WorldWideScience

Sample records for quasi-two-dimensional molecular conductor

  1. Quantum oscillations in quasi-two-dimensional conductors

    CERN Document Server

    Galbova, O

    2002-01-01

    The electronic absorption of sound waves in quasi-two-dimensional conductors in strong magnetic fields, is investigated theoretically. A longitudinal acoustic wave, propagating along the normal n-> to the layer of quasi-two-dimensional conductor (k-> = left brace 0,0,k right brace; u-> = left brace 0,0,u right brace) in magnetic field (B-> = left brace 0, 0, B right brace), is considered. The quasiclassical approach for this geometry is of no interest, due to the absence of interaction between electromagnetic and acoustic waves. The problem is of interest in strong magnetic field when quantization of the charge carriers energy levels takes place. The quantum oscillations in the sound absorption coefficient, as a function of the magnetic field, are theoretically observed. The experimental study of the quantum oscillations in quasi-two-dimensional conductors makes it possible to solve the inverse problem of determining from experimental data the extrema closed sections of the Fermi surface by a plane p sub z = ...

  2. Electron and electron-phonon effects in quasi-two-dimensional molecular conductor theta-(BETS) sub 4 HgBr sub 4 (C sub 6 H sub 5 Cl): optical investigations at 300-15 K

    CERN Document Server

    Vlasova, R M; Petrov, B V; Semkin, N D; Zhilyaeva, E I; Bogdanova, O A; Lyubovskaya, R N; Graja, A

    2002-01-01

    One studied the polarized spectra of reflection and spectra of optical transmission of theta-(BETS) sub 4 HgBr sub 4 (C sub 6 H sub 5 Cl) quasi-two-dimensional molecular conductor within 700-6500 cm sup - sup 1 range under 300-15 K temperatures and within 9000-40000 cm sup - sup 1 under 300 K for two principal directions within crystal plane parallel to conducting layers of BETS molecules. Under 300 K within IR region the spectra are characterized by the intensive essential peculiarities (1200-1400 cm sup - sup 1) caused by electron-oscillation coupling (EOC). At temperature drop within 180-80 K range one observes in the spectra a Lorentz term with omega sub t = 2900 cm sup - sup 1 and three extra bands within 800-1180 cm sup - sup 1 region caused by EOC. The derived results are indicative of unstable structural distortions along two principal directions in a crystal followed by formation of a charge density comparable wave

  3. Mechanism of Superconductivity in Quasi-Two-Dimensional Organic Conductor β-(BDA-TTP) Salts

    Science.gov (United States)

    Nonoyama, Yoshito; Maekawa, Yukiko; Kobayashi, Akito; Suzumura, Yoshikazu; Ito, Hiroshi

    2008-09-01

    We investigate theoretically the superconductivity of two-dimensional organic conductors, β-(BDA-TTP)2SbF6 and β-(BDA-TTP)2AsF6, to understand the role of the spin and charge fluctuations. The transition temperature is estimated by applying random phase approximation to an extended Hubbard model wherein realistic transfer energies are estimated by extended Hückel calculation. We find a gapless superconducting state with a dxy-like symmetry, which is consistent with the experimental results obtained by specific heat and scanning tunneling microscope. In the present model with an effectively half-filled triangular lattice, spin fluctuation competes with charge fluctuation as a mechanism of pairing interaction since both fluctuations have the same characteristic momentum q=(π,0) for V being smaller than U. This is in contrast to a model with a quarter-filled square lattice, wherein both fluctuations contribute cooperatively to pairing interaction due to fluctuations having different characteristic momenta. The resultant difference in the superconductivity of these two materials is also discussed.

  4. Magnetic ground state of quasi-two-dimensional organic conductor, τ-(EDO-S,S-DMEDT-TTF)2(AuCl2)1+y

    International Nuclear Information System (INIS)

    Nakanishi, T; Yasuzuka, S; Yoshino, H; Fujiwara, H; Sugimoto, T; Nishio, Y; Kajita, K; Anyfantis, G A; Papavassiliou, G C; Murata, K

    2006-01-01

    To understand the interplay between transport and magnetic properties, quasi-two-dimensional (Q2D) organic conductor τ-(EDO-S,S-DMEDTTTF) 2 (AuCl 2 ) 1+y was studied by measurements of electric resistivity ( ρ a , ρ c ), magnetoresistance (MR), susceptibility (χ) and specific heat (C) in the temperature region between 1 K and 300 K. In spite of the fact that the drastic changes were observed in ρ a , ρ c , MR and χ at T C = 20 K, no anomaly was seen in C. The concentration of spins estimated from M-H curve is about 360 ppm, which is difficult to detect anomaly in C. These data suggest that the number of spins is very small in the ground state like spin-glass system

  5. High magnetic field studies of the charge density wave state of the quasi-two-dimensional conductor KMO 6O 17

    Science.gov (United States)

    Dumas, Jean; Guyot, Hervé; Balaska, Hafid; Marcus, Jacques; Vignolles, David; Sheikin, Ilya; Audouard, Alain; Brossard, Luc; Schlenker, Claire

    2004-04-01

    Magnetic torque and magnetoresistance measurements have been performed in high magnetic field on the quasi-two-dimensional charge density wave (CDW) oxide bronze KMo 6O 17 . Several anomalies have been found below 28 T either on the torque or on the magnetoresistance data. They can be attributed predominantly to orbital effects. Magnetoresistance data obtained up to 55 T show that a transition takes place above 30 T. This transition may be due to the Pauli coupling. The new field-induced density wave state exhibits Shubnikov-de Haas (SdH) oscillations.

  6. High magnetic field studies of the charge density wave state of the quasi-two-dimensional conductor KMO{sub 6}O{sub 17}

    Energy Technology Data Exchange (ETDEWEB)

    Dumas, Jean; Guyot, Herve; Balaska, Hafid; Marcus, Jacques; Vignolles, David; Sheikin, Ilya; Audouard, Alain; Brossard, Luc; Schlenker, Claire

    2004-04-30

    Magnetic torque and magnetoresistance measurements have been performed in high magnetic field on the quasi-two-dimensional charge density wave (CDW) oxide bronze KMo{sub 6}O{sub 17} . Several anomalies have been found below 28 T either on the torque or on the magnetoresistance data. They can be attributed predominantly to orbital effects. Magnetoresistance data obtained up to 55 T show that a transition takes place above 30 T. This transition may be due to the Pauli coupling. The new field-induced density wave state exhibits Shubnikov-de Haas (SdH) oscillations.

  7. High magnetic field studies of the charge density wave state of the quasi-two-dimensional conductor KMO6O17

    International Nuclear Information System (INIS)

    Dumas, Jean; Guyot, Herve; Balaska, Hafid; Marcus, Jacques; Vignolles, David; Sheikin, Ilya; Audouard, Alain; Brossard, Luc; Schlenker, Claire

    2004-01-01

    Magnetic torque and magnetoresistance measurements have been performed in high magnetic field on the quasi-two-dimensional charge density wave (CDW) oxide bronze KMo 6 O 17 . Several anomalies have been found below 28 T either on the torque or on the magnetoresistance data. They can be attributed predominantly to orbital effects. Magnetoresistance data obtained up to 55 T show that a transition takes place above 30 T. This transition may be due to the Pauli coupling. The new field-induced density wave state exhibits Shubnikov-de Haas (SdH) oscillations

  8. Quasi-two-dimensional holography

    International Nuclear Information System (INIS)

    Kutzner, J.; Erhard, A.; Wuestenberg, H.; Zimpfer, J.

    1980-01-01

    The acoustical holography with numerical reconstruction by area scanning is memory- and time-intensive. With the experiences by the linear holography we tried to derive a scanning for the evaluating of the two-dimensional flaw-sizes. In most practical cases it is sufficient to determine the exact depth extension of a flaw, whereas the accuracy of the length extension is less critical. For this reason the applicability of the so-called quasi-two-dimensional holography is appropriate. The used sound field given by special probes is divergent in the inclined plane and light focussed in the perpendicular plane using cylindrical lenses. (orig.) [de

  9. Critical phenomena in quasi-two-dimensional vibrated granular systems.

    Science.gov (United States)

    Guzmán, Marcelo; Soto, Rodrigo

    2018-01-01

    The critical phenomena associated to the liquid-to-solid transition of quasi-two-dimensional vibrated granular systems is studied using molecular dynamics simulations of the inelastic hard sphere model. The critical properties are associated to the fourfold bond-orientational order parameter χ_{4}, which measures the level of square crystallization of the system. Previous experimental results have shown that the transition of χ_{4}, when varying the vibration amplitude, can be either discontinuous or continuous, for two different values of the height of the box. Exploring the amplitude-height phase space, a transition line is found, which can be either discontinuous or continuous, merging at a tricritical point and the continuous branch ends in an upper critical point. In the continuous transition branch, the critical properties are studied. The exponent associated to the amplitude of the order parameter is β=1/2, for various system sizes, in complete agreement with the experimental results. However, the fluctuations of χ_{4} do not show any critical behavior, probably due to crossover effects by the close presence of the tricritical point. Finally, in quasi-one-dimensional systems, the transition is only discontinuous, limited by one critical point, indicating that two is the lower dimension for having a tricritical point.

  10. Quasi-two-dimensional thermoelectricity in SnSe

    Science.gov (United States)

    Tayari, V.; Senkovskiy, B. V.; Rybkovskiy, D.; Ehlen, N.; Fedorov, A.; Chen, C.-Y.; Avila, J.; Asensio, M.; Perucchi, A.; di Pietro, P.; Yashina, L.; Fakih, I.; Hemsworth, N.; Petrescu, M.; Gervais, G.; Grüneis, A.; Szkopek, T.

    2018-01-01

    Stannous selenide is a layered semiconductor that is a polar analog of black phosphorus and of great interest as a thermoelectric material. Unusually, hole doped SnSe supports a large Seebeck coefficient at high conductivity, which has not been explained to date. Angle-resolved photoemission spectroscopy, optical reflection spectroscopy, and magnetotransport measurements reveal a multiple-valley valence-band structure and a quasi-two-dimensional dispersion, realizing a Hicks-Dresselhaus thermoelectric contributing to the high Seebeck coefficient at high carrier density. We further demonstrate that the hole accumulation layer in exfoliated SnSe transistors exhibits a field effect mobility of up to 250 cm2/V s at T =1.3 K . SnSe is thus found to be a high-quality quasi-two-dimensional semiconductor ideal for thermoelectric applications.

  11. Few helium atoms in quasi two-dimensional space

    International Nuclear Information System (INIS)

    Kilic, Srecko; Vranjes, Leandra

    2003-01-01

    Two, three and four 3 He and 4 He atoms in quasi two-dimensional space above graphite and cesium surfaces and in 'harmonic' potential perpendicular to the surface have been studied. Using some previously examined variational wave functions and the Diffusion Monte Carlo procedure, it has been shown that all molecules: dimers, trimers and tetramers, are bound more strongly than in pure two- and three-dimensional space. The enhancement of binding with respect to unrestricted space is more pronounced on cesium than on graphite. Furthermore, for 3 He 3 ( 3 He 4 ) on all studied surfaces, there is an indication that the configuration of a dimer and a 'free' particle (two dimers) may be equivalently established

  12. Quasi-Two-Dimensional Magnetism in Co-Based Shandites

    Science.gov (United States)

    Kassem, Mohamed A.; Tabata, Yoshikazu; Waki, Takeshi; Nakamura, Hiroyuki

    2016-06-01

    We report quasi-two-dimensional (Q2D) itinerant electron magnetism in the layered Co-based shandites. Comprehensive magnetization measurements were performed using single crystals of Co3Sn2-xInxS2 (0 ≤ x ≤ 2) and Co3-yFeySn2S2 (0 ≤ y ≤ 0.5). The magnetic parameters of both systems; the Curie temperature TC, effective moment peff and spontaneous moment ps; exhibit almost identical variations against the In- and Fe-concentrations, indicating significance of the electron count on the magnetism in the Co-based shandite. The ferromagnetic-nonmagnetic quantum phase transition is found around xc ˜ 0.8. Analysis based on the extended Q2D spin fluctuation theory clearly reveals the highly Q2D itinerant electron character of the ferromagnetism in the Co-based shandites.

  13. Electrical conductivity of quasi-two-dimensional foams.

    Science.gov (United States)

    Yazhgur, Pavel; Honorez, Clément; Drenckhan, Wiebke; Langevin, Dominique; Salonen, Anniina

    2015-04-01

    Quasi-two-dimensional (quasi-2D) foams consist of monolayers of bubbles squeezed between two narrowly spaced plates. These simplified foams have served successfully in the past to shed light on numerous issues in foam physics. Here we consider the electrical conductivity of such model foams. We compare experiments to a model which we propose, and which successfully relates the structural and the conductive properties of the foam over the full range of the investigated liquid content. We show in particular that in the case of quasi-2D foams the liquid in the nodes needs to be taken into account even at low liquid content. We think that these results may provide different approaches for the characterization of foam properties and for the in situ characterization of the liquid content of foams in confining geometries, such as microfluidics.

  14. Internal optical bistability of quasi-two-dimensional semiconductor nanoheterostructures

    Science.gov (United States)

    Derevyanchuk, Oleksandr V.; Kramar, Natalia K.; Kramar, Valeriy M.

    2018-01-01

    We represent the results of numerical computations of the frequency and temperature domains of possible realization of internal optical bistability in flat quasi-two-dimensional semiconductor nanoheterostructures with a single quantum well (i.e., nanofilms). Particular computations have been made for a nanofilm of layered semiconductor PbI2 embedded in dielectric medium, i.e. ethylene-methacrylic acid (E-MAA) copolymer. It is shown that an increase in the nanofilm's thickness leads to a long-wave shift of the frequency range of the manifestation the phenomenon of bistability, to increase the size of the hysteresis loop, as well as to the expansion of the temperature interval at which the realization of this phenomenon is possible.

  15. Electromagnetic quantum waves and their effect on the low temperature magnetoacoustic response of a quasi-two-dimensional metal

    International Nuclear Information System (INIS)

    Zimbovskaya, Natalya A

    2011-01-01

    We theoretically analyze weakly attenuated electromagnetic waves in quasi-two-dimensional (Q2D) metals in high magnetic fields. Within the chosen geometry, the magnetic field is directed perpendicular to the conducting layers of a Q2D conductor. We have shown that longitudinal collective modes could propagate along the magnetic field provided that the Fermi surface is moderately corrugated. The considered wave speeds strongly depend on the magnetic field magnitude. Also, we have analyzed interactions of these quantum waves with sound waves of suitable polarization and propagation direction, and we have shown that such interaction may bring significant changes to the low temperature magnetoacoustic response of Q2D conductors.

  16. Kinetic Theory of a Confined Quasi-Two-Dimensional Gas of Hard Spheres

    Directory of Open Access Journals (Sweden)

    J. Javier Brey

    2017-02-01

    Full Text Available The dynamics of a system of hard spheres enclosed between two parallel plates separated a distance smaller than two particle diameters is described at the level of kinetic theory. The interest focuses on the behavior of the quasi-two-dimensional fluid seen when looking at the system from above or below. In the first part, a collisional model for the effective two-dimensional dynamics is analyzed. Although it is able to describe quite well the homogeneous evolution observed in the experiments, it is shown that it fails to predict the existence of non-equilibrium phase transitions, and in particular, the bimodal regime exhibited by the real system. A critical revision analysis of the model is presented , and as a starting point to get a more accurate description, the Boltzmann equation for the quasi-two-dimensional gas has been derived. In the elastic case, the solutions of the equation verify an H-theorem implying a monotonic tendency to a non-uniform steady state. As an example of application of the kinetic equation, here the evolution equations for the vertical and horizontal temperatures of the system are derived in the homogeneous approximation, and the results compared with molecular dynamics simulation results.

  17. Segregation in quasi-two-dimensional granular systems

    International Nuclear Information System (INIS)

    Rivas, Nicolas; Cordero, Patricio; Soto, Rodrigo; Risso, Dino

    2011-01-01

    Segregation for two granular species is studied numerically in a vertically vibrated quasi-two-dimensional (quasi-2D) box. The height of the box is smaller than two particle diameters so that particles are limited to a submonolayer. Two cases are considered: grains that differ in their density but have equal size, and grains that have equal density but different diameters, while keeping the quasi-2D condition. It is observed that in both cases, for vibration frequencies beyond a certain threshold-which depends on the density or diameter ratios-segregation takes place in the lateral directions. In the quasi-2D geometry, gravity does not play a direct role in the in-plane dynamics and gravity does not point to the segregation directions; hence, several known segregation mechanisms that rely on gravity are discarded. The segregation we observe is dominated by a lack of equipartition between the two species; the light particles exert a larger pressure than the heavier ones, inducing the latter to form clusters. This energy difference in the horizontal direction is due to the existence of a fixed point characterized by vertical motion and hence vanishing horizontal energy. Heavier and bigger grains are more rapidly attracted to the fixed point and the perturbations are less efficient in taking them off the fixed point when compared to the lighter grains. As a consequence, heavier and bigger grains have less horizontal agitation than lighter ones. Although limited by finite size effects, the simulations suggest that the two cases we consider differ in the transition character: one is continuous and the other is discontinuous. In the cases where grains differ in mass on varying the control parameter, partial segregation is first observed, presenting many clusters of heavier particles. Eventually, a global cluster is formed with impurities; namely lighter particles are present inside. The transition looks continuous when characterized by several segregation order

  18. High magnetic field magnetoresistance anomalies in the charge density wave state of the quasi-two dimensional bronze KMo6O{17}

    Science.gov (United States)

    Guyot, H.; Dumas, J.; Marcus, J.; Schlenker, C.; Vignolles, D.

    2005-12-01

    We report high magnetic field magnetoresistance measurements performed in pulsed fields up to 55 T on the quasi-two dimensional charge density wave conductor KMo{6}O{17}. Magnetoresistance curves show several anomalies below 28 T. First order transitions to smaller gap states take place at low temperature above 30 T. A phase diagram T(B) has been obtained. The angular dependence of the anomalies is reported.

  19. Crucial role of sidewalls in velocity distributions in quasi-two-dimensional granular gases

    NARCIS (Netherlands)

    van Zon, J.S.; Kreft, J.; Goldman, D.L.; Miracle, D.; Swift, J. B.; Swinney, H. L.

    2004-01-01

    The significance of sidewalls which yield velocity distributions with non-Gaussian tails and a peak near zero velocity in quasi-two-dimensional granular gases, was investigated. It was observed that the particles gained energy only through collisions with the bottom of the container, which was not

  20. Low-temperature specific heat of the quasi-two-dimensional charge-density wave compound KMo6O17

    Science.gov (United States)

    Wang, Junfeng; Xiong, Rui; Yin, Di; Li, Changzhen; Tang, Zheng; Wang, Ququan; Shi, Jing; Wang, Yue; Wen, Haihu

    2006-05-01

    Low temperature specific heat (Cp) of quasi-two-dimensional charge-density wave (CDW) compound KMo6O17 has been studied by a relaxation method from 2to48K under zero and 12T magnetic fields. The results show that no specific heat anomaly is found at 16K under both zero and 12T magnetic fields, although an anomaly is clearly observed in the resistivity and magnetoresistance measurements. From the data between 2 and 4K , the density of states at Fermi level is estimated as 0.2eV-1permolecule and the Debye temperature is extracted to be 418K . A bump appearing in Cp/T3 is found between 4 and 48K centered around 12.5-15K , indicating that the phason excitations contribute to the total specific heat similarly as in quasi-one-dimensional CDW conductors. Using a modified Debye model, a pinning frequency of 0.73THz for KMo6O17 is estimated from the phason contribution.

  1. Orbital effect for the Fulde-Ferrell-Larkin-Ovchinnikov phase in a quasi-two-dimensional superconductor in a parallel magnetic field

    Science.gov (United States)

    Lebed, A. G.

    2018-04-01

    We theoretically study the orbital destructive effect against superconductivity in a parallel magnetic field in the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO or LOFF) phase at zero temperature in a quasi-two-dimensional (Q2D) conductor. We demonstrate that at zero temperature a special parameter, λ =l⊥(H ) /d , is responsible for strength of the orbital effect, where l⊥(H ) is a typical "size" of the quasiclassical electron orbit in a magnetic field and d is the interplane distance. We discuss applications of our results to the existing experiments on the FFLO phase in the organic Q2D conductors κ -(ET) 2Cu (NCS) 2 and κ -(ET) 2Cu [N (CN) 2] Cl .

  2. Quasi-two-dimensional metallic hydrogen in diphosphide at a high pressure

    International Nuclear Information System (INIS)

    Degtyarenko, N. N.; Mazur, E. A.

    2016-01-01

    The structural, electronic, phonon, and other characteristics of the normal phases of phosphorus hydrides with stoichiometry PH k are analyzed. The properties of the initial substance, namely, diphosphine are calculated. In contrast to phosphorus hydrides with stoichiometry PH 3 , a quasi-two-dimensional phosphorus-stabilized lattice of metallic hydrogen can be formed in this substance during hydrostatic compression at a high pressure. The formed structure with H–P–H elements is shown to be locally stable in phonon spectrum, i.e., to be metastable. The properties of diphosphine are compared with the properties of similar structures of sulfur hydrides.

  3. Boundary effects in a quasi-two-dimensional driven granular fluid.

    Science.gov (United States)

    Smith, N D; Smith, M I

    2017-12-01

    The effect of a confining boundary on the spatial variations in granular temperature of a driven quasi-two-dimensional layer of particles is investigated experimentally. The radial drop in the relative granular temperature ΔT/T exhibits a maximum at intermediate particle numbers which coincides with a crossover from kinetic to collisional transport of energy. It is also found that at low particle numbers, the distributions of radial velocities are increasingly asymmetric as one approaches the boundary. The radial and tangential granular temperatures split, and in the tails of the radial velocity distribution there is a higher population of fast moving particles traveling away rather than towards the boundary.

  4. Quasi-two-dimensional complex plasma containing spherical particles and their binary agglomerates.

    Science.gov (United States)

    Chaudhuri, M; Semenov, I; Nosenko, V; Thomas, H M

    2016-05-01

    A unique type of quasi-two-dimensional complex plasma system was observed which consisted of monodisperse microspheres and their binary agglomerations (dimers). The particles and their dimers levitated in a plasma sheath at slightly different heights and formed two distinct sublayers. The system did not crystallize and may be characterized as a disordered solid. The dimers were identified based on their characteristic appearance in defocused images, i.e., rotating interference fringe patterns. The in-plane and interplane particle separations exhibit nonmonotonic dependence on the discharge pressure.

  5. Hall Conductivity in a Quasi-Two-Dimensional Disordered Electron System

    Institute of Scientific and Technical Information of China (English)

    YANG Yong-Hong; WANG Yong-Gang; LIU Mei

    2002-01-01

    By making use of the diagrammatic techniques in perturbation theory,we have investigated the Hall effect in a quasi-two-dimensional disordered electron system.In the weakly localized regime,the analytical expression for quantum correction to Hall conductivity has been obtained using the Kubo formalism and quasiclassical approximation.The relevant dimensional crossover behavior from three dimensions to two dimensions with decreasing the interlayer hopping energy is discussed.The quantum interference effect is shown to have a vanishing correction t,o the Hall coefficient.

  6. Elementary excitations and quasi-two-dimensional behaviour in a GaAs field effect transistor

    International Nuclear Information System (INIS)

    Tomak, M.; Sernelius, B.E.; Berggren, K.F.

    1983-09-01

    The elementary excitation modes in a narrow channel of conducting electrons in a special GaAs FET are evaluated within the RPA-approximation. The system is found to be quasi-two-dimensional when the width of the channel is small, i.e. there are collective excitations with a dispersion very close to the strictly 2D form. In addition to the low-lying quasi-2D-mode there are higher collective modes associated with the sub-band structure of the device. (author)

  7. Thermoelectric power and topological transitions in quasi-two-dimensional electronic systems

    International Nuclear Information System (INIS)

    Blanter, Ya.M.; Pantsulaya, A.V.; Varlamov, A.A.

    1991-05-01

    Electron-impurity relaxation time and the thermoelectric power (TEP) of quasi-two-dimensional electron gas are calculated. Two cases are discussed: the isotropic spectrum and the electronic topological transition (ETT) of the ''neck-breaking'' type. Methods of thermal diagramatic technique are used for the calculation. It is found that the TEP in the vicinity of the ETT greatly exceeds its background value. The results of experimental investigations of the TEP in the metal-oxide-semiconductor structures are compared with the predictions of the proposed theory. (author). 17 refs, 5 figs

  8. Transient response in granular quasi-two-dimensional bounded heap flow.

    Science.gov (United States)

    Xiao, Hongyi; Ottino, Julio M; Lueptow, Richard M; Umbanhowar, Paul B

    2017-10-01

    We study the transition between steady flows of noncohesive granular materials in quasi-two-dimensional bounded heaps by suddenly changing the feed rate. In both experiments and simulations, the primary feature of the transition is a wedge of flowing particles that propagates downstream over the rising free surface with a wedge front velocity inversely proportional to the square root of time. An additional longer duration transient process continues after the wedge front reaches the downstream wall. The entire transition is well modeled as a moving boundary problem with a diffusionlike equation derived from local mass balance and a local relation between the flux and the surface slope.

  9. Quasi-two-dimensional metallic hydrogen in diphosphide at a high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Degtyarenko, N. N.; Mazur, E. A., E-mail: eugen-mazur@mail.ru [National Research Nuclear University MEPhI (Russian Federation)

    2016-08-15

    The structural, electronic, phonon, and other characteristics of the normal phases of phosphorus hydrides with stoichiometry PH{sub k} are analyzed. The properties of the initial substance, namely, diphosphine are calculated. In contrast to phosphorus hydrides with stoichiometry PH{sub 3}, a quasi-two-dimensional phosphorus-stabilized lattice of metallic hydrogen can be formed in this substance during hydrostatic compression at a high pressure. The formed structure with H–P–H elements is shown to be locally stable in phonon spectrum, i.e., to be metastable. The properties of diphosphine are compared with the properties of similar structures of sulfur hydrides.

  10. Complex Quasi-Two-Dimensional Crystalline Order Embedded in VO2 and Other Crystals

    Science.gov (United States)

    Lovorn, Timothy; Sarker, Sanjoy K.

    2017-07-01

    Metal oxides such as VO2 undergo structural transitions to low-symmetry phases characterized by intricate crystalline order, accompanied by rich electronic behavior. We derive a minimal ionic Hamiltonian based on symmetry and local energetics which describes structural transitions involving all four observed phases, in the correct order. An exact analysis shows that complexity results from the symmetry-induced constraints of the parent phase, which forces ionic displacements to form multiple interpenetrating groups using low-dimensional pathways and distant neighbors. Displacements within each group exhibit independent, quasi-two-dimensional order, which is frustrated and fragile. This selective ordering mechanism is not restricted to VO2 : it applies to other oxides that show similar complex order.

  11. Absorption imaging of a quasi-two-dimensional gas: a multiple scattering analysis

    International Nuclear Information System (INIS)

    Chomaz, L; Corman, L; Yefsah, T; Desbuquois, R; Dalibard, J

    2012-01-01

    Absorption imaging with quasi-resonant laser light is a commonly used technique for probing ultra-cold atomic gases in various geometries. In this paper, we investigate some non-trivial aspects of this method when applying the method to in situ diagnosis of a quasi-two-dimensional (2D) gas. Using Monte Carlo simulations we study the modification of the absorption cross-section of a photon when it undergoes multiple scattering in the gas. We determine the variations of the optical density with various parameters, such as the detuning of the light from the atomic resonance and the thickness of the gas. We compare our results to the known 3D result (the Beer-Lambert law) and outline the specific features of the 2D case. (paper)

  12. Electron-phonon heat exchange in quasi-two-dimensional nanolayers

    Science.gov (United States)

    Anghel, Dragos-Victor; Cojocaru, Sergiu

    2017-12-01

    We study the heat power P transferred between electrons and phonons in thin metallic films deposited on free-standing dielectric membranes. The temperature range is typically below 1 K, such that the wavelengths of the excited phonon modes in the system is large enough so that the picture of a quasi-two-dimensional phonon gas is applicable. Moreover, due to the quantization of the components of the electron wavevectors perpendicular to the metal film's surface, the electrons spectrum forms also quasi two-dimensional sub-bands, as in a quantum well (QW). We describe in detail the contribution to the electron-phonon energy exchange of different electron scattering channels, as well as of different types of phonon modes. We find that heat flux oscillates strongly with thickness of the film d while having a much smoother variation with temperature (Te for the electrons temperature and Tph for the phonons temperature), so that one obtains a ridge-like landscape in the two coordinates, (d, Te) or (d, Tph), with crests and valleys aligned roughly parallel to the temperature axis. For the valley regions we find P ∝ Te3.5 - Tph3.5. From valley to crest, P increases by more than one order of magnitude and on the crests P cannot be represented by a simple power law. The strong dependence of P on d is indicative of the formation of the QW state and can be useful in controlling the heat transfer between electrons and crystal lattice in nano-electronic devices. Nevertheless, due to the small value of the Fermi wavelength in metals, the surface imperfections of the metallic films can reduce the magnitude of the oscillations of P vs. d, so this effect might be easier to observe experimentally in doped semiconductors.

  13. Many-particle correlations in quasi-two-dimensional electron-hole systems

    International Nuclear Information System (INIS)

    Nikolaev, Valentin

    2002-01-01

    This thesis reports a theoretical investigation of many-particle correlation effects in semiconductor heterostructures containing quantum wells. Particular attention is paid towards quasi-particle pair correlations. Using the Green's function technique and the ladder approximation as a basis, the generalized mass action law, which describes the redistribution of particles between correlated and uncorrelated states in quasi-two-dimensional systems for different temperatures and total densities, is derived. The expression is valid beyond the low-density limit, which allows us to investigate the transition of the system from a dilute exciton gas to a dense electron-hole plasma. A generalized Levinson theorem, which takes k-space filling into account, is formulated. Screening in quasi-two-dimensional systems is analyzed rigorously. Firstly, the qualitatively new mechanism of static local screening by indirect excitons is studied using the simple Thomas-Fermi approximation. Then, a detailed many-body description suitable for a proper account of dynamic screening by a quasi-2D electron-hole plasma, and consistent with the previously derived mass action law, is provided. The generalized Lindhard approximation and excitonic plasmon-pole approximations are also derived. The theory is applied to single and double quantum wells. A self-consistent procedure is developed for numerical investigation of the ionization degree of an electron-hole plasma at different values of temperature/exciton Rydberg ratios. This procedure accounts for screening, k-space filling (exciton bleaching), and the formation of excitons. An abrupt jump in the value of the ionization degree that happens with an increase of the carrier density or temperature (Mott transition) is found in a certain density-temperature region. It has been found that the critical density of the Mott transition for indirect excitons may be much smaller than that for direct excitons. A suggestion has been made that some of the

  14. Experimental investigations of superconductivity in quasi-two-dimensional epitaxial copper oxide superlattices and trilayers

    International Nuclear Information System (INIS)

    Lowndes, D.H.; Norton, D.P.

    1993-01-01

    Epitaxial trilayer and superlattice structures grown by pulsed laser ablation have been used to study the superconducting-to-normal transition of ultrathin (one and two c-axis unit cells) YBa 2 Cu 3 O 7-x layers. The normalized flux-flow resistances for several epitaxial structures containing two-cell-thick YBa 2 Cu 3 O 7-x films collapse onto the ''universal'' curve of the Ginzburg-Landau Coulomb Gas (GLCG) model. Analysis of normalized resistance data for a series of superlattices containing one-cell-thick YBa 2 Cu 3 O 7-x layers also is consistent with the behavior expected for quasi-two-dimensional layers in a highly anisotropic, layered three-dimensional superconductor. Current-voltage measurements for one of the trilayer structures also are consistent with the normalized resistance data, and with the GLCG model. Scanning tunneling microscopy, transmission electron microscopy, and electrical transport studies show that growth-related steps in ultrathin YBa 2 Cu 3 O 7-x layers affect electrical continuity over macroscopic distances, acting as weak links. However , the perturbation of the superconducting order parameter can be minimized by utilizing hole-doped buffer and cap layers, on both sides of the YBa 2 Cu 3 O 7-x layer, in trilayers and superlattices. These results demonstrate the usefulness of epitaxial trilayer and superlattice structures as tools for systematic, fundamental studies of high-temperature superconductivity

  15. Origin of Hund's multiplicity rule in quasi-two-dimensional two-electron quantum dots

    International Nuclear Information System (INIS)

    Sako, Tokuei; Paldus, Josef; Diercksen, Geerd H. F.

    2010-01-01

    The origin of Hund's multiplicity rules has been studied for a system of two electrons confined by a quasi-two-dimensional harmonic-oscillator potential by relying on a full configuration interaction wave function and Cartesian anisotropic Gaussian basis sets. In terms of appropriate normal-mode coordinates the wave function factors into a product of the center-of-mass and the internal components. The 1 Π u singlet state and the 3 Π u triplet state represent the energetically lowest pair of states to which Hund's multiplicity rule applies. They are shown to involve excitations into different degrees of freedom, namely, into the center-of-mass angular mode and the internal angular mode for the singlet and triplet states, respectively. The presence of an angular nodal line in the internal space allows then the triplet state to avoid the singularity in the electron-electron interaction potential, leading to the energy lowering of the triplet state relative to its counterpart singlet state.

  16. Complexes of dipolar excitons in layered quasi-two-dimensional nanostructures

    Science.gov (United States)

    Bondarev, Igor V.; Vladimirova, Maria R.

    2018-04-01

    We discuss neutral and charged complexes (biexcitons and trions) formed by indirect excitons in layered quasi-two-dimensional semiconductor heterostructures. Indirect excitons—long-lived neutral Coulomb-bound pairs of electrons and holes of different layers—have been known for semiconductor coupled quantum wells and have recently been reported for van der Waals heterostructures such as double bilayer graphene and transition-metal dichalcogenides. Using the configuration space approach, we derive the analytical expressions for the trion and biexciton binding energies as a function of interlayer distance. The method captures essential kinematics of complex formation to reveal significant binding energies, up to a few tens of meV for typical interlayer distances ˜3 -5 Å , with the trion binding energy always being greater than that of the biexciton. Our results can contribute to the understanding of more complex many-body phenomena such as exciton Bose-Einstein condensation and Wigner-like electron-hole crystallization in layered semiconductor heterostructures.

  17. Generation of acoustic phonons from quasi-two-dimensional hole gas

    International Nuclear Information System (INIS)

    Singh, J.; Oh, I.K.

    2002-01-01

    Full text: Generation of phonons from two dimensional electron and hole gases in quantum wells has attracted much attraction recently. The mechanism of phonon emission plays an important role in the phonon spectroscopy which enables us to study the angular and polarization dependence of phonon emission. The acoustic phonon emission from a quasi-two-dimensional hole gas (2DHG) in quantum wells is influenced by the anisotropic factors in the valence band structure, screening, elastic property, etc. The anisotropy in the valence band structure gives rise to anisotropic effective mass and deformation potential and that in the elastic constants leads to anisotropic sound velocity. Piezoelectric coupling in non-centrosymmetric materials such as GaAs is also anisotropic. In this paper, considering the anisotropy in the effective mass, deformation potential, piezoelectric coupling and screening effect, we present a theory to study the angular and polarization dependence of acoustic phonon emission from a quasi-2DHG in quantum wells. The theory is finally applied to calculate the rate of acoustic phonon emission in GaAs quantum wells

  18. Dipolar local field in homogeneously magnetized quasi-two-dimensional crystals

    International Nuclear Information System (INIS)

    Leon, H; Estevez-Rams, E

    2009-01-01

    A formalism to calculate the dipolar local field in homogeneously magnetized quasi-two-dimensional (Q2D) crystals is comprehensively presented. Two fundamental tests for this formalism are accomplished: the transition from the Q2D quantities to the corresponding 3D ones; and the recovering of the macroscopic quantities of the 3D continuum theory. The additive separation between lattice and shape contributions to the local field allows an unambiguous interpretation of the respective effects. Calculated demagnetization tensors for square and circular lateral geometries of dipole layers show that for a single crystal layer an extremely thin film, but still with a finite thickness, is a better physical representation than a strictly 2D plane. Distinct close-packed structures are simulated and calculations of the local field at the nodes of the stacked 2D lattices allow one to establish the number of significantly coupled dipole layers, depending on the ratio between the interlayer distance and the 2D lattice constant. The conclusions drawn are of interest for the study of the dipolar interaction in magnetic ultrathin films and other nanostructured materials, where magnetic nanoparticles are embedded in non-magnetic matrices.

  19. Coupling motion of colloidal particles in quasi-two-dimensional confinement

    International Nuclear Information System (INIS)

    Ma, Jun; Jing, Guangyin

    2014-01-01

    The Brownian motion of colloidal particles in quasi-two-dimensional (q2D) confinement displays a distinct kinetic character from that in bulk. Here we experimentally report dynamic coupling motion of Brownian particles in a relatively long process (∼100 h), which displays a quasi-equilibrium state in the q2D system. In the quasi-equilibrium state, the q2D confinement results in the coupling of particle motions, which slowly damps the motion and interaction of particles until the final equilibrium state is reached. The process of approaching the equilibrium is a random relaxation of a many-body interaction system of Brownian particles. As the relaxation proceeds for ∼100 h, the system reaches the equilibrium state in which the energy gained by the particles from the stochastic collision in the whole system is counteracted by the dissipative energy resulting from the collision. The relaxation time of this stochastic q2D system is 17.7 h. The theory is developed to explain coupling motions of Brownian particles in q2D confinement. (paper)

  20. Vibrational properties of quasi-two-dimensional colloidal glasses with varying interparticle attraction.

    Science.gov (United States)

    Gratale, Matthew D; Ma, Xiaoguang; Davidson, Zoey S; Still, Tim; Habdas, Piotr; Yodh, A G

    2016-10-01

    We measure the vibrational modes and particle dynamics of quasi-two-dimensional colloidal glasses as a function of interparticle interaction strength. The interparticle attractions are controlled via a temperature-tunable depletion interaction. Specifically, the interparticle attraction energy is increased gradually from a very small value (nearly hard-sphere) to moderate strength (∼4k_{B}T), and the variation of colloidal particle dynamics and vibrations are concurrently probed. The particle dynamics slow monotonically with increasing attraction strength, and the particle motions saturate for strengths greater than ∼2k_{B}T, i.e., as the system evolves from a nearly repulsive glass to an attractive glass. The shape of the phonon density of states is revealed to change with increasing attraction strength, and the number of low-frequency modes exhibits a crossover for glasses with weak compared to strong interparticle attraction at a threshold of ∼2k_{B}T. This variation in the properties of the low-frequency vibrational modes suggests a new means for distinguishing between repulsive and attractive glass states.

  1. Correlation induced electron-hole asymmetry in quasi- two-dimensional iridates.

    Science.gov (United States)

    Pärschke, Ekaterina M; Wohlfeld, Krzysztof; Foyevtsova, Kateryna; van den Brink, Jeroen

    2017-09-25

    The resemblance of crystallographic and magnetic structures of the quasi-two-dimensional iridates Ba 2 IrO 4 and Sr 2 IrO 4 to La 2 CuO 4 points at an analogy to cuprate high-Tc superconductors, even if spin-orbit coupling is very strong in iridates. Here we examine this analogy for the motion of a charge (hole or electron) added to the antiferromagnetic ground state. We show that correlation effects render the hole and electron case in iridates very different. An added electron forms a spin polaron, similar to the cuprates, but the situation of a removed electron is far more complex. Many-body 5d 4 configurations form which can be singlet and triplet states of total angular momentum that strongly affect the hole motion. This not only has ramifications for the interpretation of (inverse-)photoemission experiments but also demonstrates that correlation physics renders electron- and hole-doped iridates fundamentally different.Some iridate compounds such as Sr 2 IrO 4 have electronic and atomic structures similar to quasi-2D copper oxides, raising the prospect of high temperature superconductivity. Here, the authors show that there is significant electron-hole asymmetry in iridates, contrary to expectations from the cuprates.

  2. Long-lived trimers in a quasi-two-dimensional Fermi system

    Science.gov (United States)

    Laird, Emma K.; Kirk, Thomas; Parish, Meera M.; Levinsen, Jesper

    2018-04-01

    We consider the problem of three distinguishable fermions confined to a quasi-two-dimensional (quasi-2D) geometry, where there is a strong harmonic potential in one direction. We go beyond previous theoretical work and investigate the three-body bound states (trimers) for the case where the two-body short-range interactions between fermions are unequal. Using the scattering parameters from experiments on ultracold 6Li atoms, we calculate the trimer spectrum throughout the crossover from two to three dimensions. We find that the deepest Efimov trimer in the 6Li system is unaffected by realistic quasi-2D confinements, while the first excited trimer smoothly evolves from a three-dimensional-like Efimov trimer to an extended 2D-like trimer as the attractive interactions are decreased. We furthermore compute the excited trimer wave function and quantify the stability of the trimer against decay into a dimer and an atom by determining the probability that three fermions approach each other at short distances. Our results indicate that the lifetime of the trimer can be enhanced by at least an order of magnitude in the quasi-2D geometry, thus opening the door to realizing long-lived trimers in three-component Fermi gases.

  3. General solution of the Dirac equation for quasi-two-dimensional electrons

    Energy Technology Data Exchange (ETDEWEB)

    Eremko, Alexander, E-mail: eremko@bitp.kiev.ua [Bogolyubov Institute for Theoretical Physics, Metrologichna Str., 14-b, Kyiv, 03680 (Ukraine); Brizhik, Larissa, E-mail: brizhik@bitp.kiev.ua [Bogolyubov Institute for Theoretical Physics, Metrologichna Str., 14-b, Kyiv, 03680 (Ukraine); Loktev, Vadim, E-mail: vloktev@bitp.kiev.ua [Bogolyubov Institute for Theoretical Physics, Metrologichna Str., 14-b, Kyiv, 03680 (Ukraine); National Technical University of Ukraine “KPI”, Peremohy av., 37, Kyiv, 03056 (Ukraine)

    2016-06-15

    The general solution of the Dirac equation for quasi-two-dimensional electrons confined in an asymmetric quantum well, is found. The energy spectrum of such a system is exactly calculated using special unitary operator and is shown to depend on the electron spin polarization. This solution contains free parameters, whose variation continuously transforms one known particular solution into another. As an example, two different cases are considered in detail: electron in a deep and in a strongly asymmetric shallow quantum well. The effective mass renormalized by relativistic corrections and Bychkov–Rashba coefficients are analytically obtained for both cases. It is demonstrated that the general solution transforms to the particular solutions, found previously (Eremko et al., 2015) with the use of spin invariants. The general solution allows to establish conditions at which a specific (accompanied or non-accompanied by Rashba splitting) spin state can be realized. These results can prompt the ways to control the spin degree of freedom via the synthesis of spintronic heterostructures with the required properties.

  4. Quasi-two-dimensional Fermi-liquid state in Sr2RhO4-δ

    International Nuclear Information System (INIS)

    Nagai, Ichiro; Shirakawa, Naoki; Umeyama, Norio; Ikeda, Shin-ichi

    2010-01-01

    Single crystals of layered perovskite Sr 2 RhO 4-δ (δ=0.0 and 0.1) are successfully grown by the floating-zone method. Stoichiometric single crystals (Sr 2 RhO 4.0 ) are obtained by O 2 -annealing the as-grown crystals (Sr 2 RhO 3.9 ). Sr 2 RhO 4.0 and Sr 2 RhO 3.9 show quasi-two-dimensional Fermi-liquid behavior at low temperatures, whereas there are large differences in the anisotropy of electrical resistivity ρ c (3 K)/ρ ab (3 K) and Wilson ratio R w between Sr 2 RhO 4.0 and Sr 2 RhO 3.9 : ρ c (3 K)/ρ ab (3 K)=2400 (19000) and R w =3.8 (6.4) for Sr 2 RhO 4.0 (Sr 2 RhO 3.9 ). The differences observed between the temperature dependence of the in-plane electrical resistivity (T 2 RhO 4.0 and Sr 2 RhO 3.9 are mainly derived from those between the density of states and band structure near the corresponding Fermi level. This indicates that the changes in these physical properties, which are accompanied by oxygen defects in the Sr 2 RhO 4-δ system, can be explained by the rigid band model. Moreover, these results suggest that t 2g band-filling can be controlled by adjusting the oxygen defect content δ in the Sr 2 RhO 4-δ system. Although many similarities are observed in this study between the physical properties of Sr 2 RhO 4.0 and Sr 2 RuO 4 . Sr 2 RhO 4.0 does not exhibit superconductivity down to 36 mK. (author)

  5. Molecular dynamics studies of superionic conductors

    International Nuclear Information System (INIS)

    Rahman, A.; Vashishta, P.

    1983-01-01

    Structural and dynamical properties of superionic conductors AgI and CuI are studied using molecular dynamics (MD) techniques. The model of these superionic conductors is based on the use of effective pair potentials. To determine the constants in these potentials, cohesive energy and bulk modulus are used as input: in addition one uses notions of ionic size based on the known crystal structure. Salient features of the MD technique are outlined. Methods of treating long range Coulomb forces are discussed in detail. This includes the manner of doing Ewald sum for MD cells of arbitrary shape. Features that can be incorporated to expedite the MD calculations are also discussed. A novel MD technique which allows for a dynamically controlled variation of the shape and size of the MD cell is described briefly. The development of this novel technique has made it possible to study structural phase transitions in superionic conductors. 68 references, 17 figures, 2 tables

  6. First-principles study of hydrogen-bonded molecular conductor κ -H3(Cat-EDT-TTF/ST)2

    Science.gov (United States)

    Tsumuraya, Takao; Seo, Hitoshi; Kato, Reizo; Miyazaki, Tsuyoshi

    2015-07-01

    We theoretically study hydrogen-bonded molecular conductors synthesized recently, κ -H3(Cat-EDT-TTF) 2 and its diselena analog, κ -H3(Cat-EDT-ST) 2, by first-principles density functional theory calculations. In these crystals, two H(Cat-EDT-TTF/ST) units share a hydrogen atom with a short O-H-O hydrogen bond. The calculated band structure near the Fermi level shows a quasi-two-dimensional character with a rather large interlayer dispersion due to the absence of insulating layers, in contrast with conventional molecular conductors. We discuss effective low-energy models based on H(Cat-EDT-TTF/ST) units and its dimers, respectively, where the microscopic character of the orbitals composing them are analyzed. Furthermore, we find a stable structure which is different from the experimentally determined structure, where the shared hydrogen atom becomes localized to one of the oxygen atoms, in which charge disproportionation between the two types of H(Cat-EDT-TTF) units is associated. The calculated potential energy surface for the H atom is very shallow near the minimum points; therefore the probability of the H atom can be delocalized between the two O atoms.

  7. Three-particle correlation functions of quasi-two-dimensional one-component and binary colloid suspensions.

    Science.gov (United States)

    Ho, Hau My; Lin, Binhua; Rice, Stuart A

    2006-11-14

    We report the results of experimental determinations of the triplet correlation functions of quasi-two-dimensional one-component and binary colloid suspensions in which the colloid-colloid interaction is short ranged. The suspensions studied range in density from modestly dilute to solid. The triplet correlation function of the one-component colloid system reveals extensive ordering deep in the liquid phase. At the same density the ordering of the larger diameter component in a binary colloid system is greatly diminished by a very small amount of the smaller diameter component. The possible utilization of information contained in the triplet correlation function in the theory of melting of a quasi-two-dimensional system is briefly discussed.

  8. PREFACE: International Symposium on Molecular Conductors: Novel Functions of Molecular Conductors under Extreme Conditions (ISMC 2008)

    Science.gov (United States)

    Takahashi, Toshihiro; Suzumura, Yoshikazu

    2008-02-01

    The International Symposium on Molecular Conductors 2008 (ISMC2008) was held as the second international symposium of the project entitled `Novel Functions of Molecular Conductors under Extreme Conditions', which was supported by the Grant-in-aid for Scientific Research on Priority Areas from the Ministry of Education, Culture, Sports, Science and Technology in Japan. The project lasted from September 2003 to March 2008, and was completed by this symposium held at Okazaki Conference Center, Institute for Molecular Science, Okazaki, Japan (23-25 July 2008), which about 100 scientists attended. During the symposium, five project teams gave summary talks and exciting talks were given on the topics developed recently not only by the members of the project but also by other scientists including invited speakers from abroad, who are doing active research on molecular conductors. It is expected that papers presented in the symposium will give valuable hints for the next step in the research of this field. Therefore the organizers of this symposium decided to publish this proceedings in order to demonstrate these activities, not only for the local community of the project, but also for the broad society of international scientists who are interested in molecular conductors. The editors, who are also the organizers of this symposium, believe that this proceedings provides a significant and relevant contribution to the field of molecular conductors since it is the first time we have published such a proceedings as an electronic journal. We note that all papers published in this volume of Journal of Physics: Conference Series have been peer reviewed by expert referees. Editors made every effort to satisfy the criterion of a proceedings journal published by IOP Publishing. Toshihiro Takahashi and Yoshikazu Suzumura Editors: Toshihiro Takahashi (Gakushuin University) (Chairman) Kazushi Kanoda (University of Tokyo) Seiichi Kagoshima (University of Tokyo) Takehiko Mori (Tokyo

  9. Electroluminescence of colloidal quasi-two-dimensional semiconducting CdSe nanostructures in a hybrid light-emitting diode

    Energy Technology Data Exchange (ETDEWEB)

    Selyukov, A. S., E-mail: vslebedev.mobile@gmail.com; Vitukhnovskii, A. G.; Lebedev, V. S.; Vashchenko, A. A. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Vasiliev, R. B.; Sokolikova, M. S. [Moscow State University (Russian Federation)

    2015-04-15

    We report on the results of studying quasi-two-dimensional nanostructures synthesized here in the form of semiconducting CdSe nanoplatelets with a characteristic longitudinal size of 20–70 nm and a thick-ness of a few atomic layers. Their morphology is studied using TEM and AFM and X-ray diffraction analysis; the crystal structure and sizes are determined. At room and cryogenic temperatures, the spectra and kinetics of the photoluminescence of such structures (quantum wells) are investigated. A hybrid light-emitting diode operating on the basis of CdSe nanoplatelets as a plane active element (emitter) is developed using the organic materials TAZ and TPD to form electron and hole transport layers, respectively. The spectral and current-voltage characteristics of the constructed device with a radiation wavelength λ = 515 nm are obtained. The device triggering voltage is 5.5 V (visible glow). The use of quasi-two-dimensional structures of this type is promising for hybrid light-emitting diodes with pure color and low operating voltages.

  10. Electroluminescence of colloidal quasi-two-dimensional semiconducting CdSe nanostructures in a hybrid light-emitting diode

    International Nuclear Information System (INIS)

    Selyukov, A. S.; Vitukhnovskii, A. G.; Lebedev, V. S.; Vashchenko, A. A.; Vasiliev, R. B.; Sokolikova, M. S.

    2015-01-01

    We report on the results of studying quasi-two-dimensional nanostructures synthesized here in the form of semiconducting CdSe nanoplatelets with a characteristic longitudinal size of 20–70 nm and a thick-ness of a few atomic layers. Their morphology is studied using TEM and AFM and X-ray diffraction analysis; the crystal structure and sizes are determined. At room and cryogenic temperatures, the spectra and kinetics of the photoluminescence of such structures (quantum wells) are investigated. A hybrid light-emitting diode operating on the basis of CdSe nanoplatelets as a plane active element (emitter) is developed using the organic materials TAZ and TPD to form electron and hole transport layers, respectively. The spectral and current-voltage characteristics of the constructed device with a radiation wavelength λ = 515 nm are obtained. The device triggering voltage is 5.5 V (visible glow). The use of quasi-two-dimensional structures of this type is promising for hybrid light-emitting diodes with pure color and low operating voltages

  11. Magnetic structure of the quasi-two-dimensional compound CoTa{sub 2}O{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Kinast, E.J. [Universidade Estadual do Rio Grande do Sul, Rua 7 de Setembro, 1156, 90010-191 Porto Alegre (Brazil); Santos, C.A. dos [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, C.P. 15051, 91501-970 Porto Alegre (Brazil); Schmitt, D. [Laboratoire de Geophysique Interne et Tectonophysique, Universite Joseph Fourier, B. P. 53, 38041 Grenoble Cedex 9 (France); Isnard, O., E-mail: olivier.isnard@grenoble.cnrs.f [Institut Neel, CNRS/Universite Jospeh Fourier, avenue des martyrs B. P. 166, 38042 Grenoble Cedex 9 (France); Gusmao, M.A.; Cunha, J.B.M. da [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, C.P. 15051, 91501-970 Porto Alegre (Brazil)

    2010-02-18

    We report on a detailed investigation of magnetic properties of CoTa{sub 2}O{sub 6} using several techniques: neutron and X-ray diffraction, specific-heat, magnetic susceptibility, and magnetization measurements. The compound shows quasi-two-dimensional behavior due to its layered structure of alternating Co-O and Ta-O planes. We find that all magnetic moments lie entirely in the Co-O planes, along easy axes determined by the orientations of oxygen octahedra that surround the Co ions. The easy axes in successive magnetic planes have relative orientations that differ by 90{sup o}. Antiferromagnetic ordering is observed below 6.6 K, with propagation vectors ({+-}1/4,1/4,1/4) associated to the two non-equivalent sets of Co{sup 2+} ions, whose magnetic moments are perpendicularly oriented.

  12. Absence of effects of an in-plane magnetic field in a quasi-two-dimensional electron system

    Science.gov (United States)

    Brandt, F. T.; Sánchez-Monroy, J. A.

    2018-03-01

    The dynamics of a quasi-two-dimensional electron system (q2DES) in the presence of a tilted magnetic field is reconsidered employing the thin-layer method. We derive the effective equations for relativistic and nonrelativistic q2DESs. Through a perturbative expansion, we show that while the magnetic length is much greater than the confinement width, the in-plane magnetic field only affects the particle dynamics through the spin. Therefore, effects due to an in-plane magnetic vector potential reported previously in the literature for 2D quantum rings, 2D quantum dots and graphene are fictitious. In particular, the so-called pseudo chiral magnetic effect recently proposed in graphene is not realistic.

  13. Spin-Dependent Scattering Effects and Dimensional Crossover in a Quasi-Two-Dimensional Disordered Electron System

    Institute of Scientific and Technical Information of China (English)

    YANG YongHong; WANG YongGang; LIU Mei; WANG Jin

    2002-01-01

    Two kinds of spin-depcndcnt scattering effects (magnetic-iinpurity and spin-orbit scatterings) axe investi-gated theoretically in a quasi-two-dimensional (quasi-2D) disordered electron system. By making use of the diagrammatictechniques in perturbation theory, we have calculated the dc conductivity and magnetoresistance due to weak-localizationeffects, the analytical expressions of them are obtained as functions of the interlayer hopping energy and the charac-teristic times: elastic, inelastic, magnetic and spin-orbit scattering times. The relevant dimensional crossover behaviorfrom 3D to 2D with decreasing the interlayer coupling is discussed, and the condition for the crossover is shown to bedependent on the aforementioned scattering times. At low temperature there exists a spin-dcpendent-scattering-induccddimensional crossover in this system.

  14. Charge density wave properties of the quasi two-dimensional purple molybdenum bronze KMo 6O 17

    Science.gov (United States)

    Balaska, H.; Dumas, J.; Guyot, H.; Mallet, P.; Marcus, J.; Schlenker, C.; Veuillen, J. Y.; Vignolles, D.

    2005-06-01

    The purple molybdenum bronze KMo 6O 17 is a quasi-two-dimensional compound which shows a Peierls transition towards a commensurate metallic CDW state. Electron spectroscopy (ARUPS), Scanning Tunnelling Microscopy (STM) and spectroscopy (STS) as well as high magnetic field studies are reported. ARUPS studies corroborate the model of the hidden nesting and provide a value of the CDW vector in good agreement with other measurements. STM studies visualize the triple- q CDW in real space. This is consistent with other measurements of the CDW vector. STS studies provide a value of several 10 meV for the average CDW gap. High magnetic field measurements performed in pulsed fields up to 55 T establish that first order transitions to smaller gap states take place at low temperature. These transitions are ascribed to Pauli type coupling. A phase diagram summarizing all observed anomalies and transitions is presented.

  15. Universal modeling of weak antilocalization corrections in quasi-two-dimensional electron systems using predetermined return orbitals

    Science.gov (United States)

    Sawada, A.; Koga, T.

    2017-02-01

    We have developed a method to calculate the weak localization and antilocalization corrections based on the real-space simulation, where we provide 147 885 predetermined return orbitals of quasi-two-dimensional electrons with up to 5000 scattering events that are repeatedly used. Our model subsumes that of Golub [L. E. Golub, Phys. Rev. B 71, 235310 (2005), 10.1103/PhysRevB.71.235310] when the Rashba spin-orbit interaction (SOI) is assumed. Our computation is very simple, fast, and versatile, where the numerical results, obtained all at once, cover wide ranges of the magnetic field under various one-electron interactions H' exactly. Thus, it has straightforward extensibility to incorporate interactions other than the Rashba SOI, such as the linear and cubic Dresselhaus SOIs, Zeeman effect, and even interactions relevant to the valley and pseudo spin degrees of freedom, which should provide a unique tool to study new classes of materials like emerging 2D materials. Using our computation, we also demonstrate the robustness of a persistent spin helix state against the cubic Dresselhaus SOI.

  16. Border-crossing model for the diffusive coarsening of two-dimensional and quasi-two-dimensional wet foams

    Science.gov (United States)

    Schimming, C. D.; Durian, D. J.

    2017-09-01

    For dry foams, the transport of gas from small high-pressure bubbles to large low-pressure bubbles is dominated by diffusion across the thin soap films separating neighboring bubbles. For wetter foams, the film areas become smaller as the Plateau borders and vertices inflate with liquid. So-called "border-blocking" models can explain some features of wet-foam coarsening based on the presumption that the inflated borders totally block the gas flux; however, this approximation dramatically fails in the wet or unjamming limit where the bubbles become close-packed spheres and coarsening proceeds even though there are no films. Here, we account for the ever-present border-crossing flux by a new length scale defined by the average gradient of gas concentration inside the borders. We compute that it is proportional to the geometric average of film and border thicknesses, and we verify this scaling by numerical solution of the diffusion equation. We similarly consider transport across inflated vertices and surface Plateau borders in quasi-two-dimensional foams. And we show how the d A /d t =K0(n -6 ) von Neumann law is modified by the appearance of terms that depend on bubble size and shape as well as the concentration gradient length scales. Finally, we use the modified von Neumann law to compute the growth rate of the average bubble area, which is not constant.

  17. Photon-exchange energy transfer of an electron–hole plasma between quasi-two-dimensional semiconductor layers

    International Nuclear Information System (INIS)

    Lyo, S.K.

    2012-01-01

    Photon-mediated energy transfer is shown to play an important role for transfer of an electron–hole plasma between two quasi-two-dimensional quantum wells separated by a wide barrier. The magnitude and the dependence of the transfer rate of an electron–hole plasma on the temperature, the well-to-well distance, and the plasma density are compared with those of the standard Förster (i.e., dipolar) rate and also with the exciton transfer rate. The plasma transfer rate through the photon-exchange mechanism decays very slowly as a function of the well-to-well distance and is larger than the dipolar rate except for short distances. The transfer rate of plasmas saturates at high densities and decays rapidly with the temperature. - Highlights: ► We study energy transfer (ET) between two two-dimensional semiconductor quantum wells. ► We compare the ET rates of an electron–hole plasma (at a high density) and Mott excitons. ► We show that the proposed photon-exchange rate is practically dominant over the Förster rate. ► We examine the dependences of the ET rate on the temperature, density, and well-to-well distance.

  18. Collective phenomena in a quasi-two-dimensional system of fermionic polar molecules: Band renormalization and excitons

    International Nuclear Information System (INIS)

    Babadi, Mehrtash; Demler, Eugene

    2011-01-01

    We theoretically analyze a quasi-two-dimensional system of fermionic polar molecules trapped in a harmonic transverse confining potential. The renormalized energy bands are calculated by solving the Hartree-Fock equation numerically for various trap and dipolar interaction strengths. The intersubband excitations of the system are studied in the conserving time-dependent Hartree-Fock (TDHF) approximation from the perspective of lattice modulation spectroscopy experiments. We find that the excitation spectrum consists of both intersubband particle-hole excitation continua and antibound excitons whose antibinding behavior is associated to the anisotropic nature of dipolar interactions. The excitonic modes are shown to capture the majority of the spectral weight. We evaluate the intersubband transition rates in order to investigate the nature of the excitonic modes and find that they are antibound states formed from particle-hole excitations arising from several subbands. We discuss the sum rules in the context of lattice modulation spectroscopy experiments and utilize them to check the consistency of the obtained results. Our results indicate that the excitonic effects persist for interaction strengths and temperatures accessible in the current experiments with polar molecules.

  19. Quasi-two-dimensional nonlinear evolution of helical magnetorotational instability in a magnetized Taylor-Couette flow

    Science.gov (United States)

    Mamatsashvili, G.; Stefani, F.; Guseva, A.; Avila, M.

