Enhancement of conductivity due to local disorder in a one-dimensional conductor

International Nuclear Information System (INIS)

Morifuji, Masato; Maeda, Yusuke

2011-01-01

We theoretically investigate electron transport in a one-dimensional conductor with a locally disordered potential by using the non-equilibrium Green’s function theory. It is found that, by changing the energy of a site in a one-dimensional atomic chain, the electron conductivity can be larger when the modulated site energy is smaller than that of the other sites. This contradicts the conventional picture that an electron is scattered by the disorder of the potential, because such a scattering process usually causes resistivity. We show that the enhancement of conductivity that seems contradictory to the conventional picture of electron motion is explained by the change of energy of quasi bound states in the conductor. (paper)

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

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.

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

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.

The Hall effect in the organic conductor TTF–TCNQ: choice of geometry for accurate measurements of a highly anisotropic system

DEFF Research Database (Denmark)

Tafra, E; Čulo, M; Basletić, M

2012-01-01

We have measured the Hall effect on recently synthesized single crystals of the quasi-one-dimensional organic conductor TTF–TCNQ (tetrathiafulvalene–tetracyanoquinodimethane), a well known charge transfer complex that has two kinds of conductive stacks: the donor (TTF) and the acceptor (TCNQ) cha...

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

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.

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)

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

Observation of hidden Fermi surface nesting in a two dimensional conductor

International Nuclear Information System (INIS)

Breuer, K.; Stagerescu, C.; Smith, K.E.; Greenblatt, M.; Ramanujachary, K.

1996-01-01

We report the first direct measurement of hidden Fermi surface nesting in a two dimensional conductor. The system studied was Na 0.9 Mo 6 O 17 , and the measured Fermi surface consists of electron and hole pockets that can be combined to form sets of pseudo-one-dimensional Fermi surfaces, exhibiting the nesting necessary to drive a Peierls transition to a charge density wave state. The observed nesting vector is shown to be in excellent agreement with theory. copyright 1996 The American Physical Society

Correlations, dimensionality and instabilities in organic superconductors

International Nuclear Information System (INIS)

Jerome, D.; Wzietek, P.; Bourbonnais, C.

1995-01-01

We discuss the role of Coulombic repulsion in organic superconductors exhibiting quasi-one-dimensional transport properties. A recent investigation in high magnetic fields shows that the charge localization occurring at low temperature in a 1-D half-fillled band is suppressed by the 1-D to 2-D (3-D) cross-over in selenium compounds. However, a localization around 30K in the non-ordered phase can be reactivated by the application of a high transverse magnetic field. This phenomenon provides an interpretation for the large transverse magnetoresistance observed in quasi-1-D conductors with open Fermi surfaces. The intermediate (strong) coupling limit is valid for the spin degree of freedom whereas the charge is governed by the strength of the Umklapp scattering varying by a large factor from sulfur to selenium compounds and under pressure. ((orig.))

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....

Low-Symmetry Gap Functions of Organic Superconductors

Science.gov (United States)

Mori, Takehiko

2018-04-01

Superconducting gap functions of various low-symmetry organic superconductors are investigated starting from the tight-binding energy band and the random phase approximation by numerically solving Eliashberg's equation. The obtained singlet gap function is approximately represented by an asymmetrical dx2 - y2 form, where two cosine functions are mixed in an appropriate ratio. This is usually called d + s wave, where the ratio of the two cosine functions varies from 1:1 in the two-dimensional limit to 1:0 in the one-dimensional limit. A single cosine function does not make a superconducting gap in an ideal one-dimensional conductor, but works as a relevant gap function in quasi-one-dimensional conductors with slight interchain transfer integrals. Even when the Fermi surface is composed of small pockets, the gap function is obtained supposing a globally connected elliptical Fermi surface. In such a case, we have to connect the second energy band in the second Brillouin zone. The periodicity of the resulting gap function is larger than the first Brillouin zone. This is because the susceptibility has peaks at 2kF, where the periodicity has to be twice the size of the global Fermi surface. In general, periodicity of gap function corresponds to one electron or two molecules in the real space. In the κ-phase, two axes are nonequivalent, but the exact dx2 - y2 symmetry is maintained because the diagonal transfer integral introduced to a square lattice is oriented to the node direction of the dx2 - y2 wave. By contrast, the θ-phase gap function shows considerable anisotropy because a quarter-filled square lattice has a different dxy symmetry.

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 .

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.

Non-periodic one-dimensional ideal conductors and integrable turbulence

Energy Technology Data Exchange (ETDEWEB)

Zakharov, Dmitry V. [Courant Institute of Mathematical Sciences, New York University, 251 Mercer Street, New York, NY, 10012 (United States); Zakharov, Vladimir E. [Department of Mathematics, University of Arizona, Tucson, AZ, 85791 (United States); Dyachenko, Sergey A., E-mail: sdyachen@math.uiuc.edu [Department of Mathematics, University of Illinois, Urbana-Champaign, IL, 61801 (United States)

2016-12-01

Highlights: • An efficient procedure for construction of non-periodic, non-vanishing reflectionless potentials is presented. • The analytical procedure is reinforced by numerical simulation that presents some of these potentials. • The present work is a key ingredient for the study of integrable turbulence and statistical description of “solitonic gas”. - Abstract: To relate the motion of a quantum particle to the properties of the potential is a fundamental problem of physics, which is far from being solved. Can a medium with a potential which is neither periodic nor quasi-periodic be a conductor? That question seems to have been never addressed, despite being both interesting and having practical importance. Here we propose a new approach to the spectral problem of the one-dimensional Schrödinger operator with a bounded potential. We construct a wide class of potentials having a spectrum consisting of the positive semiaxis and finitely many bands on the negative semiaxis. These potentials, which we call primitive, are reflectionless for positive energy and in general are neither periodic nor quasi-periodic. Moreover, they can be stochastic, and yet allow ballistic transport, and thus describe one-dimensional ideal conductors. Primitive potentials also generate a new class of solutions of the KdV hierarchy. Stochastic primitive potentials describe integrable turbulence, which is important for hydrodynamics and nonlinear optics. We construct the potentials by numerically solving a system of singular integral equations. We hypothesize that finite-gap potentials are a subclass of primitive potentials, and prove this in the case of one-gap potentials.

Surface characterization and surface electronic structure of organic quasi-one-dimensional charge transfer salts

DEFF Research Database (Denmark)

Sing, M.; Schwingenschlögl, U.; Claessen, R.

2003-01-01

We have thoroughly characterized the surfaces of the organic charge-transfer salts TTF-TCNQ and (TMTSF)(2)PF6 which are generally acknowledged as prototypical examples of one-dimensional conductors. In particular x-ray-induced photoemission spectroscopy turns out to be a valuable nondestructive...

Defects in quasi-one dimensional oxide conductors: K0.3MoO3

International Nuclear Information System (INIS)

Smith, K.E.; Breuer, K.; Goldberg, D.; Greenblatt, M.; McCarroll, W.; Hulbert, S.L.

1995-01-01

The electronic structure of the prototypical quasi-one dimensional (ID) conductor K 0.3 MoO 3 has been studied using high resolution photoemission spectroscopy. In particular, the electronic structure of defects was investigated in order to understand the mechanism for charge density wave pinning and destruction of the Peierls transition. Defects were found to radically alter the electronic structure close to the Fermi level (E F ), thus strongly modifying the structure of the Fermi surface. While a low emission intensity at E F has been interpreted as evidence for a Luttinger liquid ground state in a 1D metal, the authors show that non-stoichiometric surfaces lead to similar effects. The nature of the ground state is discussed in the context of these results

Low AC Loss YBCO Coated Conductor Geometry by Direct Inkjet Printing

Energy Technology Data Exchange (ETDEWEB)

Rupich, Martin, Dr. [American Superconductor Corporation; Duckworth, Robert, Dr. [Oak Ridge National Laboratory

2009-10-01

The second generation (2G) high temperature superconductors (HTS) wire offers potential benefits for many electric power applications, including ones requiring filamentized conductors with low ac loss, such as transformers and fault current limiters. However, the use of 2G wire in these applications requires the development of both novel multi-filamentary conductor designs with lower ac losses and the development of advanced manufacturing technologies that enable the low-cost manufacturing of these filamentized architectures. This Phase I SBIR project focused on testing inkjet printing as a potential low-cost, roll-to-roll manufacturing technique to fabricate potential low ac loss filamentized architectures directly on the 2G template strips.

A two-dimensional finite element method to calculate the AC loss in superconducting cables, wires and coated conductors

Energy Technology Data Exchange (ETDEWEB)

Hong, Z; Jiang, Y; Pei, R; Coombs, T A [Electronic, Power and Energy Conversion Group, Engineering Department, University of Cambridge, CB2 1PZ (United Kingdom); Ye, L [Department of Electrical Power Engineering, CAU, P. O. Box 210, Beijing 100083 (China); Campbell, A M [Interdisciplinary Research Centre in Superconductivity, University of Cambridge, CB3 0HE (United Kingdom)], E-mail: Zh223@cam.ac.uk

2008-02-15

In order to utilize HTS conductors in AC electrical devices, it is very important to be able to understand the characteristics of HTS materials in the AC electromagnetic conditions and give an accurate estimate of the AC loss. A numerical method is proposed in this paper to estimate the AC loss in superconducting conductors including MgB{sub 2} wires and YBCO coated conductors. This method is based on solving a set of partial differential equations in which the magnetic field is used as the state variable to get the current and electric field distributions in the cross sections of the conductors and hence the AC loss can be calculated. This method is used to model a single-element and a multi-element MgB{sub 2} wires. The results demonstrate that the multi-element MgB{sub 2} wire has a lower AC loss than a single-element one when carrying the same current. The model is also used to simulate YBCO coated conductors by simplifying the superconducting thin tape into a one-dimensional region where the thickness of the coated conductor can be ignored. The results show a good agreement with the measurement.

