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Interaction of magnetic spheres in magnetic fields from the view of magnetic energy density:A 3D finite element analysis(FEA)

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International Journal of Mining Science and Technology 2022年第6期32卷 1341-1350页

作者： Jiangang Ku Zhongyun Lei Hua Lin Quanxiang Yan huihuang chen Bao Guo Zijin School of Geology and Mining Fuzhou UniversityFuzhou 350116China State Key Laboratory of Mineral Processing Beijing 100160China College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen 518060China

Magnetic interaction between magnetic particles is of great significance in the fields of magnetic separation and functional materials.A good understanding of interaction mechanism of magnetic particles would further boost its promising industrial applications.We hereby present our work which visualizes the movement behavior of magnetic spheres in magnetic fields employing high-speed imaging and simulates the dynamic behavior of spheres using an Arbitrary Lagrangian-Eulerian(ALE)based on finite element method.In this paper,we investigated the stress tensor,magnetic force,and dynamic behavior of magnetic spheres in magnetic fields,especially magnetic energy density in different domains.Results show that there are four relatively independent regions of magnetic energy density distribution in external spatial domains of a single sphere system.Attractive force will generate when the energy density in the spatial region between two spheres is relatively high,while a repulsive force will generate when the energy density in the spatial region between two spheres is relatively low.Every magnetic sphere spontaneously moves towards the region with high energy density and stays away from the region with low energy density.The total magnetic energy in magnetic spheres’domains(V_(1))and external spatial domains(V_(2))increases,but the magnetic energy in the external spatial domain decreases over time during the aggregation process.The magnetic spheres ultimately arrange in chain-like structures oriented along magnetic field direction.We hereby proposed a novel and efficient approach to predict the movement trends and final state of magnetic particle swarm from the view of energy density.

关键词： Magnetic force Stress tensor Magnetic spheres Interaction 3D FEA

Urbanization reduces resource use efficiency of phytoplankton community by altering the environment and decreasing biodiversity

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Journal of Environmental Sciences 2022年第2期34卷 140-151页

作者： Yigang Yang huihuang chen Mamun Abdullah Al Jean Claude Ndayishimiye Jun R Yang Alain Isabwe Anqi Luo Jun Yang Aquatic EcoHealth Group Fujian Key Laboratory of Watershed EcologyKey Laboratory of Urban Environment and HealthInstitute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China University of Chinese Academy of Sciences Beijing 100049China Engineering Research Center of Ecology and Agricultural Use of Wetland(Ministry of Education) College of AgricultureYangtze UniversityJingzhou 434025China

Urbanization often exerts multiple effects on aquatic and terrestrial organisms,including changes in biodiversity,species composition and ecosystem functions.However,the impacts of urbanization on river phytoplankton in subtropical urbanizing watersheds remain largely unknown.Here,we explored the effects of urbanization on phytoplankton community structure(i.e.,biomass,community composition and diversity)and function(i.e.,resource use efficiency)in a subtropical river at watershed scale in southeast China over 6 years.A total of 318 phytoplankton species belonging into 120 genera and 7 phyla were identified from 108 samples.Bacillariophyta biomass showed an increasing trend with increasing urbanization level.The phytoplankton community shifted from Chlorophyta dominance in rural upstream waters to Bacillariophyta dominance in urbanized downstream waters.Furthermore,phytoplankton diversity and resource use efficiency(RUE=phytoplankton biomass/total phosphorus)were significantly decreased with increasing urbanization level from upstream to downstream.Phytoplankton RUE exhibited a significant positive correlation with species richness,but a negative correlation with phytoplankton evenness.The variation in environmental factors(turbidity,total nitrogen,NH_(4)^(+)-N,total phosphorus,PO_(4)^(3-)-P and percentage urbanized area)was significantly correlated with phytoplankton diversity and RUE.Overall,our results revealed the influence of urbanization on phytoplankton community structure and ecosystem function was due to its altering the environmental conditions.Therefore,human-driven urbanization may play crucial roles in shaping the structure and function of phytoplankton communities in subtropical rivers,and the mechanism of this process can provide important information for freshwater sustainable uses,watershed management and conservation.

