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Numerical Study on the Aerodynamic and Fluid−Structure Interaction of An NREL-5MW Wind Turbine

China Ocean Engineering 2024年第3期38卷 363-378页

作者： ZHAO Mi YU Wan-li WANG pi-guang QU Yang DU Xiu-li Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing 100124China State Key Laboratory of Bridge Engineering Safety and Resilience Beijing University of TechnologyBeijing 100124China

A 5-MW wind turbine has been modeled and analyzed for fluid-structure interaction and aerodynamic *** this study, a full-scale model of a 5-MW wind turbine is first developed based on a computational fluid dynamics(CFD) approach, in which the unsteady, noncompressible Reynolds Averaged Navier-Stokes(RANS) method is used. The main focus of the study is to analyze the tower shadow effect on the aerodynamic performance of the wind turbine under different inlet flow conditions. Subsequently, the finite element model is established by considering fluid/structure interactions to study the structural stress, displacement, strain distributions and flow field information of the structure under the uniform wind speed. Finally, the fluid-structure interaction model is established by considering turbulent wind and the tower shadow effect. The variation rules of the dynamic response of the one-way and two-way fluid-structure interaction(FSI) models under different wind speeds are analyzed, and the numerical calculation results are compared with those of the centralized mass model. The results show that the tower shadow effect and structural deformation are the main factors affecting the aerodynamic load fluctuation of the wind turbine, which in turn affects the aerodynamic performance and structural stability of the blades. The structural dynamic response of the coupled model shows significant similarity, while the structural displacement response of the former exhibits less fluctuation compared with the conventional centralized mass model. The one-way fluid-structure interaction(FSI)model shows a higher frequency of stress-strain and displacement oscillations on the blade compared with the two-way FSI model.

关键词： computational fluid dynamics methods(CFD) tower shadow effect aerodynamic performance fluidstructure interaction space flow field

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Analytical Solution and Simplified Formula for Added Mass of Horizontal and Vertical Motions of Truncated Cylinders Under Earthquake Action

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China Ocean Engineering 2024年第1期38卷 54-67页

作者： WANG pi-guang LYU Si-yu QU Yang ZHAO Mi DU Xiu-li State Key Laboratory of Bridge Engineering Safety and Resilience Beijing University of TechnologyBeijing 100124China Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of Tech-nologyBeijing 100124China

This paper investigates the hydrodynamic characteristics of floating truncated cylinders undergoing horizontal and vertical motions due to earthquake excitations in the finite water *** governing equation of the hydrodynamic pressure acting on the cylinder is derived based on the radiation theory with the inviscid and incompressible *** governing equation is solved by using the method of separating variables and analytical solutions are obtained by assigning reasonable boundary *** analytical result is validated by a numerical model using the exact artificial boundary simulation of the infinite *** main variation and distribution characteristics of the hydrodynamic pressure acting on the side and bottom of the cylinder are analyzed for different combinations of wide-height and immersion *** added mass coefficient of the cylinder is calculated by integrating the hydrodynamic pressure and simplified formulas are proposed for engineering *** calculation results show that the simplified formulas are in good agreement with the analytical solutions.

关键词： earthquake hydrodynamic pressure truncated cylinder added mass simplified formula

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Performance evaluation of seven multi-label classification methods on real-world patent and publication datasets

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Journal of Data and Information Science 2024年第2期9卷 81-103页

作者： Shuo Xu Yuefu Zhang Xin An Sainan pi College of Economics and Management Beijing University of TechnologyBeijing 100124China School of Economics&Management Beijing Forestry UniversityBeijing 100083China

