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Optimal Operation Strategy Analysis with Scenario Generation Method Based on Principal Component Analysis,Density Canopy,and K-medoids for Integrated Energy Systems

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journal of Modern Power Systems and Clean Energy 2024年第1期12卷 89-100页

作者： Bingtuan Gao Yunyu zhu Yuanmei Li School of Electrical Engineering Southeast UniversityNanjingChina

The operation of integrated energy systems(IESs)is confronted with great challenges for increasing penetration rate of renewable energy and growing complexity of energy *** generation is one of ordinary methods to alleviate the system uncertainties by extracting several typical scenarios to represent the original high-dimensional *** paper proposes a novel representative scenario generation method based on the feature extraction of panel *** original high-dimensional data are represented by an aggregated indicator matrix using principal component analysis to preserve temporal ***,the aggregated indicator matrix is clustered by an algorithm combining density canopy and *** with the proposed scenario generation method,an optimal operation model of IES is established,where the objective is to minimize the annual operation costs considering carbon trading ***,case studies based on the data of Aachen,Germany in 2019 are *** results indicate that the adjusted rand index(ARI)and silhouette coefficient(SC)of the proposed method are 0.6153 and 0.6770,respectively,both higher than the traditional methods,namely K-medoids,K-means++,and density-based spatial clustering of applications with noise(DBSCAN),which means the proposed method has better *** error between optimal operation results of the IES obtained by the proposed method and all-year time series benchmark value is 0.1%,while the calculation time is reduced from 11029 s to 188 s,which verifies that the proposed method can be used to optimize operation strategy of IES with high efficiency without loss of accuracy.

关键词： Scenario generation principal component analysis(PCA) density canopy K-medoids integrated energy system

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2-local unstable homotopy groups of indecomposable A32-complexes

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Science China Mathematics 2024年第3期67卷 607-626页

作者： Zhongjian zhu jianzhong Pan College of Mathematics and Physics Wenzhou University Hua Loo-Keng Key Laboratory of Mathematics Institute of MathematicsAcademy of Mathematics and Systems ScienceChinese Academy of Sciences School of Mathematical Sciences University of Chinese Academy of Sciences

In this paper,we calculate the 2-local unstable homotopy groups of indecomposable *** main technique used is analysing the homotopy property of j(A,X),defined by Gray(1973) for a Cw-pair(X,A),which is homotopy equival... 详细信息

关键词： homotopy groups A 2 n -complexes fibration sequence relative james construction 55P15

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Partial Collapsing Degeneration of Floer Trajectories and Adiabatic Gluing

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Acta Mathematica Sinica,English Series 2024年第1期40卷 161-249页

作者： Yong-Geun OH Ke zhu Center for Geometry and Physics Institute for Basic Science(IBS)79 Jigok-ro 127beon-gilNam-guPohang-siGyeongsangbuk-doKorea 37673&POSTECHGyeongsangbuk doKorea Department of Mathematics and Statistics Minnesota State UniversityMankatoMN 56001USA

In the present paper,we study partial collapsing degeneration of Hamiltonian-perturbed Floer trajectories for an adiabatic ε-family and its reversal adiabatic gluing,as the prototype of the partial collapsing degeneration of 2-dimensional(perturbed)j-holomorphic maps to 1-dimensional gradient *** consider the case when the Floer equations are S^(1)-invariant on parts of their domains whose adiabatic limit has positive length as ε→0,which we call thimble-flow-thimble *** main gluing theorem we prove also applies to the case with Lagrangian boundaries such as in the problem of recovering holomorphic disks out of pearly *** particular,our gluing theorem gives rise to a new direct proof of the chain isomorphism property between the Morse-Bott version of Lagrangian intersection Floer complex of L by Fukaya-Oh-Ohta-Ono and the pearly complex of L Lalonde and *** also provides another proof of the present authors’earlier proof of the isomorphism property of the PSS map without involving the target rescaling and the scale-dependent gluing.

