期刊文献+
共找到2,713篇文章
< 1 2 136 >
每页显示 20 50 100
Seismic design and performance of building structures with self-centering steel-concrete hybrid single-pier coupled walls
1
作者 Mojtaba Farahi Fabio Freddi Massimo Latour 《Resilient Cities and Structures》 2026年第1期85-101,共17页
In response to the demand for seismic-resilient structures,various innovative solutions have emerged to reduce local damage and residual deformations,facilitating repair operations in the aftermath of high-intensity e... In response to the demand for seismic-resilient structures,various innovative solutions have emerged to reduce local damage and residual deformations,facilitating repair operations in the aftermath of high-intensity earth-quakes.This paper examines the seismic performance of a steel-concrete hybrid wall system equipped with a selfcentering solution to mitigate earthquake-induced residual deformations.The considered hybrid system includes a Reinforced Concrete(RC)shear wall with two steel side columns connected by coupling steel beams.In this study,a novel type of coupling beams featuring a friction-damped self-centering system is implemented.The system is referred to as Self-Centering Hybrid Single-Pier Coupled Wall(SC-SP-HCW)and aims to minimize damage and residual deformations after earthquakes,which in turn facilitates repairs and enhances seismic resilience.Unlike conventional self-centering coupling beams with post-tensioned tendons,the self-centering configuration in this system does not rely on a gap-opening mechanism at the wall-beam connection interface,eliminating frame expansion effects.The proposed self-centering devices can also be implemented as preassembled links,which facilitates installation and reduces uncertainties associated with the on-site posttensioning procedure.The seismic performance of SC-SP-HCWs is investigated through nonlinear static and incremental dynamic analyses on case study SC-SP-HCWs designed as the lateral load-resisting systems of an eight-story building.The seismic response of the case study SC-SP-HCWs is investigated,considering both local and global engineering demand parameters(EDPs).The results demonstrate the ability of the SC-SP-HCWs to significantly reduce earthquake-induced residual deformations without exacerbating damage to structural ele-ments typically observed in conventional coupled walls. 展开更多
关键词 Hybrid coupled walls Damage-free self-centering links Friction devices Seismic performance Reinforced concrete walls
在线阅读 下载PDF
Long term efficacy and stability of corneal collagen cross linking for post-LASIK ectasia: an average of 80mo follow-up 被引量:1
2
作者 Walid Sharif Zaid Rushdi Ali Khaled Sharif 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2019年第2期333-337,共5页
This study was designed to evaluate efficacy and stability of corneal collagen crosslinking(CXL) in halting the progression of post-laser in situ keratomileusis(LASIK) ectasia and provide long-term follow-up results w... This study was designed to evaluate efficacy and stability of corneal collagen crosslinking(CXL) in halting the progression of post-laser in situ keratomileusis(LASIK) ectasia and provide long-term follow-up results with an average of 80 mo. Patients with post-LASIK ectasia were treated with CXL between December 2007 and January 2012. Main outcome measures were uncorrected distance visual acuities(UDVA) and corrected distance visual acuities(CDVA), minimum and maximum keratometry(K) values, spherical and cylindrical refraction, and corneal thickness. The study evaluated 17 eyes for 13 patients(8 men, 5 women) with mean age of 31y(range 23 to 39) and mean follow-up of 80.7±15(range 57 to 102)mo. UDVA and CDVA improved from logMAR 0.53±0.36(20/63) to 0.49±0.4(20/50)(P=0.43) and from 0.18±0.17(20/28) to 0.16±0.16(20/27)(P=0.55) respectively. In 15 eyes UDVA and in 13 eyes CDVA either remained stable or improved ≥1 Snellen lines(88.2%) and(76.5%) respectively. Although statistically insignificant, spherical and cylindrical refraction decreased post-CXL from-1.26±2.87 to-0.38±2.32 diopters(D)(P=0.054) and from-3.80±2.47 to-3.04±2.18 D(P=0.13) respectively. Kmax significantly decreased from 44.23±3.76 to 42.85±3.08 D(P=0.013) and Kmin decreased from 41.07±3.61 to 40.00±2.65 D(P=0.057). Corneal thickness decreased from 470±42 to 460±41 μm, but was statistically non-significant(P=0.063). Therefore, CXL is effective in halting and partially reversing the progression of postLASIK ectasia on the long-term(mean follow-up of more than 80mo), thus highlighting the stability and maintained effect of CXL for such cases. 展开更多
