检索结果-南通市图书馆

Location monitoring approach of underground pipelines using time-sequential images

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Underground Space 2024年第2期15卷 59-75页

作者： Haoruo Xu Lei he Yuyang Chu Junchen he Huaiguang Xiao Chengmeng Shao School of Civil Engineering Southeast UniversityNanjing 210096JiangsuChina The 3rd branch China Railway 16th Bureau Group Co.LTDHuzhou 313000ZhejiangChina

The location monitoring of underground pipelines is of utmost significance as it helps the effective management and maintenance of the pipelines,and facilitates the planning of nearby projects,preventing damage to the ***,currently there is a serious lack of data on the locations of underground *** paper proposes an image-based approach for monitoring the locations of underground pipelines by combing deep learning and visual-based *** proposed approach can build the monitoring model for underground pipelines and characterize their locations through their centroid *** advantages are:(1)simplicity:it only requires time-sequential images of the inner walls of underground pipelines;(2)clarity:the location model and the location curve of underground pipelines can be provided quickly;(3)robustness:it can cope with some existing problems in underground pipelines,such as light variations and small viewing angles.A lightweight approach for monitoring the locations of underground pipelines is *** proposed approach’s effectiveness has been validated through laboratory simulation experiments,demonstrating accuracy at the millimeter level.

关键词： Underground pipelines Location monitoring Time-sequential images Visual-based reconstruction Deep learning

Dual-functional poly(2-methyl-2-oxazoline)/poly(2-(dimethylamine)ethyl methacrylate)mixed brushes with switchable protein adsorption and antibacterial properties

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 Chemical Engineering 2024年第2期66卷 19-30页

作者： Kang he Liangyu Zhu Yanmei Wang CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China

herein,binary mixed brushes consisting of poly(2-methyl-2-oxazoline)(PMOXA)and poly(2-(dimethylamine)ethyl methacrylate)(PDMAEMA)with different chain lengths were fabricated by successive grafting of NH_(2)-terminated PMOXA and SH-terminated PDMAEMA onto polydopamine-anchored *** mixed-brush coating was characterized by variable-angle spectroscopic ellipsometry,X-ray photoelectron spectroscopy,Fourier transform infrared spectroscopy,zeta potential measurements,water contact angle,and atomic force *** mixed brushes showed tunable surface charge,wettability,and surface roughness,depending on the degree of PDMAEMA swelling under varying pH and ionic strength(Ⅰ).Then the adsorption behaviors of pepsin,bovine serum albumin(BSA),γ-globulin,and lysozyme,four very different proteins with regard to isoelectric point,on the mixed brushes coating were studied by using fluorescence microscopy and surface plasmon *** the chain length of PDMAEMA was about twice as long as PMOXA,the mixed brushes not only had high adsorption capacity for pepsin,BSA,and y-globulin but also had a desorption efficiency of 86.9%,87.1%,and 93.5%,*** is explained that electrostatic attraction between the protonated PDMAEMA and positively charged acidic proteins(pepsin and BSA,whose isoelectric points were below the pK_(a) of PDMAEMA)would drive the intensive adsorption(at pH 3,I=10^(-3)mol·L^(-1)for pepsin,and pH 5,I=10^(-5)mol·L^(-1)for BSA),while desorption was dominated by the hydrophilic PMOXA when PDMAEMA was shrinking(at pH 7,I=10^(-1)mol·L^(-1)for pepsin,and pH 9,I=10^(-1)mol·L^(-1)for BSA).Furthermore,the isoelectric precipitation led to the adsorption of neutral protein(γ-globulin,whose isoelectric point was near the pK_a of PDMAEMA)at pH 7,I=10^(-5)mol·L^(-1),while electrostatic repulsion and antifouling PMOXA triggered the desorption of y-globulin at pH 3,I-10^(-1)mol·L^(-1).However,alkaline protein(lysozyme,whose isoelectric point was higher than

关键词： Switchable conformation transition Controllable protein adsorption Mixed brushes Isoelectric point Antibacterial surface

Multi-Robot Cooperative Localization:Time-Varying Unobservable Subspace Analysis and Consistent Algorithm Design

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2024年第5期37卷 1937-1955页

作者： HAO Ning he Fenghua YAO Yu School of Astronautics Harbin Institute of TechnologyHarbin 150000China