关键词： Floer trajectory equation partial collapsing degeneration thimble-flow-thimble moduli space adiabatic gluing exponential decay estimates three-interval method

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Association of daily sitting time and leisure-time physical activity with body fat among ***

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journal of Sport and Health Science 2024年第2期13卷 195-203页

作者： jingwen Liao Min Hu Kellie Imm Clifton j.Holmes jie zhu Chao Cao Lin Yang Guangdong Provincial Key Laboratory of Physical Activity and Health Promotion Guangzhou Sport UniversityGuangzhou 510500China Scientific Research Center Guangzhou Sport UniversityGuangzhou 510500China Division of Epidemiology&Genetics Department of Population and Public Health SciencesKeck School of Medicine of the University of Southern CaliforniaLos AngelesCA 90033USA Program in Physical Therapy Washington University School of MedicineSt.LouisMO 63110USA Center for Human Nutrition Washington University School of MedicineSt.LouisMO 63110USA Department of Plastic and Reconstructive Surgery Shanghai East HospitalTongji UniversityShanghai 200070China Department of Cancer Epidemiology and Prevention Research Alberta Health ServicesCalgary T2S 3C3Canada Department of Oncology and Community Health Sciences University of CalgaryCalgary T2N 1N4Canada

Background:Prolonged sitting and reduced physical activity lead to low energy ***,little is known about the joint impact of daily sitting time and physical activity on body fat *** investigated the independent and joint associations of daily sitting time and physical activity with body fat among ***:This was a cross-sectional analysis of *** representative data from the National Health and Nutrition Examination Survey2011-2018 among adults aged 20 years or *** sitting time and leisure-time physical activity(LTPA)were self-reported using the Global Physical Activity *** fat(total and trunk fat percentage)was determined via dual X-ray ***:Among 10,808 adults,about 54.6%spent 6 h/day or more sitting;more than one-half reported no LTPA(inactive)or less than 150 min/week LTPA(insufficiently active)with only 43.3%reported 150 min/week or more LTPA(active)in the past *** fully adjusting for sociodemographic data,lifestyle behaviors,and chronic conditions,prolonged sitting time and low levels of LTPA were associated with higher total and trunk fat percentages in both *** stratifying by LTPA,the association between daily sitting time and body fat appeared to be stronger in those who were inactive/insuufficiently *** the joint analyses,inactive/insuufficiently active adults who reported sitting more than 8 h/day had the highest total(female:3.99%(95%confidence interval(95%CI):3.09%-4.88%);male:3.79%(95%CI:2.75%-4.82%))and trunk body fat percentages(female:4.21%(95%CI:3.09%-5.32%);male:4.07%(95%CI:2.95%-5.19%))when compared with those who were active and sitting less than 4 h/***:Prolonged daily sitting time was associated with increased body fat among *** higher body fat associated with 6 h/day sitting may not be offset by achieving recommended levels of physical activity.

关键词： Adults Body fat distribution Physical activity Sitting time

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Reconfigurable mechanism-based metamaterials for ternary-coded elastic wave polarizers and programmable refraction control

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1225-1242页

作者： Zhou HU Zhibo wEI Yan CHEN Rui zhu School of Aerospace Engineering Beijing Institute of Technology School of Mechanical Engineering Tianjin University Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education Tianjin University

Elastic metamaterials with unusual elastic properties offer unprecedented ways to modulate the polarization and propagation of elastic waves. However, most of them rely on the resonant structural components, and thus are frequency-dependent and unchangeable. Here, we present a reconfigurable 2D mechanism-based metamaterial which possesses transformable and frequency-independent elastic properties. Based on the proposed mechanism-based metamaterial, interesting functionalities, such as ternarycoded elastic wave polarizer and programmable refraction, are demonstrated. Particularly, unique ternary-coded polarizers, with 1-trit polarization filtering and 2-trit polarization separating of longitudinal and transverse waves, are first achieved. Then, the strong anisotropy of the proposed metamaterial is harnessed to realize positive-negative bi-refraction, only-positive refraction, and only-negative refraction. Finally, the wave functions with detailed microstructures are numerically verified.

