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Numerical simulation for the initial state of avalanche in polydisperse particle systems 认领 引用
1
作者 韩韧 李亭 +2 位作者 迟志鹏 杨晖 李然 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期405-412,共8页
Numerical simulation is employed to investigate the initial state of avalanche in polydisperse particle systems.Nucleation and propagation processes are illustrated for pentadisperse and triadisperse particle systems,... Numerical simulation is employed to investigate the initial state of avalanche in polydisperse particle systems.Nucleation and propagation processes are illustrated for pentadisperse and triadisperse particle systems,respectively.In these processes,particles involved in the avalanche grow slowly in the early stage and explosively in the later stage,which is clearly different from the continuous and steady growth trend in the monodisperse system.By examining the avalanche propagation,the number growth of particles involved in the avalanche and the slope of the number growth,the initial state can be divided into three stages:T1(nucleation stage),T2(propagation stage),T3(overall avalanche stage).We focus on the characteristics of the avalanche in the T2 stage,and find that propagation distances increase almost linearly in both axial and radial directions in polydisperse systems.We also consider the distribution characteristics of the average coordination number and average velocity for the moving particles.The results support that the polydisperse particle systems are more stable in the T2 stage. 展开更多
关键词 avalanche initial state polydisperse particle systems propagation
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Convergence Towards the Population Cross-Diffusion System from Stochastic Many-Particle System 认领 引用 被引量：1
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作者 Yue Li Li Chen Zhipeng Zhang 《Communications in Mathematical Research》 CSCD 2024年第1期43-63,共21页
In this paper,we derive rigorously a non-local cross-diffusion system from an interacting stochastic many-particle system in the whole space.The convergence is proved in the sense of probability by introducing an inte... In this paper,we derive rigorously a non-local cross-diffusion system from an interacting stochastic many-particle system in the whole space.The convergence is proved in the sense of probability by introducing an intermediate particle system with a mollified interaction potential,where the mollification is of algebraic scaling.The main idea of the proof is to study the time evolution of a stopped process and obtain a Gronwall type estimate by using Taylor's expansion around the limiting stochastic process. 展开更多
关键词 Stochastic particle systems cross-diffusion system mean-field limit population dynamics
Research progress on micro-force measurement of a hydrate particle system 认领 引用 被引量：1
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作者 Qiang Luo Wei Li +3 位作者 Zhi-Hui Liu Feng Wang Zhi-Chao Liu Fu-Long Ning 《Petroleum Science》 SCIE EI CAS CSCD 2024年第4期2169-2183,共15页
It remains a great challenge to understand the hydrates involved in phenomena in practical oil and gas systems.The adhesion forces between hydrate particles,between hydrate particles and pipe walls,and between hydrate... It remains a great challenge to understand the hydrates involved in phenomena in practical oil and gas systems.The adhesion forces between hydrate particles,between hydrate particles and pipe walls,and between hydrate particles and reservoir particles are essential factors that control the behaviors of clathrate hydrates in different applications.In this review,we summarize the typical micro-force measurement apparatus and methods utilized to study hydrate particle systems.In addition,the adhesion test results,the related understandings,and the applied numerical calculation models are systematically discussed. 展开更多
关键词 Clathrate hydrates Hydrate particle Micro-force measurements Adhesion Interactions
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Phase Behaviors of Soft-core Particle Systems 认领 引用 被引量：1
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作者 Ning Xu 《Chinese Journal of Polymer Science》 SCIE EI CAS CSCD 2019年第11期1065-1082,共18页
This paper reviews some of our recent works on phase behaviors of particulate systems with a soft-core interaction potential. The potential is purely repulsive and bounded, i.e., it is finite even when two particles c... This paper reviews some of our recent works on phase behaviors of particulate systems with a soft-core interaction potential. The potential is purely repulsive and bounded, i.e., it is finite even when two particles completely overlap. The one-sided linear spring (harmonic) potential is one of the representatives. This model system has been successively employed to study the jamming transition, i.e., the formation of rigid and disordered packings of hard particles, and establish the jamming physics. This is actually based on the "hard" aspect of the potential, because at low densities and when particle