Physical Properties of (NH4)2Pt(CN)4[Clo.42].3H2O: A new Quasi-One-Dimensional Conductor

DEFF Research Database (Denmark)

Carneiro, Kim; Petersen, A. S.; Underhill, A. E.

1979-01-01

The quasi-one-dimensional conductor (NH4)2[Pt(CN)4]Cl0.42·3H2O, ACP(Cl), has been studied experimentally by means of electrical conduction measurements, x-ray diffuse scattering, and neutron inelastic scattering. This allows the determination of all the physical parameters of interest for the the......The quasi-one-dimensional conductor (NH4)2[Pt(CN)4]Cl0.42·3H2O, ACP(Cl), has been studied experimentally by means of electrical conduction measurements, x-ray diffuse scattering, and neutron inelastic scattering. This allows the determination of all the physical parameters of interest...

Distribution Analysis of the Local Critical Temperature and Current Density in YBCO Coated Conductors using Low-temperature Scanning Laser and Hall Probe Microscopy

International Nuclear Information System (INIS)

Park, S. K.; Cho, B. R.; Park, H. Y.; Ri, H. C.

2011-01-01

Distribution of the local critical temperature and current density in YBCO coated conductors were analyzed using Low-temperature Scanning Laser and Hall Probe Microscopy (LTSLHPM). We prepared YBCO coated conductors of various bridge types to study the spatial distribution of the critical temperature and the current density in single and multi bridges. LTSLHPM system was modified for detailed linescan or two-dimensional scan both scanning laser and scanning Hall probe method simultaneously. We analyzed the local critical temperature of single and multi bridges from series of several linescans of scanning laser microscopy. We also investigated local current density and hysteresis curve of single bridge from experimental results of scanning Hall probe microscopy.

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)

Low-Dimensional Organic Tin Bromide Perovskites and Their Photoinduced Structural Transformation.

Science.gov (United States)

Zhou, Chenkun; Tian, Yu; Wang, Mingchao; Rose, Alyssa; Besara, Tiglet; Doyle, Nicholas K; Yuan, Zhao; Wang, Jamie C; Clark, Ronald; Hu, Yanyan; Siegrist, Theo; Lin, Shangchao; Ma, Biwu

2017-07-24

Hybrid organic-inorganic metal halide perovskites possess exceptional structural tunability, with three- (3D), two- (2D), one- (1D), and zero-dimensional (0D) structures on the molecular level all possible. While remarkable progress has been realized in perovskite research in recent years, the focus has been mainly on 3D and 2D structures, with 1D and 0D structures significantly underexplored. The synthesis and characterization of a series of low-dimensional organic tin bromide perovskites with 1D and 0D structures is reported. Using the same organic and inorganic components, but at different ratios and reaction conditions, both 1D (C 4 N 2 H 14 )SnBr 4 and 0D (C 4 N 2 H 14 Br) 4 SnBr 6 can be prepared in high yields. Moreover, photoinduced structural transformation from 1D to 0D was investigated experimentally and theoretically in which photodissociation of 1D metal halide chains followed by structural reorganization leads to the formation of a more thermodynamically stable 0D structure. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

Phase slip process and charge density wave dynamics in a one dimensional conductor

Science.gov (United States)

Habiballah, N.; Zouadi, M.; Arbaoui, A.; Qjani, M.; Dumas, J.

In this paper, we study the phase slip effect on the charge density wave (CDW) dynamics in a one-dimensional conductor in the weak pinning limit. A considerable enhancement of JCDW is observed in the presence of phase slips. In addition, a spatial dependence of the CDW current density JCDW is also studied showing that a decrease of JCDW with distance from the current contact occurs. The results are discussed in terms the relationship between additional phase slips and the mobility of phase dislocations nucleated at electrical contacts.

Optical properties of low-dimensional materials

CERN Document Server

Ogawa, T

1998-01-01

This book surveys recent theoretical and experimental studies of optical properties of low-dimensional materials. As an extended version of Optical Properties of Low-Dimensional Materials (Volume 1, published in 1995 by World Scientific), Volume 2 covers a wide range of interesting low-dimensional materials including both inorganic and organic systems, such as disordered polymers, deformable molecular crystals, dilute magnetic semiconductors, SiGe/Si short-period superlattices, GaAs quantum wires, semiconductor microcavities, and photonic crystals. There are excellent review articles by promis

Scanning Hall-probe microscopy system for two-dimensional imaging of critical current density in RE-123 coated conductors

International Nuclear Information System (INIS)

Higashikawa, K.; Inoue, M.; Kawaguchi, T.; Shiohara, K.; Imamura, K.; Kiss, T.; Iijima, Y.; Kakimoto, K.; Saitoh, T.; Izumi, T.

2011-01-01

Nondestructive characterization method of in-plane distribution of critical current density for coated conductors. Current distribution in a coated conductor compared with that from theoretical analysis. Relationship between local critical current density and local magnetic field. We have developed a characterization method for two-dimensional imaging of critical current density in coated conductors (CCs) based on scanning Hall-probe microscopy (SHPM). The distributions of the magnetic field around a sample were measured for several different conditions of external magnetic fields, and then were converted to those of the sheet current density which flowed to shield the external magnetic field or to trap the penetrated magnetic field. As a result, it was found that the amplitude of the sheet current density corresponded to that of critical current density almost in all the area of the sample except for the region where current direction changed. This indicates that we could obtain an in-plane distribution of the critical current density with a spatial resolution of around 100 μm in non-destructive manner by this method. We believe that this measurement will be a multifunctional and comprehensive characterization method for coated conductors.

Estimation of πd-Interactions in Organic Conductors Including Magnetic Anions

Science.gov (United States)

Mori, Takehiko; Katsuhara, Mao

2002-03-01

Magnetic interactions in organic conductors including magnetic anions, such as λ-(BETS)2FeCl4 and κ-(BETS)2FeX4 [X = Cl and Br], are estimated from intermolecular overlap integrals; the overlaps between anions afford Jdd, and those between anions and donors give Jπ d. From this, the most stable spin alignments are decided, and such quantities as the Néel and Weiss temperatures, as well as the magnitude of spin polarization on the π-molecules are evaluated on the basis of the mean-field theory of πd-systems. The calculation is extended to several other πd-conductors, which are classified depending on the relative magnitudes of the direct dd- and indirect πd-interactions.

Estimation of magnetic relaxation property for CVD processed YBCO-coated conductors

International Nuclear Information System (INIS)

Takahashi, Y.; Kiuchi, M.; Otabe, E.S.; Matsushita, T.; Shikimachi, K.; Watanabe, T.; Kashima, N.; Nagaya, S.

2010-01-01

Ion Beam Assist Deposition/Chemical Vapor Deposition(IBAD/CVD)-processed YBCO-coated conductors with high critical current density J c at high magnetic fields are expected to be applied to superconducting equipments such as superconducting magnetic energy storage (SMES). For application to superconducting magnet in SMES one of the most important properties for superconductors is the relaxation property of superconducting current. In this paper, the relaxation property is investigated for IBAD/CVD-processed YBCO-coated conductors of the superconducting layer in the range of 0.18-0.90 μm. This property can be quantitatively characterized by the apparent pinning potential, U 0 *. It is found that U 0 * takes a smaller value due to the two-dimensional pinning mechanism at high magnetic fields for conductor with thinner superconducting layer. Although U 0 * decreases with increasing thickness at low magnetic fields at 20 K, it increases at high magnetic fields. The results are theoretically explained by the model of the flux creep and flow based on the dimensionality of flux pinning. Scaling analysis is examined for the dependence of U 0 * on the magnetic field, temperature and the layer thickness.

Theory of thermionic emission from a two-dimensional conductor and its application to a graphene-semiconductor Schottky junction

Science.gov (United States)

Trushin, Maxim

2018-04-01

The standard theory of thermionic emission developed for three-dimensional semiconductors does not apply to two-dimensional materials even for making qualitative predictions because of the vanishing out-of-plane quasiparticle velocity. This study reveals the fundamental origin of the out-of-plane charge carrier motion in a two-dimensional conductor due to the finite quasiparticle lifetime and huge uncertainty of the out-of-plane momentum. The theory is applied to a Schottky junction between graphene and a bulk semiconductor to derive a thermionic constant, which, in contrast to the conventional Richardson constant, is determined by the Schottky barrier height and Fermi level in graphene.