    2018-01-01

    Magnetorotational instability (MRI) is one of the fundamental processes in astrophysics, driving angular momentum transport and mass accretion in a wide variety of cosmic objects. Despite much theoretical/numerical and experimental efforts over the last decades, its saturation mechanism and amplitude, which sets the angular momentum transport rate, remains not well understood, especially in the limit of high resistivity, or small magnetic Prandtl numbers typical to interiors (dead zones) of protoplanetary disks, liquid cores of planets and liquid metals in laboratory. Using direct numerical simulations, in this paper we investigate the nonlinear development and saturation properties of the helical magnetorotational instability (HMRI)—a relative of the standard MRI—in a magnetized Taylor-Couette flow at very low magnetic Prandtl number (correspondingly at low magnetic Reynolds number) relevant to liquid metals. For simplicity, the ratio of azimuthal field to axial field is kept fixed. From the linear theory of HMRI, it is known that the Elsasser number, or interaction parameter determines its growth rate and plays a special role in the dynamics. We show that this parameter is also important in the nonlinear problem. By increasing its value, a sudden transition from weakly nonlinear, where the system is slightly above the linear stability threshold, to strongly nonlinear, or turbulent regime occurs. We calculate the azimuthal and axial energy spectra corresponding to these two regimes and show that they differ qualitatively. Remarkably, the nonlinear state remains in all cases nearly axisymmetric suggesting that this HMRI-driven turbulence is quasi two-dimensional in nature. Although the contribution of non-axisymmetric modes increases moderately with the Elsasser number, their total energy remains much smaller than that of the axisymmetric ones.

  20. Quasi-two-dimensional turbulence in shallow fluid layers: the role of bottom friction and fluid layer depth.

    Science.gov (United States)

    Clercx, H J H; van Heijst, G J F; Zoeteweij, M L

    2003-06-01

    The role of bottom friction and the fluid layer depth in numerical simulations and experiments of freely decaying quasi-two-dimensional turbulence in shallow fluid layers has been investigated. In particular, the power-law behavior of the compensated kinetic energy E0(t)=E(t)e(2lambda t), with E(t) the total kinetic energy of the flow and lambda the bottom-drag coefficient, and the compensated enstrophy Omega(0)(t)=Omega(t)e(2lambda t), with Omega(t) the total enstrophy of the flow, have been studied. We also report on the scaling exponents of the ratio Omega(t)/E(t), which is considered as a measure of the characteristic length scale in the flow, for different values of lambda. The numerical simulations on square bounded domains with no-slip boundaries revealed bottom-friction independent power-law exponents for E0(t), Omega(0)(t), and Omega(t)/E(t). By applying a discrete wavelet packet transform technique to the numerical data, we have been able to compute the power-law exponents of the average number density of vortices rho(t), the average vortex radius a(t), the mean vortex separation r(t), and the averaged normalized vorticity extremum omega(ext)(t)/square root E(t). These decay exponents proved to be independent of the bottom friction as well. In the experiments we have varied the fluid layer depth, and it was found that the decay exponents of E0(t), Omega(0)(t), Omega(t)/E(t), and omega(ext)(t)/square root E(t) are virtually independent of the fluid layer depth. The experimental data for rho(t) and a(t) are less conclusive; power-law exponents obtained for small fluid layer depths agree with those from previously reported experiments, but significantly larger power-law exponents are found for experiments with larger fluid layer depths.

  1. Laserlike Vibrational Instability in Rectifying Molecular Conductors

    DEFF Research Database (Denmark)

    Lu, Jing Tao; Hedegård, Per; Brandbyge, Mads

    2011-01-01

    We study the damping of molecular vibrations due to electron-hole pair excitations in donor-acceptor (D-A) type molecular rectifiers. At finite voltage additional nonequilibrium electron-hole pair excitations involving both electrodes become possible, and contribute to the stimulated emission....... We investigate the effect in realistic molecular rectifier structures using first-principles calculations....

  2. High breakdown voltage quasi-two-dimensional β-Ga2O3 field-effect transistors with a boron nitride field plate

    Science.gov (United States)

    Bae, Jinho; Kim, Hyoung Woo; Kang, In Ho; Yang, Gwangseok; Kim, Jihyun

    2018-03-01

    We have demonstrated a β-Ga2O3 metal-semiconductor field-effect transistor (MESFET) with a high off-state breakdown voltage (344 V), based on a quasi-two-dimensional β-Ga2O3 field-plated with hexagonal boron nitride (h-BN). Both the β-Ga2O3 and h-BN were mechanically exfoliated from their respective crystal substrates, followed by dry-transfer onto a SiO2/Si substrate for integration into a high breakdown voltage quasi-two-dimensional β-Ga2O3 MESFETs. N-type conducting behavior was observed in the fabricated β-Ga2O3 MESFETs, along with a high on/off current ratio (>106) and excellent current saturation. A three-terminal off-state breakdown voltage of 344 V was obtained, with a threshold voltage of -7.3 V and a subthreshold swing of 84.6 mV/dec. The distribution of electric fields in the quasi-two-dimensional β-Ga2O3 MESFETs was simulated to analyze the role of the dielectric h-BN field plate in improving the off-state breakdown voltage. The stability of the field-plated β-Ga2O3 MESFET in air was confirmed after storing the MESFET in ambient air for one month. Our results pave the way for unlocking the full potential of β-Ga2O3 for use in a high-power nano-device with an ultrahigh breakdown voltage.

  3. Evidence for the quasi-two dimensional behavior of the vortex structure in Bi2Sr2CaCu2O8 single crystals

    International Nuclear Information System (INIS)

    Pastoriza, H.; Arribere, A.; Goffman, M.F.; Cruz, F. de la; Mitzi, D.B.; Kapitulnik, A.

    1994-01-01

    AC susceptibility and dc magnetization measurements on Bi 2 Sr 2 CaCu 2 O 8 (BSCCO) single crystals in a wide range of temperatures clearly show that below the dc irreversibility line the vortex system loss the long range order in the c direction. The susceptibility data taken at 7 Hz show the different nature of two dissipation peaks: One related to the interplane currents at temperatures well below the dc irreversibility line and the other associated with the intraplane ones at temperatures above that line. In this sense the irreversibility line corresponds to the temperature where quasi-two dimensional vortices are depinned. (orig.)

  4. Quasi-Two-Dimensional h-BN/β-Ga2O3 Heterostructure Metal-Insulator-Semiconductor Field-Effect Transistor.

    Science.gov (United States)

    Kim, Janghyuk; Mastro, Michael A; Tadjer, Marko J; Kim, Jihyun

    2017-06-28

    β-gallium oxide (β-Ga 2 O 3 ) and hexagonal boron nitride (h-BN) heterostructure-based quasi-two-dimensional metal-insulator-semiconductor field-effect transistors (MISFETs) were demonstrated by integrating mechanical exfoliation of (quasi)-two-dimensional materials with a dry transfer process, wherein nanothin flakes of β-Ga 2 O 3 and h-BN were utilized as the channel and gate dielectric, respectively, of the MISFET. The h-BN dielectric, which has an extraordinarily flat and clean surface, provides a minimal density of charged impurities on the interface between β-Ga 2 O 3 and h-BN, resulting in superior device performances (maximum transconductance, on/off ratio, subthreshold swing, and threshold voltage) compared to those of the conventional back-gated configurations. Also, double-gating of the fabricated device was demonstrated by biasing both top and bottom gates, achieving the modulation of the threshold voltage. This heterostructured wide-band-gap nanodevice shows a new route toward stable and high-power nanoelectronic devices.

  5. Angular studies of the magnetoresistance in the density wave state of the quasi-two-dimensional purple bronze KMo6O17

    Science.gov (United States)

    Guyot, H.; Dumas, J.; Kartsovnik, M. V.; Marcus, J.; Schlenker, C.; Sheikin, I.; Vignolles, D.

    2007-07-01

    The purple molybdenum bronze KMo6O17 is a quasi-two-dimensional compound which shows a Peierls transition towards a commensurate metallic charge density wave (CDW) state. High magnetic field measurements have revealed several transitions at low temperature and have provided an unusual phase diagram “temperature-magnetic field”. Angular studies of the interlayer magnetoresistance are now reported. The results suggest that the orbital coupling of the magnetic field to the CDW is the most likely mechanism for the field induced transitions. The angular dependence of the magnetoresistance is discussed on the basis of a warped quasi-cylindrical Fermi surface and provides information on the geometry of the Fermi surface in the low temperature density wave state.

  6. Quantum oscillations of thermomagnetic coefficients of layered conductors in a strong magnetic field

    International Nuclear Information System (INIS)

    Kirichenko, O.V.; Kozlov, I.V.; Peschansky, V.G.; Krstovska, D.

    2008-01-01

    The linear response of the electronic system of a conductor to a perturbation in the form of an electric field and a temperature gradient in a quantizing magnetic field B is investigated theoretically. The thermoelectric effect in a layered conductor is analyzed and it is shown that the quasi-two-dimensional character of the dispersion law of the charge carriers results in gigantic oscillations of the thermo-emf

  7. Electron and phonon drag in thermoelectric transport through coherent molecular conductors

    DEFF Research Database (Denmark)

    Lü, Jing-Tao; Wang, Jian-Sheng; Hedegård, Per

    2016-01-01

    We study thermoelectric transport through a coherent molecular conductor connected to two electron and two phonon baths using the nonequilibrium Green's function method. We focus on the mutual drag between electron and phonon transport as a result of ‘momentum’ transfer, which happens only when...

  8. Ionic Diffusion in a Ternary Superionic Conductor: An {ital Ab Initio} Molecular Dynamics Study

    Energy Technology Data Exchange (ETDEWEB)

    Wengert, S.; Nesper, R.; Andreoni, W.; Parrinello, M. [Laboratorium fuer Anorganische Chemie, ETH Zuerich, 8092 Zuerich (Switzerland)]|[IBM Research Division, Zurich Research Laboratory, 8803 Rueschlikon (Switzerland)]|[Max-Planck-Institut fuer Festkoerperforschung, 70569 Stuttgart (Germany)

    1996-12-01

    We present Car-Parrinello molecular dynamics simulations of a novel superionic conductor, Li{sub 2{minus}2{ital x}}Mg{sub 1+{ital x}}Si ({ital x}{approximately}0.06), at different temperatures. The calculations clarify the nature of the ionic conduction and lead to the prediction of the first inorganic magnesium superionic conductor. In fact, both lithium and magnesium are found to act as charge carriers. The diffusion is fast and can be described as vacancy migration through directed jumps. The calculated diffusion constants for lithium are consistent with recent electrochemical measurements. {copyright} {ital 1996 The American Physical Society.}

  9. Fingerprints of field-induced Berezinskii–Kosterlitz–Thouless transition in quasi-two-dimensional S=1/2 Heisenberg magnets Cu(en)(H2O)2SO4 and Cu(tn)Cl2

    International Nuclear Information System (INIS)

    Baranová, Lucia; Orendáčová, Alžbeta; Čižmár, Erik; Tarasenko, Róbert; Tkáč, Vladimír; Orendáč, Martin; Feher, Alexander

    2016-01-01

    Organo-metallic compounds Cu(en)(H 2 O) 2 SO 4 (en=C 2 H 8 N 2 ) and Cu(tn)Cl 2 (tn=C 3 H 10 N 2 ) representing S=1/2 quasi-two-dimensional Heisenberg antiferromagnets with an effective intra-layer exchange coupling J/k B ≈3 K, have been examined by specific heat measurements at temperatures down to nominally 50 mK and magnetic fields up to 14 T. A comparative analysis of magnetic specific heat in zero magnetic field revealed nearly identical contribution of short-range magnetic correlations and significant differences were observed at lowest temperatures. A phase transition to long-range order was observed in Cu(en)(H 2 O) 2 SO 4 at T C =0.9 K while hidden in Cu(tn)Cl 2 . A response of both compounds to the application of magnetic field has rather universal features characteristic for a field-induced Berezinskii–Kosterlitz–Thouless transition theoretically predicted for ideal two-dimensional magnets. - Highlights: • Magnetic specific heat of Cu(en)(H 2 O) 2 SO 4 (1) and Cu(tn)Cl 2 (2) was analysed. • In zero magnetic field, (1) and (2) behave as quasi-two-dimensional magnets. • We observed universal thermodynamic response of (1) and (2) to applied field. • Features of field-induced Berezinskii–Kosterlitz–Thouless transition were detected.

  10. Evidence for the quasi-two dimensional behavior of the vortex structure in Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8] single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Pastoriza, H [Comision Nacional de Energia Atomica, Centro Atomico Bariloche (Argentina); Arribere, A [Comision Nacional de Energia Atomica, Centro Atomico Bariloche (Argentina); Goffman, M F [Comision Nacional de Energia Atomica, Centro Atomico Bariloche (Argentina); Cruz, F de la [Comision Nacional de Energia Atomica, Centro Atomico Bariloche (Argentina); Mitzi, D B [Dept. of Applied Physics, Stanford Univ., CA (United States); Kapitulnik, A [Dept. of Applied Physics, Stanford Univ., CA (United States)

    1994-02-01

    AC susceptibility and dc magnetization measurements on Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8] (BSCCO) single crystals in a wide range of temperatures clearly show that below the dc irreversibility line the vortex system loss the long range order in the c direction. The susceptibility data taken at 7 Hz show the different nature of two dissipation peaks: One related to the interplane currents at temperatures well below the dc irreversibility line and the other associated with the intraplane ones at temperatures above that line. In this sense the irreversibility line corresponds to the temperature where quasi-two dimensional vortices are depinned. (orig.)

  11. Quasi-two-dimensional electron gas at the epitaxial alumina/SrTiO{sub 3} interface: Control of oxygen vacancies

    Energy Technology Data Exchange (ETDEWEB)

    Kormondy, Kristy J.; Posadas, Agham B.; Demkov, Alexander A., E-mail: demkov@physics.utexas.edu [Department of Physics, University of Texas at Austin, Austin, Texas 78712 (United States); Ngo, Thong Q.; Ekerdt, John G. [Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712 (United States); Lu, Sirong; Smith, David J.; McCartney, Martha R. [Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States); Goble, Nicholas; Gao, Xuan P. A. [Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106 (United States); Jordan-Sweet, Jean [IBM T.J. Watson Research Center, Yorktown Heights, New York 10598 (United States)

    2015-03-07

    In this paper, we report on the highly conductive layer formed at the crystalline γ-alumina/SrTiO{sub 3} interface, which is attributed to oxygen vacancies. We describe the structure of thin γ-alumina layers deposited by molecular beam epitaxy on SrTiO{sub 3} (001) at growth temperatures in the range of 400–800 °C, as determined by reflection-high-energy electron diffraction, x-ray diffraction, and high-resolution electron microscopy. In situ x-ray photoelectron spectroscopy was used to confirm the presence of the oxygen-deficient layer. Electrical characterization indicates sheet carrier densities of ∼10{sup 13 }cm{sup −2} at room temperature for the sample deposited at 700 °C, with a maximum electron Hall mobility of 3100 cm{sup 2}V{sup −1}s{sup −1} at 3.2 K and room temperature mobility of 22 cm{sup 2}V{sup −1}s{sup −1}. Annealing in oxygen is found to reduce the carrier density and turn a conductive sample into an insulator.

  12. Effects of electron-phonon interaction on thermal and electrical transport through molecular nano-conductors

    Energy Technology Data Exchange (ETDEWEB)

    Lü, Jing-Tao, E-mail: jtlu@hust.edu.cn [School of Physics, Huazhong University of Science and Technology, 430074 Wuhan (China); Zhou, Hangbo [Department of Physics and Center for Computational Science and Engineering, National University of Singapore, 117551 Singapore (Singapore); NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 117456 Singapore (Singapore); Jiang, Jin-Wu [Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, 200072 Shanghai (China); Wang, Jian-Sheng [Department of Physics and Center for Computational Science and Engineering, National University of Singapore, 117551 Singapore (Singapore)

    2015-05-15

    The topic of this review is the effects of electron-phonon interaction (EPI) on the transport properties of molecular nano-conductors. A nano-conductor connects to two electron leads and two phonon leads, possibly at different temperatures or chemical potentials. The EPI appears only in the nano-conductor. We focus on its effects on charge and energy transport. We introduce three approaches. For weak EPI, we use the nonequilibrium Green’s function method to treat it perturbatively. We derive the expressions for the charge and heat currents. For weak system-lead couplings, we use the quantum master equation approach. In both cases, we use a simple single level model to study the effects of EPI on the system’s thermoelectric transport properties. It is also interesting to look at the effect of currents on the dynamics of the phonon system. For this, we derive a semi-classical generalized Langevin equation to describe the nano-conductor’s atomic dynamics, taking the nonequilibrium electron system, as well as the rest of the atomic degrees of freedom as effective baths. We show simple applications of this approach to the problem of energy transfer between electrons and phonons.

  13. Effects of electron-phonon interaction on thermal and electrical transport through molecular nano-conductors

    International Nuclear Information System (INIS)

    Lü, Jing-Tao; Zhou, Hangbo; Jiang, Jin-Wu; Wang, Jian-Sheng

    2015-01-01

    The topic of this review is the effects of electron-phonon interaction (EPI) on the transport properties of molecular nano-conductors. A nano-conductor connects to two electron leads and two phonon leads, possibly at different temperatures or chemical potentials. The EPI appears only in the nano-conductor. We focus on its effects on charge and energy transport. We introduce three approaches. For weak EPI, we use the nonequilibrium Green’s function method to treat it perturbatively. We derive the expressions for the charge and heat currents. For weak system-lead couplings, we use the quantum master equation approach. In both cases, we use a simple single level model to study the effects of EPI on the system’s thermoelectric transport properties. It is also interesting to look at the effect of currents on the dynamics of the phonon system. For this, we derive a semi-classical generalized Langevin equation to describe the nano-conductor’s atomic dynamics, taking the nonequilibrium electron system, as well as the rest of the atomic degrees of freedom as effective baths. We show simple applications of this approach to the problem of energy transfer between electrons and phonons

  14. Soft X-ray photoemission study of organic conductors BEDT-TTF and BEDO-TTF salts

    International Nuclear Information System (INIS)

    Tsunekawa, M.; Sekiyama, A.; Imada, S.; Saita, T.; Maesato, M.; Yamochi, H.; Saito, G.; Suga, S.

    2005-01-01

    We have performed a soft X-ray photoemission (PES) study of quasi-two-dimensional organic conductors BEDT-TTF (ET) and BEDO-TTF (BO) salts. We have clarified the difference in the electronic states between the bulk and surface insulating layers. The difference of the electronic states between ET and BO molecules is also found. On the other hand, the spectral weight in the vicinity of Fermi level is suppressed as reported by the low-energy PES

  15. Quasi-two-dimensional electron gas at the interface of γ-Al{sub 2}O{sub 3}/SrTiO{sub 3} heterostructures grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ngo, Thong Q.; McDaniel, Martin D.; Ekerdt, John G., E-mail: ekerdt@che.utexas.edu [Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712 (United States); Goble, Nicholas J.; Gao, Xuan P. A. [Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106 (United States); Posadas, Agham; Kormondy, Kristy J.; Demkov, Alexander A. [Department of Physics, University of Texas at Austin, Austin, Texas 78712 (United States); Lu, Sirong [School of Engineering for Matter, Transport and Engineering, Arizona State University, Tempe, Arizona 85287 (United States); Jordan-Sweet, Jean [IBM T.J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Smith, David J. [Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States)

    2015-09-21

    We report the formation of a quasi-two-dimensional electron gas (2-DEG) at the interface of γ-Al{sub 2}O{sub 3}/TiO{sub 2}-terminated SrTiO{sub 3} (STO) grown by atomic layer deposition (ALD). The ALD growth of Al{sub 2}O{sub 3} on STO(001) single crystal substrates was performed at temperatures in the range of 200–345 °C. Trimethylaluminum and water were used as co-reactants. In situ reflection high energy electron diffraction, ex situ x-ray diffraction, and ex situ cross-sectional transmission electron microscopy were used to determine the crystallinity of the Al{sub 2}O{sub 3} films. As-deposited Al{sub 2}O{sub 3} films grown above 300 °C were crystalline with the γ-Al{sub 2}O{sub 3} phase. In situ x-ray photoelectron spectroscopy was used to characterize the Al{sub 2}O{sub 3}/STO interface, indicating that a Ti{sup 3+} feature in the Ti 2p spectrum of STO was formed after 2–3 ALD cycles of Al{sub 2}O{sub 3} at 345 °C and even after the exposure to trimethylaluminum alone at 300 and 345 °C. The interface quasi-2-DEG is metallic and exhibits mobility values of ∼4 and 3000 cm{sup 2} V{sup −1} s{sup −1} at room temperature and 15 K, respectively. The interfacial conductivity depended on the thickness of the Al{sub 2}O{sub 3} layer. The Ti{sup 3+} signal originated from the near-interfacial region and vanished after annealing in an oxygen environment.

  16. Film-based Sensors with Piezoresistive Molecular Conductors as Active Components Strain Damage and Thermal Regeneration

    Directory of Open Access Journals (Sweden)

    Elena Laukhina

    2011-02-01

    Full Text Available The article is addressed to the development of flexible all-organic bi layer (BL film-based sensors being capable of measuring strain as a well-defined electrical signal in a wide range of elongations and temperature. The purpose was achieved by covering polycarbonate films with the polycrystalline layer of a high piezoresistive organic molecular conductor. To determine restrictions for sensor applications, the effect of monoaxial strain on the resistance and texture of the sensing layers of BL films was studied. The experiments have shown that the maximum strain before fracture is about 1 %. A thermal regeneration of the sensing layer of the BL film-based sensors that were damaged by cyclic load is also described. These sensors are able to take the place of conventional metal-based strain and pressure gages in low cost innovative controlling and monitoring technologies.

  17. Attractive mechanical properties of a lightweight highly sensitive bi layer thermistor: polycarbonate/organic molecular conductor

    International Nuclear Information System (INIS)

    Laukhina, E; Lebedev, V; Rovira, C; Laukhin, V; Veciana, J

    2016-01-01

    The paper covers some of the basic mechanical characteristics of a recently developed bi layer thermistor: polycarbonate/(001) oriented layer of organic molecular conductor α’-(BEDT-TTF) 2 I x Br 3-x , were BEDT-TTF=bis(ethylenedithio)tetrathiafulvalen. The nano and macro mechanical properties have been studied in order to use this flexible, low cost thermistor in sensing applications by proper way. The nano-mechanical properties of the temperature sensitive semiconducting layer of α’-(BEDT-TTF) 2 I x Br 3-x were tested using nanoindentation method. The value of Young's modulus in direction being perpendicular to the layer plan was found as 9.0 ±1.4 GPa. The macro mechanical properties of the thermistor were studied using a 5848 MicroTester. The tensile tests showed that basic mechanical characteristics of the thermistor are close to those of polycarbonate films. This indicates a good mechanical strength of the developed sensor. Therefore, the thermistor can be used in technologies that need to be instrumented with highly robustness lightweight low cost temperature sensors. The paper also reports synthetic details on fabricating temperature sensing e-textile. As the temperature control is becoming more and more important in biomedical technologies like healthcare monitoring, this work strongly contributes on the ongoing research on engineering sensitive conducting materials for biomedical applications. (paper)

  18. Fingerprints of field-induced Berezinskii–Kosterlitz–Thouless transition in quasi-two-dimensional S=1/2 Heisenberg magnets Cu(en)(H{sub 2}O){sub 2}SO{sub 4} and Cu(tn)Cl{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Baranová, Lucia [Civil Engineering Faculty, Department of Applied Mathematics, Technical University of Košice, Vysokoškolská 4 SK-042 00, Košice (Slovakia); Orendáčová, Alžbeta, E-mail: alzbeta.orendacova@upjs.sk [Center of Low Temperature Physics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9 SK-041 54, Košice (Slovakia); Čižmár, Erik [Center of Low Temperature Physics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9 SK-041 54, Košice (Slovakia); Tarasenko, Róbert; Tkáč, Vladimír [Center of Low Temperature Physics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9 SK-041 54, Košice (Slovakia); Charles University, Faculty of Mathematics and Physics, Ke Karlovu 5 12116, Prague (Czech Republic); Orendáč, Martin; Feher, Alexander [Center of Low Temperature Physics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9 SK-041 54, Košice (Slovakia)

    2016-04-15

    Organo-metallic compounds Cu(en)(H{sub 2}O){sub 2}SO{sub 4} (en=C{sub 2}H{sub 8}N{sub 2}) and Cu(tn)Cl{sub 2} (tn=C{sub 3}H{sub 10}N{sub 2}) representing S=1/2 quasi-two-dimensional Heisenberg antiferromagnets with an effective intra-layer exchange coupling J/k{sub B}≈3 K, have been examined by specific heat measurements at temperatures down to nominally 50 mK and magnetic fields up to 14 T. A comparative analysis of magnetic specific heat in zero magnetic field revealed nearly identical contribution of short-range magnetic correlations and significant differences were observed at lowest temperatures. A phase transition to long-range order was observed in Cu(en)(H{sub 2}O){sub 2}SO{sub 4} at T{sub C}=0.9 K while hidden in Cu(tn)Cl{sub 2}. A response of both compounds to the application of magnetic field has rather universal features characteristic for a field-induced Berezinskii–Kosterlitz–Thouless transition theoretically predicted for ideal two-dimensional magnets. - Highlights: • Magnetic specific heat of Cu(en)(H{sub 2}O){sub 2}SO{sub 4} (1) and Cu(tn)Cl{sub 2} (2) was analysed. • In zero magnetic field, (1) and (2) behave as quasi-two-dimensional magnets. • We observed universal thermodynamic response of (1) and (2) to applied field. • Features of field-induced Berezinskii–Kosterlitz–Thouless transition were detected.

  19. Blowing the Fuse: Berry's Phase and Runaway Vibrations in Molecular Conductors

    DEFF Research Database (Denmark)

    Lu, Jing Tao; Brandbyge, Mads; Hedegård, P.

    2010-01-01

    We examine a molecular bridge connecting two metallic electrodes. We find that an electronic current passing across the bridge can cause a vibrational instability of the molecule, which ultimately can lead to a breakdown of the bridge. This instability is generated by a hitherto never considered ...

  20. Synthesis of Ruthenium(III Phthalocyanine with Di-axial Bromo Ligands - A Promising Molecular Conductor with Giant Negative Magnetoresistance

    Directory of Open Access Journals (Sweden)

    Mario A.V. Gamboa

    2015-01-01

    Full Text Available The electron transport of Phthalocyanines (Pc with central metal and di-axial ligands (such as FeIII(PcL2; where L = CN, Cl, Br originates from its intermolecular Pc π-π orbital overlap while its giant negative magnetoresistance (GNMR arises from its intramolecular Pc-π(HOMO and Fe-d (s=1/2 interaction. However, the π-d interaction tends to localize itinerant electrons resulting in the decrease in the conductivity of the FeIII(PcL2 series compared to the non-magnetic CoIII(PcL2 where π-d interaction is absent. More so, the axial ligand field energy of the FeIII(PcL2 system is found to have the ability to proportionally modulate the π-d interaction. In reference thereof, theoretical calculations point that isostructural RuIII(PcBr2 would provide the best balance of π-d orbital energy interplay. That is, RuIII(PcBr2 is expected to be a molecule with high electrical conductivity and GNMR which would make it an ideal magnetic molecular conductor. This paper reports on the synthesis of RuIII(PcBr2.

  1. Correlated particle dynamics in concentrated quasi-two-dimensional suspensions

    International Nuclear Information System (INIS)

    Diamant, H; Cui, B; Lin, B; Rice, S A

    2005-01-01

    We investigate theoretically and experimentally how the hydrodynamically correlated lateral motion of particles in a suspension confined between two surfaces is affected by the suspension concentration. Despite the long range of the correlations (decaying as 1/r 2 with the inter-particle distance r), the concentration effect is present only at short inter-particle distances for which the static pair correlation is nonuniform. This is in sharp contrast with the effect of hydrodynamic screening in unconfined suspensions, where increasing the concentration changes the prefactor of the large-distance correlation

  2. Uncovering a new quasi-2D CuO2 plane between the YBa2Cu3O7 and CeO2 buffer layer of coated conductors

    Science.gov (United States)

    Li, Zhi-Xin; Cao, Jin-Jin; Gou, Xiao-Fan; Wang, Tian-Ge; Xue, Feng

    2018-01-01

    We report a discovery of the quasi-two-dimensional (quasi-2D) CuO2 plane between the superconductor YBa2Cu3O7 (YBCO) and CeO2 buffer layer (mostly used in the fabrication) of coated conductors through the atomistic computer simulations with the molecular dynamics (MD) and first-principle calculations. For an YBCO coated conductor with multilayer structures, the buffer layers deposited onto a substrate are mainly considered to transfer a strong biaxial texture from the substrate to the YBCO layer. To deeply understand the tuning mechanism of the texture transfer, exploring the complete atomic-level picture of the structure between the YBa2Cu3O7/CeO2 interfaces is firstly required. However, the related observation data have not been available due to some big challenges of experimental techniques. With the MD simulations, having tested the accuracy of the potential functions for the YBa2Cu3O7/CeO2 interface, we constructed a total of 54 possible atom stacking models of the interface and identified its most appropriate and stable structure according to the criterion of the interface adhesion energy and the coherent characterization. To further verify the stability of the identified structure, we performed the first-principle calculations to obtain the adhesion energy and developed the general knowledge of the interface structure. Finally, a coherent interface formed with a new built quasi-2D CuO2 plane that is structurally similar to the CuO2 plane inside bulk YBCO was determined.

  3. New aspects of π–d interactions in magnetic molecular conductors

    Science.gov (United States)

    Sugimoto, Toyonari; Fujiwara, Hideki; Noguchi, Satoru; Murata, Keizo

    2009-01-01

    The 2 : 1 cation radical salts of bent donor molecules of ethylenedithio-tetrathiafulvalenoquinone-1,3-dithiolemethide (EDT-TTFVO), ethylenedithio-diselenadithiafulvalenoquinone-1,3-dithiolemethide (EDT-DSDTFVO), ethylenedithio-diselenadithiafulvalenothioquinone-1,3-diselenolemethide (EDT-DSDTFVSDS), ethylenedioxy-tetrathiafulvalenoquinone-1,3-dithiolemethide (EDO-TTFVO) and ethylenedioxy-tetrathiafulvalenoquinone-1,3-diselenolemethide (EDO-TTFVODS) with FeX4− (X = Cl, Br) ions are prepared by electrocrystallization. The crystal structures of these salts are composed of alternately stacked donor molecule and magnetic anion layers. The band structures of the donor molecule layers are calculated using the overlap integrals between neighboring donor molecules and are compared with the observed electronic transport properties. The magnetic ordering of the Fe(III) d spins of FeX4− ions is determined from magnetization and heat capacity measurements. The magnetic ordering temperatures are estimated by considering a combination of a direct d–d interaction between the d spins and an indirect π–d interaction between the conduction π electron and the d spins, whose magnitudes are separately calculated from the crystal structures with an extended Hückel molecular orbital method. The occurrence of a π–d interaction is proved by the negative magnetoresistance, and the magnitude of magnetoresistance reflects the strength of the π–d interaction. The effect of pressure on the magnetoresistance is studied, and the result indicates that the magnitude of magnetoresistance increases, namely, the π–d interaction is enhanced with increasing pressure. From these experimental results it is shown that (EDT-TTFVO)2•FeBr4 is a ferromagnetic semiconductor, (EDT-DSDTFVO)2•FeX4 (X = Cl, Br) and (EDT-DSDTFVSDS)2•FeBr4 are metals exhibiting antiferromagnetic ordering of the d spins, and (EDO-TTFVO)2•FeCl4 and (EDO-TTFVODS)2•FeBr4•(DCE)0.5 (DCE =-dichloroethane) are

  4. TOPICAL REVIEW: New aspects of π-d interactions in magnetic molecular conductors

    Science.gov (United States)

    Sugimoto, Toyonari; Fujiwara, Hideki; Noguchi, Satoru; Murata, Keizo

    2009-04-01

    The 2 : 1 cation radical salts of bent donor molecules of ethylenedithio-tetrathiafulvalenoquinone-1,3-dithiolemethide (EDT-TTFVO), ethylenedithio-diselenadithiafulvalenoquinone-1,3-dithiolemethide (EDT-DSDTFVO), ethylenedithio-diselenadithiafulvalenothioquinone-1,3-diselenolemethide (EDT-DSDTFVSDS), ethylenedioxy-tetrathiafulvalenoquinone-1,3-dithiolemethide (EDO-TTFVO) and ethylenedioxy-tetrathiafulvalenoquinone-1,3-diselenolemethide (EDO-TTFVODS) with FeX4- (X = Cl, Br) ions are prepared by electrocrystallization. The crystal structures of these salts are composed of alternately stacked donor molecule and magnetic anion layers. The band structures of the donor molecule layers are calculated using the overlap integrals between neighboring donor molecules and are compared with the observed electronic transport properties. The magnetic ordering of the Fe(III) d spins of FeX4- ions is determined from magnetization and heat capacity measurements. The magnetic ordering temperatures are estimated by considering a combination of a direct d-d interaction between the d spins and an indirect π-d interaction between the conduction π electron and the d spins, whose magnitudes are separately calculated from the crystal structures with an extended Hückel molecular orbital method. The occurrence of a π-d interaction is proved by the negative magnetoresistance, and the magnitude of magnetoresistance reflects the strength of the π-d interaction. The effect of pressure on the magnetoresistance is studied, and the result indicates that the magnitude of magnetoresistance increases, namely, the π-d interaction is enhanced with increasing pressure. From these experimental results it is shown that (EDT-TTFVO)2•FeBr4 is a ferromagnetic semiconductor, (EDT-DSDTFVO)2•FeX4 (X = Cl, Br) and (EDT-DSDTFVSDS)2•FeBr4 are metals exhibiting antiferromagnetic ordering of the d spins, and (EDO-TTFVO)2•FeCl4 and (EDO-TTFVODS)2•FeBr4•(DCE)0.5 (DCE =-dichloroethane) are genuine

  5. Focus on Organic Conductors

    Directory of Open Access Journals (Sweden)

    Shinya Uji, Takehiko Mori and Toshihiro Takahashi

    2009-01-01

    Full Text Available Organic materials are usually thought of as electrical insulators. Progress in chemical synthesis, however, has brought us a rich variety of conducting organic materials, which can be classified into conducting polymers and molecular crystals. Researchers can realize highly conducting molecular crystals in charge-transfer complexes, where suitable combinations of organic electron donor or acceptor molecules with counter ions or other organic molecules provide charge carriers. By means of a kind of chemical doping, the charge-transfer complexes exhibit high electrical conductivity and, thanks to their highly crystalline nature, even superconductivity has been observed. This focus issue of Science and Technology of Advanced Materials is devoted to the research into such 'organic conductors'The first organic metal was (TTF(TCNQ, which was found in 1973 to have high conductivity at room temperature and a metal–insulator transition at low temperatures. The first organic superconductor was (TMTSF2PF6, whose superconductivity under high pressures was reported by J´erome in 1980. After these findings, the research on organic conductors exploded. Hundreds of organic conductors have been reported, among which more than one hundred exhibit superconductivity. Recently, a single-component organic conductor has been found with metallic conductivity down to low temperatures.In these organic conductors, in spite of their simple electronic structures, much new physics has arisen from the low dimensionality. Examples are charge and spin density waves, characteristic metal–insulator transitions, charge order, unconventional superconductivity, superconductor–insulator transitions, and zero-gap conductors with Dirac cones. The discovery of this new physics is undoubtedly derived from the development of many intriguing novel organic conductors. High quality single crystals are indispensable to the precise measurement of electronic states.This focus issue

  6. Model construction and superconductivity analysis of organic conductors β-(BDA-TTP)2MF6 (M = P, As, Sb and Ta) based on first-principles band calculation

    Science.gov (United States)

    Aizawa, H.; Kuroki, K.; Yasuzuka, S.; Yamada, J.

    2012-11-01

    We perform a first-principles band calculation for a group of quasi-two-dimensional organic conductors β-(BDA-TTP)2MF6 (M = P, As, Sb and Ta). The ab-initio calculation shows that the density of states is correlated with the bandwidth of the singly occupied (highest) molecular orbital, while it is not necessarily correlated with the unit-cell volume. The direction of the major axis of the cross section of the Fermi surface lies in the Γ-B-direction, which differs from that obtained by the extended Hückel calculation. Then, we construct a tight-binding model which accurately reproduces the ab-initio band structure. The obtained transfer energies give a smaller dimerization than in the extended Hückel band. As to the difference in the anisotropy of the Fermi surface, the transfer energies along the inter-stacking direction are smaller than those obtained in the extended Hückel calculation. Assuming spin-fluctuation-mediated superconductivity, we apply random phase approximation to a two-band Hubbard model. This two-band Hubbard model is composed of the tight-binding model derived from the first-principles band structure and an on-site (intra-molecule) repulsive interaction taken as a variable parameter. The obtained superconducting gap changes sign four times along the Fermi surface like in a d-wave gap, and the nodal direction is different from that obtained in the extended Hückel model. Anion dependence of Tc is qualitatively consistent with the experimental observation.

  7. Model construction and superconductivity analysis of organic conductors β-(BDA-TTP)2MF6 (M = P, As, Sb and Ta) based on first-principles band calculation

    International Nuclear Information System (INIS)

    Aizawa, H; Kuroki, K; Yasuzuka, S; Yamada, J

    2012-01-01

    We perform a first-principles band calculation for a group of quasi-two-dimensional organic conductors β-(BDA-TTP) 2 MF 6 (M = P, As, Sb and Ta). The ab-initio calculation shows that the density of states is correlated with the bandwidth of the singly occupied (highest) molecular orbital, while it is not necessarily correlated with the unit-cell volume. The direction of the major axis of the cross section of the Fermi surface lies in the Γ–B-direction, which differs from that obtained by the extended Hückel calculation. Then, we construct a tight-binding model which accurately reproduces the ab-initio band structure. The obtained transfer energies give a smaller dimerization than in the extended Hückel band. As to the difference in the anisotropy of the Fermi surface, the transfer energies along the inter-stacking direction are smaller than those obtained in the extended Hückel calculation. Assuming spin-fluctuation-mediated superconductivity, we apply random phase approximation to a two-band Hubbard model. This two-band Hubbard model is composed of the tight-binding model derived from the first-principles band structure and an on-site (intra-molecule) repulsive interaction taken as a variable parameter. The obtained superconducting gap changes sign four times along the Fermi surface like in a d-wave gap, and the nodal direction is different from that obtained in the extended Hückel model. Anion dependence of T c is qualitatively consistent with the experimental observation. (paper)

  8. Theoretical study of the zero-gap organic conductor α-(BEDT-TTF2I3

    Directory of Open Access Journals (Sweden)

    Akito Kobayashi, Shinya Katayama and Yoshikazu Suzumura

    2009-01-01

    Full Text Available The quasi-two-dimensional molecular conductor α-(BEDT-TTF2I3 exhibits anomalous transport phenomena where the temperature dependence of resistivity is weak but the ratio of the Hall coefficient at 10 K to that at room temperature is of the order of 104. These puzzling phenomena were solved by predicting massless Dirac fermions, whose motions are described using the tilted Weyl equation with anisotropic velocity. α-(BEDT-TTF2I3 is a unique material among several materials with Dirac fermions, i.e. graphene, bismuth, and quantum wells such as HgTe, from the view-points of both the structure and electronic states described as follows. α-(BEDT-TTF2I3 has the layered structure with highly two-dimensional massless Dirac fermions. The anisotropic velocity and incommensurate momenta of the contact points, ±k0, originate from the inequivalency of the BEDT-TTF sites in the unit cell, where ±k0 moves in the first Brillouin zone with increasing pressure. The massless Dirac fermions exist in the presence of the charge disproportionation and are robust against the increase in pressure. The electron densities on those inequivalent BEDT-TTF sites exhibit anomalous momentum distributions, reflecting the angular dependences of the wave functions around the contact points. Those unique electronic properties affect the spatial oscillations of the electron densities in the vicinity of an impurity. A marked behavior of the Hall coefficient, where the sign of the Hall coefficient reverses sharply but continuously at low temperatures around 5 K, is investigated by treating the interband effects of the magnetic field exactly. It is shown that such behavior is possible by assuming the existence of the extremely small amount of electron doping. The enhancement of the orbital diamagnetism is also expected. The results of the present research shed light on a new aspect of Dirac fermion physics, i.e. the emergence of unique electronic properties owing to the structure

  9. Conductores recubiertos

    Directory of Open Access Journals (Sweden)

    P. Garcés

    2008-07-01

    Full Text Available Since the 1960s, Nb–Ti, exhibiting a superconducting transition temperature Tc of 9K, and Nb3Sn, with a Tc of 18K have been the materials of choice for superconducting applications. The prospects for the future changed dramatically with the discovery of ceramic high temperature superconductors exhibiting Tc values well above the boiling temperature of liquid nitrogen (77K. These materials are now widely considered for large power applications, electronics and magnets as in microelectronics. The first case corresponding power transmission wires, motors, generators, fault current limiters, transformers, etc. and technology related small scale manufacturing SQUID superconductors. Nevertheless, the fabrication of useful conductors out of these layered cuprates encountered some problems such as chemical and structural purity, stability, oxygen stoichiometric and weak links limiting current carrying capacity. However, despite these difficulties a first generation of silver sheathed composites based on (Bi,PbSrCaCuO (solving the problem of inherent fragility of these materials has already been commercialized. It is now a widespread view that superconducting wires with high performance under strong magnetic fields and at elevated temperatures above liquid nitrogen, will need to be realized using the (REBaCuO (RE = rare earth materials. Chemical deposition techniques (CVD of thick films, appear as the most suitable for this purpose, so the study of various chemical deposition techniques that allow to grow superconducting films and buffer layers with the right texture to produce a coated conductor Proper alignment and high current carrying capacity (∼ 1 MA/cm2 are now booming.

  10. Magneto-optical studies of low-dimensional organic conductors

    Directory of Open Access Journals (Sweden)

    Hitoshi Ohta, Motoi Kimata and Yugo Oshima

    2009-01-01

    Full Text Available Our periodic orbit resonance (POR results on quasi-two-dimensional (q2D, highly anisotropic q2D and quasi-one-dimensional (q1D organic conductors are reviewed together with our rotational cavity magneto-optical measurement system. Higher order POR up to seventh order has been observed in the q2D system (BEDT-TTF2Br(DIA, and the experimental conditions to observe POR and the cyclotron resonance (CR are discussed. Highly anisotropic q2D Fermi surface (FS in β''-(BEDT-TTF(TCNQ, which was considered to have q1D FS previously, is proposed by our POR measurements, and the possible interpretations of other experimental results of β''-(BEDT-TTF(TCNQ are discussed assuming the highly anisotropic q2D FS. Finally, detailed q1D FS of (DMET2I3, obtained from our POR results, is discussed in connection with the typical q1D system (TMTSF2ClO4.

  11. Extensive Evaluation of the Conductor-like Screening Model for Real Solvents Method in Predicting Liquid-Liquid Equilibria in Ternary Systems of Ionic Liquids with Molecular Compounds.

    Science.gov (United States)

    Paduszyński, Kamil

    2018-04-12

    A conductor-like screening model for real solvents (COSMO-RS) is nowadays one of the most popular and commonly applied tools for the estimation of thermodynamic properties of complex fluids. The goal of this work is to provide a comprehensive review and analysis of the performance of this approach in calculating liquid-liquid equilibrium (LLE) phase diagrams in ternary systems composed of ionic liquid and two molecular compounds belonging to diverse families of chemicals (alkanes, aromatics, S/N-compounds, alcohols, ketones, ethers, carboxylic acid, esters, and water). The predictions are presented for extensive experimental database, including 930 LLE data sets and more than 9000 data points (LLE tie lines) reported for 779 unique ternary mixtures. An impact of the type of molecular binary subsystem on the accuracy of predictions is demonstrated and discussed on the basis of representative examples. The model's capability of capturing qualitative trends in the LLE distribution ratio and selectivity is also checked for a number of structural effects. Comparative analysis of two levels of quantum chemical theory (BP-TZVP-COSMO vs BP-TZVPD-FINE) for the input molecular data for COSMO-RS is presented. Finally, some general recommendations for the applicability of the model are indicated based on the analysis of the global performance as well as on the results obtained for systems relevant from the point of view of important separation problems.

  12. A “Swingable” straight-chain affinity molecule immobilized on a semi-conductor electrode for photo-excited current-based molecular sensing

    International Nuclear Information System (INIS)

    Takatsuji, Yoshiyuki; Wakabayashi, Ryo; Sakakura, Tatsuya; Haruyama, Tetsuya

    2015-01-01

    The molecular affinities of biomolecules have found applications in the areas of clinical diagnostics, drug discovery, as well as allied fields of study. An affinity sensor is a unique in situ assay tool, which is valuable and convenient in practical situations. In this study, we designed a photo-excitable molecular interface with an affinity domain and fabricated with a “swingable” straight-chain affinity molecule immobilized on a semi-conductor electrode (SCE). The straight-chain affinity molecule possessed a photo-excitable dye at one end and was bound to the SCE surface at the other by the EC tag method, which was developed previously. A straight-chain molecule is too long to transfer electrons from the photo-excited dye to the conduction band of the SCE. However, the straight-chain molecule was designed with a “swing” structure, which made the transfer of electrons possible. The central region of the chain molecule has an affinity to the activated estrogen receptor (ER). When the activated ER bound to the affinity region, the molecular lost its swingable function, the electron transfer from the photo-excited dye to the SCE was consequently suppressed. Based on the unique swingable molecular interface, the affinity sensor can be used to determine the in situ concentration of endocrine disrupter ESTROGEN (17β-estradiol) at concentrations ranging from 2 to 10 nM with very good reproducibility. The superior assay reproducibility is responsible for the success of the EC tag method, which is a quantitative method for immobilizing molecules on SCE.

  13. Magnetic-breakdown oscillations of the thermoelectric field in layered conductors

    Energy Technology Data Exchange (ETDEWEB)

    Peschanskii, V. G., E-mail: vpeschansky@ilt.kharkov.ua [Karazin Kharkov National University (Ukraine); Galbova, O. [St. Cyril and Methodium University (Macedonia, The Former Yugoslav Republic of); Hasan, R. [Karazin Kharkov National University (Ukraine)

    2016-12-15

    The response of an electron system to nonuniform heating of layered conductors with an arbitrary quasi-two-dimensional electron energy spectrum in a strong magnetic field B is investigated theoretically in the case when cyclotron frequency ω{sub c} is much higher than the frequency 1/τ of collisions between charge carriers. In the case of a multisheet Fermi surface (FS), we calculate the dependence of the thermoelectric coefficients on the magnitude and orientation of the magnetic field in the vicinity of the Lifshitz topological transition when the FS connectivity changes under the action of an external force (e.g., pressure) on the conductor. Upon a decrease in the spacing between individual pockets (sheets) of the FS, conduction electrons can tunnel as a result of the magnetic breakdown from one FS sheet to another; their motion over magneticbreakdown trajectories becomes complicated and entangled. The thermoelectric field exhibits a peculiar dependence on the magnetic field: for a noticeable deviation of vector B from the normal through angle ϑ to the layers, the thermoelectric field oscillates as a function of tanϑ. The period of these oscillations contains important information on the distance between individual FS sheets and their corrugation.

  14. Tetrathiapentalene-based organic conductors

    International Nuclear Information System (INIS)

    Misaki, Yohji

    2009-01-01

    The synthesis, structure and properties of tetrathiapentalene-based (TTP) organic conductors are reviewed. Among various TTP-type donors, bis-fused tetrathiafulvalene, 2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene (BDT-TTP) and its derivatives afford many metallic radical cation salts stable down to low temperatures, regardless of the size and shape of the counter anions. Most BDT-TTP conductors have a β-type donor arrangement with almost uniform stacks. Introduction of appropriate substituents results in molecular packing that differs from the β-type. A vinylogous TTP, 2-(1,3-dithiol-2-ylidene)-5-(2-ethanediylidene-1,3-dithiole) -1,3,4,6-tetrathiapentalene (DTEDT) has yielded an organic superconductor (DTEDT) 3 Au(CN) 2 as well as metallic radical cation salts, regardless of the counter anions. (Thio)pyran analogs of TTP, namely (T)PDT-TTP and its derivatives produce molecular conductors with novel molecular arrangements. A TTP analog with reduced π-electron system 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene (BDA-TTP) has afforded several organic superconductors. Highly conducting molecular metals with unusual oxidation states (+1, +5/3 and neutral) have been developed on the basis of 2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene (BDT-TTP) derivatives and analogous metal derivatives M(dt) 2 (M = Ni, Au). (topical review)

  15. Method of installing well conductors

    International Nuclear Information System (INIS)

    Houser, D.M.

    1991-01-01

    This patent describes a method of installing a well conductor in a marine environment. It comprises sealing a well conductor with a watertight plug; submerging the conductor from an elevated platform; adding additional conductor lengths to the conductor as needed thereby forming a conductor string; adjusting the buoyancy of the string to control the lowering of the string to the sea floor; and drilling through the plug after the conductor string has achieved the desired penetration depth

  16. Tetrathiapentalene-based organic conductors

    Energy Technology Data Exchange (ETDEWEB)

    Misaki, Yohji, E-mail: misaki@eng.ehime-u.ac.j [Department of Applied Chemistry, Graduate School of Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama 790-8577 (Japan)

    2009-04-15

    The synthesis, structure and properties of tetrathiapentalene-based (TTP) organic conductors are reviewed. Among various TTP-type donors, bis-fused tetrathiafulvalene, 2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene (BDT-TTP) and its derivatives afford many metallic radical cation salts stable down to low temperatures, regardless of the size and shape of the counter anions. Most BDT-TTP conductors have a {beta}-type donor arrangement with almost uniform stacks. Introduction of appropriate substituents results in molecular packing that differs from the {beta}-type. A vinylogous TTP, 2-(1,3-dithiol-2-ylidene)-5-(2-ethanediylidene-1,3-dithiole) -1,3,4,6-tetrathiapentalene (DTEDT) has yielded an organic superconductor (DTEDT){sub 3}Au(CN){sub 2} as well as metallic radical cation salts, regardless of the counter anions. (Thio)pyran analogs of TTP, namely (T)PDT-TTP and its derivatives produce molecular conductors with novel molecular arrangements. A TTP analog with reduced {pi}-electron system 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene (BDA-TTP) has afforded several organic superconductors. Highly conducting molecular metals with unusual oxidation states (+1, +5/3 and neutral) have been developed on the basis of 2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene (BDT-TTP) derivatives and analogous metal derivatives M(dt){sub 2} (M = Ni, Au). (topical review)

  17. Possible mechanism to enhance spin-fluctuation-mediated superconductivity in two-dimensional organic conductor

    Energy Technology Data Exchange (ETDEWEB)

    Nonoyama, Yoshito; Maekawa, Yukiko; Kobayashi, Akito; Suzumura, Yoshikazu [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Yamada, Jun-ichi [Department of Material Science, Graduate School of Material Science, University of Hyogo, Hyogo 678-1297 (Japan)], E-mail: nonoyama@slab.phys.nagoya-u.ac.jp

    2008-10-15

    Mechanisms of superconductivity in quasi-two-dimensional organic conductors have been investigated using an extended Hubbard model by using the transfer energies between BDA-TTP molecules for {beta}-(BDA-TTP){sub 2}I{sub 3} based on the X-ray experiment data and the extended Hueckel calculation. We obtain several mean-field solutions with charge orderings which may represent short-range orderings or low-energy fluctuations in the low-dimensional electronic system. In the pressure-temperature phase diagram, a charge ordered metal state almost degenerates with a normal metal state between an insulating phase with charge ordering and the normal metal phase. Using the random phase approximation (RPA) and the linearized gap equation, the transition temperature of the superconducting state is estimated for the charge-ordered metal state and the normal metal state. It is found that transition temperature of the superconductivity induced by spin fluctuations in the charge-ordered metal state is much higher than that of the normal metal state and that the superconductivity in the charge-ordered metal state is the gapless d-wave. This suggests that the short range charge ordering may also contribute to an enhancement of spin-fluctuation-mediated superconductivity. The difference in the superconducting states between {beta}-(BDA-TTP){sub 2}I{sub 3} and {beta}-(BDA-TTP){sub 2}SbF{sub 6} are briefly discussed.

  18. Possible mechanism to enhance spin-fluctuation-mediated superconductivity in two-dimensional organic conductor

    International Nuclear Information System (INIS)

    Nonoyama, Yoshito; Maekawa, Yukiko; Kobayashi, Akito; Suzumura, Yoshikazu; Yamada, Jun-ichi

    2008-01-01

    Mechanisms of superconductivity in quasi-two-dimensional organic conductors have been investigated using an extended Hubbard model by using the transfer energies between BDA-TTP molecules for β-(BDA-TTP) 2 I 3 based on the X-ray experiment data and the extended Hueckel calculation. We obtain several mean-field solutions with charge orderings which may represent short-range orderings or low-energy fluctuations in the low-dimensional electronic system. In the pressure-temperature phase diagram, a charge ordered metal state almost degenerates with a normal metal state between an insulating phase with charge ordering and the normal metal phase. Using the random phase approximation (RPA) and the linearized gap equation, the transition temperature of the superconducting state is estimated for the charge-ordered metal state and the normal metal state. It is found that transition temperature of the superconductivity induced by spin fluctuations in the charge-ordered metal state is much higher than that of the normal metal state and that the superconductivity in the charge-ordered metal state is the gapless d-wave. This suggests that the short range charge ordering may also contribute to an enhancement of spin-fluctuation-mediated superconductivity. The difference in the superconducting states between β-(BDA-TTP) 2 I 3 and β-(BDA-TTP) 2 SbF 6 are briefly discussed.

  19. Fermi surface study of organic conductors using a magneto-optical measurement under high magnetic fields

    International Nuclear Information System (INIS)

    Kimata, M; Ohta, H; Koyama, K; Motokawa, M; Kondo, R; Kagoshima, S; Tanaka, H; Tokumoto, M; Kobayashi, H; Kobayashi, A

    2006-01-01

    Magneto-optical measurements have been performed in organic conductors β''-(BEDT-TTF) 2 CsCd(SCN) 4 and λ-(BETS) 2 FeCl 4 . Although the zero magnetic field ground state of β''-(BEDT-TTF) 2 CsCd(SCN) 4 is considered as the density wave state, periodic orbit resonances (POR's) attributed to quasi-one-dimensional (Q1D) and quasi-two-dimensional (Q2D) Fermi surfaces (FS's) have been observed above 6 T. The existence of these FS's are predicted by the band calculation based on room temperature lattice parameters. This result may suggest the destruction of the density wave state at 6 T, and the primal metallic state revives in the high field phase above 6 T. In the case of λ-(BETS) 2 FeCl 4 , large changes of the transmission intensity of electromagnetic waves around 10 T, which correspond to the insulator-metal transition, have been observed. However, no POR-like resonance has been observed. This may be due to the restriction of the observed frequency-field region

  20. Cyclotron resonance and De Haas-Van Alphen effect in (BEDT-TTF) sub 8 Hg sub 4 Cl sub 1 sub 2 (C sub 6 H sub 5 Cl) sub 2 organic conductor

    CERN Document Server

    Voskobojnikov, I B; Samarin, N A; Cluchanko, N E; Lyubovskaya, R N; Moshchalkov, V V

    2002-01-01

    Within 0.33-1.44 K temperature range at B <= 50 T magnetic field values one measured the De Haas-Van Alphen effect for (BEDT-TTF) sub 8 Hg sub 4 Cl sub 1 sub 2 (C sub 6 H sub 5 Cl) sub 2 organic quasi-two-dimensional conductor. Analysis of quantum oscillations with regard to data on cyclotron resonance derived for 40-120 GHz frequency interval enabled to determine that a complex spectrum of quantum oscillations was formed by alpha approx 256 T and beta approx 670-610 T fundamental frequencies as well as, by combination and multiple frequencies. It is shown that nature of temperature rearrangement of oscillation spectrum may be interpreted in terms of model taking account of occurrence of magnetic phase transition at T sub c approx 0.9 K and proximity of a fundamental frequency with m* = 1.48m sub 0 efficient mass to the spin dumping condition

  1. Storm on lightning conductors

    International Nuclear Information System (INIS)

    Broomhead, Laurent.

    1980-01-01

    Radioactive lightning conductors using radium or americium 241 sources are compared to Faraday cage and lightning rod. Americium source preparation is shortly described. Efficiency of the different systems is still controversed [fr

  2. Plasma Generator Using Spiral Conductors

    Science.gov (United States)

    Szatkowski, George N. (Inventor); Dudley, Kenneth L. (Inventor); Ticatch, Larry A. (Inventor); Smith, Laura J. (Inventor); Koppen, Sandra V. (Inventor); Nguyen, Truong X. (Inventor); Ely, Jay J. (Inventor)

    2016-01-01

    A plasma generator includes a pair of identical spiraled electrical conductors separated by dielectric material. Both spiraled conductors have inductance and capacitance wherein, in the presence of a time-varying electromagnetic field, the spiraled conductors resonate to generate a harmonic electromagnetic field response. The spiraled conductors lie in parallel planes and partially overlap one another in a direction perpendicular to the parallel planes. The geometric centers of the spiraled conductors define endpoints of a line that is non-perpendicular with respect to the parallel planes. A voltage source coupled across the spiraled conductors applies a voltage sufficient to generate a plasma in at least a portion of the dielectric material.

  3. Plasmonic transparent conductors

    Science.gov (United States)

    Liapis, Andreas C.; Sfeir, Matthew Y.; Black, Charles T.

    2016-09-01

    Many of today's technological applications, such as solar cells, light-emitting diodes, displays, and touch screens, require materials that are simultaneously optically transparent and electrically conducting. Here we explore transparent conductors based on the excitation of surface plasmons in nanostructured metal films. We measure both the optical and electrical properties of films perforated with nanometer-scale features and optimize the design parameters in order to maximize optical transmission without sacrificing electrical conductivity. We demonstrate that plasmonic transparent conductors can out-perform indium tin oxide in terms of both their transparency and their conductivity.

  4. Collective electromagnetic mode in layered conductors

    International Nuclear Information System (INIS)

    Gokhfel'd, V.M.; Peschanskij, V.G.

    1999-01-01

    In the frames of the Landau theory we consider the transverse zero-sound wave in a single-component charged Fermi-liquid with the quasi-two-dimensional electron energy spectrum. In such media, unlike conventional metals, the electromagnetic wave propagation along the weak conductivity direction is possible even at low intensity of the Fermi-liquid interaction. We find the field distribution in a sample, calculate the wave impedance and discuss the possibility of observation of the effect under the pulse condition

  5. Enhancement of the spontaneous emission in subwavelength quasi-two-dimensional waveguides and resonators

    Science.gov (United States)

    Tokman, Mikhail; Long, Zhongqu; AlMutairi, Sultan; Wang, Yongrui; Belkin, Mikhail; Belyanin, Alexey

    2018-04-01

    We consider a quantum-electrodynamic problem of the spontaneous emission from a two-dimensional (2D) emitter, such as a quantum well or a 2D semiconductor, placed in a quasi-2D waveguide or cavity with subwavelength confinement in one direction. We apply the Heisenberg-Langevin approach, which includes dissipation and fluctuations in the electron ensemble and in the electromagnetic field of a cavity on equal footing. The Langevin noise operators that we introduce do not depend on any particular model of dissipative reservoir and can be applied to any dissipation mechanism. Moreover, our approach is applicable to nonequilibrium electron systems, e.g., in the presence of pumping, beyond the applicability of the standard fluctuation-dissipation theorem. We derive analytic results for simple but practically important geometries: strip lines and rectangular cavities. Our results show that a significant enhancement of the spontaneous emission, by a factor of order 100 or higher, is possible for quantum wells and other 2D emitters in a subwavelength cavity.

  6. Coexistence of superconductivity and density waves in quasi-two-dimensional metals

    Energy Technology Data Exchange (ETDEWEB)

    Ismer, Jan-Peter

    2011-06-03

    This dissertation deals with the high-temperature superconductivity in the hole- and electron-doped copper superconductors. In the first part, superconducting phases are investigated on a background of different types of density waves. Singlet superconductivity is studied with s- and d-wave symmetry on a background of spin, charge or D-density waves with respect to stability as well as phase structure and impulse dependence of the gap function. In the second part, the dynamic spin susceptibility for different phases is calculated and compared with experimental data extracted from results of inelastic neutron scattering experiments. The observed phases are d-wave superconductivity, D-density wave, and coexistence of the two. For d-wave superconductivity, the influence of a magnetic field parallel to the copper oxide layer and the temperature development of the susceptibility when for T >> T{sub c} a spin density wave phase is present are investigated. [German] Diese Dissertation beschaeftigt sich mit der Hochtemperatursupraleitung in den loch- und elektron-dotierten Kuprat-Supraleitern. Im ersten Teil der Arbeit werden supraleitende Phasen auf einem Hintergrund verschiedener Typen von Dichtewellen untersucht. Es wird Singlett-Supraleitung mit s- und d-Wellen-Symmetrie auf einem Hintergrund von Spin-, Ladungs- oder D-Dichtewelle hinsichtlich Stabilitaet sowie Phasenstruktur und Impulsabhaengigkeit der Gapfunktion untersucht. Im zweiten Teil wird die dynamische Spinsuszeptibilitaet fuer verschiedene Phasen berechnet und mit experimentellen Daten verglichen, die aus Ergebnissen von Inelastischen Neutronenstreuungsexperimenten extrahiert wurden. Die betrachteten Phasen sind d-Wellen-Supraleitung, D-Dichtewelle und Koexistenz der beiden. Fuer d-Wellen-Supraleitung werden der Einfluss eines Magnetfelds parallel zur Kupferoxidschicht und die Temperaturentwicklung der Suszeptibilitaet, wenn fuer T >> T{sub c} eine Spin-Dichtewelle-Phase vorliegt, untersucht.

