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Computer vision-aided DEM study on the compaction characteristics of graded subgrade filler considering realistic coarse particle shapes

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Railway Engineering Science 2024年第2期32卷 194-210页

作者： Taifeng li Kang Xie xiaobin Chen Zhixing Deng Qian Su Railway Engineering Research Institute China Academy of Railway Sciences Corporation LimitedBeijing 100081China Department of Civil Engineering Central South UniversityChangsha 410075China School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China

The compaction quality of subgrade filler strongly affects subgrade settlement.The main objective of this research is to analyze the macro-and micro-mechanical compaction characteristics of subgrade filler based on the real shape of coarse particles.First,an improved Viola-Jones algorithm is employed to establish a digitalized 2D particle database for coarse particle shape evaluation and discrete modeling purposes of subgrade filler.Shape indexes of 2D subgrade filler are then computed and statistically analyzed.Finally,numerical simulations are performed to quantitatively investigate the effects of the aspect ratio(AR)and interparticle friction coefficient(μ)on the macro-and micro-mechanical compaction characteristics of subgrade filler based on the discrete element method(DEM).The results show that with the increasing AR,the coarse particles are narrower,leading to the increasing movement of fine particles during compaction,which indicates that it is difficult for slender coarse particles to inhibit the migration of fine particles.Moreover,the average displacement of particles is strongly influenced by the AR,indicating that their occlusion under power relies on particle shapes.The dis-placement and velocity of fine particles are much greater than those of the coarse particles,which shows that compaction is primarily a migration of fine particles.Under the cyclic load,the interparticle friction coefficientμhas little effect on the internal structure of the sample;under the quasi-static loads,however,the increase inμwill lead to a significant increase in the porosity of the sample.This study could not only provide a novel approach to investigate the compaction mechanism but also establish a new theoretical basis for the evaluation of intelligent subgrade compaction.

关键词： Subgrade filler particles Deep learning particle Shape analysis Particle library Compaction characteristics Discrete element method(DEM)

Green Synthesis of Iron(Ⅱ,Ⅲ)-polyphenol Nanoparticles and Their Adsorption of Malachite Green

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Journal of Wuhan University of Technology(Materials Science) 2024年第4期39卷 1025-1030页

作者：胡玉 ZHOU Fan ZHANG Nan PAN xiaobin li Shiying ZHANG Dong li li 张玲帆 Department of Chemistry and Environmental Engineering Hanjiang Normal UniversityShiyan 442000China Shiyan Hydrological and Water Resources Survey Bureau of Hubei Province Shiyan 442000China School of Chemistry and Molecular Engineering East China University of Science and TechnologyShanghai 200237China

Three kinds of iron nanoparticles(FeNPs)were prepared via green route based on pomegranate(PG),green tea(GT),and mulberry(ML)extracts under ambient conditions.The obtained materials were characterized by scanning electron microscopy(SEM),transmission electronic microscopy(TEM),X-ray energy-dispersive spectrometer(EDS),X-ray diffraction(XRD),fourier transform infrared spectroscopy(FTIR),and X-ray photoelectron spectroscopy(XPS)techniques.The experimental results show that FeNPs were in the form of amorphous iron(Ⅱ,Ⅲ)-polyphenol complex with different dispersity and morphologies.GT-Fe has the smallest size range of 25-35 nm,PG-Fe has a moderate size-distribution of 30-40 nm,while ML-Fe formed a tuberous net-type with a sheeting structure.PG-Fe displays the highest removal efficiency of 90.2%in 20 min towards cationic dye of malachite green(16.6%by ML-Fe and 69.3%by GT-Fe),which is attributed to its highest polyphenol content,lowest zeta potential,as well as the most Fe^(2+)on the surface of FeNPs.The removal mechanism was mainly induced by electrostatic adsorption based on pH and zeta potential tests.