A neutron scattering study of the quasi-one-dimensional conductor (TaSe{sub 4}){sub 2}I

Energy Technology Data Exchange (ETDEWEB)

Lorenzo, J.E.; Currat, R. [Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9 (France); Monceau, P. [Centre de Recherches sur les Tres Basses Temperatures, associe a l' Universite Joseph Fourier, CNRS, BP 166, 38042 Grenoble Cedex 9 (France); Hennion, B. [Laboratoire Leon Brillouin, Centre d' Etudes de Saclay, 91191 Gif-sur-Yvette Cedex (France); Berger, H.; Levy, F. [Institut de Physique Appliquee, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland)

1998-06-15

The Peierls phase transition in the quasi-one-dimensional conductor (TaSe{sub 4}){sub 2}I is investigated by means of elastic and inelastic neutron scattering. The effective critical exponent {beta}, extracted from the temperature dependence of the integrated intensity from the CDW satellite reflections, is anomalously low, suggesting that the phase transition may be of first order. The intensity distribution among symmetry-related satellite reflections indicates a domain structure with slowly fluctuating domain populations. Correlation lengths associated with the diverging 'central peak' are determined and are found to be nearly isotropic, at variance with results obtained on other quasi-one-dimensional compounds, such as platinum chains (KCP) or blue bronze, K{sub 0.3}MoO{sub 3}. Doping with 1.2% Nb has a severe effect on the modulated state. The low-temperature satellites are replaced by a diffuse scattering distribution elongated along c*. The absence of a phonon soft mode and the presence of a diverging central peak at the phase transition is interpreted within the framework of strong electron-phonon coupling. Finally, we propose a Ginzburg-Landau phenomenological model, where the interplay between the electronically coupled optical-like order parameter (Ta-atom tetramerization along the chain axis) and the elastic deformations lies at the origin of the phase transition in (TaSe{sub 4}){sub 2}I. (author)

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.

NATO Advanced Study Institute on Lower-Dimensional Systems and Molecular Electronics

CERN Document Server

Day, Peter; Papavassiliou, George

1990-01-01

This volume represents the written account of the NATO Advanced Study Institute "Lower-Dimensional Systems and Molecular Electronics" held at Hotel Spetses, Spetses Island, Greece from 12 June to 23 June 1989. The goal of the Institute was to demonstrate the breadth of chemical and physical knowledge that has been acquired in the last 20 years in inorganic and organic crystals, polymers, and thin films, which exhibit phenomena of reduced dimensionality. The interest in these systems started in the late 1960's with lower-dimensional inorganic conductors, in the early 1970's with quasi-one-dimensional crystalline organic conductors. which by 1979 led to the first organic superconductors, and, in 1977, to the fITSt conducting polymers. The study of monolayer films (Langmuir-Blodgett films) had progressed since the 1930's, but reached a great upsurge in . the early 1980's. The pursuit of non-linear optical phenomena became increasingly popular in the early 1980's, as the attention turned from inorganic crystals t...

Physics of low-dimensional systems

International Nuclear Information System (INIS)

Anon.

1989-01-01

The physics of low-dimensional systems has developed in a remarkable way over the last decade and has accelerated over the last few years, in particular because of the discovery of the new high temperature superconductors. The new developments started more than fifteen years ago with the discovery of the unexpected quasi-one-dimensional character of the TTF-TCNQ. Since then the field of conducting quasi-one-dimensional organic system have been rapidly growing. Parallel to the experimental work there has been an important theoretical development of great conceptual importance, such as charge density waves, soliton-like excitations, fractional charges, new symmetry properties etc. A new field of fundamental importance was the discovery of the Quantum Hall Effect in 1980. This field is still expanding with new experimental and theoretical discoveries. In 1986, then, came the totally unexpected discovery of high temperature superconductivity which started an explosive development. The three areas just mentioned formed the main themes of the Symposium. They do not in any way exhaust the progress in low-dimensional physics. We should mention the recent important development with both two-dimensional and one-dimensional and even zero-dimensional structures (quantum dots). The physics of mesoscopic systems is another important area where the low dimensionality is a key feature. Because of the small format of this Symposium we could unfortunately not cover these areas

Common phase diagram for low-dimensional superconductors

International Nuclear Information System (INIS)

Michalak, Rudi

2003-01-01

A phenomenological phase diagram which has been derived for high-temperature superconductors from NMR Knight-shift measurements of the pseudogap is compared to the phase diagram that is obtained for organic superconductors and spin-ladder superconductors, both low-dimensional systems. This is contrasted to the phase diagram of some Heavy Fermion superconductors, i.e. superconductors not constrained to a low dimensionality

Topological organization of (low-dimensional) chaos

International Nuclear Information System (INIS)

Tufillaro, N.B.

1992-01-01

Recent progress toward classifying low-dimensional chaos measured from time series data is described. This classification theory assigns a template to the time series once the time series is embedded in three dimensions. The template describes the primary folding and stretching mechanisms of phase space responsible for the chaotic motion. Topological invariants of the unstable periodic orbits in the closure of the strange set are calculated from the (reconstructed) template. These topological invariants must be consistent with ampersand ny model put forth to describe the time series data, and are useful in invalidating (or gaining confidence in) any model intended to describe the dynamical system generating the time series

Evaluation of a cryostable low-loss conductor for pulsed field applications

International Nuclear Information System (INIS)

Wollan, J.J.; Walker, M.S.; Zeitlin, B.A.; Pollack, D.A.; Shen, S.S.

1980-01-01

A cryostable, low loss conductor as the basic strand in a 50 kA cable for a 20 MJ prototype, tokamak induction heating coil has been developed, fabricated, and evaluated. The conductor has a copper matrix multifilamentary NbTi core surrounded by a CuNi ring and stabilizing copper segmented by radial CuNi fins. Pulsed loss measurements have been made up to 2.2 T and for decay times from 0.7 to 278 ms. Measurements made on samples with various twists and portions etched away have allowed accurate evaluation of the loss components. Stability measurements were also made on insulated and uninsulated single strands and on subcables. Measured recovery heat flux for the bare strand is about 0.3 W/cm 2 ; however, the application of a 0.0005 in. layer of Omega insulation increases the value to about 0.5 W/cm 2

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

Three dimensional optimization of small-scale axial turbine for low temperature heat source driven organic Rankine cycle

International Nuclear Information System (INIS)

Al Jubori, Ayad; Al-Dadah, Raya K.; Mahmoud, Saad; Bahr Ennil, A.S.; Rahbar, Kiyarash

2017-01-01

Highlights: • Three-dimensional optimization of axial turbine stage is presented. • Six organic fluids suitable for low-temperature heat source are considered. • Three-dimensional optimization has been done for each working fluid. • The results showed highlight the potential of optimization technique. • The performance of optimized turbine has been improved off-design conditions. - Abstract: Advances in optimization techniques can be used to enhance the performance of turbines in various applications. However, limited work has been reported on using such optimization techniques to develop small-scale turbines for organic Rankine cycles. This paper investigates the use of multi-objective genetic algorithm to optimize the stage geometry of a small-axial subsonic turbine. This optimization is integrated with organic Rankine cycle analysis using wide range of high density organic working fluids like R123, R134a, R141b, R152a, R245fa and isobutane suitable for low temperature heat sources <100 °C such as solar energy to achieve the best turbine design and highest organic Rankine cycle efficiency. The isentropic efficiency of the turbine in most of the reported organic Rankine cycle studies was assumed constant, while the current work allows the turbine isentropic efficiency to change (dynamic value) with both operating conditions and working fluids. Three-dimensional computational fluid dynamics analysis and multi-objective genetic algorithm optimization were performed using three-dimensional Reynolds-averaged Navier-Stokes equations with k-omega shear stress transport turbulence model in ANSYS"R"1"7-CFX and design exploration for various working fluids. The optimization was carried out using eight design parameters for the turbine stage geometry optimization including stator and rotor number of blades, rotor leading edge beta angle, trailing edge beta angle, stagger angle, throat width, trailing half wedge angle and shroud tip clearance. Results showed that

Alternating current losses of a 10 metre long low loss superconducting cable conductor determined from phase sensitive measurements

DEFF Research Database (Denmark)

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

1999-01-01

The ac loss of a superconducting cable conductor carrying an ac current is small. Therefore the ratio between the inductive (out-of-phase) and the resistive (in-phase) voltages over the conductor is correspondingly high. In vectorial representations this results in phase angles between the current......-in amplifiers can be exploited. In this paper we present the results from ac-loss measurements on a low loss 10 metre long high temperature superconducting cable conductor using such a correction scheme. Measurements were carried out with and without a compensation circuit that could reduce-the inductive...... voltage. The 1 mu V cm(-1) critical current of the conductor was 3240 A at 77 K. At an rms current of 2 kA (50 Hz) the ac loss was derived to be 0.6 +/- 0.15 W m(-1). This is, to the best of our knowledge, the lowest value of ac loss of a high temperature superconducting cable conductor reported so far...

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

Simulation of a two-dimensional sheath over a flat insulator-conductor interface on a radio-frequency biased electrode in a high-density plasma

International Nuclear Information System (INIS)

Kim, Doosik; Economou, Demetre J.

