The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform
Georgios Leonidopoulos - One of the best experts on this subject based on the ideXlab platform.
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Recovery behaviour of thin polyester film Surface Resistance under the influence of different liquids
Polymer Testing, 2003Co-Authors: Georgios LeonidopoulosAbstract:Abstract In this paper, the effect of different solvents on thin dielectric film Surface Resistance measurement is examined. The experiments reveal a decrease of the Surface Resistance value with the application of a solvent. After a period of time that is usually different for every individual solvent, the Surface Resistance value recovers back to its initial value, i.e. the value before the application of the solvent. But depending on its type, the solvent may cause a permanent change in the Resistance value with the result that the Surface Resistance recovers back to a value that is lower than its initial value.
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Does the Surface Resistance under measurement in the thin polymeric film Surface Resistance measurement method vary during the experimental response of the system
Polymer Testing, 1999Co-Authors: Georgios LeonidopoulosAbstract:Abstract In this paper it is examined whether the Surface Resistance under measurement, when the concentric cylindrical electrodes thin polymeric film Surface Resistance measurement method is utilized, varies during the experimental response of the system.
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Attempt to explain why the Surface Resistance under measurement in the thin polymeric film Surface Resistance measurement method varies during the experimental response of the system
Polymer Testing, 1999Co-Authors: Georgios LeonidopoulosAbstract:In this paper, an attempt is made to explain why the Surface Resistance under measurement, when the concentric cylindrical electrodes thin polymeric film Surface Resistance measurement method is used, varies during the experimental response of the system.
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Thin estrofol film Surface Resistance measurement using concentric cylindrical measuring system
Polymer Testing, 1991Co-Authors: Georgios LeonidopoulosAbstract:Abstract In this paper, a concentric cylindrical measuring system is utilised to study the Surface Resistance of estrofol films: a theoretical analysis is used to calculate the electric field in this system. Furthermore, the measuring system facilitates the investigation of the effects of different solvents on the estrofol film's Surface Resistance.
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Voltage distribution of two thin polymeric film Surface Resistance measurement systems
IEEE Transactions on Instrumentation and Measurement, 1991Co-Authors: Georgios LeonidopoulosAbstract:Two different methods for measuring the Surface Resistance of thin polymeric films are presented. The first method is the standard method and utilizes concentric ring metal electrodes. The second one is a novel method and uses instead concentric cylindrical metal electrodes. Both have been studied analytically and experimentally. The voltage distributions that are developed in both methods are calculated, plotted using three-dimensional graphs, and finally compared in order to analyze the advantages and disadvantages of the two measuring systems (acetate is the dielectric). The cylindrical electrodes, which give lower stresses around the outer electrode, seem to be more suitable for the measurements of the Surface Resistance of thin polymeric films.
Qishao Zhang - One of the best experts on this subject based on the ideXlab platform.
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A novel method for the measurement of frequency-character of Surface Resistance of HTS thin film
Chinese Science Bulletin, 2010Co-Authors: Cheng Zeng, Kai Yang, Shirong Bu, Qishao ZhangAbstract:A novel method for microwave Surface Resistance measurement of high temperature superconductor thin film at multi-frequency by multimode of sapphire rod is introduced. This method has the advantages of high sensitivity and large dynamic range of the measurement. By using this method, the frequency dependent microwave Surface Resistance of a single piece of high temperature superconductor thin film can be characterized within one temperature cycle. This method is capable of reducing the amount of work in Surface Resistance measurement and providing supports to the research and the industrialization of high temperature superconductor thin film.
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Accurate Measurement for Surface Resistance of a Single Piece of HTS Thin Film
2009 IEEE Circuits and Systems International Conference on Testing and Diagnosis, 2009Co-Authors: Cheng Zeng, Kai Yang, Qishao ZhangAbstract:An improved image type sapphire resonator was developed for accurate measurement of Surface Resistance of a single piece of high temperature superconductor thin film. The Surface Resistances of two DC spurting yttrium-barium-copper oxide (YBCO) thin films were measured by TE011 mode of this resonator. TE012 mode of this resonator was also used in the measurement for the determination of the frequency dependence of the Surface Resistance of the HTS thin film. The high accuracy in the Rs measurement of this resonator is comparable to the one of conventional two-resonator method, while the process is much simpler. The ability for measuring Surface Resistance of a single HTS thin film and characterizing the frequency dependence of Rs of this sapphire resonator is remarkable.
Tsuneo Konaka - One of the best experts on this subject based on the ideXlab platform.
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High-Frequency Surface Resistance of Sputtered EuBa2Cu3O7-x Thin Films
Advances in Superconductivity IV, 1992Co-Authors: Hidefumi Asano, Makoto Satoh, Tsuneo KonakaAbstract:We examine the high-frequency Surface Resistance of sputtered EuBa2Cu3O7-x films on MgO, YAlO3, and Sapphire substrates having favorable dielectric properties. Surface Resistance measurement is performed as a function of temperature by end-wall replacement in a 50 GHz gold-plated Invar host cavity. For films with good in-plane epitaxial alignment, low Surface Resistance values of less than 10 mΩ at 77 K are obtained, which is in the same range as that for a classical superconductor of Nb at the same reduced temperature (T/Tc) of 7.7 K. Microstructural study with a transmission electron micrography (TEM) indicates that a number of defects related with in-plane misorientation are observed for films having poor microwave properties.