  7. Layer-dependent anisotropic electronic structure of freestanding quasi-two-dimensional Mo S 2

    KAUST Repository

    Hong, Jinhua; Li, Kun; Jin, Chuanhong; Zhang, Xixiang; Zhang, Ze; Yuan, Jun

    2016-01-01

    The anisotropy of the electronic transition is a well-known characteristic of low-dimensional transition-metal dichalcogenides, but their layer-thickness dependence has not been properly investigated experimentally until now. Yet, it not only determines the optical properties of these low-dimensional materials, but also holds the key in revealing the underlying character of the electronic states involved. Here we used both angle-resolved electron energy-loss spectroscopy and spectral analysis of angle-integrated spectra to study the evolution of the anisotropic electronic transition involving the low-energy valence electrons in the freestanding MoS2 layers with different thicknesses. We are able to demonstrate that the well-known direct gap at 1.8 eV is only excited by the in-plane polarized field while the out-of-plane polarized optical gap is 2.4 ± 0.2 eV in monolayer MoS2. This contrasts with the much smaller anisotropic response found for the indirect gap in the few-layer MoS2 systems. In addition, we determined that the joint density of states associated with the indirect gap transition in the multilayer systems and the corresponding indirect transition in the monolayer case has a characteristic three-dimensional-like character. We attribute this to the soft-edge behavior of the confining potential and it is an important factor when considering the dynamical screening of the electric field at the relevant excitation energies. Our result provides a logical explanation for the large sensitivity of the indirect transition to thickness variation compared with that for the direct transition, in terms of quantum confinement effect.

  8. Magnetic Weyl Semimetal in Quasi Two-dimensional Half Metallic Co$_3$Sn$_2$Se$_2$

    OpenAIRE

    Xu, Qiunan; Liu, Enke; Shi, Wujun; Muechler, Lukas; Felser, Claudia; Sun, Yan

    2017-01-01

    We have found a ferromagnetic Weyl semimetal (WSM) in half metallic Co$_3$Sn$_2$Se$_2$. The three pairs of Weyl points near Fermi level (E$_F$) are derived from nodal lines gapped by spin-orbit coupling (SOC). Though the Weyl points are 0.11 eV above the charge neutral point, Fermi arc related states in the cleaved surface can range from E$_F$ -0.15 to E$_F$ +0.11 eV in energy space, due to the surface bands dispersion. Hence, Weyl points related physics should be detected by surface measurem...

  9. Stress relaxation in quasi-two-dimensional self-assembled nanoparticle monolayers

    Science.gov (United States)

    Boucheron, Leandra S.; Stanley, Jacob T.; Dai, Yeling; You, Siheng Sean; Parzyck, Christopher T.; Narayanan, Suresh; Sandy, Alec R.; Jiang, Zhang; Meron, Mati; Lin, Binhua; Shpyrko, Oleg G.

    2018-05-01

    We experimentally probed the stress relaxation of a monolayer of iron oxide nanoparticles at the water-air interface. Upon drop-casting onto a water surface, the nanoparticles self-assembled into islands of two-dimensional hexagonally close packed crystalline domains surrounded by large voids. When compressed laterally, the voids gradually disappeared as the surface pressure increased. After the compression was stopped, the surface pressure (as measured by a Wilhelmy plate) evolved as a function of the film aging time with three distinct timescales. These aging dynamics were intrinsic to the stressed state built up during the non-equilibrium compression of the film. Utilizing x-ray photon correlation spectroscopy, we measured the characteristic relaxation time (τ ) of in-plane nanoparticle motion as a function of the aging time through both second-order and two-time autocorrelation analysis. Compressed and stretched exponential fitting of the intermediate scattering function yielded exponents (β ) indicating different relaxation mechanisms of the films under different compression stresses. For a monolayer compressed to a lower surface pressure (between 20 mN/m and 30 mN/m), the relaxation time (τ ) decreased continuously as a function of the aging time, as did the fitted exponent, which transitioned from being compressed (>1 ) to stretched (stress release through crystalline domain reorganization. However, for a monolayer compressed to a higher surface pressure (around 40 mN/m), the relaxation time increased continuously and the compressed exponent varied very little from a value of 1.6, suggesting that the system may have been highly stressed and jammed. Despite the interesting stress relaxation signatures seen in these samples, the structural ordering of the monolayer remained the same over the sample lifetime, as revealed by grazing incidence x-ray diffraction.

  10. Layer-dependent anisotropic electronic structure of freestanding quasi-two-dimensional Mo S 2

    KAUST Repository

    Hong, Jinhua

    2016-02-29

    The anisotropy of the electronic transition is a well-known characteristic of low-dimensional transition-metal dichalcogenides, but their layer-thickness dependence has not been properly investigated experimentally until now. Yet, it not only determines the optical properties of these low-dimensional materials, but also holds the key in revealing the underlying character of the electronic states involved. Here we used both angle-resolved electron energy-loss spectroscopy and spectral analysis of angle-integrated spectra to study the evolution of the anisotropic electronic transition involving the low-energy valence electrons in the freestanding MoS2 layers with different thicknesses. We are able to demonstrate that the well-known direct gap at 1.8 eV is only excited by the in-plane polarized field while the out-of-plane polarized optical gap is 2.4 ± 0.2 eV in monolayer MoS2. This contrasts with the much smaller anisotropic response found for the indirect gap in the few-layer MoS2 systems. In addition, we determined that the joint density of states associated with the indirect gap transition in the multilayer systems and the corresponding indirect transition in the monolayer case has a characteristic three-dimensional-like character. We attribute this to the soft-edge behavior of the confining potential and it is an important factor when considering the dynamical screening of the electric field at the relevant excitation energies. Our result provides a logical explanation for the large sensitivity of the indirect transition to thickness variation compared with that for the direct transition, in terms of quantum confinement effect.

  11. Nanofluidic electrokinetics in quasi-two-dimensional branched U-turn channels

    NARCIS (Netherlands)

    Parikesit, G.O.F.

    2008-01-01

    Lab-on-a-Chip (LOC) is a new technology focused on analyzing and controlling flows of fluids, ions, and (bio) particles on the nanometer and micrometer scales, allowing us to shrink a complete fluid-based laboratory into a coin-sized instrumentation. In this thesis, we study a novel fluidic

  12. Quasi-two-dimensional metallic hydrogen inside di-phosphide at high pressure

    International Nuclear Information System (INIS)

    Degtyarenko, N N; Mazur, E A

    2016-01-01

    The method of mathematical modelling was used for the calculation of the structural, electronic, phononic, and other characteristics of various normal phases of phosphorus hydrides with stoichiometry PH k . It was shown that the di-phosphine may form 2D lattice of the metallic hydrogen in it, stabilized by phosphorus atoms under high hydrostatic pressure. The resulting structure with the elements of H-P-H has a locally stable (or metastable) phonon spectrum. The properties of di-phosphine were compared with the properties of similar structures such as the sulphur hydrides. (paper)

  13. Block copolymer micelle coronas as quasi-two-dimensional dilute or semidilute polymer solutions

    DEFF Research Database (Denmark)

    Svaneborg, C.; Pedersen, J.S.

    2001-01-01

    Chain-chain interactions in a corona of polymers tethered to a spherical core under good solvent conditions are studied using Monte Carlo simulations. The total scattering function of the corona as well as different partial contributions are sampled. By combining the different contributions...

  14. Final Report - Composite Fermion Approach to Strongly Interacting Quasi Two Dimensional Electron Gas Systems

    Energy Technology Data Exchange (ETDEWEB)

    Quinn, John

    2009-11-30

    Work related to this project introduced the idea of an effective monopole strength Q* that acted as the effective angular momentum of the lowest shell of composite Fermions (CF). This allowed us to predict the angular momentum of the lowest band of energy states for any value of the applied magnetic field simply by determining N{sub QP} the number of quasielectrons (QE) or quasiholes (QH) in a partially filled CF shell and adding angular momenta of the N{sub QP} Fermions excitations. The approach reported treated the filled CF level as a vacuum state which could support QE and QH excitations. Numerical diagonalization of small systems allowed us to determine the angular momenta, the energy, and the pair interaction energies of these elementary excitations. The spectra of low energy states could then be evaluated in a Fermi liquid-like picture, treating the much smaller number of quasiparticles and their interactions instead of the larger system of N electrons with Coulomb interactions.

  15. Nonequilibrium Dynamics in a Quasi-Two-Dimensional Electron Plasma after Ultrafast Intersubband Excitation

    International Nuclear Information System (INIS)

    Lutgen, S.; Kaindl, R.A.; Woerner, M.; Elsaesser, T.; Hase, A.; Kuenzel, H.; Gulia, M.; Meglio, D.; Lugli, P.

    1996-01-01

    The dynamics of electrons in GaInAs/AlInAs quantum wells is studied after excitation from the n=1 to the n=2 conduction subband. Femtosecond pump-probe experiments demonstrate for the first time athermal distributions of n=1 electrons on a surprisingly long time scale of 2ps. Thermalization involves intersubband scattering of excited electrons via optical phonon emission with a time constant of 1ps and intrasubband Coulomb and phonon scattering. Ensemble Monte Carlo simulations show that the slow electron equilibration results from Pauli blocking and screening of carrier-carrier scattering. copyright 1996 The American Physical Society

  16. Direct observation of strong localization of quasi-two-dimensional light waves

    DEFF Research Database (Denmark)

    Bozhevolnyi, Sergey I.

    1999-01-01

    Scattering of surface plasmon polaritons on rough metal surfaces is investigated by using scanning near-field optical microscopy. Different scattering regimes, i.e. single, double and multiple scattering, are observed and related to the spatial Fourier spectra of the corresponding near-field opti...... caused by surface roughness. Similar bright light spots are observed with light scattering by silver colloid clusters deposited on glass substrates. Differences and similarities in these scattering phenomena are discussed....

  17. Quasi-two-dimensional superconductivity in wurtzite-structured InN films

    International Nuclear Information System (INIS)

    Ling, D.C.; Cheng, J.H.; Lo, Y.Y.; Du, C.H.; Chiu, A.P.; Chang, P.H.; Chang, C.A.

    2007-01-01

    C-axis oriented InN films with wurtzite structure were grown on sapphire(0001) substrate by MOCVD method. Superconductivity with transition onset temperature T c,onset around 3.5 K has been characterized by magnetotransport measurements in fields up to 9 Tesla for films with carrier concentration in the range of 1 x 10 19 cm -3 to 7 x 10 20 cm -3 . Among them, the film with a nitridation buffer layer has the highest zero-resistance temperature T c0 of 2 K. The normal-state magnetoresistance follows Kohler's rule ΔR/R∝(H/R) 2 , indicating that there is a single species of charge carrier with single scattering time at all points on the Fermi surface. The extrapolated value of zero-temperature upper critical field H c2 ab (0) and H c2 c (0) is estimated to be 5900 G and 2800 G, respectively, giving rise to the anisotropy parameter γ about 2.1. The angular dependence of the upper critical field is in good agreement with the behavior predicted by Lawrence-Doniach model in the two-dimensional (2D) limit strongly suggesting that the InN film is a quasi-2D superconductor. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Decaying quasi-two-dimensional viscous flow on a square domain

    DEFF Research Database (Denmark)

    Konijnenberg, J.A. van de; Flor, J.B.; Heijst, G.J.F. van

    1998-01-01

    A comparison is made between experimental, numerical and analytical results for the two-dimensional flow on a square domain. The experiments concern the flow at the interface of a two-layer stratified fluid, evoked by either stirring the fluid with a rake, or by injecting additional fluid...... at the interface. Two numerical simulations were performed with initial conditions and boundary conditions that correspond approximately with those met in the experiments. The analytical results concern the calculation of the lowest modes of a decaying Stokes flow on a square domain. At late times...... relationship between vorticity and stream function in the experiments and the simulations. (C) 1998 American Institute of Physics....

  19. Quasi-particle properties in a quasi-two-dimensional electron liquid

    Indian Academy of Sciences (India)

    effects are incorporated into the local-field factors that describe the charge and spin correla- ... dient of which is the quasi-particle concept and its interactions. .... factors. Note that we have approximated the local-field factors by their static, frequency-independent limits. Quite generally, once the QP self-energy is known, the ...

  20. Spin eigen-states of Dirac equation for quasi-two-dimensional electrons

    Energy Technology Data Exchange (ETDEWEB)

    Eremko, Alexander, E-mail: eremko@bitp.kiev.ua [Bogolyubov Institute for Theoretical Physics, Metrologichna Sttr., 14-b, Kyiv, 03680 (Ukraine); Brizhik, Larissa, E-mail: brizhik@bitp.kiev.ua [Bogolyubov Institute for Theoretical Physics, Metrologichna Sttr., 14-b, Kyiv, 03680 (Ukraine); Loktev, Vadim, E-mail: vloktev@bitp.kiev.ua [Bogolyubov Institute for Theoretical Physics, Metrologichna Sttr., 14-b, Kyiv, 03680 (Ukraine); National Technical University of Ukraine “KPI”, Peremohy av., 37, Kyiv, 03056 (Ukraine)

    2015-10-15

    Dirac equation for electrons in a potential created by quantum well is solved and the three sets of the eigen-functions are obtained. In each set the wavefunction is at the same time the eigen-function of one of the three spin operators, which do not commute with each other, but do commute with the Dirac Hamiltonian. This means that the eigen-functions of Dirac equation describe three independent spin eigen-states. The energy spectrum of electrons confined by the rectangular quantum well is calculated for each of these spin states at the values of energies relevant for solid state physics. It is shown that the standard Rashba spin splitting takes place in one of such states only. In another one, 2D electron subbands remain spin degenerate, and for the third one the spin splitting is anisotropic for different directions of 2D wave vector.

  1. Physics of superionic conductors

    CERN Document Server

    1979-01-01

    Superionic conductors are solids whose ionic conductivities approach, and in some cases exceed, those of molten salts and electrolyte solutions. This implies an un­ usual state of matter in which some atoms have nearly liquidlike mobility while others retain their regular crystalline arrangement. This liquid-solid duality has much appeal to condensed matter physicists, and the coincident development of powerful new methods for studying disordered solids and interest in superionic conductors for technical applications has resulted in a new surge of activity in this venerable field. It is the purpose of this book to summarize the current re­ search in the physics of superionic conduction. with special emphasis on those aspects which set these materials apart from other solids. The volume is aimed to­ wards the materials community and will, we expect, stimulate further research on these potentially useful substances. The usual characterization of the superionic phase lists high ionic conductivity; low activat...

  2. Organic Conductors: Evidence for Correlation Effects in Infrared Properties

    DEFF Research Database (Denmark)

    Jacobsen, Claus Schelde; Johannsen, Ib; Bechgaard, Klaus

    1984-01-01

    The infrared conductivities of four organic conductors with partially filled one-electron bands are compared. The behavior ranges from near Drude type in the best metal to semiconductorlike in the moderate conductor. Electron-molecular-vibration coupling effects of varying degree are seen in all...... materials. It is suggested that the combined effect of electron-electron interaction and electron-phonon interaction in producing 4kF charge-density waves is essential for interpreting the results....

  3. The CMS conductor

    CERN Document Server

    Horváth, I L; Marti, H P; Neuenschwander, J; Smith, R P; Fabbricatore, P; Musenich, R; Calvo, A; Campi, D; Curé, B; Desirelli, Alberto; Favre, G; Riboni, P L; Sgobba, Stefano; Tardy, T; Sequeira-Lopes-Tavares, S

    2000-01-01

    The Compact Muon Solenoid (CMS) is one of the experiments, which are being designed in the framework of the Large Hadron Collider (LHC) project at CERN, the design field of the CMS magnet is 4 T, the magnetic length is 13 m and the aperture is 6 m. This high magnetic field is achieved by means of a 4 layer, 5 modules superconducting coil. The coil is wound from an Al-stabilized Rutherford type conductor. The nominal current of the magnet is 20 kA at 4.5 K. In the CMS coil the structural function is ensured, unlike in other existing Al-stabilized thin solenoids, both by the Al-alloy reinforced conductor and the external former. In this paper the retained manufacturing process of the 50-km long reinforced conductor is described. In general the Rutherford type cable is surrounded by high purity aluminium in a continuous co-extrusion process to produce the Insert. Thereafter the reinforcement is joined by Electron Beam Welding to the pure Al of the insert, before being machined to the final dimensions. During the...

  4. Interacting with a Virtual Conductor

    NARCIS (Netherlands)

    Bos, Pieter; Reidsma, Dennis; Ruttkay, Zsófia; Nijholt, Anton; Harper, Richard; Rauterberg, Matthias; Combetto, Marco

    This paper presents a virtual embodied agent that can conduct musicians in a live performance. The virtual conductor conducts music specified by a MIDI file and uses input from a microphone to react to the tempo of the musicians. The current implementation of the virtual conductor can interact with

  5. Understanding core conductor fabrics

    International Nuclear Information System (INIS)

    Swenson, D E

    2011-01-01

    ESD Association standard test method ANSI/ESD STM2.1 - Garments (STM2.1), provides electrical resistance test procedures that are applicable for materials and garments that have surface conductive or surface dissipative properties. As has been reported in other papers over the past several years 1 fabrics are now used in many industries for electrostatic control purposes that do not have surface conductive properties and therefore cannot be evaluated using the procedures in STM2.1 2 . A study was conducted to compare surface conductive fabrics with samples of core conductor fibre based fabrics in order to determine differences and similarities with regards to various electrostatic properties. This work will be used to establish a new work item proposal within WG-2, Garments, in the ESD Association Standards Committee in the USA.

  6. Magnetism and Pressure-Induced Superconductivity of Checkerboard-Type Charge-Ordered Molecular Conductor β-(meso-DMBEDT-TTF2X (X = PF6 and AsF6

    Directory of Open Access Journals (Sweden)

    Yutaka Nishio

    2012-11-01

    Full Text Available The metallic state of the molecular conductor β-(meso-DMBEDT-TTF2X (DMBEDT-TTF = 2-(5,6-dihydro-1,3-dithiolo[4,5-b][1,4]dithiin-2-ylidene-5,6-dihydro-5,6-dimethyl-1,3-dithiolo[4,5-b][1,4]dithiin, X = PF6, AsF6 is transformed into the checkerboard-type charge-ordered state at around 75–80 K with accompanying metal-insulator (MI transition on the anisotropic triangular lattice. With lowering temperatures, the magnetic susceptibility decreases gradually and reveals a sudden drop at the MI transition. By applying pressure, the charge-ordered state is suppressed and superconductivity appears in β-(meso-DMBEDT-TTF2AsF6 as well as in the reported β-(meso-DMBEDT-TTF2PF6. The charge-ordered spin-gapped state and the pressure-induced superconducting state are discussed through the paired-electron crystal (PEC model, where the spin-bonded electron pairs stay and become mobile in the crystal, namely the valence-bond solid (VBS and the resonant valence bonded (RVB state in the quarter-filled band structure.

  7. Conductor for a fluid-cooled winding

    Science.gov (United States)

    Kenney, Walter J.

    1983-01-01

    A conductor and method of making the conductor are provided for use in winding electrical coils which are cooled by a fluid communicating with the conductor. The conductor is cold worked through twisting and reshaping steps to form a generally rectangular cross section conductor having a plurality of helical cooling grooves extending axially of the conductor. The conductor configuration makes it suitable for a wide variety of winding applications and permits the use of simple strip insulation between turns and perforated sheet insulation between layers of the winding.

  8. Molecular dynamics studies of superionic conductors

    International Nuclear Information System (INIS)

    Rahman, A.

    1979-01-01

    Over the last fifteen years computer modeling of liquids and solids has become a useful method of understanding the structural and dynamical correlations in these systems. Some characteristics of the method are presented with an example from work on homogeneous nucleation in monoatomic liquids; the interaction potential determines the structure: a Lennard--Jones system nucleates a close packed structure while an alkali metal potential nucleates a bcc packing. In the study of ionic systems like CaF 2 the Coulomb interaction together with the short range repulsion is enough to produce a satisfactory model for the motion of F - ions in CaF 2 at approx. 1600 0 K. Analysis of this motion shows that F - ions reside at their fluorite sites for about 6 x 10 -12 s and that the diffusion is mainly due to F - jumps in the 100 direction. The motion can be analyzed in terms of the generation and annihilation of anti-Frenkel pairs. The temperature dependence of the F - diffusion constant at two different densities has also been calculated. The computer model does not correspond with experiment in this regard

  9. High Critical Current Coated Conductors

    Energy Technology Data Exchange (ETDEWEB)

    Paranthaman, M. P.; Selvamanickam, V. (SuperPower, Inc.)

    2011-12-27

    One of the important critical needs that came out of the DOE’s coated conductor workshop was to develop a high throughput and economic deposition process for YBCO. Metal-organic chemical vapor deposition (MOCVD) technique, the most critical steps in high technical micro fabrications, has been widely employed in semiconductor industry for various thin film growth. SuperPower has demonstrated that (Y,Gd)BCO films can be deposited rapid with world record performance. In addition to high critical current density with increased film thickness, flux pinning properties of REBCO films needs to be improved to meet the DOE requirements for various electric-power equipments. We have shown that doping with Zr can result in BZO nanocolumns, but at substantially reduced deposition rate. The primary purpose of this subtask is to develop high current density MOCVD-REBCO coated conductors based on the ion-beam assisted (IBAD)-MgO deposition process. Another purpose of this subtask is to investigate HTS conductor design optimization (maximize Je) with emphasis on stability and protection issues, and ac loss for REBCO coated conductors.

  10. Power distribution: conductors in aluminium

    International Nuclear Information System (INIS)

    Schmid, R.

    2007-01-01

    This article takes a look at the use of aluminium conductors in medium and low-voltage cables. The author discusses how the increasing price of copper has led to the increasing use of aluminium as a material for the production of the conductors used in medium and low-voltage power cables. Aid is provided that is to help purchasers make the correct decisions when buying medium and low-voltage cables. The current market situation is examined and the appropriate norms are looked at. Technical data and economic aspects are discussed, both for medium and low-voltage applications. The electrical characteristics of the type of cable to be used are examined and discussed

  11. Pulse Propagation on close conductors

    CERN Document Server

    Dieckmann, A

    2001-01-01

    The propagation and reflection of arbitrarily shaped pulses on non-dispersive parallel conductors of finite length with user defined cross section is simulated employing the discretized telegraph equation. The geometry of the system of conductors and the presence of dielectric material determine the capacities and inductances that enter the calculation. The values of these parameters are found using an iterative Laplace equation solving procedure and confirmed for certain calculable geometries including the line charge inside a box. The evolving pulses and the resulting crosstalk can be plotted at any instant and - in the Mathematica notebook version of this report - be looked at in an animation. As an example a differential pair of microstrips as used in the ATLAS vertex detector is analysed.

  12. Composite conductor containing superconductive wires

    Energy Technology Data Exchange (ETDEWEB)

    Larson, W.L.; Wong, J.

    1974-03-26

    A superconductor cable substitute made by coworking multiple rods of superconductive niobium--titanium or niobium--zirconium alloy with a common copper matrix to extend the copper and rods to form a final elongated product which has superconductive wires distributed in a reduced cross-section copper conductor with a complete metallurgical bond between the normal-conductive copper and the superconductor wires contained therein is described. The superconductor cable can be in the form of a tube.

  13. Coated Conductors under Tensile Stress

    International Nuclear Information System (INIS)

    Antonevici, Anca; Villaume, Alain; Villard, Catherine; Sulpice, Andre; Maron, Pierre Brosse; Bourgault, Daniel; Porcar, Laureline

    2006-01-01

    Critical current dependence versus strain is obtained for in-situ axial stress experiments on ISD YBCO and DyBCO coated conductors. The drop of critical current due to the apparition of first cracks in the superconducting ceramics is related to the passage in the plastic region of the substrate for a strain of about 0.3% and a stress higher then 500MPa. The superconductivity is preserved between the cracks

  14. Temperature limited heater utilizing non-ferromagnetic conductor

    Science.gov (United States)

    Vinegar,; Harold J. , Harris; Kelvin, Christopher [Houston, TX

    2012-07-17

    A heater is described. The heater includes a ferromagnetic conductor and an electrical conductor electrically coupled to the ferromagnetic conductor. The ferromagnetic conductor is positioned relative to the electrical conductor such that an electromagnetic field produced by time-varying current flow in the ferromagnetic conductor confines a majority of the flow of the electrical current to the electrical conductor at temperatures below or near a selected temperature.

  15. Measurement of correlations between low-frequency vibrational modes and particle rearrangements in quasi-two-dimensional colloidal glasses

    NARCIS (Netherlands)

    Chen, K.; Manning, M.L.; Yunker, P.J.; Ellenbroek, W.G.; Zhang, Zexin; Liu, Andrea J.; Yodh, A.G.

    2011-01-01

    We investigate correlations between low-frequency vibrational modes and rearrangements in two-dimensional colloidal glasses composed of thermosensitive microgel particles, which readily permit variation of the sample packing fraction. At each packing fraction, the particle displacement covariance

  16. Measurement of correlations between low-frequency vibrational modes and particle rearrangements in quasi-two-dimensional colloidal glasses.

    Science.gov (United States)

    Chen, Ke; Manning, M L; Yunker, Peter J; Ellenbroek, Wouter G; Zhang, Zexin; Liu, Andrea J; Yodh, A G

    2011-09-02

    We investigate correlations between low-frequency vibrational modes and rearrangements in two-dimensional colloidal glasses composed of thermosensitive microgel particles, which readily permit variation of the sample packing fraction. At each packing fraction, the particle displacement covariance matrix is measured and used to extract the vibrational spectrum of the "shadow" colloidal glass (i.e., the particle network with the same geometry and interactions as the sample colloid but absent damping). Rearrangements are induced by successive, small reductions in the packing fraction. The experimental results suggest that low-frequency quasilocalized phonon modes in colloidal glasses, i.e., modes that present low energy barriers for system rearrangements, are spatially correlated with rearrangements in this thermal system.

  17. Pressure dependence of the Peierls transition in the quasi two-dimensional purple bronze KMo 6O 17

    Science.gov (United States)

    Rötger, A.; Beille, J.; Laurant, J. M.; Schlenker, C.

    1993-09-01

    The electrical resistivity and the lattice parameters have been studied as a function of pressure on the quasi-twodimensional purple bronze KMo 6O 17 which shows a Peierls transition towards a commensurate charge density wave state. The Peierls temperature is found to be first slightly decreased for pressures smaller than 6 kbar, then strongly increased above. This increase is associated to an anomalous contraction of the lattice parameters in the plane of the layers. The corresponding large increase of the compressibility above 16 kbar at 300 K is associated to the pretransitional regime of the Peierls transition as a function of pressure. These results are attributed mainly to an improved nesting of the Fermi surface under pressure.

  18. Commensurability oscillations in a quasi-two-dimensional electron gas subject to strong in-plane magnetic field

    Czech Academy of Sciences Publication Activity Database

    Smrčka, Ludvík

    2016-01-01

    Roč. 77, Mar (2016), s. 108-113 ISSN 1386-9477 Institutional support: RVO:68378271 Keywords : lateral superlattices * commensurability oscillations * in-plane magnetic field Subject RIV: BE - Theoretical Physics Impact factor: 2.221, year: 2016

  19. Quasi Two-Dimensional Dye-Sensitized In 2 O 3 Phototransistors for Ultrahigh Responsivity and Photosensitivity Photodetector Applications

    KAUST Repository

    Mottram, Alexander D.; Lin, Yen-Hung; Pattanasattayavong, Pichaya; Zhao, Kui; Amassian, Aram; Anthopoulos, Thomas D.

    2016-01-01

    of the light absorbing organic dye D102. The resulting transistors exhibit a preferential color photoresponse centered in the wavelength region of ∼500 nm with a maximum photosensitivity of ∼106 and a responsivity value of up to 2 × 103 A/W. The high

  20. Quasi Two-Dimensional Dye-Sensitized In 2 O 3 Phototransistors for Ultrahigh Responsivity and Photosensitivity Photodetector Applications

    KAUST Repository

    Mottram, Alexander D.

    2016-02-10

    © 2016 American Chemical Society. We report the development of dye-sensitized thin-film phototransistors consisting of an ultrathin layer (<10 nm) of indium oxide (In2O3) the surface of which is functionalized with a self-assembled monolayer of the light absorbing organic dye D102. The resulting transistors exhibit a preferential color photoresponse centered in the wavelength region of ∼500 nm with a maximum photosensitivity of ∼106 and a responsivity value of up to 2 × 103 A/W. The high photoresponse is attributed to internal signal gain and more precisely to charge carriers generated upon photoexcitation of the D102 dye which lead to the generation of free electrons in the semiconducting layer and to the high photoresponse measured. Due to the small amount of absorption of visible photons, the hybrid In2O3/D102 bilayer channel appears transparent with an average optical transmission of >92% in the wavelength range 400-700 nm. Importantly, the phototransistors are processed from solution-phase at temperatures below 200 °C hence making the technology compatible with inexpensive and temperature sensitive flexible substrate materials such as plastic.

  1. Isotropic-nematic transition of long, thin, hard spherocylinders confined in a quasi-two-dimensional planar geometry

    NARCIS (Netherlands)

    Lagomarsino, M.C.; Dogterom, M.; Dijkstra, Marjolein

    2003-01-01

    We present computer simulations of long, thin, hard spherocylinders in a narrow planar slit. We observe a transition from the isotropic to a nematic phase with quasi-long-range orientational order upon increasing the density. This phase transition is intrinsically two-dimensional and of

  2. Ab initio electronic structure of quasi-two-dimensional materials: A “native” Gaussian–plane wave approach

    Energy Technology Data Exchange (ETDEWEB)

    Trevisanutto, Paolo E. [Graphene Research Centre and CA2DM, National University of Singapore, Singapore 117542, Singapore and Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603 (Singapore); Vignale, Giovanni, E-mail: vignaleg@missouri.edu [Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211 (United States)

    2016-05-28

    Ab initio electronic structure calculations of two-dimensional layered structures are typically performed using codes that were developed for three-dimensional structures, which are periodic in all three directions. The introduction of a periodicity in the third direction (perpendicular to the layer) is completely artificial and may lead in some cases to spurious results and to difficulties in treating the action of external fields. In this paper we develop a new approach, which is “native” to quasi-2D materials, making use of basis function that are periodic in the plane, but atomic-like in the perpendicular direction. We show how some of the basic tools of ab initio electronic structure theory — density functional theory, GW approximation and Bethe-Salpeter equation — are implemented in the new basis. We argue that the new approach will be preferable to the conventional one in treating the peculiarities of layered materials, including the long range of the unscreened Coulomb interaction in insulators, and the effects of strain, corrugations, and external fields.

  3. Critical behavior of magnetization in URhAl: Quasi-two-dimensional Ising system with long-range interactions

    Science.gov (United States)

    Tateiwa, Naoyuki; Pospíšil, Jiří; Haga, Yoshinori; Yamamoto, Etsuji

    2018-02-01

    The critical behavior of dc magnetization in the uranium ferromagnet URhAl with the hexagonal ZrNiAl-type crystal structure has been studied around the ferromagnetic transition temperature TC. The critical exponent β for the temperature dependence of the spontaneous magnetization below TC,γ for the magnetic susceptibility, and δ for the magnetic isotherm at TC, have been obtained with a modified Arrott plot, a Kouvel-Fisher plot, the critical isotherm analysis, and the scaling analysis. We have determined the critical exponents as β =0.287 ±0.005 , γ =1.47 ±0.02 , and δ =6.08 ±0.04 by the scaling analysis and the critical isotherm analysis. These critical exponents satisfy the Widom scaling law δ =1 +γ /β . URhAl has strong uniaxial magnetic anisotropy, similar to its isostructural UCoAl that has been regarded as a three-dimensional (3D) Ising system in previous studies. However, the universality class of the critical phenomenon in URhAl does not belong to the 3D Ising model (β =0.325 , γ =1.241 , and δ =4.82 ) with short-range exchange interactions between magnetic moments. The determined exponents can be explained with the results of the renormalization group approach for a two-dimensional (2D) Ising system coupled with long-range interactions decaying as J (r ) ˜r-(d +σ ) with σ =1.44 . We suggest that the strong hybridization between the uranium 5 f and rhodium 4 d electrons in the U-RhI layer in the hexagonal crystal structure is a source of the low-dimensional magnetic property. The present result is contrary to current understandings of the physical properties in a series of isostructural UTX uranium ferromagnets (T: transition metals, X: p -block elements) based on the 3D Ising model.

  4. Transparent conductor based on aluminum nanomesh

    International Nuclear Information System (INIS)

    Kazarkin, B; Mohammed, A S; Stsiapanau, A; Zhuk, S; Satskevich, Y; Smirnov, A

    2014-01-01

    We report a transparent conductor based on Al nanomesh, which was fabricated through Al anodization and etching processes. The Al anodization was performed at low temperature condition to slow down the anodization rate to achieve the well-controlled thickness of an Al nanomesh. By careful controlling of the anodization process, we can fabricate Al nanomesh transparent conductors with different sheet resistance and optical transparency in the visible spectrum range. We shall show that Al nanomesh transparent conductor is a strong contender for a transparent conductor dominated by ITO

  5. Fabrication process of a superconducting multifilament conductor of a cable and resulting electric conductor

    International Nuclear Information System (INIS)

    Fevrier, A.; Verhaege, T.; Bonnet, P.

    1990-01-01

    Elementary conductors constituted of a plurality of superconducting filaments in a metallic matrix are prepared and then twisted. Elementary conductors with a diameter between 0.05 and 0.25 mm without electric insulation are twisted after heating with a pitch of four time the diameter, finally the conductor is insulated [fr

  6. Molecular dynamics studies of the melting of butane and hexane monolayers adsorbed on the basal-plane surface of graphite

    DEFF Research Database (Denmark)

    Hansen, Flemming Yssing; Newton, J. C.; Taub, H.

    1993-01-01

    The effect of molecular steric properties on the melting of quasi-two-dimensional solids is investigated by comparing results of molecular dynamics simulations of the melting of butane and hexane monolayers adsorbed on the basal-plane surface of graphite. These molecules differ only in their length......, being members of the n-alkane series [CH3(CH2)n−2CH3] where n=4 for butane and n=6 for hexane. The simulations employ a skeletal model, which does not include the hydrogen atoms explicitly, to represent the intermolecular and molecule–substrate interactions. Nearest-neighbor intramolecular bonds...... are fixed in length, but the molecular flexibility is preserved by allowing the bend and dihedral torsion angles to vary. The simulations show a qualitatively different melting behavior for the butane and hexane monolayers consistent with neutron and x-ray scattering experiments. The melting of the low...

  7. Assessment of sodium conductor distribution cable

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-06-01

    The study assesses the barriers and incentives for using sodium conductor distribution cable. The assessment considers environmental, safety, energy conservation, electrical performance and economic factors. Along with all of these factors considered in the assessment, the sodium distribution cable system is compared to the present day alternative - an aluminum conductor system. (TFD)

  8. Doped LZO buffer layers for laminated conductors

    Science.gov (United States)

    Paranthaman, Mariappan Parans [Knoxville, TN; Schoop, Urs [Westborough, MA; Goyal, Amit [Knoxville, TN; Thieme, Cornelis Leo Hans [Westborough, MA; Verebelyi, Darren T [Oxford, MA; Rupich, Martin W [Framingham, MA

    2010-03-23

    A laminated conductor includes a metallic substrate having a surface, a biaxially textured buffer layer supported by the surface of the substrate, the biaxially textured buffer layer comprising LZO and a dopant for mitigating metal diffusion through the LZO, and a biaxially textured conductor layer supported by the biaxially textured buffer layer.

  9. Radiation damages on superionic conductors

    International Nuclear Information System (INIS)

    Awano, T.; Ikezawa, M.; Matsuyama, T.

    1995-01-01

    Irradiation coloration on superionic conductors of MA 4 X 5 (M=K, Rb, NH 4 ; A=Ag, Cu; X=Cl, I) was observed. Five absorption bands were observed at 1.4, 1.8, 2.1, 2.3 and 2.9 eV in RbAg 4 I 5 . In these crystals, stable coloration was observed at lower temperature than in alkali halides. The absorption bands due to electronic centers and hole one were classified from the results of optical breaching and electron or hole doping. Growth rate and induced spectra by irradiation changed drastically at the temperatures just above the superionic phase transition. The growth rate increased drastically also at 40 K. ESR signal of γ-irradiated RbCu 4 Cl 3 I 2 showed that one of the induced defects is a hole trapped by a monovalent copper ion (Cu 2+ ). (author)

  10. Frequency Dependent Losses in Transmission Cable Conductors

    DEFF Research Database (Denmark)

    Olsen, Rasmus Schmidt; Holbøll, Joachim; Guðmundsdóttir, Unnur Stella

    2011-01-01

    , such as thermal conditions in and around the cable, as well as the heat generated in conductors, screens, armours etc., taking into account proximity and skin effects. The work performed and presented in this paper is concerned with an improved determination of the losses generated in the conductor, by means...... of better calculation of the AC resistance of transmission cable conductors, in particular regarding higher frequencies. In this way, also losses under harmonics can be covered. Furthermore, the model is suitable for modelling of transient attenuation in high voltage cables. The AC resistance is calculated...... based on the current density distribution in different conductor designs by means of the Finite Element Method (FEM). The obtained results and methods are compared to available standards (IEC publication 60287-1-1)....

  11. Rail industry job analysis : passenger conductor.

    Science.gov (United States)

    2013-02-01

    This document describes the results of a job analysis that was conducted for the position of railroad Passenger Conductor. Key aspects of the position were identified, including main tasks and knowledge, skills, abilities, and other characteristics (...

  12. Rail industry job analysis : freight conductor.

    Science.gov (United States)

    2013-03-01

    This document describes the results from a job analysis that was conducted for the position of Freight Conductor. Key aspects of the position were identified, including main tasks and knowledge, skills, abilities, and other characteristics (KSAOs) ne...

  13. Insulator-insulator and insulator-conductor transitions in the phase diagram of aluminium trichloride

    Directory of Open Access Journals (Sweden)

    Romina Ruberto

    2009-01-01

    Full Text Available We report a classical computer-simulation study of the phase diagram of AlCl3 in the pressure-temperature (p, T plane, showing (i that melting from a layered crystal structure occurs into a molecular liquid at low (p, T and into a dissociated ionic liquid at high (p, T, and (ii that a broad transition from a molecular insulator to an ionic conductor takes place in the liquid state.

  14. Near omni-conductors and insulators: Alternant hydrocarbons in the SSP model of ballistic conduction

    OpenAIRE

    Fowler, P.W.; Sciriha, I.; Borg, M.; Seville, V.E.; Pickup, B.T.

    2017-01-01

    Within the source-and-sink-potential model, a complete characterisation is obtained for the conduction behaviour of alternant π-conjugated hydrocarbons (conjugated hydrocarbons without odd cycles). In this model, an omni-conductor has a molecular graph that conducts at the Fermi level irrespective of the choice of connection vertices. Likewise, an omni-insulator is a molecular graph that fails to conduct for any choice of connections. We give a comprehensive classification of possible combina...

  15. Properties and applications of perovskite proton conductors

    Directory of Open Access Journals (Sweden)

    Eduardo Caetano Camilo de Souza

    2010-09-01

    Full Text Available A brief overview is given of the main types and principles of solid-state proton conductors with perovskite structure. Their properties are summarized in terms of the defect chemistry, proton transport and chemical stability. A good understanding of these subjects allows the manufacturing of compounds with the desired electrical properties, for application in renewable and sustainable energy devices. A few trends and highlights of the scientific advances are given for some classes of protonic conductors. Recent results and future prospect about these compounds are also evaluated. The high proton conductivity of barium cerate and zirconate based electrolytes lately reported in the literature has taken these compounds to a highlight position among the most studied conductor ceramic materials.

  16. Challenges and status of ITER conductor production

    Science.gov (United States)

    Devred, A.; Backbier, I.; Bessette, D.; Bevillard, G.; Gardner, M.; Jong, C.; Lillaz, F.; Mitchell, N.; Romano, G.; Vostner, A.

    2014-04-01

    Taking the relay of the large Hadron collider (LHC) at CERN, ITER has become the largest project in applied superconductivity. In addition to its technical complexity, ITER is also a management challenge as it relies on an unprecedented collaboration of seven partners, representing more than half of the world population, who provide 90% of the components as in-kind contributions. The ITER magnet system is one of the most sophisticated superconducting magnet systems ever designed, with an enormous stored energy of 51 GJ. It involves six of the ITER partners. The coils are wound from cable-in-conduit conductors (CICCs) made up of superconducting and copper strands assembled into a multistage cable, inserted into a conduit of butt-welded austenitic steel tubes. The conductors for the toroidal field (TF) and central solenoid (CS) coils require about 600 t of Nb3Sn strands while the poloidal field (PF) and correction coil (CC) and busbar conductors need around 275 t of Nb-Ti strands. The required amount of Nb3Sn strands far exceeds pre-existing industrial capacity and has called for a significant worldwide production scale up. The TF conductors are the first ITER components to be mass produced and are more than 50% complete. During its life time, the CS coil will have to sustain several tens of thousands of electromagnetic (EM) cycles to high current and field conditions, way beyond anything a large Nb3Sn coil has ever experienced. Following a comprehensive R&D program, a technical solution has been found for the CS conductor, which ensures stable performance versus EM and thermal cycling. Productions of PF, CC and busbar conductors are also underway. After an introduction to the ITER project and magnet system, we describe the ITER conductor procurements and the quality assurance/quality control programs that have been implemented to ensure production uniformity across numerous suppliers. Then, we provide examples of technical challenges that have been encountered and

  17. Velocity measurement of conductor using electromagnetic induction

    International Nuclear Information System (INIS)

    Kim, Gu Hwa; Kim, Ho Young; Park, Joon Po; Jeong, Hee Tae; Lee, Eui Wan

    2002-01-01

    A basic technology was investigated to measure the speed of conductor by non-contact electromagnetic method. The principle of the velocity sensor was electromagnetic induction. To design electromagnet for velocity sensor, 2D electromagnetic analysis was performed using FEM software. The sensor output was analyzed according to the parameters of velocity sensor, such as the type of magnetizing currents and the lift-off. Output of magnetic sensor was linearly depended on the conductor speed and magnetizing current. To compensate the lift-off changes during measurement of velocity, the other magnetic sensor was put at the pole of electromagnet.

  18. Challenges and status of ITER conductor production

    International Nuclear Information System (INIS)

    Devred, A; Backbier, I; Bessette, D; Bevillard, G; Gardner, M; Jong, C; Lillaz, F; Mitchell, N; Romano, G; Vostner, A

    2014-01-01

    Taking the relay of the large Hadron collider (LHC) at CERN, ITER has become the largest project in applied superconductivity. In addition to its technical complexity, ITER is also a management challenge as it relies on an unprecedented collaboration of seven partners, representing more than half of the world population, who provide 90% of the components as in-kind contributions. The ITER magnet system is one of the most sophisticated superconducting magnet systems ever designed, with an enormous stored energy of 51 GJ. It involves six of the ITER partners. The coils are wound from cable-in-conduit conductors (CICCs) made up of superconducting and copper strands assembled into a multistage cable, inserted into a conduit of butt-welded austenitic steel tubes. The conductors for the toroidal field (TF) and central solenoid (CS) coils require about 600 t of Nb 3 Sn strands while the poloidal field (PF) and correction coil (CC) and busbar conductors need around 275 t of Nb–Ti strands. The required amount of Nb 3 Sn strands far exceeds pre-existing industrial capacity and has called for a significant worldwide production scale up. The TF conductors are the first ITER components to be mass produced and are more than 50% complete. During its life time, the CS coil will have to sustain several tens of thousands of electromagnetic (EM) cycles to high current and field conditions, way beyond anything a large Nb 3 Sn coil has ever experienced. Following a comprehensive R and D program, a technical solution has been found for the CS conductor, which ensures stable performance versus EM and thermal cycling. Productions of PF, CC and busbar conductors are also underway. After an introduction to the ITER project and magnet system, we describe the ITER conductor procurements and the quality assurance/quality control programs that have been implemented to ensure production uniformity across numerous suppliers. Then, we provide examples of technical challenges that have been

  19. Resistive coating for current conductors in cryogenic applications

    International Nuclear Information System (INIS)

    Hirayama, C.; Wagner, G.R.

    1982-01-01

    This invention relates to a resistive or semiconducting coating for use on current conductors in cryogenic applications. This includes copper-clad superconductor wire, copper wire used for stabilizing superconductor magnets, and for hyperconductors. The coating is a film of cuprous sulfide (Cu2S) that has been found not to degrade the properties of the conductors. It is very adherent to the respective conductors and satisfies the mechanical, thermal and electrical requirements of coatings for the conductors

  20. High-temperature superconducting conductors and cables

    International Nuclear Information System (INIS)

    Peterson, D.E.; Maley, M.P.; Boulaevskii, L.; Willis, J.O.; Coulter, J.Y.; Ullmann, J.L.; Cho, Jin; Fleshler, S.

    1996-01-01

    This is the final report of a 3-year LDRD project at LANL. High-temperature superconductivity (HTS) promises more efficient and powerful electrical devices such as motors, generators, and power transmission cables; however this depends on developing HTS conductors that sustain high current densities J c in high magnetic fields at temperatures near liq. N2's bp. Our early work concentrated on Cu oxides but at present, long wire and tape conductors can be best made from BSCCO compounds with high J c at low temperatures, but which are degraded severely at temperatures of interest. This problem is associated with thermally activated motion of magnetic flux lines in BSCCO. Reducing these dc losses at higher temperatures will require a high density of microscopic defects that will pin flux lines and inhibit their motion. Recently it was shown that optimum defects can be produced by small tracks formed by passage of energetic heavy ions. Such defects result when Bi is bombarded with high energy protons. The longer range of protons in matter suggests the possibility of application to tape conductors. AC losses are a major limitation in many applications of superconductivity such as power transmission. The improved pinning of flux lines reduces ac losses, but optimization also involves other factors. Measuring and characterizing these losses with respect to material parameters and conductor design is essential to successful development of ac devices

  1. 33 CFR 183.425 - Conductors: General.

    Science.gov (United States)

    2010-07-01

    ...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Electrical Systems Manufacturer Requirements § 183.425... than 30 inches. (g) This section does not apply to communications systems; electronic navigation... conductors and terminations that are in ignition systems; pigtails of less than seven inches of exposed...

  2. High Temperature Protonic Conductors by Melt Growth

    Science.gov (United States)

    2006-11-21

    A.R. de Arellano-López, A. Sayir. “Microestructura y Comportamiento Plástico de Perovsquitas Conductoras Protónicas de Alta Temperatura ”. Bol. Soc...Conductores Protónicos de Alta Temperatura Crecidos por Fusión de Zona Flotante”. VII Reunión Nacional y VI Conferencia Iberoamericana (Electrocerámica

  3. Reshaping the perfect electrical conductor cylinder arbitrarily

    International Nuclear Information System (INIS)

    Chen Huanyang; Zhang Xiaohe; Luo Xudong; Ma Hongru; Chan Cheting

    2008-01-01

    A general method is proposed to design a cylindrical cloak, concentrator and superscatterer with an arbitrary cross section. The method is demonstrated by the design of a perfect electrical conductor (PEC) reshaper which is able to reshape a PEC cylinder arbitrarily by combining the concept of cloak, concentrator and superscatterer together. Numerical simulations are performed to demonstrate its properties.

  4. Control of Radioactive Lightning-Conductor

    International Nuclear Information System (INIS)

    Esposito, E.

    2004-01-01

    The radioactive lightning-conductor production in Brazil was started in 1970 and after a period of 19 years of commercialization of these devices, the National Nuclear Energy Commission (CNEN), based in studies done in Brazil and abroad, proved that the radioactive lightning-conductor performance wasn't superior to the conventional one, so the use of radioactive source is not justified. Thence, the authorization for its production was suspended and the installation of this type of lightning-conductor was forbidden. The radioactive material that results from the dismount of these devices must be immediately sent to CNEN, for treatment and temporary storage. After this prohibition and its publication in several specialized magazines, CNEN was searched for several institutions, factories, churches, etc, interested in obtaining information about the handling and shipment procedures of radioactive lightning-conductors that are inoperative and that must be sent to CNEN's Institutes, in a correct and secure form. From this moment CNEN technicians realize that the owners of radioactive lightning-conductors didn't have any knowledge and training in radiation protection, neither in equipment to monitoring the radiation. The radioactive material from these sources is, in almost all cases, the radioisotope 241Am which has a maximum activity of an order of 5 mCi (1,85 x 10-2 TBq); as the radiation emitted by 241Am is of alpha type, whose range in the air, is just few centimeters and the gamma rays are of low energy, an irradiation offer small risk. However, there is a contamination risk on someone hands, by the contact with the source. Aiming to attend, in an objective way, the users' interests in obtaining some pertinent technical information about the shipping of radioactive lightning-conductor that is inoperative or is being replaced and also to optimize its receipt in CNEN's Institutes, because there still has a great number of these lightning-conductors installed and still

  5. Specifications for conductors and proposed conductor configurations: Milestone M5.3

    CERN Document Server

    Bordini, Bernardo; Dhallé, Marc

    2018-01-01

    This document summarises the specifications of a superconductor suitable to be used in a particle accelerator dipole magnet that can reach a field of 16 Tesla during regular operation. The document reports also on the conductor configuration. These specifications set the performance targets for industrial production requirements at large scale. The document motivates the specifications on one hand by taking a particular magnet baseline design as starting point and by considering the results of various conductor test campaigns carried out at partner institutes.

  6. Low ac loss geometries in YBCO coated conductors and impact on conductor stability

    Energy Technology Data Exchange (ETDEWEB)

    Duckworth, Robert C [ORNL; List III, Frederick Alyious [ORNL; Paranthaman, Mariappan Parans [ORNL; Rupich, M. W. [American Superconductor Corporation, Westborough, MA; Zhang, W. [American Superconductor Corporation, Westborough, MA; Xie, Y. Y. [SuperPower Incorporated, Schenectady, New York; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York

    2007-01-01

    Reduction of ac losses in applied ac fields can be accomplished through either the creation of filaments and bridging in YBCO coated conductors or an assembly of narrow width YBCO tapes. The ac losses for each of these geometries were measured at 77 K in perpendicular ac fields up to 100 mT. While ac loss reduction was achieved with YBCO filaments created through laser scribing and inkjet deposition, the assembly of stacked YBCO conductor provides an alternative method of ac loss reduction. When compared to a 4-mm wide YBCO coated conductor with a critical current of 60 A, the ac loss in a stack of 2-mm wide YBCO coated conductors with a similar total critical current was reduced. While the reduction in ac loss in a 2-mm wide stack coincided with the reduction in the engineering current density of the conductor, further reduction of ac loss was obtained through the splicing of the 2-mm wide tapes with low resistance solders. To better determine the practicality of these methods from a stability point of view, a numerical analysis was carried out to determine the influence of bridging and splicing on stability of a YBCO coated conductor for both liquid nitrogen-cooled and conduction cooled geometries.

  7. Structural transitions in superionic conductors

    Energy Technology Data Exchange (ETDEWEB)

    Parrinello, M.; Rahman, A.; Vashishta, P.

    1983-04-04

    The ..cap alpha..arrow-right-left..beta.. phase transition in AgI is studied with use of the new molecular-dynamics technique which allows for a dynamical variation of the shape and size of the cell. In the present model, upon heating of ..beta..-AgI, the iodine ions undergo a hcp..-->..bcc transformation and silver ions become mobile, whereas the reverse transformation is observed on cooling of ..cap alpha..-AgI. The calculated ..cap alpha..arrow-right-left..beta.. transition temperature and structural and dynamical properties are in good agreement with experiments.

  8. High current density aluminum stabilized conductor concepts for space applications

    International Nuclear Information System (INIS)

    Huang, X.; Eyssa, Y.M.; Hilal, M.A.

    1989-01-01

    Lightweight conductors are needed for space magnets to achieve values of E/M (energy stored per unit mass) comparable to the or higher than advanced batteries. High purity aluminum stabilized NbTi composite conductors cooled by 1.8 K helium can provide a winding current density up to 15 kA/cm/sup 2/ at fields up to 10 tesla. The conductors are edge cooled with enough surface area to provide recovery following a normalizing disturbance. The conductors are designed so that current diffusion time in the high purity aluminum is smaller than thermal diffusion time in helium. Conductor design, stability and current diffusion are considered in detail

  9. Near omni-conductors and insulators: Alternant hydrocarbons in the SSP model of ballistic conduction

    Science.gov (United States)

    Fowler, Patrick W.; Sciriha, Irene; Borg, Martha; Seville, Victoria E.; Pickup, Barry T.

    2017-10-01

    Within the source-and-sink-potential model, a complete characterisation is obtained for the conduction behaviour of alternant π-conjugated hydrocarbons (conjugated hydrocarbons without odd cycles). In this model, an omni-conductor has a molecular graph that conducts at the Fermi level irrespective of the choice of connection vertices. Likewise, an omni-insulator is a molecular graph that fails to conduct for any choice of connections. We give a comprehensive classification of possible combinations of omni-conducting and omni-insulating behaviour for molecular graphs, ranked by nullity (number of non-bonding orbitals). Alternant hydrocarbons are those that have bipartite molecular graphs; they cannot be full omni-conductors or full omni-insulators but may conduct or insulate within well-defined subsets of vertices (unsaturated carbon centres). This leads to the definition of "near omni-conductors" and "near omni-insulators." Of 81 conceivable classes of conduction behaviour for alternants, only 14 are realisable. Of these, nine are realised by more than one chemical graph. For example, conduction of all Kekulean benzenoids (nanographenes) is described by just two classes. In particular, the catafused benzenoids (benzenoids in which no carbon atom belongs to three hexagons) conduct when connected to leads via one starred and one unstarred atom, and otherwise insulate, corresponding to conduction type CII in the near-omni classification scheme.

  10. Benchmarking organic mixed conductors for transistors

    KAUST Repository

    Inal, Sahika; Malliaras, George G.; Rivnay, Jonathan

    2017-01-01

    Organic mixed conductors have garnered significant attention in applications from bioelectronics to energy storage/generation. Their implementation in organic transistors has led to enhanced biosensing, neuromorphic function, and specialized circuits. While a narrow class of conducting polymers continues to excel in these new applications, materials design efforts have accelerated as researchers target new functionality, processability, and improved performance/stability. Materials for organic electrochemical transistors (OECTs) require both efficient electronic transport and facile ion injection in order to sustain high capacity. In this work, we show that the product of the electronic mobility and volumetric charge storage capacity (µC*) is the materials/system figure of merit; we use this framework to benchmark and compare the steady-state OECT performance of ten previously reported materials. This product can be independently verified and decoupled to guide materials design and processing. OECTs can therefore be used as a tool for understanding and designing new organic mixed conductors.

  11. Benchmarking organic mixed conductors for transistors

    KAUST Repository

    Inal, Sahika

    2017-11-20

    Organic mixed conductors have garnered significant attention in applications from bioelectronics to energy storage/generation. Their implementation in organic transistors has led to enhanced biosensing, neuromorphic function, and specialized circuits. While a narrow class of conducting polymers continues to excel in these new applications, materials design efforts have accelerated as researchers target new functionality, processability, and improved performance/stability. Materials for organic electrochemical transistors (OECTs) require both efficient electronic transport and facile ion injection in order to sustain high capacity. In this work, we show that the product of the electronic mobility and volumetric charge storage capacity (µC*) is the materials/system figure of merit; we use this framework to benchmark and compare the steady-state OECT performance of ten previously reported materials. This product can be independently verified and decoupled to guide materials design and processing. OECTs can therefore be used as a tool for understanding and designing new organic mixed conductors.

  12. Superconducting homopolar motor and conductor development

    Science.gov (United States)

    Gubser, Donald U.

    1996-10-01

    The U.S. Navy has been developing superconducting homopolar motors for ship applications since 1969; a successful at-sea demonstration of the first motor, using NbTi wire for the magnet, was achieved in the early 1980s. Recently, this same motor was used as a test bed to demonstrate progress in high-critical-temperature superconducting magnet technology using bismuth-strontium- calcium-copper-oxide (BSCCO) compounds. In the fall of 1995, this motor achieved a performance of 124 kW operating at a temperature of 4.2 K and 91 kW while operating at 28 K. Future tests are scheduled using new magnets with conductors of both the 2223 and the 2212 BSCCO phases. This article describes the advantages of superconducting propulsion and recent progress in the development of BSCCO conductors for use in Navy power systems.

  13. Films of Carbon Nanomaterials for Transparent Conductors

    Directory of Open Access Journals (Sweden)

    Jun Wei

    2013-05-01

    Full Text Available The demand for transparent conductors is expected to grow rapidly as electronic devices, such as touch screens, displays, solid state lighting and photovoltaics become ubiquitous in our lives. Doped metal oxides, especially indium tin oxide, are the commonly used materials for transparent conductors. As there are some drawbacks to this class of materials, exploration of alternative materials has been conducted. There is an interest in films of carbon nanomaterials such as, carbon nanotubes and graphene as they exhibit outstanding properties. This article reviews the synthesis and assembly of these films and their post-treatment. These processes determine the film performance and understanding of this platform will be useful for future work to improve the film performance.

  14. Local noise in a diffusive conductor

    Science.gov (United States)

    Tikhonov, E. S.; Shovkun, D. V.; Ercolani, D.; Rossella, F.; Rocci, M.; Sorba, L.; Roddaro, S.; Khrapai, V. S.

    2016-07-01

    The control and measurement of local non-equilibrium configurations is of utmost importance in applications on energy harvesting, thermoelectrics and heat management in nano-electronics. This challenging task can be achieved with the help of various local probes, prominent examples including superconducting or quantum dot based tunnel junctions, classical and quantum resistors, and Raman thermography. Beyond time-averaged properties, valuable information can also be gained from spontaneous fluctuations of current (noise). From these perspective, however, a fundamental constraint is set by current conservation, which makes noise a characteristic of the whole conductor, rather than some part of it. Here we demonstrate how to remove this obstacle and pick up a local noise temperature of a current biased diffusive conductor with the help of a miniature noise probe. This approach is virtually noninvasive for the electronic energy distributions and extends primary local measurements towards strongly non-equilibrium regimes.

  15. AA, inner conductor of a magnetic horn

    CERN Multimedia

    CERN PhotoLab

    1981-01-01

    At the start-up of the AA and during its initial operation, magnetic horns focused the antiprotons emanating from the production target. These "current-sheet lenses" had a thin inner conductor (for minimum absorption of antiprotons), machined from aluminium to wall thicknesses of 0.7 or 1 mm. The half-sine pulses rose to 150 kA in 8 microsec. The angular acceptance was 50 mrad.

  16. Hall effect in organic layered conductors

    Directory of Open Access Journals (Sweden)

    R.A.Hasan

    2006-01-01

    Full Text Available The Hall effect in organic layered conductors with a multisheeted Fermi surfaces was considered. It is shown that the experimental study of Hall effect and magnetoresistance anisotropy at different orientations of current and a quantizing magnetic field relative to the layers makes it possible to determine the contribution of various charge carriers groups to the conductivity, and to find out the character of Fermi surface anisotropy in the plane of layers.

  17. Testing of the 3M Company Composite Conductor

    Energy Technology Data Exchange (ETDEWEB)

    Stovall, John P [ORNL; Rizy, D Tom [ORNL; Kisner, Roger A [ORNL

    2010-10-01

    The 3M Company has developed a high-temperature low-sag conductor referred to as Aluminum-Conductor Composite-Reinforced or ACCR. The conductor uses an aluminum metal matrix material to replace the steel in conventional conductors. The objective of this work is to accelerate the commercial acceptance by electric utilities of this new conductor design by testing four representative conductor classes in controlled conditions. A unique facility called the Powerline Conductor Accelerated Testing (PCAT) Facility was built at ORNL for testing overhead conductors. The PCAT has been uniquely designed for testing overhead bare transmission line conductors at high currents and temperatures after they have been installed and tensioned to the manufacturer's specifications. The ability to operate a transmission line conductor in this manner does not exist elsewhere in the United States. Four classes of ACCR cable designed by the 3M Company have been successfully test at ORNL small, medium, large and small/compact. Based on these and other manufacturer tests, the 3M Company has successfully introduced the ACCR into the commercial market and has completed over twenty installations for utility companies.

  18. Mechanical test of the model coil wound with large conductor

    International Nuclear Information System (INIS)

    Hiue, Hisaaki; Sugimoto, Makoto; Nakajima, Hideo; Yasukawa, Yukio; Yoshida, Kiyoshi; Hasegawa, Mitsuru; Ito, Ikuo; Konno, Masayuki.

    1992-09-01

    The high rigidity and strength of the winding pack are required to realize the large superconducting magnet for the fusion reactor. This paper describes mechanical tests concerning the rigidity of the winding pack. Samples were prepared to evaluate the adhesive strength between conductors and insulators. Epoxy and Bismaleimide-Triazine resin (BT resin) were used as the conductor insulator. The stainless steel (SS) 304 bars, whose surface was treated mechanically and chemically, was applied to the modeled conductor. The model coil was would with the model conductors covered with the insulator by grand insulator. A winding model combining 3 x 3 conductors was produced for measuring shearing rigidity. The sample was loaded with pure shearing force at the LN 2 temperature. The bar winding sample, by 8 x 6 conductors, was measured the bending rigidity. These three point bending tests were carried out at room temperature. The pancake winding sample was loaded with compressive forces to measure compressive rigidity of winding. (author)

  19. Apparatus to examine pulsed parallel field losses in large conductors

    International Nuclear Information System (INIS)

    Miller, J.R.; Shen, S.S.

