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Numerical analysis of a magnetohydrodynamic duct flow with flow channel insert under a non-uniform magnetic field

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journal of Hydrodynamics 2018年第6期30卷 1134-1142页

作者： c.N.kim Department of Mechanical Engineering College of Engineering Kyung Hee University

This study performs a numerical analysis of three-dimensional liquid metal(LM) magnetohydrodynamic(MHD) flows in a square duct with an FcI in a non-uniform magnetic field. The current study predicts detailed information on flow velocity, Lorentz force, pressure, current and electric potential of MHD duct flows for different Hartmann numbers. Also, the effect of the electric conductivity of FcI on the pressure drop along the main flow direction in a non-uniform magnetic field is examined. The present study investigates the features of LM MHD flows in consideration of the interdependency among the flow variables.

关键词： Non-uniform magnetic field liquid metal blanket magnetohydrodynamic(MHD) duct flow flow channel insert

Estimation of premature forests in Georgia (USA) using *** Service FIA data and Landsat imagery

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journal of Forestry Research 2017年第6期28卷 1241-1252页

作者： Hojung kim chris j. cieszewski Roger c. Lowe Warnell School of Forestry and Natural Resources University of Georgia 180 E. Green Street AthensGA 30602 USA

We used geographic information system applications and statistical analyses to classify young, premature forest areas in southeastern Georgia using combined data from Landsat TM 5 satellite imagery and ground inventory data. We defined premature stands as forests with trees up to 15 years old. We estimated the premature forest areas using three methods: maximum likelihood classification(MLc), regression analysis, and k-nearest neighbor(k NN)modeling. Overall accuracy(OA) of classifying the premature forest using MLc was 82% and the Kappa coefficient of agreement was 0.63, which was the highest among the methods that we have tested. The k NN approach ranked second in accuracy with OA of 61% and a Kappa coefficient of agreement of 0.22. Regression analysis yielded an OA of 57% and a Kappa coefficient of 0.14. We conclude that Landsat imagery can be effectively used for estimating premature forest areas in combination with image processing classifiers such as MLc.

关键词： Landsat Maximum likelihood classification Regression analysis k-nearest neighbor

Vertically aligned NiS nano-flakes derived from hydrothermally prepared Ni(OH)2 for high performance supercapacitor

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journal of Energy chemistry 2018年第3期27卷 791-800页

作者： A.M.Patil A.c.Lokhande P.A.Shinde j.H.kim c.D.Lokhande Thin Film Physics Laboratory Department of PhysicsSbivaji UniversityKolbapar 416004 MHIndia Department of Materials Science and Engineering Chonnam National University 300 Yongbong-DongPuk-GuGwangju.South Korea centre for Interdisciplinaly Research D.Y.Patil UniversityKolhapurIndia

In present work,the vertically aligned Ni S nano-flakes composed thin film is prepared by anionic exchange process in which hydrothermally prepared Ni（OH）2is used as a parent thin film and Na2S as a sulfide ion *** synthesis process produced fully transformed and shape-controlled nano-flakes of Ni S from nano-flowers of Ni（OH）*** electrochemical supercapacitor properties of Ni S electrode are studied with cyclic voltammetry（cV）,galvonostatic charge discharge（GcD）and electrochemical impedance spectroscopy（EIS）*** porous surface area（85 m^2/g）of Ni S nano-flakes makes large material contribution in electrochemical reaction stretching specific capacitance（cs）of 880 F/g at scan rate of 5 m V/s and 90%electrochemical stability up to 4000 cV cycles in 2 M KOH ***,the flexible solid-state symmetric supercapacitor device（Ni S/PVA–Li clO4/Ni S）has been fabricated using Ni S electrodes with polyvinyl alcohol（PVA）–lithium perchlorate（Li clO4）gel *** Ni S/PVA–Li clO4/Ni S device exhibits specific capacitance of 56 F/g with specific energy of 14.98 Wh/kg and excellent cycling stability after 2000 *** addition,the Ni S/PVA–Li clO4/Ni S device demonstrates illumination of red light emitting diode（LED）for 60 s,which confirms the practical applicability of Ni S/PVA–Li clO4/Ni S device in energy storage.

