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David R. Smith

Bio: David R. Smith is an academic researcher from Duke University. The author has contributed to research in topics: Metamaterial & Antenna (radio). The author has an hindex of 110, co-authored 881 publications receiving 91683 citations. Previous affiliations of David R. Smith include Brunel University London & Princeton University.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the effects of disorder on metamaterial samples composed of split ring resonators with randomly introduced variation in their geometrical dimensions were investigated, and it was shown that disorder broadens the negative permeability band and introduces effective losses into the system.
Abstract: We investigate the effects of disorder on metamaterial samples composed of split ring resonators with randomly introduced variation in their geometrical dimensions. We demonstrate that disorder broadens the negative permeability band and introduces effective losses into the system. Transmission measurements on samples with varying degrees of disorder are found to be in excellent agreement with predictions based on standard homogenization theories.

53 citations

Book ChapterDOI
01 Jan 2010
TL;DR: In this article, the authors discuss the important issues for the development and future of metamaterials, including the optical transformation, effective medium theory for periodic structures, broadband and low-loss metammaterials, and potential applications.
Abstract: There have been increasing interests in metamaterials in the past 10 years in the scientific communities. However, metamaterials are sometimes regarded as left-handed materials or negative refractive index materials by a lot of people including researchers. In fact, the rapid development in this exciting area has shown that metamaterials are far beyond left-handed materials. In this chapter, we will clarify what metamaterial is and report the recent progress on metamaterials. We also summarize the important issues for the development and future of metamaterials, including the optical transformation, effective medium theory for periodic structures, broadband and low-loss metamaterials, rapid design of metamaterials, and potential applications. The impact of computational electromagnetics on metamaterials is briefly discussed.

52 citations

Journal ArticleDOI
J.E. Menard1, M. G. Bell1, R. E. Bell1, S. Bernabei1, J.M. Bialek2, T. M. Biewer1, W. R. Blanchard1, J.A. Boedo3, C.E. Bush4, Mark D. Carter4, Wonho Choe5, Neal Crocker6, D.S. Darrow1, W. Davis1, L. F. Delgado-Aparicio7, S. J. Diem1, Calvin Domier8, D. A. D'Ippolito, J.R. Ferron9, A. R. Field, J. Foley1, E.D. Fredrickson1, D.A. Gates1, T. Gibney1, R. W. Harvey, R. Hatcher1, William Heidbrink10, K. W. Hill1, J.C. Hosea1, Thomas Jarboe11, David W. Johnson1, R. Kaita1, Stanley Kaye1, Charles Kessel1, S. Kubota6, H.W. Kugel1, J. Lawson1, B. LeBlanc1, K. C. Lee8, Fred Levinton, Neville C. Luhmann8, Rajesh Maingi4, Richard Majeski1, J. Manickam1, D. K. Mansfield1, R.J. Maqueda, R. Marsala1, D. Mastrovito1, T. K. Mau3, E. Mazzucato1, S. S. Medley1, H. F. Meyer, D. R. Mikkelsen1, D. Mueller1, Tobin Munsat12, J.R. Myra, B. A. Nelson11, C. Neumeyer1, Nobuhiro Nishino13, M. Ono1, Hyeon K. Park1, W. Park1, S. F. Paul1, T. Peebles6, M. Peng4, C. K. Phillips1, A. Pigarov3, R.I. Pinsker9, Abhay K. Ram14, S. Ramakrishnan1, Roger Raman11, David A Rasmussen4, M. H. Redi1, M.E. Rensink15, G. Rewoldt1, J. Robinson1, P. Roney1, A. L. Roquemore1, E. Ruskov10, P.M. Ryan4, S.A. Sabbagh2, H. Schneider1, C.H. Skinner1, David R. Smith1, Aaron Sontag2, Vlad Soukhanovskii15, T. Stevenson1, D. P. Stotler1, Brentley Stratton1, Dan Stutman7, D.W. Swain4, E. J. Synakowski15, Yuichi Takase16, G. Taylor1, Kevin Tritz7, A. von Halle1, M. R. Wade9, Roscoe White1, John B Wilgen4, M. Williams1, J. R. Wilson1, Howard Yuh, Leonid E. Zakharov1, W. Zhu2, S. J. Zweben1, R. J. Akers, Peter Beiersdorfer15, Riccardo Betti17, T.S. Bigelow4, Manfred Bitter1, P.T. Bonoli14, Clarisse Bourdelle, Choong-Seock Chang18, J. Chrzanowski1, L. Dudek1, P. C. Efthimion1, Michael Finkenthal7, E. Fredd1, Guoyong Fu1, Alan H. Glasser19, Robert James Goldston20, N. L. Greenough1, L. R. Grisham1, N. N. Gorelenkov1, Luca Guazzotto17, R. J. Hawryluk1, J.T. Hogan4, Wayne A Houlberg4, D.A. Humphreys9, F. Jaeger4, M. Kalish1, Sergei Krasheninnikov3, L.L. Lao9, J. Lawrence1, J.A. Leuer9, D. W. Liu10, G. Oliaro1, D. Pacella, R. Parsells1, M.J. Schaffer9, I.B. Semenov21, Ker-Chung Shaing22, Michael A. Shapiro14, Kouji Shinohara23, P. Sichta1, Xian-Zhu Tang19, R. Vero7, M.L. Walker9, William R. Wampler24 
TL;DR: The National Spherical Torus Experiment (NSTX) has made considerable progress in advancing the scientific understanding of high performance long-pulse plasmas needed for future spherical torus (ST) devices and ITER.
Abstract: The National Spherical Torus Experiment (NSTX) has made considerable progress in advancing the scientific understanding of high performance long-pulse plasmas needed for future spherical torus (ST) devices and ITER. Plasma durations up to 1.6 s (five current redistribution times) have been achieved at plasma currents of 0.7 MA with non-inductive current fractions above 65% while simultaneously achieving βT and βN values of 17% and 5.7 (%m T MA−1), respectively. A newly available motional Stark effect diagnostic has enabled validation of current-drive sources and improved the understanding of NSTX 'hybrid'-like scenarios. In MHD research, ex-vessel radial field coils have been utilized to infer and correct intrinsic EFs, provide rotation control and actively stabilize the n = 1 resistive wall mode at ITER-relevant low plasma rotation values. In transport and turbulence research, the low aspect ratio and a wide range of achievable β in the NSTX provide unique data for confinement scaling studies, and a new microwave scattering diagnostic is being used to investigate turbulent density fluctuations with wavenumbers extending from ion to electron gyro-scales. In energetic particle research, cyclic neutron rate drops have been associated with the destabilization of multiple large toroidal Alfven eigenmodes (TAEs) analogous to the 'sea-of-TAE' modes predicted for ITER, and three-wave coupling processes have been observed for the first time. In boundary physics research, advanced shape control has enabled studies of the role of magnetic balance in H-mode access and edge localized mode stability. Peak divertor heat flux has been reduced by a factor of 5 using an H-mode-compatible radiative divertor, and lithium conditioning has demonstrated particle pumping and results in improved thermal confinement. Finally, non-solenoidal plasma start-up experiments have achieved plasma currents of 160 kA on closed magnetic flux surfaces utilizing coaxial helicity injection.