    1977-01-01

    Conductors in tokamak toroidal field coils will be exposed to pulsed fields both parallel and perpendicular to the current direction. These conductors will likely be quite high capacity (10 to 20 kA) and therefore probably will be built up out of smaller units. We have previously published measurements of losses in conductors exposed to a pulsed parallel field, but those experiments necessarily used monolithic conductors of relatively small cross section because the pulse coil, a torus that surrounded the test conductor, was itself small. Here we describe an apparatus that is conceptually similar but has been scaled up to accept conductors of much larger cross section and current capacity. The apparatus consists basically of a superconducting torus that contains a movable spool to allow test samples to be wound inside without unwinding the torus. Details of apparatus design and capabilities are described and preliminary results from tests of the apparatus and from loss measurements using it are reported

  20. Test of ITER conductors in SULTAN: An update

    International Nuclear Information System (INIS)

    Bruzzone, Pierluigi; Stepanov, Boris; Wesche, Rainer; Herzog, Robert; Calzolaio, Ciro; Vogel, Martin

    2011-01-01

    The ITER Toroidal Field (TF) conductor qualification phase has been carried out by testing short sample prototype conductors in the SULTAN test facility. This phase, started in 2007, has been substantially completed after minor adjustment of the conductor specification and test procedures. All the parties involved in the TF conductor procurement passed the qualification phase. Starting 2010, the samples for TF process qualification phase are tested in SULTAN. A summary of the results for all the ITER Qualification samples and an updated statistics are presented for the V-I and V-T characteristics of the cable-in-conduit conductors (CICC), including Nb 3 Sn and NbTi samples assembled with either a 'bottom joint' or a 'U-bend'. The technical improvements of the test facility are reported, including the enhanced cyclic loading rate and the calibration of the current meter. An outlook of the ITER conductor tests in the coming years is also presented.

  1. Electronic and Ionic Conductors from Ordered Microporous Materials

    Energy Technology Data Exchange (ETDEWEB)

    Dincă, Mircea [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2017-10-30

    The proposed work aimed to establish metal-organic frameworks (MOFs) as new classes of high-surface area microporous electronic and ionic conductors. MOFs are crystalline materials with pore sizes ranging from 0.2 to ~ 2 nm (or larger for the latter) defined by inorganic or organic building blocks connected by rigid organic linkers. Myriad applications have been found or proposed for these materials, yet those that require electron transport or conductivity in combination with permanent porosity still lag behind because the vast majority of known frameworks are electrical insulators. Prior to our proposal and subsequent work, there were virtually no studies exploring the possibility of electronic delocalization in these materials. Therefore, our primary goal was to understand and control, at a fundamental level, the electron and ion transport properties of this class of materials, with no specific application proposed, although myriad applications could be envisioned for high surface area conductors. Our goals directly addressed one of the DOE-identified Grand Challenges for Basic Energy Sciences: designing perfect atom- and energy-efficient syntheses of revolutionary new forms of matter with tailored properties. Indeed, the proposed work is entirely synthetic in nature; owing to the molecular nature of the building blocks in MOFs, there is the possibility of unprecedented control over the structure and properties of solid crystalline matter. The goals also tangentially addressed the Grand Challenge of controlling materials processes at the level of electrons: the scope of our program is to create new materials where charges (electrons and/or ions) move according to predefined pathways.

  2. Hearing status among Norwegian train drivers and train conductors

    OpenAIRE

    Lie, A.; Skogstad, M.; Johnsen, T. S.; Engdahl, B.; Tambs, K.

    2013-01-01

    Background There is a general perception that train drivers and conductors may be at increased risk of developing noise-induced hearing loss. Aims To study job-related hearing loss among train drivers and train conductors. Methods Audiograms from train drivers and train conductors were obtained from the medical records of the occupational health service of the major Norwegian railway company. The results were compared with audiograms from an internal control group of railway workers and an ex...

  3. Fabrication of built-up conductors for large pulsed coils

    International Nuclear Information System (INIS)

    Henke, M.D.; Schermer, R.I.

    1979-01-01

    The development work was performed to provide a low-loss, cryostable conductor capable of carrying 5 kA at 3 T for a 30-MJ coil cycled at 0.35 Hz. Much of the work is relevant to conductor development for other pulsed coils, such as a tokamak induction heating coil. As part of the development process, various conductor configurations were subjected to ac loss measurements, stability tests, electrical resistance measurements, and mechanical load-bearing and mechanical fatigue tests. The result is a conductor that appears to satisfy the design criteria with a considerable safety margin

  4. Development of YBCO tape conductor fabrication technology

    Energy Technology Data Exchange (ETDEWEB)

    Hong, G W; Kim, C J; Lee, H G. and others

    2001-08-01

    Superconductor when fabricated into wire shape is applied for developing electric power transmission cable, transformer, generator and SMES. Such superconducting power devices are capable of maximizing the efficiency of electricity and are anticipated to contribute for solving the energy problem of humankind. Furthermore the high temperature oxide superconductor developed in late 1980s is superconducting above boiling temperature of liquid nitrogen temperature has strong potential to realize superconducting power device and a lot of researches are being done in this field. Superconducting wire is the most important core material for developing superconducting power device and thermo-mechanical powder in tube process was developed to fabricated Ag/Bi-2223 conductor in long length having high critical current carrying capacity. Several companies fabricate and sell Ag/Bi-2223 superconducting wire longer than km length and used for developed electrical power device. But because of its inherent property of sharp decrease in current carrying capacity when applying high magnetic field, the application of Bi-2223 sire is limited as low as 20 K when the power device is in operating under high magnetic field. The YBCO tape conductor has the advantages of maintaining high critical current applying high magnetic field and can be used to most of the power device without special limitation. The metal substrate having good crystallographic texture and deposition technique which can deposit the good quality superconducting thin film continuously in large area are need to fabricate coated conductor, and this technique can be applied to develop the superconducting current limiter or magnetic field shielding device. A superconducting wire for using in high magnetic field is play a critical role in developing maglev, MRI, SMES, transformer, generator and motor and the continuous film deposition technique can be applied in other industry very much.

  5. AA, Inner Conductor of Magnetic Horn

    CERN Multimedia

    CERN PhotoLab

    1979-01-01

    Antiprotons emerging at large angles from the production target (hit by an intense 26 GeV proton beam from the PS), were focused into the acceptance of the injection line of the AA by means of a "magnetic horn" (current-sheet lens). Here we see an early protype of the horn's inner conductor, machined from solid aluminium to a thickness of less than 1 mm. The 1st version had to withstand pulses of 150 kA, 15 us long, every 2.4 s. See 8801040 for a later version.

  6. Flux pinning characteristics of YBCO coated conductor

    International Nuclear Information System (INIS)

    Matsushita, T.; Watanabe, T.; Fukumoto, Y.; Yamauchi, K.; Kiuchi, M.; Otabe, E.S.; Kiss, T.; Watanabe, T.; Miyata, S.; Ibi, A.; Muroga, T.; Yamada, Y.; Shiohara, Y.

    2005-01-01

    Flux pinning properties of PLD-processed YBCO coated conductors deposited on IBAD substrate are investigated. The thickness of YBCO layer is changed in the range of 0.27-1.0 μm. The thickness dependence of critical current density, n-value and irreversibility field are measured in a wide range of magnetic field. The results are compared with the theoretical flux creep-flow model. It is found that these pinning properties are strongly influenced by the thickness as well as the pinning strength. Optimum condition for high field application of this superconductor is discussed

  7. Relative stiffness of flat conductor cables

    Science.gov (United States)

    Hankins, J. D.

    1976-01-01

    The measurement of the bending moment required to obtain a given deflection in short lengths of flat conductor cable (FCC) is presented in this report. Experimental data were taken on 10 different samples of FCC and normalized to express all bending moments (relative stiffness factor) in terms of a cable 5.1 cm (2.0 in.) in width. Data are presented in tabular and graphical form for the covenience of designers who may be interested in finding torques exerted on critical components by short lengths of FCC.

  8. Assessment of conductor degradation in the ITER CS insert coil and implications for the ITER conductors

    Science.gov (United States)

    Mitchell, N.

    2007-01-01

    Nb3Sn cable in conduit-type conductors were expected to provide an efficient way of achieving large conductor currents at high field (up to 13 T) combined with good stability to electromagnetic disturbances due to the extensive helium contact area with the strands. Although ITER model coils successfully reached their design performance (Kato et al 2001 Fusion Eng. Des. 56/57 59-70), initial indications (Mitchell 2003 Fusion Eng. Des. 66-68 971-94) that there were unexplained performance shortfalls have been confirmed. Recent conductor tests (Pasztor et al 2004 IEEE Trans. Appl. Supercond. 14 1527-30) and modelling work (Mitchell 2005 Supercond. Sci. Technol. 18 396-404) suggest that the shortfalls are due to a combination of strand bending and filament fracture under the transverse magnetic loads. Using the new model, the extensive database from the ITER CS insert coil has been reassessed. A parametric fit based on a loss of filament area and n (the exponent of the power-law fit to the electric field) combined with a more rigorous consideration of the conductor field gradient has enabled the coil behaviour to be explained much more consistently than in earlier assessments, now fitting the Nb3Sn strain scaling laws when used with measurements of the conductor operating strain, including conditions when the insert coil current (and hence operating strain) were reversed. The coil superconducting performance also shows a fatigue-type behaviour consistent with recent measurements on conductor samples (Martovetsky et al 2005 IEEE Trans. Appl. Supercond. 15 1367-70). The ITER conductor design has already been modified compared to the CS insert, to increase the margin and provide increased resistance to the degradation, by using a steel jacket to provide thermal pre-compression to reduce tensile strain levels, reducing the void fraction from 36% to 33% and increasing the non-copper material by 25%. Test results are not yet available for the new design and performance

  9. Printable elastic conductors by in situ formation of silver nanoparticles from silver flakes

    Science.gov (United States)

    Matsuhisa, Naoji; Inoue, Daishi; Zalar, Peter; Jin, Hanbit; Matsuba, Yorishige; Itoh, Akira; Yokota, Tomoyuki; Hashizume, Daisuke; Someya, Takao

    2017-08-01

    Printable elastic conductors promise large-area stretchable sensor/actuator networks for healthcare, wearables and robotics. Elastomers with metal nanoparticles are one of the best approaches to achieve high performance, but large-area utilization is limited by difficulties in their processability. Here we report a printable elastic conductor containing Ag nanoparticles that are formed in situ, solely by mixing micrometre-sized Ag flakes, fluorine rubbers, and surfactant. Our printable elastic composites exhibit conductivity higher than 4,000 S cm-1 (highest value: 6,168 S cm-1) at 0% strain, and 935 S cm-1 when stretched up to 400%. Ag nanoparticle formation is influenced by the surfactant, heating processes, and elastomer molecular weight, resulting in a drastic improvement of conductivity. Fully printed sensor networks for stretchable robots are demonstrated, sensing pressure and temperature accurately, even when stretched over 250%.

  10. A primary exploration to quasi-two-dimensional rare-earth ferromagnetic particles: holmium-doped MoS2 sheet as room-temperature magnetic semiconductor

    Science.gov (United States)

    Chen, Xi; Lin, Zheng-Zhe

    2018-05-01

    Recently, two-dimensional materials and nanoparticles with robust ferromagnetism are even of great interest to explore basic physics in nanoscale spintronics. More importantly, room-temperature magnetic semiconducting materials with high Curie temperature is essential for developing next-generation spintronic and quantum computing devices. Here, we develop a theoretical model on the basis of density functional theory calculations and the Ruderman-Kittel-Kasuya-Yoshida theory to predict the thermal stability of two-dimensional magnetic materials. Compared with other rare-earth (dysprosium (Dy) and erbium (Er)) and 3 d (copper (Cu)) impurities, holmium-doped (Ho-doped) single-layer 1H-MoS2 is proposed as promising semiconductor with robust magnetism. The calculations at the level of hybrid HSE06 functional predict a Curie temperature much higher than room temperature. Ho-doped MoS2 sheet possesses fully spin-polarized valence and conduction bands, which is a prerequisite for flexible spintronic applications.

  11. Spin excitations in the quasi-two-dimensional charge-ordered insulator α -(BEDT-TTF ) 2I3 probed via 13C NMR

    Science.gov (United States)

    Ishikawa, Kyohei; Hirata, Michihiro; Liu, Dong; Miyagawa, Kazuya; Tamura, Masafumi; Kanoda, Kazushi

    2016-08-01

    The spin excitations from the nonmagnetic charge-ordered insulating state of α -(BEDT-TTF ) 2I3 at ambient pressure have been investigated by probing the static and low-frequency dynamic spin susceptibilities via site-selective nuclear magnetic resonance at 13C sites. The site-dependent values of the shift and the spin-lattice relaxation rate 1 /T1 below the charge-ordering transition temperature (TCO≈135 K ) demonstrate a spin density imbalance in the unit cell, in accord with the charge-density ratio reported earlier. The shift and 1 /T1 show activated temperature dependence with a static (shift) gap ΔS≈47 -52 meV and a dynamic (1 /T1 ) gap ΔR≈40 meV . The sizes of the gaps are well described in terms of a localized spin model, where spin-1/2 antiferromagnetic dimer chains are weakly coupled with each other.

  12. Search for a nematic phase in the quasi-two-dimensional antiferromagnet CuCrO2 by NMR in an electric field

    Science.gov (United States)

    Sakhratov, Yu. A.; Kweon, J. J.; Choi, E. S.; Zhou, H. D.; Svistov, L. E.; Reyes, A. P.

    2018-03-01

    The magnetic phase diagram of CuCrO2 was studied with an alternative method of simultaneous Cu NMR and electric polarization techniques with the primary goal of demonstrating that, regardless of cooling history of the sample, the magnetic phase with specific helmet-shaped NMR spectra associated with interplanar disorder possesses electric polarization. Our result unequivocally confirms the assumption of Sakhratov et al. [Phys. Rev. B 94, 094410 (2016), 10.1103/PhysRevB.94.094410] that the high-field low-temperature phase is in fact a three-dimensional (3D) polar phase characterized by a 3D magnetic order with tensor order parameter. In comparison with the results obtained in pulsed fields, a modified phase diagram is introduced defining the upper boundary of the first-order transition from the 3D spiral to the 3D polar phase.

  13. The Atchafalaya River Delta. Report 5. The Atchafalaya River Delta Quasi-Two-Dimensional Model of Delta Growth and Impacts on River Stages

    Science.gov (United States)

    1988-12-01

    report are not to be used for advertising , publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or...from van Beek et al. (1979). This comparison shows very good agreement between MCM and prototype flow distribution. 71 100% SIMM ESPORT FLOW MILE 55

  14. Coherent optical nonlinearities and phase relaxation of quasi-three-dimensional and quasi-two-dimensional excitons in ZnSxSe1 - x/ZnSe structures

    DEFF Research Database (Denmark)

    Wagner, Hans Peter; Schätz, A.; Maier, R.

    1997-01-01

    We investigate the dephasing of heavy-hole excitons in different free-standing ZnSxSe1-x/ZnSe layer structures by spectrally resolved transient four-wave mixing. ZnSe layers of 80, 8, and 4 nm thickness with ternary barriers are studied, representing the crossover from quasi-three-dimensional to ...

  15. Gigantic magnetoelectric effect caused by magnetic-field-induced canted antiferromagnetic-paramagnetic transition in quasi-two-dimensional Ca2CoSi2O7 crystal

    Science.gov (United States)

    Akaki, M.; Tozawa, J.; Akahoshi, D.; Kuwahara, H.

    2009-05-01

    We have investigated the magnetic and dielectric properties of Ca2CoSi2O7 crystal. The dielectricity and magnetism of Ca2CoSi2O7 are strongly coupled below a canted antiferromagnetic transition temperature (TN). Magnetic fields induce electric polarization below TN. Interestingly, the magnetic-field-induced electric polarization is detected even without poling electric fields. Below TN, a canted antiferromagnetic-paramagnetic transition is induced by magnetic fields. The large magnetocapacitance is observed around TN. The origin of the large magnetocapacitance is due to the magnetic-field-induced the canted antiferromagnetic-paramagnetic transition.

  16. VAMAS Nb3Sn test conductor

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    A bronze-process Nb 3 Sn conductor was measured as part of the second VAMAS (Versailles Project on Advanced Materials and Standards) international critical-current round robin. The conductor specifications are given in Table 15. The critical current was measured as a function of magnetic field and axial tensile strain. The measured data are presented in Table 16 and in Figs. 23 and 24. The I c and J c values are based on an electric field criterion (E c ) of 1 μV/cm. In the first VAMAS round robin tests, differences in the test specimens' axial strain, caused by variations in the thermal contraction of different test fixtures, was a major source of interlaboratory variation in the critical-current data. Consequently, electromechanical characterization of the test specimen is important for data interpretation and error analysis. In the second round robin, the test apparatus and procedure were more rigidly specified. This increased experimental control reduced the critical-current variation by a factor of 3.5. The results of our measurements will be published in the final VAMAS report

  17. Maximum permissible voltage of YBCO coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z. [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Hong, Z., E-mail: zhiyong.hong@sjtu.edu.cn [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Wang, D.; Zhou, H.; Shen, X.; Shen, C. [Qingpu Power Supply Company, State Grid Shanghai Municipal Electric Power Company, Shanghai (China)

    2014-06-15

    Highlights: • We examine three kinds of tapes’ maximum permissible voltage. • We examine the relationship between quenching duration and maximum permissible voltage. • Continuous I{sub c} degradations under repetitive quenching where tapes reaching maximum permissible voltage. • The relationship between maximum permissible voltage and resistance, temperature. - Abstract: Superconducting fault current limiter (SFCL) could reduce short circuit currents in electrical power system. One of the most important thing in developing SFCL is to find out the maximum permissible voltage of each limiting element. The maximum permissible voltage is defined as the maximum voltage per unit length at which the YBCO coated conductors (CC) do not suffer from critical current (I{sub c}) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the I{sub c} degradation or burnout happens. YBCO coated conductors test in the experiment are from American superconductor (AMSC) and Shanghai Jiao Tong University (SJTU). Along with the quenching duration increasing, the maximum permissible voltage of CC decreases. When quenching duration is 100 ms, the maximum permissible of SJTU CC, 12 mm AMSC CC and 4 mm AMSC CC are 0.72 V/cm, 0.52 V/cm and 1.2 V/cm respectively. Based on the results of samples, the whole length of CCs used in the design of a SFCL can be determined.

  18. Conductor gestures influence evaluations of ensemble performance.

    Science.gov (United States)

    Morrison, Steven J; Price, Harry E; Smedley, Eric M; Meals, Cory D

    2014-01-01

    Previous research has found that listener evaluations of ensemble performances vary depending on the expressivity of the conductor's gestures, even when performances are otherwise identical. It was the purpose of the present study to test whether this effect of visual information was evident in the evaluation of specific aspects of ensemble performance: articulation and dynamics. We constructed a set of 32 music performances that combined auditory and visual information and were designed to feature a high degree of contrast along one of two target characteristics: articulation and dynamics. We paired each of four music excerpts recorded by a chamber ensemble in both a high- and low-contrast condition with video of four conductors demonstrating high- and low-contrast gesture specifically appropriate to either articulation or dynamics. Using one of two equivalent test forms, college music majors and non-majors (N = 285) viewed sixteen 30 s performances and evaluated the quality of the ensemble's articulation, dynamics, technique, and tempo along with overall expressivity. Results showed significantly higher evaluations for performances featuring high rather than low conducting expressivity regardless of the ensemble's performance quality. Evaluations for both articulation and dynamics were strongly and positively correlated with evaluations of overall ensemble expressivity.

  19. Testing of the 3M Company ACCR Conductor

    Energy Technology Data Exchange (ETDEWEB)

    Stovall, J.P.; RIzy, D.T.; Kisner, R.A.; Deve, H.E. (3M Comp.)

    2010-09-15

    The 3M Company has developed a high-temperature low-sag conductor referred to as Aluminum- Conductor Composite-Reinforced or ACCR. The conductor uses an aluminum metal matrix material to replace the steel in conventional conductors so the core has a lower density and higher conductivity. The objective of this work is to accelerate the commercial acceptance by electric utilities of these new conductor designs by testing four representative conductor classes in controlled conditions. Overhead transmission lines use bare aluminum conductor strands wrapped around a steel core strands to transmit electricity. The typical cable is referred to as aluminum-conductor steel-reinforced (ACSR). The outer strands are aluminum, chosen for its conductivity, low weight, and low cost. The center strand is of steel for the strength required to support the weight without stretching the aluminum due to its ductility. The power density of a transmission corridor has been directly increased by increasing the voltage level. Transmission voltages have increased from 115-kV to 765- kV over the past 80 years. In the United States, further increasing the voltage level is not feasible at this point in time, so in order to further increase the power density of a transmission corridor, conductor designs that increase the current carrying capability have been examined. One of the key limiting factors in the design of a transmission line is the conductor sag which determines the clearance of the conductor above ground or underlying structures needed for electrical safety. Increasing the current carrying capability of a conductor increases the joule heating in the conductor which increases the conductor sag. A conductor designed for high-temperature and lowsag operation requires an engineered modification of the conductor materials. To make an advanced cable, the 3M Company solution has been the development of a composite conductor consisting of Nextel ceramic fibers to replace the steel core and

  20. Beyond the Beat: Modelling Intentions in a Virtual Conductor

    NARCIS (Netherlands)

    ter Maat, Mark; Ebbers, Rob M.; Reidsma, Dennis; Nijholt, Antinus

    We describe our research on designing and implementing a Virtual Conductor. That is, a virtual human (embodied agent) that acts like a human conductor in its interaction with a real, human orchestra. We reported previously on a first version that used a digital musical score to lead an orchestra.

  1. Elastically stretchable thin film conductors on an elastomeric substrate

    Science.gov (United States)

    Jones Harris, Joyelle Elizabeth

    Imagine a large, flat screen television that can be rolled into a small cylinder after purchase in the store and then unrolled and mounted onto the wall of a home. The electronic devices within the television must be able to withstand large deformation and tensile strain. Consider a robot that is covered with an electronic skin that simulates human skin. The skin would enable the machine to lift an elderly person with care and sensitivity. The skin will endure repeated deformation with the highest tensile strains being experienced at the robot's joints. These applications and many others will benefit from stretchable electronic circuitry. While several different methods have been employed to create stretchable electronics, all methods use a common tool -- stretchable conductors. Therefore, the goal of this thesis work was to fabricate elastically stretchable conductors that can be used in stretchable electronics. We deposited Au thin films on an elastomeric substrate, and the resulting conductors remained electrically continuous when stretched by 30% and more. We developed photolithographic processes that can be used to pattern elastically stretchable conductors with a 10 mum resolution. We fabricated bi-level stretchable conductors that are separated by an elastomeric insulator and are electrically connected through via holes in the insulator. We applied our bi-level conductors to create a stretchable resistor-inductor-capacitor (RLC) circuit with a tunable resonant frequency. We also used stretchable conductors to measure action potentials in biological samples. This thesis describes the fabrication and application of our elastically stretchable conductors.

  2. 21 CFR 868.1920 - Esophageal stethoscope with electrical conductors.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Esophageal stethoscope with electrical conductors. 868.1920 Section 868.1920 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... stethoscope with electrical conductors. (a) Identification. An esophageal stethoscope with electrical...

  3. The Identification of Conductor-Distinguished Functions of Conducting

    Science.gov (United States)

    Gumm, Alan J.; Battersby, Sharyn L.; Simon, Kathryn L.; Shankles, Andrew E.

    2011-01-01

    The purpose of the present study was to identify whether conductors distinguish functions of conducting similarly to functions implied in previous research. A sample of 84 conductors with a full range of experience levels (M = 9.8) and of a full range of large ensemble types and ensemble age levels rated how much they pay attention to 82…

  4. Overcurrent experiments on HTS tape and cable conductor

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Jensen, Kim Høj; Træholt, Chresten

    2001-01-01

    their critical current. In this light, it is important to investigate the response of HTS tapes and cable conductors to overcurrents several times the critical current. A number of experiments have been performed on HTS tapes and cable conductors, with currents up to 20 times the critical current. During...... overcurrent experiments, the voltage, and the temperature were measured as functions of time in order to investigate the dynamic behavior of the HTS tape and cable conductor. After each experiment, damage to the superconductors was assessed by measuring the critical current. Preliminary results show...... that within seconds an HTS tape (critical current=17 A) heats above room temperature with an overcurrent larger than 140 A. Similar overcurrent experiments showed that a HTS cable conductor could sustain damage with overcurrents exceeding 10 times the critical current of the cable conductor....

  5. LTS and HTS high current conductor development for DEMO

    International Nuclear Information System (INIS)

    Bruzzone, Pierluigi; Sedlak, Kamil; Uglietti, Davide; Bykovsky, Nikolay; Muzzi, Luigi; De Marzi, Gainluca; Celentano, Giuseppe; Della Corte, Antonio; Turtù, Simonetta; Seri, Massimo

    2015-01-01

    Highlights: • Design and R&D for DEMO TF conductors. • Wind&react vs. react&wind options for Nb_3Sn high grade TF conductors. • Progress in the manufacture of short length Nb_3Sn proptotypes. • Design and prototype manufacture for high current HTS cabled conductors. - Abstract: The large size of the magnets for DEMO calls for very large operating current in the forced flow conductor. A plain extrapolation from the superconductors in use for ITER is not adequate to fulfill the technical and cost requirements. The proposed DEMO TF magnets is a graded winding using both Nb_3Sn and NbTi conductors, with operating current of 82 kA @ 13.6 T peak field. Two Nb_3Sn prototypes are being built in 2014 reflecting the two approaches suggested by CRPP (react&wind method) and ENEA (wind&react method). The Nb_3Sn strand (overall 200 kg) has been procured at technical specification similar to ITER. Both the Nb_3Sn strand and the high RRR, Cr plated copper wire (400 kg) have been delivered. The cabling trials are carried out at TRATOS Cavi using equipment relevant for long length production. The completion of the manufacture of the two 20 m long prototypes is expected in the end of 2014 and their test is planned in 2015 at CRPP. In the scope of a long term technology development, high current HTS conductors are built at CRPP and ENEA. A DEMO-class prototype conductor is developed and assembled at CRPP: it is a flat cable composed of 20 twisted stacks of coated conductor tape soldered into copper shells. The 10 kA conductor developed at ENEA consists of stacks of coated conductor tape inserted into a slotted and twisted Al core, with a central cooling channel. Samples have been manufactured in industrial environment and the scalability of the process to long production lengths has been proven.

  6. Irreversible properties of YBCO coated conductors

    International Nuclear Information System (INIS)

    Vostner, A.

    2001-02-01

    Over the past few years substantial efforts were made to optimize the fabrication techniques of various high temperature superconductors for commercial applications. In addition to Bi-2223 tapes, Y-123 coated conductors have the potential for large-scale production and are considered as the second generation of superconducting 'wires' for high current applications. This work reports on magnetic and transport current investigations of Y-123 thick films deposited on either single crystalline substrates by liquid phase epitaxy (LPE) or on metallic substrates by pulsed laser deposition (PLD). At the beginning, a short introduction of the general idea of a coated conductor and of the different production techniques is presented, followed by a description of the different experimental set-ups and the evaluation methods. The main part starts with the results obtained from SQUID magnetometry and ac-susceptibility measurements including the transition temperatures T c , the field dependence of the magnetic critical current densities and the irreversibility lines. In addition, some issues concerning the granular structure and the inter- and intragranular current distribution of the superconducting films are discussed. The investigations by transport currents are focused on the behavior of the application relevant irreversible parameters. These are the angular and the field dependence of the critical transport current densities at 77 and 60 K, as well as the temperature dependence of the irreversibility fields up to 6 T. To gain more insight into the defect structure of the films, neutron irradiation studies were performed on some samples. The introduction of these artificial pinning centers causes large enhancements of the magnetic J c in LPE specimens for the field parallel to the c-axis (H//c) at higher temperatures and magnetic fields. The granular structure of the samples does not change up to the highest neutron fluences. However, the enhancements of the transport J c

  7. Local structure of gallate proton conductors

    Energy Technology Data Exchange (ETDEWEB)

    Giannici, F; Messana, D; Martorana, A [Universita degli Studi di Palermo, Dipartimento di Chimica Inorganica ed Analitica, Viale delle Scienze, I-90128 Palermo (Italy); Longo, A [CNR, Istituto per lo studio dei materiali nanostrutturati, Via Ugo La Malfa 153, I-90146 Palermo (Italy); Sciortino, L, E-mail: sciortino@pa.ismn.cnr.i

    2009-11-15

    Lanthanum barium gallate proton conductors are based on disconnected GaO{sub 4} groups. The insertion of hydroxyls in the LaBaGaO{sub 4} network proceeds through self-doping with Ba{sup 2+}, consequent O{sup 2-} vacancy formation to fulfill charge neutrality. With a structural investigation on self-doped LaBaGaO{sub 4} oxides using synchrotron XRD and EXAFS on the Ga K-edge, we find that: (a) the GaO{sub 4} tetrahedra retain their size throughout the whole series; (b) the GaO{sub 4} tetrahedra rotate as rigid bodies on hydration, leading to the formation of a network of shorter O-O configurations that are stabilized by hydrogen bonds; (c) contraction of the lattice occurs along the a unit cell axis, as a consequence of an overall structural rearrangement of the hydrated solid.

  8. Local structure of gallate proton conductors

    International Nuclear Information System (INIS)

    Giannici, F; Messana, D; Martorana, A; Longo, A; Sciortino, L

    2009-01-01

    Lanthanum barium gallate proton conductors are based on disconnected GaO 4 groups. The insertion of hydroxyls in the LaBaGaO 4 network proceeds through self-doping with Ba 2+ , consequent O 2- vacancy formation to fulfill charge neutrality. With a structural investigation on self-doped LaBaGaO 4 oxides using synchrotron XRD and EXAFS on the Ga K-edge, we find that: (a) the GaO 4 tetrahedra retain their size throughout the whole series; (b) the GaO 4 tetrahedra rotate as rigid bodies on hydration, leading to the formation of a network of shorter O-O configurations that are stabilized by hydrogen bonds; (c) contraction of the lattice occurs along the a unit cell axis, as a consequence of an overall structural rearrangement of the hydrated solid.

  9. Local structure of gallate proton conductors

    Science.gov (United States)

    Giannici, F.; Messana, D.; Longo, A.; Sciortino, L.; Martorana, A.

    2009-11-01

    Lanthanum barium gallate proton conductors are based on disconnected GaO4 groups. The insertion of hydroxyls in the LaBaGaO4 network proceeds through self-doping with Ba2+, consequent O2- vacancy formation to fulfill charge neutrality. With a structural investigation on self-doped LaBaGaO4 oxides using synchrotron XRD and EXAFS on the Ga K-edge, we find that: (a) the GaO4 tetrahedra retain their size throughout the whole series; (b) the GaO4 tetrahedra rotate as rigid bodies on hydration, leading to the formation of a network of shorter O-O configurations that are stabilized by hydrogen bonds; (c) contraction of the lattice occurs along the a unit cell axis, as a consequence of an overall structural rearrangement of the hydrated solid.

  10. [Trophoblast: conductor of the maternal immune tolerance].

    Science.gov (United States)

    Mesdag, V; Salzet, M; Vinatier, D

    2014-11-01

    Pregnancy is a temporary semi-allograft that survives for nine months. The importance of this event for the survival of the species justifies several tolerance mechanisms that are put into place at the beginning of pregnancy, some of which occur even at the time of implantation. The description of these mechanisms underlines the leadership of the trophoblast. The trophoblast is the conductor of the events, protects himself by expressing specific antigens and regulates the environment of the decidua according to the calendar of the events of the pregnancy The trophoblast and the decidual environment attract the effectors of immunity, almost all present in the decidua. The immunological atmosphere of the decidua evolves during the pregnancy modulating the level of activation of the immunological cells and adapting the level of activation to the stage of the pregnancy. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  11. ELECTRODYNAMIC STABILITY COMPUTATIONS FOR FLEXIBLE CONDUCTORS OF THE AERIAL LINES

    Directory of Open Access Journals (Sweden)

    I. I. Sergey

    2015-01-01

    Full Text Available In aerial transmission lines aluminium multiwire conductors are in use. Owing to their flexible design the electrodynamic effect of short circuit currents may lead to intolerable mutual rendezvous and even cross-whipping of the phase conductors. The increasing motion of the conductors caused by effect of the short-circuit electrodynamic force impulse is accompanied by the dynamic load impact affecting the conductors, insulating and supporting constructions of the aerial lines. Intensity of the short-circuit currents electrodynamic impact on the flexible conductors depends on the short circuit current magnitude. For research into electrodynamic endurance of the conductors of the aerial lines located at the vertices of arbitrary triangle with spans of a large length, the authors assume the conductor analytical model in the form of a flexible tensile thread whose mass is distributed evenly lengthwise the conductor. With this analytical model, by the action of the imposed forces the conductor assumes the form conditioned by the diagram of applied external forces, and resists neither bending nor torsion. The initial conditions calculation task reduces to solving the flexible thread statics equations. The law of motion of the conductor marginal points comes out of the conjoint solution of dynamic equations of the conductor and structural components of the areal electric power lines. Based on the proposed algorithm, the researchers of the Chair of the Electric Power Stations of BNTU developed a software program LINEDYS+, which in its characteristics yields to no foreign analogs, e. g. SAMSEF. To calculate the initial conditions they modified a software program computing the flexible conductor mechanics named MR 21. The conductor short-circuit electrodynamic interaction estimation considers structural elements of the areal lines, ice and wind loads, objective parameters of the short circuit. The software programs are accommodated with the simple and

  12. Conduction Mechanisms and Structure of Ionomeric Single-Ion Conductors

    Energy Technology Data Exchange (ETDEWEB)

    Colby, Ralph H. [Pennsylvania State Univ., University Park, PA (United States); Maranas, Janna K. [Pennsylvania State Univ., University Park, PA (United States); Mueller, Karl T. [Pennsylvania State Univ., University Park, PA (United States); Runt, James [Pennsylvania State Univ., University Park, PA (United States); Winey, Karen I. [Univ. of Pennsylvania, Philadelphia, PA (United States)

    2015-03-01

    Our team has designed using DFT (Gaussian) and synthesized low glass transition temperature single-ion conductors that are either polyanions that conduct small cations Li+, Na+, Cs+ or polycations that conduct small anions F-, OH-, Br-. We utilize a wide range of complimentary experimental materials characterization tools to understand ion transport; differential scanning calorimetry, dielectric relaxation spectroscopy, infrared spectroscopy, nuclear magnetic resonance spectroscopy, linear viscoelasticity, X-ray scattering and molecular dynamics simulations. The glass transition temperature Tg needs to be as low as possible to facilitate ion transport, so the nonionic parts of the polymer need to be polar, flexible and have strong solvation interactions with the ions. The lowest Tg we have managed for polyanions conducting Li+ is -60 °C. In contrast, polysiloxanes with PEO side chains and tetrabutylphosphonium cationic side groups have Tg ≈ -75 °C that barely increases with ion content, as anticipated by DFT. A survey of all polyanions in the literature suggests that Tg < -80 °C is needed to achieve the 10-4 S/cm conductivity needed for battery separators.

  13. Enhanced Mixed Electronic-Ionic Conductors through Cation Ordering

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, Allan J. [Univ. of Houston, TX (United States); Morgan, Dane [Univ. of Wisconsin, Madison, WI (United States); Grey, Clare [Stony Brook Univ., NY (United States)

    2014-08-31

    The performance of many energy conversion and storage devices depend on the properties of mixed ionic-electronic conducting (miec) materials. Mixed or ambipolar conductors simultaneously transport ions and electrons and provide the critical interface between chemical and electrical energy in devices such as fuel cells, ion transport membranes, and batteries. Enhancements in storage capacity, reversibility, power density and device lifetime all require new materials and a better understanding of the fundamentals of ambipolar conductivity and surface reactivity.The high temperature properties of the ordered perovksites AA’B2O5+x, where A = rare earth ion, Y and B = Ba, Sr were studied. The work was motivated by the high oxygen transport and surface exchange rates observed for members of this class of mixed ionic and electronic conductors. A combined experimental and computational approach, including structural, electrochemical, and transport characterization and modeling was used. The approach attacks the problem simultaneously at global (e.g., neutron diffraction and impedance spectroscopy), local (e.g., pair distribution function, nuclear magnetic resonance) and molecular (ab initio thermokinetic modeling) length scales. The objectives of the work were to understand how the cation and associated anion order lead to exceptional ionic and electronic transport properties and surface reactivity in AA’B2O5+x perovskites. A variety of compounds were studied by X-ray and neutron diffraction, measurements of thermodynamics and transport and theoretically. These included PrBaCo2O5+x and NdBaCo2O5+x, PrBaCo2-xFexO6- δ (x = 0, 0.5, 1.0, 1.5 and 2) and LnBaCoFeO6- δ (Ln = La, Pr, Nd, Sm, Eu and Gd), Sr3YCo4O10.5, YBaMn2O5+x. A0.5A’0.5BO3 (where A=Y, Sc, La, Ce, Pr, Nd, Pm, Sm; A’= Sr

  14. Recent progress in high-pressure studies on organic conductors

    Directory of Open Access Journals (Sweden)

    Syuma Yasuzuka and Keizo Murata

    2009-01-01

    Full Text Available Recent high-pressure studies of organic conductors and superconductors are reviewed. The discovery of the highest Tc superconductivity among organics under high pressure has triggered the further progress of the high-pressure research. Owing to this finding, various organic conductors with the strong electron correlation were investigated under high pressures. This review includes the pressure techniques using the cubic anvil apparatus, as well as high-pressure studies of the organic conductors up to 10 GPa showing extraordinary temperature and pressure dependent transport phenomena.

  15. Conductor development for the Superconducting Super Collider (SSC)

    International Nuclear Information System (INIS)

    Gregory, E.

    1988-01-01

    This review investigates the developments in fine filamentary materials over the last three years and traces how the relations between the magnet requirements and property improvements have fashioned SSC conductor specifications. The review emphasizes factors that affect filament nonuniformity and the overall quality of the product. The elimination of proximity effect-induced coupling in SCC type conductors, by introducing small percentages of manganese into the copper between the filaments, is discussed. Modification of a Fermi kit has produced materials with improved critical current densities. The possibility of using this approach to make conductors for accelerator magnets is assessed

  16. Electrical circuit modeling of conductors with skin effect

    International Nuclear Information System (INIS)

    Kerst, D.W.; Sprott, J.C.

    1986-01-01

    The electrical impedance of a lossy conductor is a complicated function of time (or frequency) because of the skin effect. By solving the diffusion equation for magnetic fields in conductors of several prototypical shapes, the impedance can be calculated as a function of time for a step function of current. The solution suggests an electrical circuit representation that allows calculation of time-dependent voltages and currents of arbitrary waveforms. A technique using an operational amplifier to determine the current in such a conductor by measuring some external voltage is described. Useful analytical approximations to the results are derived

  17. General relativistic galvano-gravitomagnetic effect in current carrying conductors

    International Nuclear Information System (INIS)

    Ahmedov, B.J.

    1998-11-01

    The analogy between general relativity and electromagnetism suggests that there is a galvano-gravitomagnetic effect, which is the gravitational analogue of the Hall effect. This new effect takes place when a current carrying conductor is placed in a gravitomagnetic field and the conduction electrons moving inside the conductor are deflected transversally with respect to the current flow. In connection with this galvano-gravitomagnetic effect, we explore the possibility of using current carrying conductors for detecting the gravitomagnetic field of the Earth. (author)

  18. The first DC performance test and analysis of CC conductor short sample at ASIPP conductor test facility

    International Nuclear Information System (INIS)

    Shi Yi; Wu Yu; Liu Huajun; Long Feng; Qian Li; Ren Zhibin; Li Shaolei; Liu Bo; Chen Jinglin

    2012-01-01

    Highlights: ► In this study the first DC performance experiments of ITER correction coil conductor short sample have been carried out in ASIPP test facility. ► A CC conductor short sample was fabricated and tested to confirm the capability of this test facility for qualification tests of CC conductors. ► There is no obvious impact of cycling on DC performance measurement. ► Those measured results of current sharing temperature are in agreement with the expected results from strand scaling - Abstract: The first DC performance experiments of ITER correction coil (CC) conductor short sample have been carried out in the conductor test facility of Institute of Plasma Physics, CAS (ASIPP) in January this year. Those experiments aim to investigate the DC performance of ITER CC conductor. The tested conductor short sample is bended as a half circle with the diameter of 270 mm to meet the background magnetic field shape. The half circle part of sample is longer than the final twist pitch. The current sharing temperature (T cs ) in the 3.86 T external magnetic field (B ex ), ≤12 kA could be measured including the critical current (I c ) run. There is no obvious impact of 1000 cycles on DC performance. Those measured T cs results are in agreement with the expected results from strand scaling.

  19. Loss and Inductance Investigation in Superconducting Cable Conductors

    DEFF Research Database (Denmark)

    Olsen, Søren Krüger; Tønnesen, Ole; Træholt, Chresten

    1999-01-01

    An important parameter in the design and optimization of a superconducting cable conductor is the control of the current distribution among single tapes and layers. This distribution is to a large degree determined by inductances, since the resistances are low. The self and mutual inductances...... of transport current and current distribution.This presentation is based on a number of experiments performed on prototype superconducting cable conductors. The critical current (1uV/cm) of the conductor at 77K was 1590 A (cable #1) and 3240 A (cable #2) respectively.At an rms current of 2 kA (50 Hz) the AC......-loss was measured on cable #2 to 0.6W/mxphase. This is, to our knowledge, the lowest AC-loss (at 2kA and 77K) of a high temperature superconducting cable conductor reported so far....

  20. Materials Science of High-Temperature Superconducting Coated Conductor Materials

    National Research Council Canada - National Science Library

    Beasley, M. R

    2007-01-01

    This program was broadly focused on the materials science of high temperature superconducting coated conductors, which are of potential interest for application in electric power systems of interest to the Air Force...

  1. Gravitomagnetic effects in conductor in applied magnetic field

    International Nuclear Information System (INIS)

    Ahmedov, B.J.; Karim, M.

    1999-11-01

    The electromagnetic measurements of general relativistic gravitomagnetic effects which can be performed within a conductor embedded in the space-time of slow rotating gravitational object in the presence of magnetic field are proposed. (author)

  2. High voltage switches having one or more floating conductor layers

    Science.gov (United States)

    Werne, Roger W.; Sampayan, Stephen; Harris, John Richardson

    2015-11-24

    This patent document discloses high voltage switches that include one or more electrically floating conductor layers that are isolated from one another in the dielectric medium between the top and bottom switch electrodes. The presence of the one or more electrically floating conductor layers between the top and bottom switch electrodes allow the dielectric medium between the top and bottom switch electrodes to exhibit a higher breakdown voltage than the breakdown voltage when the one or more electrically floating conductor layers are not present between the top and bottom switch electrodes. This increased breakdown voltage in the presence of one or more electrically floating conductor layers in a dielectric medium enables the switch to supply a higher voltage for various high voltage circuits and electric systems.

  3. Experimental and computational approaches to electrical conductor loading characteristics

    International Nuclear Information System (INIS)

    Vary, M.; Goga, V.; Paulech, J.

    2012-01-01

    This article describes cooling analyses of horizontally arranged bare electric conductor using analytical and numerical methods. Results of these analyses will be compared to the results obtained from experimental measurement. (Authors)

  4. Guanidinium nonaflate as a solid-state proton conductor

    DEFF Research Database (Denmark)

    Chen, Xiaoli; Tang, Haolin; Putzeys, Tristan

    2016-01-01

    Protic organic ionic plastic crystals (POIPCs) are a type of novel solid-state proton conductors. In this work, guanidinium nonaflate ([Gdm-H][NfO]) is reported to be a model POIPC. Its structure-property relationship has been investigated comprehensively. Infrared analysis of [Gdm-H][NfO] and its....... In addition, POIPC-based solid-state proton conductors are also expected to find applications in sensors and other electrochemical devices....

  5. Chaotic Music Generation System Using Music Conductor Gesture

    OpenAIRE

    Chen, Shuai; Maeda, Yoichiro; Takahashi, Yasutake

    2013-01-01

    In the research of interactive music generation, we propose a music generation method, that the computer generates the music, under the recognition of human music conductor's gestures.In this research, the generated music is tuned by the recognized gestures for the parameters of the network of chaotic elements in real time. The music conductor's hand motions are detected by Microsoft Kinect in this system. Music theories are embedded in the algorithm, as a result, the generated music will be ...

  6. Music Conductor Gesture Recognized Interactive Music Generation System

    OpenAIRE

    CHEN, Shuai; MAEDA, Yoichiro; TAKAHASHI, Yasutake

    2012-01-01

    In the research of interactive music generation, we propose a music generation method, that the computer generates the music automatically, and then the music will be arranged under the human music conductor's gestures, before it outputs to us. In this research, the generated music is processed from chaotic sound, which is generated from the network of chaotic elements in realtime. The music conductor's hand motions are detected by Microsoft Kinect in this system. Music theories are embedded ...

  7. Spatial Analysis of Thermal Aging of Overhead Transmission Conductors

    Czech Academy of Sciences Publication Activity Database

    Musílek, P.; Heckenbergerová, Jana; Bhuiyan, M.M.I.

    2012-01-01

    Roč. 27, č. 3 (2012), s. 1196-1204 ISSN 0885-8977 Grant - others:GA AV ČR(CZ) M100300904 Source of funding: V - iné verejné zdroje Keywords : aluminium conductor steel reinforced (ACSR) conductor * hot spot * loss of tensile strength * numerical weather prediction * power transmission lines * thermal aging Subject RIV: JE - Non-nuclear Energetics, Energy Consumption ; Use Impact factor: 1.519, year: 2012

  8. Tilt stability of rotating current rings with passive conductors

    International Nuclear Information System (INIS)

    Zweibel, E.G.; Pomphrey, N.

    1984-12-01

    We study the combined effects of rotation and resistive passive conductors on the stability of a rigid current in an external magnetic field. We present numerical and approximate analytical solutions to the equations of motion, which show that the ring is always tilt unstable on the resistive decay timescale of the conductors, although rotation and eddy currents may stabilize it over short times. Possible applications of our model include spheromaks which rotate or which are encircled by energetic particle rings

  9. Test and evaluation of conductors for superconducting magnetic energy storage

    International Nuclear Information System (INIS)

    Schermer, R.I.; Hassenzahl, W.V.

    1976-01-01

    Pancake coils of a monolithic conductor and several different types of braid and cable, using a variety of insulating tapes and bonding resins were constructed. The coils were tested to quench in self-field at currents up to 2700 A. Results are presented for the training behavior of the various coils as compared to short-sample tests. A conductor composed of several braids or cables in parallel, which will be suitable for the in situ fabrication of large magnets is described

  10. Transport AC losses in YBCO coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Majoros, M [Ohio State University, Columbus, OH 43210 (United States); Ye, L [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Velichko, A V [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Coombs, T A [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Sumption, M D [Ohio State University, Columbus, OH 43210 (United States); Collings, E W [Ohio State University, Columbus, OH 43210 (United States)

    2007-09-15

    Transport AC loss measurements have been made on YBCO-coated conductors prepared on two different substrate templates-RABiTS (rolling-assisted biaxially textured substrate) and IBAD (ion-beam-assisted deposition). RABiTS samples show higher losses compared with the theoretical values obtained from the critical state model, with constant critical current density, at currents lower than the critical current. An origin of this extra AC loss was demonstrated experimentally by comparison of the AC loss of two samples with different I-V curves. Despite a difference in I-V curves and in the critical currents, their measured losses, as well as the normalized losses, were practically the same. However, the functional dependence of the losses was affected by the ferromagnetic substrate. An influence of the presence of a ferromagnetic substrate on transport AC losses in YBCO film was calculated numerically by the finite element method. The presence of a ferromagnetic substrate increases transport AC losses in YBCO films depending on its relative magnetic permeability. The two loss contributions-transport AC loss in YBCO films and ferromagnetic loss in the substrate-cannot be considered as mutually independent.

  11. Electron quantum optics in ballistic chiral conductors

    Energy Technology Data Exchange (ETDEWEB)

    Bocquillon, Erwann; Freulon, Vincent; Parmentier, Francois D.; Berroir, Jean-Marc; Placais, Bernard; Feve, Gwendal [Laboratoire Pierre Aigrain, Ecole Normale Superieure, CNRS (UMR 8551), Universite Pierre et Marie Curie, Universite Paris Diderot, Paris (France); Wahl, Claire; Rech, Jerome; Jonckheere, Thibaut; Martin, Thierry [Aix Marseille Universite, CNRS, CPT, UMR 7332, Marseille (France); Universite de Toulon, CNRS, CPT, UMR 7332, La Garde (France); Grenier, Charles; Ferraro, Dario; Degiovanni, Pascal [Universite de Lyon, Federation de Physique Andre Marie Ampere, CNRS - Laboratoire de Physique de l' Ecole Normale Superieure de Lyon, Lyon (France)

    2014-01-15

    The edge channels of the quantum Hall effect provide one dimensional chiral and ballistic wires along which electrons can be guided in an optics-like setup. Electronic propagation can then be analyzed using concepts and tools derived from optics. After a brief review of electron optics experiments performed using stationary current sources which continuously emit electrons in the conductor, this paper focuses on triggered sources, which can generate on-demand a single particle state. It first outlines the electron optics formalism and its analogies and differences with photon optics and then turns to the presentation of single electron emitters and their characterization through the measurements of the average electrical current and its correlations. This is followed by a discussion of electron quantum optics experiments in the Hanbury-Brown and Twiss geometry where two-particle interferences occur. Finally, Coulomb interactions effects and their influence on single electron states are considered. (copyright 2013 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Electron quantum optics in ballistic chiral conductors

    International Nuclear Information System (INIS)

    Bocquillon, Erwann; Freulon, Vincent; Parmentier, Francois D.; Berroir, Jean-Marc; Placais, Bernard; Feve, Gwendal; Wahl, Claire; Rech, Jerome; Jonckheere, Thibaut; Martin, Thierry; Grenier, Charles; Ferraro, Dario; Degiovanni, Pascal

    2014-01-01

    The edge channels of the quantum Hall effect provide one dimensional chiral and ballistic wires along which electrons can be guided in an optics-like setup. Electronic propagation can then be analyzed using concepts and tools derived from optics. After a brief review of electron optics experiments performed using stationary current sources which continuously emit electrons in the conductor, this paper focuses on triggered sources, which can generate on-demand a single particle state. It first outlines the electron optics formalism and its analogies and differences with photon optics and then turns to the presentation of single electron emitters and their characterization through the measurements of the average electrical current and its correlations. This is followed by a discussion of electron quantum optics experiments in the Hanbury-Brown and Twiss geometry where two-particle interferences occur. Finally, Coulomb interactions effects and their influence on single electron states are considered. (copyright 2013 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Applications of inorganic Ion-conductor

    Energy Technology Data Exchange (ETDEWEB)

    Fujiki, Yoshinori [Science and Technology Agency, Tokyo (Japan)

    1989-03-01

    Physical properties and application of solid electrolyte, particularly of inorganic solid electrolyte, are described. Ion conductors have been widely used not only for electric power application but also for sensors, gas separators, display elements, Coulomb meters, storage elements, etc. The most extensively used pacemakers now employ Li/I{sub 2}(PVP) primary batteries. Thin film lithium secondary battery has a feature of providing comparatively large electric current, with 2.5 V charging, 1.8 V discharging, and 3 mA.cm{sup {minus}2} short circuit current. The capacity of about 4 mAh per 1 cm{sup 2} electrode has been achieved. The most widely used solid electrolyte for the oxygen sensor is the stabilized ZrO{sub 2}. The relation of air/fuel mix proportion with the change in electromotive force is shown. Although solid electrolyte fuel cell is not yet put to practical use, a result of an experiment is introduced. Brief explanations are made on the oxygen pump, electrochromic display elements, Coulomb meter and voltage storage element. 18 refs., 11 figs., 6 tabs.

  14. Conductor gestures influence evaluations of ensemble performance

    Directory of Open Access Journals (Sweden)

    Steven eMorrison

    2014-07-01

    Full Text Available Previous research has found that listener evaluations of ensemble performances vary depending on the expressivity of the conductor’s gestures, even when performances are otherwise identical. It was the purpose of the present study to test whether this effect of visual information was evident in the evaluation of specific aspects of ensemble performance, articulation and dynamics. We constructed a set of 32 music performances that combined auditory and visual information and were designed to feature a high degree of contrast along one of two target characteristics: articulation and dynamics. We paired each of four music excerpts recorded by a chamber ensemble in both a high- and low-contrast condition with video of four conductors demonstrating high- and low-contrast gesture specifically appropriate to either articulation or dynamics. Using one of two equivalent test forms, college music majors and nonmajors (N = 285 viewed sixteen 30-second performances and evaluated the quality of the ensemble’s articulation, dynamics, technique and tempo along with overall expressivity. Results showed significantly higher evaluations for performances featuring high rather than low conducting expressivity regardless of the ensemble’s performance quality. Evaluations for both articulation and dynamics were strongly and positively correlated with evaluations of overall ensemble expressivity.

  15. Low ac loss geometries in YBCO coated conductors

    International Nuclear Information System (INIS)

    Duckworth, R.C.; List, F.A.; Paranthaman, M.P.; Rupich, M.W.; Zhang, W.; Xie, Y.Y.; Selvamanickam, V.

    2007-01-01

    Reduction of ac losses in applied ac fields can be accomplished through either the creation of filaments and bridging in YBCO coated conductors or by an assembly of narrow width YBCO tapes. The ac losses for each of these geometries were measured at 77 K in perpendicular ac fields up to 100 mT. Despite physical isolation of the filaments, coupling losses were still present in the samples when compared to the expected hysteretic loss. In addition to filamentary conductors the assembly of stacked YBCO conductor provides an alternative method of ac loss reduction. When compared to a 4-mm wide YBCO coated conductor with a critical current of 60 A, the ac loss in a stack of 2-mm wide YBCO coated conductors with a similar total critical current was reduced. While the reduction in ac loss in a 2-mm wide stack coincided with the reduction in the engineering current density of the conductor, further reduction of ac loss was obtained through the splicing of the 2-mm wide tapes with low resistance solders

  16. Low ac loss geometries in YBCO coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Duckworth, R.C. [Oak Ridge National Laboratory, One Bethel Valley Road, P.O. Box 2008, MS-6305, Oak Ridge, TN 37831-6305 (United States)], E-mail: duckworthrc@ornl.gov; List, F.A.; Paranthaman, M.P. [Oak Ridge National Laboratory, One Bethel Valley Road, P.O. Box 2008, MS-6305, Oak Ridge, TN 37831-6305 (United States); Rupich, M.W.; Zhang, W. [American Superconductor, Two Technology Drive, Westborough, MA 01581 (United States); Xie, Y.Y.; Selvamanickam, V. [SuperPower, 450 Duane Ave, Schenectady, NY 12304 (United States)

    2007-10-01

    Reduction of ac losses in applied ac fields can be accomplished through either the creation of filaments and bridging in YBCO coated conductors or by an assembly of narrow width YBCO tapes. The ac losses for each of these geometries were measured at 77 K in perpendicular ac fields up to 100 mT. Despite physical isolation of the filaments, coupling losses were still present in the samples when compared to the expected hysteretic loss. In addition to filamentary conductors the assembly of stacked YBCO conductor provides an alternative method of ac loss reduction. When compared to a 4-mm wide YBCO coated conductor with a critical current of 60 A, the ac loss in a stack of 2-mm wide YBCO coated conductors with a similar total critical current was reduced. While the reduction in ac loss in a 2-mm wide stack coincided with the reduction in the engineering current density of the conductor, further reduction of ac loss was obtained through the splicing of the 2-mm wide tapes with low resistance solders.

  17. Thin film conductors for self-equalizing cables

    Science.gov (United States)

    Owen, G.; Trutna, W. R.; Orsley, T. J.; Lucia, F.; Daly, C. B.

    2017-10-01

    Self-equalizing cables using hollow conductors with wall thickness less than the skin depth were proposed in 1929. However, they do not appear ever to have been widely used, although the idea has resurfaced and been refined from time to time. In the early 2000's, self-equalizing conductors consisting of solid magnetic steel cores coated with silver were developed by W.L. Gore, and used in their 2.5 Gb/s "Eye-Opener" cables, although higher speed versions never appeared. We have revived the original 1929 idea, proposing to use glass as a solid insulating core. This technology can potentially work at frequencies of many 10's of GHz. Possible uses include short range GHz links such as USB and Thunderbolt, and intra-rack interconnections in data centers. Our feasibility experiments have validated the principle. Copper coated glass fibers can, in principle, be manufactured, but in these tests, the conductors were capillaries internally coated with silver as these are easily obtainable, relatively inexpensive and serve to test the concept. The performance of these experimental twin lead cables corresponds to calculations, confirming the general principle. By calculation, we have compared the performance of cables made from copper-on-insulator conductors to that of similar cables made with solid copper conductors, and verified that copper-on-insulator cables have significantly less frequency dependent loss. We have also made and tested cables with copper on PEEK conductors as surrogates for copper on glass fiber.

  18. Design of force-cooled conductors for large fusion magnets

    International Nuclear Information System (INIS)

    Dresner, L.; Lue, J.W.

    1977-01-01

    One type of conductor under consideration for tokamak toroidal field (TF) magnets is a cable-in-conduit cooled by supercritical helium in forced convection. The main problem is designing such force-cooled conductors (fcc) is to maintain adequate stability while keeping the pumping power tolerably low. The transit time of the helium through a coil is many minutes. Since recovery of the conductor from a thermomechanical perturbation takes on the order of tens of milliseconds, for purposes of calculation, the inventory of helium available to promote recovery is finite. This means that a large enough perturbation will quench the conductor. We can then judge the stability of a fcc by the maximum perturbation of some specified type against which the conductor is stable, i.e., can still return to the superconducting state. The simplest type of perturbation is a sudden, uniform heat input over the entire length of the conductor. The maximum, sudden, uniform heat input per unit volume of metal ΔH is called the ''stability margin.''

  19. Electrical properties of molecular crystals

    International Nuclear Information System (INIS)

    Barraud, A.

    1968-01-01

    This literature survey summarizes the electrical properties of molecular crystals: molecular crystal structure, transport and excitation mechanisms of charge-carriers, and differences compared to inorganic semi-conductors. The main results concerning the electrical conductivity of the most-studied molecular crystals are presented, together with the optical and photo-electrical properties of these crystals. Finally the different types of electrical measurements used are reviewed, as well as the limits of each method. (author) [fr

  20. Origin of activation energy in a superionic conductor

    International Nuclear Information System (INIS)

    Kamishima, O; Kawamura, K; Hattori, T; Kawamura, J

    2011-01-01

    The characteristics of cation diffusion with many-body effects are discussed using Ag β-alumina as an example of a superionic conductor. Polarized Raman spectra of Ag β-alumina have been measured at room temperature. The interatomic potentials were determined by a non-linear least square fitting between the phonon eigenvalues from the Raman observations and a dynamical matrix calculation based on a rigid-ion model. The obtained potential parameters for the model crystal of Ag β-alumina successfully reproduce the macroscopic properties with respect to the heat capacity, isothermal compressibility and self-diffusion constant. A molecular dynamics (MD) calculation has been carried out using the model crystal of Ag β-alumina to understand the many-body effects for the fast ionic diffusion. It was found that the Ag-Ag repulsion by excess Ag defects significantly reduced the cost of the energy difference of the occupancy between the stable and metastable sites. It is possible for the system to take various configurations of the mobile ions through defects easily, and then the fast ionic diffusion will appear. On the other hand, the Ag-Ag repulsion changes the dynamics of the Ag ions from a random hopping to a cooperative motion. In the cooperative motion, the ionic transport becomes difficult due to the additional energy required for the structural relaxation of the surrounding Ag ions. We propose a new insight into the superionic conduction, that is, the activation energy for the ionic transport is composed of two kinds of elements: a 'static' activation energy and a 'dynamic' one. The static activation energy is the cost of the averaged energy difference in the various structural configurations in the equilibrium state. The dynamic activation energy is the additional energy required for the structural relaxation induced by the jump process.

  1. Texture development of HTS powder-in-tube conductors

    Energy Technology Data Exchange (ETDEWEB)

    Glowacki, B A [IRC in Superconductivity, University of Cambridge, Cambridge (United Kingdom); Department of Materials Science and Metallurgy, University of Cambridge, Cambridge (United Kingdom)

    1998-10-01

    An overview of the fabrication and electromagnetic properties of high-temperature conductors processed by the powder-in-tube (PIT) technique with reference to texture development and critical anisotropy data is presented. Special emphasis is given to the optimization of the physicochemical and electromagnetic parameters of the multifilamentary and single-filament conductors with superconducting cores of Bi-2223, Tl-1223 and Y-123 superconducting phases. The influence of the multifilamentary and single-filament structures on texture development is discussed. Also, the importance of the local disturbances of the grain alignment and microdefects for the current distribution across and in the plane of the whole conductor is analysed. A comparative study of the critical current anisotropy with field direction in low magnetic fields of Tl-1223 and Bi-2223 conductors manufactured by the PIT technique is presented. For Tl-1223 PIT conductors the anisotropy coefficient shows a very pronounced minimum, followed by a monotonic reduction of anisotropy with the increase of the magnetic field. This is explained in terms of poor grain alignment with weak intergranular superconducting coupling which cause 3D current percolation and also by the demagnetizing effect of the grains and the ceramic core in the PIT Tl-1223 tapes. (author)

  2. Fabrication and tests of EF conductors for JT-60SA

    Energy Technology Data Exchange (ETDEWEB)

    Kizu, Kaname, E-mail: kizu.kaname@jaea.go.jp [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan); Kashiwa, Yoshitoshi; Murakami, Haruyuki [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan); Obana, Tetsuhiro; Takahata, Kazuya [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Tsuchiya, Katsuhiko; Yoshida, Kiyoshi [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan); Hamaguchi, Shinji [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Matsui, Kunihiro [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan); Nakamura, Kazuya; Takao, Tomoaki [Sophia University, Tokyo 102-8554 (Japan); Yanagi, Nagato; Imagawa, Shinsaku; Mito, Toshiyuki [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan)

    2011-10-15

    The conductors for plasma equilibrium field (EF) coils of JT-60SA are NbTi cable-in-conduit (CIC) conductor with stainless steel 316L jacket. The production of superconductors for actual EF coils started from February 2010. Nine superconductors with 444 m in length were produced up to July 2010. More than 300 welding of jackets were performed. Six nonconformities were found by inspections as go gauge, visual inspection and X-ray test. In order to shorten the manufacturing time schedule, helium leak test was conducted at once after connecting the long length jacket not just after the welding. The maximum force to pull the cable into jacket was about 7.6 kN on average. The mass flow rates of 9 conductors showed almost same values indicating that there are no blockages in the conductors. The measured current sharing temperature agreed with the expectation values from strand performance indicating that no degradation was caused by production process. The coupling time constants of conductors ranged from 80 to 90 ms which are much smaller than the design value of 200 ms.

