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Regression Method for Rail Fastener Tightness Based on Center-Line Projection Distance Feature and Neural Network

Chinese Journal of Mechanical Engineering 2024年第2期37卷 356-371页

作者： Yuanhang wang Duxin liu Sheng Guo Yifan Wu Jing liu Wei Li Hongjie wang Robotics Research Center School of MechanicalElectronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China China Construction Industrial&Energy Engineering Group Co. Ltd.Nanjing 210023China

In the railway system,fasteners have the functions of damping,maintaining the track distance,and adjusting the track ***,routine maintenance and inspection of fasteners are important to ensure the safe operation of track ***,assessment methods for fastener tightness include manual observation,acoustic wave detection,and image *** are limitations such as low accuracy and efficiency,easy interference and misjudgment,and a lack of accurate,stable,and fast detection *** at the small deformation characteristics and large elastic change of fasteners from full loosening to full tightening,this study proposes high-precision surface-structured light technology for fastener detection and fastener deformation feature extraction based on the center-line projection distance and a fastener tightness regression method based on neural ***,the method uses a 3D camera to obtain a fastener point cloud and then segments the elastic rod area based on the iterative closest point algorithm *** component analysis is used to calculate the normal vector of the segmented elastic rod surface and extract the point on the centerline of the elastic *** point is projected onto the upper surface of the bolt to calculate the projection ***,the mapping relationship between the projection distance sequence and fastener tightness is established,and the influence of each parameter on the fastener tightness prediction is ***,by setting up a fastener detection scene in the track experimental base,collecting data,and completing the algorithm verification,the results showed that the deviation between the fastener tightness regression value obtained after the algorithm processing and the actual measured value RMSE was 0.2196 mm,which significantly improved the effect compared with other tightness detection methods,and realized an effective fastener tightness regression.

关键词： Railway system Fasteners Tightness inspection Neural network regression 3D point cloud processing

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Quantum squeezing induced nonreciprocal phonon laser

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Science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 20-30页

作者： Tian-Xiang Lu Yan wang Keyu Xia Xing Xiao Le-man Kuang Hui Jing College of Physics and Electronic Information Gannan Normal UniversityGanzhou 341000China Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of Physics and Synergetic Innovation Center for Quantum Effects and ApplicationsHunan Normal UniversityChangsha 410081China Academy for Quantum Science and Technology Zhengzhou University of Light IndustryZhengzhou 450002China College of Engineering and Applied Sciences National Laboratory of Solid State Microstructuresand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210023China

Phonon lasers or coherent amplifications of mechanical oscillations are powerful tools for fundamental studies on coherent acoustics and hold potential for diverse applications,ranging from ultrasensitive force sensing to phononic information ***,we propose the use of an optomechanical resonator coupled to a nonlinear optical resonator for directional phonon *** find that by pumping the nonlinear optical resonator,directional optical squeezing can occur along the pump *** a result,we can achieve the directional mechanical gain using directional optical squeezing,thereby leading to nonreciprocal phonon lasing with a well-tunable directional power *** work proposes a feasible way to build nonreciprocal phonon lasers with various nonlinear optical media,which are important for a wide range of applications,such as directional acoustic amplifiers,invisible sound sensing or imaging,and one-way phononic networks.

关键词： nonreciprocal phonon laser directional quantum squeezing optomechanics

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Microstructured Cantilever Probe on Optical Fiber Tip for Microforce Sensor

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Photonic Sensors 2024年第2期14卷 89-99页

作者： Famei wang Changrui LIAO Mengqiang ZOU Dejun liu Haoqiang HUANG Chao liu Yiping wang Shenzhen Key Laboratory of Ultrafast Laser Micro/Nano manufacturing Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education/Guangdong ProvinceCollege of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China Shenzhen Key Laboratory of Photonic Devices and Sensing Systems for Internet of Things Guangdong and Hong Kong Joint Research Centre for Optical Fibre SensorsState Key Laboratory of Radio Frequency Heterogeneous IntegrationShenzhen UniversityShenzhen 518060China School of Electronics Science Northeast Petroleum UniversityDaqing 163318China

