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Time-Domain Analysis of Body Freedom Flutter Based on 6DOF Equation

工程与科学中的计算机建模(英文) 2024年第1期138卷 489-508页

作者： Zhehan Ji Tongqing Guo Di Zhou Zhiliang Lu binbin lyu Key Laboratory of Unsteady Aerodynamics and Flow Control Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsNanjing210016China High Speed Aerodynamics Institute China Aerodynamics Research and Development CenterMianyang621000China

The reduced weight and improved efficiency of modern aeronautical structures result in a decreasing separation of frequency ranges of rigid and elastic ***,a high-aspect-ratio flexible flying wing is prone to body freedomflutter(BFF),which is a result of coupling of the rigid body short-periodmodewith 1st wing *** prediction of the BFF characteristics is helpful to reflect the attitude changes of the vehicle intuitively and design the active flutter suppression control *** of using the rigid body mode,this work simulates the rigid bodymotion of the model by using the six-degree-of-freedom(6DOF)equation.A dynamicmesh generation strategy particularly suitable for BFF simulation of free flying aircraft is *** accurate Computational Fluid Dynamics/Computational Structural Dynamics/six-degree-of-freedom equation(CFD/CSD/6DOF)-based BFF prediction method is ***,the time-domain CFD/CSD method is used to calculate the static equilibrium state of the *** on this state,the CFD/CSD/6DOF equation is solved in time domain to evaluate the structural response of *** combinedwith the variable stiffnessmethod,the critical flutter point of the model is *** method is applied to the BFF calculation of a flyingwing *** calculation results of the BFF characteristics of the model agree well with those fromthe modalmethod andNastran ***,the method is used to analyze the influence factors of *** analysis results show that the flutter speed can be improved by either releasing plunge constraint or moving the center ofmass forward or increasing the pitch inertia.

关键词： Body freedom flutter time-domain CFD/CSD/6DOF method dynamic mesh generation strategy aeroelasticity

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Tectonic Evolution and Lithospheric Structure of the Beishan Orogen: Insights from Magnetotelluric Studies

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Acta Geologica Sinica(English Edition) 2024年第S1期 6-9页

作者： CHEN Chutong ZHU Keying lyu binbin ZHANG Lingxiao YUAN Weiheng WANG Bin GUO Chang'an Center for Geophysical Survey China Geological Survey Technology Innovation Center for Earth Near Surface Detection China Geological Survey Langfang

The Beishan orogen, located in the central segment of the Tianshan–Solonker suture within the southern Central Asian Orogenic Belt(CAOB), is crucial for understanding the accretionary processes and continental growth in Central Asia. This orogen developed through the episodic amalgamation and accretion of continental margin arcs, island arcs, ophiolites, and accretionary wedges, undergoing a complex process of accretion and evolution. Since the Phanerozoic, the Beishan orogen has experienced multiple phases of magmatic and collision events. The intricate distribution of magmatic arc rocks has obscured the complete basement traces, and the spatial superposition of multiple magmatic arc phases has complicated the study of its evolutionary history.

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CFD/CSD-based flutter prediction method for experimental models in a transonic wind tunnel with porous wall

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Chinese Journal of Aeronautics 2020年第12期33卷 3100-3111页

作者： Tongqing GUO Daixiao LU Zhiliang LU Di ZHOU binbin lyu Jiangpeng WU Key Laboratory of Unsteady Aerodynamics and Flow Control Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016China China Aerodynamics Research and Development Center Mianyang 621000China Shenyang Aircraft Design and Research Institute Shenyang 110035China

