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Broadband strong optical dichroism in topological Dirac semimetals with Fermi velocity anisotropy

Chinese Physics B 2020年第7期29卷 128-134页

作者： J lim k J A Ooi C Zhang L k Ang Yee Sin Ang Science Math and TechnologySingapore University of Technology and DesignSingapore School of Energy and Chemical Engineering Xiamen University MalaysiaSelangor Darul Ehsan 43900Malaysia College of Chemistry and Chemical Engineering Xiamen UniversityXiamen 361005China School of Physics University of WollongongNorthfields AvenueNew South Wales 2522Australia

Prototypical three-dimensional(3D)topological Dirac semimetals(DSMs),such as Cd3As2 and Na3Bi,contain electrons that obey a linear momentum-energy dispersion with different Fermi velocities along the three orthogonal momentum *** being extensively studied in recent years,the inherent Fermi velocity anisotropy has often been neglected in the theoretical and numerical studies of 3D *** this omission does not qualitatively alter the physics of light-driven massless quasiparticles in 3D DSMs,it does quantitatively change the optical coefficients which can lead to nontrivial implications in terms of nanophotonics and plasmonics *** we study the linear optical response of 3D DSMs for general Fermi velocity values along each *** the signature conductivity-frequency scaling,σ(ω)∝ω,of 3D Dirac fermion is well-protected from the Fermi velocity anisotropy,the linear optical response exhibits strong linear dichroism as captured by the universal extinction ratio scaling law,Λi j=(vi/v j)^2(where i=j denotes the three spatial coordinates x,y,z,and vi is the i-direction Fermi velocity),which is independent of frequency,temperature,doping,and carrier scattering *** Cd3As2 and Na3Bi3,an exceptionally strong extinction ratio larger than 15 and covering a broad terahertz window is *** findings shed new light on the role of Fermi velocity anisotropy in the optical response of Dirac semimetals and open up novel polarization-sensitive functionalities,such as photodetection and light modulation.

关键词： topological Dirac semimetal optical anisotropy linear dichroismn linear response theory

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AnAdaptive Moving Mesh Method for Two-Dimensional Incompressible Viscous Flows

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Communications in Computational Physics 2008年第3期3卷 679-703页

作者： Zhijun Tan k.M.lim B.C.khoo Singapore-MIT Alliance 4 Engineering Drive 3National University of SingaporeSingapore 117576Singapore Department of Mechanical Engineering National University of Singapore10 Kent Ridge CrescentSingapore 119260Singapore.

In this paper, we present an adaptive moving mesh technique for solvingthe incompressible viscous flows using the vorticity stream-function formulation. Themoving mesh strategy is based on the approach proposed by Li et al. [J. Comput. Phys.,170 (2001), pp. 562–588] to separate the mesh-moving and evolving PDE at each timestep. The Navier-Stokes equations are solved in the vorticity stream-function form bya finite-volume method in space, and the mesh-moving part is realized by solving theEuler-Lagrange equations to minimize a certain variation in conjunction with a moresophisticated monitor function. A conservative interpolation is used to redistributethe numerical solutions on the new meshes. This paper discusses the implementationof the periodic boundary conditions, where the physical domain is allowed to deformwith time while the computational domain remains fixed and regular throughout. Numericalresults demonstrate the accuracy and effectiveness of the proposed algorithm.

关键词： Moving mesh method finite volume method Navier-Stokes equations vorticity stream-function incompressible flow.