  3. Use of ion conductors in the pyrochemical reduction of oxides

    International Nuclear Information System (INIS)

    Miller, W.E.; Tomczuk, Z.

    1994-01-01

    An electrochemical process and electrochemical cell for reducing a metal oxide are provided. First the oxide is separated as oxygen gas using, for example, a ZrO 2 oxygen ion conductor anode and the metal ions from the reduction salt are reduced and deposited on an ion conductor cathode, for example, sodium ion reduced on a β-alumina sodium ion conductor cathode. The generation of and separation of oxygen gas avoids the problem with chemical back reaction of oxygen with active metals in the cell. The method also is characterized by a sequence of two steps where an inert cathode electrode is inserted into the electrochemical cell in the second step and the metallic component in the ion conductor is then used as the anode to cause electrochemical reduction of the metal ions formed in the first step from the metal oxide where oxygen gas formed at the anode. The use of ion conductors serves to isolate the active components from chemically reacting with certain chemicals in the cell. While applicable to a variety of metal oxides, the invention has special importance for reducing CaO to Ca o used for reducing UO 2 and PuO 2 to U and Pu. 2 figures

  4. Hearing status among Norwegian train drivers and train conductors.

    Science.gov (United States)

    Lie, A; Skogstad, M; Johnsen, T S; Engdahl, B; Tambs, K

    2013-12-01

    There is a general perception that train drivers and conductors may be at increased risk of developing noise-induced hearing loss. To study job-related hearing loss among train drivers and train conductors. Audiograms from train drivers and train conductors were obtained from the medical records of the occupational health service of the major Norwegian railway company. The results were compared with audiograms from an internal control group of railway workers and an external reference group of people not occupationally exposed to noise. The monaural hearing threshold level at 4kHz, the mean binaural value at 3, 4 and 6kHz and the prevalence of audiometric notches (≥25 dB at 4kHz) were used for comparison. Audiograms were available for 1567 drivers, 1565 conductors, 4029 railway worker controls and 15 012 people not occupationally exposed to noise. No difference in hearing level or prevalence of audiometric notches was found between study groups after adjusting for age and gender. Norwegian train drivers and conductors have normal hearing threshold levels comparable with those in non-exposed groups.

  5. Design of force-cooled conductors for large fusion magnets

    Energy Technology Data Exchange (ETDEWEB)

    Dresner, L.; Lue, J.W.

    1977-01-01

    Conductors cooled by supercritical helium in forced convection are under active consideration for large toroidal fusion magnets. One of the central problems in designing such force cooled conductors is to maintain an adequate stability margin while keeping the pumping power tolerably low. A method has been developed for minimizing the pumping power for fixed stability by optimally choosing the matrix-to-superconductor and the metal-to-helium ratios. Such optimized conductors reduce pumping power requirements for fusion size magnets to acceptable limits. Furthermore, the mass flow and hence pumping losses can be varied through a magnet according to the local magnetic field and magnitude of desired stability margin. Force cooled conductors give flexibility in operation, permitting, for example, higher fields to be obtained than originally intended by lowering the bath temperature or increasing the pumping power or both. This flexibility is only available if the pumping power is low to begin with. Scaling laws for the pumping requirement and stability margin as functions of operating current density, number of strands and such physical parameters as stabilizer resistivity and critical current density, have been proved. Numerical examples will be given for design of conductors intended for use in large toroidal fusion magnet systems.

  6. Qualification tests for ITER TF conductors in SULTAN

    International Nuclear Information System (INIS)

    Bruzzone, P.; Stepanov, B.; Wesche, R.

    2009-01-01

    From February 2007 to May 2008, 18 short length conductor sections have been tested in SULTAN for design verification and manufacturer qualification of the ITER Toroidal Field (TF) conductor. The test program is focussed on the current sharing temperature, T cs , at the nominal operating conditions, 68 kA current and 11.15 T effective field, which can be fully reproduced in the SULTAN test facility. A broad range of results was observed, with over 2 K difference among the T cs of the conductors. In average, the results are poorer compared to the potential performance estimated from the strand scaling law. The key parameters to mitigate the degradation are not yet clearly identified. The experimental challenges to test conductors with performance degradation are highlighted, including enhanced instrumentation sets, the application of gas flow calorimetry to sense the current sharing power and the post-processing of voltage data to cancel the transverse potential across the cable. The updated schedule of the tests in SULTAN is presented with the short-term action plan for conductor test.

  7. Design of force-cooled conductors for large fusion magnets

    International Nuclear Information System (INIS)

    Dresner, L.; Lue, J.W.

    1977-01-01

    Conductors cooled by supercritical helium in forced convection are under active consideration for large toroidal fusion magnets. One of the central problems in designing such force cooled conductors is to maintain an adequate stability margin while keeping the pumping power tolerably low. A method has been developed for minimizing the pumping power for fixed stability by optimally choosing the matrix-to-superconductor and the metal-to-helium ratios. Such optimized conductors reduce pumping power requirements for fusion size magnets to acceptable limits. Furthermore, the mass flow and hence pumping losses can be varied through a magnet according to the local magnetic field and magnitude of desired stability margin. Force cooled conductors give flexibility in operation, permitting, for example, higher fields to be obtained than originally intended by lowering the bath temperature or increasing the pumping power or both. This flexibility is only available if the pumping power is low to begin with. Scaling laws for the pumping requirement and stability margin as functions of operating current density, number of strands and such physical parameters as stabilizer resistivity and critical current density, have been proved. Numerical examples will be given for design of conductors intended for use in large toroidal fusion magnet systems

  8. Molecular dynamics simulations of quasi-brittle crack development in iron

    Energy Technology Data Exchange (ETDEWEB)

    Borodin, V.A., E-mail: borodin@dni.polin.kiae.su [Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe (Germany); NRC Kurchatov Institute, Kurchatov Sq. 1, 123182 Moscow (Russian Federation); Vladimirov, P.V., E-mail: Pavel.Vladimirov@kit.edu [Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe (Germany)

    2011-08-31

    The paper presents the results of molecular dynamics (MD) simulations of three-dimensional kinetics of micro-crack propagation in alpha-iron and the accompanying lattice transformations at the crack tips. We show that crack initiation on {l_brace}0 0 1{r_brace} planes in iron is preceded with the emission of compact slip bands from the pre-crack tips, in agreement with the predictions of the earlier quasi-two-dimensional simulations. The application of Voronoi decomposition technique for atomic short-range order processing has allowed us to clarify the kinetics of structural transformations at the tips of nucleating and propagating cracks for three most common systems of crack propagation in iron. It is demonstrated that the compact slip bands emanating from the crack tips not only accompany crack nucleation, but remain an essential feature of the crack propagation on {l_brace}0 0 1{r_brace} planes. Due to the strong coupling between the crack tip and slip band propagation, the crack propagation can be limited by slip band interaction with microstructural obstacles, abundantly created in ferritic-martensitic steels in radiation environment of nuclear facilities.

  9. Wiring assembly and method of forming a channel in a wiring assembly for receiving conductor and providing separate regions of conductor contact with the channel

    Energy Technology Data Exchange (ETDEWEB)

    Stelzer, Gerald; Meinke, Rainer; Senti, Mark

    2018-03-06

    A conductor assembly and method for constructing an assembly of the type which, when conducting current, generates a magnetic field or which, in the presence of a changing magnetic field, induces a voltage. In one embodiment the method provides a first insulative layer tubular in shape and including a surface along which a conductor segment may be positioned. A channel formed in the surface of the insulative layer defines a first conductor path and includes a surface of first contour in cross section along a first plane transverse to the conductor path. A segment of conductor having a surface of second contour in cross section is positioned at least partly in the channel and extends along the conductor path. Along the first plane, contact between the conductor surface of second contour and the channel surface of first contour includes at least two separate regions of contact.

  10. Thermodynamic behaviour of a coated conductor for currents above Ic

    International Nuclear Information System (INIS)

    Schwarz, M; Schacherer, Chr; Weiss, K-P; Jung, A

    2008-01-01

    Coated conductors are becoming more and more applicable. The temperature range below the critical value (T c ) or below the critical current (I c ) is well characterized. But for applications such as fault current limiters, which take advantage of the superconducting-to-normal transition, characterization beyond the superconducting regime is mandatory. Therefore, this work studies the thermodynamic behaviour of a coated conductor immersed in boiling liquid nitrogen which is driven by a sinusoidal over-current of up to more than five times I c . The temperature of the coated conductor exceeds 720 K without any significant degradation. To validate this current-induced high-temperature region, the resistance of the composite tape is measured from T c to 600 K. A thermodynamic and electrical model is conceptualized for calculating the temperature, developing as a function of time during over-currents. The calculated temperature fits well with the measured temperature

  11. Benefits of current percolation in superconducting coated conductors

    International Nuclear Information System (INIS)

    Rutter, N.A.; Durrell, J.H.; Blamire, M.G.; MacManus-Driscoll, J.L.; Wang, H.; Foltyn, S.R.

    2005-01-01

    The critical currents of coated conductors fabricated by metal-organic deposition (MOD) on rolling-assisted biaxially textured substrates (RABiTS) and by pulsed laser deposition (PLD) on ion-beam assisted deposition (IBAD) templates have been measured as a function of magnetic field orientation and compared to films grown on single crystal substrates. By varying the orientation of magnetic field applied in the plane of the film, we are able to determine the extent to which current flow in each type of conductor is percolative. Standard MOD/RABiTS conductors have also been compared to samples whose grain boundaries have been doped by diffusing Ca from an overlayer. We find that undoped MOD/RABiTS tapes have a less anisotropic in-plane field dependence than PLD/IBAD tapes and that the uniformity of critical current as a function of in-plane field angle is greater for MOD/RABiTS samples doped with Ca

  12. Characterization of textile electrodes and conductors using standardized measurement setups

    International Nuclear Information System (INIS)

    Beckmann, L; Neuhaus, C; Medrano, G; Walter, M; Leonhardt, S; Jungbecker, N; Gries, T

    2010-01-01

    Textile electrodes and conductors are being developed and used in different monitoring scenarios, such as ECG or bioimpedance spectroscopy measurements. Compared to standard materials, conductive textile materials offer improved wearing comfort and enable long-term measurements. Unfortunately, the development and investigation of such materials often suffers from the non-reproducibility of the test scenarios. For example, the materials are generally tested on human skin which is difficult since the properties of human skin differ for each person and can change within hours. This study presents two test setups which offer reproducible measurement procedures for the systematic analysis of textile electrodes and conductors. The electrode test setup was designed with a special skin dummy which allows investigation of not only the electrical properties of textile electrodes but also the contact behavior between electrode and skin. Using both test setups, eight textile electrodes and five textile conductors were analyzed and compared

  13. Nb3Sn conductor development for the ITER magnets

    International Nuclear Information System (INIS)

    Mitchell, N.

    1997-01-01

    The ITER magnet system consists of Toroidal Field (TF) coils, Poloidal Field (PF) coils, the Central Solenoid (CS) and error field correction coils (CC). The conductors for the coils are Nb 3 Sn or NbTi cable in conduit type, forced flow cooled with supercritical helium having a maximum operating current in the range 40-60 kA. To qualify the Nb 3 Sn conductor, two large model coils (energy up to 640 MJ) are being wound by the Home Teams of the Parties to the ITER EDA Agreement. A total of 24 t of strand has been completed for the CS model coil and 4 t for the TF model coil, and fabricated into 7 km of conductor in unit lengths up to 210 m, by an international collaboration involving 12 companies in Europe, Japan, Russia and the USA

  14. Tension layer winding of cable-in-conduit conductor

    International Nuclear Information System (INIS)

    Devernoe, A.; Ciancetta, G.; King, M.; Parizh, M.; Painter, T.; Miller, J.

    1996-01-01

    A 710 mm i.d. by 440 mm long, 6 layer Cable-in-Conduit (CIC) coil was precision tension layer wound with Incoloy 908 jacketed conductor to model winding technology that will be used for the Nb 3 Sn outsert coils of the 45 Tesla Hybrid Magnet Project at the US National High Magnetic Field Laboratory. This paper reports on the set up of a new winding facility with unique capabilities for insulating and winding long length CIC conductor and on special procedures which were developed to wind and support layer to layer transitions and to safely form conductor into and out of the winding. Analytical methods used to predict conduit keystoning, springback and back tensioning requirements before winding are reported in comparison to results obtained during winding and actual winding build-up dimensions on a layer by layer basis in comparison to design requirements

  15. Thin film conductors for self-equalizing cables

    Directory of Open Access Journals (Sweden)

    G. Owen

    2017-10-01

    Full Text Available Self-equalizing cables using hollow conductors with wall thickness less than the skin depth were proposed in 1929. However, they do not appear ever to have been widely used, although the idea has resurfaced and been refined from time to time. In the early 2000’s, self-equalizing conductors consisting of solid magnetic steel cores coated with silver were developed by W.L. Gore, and used in their 2.5 Gb/s “Eye-Opener” cables, although higher speed versions never appeared. We have revived the original 1929 idea, proposing to use glass as a solid insulating core. This technology can potentially work at frequencies of many 10’s of GHz. Possible uses include short range GHz links such as USB and Thunderbolt, and intra-rack interconnections in data centers. Our feasibility experiments have validated the principle. Copper coated glass fibers can, in principle, be manufactured, but in these tests, the conductors were capillaries internally coated with silver as these are easily obtainable, relatively inexpensive and serve to test the concept. The performance of these experimental twin lead cables corresponds to calculations, confirming the general principle. By calculation, we have compared the performance of cables made from copper-on-insulator conductors to that of similar cables made with solid copper conductors, and verified that copper-on-insulator cables have significantly less frequency dependent loss. We have also made and tested cables with copper on PEEK conductors as surrogates for copper on glass fiber.

  16. Improvement of SOFC electrodes using mixed ionic-electronic conductors

    Energy Technology Data Exchange (ETDEWEB)

    Matsuzaki, Y.; Hishinuma, M. [Tokyo Gas Co., Ltd. (Japan)

    1996-12-31

    Since the electrode reaction of SOFC is limited to the proximity of a triple phase boundary (TPB), the local current density at the electrode and electrolyte interface is larger than mean current density, which causes large ohmic and electrode polarization. This paper describes an application of mixed ionic-electronic conductors to reduce such polarization by means of (1) enhancing ionic conductivity of the electrolyte surface layer by coating a high ionic conductors, and (2) reducing the local current density by increasing the electrochemically active sites.

  17. Thin film conductors for self-equalizing cables

    OpenAIRE

    G. Owen; W. R. Trutna; T. J. Orsley; F. Lucia; C. B. Daly

    2017-01-01

    Self-equalizing cables using hollow conductors with wall thickness less than the skin depth were proposed in 1929. However, they do not appear ever to have been widely used, although the idea has resurfaced and been refined from time to time. In the early 2000’s, self-equalizing conductors consisting of solid magnetic steel cores coated with silver were developed by W.L. Gore, and used in their 2.5 Gb/s “Eye-Opener” cables, although higher speed versions never appeared. We have revived the or...

  18. 33 CFR 183.435 - Conductors in circuits of 50 volts or more.

    Science.gov (United States)

    2010-07-01

    ... HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Electrical Systems Manufacturer... more. (c) This section does not apply to communication systems; electronic navigation equipment; resistance conductors that control circuit amperage; conductors in secondary circuits of ignition systems...

  19. Cognitive and collaborative demands of freight conductor activities: results and implications of a cognitive task analysis

    Science.gov (United States)

    2012-07-31

    This report presents the results of a cognitive task analysis (CTA) that examined the cognitive and collaborative demands placed on conductors, as well as the knowledge and skills that experienced conductors have developed that enable them to operate...

  20. Design of a Wireless Sensor Module for Monitoring Conductor Galloping of Transmission Lines.

    Science.gov (United States)

    Huang, Xinbo; Zhao, Long; Chen, Guimin

    2016-10-09

    Conductor galloping may cause flashovers and even tower collapses. The available conductor galloping monitoring methods often employ acceleration sensors to measure the conductor translations without considering the conductor twist. In this paper, a new sensor for monitoring conductor galloping of transmission lines based on an inertial measurement unit and wireless communication is proposed. An inertial measurement unit is used for collecting the accelerations and angular rates of a conductor, which are further transformed into the corresponding geographic coordinate frame using a quaternion transformation to reconstruct the galloping of the conductor. Both the hardware design and the software design are described in details. The corresponding test platforms are established, and the experiments show the feasibility and accuracy of the proposed monitoring sensor. The field operation of the proposed sensor in a conductor spanning 734 m also shows its effectiveness.

  1. Conductor Temperature Estimation and Prediction at Thermal Transient State in Dynamic Line Rating Application

    DEFF Research Database (Denmark)

    Alvarez, David L.; Silva, Filipe Miguel Faria da; Mombello, Enrique Esteban

    2018-01-01

    . This paper presents an algorithm to estimate and predict the temperature in overhead line conductors using an Extended Kalman Filter. The proposed algorithm assumes both actual weather and current intensity flowing along the conductor as control variables. The temperature of the conductor, mechanical tension...

  2. Violence Against Drivers and Conductors in the Road Passenger ...

    African Journals Online (AJOL)

    This cross-sectional study examined the extent, nature and risk factors of workplace violence in the road passenger transport sector in Maputo, the capital city of Mozambique. A random sample of 504 participants was selected from a population of 2 618 registered bus, minibus, and taxi drivers/conductors. The results ...

  3. Intermediate Temperature Proton Conductors – Why and How

    DEFF Research Database (Denmark)

    Li, Qingfeng; Aili, David; Jensen, Jens Oluf

    represented by early fundamental material research for ionic electrolytes. Such materials, most likely based on proton conductors, are expected to bring a new generation of the technologies: fuel cells by direct oxidation or internal splitting of biofuels such as methanol and ethanol, as well as efficient...

  4. Comparative characterization of Cu–Ni substrates for coated conductors

    DEFF Research Database (Denmark)

    Tian, H.; Suo, H.L.; Wulff, Anders Christian

    2014-01-01

    Three Cu100xNix alloys, with x = 23, 33 and 45 at.%Ni, have been evaluated for use as substrates for coated conductors on the basis of measurements of their microstructure, crystallographic texture and hardness. It is found that high-temperature annealing after heavy rolling generates strong cube...

  5. Temporal interaction between an artificial orchestra conductor and human musicians

    NARCIS (Netherlands)

    Reidsma, Dennis; Nijholt, Antinus; Bos, Pieter

    2008-01-01

    The Virtual Conductor project concerns the development of the first properly interactive virtual orchestra conductor—a Virtual Human that can conduct a piece of music through interaction with musicians, leading and following them while they are playing. This article describes our motivation for

  6. Conductor and Ensemble Performance Expressivity and State Festival Ratings

    Science.gov (United States)

    Price, Harry E.; Chang, E. Christina

    2005-01-01

    This study is the second in a series examining the relationship between conducting and ensemble performance. The purpose was to further examine the associations among conductor, ensemble performance expressivity, and festival ratings. Participants were asked to rate the expressivity of video-only conducting and parallel audio-only excerpts from a…

  7. An Organic Mixed Ion-Electron Conductor for Power Electronics

    DEFF Research Database (Denmark)

    Malti, Abdellah; Edberg, Jesper; Granberg, Hjalmar

    2016-01-01

    A mixed ionic–electronic conductor based on nanofibrillated cellulose composited with poly(3,4-ethylene-dioxythio­phene):­poly(styrene-sulfonate) along with high boiling point solvents is demonstrated in bulky electrochemical devices. The high electronic and ionic conductivities of the resulting...

  8. An Organic Mixed Ion–Electron Conductor for Power Electronics

    DEFF Research Database (Denmark)

    Malti, Abdellah; Edberg, Jesper; Granberg, Hjalmar

    2016-01-01

    A mixed ionic–electronic conductor based on nanofibrillated cellulose composited with poly(3,4-ethylene-dioxythio­phene):­poly(styrene-sulfonate) along with high boiling point solvents is demonstrated in bulky electrochemical devices. The high electronic and ionic conductivities of the resulting...

  9. Structural analysis of the NET toroidal field coils and conductor

    International Nuclear Information System (INIS)

    Mitchell, N.; Collier, D.; Gori, R.

    1989-01-01

    The NET toroidal field coils will utilise A15-type superconductor at 4.2 K to generate fields up to 11.5 T. The superconductor strands themselves are sensitive to strain, which causes degradation of their current carrying capacity, and thus the detailed behaviour of the coil conductor must be analysied so that the strian can be minimised. This analysis must include the manufacturing processes of the conductor as well as the normal and abnormal loperational loads. The conductor will be insulated and bonded by glass fibre reinforced epoxy resin, with limited bonding shear strength, and the overall support of the complete coil system must be designed to reduce these shear stresses. The coils will be subjected to pulse loads form the poloidal field coils, and analysis of the slip between the various coil components, such as conductors and the coil case, giving rise to frictional heating and possible loss of superconducting properties is another important factor, which has been investigated by a number of stress analyses. The manufacturing, thermal and normal magnetic loads on the coils and the analysis leading to the proposed structural design are described. In addition to the normal operating conditions, there is a range of abnormal load conditions which could result from electrical or mechanical faults on the coils. The effect of these potential faults has been analysed and the coil design modified to prevent catastrophic structural failure. (author). 13 refs.; 8 figs.; 1 tab

  10. H/D isotope effects in high temperature proton conductors

    DEFF Research Database (Denmark)

    Bonanos, Nikolaos; Huijser, A.; Poulsen, Finn Willy

    2015-01-01

    The atomic mass ratio of ca. 2 between deuterium and hydrogen is the highest for any pair of stable isotopes and results in significant and measurable H/D isotope effects in high temperature proton conductors containing these species. This paper discusses H/D isotope effects manifested in O-H/O-D...

  11. Non-equilibrium and band tailing in organic conductors

    Indian Academy of Sciences (India)

    . Non-equilibrium ... Introduction. Study of organic conductors and semiconductors continues to generate interest with the ... Band tailing reduces band gap or the acti- ..... (9), we can identify Eg(0) with the focal point and is proportional to P2. 1 .

  12. The electric field of a current-carrying conductor

    International Nuclear Information System (INIS)

    Strel'tsov, V.N.

    1991-01-01

    A subject concerning the relativistic invariance of the Gauss theorem has been discussed. The appearance of the electric field around the neutral conductor after excitation of current in it doesn't signify the change of its charge. 8 refs.; 1 fig

  13. Attentional flexibility and memory capacity in conductors and pianists.

    Science.gov (United States)

    Wöllner, Clemens; Halpern, Andrea R

    2016-01-01

    Individuals with high working memory (WM) capacity also tend to have better selective and divided attention. Although both capacities are essential for skilled performance in many areas, evidence for potential training and expertise effects is scarce. We investigated the attentional flexibility of musical conductors by comparing them to equivalently trained pianists. Conductors must focus their attention both on individual instruments and on larger sections of different instruments. We studied students and professionals in both domains to assess the contributions of age and training to these skills. Participants completed WM span tests for auditory and visual (notated) pitches and timing durations, as well as long-term memory tests. In three dichotic attention tasks, they were asked to detect small pitch and timing deviations from two melodic streams presented in baseline (separate streams), selective-attention (concentrating on only one stream), and divided-attention (concentrating on targets in both streams simultaneously) conditions. Conductors were better than pianists in detecting timing deviations in divided attention, and experts detected more targets than students. We found no group differences for WM capacity or for pitch deviations in the attention tasks, even after controlling for the older age of the experts. Musicians' WM spans across multimodal conditions were positively related to selective and divided attention. High-WM participants also had shorter reaction times in selective attention. Taken together, conductors showed higher attentional flexibility in successfully switching between different foci of attention.

  14. Effect of annular secondary conductor in a linear electromagnetic ...

    Indian Academy of Sciences (India)

    This paper presents the variation of average axial force density in the annular secondary conductor of a linear electromagnetic stirrer. Different geometries of secondaries are considered for numerical and experimental validation namely, 1. hollow annular ring, 2. annular ring with a solid cylinder and 3. solid cylinder.

  15. 30 CFR 57.12080 - Bare conductor guards.

    Science.gov (United States)

    2010-07-01

    ....12080 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Electricity... conductors are less than 7 feet above the rail, they shall be guarded at all points where persons work or...

  16. Exploring a Metamorphosis: Identity Formation for an Emerging Conductor

    Science.gov (United States)

    Ponchione, Cayenna

    2013-01-01

    Exploring the manner in which professional identity formation in emerging conductors is entangled with the cultural context of orchestras, I focus on the amorphous evolution from a student identity to that of a professional, illuminating some underlying social conditions of the ever-elusive profession of conducting. Prevailing assumptions about…

  17. Charge densities and charge noise in mesoscopic conductors

    Indian Academy of Sciences (India)

    This generalization leads to a local Wigner–Smith life-time matrix. Keywords. Density ... Of interest is the charge distribution in such a conductor and ..... is the transmission probability of the scattering problem without absorption if .... as a voltage probe which has its potential adjusted in such a way that there is no net current.

  18. Influence of the magnetic field profile on ITER conductor testing

    International Nuclear Information System (INIS)

    Nijhuis, A; Ilyin, Y; Kate, H H J ten

    2006-01-01

    We performed simulations with the numerical CUDI-CICC code on a typical short ITER (International Thermonuclear Experimental Reactor) conductor test sample of dual leg configuration, as usually tested in the SULTAN test facility, and made a comparison with the new EFDA-Dipole test facility offering a larger applied DC field region. The new EFDA-Dipole test facility, designed for short sample testing of conductors for ITER, has a homogeneous high field region of 1.2 m, while in the SULTAN facility this region is three times shorter. The inevitable non-uniformity of the current distribution in the cable, introduced by the joints at both ends, has a degrading effect on voltage-current (VI) and voltage-temperature (VT) characteristics, particularly for these short samples. This can easily result in an underestimation or overestimation of the actual conductor performance. A longer applied DC high field region along a conductor suppresses the current non-uniformity by increasing the overall longitudinal cable electric field when reaching the current sharing mode. The numerical interpretation study presented here gives a quantitative analysis for a relevant practical case of a test of a short sample poloidal field coil insert (PFCI) conductor in SULTAN. The simulation includes the results of current distribution analysis from self-field measurements with Hall sensor arrays, current sharing measurements and inter-petal resistance measurements. The outcome of the simulations confirms that the current uniformity improves with a longer high field region but the 'measured' VI transition is barely affected, though the local peak voltages become somewhat suppressed. It appears that the location of the high field region and voltage taps has practically no influence on the VI curve as long as the transverse voltage components are adequately cancelled. In particular, for a thin conduit wall, the voltage taps should be connected to the conduit in the form of an (open) azimuthally

  19. Verification of a Novel Method of Detecting Faults in Medium-Voltage Systems with Covered Conductors

    Directory of Open Access Journals (Sweden)

    Mišák Stanislav

    2017-06-01

    Full Text Available This paper describes the use of new methods of detecting faults in medium-voltage overhead lines built of covered conductors. The methods mainly address such faults as falling of a conductor, contacting a conductor with a tree branch, or falling a tree branch across three phases of a medium-voltage conductor. These faults cannot be detected by current digital relay protection systems. Therefore, a new system that can detect the above mentioned faults was developed. After having tested its operation, the system has already been implemented to protect mediumvoltage overhead lines built of covered conductors.

  20. New tests on the 40 kA Nb3Sn CEA conductor for ITER applications

    International Nuclear Information System (INIS)

    Duchateau, J.L.; Bessette, D.; Katheder, H.

    1994-01-01

    New tests have been performed on the 40 kA CEA Nb 3 Sn conductor in the Sultan III facility. The aim of these tests is to obtain key experimental data on the behaviour of Nb 3 Sn conductors for fusion applications under high field and large transport current. The 40 kA Nb 3 Sn CEA conductor has a shape and an internal arrangement of the superconducting wires which is very similar to the ITER conductors. The level of the ac losses experienced by these conductors under varying fields influences deeply their design. The basic experiment consists of producing field pulses on the conductor by means of a coil installed in the bore of the Sultan magnet and recording the integrated voltage obtained on pick-up coils placed on the conductor as a function of time. (author) 4 refs.; 5 figs.; 2 tabs

  1. Electrostatic separation for recycling conductors, semiconductors, and nonconductors from electronic waste.

    Science.gov (United States)

    Xue, Mianqiang; Yan, Guoqing; Li, Jia; Xu, Zhenming

    2012-10-02

    Electrostatic separation has been widely used to separate conductors and nonconductors for recycling e-waste. However, the components of e-waste are complex, which can be classified as conductors, semiconductors, and nonconductors according to their conducting properties. In this work, we made a novel attempt to recover the mixtures containing conductors (copper), semiconductors (extrinsic silicon), and nonconductors (woven glass reinforced resin) by electrostatic separation. The results of binary mixtures separation show that the separation of conductor and nonconductor, semiconductor and nonconductor need a higher voltage level while the separation of conductor and semiconductor needs a higher roll speed. Furthermore, the semiconductor separation efficiency is more sensitive to the high voltage level and the roll speed than the conductor separation efficiency. An integrated process was proposed for the multiple mixtures separation. The separation efficiency of conductors and semiconductors can reach 82.5% and 88%, respectively. This study contributes to the efficient recycling of valuable resources from e-waste.

  2. Ionic diffusion in superionic-conductor melts

    International Nuclear Information System (INIS)

    Tankeshwar, K.; Tosi, M.P.

    1991-03-01

    The self-diffusion coefficients D + and D - of the two ionic species in molten AgI, CuCl, CuBr and CuI are evaluated and contrasted with those calculated for molten NaCl. The evaluation adopts a simple model for liquid state dynamics, earlier proposed by Zwanzig to justify the Stokes-Einstein formula for monatomic fluids, and by suitable approximations relates the self-diffusion coefficients to pair potentials and to the pair structure of the melt. The results offer an interpretation for molecular dynamics data showing that, whereas for a ''normal'' system such as NaCl the ratio D + /D - in the melt is of the order unity, a sizable difference between D + and D - persists in salts melting from a fast-cation conducting solid. This difference is explicitly related to liquid structure through differences in the structural backscattering of cations by cations and of halogens by halogens. The calculated magnitudes of D + /D - are quite satisfactory, while the absolute magnitudes of D + and D - are in good agreement with the data only for those salts (AgI, CuBr and NaCl) in which the masses of the two ionic species are not greatly different. (author). 21 refs, 2 tabs

  3. Bending Test of Conductor for ALICE and LHCb Dipole Magnets

    CERN Document Server

    Giudici, P A; CERN. Geneva; Flegel, W

    2000-01-01

    Abstract It is foreseen that the coils for the two magnets will be manufactured by winding flat pancakes, which are subsequently shaped to a semi-cylindrical form (ALICE) or bent by 45 degrees (LHCb). We propose here several methods and describe tests that were performed to estimate tolerances and forces which will have to be expected during the manufacturing process. To this end, short Aluminium conductor lengths of adequate cross-section were bent around a shaper piece to an angle of 90 degrees. The tests were repeated for conductors both wrapped with prepreg insulation tape and without this tape. The different test set-ups and the obtained results are described in this note.

  4. The electrostatics of charged insulating sheets peeled from grounded conductors

    International Nuclear Information System (INIS)

    Datta, M J; Horenstein, M N

    2008-01-01

    The physics of a charged, insulating sheet peeled from a ground-plane conductor is examined. Contact charging is ensured by charging a sheet to 10-12 kV with corona to establish intimate electrostatic contact with the underlying conductor. The surface potential is next forced to zero by sweeping the sheet with a stainless-steel brush, and the surface recharged to a new potential between 0 and 11 kV. The sheet is then peeled from the ground plane and its residual charge density is measured. Results show that the residual charge equals the breakdown-limiting value, but its polarity depends on the surface potential acquired just prior to peeling. The results have relevance to studies of industrial webs and insulating sheets.

  5. The ATLAS semi-conductor tracker operation and performance

    International Nuclear Information System (INIS)

    Robinson, D.

    2013-01-01

    The Semi-Conductor Tracker (SCT) is a silicon strip detector and one of the key precision tracking devices in the Inner Detector of the ATLAS experiment at the CERN Large Hadron Collider (LHC). The SCT was installed and commissioned within ATLAS in 2007, and has been used to exploit fully the physics potential of the LHC since the first proton–proton collisions at 7 TeV were delivered in 2009. In this paper, its operational status throughout data taking up to the end of 2011 is presented, and its tracking performance is reviewed. -- Highlights: ► The operation and performance of the ATLAS Semi-Conductor Tracker (SCT) is reviewed. ► More than 99% of the SCT strips have remained operational in all data taking periods so far. ► Tracking performance indicators have met or exceeded design specifications. ► Radiation damage effects match closely expectations from delivered fluence.

  6. Chemical solution deposition: a path towards low cost coated conductors

    International Nuclear Information System (INIS)

    Obradors, X; Puig, T; Pomar, A; Sandiumenge, F; Pinol, S; Mestres, N; Castano, O; Coll, M; Cavallaro, A; Palau, A; Gazquez, J; Gonzalez, J C; Gutierrez, J; Roma, N; Ricart, S; Moreto, J M; Rossell, M D; Tendeloo, G van

    2004-01-01

    The achievement of low cost deposition techniques for high critical current YBa 2 Cu 3 O 7 coated conductors is one of the major objectives to achieve a widespread use of superconductivity in power applications. Chemical solution deposition techniques are appearing as a very promising methodology to achieve epitaxial oxide thin films at a low cost, so an intense effort is being carried out to develop routes for all chemical coated conductor tapes. In this work recent achievements will be presented towards the goal of combining the deposition of different type of buffer layers on metallic substrates based on metal-organic decomposition with the growth of YBa 2 Cu 3 O 7 layers using the trifluoroacetate route. The influence of processing parameters on the microstructure and superconducting properties will be stressed. High critical currents are demonstrated in 'all chemical' multilayers

  7. Current transfer between superconductor and normal layer in coated conductors

    International Nuclear Information System (INIS)

    Takacs, S

    2007-01-01

    The current transfer between superconducting stripes coated with normal layer is examined in detail. It is shown that, in present YBCO coated conductors with striations, a considerable amount of the current flowing in the normal layer is not transferred into the superconducting stripes. This effect also influences the eddy currents and the coupling currents between the stripes. The effective resistance for the coupling currents is calculated. The maximum allowable twist length of such a striated structure is given, which ensures lower losses than in the corresponding normal conductor of the same volume as the total YBCO cable (including substrate, buffer layer, superconductor and normal coating). In addition, a new simple method for determining the transfer resistance between superconducting and normal parts is proposed

  8. Hydrogen electrolysis using a NASICON solid protonic conductor

    Energy Technology Data Exchange (ETDEWEB)

    Gulens, J.; Longhurst, T.H.; Kuriakose, A.K.; Canaday, J.D.

    1988-09-01

    A protonic conductor based on a bonded NASICON disc has been used for hydrogen electrolysis at 300 K. Currents up to 200 mA can be passed through the disc, and the electrolysis proceeds with 100% current efficiency. The resistance of the ceramic is affected by its extent of hydration. Degradation and failure of the ceramic occurs at the cathode as a result of electrolysis.

  9. Intermediate Temperature Proton Conductors – Why and How

    OpenAIRE

    Li, Qingfeng; Aili, David; Jensen, Jens Oluf; Cleemann, Lars Nilausen

    2016-01-01

    The current technologies of fuel cells and electrolzers are based on ionic conducting electrolyte materials exclusively operational either in the low (20 - 200ºC) or high (600 - 1000ºC) temperature ranges. The intermediate temperature window, especially between 200 and 400 ºC, is still only represented by early fundamental material research for ionic electrolytes. Such materials, most likely based on proton conductors, are expected to bring a new generation of the technologies: fuel cells by ...

  10. What is a good conductor for metamaterials or plasmonics

    Directory of Open Access Journals (Sweden)

    Soukoulis Costas M.

    2015-04-01

    Full Text Available We review conducting materials like metals, conducting oxides and graphene for nanophotonic applications. We emphasize that metamaterials and plasmonic systems benefit from different conducting materials. Resonant metamaterials need conductors with small resistivity, since dissipative loss in resonant metamaterials is proportional to the real part of the resistivity of the conducting medium it contains. For plasmonic systems, one must determine the propagation length at a desired level of confinement to estimate the dissipative loss.

  11. Modelling the V-I characteristic of coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Rutter, N A [Department of Materials Science, University of Cambridge, Cambridge (United Kingdom); IRC in Superconductivity, Cavendish Laboratory, Cambridge (United Kingdom)]. E-mail: ruttern@ornl.gov; Glowacki, B A [Department of Materials Science, University of Cambridge, Cambridge (United Kingdom); IRC in Superconductivity, Cavendish Laboratory, Cambridge (United Kingdom)

    2001-09-01

    The critical current densities of coated conductor samples are limited by the presence of low-angle grain boundaries. These boundaries provide an obstacle to current flow, which is determined by their misorientation angle. The superconducting layer of a coated conductor tape may be considered as a network of grains linked together by grain boundaries through which the supercurrent must pass. Such a network has been investigated using a two-dimensional grain model. The three-dimensional orientations of grains in the superconducting network can be assigned randomly based on information obtained from EBSD and x-ray texture measurements. By assigning critical current values to boundaries based on their calculated misorientation, the overall J{sub c} of macroscopic modelled samples can then be calculated. This paper demonstrates how such a technique is applied using a small-scale, idealized sample grain structure in an applied magnetic field. The onset of dissipation at the critical current may be viewed in terms of the flow of the magnetic flux across the sample along high-angle grain boundaries when the critical current is first exceeded. Through such a consideration, the model may be further used to predict the current-voltage characteristic of the coated conductor sample around the superconducting transition. (author)

  12. MHD Modeling of Conductors at Ultra-High Current Density

    International Nuclear Information System (INIS)

    ROSENTHAL, STEPHEN E.; DESJARLAIS, MICHAEL P.; SPIELMAN, RICK B.; STYGAR, WILLIAM A.; ASAY, JAMES R.; DOUGLAS, M.R.; HALL, C.A.; FRESE, M.H.; MORSE, R.L.; REISMAN, D.B.

    2000-01-01

    In conjunction with ongoing high-current experiments on Sandia National Laboratories' Z accelerator, the authors have revisited a problem first described in detail by Heinz Knoepfel. Unlike the 1-Tesla MITLs of pulsed power accelerators used to produce intense particle beams, Z's disc transmission line (downstream of the current addition) is in a 100--1,200 Tesla regime, so its conductors cannot be modeled simply as static infinite conductivity boundaries. Using the MHD code MACH2 they have been investigating the conductor hydrodynamics, characterizing the joule heating, magnetic field diffusion, and material deformation, pressure, and velocity over a range of current densities, current rise-times, and conductor materials. Three purposes of this work are (1) to quantify power flow losses owing to ultra-high magnetic fields, (2) to model the response of VISAR diagnostic samples in various configurations on Z, and (3) to incorporate the most appropriate equation of state and conductivity models into the MHD computations. Certain features are strongly dependent on the details of the conductivity model

  13. High-field thermal transports properties of REBCO coated conductors

    CERN Document Server

    Bonura, M

    2015-01-01

    The use of REBCO coated conductors is envisaged for many applications, extending from power cables to high-field magnets. Whatever the case, thermal properties of REBCO tapes play a key role for the stability of superconducting devices. In this work, we present the first study on the longitudinal thermal conductivity (k) of REBCO coated conductors in magnetic fields up to 19 T applied both parallelly and perpendicularly to the thermal-current direction. Copper-stabilized tapes from six industrial manufacturers have been investigated. We show that zero-field k of coated conductors can be calculated with an accuracy of ‡ 15% from the residual resistivity ratio of the stabilizer and the Cu/non-Cu ratio. Measurements performed at high fields have allowed us to evaluate the consistency of the procedures generally used for estimating in-field k in the framework of the Wiedemann-Franz law from an electrical characterization of the materials. In-field data are intended to provide primary ingredients for the ...

  14. MHD Modeling of Conductors at Ultra-High Current Density

    International Nuclear Information System (INIS)

    Rosenthal, S.E.; Asay, J.R.; Desjarlais, M.P.; Douglas, M.R.; Frese, M.H.; Hall, C.A.; Morse, R.L.; Reisman, D.; Spielman, R.B.; Stygar, W.A.

    1999-01-01

    In conjunction with ongoing high-current experiments on Sandia National Laboratories' Z accelerator we have revisited a problem first described in detail by Heinz Knoepfel. MITLs of previous pulsed power accelerators have been in the 1-Tesla regime. Z's disc transmission line (downstream of the current addition) is in a 100-1200 Tesla regime, so its conductors cannot be modeled simply as static infinite conductivity boundaries. Using the MHD code MACH2 we have been investigating conductor hydrodynamics, characterizing the joule heating, magnetic field diffusion, and material deformation, pressure, and velocity over a range of current densities, current rise-times, and conductor materials. Three purposes of this work are ( 1) to quantify power flow losses owing to ultra-high magnetic fields, (2) to model the response of VISAR diagnostic samples in various configurations on Z, and (3) to incorporate the most appropriate equation of state and conductivity models into our MHD computations. Certain features are strongly dependent on the details of the conductivity model. Comparison with measurements on Z will be discussed

  15. Design principles for solid-state lithium superionic conductors.

    Science.gov (United States)

    Wang, Yan; Richards, William Davidson; Ong, Shyue Ping; Miara, Lincoln J; Kim, Jae Chul; Mo, Yifei; Ceder, Gerbrand

    2015-10-01

    Lithium solid electrolytes can potentially address two key limitations of the organic electrolytes used in today's lithium-ion batteries, namely, their flammability and limited electrochemical stability. However, achieving a Li(+) conductivity in the solid state comparable to existing liquid electrolytes (>1 mS cm(-1)) is particularly challenging. In this work, we reveal a fundamental relationship between anion packing and ionic transport in fast Li-conducting materials and expose the desirable structural attributes of good Li-ion conductors. We find that an underlying body-centred cubic-like anion framework, which allows direct Li hops between adjacent tetrahedral sites, is most desirable for achieving high ionic conductivity, and that indeed this anion arrangement is present in several known fast Li-conducting materials and other fast ion conductors. These findings provide important insight towards the understanding of ionic transport in Li-ion conductors and serve as design principles for future discovery and design of improved electrolytes for Li-ion batteries.

  16. Development of a Flexible Molecular Photocell With Up to 20% Conversion Efficiency

    National Research Council Canada - National Science Library

    Thampl, K

    2004-01-01

    .... The program was targeted at first realizing a molecular photovoltaic cell based on a dye sensitized nanocrystalline semiconductor film employing a hole conductor, a conducting polymer or a polymer...

  17. Selection of a cryostabilized Nb3Sn conductor cooling system for the large coil program

    International Nuclear Information System (INIS)

    Chi, J.W.H.; Murphy, J.H.; Jones, C.K.

    1977-01-01

    The Large Coil Project (LCP) is a program to design, fabricate and test relatively large superconducting toroidal field coils for tokamak fusion reactor applications. Some basic requirements that affect the conductor design are cryostabilization, 8 tesla peak magnetic field, and a specified maximum refrigeration load. The engineering considerations that led to the selection of a forced flow supercritical helium-cooled cable conductor are described. Comparisons of forced flow supercritical helium cooled cable conductors with pool boiling cooled monolithic conductors were made with regard to a number of factors such as the thermal capacity of the coolant, the thermal design margins, propensity for conductor normalization, predictability of the thermal-flow performance, controllability of the cooling conditions, etc. It was concluded that, although there exists a number of design uncertainties and engineering problems, forced flow supercritical helium cooled conductors can provide a far more reliable coil design than the pool boiling monolithic concept. The design of a cryostabilized Nb 3 Sn hollow cabled conductor involved detailed considerations of the need for fully transposed conductor strands, the nonuniform void and helium flow distributions, heat transfer from the twisted conductor strands, and helium flow rate and pump work requirements. The uncertainties in the design are discussed and the specifications of a reference Nb 3 Sn conductor concept that meets the design requirements and constraints are presented

  18. Conductors for commercial MRI magnets beyond NbTi: requirements and challenges

    Science.gov (United States)

    Parizh, Michael; Lvovsky, Yuri; Sumption, Michael

    2017-01-01

    Magnetic resonance imaging (MRI), a powerful medical diagnostic tool, is the largest commercial application of superconductivity. The superconducting magnet is the largest and most expensive component of an MRI system. The magnet configuration is determined by competing requirements including optimized functional performance, patient comfort, ease of siting in a hospital environment, minimum acquisition and lifecycle cost including service. In this paper, we analyze conductor requirements for commercial MRI magnets beyond traditional NbTi conductors, while avoiding links to a particular magnet configuration or design decisions. Potential conductor candidates include MgB2, ReBCO and BSCCO options. The analysis shows that no MRI-ready non-NbTi conductor is commercially available at the moment. For some conductors, MRI specifications will be difficult to achieve in principle. For others, cost is a key barrier. In some cases, the prospects for developing an MRI-ready conductor are more favorable, but significant developments are still needed. The key needs include the development of, or significant improvements in: (a) conductors specifically designed for MRI applications, with form-fit-and-function readily integratable into the present MRI magnet technology with minimum modifications. Preferably, similar conductors should be available from multiple vendors; (b) conductors with improved quench characteristics, i.e. the ability to carry significant current without damage while in the resistive state; (c) insulation which is compatible with manufacturing and refrigeration technologies; (d) dramatic increases in production and long-length quality control, including large-volume conductor manufacturing technology. In-situ MgB2 is, perhaps, the closest to meeting commercial and technical requirements to become suitable for commercial MRI. Conductor technology is an important, but not the only, issue in introduction of HTS/MgB2 conductor into commercial MRI magnets. These

  19. Exploring the limits of a very large Nb3Sn conductor: the 80 kA conductor of the ITER toroidal field model coil

    International Nuclear Information System (INIS)

    Duchateau, J.L.; Ciazynski, D.; Guerber, O.; Park, S.H.; Zani, L.

    2003-01-01

    In Phase II experiment of the International Thermonuclear Experimental Reactor (ITER) Toroidal Field Model Coil (TFMC) the operation limits of its 80 kA Nb 3 Sn conductor were explored. To increase the magnetic field on the conductor, the TFMC was tested in presence of another large coil: the EURATOM-LCT coil. Under these conditions the maximum field reached on the conductor, was around 10 tesla. This exploration has been performed at constant current, by progressively increasing the coil temperature and monitoring the coil voltage drop in the current sharing regime. Such an operation was made possible thanks to the very high stability of the conductor. The aim of these tests was to compare the critical properties of the conductor with expectations and assess the ITER TF conductor design. These expectations are based on the documented critical field and temperature dependent properties of the 720 superconducting strands which compose the conductor. In addition the conductor properties are highly dependent on the strain, due to the compression appearing on Nb 3 Sn during the heat treatment of the pancakes and related to the differential thermal compression between Nb 3 Sn and the stainless steel jacket. No precise model exists to predict this strain, which is therefore the main information, which is expected from these tests. The method to deduce this strain from the different tests is presented, including a thermalhydraulic analysis to identify the temperature of the critical point and a careful estimation of the field map across the conductor. The measured strain has been estimated in the range -0.75% to -0.79 %. This information will be taken into account for ITER design and some adjustment of the ITER conductor design is under examination. (authors)

  20. Transport ac losses in Bi-2223 multifilamentary tapes - conductor materials aspect

    Energy Technology Data Exchange (ETDEWEB)

    Glowacki, B A [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge BC2 3QZ (United Kingdom); Majoros, M [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Institute of Electrical Engineering, SAS, Bratislava (Slovakia)

    2000-05-01

    Transport ac losses in technical superconductors based on Bi-2223 tape material are influenced by many parameters. The major factors that define the ac performance of such conductors are the following: the size and number of filaments, their geometrical arrangement in the cross-section of the conductor, the twist pitch length, the resistivity of the matrix, the presence of oxide barriers around the filaments and deformation procedures such as sequential pressing or rolling followed by appropriate thermal treatment. In the present paper the above aspects are addressed from the viewpoint of the materials science of technical conductor design. Transport ac losses at power frequencies in different types of Bi-2223 conductor are presented and analysed. The results of conductor design analysis with respect to the coexistence of the superconductor with other materials in the conductor structure are presented. New concepts for minimization of the transport ac losses are discussed in detail. (author)

  1. A Boundary Element Solution to the Problem of Interacting AC Fields in Parallel Conductors

    Directory of Open Access Journals (Sweden)

    Einar M. Rønquist

    1984-04-01

    Full Text Available The ac fields in electrically insulated conductors will interact through the surrounding electromagnetic fields. The pertinent field equations reduce to the Helmholtz equation inside each conductor (interior problem, and to the Laplace equation outside the conductors (exterior problem. These equations are transformed to integral equations, with the magnetic vector potential and its normal derivative on the boundaries as unknowns. The integral equations are then approximated by sets of algebraic equations. The interior problem involves only unknowns on the boundary of each conductor, while the exterior problem couples unknowns from several conductors. The interior and the exterior problem are coupled through the field continuity conditions. The full set of equations is solved by standard Gaussian elimination. We also show how the total current and the dissipated power within each conductor can be expressed as boundary integrals. Finally, computational results for a sample problem are compared with a finite difference solution.

  2. Loss and Inductance Investigations in a 4-layer Superconducting Prototype Cable Conductor

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Olsen, Søren Krüger; Kühle (fratrådt), Anders Van Der Aa

    1999-01-01

    One important issue in the design and optimization of a superconducting cable conductor is the control of the current distribution between single tapes and layers. This presentation is based on a number of experiments performed on a 4-layer three meter long prototype superconducting cable conductor......-losses are measured as a function of transport current and a given current distribution and compared with the monoblock model. Recommendations for design of future cable conductor prototypes are given....

  3. Estimation of Equivalent Thermal Conductivity for Impregnated Electrical Windings Formed from Profiled Rectangular Conductors

    OpenAIRE

    Ayat, Sabrina S; Wrobel, Rafal; Goss, James; Drury, David

    2016-01-01

    In order to improve accuracy and reduce model setting-up, and solving time in thermal analysis of electrical machines, transformers and wound passive components, the multi-material winding region is frequently homogenised. The existing winding homogenization techniques are predo-minantly focused on winding constructions with round conductors, where thermal conductivity across conductors is usually assumed to be isotropic. However, for the profiled rectangular conductors that assumption is no ...

  4. Studies on advanced superconductors for fusion device. Pt. 1. Present status of Nb3Sn conductors

    International Nuclear Information System (INIS)

    Tachikawa, Kyoji; Yamamoto, Junya

    1996-03-01

    Nb 3 Sn conductors have been developed with great expectation as an advanced high-field superconductor to be used in fusion devices of next generation. Furthermore, Nb 3 Sn conductors are being developed for NMR magnet and superconducting generator as well as for cryogen-free superconducting magnet. A variety of fabrication procedures, such as bronze process, internal tin process and Nb tube method, have been developed based on the diffusion reaction. Recently, Nb 3 Sn conductors with ultra-thin filaments have been fabricated for AC use. Both high-field and AC performances of Nb 3 Sn conductors have been significantly improved by alloying addition. The Ti-doped Nb 3 Sn conductor has generated 21.5T at 1.8K operation. This report summarizes manufacturing procedures, superconducting performances and applications of Nb 3 Sn conductors fabricated through different processes in different countries. More detailed subjects included in this report are high-field properties, AC properties, conductors for fusion with large current capacities, stress-strain effect and irradiation effect as well as standardization of critical current measurement method regarding to Nb 3 Sn conductors. Comprehensive grasp on the present status of Nb 3 Sn conductors provided by this report will act as a useful data base for the future planning of fusion devices. (author). 172 refs

  5. Investigation of the influence of heat transfer on screen printed textile conductor

    Science.gov (United States)

    Kazani, I.; De Mey, G.; Hertleer, C.; Guxho, G.; Van Langenhove, L.

    2017-10-01

    Two different textile substrates were screen printed with silver-based inks in order to be electrically conductive. In every textile four conductors were printed with different widths in order to investigate the influence of heat transfer on each conductor. This was done, by using the thermo graphic camera and through the evaluation of each conductor’s profile. It was found that the conductors printed on the white textile had higher values of heat transfer compared to the other conductors printed on the dark textiles.

  6. Solderability study of RABiTS-based YBCO coated conductors

    International Nuclear Information System (INIS)

    Zhang Yifei; Duckworth, Robert C.; Ha, Tam T.; Gouge, Michael J.

    2011-01-01

    Study examines the implication of solder and flux selection in YBCO splice joints. Focus is on commercially available RABiTS-based YBCO coated conductors. Solderability varied with solder and flux for three different stabilizations tested. Resistivity of stabilizer was dominant factor in splice joint resistance. Solder materials affected splice joint resistance when solderability was poor. The solderability of commercially available YBa 2 Cu 3 O 7-x (YBCO) coated conductors that were made from Rolling Assisted Biaxially Textured Substrates (RABiTS)-based templates was studied. The coated conductors, also known as second-generation (2G) high temperature superconductor (HTS) wires (in the geometry of flat tapes about 4 mm wide), were laminated with copper, brass, or stainless steel strips as stabilizers. To understand the factors that influence their solderability, surface profilometry and scanning electron microscopy were used to characterize the wire surfaces. The solderability of three solders, 52In48Sn, 67Bi33In, and 100In (wt.%), was evaluated using a standard test (IPC/ECA J-STD-002) and with two different commercial fluxes. It was found that the solderability varied with the solder and flux but the three different wires showed similar solderability for a fixed combination of solder and flux. Solder joints of the 2G wires were fabricated using the tools and the procedures recommended by the HTS wire manufacturer. The solder joints were made in a lap-joint geometry and with the superconducting sides of the two wires face-to-face. The electrical resistances of the solder joints were measured at 77 K, and the results were analyzed to qualify the soldering materials and evaluate the soldering process. It was concluded that although the selection of soldering materials affected the resistance of a solder joint, the resistivity of the stabilizer was the dominant factor.

  7. Preparation of the ITER Poloidal Field Conductor Insert (PFCI) test

    International Nuclear Information System (INIS)

    Zanino, R.; Egorov, S.; Kim, K.; Martovetsky, N.; Nunoya, Y.; Okuno, K.; Salpietro, E.; Sborchia, C.; Takahashi, Y.; Weng, P.; Bangasco, M.; Savoldi Richard, L.; Polak, M.; Formisano, A.; Zapretilina, E.; Shikov, A.; Vedernikov, G.; Ciazynski, D.; Zani, L.; Muzzi, L.; Ricci, M.; Deela Corte, A.; Sugimoto, M.; Hamada, K.; Portone, A.; Hurd, F.; Mitchell, N.; Nijhuis, A.; Ilyin, Y.

    2004-01-01

    The Poloidal Field Conductor Insert (PFCI) of the International Thermonuclear Experimental Reactor (ITER) has been designed in Europe and is being manufactured at Tesla Engineering, UK, in the frame of a Task Agreement with the ITER International Team. Completion of the PFCI is expected at the beginning of 2005. Then, the coil shall be shipped to JAERI Naka, Japan, and inserted into the bore of the ITER Central Solenoid Model Coil, where it should be tested in 2005 to 2006. The PFCI consists of a NbTi dual-channel conductor, almost identical to the ITER PF1 and PF6 design, about 45 m long, with a 50 mm thick square stainless steel jacket, wound in a single-layer solenoid. It should carry up to 50 kA in a field of about 6 T, and it will be cooled by supercritical He at around 4.5 K and 0.6 MPa. An intermediate joint, representative of the ITER PF joints and located at relatively high field, will be an important new item in the test configuration with respect to the previous ITER Insert Coils. The PFCI will be fully instrumented with inductive and resistive heaters, as well as with voltage taps, Hall probes, pick-up coils, temperature sensors, pressure taps, strain and displacement sensors. The test program shall be aimed at DC and pulsed performance assessment of conductor and intermediate joint, AC loss measurement, stability and quench propagation, thermalhydraulic characterization. Here we give an overview of the preparatory work towards the test, including a review of the coil manufacturing and of the available instrumentation, a discussion of the most likely test program items, and a presentation of the supporting modeling and characterization work performed so far. (authors)

  8. Laser direct fabrication of silver conductors on glass boards

    International Nuclear Information System (INIS)

    Li Xiangyou; Zeng Xiaoyan; Li Huiling; Qi Xiaojing

    2005-01-01

    Laser micro-cladding has been used to fabricate metal conductors, according to a designed electronic circuit, directly onto glass boards which had been coated with a silver-containing electronic paste. The electronic pastes, composed of silver powders, inorganic binders and organic medium, thus formed the conductive metal pattern (i.e. electric circuit) along the path of the laser allowing the rest of the layer to be removed subsequently by an organic solvent. Firing in a furnace at 600 deg. C resulted in conductive lines with resistivity of about 10 -5 Ω cm and with adhesive strength of the order of magnitude of megapascals

  9. Specific features of the thermodynamics of superionic conductors

    International Nuclear Information System (INIS)

    Gurevich, Yu.Ya.; Kharkats, Yu.I.

    1982-01-01

    A review of theoretical and experimental investigations devoted to a study of thermodynamic aspects of the superionic conductivity phenomena for the recent decade is presented. A relation between a superionic conductivity and the disordering of one of the crystal sublattices, the phase transitions of the disordering caused by the point defects interaction, the mechanism of polymorphic transitions conjugated with a partial disordering are considered. The effect of an abrupt change of the ionic conductivity induced by electric field, the thermodynamics of the domain states in superionic conductors and the influence of pressure on phase transitions and ionic conductivity are analyzed

  10. The ATLAS Semi-Conductor Tracker Operation and Performance

    CERN Document Server

    Robinson, D; The ATLAS collaboration

    2012-01-01

    The Semi-Conductor Tracker (SCT), is a silicon strip detector and one of the key precision tracking devices in the Inner Detector of the ATLAS experiment at the CERN Large Hadron Collider (LHC). The SCT was installed and commissioned within ATLAS in 2007, and has been has been used to fully exploit the physics potential of the LHC since the first proton-proton collisions at 7 TeV were delivered in 2009. In this paper, its operational status throughout data taking up to the end of 2011 is presented, and its tracking performance is reviewed.

  11. Method for deposition of a conductor in integrated circuits

    Science.gov (United States)

    Creighton, J. Randall; Dominguez, Frank; Johnson, A. Wayne; Omstead, Thomas R.

    1997-01-01

    A method is described for fabricating integrated semiconductor circuits and, more particularly, for the selective deposition of a conductor onto a substrate employing a chemical vapor deposition process. By way of example, tungsten can be selectively deposited onto a silicon substrate. At the onset of loss of selectivity of deposition of tungsten onto the silicon substrate, the deposition process is interrupted and unwanted tungsten which has deposited on a mask layer with the silicon substrate can be removed employing a halogen etchant. Thereafter, a plurality of deposition/etch back cycles can be carried out to achieve a predetermined thickness of tungsten.

  12. The quantum flux in quasis one-dimensional conductors

    International Nuclear Information System (INIS)

    Ventura, J.

    1989-01-01

    A method is presented which quantizes electromagnetic fluxes directly in flux space. It is based on the commutation law [φ B , φ E ] = i, where φ B is the magnetic flux, and φ E the longitudinal electric flux of a quasi one-dimensional conductor. The relevance of such a method for the description of the quantized Hall plateaus is discussed. In a second step, the polarization electric flux is introduced, together with a method for quantization of hybrid variables formed with pure electromagnetic fluxes plus electronic variables. (author) [pt

  13. Flux line lattice in type II super conductors

    International Nuclear Information System (INIS)

    Manindra Kumar; Singh, Arun Kumar; Surendra Kumar

    2003-01-01

    The shear modules C 66 of the flux line lattice in type II super conductors can be obtained from a two body interaction between the flux lines even at large inductions B ∼ HC 2 . The potential is composed of a repulsive and an attractive part and has a range diverging at HC 2 . An explicit expression for the Ginzberg-Landau C 66 is given for arbitrary B and k' (G-L parameter). The graph for C 66 exhibits the expected maximum at a certain value of b. (author)

  14. Magnet and conductor developments for the Mirror Fusion Program

    International Nuclear Information System (INIS)

    Cornish, D.N.

    1981-01-01

    The conductor development and the magnet design and construction for the MFTF are described. Future plans for the Mirror Program and their influence on the associated superconductor development program are discussed. Included is a summary of the progress being made to develop large, high-field, multifilamentary Nb 3 Sn superconductors and the feasibility of building a 12-T yin-yang set of coils for the machine to follow MFTF. In a further look into the future, possible magnetic configurations and requirements for mirror reactors are surveyed

  15. Application of the Lifshitz Theory to Poor Conductors

    International Nuclear Information System (INIS)

    Svetovoy, Vitaly B.

    2008-01-01

    The Lifshitz formula for dispersive forces is generalized to the materials, which cannot be described with the local dielectric response. The principal nonlocality of poor conductors is related to the finite screening length of the penetrating field and collisional relaxation; at low temperatures the role of collisions plays the Landau damping. Spatial dispersion makes the theory self-consistent. Our predictions are compared with the recent experiment. It is demonstrated that at low temperatures Casimir-Lifshitz entropy disappears as T in the case of degenerate plasma and as T 2 for the nondegenerate one

  16. Quench propagation in coated conductors for fault current limiters

    International Nuclear Information System (INIS)

    Roy, F.; Perez, S.; Therasse, M.; Dutoit, B.; Sirois, F.; Decroux, M.; Antognazza, L.

