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A Fluctuation Test for Structural Change Detection in Heterogeneous Panel Data Models

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Journal of Systems Science & Complexity 2024年第3期37卷 1184-1208页

作者： LI Fuxiao xiao Yanting chen Zhanshou Department of Applied Mathematics Xi'an University of TechnologyXi'an 710048China School of Mathematics and Statistics Qinghai Normal UniversityXining 810008China Academy of Plateau Science and Sustainability Xining 810008China

Structural change in panel data is a widespread phenomena. This paper proposes a fluctuation test to detect a structural change at an unknown date in heterogeneous panel data models with or without common correlated effects. The asymptotic properties of the fluctuation statistics in two cases are developed under the null and local alternative hypothesis. Furthermore, the consistency of the change point estimator is proven. Monte Carlo simulation shows that the fluctuation test can control the probability of type I error in most cases, and the empirical power is high in case of small and moderate sample sizes. An application of the procedure to a real data is presented.

关键词： Common correlated effects fuctuation test heterogeneous panel data models structural change detection

Log interpretation of carbonate rocks based on petrophysical facies constraints

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Energy Geoscience 2024年第3期5卷 39-51页

作者： hui Xu Hongwei xiao Guofeng cheng Nannan Liu Jindong Cui Xing Shi Shangping chen School of Petroleum and Natural Gas Engineering Changzhou UniversityChangzhouJiangsu213164China Exploration and Development Research Institute of Daqing Oilfield Co. Ltd.DaqingHeilongjiang163712China Changqing Oilfield No.5 Oil Production Plant PetroChinaXi'anShannxi710000China

The complex pore structure of carbonate reservoirs hinders the correlation between porosity and *** view of the sedimentation,diagenesis,testing,and production characteristics of carbonate reservoirs in the study area,combined with the current trends and advances in well log interpretation techniques for carbonate reservoirs,a log interpretation technology route of“geological information constraint+deep learning”was *** principal component analysis(PCA)was employed to establish lithology identification criteria with an accuracy of 91%.The Bayesian stepwise discriminant method was used to construct a sedimentary microfacies identification method with an accuracy of 90.5%.Based on production data,the main lithologies and sedimentary microfacies of effective reservoirs were determined,and 10 petrophysical facies with effective reservoir characteristics were *** by petrophysical facies,the mean interpretation error of porosity compared to core analysis results is 2.7%,and the ratio of interpreted permeability to core analysis is within one order of magnitude,averaging *** research results demonstrate that deep learning algorithms can uncover the correlation in carbonate reservoir well logging *** geological and production data and selecting appropriate machine learning algorithms can significantly improve the accuracy of well log interpretation for carbonate reservoirs.

关键词： Carbonate reservoir Principal component analysis(PCA) Bayesian stepwise discriminant analysis Petrophysical facies Well log interpretation

Bibliometric analysis of research in epilepsy and comorbid depression from 2014 to 2023

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World Journal of Psychiatry 2024年第6期14卷 985-998页

作者： Ling chen xiao-hui He Xia-Ling Li Juan Yang Hao Huang Department of Neurology The Affiliated Hospital of Zunyi Medical UniversityZunyi 563003Guizhou ProvinceChina Department of Neurology Xinqiao Hospital and the Second Affiliated HospitalArmy Medical University(Third Military Medical University)Chongqing 400010China

BACKGROUND Epilepsy and depression have complicated bidirectional *** study aimed to explore the field of epilepsy comorbid with depression in a bibliometric perspective from *** To improve our understanding of epilepsy and depression by evaluating the relationship between epilepsy and depression,bibliometric analyses were *** Epilepsy and depression-related publications from the last decade were retrieved from the Web of Science Core *** conducted bibliometric and visual analysis using VOSviewer and CiteSpace,examining authorships,countries,institutions,journals of publication,co-citations of references,connections between keywords,clusters of keywords,and keywords with citation *** Over the past ten years,we collected 1045 research papers focusing on the field of epilepsy and comorbid *** on epilepsy and depression have shown a general upward trend over time,though with some *** United States,with 287 articles,and the University of Melbourne,contributing 34 articles,were the top countries and institutions,*** addition,in the field of epilepsy and depression,Professor Lee,who has published 30 articles,was the most contributing *** hot topics pay attention to the quality of life in patients with epilepsy and *** We reported that quality of life and stigma in patients with epilepsy comorbid with depression are possible future hot topics and directions in the field of epilepsy and depression research.