Purpose:Many science,technology and innovation(STI)resources are attached with several different *** assign automatically the resulting labels to an interested instance,many approaches with good performance on the benchmark datasets have been proposed for multi-label classification task in the ***,several open-source tools implementing these approaches have also been ***,the characteristics of real-world multi-label patent and publication datasets are not completely in line with those of benchmark ***,the main purpose of this paper is to evaluate comprehensively seven multi-label classification methods on real-world *** limitations:Three real-world datasets differ in the following aspects:statement,data quality,and ***,open-source tools designed for multi-label classification also have intrinsic differences in their approaches for data processing and feature selection,which in turn impacts the performance of a multi-label classification *** the near future,we will enhance experimental precision and reinforce the validity of conclusions by employing more rigorous control over variables through introducing expanded parameter *** implications:The observed Macro F1 and Micro F1 scores on real-world datasets typically fall short of those achieved on benchmark datasets,underscoring the complexity of real-world multi-label classification *** leveraging deep learning techniques offer promising solutions by accommodating the hierarchical relationships and interdependencies among *** ongoing enhancements in deep learning algorithms and large-scale models,it is expected that the efficacy of multi-label classification tasks will be significantly improved,reaching a level of practical utility in the foreseeable ***/value:(1)Seven multi-label classification methods are comprehensively compared on three real-world datasets.(2)The TextCNN and

关键词： Multi-label classification Real-World datasets Hierarchical structure Classification system Label correlation Machine learning

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A highly sensitive ratiometric near-infrared nanosensor based on erbium-hyperdoped silicon quantum dots for iron(Ⅲ) detection

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Journal of Semiconductors 2024年第8期45卷 49-58页

作者： Kun Wang Wenxuan Lai Zhenyi Ni Deren Yang Xiaodong pi State Key Laboratory of Silicon and Advanced Semiconductor Materials&School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027China Institute of Advanced Semiconductors&Zhejiang Provincial Key Laboratory of Power Semiconductor Materials and Devices ZJ-UHangzhou Global Scientific and Technological Innovation CenterZhejiang UniversityHangzhou 311215China

Ratiometric fluorescent detection of iron(Ⅲ)(Fe^(3+))offers inherent self-calibration and contactless analytic ***,realizing a dual-emission near-infrared(NIR)nanosensor with a low limit of detection(LOD)is rather *** this work,we report the synthesis of water-dispersible erbium-hyperdoped silicon quantum dots(Si QDs:Er),which emit NIR light at the wavelengths of 810 and 1540 nm.A dual-emission NIR nanosensor based on water-dispersible Si QDs:Er enables ratiometric Fe^(3+)detection with a very low LOD(0.06μM).The effects of pH,recyclability,and the interplay between static and dynamic quenching mechanisms for Fe^(3+)detection have been systematically *** addition,we demonstrate that the nanosensor may be used to construct a sequential logic circuit with memory functions.

关键词： erbium-hyperdoped silicon quantum dots dual-emission near-infrared nanosensor Fe^(3+)detection sequential logic circuit

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Corneal and intraocular pressure changes associated to the circadian rhythms:a narrative review

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International Journal of Ophthalmology(English edition) 2024年第10期17卷 1921-1928页

作者： Laura Barberán-Bernardos MiguelÁngel Ariza-Gracia David P piñero Department of Optics Pharmacology and AnatomyUniversity of AlicanteSan Vicente del Raspeig 03690AlicanteSpain ARTORG Center for Biomedical Engineering Research University of BernBern 3008Switzerland Department of Ophthalmology(IMQO-Oftalmar) Vithas Medimar International HospitalAlicante 03016Spain

AIM:To synthesize the current body of research regarding the diurnal variations in intraocular pressure(IOP)and corneal biomechanical and morphological parameters,highlighting their significance in various eye ***:A comprehensive review of studies on the diurnal variations of IOP and corneal parameters was *** findings from various studies were assessed,including the Goldmann applanation tonometry(GAT)and non-contact *** on the variations in central corneal thickness(CCT),corneal curvature,and corneal biomechanics measured by the Ocular Response Analyzer system across different population groups was extracted and ***:In both healthy subjects and those with Fuchs dystrophy,IOP and CCT demonstrate marked diurnal *** remains the gold standard for tonometry,with the highest ***,its measurements are influenced by *** patients and those with pseudoexfoliation showed significant diurnal variations in *** biomechanical parameters,especially corneal hysteresis(CH)and the corneal resistance factor(CRF),largely remain stable throughout the day for most of eye conditions,with some ***,the corneal morphology diurnal variation,particularly curvature,yielded mixed conclusions across ***:Circadian rhythms significantly influence various corneal parameters,most notably IOP and *** studies should emphasize standardized approaches larger sample sizes,and delve deeper into less-explored areas,such as the effects of orthokeratology lenses on diurnal biomechanical shifts.

