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Some rigid results on doubly twisted product complex Finsler manifolds

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Science China Mathematics 2025年第2期68卷 421-432页

作者： Hongchuan Xia wei Xiao Chunping Zhong School of Mathematics and Statistics Xinyang Normal UniversityXinyang 464000China School of Mathematical Sciences Xiamen UniversityXiamen 361005China

Let(M1×(λ_(1),λ_(2))M_(2),F)be a doubly twisted product complex Finsler manifold of two strongly pseudoconvex complex Finsler manifolds(M_(1),F_(1))and(M_(2),F_(2)).Denote by M the product manifold of M1and M_(2).In this paper,we first give the characterization for(M,F)to be of constant holomorphic curvature,and prove that(M,F)is of constant holomorphic curvature if and only if(M,F),(M_(1),F_(1)),and(M_(2),F_(2))all have vanishing holomorphic curvature under the condition that lnλ_(1)and lnλ_(2)are both pluriharmonic ***,we obtain the classification for(M,F)to be a complex Landsberg ***,we prove that a strongly convex doubly twisted product complex Finsler manifold(M,F)is projectively flat(*** flat)if and only ifλ_(1)F1andλ_(2)F_(2)are both complex Minkowski metrics.

关键词： doubly twisted product complex Finsler manifold holomorphic curvature complex Landsberg manifold

体育强国背景下中华体育精神融入高职体育课程思政的研究与实践

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包头职业技术学院学报 2024年第2期25卷 101-104,119页

作者：韦春生李凤华北京工业职业技术学院体育部北京100042

中华体育精神是建设体育强国的精神支撑,具有不可替代的作用和价值。课程思政教育是高职院校体育教学的重要组成部分,促进两者有效融合,对于人才培养功不可没。本文概述体育强国、中华体育精神、体育课程思政的内涵和要义,分析研究中华... 详细信息

中华体育精神是建设体育强国的精神支撑,具有不可替代的作用和价值。课程思政教育是高职院校体育教学的重要组成部分,促进两者有效融合,对于人才培养功不可没。本文概述体育强国、中华体育精神、体育课程思政的内涵和要义,分析研究中华体育精神融入高职体育课程思政的时代价值,从多个方面进行探索与实践,实现体育课程思政的育人功能。

关键词：中华体育精神体育课程思政高职体育

Dative B–N bonds weaven toward two-dimensional purely organic materials for single crystals

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Science China Chemistry 2025年第1期68卷 12-14页

作者： wei-Lei Zhou Siwei Wang Yong Chen College of Chemistry and Materials Science Inner Mongolia Key Laboratory of Chemistry for Nature Products and Synthesis for Functional MoleculesInnovation Team of Optical Functional Molecular DevicesInner Mongolia Minzu UniversityTongliao 028000China College of Chemistry Nankai UniversityTianjin 300071China

Molecular topology is one of the important topics to study and understand the relationship between molecular structure and properties^([1]).Particularly,two-dimensional(2D)materials with extremely high surface area and ultra-thin morphology have attracted considerable attention due to their unexpected properties in materials and chemistry^([2,3]).

关键词： bonds purely dimensional

No-go guide for the Hubble tension:Late-time or local-scale new physics

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Science China(Physics,Mechanics & Astronomy) 2025年第2期68卷 73-85页

作者： Lu Huang Shao-Jiang Wang Wang-wei Yu CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of Sciences(CAS)Beijing100190China Asia Pacific Center for Theoretical Physics(APCTP) Pohang37673Korea Max-Planck-Institut für Gravitationsphysik(Albert-Einstein-Institut) HannoverD-30167Germany Leibniz Universität Hannover Hannover30167Germany

The standard model of modern cosmology might be cracked by the recent persistent hot debate on the Hubble-constant(H_(0))tension,which manifests itself as the sound-horizon(r_(s))tension or absolute-magnitude(M_(B))tension if deeming the origin of the Hubble tension from modifying the early or late Universe,*** this study,we achieve a fully model-independent constraint(fitting a model-independent global parameterization to a model-independent inverse distant ladder with a modelindependent high-redshift calibration)on late-time models with strong evidence against homogeneous new physics over theΛ-cold-dark-matter(ΛCDM)*** using this model-independent constraint to calibrate sufficiently local supernovae with corresponding late-time models extrapolated below the homogeneity scale,we find surprisingly that,although both H_(0)tension and MB tension are absent in our local Universe,a combination of H_(0)and M_(B)as the intercept a B of the magnitude-redshift relation exhibits 3~7σtension even for theΛCDM *** aBtension seems to call for local-scale inhomogeneous new physics disguised as local observational systematics.

