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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 478-507页

作者： Cong-hua cheng School of Mathematics and Statistics Zhaoqing UniversityZhaoqing 526061China

In this paper,we consider a system which has k statistically independent and identically distributed strength components and each component is constructed by a pair of statistically dependent elements with doubly type-II censored *** elements(X1,y1),(X2,y2),…,(Xk,yk)follow a bivariate Kumaraswamy distribution and each element is exposed to a common random stress T which follows a Kumaraswamy *** system is regarded as operating only if at least s out of k(1≤s≤k)strength variables exceed the random *** multicomponent reliability of the system is given by Rs,k=P(at least s of the(Z1,…,Zk)exceed T)where Zi=min(Xi,yi),i=1,…,*** Bayes estimates of Rs,k have been developed by using the Markov Chain Monte Carlo methods due to the lack of explicit *** uniformly minimum variance unbiased and exact Bayes estimates of Rs,k are obtained analytically when the common second shape parameter is *** asymptotic confidence interval and the highest probability density credible interval are constructed for Rs,*** reliability estimators are compared by using the estimated risks through Monte Carlo simulations.

关键词： stress-strength model bivariate Kumaraswamy distribution multicomponent reliability doubly Type-II censored scheme interval estimation

Breakup of the Neoarchean supercontinent Kenorland:Evidence from zircon and baddeleyite U-Pb ages of LIP-related mafic dykes in the Coorg Block,southern India

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Geoscience Frontiers 2024年第4期15卷 97-114页

作者： cheng-Xue yang M.Santosh Jarred Lloyd Stijn Glorie y.Anilkumar K.S.Anoop Pin Gao Sung-Won Kim School of Earth Sciences and Resources China University of Geosciences BeijingBeijing 100083PR China Institute of Earth Sciences China University of Geosciences BeijingBeijing 100083PR China Department of Earth Sciences University of AdelaideAdelaide SAAustralia Department of Geology University of KeralaKariavattomTrivandrumIndia Geology Division Korea Institute of Geoscience and Mineral ResourcesDaejeon 34132Republic of Korea

The Coorg Block in southern Peninsular India is one of the oldest crustal blocks on Earth that preserves the evidence for continental crust formation during the Paleo-Mesoarchean through subductionrelated arc magmatism,followed by granulite facies metamorphism in the *** this study,we report for the first time,the'bar codes'of a major Paleoproterozoic Large Igneous Province in the Coorg Block through the finding of mafic dyke *** gabbroic dykes from the Coorg Block,dom-inantly composed of plagioclase-pyroxene assemblage,show a restricted range in SiO_(2)values of 50.04-51.27 wt.%,and exhibit a sub-alkaline tholeiitic *** rocks show relatively flat LREE and constant HREE patterns and lack obvious Eu *** element modeling suggests that the dyke swarm was fed from a melt that originated at a shallow mantle level in the spinel stability *** grains are rare in the gabbro samples and those separated from two samples yielded 207Pb/206Pb weighted mean dates of 2214±12 Ma and 2221±7 *** grains show magmatic features with depleted LREE and enriched HREE and positive Ce and negative Eu *** grains were dated from five gabbro samples which yielded 207Pb/206Pb weighted mean ages ranging between 2217±7 Ma and 2228±10 *** combined data show a clear age peak at ca.2.2 *** mafic dykes in the Coorg Block show geochemical similarities with ca.2.2 Ga mafic dyke swarms in different regions of the Dharwar and other cratons in Peninsular India and elsewhere on the *** data also support the inference that the global mafic magmatism at ca.2.2 Ga was linked with intracontinental rifting of the Archean cratons through mantle upwelling or plume *** correlate the mafic dyke swarms in the Coorg Block with attempted rifting of the Neoarchean supercontinent Kenorland.

关键词： Mafic dyke swarm Paleoproterozoic Large Igneous Province Geochronology Continental rifting Neoarchean supercontinent

Development of Multi-Agent-Based Indoor 3D Reconstruction

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Computers, Materials and Continua 2024年第1期81卷 161-181页

作者： cheng H.C. Hong F.Z. Hussain B. Wang y. yue C.P. Optical Wireless Lab Department of Electronic and Computer Engineering The Hong Kong University of Science and Technology Hong Kong