关键词 post-LASIK ECTASIA post-LASIK ECTASIA CORNEAL COLLAGEN cross linking
原文传递
Color Image Segmentation by Edge Linking and Region Grouping
3
作者 王宁 杨杰 《Journal of Shanghai Jiaotong university(Science)》 EI 2011年第4期412-419,共8页
A novel method toward color image segmentation is proposed based on edge linking and region grouping. Firstly,the edges extracted by the Canny detector are linked to form regions.Each of the end points of edges is con... A novel method toward color image segmentation is proposed based on edge linking and region grouping. Firstly,the edges extracted by the Canny detector are linked to form regions.Each of the end points of edges is connected by a direct line to the nearest pixel on another edge segment within a sub-window.A new distance is defined based on the feature that the edge tends to preserve its original direction.By sampling the lines to the image,the image is over-segmented to labeled regions.Secondly,the labeled regions are grouped both locally and globally.A decision tree is constructed to decide the importance of properties that affect the merging procedure.Finally,the result is refined by user’s selection of regions that compose the desired object. Experiments show that the method can effectively segment the object and is much faster than the state-of-the-art color image segmentation methods. 展开更多
关键词 color image segmentation edge linking region grouping
原文传递
Linking Words in English
4
作者 许崇玲 《疯狂英语(双语世界)》 2025年第3期25-29,37,共6页
Linking words,also called transition words,are quite useful in English expressions.Linking words are not the same as conjunctions,although some conjunctions can function as linking words.Here's a clear explanation... Linking words,also called transition words,are quite useful in English expressions.Linking words are not the same as conjunctions,although some conjunctions can function as linking words.Here's a clear explanation for English learners,followed by a wellorganized passage on the functions of linking words in writing and communication. 展开更多
关键词 functions linking words linking wordsalso CONJUNCTIONS english expressionslinking words transition wordsare linking words linking wordsheres transition words
在线阅读 下载PDF
Post-modification-induced supramolecular transformation of Hopf link to macrocycle
5
作者 Pan-Pan Hua Hui-Jun Feng +2 位作者 Shu-Ning Lan Francisco Aznarez Li-Fang Zhang 《Chinese Chemical Letters》 2025年第6期637-640,共4页
Although supramolecular transformations have been emerged as a potent strategy for transitioning between various topologies,post-modification induced topological transformations have never been explored in the context... Although supramolecular transformations have been emerged as a potent strategy for transitioning between various topologies,post-modification induced topological transformations have never been explored in the context of[2]catenane topologies.In this study,we present a novel supramolecular transformation between a Hopf link and a macrocycle,induced by the Diels–Alder click reaction.By strategically selecting the half-sandwich ruthenium binuclear fragment B as a rigid capping agent,we successfully integrated tetrazine moieties into the metalla[2]catenane structure.We demonstrated that the introduction of 2,5-norbornadiene(NBD)as an external stimulus allows for the transformation of the novel metalla[2]catenane,featuring reactive tetrazine sites,into the corresponding monomeric ring through postmodification for the first time.The synthetic results are corroborated by single-crystal X-ray diffraction analysis,ESI-TOF/MS,elemental analysis,and detailed solution-state NMR techniques. 展开更多
关键词 Diels–Alder reaction Half-sandwich ruthenium acceptor Hopf link Post-modification Supramolecular transformation
原文传递
ESG赋能高校环境专业教学探索——基于“双碳”背景下环境未来发展国际前沿课程的实践
6
作者 张晓媛 鲁金凤 刘雨 《高教学刊》 2026年第4期17-20,共4页
新工科教育理念的提出给环境专业改革带来新的挑战与契机,大类招生制度的实施则为跨学科融合和创新教学提供更广泛的空间。为提升环境专业的竞争力,该研究探讨如何有效将ESG内容融入环境专业教学。通过ESG融入的跨学科课程开发、AI赋能... 新工科教育理念的提出给环境专业改革带来新的挑战与契机,大类招生制度的实施则为跨学科融合和创新教学提供更广泛的空间。为提升环境专业的竞争力,该研究探讨如何有效将ESG内容融入环境专业教学。通过ESG融入的跨学科课程开发、AI赋能的项目式学习实践、跨学科合作、职业发展指导等创新教学方法,构建高校环境专业教学的LINK模式ESG应用策略,旨在增强学生在环境与可持续发展领域的职业竞争力。以“双碳”背景下环境未来发展国际前沿课程为例,详细探讨通过多元化教学资源、项目式学习与“开卷式”考核的方式,将ESG教学内容融入课程的过程和效果,为ESG赋能高校环境专业教学改革提供理论支持和实践参考。 展开更多