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An Implementation ofMAC Grid-Based IIM-Stokes Solver for Incompressible Two-Phase Flows

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Communications in Computational Physics 2011年第10期10卷 1333-1362页

作者： Zhijun Tan k.M.lim B.C.khoo Guangdong Province key Laboratory of Computational Science and School of Mathematics and Computational Science Sun Yat-sen UniversityGuangzhou 510275China Singapore-MIT Alliance 4 Engineering Drive 3National University of SingaporeSingapore 117576Singapore Department ofMechanical Engineering National University of Singapore10 Kent Ridge CrescentSingapore 119260Singapore

*** this paper,a novel implementation of immersed interface method combined with Stokes solver on a MAC staggered grid for solving the steady two-fluid Stokes equations with *** velocity components along the interface are introduced as two augmented variables and the resulting augmented equation is then solved by the GMrES *** augmented variables and/or the forces are related to the jumps in pressure and the jumps in the derivatives of both pressure and velocity,and are interpolated using cubic splines and are then applied to the fluid through the jump *** Stokes equations are discretized on a staggered Cartesian grid via a second order finite difference method and solved by the conjugate gradient *** numerical results show that the overall scheme is second order *** major advantages of the present IIM-Stokes solver are the efficiency and flexibility in terms of types of fluid flow and different boundary *** proposed method avoids solution of the pressure Poisson equation,and comparisons are made to show the advantages of time savings by the present *** generalized two-phase Stokes solver with correction terms has also been applied to incompressible two-phase Navier-Stokes flow.

关键词： Incompressible two-phase Stokes equations two-phaseNavier-Stokes equations discontinuous viscosity singular force immersed interface method Uzawa method front tracking method.

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robust color purity of reddish-orange emission from Sm^(3+)-activated La10W22O81 biocompatible microphosphors for solid state lighting and anticancer applications

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Journal of rare Earths 2023年第12期41卷 1850-1859,I0001页

作者： k.Naveen kumar L.Vijayalakshmi Gayeon Lee Gumin kang Jiseok lim Jungwook Choi School of Mechanical Engineering Yeungnam UniversityGyeongsanGyeongbuk38541Republic of Korea Department of Automotive Engineering Yeungnam UniversityGyeongsanGyeongbuk38541Republic of Korea School of Mechanical Engineering Chung-Ang UniversitySeoul06974Republic of Korea Nanophotonics research Center Korea Institute of Science and TechnologySeoul2792Republic of Kora

We synthesized reddish-orange luminescent La_(10)W_(22)O_(81)(LWO):Sm^(3+)microphosphors by hydrothermalassisted solid-state reaction.X-ray diffraction analysis reveals that all the studied phosphors crystallize in an orthorhombic structure in the Pbcn space group(60),Field emission scanning electron microscopy indicates that the LWO:1.5 mol% Sm^(3+)phosphor displays a smooth-surfaced hexagonal rod-like shape,with a closed shape at both ends,and high-resolution transmission electron microscopy demonstrates a robust crystalline *** chemical composition and valence states of the phosphor were investigated using X-ray photoelectron *** 403 nm excitation,LWO:1.5 mol% Sm3+exhibits maximum intensity with the strongest band at 596 nm(^(4)G_(5/2)→^(6)H_(7/2)) in the reddish-orange *** intensity of Sm^(3+) emission decreases beyond 1.5 mol% owing to concentration quenching regulated by dipole-quadrupole interaction between Sm^(3+)*** optimized microphosphor LWO:1.5 mol% Sm^(3+)exhibits color coordinates(0.5760,0.4207),which is close to that of the Amber LED-NSPAr 70 BS(0.570,0.420),displaying the highest color purity of 99.2% and correlated color temperature of 1694 *** addition,both breast cancer cells MCF-7 and normal lung fibroblasts WI-38 were tested for toxicity with the optimized *** is found that the LWO:1.5 Sm^(3+)microphosphor is extremely toxic to cancer cells,but not to normal *** on these results,LWO:Sm^(3+)microphosphor can serve as a biomedical candidate for the treatment of cancer,as well as a potential multicolor emitting material for w-LEDs.