2004-01-01

A combined fluid/Monte Carlo (MC) simulation was developed to study the two-dimensional (2D) sheath over a flat insulator/conductor interface on a radio-frequency (rf) biased electrode in a high-density plasma. The insulator capacitance increased the local impedance between the plasma and the bias voltage source. Thus, for uniform ion density and electron temperature far away from the wall, the sheath potential over the insulator was only a fraction of that over the conductor, resulting in a thinner sheath over the insulator. The fluid model provided the spatiotemporal profiles of the 2D sheath electric field. These were used as input to the MC simulation to compute the ion energy distribution (IED) and ion angular distribution (IAD) at different locations on the surface. The ion flux, IED, and IAD changed drastically across the insulator/conductor interface due to the diverging rf electric field in the distorted sheath. The ion flux was larger on the conductor at the expense of that on the insulator. Both the ion impact angle and angular spread increased progressively as the material interface was approached. The ion impact energy and energy spread were smaller on the insulator as compared to the conductor. For given plasma parameters, as the insulator thickness was increased, the sheath potential and thickness over the insulator decreased, and sheath distortion became more pronounced

Analytical Solutions of Electromagnetic Fields from Current Dipole Moment on Spherical Conductor in a Low-Frequency Approximation

International Nuclear Information System (INIS)

Okita, Taishi; Takagi, Toshiyuki

2010-01-01

We analytically derive the solutions for electromagnetic fields of electric current dipole moment, which is placed in the exterior of the spherical homogeneous conductor, and is pointed along the radial direction. The dipole moment is driven in the low frequency f = 1 kHz and high frequency f = 1 GHz regimes. The electrical properties of the conductor are appropriately chosen in each frequency. Electromagnetic fields are rigorously formulated at an arbitrary point in a spherical geometry, in which the magnetic vector potential is straightforwardly given by the Biot-Savart formula, and the scalar potential is expanded with the Legendre polynomials, taking into account the appropriate boundary conditions at the spherical surface of the conductor. The induced electric fields are numerically calculated along the several paths in the low and high frequency excitation. The self-consistent solutions obtained in this work will be of much importance in a wide region of electromagnetic induction problems. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

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.

The feasibility of low-mass conductors for toroidal superconducting magnets for SSC [Superconducting Super Collider] detectors

International Nuclear Information System (INIS)

Luton, J.N.

1990-01-01

An earlier study by Luton and Bonanos concluded that the design and fabrication of superconducting toroidal bending magnets would require a major effort but would be feasible. This study is an extension to examine the feasibility of low-mass conductors for such use. It included a literature search, consultations, with conductor manufacturers, and design calculations, but no experimental work. An unoptimized sample design that used a residual resistivity ratio for aluminum of 1360 and a current density of 3.5 kA/cm 2 over the uninsulated conductor for a 4.5-T toroid with 1 GJ of stored energy obtained a hot-spot temperature of 120 K with a maximum dump voltage of 3.6 kV and 24% of the initial current inductively transferred into the shorted aluminum structure. The stability margin was 200 mJ/cm 3 of cable space. Limiting the quench pressure to 360 atm to give conservative stresses in the sheath and assuming that the whole flow path quenched immediately resulted in helium taps that could be a kilometer apart if the flow friction factor were the same as that experienced in the Westinghouse (W) Large Coil Task (LCT) coil. This indicates that the 520-m conductor length of each of the 72 individual coil segments of a toroid would be a single flow path. If some practical uncertainties can be favorably resolved by producing and testing sample conductors, the use of a conductor with clad-aluminum stabilizer and extruded aluminum-alloy sheath should be feasible and economical. 9 refs., 3 figs

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

Electronic and magnetic properties of organic conductors (DMET) sub 2 MBr sub 4 (M=Fe, Ga)

CERN Document Server

Enomoto, K; Enoki, T; Yamaura, J I

2003-01-01

(DMET) sub 2 MBr sub 4 (M=Fe, Ga) are isostructural organic conductors whose crystal structure consists of an alternate stacking of quasi one-dimensional chain-based donor layers and anion square lattices. The resistivity, ESR, magnetic susceptibility, magnetization, and magnetoresistance of these salts were investigated in order to clarify the correlation between the electronic structure and the magnetism. The electronic structures of both salts are metallic down to T sub M sub I - 40 K, below which a Mott insulating state is stabilized, accompanied by an SDW transition at T sub S sub D sub W - 25 K. The FeBr sub 4 salt with Fe sup 3 sup + (S=5/2) localized spins undergoes an antiferromagnetic transition at T sub N = 3.7 K. In the FeBr sub 4 salt, the magnetization curves, which show field-direction-dependent anomalies in addition to a spin-flop transition, are demonstrated to have a participation of donor pi-electron spins in the magnetization processes. The field dependence of the magnetoresistances below ...

A high critical current density MOCVD coated conductor with strong vortex pinning centers suitable for very high field use

International Nuclear Information System (INIS)

Chen, Z; Kametani, F; Larbalestier, D C; Chen, Y; Xie, Y; Selvamanickam, V

2009-01-01

We have made extensive low temperature and high field evaluations of a recent 2.1 μm thick coated conductor (CC) grown by metal-organic chemical vapor deposition (MOCVD) with a view to its use for high field magnet applications, for which its very strong Hastelloy substrate makes it very suitable. This conductor contains dense three-dimensional (Y,Sm) 2 O 3 nanoprecipitates, which are self-aligned in planes tilted ∼7 deg. from the tape plane. Very strong vortex pinning is evidenced by high critical current density J c values of ∼3.1 MA cm -2 at 77 K and ∼43 MA cm -2 at 4.2 K, and by a strongly enhanced irreversibility field H irr , which reaches that of Nb 3 Sn (∼28 T at 1.5 K) at 60 K, even in the inferior direction of H parallel c axis. At 4.2 K, J c values are ∼15% of the depairing current density J d , much the highest of any superconductor suitable for magnet construction.

A high critical current density MOCVD coated conductor with strong vortex pinning centers suitable for very high field use

Energy Technology Data Exchange (ETDEWEB)

Chen, Z; Kametani, F; Larbalestier, D C [National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310 (United States); Chen, Y; Xie, Y; Selvamanickam, V [SuperPower Incorporated, Schenectady, NY 12304 (United States)], E-mail: zhijun@asc.magnet.fsu.edu

2009-05-15

We have made extensive low temperature and high field evaluations of a recent 2.1 {mu}m thick coated conductor (CC) grown by metal-organic chemical vapor deposition (MOCVD) with a view to its use for high field magnet applications, for which its very strong Hastelloy substrate makes it very suitable. This conductor contains dense three-dimensional (Y,Sm){sub 2}O{sub 3} nanoprecipitates, which are self-aligned in planes tilted {approx}7 deg. from the tape plane. Very strong vortex pinning is evidenced by high critical current density J{sub c} values of {approx}3.1 MA cm{sup -2} at 77 K and {approx}43 MA cm{sup -2} at 4.2 K, and by a strongly enhanced irreversibility field H{sub irr}, which reaches that of Nb{sub 3}Sn ({approx}28 T at 1.5 K) at 60 K, even in the inferior direction of H parallel c axis. At 4.2 K, J{sub c} values are {approx}15% of the depairing current density J{sub d}, much the highest of any superconductor suitable for magnet construction.

Transport Properties of the Organic Conductor (TMTSF)2BrO4: Evidence of Variable Range Hopping

DEFF Research Database (Denmark)

Mortensen, Kell; Jacobsen, Claus Schelde; Bechgaard, Klaus

1984-01-01

A study of d.c. and microwave conductivity and thermoelectric power of the organic conductor (TMTSF)2BrO4 is presented. The transport properties are in qualitative agreement with charge transport via variable-range hopping among localized states. The localization is attributed to the anions, which...

Correlation versus surface effects in photoemission of quasi-1D organic conductors

DEFF Research Database (Denmark)

Claessen, R.; Schwingenschlogl, U.; Sing, M.

2002-01-01

The absence of spectral weight at the Fermi level in photoemission spectra of quasi-1D organic conductors has been interpreted as possible evidence for an unusual many-body state. We demonstrate that great care must be exercised to draw this conclusion exclusively on the basis of a pseudogap....... A detailed surface characterization of the charge transfer salts (TMTSF)(2)PFt(6) and TTF-TCNQ shows that signatures of electronic correlations in the valence band spectra are strongly affected by surface effects and may even be completely obscured....

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.

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.

Electronic and magnetic properties of organic conductors (DMET)2MBr4 (M=Fe, Ga)

International Nuclear Information System (INIS)

Enomoto, Kengo; Miyazaki, Akira; Enoki, Toshiaki; Yamaura, Jun-ichi

2003-01-01

(DMET) 2 MBr 4 (M=Fe, Ga) are isostructural organic conductors whose crystal structure consists of an alternate stacking of quasi one-dimensional chain-based donor layers and anion square lattices. The resistivity, ESR, magnetic susceptibility, magnetization, and magnetoresistance of these salts were investigated in order to clarify the correlation between the electronic structure and the magnetism. The electronic structures of both salts are metallic down to T MI - 40 K, below which a Mott insulating state is stabilized, accompanied by an SDW transition at T SDW - 25 K. The FeBr 4 salt with Fe 3+ (S=5/2) localized spins undergoes an antiferromagnetic transition at T N = 3.7 K. In the FeBr 4 salt, the magnetization curves, which show field-direction-dependent anomalies in addition to a spin-flop transition, are demonstrated to have a participation of donor π-electron spins in the magnetization processes. The field dependence of the magnetoresistances below T N tracks faithfully that of the magnetization, where the donor π-electrons and Fe 3+ d-electrons are responsible for the former and the latter, respectively. This clearly demonstrates the presence of the π-d interaction that plays an important role in the interplay between electron transport and magnetism. (author)

Confinement Effects in Low-Dimensional Lead Iodide Perovskite Hybrids

NARCIS (Netherlands)

Kamminga, Machteld E.; Fang, Honghua; Filip, Marina R.; Giustino, Feliciano; Baas, Jacobus; Blake, Graeme R.; Loi, Maria Antonietta; Palstra, Thomas T. M.