To predict the flutter dynamic pressure of a wind tunnel model before flutter test,an accurate Computational Fluid Dynamics/Computational Structural Dynamics(CFD/CSD)-based flutter prediction method is proposed under the conditions of a 2.4 m×2.4 m transonic wind tunnel with porous *** the CFD simulations of the flows through an inclined hole of this wind tunnel,the Nambu's linear porous wall model between the flow rate and the differential pressure is extended to the porous wall with inclined holes,so that the porous wall can be conveniently modeled as a boundary *** to the flutter testing approach for the current wind tunnel,the steady CFD calculation is conducted to achieve the required inlet Mach number.A timedomain CFD/CSD method is then employed to evaluate the structural response of the experimental model,and the critical flutter point is obtained by increasing the dynamic pressure step by step at a fixed Mach *** present method is applied to the flutter calculations for a vertical tail model and an aircraft model tested in the current transonic wind *** both models,the computed flutter characteristics agree well with the experimental results.

关键词： CFD/CSD Experimental models Flutter Porous wall Transonic wind tunnel

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False Negative Sample Detection for Graph Contrastive Learning

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Tsinghua Science and Technology 2024年第2期29卷 529-542页

作者： binbin Zhang Li Wang College of Data Science Taiyuan University of TechnologyJinzhong 030600China

Recently,self-supervised learning has shown great potential in Graph Neural Networks (GNNs) through contrastive learning,which aims to learn discriminative features for each node without label information. The key to graph contrastive learning is data augmentation. The anchor node regards its augmented samples as positive samples,and the rest of the samples are regarded as negative samples,some of which may be positive samples. We call these mislabeled samples as “false negative” samples,which will seriously affect the final learning effect. Since such semantically similar samples are ubiquitous in the graph,the problem of false negative samples is very significant. To address this issue,the paper proposes a novel model,False negative sample Detection for Graph Contrastive Learning (FD4GCL),which uses attribute and structure-aware to detect false negative samples. Experimental results on seven datasets show that FD4GCL outperforms the state-of-the-art baselines and even exceeds several supervised methods.

关键词： graph representation learning contrastive learning false negative sample detection

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CircMYBL2 facilitates hepatocellular carcinoma progression by regulating E2F1 expression

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Oncology Research 2024年第6期32卷 1129-1139页

作者： JUNZHE YI binbin LI XIAOMIN YIN LINGRUI LIU CAILU SONG YING ZHAO MANBO CAI HAILIN TANG DONG CHEN NING lyu State Key Laboratory of Oncology in South China Guangdong Provincial Clinical Research Center for CancerSun Yat-sen University Cancer CenterGuangzhou510060China Department of Medical Oncology The Third People’s Hospital of YongzhouYongzhou425000China Department of Radiotherapy The First Affiliated HospitalHengyang Medical SchoolUniversity of South ChinaHengyang421001China Center of Hepato-Pancreato-Biliary Surgery The First Affiliated HospitalSun Yat-sen UniversityGuangzhou510080China

Circular RNAs(circRNAs)have been recognized as pivotal regulators in tumorigenesis,yet the biological functions as well as molecular mechanisms of the majority of circRNAs in hepatocellular carcinoma(HCC)remain *** sought to unveil the expression profile and biological role of circMYBL2 in *** microarray analyses were conducted to probe the expression profile of circMYBL2 in HCC cells,and qRT‒PCR analysis was then performed in HCC cell lines and tissues,revealing significant upregulation of *** experiments were conducted to evaluate the biological function of circMYBL2 in HCC ***,bioinformatics analysis,qRT‒PCR analysis,luciferase reporter assays,and western blot analysis were employed to investigate the interplay among circMYBL2,miR-1205,and ***2 was found to exhibit marked upregulation in tumor tissues as well as HCC cell *** expression of circMYBL2 increased the proliferation and migration of HCC cells,whereas circMYBL2 knockdown elicited contrasting ***,our results indicated that circMYBL2 promoted E2F1 expression and facilitated HCC progression by sponging *** findings revealed that circMYBL2 contributed to HCC progression through the circMYBL2/miR-1205/E2F1 axis,suggesting the potential of circMYBL2 as a novel target for HCC treatment or a prognostic biomarker for HCC.