关键词： Hubble constant inverse distance ladder local Universe

Applications of in-situ solid-state nuclear magnetic resonance in methanol to olefins reaction

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Science China Chemistry 2025年第1期68卷 134-151页

作者： Jing Niu Shutao Xu Yingxu wei Zhongmin Liu National Engineering Research Center of Lower-Carbon Catalysis Technology Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China University of Chinese Academy of Sciences Beijing 100049China

The methanol-to-olefins(MTO)reaction offers an alternative pathway for the production of low-carbon olefins from non-oil *** research has been impeded by a lack of comprehensive understanding of its underlying mechanism,despite the significant progress made in ***-situ solid-state nuclear magnetic resonance(ss NMR)spectroscopy has emerged as a pivotal tool,offering crucial insights into key species under real-time operando ***,the host–guest interaction between zeolites or surface species residing on zeolites and the reactant/active intermediates is revealed by the combination of in-situ^(13)C MAS NMR and 2D correlation ***,recent technological advancements in hyperpolarization(HP)methods,including HP^(129)Xe NMR and dynamic nuclear polarization(DNP),have significantly improved the sensitivity of ssNMR,enabling detailed structural and kinetic analysis as well as the detection of trace *** this feature article,we summarized recent advancements in(in-situ)ssNMR spectroscopy applied to MTO reaction processes,encompassing mechanistic investigations at various stages and the intricate host–guest *** theoretical insights into the dynamic evolution of MTO reactions lay a solid foundation for the optimization of catalytic processes and the development of efficient catalysts,thereby advancing the techniques towards more sustainable and economical production route for olefins.

关键词： MTO zeolites in-situ ssNMR reactive intermediates reaction mechanism

Three-dimensional fracture of UO_(2)ceramic pellets by phase field modeling

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Science China(Physics,Mechanics & Astronomy) 2025年第1期68卷 165-176页

作者： wei Xiong Xuan Ye Hongzhang Cheng Xiaoming Liu Institute of Nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyKey Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing 100084China State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

Fracture is the primary failure type for the UO_(2)ceramic pellets,which are operated under irradiation and thermal processes,and physically confined by the *** this work,by combining closely coupled physical processes of heat conduction,heat transfer,and mechanical deformation with the cohesive phase field framework,we proposed a high-precision modeling of quasistatic cracking of three-dimensional(3D)UO_(2)ceramic fuel pellets under high temperature and *** simulation results agree well with the experimental results,indicating that the proposed method has the potential to capture 3D crack modes in the interested time ***,we studied the relation of the 3D fracture patterns of fuel pellets with the peak power *** was found that the power level plays a critical role in determining the competition between radial and circumferential cracks,as well as transverse penetrating cracks.

关键词： phase field method nuclear fuel pellet coupled thermo-mechanical model thermal fracture

A six-variable quasi-3D isogeometric approach for free vibration of functionally graded graphene origami-enabled auxetic metamaterial plates submerged in a fluid medium

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 157-176页

作者： wei CHEN Zhihong TANG Yufen LIAO Linxin PENG College of Civil Engineering University of South China College of Civil Engineering and Architecture Guangxi University Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education Guangxi University

This paper presents, for the first time, an effective numerical approach based on the isogeometric analysis(IGA) and the six-variable quasi-three dimensional(3D)higher-order shear deformation theory(HSDT) to study the free vibration characteristics of functionally-graded(FG) graphene origami(GOri)-enabled auxetic metamaterial(GOEAM) plates submerged in a fluid medium. The plate theory incorporates the thickness stretching and the effects of transverse shear deformation without using any shear correction factors. The velocity potential function and Bernoulli's equation are used to derive the hydrodynamic pressure acting on the plate surface. Both horizontally and vertically immersed plate configurations are considered here in the form of inertia *** plates are composed of multilayer GOEAMs, with the GOri content varying through the plate's thickness in a layer-wise manner. This design results in graded auxetic *** material properties are evaluated by mixing rules and a genetic programming(GP)-assisted micromechanical model. The governing equations of motion for the FG-GOEAM plates immersed in a fluid medium are derived by Hamilton's principle. After validating the convergence and accuracy of the present model, a comprehensive parametric study is carried out to examine the effects of the GOri content, GOri distribution pattern, GOri folding degree, fluid level, immersed depth, and geometric parameter on the natural frequencies of the FG-GOEAM plates. The results show that the natural frequencies for the four GOri distribution patterns increase with the increase in the layer number when the lay number is fewer than 10, and then stabilize after the layer number reaches ***, in general, the natural frequency of the FG-GOEAM plate in a vacuum or fluid increases when the GOri content increases, while decreases when the GOri folding degree increases. Some additional findings related to the numerical results are presented in the conclusions. It is belie