关键词： Epilepsy Depression Bibliometrics VOSviewer CiteSpace Visualization analysis

Research progress in CALPHAD assisted metal additive manufacturing

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China Foundry 2024年第4期21卷 295-310页

作者： Ya-qing Hou xiao-qun Li Wei-dong Cai Qing chen Wei-ce Gao Du-peng He Xue-hui chen Hang Su China Iron&Steel Research Institute Group Beijing 100081China Thermo-Calc Software AB SolnaSE-169Sweden KTH Royal Institute of Technology StockholmSE-100Sweden Central Iron and Steel Research Institute Beijing 100081China

Metal additive manufacturing(MAM)technology has experienced rapid development in recent *** both equipment and materials progress towards increased maturity and commercialization,material metallurgy technology based on high energy sources has become a key factor influencing the future development of *** calculation of phase diagrams(CALPHAD)is an essential method and tool for constructing multi-component phase diagrams by employing experimental phase diagrams and Gibbs free energy models of simple *** combining with the element mobility data and non-equilibrium phase transition model,it has been widely used in the analysis of traditional metal *** development of CALPHAD application technology for MAM is focused on the compositional design of printable materials,the reduction of metallurgical imperfections,and the control of microstructural *** endeavor carries considerable theoretical and practical *** paper summarizes the important achievements of CALPHAD in additive manufacturing(AM)technology in recent years,including material design,process parameter optimization,microstructure evolution simulation,and properties ***,the limitations of applying CALPHAD technology to MAM technology are discussed,along with prospective research directions.

关键词： metal additive manufacturing CALPHAD integrated computational material engineering powder bed fusion material design microstructure simulation

An improved algorithm for retrieving thin sea ice thickness in the Arctic Ocean from SMOS and SMAP L-band radiometer data

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Acta Oceanologica Sinica 2024年第3期43卷 127-138页

作者： Lian He Senwen Huang Fengming hui xiao cheng School of Geospatial Engineering and Science Sun Yat-Sen Universityand Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Key Laboratory of Comprehensive Observation of Polar Environment(Sun Yat-Sen University) Ministry of EducationZhuhai 519082China

The aim of this study was to develop an improved thin sea ice thickness(SIT)retrieval algorithm in the Arctic Ocean from the Soil Moisture Ocean Salinity and Soil Moisture Active Passive L-band radiometer *** SIT retrieval algorithm was trained using the simulated SIT from the cumulative freezing degree days model during the freeze-up period over five carefully selected regions in the Beaufort,Chukchi,East Siberian,Laptev and Kara seas and utilized the microwave polarization ratio(PR)at incidence angle of 40°.The improvements of the proposed retrieval algorithm include the correction for the sea ice concentration impact,reliable reference SIT data over different representative regions of the Arctic Ocean and the utilization of microwave polarization ratio that is independent of ice *** relationship between the SIT and PR was found to be almost stable across the five selected *** SIT retrievals were then compared to other two existing algorithms(i.e.,UH_SIT from the University of Hamburg and UB_SIT from the University of Bremen)and validated against independent SIT data obtained from moored upward looking sonars(ULS)and airborne electromagnetic(EM)induction *** results suggest that the proposed algorithm could achieve comparable accuracies to UH_SIT and UB_SIT with root mean square error(RMSE)being about 0.20 m when validating using ULS SIT data and outperformed the UH_SIT and UB_SIT with RMSE being about 0.21 m when validatng using EM SIT *** proposed algorithm can be used for thin sea ice thickness(<1.0 m)estimation in the Arctic Ocean and requires less auxiliary data in the SIT retrieval procedure which makes its implementation more practical.