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Directional dependence of magnetic field induced Surface Resistance in HTSC film
Physica C-superconductivity and Its Applications, 1991Co-Authors: Makoto Sato, Tsuneo Konaka, Hidefumi AsanoAbstract:Abstract Microwave Surface Resistance induced by a low magnetic field in HTSC thin film is measured using a coplanar line resonator. The directional dependence of field induced Surface Resistance is observed. To understand this directional dependence, it is useful to introduce the concept of intergrain flux-flow Resistance.
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Reduction of the Surface Resistance of YBa2Cu3O7-x pellets and thick films by adding Ag
Japanese Journal of Applied Physics, 1990Co-Authors: Osamu Ishii, Makoto Sato, Tsuneo Konaka, Yasuhiro KoshimotoAbstract:This letter describes the effect of Ag addition on the Surface Resistance of sintered YBa2Cu3O7-x superconductors at 17 and 50 GHz. The Surface Resistance decreases more than 50% by adding Ag into a pellet or a thick film of YBa2Cu3O7-x. The thick film exhibits a Surface Resistance of 22 mΩ at 17 GHz and at 77 K, which is almost equal to that of pure Cu. It is also revealed that the Surface Resistance is proportional to the square of the frequency. These phenomena are discussed in terms of the effect of Ag on the morphologies and c-axis orientation of YBa2Cu3O7-x grains.
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Millimeter-Wave Surface Resistance of EuBa2Cu3O7-y Film on MgO Substrates
Japanese Journal of Applied Physics, 1990Co-Authors: Tsuneo Konaka, Makoto Sato, Hidefumi AsanoAbstract:We have measured the Surface Resistance of c-axis-oriented EuBa2Cu3O7-y thin films grown in situ onto (100)MgO by magnetron sputtering. The measurements were made at 50 GHz between 20 and 300 K in a TE013 gold-plated invar cavity by replacing the endplate with a film. The Surface Resistance decreases sharply at 87 K to 40 m Ω at 77 K, becomes lower than that of an OFHC copper plate below 74 K, and lies within the measurement sensitivity range of 2 m Ω below 60 K. This low Surface Resistance suggests that MgO-based films are very suitable for high-frequency applications.
Hidefumi Asano - One of the best experts on this subject based on the ideXlab platform.
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High-Frequency Surface Resistance of Sputtered EuBa2Cu3O7-x Thin Films
Advances in Superconductivity IV, 1992Co-Authors: Hidefumi Asano, Makoto Satoh, Tsuneo KonakaAbstract:We examine the high-frequency Surface Resistance of sputtered EuBa2Cu3O7-x films on MgO, YAlO3, and Sapphire substrates having favorable dielectric properties. Surface Resistance measurement is performed as a function of temperature by end-wall replacement in a 50 GHz gold-plated Invar host cavity. For films with good in-plane epitaxial alignment, low Surface Resistance values of less than 10 mΩ at 77 K are obtained, which is in the same range as that for a classical superconductor of Nb at the same reduced temperature (T/Tc) of 7.7 K. Microstructural study with a transmission electron micrography (TEM) indicates that a number of defects related with in-plane misorientation are observed for films having poor microwave properties.
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Directional dependence of magnetic field induced Surface Resistance in HTSC film
Physica C-superconductivity and Its Applications, 1991Co-Authors: Makoto Sato, Tsuneo Konaka, Hidefumi AsanoAbstract:Abstract Microwave Surface Resistance induced by a low magnetic field in HTSC thin film is measured using a coplanar line resonator. The directional dependence of field induced Surface Resistance is observed. To understand this directional dependence, it is useful to introduce the concept of intergrain flux-flow Resistance.
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Millimeter-Wave Surface Resistance of EuBa2Cu3O7-y Film on MgO Substrates
Japanese Journal of Applied Physics, 1990Co-Authors: Tsuneo Konaka, Makoto Sato, Hidefumi AsanoAbstract:We have measured the Surface Resistance of c-axis-oriented EuBa2Cu3O7-y thin films grown in situ onto (100)MgO by magnetron sputtering. The measurements were made at 50 GHz between 20 and 300 K in a TE013 gold-plated invar cavity by replacing the endplate with a film. The Surface Resistance decreases sharply at 87 K to 40 m Ω at 77 K, becomes lower than that of an OFHC copper plate below 74 K, and lies within the measurement sensitivity range of 2 m Ω below 60 K. This low Surface Resistance suggests that MgO-based films are very suitable for high-frequency applications.
Howard A. Blackstead - One of the best experts on this subject based on the ideXlab platform.
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Current-activated residual Surface Resistance in high temperature superconductors
Solid State Communications, 1991Co-Authors: Howard A. BlacksteadAbstract:Abstract A prominent and unusual feature of the microwave Surface Resistance of high temperature superconductors is a comparatively large “residual” Resistance observed from a few degrees below the transition temperature, to the lowest temperatures. This Resistance, which varies slowly with temperature, is also observed to vary with the rf field amplitude, sample quality, and frequency. Using a classical treatment for the rf field, we show that a Surface Resistance ∼ mohms arises from current-activated phase-slip resistivity. At low temperatures, this contribution to the Surface Resistance varies approximately as ωH rf /J c0 , where ω is the angular frequency, H rf is the rf field amplitude, and J c0 is the inter-granular critical current.