overlap is tiny the potential resembles the hard sphere limit. At high densities, the potential exhibits its "soft" aspect: with the increase of density, there are successive reentrant crystallizations with many types of solid phases. Taking advantage of the dual nature of the potential, we investigate the criticality of the jamming transition from different perspectives, extend the jamming scenario to high densities, reveal the novel density evolution of two-dimensional melting, and find unexpected formation of quasicrystals. It is surprising that such a simple potential can exhibit so rich and unexpected phenomena in phase transitions. The phase behaviors discussed in this paper are also highly regarded in polymer science, which may thus shed light on our understanding of polymeric systems or inspire new ideas in studies of polymers. 展开更多
关键词 Phase transitions Soft-core particles Jamming Two-dimensional melting Quasicrystals
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STATIONARY DISTRIBUTIONS OF INFINITE PARTICLE SYSTEMS WITH NONCOMPACT STATE SPACE. 认领 引用 被引量：3
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作者 陈木法 《Acta Mathematica Scientia》 SCIE 1989年第1期7-19,共13页
This paper deals with the preblem of existence and uniqueness of the stationary distributions (abbr., s. d.'s) for the processes constructed in [4] .The main results are stated in § 1. For the reader's co... This paper deals with the preblem of existence and uniqueness of the stationary distributions (abbr., s. d.'s) for the processes constructed in [4] .The main results are stated in § 1. For the reader's convenience we first restate the existence theorems (Theorem 1 and 2) of the processes given in [4]. Then two existence theorems (Theorem 3 and 4) and a uniqueness theorem (Theorem 5) for the s. d.'s of the processes are presented. The last result (Theorem 6), as an application of the previous ones, is about the Schlgl model which comes from nonequilibrium statisticali physics. The details of the proofs of Theorem 3—6 are given in § 2—4. 展开更多
关键词 Pro STATIONARY DISTRIBUTIONS OF INFINITE PARTICLE SYSTEMS WITH NONCOMPACT STATE SPACE
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Cloth Modeling Based on Particle System 认领 引用
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作者 Zhong Yueqi +1 位作者 Wang Shanyuan 《Journal of Donghua University(English Edition)》 EI CAS 2001年第2期41-44,共4页
A physical-based particle system is employed for cloth modeling supported by two basic algorithms, between which one is the construction of the internal and external forces acting on the particle system in terms of KE... A physical-based particle system is employed for cloth modeling supported by two basic algorithms, between which one is the construction of the internal and external forces acting on the particle system in terms of KES-F bending and shearing tests, and the other is the collision algorithm of which the collision detection is carried by means of bi-section of time step and the collision response is handled according to the empirical law for frictionless collision With these algorithms. the geometric state of parcles can be expressed as ordinary differential equationswhich is numerically solved by fourth order Runge- Kutta integration. Different draping figures of cotton fabric and wool fabric prove that such a particle system is suitable for 3D cloth modeling and simulation. 展开更多
关键词 cloth modeling, particle system, empirical data,dynamic animation, numerical simulation, collision algorithm
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Technologies for implicit surfaces sampling with particle systems 认领 引用
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作者 LI Weitao ZHANG Caiming +1 位作者 LIU Qian ZHANG Xin 《Computer Aided Drafting,Design and Manufacturing》 2012年第3期65-70,共6页
Point-based surface has been widely used in computer graphics for modeling, animation, visualization, simulation of liq- uid and so on. Furthermore, particle-based approach can distribute the surface sampling points a... Point-based surface has been widely used in computer graphics for modeling, animation, visualization, simulation of liq- uid and so on. Furthermore, particle-based approach can distribute the surface sampling points and control its parameters according to the needs of the application. In this paper, we examine several kinds of algorithms presented over the last decades, with the main focus on particle sampling technologies for implicit surface. Therefore, we classify various algorithms into categories, describe main ideas behind each categories, and compare the advantages and shortcomings of the algorithms in each category. 展开更多
关键词 implicit surfaces particle sampling minimizing energy
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Highly accurate calibration of particle number portable emissions measurement systems(PN-PEMS)via actual soot charging probability correction 认领 引用
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作者 Haotian Guo Chengxiang Guo +6 位作者 Tongzhu Yu Huaqiao Gui Yixin Yang Zhe Ji Junjie Liu Jiguang Wang Jianguo Liu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2026年第6期1-11,共11页