关键词： Arctic sea ice sea ice thickness remote sensing Soil Moisture Active Passive(SMAP) Soil Moisture Ocean Salinity and Soil(SMOS)

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PDV分解结合三元组的视角无关动作识别

控制工程 2015年第5期22卷 1010-1016页

作者：陈小辉榆林学院信息工程学院陕西榆林719000

人体动作识别是计算机图像处理领域一个非常重要的研究课题,但是由于视角的多变性以及摄像机内部参数的多样性,给动作识别造成了诸多困难。提出了一种基于投影深度向量(Projective Depth Volume,PDV)分解结合三元组的视角无关人体动作... 详细信息

人体动作识别是计算机图像处理领域一个非常重要的研究课题,但是由于视角的多变性以及摄像机内部参数的多样性,给动作识别造成了诸多困难。提出了一种基于投影深度向量(Projective Depth Volume,PDV)分解结合三元组的视角无关人体动作识别算法,该算法合理地结合了三元组策略,是引入特征向量视角无关动作识别算法的有效扩展。其核心是对每个帧平面使用身体三元组提取每个点的投影深度,通过标识人体为一组点将身体姿势分解为一组投影深度,用于识别各种视角的身体点运动,并通过投影深度来度量2个动作之间的相似度。在包括CMU Mo Cap数据集、IXMAS数据集和MSR Action3D数据集上的大量实验表明,即使在视角和摄像参数未知的情况下,也能准确识别人体动作,识别率分别达到96.0%,87.3%和90.2%,高于其他几种优秀算法。

关键词：动作识别视角无关三元组投影深度向量特征分解

Self-assembly of differentiated dental pulp stem cells facilitates spheroid human dental organoid formation and prevascularization

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World Journal of Stem Cells 2024年第3期16卷 287-304页

作者： Fei Liu Jing xiao Lei-hui chen Yu-Yue Pan Jun-Zhang Tian Zhi-Ren Zhang xiao-Chun Bai School of Basic Medical Sciences Southern Medical UniversityGuangzhou 510515Guangdong ProvinceChina Department of Health Management Guangdong Second Provincial General HospitalGuangzhou 510317Guangdong ProvinceChina Guangdong Provincial Key Laboratory of Tumor Interventional Diagnosis and Treatment Zhuhai People’s Hospital Affiliated with Jinan UniversityZhuhai 519000Guangdong ProvinceChina Centre of Reproduction Development and AgingFaculty of Health SciencesUniversity of MacaoMacao 999078China Department of Stomatology Guangdong Second Provincial General HospitalGuangzhou 510317Guangdong ProvinceChina Zhuhai Institute of Translational Medicine Zhuhai Hospital Affiliated with Jinan UniversityZhuhai 519000Guangdong ProvinceChina Department of Cell Biology School of Basic Medical SciencesSouthern Medical UniversityGuangzhou 510515Guangdong ProvinceChina

BACKGROUND The self-assembly of solid organs from stem cells has the potential to greatly expand the applicability of regenerative *** cells can self-organise into microsized organ units,partially modelling tissue function and *** pulp organoids have been used to recapitulate the processes of tooth development and related ***,the lack of vasculature limits the utility of dental pulp *** To improve survival and aid in recovery after stem cell transplantation,we demonstrated the three-dimensional(3D)self-assembly of adult stem cell-human dental pulp stem cells(hDPSCs)and endothelial cells(ECs)into a novel type of spheroid-shaped dental pulp organoid in vitro under hypoxia and conditioned medium(CM).METHODS During culture,primary hDPSCs were induced to differentiate into ECs by exposing them to a hypoxic environment and *** hypoxic pretreated hDPSCs were then mixed with ECs at specific ratios and conditioned in a 3D environment to produce prevascularized dental pulp *** biological characteristics of the organoids were analysed,and the regulatory pathways associated with angiogenesis were *** The combination of these two agents resulted in prevascularized human dental pulp organoids(Vorganoids)that more closely resembled dental pulp tissue in terms of morphology and ***-cell RNA sequencing of dental pulp tissue and RNA sequencing of Vorganoids were integrated to analyse key regulatory pathways associated with *** biomarkers forkhead box protein O1 and fibroblast growth factor 2 were identified to be involved in the regulation of *** In this innovative study,we effectively established an in vitro model of Vorganoids and used it to elucidate new mechanisms of angiogenesis during regeneration,facilitating the development of clinical treatment strategies.

