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Research on the Icing Diagnosis ofWind Turbine Blades Based on FS–XGBoost–EWMA

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Energy Engineering 2024年第7期121卷 1739-1758页

作者： Jicai Guo Xiaowen Song chang Liu Yanfeng Zhang shijie Guo JianxinWu chang Cai Qing’an Li College of Mechanical Engineering Inner Mongolia University of TechnologyHohhot010051China Inner Mongolia Key Laboratory of Special Service Intelligent Robotics Hohhot010051China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing100190China

In winter,wind turbines are susceptible to blade icing,which results in a series of energy losses and safe operation problems.Therefore,blade icing detection has become a top priority.Conventional methods primarily rely on sensor monitoring,which is expensive and has limited applications.Data-driven blade icing detection methods have become feasible with the development of artificial intelligence.However,the data-driven method is plagued by limited training samples and icing samples;therefore,this paper proposes an icing warning strategy based on the combination of feature selection(FS),eXtreme Gradient Boosting(XGBoost)algorithm,and exponentially weighted moving average(EWMA)analysis.In the training phase,FS is performed using correlation analysis to eliminate redundant features,and the XGBoost algorithm is applied to learn the hidden effective information in supervisory control and data acquisition analysis(SCADA)data to build a normal behavior model.In the online monitoring phase,an EWMA analysis is introduced to monitor the abnormal changes in features.A blade icing warning is issued when themonitored features continuously exceed the control limit,and the ambient temperature is below 0℃.This study uses data fromthree icing-affected wind turbines and one normally operating wind turbine for validation.The experimental results reveal that the strategy can promptly predict the icing trend among wind turbines and stably monitor the normally operating wind turbines.

关键词： Wind turbine blade icing feature selection XGBoost EWMA

Influence of EDTA on Demineralization Rate of Dentine:Calcification Treatment in Root Canal Therapy

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Journal of Materials Science & Technology 2014年第7期30卷 692-698页

作者： Yang Ji Min He shijie chang Xiaodong Zhang Huazhe Yang Department of Stomatology General Hospital of Shenyang Military Area Command College of Biomedical Engineering Chongqing Medical University College of Basic Medical Science China Medical University

The aim of this study was to investigate the influence of ethylenediaminetetraacetic acid （EDTA） irrigation on demineralization rate of dentine located in the apical third of root canal walls. Teeth were divided into A and B two groups. In group A, all of the teeth was irrigated with EDTA and NaOCI （sodium hypochlorite）, followed by cutting the apical third into slices longitudinally to examine the influence of EDTA on different portions of apical third of root canal. In group B, the apical third of a tooth was firstly cut into slices longitudinally, followed by coating the root canal walls with EDTA to in-situ observe the demineralization of dentine with different time. It was found that the influence of EDTA on root-canal was gradually increased from the apical to the upper end of the apical third for group A. In addition, the demineralization rate of dentine was remarkable in the first 25 min for group B. The diffusion of EDTA into root dentine would lead to potential damage to the dentine. Furthermore, demineralization rate curve was calculated.

关键词： Ethylenediaminetetraacetic acid （EDTA） Root canal Demineralization Dentine

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Identification of loop-vessel countercurrent arrangements in the early development of mouse kidney based on digital tracing and immunohistochemistry

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Identification of loop-vessel countercurrent arrangements in...

Identification of loop-vessel countercurrent arrangements in the early development of mouse kidney based on digital tracing and immunohistochemistry

中国解剖学会2021年年会

作者： Deng Siqi Ma Yunsheng chang shijie Zhai Xiaoyue Department of Histology and Embryology China Medical University

The proper establishment of loop-vessel countercurrent arrangement in medulla provides the basis for formation of the concentrated urine.To date,the morphogenesis of it has not been fully discovered.The present study investigated the spatial arrangement of nephron loop and vessel of developing kidneys using 3D visualization technique and immunohistochemistry for AQP-1 and NKCC2.Five-mm-thick serial paraffin sections were obtained from E14.5 and P5 kidneys and stained with hematoxylin,while 2.5-mm-thick serial epoxy sections were obtained from E17.5 and P56 kidneys and stained with toluidine blue.