2016-01-01

We use a layered solution crystal growth technique to synthesize high-quality single crystals of phenylalkylammonium lead iodide organic/inorganic hybrid compounds. Single-crystal X-ray diffraction reveals low-dimensional structures consisting of inorganic sheets separated by bilayers of the organic

Nonvacuum, maskless fabrication of a flexible metal grid transparent conductor by low-temperature selective laser sintering of nanoparticle ink.

Science.gov (United States)

Hong, Sukjoon; Yeo, Junyeob; Kim, Gunho; Kim, Dongkyu; Lee, Habeom; Kwon, Jinhyeong; Lee, Hyungman; Lee, Phillip; Ko, Seung Hwan

2013-06-25

We introduce a facile approach to fabricate a metallic grid transparent conductor on a flexible substrate using selective laser sintering of metal nanoparticle ink. The metallic grid transparent conductors with high transmittance (>85%) and low sheet resistance (30 Ω/sq) are readily produced on glass and polymer substrates at large scale without any vacuum or high-temperature environment. Being a maskless direct writing method, the shape and the parameters of the grid can be easily changed by CAD data. The resultant metallic grid also showed a superior stability in terms of adhesion and bending. This transparent conductor is further applied to the touch screen panel, and it is confirmed that the final device operates firmly under continuous mechanical stress.

Semi-conducting plastics for disposable electronic devices - What are the organic semi-conductors arriving on the market?; Des plastiques semi-conducteurs pour l'electronique jetable. Qui sont les semi-conducteurs organiques qui arrivent sur le marche?

Energy Technology Data Exchange (ETDEWEB)

Nueesch, F. A. [EMPA, Duebendorf (Switzerland)

2010-07-01

This is a popularization article that describes basic properties of semi-conductors and reports on the status of research and development of organic semi-conductors. In a first part, fundamentals of semi-conductors are recalled. Comparisons are made between inorganic and organic (i.e. based on carbon polymers) compounds. Indications are given on how semi-conducting polymers are obtained. Potential applications are listed: flexible organic solar cells, light emitting diodes, flexible organic displays, intelligent cards for ticketing, etc. Research on organic semi-conductors is of great interest for industry, worldwide, and several companies are widely investing in this area.

Low-dimensional organization of angular momentum during walking on a narrow beam.

Science.gov (United States)

Chiovetto, Enrico; Huber, Meghan E; Sternad, Dagmar; Giese, Martin A

2018-01-08

Walking on a beam is a challenging motor skill that requires the regulation of upright balance and stability. The difficulty in beam walking results from the reduced base of support compared to that afforded by flat ground. One strategy to maintain stability and hence avoid falling off the beam is to rotate the limb segments to control the body's angular momentum. The aim of this study was to examine the coordination of the angular momentum variations during beam walking. We recorded movement kinematics of participants walking on a narrow beam and computed the angular momentum contributions of the body segments with respect to three different axes. Results showed that, despite considerable variability in the movement kinematics, the angular momentum was characterized by a low-dimensional organization based on a small number of segmental coordination patterns. When the angular momentum was computed with respect to the beam axis, the largest fraction of its variation was accounted for by the trunk segment. This simple organization was robust and invariant across all participants. These findings support the hypothesis that control strategies for complex balancing tasks might be easier to understand by investigating angular momentum instead of the segmental kinematics.

Alternating current losses of a 10 metre long low loss superconducting cable conductor determined from phase sensitive measurements

International Nuclear Information System (INIS)

Krueger Olsen, S.; Kuehle, A.; Traeholt, C.; C Rasmussen, C.; Toennesen, O.; Daeumling, M.; Rasmussen, C.N.; Willen, D.W.A.

1999-01-01

The ac loss of a superconducting cable conductor carrying an ac current is small. Therefore the ratio between the inductive (out-of-phase) and the resistive (in-phase) voltages over the conductor is correspondingly high. In vectorial representations this results in phase angles between the current and the voltage over the cable close to 90 degrees. This has the effect that the loss cannot be derived directly using most commercial lock-in amplifiers due to their limited absolute accuracy. However, by using two lock-in amplifiers and an appropriate correction scheme the high relative accuracy of such lock-in amplifiers can be exploited. In this paper we present the results from ac-loss measurements on a low loss 10 metre long high temperature superconducting cable conductor using such a correction scheme. Measurements were carried out with and without a compensation circuit that could reduce the inductive voltage. The 1 μV cm -1 critical current of the conductor was 3240 A at 77 K. At an rms current of 2 kA (50 Hz) the ac loss was derived to be 0.6±0.15 W m -1 . This is, to the best of our knowledge, the lowest value of ac loss of a high temperature superconducting cable conductor reported so far at these high currents. (author)

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

Semiquantum molecular dynamics simulation of thermal properties and heat transport in low-dimensional nanostructures

Science.gov (United States)

Savin, Alexander V.; Kosevich, Yuriy A.; Cantarero, Andres

2012-08-01

We present a detailed description of semiquantum molecular dynamics simulation of stochastic dynamics of a system of interacting particles. Within this approach, the dynamics of the system is described with the use of classical Newtonian equations of motion in which the effects of phonon quantum statistics are introduced through random Langevin-like forces with a specific power spectral density (the color noise). The color noise describes the interaction of the molecular system with the thermostat. We apply this technique to the simulation of thermal properties and heat transport in different low-dimensional nanostructures. We describe the determination of temperature in quantum lattice systems, to which the equipartition limit is not applied. We show that one can determine the temperature of such a system from the measured power spectrum and temperature- and relaxation-rate-independent density of vibrational (phonon) states. We simulate the specific heat and heat transport in carbon nanotubes, as well as the heat transport in molecular nanoribbons with perfect (atomically smooth) and rough (porous) edges, and in nanoribbons with strongly anharmonic periodic interatomic potentials. We show that the effects of quantum statistics of phonons are essential for the carbon nanotube in the whole temperature range T<500K, in which the values of the specific heat and thermal conductivity of the nanotube are considerably less than that obtained within the description based on classical statistics of phonons. This conclusion is also applicable to other carbon-based materials and systems with high Debye temperature like graphene, graphene nanoribbons, fullerene, diamond, diamond nanowires, etc. We show that the existence of rough edges and quantum statistics of phonons change drastically the low-temperature thermal conductivity of the nanoribbon in comparison with that of the nanoribbon with perfect edges and classical phonon dynamics and statistics. The semiquantum molecular

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....

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

Advanced electron holography techniques for in situ observation of solid-state lithium ion conductors

Energy Technology Data Exchange (ETDEWEB)

Hirayama, Tsukasa, E-mail: t-hirayama@jfcc.or.jp [Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya, Aichi 456-8587 (Japan); Aizawa, Yuka; Yamamoto, Kazuo; Sato, Takeshi [Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya, Aichi 456-8587 (Japan); Murata, Hidekazu [Faculty of Science and Technology, Meijo University, 1-501 Shiogamaguchi, Tempaku-ku, Nagoya, Aichi 468-8502 (Japan); Yoshida, Ryuji; Fisher, Craig A.J. [Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya, Aichi 456-8587 (Japan); Kato, Takehisa; Iriyama, Yasutoshi [Department of Materials, Physics and Energy Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601 (Japan)

2017-05-15

Advanced techniques for overcoming problems encountered during in situ electron holography experiments in which a voltage is applied to an ionic conductor are reported. The three major problems encountered were 1) electric-field leakage from the specimen and its effect on phase images, 2) high electron conductivity of damage layers formed by the focused ion beam method, and 3) chemical reaction of the specimen with air. The first problem was overcome by comparing experimental phase distributions with simulated images in which three-dimensional leakage fields were taken into account, the second by removing the damage layers using a low-energy narrow Ar ion beam, and the third by developing an air-tight biasing specimen holder. - Highlights: • Phase distributions derived by comparing experimental and simulated measurements. • Simulations take into account leakage electric fields. • Electric potential distributions inside Li-ion conductors are obtained. • FIB damage layers are removed using a low-energy narrow Ar ion beam. • An air-tight biasing TEM holder for protecting air-sensitive specimens is reported.

Synthesis of POSS-based ionic conductors with low glass transition temperatures for efficient solid-state dye-sensitized solar cells.

Science.gov (United States)

Zhang, Wei; Wang, Zhong-Sheng

2014-07-09

Replacing liquid-state electrolytes with solid-state electrolytes has been proven to be an effective way to improve the durability of dye-sensitized solar cells (DSSCs). We report herein the synthesis of amorphous ionic conductors based on polyhedral oligomeric silsesquioxane (POSS) with low glass transition temperatures for solid-state DSSCs. As the ionic conductor is amorphous and in the elastomeric state at the operating temperature of DSSCs, good pore filling in the TiO2 film and good interfacial contact between the solid-state electrolyte and the TiO2 film can be guaranteed. When the POSS-based ionic conductor containing an allyl group is doped with only iodine as the solid-state electrolyte without any other additives, power conversion efficiency of 6.29% has been achieved with good long-term stability under one-sun soaking for 1000 h.