关键词： Human dental pulp stem cells Prevascularized organoids Integrated analyses Angiogenesis Forkhead box protein O1

Influence of crystal-transforming agent on the performance and mechanism ofα-high-strength gypsum prepared from FGD gypsum

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Particuology 2024年第4期87卷 37-45页

作者： Zhuoyue Xu xiao Wang Biao Jin Dawang Zhang hui Li College of Materials Science and Engineering Xi'an University of Architecture and TechnologyXi'an710055China Schoolof Materials and Chemical Engineering Henan University of Urban ConstructionPingdingshan46736China

This paper investigates the impact of flue gas desulfurization(FGD)gypsum's crystal modifier on the characteristics and microcosmic mechanism ofα-high strength *** results demonstrate that all three crystal modifiers can convert FGD gypsum toα-high-strength *** acid(CA)has the most significant influence onα-high-strength gypsum,and the preparedα-high-strength gypsum is short columnar,with an aspect ratio in the range of 1-3,and has a faster setting time,a larger specific surface area,and a smaller standard consistency,higher compressive strength,greater surface hardness,and smaller crystal particle *** initial setting time of theα-high-strength gypsum manufactured with CA crystal modifier was decreased by 36%compared to the blank sample,the final setting time was lowered by 37.5%,and the water consumption of the standard consistency was reduced by 8%.The maximum strength is 32 MPa after 2 h,the absolute dry compressive strength is up to 38 MPa,and the surface hardness is improved by 24.43%.

关键词： Flue gas desulfurization gypsum Crystal modifier Microscopic mechanism α-high-strength gypsum

Surface reconstruction and structural transformation of twodimensional Ni-Fe MOFs for oxygen evolution in seawater media

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Nano Research 2024年第4期17卷 2429-2437页

作者： Liyuan xiao Xue Bai Jingyi Han Tianmi Tang Siyu chen hui Qi Changmin Hou Fuquan Bai Zhenlu Wang Jingqi Guan Institute of Physical Chemistry College of ChemistryJilin UniversityChangchun 130021China The Second Hospital of Jilin University Changchun 130021China State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin UniversityChangchun 130012China Laboratory of Theoretical and Computational Chemistry Institute of Theoretical ChemistryCollege of ChemistryChangchun 130023China

As a four-electron transfer reaction,oxygen evolution reaction(OER)is limited by large overpotential and slow ***,we in-situ synthesized two-dimensional(2D)Ni-Fe metal-organic framework nanosheets on nickel foam(NixFe-TPA/NF,TPA=terephthalic acid)for oxygen evolution in alkaline and alkaline seawater *** 1 M KOH,Ni3Fe-TPA/NF shows a low overpotential(η10)of 189 mV at 10 mA·cm^(-2) and an ultra-low overpotential of only 260 mV at 500 mA·cm^(-2).In alkaline seawater,Ni3Fe-TPA/NF still provides impressive OER performance,with anη10 of 265 ***-situ Raman characterization results show that the phase transition occurs during the OER,and Ni3FeOOH with more oxygen vacancies is in-situ formed,reducing the OER energy *** functional theory(DFT)reveals that the synergy between Ni and Fe reduces the energy barrier and accelerates the rate-determining *** addition,the ultra-thin 2D sheet structure and the close combination of Ni3FeOOH and highly conductive NF support ensure the high catalytic OER ***,the surface reconstruction and structural modification strategy can be used to design and prepare high-performance OER electrocatalysts for energy-related applications.

关键词： density functional theory(DFT)calculation Ni3FeOOH oxygen evolution reaction seawater electrolysis surface reconstruction