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Aφ6-m Tunnel Boring Machine Steel Arch Splicing Manipulator

Chinese Journal of Mechanical Engineering 2022年第2期35卷 121-134页

作者： yuanfu he Yimin Xia Zhen Xu Jie Yao Bo Ning Xuemeng Xiao College of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China State Key Laboratory of High Performance Complex Manufacturing Central South UniversityChangsha 410083China China Railway Construction heavy Industry Co.Ltd. Changsha 410100China China Railway Siyuan Survey and Design Group Co.Ltd. Wuhan 430063China National-Local Joint Engineering Research Center of Underwater Tunnelling Technology Wuhan 430063China

Robotic splicing of steel arches is a challenging task that is necessary to realize the grasping and docking of steel arches in a limited space.Steel arches often have a mass of more than 200 kg and length of more than 4 m.Owing to the large volume and mass of steel arches and the high requirements for accurately positioning the splicing,it is difficult for a general manipulator to meet the stiffness requirements.To enhance the structural stiffness of the steel arch splicing manipulator,a single-degree-of-freedom(DOF)closed-loop mechanism was added to the grasping structure of the manipulator.Based on the basic principle of structural synthesis,a solution model of the single-DOF closed-loop mechanism was developed,and alternative kinematic pairs of the mechanism with different input constraints and output requirements were derived.Based on this model,a design method for a single-DOF closed-loop grasping mechanism and a posture adjustment mechanism for a steel arch was devised.Combined with the same dimensional subspace equivalence principle of the graphical-type synthesis method,12 types of steel arch splicing manipulator were constructed.By analyzing the motion/force transmission and structural complexity of the steel arch splicing manipulators,the best scheme was selected.A prototype of the steel arch splicing manipulator was manufactured.Adams software was used to obtain clearly the output trajectory of the end of the manipulator.The relative spatial positions of the upper and lower jaws under different working stages were analyzed,demonstrating that the manipulator satisfied the grasping requirements.Through a steel arch splicing experiment,the grasping effect,docking accuracy,and splicing efficiency of the manipulator met the design requirements.The steel arch splicing manipulator can replace the manual completion of the steel arch splicing operation,significantly improving the operation efficiency.

关键词： Steel arch splicing manipulator Single-DOF closed-loop mechanism Screw theory Graphical-type synthesis method Mechanism design

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Fear and delay effects on a food chain system with two kinds of different functional responses

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International Journal of Biomathematics 2024年第3期17卷 89-122页

作者： yuanfu Shao College of Science Guilin University of Technology GuilinGuangci 541004P.R.China

For food chain system with three populations,direct predation is the basic interaction between species.Different species often have different predation functional responses,so a food chain system with Holling-II response for middle predator and Beddinton-DeAngelis response for top predator is proposed.Apart from direct predation,predator population can significantly impact the survival of prey population by inducing the prey's fear,but the impact often possesses a time delay.This paper is concentrated to explore how the fear and time delay affect the system stability and the species persistence.By use of Lyapunov functional method and bifurcation theory,the positiveness and boundedness of solutions,local and global behavior of species,the system stability around the equilibrium states and various kinds of bifurcation are investigated.Numerically,some simulations are carried out to validate the main findings and the critical values of the bifurcation parameters of fear and conversion rate are obtained.It is observed that fear and delay can not only stabilize,but also destabilize the system,which depends on the magnitude of the fear and delay.The system varies from unstable to stable due to the continuous increase of the prey's fear by middle predator.Small fear induced by top predator or small delay of the prey's fear can stabilize the system,while they are sufficiently large,the system stability is to be destroyed.Simultaneously,the conversion rate can also change the stability and even make the species to be extinct.Some rich dynamics like multiple stabilities and various types of bistability behaviors are also exhibited,which results in the convergence of the species from one stable equilibrium to another.