关键词： iron nanoparticles pomegranate green tea mulberry adsorption

Construction of plum-branch-like CoSe2@N-Doped carbon/carbon fiber with dual protective mechanisms for enhanced lithium storage

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Progress in Natural Science:Materials International 2024年第3期34卷 495-502页

作者： Ying Wang Ming Zhang Lei Chen Yanjuan li Qingqing Wang xiaobin Wu lingdi Shen Xiao Yan School of Chemistry & Materials Science Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials Jiangsu Normal University

Cobalt selenide（CoSe2） emerges as a highly promising anode material for lithium-ion batteries（liBs） owing to its high theoretical capacity and cost-effectiveness. Despite these merits, its practical utilization faces challenges stemming from substantial volume fluctuations and limited electronic conductivity. To tackle these issues, a plumbranch-like structure of CoSe2@N-doped carbon that embedded in one-dimensional N-doped carbon fibers（CoSe2@NC/CFs）, is successfully synthesized through an in-situ confinement method. Well-defined CoSe2@NC nanoparticles, featuring diameters between 20～30 nm, are uniformly dispersed on both the inner and outer surfaces of the carbon fibers. The distinctive architecture of CoSe2@NC/CFs ensures an increased number of active sites, elevated electronic conductivity, alleviated volume expansion, and accelerated reaction kinetics.Consequently, the CoSe2@NC/CFs exhibits remarkable cycling performance and exceptional rate capability.Operating at a current density of 1000 mA g-1, the CoSe2@NC/CFs anode sustains a capacity of 664 mA h g-1with no obvious capacity decay over 500 cycles. Even at a high current density of 5000 mA g-1, it maintains a capacity of 445 mA h g-1with a mere 0.02 % capacity decay per cycle. This study introduces a novel approach to anode material design, showcasing significant advancements in lithium-ion battery technology.

关键词： Carbon fiber Electrochemical performances Electrode lithium-ion battery Metal-selenide

Photometric Analysis for Asteroid (81) Terpsichore using Convex Inversion and Phase Function Fitting Methods

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Research in Astronomy and Astrophysics 2024年第6期24卷 203-210页

作者： Ao Wang xiaobin Wang Xiaoyun Xu Longhua Qin Quangui Gao Huaizhen li Yong Xiao Hairu Zhao Department of Physics Yuxi Normal University Yunnan Observatories Chinese Academy of Sciences Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences University of Chinese Academy of Sciences

The shapes and rotation states（periods and pole orientations） of main-belt asteroids are important for understanding their formation and evolution. In order to obtain sufficient photometric data covering different apparitions for asteroid （81） Terpsichore, ground-based photometric observations in 2020 and 2021 were carried out. By combining published and newly obtained photometric data, we calculated the shape and spin parameters for （81） Terpsichore using the convex inversion method. With this method, we have derived a best fitted pole orientation—(22.2±3.13.3°, 17.5±5.510.8°) with a spin period of 10.94 ±0.010.01h. Based on the derived convex shape of （81） Terpsichore, we have fitted the H, G+1, G2phase function using the calibrated TESS data and Gaia data after accounting for the lightcurve amplitude correction. As a result, we have derived its absolute magnitude H = 8.68 ±0.190.22mag with corresponding phase function parameters G1= 0.82 ±0.100.09and G2= 0.02±0.020.03.

关键词： asteroids: general asteroids: individual (Terpsichore) minor planets techniques: photometric

Bimolecular reduction of carbon dioxide: double synthons for alkynes trifunctionalization

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Science China Chemistry 2024年第3期67卷 841-847页

作者： Wenfang Xiong xiaobin Tan Hongjian liu Baiyao Zhu Jinwu Zhao Jianxiao li Chaorong Qi Huanfeng Jiang School of Pharmacy Guangdong Medical UniversityDongguan 523808China Key Lab of Functional Molecular Engineering of Guangdong Province School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China

Carbon dioxide reduction, as a sustainable and versatile strategy for the access of chemical fuels, has attracted increasing attention and enormous efforts have been devoted to it in recent years. However, employing carbon dioxide as double synthons via bimolecular reduction remains challenging. Here, by leveraging the bimolecular reduction of carbon dioxide to carbonyl and methyl respectively, we describe a Pd-catalyzed trifunctionalization of alkynes with aryl iodide for the first time and showcase its advantages on the formation of various β-diketones and their application in the constructing of heterocyclic compounds with important biological activity, including pyrimidine, oxazole, pyrazole.