The upcoming Euro 7 vehicle emissions regulation sets new requirements for calibrating particle number portable emissions measurement systems(PN-PEMS).In current PN concentration calibration methods,arbitrary selectio... The upcoming Euro 7 vehicle emissions regulation sets new requirements for calibrating particle number portable emissions measurement systems(PN-PEMS).In current PN concentration calibration methods,arbitrary selection of aerosolmaterials and incorrect estimation ofmultiply-charged particles lead to calibration deviation.This study proposes a novel,accurate calibration method based on the calibration and correction of the actual charging probability of soot for calibrating PN-PEMS.The accurate calibration results of a PN-PEMS show a maximum reduction of 7.65%in the+1-charging probability deviation and of 3.15%in the counting efficiency deviation.The calibration of the actual charging probability of soot introduces a calibration uncertainty increment of 0.09%-2.71%,and the overall uncertainty is<4.76%,whichmakes the calibration results more credible.The interaction of calibration aerosols of different physicochemical properties with the condensation particle counter working fluid and catalytic stripper device is the main reason for the different PN-PEMS calibration results.The calibration of the actual charging probability of particles is the fundamental method to eliminate the calibration deviation caused by the estimation and correction of multiply-charged particles. 展开更多
关键词 Accurate calibration Portable emissions measurement systems(PEMS) Particle number(PN) Soot Charging probability Multiply-charged correction
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CFD-DEM investigation of fluidization of the non-monodisperse particle system in a spouted bed 认领 引用
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作者 Dianyu E Yiliu Wu +5 位作者 Yingming Wen Weifu Sun Kaiwei Chu Jin Xu Huaqing Ma Jiaxin Cui 《Particuology》 SCIE EI CAS CSCD 2025年第10期51-63,共13页
Spouted bed is a type of fluidized bed that has been widely used in various industrial processes because of its excellent mass and heat transfer efficiency.In practical applications,the fluidization of the multicompon... Spouted bed is a type of fluidized bed that has been widely used in various industrial processes because of its excellent mass and heat transfer efficiency.In practical applications,the fluidization of the multicomponent particle system containing non-spherical particles is frequently encountered in spouted beds.To better understand the spouting behaviors of the multicomponent particle system,therefore,this study employs a CFD-DEM(Computational Fluid Dynamics-Discrete Element Method)coupling approach to investigate the spouting behaviors.Spherical particles along with two types of ellipsoidal particles(i.e.,oblate ellipsoid,and prolate ellipsoid)are included in this paper.Through the combination of these three particle types,seven distinct systems(three monodisperse systems,three binary mixtures,and one ternary mixture)are simulated to analyze the effects of particle shape and composition of particle systems on spouting behaviors.The simulation results reveal that introducing non-spherical particles into systems containing either spherical or oblate ellipsoidal particles tends to enhance spouting behaviors,whereas adding spherical particles to prolate ellipsoidal particle systems inclines to suppress it.The addition of non-spherical particles into the spherical particle system can enhance the particle interlocks,and using the oblate particles should have more important influence than prolate particles.Moreover,the influence of particle shape on the spout deflection behaviors is quite complicated,and the use of prolate ellipsoidal particles versus oblate ellipsoidal particles may produce opposite effects.These findings should provide valuable insights for optimizing spouted bed operations involving complex particle mixtures. 展开更多
关键词 Spouted bed CFD-DEM Non-monodisperse particle system Fluidization Non-spherical ellipsoidal particle
Influence of aggregate particle size on fracture behavior and energy evolution of cemented rockfill in the post-peak stage 认领 引用 被引量：1
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作者 Zhu Li Weibing Zhu +4 位作者 Qingdong Qu Jialin Xu Guorui Feng Chunlei Guo Jingmin Xu 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2026年第3期667-685,共19页