关键词： Fear functional response equilibrium bifurcation analysis bi-stability

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Coral records of Mid-Holocene sea-level highstands and climate responses in the northern South China Sea

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Acta Oceanologica Sinica 2024年第2期43卷 43-57页

作者： yuanfu Yue Lichao Tang Kefu Yu Rongyong Huang School of Marine Sciences Coral Reef Research Center of ChinaGuangxi UniversityNanning 530004China Guangxi Laboratory on the Study of Coral Reefs in the South China Sea Nanning 530004China

High-resolution sea-level data and high-precision dating of corals in the northern South China Sea(SCS)during the Holocene provide a reference and historical background for current and future sea-level changes and a basis for scientific assessment of the evolutionary trend of coral reefs in the SCS.Although sporadic studies have been performed around Hainan Island in the northern SCS,the reconstructed sea level presents different values or is controversial because the indicative meaning of the sea-level indicators were neither quantified nor uniform criteria.here,we determined the quantitative relationship between modern living coral and sea level by measuring the top surfaces of 27 live Porites corals from the inner reef flat along the east coast of Hainan Island and assessed the accuracy of results obtained using coral as sea-level indicators.Additionally,three in situ fossil Porites corals were analyzed based on elevation measurements,digital X-ray radiography,and U-Th dating.The survey results showed that the indicative meanings for the modern live Porites corals is(146.09±8.35)cm below the mean tide level(MTL).It suggested that their upward growth limit is constrained by the sea level,and the lowest low water is the highest level of survival for the modern live Porites corals.Based on the newly defined indicative meanings,6 new sea-level index points(SLIPs)were obtained and 19 published SLIPs were recalculated.Those SLIPs indicated a relative sea level fluctuation between(227.7±9.8)cm to(154.88±9.8)cm MTL between(5393±25)cal a BP and(3390±12)cal a BP,providing evidences of the Mid-Holocene sea-level highstand in the northern SCS.Besides that,our analysis demonstrated that different sea-level histories may be produced based on different indicative meanings or criteria.The dataset of 276 coral U-Th ages indicates that coral reef development in the northern SCS comprised the initial development,boom growth,decline,and flourishing development again.A comparison with regional records indicated that synergistic ef

关键词： northern South China Sea Middle Holocene sea-level highstand Porites corals climate response

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Fe-N_(x) sites coupled with core-shell FeS@C nanoparticles to boost the oxygen catalysis for rechargeable Zn-air batteries

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Journal of Energy Chemistry 2024年第3期90卷 565-577,I0013页

作者： Katam Srinivas Zhuo Chen Anran Chen Fei Ma Ming-qiang Zhu yuanfu Chen School of Integrated Circuit Science and Engineering and State Key Laboratory of Electronic Thin Films and Integrated DevicesUniversity of Electronic Science and Technology of ChinaChengdu 610054SichuanChina College of Mechanical and Electronic Engineering Northwest A&F UniversityYangling 712100ShaanxiChina School of Materials and Energy Yunnan UniversityKunming 650091YunnanChina

The development of efficient single-atom catalysts(SACs) for the oxygen reduction reaction(ORR)remains a formidable challenge,primarily due to the symmetric charge distribution of metal singleatom sites(M-N_(4)).To address such issue,herein,Fe-N_(x) sites coupled synergistic catalysts fabrication strategy is presented to break the uniform electronic distribution,thus enhancing the intrinsic catalytic activity.Precisely,atomically dispersed Fe-N_(x) sites supported on N/S-doped mesoporous carbon(NSC)coupled with FeS@C core-shell nanoparticles(FAS-NSC@950) is synthesized by a facile hydrothermal reaction and subsequent pyrolysis.Due to the presence of an in situ-grown conductive graphitic layer(shell),the FeS nanoparticles(core) effectively adjust the electronic structure of single-atom Fe sites and facilitate the ORR kinetics via short/long-range coupling interactions.Consequently,FAS-NSC@950displays a more positive half-wave potential(E_(1/2)) of 0.871 V with a significantly boosted ORR kinetics(Tafel slope=52.2 mV dec^(-1)),outpacing the commercial Pt/C(E_(1/2)=0.84 V and Tafel slope=54.6 mV dec^(-1)).As a bifunctional electrocatalyst,it displays a smaller bifunctional activity parameter(ΔE) of 0.673 V,surpassing the Pt/C-RuO_(2) combination(ΔE=0.724 V).Besides,the FAS-NSC@950-based zincair battery(ZAB) displays superior power density,specific capacity,and long-term cycling performance to the Pt/C-Ir/C-based ZAB.This work significantly contributes to the field by offering a promising strategy to enhance the catalytic activity of SACs for ORR,with potential implications for energy conversion and storage technologies.

