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Effects of vibration conditions,spatial confinement and friction on mixing and segregation characteristics of mixed pebble beds for CFETR WCCB blanket

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Particuology 2024年第2期85卷 268-279页

作者： Yong liu Chongyang He cong Wang Lei Chen Songlin liu Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei230031China University of Science and Technology of China Hefei230027China Chengdu University Chengdu610106China Zhejiang Lab Hangzhou310000China

This paper presents the study of the dynamic characteristics of confined mixed pebble beds with different friction under different vibration conditions using the discrete element method.Theλsegre-gation index is used to quantify the degree of particle mixing or segregation.The percolation,convection and diffusion mechanisms are responsible for the segregation patterns of the mixed pebble.The results show the degree of segregation can be suppressed by decreasing the vibration acceleration or free space height below a threshold.Further simulation reveals the threshold of vibration acceleration or free space height both are related to the bed height increment which determines the strength of the percolation mechanism.In addition,the strength of percolation and convection becomes weaker by decreasing the friction of particles and walls,which makes the pebbled bed remains in a mixed state under vibration.These findings are significant to clarify the main factors behind the three segregation mechanisms and hence provide solutions to retaining the mixed state of the Li2TiO3&Be12Ti mixed pebble bed.

关键词： Vibration Segregation Binary pebble bed Discrete element method

Brain Cognition Mechanism-Inspired Hierarchical Navigation Method for Mobile Robots

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Journal of Bionic Engineering 2024年第2期21卷 852-865页

作者： Qiang Zou Chengdong Wu Ming cong Dong liu Faculty of Robot Science and Engineering Northeastern UniversityShenyang110819China School of Mechanical Engineering Dalian University of TechnologyDalian116024China

Autonomous navigation is a fundamental problem in robotics.Traditional methods generally build point cloud map or dense feature map in perceptual space;due to lack of cognition and memory formation mechanism,traditional methods exist poor robustness and low cognitive ability.As a new navigation technology that draws inspiration from mammal’s navigation,bionic navigation method can map perceptual information into cognitive space,and have strong autonomy and environment adaptability.To improve the robot’s autonomous navigation ability,this paper proposes a cognitive map-based hierarchical navigation method.First,the mammals’navigation-related grid cells and head direction cells are modeled to provide the robots with location cognition.And then a global path planning strategy based on cognitive map is proposed,which can anticipate one preferred global path to the target with high efficiency and short distance.Moreover,a hierarchical motion controlling method is proposed,with which the target navigation can be divided into several sub-target navigation,and the mobile robot can reach to these sub-targets with high confidence level.Finally,some experiments are implemented,the results show that the proposed path planning method can avoid passing through obstacles and obtain one preferred global path to the target with high efficiency,and the time cost does not increase extremely with the increase of experience nodes number.The motion controlling results show that the mobile robot can arrive at the target successfully only depending on its self-motion information,which is an effective attempt and reflects strong bionic properties.

关键词： Bionic navigation Spatial localization cells Global path planning Hierarchical motion controlling

Quasi-2D weak lensing cosmological constraints using the PDF-SYM method

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 44-58页

作者： Zhenjie liu Jun Zhang Hekun Li Zhi Shen cong liu Department of Astronomy Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Key Laboratory for Particle Physics and Cosmology Shanghai 200240China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China

Cosmic shear statistics,such as the two-point correlation function(2PCF),can be evaluated with the PDF-SYM method instead of the traditional weighted-sum approach.It makes use of the full PDF information of the shear estimators,and does not require weightings on the shear estimators,which can in principle introduce additional systematic biases.This work presents our constraints on S8and?mfrom the shear-shear correlations using the PDF-SYM method.The data we use is from the z-band images of the Dark Energy Camera Legacy Survey(DECa LS),which covers about 10000 deg2with more than 100 million galaxies.The shear catalog is produced by the Fourier Quad method,and well tested on the real data itself with the field-distortion effect.Our main approach is called quasi-2D as we do use the photo-z information of each individual galaxy,but without dividing the galaxies into redshift bins.We mainly use galaxy pairs within the redshift interval between 0.2 and 1.3,and the angular range from 4.7 to 180 arcmin.Our analysis yields S8=0.762±0.026 and?m=0.234±0.075,with the baryon effects and the intrinsic alignments included.The results are robust against redshift uncertainties.We check the consistency of our results by deriving the cosmological constraints from auto-correlations ofγ1andγ2separately,and find that they are consistent with each other,but the constraints from theγ1component are much weaker than that fromγ2.It implies a much worse data quality ofγ1,which is likely due to additional shear uncertainties caused by CCD electronics(according to the survey strategy of DECa LS).We also perform a pure 2D analysis,which gives S8=0.81_(-0.04)~(+0.03)and?m=0.25_(-0.05)~(+0.06).Our findings demonstrate the potential of the PDF-SYM method for precision cosmology.