    2009-01-01

    A fundamental understanding of the quench phenomenon is crucial in the future design and operation of high temperature superconductors based fault current limiters. The key parameter that quantifies the quenching process in superconductors is the normal zone propagation (NZP) velocity, which is defined as the speed at which the normal zone expands into the superconducting volume. In the present paper, we used numerical models developed in our group recently to investigate the quench propagation in coated conductors. With our models, we have shown that the NZP in these tapes depends strongly on the substrate properties.

  17. Computer simulation of multiple stability regions in an internally cooled superconducting conductor and of helium replenishment in a bath-cooled conductor

    International Nuclear Information System (INIS)

    Turner, L.R.; Shindler, J.

    1984-09-01

    For upcoming fusion experiments and future fusion reactors, superconducting magnetic have been chosen or considered which employ cooling by pool-boiling HeI, by HeII, and by internally flowing HeI. The choice of conductor and cooling method should be determined in part by the response of the magnet to sudden localized heat pulses of various magnitudes. The paper describes the successful computer simulation of multiple stability in internally cooled conductors, as observed experimentally, using the computer code SSICC. It also describes the modeling of helium replenishment in the cooling channels of a bath-cooled conductor, using the computer code TASS

  18. AC loss, interstrand resistance and mechanical properties of prototype EU DEMO TF conductors up to 30 000 load cycles

    Science.gov (United States)

    Yagotintsev, K.; Nijhuis, A.

    2018-07-01

    Two prototype Nb3Sn cable-in-conduit conductors conductors were designed and manufactured for the toroidal field (TF) magnet system of the envisaged European DEMO fusion reactor. The AC loss, contact resistance and mechanical properties of two sample conductors were tested in the Twente Cryogenic Cable Press under cyclic load up to 30 000 cycles. Though both conductors were designed to operate at 82 kA in a background magnetic field of 13.6 T, they reflect different approaches with respect to the magnet winding pack assembly. The first approach is based on react and wind technology while the second is the more common wind and react technology. Each conductor was tested first for AC loss in virgin condition without handling. The impact of Lorentz load during magnet operation was simulated using the cable press. In the press each conductor specimen was subjected to transverse cyclic load up to 30 000 cycles in liquid helium bath at 4.2 K. Here a summary of results for AC loss, contact resistance, conductor deformation, mechanical heat production and conductor stiffness evolution during cycling of the load is presented. Both conductors showed similar mechanical behaviour but quite different AC loss. In comparison with previously tested ITER TF conductors, both DEMO TF conductors possess very low contact resistance resulting in high coupling loss. At the same time, load cycling has limited impact on properties of DEMO TF conductors in comparison with ITER TF conductors.

  19. Fully filamentized HTS coated conductor via striation and selective electroplating

    Energy Technology Data Exchange (ETDEWEB)

    Kesgin, Ibrahim; Majkic, Goran [Department of Mechanical Engineering and Texas Center for Superconductivity, University of Houston, Houston, TX 77204 (United States); Selvamanickam, Venkat, E-mail: selva@uh.edu [Department of Mechanical Engineering and Texas Center for Superconductivity, University of Houston, Houston, TX 77204 (United States)

    2013-03-15

    Highlights: ► Fully-filamentized coated conductor with 13-fold reduction in ac losses. ► Selective electroplating for filamentization of thick copper stabilizer. ► A twofold decrease in ac loss by filamentization of copper stabilizer. ► Absence of appreciable coupling loss contribution from electroplating. -- Abstract: A simple, cost-effective method involving top-down mechanical scribing, oxidation and bottom-up electroplating has been successfully developed to fabricate fully filamentized HTS coated conductors. The copper stabilizer layer is selectively electroplated on the superconducting filaments while the striations remain copper-free due to the formation of a resistive oxide layer in between filaments by oxidation of the striated grooves at elevated temperature in oxygen atmosphere. Magnetization AC loss measurements, performed in a frequency range of 45–500 Hz at 77 K, confirmed the expected N-fold reduction in AC loss of the filamentized tapes with no significant degradation in critical current beyond that due to the material removal from the striations (N – number of filaments). A considerable reduction in coupling AC loss was observed after high temperature annealing/oxidation of the striated tapes. Furthermore, a significant reduction in eddy current loss was achieved with selective copper electroplating, as evidenced by analyzing the field and frequency dependence of magnetization AC loss, as well as by comparing the AC loss performance of striated samples to that of non-striated samples after electroplating of copper stabilizer.

  20. Mutual capacitance of liquid conductors in deformable tactile sensing arrays

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bin [Electrical and Computer Engineering Department, Drexel University, Philadelphia, Pennsylvania 19104 (United States); Fontecchio, Adam K. [Electrical and Computer Engineering and Materials Science and Engineering Departments, Drexel University, Philadelphia, Pennsylvania 19104 (United States); Visell, Yon [Electrical and Computer Engineering Department, Media Arts and Technology, California NanoSystems Institute, University of California, Santa Barbara, California 93106 (United States)

    2016-01-04

    Advances in highly deformable electronics are needed in order to enable emerging categories of soft computing devices ranging from wearable electronics, to medical devices, and soft robotic components. The combination of highly elastic substrates with intrinsically stretchable conductors holds the promise of enabling electronic sensors that can conform to curved objects, reconfigurable displays, or soft biological tissues, including the skin. Here, we contribute sensing principles for tactile (mechanical image) sensors based on very low modulus polymer substrates with embedded liquid metal microfluidic arrays. The sensors are fabricated using a single-step casting method that utilizes fine nylon filaments to produce arrays of cylindrical channels on two layers. The liquid metal (gallium indium alloy) conductors that fill these channels readily adopt the shape of the embedding membrane, yielding levels of deformability greater than 400%, due to the use of soft polymer substrates. We modeled the sensor performance using electrostatic theory and continuum mechanics, yielding excellent agreement with experiments. Using a matrix-addressed capacitance measurement technique, we are able to resolve strain distributions with millimeter resolution over areas of several square centimeters.

  1. Thermoelectric power in ionic and electronic mixed conductors

    Energy Technology Data Exchange (ETDEWEB)

    Kamata, Masahiro; Jin-nouchi, Kenji; Esaka, Takao [Tottori Univ. (Japan). Faculty of Engineering

    1996-08-01

    In order to study the thermoelectric property of the oxide ionic and electronic mixed conductor of 10 mol% CaO-doped CeO{sub 2} (CDC), a new type of thermocell was prepared, in which platinum electrodes were embedded in the tube-type sample to diminish the large temperature gradient over the electrodes due to the local heat radiation from heating furnace. Using this thermocell, reproducible data were obtained. The thermoelectric power measured in CDC under various oxygen atmospheres (Po{sub 2}) from 1.0 to about 10{sup -15} atm showed that the sign of Seebeck coefficients changed from minus to plus. This variation of Seebeck coefficients vs. Po{sub 2} was well interpreted by considering that (1) the thermoelectric power could be a driving force to make actual and electrochemical oxygen transfer in the mixed conductor and (2) the electrode processes had limiting rates due to slow oxygen diffusion (or oxygen gas exhaustion at the cathode and evolution at the anode). (author)

  2. Fully filamentized HTS coated conductor via striation and selective electroplating

    International Nuclear Information System (INIS)

    Kesgin, Ibrahim; Majkic, Goran; Selvamanickam, Venkat

    2013-01-01

    Highlights: ► Fully-filamentized coated conductor with 13-fold reduction in ac losses. ► Selective electroplating for filamentization of thick copper stabilizer. ► A twofold decrease in ac loss by filamentization of copper stabilizer. ► Absence of appreciable coupling loss contribution from electroplating. -- Abstract: A simple, cost-effective method involving top-down mechanical scribing, oxidation and bottom-up electroplating has been successfully developed to fabricate fully filamentized HTS coated conductors. The copper stabilizer layer is selectively electroplated on the superconducting filaments while the striations remain copper-free due to the formation of a resistive oxide layer in between filaments by oxidation of the striated grooves at elevated temperature in oxygen atmosphere. Magnetization AC loss measurements, performed in a frequency range of 45–500 Hz at 77 K, confirmed the expected N-fold reduction in AC loss of the filamentized tapes with no significant degradation in critical current beyond that due to the material removal from the striations (N – number of filaments). A considerable reduction in coupling AC loss was observed after high temperature annealing/oxidation of the striated tapes. Furthermore, a significant reduction in eddy current loss was achieved with selective copper electroplating, as evidenced by analyzing the field and frequency dependence of magnetization AC loss, as well as by comparing the AC loss performance of striated samples to that of non-striated samples after electroplating of copper stabilizer

  3. A dendrite-suppressing composite ion conductor from aramid nanofibres.

    Science.gov (United States)

    Tung, Siu-On; Ho, Szushen; Yang, Ming; Zhang, Ruilin; Kotov, Nicholas A

    2015-01-27

    Dendrite growth threatens the safety of batteries by piercing the ion-transporting separators between the cathode and anode. Finding a dendrite-suppressing material that combines high modulus and high ionic conductance has long been considered a major technological and materials science challenge. Here we demonstrate that these properties can be attained in a composite made from Kevlar-derived aramid nanofibres assembled in a layer-by-layer manner with poly(ethylene oxide). Importantly, the porosity of the membranes is smaller than the growth area of the dendrites so that aramid nanofibres eliminate 'weak links' where the dendrites pierce the membranes. The aramid nanofibre network suppresses poly(ethylene oxide) crystallization detrimental for ion transport, giving a composite that exhibits high modulus, ionic conductivity, flexibility, ion flux rates and thermal stability. Successful suppression of hard copper dendrites by the composite ion conductor at extreme discharge conditions is demonstrated, thereby providing a new approach for the materials engineering of solid ion conductors.

  4. ATLAS SemiConductor Tracker Operation and Performance

    CERN Document Server

    Tojo, J; The ATLAS collaboration

    2011-01-01

    The SemiConductor Tracker (SCT), comprising of silicon micro-strip detectors is one of the key precision tracking devices in the ATLAS Inner Detector. ATLAS is one of the experiments at CERN LHC. The completed SCT is in very good shapes with 99.3% of the SCT’s 4088 modules (a total of 6.3 million strips) are operational. The noise occupancy and hit efficiency exceed the design specifications. In the talk the current status of the SCT will be reviewed. We will report on the operation of the detector, its performance and observed problems, with stress on the sensor and electronics performance. In December 2009 the ATLAS experiment at the CERN Large Hadron Collider (LHC) recorded the first proton-proton collisions at a centre-of-mass energy of 900 GeV and this was followed by the unprecedented energy of 7 TeV in March 2010. The Semi- Conductor Tracker (SCT) is the key precision tracking device in ATLAS, made from silicon micro-strip detectors processed in the planar p-in-n technology. The signals from the stri...

  5. Mechanical characterization and assessment of the CMS conductor

    CERN Document Server

    Sequeira-Lopes-Tavares, S; Desirelli, Alberto; Sgobba, Stefano; Horváth, I L

    2000-01-01

    The Compact Muon Solenoid (CMS) is one of the experiments which are being designed in the framework of the Large Hadron Collider (LHC) project at CERN. The design field of the CMS magnet is 4 T, the magnetic length is 12.5m and the free aperture is 6 m in diameter. This is achieved with a 4 layer and 5 module superconducting Al stabilized coil, resulting into 20 lengths of conductor of 2.5 km each, energized at a nominal current of 20 kA at 4.5 K. One of the unique features of this thin solenoid is an Al-stabilized conductor reinforced by an Al-alloy. An extensive characterization of mechanical properties at room temperature and 4.2 K has been carried out in order to define the most appropriate alloy and temper for the reinforcement. The effect of the coil curing cycle on the alloy properties has been taken into account. This paper summarizes the main results of these tests. (7 refs).

  6. Duality and reciprocity of fluctuation-dissipation relations in conductors.

    Science.gov (United States)

    Reggiani, Lino; Alfinito, Eleonora; Kuhn, Tilmann

    2016-09-01

    By analogy with linear response, we formulate the duality and reciprocity properties of current and voltage fluctuations expressed by Nyquist relations, including the intrinsic bandwidths of the respective fluctuations. For this purpose, we individuate total-number and drift-velocity fluctuations of carriers inside a conductor as the microscopic sources of noise. The spectral densities at low frequency of the current and voltage fluctuations and the respective conductance and resistance are related in a mutually exclusive way to the corresponding noise source. The macroscopic variances of current and voltage fluctuations are found to display a dual property via a plasma conductance that admits a reciprocal plasma resistance. Analogously, the microscopic noise sources are found to obey a dual property and a reciprocity relation. The formulation is carried out in the frame of the grand canonical (for current noise) and canonical (for voltage noise) ensembles, and results are derived that are valid for classical as well as degenerate statistics, including fractional exclusion statistics. The unifying theory so developed sheds new light on the microscopic interpretation of dissipation and fluctuation phenomena in conductors. In particular, it is proven that for fermions, as a consequence of the Pauli principle, nonvanishing single-carrier velocity fluctuations at zero temperature are responsible for diffusion but not for current noise, which vanishes in this limit.

  7. Internal pressure effects in the AIRCO-LCT conductor sheath

    International Nuclear Information System (INIS)

    Luton, J.N.; Clinard, J.A.; Lue, J.W.; Gray, W.H.; Summers, L.T.; Kershaw, R.

    1985-01-01

    The large Nb 3 Sn superconducting test coil produced by Westinghouse Electric Corporation for the international Large Coil Task (LCT) utilizes a conductor composed of cabled multifilamentary strands immersed in flowing supercritical helium contained by a square structural sheath made of the high-strength stainless alloy JBX-75. Peak pressures of a few hundred atmospheres are predicted to occur during quench, and measurement of these pressures seems feasible only through penetrations of the sheath wall. Fully processed short lengths of conductor were taken from production ends, fitted with pressure taps and strain gauges, and pressurized with helium gas. Failure, at 1000 atm at liquid nitrogen temperature, was by a catastrophic splitting of the sheath at a corner. Strain measurements and burst pressure agreed with elastic-plastic finite element stress calculations made for the sheath alone. Neither the production seam weld nor the pressure tap penetrations or their fillet welds contributed to the failure, although the finite element calculations show that these areas were also highly stressed, and examination of the failed sample showed that the finite welds were of poor quality. Failure was by tensile overload, with no evidence of fatigue

  8. A Systematic Inventory of Motives for Becoming an Orchestra Conductor: A Preliminary Study

    Science.gov (United States)

    Makris, Ioannis; Mullet, Etienne

    2009-01-01

    The study examined the various motives (reasons) that may have led an individual to become an orchestra conductor interpreting classical works, using Apter's (2001) Metamotivational Theory framework. Questionnaires derived from the theory, consisting of 92 possible motives for becoming an orchestra conductor, were presented to 101 orchestra…

  9. Powder-in-Tube (PIT) Nb3Sn conductors for high-field magnets

    NARCIS (Netherlands)

    Lindenhovius, J.H.; Hornsveld, E.M.; den Ouden, A.; Wessel, Wilhelm A.J.; ten Kate, Herman H.J.

    2000-01-01

    New Nb3Sn conductors, based on the powder-in-tube (PIT) process, have been developed for application in accelerator magnets and high-field solenoids. For application in accelerator magnets, SMI has developed a binary 504 filament PIT conductor by optimizing the manufacturing process and adjustment

  10. Power line conductor icing prevention by the Joule effect : parametric analysis and energy requirements

    Energy Technology Data Exchange (ETDEWEB)

    Peter, Z.; Farzaneh, M.; Kiss, L.I. [Quebec Univ., Chicoutimi, PQ (Canada). Industrial Chair on Atmospheric Icing of Power Network Equipment

    2005-07-01

    A mathematical model to calculate the minimum current intensity needed to prevent potentially damaging ice accretion on power line conductors was presented. The influence of atmospheric parameters such as wind speed, air temperature and liquid water were considered. Energy analysis was developed for an aluminum and steel reinforced conductor with circular cylindrical wire and concentric layers. Atmospheric parameters and the duration of the freezing conditions were considered with reference to the Joule effect. The model was then compared with experiments and simulations performed at an icing wind tunnel and in a climate room. It was determined that the equivalent thermal conductivity of the conductor should be assessed to identify the temperature distribution in the power line conductor. The radial component of the thermal conductivity was estimated on the basis of experiments performed in the wind tunnel, which provided a good estimation of the equivalent thermal conductivity and overall heat transfer coefficient around the stranded conductor. Experimental results were compared with values obtained from theoretically equivalent conductivity models. It was observed that the convective heat transfer coefficients around stranded conductors were higher than around smooth cylinders, and that the mathematical calculations slightly overestimated the wind tunnel measurements due to difficulties in estimating the wetted surface and the overall convection heat transfer coefficient around a stranded conductor. The typical range for the equivalent thermal conductivity of stranded conductors was also presented. 13 refs., 1 tab., 11 figs.

  11. The Connoisseurship of Conducting: A Qualitative Study of Exemplary Wind Band Conductors

    Science.gov (United States)

    Barry, Nancy; Henry, Daniel

    2015-01-01

    This study aimed to gain an in-depth perspective through examining how the conducting pedagogy of three selected exemplary high school and college instrumental music conductors function within the context of an actual rehearsal. A typical rehearsal was video recorded, followed by a "think-aloud" session in which the conductor viewed the…

  12. An experimental method to determine the electrostatic field enhancement factor of a practical conductor surface

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson; Crichton, George C

    1989-01-01

    A method of determining the field enhancement factor of a practical conductor is presented. The method is developed from a modified theory of discharge onset in a gaseous medium. This modification incorporates the influence of conductor surface roughness. Onset data from an experimental study...

  13. Synthesis and Characterization of Ethylenedithio-MPTTF-PTM Radical Dyad as a Potential Neutral Radical Conductor

    DEFF Research Database (Denmark)

    Souto, Manuel; Bendixen, Dan; Jensen, Morten

    2016-01-01

    During the last years there has been a high interest in the development of new purely-organic single-component conductors. Very recently, we have reported a new neutral radical conductor based on the perchlorotriphenylmethyl (PTM) radical moiety linked to a monopyrrolo-tetrathiafulvalene (MPTTF...

  14. The Virtual Conductor: Learning and Teaching about Music, Performing, and Conducting

    NARCIS (Netherlands)

    Nijholt, Antinus; Reidsma, Dennis; Ebbers, Rob; ter Maat, Mark

    2008-01-01

    The Virtual Conductor is an artificial conducting system for tutoring purposes that uses real-time audio analysis of music played by musicians and uses this analysis to animate a virtual human that acts as a conductor. The analysis detects the tempo and the dynamics of the music, compares the

  15. Current Density Distribution on the Perimeter of Waveguide Exciter Cylindrical Vibrator Conductor

    OpenAIRE

    Zakharia, Yosyp

    2010-01-01

    On ground of electrodynamic analysis the surface current distribution nonuniformity on the perimeter of waveguide-exciter cylindrical conductor is found. Considerable influence of current distribution nonuniformity on exciter input reactance is established. It is also showed, that the current distribution on the vibrator perimeter, for conductor radius no greater then 0,07 of waveguide cross section breadth, approximately uniform is.

  16. Twenty years of cable-in-conduit conductors: 1975-1995

    International Nuclear Information System (INIS)

    Dresner, L.

    1995-01-01

    This paper reviews our progress during the last two decades in understanding cable-in-conduit conductors. The emphasis is on the physical principles governing the behavior of cable-in-conduit conductors, and no detailed mathematics is presented. The paper is constructed as a historical narrative

  17. Transport current dependence of the hysteresis loss in silver sheathed BSCOO-2212 conductors

    NARCIS (Netherlands)

    Hemmes, Herman K.; Woudstra, Martin J.; ten Kate, Herman H.J.; Tenbrink, Johannes

    1994-01-01

    A technique is described to study the critical current density and penetration fieldassociated with the transport current in a silver sheathed BSCCO conductor. A transport current flowing in a conductor in a varying magnetic field will only influence magnetisation currents that are in competition

  18. Measuring ac-loss in high temperature superconducting cable-conductors using four probe methods

    DEFF Research Database (Denmark)

    Kühle (fratrådt), Anders Van Der Aa; Træholt, Chresten; Olsen, Søren Krüger

    1999-01-01

    Measuring the ac-loss of superconducting cable conductors have many aspects in common with measuring the ac-loss of single superconducting tapes. In a cable conductor all tapes are connected to each other and to the test circuit through normal metal joints in each end. This makes such measurement...

  19. The CEA JOSEFA test facility for sub-size conductors and joints

    International Nuclear Information System (INIS)

    Decool, P.; Libeyre, P.; Van Houtte, D.; Ciazynski, D.; Zani, L.; Serries, J.P.; Cloez, H.; Bej, S.

    2003-01-01

    The JOSEFA (Joint Sub-size Experiment FAcility) experimental test facility, installed at CEA/Cadarache is devoted to perform tests at cryogenic temperature on sub-size superconducting conductor and joint samples under parallel or transverse magnetic field. This facility was built in 1993 to investigate the performances of joints of cable-in-conduit conductors at sub-size level and further upgraded in the framework of European tasks. The samples of hairpin type using sub-size ITER conductors are cooled by a circulation of supercritical helium in a temperature range from 5 to 15 K and tested at a maximum current up to 10 kA. Two different helium bath cooled magnets allow to apply DC or AC transverse magnetic field up to 3.5 T or longitudinal magnetic field up to 7.5 T. A sliding system with a 240 mm stroke on the sample cryostat allows to test separately in the same sample either the conductor or the joint performances. The paper reports on how, through the conductor and joint development tasks, the facility performances were successfully increased and tested. The ITER TFMC joints using Nb3Sn conductors were first developed on this facility. The last developments, performed on ITER PF NbTi conductors and joints proved this facility to be a versatile and useful tool for superconducting magnet developments and showed the interest of possible upgrading to finalize conductor design. (author)

  20. Status of European manufacture of Toroidal Field conductor and strand for JT-60SA project

    Energy Technology Data Exchange (ETDEWEB)

    Zani, Louis, E-mail: louis.zani@jt60sa.org [Fusion for Energy, D-85748 Garching (Germany); CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Barabaschi, Pietro; Di Pietro, Enrico [Fusion for Energy, D-85748 Garching (Germany)

    2013-10-15

    In the framework of the JT-60SA project, part of the Broader Approach (BA) agreement, EURATOM provides to Japan, the Toroidal Field (TF) magnet system, consisting of 18 superconducting coils. The procurement of the conductor for the TF coils is managed by Fusion for Energy, acting as EU representative in the BA agreement. The TF conductor procurement is split into two contracts, one dedicated to the production of Niobium Titanium (NbTi) and Cu strand and the other to TF conductor production through strand cabling and cable jacketing operations. The TF conductor is a rectangular-shaped cable-in-conduit conductor formed by 486 (0.81 mm diameter) strands (2/3 NbTi–1/3 Cu) wrapped in a stainless steel foil and embedded into a stainless steel jacket. The 18 TF coils require (including spares) 115 ‘Unit Lengths’ (UL) of such conductor, each 240 m long for a total of about 28 km. Correspondingly about 10,000 km for NbTi and 5000 km for Cu strand are produced. The Japanese company Furukawa Electric Co. (FEC) is in charge of TF strand manufacture while the Italian company Italian Consortium for Applied Superconductivity (ICAS) is in charge of cabling and jacketing of TF conductor ULs. In the paper, we provide information on the production stages presently achieved in TF strand and conductor contracts.

  1. Fabrication process of a superconducting multifilament conductor of a cable and resulting electric conductor. Procede de fabrication d'un conducteur a brins multifilamentaires supraconducteurs, et conducteur en resultant

    Energy Technology Data Exchange (ETDEWEB)

    Fevrier, A; Verhaege, T; Bonnet, P

    1990-10-05

    Elementary conductors constituted of a plurality of superconducting filaments in a metallic matrix are prepared and then twisted. Elementary conductors with a diameter between 0.05 and 0.25 mm without electric insulation are twisted after heating with a pitch of four time the diameter, finally the conductor is insulated.

  2. CCAN and TCAN - 1 1/2-D compressible-flow and time-dependent codes for conductor analysis

    International Nuclear Information System (INIS)

    Gierszewski, P.J.; Wan, A.S.; Yang, T.F.

    1983-01-01

    This report documents the computer programs CCAN (steady-state Compressible flow Conductor ANalysis) and TCAN (Time-dependent incompressible-flow Conductor ANalysis). These codes calculate temperature, pressure, power and other engineering quantities along the length of an actively-cooled electrical conductor. Present versions contain detailed property information for copper and aluminum conductors; and gaseous helium, liquid nitrogen and water coolants. CCAN and TCAN are available on the NMFECC CDC 7600

  3. Molecular dynamics study of dislocation cores in copper: structure and diffusion at high temperatures

    International Nuclear Information System (INIS)

    Huang, Jin

    1989-01-01

    The variation of the core structure of an easy glide dislocation with temperature and its influence on the stacking fault energy (γ) have been investigated for the first time by molecular-dynamics simulation in copper. The calculations have been performed at various temperatures, using an ab-initio pseudo-potential. Our results show that the core of the Shockley partials, into which the perfect edge dislocation dissociates, becomes increasingly extended as temperature increases. However their separation remains constant. The calculated energy values of the infinite extension stacking fault and the ribbon fault between the partials are quite different, but the evolution of the core structure does not affect the temperature dependence of the latter. We have found that a high disorder appears in the core region when temperature increases due to important anharmonicity effects of the atomic vibrations. The core structure remains solid-like for T m (T m : melting point of bulk) in spite of the high disorder. Above T m , the liquid nucleus germinates in the core region, and then propagates into the bulk. In addition we studied the mobility of vacancies and interstitials trapped on the partials. Although fast diffusion is thought to occur exclusively in a pipe surrounding the dislocation core, in the present study a quasi two-dimensional diffusion is observed for both defects not only in the cores but also in the stacking fault ribbon. On the opposite of current assumptions, the activation energy for diffusion is found to be identical for both defects, which may therefore comparably contribute to mass transport along the dislocations. (author) [fr

  4. Electromagnetic response of a conductor with complex conductivity

    Science.gov (United States)

    Leylekian, L.; Ocio, M.; Hammann, J.

    1993-02-01

    The aim of this paper is to describe the electromagnetic response of a conductor with complex conductivity. We will show how the geometry of the measuring apparatus can modify the amplitude of this response. We will particularly emphasize the role that plays a complex conductivity, as we can find in granular superconductors, on the mesured magnetic susceptibility of the sample. Cet article a pour but de décrire la réponse électromagnétique d'un conducteur muni d'une conductivité complexe. Nous montrerons comment la géométrie du dispositif de mesure peut modifier l'amplitude de cette réponse. Nous insisterons particulièrement sur le rôle que joue une conductivité complexe, comme nous pouvons en trouver dans les supraconducteurs granulaires, sur la susceptibilité magnétique mesurée de l'échantillon.

  5. Control of Flux Pinning in MOD YBCO Coated Conductor

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, W. [American Superconductor Corporation, Westborough, MA; Huang, Y. [American Superconductor Corporation, Westborough, MA; Li, X. [American Superconductor Corporation, Westborough, MA; Kodenkandath, Thomas [American Superconductor Corporation, Westborough, MA; Rupich, Marty [American Superconductor Corporation, Westborough, MA; Schoop, U. [American Superconductor Corporation, Westborough, MA; Verebelyi, D. T. [American Superconductor Corporation, Westborough, MA; Thieme, C. L. H. [American Superconductor Corporation, Westborough, MA; Siegal, E. E. [American Superconductor Corporation, Westborough, MA; Holesinger, T. G. [Los Alamos National Laboratory (LANL); Maiorov, B. [Los Alamos National Laboratory (LANL); Miller, D. J. [Argonne National Laboratory (ANL); Maroni, V. A. [Argonne National Laboratory (ANL); Goyal, Amit [ORNL; Specht, Eliot D [ORNL; Paranthaman, Mariappan Parans [ORNL

    2007-01-01

    Two different types of defect structures have been identified to be responsible for the enhanced pinning in metal organic deposited YBCO films. Rare earth additions result in the formation of nanodots in the YBCO matrix, which form uncorrelated pinning centers, increasing pinning in all magnetic field orientations. 124-type intergrowths, which form as laminar structures parallel to the ab-plane, are responsible for the large current enhancement when the magnetic field is oriented in the ab-plane. TEM studies showed that the intergrowths emanate from cuprous containing secondary phase particles, whose density is partially controlled by the rare earth doping level. Critical process parameters have been identified to control this phase formation, and therefore, control the f 24 intergrowth formation. This work has shown that through process control and proper conductor design, either by adjusting the composition or by multiple coatings of different functional layers, the desired angular dependence can be achieved.

  6. Control of flux pinning in MOD YBCO coated conductor.

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, W.; Huang, Y.; Li, X.; Kodenkandath, T.; Rupich, M. W.; Schoop, U.; Verebelyi, D. T.; Thieme, C. L. H.; Siegal, E.; Holesinger, T. G.; Maiorov, B.; Civale, L.; Miller, D. J.; Maroni, V. A.; Li, J.; Martin, P. M.; Specht, E. D.; Goyal, A.; Paranthaman, M. P.; American Superconductor Corp.; LANL; ORNL

    2007-06-01

    NTwo different types of defect structures have been identified to be responsible for the enhanced pinning in metal organic deposited YBCO films. Rare earth additions result in the formation of nanodots in the YBCO matrix, which form uncorrelated pinning centers, increasing pinning in all magnetic field orientations. 124-type intergrowths, which form as laminar structures parallel to the ab-plane, are responsible for the large current enhancement when the magnetic field is oriented in the ab-plane. TEM studies showed that the intergrowths emanate from cuprous containing secondary phase particles, whose density is partially controlled by the rare earth doping level. Critical process parameters have been identified to control this phase formation, and therefore, control the f 24 intergrowth formation. This work has shown that through process control and proper conductor design, either by adjusting the composition or by multiple coatings of different functional layers, the desired angular dependence can be achieved.

  7. Why is AgBr not a superionic conductor

    International Nuclear Information System (INIS)

    Andreoni, W.; Tosi, M.P.

    1982-03-01

    The behaviour of AgCl and AgBr is contrasted with that of fluorite-type crystals, which also are Frenkel conductors at low temperatures but undergo a diffuse transition to a superionic phase before melting. Concentrating on AgBr for which the relevant defect parameters are better known, a Debye-Hueckel model for the interactions between defects, modified for saturation of screening at high defect concentrations, is used to show that both Frenkel and Schottky disorder are present and rapidly increasing with temperature in the hot solid, with the Schottky component rapidly overtaking the Frenkel component. It is suggested that this defect behaviour frustrates a superionic transition and leads to melting accompanied by an anomalous ionic conductivity in the premelting region. The model is tested by a comparison with data on the Frenkel defect concentration in superionic PbF 2 . (author)

  8. Computation of transient 3-D eddy current in nonmagnetic conductor

    International Nuclear Information System (INIS)

    Yeh, H.T.

    1978-01-01

    A numerical procedure was developed to solve transient three-dimensional (3-D) eddy current problems for nonmagnetic conductor. Integral equation formulation in terms of vector potential is used to simplify the matching of boundary conditions. The resulting equations and their numerical approximation were shown to be singular and to require special handling. Several types of symmetries were introduced. They not only reduce the number of algebraic equations to be solved, but also modify the nature of the equations and render them nonsingular. Temporal behavior was obtained with the Runge-Kutta method. The program is tested in several examples of eddy currents for its spatial and temporal profiles, shielding, boundary surface effects, and application of various symmetry options

  9. Admittance of multiterminal quantum Hall conductors at kilohertz frequencies

    International Nuclear Information System (INIS)

    Hernández, C.; Consejo, C.; Chaubet, C.; Degiovanni, P.

    2014-01-01

    We present an experimental study of the low frequency admittance of quantum Hall conductors in the [100 Hz, 1 MHz] frequency range. We show that the frequency dependence of the admittance of the sample strongly depends on the topology of the contacts connections. Our experimental results are well explained within the Christen and Büttiker approach for finite frequency transport in quantum Hall edge channels taking into account the influence of the coaxial cables capacitance. In the Hall bar geometry, we demonstrate that there exists a configuration in which the cable capacitance does not influence the admittance measurement of the sample. In this case, we measure the electrochemical capacitance of the sample and observe its dependence on the filling factor

  10. Admittance of multiterminal quantum Hall conductors at kilohertz frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Hernández, C. [Departamento de Física, Universidad Militar Nueva Granada, Carrera 11 101-80 Bogotá D.C. (Colombia); Consejo, C.; Chaubet, C., E-mail: christophe.chaubet@univ-montp2.fr [Université Montpellier 2, Laboratoire Charles Coulomb UMR5221, F-34095 Montpellier, France and CNRS, Laboratoire Charles Coulomb UMR5221, F-34095 Montpellier (France); Degiovanni, P. [Université de Lyon, Fédération de Physique Andrée Marie Ampère, CNRS, Laboratoire de Physique de l' Ecole Normale Supérieure de Lyon, 46 allée d' Italie, 69364 Lyon Cedex 07 (France)

    2014-03-28

    We present an experimental study of the low frequency admittance of quantum Hall conductors in the [100 Hz, 1 MHz] frequency range. We show that the frequency dependence of the admittance of the sample strongly depends on the topology of the contacts connections. Our experimental results are well explained within the Christen and Büttiker approach for finite frequency transport in quantum Hall edge channels taking into account the influence of the coaxial cables capacitance. In the Hall bar geometry, we demonstrate that there exists a configuration in which the cable capacitance does not influence the admittance measurement of the sample. In this case, we measure the electrochemical capacitance of the sample and observe its dependence on the filling factor.

  11. YBCO coated conductors by reactive thermal co-evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Schmatz, U.; Hoffmann, Ch.; Bauer, M.; Metzger, R.; Berberich, P.; Kinder, H. [Technische Univ. Muenchen, Garching (Germany). Physik-Department

    2001-12-01

    Coated tape conductors of YBCO require a deposition process allowing to obtain a high volume growth rate in order to produce long lengths of tape in a reasonable amount of time. We present our tape coating system where 15 parallel loops of travelling tape of 1 cm width can be coated simultaneously by reactive thermal co-evaporation. For high critical current densities, in-plane alignment of the YBCO film is necessary. Inclined substrate deposition (ISD) is a technique that allows to deposit in-plane oriented buffer layers suitable for YBCO growth at high deposition rates. We present results obtained for YBCO films grown on MgO-ISD buffer layers deposited by e-gun evaporation onto metallic tape substrates. (orig.)

  12. Ground-based transmission line conductor motion sensor

    International Nuclear Information System (INIS)

    Jacobs, M.L.; Milano, U.

    1988-01-01

    A ground-based-conductor motion-sensing apparatus is provided for remotely sensing movement of electric-power transmission lines, particularly as would occur during the wind-induced condition known as galloping. The apparatus is comprised of a motion sensor and signal-generating means which are placed underneath a transmission line and will sense changes in the electric field around the line due to excessive line motion. The detector then signals a remote station when a conditioning of galloping is sensed. The apparatus of the present invention is advantageous over the line-mounted sensors of the prior art in that it is easier and less hazardous to install. The system can also be modified so that a signal will only be given when particular conditions, such as specific temperature range, large-amplitude line motion, or excessive duration of the line motion, are occurring

  13. PAC study of ionic motion in silver compound superionic conductors

    International Nuclear Information System (INIS)

    Mekata, M.; Seguchi, Y.

    1983-01-01

    Ionic motion in superionic conductors, Ag 2 S, Ag 2 Se and Ag 3 SI was investigated by γ-γ PAC on 111 Cd. Diffusion constant measurements showed that probe ions migrate almost as fast as Ag + ions above 500 K in Ag 2 S and Ag 2 Se and above 700 K in Ag 3 SI. Multivalent impurities were found to be unstable in AgI and Ag 2 Te. The correlation time of ionic motion was deduced from the observed relaxation rate together with the diffusion constants. The correlation time and its activation energy increase in order of Ag 2 S, Ag 2 Se and Ag 3 SI. The flight distance of Ag + ions remains almost constant in the measured temperature range. (Auth.)

  14. Cable-in-conduit conductor optimization for fusion magnet applications

    International Nuclear Information System (INIS)

    Miller, J.R.; Kerns, J.A.

    1987-01-01

    Careful design of the toroidal-field (TF) and poloidal-field (PF) coils in a tokamak machine using cable-in-conduit conductors (CICC) can result in quite high overall winding-pack current densities - even with the high nuclear heat loads that may be imposed in operating a fusion reactor - and thereby help reduce the overall machine size. In our design process, we systematically examined the operational environment of a magnet, e.g., mechanical stresses, current, field, heat load, coolant temperature, and cooldown stresses, to determine the optimum amounts of copper, superconductor, helium, and sheath material for the CICC. This process is being used to design the superconducting magnet systems that comprise the Tokamak Ignition/Burn Experimental Reactor (TIBER II). 13 refs., 2 figs

  15. On Faraday's law in the presence of extended conductors

    Science.gov (United States)

    Bilbao, Luis

    2018-06-01

    The use of Faraday's Law of induction for calculating the induced currents in an extended conducting body is discussed. In a general case with arbitrary geometry, the solution to the problem of a moving metal object in the presence of a magnetic field is difficult and implies solving Maxwell's equations in a time-dependent situation. In many cases, including cases with good conductors (but not superconductors) Ampère's Law can be neglected and a simpler solution based solely in Faraday's law can be obtained. The integral form of Faraday's Law along any loop in the conducting body is equivalent to a Kirkhhoff's voltage law of a circuit. Therefore, a numerical solution can be obtained by solving a linear system of equations corresponding to a discrete number of loops in the body.

  16. Manufacture of the Poloidal Field Conductor Insert Coil (PFCI)

    International Nuclear Information System (INIS)

    Baker, W.; Rajainmaeki, H.; Salpietro, E.; Keefe, C.

    2006-01-01

    Within the framework of the R(and)D programme for ITER (International Thermonuclear Experimental Reactor) the European team EFDA (European Fusion Development Agreement) have been charged with the design and manufacture of the Poloidal Field Conductor Insert Coil (PFCI). The purpose of the PFCI is to test and demonstrate the performance of long length full scale NbTi conductors in ITER relevant conditions. The PFCI will be tested in the Central Solenoid Model Coil test facility at the JAEA Naka Japan. This paper details the complete manufacturing details of the PFCI including development, forming machining, pre-assembly, impregnation, final assembly and testing. The PFCI is a single layer wound solenoid of 9 turns with a transition joggle in the centre section of the winding and an intermediate joint connection between the upper termination and the main coil winding. To give the required overall dimensions to fit in the testing facility, pre-formed and machined glass resin composite filler pieces are assembled with the winding and finally Vacuum Pressure Impregnated to create a single assembly unit. The PFCI is enclosed for assembly in a support structure which consist of an upper and lower flange that each are made up by 4 machined stainless steel castings which are electrically insulated by epoxy glass sheet material and 12 tie rods which preload the complete assembly in the vertical direction while the upper flange is equipped with 4 radial restraining jacks and the lower flange is equipped with 4 sets of studs and shear keys to withstand the net vertical and lateral electromagnetic forces. The PFCI is equipped with inductive heaters, voltage taps, temperature transducers, strain gauges and other instrumentation as diagnostics to monitor the performance. The current status of the manufacture is that the coil is in the process of final impregnation and should be completed and delivered before the summer of this year. (author)

  17. Manufacture of the poloidal field conductor insert coil (PFCI)

    Energy Technology Data Exchange (ETDEWEB)

    Baker, W. [EFDA CSU Garching, Boltzmannstrasse 2, 85748 Garching bei Muenchen (Germany); Keefe, C. [Tesla Engineering, Storrington, Sussex (United Kingdom); Rajainmaeki, H. [EFDA CSU Garching, Boltzmannstrasse 2, 85748 Garching bei Muenchen (Germany)], E-mail: hannu.rajainmaki@tech.efda.org; Salpietro, E. [EFDA CSU Garching, Boltzmannstrasse 2, 85748 Garching bei Muenchen (Germany)

    2007-10-15

    Within the framework of the R and D programme for international thermonuclear experimental reactor (ITER) the European team European Fusion Development Agreement (EFDA) has been charged with the design and manufacture of the poloidal field conductor insert coil (PFCI). The purpose of the PFCI is to test and demonstrate the performance of long-length full-scale NbTi conductors in ITER-relevant conditions. The PFCI will be tested in the central solenoid model coil test facility at the JAEA, Naka, Japan. This paper details the complete manufacturing of the PFCI including development, forming machining, pre-assembly, impregnation, final assembly and testing. The PFCI is a single-layered wound solenoid of nine turns with a transition joggle in the centre section of the winding and an intermediate joint connection between the upper termination and the main coil winding. To give the required overall dimensions to fit in the testing facility, preformed and machined glass resin composite filler pieces are assembled with the winding and is finally vacuum pressure impregnated (VPI) to create a single assembly unit. The PFCI is enclosed for assembly in a support structure, which consists of an upper and lower flange, each made up of four electrically insulated machined stainless steel castings, and 12 tie rods preloading the complete assembly in the vertical direction. The upper flange is equipped with four radial restraining jacks and the lower flange is equipped with four sets of studs and shear keys to withstand the net vertical and lateral electromagnetic forces. The PFCI is equipped with inductive heaters, voltage taps, temperature transducers, strain gauges and other instrumentation as diagnostics to monitor the performance. The current status of the manufacture is that the coil has passed the final acceptance tests and it is in the support structure assembly stage.

  18. Far-field potentials in cylindrical and rectangular volume conductors.

    Science.gov (United States)

    Dumitru, D; King, J C; Rogers, W E

    1993-07-01

    The occurrence of a transient dipole is one method of producing a far-field potential. This investigation qualitatively defines the characteristics of the near-field and far-field electrical potentials produced by a transient dipole in both cylindrical and rectangular volume conductors. Most body segments of electrophysiologic interest such as arms, legs, thorax, and neck are roughly cylindrical in shape. A centrally located dipole generator produces a nonzero equipotential region which is found to occur along the cylindrical wall at a distance from the dipole of approximately 1.4 times the cylinder's radius and 1.9 times the cylinder's radius for the center of the cylinder. This distance to the equi-potential zone along the surface wall expands but remains less than 3.0 times the cylindrical radius when the dipole is eccentrically placed. The magnitude of the equipotential region resulting from an asymmetrically placed dipole remains identical to that when the dipole is centrally located. This behavior is found to be very similar in rectangular shallow conducting volumes that model a longitudinal slice of the cylinder, thus allowing a simple experimental model of the cylinder to be utilized. Amplitudes of the equipotential region are inversely proportional to the cylindrical or rectangular volume's cross-sectional area at the location of dipolar imbalance. This study predicts that referential electrode montages, when placed at 3.0 times the radius or greater from a dipolar axially aligned far-field generator in cylindrical homogeneous volume conductors, will record only equipotential far-field effects.

  19. Detection of smaller Jc region and damage in YBCO coated conductors by using permanent magnet method

    International Nuclear Information System (INIS)

    Hattori, K.; Saito, A.; Takano, Y.; Suzuki, T.; Yamada, H.; Takayama, T.; Kamitani, A.; Ohshima, S.

    2011-01-01

    We developed a non-destructive method for measuring the critical current density (J c ) in YBCO-coated conductors by using a permanent magnet (Sm 2 Co 17 ). J c could be determined from the repulsive force (F r ) generated between a permanent magnet and a coated conductor where shielding current flows. We also examined the influence of damage to the film on the J c distribution. The measured F r when the permanent magnet approached the cut part was smaller than that of the undamaged area. We developed a non-destructive method for measuring the critical current density (J c ) in YBCO-coated conductors by using a permanent magnet (Sm 2 Co 17 ). J c could be determined from the repulsive force (F r ) generated between a permanent magnet and a coated conductor where shielding current flows. We tried to detect a smaller J c region in the coated conductor by using the system. The J c distribution could be determined without influence from the thick copper film on YBCO thin film. We also examined the influence of damage to the film on the J c distribution. The surface of the coated conductors was cut by using a knife. The measured F r when the permanent magnet approached the cut part was smaller than that of the undamaged area. This J c measurement technique will be useful for detecting smaller J c regions and defects in coated conductors.

  20. Development of 1 m HTS conductor using YBCO on textured metal substrate

    International Nuclear Information System (INIS)

    Yagi, M.; Sakamoto, H.; Mukoyama, S.; Yamamoto, K.; Amemiya, N.; Nagaya, S.; Kashima, N.; Shiohara, Y.

    2009-01-01

    We fabricated 1 m high temperature superconducting conductor (HTS conductor) using YBa 2 Cu 3 O 7-x coated conductors (YBCO tapes) on textured metal substrates, which are expected to be lower in cost than YBCO tapes using ion-beam assisted deposition. Those substrate and intermediate layers were manufactured by Furukawa Electric, and YBCO and a protective layer were applied to the intermediate layer by Chubu Electric Power. Before fabricating the conductor, a 0.1 mm thick copper tape was soldered to the YBCO tape, and 10 mm wide YBCO tape was divided into three strips by a YAG laser. To have sufficient current capacity for 1 kA, a two-layer conductor was fabricated, and its critical current (I c ) was 1976 A, but the magnetic properties of the textured metal substrates affected the increase in AC loss. In a low current region, the AC loss in this conductor was much higher than the Norris strip model, but approached the Norris strip model in the high current region because the magnetization was almost saturated. Low AC loss of 0.144 W/m at 1 kA rms was achieved even though the conductor had a small outer diameter of 20 mm and was composed of YBCO tapes with magnetic substrates.

  1. Calorimetric method for current sharing temperature measurements in ITER conductor samples in SULTAN

    International Nuclear Information System (INIS)

    Bagnasco, M.

    2009-01-01

    Several Toroidal Field Conductor short samples with slight layout variations have been assembled and tested in the SULTAN facility at CRPP. The measurement campaigns started in 2007 and are still ongoing. The performance of every conductor is expressed in terms of current sharing temperature (T cs ), i.e. the temperature at which a defined electric field, 10 μV/m, is detected in the cable due to the incipient superconducting-to-normal state transition. The T cs at specific operating conditions is the key design parameter for the ITER conductors and is the main object of the qualification tests. Typically, the average electric field is measured with voltage tap pairs attached on the jacket along the conductor. The inability however to explain observed premature voltage developments opened the discussion about possible alternative measuring methods. The He flow calorimetric method is based on the measurement of the resistive power generation in the conductor. It relies on the detection of very small temperature increases along the conductor in steady state operation. The accuracy and the reliability of the calorimetric method in SULTAN are critically discussed, with particular emphasis on the instrumentation requirements and test procedures. The application of the calorimetric method to the recent SULTAN test campaigns is described with its merits and limits. For future tests of ITER conductors in SULTAN, the calorimetric method for T cs test is proposed as a routine procedure.

  2. A Novel Method for Detection and Classification of Covered Conductor Faults

    Directory of Open Access Journals (Sweden)

    Stanislav Misak

    2016-01-01

    Full Text Available Medium-Voltage (MV overhead lines with Covered Conductors (CCs are increasingly being used around the world primarily in forested or dissected terrain areas or in urban areas where it is not possible to utilize MV cable lines. The CC is specific in high operational reliability provided by the conductor core insulation compared to Aluminium-Conductor Steel-Reinforced (ACSR overhead lines. The only disadvantage of the CC is rather the problematic detection of faults compared to the ACSR. In this work, we consider the following faults: the contact of a tree branch with a CC and the fall of a conductor on the ground. The standard protection relays are unable to detect the faults and so the faults pose a risk for individuals in the vicinity of the conductor as well as it compromises the overall safety and reliability of the MV distribution system. In this article, we continue with our previous work aimed at the method enabling detection of the faults and we introduce a method enabling a classification of the fault type. Such a classification is especially important for an operator of an MV distribution system to plan the optimal maintenance or repair the faulty conductors since the fall of a tree branch can be solved later whereas the breakdown of a conductor means an immediate action of the operator.

  3. Electrohydrodynamic direct—writing of conductor—insulator-conductor multi-layer interconnection

    International Nuclear Information System (INIS)

    Zheng Gao-Feng; Pei Yan-Bo; Wang Xiang; Zheng Jian-Yi; Sun Dao-Heng

    2014-01-01

    A multi-layer interconnection structure is a basic component of electronic devices, and printing of the multi-layer interconnection structure is the key process in printed electronics. In this work, electrohydrodynamic direct-writing (EDW) is utilized to print the conductor—insulator—conductor multi-layer interconnection structure. Silver ink is chosen to print the conductor pattern, and a polyvinylpyrrolidone (PVP) solution is utilized to fabricate the insulator layer between the bottom and top conductor patterns. The influences of EDW process parameters on the line width of the printed conductor and insulator patterns are studied systematically. The obtained results show that the line width of the printed structure increases with the increase of the flow rate, but decreases with the increase of applied voltage and PVP content in the solution. The average resistivity values of the bottom and top silver conductor tracks are determined to be 1.34 × 10 −7 Ω·m and 1.39 × 10 −7 Ω·m, respectively. The printed PVP layer between the two conductor tracks is well insulated, which can meet the insulation requirement of the electronic devices. This study offers an alternative, fast, and cost-effective method of fabricating conductor—insulator—conductor multi-layer interconnections in the electronic industry

  4. Development of an YBCO coil with SSTC conductors for high field application

    Science.gov (United States)

    Shi, Y.; Liu, H. J.; Liu, F.; Tan, Y. F.; Jin, H.; Yu, M.; Lei, L.; Guo, L.; Hong, Z. Y.

    2018-07-01

    With the continuous reduction of the production costs and improvement of the transport performance, YBCO coated conductor is the most promising candidate for the high field magnet application due to its high irreversibility field and strong mechanical properties. Presently a stable production capacity of the YBCO conductors has been achieved by Shanghai Superconducting Technology Co., Ltd (SSTC) in China. Therefore, the demand in high field application with YBCO conductors is growing in China. This paper describes the design, fabrication and preliminary experiment of a solenoid coil with YBCO conductors supplied by SSTC to validate the possibility of high field application. Four same double pancakes were manufactured and assembled for the YBCO coil where the outer diameter and height was 54.3 and 48 mm respectively to match the dimensional limitation of the 14 T background magnets. The critical current (Ic) of YBCO conductors was obtained by measuring as a function of the applied field perpendicular to the YBCO conductor surface which provides the necessary input parameters for preliminary performance evaluation of the coil. Finally the preliminary test and discussion at 77 and 4.2 K were carried out. The consistency of four double pancakes Ic was achieved. The measured results indicate that the fabrication technology of HTS coil is reliable which gives the conference for the in-field test in high field application. This YBCO coil is the first demonstration of the SSTC YBCO coated conductors.

  5. Corona Onset Characteristics of Bundle Conductors in UHV AC Power Lines at 2200 m Altitude

    Directory of Open Access Journals (Sweden)

    Shilong Huang

    2018-04-01

    Full Text Available The corona onset characteristic of bundle conductors is an important limiting factor for the design of UHV AC power lines in high-altitude areas. An experimental study on the corona characteristics of 8 × LGJ630, 6 × LGJ720, 8 × LGJ720 and 10 × LGJ720 bundle conductors commonly used in UHV power lines under dry and wet conductor conditions, as well as artificial moderate and heavy rain conditions, was conducted in Ping’an County, Xining City (elevation 2200 m. By using the tangent line method, the corona onset voltages and onset electric field of four types of conductors at high altitudes are obtained for the first time. In addition, the calculation model of corona onset voltage considering the outer strands’ effect on the electric field and the geometric factor in the corona cage in high altitude areas is established. The comparison of the calculation results and experimental results under dry conditions verifies the model’s correctness. Based on the results, an optimal selection scheme for high altitudes is proposed. The roughness coefficient was also calculated and analysed: the roughness coefficient of bundled conductors was between 0.59 and 0.77, and the roughness coefficient of the wet conductor was between the dry and rainy conditions. Both the experimental data and the calculation model can provide a reference for conductor selection for UHV AC power lines for use in high-altitude areas.

  6. Many-polaron theory for superconductivity and charge-density waves in a strongly coupled electron-phonon system with quasi-two-dimensionality: An interpolation between the adiabatic limit and the inverse-adiabatic limit

    International Nuclear Information System (INIS)

    Nasu, K.

    1987-01-01

    The phase diagram of a two-dimensional N-site N-electron system (N>>1) with site-diagonal electron-phonon (e-ph) coupling is studied in the context of polaron theory, so as to clarify the competition between the superconducting (SC) state and the charge-density wave (CDW) state. The Fermi surface of noninteracting electrons is assumed to be a complete circle with no nesting-type instability in the case of weak e-ph coupling, so as to focus on such a strong coupling that even the standard ''strong-coupling theory'' for superconductivity breaks down. Phonon clouds moving with electrons as well as a frozen phonon are taken into account by a variational method, combined with a mean-field theory. It covers the whole region of three basic parameters characterizing the system: the intersite transfer energy of electron T, the e-ph coupling energy S, and the phonon energy ω. The resultant phase diagram is given in a triangular coordinate space spanned by T, S, and ω. In the adiabatic region ω >(T,S) near the ω vertex of the triangle, on the other hand, each electron becomes a small polaron, and the SC state is always more stable than the CDW state, because the retardation effect is absent

  7. Assessment of the noise annoyance among subway train conductors in Tehran, Iran.

    Science.gov (United States)

    Hamidi, Mansoureh; Kavousi, Amir; Zaheri, Somayeh; Hamadani, Abolfazl; Mirkazemi, Roksana

    2014-01-01

    Subway transportation system is a new phenomenon in Iran. Noise annoyance interferes with the individual's task performance, and the required alertness in the driving of subway trains. This is the first study conducted to measure the level of noise and noise annoyance among conductors of subway organization in Tehran, Iran. This cross sectional study was conducted among 167 randomly selected train conductors. Information related to noise annoyance was collected by using a self-administered questionnaire. The dosimetry and sound metering was done for the conductors and inside the cabins. There were 41 sound metering measuring samples inside the conductors' cabin, and there were 12 samples of conductors' noise exposure. The results of sound level meter showed that the mean Leq was 73.0 dBA ± 8.7 dBA and the dosimetry mean measured Leq was 82.1 dBA ± 6.8 dBA. 80% of conductors were very annoyed/annoyed by noise in their work place. 53.9% of conductors reported that noise affected their work performance and 63.5% reported that noise causes that they lose their concentration. The noise related to movement of train wheels on rail was reported as the worst by 83.2% followed by the noise of brakes (74.3%) and the ventilation noise (71.9%). 56.9% of conductors reported that they are suffering from sleeplessness, 40.1% from tinnitus and 80.2% feeling fatigue and sleepy. The study results showed the high level of noise and noise annoyance among train conductors and the poor health outcome of their exposure to this level of noise.

  8. Modeling the electrical resistance of gold film conductors on uniaxially stretched elastomeric substrates

    Science.gov (United States)

    Cao, Wenzhe; Görrn, Patrick; Wagner, Sigurd

    2011-05-01

    The electrical resistance of gold film conductors on polydimethyl siloxane substrates at stages of uniaxial stretching is measured and modeled. The surface area of a gold conductor is assumed constant during stretching so that the exposed substrate takes up all strain. Sheet resistances are calculated from frames of scanning electron micrographs by numerically solving for the electrical potentials of all pixels in a frame. These sheet resistances agree sufficiently well with values measured on the same conductors to give credence to the model of a stretchable network of gold links defined by microcracks.

  9. n value and Jc distribution dependence of AC transport current losses in HTS conductors

    International Nuclear Information System (INIS)

    Ogawa, Jun; Sawai, Yusuke; Nakayama, Haruki; Tsukamoto, Osami; Miyagi, Daisuke

    2004-01-01

    Compared with LTS materials, HTS materials have some peculiarities affecting AC loss characteristics of the conductors. We measured the AC transport current losses in YBCO thin film coated conductors and a Bi2223/Ag sheathed tape. Comparing the measured data with analytical calculations, the dependence of the AC transport current losses on the n value and critical current density distributions are studied. It is shown that, considering the n values and J c distributions, the peculiarities in the HTS materials can be taken into consideration and the transport current losses in HTS conductors can be calculated by the same analytical method used for LTS

  10. Stress-induced heating in commercial conductors and its possible influence on magnet performance

    International Nuclear Information System (INIS)

    Easton, D.S.; Kroeger, D.M.; Moazed, A.

    1976-01-01

    Calorimetric measurements show that significant amounts of heat are generated when a multifilamentary composite conductor is stressed in tension to levels expected to occur in large, high-field magnet systems. When the stress on the conductor is repetitively cycled between zero and some maximum value, the amount of heat produced per cycle is constant after the first few cycles. Comparison is made between calorimetric determinations of heat injections and the work done on the specimen as indicated by stress-strain curves. Stress-strain curves for a number of commercial conductors indicate that the most important determinant of the magnitude of this effect is the choice of matrix material

  11. Phonon-electron coupling and tunneling effect on charge transport in organic semi-conductor crystals of Cn-BTBT

    Science.gov (United States)

    Zhou, Yecheng; Deng, Wei-Qiao; Zhang, Hao-Li

    2016-09-01

    Cn-[1]benzothieno[3,2-b][1]-benzothiophene (BTBT) crystals show very high hole mobilities in experiments. These high mobilities are beyond existing theory prediction. Here, we employed different quantum chemistry methods to investigate charge transfer in Cn-BTBT crystals and tried to find out the reasons for the underestimation in the theory. It was found that the hopping rate estimated by the Fermi Golden Rule is higher than that of the Marcus theory due to the high temperature approximation and failure at the classic limit. More importantly, molecular dynamics simulations revealed that the phonon induced fluctuation of electronic transfer integral is much larger than the average of the electronic transfer integral itself. Mobilities become higher if simulations implement the phonon-electron coupling. This conclusion indicates that the phonon-electron coupling promotes charge transfer in organic semi-conductors at room temperature.

  12. Remarkable weakness against cleavage stress for YBCO-coated conductors and its effect on the YBCO coil performance

    International Nuclear Information System (INIS)

    Yanagisawa, Y.; Nakagome, H.; Takematsu, T.; Takao, T.; Sato, N.; Takahashi, M.; Maeda, H.

    2011-01-01

    Cleavage strength for YBCO-coated conductor is extremely low, typically 0.5 MPa. The remarkable weakness is due to cracks on the slit edge of the conductor. The cleavage stress appears on YBCO double pancake coils impregnated with epoxy. The cleavage stress should be avoided in the coil winding. Cleavage strength for an YBCO-coated conductor at 77 K was investigated with a model experiment. The nominal cleavage strength for an YBCO-coated conductor is extremely low, typically 0.5 MPa. This low nominal cleavage strength is due to stress concentration on a small part of the YBCO-coated conductor in cleavage fracture. Debonding by the cleavage stress occurs at the interface between the buffer layer and the Hastelloy substrate. The nominal cleavage strength for a slit edge of the conductor is 2.5-times lower than that for the original edge of the conductor; cracks and micro-peel existing over the slit edge reduce the cleavage strength for the slit edge. Cleavage stress and peel stress should be avoided in coil winding, as they easily delaminate the YBCO-coated conductor, resulting in substantial degradation of coil performance. These problems are especially important for epoxy impregnated YBCO-coated conductor coils. It appears that effect of cleavage stress and peel stress are mostly negligible for paraffin impregnated YBCO-coated conductor coils or dry wound YBCO-coated conductor coils.

  13. Stress-tuned conductor-polymer composite for use in sensors

    Science.gov (United States)

    Martin, James E; Read, Douglas H

    2013-10-22

    A method for making a composite polymeric material with electrical conductivity determined by stress-tuning of the conductor-polymer composite, and sensors made with the stress-tuned conductor-polymer composite made by this method. Stress tuning is achieved by mixing a miscible liquid into the polymer precursor solution or by absorbing into the precursor solution a soluble compound from vapor in contact with the polymer precursor solution. The conductor may or may not be ordered by application of a magnetic field. The composite is formed by polymerization with the stress-tuning agent in the polymer matrix. The stress-tuning agent is removed following polymerization to produce a conductor-polymer composite with a stress field that depends on the amount of stress-tuning agent employed.

  14. Study on the conductor-insulator friction at liquid helium temperature

    International Nuclear Information System (INIS)

    Batakov, Yu.P.; Kostenko, A.I.; Semenov, O.V.; Trokhachev, G.V.

    1982-01-01

    A study is made on conductor heating as a result of friction following displacements under coolina conditions close to those for conductors in superconducting magnets with cryostatic stabilization. Sliding of a 2x15 mm 2 copper plate an averawithge surface roughness of 1m over fiberglas0 μ textolite and teflon is studied. ''Sudden'' displacements are caused by application of the displacing force exceeding the static frictional force several times. If in case of friction displacements.are caused by the action of a force equal to the static frictional force, stops increasing the displacement time are possible. This may ta.ke place following the displacement of the conductor parts in the superconducting magnet coils, owing to which the displacement may turn out to be not ''sudden''. In this case in designing superconducting magnets the tolerances for conductor portion displacements, which do not affect the magnet normal operation, may be less strict

  15. Materials, Mechanics, and Patterning Techniques for Elastomer-Based Stretchable Conductors

    Directory of Open Access Journals (Sweden)

    Xiaowei Yu

    2016-12-01

    Full Text Available Stretchable electronics represent a new generation of electronics that utilize soft, deformable elastomers as the substrate or matrix instead of the traditional rigid printed circuit boards. As the most essential component of stretchable electronics, the conductors should meet the requirements for both high conductivity and the capability to maintain conductive under large deformations such as bending, twisting, stretching, and compressing. This review summarizes recent progresses in various aspects of this fascinating and challenging area, including materials for supporting elastomers and electrical conductors, unique designs and stretching mechanics, and the subtractive and additive patterning techniques. The applications are discussed along with functional devices based on these conductors. Finally, the review is concluded with the current limitations, challenges, and future directions of stretchable conductors.