关键词： Fe-N_(x)sites Core-shell FeS@C Synergistic interactions Oxygen reduction reaction Zn-air battery

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钢拱架封口机构抓取模块传动性能分析及优化设计

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华南理工大学学报（自然科学版） 2022年第8期50卷 82-91页

作者：何源福夏毅敏李深远姚捷中南大学机电工程学院湖南长沙410083 中南大学高性能复杂制造国家重点实验室湖南长沙410083 中国铁建重工集团股份有限公司湖南长沙410100 中铁第四勘察设计院集团有限公司湖北武汉430063 水下隧道技术国家地方联合工程研究中心湖北武汉430063

目前隧道掘进机(TBM)施工过程的钢拱架安装均采用人工操作的形式完成,作业环境非常恶劣,导致钢拱架支护效率低、劳动强度大、施工风险高。为此,笔者及其所在团队前期设计了一种钢拱架快速封口安装机构,用于代替人工完成钢拱架的封口作... 详细信息

目前隧道掘进机(TBM)施工过程的钢拱架安装均采用人工操作的形式完成,作业环境非常恶劣,导致钢拱架支护效率低、劳动强度大、施工风险高。为此,笔者及其所在团队前期设计了一种钢拱架快速封口安装机构,用于代替人工完成钢拱架的封口作业。抓取模块作为该封口安装机构中直接与钢拱架接触的核心部件,需要具有足够的传动性能,以满足夹持作业需求。为此,文中基于螺旋理论,建立了其运动学模型,推导了输入旋量和输出旋量之间的虚拟系数,研究得到了抓取模块的传动性能,并提出了相应的传动指标;在此基础上,建立了抓取模块的尺寸参数优化模型,结合钢拱架封口件的实际抓取需求,得到抓取模块各尺寸参数的优化结果如下:卡爪与连杆的初始夹角α=88°、导杆的初始位置l_(FJ)=170 mm,导杆运动范围0~63 mm。利用ADAMS软件对抓取模块从夹持到张开的姿势变化过程进行分析,得到以下结论:卡爪末端间的距离从50.0mm逐渐增加至234.6mm,满足抓取空间需求;输出扭矩呈先增大后减小的趋势,卡爪完全张开时扭矩最小值为21.23N·m,满足输出扭矩需求。钢拱架封口成环的样机实验表明:抓取模块尺寸参数的测量值与计算模型仅相差4.5mm,说明模型是正确的;钢拱架的整个封口安装时间为8.6min,与传统人工作业相比,钢拱架封口机构的作业效率提高了20%~70%。

关键词：钢拱架快速封口安装机构抓取模块螺旋理论传动性能尺寸参数优化

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NbN quantum dots anchored hollow carbon nanorods as efficient polysulfide immobilizer and lithium stabilizer for Li-S full batteries

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Journal of Energy Chemistry 2024年第1期88卷 260-271,I0007页

作者： Fei Ma Zhuo Chen Katam Srinivas Ziheng Zhang Yu Wu Dawei Liu hesheng Yu Yue Wang Xinsheng Li Ming-qiang Zhu Qi Wu yuanfu Chen School of Integrated Circuit Science and Engineering and State Key Laboratory of Electronic Thin Films and Integrated DevicesUniversity of Electronic Science and TechnologyChengdu 610054SichuanChina College of Science and Institute of Oxygen Supply Center of Tibetan Studies(Everest Research Institute)Tibet UniversityLhasa 850000TibetChina College of Mechanical and Electronic Engineering Northwest A&F UniversityXianyang 712100ShaanxiChina