关键词： free vibration functionally-graded (FG) graphene origami (GOri)-enabled auxetic metamaterial (GOEAM) plate hydrodynamic pressure isogeometric analysis (IGA) O321 quasi-three dimensional (3D) higher-order shear deformation theory (HSDT)

PowerV垂直钻井技术在克拉2气田的应用

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石油钻采工艺 2004年第6期26卷 4-8页

作者：王春生魏善国殷泽新塔里木油田公司新疆库尔勒841000

随着塔里木油田在山前构造区域勘探开发力度的不断增大 ,防斜打快技术成为制约塔里木地区山前构造勘探开发钻井进程的关键技术。位于新疆库车凹陷山前构造的克拉 2气田是西气东输工程的主力气源地 ,目前进入了大规模开发阶段。简述了克... 详细信息

随着塔里木油田在山前构造区域勘探开发力度的不断增大 ,防斜打快技术成为制约塔里木地区山前构造勘探开发钻井进程的关键技术。位于新疆库车凹陷山前构造的克拉 2气田是西气东输工程的主力气源地 ,目前进入了大规模开发阶段。简述了克拉 2气田的地层特征 ,评价了山前高陡构造防斜打快技术 ,介绍了PowerV垂直钻井新技术工作原理及其应用方法 ,列举了其在西气东输克拉 2气田 2口直井开发井 4 0 6 .4mm井眼段的应用情况 ,并在技术和效益方面对应用情况作了评价 ,认为PowerV垂直钻井技术可完全解放钻压 ,变被动防斜为主动防斜 ,对将来山前高陡构造防斜打快、缩短钻井周期、降低钻井成本具有一定的借鉴意义。

关键词：克拉2气田钻井技术防斜打快技术高陡构造开发井钻井周期直井主力勘探开发区域

Recent progress on artificial intelligence-enhanced multimodal sensors integrated devices and systems

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Journal of Semiconductors 2025年第1期46卷 179-192页

作者： Haihua Wang Mingjian Zhou Xiaolong Jia Hualong wei Zhenjie Hu wei Li Qiumeng Chen Lei Wang College of Integrated Circuit Science and Engineering Nanjing University of Posts and TelecommunicationsNanjing 210023China Nantong Institute of Nanjing University of Posts and Telecommunications Nantong 226021China

Multimodal sensor fusion can make full use of the advantages of various sensors,make up for the shortcomings of a single sensor,achieve information verification or information security through information redundancy,and improve the reliability and safety of the *** intelligence(AI),referring to the simulation of human intelligence in machines that are programmed to think and learn like humans,represents a pivotal frontier in modern scientific *** the continuous development and promotion of AI technology in Sensor 4.0 age,multimodal sensor fusion is becoming more and more intelligent and automated,and is expected to go further in the *** this context,this review article takes a comprehensive look at the recent progress on AI-enhanced multimodal sensors and their integrated devices and *** on the concept and principle of sensor technologies and AI algorithms,the theoretical underpinnings,technological breakthroughs,and pragmatic applications of AI-enhanced multimodal sensors in various fields such as robotics,healthcare,and environmental monitoring are *** a comparative study of the dual/tri-modal sensors with and without using AI technologies(especially machine learning and deep learning),AI-enhanced multimodal sensors highlight the potential of AI to improve sensor performance,data processing,and decision-making ***,the review analyzes the challenges and opportunities afforded by AI-enhanced multimodal sensors,and offers a prospective outlook on the forthcoming advancements.

关键词： sensor multimodal sensors machine learning deep learning intelligent system