Benefiting from the great advances of the femtosecond laser two-photon polymerization(TPP)technology,customized microcantilever probes can be accurately 3-dimensional(3D)manufactured at the nanoscale size and thus have exhibited considerable potentials in the fields of microforce,micro-vibration,and microforce *** this work,a controllable microstructured cantilever probe on an optical fiber tip for microforce detection is demonstrated both theoretically and *** static performances of the probe are firstly investigated based on the finite element method(FEM),which provides the basis for the structural *** proposed cantilever probe is then 3D printed by means of the TPP *** experimental results show that the elastic constant k of the proposed cantilever probe can be actively tuned from 2.46N/m to 62.35N/*** force sensitivity is 2.5nm/μN,the Q-factor is 368.93,and the detection limit is ***,the mechanical properties of the cantilever probe can be flexibly adjusted by the geometric configuration of the ***,it has an enormous potential for matching the mechanical properties of biological samples in the direct contact mode.

关键词： Optical fiber sensor microforce sensing microstructured cantilever two-photon polymerization

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Optimizing mechanical properties of HIPS fabricated with low-cost desktop 3D printers:investigating the impact of process parameters

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Advances in manufacturing 2024年第2期12卷 379-395页

作者： Jin-Ting Xu Guang-Wei Zhang man-man Chen School of Automotive Engineering Dalian University of TechnologyDalian116024People’s Republic of China

Recently,low-cost desktop three-dimensional(3D)printers,employing the fused deposition modeling(FDM)technique,have gained widespread ***,most users cannot test the strength of printed parts,and little information is available about the mechanical properties of printed high-impact polystyrene(HIPS)parts using desktop 3D *** this study,the user-adjustable parameters of desktop 3D printers,such as crisscross raster orientation,layer thickness,and infill density,were *** experimental plans were designed using the Box-Behnken method,and tensile,3-point bending,and compression tests were carried out to determine the mechanical responses of the printed *** prediction models of the process parameters were regressed to produce the optimal combination of process *** experimental results showcase that the crisscross raster orientation has significant effects on the flexural and compression strengths,but not on the tensile *** an increase in the layer thickness,the tensile,flexural,and compression strengths first decreased and then increased,reaching their minimum values at approximately 0.16 mm layer *** addition,they all increased with an increase of infill *** was demonstrated that when the raster orientation,layer thickness,and infill density were 13.08°/–76.92°,0.09 mm,and 80%,respectively,the comprehensive mechanical properties of the printed HIPS were *** results can help end-users of desktop 3D printers understand the effects of process parameters on the mechanical properties,and offer practical suggestions for setting proper printing parameters for fabricating HIPS parts.

关键词： Desktop three-dimensional(3D)printers Fused deposition modeling(FDM) High-impact polystyrene(HIPS) Process parameters

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Rebuilding the theory of isotope fractionation for evaporation of silicate melts under vacuum condition

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Acta Geochimica 2024年第4期43卷 661-676页

作者： Jie wang Yun liu Research Center for Planetary Science College of Earth and Planetary SciencesChengdu University of TechnologyChengdu 610059China State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China CAS Center for Excellence in Comparative Planetology Hefei 230026China

Isotope eff ects are pivotal in understanding silicate melt evaporation and planetary accretion *** on the Hertz-Knudsen equation,the current theory often fails to predict observed isotope fractionations of laboratory experiments due to its oversimplified ***,we point out that the Hertz-Knudsen-equation-based theory is incomplete for silicate melt evaporation cases and can only be used for situations where the vaporized species is identical to the one in the *** propose a new model designed for silicate melt evaporation under *** model considers multiple steps including mass transfer,chemical reaction,and *** derivations reveal a kinetic isotopic fractionation factor(KIFF orα)αour model=[m(^(1)species)/m(^(2)species)]^(0.5),where m(species)is the mass of the reactant of reaction/nucleation-limiting step or species of diffusion-limiting step and superscript 1 and 2 represent light and heavy isotopes,*** model can eff ectively reproduce most reported KIFFs of laboratory experiments for various elements,i.e.,Mg,Si,K,Rb,Fe,Ca,and ***,the KIFF-mixing model referring that an overall rate of evaporation can be determined by two steps jointly can account for the eff ects of low P_(H2)pressure,composition,and *** addition,we find that chemical reactions,diffusion,and nucleation can control the overall rate of evaporation of silicate melts by using the fitting slope in ln(−ln f)versus ln(t).Notably,our model allows for the theoretical calculations of parameters like activation energy(E_(a)),providing a novel approach to studying compositional and environmental eff ects on evaporation processes,and shedding light on the formation and evolution of the proto-solar and Earth-Moon systems.