The shuttle effect of lithium polysulfides(LiPSs)and uncontrollable lithium dendrite growth seriously hinder the practical application of lithium-sulfur(Li-S)batteries.To simultaneously address such issues,monodispersed Nb N quantum dots anchored on nitrogen-doped hollow carbon nanorods(NbN@NHCR)are elaborately developed as efficient Li PSs immobilizer and Li stabilizer for high-performance Li-S full batteries.Density functional theory(DFT)calculations and experimental characterizations demonstrate that the sulfiphilic and lithiophilic NbN@NHCR hybrid can not only efficiently immobilize the soluble Li PSs and facilitate diffusion-conversion kinetics for alleviating the shuttling effect,but also homogenize the distribution of Li+ions and regulate uniform Li deposition for suppressing Li-dendrite growth.As a result,the assembled Li-S full batteries(NbN@NHCR-S||Nb N@NHCR-Li)deliver excellent long-term cycling stability with a low decay rate of 0.031%per cycle over 1000 cycles at high rate of 2 C.Even at a high S loading of 5.8 mg cm^(-2)and a low electrolyte/sulfur ratio of 5.2μL mg^(-1),a large areal capacity of 6.2 mA h cm^(-2)can be achieved in Li-S pouch cell at 0.1 C.This study provides a new perspective via designing a dual-functional sulfiphilic and lithiophilic hybrid to address serious issues of the shuttle effect of S cathode and dendrite growth of Li anode.

关键词： Dual-functional host NbN quantum dots Shuttle effect Dendrite-free Li anode Li-S full batteries

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考虑混凝土凝结作用的衬砌台车动态特性析

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建筑结构 2023年第S1期53卷 1803-1807页

作者：杨侠曹殿彬高瑛凯何源福济南轨道交通集团有限公司济南250014 中铁十四局集团隧道工程有限公司济南250014 中南大学机电工程学院长沙410083

为了提高衬砌台车在混凝土振捣施工过程中的可靠性,对衬砌台车施工过程的振动特性展开研究。建立衬砌台车的受载模型,结合混凝土凝结作用的影响,分析不同浇筑高度下的衬砌台车最大应力;在得到预应力状态的基础上,利用模态分析研究不同... 详细信息

为了提高衬砌台车在混凝土振捣施工过程中的可靠性,对衬砌台车施工过程的振动特性展开研究。建立衬砌台车的受载模型,结合混凝土凝结作用的影响,分析不同浇筑高度下的衬砌台车最大应力;在得到预应力状态的基础上,利用模态分析研究不同浇筑高度下衬砌台车的前6阶固有频率和振型,并探究模板厚度对不同浇筑阶段衬砌台车的振动特性的影响。结果表明:衬砌台车前6阶模态固有频率集中在18Hz~55Hz之间,随着混凝土浇筑高度的增加,各阶固有频率逐渐增加。浇筑高度2m的衬砌台车前3阶模态振型主要以横向变形为主,第4~6接模态振型横向变形的基础上,增加了轴向的弯曲变形;随着浇筑高度的增加,衬砌台车的轴向弯曲变形逐渐减少,到浇筑高度8m时,前6阶模态振型基本以横向变形为主了。随着模板厚度的增加,衬砌台车前3节模态固有频率呈线性减少,模板厚度从12mm增加到20mm时,前3阶模态固有频率大致都减少了1.5Hz。

关键词：混凝土凝结衬砌台车预应力模态分析振动特性模板厚度

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Nickel-catalyzed arylcyanation of alkenes via cyano group translocation: access to 1,n-dinitriles or 4-amino nitriles

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Science China Chemistry 2024年

作者： Xiaohong Li Shenfan Wang Xiangxiang Fu Donghui Xing Zeyuan Fu yuanfu Deng Huanfeng Jiang Liangbin Huang State Key Laboratory of Pulp and Paper Engineering School of Chemistry and Chemical Engineering South China University of Technology

herein, a nickel-catalyzed arylcyanation of unactivated alkenes via cyano group translocation with aryl boronic acids has been developed. These transformations provided a robust approach to constructing structurally diverse 1,n-dinitriles or 4-amino nitriles from easily prepared and commercially available starting materials. The cyano group translocation was achieved,involving the addition into the intramolecular C–N triple bond followed by the retro-Thorpe reaction. Mechanistic studies revealed that high temperature and CsHCO3as the base were crucial for the cyano group translocation.

