The Experts below are selected from a list of 54 Experts worldwide ranked by ideXlab platform
Jurgen Rodel - One of the best experts on this subject based on the ideXlab platform.
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lead free high temperature dielectrics with wide operational range
Journal of Applied Physics, 2011Co-Authors: Robert Dittmer, Dragan Damjanovic, Jurgen RodelAbstract:The dielectric, electrical and structural properties of (1–x)(0.94Bi1/2Na1/2TiO3–0.06BaTiO3)–xK0.5Na0.5NbO3 (BNT–BT–xKNN) with x=0.09, 0.12, 0.15, and 0.18 were investigated as potential candidates for high-temperature capacitors with a working temperature far beyond 200 °C. Temperature dependent dielectric Permittivity (e) showed two local broad maxima that at the optimal composition of KNN (x=0.18) are combined to form a plateau. This then results in a highly temperature-insensitive Permittivity up to ∼300 °C at the expense of a small reduction in Absolute Permittivity values. High-temperature in situ x-ray diffraction study showed pseudocubic symmetry without obvious structural changes, which implies that the dielectric anomalies observed could only be a consequence of a slight change in space group. BNT–BT–0.18KNN showed a Permittivity of ∼2150 at the frequency of 1 kHz at 150 °C with a normalized Permittivity e/e150 °C varying no more than ±10% from 43 to 319 °C. With very good electrical properties ...
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Lead-free high-temperature dielectrics with wide operational range
Journal of Applied Physics, 2011Co-Authors: Robert Dittmer, Dragan Damjanovic, Jurgen RodelAbstract:The dielectric, electrical and structural properties of (1-x) (0.94Bi(1/2)Na(1/2)TiO(3)-0.06BaTiO(3))-xK(0.5)Na(0.5)NbO(3) (BNT-BT-xKNN) with x=0.09, 0.12, 0.15, and 0.18 were investigated as potential candidates for high-temperature capacitors with a working temperature far beyond 200 degrees C. Temperature dependent dielectric Permittivity (epsilon) showed two local broad maxima that at the optimal composition of KNN (x=0.18) are combined to form a plateau. This then results in a highly temperature-insensitive Permittivity up to similar to 300 degrees C at the expense of a small reduction in Absolute Permittivity values. High-temperature in situ x-ray diffraction study showed pseudocubic symmetry without obvious structural changes, which implies that the dielectric anomalies observed could only be a consequence of a slight change in space group. BNT-BT-0.18KNN showed a Permittivity of similar to 2150 at the frequency of 1 kHz at 150 degrees C with a normalized Permittivity epsilon/epsilon(150 degrees C) varying no more than +/- 10% from 43 to 319 degrees C. With very good electrical properties persisting up to 300 degrees C, i.e., a resistivity on the order of magnitude of 10(8) Omega m and the RC constant of about 1 s, the examined BNT-BT-xKNN compositions present a good starting point for the development of high-temperature capacitor materials.open343
Robert Dittmer - One of the best experts on this subject based on the ideXlab platform.
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lead free high temperature dielectrics with wide operational range
Journal of Applied Physics, 2011Co-Authors: Robert Dittmer, Dragan Damjanovic, Jurgen RodelAbstract:The dielectric, electrical and structural properties of (1–x)(0.94Bi1/2Na1/2TiO3–0.06BaTiO3)–xK0.5Na0.5NbO3 (BNT–BT–xKNN) with x=0.09, 0.12, 0.15, and 0.18 were investigated as potential candidates for high-temperature capacitors with a working temperature far beyond 200 °C. Temperature dependent dielectric Permittivity (e) showed two local broad maxima that at the optimal composition of KNN (x=0.18) are combined to form a plateau. This then results in a highly temperature-insensitive Permittivity up to ∼300 °C at the expense of a small reduction in Absolute Permittivity values. High-temperature in situ x-ray diffraction study showed pseudocubic symmetry without obvious structural changes, which implies that the dielectric anomalies observed could only be a consequence of a slight change in space group. BNT–BT–0.18KNN showed a Permittivity of ∼2150 at the frequency of 1 kHz at 150 °C with a normalized Permittivity e/e150 °C varying no more than ±10% from 43 to 319 °C. With very good electrical properties ...
