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CES Transactions on Electrical Machines and Systems 2024年第1期8卷 12-21页

作者： Prabhakaran Koothu Kesavan Umashankar Subramaniam Dhafer j.Almakhles IEEE Renewable Energy Laboratory Department of Electrical EngineeringPrince Sultan UniversityRiyadh 12435Saudi Arabia

This paper,evaluate the effectiveness of a proposed speed loop pseudo derivative feedforward(PDFF)controller-based direct torque controller(DTC)for a PMSM drive against the performance of existing PI speed controller-based DTC and hysteresis current controller(HCC).The proposed PDFF-based speed regulator effectively reduces oscillation and overshoot associated with rotor angular speed,electromagnetic torque,and stator *** case studies,one using forward-to-reverse motoring operation and the other involving reverse-to-forward braking operation,has been validated to show the effectiveness of the proposed control *** proposed controller's superior performance is demonstrated through experimental verification utilizing an FPGA controller for a 1.5 kW PMSM drive laboratory prototype.

关键词： Direct torque control Pseudo derivative feedforward controller Permanent magnet synchronous motor(PMSM)

Mathematical modelling of ball and plate system with experimental and correlation function-based model validation

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Control Theory and Technology 2024年第2期22卷 326-341页

作者： T.R.Dil Kumar S.j.Mija Department of Electrical Engineering National Institute of Technology CalicutKozhikode673601KeralaIndia

The ball and plate system is an inherently nonlinear under actuated benchmark system used for validating the performance of various control schemes. A mathematical model depicting the dynamics close to that of the system is very much required for such a test bed. In this correspondence, the complete nonlinear model, a simplified nonlinear model, and a linearized model of the ball and plate system are developed. The system comprises a ball and plate mechanism and a rotary servo unit. The ball and plate mechanism is modelled using the Euler–Lagrange method, whereas the rotary servo subsystem is modelled from the first principles. The nonlinear model of the combined system is developed by including the dynamics of the servo motor with gear and rolling resistance between the ball and the plate. The simplified nonlinear model of the system is obtained with suitable assumptions. The model is linearized around the operating point using the jacobian. The validity of the developed models is investigated through correlation function analysis. The open-loop response of the three models, viz., nonlinear, simplified nonlinear, and linearized models, is analyzed in the MATLAB/Simulink platform. Since the open-loop system is unstable, the experimental validation of the model is performed with a double-loop PSO (particle swarm optimization) PID control scheme.

关键词： Ball and plate system Correlation function Model validation Particle swarm optimization(PSO) PSO PID controller

A Tutorial Review of the Solar Power Curve: Regressions, Model chains, and Their Hybridization and Probabilistic Extensions

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Advances in Atmospheric Sciences 2024年第6期41卷 1023-1067页

作者： Dazhi YANG Xiang’ao XIA Martin jános MAYER School of Electrical Engineering and Automation Harbin Institute of TechnologyHarbin 150001HeilongjiangChina Key Laboratory for Middle Atmosphere and Global Environment Observation(LAGEO) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Department of Energy Engineering Faculty of Mechanical EngineeringBudapest University of Technology and EconomicsMűegyetem rkp.3Budapest H-1111Hungary

Owing to the persisting hype in pushing toward global carbon neutrality,the study scope of atmospheric science is rapidly *** numerous trending topics,energy meteorology has been attracting the most attention *** essential skill of solar energy meteorologists is solar power curve modeling,which seeks to map irradiance and auxiliary weather variables to solar power,by statistical and/or physical *** this regard,this tutorial review aims to deliver a complete overview of those fundamental scientific and engineering principles pertaining to the solar power *** power curves can be modeled in two primary ways,one of regression and the other of model *** classes of modeling approaches,alongside their hybridization and probabilistic extensions,which allow accuracy improvement and uncertainty quantification,are scrutinized and contrasted thoroughly in this review.