关键词 新工科教育 ESG赋能 跨学科融合 LINK模式 AI赋能
在线阅读 下载PDF
Renovating Beijing’s South Central Axis
7
作者 WANG YU 《China Today》 2026年第4期60-62,共3页
The South Central Axis in Beijing showcases China’s image and highlights its cultural confidence.THE Central Axis is the centerpiece of the Chinese capital’s urban spatial layout.The southern extended section of the... The South Central Axis in Beijing showcases China’s image and highlights its cultural confidence.THE Central Axis is the centerpiece of the Chinese capital’s urban spatial layout.The southern extended section of the Central Axis,or the South Central Axis,stretches from the Yongdingmen Gate Tower in the north to the South Fifth Ring Road in the south.While being a strategic transport link facilitating the coordinated development of the Beijing-Tianjin-Hebei region,it also showcases China’s vision for the future and highlights its cultural confidence. 展开更多
关键词 BEIJING central axis Cultural Confidence South Central Axis central axisor yongdingmen gate tower transport link Strategic Transport Link
在线阅读 下载PDF
Innovation and Practice Research on the Modern Apprenticeship Training Model for Nursing Talents Integrating General-Specialty Integration, Moral-Technical Fusion, and Specialty-Innovation Union
8
作者 Yuan Yuan Ling Shen Lei Yin 《Journal of Clinical and Nursing Research》 2026年第2期176-183,共8页
Modern apprenticeship emphasizes strengthening school-enterprise cooperation,deepening the integration of production and education,and promoting the combination of work and study to achieve seamless connection between... Modern apprenticeship emphasizes strengthening school-enterprise cooperation,deepening the integration of production and education,and promoting the combination of work and study to achieve seamless connection between professional education and industrial needs,thereby improving the quality of talent training.This paper analyzes the current problems in the nursing talent training system,elaborates on the significance of cultivating nursing talents based on modern apprenticeship,and proposes new ideas for constructing a modern apprenticeship training model for nursing talents from the perspectives of“integrating general and specialized education,merging virtue and skills,and linking specialization and innovation”.The aim is to further promote the organic combination of nursing talent training goals and post needs,for reference only. 展开更多
关键词 Integration of general and specialized education Merging of virtue and skills linking of specialization and innovation Nursing talent training Modern apprenticeship
在线阅读 下载PDF
A Hybrid Clique-Based Method with Structural Feature Node Extraction for Community Detection in Overlapping Networks
9
作者 Sicheng Ma Lixiang Zhang +3 位作者 Guocai Chen Zeyu Dai Junru Zhu Wei Fang 《Computers, Materials & Continua》 2026年第4期2231-2253,共23页
Community detection is a fundamental problem in network analysis for identifying densely connected node clusters,with successful applications in diverse fields like social networks,recommendation systems,biology,and c... Community detection is a fundamental problem in network analysis for identifying densely connected node clusters,with successful applications in diverse fields like social networks,recommendation systems,biology,and cyberattack detection.Overlapping community detection refers to the case of a node belonging to multiple communities simultaneously,which is a much more meaningful and challenging task.Graph representation learning with Evolutionary Computation has been studied well in overlapping community detection to deal with complex network structures and characteristics.However,most of them focus on searching the entire solution space,which can be inefficient and lead to inadequate results.To overcome the problem,a structural feature node extraction method is first proposed that can effectively map a network into a structural embedding space.Thus,nodes within the network are classified into hierarchical levels based on their structural feature strength,and only nodes with relatively high strength are considered in subsequent search steps to reduce the search space.Then,a maximal-clique representation method is employed on the given vertex set to identify overlapping nodes.A hybrid clique-based multi-objective evolutionary algorithmwith decomposition method is designed to address cliques and the remaining unexplored nodes separately.The number of communities generated with this allocation method is closer to the actual partition count with high division quality.Experimental results on nine usually used real-world networks,five synthetic networks,and two large-scale networks demonstrate the effectiveness of the proposed methodology in terms of community quality and algorithmic efficiency,compared to traditional,MOEA-based,and graph embedding-based community detection algorithms. 展开更多