关键词： circadian rhythms intraocular pressure corneal thickness corneal biomechanics corneal curvature

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A semantic vector map-based approach for aircraft positioning in GNSS/GPS denied large-scale environment

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Defence Technology（防务技术） 2024年第4期34卷 1-10页

作者： Chenguang Ouyang Suxing Hu Fengqi Long Shuai Shi Zhichao Yu Kaichun Zhao Zheng You Junyin pi Bowen Xing State Key Laboratory of Precision Measurement Technology and Instruments Tsinghua UniversityBeijing 100084China School of Mechanical and Information Engineering China University of Mining and Technology(Beijing)Beijing 100083China

Accurate positioning is one of the essential requirements for numerous applications of remote sensing data,especially in the event of a noisy or unreliable satellite *** this end,we present a novel framework for aircraft geo-localization in a large range that only requires a downward-facing monocular camera,an altimeter,a compass,and an open-source Vector Map(VMAP).The algorithm combines the matching and particle filter *** vector and correlation between two building contour vectors are defined,and a coarse-to-fine building vector matching(CFBVM)method is proposed in the matching stage,for which the original matching results are described by the Gaussian mixture model(GMM).Subsequently,an improved resampling strategy is designed to reduce computing expenses with a huge number of initial particles,and a credibility indicator is designed to avoid location mistakes in the particle filter *** experimental evaluation of the approach based on flight data is *** a flight at a height of 0.2 km over a flight distance of 2 km,the aircraft is geo-localized in a reference map of 11,025 km~2using 0.09 km~2aerial images without any prior *** absolute localization error is less than 10 m.

关键词： Large-scale positioning Building vector matching Improved particle filter GPS-Denied Vector map

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An Integrated Control Framework for Torque Vectoring and Active Suspension System

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 62-73页

作者： Jiwei Feng Jinhao Liang Yanbo Lu Weichao Zhuang Dawei pi Guodong Yin Liwei Xu Pai Peng Chaobin Zhou School of Mechanical Engineering Southeast UniversityNanjing 211189China School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China School of Mechano-Electronic Engineering Lanzhou University of TechnologyLanzhou 730050China

Four-wheel independently driven electric vehicles(FWID-EV)endow a flexible and scalable control framework to improve vehicle *** paper integrates the torque vectoring and active suspension system(ASS)to enhance the vehicle’s longitudinal and vertical motion control *** the nonlinear characteristic of the tire model leads to a relatively heavier computational *** facilitate the controller design and ease the load,a half-vehicle dynamics system is built and simplified to the linear-time-varying(LTV)*** a model predictive controller is developed by formulating the objective function by comprehensively considering the safety,energy-saving and comfort *** in-wheel motor efficiency and the power loss of tire slip are treated as optimization indices in this work to reduce energy ***,the effectiveness of the proposed controller is verified through the rapid-control-prototype(RCP)*** results demonstrate the enhancement of the energy-saving as well as comfort on the basis of vehicle stability.

关键词： Four-wheel independently driven electric vehicles Tire nonlinearity Linear-time-varying(LTV)model Model predictive control Rapid control prototype

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Defects evolution in n-type 4H-SiC induced by electron irradiation and annealing

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Journal of Semiconductors 2024年第7期45卷 77-83页

作者： Huifan Xiong Xuesong Lu Xu Gao Yuchao Yan Shuai Liu Lihui Song Deren Yang Xiaodong pi State Key Laboratory of Silicon and Advanced Semiconductor Materials&School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027China Key Laboratory of Power Semiconductor Materials and Devices of Zhejiang Province&Institute of Advanced Semiconductors ZJU-Hangzhou Global Scientific and Technological Innovation CenterZhejiang UniversityHangzhou 311200China