关键词： carbon dioxide bimolecular reduction trifunctionalization double synthons

Unsupervised hyperspectral unmixing based on robust nonnegative dictionary learning

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Journal of Systems Engineering and Electronics 2022年第2期33卷 294-304页

作者： li Yang JIANG Bitao li xiaobin TIAN Jing SONG Xiaorui Department of Space Information Space Engineering UniversityBeijing 101400China Beijing Institute of Remote Sensing Information Beijing 100192China

Considering the sparsity of hyperspectral images(HSIs),dictionary learning frameworks have been widely used in the field of unsupervised spectral unmixing.However,it is worth mentioning here that existing dictionary learning method-based unmixing methods are found to be short of robustness in noisy contexts.To improve the performance,this study specifically puts forward a new unsupervised spectral unmixing solution.For the reason that the solution only functions in a condition that both endmembers and the abundances meet non-negative con-straints,a model is built to solve the unsupervised spectral un-mixing problem on the account of the dictionary learning me-thod.To raise the screening accuracy of final members,a new form of the target function is introduced into dictionary learning practice,which is conducive to the growing robustness of noisy HSI statistics.Then,by introducing the total variation(TV)terms into the proposed spectral unmixing based on robust nonnega-tive dictionary learning(RNDLSU),the context information under HSI space is to be cited as prior knowledge to compute the abundances when performing sparse unmixing operations.Ac-cording to the final results of the experiment,this method makes favorable performance under varying noise conditions,which is especially true under low signal to noise conditions.

关键词： hyperspectral image(HSI) nonnegative dictionary learning norm loss function unsupervised unmixing

Enhancing Photovoltaic Performance of Nonfused-Ring Electron Acceptors via Asymmetric End-Group Engineering and Noncovalently Conformational Locks

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Chinese Journal of Chemistry 2024年第5期42卷 485-490页

作者： Bo liu Congqi li xiaobin Gu Yinghui Han Zhixiang Wei Yunhao Cai Xin Zhang Hui Huang Yanping Huo School of Chemical Engineering and light Industry Guangdong University of TechnologyGuangzhouGuangdong510006 China College of Materials Science and Opto-Electronic Technology & Center of Materials Science and Optoelectronics Engineering & CAS Center for Excellence in Topological Quantum Computation & CAS Key Laboratory of Vacuum Physics University of Chinese Academy of SciencesBeijing100049 China College Resources and Environment University of Chinese Academy of SciencesBeijing100049 China Center for Excellence in Nanoscience (CAS) & Key Laboratory of Nanosystem and Hierarchical Fabrication (CAS) National Center for Nanoscience and TechnologyBeijing100190 China

By employing the asymmetric end-group engineering,an asymmetric nonfused-ring electron acceptor(NFREA)was designed and synthesized.Compared with the symmetric analogs(NoCA-17 and NoCA-18),NoCA-19 possesses broader light absorption range,more coplanarπ-conjugated backbone,and appropriate crystallinity according to the experimental and theoretical results.The organic solar cells based on J52:NoCA-19 exhibited a power conversion efficiency as high as 12.26%,which is much higher than those of J52:NoCA-17(9.50%)and J52:NoCA-18(11.77%),mainly due to more efficient exciton dissociation,better and balanced charge mobility,suppressed recombination loss,shorter charge extraction time,longer charge carrier lifetimes,and more favorable blend film morphology.These findings demonstrate the great potential of asymmetric end-group engineering in exploring low-cost and high-performance NFREAs.