关键词 Community detection graph embedding multi-objective evolutionary algorithm CLIQUES link strength
在线阅读 下载PDF
Optimizing RPL Routing Using Tabu Search to Improve Link Stability and Energy Consumption in IoT Networks
10
作者 Mehran Tarif Mohammadhossein Homaei +1 位作者 Abbas Mirzaei Babak Nouri-Moghaddam 《Computers, Materials & Continua》 2026年第4期2095-2126,共32页
The Routing Protocol for Low-power and Lossy Networks(RPL)is widely used in Internet of Things(IoT)systems,where devices usually have very limited resources.However,RPL still faces several problems,such as high energy... The Routing Protocol for Low-power and Lossy Networks(RPL)is widely used in Internet of Things(IoT)systems,where devices usually have very limited resources.However,RPL still faces several problems,such as high energy usage,unstable links,and inefficient routing decisions,which reduce the overall network performance and lifetime.In this work,we introduce TABURPL,an improved routing method that applies Tabu Search(TS)to optimize the parent selection process.The method uses a combined cost function that considers Residual Energy,Transmission Energy,Distance to the Sink,Hop Count,Expected Transmission Count(ETX),and Link Stability Rate(LSR).Simulation results show that TABURPL improves link stability,lowers energy consumption,and increases the packet delivery ratio compared with standard RPL and other existing approaches.These results indicate that Tabu Search can handle the complex trade-offs in IoT routing and can provide a more reliable solution for extending the network lifetime. 展开更多
关键词 Internet of things RPL protocol tabu search energy efficiency link stability multi-metric routing
在线阅读 下载PDF
Constructions of Control Sequence Set for Hierarchical Access in Data Link Network
11
作者 Niu Xianhua Ma Jiabei +3 位作者 Zhou Enzhi Wang Yaoxuan Zeng Bosen Li Zhiping 《China Communications》 2026年第1期67-80,共14页
As an important resource in data link,time slots should be strategically allocated to enhance transmission efficiency and resist eavesdropping,especially considering the tremendous increase in the number of nodes and ... As an important resource in data link,time slots should be strategically allocated to enhance transmission efficiency and resist eavesdropping,especially considering the tremendous increase in the number of nodes and diverse communication needs.It is crucial to design control sequences with robust randomness and conflict-freeness to properly address differentiated access control in data link.In this paper,we propose a hierarchical access control scheme based on control sequences to achieve high utilization of time slots and differentiated access control.A theoretical bound of the hierarchical control sequence set is derived to characterize the constraints on the parameters of the sequence set.Moreover,two classes of optimal hierarchical control sequence sets satisfying the theoretical bound are constructed,both of which enable the scheme to achieve maximum utilization of time slots.Compared with the fixed time slot allocation scheme,our scheme reduces the symbol error rate by up to 9%,which indicates a significant improvement in anti-interference and eavesdropping capabilities. 展开更多
关键词 control sequence data link hierarchical access control theoretical bound
在线阅读 下载PDF
Modbus TCP和PLC Link通信技术在航天产品测试设备中的应用
12
作者 邢化友 张晔 宋鹏涛 《自动化应用》 2026年第4期239-241,245,共4页
提出了基于以太网Modbus TCP和PLC Link通信技术的应用方案,利用台达PLC的PLC Link通信技术实现两台PLC之间实时数据的自动共享,以完成对大型网状天线驱动组件的功能和性能测试。主要测试其在不同负载下的输出力矩、驱动电压、驱动电流... 提出了基于以太网Modbus TCP和PLC Link通信技术的应用方案,利用台达PLC的PLC Link通信技术实现两台PLC之间实时数据的自动共享,以完成对大型网状天线驱动组件的功能和性能测试。主要测试其在不同负载下的输出力矩、驱动电压、驱动电流、电机转速和输出转速。磁粉制动器为系统提供负载,下位机主站PLC通过模拟量采集模块实时采集扭矩传感器的扭矩信号,并与磁粉制动器提供的负载形成PID闭环控制,实现负载的自动加载。下位机从站PLC负责程控电源的电压电流控制,利用输出端光电编码器实时采集输出转速。最终,通过LabVIEW平台开发的专用测试软件,结合Modbus TCP总线对下位机主从站PLC进行实时采集和控制,实现上位机与下位机主从站PLC之间的数据交互。通过在驱动组件产品热真空试验中的实际应用,证明了该通信技术的有效性。 展开更多