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解剖学杂志 2021年第S1期44卷 171-171页

作者： Deng Siqi Ma Yunsheng chang shijie Zhai Xiaoyue Department of Histology and Embryology China Medical UniversityShenyang 110122China

关键词： kidney immunohistochemistry arrangement

Failure evaluation and control factor analysis of slope block instability along traffic corridor in Southeastern Tibet

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Journal of Mountain Science 2024年第6期21卷 1830-1848页

作者： LIU changqing BAO Han LAN Hengxing YAN changgen LI changbo LIU shijie School of Highway Chang'an UniversityXi'an 710064China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Geological Engineering and Geomatics Chang'an UniversityXi'an 710054China

The instability of slope blocks occurred frequently along traffic corridor in Southeastern Tibet(TCST),which was primarily controlled by the rock mass structures.A rapid method evaluating the control effects of rock mass structures was proposed through field statistics of the slopes and rock mass structures along TCST,which combined the stereographic projection method,modified M-JCS model,and limit equilibrium theory.The instabilities of slope blocks along TCST were then evaluated rapidly,and the different control factors of instability were analyzed.Results showed that the probabilities of toppling(5.31%),planar(16.15%),and wedge(35.37%)failure of slope blocks along TCST increased sequentially.These instability modes were respectively controlled by the anti-dip joint,the joint parallel to slope surface with a dip angle smaller than the slope angle(singlejoint),and two groups of joints inclined out of the slope(double-joints).Regarding the control effects on slope block instability,the stabilization ability of doublejoints(72.7%),anti-dip joint(67.4%),and single-joint(57.6%)decreased sequentially,resulting in different probabilities of slope block instability.Additionally,nearby regional faults significantly influenced the joints,leading to spatial heterogeneity and segmental clustering in the stabilization ability provided by joints to the slope blocks.Consequently,the stability of slope blocks gradually weakened as they approached the fault zones.This paper can provide guidance and assistance for investigating the development characteristics of rock mass structures and the stability of slope blocks.

关键词： Slope engineering Block instability Rapid evaluation method Rock mass structure Control factor

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3D Reconstruction of the medullary tubular-vascular relationship in adult mouse kidneys

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3D Reconstruction of the medullary tubular-vascular relation...

Status and trends in the stability of the three largest ice shelves in Antarctica

中国解剖学会2021年年会

作者： Zhang Jie Yang Jie Jasper S Thomason Arne Andreasen chang shijie Gu Ling Zhai Xiaoyue Department of Histology and Embryology Basic Medicine CollegeChina Medical University Department of Biomedicine-Anatomy Aarhus University Department of Biomedical Engineering China Medical University

A close tubular-vascular relationship in renal medulla is not only the structural basis for urine concentration,but is also the sensitive position for acute and chronic kidney injury.Therefore,a comprehensive understanding of spatial architecture in medulla is important for nephrologist.Serial sections were obtained from three mouse kidneys and double-immunofluorescent stained for CD34 and for either AQP-1 or AQP-2.

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Science China Earth Sciences 2024年第8期 2615-2632页

作者： Rongxing LI Guojun LI Lu AN Menglian XIA Da LV Yuan CHENG Aiguo ZHAO Tian chang Xiangbin CUI Shengkai ZHANG shijie LIU Yixiang TIAN Weian WANG Center for Spatial Information Science and Sustainable Development Applications Tongji University College of Surveying and Geo-informatics Tongji University Postdoctoral Research Station of Shanghai Surveying and Mapping Institute Key Laboratory of Spatial-temporal Big Data Analysis and Application of Natural Resources in Megacities Institute for Conservation of Cultural Heritage School of Cultural Heritage and Information Management Shanghai University Polar Research Institute of China Chinese Antarctic Center of Surveying and Mapping Wuhan University