Cemented rockfill(CRF)combines structural support with sustainable reuse of coal-derived solid waste.This study integrates digital image correlation,acoustic emission monitoring,and finite-discrete element simulations... Cemented rockfill(CRF)combines structural support with sustainable reuse of coal-derived solid waste.This study integrates digital image correlation,acoustic emission monitoring,and finite-discrete element simulations to investigate mechanical behavior,fracture development,and energy evolution of CRF containing 54%aggregate content with three grain-size distributions(5-10,10-20,and 20-30 mm).Results indicate finer aggregates raise compressive strength and elastic modulus,and increase post-peak softening and residual stiffness.Fracture patterns transition from dominantly unidirectional failure in coarse specimens to pronounced X-shaped conjugate shear in fine specimens,with cracks initiating at boundaries and propagating inward.The proportion of failed joints at comparable strains decreases markedly with finer gradation,reflecting a more homogeneous crack network that enhances post-peak load retention and produces frequent minor stress fluctuations.Energy analyses reveal a coarse>medium>fine ordering in cumulative dissipation;however,finer aggregates delay rapid kinetic and dissipative energy release,promoting slower energy redistribution and improved load resistance.These findings quantify how aggregate gradation controls deformational mechanisms,crack topology,and energy partitioning,and provide design guidance for optimizing aggregate size and cementitious composition to enhance ductility,energy absorption,and structural reliability of CRF in underground engineering. 展开更多
关键词 Cemented rockfill(CRF) Aggregate particle size Post-peak bearing characteristics Crack propagation Energy evolution
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Implicit unified gas kinetic particle method for steady-state solution of multiscale phonon transport 认领 引用 被引量：1
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作者 Hongyu Liu Xiaojian Yang +2 位作者 Chuang Zhang Xing Ji Kun Xu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2026年第2期496-510,共15页
This paper presents a highly efficient implicit unified gas-kinetic particle(IUGKP)method for obtaining steady-state solutions of multi-scale phonon transport.The method adapts and reinterprets the integral solution o... This paper presents a highly efficient implicit unified gas-kinetic particle(IUGKP)method for obtaining steady-state solutions of multi-scale phonon transport.The method adapts and reinterprets the integral solution of the Bhatnagar-Gross-Krook(BGK)equation for time-independent solutions.The distribution function at a given point is determined solely by the surrounding equilibrium states,where the corresponding macroscopic quantities are computed through a weighted sum of equilibrium distribution functions from neighboring spatial positions.From a particle perspective,changes in macroscopic quantities within a cell result from particle transport across cell interfaces.These particles are sampled according to the equilibrium state of their original cells,accounting for their mean free path as the traveling distance.The IUGKP method evolves the solution according to the physical relaxation time scale,achieving high efficiency in large Knudsen number regimes.To accelerate convergence for small Knudsen numbers,an inexact Newton iteration method is implemented,incorporating macroscopic equations for convergence acceleration in the near-diffusive limit.The method also addresses spatial-temporal inconsistency caused by relaxation time variations in physical space through the null-collision concept.Numerical tests demonstrate the method’s excellent performance in accelerating multi-scale phonon transport solutions,achieving speedups of one to two orders of magnitude.The IUGKP method proves to be an efficient and accurate computational tool for simulating multiscale non-equilibrium heat transfer,offering significant advantages over traditional methods in both numerical performance and physical applicability. 展开更多
关键词 Implicit gas kinetic particle method Phonon Boltzmann transport equation Multi-scale heat conduction Steady-state
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Measuring ice lens initiation in soils by particle image velocimetry 认领 引用 被引量：1
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作者 Jinfeng Li Jidong Teng +3 位作者 Haosong He Wenzhang Xu Jenisha Singh Sheng Zhang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2026年第1期761-771,共11页
Ice lens initiation is the core issue in understanding the dynamic process of frost heave.However,there are still limitations to find an adequate criterion for describing the formation of ice lens.A series of one-dime... Ice lens initiation is the core issue in understanding the dynamic process of frost heave.However,there are still limitations to find an adequate criterion for describing the formation of ice lens.A series of one-dimensional freezing tests is designed using the particle image velocimetry(PIV)method to monitor the frost heave and ice lens formation.The results show that the conventional parameters,such as displacement and velocity,cannot be used to track the ice lens formation,while the strain can be employed to detect the ice lens formation and investigate the freezing change patterns.This study proposes strain as a new criterion for assessing ice lens initiation,applicable across various soil types and freezing conditions(constant freezing and ramped freezing).The strain change in the region where the ice lens forms is the largest during the freezing process.Additionally,strain curves at the top of the soil samples can reveal different freezing patterns and distinguish the first and second frost heave stages.This newly developed technology enables continuous,non-destructive monitoring of ice lens initiation across diverse conditions and soil types,enhancing data visualization and three-dimensional modeling of freezing parameters while improving traditional methods by directly measuring velocity and strain in frost heave investigations.The study is expected to enhance the research of ice lens criterion and provide a new perspective for monitoring the freezing process. 展开更多