51 citations

Journal ArticleDOI
TL;DR: In this article, a planar array of split-ring resonators (SRRs) at varying angles of incidence is modeled as a thin continuous anisotropic crystal, and the model is then fit to experimental data to obtain the frequency-dependent permeability and permittivity of the SRR array.
Abstract: Artificially structured metamaterials with unit-cell dimensions on the order of $1∕10\text{th}$ of a wavelength $(\ensuremath{\lambda}∕10)$ have been shown to be well approximated by an effective medium description which mimics a continuous material. In this paper we present data for transmission and reflection from a planar array of split-ring resonators (SRRs) at varying angles of incidence. We attempt to model the form of the angle---dependent response of the SRRs using the Fresnel equations formulated from effective medium theory---treating the array as a thin continuous anisotropic crystal. This model is then fit to experimental data taken on a planar array of split rings to gauge the model accuracy, and to produce values for the frequency-dependent permeability and permittivity of the experimental SRR array. Simultaneous fitting of the transmission and reflection at multiple angles helps to avoid multiple solutions for the permittivity and permeability. This forward fitting approach using multiple angles is advantageous, as it enables a characterization of the optical constants without the need for phase information, and it avoids many of the branch problems inherent in the numerical inversion methods used so far on metamaterials. The work presented here shows the feasibility of this method. A refined procedure will be particularly advantageous for experimental characterization of higher frequency structures (i.e., THz and above), where phase information is difficult or impossible to obtain.

51 citations


Cited by
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Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

18,940 citations

Journal ArticleDOI
TL;DR: A review of gold nanoparticles can be found in this article, where the most stable metal nanoparticles, called gold colloids (AuNPs), have been used for catalysis and biology applications.
Abstract: Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

11,752 citations

Journal ArticleDOI
14 Aug 2003-Nature
TL;DR: By altering the structure of a metal's surface, the properties of surface plasmons—in particular their interaction with light—can be tailored, which could lead to miniaturized photonic circuits with length scales that are much smaller than those currently achieved.
Abstract: Surface plasmons are waves that propagate along the surface of a conductor. By altering the structure of a metal's surface, the properties of surface plasmons--in particular their interaction with light--can be tailored, which offers the potential for developing new types of photonic device. This could lead to miniaturized photonic circuits with length scales that are much smaller than those currently achieved. Surface plasmons are being explored for their potential in subwavelength optics, data storage, light generation, microscopy and bio-photonics.

10,689 citations

Journal ArticleDOI
01 Apr 1988-Nature
TL;DR: In this paper, a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) is presented.
Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

9,929 citations