This paper investigates the problem of cooperative localization(CL)for a multi-robot system(MRS)under dynamic measurement topology,which involves a group of robots collectively estimating their poses with respect to a common reference frame using ego-motion measurements and robot-to-robot relative *** authors provide a theoretical analysis of the time-varying unobservable subspace and propose a consistent cooperative localization ***,the authors introduce the relative measurement graph(RMG)to represent the relative pose measurements obtained by the MRS at each ***,the authors derive the local observability matrix over a time *** equivalent relationship is established between the local observability matrix and the spectral matrices of the ***,the authors present a method for constructing the unobservable subspace based on the RMG under different topology *** on this analysis,the authors design a consistent cooperative localization algorithm that satisfies the constraints of the time-varying unobservable *** analytical optimal solution is derived for the constrained optimization *** Carlo numerical simulations are conducted to demonstrate the consistency and accuracy of the proposed method.

关键词： Consistency cooperative localization multi-robot system null space relative measurement graph time-varying unobservable subspace

Study on damage mechanism and damage distribution of the rear plate under impact of debris cloud

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第5期35卷 151-167页

作者： Chenyang Wu Xiaowei Chen Qiguang he State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyHaidian DistrictBeijing 100081China School of Mechatronical Engineering Beijing Institute of TechnologyHaidian DistrictBeijing 100081China Institute of Fluid Physics China Academy of Engineering PhysicsMianyang 621900SichuanChina

The debris cloud generated by the hypervelocity impact(HVI)of orbiting space debris directly threatens the spacecraft.A full understanding of the damage mechanism of rear plate is useful for the optimal design of protective *** this study,the hypervelocity yaw impact of a cylindrical aluminum projectile on a double-layer aluminum plate is simulated by the FE-SPH adaptive method,and the damage process of the rear plate under the impact of the debris cloud is analyzed based on the debris cloud *** damage process can be divided into the main impact stage of the debris cloud and the structural response of the rear *** main impact stage lasts a short time and is the basis of the rear plate *** the stage of structure response,the continuous deformation and inertial motion of the rear plate dominate the perforation of the rear *** further analyze the damage mechanism and damage distribution characteristics of the rear plate in ***,the connection between velocity space and position space of the debris cloud is established,which promotes the general analysis of the damage law of debris *** on the relationship,the features of typical damage areas are identified by the localized fine *** the cumulative effect and structural response cause the perforation of rear plate;in the non-perforated area,cratering by the impact of hazardous fragments is the main damage mode of the rear plate.

关键词： Damage of rear plate Debris cloud Secondary impact Hypervelocity yaw impact FE-SPH adaptive method

Prediction of liquid circulation flow rate in RH degasser:improvement of decarburization at low atmospheric pressure

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and steel Research International 2024年第7期31卷 1661-1667页

作者： Gu-jun Chen Sheng-ping he College of Materials Science and Engineering Yangtze Normal UniversityChongqing 400044China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China

The two-fluid model coupled with population balance model was used for simulating the gas-liquid flow in the Ruhrstahl-heraeus(RH)*** predicted circulation flow rate was compared with that measured from a water model experiment to validate the mathematical ***,influence of snorkel immersion depth on liquid circulation flow rate was numerically investigated under an atmospheric pressure of 101 and 84 kPa,*** result indicates that the circulation flow rate of the RH degasser in the high-altitude area was severely reduced because of the decrease in atmospheric ***,increasing the snorkel immersion depth from 0.5 to 0.7 m can compensate for the decrease in atmospheric *** test result indicates that decarburization rate is significantly enhanced by increasing the snorkel immersion *** optimization,the percentage of heats with a final carbon content less than 0.002 wt.%is significantly increased from 22.0%to 96.4%.

关键词： RH degasser Two-fluid model Population balance model-Circulation flow rate Decarburization Snorkel immersion depth

Volume of fluid simulation of single argon bubble dynamics in liquid steel under RH vacuum conditions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and steel Research International 2024年第4期31卷 828-837页

Single argon bubble dynamics in liquid steel under Ruhrstahl-heraeus(RH)vacuum conditions were simulated using the volume of fluid method,and the ideal gas law was used to consider bubble growth due to heat transfer and pressure *** simulation with a constant bubble density was also performed to validate the numerical method,and the predicted terminal bubble shape and velocity were found to agree with those presented in the Grace diagram and calculated by drag correlation,*** simulation results under RH conditions indicate that the terminal bubble shape and velocity cannot be *** primary bubble growth occurs within a rising distance of 0.3 m owing to heating by the high-temperature liquid steel;subsequently,the bubble continues to grow under equilibrium with the hydrostatic *** the initial diameter is 8-32 mm,the bubble diameter and rising velocity near the liquid surface are 80-200 mm and 0.5-0.8 m/s,*** bubble rises rectilinearly with an axisymmetric shape,and the shape evolution history includes an initial sphere,(dimpled)ellipsoid,and spherical cap with satellite bubbles.