关键词： elastic metamaterial elastic wave reconfigurable design zero mode ternary code programmable refraction O343 74j05

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Discovery and recognition of scientific values of forty-nine large scale ancient underground engineering in Zhejiang Province

Discovery and recognition of scientific values of forty-nine...

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中国科学院地质与地球物理研究所2015年度（第15届）...

作者： Z.F.Yang Y.j.Shang L.Q.Zhang L.H.Li j.Zhou Q.Gao w.T.He j.w.zhu j.X.Ding G.M.Guo Z.j.Zhang Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of Science Civil Engineering Institute Shandong Jianzhu University

In some areas of Zhcjiang Province such as Longyou County,Tiantai County,wenling City,Sanmen County and Xianju County,forty-nine large-scale ancient underground engineering has been discovered by researchers since the *** of these underground engineering activities is an assemblage of shallow artificial cavern,and all the single caverns total more than *** the Suichang Gold mine formed by gold mining activity,and the Longyou Grottoes whose function was still unidentified,most of the caverns were formed because of stone quarrying activity in ancient *** of these caverns show ultra-large span and *** instance,Cavern No.5 of the Heidong caverns in Tiantai County is a huge domed cavern with a span of 92 m,which is stable for more than 1000 *** might be the world’s first cavern in terms of cavern span In addition,Cavern No.1 of the Changyu caverns in Xinhe Town of wenling City has a span of 56 m and a height of 99 *** cavern,which might be initially quarried in the Northern and Southern Dynasties(some 1500 years ago),is possibly the world’s highest large-span *** submission presents a comprehensive review on the discovery of these ancient underground engineering activities and the scientific values they contain.

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Mechanocatalysis of CO to CO_(2)on TiO_(2)surface controlled at atomic scale

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Nano Research 2024年第7期17卷 5826-5834页

作者： Yuuki Adachi Robert Turanský ján Brndiar Kamil Tokár Qiang zhu Huan Fei wen Yasuhiro Sugawara IvanŠtich Yan jun Li Department of Applied Physics Osaka University2-1 YamadaokaSuitaOsaka 565-0871Japan Institute of Physics Slovak Academy of SciencesBratislava 84511Slovakia Institute of Informatics Slovak Academy of SciencesBratislava 84507Slovakia Faculty of Natural Sciences University of Ss.Cyril and MethodiusTrnava 91701Slovakia Key Laboratory of Instrumentation Science and Dynamic Measurement School of Instrument and ElectronicsNorth University of ChinaTaiyuan 030051China

The common ways to activate a chemical reaction are by heat,electric current,or ***,mechanochemistry,where the chemical reaction is activated by applied mechanical force,is less common and only poorly understood at the atomic *** we report a tip-induced activation of chemical reaction of carbon monoxide to dioxide on oxidized rutile TiO_(2)(110)*** activation is studied by atomic force microscopy,Kelvin probe force microscopy under ultrahigh-vacuum and liquid nitrogen temperature conditions,and density functional theory(DFT)*** reaction is inferred from hysteretic behavior of frequency shift signal further supported by vector force mapping of vertical and lateral forces needed to trigger the chemical reaction with torque motion of carbon monoxide towards an oxygen *** reaction is found to proceed stochastically at very small tip-sample ***,the local contact potential difference reveals the atomic-scale charge redistribution in the reactants required to unlock the *** results open up new insights into the mechanochemistry on metal oxide surfaces at the atomic scale.

关键词： atomic resolution mechanochemistry atomic force microscopy Kelvin probe force microscopy density functional theory(DFT)simulation CO oxidation catalysis rutile TiO_(2)surface

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On the Trail of Self-Directed Online Learners

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ECNU Review of Education 2024年第2期7卷 406-419页

作者： Curtis j.Bonk 朱美娜 School of Education Indiana University201 N.Rose AvenueBloomingtonIN 4740lUSA wayne State University