关键词： Circular RNAs circMYBL2 miR-1205 E2F1 Hepatocellular carcinoma

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Immersive visualization of 3D subsurface ground model developed from sparse boreholes using virtual reality(VR)

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Underground Space 2024年第4期17卷 188-206页

作者： Borui lyu Yu Wang Department of Architecture and Civil Engineering City University of Hong KongKowloon 999077Hong KongChina

Analytics and visualization of multi-dimensional and complex geo-data,such as three-dimensional(3D)subsurface ground models,is critical for development of underground space and design and construction of underground structures(e.g.,tunnels,dams,and slopes)in engineering *** complicated 3D subsurface ground models now can be developed from site investigation data(e.g.,boreholes)which is often sparse in practice,it remains a great challenge to visualize a 3D subsurface ground model with sophisticated stratigraphic variations by conventional two-dimensional(2D)geological *** reality(VR)technology,which has an attractive capability of constructing a virtual environment that links to the physical world,has been rapidly developed and applied to visualization in various disciplines *** on the rapid development of VR,this study proposes a framework for immersive visualization of 3D subsurface ground models in geo-applications using VR *** 3D subsurface model is first developed from limited borehole data in a data-driven ***,a VR system is developed using related software and hardware devices currently available in the markets for immersive visualization and interaction with the developed 3D subsurface ground *** results demonstrate that VR visualization of the 3D subsurface ground model in an immersive environment has great potential in revolutionizing the geo-practices from 2D cross-sections to a 3D immersive virtual environment in digital era,particularly for the emerging digital twins.

关键词： Immersive visualization 3D subsurface model Virtual reality Virtual environment Interaction

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Macro-micro behaviors and failure mechanism of frozen weakly cemented mudstone

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1337-1347页

作者： Xianzhou lyu Jijie Du Hao Fu Dawei lyu Weiming Wang College of Earth Science and Engineering Shandong University of Science and TechnologyQingdao266590China College of Civil Engineering and Architecture Shandong University of Science and TechnologyQingdao266590China

Understanding the mechanical properties and multiscale failure mechanism of frozen soft rock is an important prerequisite for the construction safety of tunnels,artificially frozen ground and other infrastructure in cold *** this study,the triaxial compression test are performed on mudstone in the weakly cemented soft rock strata in the mining area of western China,and the mechanical characteristics and failure mechanism of weakly cemented mudstone are systematically investigated under the combined action of freezing and ***,the quantitative relationship between the microstructural parameters and the macroscopic strength and deformation parameters is established based on fractal ***,the failure mechanism of frozen weakly cemented mudstone is revealed on both micro- and *** results show that temperature and confining pressure significantly affects the elastic modulus and peak strength of weakly cemented *** decreasing temperature,the compressive strength increases,while the corresponding peak strain decreases *** the deformation curve,the plastic deformation stage is shortened,and the brittle fracture feature at the post-peak stage is more prominent,and the elastic modulus correspondingly increases with decreasing *** low-temperature conditions,most of the weakly cemented mudstone undergoes microscopic shear failure along the main fracture *** micro-fracture morphology characteristics of weakly cemented mudstone under different temperatures are quantified via the fractal dimension,and an approximately exponential relationship can be obtained among the fractal dimension and the temperature,compressive strength and elastic modulus.

关键词： Weakly cemented mudstone Artificial freezing Mechanical properties Linkage destruction mechanism Fractal dimension

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Perspective for OER electrocatalysts:Lattice engineering of clay-like frameworks with near-surface cluster active sites

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Science China(Technological Sciences) 2024年第1期67卷 330-334页

作者： ZHANG DanTong QIAN binbin XUE DongFeng Multiscale Crystal Materials Research Center Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China

Near-surface cluster active centers(NSCAC)are pivotal functional units in the catalysis of oxygen evolution reaction(OER),which exceeds the limitations imposed by the diverse coordination environments experienced in atomic and molecular active centers,thereby serving as an exceptional medium for exploring the dynamic catalytic processes of metal active sites[1,2].In the OER,the NSCAC primarily consist of the catalytic site and the first neighboring coordinating *** investigation of NSCAC surpasses the exclusive reliance on the electron state regulation mechanism at the atomic level.