关键词 Frost heave Ice lens initiation Particle image velocimetry(PIV) Strain
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Particle Swarm Optimization Algorithm for Feature Selection Inspired by Peak Ecosystem Dynamics 认领 引用
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作者 Shaobo Deng Meiru Xie +3 位作者 Bo Wang Shuaikun Zhang Sujie Guan Min Li 《Computers, Materials & Continua》 SCIE EI 2025年第2期2723-2751,共29页
In recent years, particle swarm optimization (PSO) has received widespread attention in feature selection due to its simplicity and potential for global search. However, in traditional PSO, particles primarily update ... In recent years, particle swarm optimization (PSO) has received widespread attention in feature selection due to its simplicity and potential for global search. However, in traditional PSO, particles primarily update based on two extreme values: personal best and global best, which limits the diversity of information. Ideally, particles should learn from multiple advantageous particles to enhance interactivity and optimization efficiency. Accordingly, this paper proposes a PSO that simulates the evolutionary dynamics of species survival in mountain peak ecology (PEPSO) for feature selection. Based on the pyramid topology, the algorithm simulates the features of mountain peak ecology in nature and the competitive-cooperative strategies among species. According to the principles of the algorithm, the population is first adaptively divided into many subgroups based on the fitness level of particles. Then, particles within each subgroup are divided into three different types based on their evolutionary levels, employing different adaptive inertia weight rules and dynamic learning mechanisms to define distinct learning modes. Consequently, all particles play their respective roles in promoting the global optimization performance of the algorithm, similar to different species in the ecological pattern of mountain peaks. Experimental validation of the PEPSO performance was conducted on 18 public datasets. The experimental results demonstrate that the PEPSO outperforms other PSO variant-based feature selection methods and mainstream feature selection methods based on intelligent optimization algorithms in terms of overall performance in global search capability, classification accuracy, and reduction of feature space dimensions. Wilcoxon signed-rank test also confirms the excellent performance of the PEPSO. 展开更多
关键词 Machine learning feature selection evolutionary algorithm particle swarm optimization
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On the dynamics and collisions of settling spheroidal particles 认领 引用 被引量：1
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作者 Xinyu Jiang Lihao Zhao Luca Brandt 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2026年第1期49-63,共15页
In this study,we perform particle-resolved simulations of settling spheroidal particles,considering oblate and prolate spheroids and spheres,and investigate the shape effect on the particle dynamics in suspensions wit... In this study,we perform particle-resolved simulations of settling spheroidal particles,considering oblate and prolate spheroids and spheres,and investigate the shape effect on the particle dynamics in suspensions with volume fraction 1%and 5%.We first examine the single-point statistics of the translational and rotational motion of the settling particles.The horizontal velocity has a symmetrical distribution with standard deviation dependent on the particle shape.The greater horizontal velocity fluctuations of the non-spherical particles,compared to that of spheres,are attributed to the horizontal drift of settling spheroids with oblique orientations induced by the fluid-particle and particle-particle interactions.The fluctuation of particle vertical velocity,instead,is skewed under the effect of wake-induced hydrodynamic interactions.Further,we explore the particle pair statistics,which demonstrate the formation of column-like particle micro-structures for the lowest volume fraction considered.This clustering is more pronounced for spheroidal particles than spheres,due to the stronger attractions among vertically-aligned settling spheroids.Moreover,the particle pair statistics are directly related to the collision rate among the dispersed particles.The local accumulation of oblate/prolate spheroids serves as the major mechanism to promote the particle-particle collisions in dilute suspensions. 展开更多