关键词： Plankton Community functioning Subtropical river Urbanization gradient Land use Watershed ecology

Effect of unstable resonator stability on laser beam quality

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Optoelectronics Letters 2024年

作者： LIANG Xiaolin BAO Bengang ZHOU Songqing chen huihuang College of Intelligent Manufacturing Hunan University of Science and Engineering

In order to explore the effect of unstable resonator stability on laser beam quality， the numerical simulation of mid-infrared laser and visible laser was carried out in GLAD software. The simulation results showed that the existence of defocus aberration， tilt aberration and astigmatic aberration in the unstable resonator can cause the center of the far-field spot of the output annular beam to drift， the number of peripheral diffraction rings to increase， the beam quality to deteriorate， and the degree of effect is different. It is also found that on the basis of the effect of tilt aberration and astigmatism aberration， the introduction of defocus aberration can improve the output laser beam quality to a certain extent. In addition， under the condition of the same aberrations， the effects of different wavelength lasers are roughly the same. However， in terms of the degree of effects， the short-wave laser is much higher than the medium-long-wave laser， which verifies that the resonator debugging of the short-wave laser is more difficult than that of the medium-long-wave laser in the experimental process. The simulation results can provide an important reference for the optimization design of the laser system， the processing of cavity mirror and the formulation of the correction range index of the adaptive optical system.

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Evolution of the newest diagnostic methods for COVID-19:a Chinese perspective

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2023年第6期24卷 463-484页

作者： Mingtao LIU Jiali LYU Xianhui ZHENG Zhiman LIANG Baoying LEI huihuang chen Yiyin MAI Huimin HUANG Baoqing SUN Department of Clinical Laboratory National Center for Respiratory MedicineNational Clinical Research Center for Respiratory DiseaseState Key Laboratory of Respiratory DiseaseGuangzhou Institute of Respiratory Healththe First Affiliated Hospital of Guangzhou Medical UniversityGuangzhou510140China National Center for Respiratory Medicine National Clinical Research Center of Respiratory DiseaseState Key Laboratory of Respiratory DiseaseGuangzhou Institute of Respiratory Healththe First Affiliated Hospital of Guangzhou Medical UniversityGuangzhou 510140China Guangzhou Medical University Guangzhou 511495China

Coronavirus disease 2019(COVID-19)has continued to spread globally since late 2019,representing a formidable challenge to the world's healthcare systems,wreaking havoc,and spreading rapidly through human contact.With fever,fatigue,and a persistent dry cough being the hallmark symptoms,this disease threatened to destabilize the delicate balance of our global community.Rapid and accurate diagnosis of COVID-19 is a prerequisite for understanding the number of confirmed cases in the world or a region,and an important factor in epidemic assessment and the development of control measures.It also plays a crucial role in ensuring that patients receive the appropriate medical treatment,leading to optimal patient care.Reverse transcription-polymerase chain reaction(RT-PCR)technology is currently the most mature method for detecting viral nucleic acids,but it has many drawbacks.Meanwhile,a variety of COVID-19 detection methods,including molecular biological diagnostic,immunodiagnostic,imaging,and artificial intelligence methods have been developed and applied in clinical practice to meet diverse scenarios and needs.These methods can help clinicians diagnose and treat COVID-19 patients.This review describes the variety of such methods used in China,providing an important reference in the field of the clinical diagnosis of COVID-19.