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...

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...

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

Low-Cost Manufacturing of Bioresorbable Conductors by Evaporation-Condensation-Mediated Laser Printing and Sintering of Zn Nanoparticles.

Science.gov (United States)

Shou, Wan; Mahajan, Bikram K; Ludwig, Brandon; Yu, Xiaowei; Staggs, Joshua; Huang, Xian; Pan, Heng

2017-07-01

Currently, bioresorbable electronic devices are predominantly fabricated by complex and expensive vacuum-based integrated circuit (IC) processes. Here, a low-cost manufacturing approach for bioresorbable conductors on bioresorbable polymer substrates by evaporation-condensation-mediated laser printing and sintering of Zn nanoparticle is reported. Laser sintering of Zn nanoparticles has been technically difficult due to the surface oxide on nanoparticles. To circumvent the surface oxide, a novel approach is discovered to print and sinter Zn nanoparticle facilitated by evaporation-condensation in confined domains. The printing process can be performed on low-temperature substrates in ambient environment allowing easy integration on a roll-to-roll platform for economical manufacturing of bioresorbable electronics. The fabricated Zn conductors show excellent electrical conductivity (≈1.124 × 10 6 S m -1 ), mechanical durability, and water dissolvability. Successful demonstration of strain gauges confirms the potential application in various environmentally friendly sensors and circuits. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

Thermo-Hydraulic behaviour of dual-channel superconducting Cable-In-Conduit Conductors for ITER

International Nuclear Information System (INIS)

Renard, B.

2006-09-01

In an effort to optimise the cryogenics of large superconducting coils for fusion applications (ITER), dual channel Cable-In-Conduit Conductors (CICC) are designed with a central channel spiral to provide low hydraulic resistance and faster helium circulation. The qualitative and economic rationale of the conductor central channel is here justified to limit the superconductor temperature increase, but brings more complexity to the conductor cooling characteristics. The pressure drop of spirals is experimentally evaluated in nitrogen and water and an explicit hydraulic friction model is proposed. Temperatures in the cable must be quantified to guarantee superconductor margin during coil operation under heat disturbance and set adequate inlet temperature. Analytical one-dimensional thermal models, in steady state and in transient, allow to better understand the thermal coupling of CICC central and annular channels. The measurement of a heat transfer characteristic space and time constants provides cross-checking experimental estimations of the internal thermal homogenization. A simple explicit model of global inter-channel heat exchange coefficient is proposed. The risk of thermosyphon between the two channels is considered since vertical portions of fusion coils are subject to gravity. The new hydraulic model, heat exchange model and gravitational risk ratio allow the thermohydraulic improvement of CICC central spirals. (author)

Spin-polarized currents in the tunnel contact of a normal conductor and a two-dimensional topological insulator

International Nuclear Information System (INIS)

Sukhanov, A. A.; Sablikov, V. A.

2013-01-01

The spin filtering of electrons tunneling from the edge states of a two-dimensional topological insulator into a normal conductor under a magnetic field (external or induced due to proximity to a magnetic insulator) is studied. Calculations are performed for a tunnel contact of finite length between the topological insulator and an electronic multimode quantum strip. It is shown that the flow of tunneling electrons is split in the strip, so that spin-polarized currents arise in its left and right branches. These currents can be effectively controlled by the contact voltage and the chemical potential of the system. The presence of a magnetic field, which splits the spin subbands of the electron spectrum in the strip, gives rise to switching of the spin current between the strip branches

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.

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.

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

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.''

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....

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.

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.

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

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.

Model for electromagnetic field analysis of superconducting power transmission cable comprising spiraled coated conductors

International Nuclear Information System (INIS)

Takeuchi, Katsutoku; Amemiya, Naoyuki; Nakamura, Taketsune; Maruyama, Osamu; Ohkuma, Takeshi

2011-01-01

Since the superconductor layers of YBCO-coated conductors are very thin, the ac loss of coated conductors is dominated by the magnetic flux density normal to the conductor face. In cables, most of the normal magnetic flux component is generated near gaps between coated conductors. Although the effects of gaps are significant, there are few reports on the electromagnetic field analysis of cables with spiral structures carried out while taking the gap effect into consideration. In a finitely long cable with a spiral structure, the electromagnetic field is naturally periodic along the cable axis. In a two-layer cable, the simplest period along the cable axis is the least common multiple of the spiral pitches in the inner and outer layers. However, we verified that there is a shorter period, and the same electromagnetic field distribution appears in all conductors of the same layer. Using these periodicities, we developed a three-dimensional model for the analysis of two-layer cables with a spiral structure. Current distributions of cables were analyzed using this model, and ac losses were calculated. In addition, these results were compared with ac losses calculated by two-dimensional analysis performed on the cross section of a cable. It was verified that the ac loss in a cable is correctly calculated by the 2D model when the spiral pitch is long enough. However, in the case of a tightly twisted cable, the ac losses calculated by the 2D model include some errors caused by an approximation in which the spiral structure is ignored.

Organic Conductors

DEFF Research Database (Denmark)

Andersen, Jan Rud; Jacobsen, Claus S.; Rindorf, Grethe

1975-01-01

2,3,6,7-Tetramethyl-1,4,5,8-tetraselenafulvalene reacts with 2,5-dimethyl-7,7′,8,8′-tetracyano-p-quinodi-methane to give a highly conducting organic solid.......2,3,6,7-Tetramethyl-1,4,5,8-tetraselenafulvalene reacts with 2,5-dimethyl-7,7′,8,8′-tetracyano-p-quinodi-methane to give a highly conducting organic solid....

Low dimensional temporal organization of spontaneous eye blinks in adults with developmental disabilities and stereotyped movement disorder.

Science.gov (United States)

Lee, Mei-Hua; Bodfish, James W; Lewis, Mark H; Newell, Karl M

2010-01-01

This study investigated the mean rate and time-dependent sequential organization of spontaneous eye blinks in adults with intellectual and developmental disability (IDD) and individuals from this group who were additionally categorized with stereotypic movement disorder (IDD+SMD). The mean blink rate was lower in the IDD+SMD group than the IDD group and both of these groups had a lower blink rate than a contrast group of healthy adults. In the IDD group the n to n+1 sequential organization over time of the eye-blink durations showed a stronger compensatory organization than the contrast group suggesting decreased complexity/dimensionality of eye-blink behavior. Very low blink rate (and thus insufficient time series data) precluded analysis of time-dependent sequential properties in the IDD+SMD group. These findings support the hypothesis that both IDD and SMD are associated with a reduction in the dimension and adaptability of movement behavior and that this may serve as a risk factor for the expression of abnormal movements.

Solid state protonic conductors II for fuel cells and sensors. Proceedings of the European workshop on solid state materials for low to medium temperature fuel cells and monitors, with special emphasis on proton conductors

Energy Technology Data Exchange (ETDEWEB)

Goodenough, J B; Jensen, J; Kleitz, M [eds.

1983-01-01

Solid electrolytes for chemical sensing, energy storage and conversion have been actively researched and developed since the early sixties. The zirconia fuel-cell electrolyser, the sodium-sulphur rechargeable battery, the oxygen sensor and lithium batteries can all be cited as significant developments from the field. Although of great potential the solid protonic conductors have somehow been ignored by comparison to the great interest that has been shown in, e.g., the lithium conductors. The long absence of any good, stable protonic conductors could easily explain this. The presence of water in the protonic conductors eliminates the possibility of high-temperature preparation and hence of conventional ceramic processing. Since solid electrolytes are used as dense ceramic membranes, difficulties with the fabrication of protonic electrilytes has been a strong disincentive. However, techniques have been developed for fabricating dense composite membranes; these contain free, but immobilized water that is lost at relatively low temperatures. Framework hydrates hold their water to higher temperatures. Although low-temperature ion-exchange preparations are possible, they yield weak ceramics. Nevertheless, their support on strong substrates, as reported in this conference, may provide an alternate way forward. A second workshop was organised on this theme at Hindsgavl Castle, Denmark, 1982. The aim was to compare the progress made in laboratories in Denmark, France and U.K. and also to review present and and future applications of fuel cells in a broader sense. Thirty scientists and representatives from the Commission of the European Communities, European Space Agency and the Daish Ministry of Energy participated. The proceedings cover all the papers of the workshop and the main comments and suggestions proposed during the discussions.

Design of transparent conductors and periodic two-dimensional electron gases without doping

Science.gov (United States)

Zhang, Xiuwen; Zhang, Lijun; Zunger, Alex; Perkins, John; Materials by Design Team; John D. Perkins Collaboration

The functionality of transparency plus conductivity plays an important role in renewable energy and information technologies, including applications such as solar cells, touch-screen sensors, and flat panel display. However, materials with such seemingly contraindicated properties are difficult to come by. The traditional strategy for designing bulk transparent conductors (TCs) starts from a wide-gap insulator and finds ways to make it conductive by extensive doping. We propose a different strategy for TC design--starting with a metallic conductor and designing transparency by control of intrinsic interband transitions and intraband plasmonic frequency. We identified specific design principles for prototypical intrinsic TC classes and searched computationally for materials that satisfy them. The electron gases in the 3D intrinsic TCs demonstrate intriguing properties, such as periodic 2D electron gas regions with very high carrier density. We will discuss a more extended search of these functionalities, in parallel with stability and growability calculations

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.