关键词 Modbus TCP PLC Link LabVIEW PID 扭矩传感器 磁粉制动器
在线阅读 下载PDF
Learning Time Embedding for Temporal Knowledge Graph Completion
13
作者 Jinglu Chen Mengpan Chen +2 位作者 Wenhao Zhang Huihui Ren Daniel Dajun Zeng 《Computers, Materials & Continua》 2026年第2期827-851,共25页
Temporal knowledge graph completion(TKGC),which merges temporal information into traditional static knowledge graph completion(SKGC),has garnered increasing attention recently.Among numerous emerging approaches,transl... Temporal knowledge graph completion(TKGC),which merges temporal information into traditional static knowledge graph completion(SKGC),has garnered increasing attention recently.Among numerous emerging approaches,translation-based embedding models constitute a prominent approach in TKGC research.However,existing translation-based methods typically incorporate timestamps into entities or relations,rather than utilizing them independently.This practice fails to fully exploit the rich semantics inherent in temporal information,thereby weakening the expressive capability of models.To address this limitation,we propose embedding timestamps,like entities and relations,in one or more dedicated semantic spaces.After projecting all embeddings into a shared space,we use the relation-timestamp pair instead of the conventional relation embedding as the translation vector between head and tail entities.Our method elevates timestamps to the same representational significance as entities and relations.Based on this strategy,we introduce two novel translation-based embedding models:TE-TransR and TE-TransT.With the independent representation of timestamps,our method not only enhances capabilities in link prediction but also facilitates a relatively underexplored task,namely time prediction.To further bolster the precision and reliability of time prediction,we introduce a granular,time unit-based timestamp setting and a relation-specific evaluation protocol.Extensive experiments demonstrate that our models achieve strong performance on link prediction benchmarks,with TE-TransR outperforming existing baselines in the time prediction task. 展开更多
关键词 Temporal knowledge graph(TKG) TKG embedding model link prediction time prediction
在线阅读 下载PDF
Cascading failure modeling and survivability analysis of weak-communication underwater unmanned swarm networks
14
作者 Yifan Yuan Xiaohong Shen +3 位作者 Lin Sun Ke He Yongsheng Yan Haiyan Wang 《Defence Technology(防务技术)》 2026年第2期66-82,共17页
Cascading failures pose a serious threat to the survivability of underwater unmanned swarm networks(UUSNs),significantly limiting their service ability in collaborative missions such as military reconnaissance and env... Cascading failures pose a serious threat to the survivability of underwater unmanned swarm networks(UUSNs),significantly limiting their service ability in collaborative missions such as military reconnaissance and environmental monitoring.Existing failure models primarily focus on power grids and traffic systems,and don't address the unique challenges of weak-communication UUSNs.In UUSNs,cascading failure present a complex and dynamic process driven by the coupling of unstable acoustic channels,passive node drift,adversarial attacks,and network heterogeneity.To address these challenges,a directed weighted graph model of UUSNs is first developed,in which node positions are updated according to ocean-current-driven drift and link weights reflect the probability of successful acoustic transmission.Building on this UUSNs graph model,a cascading failure model is proposed that integrates a normal-failure-recovery state-cycle mechanism,multiple attack strategies,and routingbased load redistribution.Finally,under a five-level connectivity UUSNs scheme,simulations are conducted to analyze how dynamic topology,network load,node recovery delay,and attack modes jointly affect network survivability.The main findings are:(1)moderate node drift can improve survivability by activating weak links;(2)based-energy routing(BER)outperform based-depth routing(BDR)in harsh conditions;(3)node self-recovery time is critical to network survivability;(4)traditional degree-based critical node metrics are inadequate for weak-communication UUSNs.These results provide a theoretical foundation for designing robust survivability mechanisms in weak-communication UUSNs. 展开更多
