检索结果-南通市图书馆

Performance of double-arch tunnels under internal BLEVE

在线全文

学校读者我要写书评

暂无评论

Underground space 2024年第6期19卷 6-25页

作者： Ruishan cheng wensu Chen Hong Hao Center for Infrastructural Monitoring and Protection School of Civil and Mechanical EngineeringCurtin UniversityPerth 6000Australia Earthquake Engineering Research&Test Center Guangzhou UniversityGuangzhou 510000China

Double-arch tunnels,as one of the popular forms of tunnels,might be exposed to boiling liquid expanding vapour explosions(BLEVEs)associated with transported liquified petroleum gas(LPg),which could cause damage to the tunnel and even catastrophic collapse of the tunnel in extreme ***,very limited study has investigated the performance of double-arch tunnels when exposed to internal BLEVEs and in most analyses of tunnel responses to accidental *** TNT-equivalence method was used to approximate the explosion load,which may lead to inaccurate tunnel response *** study numerically investigates the response of typical double-arch tunnels to an internal BLEVE resulting from the instantaneous rupture of a 20 m^(3) LPg *** of various factors,including in-situ stresses,BLEVE locations,and lining configurations on tunnel responses are *** results show that the double-arch tunnels at their early-operation ages are more vulnerable to severe damage when exposed to the BLEVE due to the low action of in-situ stress of rock mass on the response of early-age *** is also found that directing the LPg tank to different driving lanes inside tunnels can affect the BLEVE-induced tunnel response more significantly than varying the configurations of tunnel ***,installing section-steel arches in the mid-wall can effectively improve the blast resistance of the double-arch tunnels against the internal *** addition,the prediction models based on multi-variate nonlinear regressions and machine learning methods are developed to predict the BLEVE-induced damage levels of the double-arch tunnels without and with section-steel arches.

关键词： Double-arch tunnel BLEVE Lining configuration section-steel arch Damage prediction

The higher-order topological pumping explored in the 2D acoustic crystal

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 127-133页

作者： Yanqiu wang Bin Liang Jianchun cheng Key Laboratory of Modern Acoustics Ministry of EducationInstitute of AcousticsDepartment of PhysicsNanjing UniversityNanjing 210093China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China

The topological pumping has been instrumental in advancing our understanding of topological phase transitions in various physical systems,which can be extended to uncover intriguing higher-order topological phases in the lower-dimensional ***,we propose a theoretical exploration of topological dipole pumping on an acoustic square superlattice by cyclically modulating intracell couplings,which shares the topological nature of an extended three-dimensional system with chiral hinge *** the multipole chiral numbers,we characterize the higher-order topological phases that arise during the *** evolution of topological phase transitions is verified by numerical simulations and shows corner states are transferred across the *** findings can inspire the construction of chiral hinge states in artificial crystals,opening up new possibilities for the design of devices allowing the unidirectional propagation of sound.

关键词： topological phases of matter Thouless pumping acoustic metamaterial

Machine learning and numerical investigation on drag coefficient of arbitrary polygonal particles

在线全文

学校读者我要写书评

暂无评论

International Journal of Mechanical system Dynamics 2024年第3期4卷 317-330页

作者： Haonan Xiang cheng cheng Pei Zhang genghui Jiang school of Energy and Power Engineering Nanjing University of Science and TechnologyNanjingChina school of Engineering Westlake UniversityHangzhouChina

The drag coefficient,as the most important parameter that characterizes particle dynamics in flows,has been the focus of a large number of *** good predictability is achieved for simple shapes,it is still challenging to accurately predict drag coefficient of complex-shaped particles even under moderate Reynolds number(Re).The problem is that the small-scale shape details of particles can still have considerable impact on the drag coefficient,but these geometrical details cannot be described by single shape *** address this challenge,we leverage modern deep-learning method's ability for pattern recognition,take multiple shape factors as input to better characterize particle-shape details,and use the drag coefficient as *** obtain a high-precision data set,the discrete element method coupled with an improved velocity interpolation scheme of the lattice Boltzmann method is used to simulate and analyze the sedimentation dynamics of polygonal *** different machine-learning models for predicting the drag coefficient are developed and *** results show that our model can well predict the drag coefficient with an average error of less than 5%for *** findings suggest that data-driven models can be an attractive option for the drag-coefficient prediction for particles with complex shapes.