关键词： Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) Coronavirus disease 2019(COVID-19) Diagnosis Polymerase chain reaction(PCR) Immunoassay Radiography

Directing in-situ self-optimization of single-atom catalysts for improved oxygen evolution

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Journal of Energy Chemistry 2023年第5期80卷 284-290,I0007页

作者： Peiyu Ma chen Feng huihuang chen Jiawei Xue Xinlong Ma Heng Cao Dongdi Wang Ming Zuo Ruyang Wang Xilan Ding Shiming Zhou Zhirong Zhang Jie Zeng Jun Bao Hefei National Research Center for Physical Sciences at the Microscale Key Laboratory of Strongly-Coupled Quantum Matter Physics of Chinese Academy of SciencesKey Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education InstitutesDepartment of Chemical PhysicsUniversity of Science and Technology of ChinaHefei230026AnhuiChina National Synchrotron Radiation Laboratory iChEM(Collaborative Innovation Center of Chemistry for Energy Materials)University of Science and Technology of ChinaHefei 230026AnhuiChina

The demand for clean and sustainable energy has encouraged the production of hydrogen from water electrolyzers.To overcome the obstacle to improving the efficiency of water electrolyzers,it is highly desired to fabricate active electrocatalysts for the sluggish oxygen evolution process.However,there is generally an intrinsic gap between the as-prepared and real electrocatalysts due to structure evolution under the oxidative reaction conditions.Here,we combine in-situ anionic leaching and atomic deposition to realize single-atom catalysts with self-optimized structures.The introduced F ions facilitate structural transformation from Co(OH)xF into CoOOH(F),which generates an amorphous edge surface to provide more anchoring sites for Ir single atoms.Meanwhile,the in-situ anionic leaching of F ions elevates the Co valence state of Ir_(1)/CoOOH(F)more significantly than the counterpart without F ions(Ir_(1)/CoOOH),leading to stronger adsorption of oxygenated intermediates.As revealed by electrochemical measurements,the increased Ir loading together with the favored adsorption of*OH intermediates improve the catalytic activity of Ir_(1)/CoOOH(F).Specifically,Ir_(1)/CoOOH(F)delivered a current density of 10 mA cm-2at an overpotential of 238 mV,being lower than 314 mV for Ir_(1)/CoOOH.The results demonstrated the facility of the in-situ optimization process to optimize catalyst structure for improved performance.

关键词： Electrocatalysis Single-Atom Catalysis Self-Optimization Oxygen Evolution

Improved dark ambient degradation of organic pollutants by cerium strontium cobalt perovskite

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Journal of Environmental Sciences 2020年第4期32卷 110-118页

作者： huihuang chen Julius Motuzas Wayde Martens Joao C.Diniz da Costa The University of Queensland FIM^2 Lab-Functional Interfacial Materials and Membranes LaboratorySchool of Chemical EngineeringBrisbaneQld 4072Australia Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of ChinaAnhui 230026China Science and Engineering Faculty Queensland University of TechnologyBrisbaneQld 4000Australia LAQV-REQUIMTE (Bio)Chemical Process EngineeringDepartment of ChemistryFaculty of Science and TechnologyUniversidade NOVA de LisboaCaparica 2829-516Portugal

This work investigates the effect of cerium substation into strontium cobalt perovskites(CeSrCoO)for the oxidative degradation of OrangeⅡ(OII)in dark ambient conditions without the aid of any external stimulants such as light,heating or chemical additives.The OII degradation rate by CeSrCoO reached 65%in the first hour,whilst for the blank sample without cerium(SrCoO)took over 2 hr to reach the same level of OII degradation.Hence,the cerium substitution improved the catalytic activity of the perovskite material,mainly associated with the Ce0.1Sr0.9CoO3 perovskite phase.Upon contacting CeSrCoO,the-N=Nazo bonds of the OII molecules broke down resulting in electron donation and the formation of by-products.The electrons are injected into the CeSrCoO and resulted in a redox pair of Co3+/Co2+,establishing a bridge for the electron transfer between OII and the catalysts.Concomitantly,the electrons also formed reactive species(·OH)responsible for OII degradation as evidenced by radical trapping experiment.Reactive species were formed via the reaction between 02 and donated electrons from OII with the aid of cobalt redox pair.As the prepared materials dispensed with the need for light irradiation and additional oxidants,it opens a window of environmental applications for treating contaminated wastewaters.