关键词： Bubble dynamics Liquid steel Volume of fluid Bubble growth Bubble shape Rising velocity

Chien-physics-informed neural networks for solving singularly perturbed boundary-layer problems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第9期45卷 1467-1480页

作者： Long WANG Lei ZHANG Guowei he The State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Sciences University of Chinese Academy of SciencesBeijing 100049China

A physics-informed neural network(PINN)is a powerful tool for solving differential equations in solid and fluid ***,it suffers from singularly perturbed boundary-layer problems in which there exist sharp changes caused by a small perturbation parameter multiplying the highest-order *** this paper,we introduce Chien's composite expansion method into PINNs,and propose a novel architecture for the PINNs,namely,the Chien-PINN(C-PINN)*** novel PINN method is validated by singularly perturbed differential equations,and successfully solves the wellknown thin plate bending *** particular,no cumbersome matching conditions are needed for the C-PINN method,compared with the previous studies based on matched asymptotic expansions.

关键词： physics-informed neural network(PINN) singular perturbation boundarylayer problem composite asymptotic expansion

Answering reachability queries with ordered label constraints over labeled graphs

在线全文

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2024年第1期18卷 105-117页

作者： Daoliang he Pingpeng YUAN Hai JIN National Engineering Research Center for Big Data Technology and System Services Computing Technology and System LabCluster and Grid Computing LabSchool of Computer Science&TechnologyHuazhong University of Science and TechnologyWuhan 430074China

Reachability query plays a vital role in many graph analysis *** researches proposed many methods to efficiently answer reachability queries between vertex *** many real graphs are labeled graph,it highly demands Label-Constrained Reachability(LCR)query inwhich constraint includes a set of labels besides vertex *** researches proposed several methods for answering some LCR queries which require appearance of some labels specified in constraints in the *** that constraint may be a label set,query constraint may be ordered labels,namely OLCR(Ordered-Label-Constrained Reachability)queries which retrieve paths matching a sequence of ***,no solutions are available for ***,we propose DHL,a novel bloom filter based indexing technique for answering OLCR *** can be used to check reachability between vertex *** the answers are not no,then constrained DFS is ***,we employ DHL followed by performing constrained DFS to answer OLCR *** show that DHL has a bounded false positive rate,and it's powerful in saving indexing time and *** experiments on 10 real-life graphs and 12 synthetic graphs demonstrate that DHL achieves about 4.8-22.5 times smaller index space and 4.6-114 times less index construction time than two state-of-art techniques for LCR queries,while achieving comparable query response *** results also show that our algorithm can answer OLCR queries effectively.

关键词： graph ordered-label-constrained reachability partial index bloom filter query processing

Meta-path reasoning of knowledge graph for commonsense question answering

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2024年第1期18卷 49-59页

作者： Miao ZHANG Tingting he Ming DONG National Engineering Research Center for E-Learning Central China Normal UniversityWuhan 430079China Hubei Provincial Key Laboratory of Artificial Intelligence and Smart Learning Central China Normal UniversityWuhan 430079China National Language Resources Monitoring&Research Center for Network Media Central China Normal UniversityWuhan 430079China School of Computer Central China Normal UniversityWuhan 430079China

Commonsense question answering(CQA)requires understanding and reasoning over QA context and related commonsense knowledge,such as a structured Knowledge Graph(KG).Existing studies combine language models and graph neural networks to model ***,traditional knowledge graph are mostly concept-based,ignoring direct path evidence necessary for accurate *** this paper,we propose MRGNN(Meta-path Reasoning Graph Neural Network),a novel model that comprehensively captures sequential semantic information from concepts and *** MRGNN,meta-paths are introduced as direct inference evidence and an original graph neural network is adopted to aggregate features from both concepts and paths *** conduct sufficient experiments on the CommonsenceQA and OpenBookQA datasets,showing the effectiveness of ***,we conduct further ablation experiments and explain the reasoning behavior through the case study.

关键词： question answering knowledge graph graph neural network meta-path reasoning