Large-scale indoor 3D reconstruction with multiple robots faces challenges in core enabling technologies. This work contributes to a framework addressing localization, coordination, and vision processing for multi-agent reconstruction. A system architecture fusing visible light positioning, multi-agent path finding via reinforcement learning, and 360° camera techniques for 3D reconstruction is proposed. Our visible light positioning algorithm leverages existing lighting for centimeter-level localization without additional infrastructure. Meanwhile, a decentralized reinforcement learning approach is developed to solve the multi-agent path finding problem, with communications among agents optimized. Our 3D reconstruction pipeline utilizes equirectangular projection from 360° cameras to facilitate depth-independent reconstruction from posed monocular images using neural networks. Experimental validation demonstrates centimeter-level indoor navigation and 3D scene reconstruction capabilities of our framework. The challenges and limitations stemming from the above enabling technologies are discussed at the end of each corresponding section. In summary, this research advances fundamental techniques for multi-robot indoor 3D modeling, contributing to automated, data-driven applications through coordinated robot navigation, perception, and modeling. © 2024 The Authors. Published by Tech Science Press.

关键词： 3D reconstruction multi-agent path finding Multi-agent system multi-robot human collaboration reinforcement learning visible light communication visible light positioning

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

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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

Reduction of dinitrogen to ammonia on doped three-atom clusters Nb_(2)M(M=Sc to Cu & y to Ag)

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Rare Metals 2024年第8期43卷 3810-3818页

作者： Ran cheng Chao-Nan Cui Zhi-Xun Luo Beijing National Laboratory for Molecular Science(BNLMS) State Key Laboratory for Structural Chemistry of Unstable and Stable SpeciesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China School of Chemical Science University of Chinese Academy of SciencesBeijing 100049China

Catalytic reduction of dinitrogen to ammonia under mild conditions remains an attractive topic for the purpose of lowering energy ***-atom metal clusters have been proved an ideal model to explore highly efficient catalysts taking advantage of unique geometric/electronic structures and cooperative active *** a study of N2 activation and reduction on seventeen bimetallic Nb_2M(M=Sc to Cu,and y to Ag) clusters was *** key processes for ammonia fixation(namely nitrogen activation,hydrogenation,and ammonia desorption) are fully studied,and three preferred systems(Nb_2Ni,Nb_2Rh and Nb_2Pd) are highlighted with outstanding catalytic *** d-σ and d-π~* orbital hybridizations between these metal clusters and N_(2) were demonstrated and the internal association with the N≡N bond activation was *** examining the ammonia synthesis on four chosen Nb_(2)M clusters(M=Fe,Ni,Rh and Pd),it can be elucidated that the distal pathway is more favorable than the alternative pathway in these *** work not only clarifies the N_(2) reduction on the bimetallic Nb_(2)M clusters,but also guides efficient bimetallic catalyst design.

关键词： Three-atom cluster catalysis Three-criteria strategy Nitrogen fixation Ammonia synthesis Theoretical calculations

Effects of content and particle size of TiH2 powders on the energy output rules of RDX composite explosives

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Defence Technology（防务技术） 2024年第2期32卷 297-308页

作者： Hao Wang yangfan cheng Shoujun Zhu Zihan Li Zhaowu Shen School of Chemical Engineering Anhui University of Science and TechnologyHuainan 232001China Anhui Engineering Laboratory of Explosive Materials and Technology Anhui University of Science and TechnologyHuainan 232001China School of Engineering Science University of Science and Technology of ChinaHefei 230027China

In order to improve the detonation characteristics of RDX,a RDX-based composite explosive with TiH_(2)powders was *** effects of content and particle size of TiH_(2)powders on thermal safety,shock wave parameters and thermal damage effects of RDX-based composite explosive were studied with the C80 microcalorimeter,air blast experiment system and colorimetric thermometry *** results showed that TiH_(2)powders could enhance the thermal stability of RDX-based composite explosive and increase its ultimate decomposition *** content and particle size of TiH_(2)powders also had significant effects on the thermal safety,detonation velocity,shock wave parameters,fireball temperature and duration of RDX-based composite ***,the differences of TiH_(2)and Ti powders on the detonation energy output rules of RDX-based composite explosives were also compared,showing that TiH_(2)powders had better influences on improving the explosion power and thermal damage effect of RDX-based composite explosives than Ti powders,for the participation of free H_(2)released by TiH_(2)powders in the detonation ***_(2)powders have important research values as a novel energetic additive in the field of military composite explosives.