关键词： review energy meteorology solar power curve model chain solar power prediction

Dissociation cross sections ofψ(3770),ψ(4040),ψ(4160),andψ(4415)mesons with nucleons

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Communications in Theoretical Physics 2024年第4期76卷 93-112页

作者： Ruo-Qing Ding Xiao-Ming Xu H j Weber Department of Physics Shanghai UniversityBaoshanShanghai 200444China Department of Physics University of VirginiaCharlottesvilleVA 22904United States of America

We study the dissociation of ψ(3770), ψ(4040), ψ(4160), and ψ(4415) mesons in collision with nucleons, which takes place in high-energy proton-nucleus collisions. The quark interchange between a nucleon and a ■ meson leads to the dissociation of the ■ meson. We consider the reactions:■, and■, where R stands for ψ(3770), ψ(4040), ψ(4160), or ψ(4415). A reaction of a neutron and a ■ meson corresponds to a reaction of a proton and the ■ meson by replacing the up quark with the down quark and vice versa. Transition-amplitude formulas are derived from the S-matrix *** cross sections are calculated with the transition amplitudes for scattering in the prior form and in the post form. The cross sections relate to nodes in the radial wave functions of ψ(3770), ψ(4040), ψ(4160), and ψ(4415) mesons.

关键词： inelastic nucleon-charmonium scattering quark interchange relativistic constituent quark potential model

Blood-brain barrier pathology in cerebral small vessel disease

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Neural Regeneration Research 2024年第6期19卷 1233-1240页

作者： Ruxue jia Gemma Solé-Guardia Amanda j.Kiliaan Department of Medical Imaging Anatomy Radboud University Medical Center Donders Institute for Brain Cognition & Behavior Center for Medical Neuroscience Preclinical Imaging Center PRIME Radboud Alzheimer Center

Cerebral small vessel disease is a neurological disease that affects the brain microvasculature and which is commonly observed among the elderly. Although at first it was considered innocuous, small vessel disease is nowadays regarded as one of the major vascular causes of dementia. Radiological signs of small vessel disease include small subcortical infarcts, white matter magnetic resonance imaging hyperintensities, lacunes, enlarged perivascular spaces, cerebral microbleeds, and brain atrophy; however, great heterogeneity in clinical symptoms is observed in small vessel disease patients. The pathophysiology of these lesions has been linked to multiple processes, such as hypoperfusion, defective cerebrovascular reactivity, and blood-brain barrier dysfunction. Notably, studies on small vessel disease suggest that blood-brain barrier dysfunction is among the earliest mechanisms in small vessel disease and might contribute to the development of the hallmarks of small vessel disease. Therefore, the purpose of this review is to provide a new foundation in the study of small vessel disease pathology. First, we discuss the main structural domains and functions of the blood-brain barrier. Secondly, we review the most recent evidence on blood-brain barrier dysfunction linked to small vessel disease. Finally, we conclude with a discussion on future perspectives and propose potential treatment targets and interventions.

关键词： blood-brain barrier dysfunction cerebral blood flow cerebral hypoperfusion endothelial dysfunction hypertension inflammation magnetic resonance imaging neurovascular unit oxidative stress small vessel disease tight junctions transcytosis

Structural and corrosion characterization of biodegradable Mg-RE (RE=Gd, Y, Nd) alloys

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Transactions of Nonferrous Metals Society of china 2013年第5期23卷 1215-1225页

作者： j.KUBSEK D.VOjTěch Department of Metals and Corrosion Engineering Institute of Chemical Technology

Binary Mg-Gd （up to 5% Gd in mass fraction）, Mg-Nd （up to 9% Nd in mass fraction） and ternary Mg-Gd-Y （up to 5% Gd, 1% Y） alloys with precisely determined contents of cathodic impurities （Fe, Ni, Cu, Co） were studied. The alloys were studied in the as-cast state （cooling rate of 500 K/min） and after solution heat treatment （T4）. Structures were investigated by optical and scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction and glow discharge spectrometry. Structural investigation was completed by Vickers hardness measurements. Corrosion behavior in the simulated physiological solution （9 g/L NaCl） was assessed by immersion tests and potentiodynamic measurements. It was found that the structures of the as-cast alloys were dominated by fine a-Mg dendrites and eutectic Mg-RE phases. The dendrites exhibited RE-concentration gradients which were most pronounced in the Mg-Gd alloys. For this reason, the T4 heat treatment of the Mg-Gd alloy led to the formation of a new cuboidal Mg5Gd phase. The corrosion resistance was significantly improved by Gd. The effect of Nd was weak and the addition of Y to Mg-Gd alloys had harmful effect on the corrosion resistance. The T4 heat treatment strongly accelerated the corrosion of Mg-Gd alloys. Its effect on the corrosion of Mg-Nd alloys was not significant. The observed corrosion behavior of the alloys was discussed in relation to their structural states and contents of cathodic impurities.