关键词： drag coefficient arbitrary polygonal particle shape factor DEM–LBM machine Learning

Market Equilibrium Based on Cloud-edge Collaboration

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CsEE Journal of Power and Energy systems 2024年第1期10卷 96-104页

作者： Tong cheng Haiwang Zhong Qing Xia the state Key Laboratory of Power systems the Department of Electrical EngineeringTsinghua UniversityBeijing 100084China

Market participants can only bid with lagged information disclosure under the existing market mechanism,which can lead to information asymmetry and irrational market behavior,thus influencing market *** promote rational bidding behavior of market participants and improve market efficiency,a novel electricity market mechanism based on cloudedge collaboration is proposed in this *** market information,called residual demand curve,is published to market participants in real-time on the cloud side,while participants on the edge side are allowed to adjust their bids according to the information disclosure prior to closure *** proposed mechanism can encourage rational bids in an incentive-compatible way through the process of dynamic equilibrium while protecting participants’*** paper further formulates the mathematical model of market equilibrium to simulate the process of each market participant’s strategic bidding behavior towards equilibrium.A case study based on the IEEE 30-bus system shows the proposed market mechanism can effectively guide bidding behavior of market participants,while condensing exchanged information and protecting privacy of participants.

关键词： Cloud-edge collaboration market mechanism residual demand curve strategic bidding

Room-temperature ferrimagnetism and size-modulated electronic structures in two-dimensional cluster-based metal-organic frameworks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

science China Chemistry 2024年第4期67卷 1334-1340页

作者： Jing cheng Xingxing Li Jinlong Yang Key Laboratory of Precision and Intelligent Chemistry University of Science and Technology of ChinaHefei 230026China Department of Chemical Physics University of Science and Technology of ChinaHefei 230026China Hefei National Research Center for Physical sciences at the Microscale University of Science and Technology of ChinaHefei 230026China Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China

Cluster-assembled materials have attracted particular attention for their complex hierarchical structures and unique ***,the majority of cluster-based assemblies developed so far are either non-magnetic or only exhibit magnetic ordering with a relatively low Curie temperature,limiting their applications in ***,two-dimensional(2D)cluster-assembled materials with room-temperature magnetism remain highly *** this purpose,based on first principles calculations,we design a series of thermodynamically stable 2D cluster-based metal-organic frameworks(MOFs)Fe_(n)-(pyz)(n=1-6)by utilizing Fenmetal clusters as nodes and nitrogen-containing pyrazine ligands as organic *** 2D cluster-based MOFs exhibit robust ferrimagnetic ordering due to the strong d-p direct exchange interaction between d-electron spin of Fe_(n)(n=1-6)clusters and charge transfer-induced p-electron spin of pyrazine *** particular,the ferrimagnetic Curie temperatures are well above room temperature(up to 836 K).Additionally,altering the size of Fe_(n)clusters in Fe_(n)-(pyz)(n=1-6)MOFs results in diverse functional spintronic properties,including bipolar magnetic semiconductors,half semiconductors and Dirac half ***,these 2D assembled MOFs possess sizable magnetic anisotropy energies,up to 9.16 me V per formula.

关键词： metal-organic framework two-dimensional material half metal bipolar magnetic semiconductor magnet

“Capture-activation-recapture” mechanism-guided design of double-atom catalysts for electrocatalytic nitrogen reduction

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第9期96卷 437-447页

作者： cheng He shiqi Yan wenxue Zhang state Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi’an Jiaotong UniversityXi’an 710049ShaanxiChina school of Materials science and Engineering Chang’an UniversityXi’an 710064ShaanxiChina

