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Topology of nuclear reaction networks of interest for astrophysics

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Science China(Physics,Mechanics & Astronomy) 2020年第11期63卷 10-11页

作者： carlos ABertulani Department of Physics and Astronomy Texas A&M University-CommerceCommerce TX 75429USA

Our understanding of the observed elemental abundance in the universe,stemming from nuclear reactions during the big bang or from nucleosynthesis within stellar environments,requires theoretical analyses based on multidimensional nucleosynthesis calculations involving hundreds of nuclei connected via thousands of nuclear *** to recently,full nucleosynthesis network calculations remained computationally expensive and prohibitive.

关键词： nucleosynthesis universe environments

Theranostic of orthotopic gliomas by core-shell structured nanoplatforms

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Light(Science & Applications) 2022年第6期11卷 1034-1035页

作者： Luis D.carlos Phantom-G CICECO-Aveiro Institute of MaterialsPhysics DepartmentUniversity of Aveiro3810-193 AveiroPortugal

Smart designed core-shell nanostructures formed by a YVO_(4)∶Nd^(3+) nanoparticle as the core,the sonosensitizer hematoporphyrinmonomethyl ether as the carrier,and MnO_(2) nanosheets as the shell demonstrate bimodal ... 详细信息

关键词： modal glioma orthotopic

Impact of seismic design on tunnels in rock-Case histories

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Underground Space 2017年第2期2卷 106-114页

作者： carlos A.Jaramillo COWI North America 1300 Clay Street7th FloorOaklandCA 94612USA

The tunnel industry has considered that tunnels,especially tunnels in rock,are naturally resistant to earthquake action,including faulting,shaking,deflection and ground *** the number of case histories of tunnels subject to earthquake action has increased,the industry has started to recognize that,although tunnels in rock have good resistance against earthquakes generating peak ground accelerations(PGA)lower than 0.5 g,it is important to include the dynamic forces and displacements generated by seismic ground motions in the design process to obtain a more reliable *** additional earthquake forces impact the final design,potentially requiring changes to the ground support and additional reinforcement of the concrete lining,as illustrated by case histories presented in this paper.

关键词： Tunnel Tunnels Seismic design Earthquake impact Tunnel lining Ground support

Mass-Stiffness Templates for Cubic Structural Elements Dedicated to Professor Karl Stark Pister for his 95th birthday

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Computer Modeling in Engineering & Sciences 2021年第12期129卷 1209-1241页

作者： carlos A.Felippa Department of Aerospace Engineering Sciences and Aerospace Mechanics Research Center University of Colorado at BoulderBoulderCO 80309-0429USA

1 This paper considers Lagrangian finite elements for structural dynamics constructed with cubic displacement shape *** method of templates is used to investigate the construction of accurate mass-stiffness *** method introduces free parameters that can be adjusted to customize elements according to accuracy and rank-sufficiency ***-and two-dimensional Lagrangian cubic elements with only translational degrees of freedom(DOF)carry two additional nodes on each side,herein called side nodes or *** usually placed at the third-points,the SN location may be adjusted within geometric *** adjustment effect is studied in detail using symbolic computations for a bar *** best SN location is taken to be that producing accurate approximation to the lowest natural frequencies of the continuum *** is investigated through Fourier analysis of the propagation of plane waves over a regular infinite lattice of bar *** is placed on the acoustic branch of the frequency-vs.-wavenumber dispersion *** is found that dispersion results using the fully integrated consistent mass matrix(CMM)are independent of the SN location whereas its lowfrequency accuracy order is O(κ8),whereκis the dimensionless wave *** the diagonally lumped mass matrix(DLMM)constructed through the HRZ scheme,two optimal SN locations are identified,both away from third-points and of accuracy order O(κ8).That with the smallest error coefficient corresponds to the Lobatto 4-point integration rule.A special linear combination of CMM and DLMM with nodes at the Lobatto points yields an accuracy of O(κ10)without any increase in the computational effort over *** effect of reduced integration(RI)on both mass and stiffness matrices is also *** is shown that singular mass matrices can be constructed with 2-and 3-point RI rules that display the same optimal accuracy of the exactly integrated case,at the cost of introducing spurious modes

关键词： Structural dynamics Lagrangian elements finite elements cubic shape functions bar plane stress mass stiffness vibration wave propagation Fourier analysis dispersion templates

Stability analysis of the fluttering and autorotation of flow-induced rotation of a hinged flat plate

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Journal of Hydrodynamics 2013年第5期25卷 755-762页

作者： MIRZAEISEFAT Sina FERNANDES Antonio carlos Department of Naval Architecture and Marine Engineering University of Michigan COPPE/UFRJ Federal University of Rio de Janeiro

This work describes investigations performed on the interaction of uniform current and freely rotating plate about a fixed vertical axis. Fluttering and autorotation are two different motions that may occur during the flow induced rotation. The dimensional analysis proves that the motion in flow induced rotation motion is governed essentially by the dimensionless moment of inertia and Reynolds number. Certain combinations define the stability boundaries between fluttering and autorotation. Fluttering is oscillation of body about a vertical axis and the autorotation is a name given to the case when the body turns continuously about the vertical axis First, the loads and moment coefficients are calculated by experiments and streamline theory for different angles of attack for a fixed fiat plate. Then for dynamic case, a bifurcation diagram is presented based on experiments to classify different motion states of flow induced rotation. Finally, a dynamical model is proposed for stability analysis of flow induced rotation of a flat plate.

