are constrained,UAV as aerial user is hard to handle the high computational complexity and time-sensitive *** paper investigates a cellular-connected multi-UAV network supported by mobile edge *** UAVs carrying tasks fly from a given initial position to a termination position within a specified *** handle the large number of tasks carried by UAVs,we propose a energy cost of all UAVs based problem to determine how many tasks should be offloaded to high-altitude balloons(HABs) for computing,where UAV-HAB association,the trajectory of UAV,and calculation task splitting are jointly ***,the formulated problem has nonconvex ***,an efficient iterative algorithm by applying successive convex approximation and the block coordinate descent methods is put ***,in each iteration,the UAV-HAB association,calculation task splitting,and UAV trajectory are alternately ***,for the nonconvex UAV trajectory optimization problem,an approximate convex optimization problem is *** numerical results indicate that the scheme of this paper proposed is guaranteed to converge and also significantly reduces the entire power consumption of all UAVs compared to the benchmark schemes.

关键词： Energy consumption Multi-access edge computing Costs Power demand Autonomous aerial vehicles Iterative algorithms Convex functions

Synthesis of a High-Efficiency Demulsifier and Study on Optimal Demulsification Conditions

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China Petroleum Processing & Petrochemical Technology 2024年第1期26卷 107-115页

作者： Zhu Shuai Zhang YingYu Gui xia College of Chemical Engineering Nanjing Tech University30 Puzhunan RoadNanjing 211816China

Oil and water separation has always been a top priority in the oil *** this study,a series of hyperbranched fluorinated polyamine-amine polymers(HFPA1-5)were synthesized directly using an improved“one-pot method.”The highly active fluorinated p-trifluoromethylaniline was used as the core raw material,while diethylenetriamine and methyl acrylate were used as the chain segment.A hyperbranched fluorine-containing polyamine-amine demulsifier(NHFPA6)was obtained through nano-grafting copolymerization of *** enhance the demulsification and dehydration performance,the copolymerized HFPA6 was modified and ***,the effects of the combination ratio,demulsifier concentration,demulsification time,and demulsification temperature on the demulsification effect were *** results revealed that a combination ratio of DE-401:NHFPA6=1:1,a demulsification temperature of 50℃,a demulsification time of 60 min,and a demulsifier concentration of 150 mg/L yielded a dehydration rate as high as 99.80%.A response surface optimization design of demulsification conditions was *** model verified that the optimal demulsification conditions were 50℃,300 mg/L,and 90 ***,considering the economic benefits of factories,it is more favorable to select demulsification conditions with a shorter time and lower concentration when the dehydration standard is ***,the demulsification conditions were selected as 50℃,150 mg/L,and 60 *** to existing demulsifiers,the demulsifier developed in this study exhibits a lower demulsification temperature and higher demulsification efficiency.

关键词： hyperbranched fluorinated polyamine-amine nano-SiO_(2)