关键词 Weak communication Underwater unmanned swarm networks(UUSNs) Link success probability Cascading failure Node self-recovery Survivability analysis
在线阅读 下载PDF
CEFCO 2026 An Era of Transformation:Stronger Links,Smarter Futures
15
作者 Zhou Dongyang 《China's Foreign Trade》 2026年第1期8-10,共3页
The China Expo Forum for International Cooperation(CEFCO)2026 was held in Wuhan,Hubei Province,China,on January 22.The opening ceremony was attended by Li Qing Shuang,Vice President of the China Council for the Promot... The China Expo Forum for International Cooperation(CEFCO)2026 was held in Wuhan,Hubei Province,China,on January 22.The opening ceremony was attended by Li Qing Shuang,Vice President of the China Council for the Promotion of International Trade(CCPIT);Zhu Yuji,Deputy Secretary of the Hubei Provincial Committee of the Communist Party of China;Sheng Yue Chun,Member of the Standing Committee of the Hubei Provincial Committee of the Communist Party of China and Secretary of the Wuhan Municipal Committee;Punita Bhansal,President of the Global Association of the Exhibition Industry(UFI);Marsha Flanagan,President and CEO of the International Association of Exhibitions and Events(IAEE);Vincent Polito,CEO of the Society of Independent Show Organizers(SISO);and Leonie Ashford,Board Member of the International Congress and Convention Association(ICCA). 展开更多
关键词 smarter futures China expo forum international cooperation cefco exhibition industry wuhan stronger links international cooperation TRANSFORMATION global association exhibition industry ufi
在线阅读 下载PDF
Unit-Linking PCNN中的彩色图像边缘检测 被引量:2
16
作者 薛锦树 聂仁灿 +1 位作者 周冬明 赵东风 《计算机工程与应用》 CSCD 北大核心 2011年第17期188-191,共4页
PCNN模型具有相似群神经元同步发放脉冲的特性,适合于图像分割。对彩色图像的亮度分量进行对数变换,使其更符合人眼的视觉特性;在PCNN进行彩色图像R、G、B三分量分割的过程中,利用遗传算法进行神经元关键参数的选择,利用偏态指标进行迭... PCNN模型具有相似群神经元同步发放脉冲的特性,适合于图像分割。对彩色图像的亮度分量进行对数变换,使其更符合人眼的视觉特性;在PCNN进行彩色图像R、G、B三分量分割的过程中,利用遗传算法进行神经元关键参数的选择,利用偏态指标进行迭代控制;在Unit-Linking PCNN模型中实现R、G、B三分量分割图的边缘检测,利用加权合并策略得到最终的边缘检测结果。仿真结果表明,该方法得到的结果体现了图像中更多的轮廓细节,具有很好的自适应性。 展开更多
关键词 Unit—linking脉冲耦合神经网络 RGB空间 彩色图像分割 彩色图像边缘检测
在线阅读 下载PDF
A Brief Analysis of the Self-correction Model——from the View of Linking Theory
17
作者 佘阿莉 《教师》 2017年第32期78-79,共2页
Based on the theory of the post method pedagogy and the teaching practice,this paper proposes a new teaching model,the self-correction model,and explains it from the point of view of linking theory.
关键词 SELF-CORRECTION model linking THEORY CONCEPT implications
在线阅读 下载PDF
Novel Mobility Formula for Parallel Mechanisms Expressed with Mobility of General Link Group 被引量:14
18
作者 ZHANG Yitong LU Wenjuan +3 位作者 MU Dejun YANG Yandong ZHANG Lijie ZENG Daxing 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2013年第6期1082-1090,共9页
The determination of virtual constraints is always one of the key and difficult problems in traditional mobility calculation.To make mobility calculation simple,considering avoiding virtual constraints,some new formul... The determination of virtual constraints is always one of the key and difficult problems in traditional mobility calculation.To make mobility calculation simple,considering avoiding virtual constraints,some new formulae have been presented,however these formulae can hardly intuitively reflect general link group's restrictions on output member and its influences on independence of output parameters,which is premise to the judgment of the properties of mobility.Towards the problem to reveal the intrinsic relationship between the degree of freedom(DOF)of a mechanism,the link group,and the dimension of output parameters,also to avoid determination of virtual constraint,based on the new concepts of the"DOF of general link group"and"node parameters",a new formula in the calculation of the mobility of mechanisms is presented that is expressed with DOFs of the general link groups and rank of motion parameters of base point of the output link.It is named GOM(mobility of groups and output parameter)formula.On the basis of new concepts of"effective parameters"and"invalid parameters",a rule is put forward for solving the DOF of mechanisms with invalid parameters by GOM formula,that is,the base point parameters are the subset of effective parameters of link group.Thereafter,several examples are enumerated and the results coincide with the prototype data,which proves the validity of the proposed formula.Meanwhile,it is obtained that the necessary and sufficient condition for the judgment of output parameters independence is that each of the DOF of the link group is not less than zero.The proposed formula which is simple in calculation provides theoretical basis for the judgment of independence of output parameters and provides references for type synthesis of novel parallel mechanisms with independence requirements of their output parameters. 展开更多