关键词： Evaporation Kinetic isotopic fractionation Chemical kinetics Hertz-Knudsen equation CAIS

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Chaotic Map-Based Authentication and Key Agreement Protocol with Low-Latency for Metasystem

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Computers, Materials & Continua 2024年第3期78卷 4471-4488页

作者： Guojun wang Qi liu School of Electronics&Information Engineering Nanjing University of Information Science&TechnologyNanjing210044China Yancheng Polytechnic College Yancheng224000China Jiangsu Province Engineering Research Center of Advanced Computing and Intelligent Services School of SoftwareNanjing University of Information Science and TechnologyNanjingChina

With the rapid advancement in exploring perceptual interactions and digital twins,metaverse technology has emerged to transcend the constraints of space-time and reality,facilitating remote AI-based *** this dynamic metasystem environment,frequent information exchanges necessitate robust security measures,with Authentication and Key Agreement(AKA)serving as the primary line of defense to ensure communication ***,traditional AKA protocols fall short in meeting the low-latency requirements essential for synchronous interactions within the *** address this challenge and enable nearly latency-free interactions,a novel low-latency AKA protocol based on chaotic maps is *** protocol not only ensures mutual authentication of entities within the metasystem but also generates secure session *** security of these session keys is rigorously validated through formal proofs,formal verification,and informal *** confronted with the Dolev-Yao(DY)threat model,the session keys are formally demonstrated to be secure under the Real-or-Random(ROR)*** proposed protocol is further validated through simulations conducted using VMware workstation compiled in HLPSL language and C *** simulation results affirm the protocol’s effectiveness in resisting well-known attacks while achieving the desired low latency for optimal metaverse interactions.

关键词： Metasystem authentication and key agreement chaotic map secure communication

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The unitary subgroups of group algebras for a class of finite 2-groups with the derived subgroup of order 2

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Science China Mathematics 2024年第9期67卷 1989-2018页

作者： Yulei wang Heguo liu Department of Mathematics Henan University of TechnologyZhengzhou 450001China Department of Mathematics Hainan UniversityHaikou 570228China

Let p be a prime and F be a finite field of characteristic *** that FG is the group algebra of the finite p-group G over the field *** V(FG)denote the group of normalized units in FG and let V_(*)(FG)denote the unitary subgroup of V(FG).If p is odd,then the order of V_(*)(FG)is|F|^((|G-1)/2).However,the case p=2 still is *** this paper,the order of V*(FG)is computed when G is a nonabelian 2-group given by a central extension of the form 1→Z_(2^(n))×Z_(2^(m))→G→Z_(2)×…×Z_(2)→1 and G'≌Z_(2),n,m≥***,a conjecture is confirmed,i.e.,the order of V_(*)(FG)can be divisible by|F|^(1/2(|G|+|Ω1(G)|)-1),where Ω_(1)(G)={g∈G|g^(2)=1}.

关键词： normalized unit unitary subgroup inner abelian p-group central extension

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A quadrivalent norovirus vaccine based on a chimpanzee adenovirus vector induces potent immunity in mice

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Virologica Sinica 2024年第4期39卷 675-684页

作者： Yihua Jiang Lingjin Sun Nan Qiao Xiang wang Caihong Zhu man Xing Hui liu Ping Zhou Dongming Zhou Department of Pathogen Biology School of Basic Medical SciencesTianjin Medical UniversityTianjin300070China Shanghai Public Health Clinical Center Fudan UniversityShanghai201508China R&D Centre Chengdu Kanghua Biological Products Co.LtdChengdu610000China Institut Pasteur of Shanghai Chinese Academy of SciencesShanghai200031China