关键词： Organic solar cells Nonfused-ring electron acceptors Asymmetric end-group engineering Noncovalently conformational locks Low-cost acceptors

Non-radical activation of persulfate with Bi_(2)O_(3)/BiO_(1.3)I_(0.4)for efficient degradation of propranolol under visible light

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Journal of Environmental Sciences 2024年第8期142卷 57-68页

作者： Yuehua Deng Qianqian Che Yani li Jiating Luo Xiang Gao Yan He Yiling liu Tong liu Xiaolong Zhao xiaobin Hu Wei Zhao College of Geology and Environment Xi’an University of Science and TechnologyXi’an 710054China Shaanxi Provincial Key Laboratory of Geological Support for Coal Green Exploitation Xi’an 710054China Department of Mechanical Engineering The University of Hong KongHong Kong 999077China School of life Science Huzhou UniversityHuzhou 313000China School of Materials Engineering Changshu Institute of TechnologyChangshu 215500China

Non-radical activation of persulfate(PS)by photocatalysts is an effective approach for removing organic pollutants from aqueous environments.In this study,a novel Bi_(2)O_(3)/BiO_(1.3)I_(0.4)heterojunction was synthesized using a facile solvothermal approach and used for the first time for non-radical activation of PS to degrade propranolol(PRO)in the presence of visible light.The findings found that the degradation rate of PRO in the Bi_(2)O_(3)/BiO_(1.3)I_(0.4)/PS system was significantly increased from 19%to more than 90%within 90 min compared to the Bi_(2)O_(3)/BiO_(1.3)I_(0.4)system.This indicated that the composite system exerted an excellent synergistic effect between the photocatalyst and the persulfate-based oxygenation.Quenching tests and electron paramagnetic resonance demonstrated that the non-radical pathway with singlet oxygen as the active species played a major role in the photocatalytic process.The existence of photo-generated holes during the reaction could also be directly involved in the oxidation of pollutants.Meanwhile,a possible PRO degradation pathway was also proposed.Furthermore,the impacts of pH,humic acid and common anions on the PRO degradation by the Bi_(2)O_(3)/BiO_(1.3)I_(0.4)/PS were explored,and the system’s stability and reusability were also studied.This study exhibits a highly productive catalyst for PS activation via a non-radical pathway and provides a new idea for the degradation of PRO.

关键词： Iodine deficiency Heterojunction Persulfate(PS) Propranolol(PRO) Photocatalytic degradation

Development and prospect of telemedicine

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Intelligent Medicine 2024年第1期4卷 1-9页

作者： Zhiyue Su Chengquan li Haitian Fu liyang Wang Meilong Wu xiaobin Feng University College London LondonWC1E 6BTUnited Kingdom School of Clinical Medicine Tsinghua UniversityBeijing 100084China Division of Hepatobiliary and Pancreas Surgery Department of General SurgeryShenzhen People’s Hospital(The Second Clinical Medical College of Jinan UniversityThe First Affiliated Hospital of Southern University of Science and Technology)ShenzhenGuangdong 518020China

With the continuous improvement and development of modern network information technology and the continuous improvement of people’s demands for health care,the traditional health care model has evolved,giving birth to a new telemedicine health care model.Telemedicine refers to the comprehensive application of information technology for medical information transmission and long-distance communication between different places.It integrates medicine,computer technology,and communication technology for remote monitoring,diagnosis,consultation,case discussion,teaching,and surgery as well as a series of medical activities.With the continuous development of communication technology,telemedicine is also constantly changing.As a relatively novel technology,telemedicine is sought after by major hospitals.With the advancement of internet technology,digitization and informatization have been gradually applied in telemedicine,but due to various factors,telemedicine still has great limitations.This paper summarized the development status of telemedicine;discussed in detail the development of telemedicine at home and abroad;reviewed the application of telemedicine as well as the feasibility and limitations of its promotion and development;and put forward an outlook for the future development of telemedicine.

关键词： Telemedicine Medical service Application development