  16. Development of conductor feedthrough module of LV electrical penetration assembly for research reactors

    International Nuclear Information System (INIS)

    Luo Zhiyuan; Wang Guangjin; Zhou Bin

    2007-01-01

    A LV electrical penetration assembly with perfusion sealing conductor feedthrough module was developed, which can be used for the connection of internal and external cables through the wall of the research reactor workshop. The LV electrical penetration assembly was combined with several independent modules. The maintenance and replacement of the assembly can be easily done in service. The sealing of conductor feedthrough module was achieved with the perfusion of self-extinguishing epoxy. The leakage between the conductor feedthrough module and the end plate module was blocked with rubber rings. The result of the leakage test and the electrical performance test for the samples of conductor feedthrough module satisfied the requirement of research reactor. The structure of the new electrical penetration assembly is simple and compact. It can be manufactured with mature technology and cost low price. The performance of the assembly is steady. It can be used widely in research reactors. (authors)

  17. A new Theory for frequencies computation of overhead lines with bundle conductors.

    OpenAIRE

    dubois, Hervé; Dal Maso, Filipo; Lilien, Jean-Louis

    1991-01-01

    Vertical, horizontal and torsional mechanical frequencies are studies for both single and bundle conductor lines. Models and tests are presented. These data are of particular impact on galloping phenomenon. Peer reviewed

  18. Skin effect mitigation in laser processed multi-walled carbon nanotube/copper conductors

    Science.gov (United States)

    Keramatnejad, K.; Zhou, Y. S.; Gao, Y.; Rabiee Golgir, H.; Wang, M.; Jiang, L.; Silvain, J.-F.; Lu, Y. F.

    2015-10-01

    In this study, laser-processed multi-walled carbon nanotube (MWCNT)/Cu conductors are introduced as potential passive components to mitigate the skin effect of Cu at high frequencies (0-10 MHz). Suppressed skin effect is observed in the MWCNT/Cu conductors compared to primitive Cu. At an AC frequency of 10 MHz, a maximum AC resistance reduction of 94% was observed in a MWCNT/Cu conductor after being irradiated at a laser power density of 189 W/cm2. The reduced skin effect in the MWCNT/Cu conductors is ascribed to the presence of MWCNT channels which are insensitive to AC frequencies. The laser irradiation process is observed to play a crucial role in reducing contact resistance at the MWCNT-Cu interfaces, removing impurities in MWCNTs, and densifying MWCNT films.

  19. Skin effect mitigation in laser processed multi-walled carbon nanotube/copper conductors

    Energy Technology Data Exchange (ETDEWEB)

    Keramatnejad, K.; Zhou, Y. S.; Gao, Y.; Rabiee Golgir, H.; Wang, M.; Lu, Y. F., E-mail: ylu2@unl.edu [Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0511 (United States); Jiang, L. [School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081 (China); Silvain, J.-F. [Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB-CNRS) 87, Avenue du Docteur Albert Schweitzer F-33608 Pessac Cedex (France)

    2015-10-21

    In this study, laser-processed multi-walled carbon nanotube (MWCNT)/Cu conductors are introduced as potential passive components to mitigate the skin effect of Cu at high frequencies (0–10 MHz). Suppressed skin effect is observed in the MWCNT/Cu conductors compared to primitive Cu. At an AC frequency of 10 MHz, a maximum AC resistance reduction of 94% was observed in a MWCNT/Cu conductor after being irradiated at a laser power density of 189 W/cm{sup 2}. The reduced skin effect in the MWCNT/Cu conductors is ascribed to the presence of MWCNT channels which are insensitive to AC frequencies. The laser irradiation process is observed to play a crucial role in reducing contact resistance at the MWCNT-Cu interfaces, removing impurities in MWCNTs, and densifying MWCNT films.

  20. Skin effect mitigation in laser processed multi-walled carbon nanotube/copper conductors

    International Nuclear Information System (INIS)

    Keramatnejad, K.; Zhou, Y. S.; Gao, Y.; Rabiee Golgir, H.; Wang, M.; Lu, Y. F.; Jiang, L.; Silvain, J.-F.

    2015-01-01

    In this study, laser-processed multi-walled carbon nanotube (MWCNT)/Cu conductors are introduced as potential passive components to mitigate the skin effect of Cu at high frequencies (0–10 MHz). Suppressed skin effect is observed in the MWCNT/Cu conductors compared to primitive Cu. At an AC frequency of 10 MHz, a maximum AC resistance reduction of 94% was observed in a MWCNT/Cu conductor after being irradiated at a laser power density of 189 W/cm 2 . The reduced skin effect in the MWCNT/Cu conductors is ascribed to the presence of MWCNT channels which are insensitive to AC frequencies. The laser irradiation process is observed to play a crucial role in reducing contact resistance at the MWCNT-Cu interfaces, removing impurities in MWCNTs, and densifying MWCNT films

  1. Work in the U.K. on filamentary A15 conductor development

    International Nuclear Information System (INIS)

    Lee, J.A.; Scott, C.A.

    1980-07-01

    Work on Nb 3 Sn conductor development work began at Harwell in 1967 with work on stable filamentary Nb 3 Sn composites starting in 1969. This lead to a series of small magnets built at the Rutherford laboratory, using conductors incorporating high purity copper regions protected by diffusion barriers of both tantalum and phosphorus poisoned niobium, and the Wind-react technique for magnet construction was established. A magnet development programme lead to the construction of a 450mmx50mm hexapole magnet. IMI's parallel conductor programme developed tantalum diffusion barriers and used a hot extrusion first stage. The present position on conductor development is the result of a unification in 1979 of technical and commercial interests including university programmes. This current position is reported. (U.K.)

  2. Quantitative impedance analysis of solid ionic conductors: Effects of electrode polarization

    Czech Academy of Sciences Publication Activity Database

    Patil, D.; Shimakawa, K.; Zima, Vítězslav; Wágner, T.

    2014-01-01

    Roč. 115, č. 14 (2014), "143707-1"-"143707-6" ISSN 0021-8979 Institutional support: RVO:61389013 Keywords : impedance * conductivity * ion conductors Subject RIV: CA - Inorganic Chemistry Impact factor: 2.183, year: 2014

  3. AC magnetization loss characteristics of HTS coated-conductors with magnetic substrates

    International Nuclear Information System (INIS)

    Tsukamoto, O.; Liu, M.; Odaka, S.; Miyagi, D.; Ohmatsu, K.

    2007-01-01

    AC magnetization loss characteristics of an HTS coated tape conductor with magnetic substrate subjected to an external AC magnetic field were investigated. The external magnetic field was perpendicular or parallel to the wide face of the tape conductor. Magnetization losses in the conductor and in the magnetic substrate itself without the superconductor layer, were measured by electric and calorimetric methods. The influence of the magnetic property of the substrate was strongly dependent on the direction of the external magnetic field. When the external magnetic field was perpendicular, magnetic property of the substrate did not affect the magnetization loss characteristics. This result suggests that the magnetization losses can be reduced by subdivisions of the superconducting layers even in the case of magnetic substrate conductors. When the external magnetic field was parallel, the magnetization losses were dominated by the losses in the magnetic substrate. Therefore, to reduce the magnetization losses in this case, reduction of magnetization losses in the substrate is necessary

  4. Cube-textured metal substrates for reel-to-reel processing of coated conductors

    DEFF Research Database (Denmark)

    Wulff, Anders Christian

    This thesis presents the results of a study aimed at investigating important fabrication aspects of reel-to-reel processing of metal substrates for coated conductors and identifying a new substrate candidate material with improved magnetic properties. The eect of mechanical polishing on surface...... texture and the fraction of low angle grain boundaries. Finally, a Ni-5Cu-5W substrate may be a good candidate material as a substrate in future coated conductors....

  5. Bipolar energy-loss measurements on cryostable, low-loss conductors

    Energy Technology Data Exchange (ETDEWEB)

    Wollan, J.J.

    1981-01-01

    Losses have been measured on a prototype conductor for the 20 MJ coil for conditions which simulate closely the actual coil field sweep. The data on the prototype II conductor indicates coil losses which exceed the coil specification. The application of certain correction factors reduces the projected losses within the specification for a 2 s reversal but not for a 1 s reversal. Verification of these corrections await measurements on the actual strand and completion of coil construction and testing.

  6. Transparent conductors based on microscale/nanoscale materials for high performance devices

    Science.gov (United States)

    Gao, Tongchuan

    Transparent conductors are important as the top electrode for a variety of optoelectronic devices, including solar cells, light-emitting diodes (LEDs), at panel displays, and touch screens. Doped indium tin oxide (ITO) thin films are the predominant transparent conductor material. However, ITO thin films are brittle, making them unsuitable for the emerging flexible devices, and suffer from high material and processing cost. In my thesis, we developed a variety of transparent conductors toward a performance comparable with or superior to ITO thin films, with lower cost and potential for scalable manufacturing. Metal nanomesh (NM), hierarchical graphene/metal microgrid (MG), and hierarchical metal NM/MG materials were investigated. Simulation methods were used as a powerful tool to predict the transparency and sheet resistance of the transparent conductors by solving Maxwell's equations and Poisson's equation. Affordable and scalable fabrication processes were developed thereafter. Transparent conductors with over 90% transparency and less than 10 O/square sheet resistance were successfully fabricated on both rigid and flexible substrates. Durability tests, such as bending, heating and tape tests, were carried out to evaluate the robustness of the samples. Haze factor, which characterizes how blurry a transparent conductor appears, was also studied in-depth using analytical calculation and numerical simulation. We demonstrated a tunable haze factor for metal NM transparent conductors and analyzed the principle for tuning the haze factor. Plasmonic effects, excited by some transparent conductors, can lead to enhanced performance in photovoltaic devices. We systematically studied the effect of incorporating metal NM into ultrathin film silicon solar cells using numerical simulation, with the aid of optimization algorithms to reduce the optimization time. Mechanisms contributing to the enhanced performance were then identified and analyzed. Over 72% enhancement in short

  7. Qualification of the US Made Conductors for ITER TF Magnet System

    International Nuclear Information System (INIS)

    Martovetsky, Nicolai N.; Hatfield, Daniel R.; Miller, John R.; Bruzzone, P.; Stepanov, B.; Seber, B.

    2010-01-01

    The US Domestic Agency (USDA) is one of the six suppliers of the Toroidal Field (TF) conductor for the International Thermonuclear Experimental Reactor (ITER). In order to qualify conductors according to ITER requirements we prepared several lengths of the CICC and short samples for testing in the SULTAN facility in CRPP, Switzerland. We also fully characterized the strands that were used in these SULTAN samples. Fabrication experience and test results are presented and discussed.

  8. Transport and magnetism in the organic conductors in relation to one dimension localization theory

    International Nuclear Information System (INIS)

    Zuppiroli, L.

    1985-09-01

    On the one side all states are exponentially localized in one dimension, on the other side most of the transport properties of quasi-one-dimensional organic conductors are Drude-like. This apparent contradiction is solved by revisiting the main experimental results concerning disordered organic conductors and by comparing them to the most relevant theories, especially those which take into account electron-phonon an electron-electron interactions [fr

  9. Measurements of residual deformations of steel-aluminum conductors in operating overhead lines

    Energy Technology Data Exchange (ETDEWEB)

    Durov, E.V.; Kesel' man, L.M.; Treiger, A.S.

    1982-12-01

    Experience in the operation of overhead power lines using steel-aluminum conductors is presented. Measurements were taken on the residual deformation of the steel-aluminum lines to determine the amount of sag increase and to forecast this increase for the entire period of operation. It is recommended that the work on measuring the residual deformation in the power lines be extended to a broader range of operating conditions such as conductors, spans, and climate conditions.

  10. Raman scattering studies of mobile ions in superionic conductor hollandites

    International Nuclear Information System (INIS)

    Shibata, Y.; Suemoto, T.; Ishigame, M.

    1986-01-01

    The Raman spectra of the superionic conductors K/sub 1.6/Mg/sub 0.8/Ti/sub 7.2/O 16 , Cs/sub 1.2/Mg/sub 0.6/Ti/sub 7.4/O 16 , and (KTl)/sub 1.6/Mg/sub 0.8/Ti/sub 7.2/O 16 are measured in the frequency range from 5 to 1000 cm -1 . In the range from 100 to 1000 cm -1 Raman spectra hardly show alkali ion dependence. On the contrary, in the frequency range from 5 to 100 cm -1 , an additional Raman band is observed. This Raman band shows alkali ion dependence. By using the Frenkel-Kontorova model for the hollandite crystal with the given configuration of the mobile ions, it is found that the dependence of vibrational frequency of mobile ions with kinds of alkali ion is well explained and that the concept of 'super unit cell' that is introduced by Beyeler is very useful to explain the Raman bands which are observed below 100 cm -1 in hollandite crystals. (author)

  11. Aluminum alloy production for the reinforcement of the CMS conductor

    CERN Document Server

    Sequeira-Lopes-Tavares, S; Campi, D; Curé, B; Horváth, I L; Riboni, P; Sgobba, Stefano; Smith, R P

    2002-01-01

    The Compact Muon Solenoid (CMS) is one of the general-purpose detectors to be provided for the Large Hadron Collider (LHC) project at CERN. The design field of the CMS superconducting magnet is 4 T, the magnetic length is 12.5 m and the free bore is 6 m. To reinforce the high-purity (99.998%) Al-stabilized conductor of the magnet against the magnetic loadings experienced during operation at 4.2 K, two continuous sections of Al-alloy (AA) reinforcement are Electron Beam (EB) welded to it. The reinforcements have a section of 24*18 mm and are produced in continuous 2.55 km lengths. The alloy EN AW-6082 has been selected for the reinforcement due to its excellent extrudability, high strength in the precipitation hardened states, high toughness and strength at cryogenic temperature and good EB weldability. Each of the continuous lengths of the reinforcement is extruded billet on billet and press quenched on-line from the extrusion temperature in an industrial extrusion plant. In order to insure the ready EB welda...

  12. Liquid conductor model of instabilities in a pinched discharge

    Energy Technology Data Exchange (ETDEWEB)

    Dattnery, A; Lehnert, B [Dept. of Electronics, Royal Institute of Technology, Stockholm (Sweden); Lundquist, S [Swedish State Power Board (Sweden)

    1958-07-01

    The pinched gas discharge experiments seem to have been handicapped by the great speed with which the instability develops as well as by the light coming from impurities instead of the main body of pinched gas. In the present work a liquid conductor is used in order to study the structure of the instabilities. The study of a pinch was made with and without the axial magnetic field. In cases with a magnetic field, the currents and fields were chosen so as to give a longitudinal magnetic field equal to or three times the azimuthal field at the boundary of the mercury stream. The study of the results shows that in the case without an external magnetic field there is a similarity between the behavior of the pinch in a stream of mercury and in an ionized gas column. The stabilizing action of the surface tension is small and the instabilities develop easily. The case with an external magnetic field is more complicated. The magnetic lines of force are not frozen into the medium; they can 'escape' from the medium. In this case the magnetic field has no stabilizing effect. The influence of conducting walls around the mercury column will be studied in forthcoming experiments.

  13. Tunable Broadband Nanocarbon Transparent Conductor by Electrochemical Intercalation.

    Science.gov (United States)

    Wan, Jiayu; Xu, Yue; Ozdemir, Burak; Xu, Lisha; Sushkov, Andrei B; Yang, Zhi; Yang, Bao; Drew, Dennis; Barone, Veronica; Hu, Liangbing

    2017-01-24

    Optical transparent and electrical conducting materials with broadband transmission are important for many applications in optoelectronic, telecommunications, and military devices. However, studies of broadband transparent conductors and their controlled modulation are scarce. In this study, we report that reversible transmittance modulation has been achieved with sandwiched nanocarbon thin films (containing carbon nanotubes (CNTs) and reduced graphene oxide (rGO)) via electrochemical alkali-ion intercalation/deintercalation. The transmittance modulation covers a broad range from the visible (450 nm) to the infrared (5 μm), which can be achieved only by rGO rather than pristine graphene films. The large broadband transmittance modulation is understood with DFT calculations, which suggest a decrease in interband transitions in the visible range as well as a reduced reflection in the IR range upon intercalation. We find that a larger interlayer distance in few-layer rGO results in a significant increase in transparency in the infrared region of the spectrum, in agreement with experimental results. Furthermore, a reduced plasma frequency in rGO compared to few-layer graphene is also important to understand the experimental results for broadband transparency in rGO. The broadband transmittance modulation of the CNT/rGO/CNT systems can potentially lead to electrochromic and thermal camouflage applications.

  14. The construction of the ATLAS semi-conductor tracker

    International Nuclear Information System (INIS)

    Jones, Tim

    2006-01-01

    The ATLAS (A Toroidal LHC ApparatuS) experiment at the Large Hadron Collider (LHC) at CERN has been designed to explore physics at the TeV energy scale and will be commissioned in 2007. In the innermost region of the experiment is a charged particle tracker, the Inner Detector of which the Semiconductor Tracker (SCT) is a major component. The SCT comprises a central barrel section enclosed by two endcaps (A and C). The construction of the major components of the ATLAS Semi-conductor tracker (SCT) is now nearing completion. Following a brief description of the design of the SCT, the logistics and organisation of the construction phase of the project are discussed. Central to the delivery of a high quality detector is the testing of large numbers of modules both during assembly and after they are mounted on their final support structures. The results of these tests for endcap C are presented showing that the electrical performance of the 988 modules to be installed in ATLAS is compatible with the specifications required

  15. Eddy damping effect of additional conductors in superconducting levitation systems

    Science.gov (United States)

    Jiang, Zhao-Fei; Gou, Xiao-Fan

    2015-12-01

    Passive superconducting levitation systems consisting of a high temperature superconductor (HTSC) and a permanent magnet (PM) have demonstrated several fascinating applications such as the maglev system, flywheel energy storage. Generally, for the HTSC-PM levitation system, the HTSC with higher critical current density Jc can obtain larger magnetic force to make the PM levitate over the HTSC (or suspended below the HTSC), however, the process of the vibration of the levitated PM, provides very limited inherent damping (essentially hysteresis). To improve the dynamic stability of the levitated PM, eddy damping of additional conductors can be considered as the most simple and effective approach. In this article, for the HTSC-PM levitation system with an additional copper damper attached to the HTSC, we numerically and comprehensively investigated the damping coefficient c, damping ratio, Joule heating of the copper damper, and the vibration frequency of the PM as well. Furthermore, we comparatively studied four different arrangements of the copper damper, on the comprehensive analyzed the damping effect, efficiency (defined by c/VCu, in which VCu is the volume of the damper) and Joule heating, and finally presented the most advisable arrangement.

  16. Progress toward a practical Nb--Ge conductor

    International Nuclear Information System (INIS)

    Braginski, A.I.; Gavaler, J.R.; Roland, G.W.; Daniel, M.R.; Janocko, M.A.; Santhanam, A.T.

    1976-01-01

    Properties of high-T/sub c/ Nb--Ge films deposited by sputtering and by chemical vapor deposition (CVD) have been investigated. Results of sputtering in the presence of controlled levels of O 2 , N 2 , Si, and of reactive sputtering in Ar--GeH 4 , suggest that the high-T/sub c/ A15 phase is impurity- or defect-stabilized. In CVD deposits two tetragonal modifications were found: sigma and T2, the latter probably stabilized by Cl 2 . High critical current densities, J/sub c/ (H, T) of fine-grained sputtered films are attributed to flux pinning on A15 grain boundaries. In coarse-grained CVD films high self-field J/sub c/'s, 10 6 to 10 7 A cm -2 at T = 4.2 0 K, are attributed to pinning on dispersed sigma-phase. Comparably high J/sub c/'s were also obtained in CVD A15 films doped with impurities. Low field ac losses p (H, T) were correlated with J/sub c/ and coating geometries. The feasibility of fabricating multifilamentary composite conductors by CVD was demonstrated experimentally and a fabrication process for long Nb 3 Ge CVD tapes is being developed

  17. Scattering theory of nonlinear thermoelectricity in quantum coherent conductors.

    Science.gov (United States)

    Meair, Jonathan; Jacquod, Philippe

    2013-02-27

    We construct a scattering theory of weakly nonlinear thermoelectric transport through sub-micron scale conductors. The theory incorporates the leading nonlinear contributions in temperature and voltage biases to the charge and heat currents. Because of the finite capacitances of sub-micron scale conducting circuits, fundamental conservation laws such as gauge invariance and current conservation require special care to be preserved. We do this by extending the approach of Christen and Büttiker (1996 Europhys. Lett. 35 523) to coupled charge and heat transport. In this way we write relations connecting nonlinear transport coefficients in a manner similar to Mott's relation between the linear thermopower and the linear conductance. We derive sum rules that nonlinear transport coefficients must satisfy to preserve gauge invariance and current conservation. We illustrate our theory by calculating the efficiency of heat engines and the coefficient of performance of thermoelectric refrigerators based on quantum point contacts and resonant tunneling barriers. We identify, in particular, rectification effects that increase device performance.

  18. Optimization study of normal conductor tokamak for commercial neutron source

    Science.gov (United States)

    Fujita, T.; Sakai, R.; Okamoto, A.

    2017-05-01

    The optimum conceptual design of tokamak with normal conductor coils was studied for minimizing the cost for producing a given neutron flux by using a system code, PEC. It is assumed that the fusion neutrons are used for burning transuranics from the fission reactor spent fuel in the blanket and a fraction of the generated electric power is circulated to opearate the tokamak with moderate plasma fusion gain. The plasma performance was assumed to be moderate ones; {β\\text{N}}~∼ ~3{--}4 in the aspect ratio A~=~2{--}3 and {{H}98y2}~=~1 . The circulating power is an important factor affecting the cost. Though decreasing the aspect ratio is useful to raise the plasma beta and decrease the toroidal field, the maximum field in the coil starts to rise in the very low aspect ratio range and then the circulating power increases with decrease in the plasma aspect ratio A below A~∼ ~2 , while the construction cost increases with A . As a result, the cost per neutron has its minimum around A~∼ ~2.2 , namely, between ST and the conventional tokamak. The average circulating power fraction is expected to be ~51%.

  19. Long Gd-123 coated conductor by PLD method

    International Nuclear Information System (INIS)

    Fuji, H.; Igarashi, M.; Hanada, Y.; Miura, T.; Hanyu, S.; Kakimoto, K.; Iijima, Y.; Saitoh, T.

    2008-01-01

    We have developed long Gd-123 coated conductors by ion-beam-assisted deposition (IBAD) and pulsed-laser-deposition (PLD) method. Recently, large-scale reel-to-reel apparatus with the 110 cm x 15 cm assisting ion source was introduced to IBAD system. It was enable to produce 500 m-class IBAD-Gd 2 Zr 2 O 7 (GZO) tapes with Δφ of below 15 deg. and high throughputs of 3 m/h. Furthermore, apparatus with multi-lane and laser scanning was introduced to PLD system. As a result, end to end I c of 318 A were obtained for a 201.5 m long tape, and I c x L values were 64,077 Am. Furthermore, 500 m-class deposition was carried out by improving PLD conditions. As a result, I c x L values of 112,166 Am was obtained and it's a world record on August 2007. In the short samples, I c of over 500 A was obtained with Gd-123 thickness of 2.0 μm and over 100 A was obtained in magnetic field of 3 T, perpendicular to c-axis

  20. Field and electric potential of conductors with fractal geometry

    Energy Technology Data Exchange (ETDEWEB)

    Assis, Thiago A de; Mota, Fernando de B; Miranda, Jose G V; Andrade, Roberto F S; Castilho, Caio M C de [Instituto de Fisica, Universidade Federal da Bahia, Campus Universitario da Federacao, 40210-340, Salvador (Brazil)

    2007-11-28

    In this study, the behavior of the electric field and its potential are investigated in a region bounded by a rough fractal surface and a distant plane. Both boundaries, maintained at distinct potential values, are assumed to be conductors and, as such, the electric potential is obtained by numerically solving Laplace's equation subject to the appropriate Dirichlet's condition. The rough boundaries, generated by the ballistic deposition and fractal Brownian motion methods, are characterized by the values of the surface roughness W and the local fractal dimension df = 3-{alpha}, where {alpha} is the usual roughness exponent. The equipotential surfaces, obtained from Laplace's equation, are characterized by these same parameters. Results presented show how df depends on the potential value, on the method used to generate the boundary and on W. The behavior of the electric field with respect to the equipotential surface is also considered. Its average intensity was found to increase as a function of the average distance from the equipotential to the fractal boundary; however, its intensity reaches a maximum before decreasing towards an asymptotic constant value, an effect that increases as the value of W increases.

  1. Field and electric potential of conductors with fractal geometry

    International Nuclear Information System (INIS)

    Assis, Thiago A de; Mota, Fernando de B; Miranda, Jose G V; Andrade, Roberto F S; Castilho, Caio M C de

    2007-01-01

    In this study, the behavior of the electric field and its potential are investigated in a region bounded by a rough fractal surface and a distant plane. Both boundaries, maintained at distinct potential values, are assumed to be conductors and, as such, the electric potential is obtained by numerically solving Laplace's equation subject to the appropriate Dirichlet's condition. The rough boundaries, generated by the ballistic deposition and fractal Brownian motion methods, are characterized by the values of the surface roughness W and the local fractal dimension df = 3-α, where α is the usual roughness exponent. The equipotential surfaces, obtained from Laplace's equation, are characterized by these same parameters. Results presented show how df depends on the potential value, on the method used to generate the boundary and on W. The behavior of the electric field with respect to the equipotential surface is also considered. Its average intensity was found to increase as a function of the average distance from the equipotential to the fractal boundary; however, its intensity reaches a maximum before decreasing towards an asymptotic constant value, an effect that increases as the value of W increases

  2. Study of superionic conductors dynamics by continued diffusion model

    International Nuclear Information System (INIS)

    Bennai, M.

    1993-12-01

    The superionic conductors form a special category of solids characterized by their remarkable transport properties and are in general, Simplified as being constituted by the superposition of two inter penetrable crystal lattices. The ions of the first one form a rigid structure through which the other ions of opposite charge diffuse in quasi-liquid way. Basing on experimental and theoretical arguments, it was proved necessary to adopt a model of N-body continued diffusion which the basic theory is that of brownian movement. This thesis deals with the study of the dynamic structure factor S (q,w) and its line half width by the method of development in continued fractions issued from the Mori theory. With regard to the analytical difficulty met at the time of the static correlations functions calculation, the homogeneous approximation was applied and the notion of effective strength was introduced. So, it was obtained general relationships which give the static correlation functions, only in term of the static structure factor of liquids and effective potential. 98 refs.; 22 figs. (F.M.)

  3. Development of long GdBCO coated conductor using the IBAD/MPMT-PLD method

    International Nuclear Information System (INIS)

    Ibi, A; Fukushima, H; Yamada, Y; Miyata, S; Kuriki, R; Takahashi, K; Shiohara, Y

    2006-01-01

    We have developed long GdBa 2 Cu 3 O 7-X (GdBCO) coated conductors by a multi-plume and multi-turn pulsed laser deposition (MPMT-PLD) method and have successfully fabricated 32 and 60.7 m long GdBCO coated conductors with a high critical current, I c , and high deposition rate. The I c of the 32 and 60.7 m long GdBCO coated conductors were 205 A (J c = 1.36 MA cm -2 ) and 183 A (J c = 1.45 MA cm -2 ), respectively, at 77 K and 0 T. In addition, they exhibited higher I c values in a magnetic field than a YBa 2 Cu 3 O 7-X (YBCO) coated conductor: typically 20 A at 77 K and 3 T while the value for a YBCO coated conductor is 8 A. These high I c values are due to the smaller number of a-axis oriented grains in GdBCO than in YBCO. Furthermore, the speed of production of the GdBCO layer was increased to 10 m h -1 while that of the former YBCO coated conductor was 3.75 m h -1 . The material yield of long GdBCO layers using the MPMT-PLD method was about 26-28%. The high I c of GdBCO in a magnetic field, the high production rate and the high material yield are promising for applications

  4. Transport losses in single and assembled coated conductors with textured-metal substrate with reduced magnetism

    International Nuclear Information System (INIS)

    Amemiya, N.; Jiang, Z.; Li, Z.; Nakahata, M.; Kato, T.; Ueyama, M.; Kashima, N.; Nagaya, S.; Shiohara, S.

    2008-01-01

    Transport losses in a coated conductor with a textured-metal substrate with reduced magnetism were studied experimentally. The substrate is with a clad structure, and HoBCO superconductor layer is deposited on the substrate with buffer layers. The measured transport loss of a sample whose critical current is 126.0 A falls between Norris's strip value and Norris's ellipse value. The increase in the measured transport loss from Norris's strip value can be attributed to its non-uniform lateral J c distribution. The same buffered clad tape was placed under an IBAD-MOCVD coated conductor with a non-magnetic substrate, and its transport loss was measured. The comparison between the measured transport loss of this sample and that of the identical IBAD-MOCVD coated conductor without the buffered clad tape indicates that the increase in the transport loss due to this buffered clad tape is small. The transport losses of hexagonal assemblies of IBAD-MOCVD coated conductors, whose structure simulates that of superconducting power transmission cables, were also measured where the buffered clad tapes were under-lied or over-lied on the coated conductors. The increase in the transport loss of hexagonal assemblies of coated conductors due to the buffered clad tapes is at an allowable level

  5. Test of 60 kA coated conductor cable prototypes for fusion magnets

    Science.gov (United States)

    Uglietti, D.; Bykovsky, N.; Sedlak, K.; Stepanov, B.; Wesche, R.; Bruzzone, P.

    2015-12-01

    Coated conductors could be promising materials for the fabrication of the large magnet systems of future fusion devices. Two prototype conductors (flat cables in steel conduits), each about 2 m long, were manufactured using coated conductor tapes (4 mm wide) from Super Power and SuperOx, with a total tape length of 1.6 km. Each flat cable is assembled from 20 strands, each strand consisting of a stack of 16 tapes surrounded by two half circular copper profiles, twisted and soldered. The tapes were measured at 12 T and 4.2 K and the results of the measurements were used for the assessment of the conductor electromagnetic properties at low temperature and high field. The two conductors were assembled together in a sample that was tested in the European Dipole (EDIPO) facility. The current sharing temperatures of the two conductors were measured at background fields from 8 T up to 12 T and for currents from 30 kA up to 70 kA: the measured values are within a few percent of the values expected from the measurements on tapes (short samples). After electromagnetic cycling, T cs at 12 T and 50 kA decreased from about 12 K to 11 K (about 10%), corresponding to less than 3% of I c.

  6. An A15 conductor design and its implications for the NET-II TF coils

    International Nuclear Information System (INIS)

    Fluekiger, R.; Arendt, F.; Hofmann, A.; Jeske, U.; Juengst, K.P.; Komarek, P.; Krauth, H.; Lehmann, W.; Luehning, J.; Manes, B.; Maurer, W.; Nyilas, A.; Specking, W.; Turowski, P.; Zehlein, H.

    1985-06-01

    The paper describes the results of studies for a NET toroidal field coil conductor carried out at KfK-Karlsruhe. The conductor concept is based on the same design principles as used in the Euratom-LCT coil, well proven in all conductor tests and the domestic tests of the coil. These principles are applied to the peculiarities of Nb 3 Sn for a rated current of 20 kA at 12 T, taking into account ac losses and nuclear heating. A flat Nb 3 Sn cable is soldered to a surrounding CuNi tape after reaction. Around this rectangular conductor core, Cu profiles are cabled on distance by the Roebel-process and subsequently soldered onto the CuNi tape. The whole system is surrounded by a steel conduit. The conductor data result from electric, thermohydraulic and stability calculations as well as mechanical evaluations. Expected fabrication processes are discussed, and measurements on a first simplified subsize conductor model are presented. (orig.) [de

  7. Powder-in-tube (PIT) Nb$_{3}$Sn conductors for high-field magnets

    CERN Document Server

    Lindenhovius, J L H; den Ouden, A; Wessel, W A J; ten Kate, H H J

    2000-01-01

    New Nb/sub 3/Sn conductors, based on the powder-in-tube (PIT) process, have been developed for application in accelerator magnets and high-field solenoids. For application in accelerator magnets, SMI has developed a binary 504 filament PIT conductor by optimizing the manufacturing process and adjustment of the conductor lay-out. It uniquely combines a non-copper current density of 2680 A/mm/sup 2/@10 T with an effective filament diameter of about 20 mu m. This binary conductor may be used in a 10 T, wide bore model separator dipole magnet for the LHC, which is being developed by a collaboration of the University of Twente and CERN. A ternary (Nb/7.5wt%Ta)/sub 3/Sn conductor containing 37 filaments is particularly suited for application in extremely high-field superconducting solenoids. This wire features a copper content of 43%, a non-copper current density of 217 A/mm/sup 2/@20 T and a B/sub c2/ of 25.6 T. The main issues and the experimental results of the development program of PIT Nb/sub 3/Sn conductors a...

  8. Manufacturing and test of 2G-HTS coils for rotating machines: Challenges, conductor requirements, realization

    International Nuclear Information System (INIS)

    Oomen, Marijn; Herkert, Werner; Bayer, Dietmar; Kummeth, Peter; Nick, Wolfgang; Arndt, Tabea

    2012-01-01

    We investigate the use of 2nd-generation High-Temperature Superconductors (2G-HTSs) in the rotors of electrical motors and generators. For these devices the conductor must be wound into robust impregnated coils, which are operated in vacuum at temperatures around 30 K, in strong magnetic fields of about 2T. Differences in thermal contraction between the coil former, conductor constituents, impregnation resin, bandage and heat-sink materials (assembled at room temperature) cause mechanical stresses at operating temperature. Rotating-machine operation adds Lorentz forces and challenging centripetal accelerations up to thousands of g. Second generation-HTS conductors withstand large tensile stresses in axial direction and compression in normal direction. However, shear stresses, axial compression, and tension normal to the conductor can cause degradation in superconducting properties. Such stresses can be mitigated by correct choice of materials, coil lay-out and manufacturing process. A certain stress level will remain, which the conductor must withstand. We have manufactured many impregnated round and race-track coils, using different 2G-HTS conductors, and tested them at temperatures from 25 K to 77 K. Degradation of the superconductor in early coils was traced to the mentioned differences in thermal contraction, and was completely avoided in coils produced later. We will discuss appropriate coil-winding techniques to assure robust and reliable superconductor performance.

  9. Benzothienobenzothiophene-Based Molecular Conductors: High Conductivity, Large Thermoelectric Power Factor, and One-Dimensional Instability.

    Science.gov (United States)

    Kiyota, Yasuhiro; Kadoya, Tomofumi; Yamamoto, Kaoru; Iijima, Kodai; Higashino, Toshiki; Kawamoto, Tadashi; Takimiya, Kazuo; Mori, Takehiko

    2016-03-23

    On the basis of an excellent transistor material, [1]benzothieno[3,2-b][1]benzothiophene (BTBT), a series of highly conductive organic metals with the composition of (BTBT)2XF6 (X = P, As, Sb, and Ta) are prepared and the structural and physical properties are investigated. The room-temperature conductivity amounts to 4100 S cm(-1) in the AsF6 salt, corresponding to the drift mobility of 16 cm(2) V(-1) s(-1). Owing to the high conductivity, this salt shows a thermoelectric power factor of 55-88 μW K(-2) m(-1), which is a large value when this compound is regarded as an organic thermoelectric material. The thermoelectric power and the reflectance spectrum indicate a large bandwidth of 1.4 eV. These salts exhibit an abrupt resistivity jump under 200 K, which turns to an insulating state below 60 K. The paramagnetic spin susceptibility, and the Raman and the IR spectra suggest 4kF charge-density waves as an origin of the low-temperature insulating state.

  10. Preparation and characterization of a neutral π-radical molecular conductor

    International Nuclear Information System (INIS)

    Barclay, T.M.; Cordes, A.W.; Haddon, R.C.; Itkis, M.E.; Oakley, R.T.; Reed, R.W.; Zhang, H.

    1999-01-01

    The synthesis and solid-state characterization of the heterocyclic π-radical 1,2,5-thiadiazolo[3,4-b]-1,2,3-dithiazolo[3,4-b]pyrazin-2-yl, 1,2,3-TDTA, is described. The ESR spectrum of 1,2,3-TDTA (in CH 2 -Cl 2 , 293 K, g = 2.009) confirms a highly delocalized spin distribution, with observable hyperfine coupling to all five nitrogen atoms of the tricyclic molecule (a N = 0.514, 0.343, 0.109, 0.051, and 0.045 mT). While chemical and electrochemical oxidation (E 1/2 (ox) = 1.14 V vs SCE) of 1,2,3-TDTA requires relatively harsh conditions, reduction is extremely facile (E 1/2 (red) = 0.15 V vs SCE). More importantly both the observed cell potential E cell and computed (MNDO) gas-phase enthalpy ΔH disp for the disproportionation of this and other 1,2,3-dithiazolyls are significantly lower than those observed for their 1,3,2-isomers. Crystals of 1,2,3-TDTA are monoclinic P2 1 /n, with a = 6.6749(16) A, b = 11.7178(14) angstrom, c = 8.6148(14) angstrom, β = 103.297(16)degree, and Z = 4. The crystal structure consists of slipped stacks of heat-to-tail (centrosymmetric) π-dimers. The closest intradimer S---S contact (S2---S3) is 3.2331(15) angstrom. Variable-temperature magnetic susceptibility measurements establish that 1,2,3-TDTA is essentially diamagnetic at room temperature. The magnetic data, along with the results of variable-temperature single-crystal conductivity measurements (1,2,3-TDTA exhibits a room-temperature conductivity σ = 1 x 10 -4 S cm -1 ), are interpreted in terms of one-dimensional hopping mechanism for charge transport

  11. Eddy damping effect of additional conductors in superconducting levitation systems

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Zhao-Fei; Gou, Xiao-Fan, E-mail: xfgou@hhu.edu.cn

    2015-12-15

    Highlights: • In this article, for the eddy current damper attached to the HTSC, we • quantitatively investigated the damping coefficient c, damping ratio, Joule heating of the copper damper, and the vibration frequency of the PM as well. • presented four different arrangements of the copper damper, and comparatively studied their damping effects and Joule heating, and finally proposed the most advisable arrangement. - Abstract: Passive superconducting levitation systems consisting of a high temperature superconductor (HTSC) and a permanent magnet (PM) have demonstrated several fascinating applications such as the maglev system, flywheel energy storage. Generally, for the HTSC–PM levitation system, the HTSC with higher critical current density J{sub c} can obtain larger magnetic force to make the PM levitate over the HTSC (or suspended below the HTSC), however, the process of the vibration of the levitated PM, provides very limited inherent damping (essentially hysteresis). To improve the dynamic stability of the levitated PM, eddy damping of additional conductors can be considered as the most simple and effective approach. In this article, for the HTSC–PM levitation system with an additional copper damper attached to the HTSC, we numerically and comprehensively investigated the damping coefficient c, damping ratio, Joule heating of the copper damper, and the vibration frequency of the PM as well. Furthermore, we comparatively studied four different arrangements of the copper damper, on the comprehensive analyzed the damping effect, efficiency (defined by c/V{sub Cu}, in which V{sub Cu} is the volume of the damper) and Joule heating, and finally presented the most advisable arrangement.

  12. Current distribution in Cable-In-Conduit Conductors

    International Nuclear Information System (INIS)

    Ferri, M.A.

    1994-05-01

    A numerical study of the current distribution in Cable-In-Conduit Conductors (CICC's) experiencing linearly ramping transport currents and transverse magnetic fields was conducted for both infinitely long, periodic cables and finite length cables terminated in low resistance joints. The goal of the study was to gain insight into the phenomenon known as Ramp Rate Limitation, an as yet unexplained correspondence between maximum attainable current and the ramp time taken to reach that current in CICC superconducting magnets. A discrete geometric model of a 27 strand multiply twisted CICC was developed to effectively represent the flux linkages, mutual inductances, and resistive contact points between the strands of an experimentally tested cable. The results of the numerical study showed that for fully periodic cables, the current imbalances due to ramping magnetic fields and ramping transport currents are negligible in the range of experimentally explored operating conditions. For finite length, joint terminated cables, however, significant imbalances can exist. Unfortunately, quantitative results are limited by a lack of knowledge of the transverse resistance between strands in the joints. Nonetheless, general results are presented showing the dependency of the imbalance on cable length, ramp time, and joint resistance for both ramping transverse magnet fields and ramping transport currents. At the conclusion of the study, it is suggested that calculated current imbalances in a finite length cable could cause certain strands to prematurely ''quench'' -- become non-superconducting --thus leading to an instability for the entire cable. This numerically predicted ''current imbalance instability'' is compared to the experimentally observed Ramp Rate Limitation for the 27 strand CICC sample

  13. The ATLAS SemiConductor Tracker operation and performance

    Science.gov (United States)

    Pater, J. R.

    2012-04-01

    The ATLAS SemiConductor Tracker (SCT) is a key precision tracking detector in the ATLAS experiment at CERN's Large Hadron Collider. The SCT is composed of 4088 planar p-in-n silicon micro-strip detectors. The signals from the strips are processed in the front-end ABCD3TA ASICs, which operate in binary readout mode; data are transferred to the off-detector readout electronics via optical fibres. The SCT was completed in 2007. An extensive commissioning phase followed, during which calibration data were collected and analysed to determine the noise performance of the system, and further performance parameters of the detector were determined using cosmic ray data, both with and without magnetic field. After the commissioning phase, the SCT was ready for the first LHC proton-proton collisions in December 2009. From the beginning of data taking, the completed SCT has been in very good shape with more than 99% of its 6.3 million strips operational; the detector is well timed-in and the operational channels are 99.9% efficient in data acquisition. The noise occupancy and hit efficiency are better than the design specifications. The detector geometry is monitored continuously with a laser-based alignment system and is stable to the few-micron level; the alignment accuracy as determined by tracks is near specification and improving as statistics increase. The sensor behaviour in the 2T solenoidal magnetic field has been studied by measuring the Lorentz angle. Radiation damage in the silicon is monitored by periodic measurements of the leakage current; these measurements are in reasonable agreement with predictions.

  14. Mixed protonic-electronic conductors for hydrogen separation membranes

    Science.gov (United States)

    Song, Sun-Ju

    2003-10-01

    The chemical functionality of mixed protonic-electronic conductors arises out of the nature of the defect structure controlled by thermodynamic defect equilibria of the materials, and results in the ability to transport charged species. This dissertation is to develop a fundamental understanding of defect chemistry and transport properties of mixed protonic-electronic conducting perovskites for hydrogen separation membranes. Furthermore, it was aimed to develop the algorithm to predict how these properties affect the permeability in chemical potential gradients. From this objective, first of all, the appropriate equations governing proton incorporation into perovskite oxides were suggested and the computer simulation of defect concentrations across a membrane oxide under various conditions were performed. Electrical properties of p-type electronic defects at oxidizing conditions and n-type electrical properties of SrCe 0.95Eu0.05O3-delta at reducing atmospheres were studied. Defect equilibrium diagrams as a function of PO2 , PH2O ) produced from the Brouwer method were verified by computational simulation and electrical conductivity measurements. The chemical diffusion of hydrogen through oxide membranes was described within the framework of Wagner's chemical diffusion theory and it was solved without any simplifying assumptions on functional dependence of partial conductivity due to the successful numerical modeling of partial conductivities as a function of both hydrogen and oxygen partial pressures. Finally the hydrogen permeability of Eu and Sm doped SrCeO3-delta was studied as a function of temperature, hydrogen partial pressure gradient, and water vapor pressure gradient. The dopant dependence of hydrogen permeability was explained in terms of the difference in ionization energy and ionic radius of dopant.

  15. New design of cable-in-conduit conductor for application in future fusion reactors

    Science.gov (United States)

    Qin, Jinggang; Wu, Yu; Li, Jiangang; Liu, Fang; Dai, Chao; Shi, Yi; Liu, Huajun; Mao, Zhehua; Nijhuis, Arend; Zhou, Chao; Yagotintsev, Konstantin A.; Lubkemann, Ruben; Anvar, V. A.; Devred, Arnaud

    2017-11-01

    The China Fusion Engineering Test Reactor (CFETR) is a new tokamak device whose magnet system includes toroidal field, central solenoid (CS) and poloidal field coils. The main goal is to build a fusion engineering tokamak reactor with about 1 GW fusion power and self-sufficiency by blanket. In order to reach this high performance, the magnet field target is 15 T. However, the huge electromagnetic load caused by high field and current is a threat for conductor degradation under cycling. The conductor with a short-twist-pitch (STP) design has large stiffness, which enables a significant performance improvement in view of load and thermal cycling. But the conductor with STP design has a remarkable disadvantage: it can easily cause severe strand indentation during cabling. The indentation can reduce the strand performance, especially under high load cycling. In order to overcome this disadvantage, a new design is proposed. The main characteristic of this new design is an updated layout in the triplet. The triplet is made of two Nb3Sn strands and one soft copper strand. The twist pitch of the two Nb3Sn strands is large and cabled first. The copper strand is then wound around the two superconducting strands (CWS) with a shorter twist pitch. The following cable stages layout and twist pitches are similar to the ITER CS conductor with STP design. One short conductor sample with a similar scale to the ITER CS was manufactured and tested with the Twente Cable Press to investigate the mechanical properties, AC loss and internal inspection by destructive examination. The results are compared to the STP conductor (ITER CS and CFETR CSMC) tests. The results show that the new conductor design has similar stiffness, but much lower strand indentation than the STP design. The new design shows potential for application in future fusion reactors.

  16. Assessment of liquid hydrogen cooled MgB2 conductors for magnetically confined fusion

    International Nuclear Information System (INIS)

    Glowacki, B A; Nuttall, W J

    2008-01-01

    Importantly environmental factors are not the only policy-driver for the hydrogen economy. Over the timescale of the development of fusion energy systems, energy security issues are likely to motivate a shift towards both hydrogen production and fusion as an energy source. These technologies combine local control of the system with the collaborative research interests of the major energy users in the global economy. A concept Fusion Island Reactor that might be used to generate H 2 (rather than electricity) is presented. Exploitation of produced hydrogen as a coolant and as a fuel is proposed in conjunction with MgB 2 conductors for the tokomak magnets windings, and electrotechnical devices for Fusion Island's infrastructure. The benefits of using MgB 2 over the Nb-based conductors during construction, operation and decommissioning of the Fusion Island Reactor are presented. The comparison of Nb 3 Sn strands for ITER fusion magnet with newly developed high field composite MgB 2 PIT conductors has shown that at 14 Tesla MgB 2 possesses better properties than any of the Nb 3 Sn conductors produced. In this paper the potential of MgB 2 conductors is examined for tokamaks of both the conventional ITER type and a Spherical Tokamak geometry. In each case MgB 2 is considered as a conductor for a range of field coil applications and the potential for operation at both liquid helium and liquid hydrogen temperatures is considered. Further research plans concerning the application of MgB 2 conductors for Fusion Island are also considered

  17. Effect of non-uniform current distribution on the stability in Nb-Ti cable-in-conduit superconducting conductor

    International Nuclear Information System (INIS)

    Wadayama, Y.; Koizumi, N.; Takahashi, Y.; Matsui, K.; Tsuji, H.; Shimamoto, S.

    1996-01-01

    30kA-NbTi Demo Poloidal Coil (DPC-U) exhibited instability such as the conductor quenches at 40% of the rated current which is still much smaller than the expected conductor critical current. It was found that this instability was caused by the non-uniform current distribution in the DPC-U conductor whose strands were insulated from each other. To investigate the instability of the DPC-U conductor, a stability experiment of a subsize conductor consisting of 27 strands was performed and the effect of the current imbalance on the stability was investigated. The current imbalance was forcibly established in the conductor using two current sources in this experiment. The experimental results indicate that the stability margin decreases as the current imbalance becomes larger and that the stability margin of the conductor is governed by the stability of the strand with the highest current in the conductor. Also, it is confirmed from the experimental results that the instability of DPC-U has to be attributed to the current imbalance in the conductor

  18. Stage structure and electrical properties of rubidium-doped pentacene

    International Nuclear Information System (INIS)

    Matsuo, Yasumitsu; Sasaki, Sachio; Ikehata, Seiichiro

    2004-01-01

    We have investigated the structural and electrical properties on the molecular conductor based on pentacene doped with rubidium. It was found from the X-ray diffraction measurement that the rubidium-doped pentacene becomes a highly oriented film with a stage-1 structure, as seen in graphite intercalated compounds. It was also found from this result that the length between pentacene molecular layers increases from 1.51 nm of pure pentacene to 1.62 nm. Moreover, the result of the electrical conductivity measurement shows that by doping of rubidium electrical conductivity at room temperature increases above 10 8 times larger than that of pure pentacene. We have also found that the electrical conductivity along the a-b plane (parallel to the molecular layers) is 10 2 times larger than that along the c-axis which is perpendicular to the molecular layers. These results indicate that pentacene doped with rubidium becomes a molecular conductor and displays the quasi-two-dimensional conductivity

  19. Thermal stability analysis of YBCO-coated conductors subject to over-currents

    Energy Technology Data Exchange (ETDEWEB)

    MartInez, E; Angurel, L A; Pelegrin, J [Instituto de Ciencia de Materiales de Aragon, CSIC-Universidad de Zaragoza, C/Maria de Luna 3, E-50018 Zaragoza (Spain); Xie, Y Y; Selvamanickam, V [SuperPower Incorporated, Schenectady, NY 12304 (United States)

    2010-02-15

    The thermal stability of superconducting YBCO-coated conductors subject to over-currents are analysed. We have studied the effect of DC and AC over-current pulses in Cu-stabilized and non-stabilized coated conductors by measuring the electric field and temperature profiles of these conductors immersed in liquid nitrogen. Current pulses of short duration of about 90 ms and long duration of a few seconds were applied to the samples. Three different cooling regimes of liquid nitrogen-convection, nucleate boiling and film boiling-were observed and their influence on the recovery time of superconductivity in the coated conductors after the over-current pulses has been analysed. We have studied the recovery behaviour under two different conditions, in which the current was set to zero and to the operating current after the current pulses. These experiments simulated the conditions during an over-current situation in different electric power applications with special attention given to the behaviour of these coated conductors acting as in-fault current limiters.

  20. Thermal stability analysis of YBCO-coated conductors subject to over-currents

    International Nuclear Information System (INIS)

    MartInez, E; Angurel, L A; Pelegrin, J; Xie, Y Y; Selvamanickam, V

    2010-01-01

    The thermal stability of superconducting YBCO-coated conductors subject to over-currents are analysed. We have studied the effect of DC and AC over-current pulses in Cu-stabilized and non-stabilized coated conductors by measuring the electric field and temperature profiles of these conductors immersed in liquid nitrogen. Current pulses of short duration of about 90 ms and long duration of a few seconds were applied to the samples. Three different cooling regimes of liquid nitrogen-convection, nucleate boiling and film boiling-were observed and their influence on the recovery time of superconductivity in the coated conductors after the over-current pulses has been analysed. We have studied the recovery behaviour under two different conditions, in which the current was set to zero and to the operating current after the current pulses. These experiments simulated the conditions during an over-current situation in different electric power applications with special attention given to the behaviour of these coated conductors acting as in-fault current limiters.

  1. Keeping an eye on the conductor: neural correlates of visuo-motor synchronization and musical experience

    Science.gov (United States)

    Ono, Kentaro; Nakamura, Akinori; Maess, Burkhard

    2015-01-01

    For orchestra musicians, synchronized playing under a conductor’s direction is necessary to achieve optimal performance. Previous studies using simple auditory/visual stimuli have reported cortico-subcortical networks underlying synchronization and that training improves the accuracy of synchronization. However, it is unclear whether people who played regularly under a conductor and non-musicians activate the same networks when synchronizing with a conductor’s gestures. We conducted a functional magnetic resonance imaging (fMRI) experiment testing nonmusicians and musicians who regularly play music under a conductor. Participants were required to tap the rhythm they perceived from silent movies displaying either conductor’s gestures or a swinging metronome. Musicians performed tapping under a conductor with more precision than nonmusicians. Results from fMRI measurement showed greater activity in the anterior part of the left superior frontal gyrus (SFG) in musicians with more frequent practice under a conductor. Conversely, tapping with the metronome did not show any difference between musicians and nonmusicians, indicating that the expertize effect in tapping under the conductor does not result in a general increase in tapping performance for musicians. These results suggest that orchestra musicians have developed an advanced ability to predict conductor’s next action from the gestures. PMID:25883561

  2. Unevenness of Sliding Surface of Overhead Rigid Conductor Lines and Method for Reducing Unevenness

    Science.gov (United States)

    Aboshi, Mitsuo; Shimizu, Masashi

    Rigid conductor lines are used in many subways, because the use of such conductor lines reduces the risk of accidents and because less space is required for their installation. However, as the unevenness of the sliding surface of the rigid conductor lines significantly influences the fluctuations in the contact force between pantographs and contact lines, it is necessary to decrease the unevenness at the construction as well as the maintenance stages. In order to investigate the installation accuracy of overhead rigid conductor lines, we have developed a device that accurately and continuously measures the unevenness of the sliding surface. By using this measuring device, we have confirmed that the unevenness of the sliding surface depends on various factors such as the sag between the support points, the deformation of the aluminum base or the conductive rail in the case of a long wavelength, the slight sagging unevenness between the bolts of the long ear, the undulating wear etc. This paper describes the actual unevenness conditions and the technical methods for decreasing the unevenness of the sliding surface of overhead rigid conductor lines.

  3. Keeping an Eye on the Conductor: Neural Correlates of Visuo-motor Synchronization and Musical Experience

    Directory of Open Access Journals (Sweden)

    Kentaro eOno

    2015-04-01

    Full Text Available For orchestra musicians, synchronized playing under a conductor’s direction is necessary to achieve optimal performance. Previous studies using simple auditory/visual stimuli have reported cortico-subcortical networks underlying synchronization and that training improves the accuracy of synchronization. However, it is unclear whether people who played regularly under a conductor and non-musicians activate the same networks when synchronizing with a conductor’s gestures. We conducted a functional magnetic resonance imaging (fMRI experiment testing nonmusicians and musicians who regularly play music under a conductor. Participants were required to tap the rhythm they perceived from silent movies displaying either conductor’s gestures or a swinging metronome. Musicians performed tapping under a conductor with more precision than nonmusicians. Results from fMRI measurement showed greater activity in the anterior part of the left superior frontal gyrus (SFG in musicians with more frequent practice under a conductor. Conversely, tapping with the metronome did not show any difference between musicians and nonmusicians, indicating that the expertise effect in tapping under the conductor does not result in a general increase in tapping performance for musicians. These results suggest that orchestra musicians have developed an advanced ability to predict conductor’s next action from the gestures.

  4. The GMD Method for Inductance Calculation Applied to Conductors with Skin Effect

    Directory of Open Access Journals (Sweden)

    H. A. Aebischer

    2017-09-01

    Full Text Available The GMD method (geometric mean distance to calculate inductance offers undoubted advantages over other methods. But so far it seemed to be limited to the case where the current is uniformly distributed over the cross section of the conductor, i.e. to DC (direct current. In this paper, the definition of the GMD is extended to include cases of nonuniform distribution observed at higher frequencies as the result of skin effect. An exact relation between the GMD and the internal inductance per unit length for infinitely long conductors of circularly symmetric cross section is derived. It enables much simpler derivations of Maxwell’s analytical expressions for the GMD of circular and annular disks than were known before. Its salient application, however, is the derivation of exact expressions for the GMD of infinitely long round wires and tubular conductors with skin effect. These expressions are then used to verify the consistency of the extended definition of the GMD. Further, approximate formulae for the GMD of round wires with skin effect based on elementary functions are discussed. Total inductances calculated with the help of the derived formulae for the GMD with and without skin effect are compared to measurement results from the literature. For conductors of square cross section, an analytical approximation for the GMD with skin effect based on elementary functions is presented. It is shown that it allows to calculate the total inductance of such conductors for frequencies from DC up to 25 GHz to a precision of better than 1 %.

  5. Analysis of Lightning-induced Impulse Magnetic Fields in the Building with an Insulated Down Conductor

    Science.gov (United States)

    Du, Patrick Y.; Zhou, Qi-Bin

    This paper presents an analysis of lightning-induced magnetic fields in a building. The building of concern is protected by the lightning protection system with an insulated down conductor. In this paper a system model for metallic structure of the building is constructed first using the circuit approach. The circuit model of the insulated down conductor is discussed extensively, and explicit expressions of the circuit parameters are presented. The system model was verified experimentally in the laboratory. The modeling approach is applied to analyze the impulse magnetic fields in a full-scale building during a direct lightning strike. It is found that the impulse magnetic field is significantly high near the down conductor. The field is attenuated if the down conductor is moved to a column in the building. The field can be reduced further if the down conductor is housed in an earthed metal pipe. Recommendations for protecting critical equipment against lightning-induced magnetic fields are also provided in the paper.

  6. Activity in SRL Nagoya Coated Conductor Center for YBCO Coated Conductor by IBAD+ PLD Method -Long, high Ic conductor and a new bamboo-like nanostructure for efficient pinning

    International Nuclear Information System (INIS)

    Yamada, Yutaka; Ibi, Akira; Fukushima, Hiroyuki; Kuriki, Reiji; Takahashi, Kazuhiro; Kobayashi, Hiroyoshi; Ishida, Satoru; Konishi, Masaya; Miyata, Seiki; Watanabe, Tomonori; Kato, Takeharu; Hirayama, Tsukasa; Shiohara, Yuh

    2006-01-01

    In SRL-Nagoya Coated Conductor Center (NCCC), long buffered substrate tapes and YBCO coated conductors have been successfully fabricated by using ion-beam assisted deposition (IBAD) and pulsed laser deposition (PLD) methods. For the buffered tape, the PLD-CeO2 method, what we call the 'Self-Epitaxial' method, realized the high degree of in-plane texturing around 4 degrees along the length of 220 m. For YBCO deposition, we have recently introduced new reel-to-reel PLD equipment with a multi-plume and multi-turn deposition system (MPMT PLD). This system succeeded in fabricating a long coated conductor with a high critical current, Ic, of 245 A and length of 212 m. Ic xL (length) reached the world record of 51940 Am. Furthermore, the introduction of artificial pinning center and RE 123 materials were also studied for improving flux pinning and enhancing Ic. A new columnar structure of the 'bamboo structure' (BaZrO3/Y123 layer-stacked structure) was found in Y123+YSZ sample. This columnar structure and the stacking faults in Gd123 were found to be effective for enhancing pinning properties. Using these techniques, we have succeeded in increasing Ic at 0 T to 480 A/cm and also enhancing Ic in a magnetic field

  7. Defects and properties of cadmium oxide based transparent conductors

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Kin Man, E-mail: kinmanyu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Kowloon (Hong Kong); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Detert, D. M.; Dubon, O. D. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Chen, Guibin [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Physics Department and Jiangsu Key Laboratory for Chemistry of Low Dimensional Materials, Huaiyin Normal University, Jiangsu 223300 (China); Zhu, Wei [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Physics and The Center for Physical Experiments, University of Science and Technology of China, Hefei, Anhui 230026 (China); Liu, Chaoping [Department of Physics and Materials Science, City University of Hong Kong, Kowloon (Hong Kong); Grankowska, S. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Institute of Experimental Physics (IEP UW), Warsaw University, Warsaw (Poland); Hsu, L. [Department of Postsecondary Teaching and Learning, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Walukiewicz, Wladek [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2016-05-14

    Transparent conductors play an increasingly important role in a number of semiconductor technologies. This paper reports on the defects and properties of Cadmium Oxide, a transparent conducting oxide which can be potentially used for full spectrum photovoltaics. We carried out a systematic investigation on the effects of defects in CdO thin films undoped and intentionally doped with In and Ga under different deposition and annealing conditions. We found that at low growth temperatures (<200 °C), sputter deposition tends to trap both oxygen vacancies and compensating defects in the CdO film resulting in materials with high electron concentration of ∼2 × 10{sup 20}/cm{sup 3} and mobility in the range of 40–100 cm{sup 2}/V s. Thermal annealing experiments in different ambients revealed that the dominating defects in sputtered CdO films are oxygen vacancies. Oxygen rich CdO films grown by sputtering with increasing O{sub 2} partial pressure in the sputter gas mixture results in films with resistivity from ∼4 × 10{sup −4} to >1 Ω cm due to incorporation of excess O in the form of O-related acceptor defects, likely to be O interstitials. Intentional doping with In and Ga donors leads to an increase of both the electron concentration and the mobility. With proper doping CdO films with electron concentration of more than 10{sup 21 }cm{sup −3} and electron mobility higher than 120 cm{sup 2}/V s can be achieved. Thermal annealing of doped CdO films in N{sub 2} ambient can further improve the electrical properties by removing native acceptors and improving film crystallinity. Furthermore, the unique doping behavior and electrical properties of CdO were explored via simulations based on the amphoteric defect model. A comparison of the calculations and experimental results show that the formation energy of native donors and acceptors at the Fermi stabilization energy is ∼1 eV and that the mobility of sputtered deposited CdO is limited

  8. Defects and properties of cadmium oxide based transparent conductors

    International Nuclear Information System (INIS)

    Yu, Kin Man; Detert, D. M.; Dubon, O. D.; Chen, Guibin; Zhu, Wei; Liu, Chaoping; Grankowska, S.; Hsu, L.; Walukiewicz, Wladek

    2016-01-01

    Transparent conductors play an increasingly important role in a number of semiconductor technologies. This paper reports on the defects and properties of Cadmium Oxide, a transparent conducting oxide which can be potentially used for full spectrum photovoltaics. We carried out a systematic investigation on the effects of defects in CdO thin films undoped and intentionally doped with In and Ga under different deposition and annealing conditions. We found that at low growth temperatures (<200 °C), sputter deposition tends to trap both oxygen vacancies and compensating defects in the CdO film resulting in materials with high electron concentration of ∼2 × 10 20 /cm 3 and mobility in the range of 40–100 cm 2 /V s. Thermal annealing experiments in different ambients revealed that the dominating defects in sputtered CdO films are oxygen vacancies. Oxygen rich CdO films grown by sputtering with increasing O 2 partial pressure in the sputter gas mixture results in films with resistivity from ∼4 × 10 −4 to >1 Ω cm due to incorporation of excess O in the form of O-related acceptor defects, likely to be O interstitials. Intentional doping with In and Ga donors leads to an increase of both the electron concentration and the mobility. With proper doping CdO films with electron concentration of more than 10 21  cm −3 and electron mobility higher than 120 cm 2 /V s can be achieved. Thermal annealing of doped CdO films in N 2 ambient can further improve the electrical properties by removing native acceptors and improving film crystallinity. Furthermore, the unique doping behavior and electrical properties of CdO were explored via simulations based on the amphoteric defect model. A comparison of the calculations and experimental results show that the formation energy of native donors and acceptors at the Fermi stabilization energy is ∼1 eV and that the mobility of sputtered deposited CdO is limited by a background acceptor concentration of

  9. Theory of electromagnetic wave propagation in ferromagnetic Rashba conductor

    Science.gov (United States)

    Shibata, Junya; Takeuchi, Akihito; Kohno, Hiroshi; Tatara, Gen

    2018-02-01

    We present a comprehensive study of various electromagnetic wave propagation phenomena in a ferromagnetic bulk Rashba conductor from the perspective of quantum mechanical transport. In this system, both the space inversion and time reversal symmetries are broken, as characterized by the Rashba field α and magnetization M, respectively. First, we present a general phenomenological analysis of electromagnetic wave propagation in media with broken space inversion and time reversal symmetries based on the dielectric tensor. The dependence of the dielectric tensor on the wave vector q and M is retained to first order. Then, we calculate the microscopic electromagnetic response of the current and spin of conduction electrons subjected to α and M, based on linear response theory and the Green's function method; the results are used to study the system optical properties. First, it is found that a large α enhances the anisotropic properties of the system and enlarges the frequency range in which the electromagnetic waves have hyperbolic dispersion surfaces and exhibit unusual propagations known as negative refraction and backward waves. Second, we consider the electromagnetic cross-correlation effects (direct and inverse Edelstein effects) on the wave propagation. These effects stem from the lack of space inversion symmetry and yield q-linear off-diagonal components in the dielectric tensor. This induces a Rashba-induced birefringence, in which the polarization vector rotates around the vector (α ×q ) . In the presence of M, which breaks time reversal symmetry, there arises an anomalous Hall effect and the dielectric tensor acquires off-diagonal components linear in M. For α ∥M , these components yield the Faraday effect for the Faraday configuration q ∥M and the Cotton-Mouton effect for the Voigt configuration ( q ⊥M ). When α and M are noncollinear, M- and q-induced optical phenomena are possible, which include nonreciprocal directional dichroism in the

  10. Algorithm for detection of the broken phase conductor in the radial networks

    Directory of Open Access Journals (Sweden)

    Ostojić Mladen M.