关键词 Particle sedimentation Dynamics Collision rate Immersed boundary method
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Improved Artificial Rabbit Optimization Algorithm Fused with Particle Swarm Optimization for Wireless Sensor Network Coverage Optimization 认领 引用 被引量：1
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作者 WU Jin SU Zhengdong 《Journal of Shanghai Jiaotong university(Science)》 EI 2026年第2期375-389,共15页
Aiming at the problem of low node coverage during node deployment in wireless sensor network(WSN),an improved artificial rabbit optimization algorithm incorporating particle swarm optimization(ARO-PSO)is proposed for ... Aiming at the problem of low node coverage during node deployment in wireless sensor network(WSN),an improved artificial rabbit optimization algorithm incorporating particle swarm optimization(ARO-PSO)is proposed for network coverage optimization.ARO-PSO successfully combines the stochastic characteristics of ARO and the global characteristics of PSO.Firstly,to optimize the quality of the initial population,Sine chaos mapping is introduced to initialize the population;secondly,to better balance the exploration and exploitation,adaptive settings are made;finally,combined with the characteristics of the ARO energy factor,a population decreasing strategy is introduced to further accelerate the convergence speed of the algorithm.Experimental and analytical comparisons are made with ARO and PSO and 6 other excellent optimizers on 13 benchmark functions.The results show that ARO-PSO largely outperforms the original algorithm.Finally,ARO-PSO is applied to WSN coverage optimization experiments in 2D and 3D environments,and the proposed algorithm exhibits higher network coverage and improves the monitoring quality of the network compared to standard ARO and PSO and other state-of-the-art algorithms.The experimental results fully demonstrate the superiority of the ARO-PSO-based WSN node deployment optimization method. 展开更多
关键词 wireless sensor network(WSN) swarm intelligence optimization artificial rabbits optimization(ARO) particle swarm optimization(PSO) coverage optimization
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Characterizing particle crushing behavior of dry granular soils by acoustic emission 认领 引用
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作者 Wenli Lin Shuyu Tian +5 位作者 Deqi He Xiao Kang Yuhang Chen Ang Liu Maqsood Zain Junichi Koseki 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2026年第5期4050-4063,共14页
This study investigates particle crushing mechanisms in granular soils during shearing through staged triaxial compression experiments performed at prescribed axial strains and varying confining stresses,integrating a... This study investigates particle crushing mechanisms in granular soils during shearing through staged triaxial compression experiments performed at prescribed axial strains and varying confining stresses,integrating a high-performance acoustic emission(AE)measurement system.The study analyzed particle crushing-related parameters using grain size distribution(GSD)-based indices(relative breakage index Bᵣand its rate ΔBr) and AE-based parameters(high-frequency AE hits DHAEand hit rates RHAE).The results confirm the feasibility of high-frequency AEs(>100 kHz)in comprehensive quantification of particle crushing,with a strong linear relationship observed between DHAE and Br.Significant particle crushing occurs within the initial 5%of axial strain,which correlates with the yielding and peak-stress phases.This process yields fragments with a size range of 0.425–2 mm.Increased confining stresses result in a steady rise in Brand DHAE,suggesting that large strains are required for stable particle grading.The evolution trends of different high-frequency AE ranges reveal a shift to complex crushing mechanisms,such as particle abrasion/grinding and corner breakage/particle splitting,highlighting the role of stress and strain levels in influencing particle damage behavior. 展开更多
关键词 Granular materials Particle crushing Acoustic emission(AE) Frequency response Particle damage behavior
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Improving Cyclic Positioning Strategy Accuracy of UWB System in Complex Underground Environments 认领 引用
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作者 Bo Cao Mingrui Jiang +3 位作者 Shibo Wang Menglan Li Linghua Cui Biyong Xu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2026年第4期926-938,共13页