关键词： biodegradable material magnesium rare earths Mg-RE alloy structure corrosion

Lattice Boltzmann method formulation for simulation of thermal radiation effects on non-Newtonian Al_(2)O_(3) free convection in entropy determination

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 1085-1106页

作者： M.NEMATI M.SEFID A.KARIMIPOUR A.j.chAMKHA Faculty of Mechanical Engineering Yazd UniversityYazd ***Iran Department of Mechanical Engineering Najafabad BranchIslamic Azad UniversityNajafabad ***Iran Faculty of Engineering Kuwait College of Science and TechnologyDoha 35004Kuwait

The simultaneous investigation on the parameters affecting the flow of electrically conductive fluids such as volumetric radiation,heat absorption,heat generation,and magnetic field(MF)is very vital due to its existence in various sectors of industry and *** present research focuses on mathematical modeling to simulate the cooling of a hot component through power-law(PL)nanofluid convection *** temperature reduction of the hot component inside a two-dimensional(2D)inclined chamber with two different cold wall shapes is *** formulation of the problem is derived with the lattice Boltzmann method(LBM)by code writing via the FORTRAN *** variables such as the radiation parameter(0–1),the Hartmann number(0–75),the heat absorption/generation coefficient(−5–5),the fluid behavioral index(0.8–1.2),the Rayleigh number(103–105),the imposed MF angle(0°–90°),the chamber inclination angle(−90°–90°),and the cavity cold wall shape(smooth and curved)are *** findings indicate that the presence of radiation increases the mean Nusselt number value for the shear-thickening,Newtonian,and shear thinning fluids by about 6.2%,4%,and 2%,*** most cases,the presence of nanoparticles improves the heat transfer(HT)rate,especially in the cases where thermal conduction dominates *** is the lowest cooling performance index and MF effect for the cavity placed at an angle of 90°.The application in the design of electronic coolers and solar collectors is one of the practical cases of this numerical research.

关键词： thermal performance analysis heat absorption/generation power-law(PL)Al_(2)O_(3)nanofluid magnetohydrodynamics natural convection volumetric radiation inclined cavity

Thermo-kinetic characteristics on stabilizing hetero-phase interface of metal matrix composites by crystal plasticity finite element method

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journal of Materials Science & Technology 2024年第2期169卷 53-67页

作者： Y.B.Zhang S.j.Song F.Liu State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Analytical&Testing Center Northwestern Polytechnical UniversityXi’an 710072China

Using dislocation-based constitutive modeling in three-dimension crystal plasticity finite element(3D CPFE)simulations,co-deformation and instability of hetero-phase interface in different material systems were herein studied for polycrystalline metal matrix composites(MMCs).Local stress and strain fields in two types of 3layer MMCs such as fcc/fcc Cu-Ag and fcc/bcc Cu-Nb have been predicted under simple compressive ***,more severe strain-induced interface instability can be observed in the fcc/bcc systems than in the fcc/fcc systems upon refining to metallic nanolayered composites(MNCs).By detailed analysis of stress and strain localization,it has been demonstrated that the interface instability is always accompanied by high-stress concentration,i.e.,thermodynamic characteristics,or high strain prevention i.e.,kinetic characteristics,at the hetero-phase *** then follows that the thermodynamic driving forceG and the kinetic energy barrier Q during dislocation and shear banding can be adopted to classify the deformation modes,following the so-called thermo-kinetic *** by inserting a high density of high-energy interfaces into the Cu-Nb composites,such thermo-kinetic integration at the hetero-phase interface allows a successful establishment of MMCs with the high△G-high Q deformation mode,which ensures high hardening and uniform strain distri-bution,thus efficiently suppressing the shear band,stabilizing the hetero-phase interface,and obtaining an exceptional combination in strength and *** hetero-phase interface chosen by a couple of thermodynamics and kinetics can be defined as breaking the thermo-kinetic correlation and has been proposed for artificially designing MNCs.