The Ross, Filchner-Ronne, and Amery ice shelves are the three largest ice shelves in Antarctica, playing a crucial role in supporting the Antarctic ice sheet. However, current studies on the stability of the three largest ice shelves primarily focus on singular or limited factors, lacking a comprehensive assessment of multiple parameters. To systematically and in-depth study the stability and trend of the three largest ice shelves, we comprehensively collected and analyzed key parameters, including elevation changes, basal melting, surface meltwater, major rifts propagation rate, suture zones, ice front area change rate,grounding lines, ice velocity, and mass balance. Additionally, we selected the collapsed Larsen B Ice Shelf(LBIS), the rapidly changing and structurally weakened Pine Island Ice Shelf(PIIS), and the accelerating Totten Ice Shelf(TIS) as reference ice shelves. By comparing and analyzing the key parameters between these reference ice shelves and the three largest ice shelves, we find the status and trends in the stability of the latter. Our findings reveal that most key parameters of the three largest ice shelves present relatively minor variations compared to those of the reference ice shelves. Specifically, 50% of the parameters are smaller than those of the accelerating TIS, 88% are smaller than those of the rapidly changing PIIS, and all parameters are smaller than those of the collapsed LBIS. Furthermore, after analyzing parameters that are not smaller than those of the TIS, it is observed that they remain in a stable state. Hence, the three largest ice shelves are currently undergoing natural changes that do not threaten their stability in the short term. Nevertheless, the evolution of the ice shelves under global climate change remains uncertain,making long-term observation and monitoring essential to assess their impact on sea level rise.

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微燃机回热循环的参数估计与性能分析

热力发电 2024年第6期53卷 87-95页

作者：常有润张士杰王波路源赵丽凤中国科学院先进能源动力重点实验室(工程热物理研究所) 北京100190 中国科学院大学北京100049

以某微燃机循环系统试验台为对象,构建了微燃机回热循环系统模型,并基于此开展了回热循环系统的性能预测与分析。考虑到系统的关键部件性能参数未知,利用极大似然估计法,结合实验数据对其进行了估计,所得预测值和实验值的误差在3%以下,... 详细信息

以某微燃机循环系统试验台为对象,构建了微燃机回热循环系统模型,并基于此开展了回热循环系统的性能预测与分析。考虑到系统的关键部件性能参数未知,利用极大似然估计法,结合实验数据对其进行了估计,所得预测值和实验值的误差在3%以下,表明模型能够较为准确地预测回热循环的热力性能。然后基于建立的模型,开展了全工况的回热循环系统模拟,获得了不同环境温度下随负荷变化时微燃机功率、发电效率、排烟热量和排烟温度等的变化规律以及压气机的工作区间。所获得的微燃机关键部件信息和系统性能变化规律可为相关研究提供一定的参考。

关键词：微燃机回热循环实验参数估计性能分析

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货币政策、经济不确定性与企业投资效率

国际金融研究 2021年第7期 86-96页

作者：李小林常诗杰司登奎中国海洋大学经济学院青岛大学经济学院

本文采用2003—2019年我国A股非金融上市公司的年度数据,深入研究了货币政策对企业投资效率(包括投资过度和投资不足)的影响,重点探讨了这一影响在异质性经济不确定性环境下的潜在差异。研究发现,宽松的货币政策通过增加企业的信贷可得... 详细信息

本文采用2003—2019年我国A股非金融上市公司的年度数据,深入研究了货币政策对企业投资效率(包括投资过度和投资不足)的影响,重点探讨了这一影响在异质性经济不确定性环境下的潜在差异。研究发现,宽松的货币政策通过增加企业的信贷可得性及降低现金流不确定性两种机制改善投资不足企业的投资效率,但同时会降低投资过度企业的投资效率,而较高的经济不确定性会显著弱化这两种机制的潜在作用,由此降低货币政策对投资效率的影响。特别地,经济不确定性会在更大程度上弱化宽松货币政策对高融资约束和高治理水平企业投资不足的影响,但会缓解低融资约束和低治理水平企业投资过度的风险。本文在丰富企业投资效率相关研究的同时,也为经济不确定性条件下完善货币政策调控以促进企业有效投资提供参考。

关键词：货币政策经济不确定性投资过度投资不足投资效率

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