关键词： RDX Hydrogen storage alloy Air blast After-burn reaction Colorimetric thermometry

Deflagration characteristics of freely propagating flames in magnesium hydride dust clouds

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Defence Technology（防务技术） 2024年第1期31卷 471-483页

作者： Qiwei Zhang yangfan cheng Beibei Zhang Danyi Li Zhaowu Shen School of Chemical Engineering Anhui University of Science and TechnologyHuainan 232001AnhuiPR China School of Civil Engineering and Architecture Anhui University of Science and TechnologyHuainan 232001AnhuiPR China Anhui Engineering Laboratory of Explosive Materials and Technology Anhui University of Science and TechnologyHuainan 232001AnhuiPR China School of Engineering Science University of Science and Technology of ChinaHefei 230027AnhuiPR China

The flame propagation processes of MgH_(2)dust clouds with four different particle sizes were recorded by a high-speed *** dynamic flame temperature distributions of MgH_(2)dust clouds were reconstructed by the two-color pyrometer technique,and the chemical composition of solid combustion residues were *** experimental results showed that the average flame propagation velocities of 23μm,40μm,60μm and 103μm MgH_(2)dust clouds in the stable propagation stage were 3.7 m/s,2.8 m/s,2.1 m/s and 0.9 m/s,*** dust clouds with smaller particle sizes had faster flame propagation velocity and stronger oscillation intensity,and their flame temperature distributions were more even and the temperature gradients were *** flame structures of MgH_(2)dust clouds were significantly affected by the particle sinking velocity,and the combustion processes were accompanied by micro-explosion of *** falling velocities of 23μm and 40μm MgH_(2)particles were 2.24 cm/s and 6.71 cm/s,*** the falling velocities of 60μm and 103μm MgH_(2)particles were as high as 15.07 cm/s and 44.42 cm/s,respectively,leading to a more rapid downward development and irregular shape of the ***,the dehydrogenation reaction had a significant effect on the combustion performance of MgH_(2)*** combustion of H_(2)enhanced the ignition and combustion characteristics of MgH_(2)dust,resulting in a much higher explosion power than the pure Mg *** micro-structure characteristics and combustion residues composition analysis of MgH_(2)dust indicated that the combustion control mechanism of MgH_(2)dust flame was mainly the heterogeneous reaction,which was affected by the dehydrogenation reaction.

关键词： Magnesium hydride dust Flame combustion mechanism Particle size Dust explosion Two-color pyrometer

The corrosion characteristic and mechanism of Mg-5y-1.5Nd-xZn-0.5Zr(x=0,2,4,6 wt.%)alloys in marine atmospheric environment

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Journal of Magnesium and Alloys 2024年第1期12卷 139-158页

作者： Quantong Jiang Dongzhu Lu Liren cheng Nazhen Liu Baorong Hou CAS Key Laboratory of Marine Environmental Corrosion and Bio-fouling Institute of OceanologyChinese Academy of SciencesNo.7 Nanhai RoadQingdao 266071PR China State Key laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesNo.5625 Renmin StreetChangchun 130022PR China Open Studio for Marine Corrosion and Protection Pilot National Laboratory for Marine Science and Technology(Qingdao)No.1 Wenhai RoadQingdao 266071PR China Sanya Institute of Oceanology South China Sea Institute of OceanologyChinese Academy of SciencesZhenzhou RoadSanya 572000PR China

The microstructure and precipitated phases of as-cast Mg-5y-1.5Nd-x Zn-0.5Zr(x=0,2,4,6 wt.%)alloys were investigated by optical microscopy,scanning electron microscopy,energy-dispersive spectrometry and X-ray *** exposure corrosion experiment of these magnesium alloys was tested in South China Sea and KEXUE vessel atmospheric *** corrosion characteristic and mechanism of magnesium alloys of Mg-5y-1.5Nd-x Zn-0.5Zr(x=0,2,4,6 wt.%)alloys were analyzed by weight loss rate,corrosion depth,corrosion products and corrosion *** electrochemical corrosion tests were also measured in the natural *** comprehensive results showed that Mg-5y-1.5Nd-4Zn-0.5Zr magnesium alloy existed the best corrosion resistance whether in the marine atmospheric environment and natural seawater *** depended on the microstructure,type and distribution of precipitated phases in Mg-5y-1.5Nd-4Zn-0.5Zr magnesium *** quantity anodic precipitated phases in the microstructure of Mg-5y-1.5Nd-4Zn-0.5Zr alloy played the key role in the corrosion resistance.