关键词： flow-induced rotation autorotation fluttering stability analysis

Phenomenological model for torsional galloping of an elastic flat plate due to hydrodynamic loads

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Journal of Hydrodynamics 2014年第1期26卷 57-65页

作者： FERNANDES Antonio carlos ARMANDEI Mohammadmehdi Department of Naval and Ocean Engineering COPPE/UFRJ

This study investigates the torsional galloping phenomenon, an instability type flow-induced oscillation, in an elastic stru-cture due to hydrodynamic loads into the water current. The structure applied here is a rectangular flat plate with an elastic axis in its mid-chord length. The elasticity is provided by torsion spring. The flat plate has only one degree of freedom which is rotation in pure yaw about its axis. It is observed that as the current speed is higher than a critical velocity, the flat plate becomes unstable. The instability leads to torsional galloping occurrence, as a result of which the flat plate begins to yaw about the elastic axis. By testing two different chord lengths each with several torsion spring rates, the flat plate behavior is investigated and three different responses are recognized. Then, a phenomenological model is developed with the original kernel in the form of the van der Pol-Duffing equa-tion. The model explains these three responses observed experimentally.

关键词： torsional galloping flow-induced oscillation phenomenological model van der Pol-Duffing equation

Optimal Positioning Strategy for Multi-Camera Zooming Drones

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IEEE/CAA Journal of Automatica Sinica 2024年第8期11卷 1802-1818页

作者： Manuel Vargas carlos Vivas Teodoro Alamo Department of System Engineering and Automation University of SevilleSeville 41092Spain

In the context of multiple-target tracking and surveillance applications,this paper investigates the challenge of determining the optimal positioning of a single autonomous aerial vehicle or agent equipped with multiple independently-steerable zooming cameras to effectively monitor a set of targets of *** camera is dedicated to tracking a specific target or cluster of *** key innovation of this study,in comparison to existing approaches,lies in incorporating the zooming factor for the onboard cameras into the optimization *** enhancement offers greater flexibility during mission execution by allowing the autonomous agent to adjust the focal lengths of the onboard cameras,in exchange for varying real-world distances to the corresponding targets,thereby providing additional degrees of freedom to the optimization *** proposed optimization framework aims to strike a balance among various factors,including distance to the targets,verticality of viewpoints,and the required focal length for each *** primary focus of this paper is to establish the theoretical groundwork for addressing the non-convex nature of the optimization problem arising from these *** this end,we develop an original convex approximation *** paper also includes simulations of diverse scenarios,featuring varying numbers of onboard tracking cameras and target motion profiles,to validate the effectiveness of the proposed approach.

关键词： Convex optimization projective transformation unmanned aerial vehicle visual object tracking visual surveillance.

Bresse Beam with Damping and Logarithmic Source

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Chinese Annals of Mathematics,Series B 2024年第5期45卷 685-702页

作者： Sebastiao CORDEIRO carlos BALDEZ carlos RAPOSO Ducival PEREIRA Octavio VERA Department of Mathematics Federal University of ParaAbaetetubaParaBrazil Department of Mathematics Federal University of ParaBragancaParaBrazil Department of Mathematics Federal University of ParaSalinopolisParaBrazil Department of Mathematics State University of ParaBelemParaBrazil Department of Mathematics University of TarapacaAricaChile

This paper investigates the stabilization of a Bresse system with internal damping and logarithmic *** authors use the potential well *** initial data in the stability set created by the Nehari surface,the existence of a global solution is proved by using Faedo-Galerkin's *** Nakao theorem gives the exponential decay.A numerical approach is presented to illustrate the results obtained.

关键词： Bresse beam Logarithmic source Global solution Exponential decay Numerical approach

Air Pollution, Government Pollution Regulation, and Industrial Production in China

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Journal of Systems Science & Complexity 2020年第4期33卷 1064-1079页

作者： CAO Dong RAMIREZ carlos D. School of Economics and Management Xidian UniversityXi’an 710071China Department of Economics George Mason UniversityFairfaxVAUnited States

Over the last four decades,a severe deterioration in air quality has accompanied China’s rapid *** a result,the Chinese government has implemented stricter policies and regulation to control air *** this paper,the authors create a measure of government policies on air pollution by tracking all pollution-related government announcements in Chinese *** authors then use this variable,along with measures of actual pollution,to investigate how air pollution,industrial production,and government policies on air pollution are *** authors conduct this investigation nationwide,as well as in five large cities in China.A vector autoregression model suggests that,nationwide,government policies seem to decrease air pollution without significantly affecting industrial ***,the effect appears to be short-lived,dissipating after a few *** addition,the authors find that the dynamic relationship among these variables differs by *** instance,following an adverse air quality shock in Beijing,government efforts to control pollution seem to have an ameliorating city-wide effect,decreasing local air pollution in subsequent *** Shanghai and Guangzhou,while the local government reacts to adverse air pollution shocks,the ameliorating effects are not statistically *** Chengdu and Shenyang,the authors detect no significant local government reaction to adverse air pollution ***,in these cities,local government policies do not impart a statistically measurable effect on air pollution.

关键词： pollution. pollution nationwide