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Modeling and Validation of Diamagnetic Rotor Levitated by Permanent Magnetics

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 224-235页

作者： Yuanping Xu Yue zhang jin Zhou Chaowu jin College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

As an innovative,low-power consuming,and low-stiffness suspension approach,the diamagnetic levitation technique has attracted considerable interest because of its potential applicability in miniaturized mechanical *** foundation of a diamagnetic levitation system is mathematical modeling,which is essential for operating performance optimization and stability ***,few studies on systematic mathematical modeling have been *** this study,a systematic mathematical model for a disc-shaped diamagnetically levitated rotor on a permanent magnet array is *** on the proposed model,the magnetic field distribution characteristics,diamagnetic levitation force characteristics(i.e.,levitation height and stiffness),and optimized theoretical conditions for realizing stable levitation are *** are conducted to verify the feasibility of the proposed mathematical *** predictions and experimental results indicate that increasing the levitation height enlarges the stable ***,with a further increase in the rotor radius,the stable regions of the rotor gradually diminish and even ***,when the levitation height is fixed,a moderate rotor radius permits stable *** study proposes a mathematical modeling method for a diamagnetic levitation system that has potential applications in miniaturized mechanical systems.

关键词： Diamagnetic levitation Magnetic levitation Rotor Modeling Validation Stability

The Effect of Blending Ratio on the Structure and Properties of the PPR/PS In situ Fiber Reinforced System Prepared by Multi-Flow Vibration Injection Molding

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Chinese Journal of Polymer Science 2024年第6期42卷 851-863页

作者： Yan-Jiang Li Meng-long Hu Jun-Wen zhang Qiang Fu Jie zhang College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu610065China

To enhance the mechanical properties of polypropylene random copolymer(PPR),polystyrene(PS)with four different contents were added to the PPR matrix through melt ***,using the Multi-Flow Vibration Injection Molding(MFVIM)technology,PPR/PS in situ microfiber composites(MFC)with different blending ratios were *** results indicated that blending ratio had a great impact on the phase morphology and crystal structure of MFVIM samples,which was different from those of conventional injection molding(CIM)*** ultrafine fibers could be formed under the shear field and could absorb the PPR molecular chains to form hybrid shish-kebab ***,the PPR matrix could also form shish-kebab structures under the effect of strong *** the PS content reached 20%,under the combined action of PS in situ microfibers and highly oriented crystal structure,the tensile strength and Young’s modulus of the sample were obviously improved and the impact strength remained at a relatively high *** a strong and tough balanced PPR based material was *** results provide valuable insights for expanding the industrial and daily-life applications of PPR and show promising development prospects.

关键词： PPR MFVIM In situ microfibers Shearfield Hybrid shish-kebab structures

Deep Video Harmonization by Improving Spatial-temporal Consistency

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Machine Intelligence Research 2024年第1期21卷 46-54页

作者： Xiuwen Chen Li Fang long Ye Qin zhang Key Laboratory of Media Audio and Video Ministry of Education Communication University of ChinaBeijing 100024China

Video harmonization is an important step in video editing to achieve visual consistency by adjusting foreground appear-ances in both spatial and temporal *** methods always only harmonize on a single scale or ignore the inaccuracy of flow estimation,which leads to limited harmonization *** this work,we propose a novel architecture for video harmoniza-tion by making full use of spatiotemporal features and yield temporally consistent harmonized *** introduce multiscale harmon-ization by using nonlocal similarity on each scale to make the foreground more consistent with the *** also propose a fore-ground temporal aggregator to dynamically aggregate neighboring frames at the feature level to alleviate the effect of inaccurate estim-ated flow and ensure temporal *** experimental results demonstrate the superiority of our method over other state-of-the-art methods in both quantitative and visual comparisons.

