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BDS/GPS deformation analysis of a long-span cable-stayed bridge based on colored noise filtering

Geodesy and Geodynamics 2023年第2期14卷 163-171页

作者： JUN MA China Railway Siyuan Survey and Design Group Co. LTDWuhan 430079China School of Surveying and mapping Wuhan UniversityWuhan 430079China

Combining GPS and BDS technology to monitor the deformation of long-span railway bridges with stricter deformation control requirements is of significance to the safety and control of the bridge and the safety of railway traffic.Previous studies have ignored the influence of coloured noise in the deformation time series.This is not conducive to accurate deformation analysis of long-span railway bridges.Therefore,GPS,BDS and GPS/BDS monitoring data of Ganjiang Bridge located in Ganzhou city,Jiangxi Province,China are adopted in this paper to filter the coloured noise in the deformation time series by principal component analysis(PCA),and the influence of coloured noise on the deformation analysis results of railway bridge is analysed.The experimental results show that the diurnal temperature difference causes the mid-span and the tower of the railway cable-stayed bridge to deform with a period of about one day in the vertical and longitudinal directions,respectively.Ignoring colored noise will make the uncertainty of the deformation parameter estimation overly optimistic.PCA can significantly reduce the coloured noise,and thus reduce the uncertainty of deformation parameter estimation by about 73%.Moreover,the average difference between the daily periodic motion amplitudes of the monitoring points obtained by using GPS and BDS deformation time series is 1.65 mm.The use of GPS/BDS deformation time series is not only helpful to reduce the influence of coloured noise,but also can reduce the difference between amplitude analysis results obtained from GPS and BDS deformation time series.

关键词： Long-span railway bridges GNSS deformation monitoring Coloured noise PCA

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Biophysical neurons,energy,and synapse controllability:a review

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第2期24卷 109-129页

作者： JUN MA Department of Physics Lanzhou University of TechnologyLanzhou 730050China School of Science Chongqing University of Posts and TelecommunicationsChongqing 430065China

Diffusive intracellular and extracellular ions induce a gradient electromagnetic field that regulates membrane potential,and energy injection from external stimuli breaks the energy balance between the magnetic and electric fields in a cell.Indeed,any activation of biophysical function and self-adaption of biological neurons may be dependent on energy flow,and synapse connection is controlled to reach energy balance between neurons.When more neurons are clustered and gathered closely,field energy is exchanged and shape formation is induced to achieve local energy balance.As a result,the coexistence of multiple firing modes in neural activities is fostered to prevent the occurrence of bursting synchronization and seizure.In this review,a variety of biophysical neuron models are presented and explained in terms of their physical aspects,and the controllability of functional synapses,formation of heterogeneity,and defects are clarified for knowing the synchronization stability and cooperation between functional regions.These models and findings are summarized to provide new insights into nonlinear physics and computational neuroscience.

关键词： Energy balance Creation of synapse Functional neuron Heterogeneity Defects

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Bio-Adaption between magnesium Alloy Stent and the Blood Vessel:A Review

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Journal of materials Science & Technology 2016年第9期32卷 815-826页

作者： JUN MA Department of Chemical Biological and BioengineeringNorth Carolina Agricultural and Technical State UniversityGreensboroNCUSA NSF Engineering Research Center-Revolutionizing Metallic Biomaterials North Carolina Agricultural and Technical State UniversityGreensboroNC USA

Biodegradable magnesium （Mg） alloy stents are the most promising next generation of bio-absorbable stents. In this article, we summarized the progresses on the in vitro studies, animal testing and clinical trials of biodegradable Mg alloy stents in the past decades. These exciting findings led us to propose the importance of the concept ＂bio-adaption＂ between the Mg alloy stent and the local tissue microenvironment after implantation. The healing responses of stented blood vessel can be generally described in three overlapping phases： inflammation, granulation and remodeling. The ideal bio-adaption of the Mg alloy stent, once implanted into the blood vessel, needs to be a reasonable function of the time and the space/dimension. First, a very slow degeneration of mechanical support is expected in the initial four months in order to provide sufficient mechanical support to the injured vessels. Although it is still arguable whether full mechanical support in stented lesions is mandatory during the first four months after implantation, it would certainly be a safety design parameter and a benchmark for regulatory evaluations based on the fact that there is insufficient human in vivo data available, especially the vessel wall mechanical properties during the healing/remodeling phase. Second, once the Mg alloy stent being degraded, the void space will be filled by the regenerated blood vessel tissues. The degradation of the Mg alloy stent should be 100% completed with no residues, and the degradation products （e.g., ions and hydrogen） will be helpful for the tissue reconstruction of the blood vessel. Toward this target, some future research perspectives are also discussed.