关键词 parallel mechanism degree of freedom general link group output parameters
在线阅读 下载PDF
Analysis of Thermal-Fluid-Structure Coupling and Resonance Forecast for Link Butterfly Valve Under Small Opening 被引量:9
19
作者 LI Shuxun ZHU Lu +3 位作者 WANG Weibo XIAO Kuijun XU Xiaogang ZHANG Baosheng 《Journal of Shanghai Jiaotong university(Science)》 EI 2019年第3期341-350,共10页
When the link butterfly valve operates at a small opening degree in high temperature working conditions,it is prone to the problem that the valve is stuck,the strength is insufficient and the butterfly plate is violen... When the link butterfly valve operates at a small opening degree in high temperature working conditions,it is prone to the problem that the valve is stuck,the strength is insufficient and the butterfly plate is violently vibrating.This paper shows simulation experiments of both thermal-fluid-structure coupling and resonance forecast about DN600 link butterfly valve in the working conditions of 250℃and 0.5 MPa by ANSYS software.The medium is mixed with compressed air and flue gas.Flow field characteristics of the valve and stress deformation,modal and flow-induced vibration of butterfly plate are analyzed when the valve opening is less than 30%.The results indicate that,when the valve opening is less than 30%,fluid flow is relatively smooth in front of butterfly plate,a large number of vortexes are found behind the butterfly plate,and fluid flow is greatly chaotic in this position.The equivalent maximum stress and deformation of butterfly plate are relatively large when the valve locates in openings between 10%and 30%;the intensity of the butterfly plate is enough;the axial deformation does not impact opening and closing of the valve.The butterfly plate is likely resonant when the valve opening is less than 10%.The research of this paper provides a crucial reference for flow field characteristics of link butterfly valve,an analysis of intensity and rigidity of butterfly plate,and a resonance forecast of butterfly plate when the valve works in small opening. 展开更多
关键词 link butterfly valve thermal-fluid-structure coupling stress deformation resonance forecast
原文传递
Development and application of a multi-physics and multi-scale coupling program for lead-cooled fast reactor 被引量:9
20
作者 Xiao Luo Chi Wang +4 位作者 Ze-Ren Zou Lian-Kai Cao Shuai Wang Zhao Chen Hong-Li Chen 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2022年第2期40-52,共13页
In this study,a multi-physics and multi-scale coupling program,Fluent/KMC-sub/NDK,was developed based on the user-defined functions(UDF)of Fluent,in which the KMC-sub-code is a sub-channel thermal-hydraulic code and t... In this study,a multi-physics and multi-scale coupling program,Fluent/KMC-sub/NDK,was developed based on the user-defined functions(UDF)of Fluent,in which the KMC-sub-code is a sub-channel thermal-hydraulic code and the NDK code is a neutron diffusion code.The coupling program framework adopts the"master-slave"mode,in which Fluent is the master program while NDK and KMC-sub are coupled internally and compiled into the dynamic link library(DLL)as slave codes.The domain decomposition method was adopted,in which the reactor core was simulated by NDK and KMC-sub,while the rest of the primary loop was simulated using Fluent.A simulation of the reactor shutdown process of M2LFR-1000 was carried out using the coupling program,and the code-to-code verification was performed with ATHLET,demonstrating a good agreement,with absolute deviation was smaller than 0.2%.The results show an obvious thermal stratification phenomenon during the shutdown process,which occurs 10 s after shutdown,and the change in thermal stratification phenomena is also captured by the coupling program.At the same time,the change in the neutron flux density distribution of the reactor was also obtained. 展开更多
关键词 Multi-physics and multi-scale coupling method User-defined functions Dynamic link library Thermal stratification Lead-cooled fast reactor
在线阅读 下载PDF
上一页 1 2 136 下一页 到第
使用帮助 返回顶部