3,866 research outputs found

    Realization of an all-dielectric zero-index optical metamaterial

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    Metamaterials offer unprecedented flexibility for manipulating the optical properties of matter, including the ability to access negative index, ultra-high index and chiral optical properties. Recently, metamaterials with near-zero refractive index have drawn much attention. Light inside such materials experiences no spatial phase change and extremely large phase velocity, properties that can be applied for realizing directional emission, tunneling waveguides, large area single mode devices, and electromagnetic cloaks. However, at optical frequencies previously demonstrated zero- or negative-refractive index metamaterials require the use of metallic inclusions, leading to large ohmic loss, a serious impediment to device applications. Here, we experimentally demonstrate an impedance matched zero-index metamaterial at optical frequencies based on purely dielectric constituents. Formed from stacked silicon rod unit cells, the metamaterial possesses a nearly isotropic low-index response leading to angular selectivity of transmission and directive emission from quantum dots placed within the material.Comment: 15 pages, 5 figure

    Analisis Peran Ganda dan Strategi Pemberdayaan Janda yang Bekerja (Studi Empiris Derah Pesisir di Kota Semarang)

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    This study examines the role of widows in the coastal area of Semarang city. Widows were low in education level and limited economic access are found in the study area. They obtained survive to fight for their household economy limitation. The objectives of the study are to determine the role of the widows with low income level who are responsible to finance their households. Besides that, this study have objective to formulate the strategies of their empowerment. This study employed mixed method of combination between qualitative and quantitative approach to analyze the data. Snowballing sampling had has been involved to select the informants while purposive sampling was applied to select 100 respondents (widows) in the study area. The descriptive statistics and triangulation were used as the tools of analysis for this study. The results found that the level of powerment in economic, political, and social access were far from complete. The study outline the strategy to empower those widows through improving the productivity of respondents, extention the education access, provide trining to improve their skills and family advocation management

    Deployable antenna phase A study

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    Applications for large deployable antennas were re-examined, flight demonstration objectives were defined, the flight article (antenna) was preliminarily designed, and the flight program and ground development program, including the support equipment, were defined for a proposed space transportation system flight experiment to demonstrate a large (50 to 200 meter) deployable antenna system. Tasks described include: (1) performance requirements analysis; (2) system design and definition; (3) orbital operations analysis; and (4) programmatic analysis

    Convex politopes and quantum separability

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    We advance a novel perspective of the entanglement issue that appeals to the Schlienz-Mahler measure [Phys. Rev. A 52, 4396 (1995)]. Related to it, we propose an criterium based on the consideration of convex subsets of quantum states. This criterium generalizes a property of product states to convex subsets (of the set of quantum-states) that is able to uncover a new geometrical property of the separability property

    Decision Support System On Operating System

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    The micro-computing world of the ´ 90s is more volatile ever, not only having choices on which hardware to buy (and the brands to choose from seem to be endless). Nowadays, many stuff based on computer technology. Computer needs an operating system to handle the task. Open source gave paradigm in operating system developing. Now, we have to decide which operating system ( OS ) we are going to run on our computers. MS Windows is a leader operating system in desktop, Linux will be a leader operating system in server of internet. Currently, Linux give high effort to bring the operating system to desktop and entertainment. Many platform of hardware also were produced to fulfill the need of IT activities. A lot of applications have highly increased since twenty years ago. Many application can run in more operating system and hardware platform. The user need to consider which operating system appropriate to his system and purpose. In this paper, we will demonstrate matrix decision approach for decision support system (DSS) in choosing operating system. Section one will look at the relations between applications and hardware platform which related to operating system. Methodology of decision based on matrix decision will discuss in section two. Section three will look at some example scenarios in choosing operating system

    Facile O-atom insertion into C-C and C-H bonds by a trinuclear copper complex designed to harness a singlet oxene