关键词： Mg stent Bio-adaptation Vessel Wound healing

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Phase synchronization and energy balance between neurons

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Frontiers of Information Technology & Electronic Engineering 2022年第9期23卷 1407-1420页

作者： Ying XIE Zhao YAO JUN MA Department of Physics Lanzhou University of TechnologyLanzhou730050China School of Science Chongqing University of Posts and TelecommunicationsChongqing430065China

A functional neuron has been developed from a simple neural circuit by incorporating a phototube and a thermistor in different branch circuits.The physical field energy is controlled by the photocurrent across the phototube and the channel current across the thermistor.The firing mode of this neuron is controlled synchronously by external temperature and illumination.There is energy diversity when two functional neurons are exposed to different illumination and temperature conditions.As a result,synapse connections can be created and activated in an adaptive way when field energy is exchanged between neurons.We propose two kinds of criteria to discuss the enhancement of synapse connections to neurons.The energy diversity between neurons determines the increase of the coupling intensity and synaptic current for neurons,and the realization of synchronization is helpful in maintaining energy balance between neurons.The first criterion is similar to the saturation gain scheme in that the coupling intensity is increased with a constant step within a certain period until it reaches energy balance or complete synchronization.The second criterion is that the coupling intensity increases exponentially before reaching energy balance.When two neurons become non-identical,phase synchronization can be controlled during the activation of synapse connections to neurons.For two identical neurons,the second criterion for taming synaptic intensity is effective for reaching complete synchronization and energy balance,even in the presence of noise.This indicates that a synapse connection may prefer to enhance its coupling intensity exponentially.These results are helpful in discovering why synapses are awaken and synaptic current becomes time-varying when any neurons are excited by external stimuli.The potential biophysical mechanism is that energy balance is broken and then synapse connections are activated to maintain an adaptive energy balance between the neurons.These results provide guidance for designing and training intellige

关键词： Hamilton energy Coupling synchronization Synapse enhancement Neural circuit

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Kernel extreme learning machine‐based general solution to forward kinematics of parallel robots

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CAAI Transactions on Intelligence Technology 2023年第3期8卷 1002-1013页

作者： JUN MA Xuechao Duan Dan Zhang Key Laboratory of Electronic Equipment Structure Design of Ministry of Education Xidian UniversityXi'anShaanxiChina Lassonde School of Engineering York UniversityTorontoOntarioCanada

The forward kinematics of parallel robots is a challenging issue due to its highly coupled non‐linear relation among branch chains.This paper presents a novel approach to for-ward kinematics of parallel robots based on kernel extreme learning machine(KELM).To tackle with the forward kinematics solution of fully parallel robots,the forward ki-nematics solution of parallel robots is equivalently transformed into a machine learning model first.On this basis,a computational model combining sparrow search algorithm and KELM is then established,which can serve as both regression and classification.Based on SSA‐optimised KELM(SSA‐KELM)established in this study,a binary discriminator for judging the existence of the forward kinematics solution and a multi‐label regression model for predicting the forward kinematics solution are built to obtain the forward kinematics general solution of parallel robots with different structural configurations and parameters.To evaluate the proposed model,a numerical case on this dataset collected by the inverse kinematics model of a typical 6‐DOF parallel robot is conducted,followed by the results manifesting that the binary discriminator with the discriminant accuracy of 88.50%is superior over ELM,KELM,support vector machine and logistic regression.The multi‐label regression model,with the root mean squared error of 0.06 mm for the position and 0.15°for the orientation,outperforms the double‐hidden‐layer back propagation(2‐BP),ELM,KELM and genetic algorithm‐optimised KELM.Furthermore,numerical cases of parallel robots with different structural con-figurations and parameters are compared with state‐of‐the‐art models.Moreover,these results of numerical simulation and experiment on the host computer demonstrate that the proposed model displays its high precision,high robustness and rapid convergence,which provides a candidate for the forward kinematics of parallel robots.