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Lead-free high-temperature dielectrics with wide operational range
Journal of Applied Physics, 2011Co-Authors: Robert Dittmer, Dragan Damjanovic, Jurgen RodelAbstract:The dielectric, electrical and structural properties of (1-x) (0.94Bi(1/2)Na(1/2)TiO(3)-0.06BaTiO(3))-xK(0.5)Na(0.5)NbO(3) (BNT-BT-xKNN) with x=0.09, 0.12, 0.15, and 0.18 were investigated as potential candidates for high-temperature capacitors with a working temperature far beyond 200 degrees C. Temperature dependent dielectric Permittivity (epsilon) showed two local broad maxima that at the optimal composition of KNN (x=0.18) are combined to form a plateau. This then results in a highly temperature-insensitive Permittivity up to similar to 300 degrees C at the expense of a small reduction in Absolute Permittivity values. High-temperature in situ x-ray diffraction study showed pseudocubic symmetry without obvious structural changes, which implies that the dielectric anomalies observed could only be a consequence of a slight change in space group. BNT-BT-0.18KNN showed a Permittivity of similar to 2150 at the frequency of 1 kHz at 150 degrees C with a normalized Permittivity epsilon/epsilon(150 degrees C) varying no more than +/- 10% from 43 to 319 degrees C. With very good electrical properties persisting up to 300 degrees C, i.e., a resistivity on the order of magnitude of 10(8) Omega m and the RC constant of about 1 s, the examined BNT-BT-xKNN compositions present a good starting point for the development of high-temperature capacitor materials.open343
Dragan Damjanovic - One of the best experts on this subject based on the ideXlab platform.
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lead free high temperature dielectrics with wide operational range
Journal of Applied Physics, 2011Co-Authors: Robert Dittmer, Dragan Damjanovic, Jurgen RodelAbstract:The dielectric, electrical and structural properties of (1–x)(0.94Bi1/2Na1/2TiO3–0.06BaTiO3)–xK0.5Na0.5NbO3 (BNT–BT–xKNN) with x=0.09, 0.12, 0.15, and 0.18 were investigated as potential candidates for high-temperature capacitors with a working temperature far beyond 200 °C. Temperature dependent dielectric Permittivity (e) showed two local broad maxima that at the optimal composition of KNN (x=0.18) are combined to form a plateau. This then results in a highly temperature-insensitive Permittivity up to ∼300 °C at the expense of a small reduction in Absolute Permittivity values. High-temperature in situ x-ray diffraction study showed pseudocubic symmetry without obvious structural changes, which implies that the dielectric anomalies observed could only be a consequence of a slight change in space group. BNT–BT–0.18KNN showed a Permittivity of ∼2150 at the frequency of 1 kHz at 150 °C with a normalized Permittivity e/e150 °C varying no more than ±10% from 43 to 319 °C. With very good electrical properties ...
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Lead-free high-temperature dielectrics with wide operational range
Journal of Applied Physics, 2011Co-Authors: Robert Dittmer, Dragan Damjanovic, Jurgen RodelAbstract:The dielectric, electrical and structural properties of (1-x) (0.94Bi(1/2)Na(1/2)TiO(3)-0.06BaTiO(3))-xK(0.5)Na(0.5)NbO(3) (BNT-BT-xKNN) with x=0.09, 0.12, 0.15, and 0.18 were investigated as potential candidates for high-temperature capacitors with a working temperature far beyond 200 degrees C. Temperature dependent dielectric Permittivity (epsilon) showed two local broad maxima that at the optimal composition of KNN (x=0.18) are combined to form a plateau. This then results in a highly temperature-insensitive Permittivity up to similar to 300 degrees C at the expense of a small reduction in Absolute Permittivity values. High-temperature in situ x-ray diffraction study showed pseudocubic symmetry without obvious structural changes, which implies that the dielectric anomalies observed could only be a consequence of a slight change in space group. BNT-BT-0.18KNN showed a Permittivity of similar to 2150 at the frequency of 1 kHz at 150 degrees C with a normalized Permittivity epsilon/epsilon(150 degrees C) varying no more than +/- 10% from 43 to 319 degrees C. With very good electrical properties persisting up to 300 degrees C, i.e., a resistivity on the order of magnitude of 10(8) Omega m and the RC constant of about 1 s, the examined BNT-BT-xKNN compositions present a good starting point for the development of high-temperature capacitor materials.open343
Vasily E. Tarasov - One of the best experts on this subject based on the ideXlab platform.