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.

Fermi surface studies of low-dimensional organic conductors based on BEDT-TTF

International Nuclear Information System (INIS)

Singleton, John; Caulfield, Jason; Hill, Stephen; Blundell, Stephen; Lubczynski, Wieslaw; House, Andrew; Hayes, William; Perenboom, Jos; Kurmoo, Mohammedally; Day, Peter

1995-01-01

This paper provides an introduction to charge-transfer salts of the ion bis(ethylenedithio)tetrathiafulvalene (ET) and their band-structure, and reviews some recent experiments on the salts involving high magnetic fields carried out by the Oxford group and coworkers. (orig.)

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.

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)

Prosthetic avian vocal organ controlled by a freely behaving bird based on a low dimensional model of the biomechanical periphery.

Directory of Open Access Journals (Sweden)

Ezequiel M Arneodo

Full Text Available Because of the parallels found with human language production and acquisition, birdsong is an ideal animal model to study general mechanisms underlying complex, learned motor behavior. The rich and diverse vocalizations of songbirds emerge as a result of the interaction between a pattern generator in the brain and a highly nontrivial nonlinear periphery. Much of the complexity of this vocal behavior has been understood by studying the physics of the avian vocal organ, particularly the syrinx. A mathematical model describing the complex periphery as a nonlinear dynamical system leads to the conclusion that nontrivial behavior emerges even when the organ is commanded by simple motor instructions: smooth paths in a low dimensional parameter space. An analysis of the model provides insight into which parameters are responsible for generating a rich variety of diverse vocalizations, and what the physiological meaning of these parameters is. By recording the physiological motor instructions elicited by a spontaneously singing muted bird and computing the model on a Digital Signal Processor in real-time, we produce realistic synthetic vocalizations that replace the bird's own auditory feedback. In this way, we build a bio-prosthetic avian vocal organ driven by a freely behaving bird via its physiologically coded motor commands. Since it is based on a low-dimensional nonlinear mathematical model of the peripheral effector, the emulation of the motor behavior requires light computation, in such a way that our bio-prosthetic device can be implemented on a portable platform.

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.

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

Enhancing Light-Trapping Properties of Amorphous Si Thin-Film Solar Cells Containing High-Reflective Silver Conductors Fabricated Using a Nonvacuum Process

Directory of Open Access Journals (Sweden)

Jun-Chin Liu

2014-01-01

Full Text Available We proposed a low-cost and highly reflective liquid organic sheet silver conductor using back contact reflectors in amorphous silicon (a-Si single junction superstrate configuration thin-film solar cells produced using a nonvacuum screen printing process. A comparison of silver conductor samples with vacuum-system-sputtered silver samples indicated that the short-circuit current density (Jsc of sheet silver conductor cells was higher than 1.25 mA/cm2. Using external quantum efficiency measurements, the sheet silver conductor using back contact reflectors in cells was observed to effectively enhance the light-trapping ability in a long wavelength region (between 600 nm and 800 nm. Consequently, we achieved an optimal initial active area efficiency and module conversion efficiency of 9.02% and 6.55%, respectively, for the a-Si solar cells. The results indicated that the highly reflective sheet silver conductor back contact reflector layer prepared using a nonvacuum process is a suitable candidate for high-performance a-Si thin-film solar cells.

On the electrical contact and long-term behavior of compression-type connections with conventional and high-temperature conductor ropes with low sag

International Nuclear Information System (INIS)

Hildmann, Christian

2016-01-01

In Germany and in Europe it is due to the ''Energiewende'' necessary to transmit more electrical energy with existing overhead transmission lines. One possible technical solution to reach this aim is the use of high temperature low sag conductors (HTLS-conductors). Compared to the common Aluminium Conductor Steel Reinforced (ACSR), HTLS-conductors have higher rated currents and rated temperatures. Thus the electrical connections for HTLS-conductors are stressed to higher temperatures too. These components are most important for the safe and reliable operation of an overhead transmission line. Besides other connection technologies, hexagonal compression connections with ordinary transmission line conductors have proven themselves since decades. From the literature, mostly empirical studies with electrical tests for compression connections are known. The electrical contact behaviour, i.e. the quality of the electrical contact after assembly, of these connections has been investigated insufficiently. This work presents and enhances an electrical model of compression connections, so that the electrical contact behaviour can be determined more accurate. Based on this, principal considerations on the current distribution in the compression connection and its influence on the connection resistance are presented. As a result from the theoretical and the experimental work, recommendations for the design of hexagonal compression connections for transmission line conductors were developed. Furthermore it is known from the functional principle of compression type connections, that the electrical contact behaviour can be influenced from their form fit, force fit and cold welding. In particular the forces in compression connections have been calculated up to now by approximation. The known analytical calculations simplify the geometry and material behaviour and do not consider the correct mechanical load during assembly. For these reasons the joining process

Low-dimensional molecular metals

CERN Document Server

Toyota, Naoki; Muller, Jens

2007-01-01

Assimilating research in the field of low-dimensional metals, this monograph provides an overview of the status of research on quasi-one- and two-dimensional molecular metals, describing normal-state properties, magnetic field effects, superconductivity, and the phenomena of interacting p and d electrons.

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

Importance of low-angle grain boundaries in YBa2Cu3O7-δ coated conductors

International Nuclear Information System (INIS)

Durrell, J H; Rutter, N A

2009-01-01

Over the past ten years the perception of grain boundaries in YBa 2 Cu 3 O 7-δ conductors has changed greatly. They are now not a problem to be eliminated, but an inevitable and potentially favourable part of the material. This change has arisen as a consequence of new manufacturing techniques which result in excellent grain alignment, reducing the spread of grain boundary misorientation angles. At the same time there is considerable recent evidence which indicates that the variation of properties of grain boundaries with mismatch angle is more complex than a simple exponential decrease in critical current. This is due to the fact that low-angle grain boundaries represent a qualitatively different system to high-angle boundaries. The time is therefore right for a targeted review of research into low-angle YBa 2 Cu 3 O 7-δ grain boundaries. This article does not purport to be a comprehensive review of the physics of grain boundaries as found in YBa 2 Cu 3 O 7-δ in general; for a broader overview we would recommend that the reader consult the comprehensive review of Hilgenkamp and Mannhart (2002 Rev. Mod. Phys. 74 485). The purpose of this article is to review the origin and properties of the low-angle grain boundaries found in YBa 2 Cu 3 O 7-δ coated conductors both individually and as a collective system. (topical review)

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.

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)

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

Low-dimensionality and predictability of solar wind and global magnetosphere during magnetic storms

OpenAIRE

Zivkovic, Tatjana; Rypdal, Kristoffer

2011-01-01

This article is part of Tatjana Živkovics' doctoral thesis. Available in Munin at http://hdl.handle.net/10037/3231 The storm index SYM-H, the solar wind velocity v, and interplanetary magnetic field Bz show no signatures of low-dimensional dynamics in quiet periods, but tests for determinism in the time series indicate that SYM-H exhibits a significant low-dimensional component during storm time, suggesting that self-organization takes place during magnetic storms. Even though our analysis...

Broad Temperature Pinning Study of 15 mol.% Zr-Added (Gd, Y)-Ba-Cu-O MOCVD Coated Conductors

Energy Technology Data Exchange (ETDEWEB)

Xu, AX; Khatri, N; Liu, YH; Majkic, G; Galstyan, E; Selvamanickam, V; Chen, YM; Lei, CH; Abraimov, D; Hu, XB; Jaroszynski, J; Larbalestier, D

2015-06-01

BaZrO3 (BZO) nanocolumns have long been shown to be very effective for raising the pinning force F-p of REBa2Cu3Ox (REBCO, where RE = rare earth) films at high temperatures and recently at low temperatures too. We have successfully incorporated a high density of BZO nanorods into metal organic chemical vapor deposited (MOCVD) REBCO coated conductors via Zr addition. We found that, compared to the 7.5% Zr-added coated conductor, dense BZO nanorod arrays in the 15% Zr-added conductor are effective over the whole temperature range from 77 K down to 4.2 K. We attribute the substantially enhanced J(c) at 30 K to the weak uncorrelated pinning as well as the strong correlated pinning. Meanwhile, by tripling the REBCO layer thickness to similar to 2.8 mu m, the engineering critical current density J(e) at 30 K exceeds J(e) of optimized Nb-Ti wires at 4.2 K.

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

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

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.

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...

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...

Dynamic colloidal assembly pathways via low dimensional models

Energy Technology Data Exchange (ETDEWEB)

Yang, Yuguang; Bevan, Michael A., E-mail: mabevan@jhu.edu [Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Thyagarajan, Raghuram; Ford, David M. [Chemical Engineering, University of Massachusetts, Amherst, Massachusetts 01003 (United States)

2016-05-28

Here we construct a low-dimensional Smoluchowski model for electric field mediated colloidal crystallization using Brownian dynamic simulations, which were previously matched to experiments. Diffusion mapping is used to infer dimensionality and confirm the use of two order parameters, one for degree of condensation and one for global crystallinity. Free energy and diffusivity landscapes are obtained as the coefficients of a low-dimensional Smoluchowski equation to capture the thermodynamics and kinetics of microstructure evolution. The resulting low-dimensional model quantitatively captures the dynamics of different assembly pathways between fluid, polycrystal, and single crystals states, in agreement with the full N-dimensional data as characterized by first passage time distributions. Numerical solution of the low-dimensional Smoluchowski equation reveals statistical properties of the dynamic evolution of states vs. applied field amplitude and system size. The low-dimensional Smoluchowski equation and associated landscapes calculated here can serve as models for predictive control of electric field mediated assembly of colloidal ensembles into two-dimensional crystalline objects.