The high-precision automatic positioning technology of the shearer is crucial for the automated and unmanned mining.However,the existing localization approaches commonly deliver inaccurate,unsatisfactory and unreliabl... The high-precision automatic positioning technology of the shearer is crucial for the automated and unmanned mining.However,the existing localization approaches commonly deliver inaccurate,unsatisfactory and unreliable results.In response to this challenge,we propose a novel cyclic positioning strategy to automatically migrate the anchor nodes group(ANG)after the completion of the current cutting operation,thereby achieving long-term period positioning.Meanwhile,we design an innovative technique that appropriately incorporates the shrinkage estimation method based on the minimum mean square error criterion(MMSEC),the improved diversity-guided quantum particle swarm optimization(QPSO),and the extended Kalman filter(EKF)to enhance the localization accuracy of the ultra-wideband(UWB)system in each cycle positioning.Firstly,the cycle positioning strategy and the calculation method of the ANG coordinate position are proposed at the end of fully mechanized mining face.Secondly,the MMSEC method is developed by taking into account of the large measurement noise in the underground environments,and the improved diversity-guided QPSO method is implemented to optimize the result of MMSEC approach.Subsequently,the EKF is executed to suppress the influence of distance residuals on the positioning accuracy and further refine the final estimation accuracy.Lastly,the experimental investigation is performed to evaluate the effectiveness of the proposed cyclic positioning strategy.The experimental results sufficiently demonstrate that the developed MMSEC-QPSO-EKF technique significantly enhances localization accuracy and substantially outperforms the conventional methods,which is capable of achieving better estimation accuracy in each cycle positioning.The proposed cyclic positioning strategy can be successfully implemented,and the achieved accuracies are less than 0.2 m as the ANG is migrated three times,showcasing outstanding localization performance and robustness. 展开更多
关键词 Autonomous positioning diversity-guided quantum particle swarm optimization (QPSO) migration strategy minimum mean square error criterion (MMSEC) underground environment
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Particle size-driven rare earth elements pollution,source and child health risks in Beijing kindergarten dust 认领 引用
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作者 Peng Wang Jian Hu +5 位作者 Wenmin Ma Qian Zhang Liyan Tian Tingyi Liu Houyi Zheng Guilin Han 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2026年第7期589-596,共8页
The concentrations and sources of rare earth elements(REEs) in urban dust are strongly affected by particle size.This study investigates the contamination,sources,and health risks of REEs in re-suspended dust(RPD)and ... The concentrations and sources of rare earth elements(REEs) in urban dust are strongly affected by particle size.This study investigates the contamination,sources,and health risks of REEs in re-suspended dust(RPD)and fine dust(FD) from Beijing kindergartens.Results indicate Ce and Eu concentrations in RPD,and La,Ce,Pr,Nd,Sm,Eu,Gd,and Tb concentrations in FD slightly exceed local background levels.Both RPD and FD are classified as non-polluted levels,with notable enrichment of light rare earth elements(LREEs).Although RPD and FD share similar anthropogenic and natural sources,their contributions differ significantly:RPD reflects stronger anthropogenic influences on RPD and FD demonstrate heightened REE affinity due to its finer particle size.Health risk assessments reveal that children face higher exposure to health risks than adults,primarily through with oral ingestion.Despite elevated risks associated with FD compared to RPD,both remain within negligible thresholds.These findings underscore the importance of implementing particle-specific strategies for mitigating REE pollution in urban environments,providing a scientific foundation for safeguarding children's health in kindergarten settings. 展开更多
关键词 Particle size effect Source differences Health risks Rare earth elements Dust
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Modeling particle number concentrations and sources in the Beijing and Shanghai metropolitan areas with the UCD/CIT model 认领 引用
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作者 Yanhong Zhu Jianjiong Mao +6 位作者 Kangjia Gong Xiaodong Xie Qiong Liao Zelong Wang Huaiqiu Xiao Hongguang Liao Jianlin Hu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2026年第8期723-732,共10页
Particle number concentration(PNC)is a crucial parameter for evaluating the environment,climate,and health effects of particulate matter.Although PNC observation studies have been conducted at various locations,its sp... Particle number concentration(PNC)is a crucial parameter for evaluating the environment,climate,and health effects of particulate matter.Although PNC observation studies have been conducted at various locations,its spatiotemporal variations and source contributions in China remain unclear.In this study,the University of California,Davis/California Institute of Technology air quality model was updated and applied to predict the concentrations and source contributions of particle number in the Beijing and Shanghai metropolitan areas in2017(April and July).The comparison of the