关键词： artificial intelligence classification machine learning regression analysis robotics

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Designing All‑Solid‑State Batteries by Theoretical Computation:A Review

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Electrochemical Energy Reviews 2023年第1期6卷 790-829页

作者： Shu Zhang JUN MA Shanmu Dong Guanglei Cui Qingdao Industrial Energy Storage Research Institute Qingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdao 266101ShandongChina

All-solid-state batteries(ASSBs)with solid-state electrolytes and lithium-metal anodes have been regarded as a promis-ing battery technology to alleviate range anxiety and address safety issues due to their high energy density and high safety.Understanding the fundamental physical and chemical science of ASSBs is of great importance to battery development.To confirm and supplement experimental study,theoretical computation provides a powerful approach to probe the thermody-namic and kinetic behavior of battery materials and their interfaces,resulting in the design of better batteries.In this review,we assess recent progress in the theoretical computations of solid electrolytes and the interfaces between the electrodes and electrolytes of ASSBs.We review the role of theoretical computation in studying the following:ion transport mechanisms,grain boundaries,phase stability,chemical and electrochemical stability,mechanical properties,design strategies and high-throughput screening of inorganic solid electrolytes,mechanical stability,space-charge layers,interface buffer layers and dendrite growth at electrode/electrolyte interfaces.Finally,we provide perspectives on the shortcomings,challenges and opportunities of theoretical computation in regard to ASSBs.

关键词： Theoretical computation All-solid-state batteries Solid electrolyte Electrode-electrolyte interface

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Recent advances in the application of metal organic frameworks using in advanced oxidation progresses for pollutants degradation

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Chinese Chemical Letters 2022年第12期33卷 5013-5022页

作者： Heshan Zheng Yunying Hou Shuo Li JUN MA jun Nan Tong Li College of Chemistry and Chemical Engineering Qiqihar UniversityQiqihar 161006China Urban Water Resources Development and Northern National Engineering Research Center Harbin 150090China School of Environment Harbin Institute of TechnologyHarbin 150090China School of Energy and Environmental Engineering University of Science and Technology BeijingBeijing 100083China

Metal-organic frameworks(MOFs)materials with highly ordered and porous crystalline structure,have excellent performance in advanced oxidation progresses(AOPs)for organic contaminants degradation in water treatment.This review intends to summarize the timely references and insights for the recent advances in MOFs that are used in AOPs.Starting with the preparation methodologies,including conventional hydrothermal method,electrochemical method,sol-gel method,and emerging microwave and ultrasound assisted synthesis methods.Application and mechanism for MOFs using in various AOPs of Fenton-like,photocatalysis,catalytic ozonation,persulfate catalysis and other emerging oxidation methods are emphatically discussed.We hope this review can comprehensively summarize the research and application progress of MOFs in AOPs,deepen the understanding of the catalytic mechanisms.

关键词： Advanced oxidation progresses Metal-organic frameworks Contaminants degradation Synthesis methods Catalysis mechanism

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Reinfection rates among patients previously infected by SARS-CoV-2:systematic review and meta-analysis

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Chinese Medical Journal 2022年第2期135卷 145-152页

作者： YinJUN MAo Weiwei Wang JUN MA Shanshan Wu Feng Sun Department of Pharmacy First Affiliated Hospital of Fujian Medical UniversityFuzhouFujian 350005China National Clinical Research Center for Mental Disorders and Beijing Key Laboratory of Mental Disorders Beijing Anding HospitalCapital Medical UniversityBeijing 100088China Institute of Basic Medical Sciences Peking University Health Science CenterBeijing 100191China Department of Gastroenterology Beijing Friendship HospitalCapital Medical UniversityNational Clinical Research Center for Digestive DiseaseBeijing Digestive Disease CenterBeijing Key Laboratory for Precancerous Lesion of Digestive DiseaseBeijing100050China Department of Epidemiology and Biostatistics School of Public HealthPeking University Health Science CentreBeijing 100191China