关键词： weak lensing shear-shear correlations cosmological parameters observations analysis

Anti-saturation fault-tolerant adaptive torsional vibration control with fixed-time prescribed performance for rolling mill main drive system

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Journal of Iron and Steel Research(International) 2024年第3期31卷 660-669页

作者： Shuang liu Chen Du cong Zhang Zhen-hua Bai Key Lab of Industrial Computer Control Engineering of Hebei Province Yanshan UniversityQinhuangdao 066004HebeiChina National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan UniversityQinhuangdao 066004HebeiChina

An anti-saturation fault-tolerant adaptive torsional vibration control method with fixed-time prescribed performance for the rolling mill main drive system(RMMDS)was investigated,which is affected by control input saturation,actuator faults,sensor measurement errors,and parameter perturbations.First,we gave a continuously differentiable saturation function to approximate the control input saturation characteristic of the RMMDS,translating the saturation characteristic into the matched uncertainty and unknown time-varying gain in the system.Then,an RMMDS mathematical model with unmatched uncertainty and unknown time-varying gain was developed,taking into account the presence of control input saturation,actuator faults,sensor measurement errors,and parameter perturbations.Based on the established mathematical model,an error transformation model of the roll speed tracking was constructed by the equivalent error transformation method.According to the error transformation model,a barrier Lyapunov function and a novel adaptive controller were studied to ensure that the roll speed tracking error always evolves inside a fixed-time asymmetric constraint.Finally,numerical simulations were performed in Matlab/Simulink to verify the effectiveness and superiority of the proposed control method in suppressing the RMMDS torsional vibration.

关键词： Fixed-time prescribed performance Control input saturation Actuator fault Unknown time-varying gain Adaptive control Asymmetric constraint

Ferromagnetism and insulating behavior with a logarithmic temperature dependence of resistivity in Pb_(10-x)Cux(PO_(4))_(6)O

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Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 106-111页

作者： Yuhang Zhang cong liu Xiyu Zhu Hai-Hu Wen Center for Superconducting Physics and Materials National Laboratory of Solid State Microstructures and Department of PhysicsNational Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China

Recent claim of discovering above-room-temperature superconductivity(Tc≈400 K)at ambient pressure in copper doped apatite Pb10(PO_(4))_(6)O has stimulated world-wide enthusiasm and impulse of motion.A lot of follow-up works have been carried out with controversial conclusions.To check whether superconductivity is really present or absent in the material,we need samples which should have a rather pure phase of Pb_(10-x)Cux(PO_(4))_(6)O.Here we report the characterization results from the Pb_(10-x)Cux(PO_(4))_(6)O with a fraction of about 97 wt.%inferred from the fitting to the X-ray diffraction pattern,if assuming Cu2S as the only impurity.The resistivity measurements show that it is a semiconductor characterized roughly by a ln(1/T)temperature dependence in wide temperature region without trace of superconductivity.Magnetization measurements show that it has a general ferromagnetic signal with a weak superparamagnetic background.Many grains of the sample show clear interactions with a Nb Fe B magnet.The detected Cu concentration is much lower than the expected nominal one.Our results show the absence of metallicity and superconductivity in Pb_(10-x)Cux(PO_(4))_(6)O at ambient pressure,and suggest the presence of strong correlation effect.