关键词： Dark catalysis Acid orange degradation Cerium substituted perovskite Catalytic activity

Structural and functional variations of phytoplankton communities in the face of multiple disturbances

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Journal of Environmental Sciences 2021年第2期33卷 287-297页

作者： Jun R.Yang Xiaoqing Yu huihuang chen Yi-Ming Kuo Jun Yang Engineering Research Center of Ecology and Agricultural Use of wetland(Ministry of Education)College of Agriculture Yangtze UniversityJingzhou 434025China Aquatic Ecohealth Group Fujian Key Laboratory of Watershed EcologyKey Laboratory of Urban Environment and HealthInstitute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China School of Environmental Studies China University of GeosciencesWuhan 430074China

The global decline of freshwater biodiversity caused by climate change and human activities are supposed to disrupt ecosystem services related to water quality and alter the structure and function of aquatic communities across space and time,yet the effects of the combination of these factors on plankton community ecosystem has received relatively little attention.This study aimed to explore the impacts of disturbances(e.***.human activity,temperature,precipitation,and water level)on phytoplankton community structure(i.***.community evenness and community composition)and function(i.***.resource use efficiency)in four subtropical reservoirs over 7 years from 2010 to 2016.Our results showed that community turnover(measured as community dissimilarity)was positively related to disturbance frequency,but no significant correlation was found between phytoplankton biodiversity(i.***.evenness)and disturbance frequency.Phytoplankton resource use efficiency(RUE=phytoplankton biomass/total phosphorus)was increased with a higher frequency of disturbance with an exception of cyanobacteria.The RUE of Cyanobacteria and diatoms showed significantly negative correlations with their community evenness,while the RUE of Chlorophyta exhibited a positive correlation with their community turnover.We suggest that multiple environmental disturbances may play crucial roles in shaping the structure and functioning of plankton communities in subtropical reservoirs,and mechanism of this process can provide key information for freshwater uses,management and conservation.

关键词： Algae Biodiversity Community ecology Plankton Resource use efficiency Subtropical reservoir

Designing cost-effective network-on-chip by dual-channel access mechanism

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Journal of Systems Engineering and Electronics 2011年第4期22卷 557-564页

作者： Shijun Lin Jianghong Shi huihuang chen Department of Communication Engineering Xiamen University Xiamen 361005 E R. China

A dual-channel access mechanism to overcome the drawback of traditional single-channel access mechanism for network-on-chip （NoC） is proposed. In traditional single-channel access mechanism, every Internet protocol （IP） has only one chan- nel to access the on-chip network. When the network is relatively idle, the injection rate is too small to make good use of the network resource. When the network is relatively busy, the ejection rate is so small that the packets in the network cannot leave immediately, and thus the probability of congestion is increased. In the dual-channel access mechanism, the injection rate of IP and the ejection rate of the network are increased by using two optional channels in network interface （NI） and local port of routers. Therefore, the communication performance is improved. Experimental results show that compared with traditional single-channel access mechanism, the proposed scheme greatly increases the throughput and cuts down the average latency with reasonable area increase.

关键词： network-on-chip （NoC） system-on-chip （SoC） singlechannel access dual-channel access.

Reflectivity measurement technology of special high reflective mirrors and uncertainty analysis of measurement results

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Optoelectronics Letters 2023年第1期19卷 49-54页

作者： LIANG Xiaolin ZHOU Songqing LI Xiaowu ZHOU Ling chen huihuang College of Intelligent Manufacturing Hunan University of Science and EngineeringYongzhou425199China

In order to meet the reflectivity measurement requirements of any incident angle at different points of the large size special high mirror,a rotating cavity ring-down spectroscopy high reflectivity measurement system was built,in which the rotation function of the resonant cavity was set,and the lifting and parallel travelling mechanism of the measured mirror was added.Furthermore,the uncertainty of the measurement results was analyzed and calculated.The results showed that the reflectivity of a high reflective mirror measured by the system was 99.9795%,the measurement accuracy reached the order of 10-6,and the combined standard uncertainty of reflectivity measurement was 0.0028%.Collectively,these results provide a detection guarantee for the maintenance of the large size special high mirror,and provide ideas and methods for the uncertainty analysis of measurement results of similar equipment parameters.

关键词： reflective lifting mirror