Norovirus(NoV)infection is a major cause of gastroenteritis *** virus poses great challenges in developing vaccines with broad immune protection due to its genetic and antigenic *** date,there are no approved NoV vaccines for clinical ***,we aimed to develop a broad-acting quadrivalent NoV vaccine based on a chimpanzee adenovirus vector,AdC68,carrying the major capsid protein(VP1)of noroviral GI and GII *** to intramuscular(i.m.),intranasal(i.n.),or other prime-boost immunization regimens(i.m.t i.m.,i.m.t i.n.,i.n.t i.m.),AdC68-GI.1-GII.3(E1)-GII.4-GII.17(E3),administered via i.n.t *** higher titers of serum IgG antibodies and higher IgA antibodies in bronchoalveolar lavage fluid(BALF)and saliva against the four homologous VP1s in *** also significantly stimulated the production of blocking antibodies against the four *** response to re-stimulation with virus-like particles(VLP)-GI.1,VLP-GII.3,VLP-GII.4,and VLP-GII.17,the quadrivalent vaccine administered according to the i.n.t *** effectively triggered specific cell-mediated immune responses,primarily characterized by IFN-γ***,the preparation of this novel quadrivalent NoV vaccine requires only a single recombinant adenovirus to provide broad preventive immunity against the major GI/GII epidemic strains,making it a promising vaccine candidate for further development.

关键词： Norovirus(NoV) Quadrivalent vaccine Adenovirus vector

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Optimized air-ground data fusion method for mine slope modeling

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Journal of Mountain Science 2024年第6期21卷 2130-2139页

作者： liu Dan HUANG man TAO Zhigang HONG Chenjie WU Yuewei FAN En YANG Fei State Key Laboratory for Tunnel Engineering China University of Mining and Technology(Beijing)Beijing 100083China Department of Civil Engineering Shaoxing UniversityShaoxing 312000China Department of Computer Science and Engineering Shaoxing UniversityShaoxing 312000China

Refined 3D modeling of mine slopes is pivotal for precise prediction of geological *** at the inadequacy of existing single modeling methods in comprehensively representing the overall and localized characteristics of mining slopes,this study introduces a new method that fuses model data from Unmanned aerial vehicles(UAV)tilt photogrammetry and 3D laser scanning through a data alignment algorithm based on control ***,the mini batch K-Medoids algorithm is utilized to cluster the point cloud data from ground 3D laser ***,the elbow rule is applied to determine the optimal cluster number(K0),and the feature points are ***,the nearest neighbor point algorithm is employed to match the feature points obtained from UAV tilt photogrammetry,and the internal point coordinates are adjusted through the distanceweighted average to construct a 3D ***,by integrating an engineering case study,the K0 value is determined to be 8,with a matching accuracy between the two model datasets ranging from 0.0669 to 1.0373 ***,compared with the modeling method utilizing K-medoids clustering algorithm,the new modeling method significantly enhances the computational efficiency,the accuracy of selecting the optimal number of feature points in 3D laser scanning,and the precision of the 3D model derived from UAV tilt *** method provides a research foundation for constructing mine slope model.

关键词： Air-ground data fusion method Mini batch K-Medoids algorithm Ebow rule Optimal cluster number 3D laser scanning UAV tilt photogrammetry

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Generic Existence of Infinitely many Non-contractible Closed Geodesics on Compact Space Forms

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1674-1684页

作者： Hui liu Yu Chen wang School of Mathematics and Statistics Wuhan UniversityWuhan430072P.R.China School of Mathematics Tianjin Normal UniversityTianjin300384P.R.China

Let M=S^(n)/Γand h be a nontrivial element of finite order p inπ_(1)(Μ),where the integers n,p≥2,Γis a finite abelian group which acts freely and isometrically on the n-sphere and therefore M is diffeomorphic to a compact space *** this paper,we prove that there are infinitely many non-contractible closed geodesics of class[h]on the compact space form with C^(r)-generic Finsler metrics,where 4≤r≤∞.The conclusion also holds for Cr-generic Riemannian metrics for 2≤r≤∞.The proof is based on the resonance identity of non-contractible closed geodesics on compact space forms.

关键词： Compact space forms non-contractible closed geodesics generic Finsler metrics resonance identity

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