average of binary and ternary nucleation results against observations shows that good agreement is found for Beijing in April(the normalized mean bias(NMB)=-0.12)and for Shanghai in April(NMB=0.28)and July(NMB=-0.10).Nucleation is the largest source of PNC in nucleation mode,contributing>90%(except for 40%in July of Beijing,likely due to other unaccounted nucleation schemes such as organic nucleation).For PNC in Aitken mode,the two largest sources are transportation(28%-45%in Beijing,15%-35%in Shanghai)and nucleation(14%-45%,27%-73%).In addition,residential(18%-22%)is also important in Beijing.For PNC in accumulation mode,industry is the largest source,contributing over38%.PNC from power plant and industry is high near the sources and shows sharp spatial gradient.PNC from residential and transportation is high in urban centers,while PNC from nucleation is higher in relatively clean suburban regions than in the polluted urban center regions in the two cities.Modeling PNCs and sources are useful in future control strategies and epidemiological studies. 展开更多
关键词 Particle number concentration Spatiotemporal variation Source contribution Nucleation
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Branch architecture of Tetraena mongolica Maxim. controls particle size distribution of nebkha sediments 认领 引用
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作者 ZHAI Bo DANG Xiaohong +3 位作者 LIU Jing LIU Xiangjie CHEN Xiaona LIU Yajing 《Journal of Arid Land》 SCIE CAS CSCD 2026年第5期851-867,共17页
The formation of desert shrub sand piles(nebkhas)is attributed to the obstruction and subsequent deposition of migrating sand by the shrub itself.However,the relationship between sediment particle size distribution an... The formation of desert shrub sand piles(nebkhas)is attributed to the obstruction and subsequent deposition of migrating sand by the shrub itself.However,the relationship between sediment particle size distribution and shrub branch architecture remains inadequately understood.In August 2020,field investigations were conducted on Tetraena mongolica Maxim.shrubs in the Bayan Engger Desert Nature Reserve,located on the Ordos Plateau in Inner Mongolia Autonomous Region,China.Crown morphological parameters of T.mongolica shrubs and associated nebkhas were systematically measured alongside branch architectures.A one-way analysis of variance(ANOVA)was used to identify differences in branch architectures among various levels,while correlation analysis and model fitting were applied to establish the relationship between crown and nebkha morphological parameters.Path analysis was utilized to identify the key branch architectures that influence crown development.Furthermore,sediment redistribution characteristics of nebkhas were quantified,and principal component analysis combined with regression models was utilized to elucidate the contributions of key branch architectures and sensitive particle size fractions to nebkha deposition.Results indicated that the step-by-step branch ratio(SBR)initially increased from the lower branches to the outermost branches before subsequently decreasing.Additionally,branch angle significantly increased(P<0.0500),whereas both the branch length and the ratio of branch diameters(RBD)significantly decreased toward the exterior of the shrub(P<0.0500).Expansion of crown area significantly enhanced nebkha volume,demonstrating a strong linear relationship(P<0.0010).As the primary contact surface for trapping wind-blown sand,the silhouette area of the shrub initially increased and then decreased from bottom to top.Notably,the silhouette area of the 10-30 cm height layer played a crucial role in promoting nebkha volume expansion(P<0.0100).Path analysis further revealed that the key branch architectures promoting crown area expansion were the step-by-step branch ratio between the third-level and fourth-level branches(SBR3:4),followed by the fourth-level branch length(BLL4),the third-level branch angle(BAL3),and the ratio of branch diameters between the fourth-level and third-level branches(RBD4:3).Under the continuous interception of sediments by branches and leaves,the proportion of surface sediment with a particle size of 100.00-250.00μm reached 51.07%,indicating a significant increase in fine-sized particles.Further analysis confirmed that SBR3:4,BLL4,BAL3,and sediments within the 50.00-100.00μm particle size range were the primary contributors to nebkha deposition.These results demonstrate that the branch characteristics of T.mongolica shrubs near the ground surface promote fine sediment accumulation and nebkha development by regulating crown expansion.The findings reveal the unique adaptation mechanisms of rare and endangered plants in nebkha microhabitats and provide a scientific basis for ecological windbreak and sand-fixation projects in the desert transition zones of arid and semi-arid regions. 展开更多
关键词 Tetraena mongolica Maxim. nebkhas branch architecture particle size distribution nebkha formation Ordos Plateau
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