关键词： Harmonization temporal consistency video editing video composition nonlocal similarity

Multiscale Simulation of Microstructure Evolution during Preparation and Service Processes of Physical Vapor Deposited c-TiAlN Coatings

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Computers, Materials & Continua 2024年第6期79卷 3435-3453页

作者： Yehao long jing Zhong Tongdi zhang Li Chen Lijun zhang State Key Laboratory of Powder Metallurgy Central South UniversityChangsha410083China

Physical Vapor Deposited(PVD)TiAlN coatings are extensively utilized as protective layers for cutting tools,renowned for their excellent comprehensive *** optimize quality control of TiAlN coatings for cutting tools,a multi-scale simulation approach is proposed that encompasses the microstructure evolution of coatings considering the entire preparation and service lifecycle of PVD TiAlN *** scheme employs phase-field simulation to capture the essential microstructure of the PVD-prepared TiAlN ***,cutting simulation is used to determine the service temperature experienced during cutting processes at varying ***-Hilliard modeling is finally utilized to consume the microstructure and service condition data to acquaint the microstructure evolution of TiAlN coatings throughout the cutting *** methodology effectively establishes a correlation between service temperature and its impact on the microstructure evolution of TiAlN *** is expected that the present multi-scale numerical simulation approach will provide innovative strategies for assisting property design and lifespan prediction of TiAlN coatings.

关键词： Multiscale phase-field TiAlN coatings PVD cutting

Small temporal variation in abundance of virioplankton compared to bacterioplankton and phytoplankton in two bays in the northern South China Sea

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Journal of Oceanology and Limnology 2024年第4期42卷 1130-1142页

作者： Jiandong zhang Yineng LI Lijuan long Sijun HUANG CAS Key Laboratory of Tropical Marine Bio-resources and Ecology South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China Marine Environmental Engineering Center South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China Guangdong Provincial Observation and Research Station for Coastal Upwelling Ecosystem South China Sea Institute of OceanologyChinese Academy of SciencesShantou 515041China

Variations of picoplankton groups were investigated over a one-month period in Daya Bay and Sanya Bay,in the northern South China *** two coastal regions exhibited different variation patterns in physicochemical ***,the diel variations of picoplankton groups were different between the two *** abundance of the picoplankton in Sanya Bay displayed a pronounced diel variation,while it was not significant in Daya *** addition,some similar patterns of picoplankton abundance were *** the two bays,virioplankton exhibited the smallest fluctuation range,whereas picocyanobacteria fluctuated most *** fluctuation range of picoplankton groups was larger in spring tide than in neap tide,especially in Sanya *** forest model analysis demonstrated that the variation of picoplankton groups was attributed to physical and chemical factors in Sanya Bay and Daya Bay,***,our findings suggest that virioplankton abundance can persist more stably in response to changing environmental conditions compared to bacterioplankton and picophytoplankton.

关键词： diel variation abundance picoplankton group virioplankton picocyanobacteria

Mobility of rhenium and selenium during chemical weathering and their implication for petrogenic organic carbon oxidation

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Science China Earth Sciences 2024年第3期67卷 740-750页

作者： Yuhong zhang jin WANG Yuanxin QU Chao ZHU zhangdong jin State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an 710061China University of Chinese Academy of Sciences Beijing 100049China Xi'an Institute for Innovative Earth Environment Research Xi'an 710061China Institute of Global Environmental Change Xi'an Jiaotong UniversityXi'an 710049China

The oxidative weathering of petrogenic organic carbon(OC_(petro)) is an important source of carbon dioxide(CO_(2)) into the atmosphere on geological timescales and significantly influences the carbon cycle and global climate change. However, at present, a robust proxy to assess OC_(petro)oxidation is lacking. Riverine rhenium(Re) has emerged as a potential proxy to trace OC_(petro)oxidation, but little is known about Re sources and its relationship with OC_(petro)oxidation. To better understand the robustness of this proxy, we analyzed a shale weathering profile from the early Cambrian Shuijingtuo Formation in Chengkou County, Chongqing City, to address the mobility of Re and selenium(Se) and their relationship with the oxidation of OC_(petro)by analyses of the elemental variation and sequential extraction. The results showed that the chemical index of alteration(CIA)increases from the fresh bedrock to the weathered sections, indicating enhanced weathering intensity. Based on the sequential extraction and mass transfer coefficients(τ), Re and Se mainly exist in the organic phase of shale and are paired lost with OC_(petro) during weathering, with no obvious correlation with sulfide minerals. Furthermore, the different proportions of Re and Se loss with OC_(petro) loss can be attributed to their different geochemical behaviors during weathering. Our study supports Re as a robust proxy to trace OC_(petro) oxidation, whereas Se is the potential one. In the future, combined studies on various sedimentary rock profiles with catchment basins are needed to determine the sources of riverine Re and Se and their relationships with OC_(petro) oxidation.