    2016-01-01

    Full Text Available The paper presents an algorithm for a directional relay to be used for a detection of the broken phase conductor in the radial networks. The algorithm would use synchronized voltages, measured at the beginning and at the end of the line, as input signals. During the process, the measured voltages would be phase-compared. On the basis of the normalized energy, the direction of the phase conductor, with a broken point, would be detected. Software tool Matlab/Simulink package has developed a radial network model which simulates the broken phase conductor. The simulations generated required input signals by which the algorithm was tested. Development of the algorithm along with the formation of the simulation model and the test results of the proposed algorithm are presented in this paper.

  11. Stabilizing effect of passive conductors with arbitrary shape for positional instabilities

    International Nuclear Information System (INIS)

    Seki, Shogo; Ninomiya, Hiromasa; Yoshida, Hidetoshi

    1983-10-01

    For positional instabilities in the tokamak, the stabilizing index nsub(s) is an adequate parameter to characterize the stabilizing effect produced by several kinds of passive conductors around a plasma column such as vacuum vessel and poloidal field coils. Since a system of passive conductors with arbitrary shape can be involved into multiple L-R circuits, this parameter nsub(s) of those passive conductors is expressed in a simple form by using a method of the eigen mode expansion of multiple L-R circuits. This parameter nsub(s) is very useful to estimate not only a growth rate of positional instability and its feedback stabilization but also an inward shift of plasma column due to a minor disruption. (author)

  12. Progress of long coated conductors fabrication with fluorine-free CSD method at SWJTU

    International Nuclear Information System (INIS)

    Zhao, Y.; Wang, W.T.; Lei, M.; Pu, M.H.; Zhang, Y.; Cheng, C.H.

    2013-01-01

    Highlights: • Recent progress on the long coated conductors fabrication by F-free CSD method is presented. • Single buffer and partial-melting technology and slot-die coating methods have been developed. • Reel-to-reel facilities for continuous process have been achieved. -- Abstract: Recent progress on the fabrication of long high-T c superconducting coated conductors with a fluorine-free chemical solution deposition (CSD) method is presented. Developments including such novel methods as single buffer technology, partial-melting process on YBa 2 Cu 3 O 7 (YBCO), slot-die coating and drying; reel-to-reel facilities for continuous process have been achieved in the effort on high-T c superconducting coated conductors at SWJTU, which form a comprehensive technology to fabricate long coated tapes with high performances

  13. A new percolation model for composite solid electrolytes and dispersed ionic conductors

    Science.gov (United States)

    Risyad Hasyim, Muhammad; Lanagan, Michael T.

    2018-02-01

    Composite solid electrolytes (CSEs) including conductor/insulator composites known as dispersed ionic conductors (DICs) have motivated the development of novel percolation models that describe their conductivity. Despite the long history, existing models lack in one or more key areas: (1) rigorous foundation for their physical theory, (2) explanation for non-universal conductor-insulator transition, (3) classification of DICs, and (4) extension to frequency-domain. This work describes a frequency-domain effective medium approximation (EMA) of a bond percolation model for CSEs. The EMA is derived entirely from Maxwell’s equations and contains basic microstructure parameters. The model was applied successfully to several composite systems from literature. Simulations and fitting of literature data address these key areas and illustrate the interplay between space charge layer properties and bulk microstructure.

  14. Solder bond requirement for large, built-up, high-performance conductors

    International Nuclear Information System (INIS)

    Willig, R.L.

    1981-01-01

    Some large built-up conductors fabricated for large superconducting magnets are designed to operate above the maximum recovery current. Because the stability of these conductors is sensitive to the quality of the solder bond joining the composite superconductor to the high-conductivity substrate, a minimum bond requirement is necessary. The present analysis finds that the superconductor is unstable and becomes abruptly resistive when there are temperature excursions into the current sharing region of a poorly bonded conductor. This abrupt transition, produces eddy current heating in the vicinity of the superconducting filaments and causes a sharp reduction in the minimum propagating zone (MPZ) energy. This sensitivity of the MPZ energy to the solder bond contact area is used to specify a minimum bond requirement. For the superconducting MHD magnet built for the Component Development Integration Facility (CDIF), the minimum bonded surface area is .68 cm/sup 2//cm which is 44% of the composite perimeter. 5 refs

  15. Progress of long coated conductors fabrication with fluorine-free CSD method at SWJTU

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Y., E-mail: yzhao@swjtu.edu.cn [Key Lab of Advanced Materials Technologies, Key Lab of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education), Superconductivity and New Energy Center (SNEC), Southwest Jiaotong University, Chengdu 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney 2052, NSW (Australia); Wang, W.T.; Lei, M.; Pu, M.H.; Zhang, Y. [Key Lab of Advanced Materials Technologies, Key Lab of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education), Superconductivity and New Energy Center (SNEC), Southwest Jiaotong University, Chengdu 610031 (China); Cheng, C.H. [School of Materials Science and Engineering, University of New South Wales, Sydney 2052, NSW (Australia)

    2013-10-15

    Highlights: • Recent progress on the long coated conductors fabrication by F-free CSD method is presented. • Single buffer and partial-melting technology and slot-die coating methods have been developed. • Reel-to-reel facilities for continuous process have been achieved. -- Abstract: Recent progress on the fabrication of long high-T{sub c} superconducting coated conductors with a fluorine-free chemical solution deposition (CSD) method is presented. Developments including such novel methods as single buffer technology, partial-melting process on YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO), slot-die coating and drying; reel-to-reel facilities for continuous process have been achieved in the effort on high-T{sub c} superconducting coated conductors at SWJTU, which form a comprehensive technology to fabricate long coated tapes with high performances.

  16. Structural characteristics of proposed ITER [International Thermonuclear Experimental Reactor] TF [toroidal field] coil conductor

    International Nuclear Information System (INIS)

    Gibson, C.R.; Miller, J.R.

    1988-01-01

    This paper analyzes the effect of transverse loading on a cable-in-conduit conductor which has been proposed for the toroidal field coils of the International Thermonuclear Experimental Reactor. The primary components of this conductor are a loose cable of superconducting wires, a thin-wall tube for helium containment, and a U-shaped structural channel. A method is given where the geometry of this conductor can be optimized for a given set of operating conditions. It is shown, using finite-element modeling, that the structural channel is effective in supporting loads due to transverse forces and internal pressure. In addition, it is shown that the superconducting cable is effectively shielded from external transverse loads that might otherwise degrade its current carrying capacity. 10 refs., 10 figs., 3 tabs

  17. Finite-element analysis and comparison of the AC loss performance of BSCCO and YBCO conductors

    International Nuclear Information System (INIS)

    Stavrev, Svetlomir; Grilli, Francesco; Dutoit, Bertrand; Ashworth, Stephen

    2006-01-01

    The AC loss performance of two BSCCO and two YBCO conductors of different geometry, characterized by the same self-field critical current of 150 A, is analysed and compared quantitatively. The comparison is made using the finite-element method with a nonlinear B-dependent E-J relation. A new shell-region model is utilised for the simulations of thin YBCO strips. Different AC working conditions are simulated: self-field, applied external field, and combined transport current and external perpendicular field application. Magnetic field and current density profiles are investigated in order to illustrate the reasons for the loss difference in the conductors. Depending on the application, the advantages of using BSCCO or YBCO conductors with specific geometry are outlined

  18. Stray current interaction in the system of two extensive underground conductors

    International Nuclear Information System (INIS)

    Machczynski, W.

    1993-01-01

    The important problem, technically, is to evaluate the harmful effects that an electrified railway has on nearby earth-return circuits (cables, pipelines). This paper considers the effects of a DC-electrified railway system on two extensive metal conductors buried in parallel in the vicinity of the tracks. The interaction between currents flowing in both underground conductors is taken into account, whereas the reaction of the conductors' currents on the track current is disregarded. The analysis given is applicable to any DC railway system in which tracks may be represented by a single earth return circuit with current energization. It is assumed in the paper that the system considered is linear and that the earth is homogeneous. The technical application of the method is illustrated by an example of computer simulation

  19. Conductor fabrication for ITER Model Coils. Status of the EU cabling and jacketing activities

    International Nuclear Information System (INIS)

    Corte, A. della; Ricci, M.V.; Spadoni, M.; Bessette, D.; Duchateau, J.L.; Salpietro, E.; Garre, R.; Rossi, S.; Penco, R.; Laurenti, A.

    1994-01-01

    The conductors for the ITER magnets are being defined according to the operating requirements of the machine. To demonstrate the technological feasibility of the main features of the magnets, two model coils (central solenoid and toroidal field), with bores in the range 2-3 m, will be manufactured. This is the first significant industrial production of full-size conductor (a total of about 6.5 km for these coils). One cabling and one jacketing line have been assembled in Europe. The former can cable up to 1100 m (6 tons) unit lengths; the latter, which can also handle 1000 m conductor lengths, has been assembled in a shorter version (320 m). A description of the lines is reported, together with the results of the trials performed up to now. (author) 2 figs

  20. Metal{Polymer Hybrid Materials For Flexible Transparent Conductors

    Science.gov (United States)

    Narayanan, Sudarshan

    The field of organic electronics, till recently a mere research topic, is currently making rapid strides and tremendous progress into entering the mainstream electronics industry with several applications and products such as OLED televisions, curved displays, wearable devices, flexible solar cells, etc. already having been commercialized. A major component in these devices, especially for photovoltaic applications, is a transparent conductor used as one of the electrodes, which in most commercial applications are highly doped wide bandgap semiconducting oxides also called Transparent Conducting Oxides (TCOs). However, TCOs exhibit inherent disadvantages such as limited supply, brittle mechanical properties, expensive processing that present major barriers for the more widespread economic use in applications such as exible transparent conductors, owing to which suitable alternative materials are being sought. In this context we present two approaches in realizing alternative TCs using metal-polymer hybrid materials, with high figures of merit that are easily processable, reasonably inexpensive and mechanically robust as well. In this context, our first approach employs laminated metal-polymer photonic bandgap structures to effectively tune optical and electrical properties by an appropriate design of the material stack, factoring in the effect of the materials involved, the number of layers and layer properties. We have found that in the case of a four-bilayer Au/polystyrene (AujPS) laminate structure, an enhancement in optical transmittance of ˜ 500% in comparison to a monolithic A film of equivalent thickness, can be achieved. The high conductivity (˜ 106 O--1cm--1) of the metallic component, Au in this case, also ensures planar conductivity; metallic inclusions in the dielectric polymer layer can in principle give rise to out-of-plane conductivity as well enabling a fully functional TC. Such materials also have immense potential for several other applications

  1. Application of the parametric proper generalized decomposition to the frequency-dependent calculation of the impedance of an AC line with rectangular conductors

    Directory of Open Access Journals (Sweden)

    Sancarlos-González Abel

    2017-12-01

    Full Text Available AC lines of industrial busbar systems are usually built using conductors with rectangular cross sections, where each phase can have several parallel conductors to carry high currents. The current density in a rectangular conductor, under sinusoidal conditions, is not uniform. It depends on the frequency, on the conductor shape, and on the distance between conductors, due to the skin effect and to proximity effects. Contrary to circular conductors, there are not closed analytical formulas for obtaining the frequency-dependent impedance of conductors with rectangular cross-section. It is necessary to resort to numerical simulations to obtain the resistance and the inductance of the phases, one for each desired frequency and also for each distance between the phases’ conductors. On the contrary, the use of the parametric proper generalized decomposition (PGD allows to obtain the frequency-dependent impedance of an AC line for a wide range of frequencies and distances between the phases’ conductors by solving a single simulation in a 4D domain (spatial coordinates x and y, the frequency and the separation between conductors. In this way, a general “virtual chart” solution is obtained, which contains the solution for any frequency and for any separation of the conductors, and stores it in a compact separated representations form, which can be easily embedded on a more general software for the design of electrical installations. The approach presented in this work for rectangular conductors can be easily extended to conductors with an arbitrary shape.

  2. Application of the parametric proper generalized decomposition to the frequency-dependent calculation of the impedance of an AC line with rectangular conductors

    Science.gov (United States)

    Sancarlos-González, Abel; Pineda-Sanchez, Manuel; Puche-Panadero, Ruben; Sapena-Bano, Angel; Riera-Guasp, Martin; Martinez-Roman, Javier; Perez-Cruz, Juan; Roger-Folch, Jose

    2017-12-01

    AC lines of industrial busbar systems are usually built using conductors with rectangular cross sections, where each phase can have several parallel conductors to carry high currents. The current density in a rectangular conductor, under sinusoidal conditions, is not uniform. It depends on the frequency, on the conductor shape, and on the distance between conductors, due to the skin effect and to proximity effects. Contrary to circular conductors, there are not closed analytical formulas for obtaining the frequency-dependent impedance of conductors with rectangular cross-section. It is necessary to resort to numerical simulations to obtain the resistance and the inductance of the phases, one for each desired frequency and also for each distance between the phases' conductors. On the contrary, the use of the parametric proper generalized decomposition (PGD) allows to obtain the frequency-dependent impedance of an AC line for a wide range of frequencies and distances between the phases' conductors by solving a single simulation in a 4D domain (spatial coordinates x and y, the frequency and the separation between conductors). In this way, a general "virtual chart" solution is obtained, which contains the solution for any frequency and for any separation of the conductors, and stores it in a compact separated representations form, which can be easily embedded on a more general software for the design of electrical installations. The approach presented in this work for rectangular conductors can be easily extended to conductors with an arbitrary shape.

  3. Analysis of hazardous work environment factors at a train conductor workplace

    Directory of Open Access Journals (Sweden)

    M.F. Vil'k

    2017-12-01

    Full Text Available The paper dwells on generalized analysis of morbidity which is characteristic for conductors working in passenger carriages of locomotive-driven trains. Working conditions train conductors had to work in were examined as per results of sanitary-hygienic research on intra-carriage environment, specific working conditions assessment, and questioning. Hazards caused by working environment factors for train conductors to a certain extent depend on a carriage type, its technical and hygienic state, as well as on a route a train goes by. Our research revealed that impacts exerted by various working environment factors, namely physical, chemical, biological, and psychophysical ones, caused respiratory diseases, increased allergic reactivity, changes in hearing sensitivity, and overall morbidity growth among people from this occupational group. Unordered regime resulting from constant trips and unfavorable living conditions in a carriage lead to the following diseases: varix dilatation in legs, ischemic heart disease together with primary hypertension, and chronic rheumatic heart diseases. More precise classification of conductors' working conditions can be obtained via a mathematical model creation as it enables precise estimation of occupational diseases probability. Such models should be based on a relationship between diseases frequency (or probability and working conditions as per specific hygienic factors. We worked out methodical guidelines on providing safe working conditions at conductors' working places which include efficient activities aimed at prevention of hazardous impacts exerted by working environment factors. It will help to improve working conditions substantially, to preserve workers' health, and to ensure safe passengers traffic. Safe working conditions for conductors can be secured due to a set of activities aimed at equipping new carriages and those after capital repair with air-conditioning, disinfection systems, heating

  4. Analysis of Conductor Impedances Accounting for Skin Effect and Nonlinear Permeability

    Energy Technology Data Exchange (ETDEWEB)

    Perkins, M P; Ong, M M; Brown, C G; Speer, R D

    2011-07-20

    It is often necessary to protect sensitive electrical equipment from pulsed electric and magnetic fields. To accomplish this electromagnetic shielding structures similar to Faraday Cages are often implemented. If the equipment is inside a facility that has been reinforced with rebar, the rebar can be used as part of a lighting protection system. Unfortunately, such shields are not perfect and allow electromagnetic fields to be created inside due to discontinuities in the structure, penetrations, and finite conductivity of the shield. In order to perform an analysis of such a structure it is important to first determine the effect of the finite impedance of the conductors used in the shield. In this paper we will discuss the impedances of different cylindrical conductors in the time domain. For a time varying pulse the currents created in the conductor will have different spectral components, which will affect the current density due to skin effects. Many construction materials use iron and different types of steels that have a nonlinear permeability. The nonlinear material can have an effect on the impedance of the conductor depending on the B-H curve. Although closed form solutions exist for the impedances of cylindrical conductors made of linear materials, computational techniques are needed for nonlinear materials. Simulations of such impedances are often technically challenging due to the need for a computational mesh to be able to resolve the skin depths for the different spectral components in the pulse. The results of such simulations in the time domain will be shown and used to determine the impedances of cylindrical conductors for lightning current pulses that have low frequency content.

  5. TOPICAL REVIEW: Development of high-current high-field conductors in Europe for fusion application

    Science.gov (United States)

    Duchateau, J.-L.; Spadoni, M.; Salpietro, E.; Ciazynski, D.; Ricci, M.; Libeyre, P.; della Corte, A.

    2002-06-01

    In the framework of the preparation for the realization of the international thermonuclear experimental reactor (ITER), the construction and test of relevant models of seven different parts of the reactor was decided. Two of them are related to the superconducting coils: the toroidal field model coil (TFMC) and the central solenoid model coil (CSMC). For these superconducting coils, due to the expected high values of the current (≥60 kA) and voltage (≥5 kV with respect to the ground) the adopted technology was that of cable in conduit conductor (CICC). Until recently, little experience of this technology existed. Therefore, an extensive research and development programme has been carried out, in the last 10 years, by the ITER partners and particularly in Europe, to design, industrialize and test these large conductors and their joints. The EURATOM associations CEA and ENEA played a leading part in this phase. The CICC concept is described and the results of the developments are presented. About 7 km of conductors were manufactured in the industry and for that more than 10 tonnes of Nb3Sn strands were produced in Europe. In this large programme, Europe is particularly in charge of the TFMC, which will be tested this summer at Forschung Zentrum Karlsruhe (Germany). In the framework of this programme, three full size conductors and joint samples were tested at the European Sultan test facility (Centre de Recherches de Physique des Plasmas, Villigen, Switzerland), to validate the technological choices and check that the ITER specifications were met. The results of these tests are presented in detail. Starting from the strand critical properties, the conductors made of about 1000 strands did reach their expected performance. The joints of these large conductors are very special and delicate components. Their behaviour was quite successful and the joint resistance of these samples (of the order of 1 nΩ) was well within the specifications.

  6. Effect of conductor geometry on source localization: Implications for epilepsy studies

    International Nuclear Information System (INIS)

    Schlitt, H.; Heller, L.; Best, E.; Ranken, D.; Aaron, R.

    1994-01-01

    We shall discuss the effects of conductor geometry on source localization for applications in epilepsy studies. The most popular conductor model for clinical MEG studies is a homogeneous sphere. However, several studies have indicated that a sphere is a poor model for the head when the sources are deep, as is the case for epileptic foci in the mesial temporal lobe. We believe that replacing the spherical model with a more realistic one in the inverse fitting procedure will improve the accuracy of localizing epileptic sources. In order to include a realistic head model in the inverse problem, we must first solve the forward problem for the realistic conductor geometry. We create a conductor geometry model from MR images, and then solve the forward problem via a boundary integral equation for the electric potential due to a specified primary source. One the electric potential is known, the magnetic field can be calculated directly. The most time-intensive part of the problem is generating the conductor model; fortunately, this needs to be done only once for each patient. It takes little time to change the primary current and calculate a new magnetic field for use in the inverse fitting procedure. We present the results of a series of computer simulations in which we investigate the localization accuracy due to replacing the spherical model with the realistic head model in the inverse fitting procedure. The data to be fit consist of a computer generated magnetic field due to a known current dipole in a realistic head model, with added noise. We compare the localization errors when this field is fit using a spherical model to the fit using a realistic head model. Using a spherical model is comparable to what is usually done when localizing epileptic sources in humans, where the conductor model used in the inverse fitting procedure does not correspond to the actual head

  7. Tension optimization of the conductor-and-support cable elements during stranding process

    Directory of Open Access Journals (Sweden)

    I.M. Chayun

    2016-12-01

    Full Text Available Steel lifting ropes, cables and other similar products are rod statically undeterminable prestressed structures. Preliminary deformations of their elements (wires are caused by their manufacturing technology. Wires suffer stretching, bending with torsion in a stage of elastoplastic deformation. In this work the mechanic-mathematical model of residual forces determination in the wires of polymetallic conductor-and-support cable is offered. Aim: The aim of the work is studying of the mechanical and mathematical model defining residual forces in the wires of conductor-and-support cable and also the optimization of parameters of a twist by the criterion of residual forces lack after production process finishing. Materials and methods: The method developed by the authors earlier to the study the strain-stressed state of twisted wire products off-loading from technological internal forces has been applied to assess the impact of the approximate value of the longitudinal stiffness of the product. In this paper, each wire is considered as an element of the product individually. This is necessary to investigate the impact of uneven wire tensions on defects of conductor-and-support cable (out-of-straight in a free state and stripping-down. Results: On the basis of the conducted deformation studies of conductor-and-support cable during off-loading process from twist tension of its elements the dependencies of residual forces on the level and interrelation of elements tension has been determined. The condition of ensuring of zero residual forces in the wires of conductor-and-support cable after production is formulated. It was found that calculated values of residual forces are almost identical when using of the approximate and exact values of longitudinal stiffness of conductor-and-support cable.

  8. AC losses for the various voltage-leads in a semi-triple layer BSCCO conductor

    International Nuclear Information System (INIS)

    Li, Z.; Ryu, K.; Hwang, S.D.; Cha, G.; Song, H.J.

    2011-01-01

    Two voltage-leads (inner-lead, outer-lead) were soldered to the wires in each layer. Voltage-lead (total-lead) was soldered to the inner layer and arranged on the surface of the outer layer. The loss from the total-lead significantly differs from the sum of the wire losses. In order to investigate the AC loss of the multilayer conductor in a high temperature superconductor cable, a voltage-lead was generally attached to the outermost layer of the conductor. But the conductor's AC loss has not been completely cleared due to the various contact positions and arrangements of the voltage-lead. In this paper, we prepared a semi-triple layer conductor consisting of an inner layer and an outer layer with double layer structure. To measure the AC loss of the conductor, two voltage-leads (inner-lead, outer-lead) were soldered to the wires in each layer and arranged along their surfaces, as well as another voltage-lead (total-lead) was soldered to the inner layer and arranged on the surface of the outer layer. The results show that the AC losses for each layer measured from the inner-lead and the outer-lead, respectively, are identical to the sum of the wire losses. The AC losses in the semi-triple layer conductor measured from the total-lead and the outer-lead are identical for the uniform layer current density, and similar to the sum of the wire losses in both layers. However, the losses measured for the non-uniform layer current density from three voltage-leads are unequal to each other, and the loss from the total-lead significantly differs from the sum of the wire losses.

  9. Methods to reduce AC losses in HTS coated conductors with magnetic substrates

    Energy Technology Data Exchange (ETDEWEB)

    Tsukamoto, O. [Faculty of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan)], E-mail: osami-t@ynu.ac.jp; Sekizawa, S.; Alamgir, A.K.M. [Faculty of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan); Miyagi, D. [Okayama University, 1-1, Tsushima-Naka, 1-Chome, Okayama 700-8530 (Japan)

    2007-10-01

    HTS coated conductors (CCs) have high potentials as low-cost and long length conductors. However, a question remains as to what influence the magnetic property of the substrates has on the AC losses. In this paper, the influence of magnetic property of substrates on the AC losses in HTS CCs is studied. Based on the study methods to reduce the AC transport current losses and magnetization losses in CCs with magnetic substrates are investigated. It is shown that the losses can be reduced to the same level of those in CCs with non-magnetic substrates.

  10. Methods to reduce AC losses in HTS coated conductors with magnetic substrates

    International Nuclear Information System (INIS)

    Tsukamoto, O.; Sekizawa, S.; Alamgir, A.K.M.; Miyagi, D.

    2007-01-01

    HTS coated conductors (CCs) have high potentials as low-cost and long length conductors. However, a question remains as to what influence the magnetic property of the substrates has on the AC losses. In this paper, the influence of magnetic property of substrates on the AC losses in HTS CCs is studied. Based on the study methods to reduce the AC transport current losses and magnetization losses in CCs with magnetic substrates are investigated. It is shown that the losses can be reduced to the same level of those in CCs with non-magnetic substrates

  11. The CMS Magnet Commissioning and the Development of an Improved CMS Conductor Suitable for Future Proposals

    CERN Document Server

    Campi, D; Gaddi, A; Gerwig, H; Hervé, A; Sgobba, S; Fabbricatore, P; Kircher, F

    2008-01-01

    The success of the CMS Magnet commissioning has clearly shown the reliability of the conceptual choices for the cold mass. The reinforced conductor and the multi layer winding open the path for the conception of Large Magnet for HEP of the next generation. The paper will report about the basic results of the test campaign and then, after some critical considerations about the choices made for the CMS coil construction, possible improvements for the conductor construction are outlined. The main goal being to preserve long term RRR, and thus stability, of the insert and simplify the welding process to join the reinforcement alloy to the insert.

  12. Raman Spectroscopic Studies of YBa2Cu3O7 Coated Conductors

    International Nuclear Information System (INIS)

    Choi, Mi Kyeung; Mnh, Nguyen Van; Bae, J. S.; Jo, William; Yang, In Sang; Ko, Rock Kil; Ha, Hong Soo; Park, Chan

    2005-01-01

    We present results of Raman spectroscopic studies of superconducting YBa 2 Cu 3 O 7 (YBCO) coated conductors. Raman scattering is used to characterize optical phonon modes, oxygen content, c-axis misalignment, and second phases of the YBCO coated conductors at a micro scale. A two-dimensional mapping of Raman spectra with transport properties has been performed to elucidate the effect of local propertied on current path and superconducting phase. The information taken from the local measurement will be useful for optimizing the process condition.

  13. Prácticas de Física: Resistividad de un conductor y ley de Ohm

    OpenAIRE

    Beléndez, Augusto; Bernabeu, Guillermo; Vera Guarinos, Jenaro; Pastor Antón, Carlos; Martín García, Agapito

    1988-01-01

    El objetivo de esta práctica de laboratorio es la determinación de la resistividad de un conductor mediante la utilización de la ley de Ohm. Como conductor se utiliza hilo constantán del cual se mide su longitud con una cinta métrica y su diámetro con un palmer. Con estos valores y con los de la resistencia del hilo determinada a partir de un ajuste por mínimos cuadrados de los voltajes aplicados y las intensidades que circulan por el hilo, se determina el valor de la resistividad.

  14. Inducted circulation current in a conductor consisting of strands coated with a high resistive layer

    International Nuclear Information System (INIS)

    Koizumi, Norikiyo; Takahashi, Yoshikazu; Kato, Takashi; Tsuji, Hiroshi; Shimamoto, Susumu

    2000-01-01

    Nonuniform current distribution is generated in a conductor consisting of strands coated by a high resistive layer, such as chromium plating, as a result of superimposition of transport and induce circulation currents. The characteristics of the induced circulation current are analytically studied by using a distributed model circuit. The parameters mostly used in this calculation are those of US-DPC coil, which at first exhibited instability and so-called ramp rate limitation (RRL) because of current imbalance in the conductor consisting of chrome-plated strands. Thus the conductance along strands and the inductance of unit length loop and length of the conductor are mostly assumed to be 10 kS/m, 0.5 μH/m and 150 m, respectively. The analysis results indicate that the induced circulation current can be classified into the boundary and interstrand-induce circulation currents hereafter referred to as BICC an IICC. BICC is induced only across the joint at the ends of the conductor, resulting in a constant along the conductor axis, when the total leakage magnetic flux of the loop is not zero. Its decay time constant is quite long, more than a few hours. In contrast, when the leakage magnetic flux distributes along the conductor axis, IICC is induced among strands in the conductor to eliminate this flux. Since the leakage magnetic flux normally becomes largest where the magnetic field is highest, it becomes larger where the time variation of the magnetic field is larger. Its decay time contrast is much less than that of BICC. If the leakage magnetic flux linearly changes along the US-DPC conductor, it is evaluated to be about 10 s. This IICC therefore becomes dominate in a pulse charge, whose ramping tine is less than 10 s. Moreover, it is found that the variation of the leakage a magnetic flux with the relatively long cycle, such as more than a few 10-meter lengths, causes IICC with a decay-time constant of more than several hundred milliseconds. Such and IICC can

  15. On propagation of sound waves in Q2D conductors in a quantizing magnetic field

    CERN Document Server

    Kirichenko, O V; Galbova, O; Ivanovski, G; Krstovska, D

    2003-01-01

    The attenuation of sound waves propagating normally to the layers of a Q2D conductor is analysed at low enough temperatures when quantization of the energy of conduction electrons results in an oscillatory dependence of the sound attenuation rate on the inverse magnetic field. The sound wave decrement is found for different orientations of the magnetic field with respect to the layers. A layered conductor is shown to be most transparent in the case when the magnetic field is orthogonal to the layers.

  16. A corrugated perfect magnetic conductor surface supporting spoof surface magnon polaritons.

    Science.gov (United States)

    Liu, Liang-liang; Li, Zhuo; Gu, Chang-qing; Ning, Ping-ping; Xu, Bing-zheng; Niu, Zhen-yi; Zhao, Yong-jiu

    2014-05-05

    In this paper, we demonstrate that spoof surface magnon polaritons (SSMPs) can propagate along a corrugated perfect magnetic conductor (PMC) surface. From duality theorem, the existence of surface electromagnetic modes on corrugated PMC surfaces are manifest to be transverse electric (TE) mode compared with the transverse magnetic (TM) mode of spoof surface plasmon plaritons (SSPPs) excited on corrugated perfect electric conductor surfaces. Theoretical deduction through modal expansion method and simulation results clearly verify that SSMPs share the same dispersion relationship with the SSPPs. It is worth noting that this metamaterial will have more similar properties and potential applications as the SSPPs in large number of areas.

  17. Spectroscopy of charge transfer complexes of four amino acids as organic two-dimensional conductors

    International Nuclear Information System (INIS)

    Padhiyar, Ashvin; Patel, A J; Oza, A T

    2007-01-01

    It is found in this study that four amino acids, namely asparagine, arginine, histidine and glutamine form two-dimensional conducting systems which are charge transfer complexes (CTCs) with organic acceptors like TCNQ, TCNE, chloranil, DDQ, TNF and iodine. It is verified using optical absorption edges that these are 2d conductors like transition metal dichalcogenides obeying absorption functions different from 1d and 3d conductors. This 2d nature is related to the network of intermolecular H-bonding in these complexes, which leads to a global H-bonded network resulting in the absence of local deformation due to the relaxation of strain

  18. On propagation of sound waves in Q2D conductors in a quantizing magnetic field

    International Nuclear Information System (INIS)

    Kirichenko, O.V.; Peschansky, V.G.; Galbova, O.; Ivanovski, G.; Krstovska, D.

    2003-01-01

    The attenuation of sound waves propagating normally to the layers of a Q2D conductor is analysed at low enough temperatures when quantization of the energy of conduction electrons results in an oscillatory dependence of the sound attenuation rate on the inverse magnetic field. The sound wave decrement is found for different orientations of the magnetic field with respect to the layers. A layered conductor is shown to be most transparent in the case when the magnetic field is orthogonal to the layers

  19. Use of moving heat conductor mesh to perform reflood calculations with RELAP4/MOD6

    International Nuclear Information System (INIS)

    Fischer, S.R.; Ellis, L.V.; Chen, Y.S.

    1979-01-01

    RELAP4 is a computer code which can be used for the transient thermal hydraulic analysis of light water reactors and related systems. RELAP4/MOD6 includes many new analytical models which were developed primarily for the analysis of the reflood phase of a PWR loss-of-coolant accident (LOCA) transient. The key feature forming the basis for the MOD6 reflood calculation is a unique moving finite differenced heat conductor. The development and application of the moving heat conductor mesh for use in reflood analysis are described

  20. The future of high-strength copper base conductor materials; Hochfeste Leitermaterialien auf Kupfer-Basis: quo vadis?

    Energy Technology Data Exchange (ETDEWEB)

    Freudenberger, J.; Botcharova, E.; Gaganov, A.; Lyubimova, J.; Schultz, L. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany). Inst. fuer Metallische Werkstoffe; Witte, H.; Jones, H. [Oxford Univ. (United Kingdom). Dept. of Physics; Hermannsdoerfer, T.; Zherlitsyn, S.; Wosnitza, J. [Forschungszentrum Rossendorf e.V. (FZR), Dresden (Germany). Hochfeld-Magnetlabor; Givord, D. [Institut Neel, Grenoble (France); Barthem, V.M.T.S. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Fisica; Boettcher, R.D.; Hannemann, K. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Goettingen (Germany). Inst. fuer Aerodynamik und Stroemungstechnik

    2008-07-01

    Conductor materials with specific mechanical properties are required in many fields of science and industry. They are optimised selectively to achieve certain properties and optimum functionality, which often makes them a key component of the system in which they are used. This contribution describes current and future applications of the copper base high-strength conductor materials developed at IFW Dresden. (orig.)

  1. Measurement of local critical currents in TFA-MOD processed coated conductors by use of scanning Hall-probe microscopy

    International Nuclear Information System (INIS)

    Shiohara, K.; Higashikawa, K.; Kawaguchi, T.; Inoue, M.; Kiss, T.; Yoshizumi, M.; Izumi, T.

    2011-01-01

    We have investigated 2-dimensional distribution of critical current density. We have measured TFA-MOD processed YBCO coated conductor. We used scanning Hall-probe microscopy. These provided information is useful for fabrication process of coated conductor. We have carried out 2-dimensional (2D) measurement of local critical current in a Trifluoroacetates-Metal Organic Deposition (TFA-MOD) processed YBCO coated conductor using scanning Hall-probe microscopy. Recently, remarkable R and D accomplishments on the fabrication processes of coated conductors have been conducted extensively and reported. The TFA-MOD process has been expected as an attractive process to produce coated conductors with high performance at a low production cost due to a simple process using non-vacuum equipments. On the other hand, enhancement of critical currents and homogenization of the critical current distribution in the coated conductors are definitely very important for practical applications. According to our measurements, we can detect positions and spatial distribution of defects in the conductor. This kind of information will be very helpful for the improvement of the TFA-MOD process and for the design of the conductor intended for practical electric power device applications.

  2. On the stability conditions of flexible current conductor tightened in a magnetic field for charged particle trajectory tracing

    International Nuclear Information System (INIS)

    Kozodaev, M.S.

    1974-01-01

    Conditions of equilibrium stability in three-dimensional space for a stretched flexible current conductor, while tracing the trajectories of charged particles moving in a magnetic field, have been determined using variational principles. Formulas suitable for engineering calculations have been obtained that allow to determine the stability regions and to estimate errors in tracing due to the conductor weight and elasticity

  3. Signal processing of data from short sample tests for the projection of conductor performance in ITER magnets

    International Nuclear Information System (INIS)

    Martovetsky, Nicolai

    2008-01-01

    Qualification of the ITER conductor is absolutely necessary. Testing large scale conductors is expensive and time-consuming. To test 3-4 m long straight samples in a bore of a split solenoid is a relatively economical way in comparison with the fabrication of a coil to be tested in a bore of a background field solenoid. However, testing short samples may give ambiguous results due to different constraints in current redistribution in the cable or other end effects which are not present in the large magnet. This paper discusses the processes taking place in the ITER conductor, conditions when conductor performance could be distorted and possible signal processing to deduce the behaviour of ITER conductors in ITER magnets from the test data

  4. Critical current and cryogenic stability modelling of filamentary MgB2 conductors

    DEFF Research Database (Denmark)

    Glowacki, B.A.; Majoros, M.; Tanaka, K.

    2006-01-01

    The modelling of a single filament, 6 filaments and 19 filaments MgB(2) conductors was performed for two limiting cases: a) isothermal conditions considering J(c)(B) dependence, b) considering heating effects but with J(c) magnetic field independent. As a starting point of the modelling in case a...

  5. Characterization and properties of an advanced composite substrate for YBCO-coated conductors

    DEFF Research Database (Denmark)

    Gao, M.; Suo, H.; Zhao, Y.

    2010-01-01

    Thin, biaxially textured Ni5W/Ni12W/Ni5W composite substrates for coated conductor applications have been fabricated. The particularity of this three-layer composite configuration resides in the elemental diffusion between the outer layer and the core layer. Due to the migration of elemental W...

  6. Mixed ionic-electronic conductor-based radiation detectors and methods of fabrication

    Science.gov (United States)

    Conway, Adam; Beck, Patrick R; Graff, Robert T; Nelson, Art; Nikolic, Rebecca J; Payne, Stephen A; Voss, Lars; Kim, Hadong

    2015-04-07

    A method of fabricating a mixed ionic-electronic conductor (e.g. TlBr)-based radiation detector having halide-treated surfaces and associated methods of fabrication, which controls polarization of the mixed ionic-electronic MIEC material to improve stability and operational lifetime.

  7. Quantitative computed tomography for objectifying disseminated skeletal muscles alterations in female conductors of progressive muscular dystrophy

    International Nuclear Information System (INIS)

    Huppert, P.

    1987-01-01

    The detection of early morphologic changes, such as circumscribed infiltrations of adipose connective tissue into the muscles of female conductors of progressive muscular dystrophy requires quantitative planimetric methods. For a reliable interpretation of the results the dependence of the fat content of the musculature on age and physical constitution of the patient must be taken into consideration in each individual case. (author)

  8. Proton conductivity of phosphoric acid doped polybenzimidazole and its composites with inorganic proton conductors

    DEFF Research Database (Denmark)

    He, Ronghuan; Qingfeng, Li; Gang, Xiao

    2003-01-01

    Phosphoric acid doped polybenzimidazole (PBI) and PBI composite membranes have been prepared in the present work. The PBI composites contain inorganic proton conductors including zirconium phosphate (ZrP), (Zr(HPO4)2·nH2O), phosphotungstic acid (PWA), (H3PW12O40·nH2O) and silicotungstic acid (Si...

  9. Design study of coated conductor direct drive wind turbine generator for small scale demonstration

    DEFF Research Database (Denmark)

    Abrahamsen, Asger Bech; Jensen, Bogi Bech

    2012-01-01

    We have investigated the properties of a superconducting direct drive generator suitable for demonstration in a small scale 11 kW wind turbine. The engineering current density of the superconducting field windings is based on properties of coated conductors wound into coils holding of the order 68...

  10. The generation of charge carriers in semi conductors – A theoretical study

    CSIR Research Space (South Africa)

    Kiarii, EM

    2017-04-01

    Full Text Available , vol. 678: 167-176 The generation of charge carriers in semi conductors – A theoretical study Kiarii EM Govender, Krishna K Ndungu PG Govender PG ABSTRACT: A systematic study of electronic and optical properties of titanium dioxide under...

  11. On the Behaviour of Current-Carrying Wire-Conductors and Bucking of a Column

    DEFF Research Database (Denmark)

    Ganji, S. S.; Barari, Amin; Fereidoon, A.

    2013-01-01

    This paper applies approximate analytical methods namely Iteration Perturbation Method (IPM), variational approach (VA) and Parameter Expanding Method (PEM) to Single-Degree-Of-Freedom (SDOF) nonlinear oscillation systems. Some numerical cases as dynamic behavior of current-carrying wire-conductors...

  12. Short-circuit experiments on a high Tc-superconducting cable conductor

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Jensen, E.H.; Traholt, C.

    2002-01-01

    A high temperature superconductor (HTS) cable conductor (CC) with a critical current of 2.1 kA was tested over a range of short-circuit currents up to 20 kA. The duration of the short-circuit currents is 1 s. Between each short-circuit test the critical current of the HTS CC was measured in order...

  13. Neutron Scattering Studies of the Ionic Conductor LiI D2O

    DEFF Research Database (Denmark)

    Andersen, N. H.; Kjems, Jørgen; Poulsen, Finn Willy

    1982-01-01

    The structural properties of the ionic conductor LiID2O have been studied by neutron scattering. The cubic room temperature α-phase, Pm3m, is disordered both with respect to the occupation of the Li+-positions and to the orientations of the water molecules. A first order phase transition from the α...

  14. Circular Array of Magnetic Sensors for Current Measurement: Analysis for Error Caused by Position of Conductor.

    Science.gov (United States)

    Yu, Hao; Qian, Zheng; Liu, Huayi; Qu, Jiaqi

    2018-02-14

    This paper analyzes the measurement error, caused by the position of the current-carrying conductor, of a circular array of magnetic sensors for current measurement. The circular array of magnetic sensors is an effective approach for AC or DC non-contact measurement, as it is low-cost, light-weight, has a large linear range, wide bandwidth, and low noise. Especially, it has been claimed that such structure has excellent reduction ability for errors caused by the position of the current-carrying conductor, crosstalk current interference, shape of the conduction cross-section, and the Earth's magnetic field. However, the positions of the current-carrying conductor-including un-centeredness and un-perpendicularity-have not been analyzed in detail until now. In this paper, for the purpose of having minimum measurement error, a theoretical analysis has been proposed based on vector inner and exterior product. In the presented mathematical model of relative error, the un-center offset distance, the un-perpendicular angle, the radius of the circle, and the number of magnetic sensors are expressed in one equation. The comparison of the relative error caused by the position of the current-carrying conductor between four and eight sensors is conducted. Tunnel magnetoresistance (TMR) sensors are used in the experimental prototype to verify the mathematical model. The analysis results can be the reference to design the details of the circular array of magnetic sensors for current measurement in practical situations.

  15. High-performance rechargeable batteries with fast solid-state ion conductors

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, Joseph C.

    2017-06-27

    A high-performance rechargeable battery using ultra-fast ion conductors. In one embodiment the rechargeable battery apparatus includes an enclosure, a first electrode operatively connected to the enclosure, a second electrode operatively connected to the enclosure, a nanomaterial in the enclosure, and a heat transfer unit.

  16. The current distribution in Bi-2223/Ag HTS conductors: comparing Hall probe and magnetic knife

    NARCIS (Netherlands)

    Demencik, E.; Dhalle, Marc M.J.; ten Kate, Herman H.J.; Polak, M.

    2006-01-01

    We analyzed the current distribution in three Bi-2223/Ag tapes with different filament lay-out, comparing the results of magnetic knife and Hall probe experiments. Detailed knowledge of the current distribution can be useful for the diagnostics of HTS conductors. The lateral current distribution was

  17. Progress in R and D of coated conductor in M-PACC project

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, T.; Koizumi, T.; Kimura, K. [SWCC Showa Cable Systems Co., Ltd., Kanagawa (Japan); Kato, T. [Japan Fine Ceramics Center, Aichi (Japan); Kiss, T. [Kyushu University, Fukuoka (Japan); Izumi, T.; Ibi, A.; Nakaoka, K. [Superconductivity Research Laboratory, International Superconductivity Technology, Kanagawa (Japan); and others

    2014-06-15

    The five-year national project in Japan for R and D of coated conductors and applications, named as the Materials and Power Applications of Coated Conductors (M-PACC) project, was finished at the end of FY2013. The project consists of four sub-themes as cable, transformer, SMES and coated conductors. In the theme of coated conductors, the fabrication process had been developed to satisfy the requirements from the applications such as in-field I{sub c} performance, low AC loss in the long tapes etc. Through the project, the remarkable progress was achieved as follows; a high in-field minimum I-c value over 54A/cm-width under 3T at 77K was realized in a 200m long EuBCO tape with artificial pinning centers of BaHfO{sub 3} by the pulsed laser deposition (PLD) technique on the IBAD template. On the other hand, the AC loss reduction was confirmed in the tapes fabricated by both PLD and the metal organic deposition (MOD) techniques by scribing 100 m tapes into 10-filaments. Additionally, the mechanism of the delamination phenomenon was systematically investigated and the strength was improved by eliminating the origins of the weak points in the films. Through the development, all targeted goals were accomplished and the several results were appreciated as a world champion data.

  18. Peierls instability and superconductivity in substitutionally disordered pseudo one-dimensional conductors

    International Nuclear Information System (INIS)

    Zhang, L.

    1981-08-01

    With coherent potential approximation method the effect of the substitutional disorder in the pseudo one-dimensional conductors on the Peierls transition temperature (Tsub(p)) and superconductive transition temperature (Tsub(c)) has been calculated. The favourable condition for searching for somewhat high Tsub(c) superconductors in these systems has been discussed. (author)

  19. 30 CFR 56.12005 - Protection of power conductors from mobile equipment.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Protection of power conductors from mobile equipment. 56.12005 Section 56.12005 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL...

  20. 30 CFR 57.12005 - Protection of power conductors from mobile equipment.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Protection of power conductors from mobile equipment. 57.12005 Section 57.12005 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND...

  1. 30 CFR 56.12069 - Lightning protection for telephone wires and ungrounded conductors.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Lightning protection for telephone wires and... NONMETAL MINES Electricity § 56.12069 Lightning protection for telephone wires and ungrounded conductors... lightning shall be equipped with suitable lightning arrestors of approved type within 100 feet of the point...

  2. 30 CFR 75.521 - Lightning arresters; ungrounded and exposed power conductors and telephone wires.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Lightning arresters; ungrounded and exposed... Electrical Equipment-General § 75.521 Lightning arresters; ungrounded and exposed power conductors and... leads underground shall be equipped with suitable lightning arresters of approved type within 100 feet...

  3. 30 CFR 77.508 - Lightning arresters, ungrounded and exposed power conductors and telephone wires.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Lightning arresters, ungrounded and exposed... AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Electrical Equipment-General § 77.508 Lightning... conductors and telephone wires shall be equipped with suitable lightning arresters which are adequately...

  4. Fabrication of the Textured Ni-9.3at.%W Alloy Substrate for Coated Conductors

    DEFF Research Database (Denmark)

    Gao, M. M.; Suo, H. L.; Grivel, Jean-Claude

    2011-01-01

    It is difficult to obtain a sharp cube texture in the Ni-9.3at.% W substrate used for coated conductors due to its low stacking fault energy. In this paper, the traditional cold rolling procedure was optimized by introducing an intermediate recovery annealing. The deformation texture has been imp...

  5. EMF measurements on mixed protonic/electronic conductors for hydrogen membrane applications

    DEFF Research Database (Denmark)

    Bentzer, Henrik Karnøe; Bonanos, Nikolaos; Phair, John

    2010-01-01

    Electromotive force (EMF) measurements are often used to estimate the transport number of conducting species in ionic and mixed conductors. In this work, the applicability of the method to systems, where both protonic, oxide-ionic and electronic conduction is significant, was examined. The effect...

  6. A Classroom Activity for Teaching Electric Polarization of Insulators and Conductors

    Science.gov (United States)

    Deligkaris, Christos

    2018-01-01

    The phenomenon of electric polarization is crucial to student understanding of forces exerted between charged objects and insulators or conductors, the process of charging by induction, and the behavior of electroscopes near charged objects. In addition, polarization allows for microscopic-level models of everyday-life macroscopic-level phenomena.…

  7. Printable elastic conductors by in situ formation of silver nanoparticles from silver flakes

    NARCIS (Netherlands)

    Matsuhisa, N.; Inoue, D.; Zalar, P.; Jin, H.; Matsuba, Y.; Itoh, A.; Yokota, T.; Hashizume, D.; Someya, T.

    2017-01-01

    Printable elastic conductors promise large-area stretchable sensor/actuator networks for healthcare, wearables and robotics. Elastomers with metal nanoparticles are one of the best approaches to achieve high performance, but large-area utilization is limited by difficulties in their processability.

  8. Electrical characterization of S/C conductor for the CMS solenoid

    CERN Document Server

    Fabbricatore, P; Farinon, S; Greco, Michela; Kircher, F; Musenich, R

    2005-01-01

    The Compact Muon Solenoid (CMS) is one of the general-purpose detectors to be provided for the LHC project at CERN. The design field of the CMS superconducting magnet is 4 T, the magnetic length is 12.5 m and the free bore is 6 m. The coil is wound from 20 high purity aluminum-stabilized NbTi conductors with a total length of 45 km. The main peculiarity of the CMS magnet among other existing thin detector solenoids is its sandwich-type aluminum-stabilized superconductor. This special feature was chosen in order to have a mechanically self-supporting winding structure. We measured the critical current of all the 21 finished conductors in fields up to 6 T using the Ma.Ri.S.A. test facility at INFN-Genova. We compare these results with the critical current of single strands measured by CEA- Saclay, extracted from the conductor after the co-extrusion. A comparison among the measurements provides information about the possible critical current degradation and assures an accurate quality control of the conductor pr...

  9. Inkjet printing of multifilamentary YBCO for low AC loss coated conductors

    International Nuclear Information System (INIS)

    Hopkins, S C; Joseph, D; Mitchell-Williams, T B; Glowacki, B A; Calleja, A; Vlad, V R; Vilardell, M; Ricart, S; Granados, X; Puig, T; Obradors, X; Usoskin, A; Falter, M; Bäcker, M

    2014-01-01

    Considerable progress has been made with the development of REBCO coated conductors in recent years, and high performance conductors are available commercially. For many applications, however, the cost remains prohibitive, and AC losses discourage their selection for higher frequency applications. Chemical solution deposition (CSD) methods are attractive for low-cost, scalable preparation of buffer and superconductor layers, and in many respects inkjet printing is the method of choice, permitting non-contact deposition with minimal materials wastage and excellent control of coating thickness. Highly textured coatings of YBCO and Gd-doped CeO 2 have previously been reported on buffered metal substrates. Inkjet printing also introduces the possibility of patterning - directly depositing two and three dimensional structures without subtractive processing - offering a low-cost route to coated conductors with reduced AC losses. In this contribution, the inkjet deposition of superconducting YBCO tracks is reported on industrially relevant buffered metal substrates both by direct printing and an inverse patterning approach. In the latter approach, ceria tracks were printed reported, which are a candidate both for resistive filament spacers and buffer layers. TFA-based precursor solutions have been printed on SS/ABAD-YSZ/CeO 2 and Ni-W/LZO/CeO 2 RABiTS substrates, and the resulting multifilamentary samples characterised by microscopy and scanning Hall probe measurements. The prospects for future inkjet-printed low AC loss coated conductors are discussed, including control of interfilamentary resistivity and bridging, transposed filamentary structures and stabilisation material.

  10. Edge effects on forces and magnetic fields produced by a conductor moving past a magnet

    Energy Technology Data Exchange (ETDEWEB)

    Mulcahy, T.M.; Hull, J.R.; Almer, J.D. (Argonne National Lab., IL (United States)); Rossing, T.D. (Northern Illinois Univ., De Kalb, IL (United States))

    1992-01-01

    Experiments have been performed to further understand the forces acting on magnets moving along and over the edge of a continuous conducting sheet and to produce a comprehensive data set for the validation of analysis methods. Mapping the magnetic field gives information about the eddy currents induced in the conductor, which agrees with numerical calculations.

  11. Edge effects on forces and magnetic fields produced by a conductor moving past a magnet

    Energy Technology Data Exchange (ETDEWEB)

    Mulcahy, T.M.; Hull, J.R.; Almer, J.D. [Argonne National Lab., IL (United States); Rossing, T.D. [Northern Illinois Univ., De Kalb, IL (United States)

    1992-04-01

    Experiments have been performed to further understand the forces acting on magnets moving along and over the edge of a continuous conducting sheet and to produce a comprehensive data set for the validation of analysis methods. Mapping the magnetic field gives information about the eddy currents induced in the conductor, which agrees with numerical calculations.

  12. Electrochemical H-D isotope effect at metal-perovskite proton conductor interfaces

    DEFF Research Database (Denmark)

    Kek, D.; Bonanos, N.

    1999-01-01

    The H-D isotope effect on the electrode kinetics of a metal-proton conductor interface has been investigated. The current-voltage behaviour depends on the nature of the electrode (Ni, Ag), the atmosphere (H(2), D(2)), the partial pressures of the gases, and the temperature. The isotope effect was...

  13. Impact of corrosion on the reliability of low voltage cables with aluminium conductors

    NARCIS (Netherlands)

    van Deursen, A.; Kruizinga, B.; Wouters, P.A.A.F.; Steennis, E.F.

    2017-01-01

    Aluminium is widely used as conductor material for power cables, but corrosion taking place under specific circumstances can have impact on its reliability. Aluminium corrosion under the influence of an alternating current was studied experimentally. Submerged cable segments with inflicted damage

  14. Externalized conductors and insulation failure in Biotronik defibrillator leads: History repeating or a false alarm?

    Science.gov (United States)

    De Maria, Elia; Borghi, Ambra; Bonetti, Lorenzo; Fontana, Pier Luigi; Cappelli, Stefano

    2017-02-16

    Conductor externalization and insulation failure are frequent complications with the recalled St. Jude Medical Riata implantable cardioverter-defibrillator (ICD) leads. Conductor externalization is a "unique" failure mechanism: Cables externalize through the insulation ("inside-out" abrasion) and appear outside the lead body. Recently, single reports described a similar failure also for Biotronik leads. Moreover, some studies reported a high rate of electrical dysfunction (not only insulation failure) with Biotronik Linox leads and a reduced survival rate in comparison with the competitors. In this paper we describe the case of a patient with a Biotronik Kentrox ICD lead presenting with signs of insulation failure and conductor externalization at fluoroscopy. Due to the high risk of extraction we decided to implant a new lead, abandoning the damaged one; lead reimplant was uneventful. Subsequently, we review currently available literature about Biotronik Kentrox and Linox ICD lead failure and in particular externalized conductors. Some single-center studies and a non-prospective registry reported a survival rate between 88% and 91% at 5 years for Linox leads, significantly worse than that of other manufacturers. However, the preliminary results of two ongoing multicenter, prospective registries (GALAXY and CELESTIAL) showed 96% survival rate at 5 years after implant, well within industry standards. Ongoing data collection is needed to confirm longer-term performance of this family of ICD leads.

  15. [Measurement of the electric field of the heart in a homogeneous volume conductor].

    Science.gov (United States)

    Tsukerman, B M; Titomir, L I

    1975-01-01

    The paper describes a technique and some results of experimental measurements of electrical potentials generated by an isolated dog heart in homogeneous conductor, drawing equipotential maps of the field, and calculating the characteristics of the dipole equivalent generator of the heart. The form of potential distribution on a spherical surface around the heart and its ideal orthogonal vectorcardiograms are discussed.

  16. Development of cube textured Ni-W alloy substrates used for coated conductors

    DEFF Research Database (Denmark)

    Suo, Hongli; Ma, Lin; Gao, Mangmang

    2014-01-01

    It is considered as a challenge for RABiTS route to get cube textured Ni-W alloy substrates with high mechanical and magnetic properties for coated conductors. The works of our group in recent years are summarized about different Ni-W substrates with high W content and composite tapes made by RABiTS...

  17. Active Power Flow Optimization of Industrial Power Supply with Regard to the Transmission Line Conductor Heating

    Directory of Open Access Journals (Sweden)

    Leyzgold D.Yu.

    2015-04-01

    Full Text Available This article studies the problem of the transmission line conductor heating effect on the active power flows optimization in the local segment of industrial power supply. The purpose is to determine the optimal generation rating of the distributed power sources, in which the power flow values will correspond to the minimum active power losses in the power supply. The timeliness is the need to define the most appropriate rated power values of distributed sources which will be connected to current industrial power supply. Basing on the model of active power flow optimization, authors formulate the description of the nonlinear transportation problem considering the active power losses depending on the transmission line conductor heating. Authors proposed a new approach to the heating model parameters definition based on allowable current loads and nominal parameters of conductors as part of the optimization problem. Analysis of study results showed that, despite the relatively small active power losses reduction to the tune 0,45% due to accounting of the conductors heating effect for the present configuration of power supply, there are significant fluctuations in the required generation rating in nodes of the network to 9,32% within seasonal changes in the outer air temperature. This fact should be taken into account when selecting the optimum power of distributed generation systems, as exemplified by an arbitrary network configuration.

  18. Mechanical properties of high-current multifilamentary Nb3Sn conductors

    International Nuclear Information System (INIS)

    Scanlan, R.M.; Hoard, R.W.; Cornish, D.N.; Zbasnik, J.P.

    1980-01-01

    Nb 3 Sn is a strain-sensitive superconductor which exhibits large changes in properties for strains of less than 1 percent. The critical current density at 12 T undergoes a reversible degradation of a factor of two for compressive strains of about 1 percent and undergoes an irreversible degradation for tensile strains on the Nb 3 Sn greater than 0.2 percent. Consequently, the successful application of Nb 3 Sn in large high-field magnets requires a complete understanding of the mechanical properties of the conductor. One conductor which is being used for many applications consists of filaments of Nb 3 Sn in a bronze matrix, and much progress has been made in understanding the mechanical behavior of this composite. The Nb 3 Sn filaments are placed in compression due to the differential thermal contraction between Nb 3 Sn and bronze which occurs when the composite is cooled from the Nb 3 Sn formation temperature (typically 700 0 C) to the 4.2 0 K operating temperature. The general behavior of the critical current when this conductor is subjected to a tensile stress is an increase to a maximum when the compressive strain on the Nb 3 Sn is relieved, followed by a decrease as the Nb 3 Sn filemants are placed in tension. The degree of precompression is controlled largely by the ratio of bronze to Nb 3 Sn in the conductor

  19. Analytical investigation in bending characteristic of twisted stacked-tape cable conductor

    International Nuclear Information System (INIS)

    Takayasu, Makoto; Chiesa, Luisa

    2015-01-01

    An analytical model to evaluate bending strains of a twisted stack-tape cable (TSTC) conductor has been developed. Through a comparison with experimental results obtained for a soldered 32-tape YBCO TSTC conductor, it has been found that a Perfect-Slip Model (PSM) taking into account the slipping between tapes in a stacked-tape cable during bending gives much better estimation of the bending performance compared to a No-Slip Model (NSM). In the PSM case the tapes can slip so that the internal longitudinal axial strain can be released. The longitudinal strains of compression and tension regions along the tape are balanced in one twist-pitch and cancel out evenly in a long cable. Therefore, in a cable the strains due to bending can be minimized. This is an important advantage of a TSTC conductor. The effect of the cable diameter size on the bending strain is also expected to be minor, and all tapes composing a TSTC conductor have the same strain response under bending, therefore the cable critical current can be characterized from a single tape behaviour. (paper)

  20. Analytical investigation in bending characteristic of twisted stacked-tape cable conductor

    Science.gov (United States)

    Takayasu, Makoto; Chiesa, Luisa

    2015-12-01

    An analytical model to evaluate bending strains of a twisted stack-tape cable (TSTC) conductor has been developed. Through a comparison with experimental results obtained for a soldered 32-tape YBCO TSTC conductor, it has been found that a Perfect-Slip Model (PSM) taking into account the slipping between tapes in a stacked-tape cable during bending gives much better estimation of the bending performance compared to a No-Slip Model (NSM). In the PSM case the tapes can slip so that the internal longitudinal axial strain can be released. The longitudinal strains of compression and tension regions along the tape are balanced in one twist-pitch and cancel out evenly in a long cable. Therefore, in a cable the strains due to bending can be minimized. This is an important advantage of a TSTC conductor. The effect of the cable diameter size on the bending strain is also expected to be minor, and all tapes composing a TSTC conductor have the same strain response under bending, therefore the cable critical current can be characterized from a single tape behaviour.