关键词： Marine atmospheric environment Exposure corrosion Magnesium alloy Corrosion rate Corrosion mechanism

Characteristics and demographic factors of traditional Chinese medicine constitution types among elderly individuals in China:A national multistage cluster random study Author links open overlay panel

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Journal of Traditional Chinese Medical Sciences 2024年第3期11卷 257-263页

作者： Jing Xia Minghua Bai Huirong Song Houqin Li Dayan Zhang Mary y.Jiang Ran Chen Feiyu He cheng Ni Center for Studies in Constitution and Reproductive Sciences of Traditional Chinese Medicine Beijing University of Chinese MedicineBeijing 100029China National Institute of TCM Constitution and Preventive Medicine Beijing University of Chinese MedicineBeijing 100029China Huangsi Comprehensive Outpatient Department Beijing Tongrentang Healthcare Industry Investment Group CompanyBeijing 100032China Zhangjiakou Second Traditional Chinese Medicine Hospital Zhangjiakou 076250China Faculty of Medicine The Chinese University of Hong KongHong Kong 999077China

Objective To reveal the distribution characteristics and demographic factors of traditional Chinese medicine(TCM)constitution among elderly individuals in *** Elderly individuals from seven regions in China were selected as samples in this study using a multistage cluster random sampling *** basic information questionnaire and Constitution in Chinese Medicine Questionnaire(Elderly Edition)were *** statistical analysis,chi-squared tests,and binary logistic regression analysis were *** The single balanced constitution(BC)accounted for 23.9%.The results of the major TCM constitution types showed that BC(43.2%)accounted for the largest proportion and unbalanced constitutions ranged from 0.9%to 15.7%.East China region(odds ratio[OR]=2.097;95%confidence interval[CI],1.912 to 2.301),married status(OR=1.341;95%CI,1.235 to 1.457),and managers(OR=1.254;95%CI,1.044 to 1.505)were significantly associated with ***>70 years was associated with qi-deficiency constitution and blood stasis constitution(BSC).Female sex was significantly associated with yang-deficiency constitution(OR=1.646;95%CI,1.52 to 1.782).Southwest region was significantly associated with phlegm-dampness constitution(OR=1.809;95%CI,1.569 to 2.086).North China region was significantly associated with inherited special constitution(OR=2.521;95%CI,1.569 to 4.05).South China region(OR=2.741;95%CI,1.997 to 1.3.763),Central China region(OR=8.889;95%CI,6.676 to 11.835),senior middle school education(OR=2.442;95%CI,1.932 to 3.088),and managers(OR=1.804;95%CI,1.21 to 2.69)were significantly associated with *** This study defined the distribution characteristics and demographic factors of TCM constitution in the elderly *** and improving unbalanced constitutions,which are correlated with diseases,can help promote healthy aging through the scientific management of these demographic factors.

关键词： Constitution in Chinese Medicine Questionnaire(Elderly Edition) Body constitution Multistage cluster random sampling Demographic factors Elderly individuals

Infiltration,runoff,and slope stability behaviors of infinite slope with macropores based on an improved Green–Ampt model

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Journal of Mountain Science 2024年第7期21卷 2220-2235页

作者： LI Shanghui WU Guoxiong QUE yun JIANG Zhenliang cheng Gaoyun College of Intelligent Construction Fuzhou University of International Studies and TradeFuzhou 350202China College of Civil Engineering Chongqing Jiao Tong UniversityChongqing 400074China Chongqing Vocational College of Architectural Engineering Chongqing 400072China College of Civil Engineering Fuzhou UniversityFuzhou 350000China Department of Civil and Environmental Engineering Hong Kong University of Science and TechnologyHong Kong 999077China T.y.Lin International Engineering Consulting(China)Co.Ltd Chongqing 401120China

Infiltration–runoff–slope instability mechanism of macropore slope under heavy rainfall is *** paper studied its instability mechanism with an improved Green–Ampt(GA)model considering the dual-porosity(i.e.,matrix and macropore)and ponding condition,and proposed the infiltration equations,infiltration–runoff coupled model,and safety factor calculation *** show that the infiltration processes of macropore slope can be divided into three stages,and the proposed model is rational by a comparative *** wetting front depth of the traditional unsaturated slope is 17.2%larger than that of the macropore slope in the early rainfall stage and 27%smaller than that of the macropore slope in the late rainfall ***,macropores benefit the slope stability in the early rainfall but not in the *** flow does not occur initially but becomes pronounced with increasing rainfall *** equal depth of the wetting front in the two domains is regarded as the onset criteria of macropore *** analysis shows that macropore flow is delayed by increasing proportion of macropore domain(ω_(f)),whereas promoted by increasing ratio of saturated permeability coefficients between the two domains(μ).The increasing trend of ponding depth is sharp at first and then grows ***,when rainfall duration is less than 3 h,ωf andμhave no significant effect on the safety factor,whereas it decreases with increasingωf and increases with increasingμunder longer duration(≥3 h).With the increase ofω_(f),the slope maximum instability time advances by 10.5 h,and with the increase ofμ,the slope maximum instability time delays by 3.1 h.

关键词： Macropore slope Green–Ampt infiltration model Equivalent wetting front Ponding response time Slope stability