关键词： Sm^(3+):La_(10)W_(22)O_(81) reddish-orangeemission Color purity Photonic applications Anticancer rareearths

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Landau damping of twisted waves in Cairns distribution with anisotropic temperature

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Plasma Science and Technology 2021年第8期23卷 18-28页

作者： Sunggeun LEE Hankwon lim School of Energy and Chemical Engineering UNIST50UNIST-gilEonyang-eupUlju-gunUlsan 44919Republic of Korea

The consideration of orbital angular momentum of an electric field(twisted mode)is applied to the kinetic theory of *** linearized Vlasov–Poisson equation is solved for the anisotropic thermal distributed bi-Maxwellian and Cairns distributions of electrons to obtain the damping rates of twisted *** dispersion relation and Landau damping of Langmuir twisted modes are *** presence of twisted modes opens up two more possibilities in Landau damping and dispersion *** may generate a mixture with ion sound *** seems to play the role of a control parameter of Landau damping.

关键词： Landau damping Cairns distribution function anisotropic

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Future Pharmacotherapy for Non-alcoholic Steatohepatitis (NASH): review of Phase 2 and 3 Trials

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Journal of Clinical and Translational Hepatology 2018年第3期6卷 264-275页

作者： James J.Connolly kohtaro Ooka Joseph k.lim Department of Internal Medicine Yale University School of MedicineNew HavenCTUSA Division of Gastroenterology Hepatology and NutritionUniversity of Pittsburgh Medical CenterPittsburghPAUSA Yale Liver Center Section of Digestive DiseasesYale University School of MedicineNew HavenCTUSA

Non-alcoholic steatohepatitis(NASH)results from inflammation and hepatocyte injury in the setting of hepatic ***-alcoholic steatohepatitis increases the risk of progression to liver fibrosis and cirrhosis,and is the most rapidly growing etiology for liver failure and indication for liver transplantation in the *** loss and lifestyle modification remain the standard first-line treatment,as no USA Food and Drug Administration-approved pharmacotherapy currently *** past decade has seen an explosion of interest in drug development targeting pathologic pathways in non-alcoholic steatohepatitis,with numerous phase 2 and 3 trials currently in ***,we concisely review the major targets and mechanisms of action by class,summarize results from com-pleted pivotal phase 2 studies,and provide a detailed outline of key active studies with trial data for drugs in development,including obeticholic acid,elafibranor,cenicriviroc and selonsertib.

关键词： Fatty liver Non-alcoholic steatohepatitis Clinical trials Pharmacotherapy Obeticholic acid

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Growth and Characterization of Pencil-Like ZnO Nanowires in the Presence of a Disturbance in Boundary Layer

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Acta Metallurgica Sinica(English Letters) 2016年第6期29卷 595-600页

作者： A.kamalianfar Mahmoud Godarz Naseri Marzih kamalianfar S.A.Halim k.P.lim Department of Physics Faculty of Science Farhangian University Ministry of Education Fars Education Department of Physics Faculty of Science Malayer University Department of Physics Faculty of Science University Putra MalaysiaUPM

Pencil-like zinc oxide（ZnO） nanowire was synthesized on Si（111） substrate through a simple vapor phase method using a mixture of zinc oxide and graphite as the source material. The source inside a quartz tube created a Zn-rich vapor that facilitated the formation and growth of ZnO nanowires. Field emission scanning electron microscopic studies indicated that pencil-like ZnO nanowires had a size of the range from 50 to 150 nm in diameter and several microns in length. X-ray diffraction was used to investigate the crystal structure of ZnO nanowires. raman scattering and photoluminescence were applied to characterize the optical properties of the pencils. The growth mechanism of the nanopencils was discussed based on the growth conditions.