关键词： Anionic exchange process Nickel sulfide Nano-flakes Supercapacitor Thin film

computational study on influence of RF shielding box on inductance of coil

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Plasma Science and Technology 2019年第6期21卷 23-28页

作者： S j kim j j LEE Y S LEE j H kim S j YOU Applied Physics lab for PLasma Engineering(APPLE) Department of Physics Chungnam National University Daejeon 34134 Republic of Korea Korea Research Institute of Standards and Science(KRISS) Daejeon 34113 Republic of Korea

Despite the fact that a radio frequency (RF) shielding box affects a coil inductance used in matching network,RF engineers have used a coil inductance measured in open space on designing matching networks since it is difficult to precisely measure the coil inductance within the RF shielding *** this work,we investigate the influences of the RF shielding box on the coil inductance via a 3D full electromagnetic wave *** results shows that the coil inductance decreases from-6.0% to-11.9% compared with its ideal inductance depending on coil positions within the RF shielding *** inductive and capacitive coupling between the coil and surfaces of the RF shielding box contribute to the reduction of the coil *** expect that these results would be useful for those who design RF matching networks.

关键词： 3D full EM wave simulation RF matching component RF shield inductive and capacitive coupling

Inflammasome links traumatic brain injury, chronic traumatic encephalopathy, and Alzheimer's disease

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Neural Regeneration Research 2025年第6期20卷 1644-1664页

作者： Gabriela Seplovich Yazan Bouchi juan Pablo de Rivero Vaccari jennifer c.Munoz Pareja Andrew Reisner Laura Blackwell Yehia Mechref Kevin K.Wang j.Adrian Tyndall Binu Tharakan Firas Kobeissy Department of Surgery Morehouse School of MedicineAtlantaGAUSA Department of Neurobiology Center for NeurotraumaMultiomics&Biomarkers(CNMB)Neuroscience InstituteMorehouse School of MedicineAtlantaGAUSA Department of Neurological Surgery and the Miami Project to cure Paralysis University of Miami Miller School of MedicineMiamiFLUSA Division of Pediatric critical care Department of PediatricsUniversity of Miami Miller School of MedicineMiamiFLUSA Department of Pediatrics Emory UniversityAtlantaGAUSA Department of Neurosurgery Children’s Healthcare of AtlantaAtlantaGAUSA Department of chemistry and Biochemistry Texas Tech UniversityLubbockTXUSA Morehouse School of Medicine AtlantaGAUSA

Traumatic brain injury, chronic traumatic encephalopathy, and Alzheimer's disease are three distinct neurological disorders that share common pathophysiological mechanisms involving neuroinflammation. One sequela of neuroinflammation includes the pathologic hyperphosphorylation of tau protein, an endogenous microtubule-associated protein that protects the integrity of neuronal cytoskeletons. Tau hyperphosphorylation results in protein misfolding and subsequent accumulation of tau tangles forming neurotoxic aggregates. These misfolded proteins are characteristic of traumatic brain injury, chronic traumatic encephalopathy, and Alzheimer's disease and can lead to downstream neuroinflammatory processes, including assembly and activation of the inflammasome complex. Inflammasomes refer to a family of multimeric protein units that, upon activation, release a cascade of signaling molecules resulting in caspase-induced cell death and inflammation mediated by the release of interleukin-1β cytokine. One specific inflammasome, the NOD-like receptor protein 3, has been proposed to be a key regulator of tau phosphorylation where it has been shown that prolonged NOD-like receptor protein 3 activation acts as a causal factor in pathological tau accumulation and spreading. This review begins by describing the epidemiology and pathophysiology of traumatic brain injury, chronic traumatic encephalopathy, and Alzheimer's disease. Next, we highlight neuroinflammation as an overriding theme and discuss the role of the NOD-like receptor protein 3 inflammasome in the formation of tau deposits and how such tauopathic entities spread throughout the brain. We then propose a novel framework linking traumatic brain injury, chronic traumatic encephalopathy, and Alzheimer's disease as inflammasomedependent pathologies that exist along a temporal continuum. Finally, we discuss potential therapeutic targets that may intercept this pathway and ultimately minimize long-term neurological decline.

关键词： Alzheimer's disease caspase-1 chronic traumatic encephalopathy inflammasomes neurodegeneration neuroinflammation NLRP1 NLRP3 pyroptosis tauopathy traumatic brain injury

Transient analysis of diffusive chemical reactive species for couple stress fluid flow over vertical cylinder

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Applied Mathematics and Mechanics(English Edition) 2013年第8期34卷 985-1000页

作者： H.P.RANI G.j.REDDY c.N.kim Department of Mathematics National Institute of Technology Department of Mechanical Engineering College of Advanced Technology (Industrial Liaison Research Institute) Kyung Hee University

The unsteady natural convective couple stress fluid flow over a semi-infinite vertical cylinder is analyzed for the homogeneous first-order chemical reaction effect. The couple stress fluid flow model introduces the length dependent effect based on the material constant and dynamic viscosity. Also, it introduces the biharmonic operator in the Navier-Stokes equations, which is absent in the case of Newtonian fluids. The solution to the time-dependent non-linear and coupled governing equations is carried out with an unconditionally stable crank-Nicolson type of numerical schemes. Numerical results for the transient flow variables, the average wall shear stress, the Nusselt number, and the Sherwood number are shown graphically for both generative and destructive reactions. The time to reach the temporal maximum increases as the reaction constant K increases. The average values of the wall shear stress and the heat transfer rate decrease as K increases, while increase with the increase in the Sherwood number.