关键词： cluster centers exceptional

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Model-based investigation on building thermal mass utilization and flexibility enhancement of air conditioning loads

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Building Simulation 2024年第8期17卷 1289-1308页

作者： Yue Sun Tianyi Zhao Shan lyu Institute of Building Energy School of Infrastructure EngineeringDalian University of TechnologyDalian116024China School of Civil Engineering Chongqing UniversityChongqing 400045China

Building air conditioning systems(ACs)can contribute to the stable operation of power grids by participating in peak load shaving programs,but the participants need a fast and accurate zone temperature prediction model,e.g.,the detailed room thermal-resistance(RC)model,to improve peak shaving effect and avoid obvious thermal ***,when applying the detailed room RC model to multi-zone buildings,conventional studies mostly consider the heat transfer among neighboring rooms,which contributes little to the prediction accuracy improvement,but leads to complicated model structure and heavy ***,a distributed RC model is developed for multi-zone buildings in this *** to conventional models,the proposed model considers the total heat transfer between the building and the air,and ignores the heat transfer among indoor air in neighboring rooms through internal walls with heavy thermal mass,thereby having comparable temperature prediction accuracy,simpler structure,and stronger *** on the model,the effectiveness of passive pre-cooling strategies in reducing the air conditioning loads during peak periods is *** indicate that the thermal insulation performance of opaque building envelope is quite important to the flexibility enhancement of air conditioning *** an uninsulated building envelope,passive pre-cooling is useless for the peak load *** comparison,well insulated opaque building envelope enables the building thermal mass to be utilized through passive pre-cooling,which leads to the air conditioning loads during peak periods being further reduced by about 12%.

关键词： RC model passive pre-cooling internal thermal mass building energy flexibility

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Amorphous hybrid tungsten oxide–nickel hydroxide nanosheets used as a highly efficient electrocatalyst for hydrogen evolution reaction

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Nano Research 2024年第4期17卷 2499-2508页

作者： Chao lyu Chenghai Dai Yiwei Tan State Key Laboratory of Materials-Oriented Chemical Engineering School of Chemistry and Chemical EngineeringNanjing Tech UniversityNanjing 211816China

There are more challenges for alkaline hydrogen evolution reaction(HER)via simultaneously expediting the electron-coupled water dissociation process(Volmer step)and the following electrochemical H_(2) desorption(Heyrovsky step).Hybrid amorphous electrocatalysts are highly desirable for efficient hydrogen evolution from water-alkali electrolyzers due to the bifunctionality for the different elementary steps of HER and optimal interactions with water molecules and the reactive hydrogen intermediates(Had).Herein,the synthesis of amorphous hybrid ultrathin(tungsten oxide/nickel hydroxide)hydrate(a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O)nanosheets on nickel foam(NF)for efficient alkaline HER is *** structural and composition features of a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O are characterized in *** resulting a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O/NF electrocatalyst with the synergistic effect of both hybrid components for the HER elementary steps shows greatly improved the activity and durability for the HER with a low overpotential of-41 and-163 mV at-10 and-500 mA·cm^(-2),respectively,a Tafel slope as low as-72.9 mV·dec^(-1),and long-term stability of continuous electrolysis for at least 150 h accompanying by inappreciable overpotential change in 1 M *** the hybrid a-[WO_(3)/Ni(OH)_(2)]·0.2H_(2)O,Ni(OH)_(2) and WO_(3) moieties are separately responsible for accelerating dissociative adsorption of water and weakening Had adsorption strength,which is beneficial to the improvement of the alkaline HER activity.

关键词： amorphous nanomaterial bimetallic electrocatalyst tungsten oxide ultrathin nanosheet hydrogen evolution reaction

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