关键词： Zinc oxide Nanowires Vapor-phase transport Pencil-like

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Online AUV Path replanning Using Quantum-Behaved Particle Swarm Optimization with Selective Differential Evolution

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Computer Modeling in Engineering & Sciences 2020年第10期125卷 33-50页

作者： Hui Sheng lim Christopher k.H.Chin Shuhong Chai Neil Bose National Centre for Maritime Engineering and Hydrodynamics Australian Maritime CollegeUniversity of TasmaniaLauncestonTAS7250Australia Memorial University of Newfoundland St.John’sNLA1C 5S7Canada

This paper presents an online AUV(autonomous underwater vehicle)path planner that employs path replanning approach and the SDEQPSO(selective differential evolution-hybridized quantum-behaved particle swarm optimization)algorithm to optimize an AUV mission conducted in an unknown,dynamic and cluttered ocean *** proposed path replanner considered the effect of ocean currents in path optimization to generate a Pareto-optimal path that guides the AUV to its target within minimum *** optimization was based on the onboard sensor data measured from the environment,which consists of a priori unknown dynamic obstacles and spatiotemporal *** sensor arrangements for the forward-looking sonar and horizontal acoustic Doppler current profiler(H-ADCP)were considered in 2D and 3D *** on the simulation results,the SDEQPSO path replanner was found to be capable of generating a time-optimal path that offered up to 13%reduction in travel time compared to the situation where the vehicle simply followed a path with the shortest *** proposed replanning technique also showed consistently better performance over a reactive path planner in terms of solution quality,stability,and computational *** of the replanner was verified under stochastic process using the Monte Carlo *** generated path fulfilled the vehicle’s safety and physical constraints,while intelligently exploiting ocean currents to improve the vehicle’s efficiency.

关键词： Autonomous underwater vehicle path planning particle swarm optimization sonar detection Monte Carlo methods

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Emissions of Er3+ and Yb3+ co-doped SrZrO3 nanocrystals under near-infrared and near-ultraviolet excitations

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Journal of Advanced Ceramics 2020年第4期9卷 413-423页

作者： Hyeontae lim Juyeong lim Soyoung Jang Y.S.Lee Department of Physics Soongsil UniversitySeoul06978Republic of Korea

In this study,the upconversion(UC)emissions of Er3+and Yb3+co-doped SrZrO3 nanocrystals(NCs)were investigated in terms of the thermal annealing temperature and concentration of Er3+ions and compared with the emissions under a near-ultraviolet(near-UV)*** NCs were synthesized by the combustion method,and the as-synthesized NCs were post-annealed at high *** X-ray diffraction patterns revealed that the grain sizes and crystallinity degrees of the samples increased with increasing annealing *** photoluminescence spectra of our samples exhibited strong green and very weak red emissions with the near-UV excitation,originating from the f-f transitions in the Er3+***,under near-infrared(near-Ir)excitation,we identified sizable visible emissions at 525,547,and 660 nm in our NCs,which indicated that the UC process successfully occurred in our *** UC emissions were maximized in the NCs with an Er3+concentration of 0.02 and thermal annealing at 1000°*** found that the intensity ratios of red to green emissions increased with increasing annealing *** discussed the differences in the emissions between near-UV and near-Ir excitations.

关键词： Er3+and Yb3+co-doped SrZrO3 upconversion downshifting nanocrystals combustion method annealing temperature

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Effects of Diisopropylfluorophosphate on Brain Acetylcholinesterase, Butyryicholinesterase, and Neurotoxic Esterase in rats

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Biomedical and Environmental Sciences 1989年第3期2卷 295-304页

作者： D.k.lim B.HOSkINS I.k.HO Department of Pharmacology and Toxicology University of Mississippi Medical Center Jackson Mississippi 39216

The inhibition and the recovery of brain AChE, BuChE, and NTE activities after acute and subacute administration of DFP were studied in the rat. DFP displayed different specificities in inhibiting these enzymes; inhibition was greatest for BuChE followed by AChE and NTE. recovery was most rapid for BuChE followed by NTE and AChE. The recovery rates of AChE and BuChE following acute and subacute treatment were similar. However, the recovery rate of NTE in subacutely treated rats was significantly faster than that in acutely treated rats. The results suggest that DFP inhibits these three enzymes and the rates of regeneration of these enzymes are significantly different. (c)1989 Academic Press, Inc.

关键词： and Neurotoxic Esterase in rats Butyryicholinesterase Effects of Diisopropylfluorophosphate on Brain Acetylcholinesterase

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