关键词： couple stress fluid chemical reaction natural convection vertical cylinder,finite difference method

Plasma density measurement and downstream etching of silicon and silicon oxide in Ar/NF3 mixture remote plasma source

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Plasma Science and Technology 2019年第6期21卷 52-57页

作者： H j YEOM D H cHOI Y S LEE j H kim D j SEONG S j YOU H c LEE Korea Research Institute of Standards and Science(KRISS) Daejeon 34113 Republic of Korea Department of Physics Chungnam National University Daejeon 34134 Republic of Korea

In this study,plasma density measurements were performed near the plume region of the remote plasma source (RPS) in Ar/NF3 gas mixtures using a microwave cutoff *** measured plasma density is in the range of 1010-1011 cm-3 in the discharge conditions with RPS powers of 2-4 kW and gas pressures of 0.87-4 *** plasma density decreased with increasing gas pressures and RPS powers under various Ar/NF3 mixing *** decrease in the plasma density measured at the fixed measurement position (plume region) can be understood by the reduction of the electron energy relaxation length with increases in the gas pressures and mixing ratio of NF3/(Ar/NF3).We also performed downstream etching of silicon and silicon oxide films in this *** etch rate of the silicon films significantly increases while the silicon oxide is slightly etched with the gas pressures and *** was also found that the etch rate strongly depends on the wafer position on the processing chamber electrode,and that the etch selectivity reached 96-131 in the discharge conditions of RF powers (3730-4180 W) and gas pressures (3.6-4 Torr).

关键词： remote plasma source electron density cutoff probe downstream etch

Quantitative visualization of Taylor-couette flow with helical protrusion using optical and ultrasound imaging method

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排灌机械工程学报 2016年第10期34卷 829-834页

作者： kim S.j. TU X.c. kim H.B. School of Mechanical and Aerospace Engineering Gyeongsang National University Research center for Aircraft Parts Technology Gyeongsang National University

The simplified flow of drilling process in the soil hardening or oil rig site was experimentally investigated. Two flow models were used. One is the concentric cylinders with helical protrusion at the inner cylinder. The other is the concentric plain wall cylinders with axial flow. The radius ratio and aspect ratio of both models are the same with 0. 65 and 48,respectively. The mud is the typical fluid seen in the soil hardening processes. We used the water and the mud for the working fluid. We used the optical PIV for the water flow measurement and echo PIV for the mud flow. In case of the water study,the dominant vortical structures appeared in both the protrusion and plain model with axial *** case of mud flow,the vortices shown in the water model disappeared and the push and pull-up motion by the protrusion is dominant. We believe this information can be useful to understand the flow physics of drilling process in the complex fluid flow.

关键词： Taylor-couette flow surface protrusion echo PIV mud flow

Photoluminescence enhancement of red-emitting GdVO_4:Eu and YVO_4:Eu phosphors by adding zinc

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journal of Rare Earths 2013年第1期31卷 13-17页

作者： K.Park j.kim K.Y.kim j.Y.kim Y.kim S.j.Dhoble Faculty of Nanotechnology and Advanced Materials Engineering Sejong University Department of Advanced Materials Engineering Hoseo University Department of chemistry and Institute of Basic Sciences Dankook University Department of Physics R.T.M. Nagpur University

We synthesized the rare-earth activated Ro.94_xEuo.06ZnxVO4 （R： Gd and Y; 0〈_x〈_0.08） phosphors with a spherical mor- phology and a smooth surface by the ultrasonic spray pyrolysis. The annealed Ro.94_xEuo.06ZnxVO4 crystallized in the tetragonal zircon type structure, belonging to the space group of I41/amd. The incorporation of a small amount of Zn to Ro.94Euo.06VO4 improved the emission characteristics. The emission intensities of the Gdo.88EUo.06Zno.06VO4 and Yo.9Euo.06Zno.04VO4 phosphors at 619 nm were 72% and 2 1% stronger than those of the Gdo,94Euo.06VO4 and Yo.94Euo.06VO4 phosphors, respectively. We demonstrated that the addi- tion of Zn to Ro.94Euo.06VO4 was quite effective for improving the photoluminescent properties.

关键词： rare earths photolurninescence vanadate ultrasonic spray pyrolysis