关键词： Rhenium and selenium Shale Mobility OC_(petro) Chemical weathering

A report of a new late toxic effect of lenvatinib

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Chinese Medical Journal 2020年第6期133卷 747-748页

作者： Bing Yuan jin-long zhang Mao-Qiang Wang Yan Wang Jie-Yu Yan Xiu-Qi Wang jin-Xin Fu Department of Interventional Radiology the General Hospital of People's Liberation ArmyBeijing 100853China

To the Editor:Hepatocellular carcinoma(HCC)is the third most lethal malignancy globally.[1]Besides sorafenib,lenvatinib is currently the second approved targeted agent for the first-line treatment of HCC in *** is an oral multikinase inhibitor that targets vascular endothelial growth factor(VEGF)receptors 1 to 3,fibroblast growth factor receptors 1 to 4,platelet-derived growth factor receptor a,RET,and KIT.[2]Patients who received lenvatinib experienced diarrhoea,and alope and more instances of hypertension,proteinuria,and ***,we report two patients that developed irreversible pancreatic atrophy as a novel adverse event of lenvatinib.

关键词： atrophy targeted irreversible

Sparse representation scheme with enhanced medium pixel intensity for face recognition

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CAAI Transactions on Intelligence Technology 2024年第1期9卷 116-127页

作者： Xuexue zhang Yongjun zhang Zewei Wang Wei long Weihao Gao Bob zhang State Key Laboratory of Public Big Data Institute for Artificial IntelligenceCollege of Computer Science and TechnologyGuizhou UniversityGuiyangGuizhouChina Department of Computer and Information Science University of MacaoAvenida da UniversidadeTaipaMacaoChina

Sparse representation is an effective data classification algorithm that depends on the known training samples to categorise the test *** has been widely used in various image classification *** in sparse representation means that only a few of instances selected from all training samples can effectively convey the essential class-specific information of the test sample,which is very important for *** deformable images such as human faces,pixels at the same location of different images of the same subject usually have different ***,extracting features and correctly classifying such deformable objects is very ***,the lighting,attitude and occlusion cause more *** the problems and challenges listed above,a novel image representation and classification algorithm is ***,the authors’algorithm generates virtual samples by a non-linear variation *** method can effectively extract the low-frequency information of space-domain features of the original image,which is very useful for representing deformable *** combination of the original and virtual samples is more beneficial to improve the clas-sification performance and robustness of the ***,the authors’algorithm calculates the expression coefficients of the original and virtual samples separately using the sparse representation principle and obtains the final score by a designed efficient score fusion *** weighting coefficients in the score fusion scheme are set entirely ***,the algorithm classifies the samples based on the final *** experimental results show that our method performs better classification than conventional sparse representation algorithms.

关键词： computer vision face recognition image classification image representation

FPGA implementation of 500-MHz high-count-rate high-time-resolution real-time digital neutron-gamma discrimination for fast liquid detectors

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Nuclear Science and Techniques 2024年第8期35卷 101-113页

作者： Hui‑Yin Shen jing‑long zhang Jie zhang Jian‑Hang Zhou College of Nuclear Technology and Automation Engineering Chengdu University of TechnologyChengdu 610059China Southwestern Institute of Physics P.O.Box 432Chengdu 610041China

Fast neutron flux measurements with high count rates and high time resolution have important applications in equipment such as *** this study,real-time neutron and gamma discrimination was implemented on a self-developed 500-Msps,12-bit digitizer,and the neutron and gamma spectra were calculated directly on an FPGA.A fast neutron flux measurement system with BC-501A and EJ-309 liquid scintillator detectors was developed and a fast neutron measurement experiment was successfully performed on the HL-2 M tokamak at the Southwestern Institute of Physics,*** experimental results demonstrated that the system obtained the neutron and gamma spectra with a time accuracy of 1 *** count rates of up to 1 Mcps,the figure of merit was greater than 1.05 for energies between 50 keV and 2.8 MeV.

关键词： Neutron-gamma discrimination Liquid scintillation detector Real-time spectrum analyzer