关键词： superconductivity Pb10(PO4)6O ferromagnetic correlation effect

Global burden of vision loss attributable to household air pollution from 1990 to 2019: A trend analysis and 10-year prediction

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中华医学杂志(英文版) 2024年第10期137卷 2024 Apr 12页

作者： Li cong Jing Zuoqian Shen Jianbo liu Shunming liu Lei Yang Xiaohong Yu Honghua Department of Ophthalmology Guangdong Eye Institute Guangdong Provincial People’s Hospital (Guangdong Academy of Medical Sciences) Southern Medical University Guangzhou Guangdong China School of Medicine South China University of Technology Guangzhou China Department of Ophthalmology The First Hospital of China Medical University Shenyang Liaoning China Department of Neurosurgery Jincheng People’s Hospital Jincheng Shanxi China Guangdong Provincial Key Laboratory of Artificial Intelligence in Medical Image Analysis and Application Guangzhou China

Analysis on influencing factors of detecting chemical oxygen demand in water by three-dimensional spectroscopy

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Optoelectronics Letters 2024年第1期20卷 42-47页

作者： ZHOU Kunpeng liu Zhiyang cong Menglong MAN Shanxin Inner Mongolia Autonomous Region Joint Laboratory of Nuclear and Radiation Detection College of Physics and Electronic InformationInner Mongolia Minzu UniversityTongliao 028000China College of Information Engineering Jingzhou UniversityJingzhou 434000China Alxa League Meteorological Bureau Alxa 750300China

This paper focuses on the standard chemical oxygen demand(COD)liquid and studies the impact of pH,nitrite nitrogen,nitrate nitrogen,heavy metals,salinity,and other factors on fluorescence intensity and fluorescence peak positions during the detection of COD in water using fluorescence spectrometry.The influence mechanisms of different environmental factors on fluorescence spectra are also analyzed.Results indicate that pH value affects the fluorescence emission wavelength(Em),resulting in a red shift from 1.5 to 7.2,and a blue shift from 7.2 to 12.3.Nitrate nitrogen can react with organic matter in water to form nitro compounds,leading to a decrease in fluorescence intensity.Salinity has a negligible effect on T1 peak but a relatively large effect on T2 peak.Heavy metal ion concentration has a significant impact on T2 peak,while T1 peak position shifts with an increase in heavy metal ions.This study aims to explore the factors that can impact the detection of COD in water using three-dimensional fluorescence spectrometry,providing references to improve accuracy and practicability for COD detection based on three-dimensional fluorescence spectrometry.

关键词： chemical negligible nitrate

OsDA1 positively regulates grain width in rice

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The Crop Journal 2024年第1期12卷 92-101页

作者： cong Li Jun liu Liya Zhang Tao Li Hongyu Li Bin liu Tao Zhao Institute of Crop Sciences Chinese Academy of Agricultural SciencesBeijing 100081China Institute of Nanfan&Seed Industry Guangdong Academy of SciencesGuangzhou 510316GuangdongChina

The size and shape of rice grains influence their yield and commercial value.We investigated the role of OsDA1,a rice homolog of the Arabidopsis DA1 gene,in regulating grain size and shape.OsDA1 was highly expressed in young spikelets and glumes.Its overexpression led to enlarged seeds with increased width and decreased length/width ratio(LWR)and knocking out OsDA1 reduced grain width and increased grain length and LWR.A R310K point mutation in the DA1-like domain is a potential target for breeding for increased grain width and length.OsDA1 interacted with TCP gene-family proteins to regulate grain size and shape.Our findings deepen our understanding of the molecular mechanisms underlying grain size regulation and provide useful information for improving grain yield.

关键词： Rice Osda1 Grain size Grain shape Grain length/width ratio TCP

Fuzzing:Progress,Challenges,and Perspectives

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Computers, Materials & Continua 2024年第1期78卷 1-29页

作者： Zhenhua Yu Zhengqi liu Xuya cong Xiaobo Li Li Yin Institute of Systems Security and Control College of Computer Science and TechnologyXi'an University of Science and TechnologyXi'an710054China School of Mathematics and Information Science Baoji University of Arts and SciencesBaoji721013China Institute of Systems Engineering Macao University of Science and TechnologyTaipaMacaoChina

As one of the most effective techniques for finding software vulnerabilities,fuzzing has become a hot topic in software security.It feeds potentially syntactically or semantically malformed test data to a target program to mine vulnerabilities and crash the system.In recent years,considerable efforts have been dedicated by researchers and practitioners towards improving fuzzing,so there aremore and more methods and forms,whichmake it difficult to have a comprehensive understanding of the technique.This paper conducts a thorough survey of fuzzing,focusing on its general process,classification,common application scenarios,and some state-of-the-art techniques that have been introduced to improve its performance.Finally,this paper puts forward key research challenges and proposes possible future research directions that may provide new insights for researchers.

关键词： Fuzzing vulnerability software testing software security