关键词： Thermodynamics and kinetics Physics-based constitutive modeling Hetero-phase interface Crystal plasticity finite element

Stand dynamics of old-growth hemlock forests in central Bhutan are shaped by natural disturbances

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Forest Ecosystems 2024年第4期11卷 434-447页

作者： Karma Tenzin Craig R.Nitschke Kathryn j.Allen Raphael Trouve Thiet V.Nguyen Patrick j.Baker School of Agriculture Foodand Ecosystem SciencesUniversity of Melbourne500 Yarra BlvdRichmondVictoriaAustralia School of Geography Planningand Spatial SciencesUniversity of TasmaniaSandy BayTasmaniaAustralia Forest Science Institute of South Vietnam 1 Pham Van Hai StreetTan Binh DistrictHo Chi Minh CityViet Nam

Understanding how past disturbances have influenced the development of forests is critical for deciphering their current structure and composition and forecasting future *** this study,dendrochronological methods were applied to uncover the disturbance history of old-growth hemlock-dominated forests in central *** of tree-ring samples from two old-growth hemlock stands,located in two different topographic settings,identified the importance of gap-phase dynamics in facilitating recruitment and growth releases and producing complex,multi-aged structure s over *** site showed evidence of a near stand-replacing disturbance in the late 1700s,while the other showed no evide nce of high-severity disturbance at any time over the last 400 *** both sites low-to medium-severity disturbances,some of which appear to be associated with cyclones originating in the Bay of Bengal,dominated the disturbance *** hemlock stands exhibited a significant positive association between cyclone occurrence and growth release events and between recruitment pulses and growth release *** 1800 to 1970 there was an increase in recruitment of angiosperm tree species at most sites and a corresponding decline in conifer *** the past 50 years there has been little new recruitment;this may be due to light limitation in the understory from shade-tolerant angiosperms and bamboo in the lower strata of these *** variations in disturbance dynamics and recruitment were observed across the study sites,suggesting that other factors,such as topography and climate,may be influencing long-term stand development *** study highlights the complex interplay between historical disturbance regimes and tree recruitment in shaping the age and size structures of old-growth hemlock forests in central *** also provides new insights into the dynamics of these forests that can be used to support effective forest conservation and management i

关键词： Forest structure Hemlock forest Himalaya Natural disturbance

Magnetic filtration of an iron oxide aerosol by means of magnetizable grates

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china Particuology 2007年第1期5卷 140-144页

作者： A. Alvaro j.M. Rodríguez Paulo A. Augusto A.M. Estvez Department of chemical Engineering University of Salamanca Plaza de los Caídos 1-5 37008 Salamanca Spain Department of chemical Engineering University of Salamanca Plaza de los Caídos 1-5 37008 Salamanca Spain Department of Chemical Engineering Faculty of Engineering University of Porto Rua Dr. Roberto Frias 4200-465 Porto Portugal

The cleaning of gases with low concentrations of small ferromagnetic or paramagnetic particles is a difficult task for conventional filtration. A new alternative procedure, magnetic filtration, is used in this work. Iron oxide aerosol was generated by elutriation of iron oxide particles from a fluidized bed consisting of a mixture of Geldart-C iron oxide powder and large spherical Geldart-B sand particles. The aerosol was filtered by means of a magnetic filter which consisted of one, two or three iron grates staggered to each other. The experimental installation contained also an isokinetic sampling system and a Microtrac SRA 150 Particle Analyser. A theoretical expression for filtration efficiency was deduced from a previous model taking into account the different forces acting on the iron oxide particles. Experimental filtration efficiency matches quite well calculated theoretical efficiency. It was found that an increase in particle size, in thee number of grates or in the applied magnetic field produced higher filtration efficiencies up to 100% in some cases. In all filtration experiments pressure drop through the magnetic filter was very small.

关键词： Iron oxide aerosol Magnetic filtration Iron grates