Purpose we describe a series of more than a dozen studies on self-directed online learning spanning over a ***/Approach/Methods we incorporated surveys,interviews,focus groups,and content analyses into these research studies,which initially targeted the goals,motivations,and challenges of learners using open educational resources and OpenCourseware and then focused on learning from massive open online courses(MOOCs).This research accelerated after creating a database of over 3,000 MOOC instructors,through which we explored cultural sensitivity and personalization practices in MOOCs as well as instructional design considerations and challenges,MOOC instructor professional development and career development,instructor motivation and engagement,and student and instructor perceptions of self-directed *** This study reveals that self-directed online learners(SDOLs)seek learning environments offering freedom,choice,control,and a sense of autonomy and that both learners and instructors have intrinsic motivation for engaging in open online learning ***/Value Based on this research with both MOOC instructors and MOOC learners,we offer instructional design guidelines to address SDOLs’needs and assist in efforts to foster a new generation of SDOLs.

关键词： MOOCs motivation online learning self-directed learning self-management self-monitoring

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Improvement of Film Cooling Design for Turbine Vane Leading Edge Considering Combustor Outflow

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journal of Thermal Science 2024年第1期33卷 311-327页

作者： wANG Xinyu LIU Cunliang FU Zhongyi LI Yang zhu Huiren School of Power and Energy Northwestern Polytechnical UniversityXi'an 710072China AECC Hunan Aviation Powerplant Research Institute Zhuzhou 412002China

As the interaction between the combustor and the turbine in the aero-engine continues to increase,the film cooling design considering the combustor swirling outflow has become the research *** swirling inflow and high-temperature gas first affect the vane leading edge(LE).However,no practical improved solution for the LE cooling design has been proposed considering the combustor swirling *** this paper,the improved scheme of showerhead cooling is carried out around the two ways of adopting the laid-back-fan-shaped hole and reducing the coolant outflow *** film cooling effectiveness(η) and the coolant flow state are obtained by PSP(pressure-sensitive-paint) and numerical simulation methods,*** research results show that the swirling inflow increases the film distribution inhomogeneity by imposing the radial pressure gradient on the vane to make the film excessively gather in some *** showerhead film cooling adopts the laid-back-fan-shaped hole to reduce the momentum when the coolant flows *** this cooling scheme improves the film attachment and increases the surface-averaged film cooling effectiveness(η_(sur)) by as much as15.4%,the film distribution inhomogeneity *** reducing the coolant outlet angle,the wall-tangential velocity of the coolant increases,and the wall-normal velocity *** the swirl intake condition,both ηand the film distribution uniformity are significantly increased,and the growth of η_(sur) is up to 16.5%.This paper investigates two improved schemes to improve the showerhead cooling under the swirl intake condition to provide a reference for the vane cooling design.

关键词： turbine vane showerhead cooling swirling inflow laid-back-fan-shaped hole film hole inclination

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Fault Estimation for a Class of Markov jump Piecewise-Affine Systems: Current Feedback Based Iterative Learning Approach

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IEEE/CAA journal of Automatica Sinica 2024年第2期11卷 418-429页

作者： Yanzheng zhu Nuo Xu Fen wu Xinkai Chen Donghua Zhou IEEE College of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdao 266590China College of Mechanical Engineering and Automation Huaqiao UniversityXiamen 361021China Department of Mechanical and Aerospace Engineering North Carolina State UniversityRaleigh NC 27695 USA Department of Electronic and Information Systems Shibaura Institute of TechnologySaitama 337-8570Japan

In this paper, the issues of stochastic stability analysis and fault estimation are investigated for a class of continuoustime Markov jump piecewise-affine(PwA) systems against actuator and sensor faults. Firstly, a novel mode-dependent PwA iterative learning observer with current feedback is designed to estimate the system states and faults, simultaneously, which contains both the previous iteration information and the current feedback mechanism. The auxiliary feedback channel optimizes the response speed of the observer, therefore the estimation error would converge to zero rapidly. Then, sufficient conditions for stochastic stability with guaranteed performance are demonstrated for the estimation error system, and the equivalence relations between the system information and the estimated information can be established via iterative accumulating ***, two illustrative examples containing a class of tunnel diode circuit systems are presented to fully demonstrate the effectiveness and superiority of the proposed iterative learning observer with current feedback.

关键词： Current feedback fault estimation iterative learning observer Markov jump piecewise-affine system

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