Background:Asymptomatic or symptomatic infection with severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)can be followed by reinfection.The protection conferred by prior infection among coronavirus disease 2019(COVID-19)patients is unclear.We assessed the incidence of SARS-CoV-2 reinfection and the protection effect of previous infection against reinfection.Methods:We searched PubMed,EMBASE,Cochrane,Scopus,Web of Science,and ClinicalTrials.gov for publications up until the end date of may 1,2021.The reinfection rate of recovered patients and the protection against reinfection were analyzed using meta-analysis.Results:Overall,19 studies of 1096 reinfection patients were included.The pooled reinfection rate was 0.65%(95%confidence interval[CI]0.39-0.98%).The symptomatic reinfection rate was a bit lower(0.37%[95%CI 0.11-0.78%],I^(2)=99%).The reinfection rate was much higher in high-risk populations(1.59%[95%CI 0.30-3.88%],I^(2)=90%).The protection against reinfection and symptomatic reinfection was similar(87.02%[95%CI 83.22-89.96%]and 87.17%[95%CI 83.09-90.26%],respectively).Conclusions:The rate of reinfection with SARS-CoV-2 is relatively low.The protection against SARS-CoV-2 after natural infection is comparable to that estimated for vaccine efficacy.These data may help guide public health measures and vaccination strategies in response to the COVID-19 pandemic.High-quality clinical studies are needed to establish the relevant risk factors in recovered patients.

关键词： COVID-19 Reinfection SARS-COV-2 Rate

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S-scheme heterojunction/Schottky junction tandem synergistic effect promotes visible-light-driven catalytic activity

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Nano Research 2023年第2期16卷 2152-2162页

作者： Shuai Wang Xin Du Changhao Yao Yifeng Cai Huiyuan ma Baojiang Jiang JUN MA School of material Science and Chemical Engineering Harbin University of Science and TechnologyHarbin 150040China State Key Laboratory of Urban Water Resource and Environment School of EnvironmentHarbin Institute of TechnologyHarbin 150090China Department of Food and Environment Engineering East University of HeilongjiangHarbin 150066China Key Laboratory of Functional Inorganic material Chemistry Ministry of Education of the People’s Republic of ChinaHeilongjiang UniversityHarbin 150080China

Designing photocatalysts with high light utilization and efficient photogenerated carrier separation for pollutant degradation is one of the important topics for sustainable development.In this study,hierarchical core–shell materialα-Fe_(2)O_(3)@ZnIn_(2)S_(4)with a step-scheme(S-scheme)heterojunction is synthesized by in situ growth technique,and MXene Ti_(3)C_(2)quantum dots(QDs)are introduced to construct a double-heterojunction tandem mechanism.The photodegradation efficiency ofα-Fe_(2)O_(3)@ZnIn_(2)S_(4)/Ti_(3)C_(2)QDs to bisphenol A is 96.1%and its reaction rate constant attained 0.02595 min^(−1),which is 12.3 times that of pureα-Fe_(2)O_(3).Meanwhile,a series of characterizations analyze the reasons for the enhanced photocatalytic activity,and the charge transport path of the S-scheme heterojunction/Schottky junction tandem is investigated.The construction of the S-scheme heterojunction enables the photo-generated electrons ofα-Fe_(2)O_(3)and the holes of ZnIn2S4 to transfer and combine under the action of the reverse built-in electric field.Due to the metallic conductivity of Ti_(3)C_(2)QDs,the photogenerated electrons of ZnIn_(2)S_(4)are further transferred to Ti_(3)C_(2)QDs to form a Schottky junction,which in turn forms a double-heterojunction tandem mechanism,showing a remarkable charge separation efficiency.This work provides a new opinion for the construction of tandem double heterojunctions to degrade harmful pollutants.

关键词： α-Fe_(2)O_(3) ZnIn2S4 MXene Ti_(3)C_(2)quantum dots(QDs) step-scheme heterojunction Schottky junction bisphenol A

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Number of fixed points for unitary T^n-1-manifold

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Frontiers of mathematics in China 2019年第4期14卷 819-831页

作者： Shiyun WEN JUN MA School of mathematical Sciences Capital Normal University Beijing 100048 China College of mathematics Taiyuan University of Technology Taiyuan 030024 China

Let M be a 2n-dimensional closed unitary manifold with a T^n-1- action with only isolated fixed points. In this paper, we first prove that the equivariant cobordism class of a unitary T^n-1-manifold M is just determined by the equivariant Chern numbers C^Tn-1/ω[M], where ω=(i1,i2,…,i6)are the multi-indexes for all i1,i2,…,i6∈N. Then we show that if M does not bound equivariantly, then the number of fixed points is greater than or equal to [n/6]+ 1, where [n/6] denotes the minimum integer no less than n/6.

关键词： Unitary torus manifold equivariant Chern number cobordism localization theorem

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