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Electric field in media with power-law spatial dispersion
Modern Physics Letters B, 2016Co-Authors: Vasily E. TarasovAbstract:In this paper, we consider electric fields in media with power-law spatial dispersion (PLSD). Spatial dispersion means that the Absolute Permittivity of the media depends on the wave vector. Power-law type of this dispersion is described by derivatives and integrals of non-integer orders. We consider electric fields of point charge and dipole in media with PLSD, infinite charged wire, uniformly charged disk, capacitance of spherical capacitor and multipole expansion for PLSD-media.
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Power-law spatial dispersion from fractional Liouville equation
Physics of Plasmas, 2013Co-Authors: Vasily E. TarasovAbstract:A microscopic model in the framework of fractional kinetics to describe spatial dispersion of power-law type is suggested. The Liouville equation with the Caputo fractional derivatives is used to obtain the power-law dependence of the Absolute Permittivity on the wave vector. The fractional differential equations for electrostatic potential in the media with power-law spatial dispersion are derived. The particular solutions of these equations for the electric potential of point charge in this media are considered.
Hamid Dehghani - One of the best experts on this subject based on the ideXlab platform.
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Helmholtz-type regularization method for Permittivity reconstruction using experimental phantom data of electrical capacitance tomography
2016Co-Authors: Manuchehr Soleimani, Phaneendra K. Yalavarthy, Hamid DehghaniAbstract:Abstract—Electrical capacitance tomography (ECT) attempts to image the Permittivity distribution of an object by measuring the electrical capacitance between sets of electrodes placed around its periphery. Image reconstruction in ECT is a nonlinear ill-posed inverse problem, and regularization methods are needed to stabi-lize this inverse problem. The reconstruction of complex shapes (sharp edges) and Absolute Permittivity values is a more difficult task in ECT, and the commonly used regularization methods in Tikhonov minimization are unable to solve these problems. In the standard Tikhonov regularization method, the regularization ma-trix has a Laplacian-type structure, which encourages smoothing reconstruction. A Helmholtz-type regularization scheme has been implemented to solve the inverse problem with complicated-shape objects and the Absolute Permittivity values. The Helmholtz-type regularization has a wavelike property and encourages variations of Permittivity. The results from experimental data demonstrate the advantage of the Helmholtz-type regularization for recovering sharp edges over the popular Laplacian-type regularization in the framework of Tikhonov minimization. Furthermore, this paper presents examples of the reconstructed Absolute value Permittivity map in ECT using experimental phantom data. Index Terms—Electrical capacitance tomography (ECT), forward and inverse problems, Helmholtz-type regularization, Laplacian-type regularization, Permittivity imaging. I
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Helmholtz-Type Regularization Method for Permittivity Reconstruction Using Experimental Phantom Data of Electrical Capacitance Tomography
IEEE Transactions on Instrumentation and Measurement, 2010Co-Authors: Manuchehr Soleimani, Phaneendra K. Yalavarthy, Hamid DehghaniAbstract:Electrical capacitance tomography (ECT) attempts to image the Permittivity distribution of an object by measuring the electrical capacitance between sets of electrodes placed around its periphery. Image reconstruction in ECT is a nonlinear ill-posed inverse problem, and regularization methods are needed to stabilize this inverse problem. The reconstruction of complex shapes (sharp edges) and Absolute Permittivity values is a more difficult task in ECT, and the commonly used regularization methods in Tikhonov minimization are unable to solve these problems. In the standard Tikhonov regularization method, the regularization matrix has a Laplacian-type structure, which encourages smoothing reconstruction. A Helmholtz-type regularization scheme has been implemented to solve the inverse problem with complicated-shape objects and the Absolute Permittivity values. The Helmholtz-type regularization has a wavelike property and encourages variations of Permittivity. The results from experimental data demonstrate the advantage of the Helmholtz-type regularization for recovering sharp edges over the popular Laplacian-type regularization in the framework of Tikhonov minimization. Furthermore, this paper presents examples of the reconstructed Absolute value Permittivity map in ECT using experimental phantom data.