Radiation damage produced in 4H-SiC by electrons of different doses is presented by using multiple characterization techniques. Raman spectra results indicate that SiC crystal structures are essentially impervious to 10 Me V electron irradiation with doses up to 3000 kGy. However, irradiation indeed leads to the generation of various defects, which are evaluated through photoluminescence(PL) and deep level transient spectroscopy(DLTS). The PL spectra feature a prominent broad band centered at 500 nm, accompanied by several smaller peaks ranging from 660 to 808 nm. The intensity of each PL peak demonstrates a linear correlation with the irradiation dose, indicating a proportional increase in defect concentration during irradiation. The DLTS spectra reveal several thermally unstable and stable defects that exhibit similarities at low irradiation ***, after irradiating at the higher dose of 1000 kGy, a new stable defect labeled as R_(2)(Ec-0.51 eV) appeared after annealing at 800 K. Furthermore, the impact of irradiation-induced defects on SiC junction barrier Schottky diodes is discussed. It is observed that high-dose electron irradiation converts SiC n-epilayers to semi-insulating layers. However, subjecting the samples to a temperature of only 800 K results in a significant reduction in resistance due to the annealing out of unstable defects.

关键词： 4H-SiC deep level transient spectroscopy(DLTS) photoluminescence(PL) defects

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Multi-dimensional multiplexing optical secret sharing framework with cascaded liquid crystal holograms

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Opto-Electronic Advances 2024年第1期7卷 28-35页

作者： Keyao Li Yiming Wang Dapu pi Baoli Li Haitao Luan Xinyuan Fang Peng Chen Yanqing Lu Min Gu Institute of Photonic Chips University of Shanghai for Science and TechnologyShanghai 200093China Centre for Artificial-Intelligence Nanophotonics School of Optical-Electrical and Computer EngineeringUniversity of Shanghai for Science and TechnologyShanghai 200093China National Laboratory of Solid State Microstructures and College of Engineering and Applied SciencesNanjing UniversityNanjing 210093China

Secret sharing is a promising technology for information encryption by splitting the secret information into different ***,the traditional scheme suffers from information leakage in decryption process since the amount of available information channels is ***,we propose and demonstrate an optical secret sharing framework based on the multi-dimensional multiplexing liquid crystal(LC)*** LC holograms are used as spatially separated shares to carry secret *** polarization of the incident light and the distance between different shares are served as secret keys,which can significantly improve the information security and ***,the decryption condition is also restricted by the applied external voltage due to the variant diffraction efficiency,which further increases the information *** implementation,an artificial neural network(ANN)model is developed to carefully design the phase distribution of each LC *** the advantage of high security,high capacity and simple configuration,our optical secret sharing framework has great potentials in optical encryption and dynamic holographic display.

关键词： holographic encryption optical secret sharing cascaded liquid crystal hologram multi-dimensional multiplexing

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Chiral liquid crystals based on pillararene and supramolecular self-assembly-induced chirality amplification

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Science China Chemistry 2024年第10期67卷 3373-3381页

作者： Bicong Liang Yujie Cheng Xiong Liu Lan Jia Xuehong Wei Qiang Zheng pi Wang Danyu Xia Xuzhou Yan College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China Scientific Instrument Center Shanxi UniversityTaiyuan 030006China School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative MoleculesShanghai Jiao Tong UniversityShanghai 200240China

Macrocyclic liquid crystals combine the unique property of liquid crystals and excellent supramolecular assembly ability of macrocyclic *** is a significant challenge to make rational use of the advantages of macrocyclic compounds to prepare new macrocyclic ***,a type of macrocycles with rigid pillar-shaped frameworks and easy-tofunctionalize property,are excellent building blocks to fabricate liquid crystal ***,the site-selective modification property of pillararene has been rarely exploited to tailor liquid crystal *** reported pillararene-based liquid crystal systems are almost prepared by per-functionalized ***,we report the regulation of chiral liquid crystal behaviors by different derivatization of *** and thermotropic liquid crystals with different chirality were obtained by self-assembly of pillararene with different numbers of cholesterol *** bridge between thermotropic liquid crystal and lyotropic liquid crystal based on pillararene is *** addition,the chirality of the mesogens can be amplified through supramolecular self-assembly driven by noncovalent *** on the different liquid crystal behaviors,the optical signal of the pillararene-based chiral liquid crystals was used to fabricate an information encryption *** work provides a simple strategy to regulate liquid crystal behaviors via pillararene-based mesogens and realizes information encryption through the combination of different types of liquid crystals.

关键词： chiral liquid crystal pillararene self-assembly cholesterol information encryption

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