نتایج جستجو برای: permittivity

تعداد نتایج: 5151  

2012
Andrzej Wilczek Agnieszka Szyplowska Wojciech Skierucha Jolanta Ciesla Viliam Pichler Grzegorz Janik

This paper presents the application of a frequency-domain reflectometry (FDR) sensor designed for soil salinity assessment of sandy mineral soils in a wide range of soil moisture and bulk electrical conductivity, through the determination of soil complex dielectric permittivity spectra in the frequency range 10-500 MHz. The real part of dielectric permittivity was assessed from the 380-440 MHz,...

2014
Ubaid ULLAH Mohd Fadzil AIN Mohamadariff OTHMAN Ihsan ZUBIR Nor Muzlifah MAHYUDDIN Zainal Ariffin AHMAD Mohd Zaid ABDULLAH

In this paper, a novel multi-permittivity cylindrical dielectric resonator antenna for wideband application is presented. The multi-permittivity cylinder is formed by combining two different permittivity material sectors in such a way that each sector (with constant permittivity) is 90 degree apart. A direct microstrip line coupling terminated with T-stub at the open end is used to excite the m...

Journal: :The journal of physical chemistry. B 2013
Bjørn Maribo-Mogensen Georgios M Kontogeorgis Kaj Thomsen

The static permittivity is a key property for describing solutions containing polar and hydrogen bonding compounds. However, the precise relationship between the molecular and dielectric properties is not well-established. Here we show that the relative permittivity at zero frequency (static permittivity) can be modeled simultaneously with thermodynamic properties. The static permittivity is ca...

1995
D. G. Myakishev V. P. Yakovlev

The equation (1) is solved by the finite element method. We use four corner eight nodes isoparametric elements. Algebraic system of equations for node field values is produced by Galerkin method. To find several modes simultaneously in arbitrary spectrum domain, we use subspace iteration method with frequency shift. If the permittivity and permeability of lossy filling depend on frequency, the ...

2011
P. Sabouroux

The principal aim of this article is the presentation of EpsiMu, a tool for dielectric properties measurement. This general tool can be used to characterize all types of materials, but in this article we apply it to porous or granular materials. The tool consists of a coaxial cell and dedicated software that allow us to reconstruct the permittivity in almost real-time by a de-embedding process....

2004
C Ortiz - Aleman R Martin J C Gamio

In this paper we introduce an image reconstruction technique for imaging permittivity distributions using electrical capacitance tomography, based on global optimization by very fast simulated annealing. Electrical capacitance measurement data are obtained between electrodes placed around the outer wall of an electrically insulating pipe. Such data are used to infer material distributions insid...

2003
V. Ballenegger J. - P. Hansen

– A statistical mechanics expression is derived for the space-dependent dielectric permittivity of a polar solvent near an interface. The asymptotic behaviour of this local per-mittivity is calculated in the low density limit, near a planar interface. The potential of mean force between two ions is shown to agree with the prediction of macroscopic electrostatics for large separations parallel t...

2010
Thomas Zentgraf Jason Valentine Nicholas Tapia Xiang Zhang

Device design using quasi-conformal mapping Figure 1 in the main text specifies how the boundaries between the virtual and the physical spaces of our device are transformed into each other. In principle, any coordinate map satisfying such a transformation can be used to construct the actual permittivity profile. However, this would lead in general to a very anisotropic permittivity for the stru...

Journal: :Advanced materials 2014
Yanwen Wu Chengdong Zhang N Mohammadi Estakhri Yang Zhao Jisun Kim Matt Zhang Xing-Xiang Liu Greg K Pribil Andrea Alù Chih-Kang Shih Xiaoqin Li

Using atomically smooth epitaxial silver films, new optical permittivity highlighting significant loss reduction in the visible frequency range is extracted. Largely enhanced propagation distances of surface plasmon polaritons are measured, confirming the low intrinsic loss in silver. The new permittivity is free of extrinsic spectral features associated with grain boundaries and localized plas...

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