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新世纪中国科幻电影的想象力建构和后工业美学

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上海文化 2024年第6期 102-110页

作者：鲍远福陈添兰贵州民族大学传媒学院贵州民族大学

中国科幻电影在近年来蓬勃发展,并逐渐形成了新颖的艺术风格和后工业美学特征。后工业美学建基于电影工业美学理论,按照“无中生有”的符号逻辑构建科幻电影的想象力话语系统。以《流浪地球》系列为代表的“中国式科幻电影”立足于“虚... 详细信息

中国科幻电影在近年来蓬勃发展,并逐渐形成了新颖的艺术风格和后工业美学特征。后工业美学建基于电影工业美学理论,按照“无中生有”的符号逻辑构建科幻电影的想象力话语系统。以《流浪地球》系列为代表的“中国式科幻电影”立足于“虚拟拍摄”和“数字智造”等后工业生产手段,构建了一种融合了本土价值观系统和全球化视野的“数绘图像”表意系统。中国科幻电影的后工业美学转型,不仅通过电影艺术的形式构建了新时代的中国形象,也为我们反思“中国式现代化”进程中科技变革与人文想象的关系、创新当代电影美学话语范式提供了难得的艺术资源。

关键词：中国科幻电影想象力建构后工业美学中国形象

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Recent advances in Fe-N-C single-atom site coupled synergistic catalysts for boosting oxygen reduction reaction

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Electron 2024年第1期2卷 1-38页

作者： Katam Srinivas Jian Zhen hesheng Yu Dawei Liu Jian Zhen Ou Ming‐qiang Zhu yuanfu Chen School of Integrated Circuit Science and Engineering and State Key Laboratory of Electronic Thin Films and Integrated DevicesUniversity of Electronic Science and Technology of ChinaChengduSichuanChina College of Mechanical and Electronic Engineering Northwest A&F UniversityYanglingChina School of Engineering RMIT UniversityMelbourneVictoriaAustralia

Metal-air batteries,fuel cells,and electrochemical H_(2)O2 production currently attract substantial consideration in the energy sector owing to their efficiency and eco-consciousness.However,their broader use is hindered by the complex oxygen reduction reaction(ORR)that occurs at cathodes and involves intricate electron transfers.Despite the significant ORR performance of platinum-based catalysts,their high cost,operational limitations,and susceptibility to methanol poisoning hinder broader implementation.This emphasizes the need for efficient nonprecious metal-based ORR electrocatalysts.A promising approach involves utilizing single-atom catalysts(SACs)featuring metal-nitrogen-carbon(M-N-C)coordination sites.SACs offer advantages such as optimal utilization of metal atoms,uniform active centers,precisely defined catalytic sites,and robust metal-support interactions.However,the symmetrical electron distribution around the central metal atom of a single-atom site(M-N4)often results in suboptimal ORR performance.This challenge can be addressed by carefully tailoring the surrounding environment of the active center.This review specifically focuses on recent advancements in the Fe-N4 environment within Fe-N-C SACs.It highlights the promising strategy of coupling Fe-N4 sites with metal clusters and/or nanoparticles,which enhances intrinsic activity.By capitalizing on the interplay between Fe-N4 sites and associated species,overall ORR performance improved.The review combines findings from experimental studies and density functional theory simulations,covering synthesis strategies for Fe-N-C coupled synergistic catalysts,characterization techniques,and the influence of associated particles on ORR activity.By offering a comprehensive outlook,the review aims to encourage research into high-efficiency Fe single-atom sites coupled synergistic catalysts for real-world applications in the coming years.

关键词： electrocatalysis oxygen reduction reaction particle@Fe-N-C single-atom catalysts synergistic catalysts

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