237,217 research outputs found

    Super Dielectric Materials

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    Evidence is provided that a class of materials with dielectric constants greater than 100,000, herein called super dielectric materials (SDM), can be generated readily from common, inexpensive materials.Comment: The first material ever with an intrinsic dielectric constant greater than 100,000. Postulated to be a class of materials with super dielectric propertie

    Dependence of exciton transition energy of single-walled carbon nanotubes on surrounding dielectric materials

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    We theoretically investigate the dependence of exciton transition energies on dielectric constant of surrounding materials. We make a simple model for the relation between dielectric constant of environment and a static dielectric constant describing the effects of electrons in core states, σ\sigma bonds and surrounding materials. Although the model is very simple, calculated results well reproduce experimental transition energy dependence on dielectric constant of various surrounding materials.Comment: 5pages, 4 figure

    Thermal conductivity and dielectric constant of silicate materials

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    Report on the thermal conductivity and dielectric constant of nonmetallic materials evaluates the mechanisms of heat transfer in evacuated silicate powders and establishes the complex dielectric constant of these materials. Experimental measurements and results are related to postulated lunar surface materials

    Universal Electromagnetic Waves in Dielectric

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    The dielectric susceptibility of a wide class of dielectric materials follows, over extended frequency ranges, a fractional power-law frequency dependence that is called the "universal" response. The electromagnetic fields in such dielectric media are described by fractional differential equations with time derivatives of non-integer order. An exact solution of the fractional equations for a magnetic field is derived. The electromagnetic fields in the dielectric materials demonstrate fractional damping. The typical features of "universal" electromagnetic waves in dielectric are common to a wide class of materials, regardless of the type of physical structure, chemical composition, or of the nature of the polarizing species, whether dipoles, electrons or ions.Comment: 19 pages, LaTe

    Discharge characteristics of dielectric materials examined in mono-, dual-, and spectral energy electron charging environments

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    The effects of midenergy electrons on the charge and discharge characteristics of spacecraft dielectric materials and the data base from which basic discharge models can be formulated is expanded. Thin dielectric materials were exposed to low, mid combined low and mid, and spectral energy electron environments. Three important results are presented: (1) it determined electron environments that lead to dielectric discharges at potentials less negative than -5 kV; (2) two types of discharges were identified that dominate the kinds of discharges seen; and (3) it is shown that, for the thin dielectric materials tested, the worst-case discharges observed in the various environments are similar

    Repulsive Casimir forces between solid materials with high refractive index intervening liquids

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    In order to explore repulsive Casimir/van der Waals forces between solid materials with liquid as the intervening medium, we analyze dielectric data for a wide range of materials as for example PTFE, polystyrene, silica and more than twenty liquids. Although significant variation in the dielectric data from different sources exist, we provide a scheme based on measured static dielectric constants, refractive indices, and applying Kramers Kronig (KK) consistency to dielectric data to create accurate dielectric functions at imaginary frequencies. The latter is necessary for more accurate force calculations via the Lifshitz theory allowing reliable predictions of repulsive Casimir forces.Comment: 20 pages, 7 figures, 1 tabl

    Complex permittivity measurements at Ka-Band using rectangular dielectric waveguide

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    The rectangular dielectric waveguide (RDWG) technique has been developed for the determination of the dielectric constant of materials from effective refractive index measurements in the Q andWbands. This paper describes the use of an optimization method in conjunction with the RDWG technique for the determination of both the dielectric constant and loss tangent of materials at Ka-Band. The effect of the uncertainty in the measured sample thickness is presented
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