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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

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Structural Engineering of Hierarchical Magnetic/Carbon Nanocomposites via In Situ Growth for High-Efficient Electromagnetic Wave Absorption

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Nano-Micro Letters 2024年第9期16卷 262-278页

作者： Xianyuan liu Jinman Zhou Ying xue Xianyong Lu Key Laboratory of Bio‑Inspired Smart Interfacial Science and Technology of Ministry of Education School of ChemistryBeihang UniversityBeijing 100191People’s Republic of China

Materials exhibiting high-performance electromagnetic wave absorption have garnered considerable scientific and technological attention,yet encounter significant challenges.Developing new materials and innovative structural design concepts is crucial for expanding the application field of electromagnetic wave absorption.Particularly,hierarchical structure engineering has emerged as a promising approach to enhance the physical and chemical properties of materials,providing immense potential for creating versatile electromagnetic wave absorption materials.Herein,an exceptional multi-dimensional hierarchical structure was meticulously devised,unleashing the full microwave attenuation capabilities through in situ growth,selfreduction,and multi-heterogeneous interface integration.The hierarchical structure features a three-dimensional carbon framework,where magnetic nanoparticles grow in situ on the carbon skeleton,creating a necklace-like structure.Furthermore,magnetic nanosheets assemble within this framework.Enhanced impedance matching was achieved by precisely adjusting component proportions,and intelligent integration of diverse interfaces bolstered dielectric polarization.The obtain Fe_(3)O_(4)-Fe nanoparticles/carbon nanofibers/Al-Fe_(3)O_(4)-Fe nanosheets composites demonstrated outstanding performance with a minimum reflection loss(RLmin)value of−59.3 dB and an effective absorption bandwidth(RL≤−10 dB)extending up to 5.6 GHz at 2.2 mm.These notable accomplishments offer fresh insights into the precision design of high-efficient electromagnetic wave absorption materials.

关键词： Electromagnetic wave absorption Hierarchical structure In situ growth Self-reduction

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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

Temporal and Spectral Characteristics of Persistent Emission and Special Bursts of Magnetar SGR J1935+2154 Based on Insight-HXMT

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Research in Astronomy and Astrophysics 2024年第6期24卷 227-235页

作者： xue-Feng Lu Li-Ming Song Ming-Yu Ge Shuang-Nan Zhang Jin-Lu Qu Ce Cai cong-Zhan liu Cheng-Kui Li Yu-cong Fu Ying-Chen Xu Key Laboratory of Particle Astrophysics Institute of High Energy Physics University of Chinese Academy of Sciences Chinese Academy of Sciences College of Physics and Hebei Key Laboratory of Photophysics Research and Application Hebei Normal University Department of Astronomy Beijing Normal University

In October 2022, the magnetar SGR J1935+2154 entered the active outburst state. During the episode, the InsightHXMT satellite carried out a long observation that lasted for 20 days. More than 300 bursts were detected, and a certain amount of persistent radiation signals were also accumulated. This paper mainly introduces the results of persistent radiation profile folding and period search based on Insight-HXMT data. At the same time, the burst phase distribution characteristics, spectral lag results of burst, the spectral characteristics of zero-lag bursts and the time-resolved spectral evolution characteristics of high-flux bursts are reported. We found that there is no significant delay feature during different energy bands for the bursts of SGR J1935+2154. The observed zero-lag burst does not have a unique spectrum. The time-resolved spectrum of the individual burst has consistent spectral types and spectral parameters at different time periods of the burst. We also find that the burst number phase distribution and the burst photon phase distribution have the same tendency to concentrate in specific regions of the persistent emission profile.

关键词： dense matter magnetic fields radiation mechanisms: general

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

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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

Development and Evaluation of a Promising Biomarker for Diagnosis of Latent and Active Tuberculosis Infection

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Infectious Diseases & Immunity 2024年第1期4卷 10-24页

作者： cong Peng Fan Jiang Yinping liu Yong xue Peng Cheng Jie Wang Liang Wang Wenping Gong Hebei North University Zhangjiakou 075000Hebei ProvinceChina Beijing Key Laboratory of New Techniques of Tuberculosis Diagnosis and Treatment Senior Department of TuberculosisEighth Medical Center of PLA General HospitalBeijing 100091China Department of Geriatrics Eighth Medical Center of PLA General HospitalBeijing 100091China Section of Health No.94804 Unit of the Chinese People's Liberation ArmyShanghai 200434China

Background:Diagnosing latent tuberculosis(TB)infection(LTBI)and active TB(ATB)is crucial for preventing disease progression and transmission.However,current diagnostic tests have limitations in terms of accuracy and sensitivity,making it challenging to diagnose these different infection states.Therefore,this study intends to develop a promising biomarker for LTBI and ATB diagnosis to overcome the limitations of the current diagnostic tests.Methods:We developed a novelmultiepitope-based diagnostic biomarker(MEBDB)fromLTBI region of differentiation antigens using bioinformatics and immunoinformatics.Immune responses induced byMEBDM were detected using enzyme-linked immunosorbent spot and cytometric bead assays.This study was conducted from April 2022 to December 2022 in the SeniorDepartment of Tuberculosis at the 8thMedical Center of PLA General Hospital,China.Blood samples were collected from participants with ATB,individuals with LTBI,and healthy controls(HCs).The diagnostic efficacy of MEBDB was evaluated using receiver operating characteristic curves.Results:A novel MEBDB,designated as CP19128P,was generated.CP19128P comprises 19 helper T lymphocyte epitopes,12 cytotoxic T lymphocyte epitopes,and 8 B-cell epitopes.In silico simulations demonstrated that CP19128P possesses strong affinity for Toll-like receptors and elicits robust innate and adaptive immune responses.CP19128P generated significantly higher levels of tumor necrosis factor(TNF-α),interleukin 4(IL-4),and IL-10 in ATB patients(n=7)and LTBI(n=8)individuals compared with HCs(n=62)(P<0.001).Moreover,CP19128P-induced specific cytokines could be used to discriminate LTBI and ATB from healthy subjects with high sensitivity and specificity.Combining IL-2 with IL-4 or TNF-α could differentiate LTBI from HCs(the area under the receiver operating characteristic curve[AUC],0.976[95% confidence interval[CI],0.934-1.000]or 0.986[0.956-1.000]),whereas combining IL-4 with IL-17A or TNF-α could differentiate ATB from HCs(AUC,0.887[0.782-0.993]or 0.984[0.958-1.000])

关键词： Tuberculosis Latent tuberculosis infection Active tuberculosis Multiepitope-based diagnostic biomarker Bioinformatics:Immunoinformatics