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    Two trinuclear copper [CuICuICuI(L)]1+ complexes have been prepared with the multidentate ligands (L) 3,3'-(1,4-diazepane-1,4-diyl)bis(1-((2-(dimethylamino)ethyl)(methyl)amino)propan-2-ol) (7-Me) and (3,3'-(1,4-diazepane-1,4-diyl)bis(1-((2-(diethylamino) ethyl)(ethyl) amino)propan-2-ol) (7-Et) as models for the active site of the particulate methane monooxygenase (pMMO). The ligands were designed to form the proper spatial and electronic geometry to harness a "singlet oxene," according to the mechanism previously suggested by our laboratory. Consistent with the design strategy, both [CuICuICuI(L)]1+ reacted with dioxygen to form a putative bis(µ3-oxo)CuIICuIICuIII species, capable of facile O-atom insertion across the central C-C bond of benzil and 2,3-butanedione at ambient temperature and pressure. These complexes also catalyze facile O-atom transfer to the C-H bond of CH3CN to form glycolonitrile. These results, together with our recent biochemical studies on pMMO, provide support for our hypothesis that the hydroxylation site of pMMO contains a trinuclear copper cluster that mediates C-H bond activation by a singlet oxene mechanism

    Transformation Optics for Plasmonics

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    A new strategy to control the flow of surface plasmon polaritons at metallic surfaces is presented. It is based on the application of the concept of Transformation Optics to devise the optical parameters of the dielectric medium placed on top of the metal surface. We describe the general methodology for the design of Transformation-Optical devices for surface plasmons and analyze, for proof-of-principle purposes, three representative examples with different functionalities: a beam shifter, a cylindrical cloak and a ground-plane cloak.Comment: 15 pages, 3 figure

    The Spatial String Tension, Thermal Phase Transition, and AdS/QCD

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    We present results of modeling the temperature dependence of the spatial string tension and thermal phase transition in a five-dimensional framework nowadays known as AdS/QCD. For temperatures close to the critical one we find a behaviour remarkably consistent with the lattice results.Comment: 8 pages, 4 figure

    Molecular and morphometric variation in European populations of the articulate brachiopod <i>Terebeatulina retusa</i>

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    Molecular and morphometric variation within and between population samples of the articulate brachiopod &lt;i&gt;Terebratulina&lt;/i&gt; spp., collected in 1985-1987 from a Norwegian fjord, sea lochs and costal sites in western Scotland, the southern English Channel (Brittany) and the western Mediterranean, were measured by the analysis of variation in the lengths of mitochondrial DNA (mtDNA) fragments produced by digestion with nine restriction endonucleases and by multivariate statistical analysis of six selected morphometric parameters. Nucleotide difference within each population sample was high. Nucleotide difference between population samples from the Scottish sites, both those that are tidally contiguous and those that appear to be geographically isolated, were not significantly different from zero. Nucleotide differences between the populations samples from Norway, Brittany, Scotland and the western Mediterranean were also very low. Morphometric analysis confirmed the absence of substantial differentiation

    A special simplex in the state space for entangled qudits

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    Focus is on two parties with Hilbert spaces of dimension d, i.e. "qudits". In the state space of these two possibly entangled qudits an analogue to the well known tetrahedron with the four qubit Bell states at the vertices is presented. The simplex analogue to this magic tetrahedron includes mixed states. Each of these states appears to each of the two parties as the maximally mixed state. Some studies on these states are performed, and special elements of this set are identified. A large number of them is included in the chosen simplex which fits exactly into conditions needed for teleportation and other applications. Its rich symmetry - related to that of a classical phase space - helps to study entanglement, to construct witnesses and perform partial transpositions. This simplex has been explored in details for d=3. In this paper the mathematical background and extensions to arbitrary dimensions are analysed.Comment: 24 pages, in connection with the Workshop 'Theory and Technology in Quantum Information, Communication, Computation and Cryptography' June 2006, Trieste; summary and outlook added, minor changes in notatio
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