Compared with the traditional industrial nitrogen fixation, electrocatalytic methods, especially those utilizing double-atom catalysts containing nonmetals, can give good consideration to the economy and environmental protection. However, the existing “acceptance-donation” mechanism is only applicable to bimetallic catalysts and nonmetallic double-atom catalysts containing boron atoms. Herein, a novel “capture-activation-recapture” mechanism for metal-nonmetal double-atom catalyst is proposed to solve the problem by adjusting the coordination environments of nonmetallic atoms and utilizing the activation effect of metal atoms on nitrogen. Based on this mechanism, the nitrogen reduction reaction (NRR) activity of 48 structures is calculated by density functional theory calculation, and four candidates are selected as outstanding electrocatalytic nitrogen reduction catalysts: si-Fe@Ng (U_(L) = –0.14 V), si-Co@Ng (U_(L)= –0.15 V), si-Mo@BP1 (U_(L) = 0 V), and si-Re@BP1 (U_(L) = –0.02 V). The analyses of electronic properties further confirm “capture-activation-recapture” mechanism and suggest that the difference in valence electron distribution between metal and si atoms triggers the activation of N≡N bonds. In addition, a machine learning approach is utilized to generate an expression and an intrinsic descriptor that considers the coordination environment to predict the limiting potential. This study offers profound insight into the synergistic mechanism of TM and si for NRR and guidance in the design of novel double-atom nitrogen fixation catalysts.

关键词： "Capture-activation-recapture"mechanism Double-atom catalyst Nitrogen reduction reaction Density functional theory

Model-driven path planning for robotic plasma cutting of branch pipe with single Y-groove based on pipe-rotating scheme

在线全文

学校读者我要写书评

暂无评论

Advances in Manufacturing 2024年第1期12卷 94-107页

作者： Yan Liu Qiu Tang Xin-cheng Tian school of Control science and Engineering Shandong UniversityJinan250061People’s Republic of China Engineering Research Center of Intelligent Unmanned system Ministry of EducationJinan250061People’s Republic of China school of Mechanical and Electronic Engineering Shandong Jianzhu UniversityJinan250101People’s Republic of China

The automatic cutting of intersecting pipes is a challenging task in *** improved automation and accuracy,this paper proposes a model-driven path planning approach for the robotic plasma cutting of a branch pipe with a single ***,it summarizes the intersection forms and introduces a dual-pipe intersection *** on this model,the moving three-plane structure(a description unit of the geometric characteristics of the intersecting curve)is constructed,and a geometric model of the branch pipe with a single Y-groove is ***,a novel mathematical model for plasma radius and taper compensation is ***,the compensation model and groove model are integrated by establishing movable ***,to prevent collisions between the plasma torch and workpiece,the torch height is planned and a branch pipe-rotating scheme is *** the established models and moving frames,the planned path description of cutting robot is provided in this novel *** accuracy of the proposed method is verified by simulations and robotic cutting experiments.

关键词： Automatic groove cutting of intersecting pipes Model-driven robot path planning Plasma beam radius and taper compensation

Open-shell Oligomers and Polymers: Theory, Characterization Methods, Molecular Design, and Applications

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer science 2024年第4期42卷 417-436页

作者： Xue-Qing wang cheng song Ting Lei Key Laboratory of Polymer Chemistry and Physics(Ministry of Education) School of Materials Science and EngineeringPeking UniversityBeijing100871China

Open-shell oligomers and polymers have exhibited intriguing electronic and magnetic properties, making them highly desirable for a wide range of applications, including ambipolar organic field-effect transistors (OFETs), photodetectors, organic thermoelectrics, and spintronics. Although open-shell ground states have been observed in certain small molecules and doped organic semiconductors, the exploration of open-shell ground-state conjugated polymers is still limited, and the strategies for designing these polymers remain obscure. This review aims to briefly introduce the theory and characterization methods of open-shell conjugated polymers, along with an overview of recent progress and applications. The objective is to stimulate further advancements and investigations in this promising area by shedding light on the potential of open-shell conjugated polymers and the challenges that lie ahead.

关键词： Conjugated polymers Open-shell molecules High-spin ground state Donor-acceptor(D-A)polymers Optoelectronic and magnetic properties

Designing novel adaptive dynamic event-triggered protocols for uncertain multi-agent systems

在线全文

学校读者我要写书评

暂无评论

science China(Information sciences) 2024年第1期67卷 310-311页

作者： Bin cheng Bin HE College of Electronics and Information Engineering Tongji University Frontiers science Center for Intelligent Autonomous systems

Multi-agent systems (MAss) have garnered widespread attention and have been investigated by numerous researchers in recent years, primarily due to their broad applications in industry, transportation, agriculture, and astronomy. while studying the cooperative control of MAss, numerous researchers place emphasis on reducing the frequency of communication among neighboring agents.

关键词： Directed graphs