Raman Spectroscopic Studies of YBa{sub 2}Cu{sub 3}O{sub 7} Coated Conductors

Energy Technology Data Exchange (ETDEWEB)

Choi, Mi Kyeung; Mnh, Nguyen Van; Bae, J. S.; Jo, William; Yang, In Sang [Ewha Womans University, Seoul (Korea, Republic of); Ko, Rock Kil; Ha, Hong Soo; Park, Chan [Korea Electrotecnology Research Institute, Changwon (Korea, Republic of)

2005-04-15

We present results of Raman spectroscopic studies of superconducting YBa{sub 2}Cu{sub 3}O{sub 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.

Exciton Migration and Amplified Quenching on Two-Dimensional Metal–Organic Layers

Energy Technology Data Exchange (ETDEWEB)

Cao, Lingyun; Lin, Zekai; Shi, Wenjie; Wang, Zi; Zhang, Cankun; Hu, Xuefu; Wang, Cheng; Lin, Wenbin (UC); (Xiamen)

2017-05-10

The dimensionality dependency of resonance energy transfer is of great interest due to its importance in understanding energy transfer on cell membranes and in low-dimension nanostructures. Light harvesting two-dimensional metal–organic layers (2D-MOLs) and three-dimensional metal–organic frameworks (3D-MOFs) provide comparative models to study such dimensionality dependence with molecular accuracy. Here we report the construction of 2D-MOLs and 3D-MOFs from a donor ligand 4,4',4''-(benzene-1,3,5-triyl-tris(ethyne-2,1-diyl))tribenzoate (BTE) and a doped acceptor ligand 3,3',3''-nitro-4,4',4''-(benzene-1,3,5-triyl-tris(ethyne-2,1-diyl))tribenzoate (BTE-NO2). These 2D-MOLs and 3D-MOFs are connected by similar hafnium clusters, with key differences in the topology and dimensionality of the metal–ligand connection. Energy transfer from donors to acceptors through the 2D-MOL or 3D-MOF skeletons is revealed by measuring and modeling the fluorescence quenching of the donors. We found that energy transfer in 3D-MOFs is more efficient than that in 2D-MOLs, but excitons on 2D-MOLs are more accessible to external quenchers as compared with those in 3D-MOFs. These results not only provide support to theoretical analysis of energy transfer in low dimensions, but also present opportunities to use efficient exciton migration in 2D materials for light-harvesting and fluorescence sensing.

Polymer-assisted metal deposition (PAMD): a full-solution strategy for flexible, stretchable, compressible, and wearable metal conductors.

Science.gov (United States)

Yu, You; Yan, Casey; Zheng, Zijian

2014-08-20

Metal interconnects, contacts, and electrodes are indispensable elements for most applications of flexible, stretchable, and wearable electronics. Current fabrication methods for these metal conductors are mainly based on conventional microfabrication procedures that have been migrated from Si semiconductor industries, which face significant challenges for organic-based compliant substrates. This Research News highlights a recently developed full-solution processing strategy, polymer-assisted metal deposition (PAMD), which is particularly suitable for the roll-to-roll, low-cost fabrication of high-performance compliant metal conductors (Cu, Ni, Ag, and Au) on a wide variety of organic substrates including plastics, elastomers, papers, and textiles. This paper presents i) the principles of PAMD, and how to use it for making ii) flexible, stretchable, and wearable conductive metal electrodes, iii) patterned metal interconnects, and d) 3D stretchable and compressible metal sponges. A critical perspective on this emerging strategy is also provided. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structure engineering of hole-conductor free perovskite-based solar cells with low-temperature-processed commercial carbon paste as cathode.

Science.gov (United States)

Zhang, Fuguo; Yang, Xichuan; Wang, Haoxin; Cheng, Ming; Zhao, Jianghua; Sun, Licheng

2014-09-24

Low-temperature-processed (100 °C) carbon paste was developed as counter electrode material in hole-conductor free perovskite/TiO2 heterojunction solar cells to substitute noble metallic materials. Under optimized conditions, an impressive PCE value of 8.31% has been achieved with this carbon counter electrode fabricated by doctor-blading technique. Electrochemical impedance spectroscopy demonstrates good charge transport characteristics of low-temperature-processed carbon counter electrode. Moreover, this carbon counter electrode-based perovskite solar cell exhibits good stability over 800 h.

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.

Two-dimensional conductors with interactions and disorder from particle-vortex duality

Science.gov (United States)

Goldman, H.; Mulligan, M.; Raghu, S.; Torroba, G.; Zimet, M.

2017-12-01

We study Dirac fermions in two spatial dimensions (2D) coupled to strongly fluctuating U (1 ) gauge fields in the presence of quenched disorder. Such systems are dual to theories of free Dirac fermions, which are vortices of the original theory. In analogy to superconductivity, when these fermionic vortices localize, the original system becomes a perfect conductor, and when the vortices possess a finite conductivity, the original fermions do as well. We provide several realizations of this principle and thereby introduce examples of strongly interacting 2D metals that evade Anderson localization.

Magnetic field influence on the spin-density wave of the organic conductor (TMTSF)2NO3

International Nuclear Information System (INIS)

Tomic, S.; Biskup, N.; Korin-Hamzic, B.; Basletic, M.; Hamzic, A.; Maki, K.; Fabre, J.M.; Bechgaard, K.

1993-01-01

We present the influence of a transverse magnetic field on the spin-density wave (SDW) ground state of the organic conductor (TMTSF) 2 NO 3 . Magnetic field increases the single-particle activation energy. A finite magnetic field (H C ) induces discontinuities in the magnetoresistance behaviour and its value is temperature dependent. The threshold electric field (E T ) for the SDW sliding increases in a magnetic field. All observed effects are strongly angle-dependent indicating that they are determined by the magnetic field component along the least-conduction (c * ) direction. We discuss these results in the framework of a theoretical model for the SDW with large imperfect nesting. (orig.)

Review on Material Synthesis and Characterization of Sodium (Na) Super-Ionic Conductor (NASICON)

Science.gov (United States)

Kimpa, M. I.; Mayzan, M. Z. H.; Yabagi, J. A.; Nmaya, M. M.; Isah, K. U.; Agam, M. A.

2018-04-01

Sodium (Na) Super Ionic Conductor (NASICON) has general formula Na1+ x Zr2P3- xSi x O12 (0 ≤x ≤ 3) derived from its parent compound, sodium zirconium phosphate NaZr2(PO4)3 (NZP) which belong to a rhombohedral crystal structure. This material consists of three-dimensional structure with interesting features such as low thermal expansion coefficient, thermal stability, gas sensor and nuclear waste immobilization that make it viable for industrial applications. Current study presents comprehensive studies on the synthesis and essential characteristics required to understand the theory behind the mechanism that justifies the study of NASICON structure and its application such as lithium ion rechargeable battery, gas sensor, and nuclear waste immobilization and so on.

Revealing origin of quasi-one dimensional current transport in defect rich two dimensional materials

DEFF Research Database (Denmark)

Lotz, Mikkel Rønne; Boll, Mads; Hansen, Ole

2014-01-01

to a non-uniform current flow characteristic of lower dimensionality. In this work, simulations based on a finite element method together with a Monte Carlo approach are used to establish the transition from 2D to quasi-1D current transport, when applying a micro four-point probe to measure on 2D...... conductors with an increasing amount of line-shaped defects. Clear 2D and 1D signatures are observed at low and high defect densities, respectively, and current density plots reveal the presence of current channels or branches in defect configurations yielding 1D current transport. A strong correlation...

Hall effect in the normal phase of the organic superconductor (TMTSF)2PF6

DEFF Research Database (Denmark)

Moser, J.; Cooper, J.R.; Jerome, D.

2000-01-01

We report accurate Hall effect measurements performed in the normal phase of the quasi-one-dimensional organic conductor (TMTSF)(2)PF(6) at ambient pressure. The Hall coefficient is found to be strongly temperature dependent all the way from 300 K down to the spin density wave onset arising aroun...

A High Current Density Low Cost Niobium 3 Tin Titanium Doped Conductor Utilizing A Novel Internal Tin Process

International Nuclear Information System (INIS)

Bruce A Zeitlin

2005-01-01

An internal tin conductor has been developed using a Mono Element Internal Tin (MEIT) with an integral Nb barrier surrounding the Nb filaments. High current densities of 3000 A/mm2+ at 12 T and 1800 A/mm2 at 15 T have been achieved in conductors as small as 0.152 mm with the use of Nb7.5Ta filaments and Ti in the Sn core. In contrast, conductors with pure Nb and Ti in the Sn achieved 2700 A/mm2 at 12 T. Two internal fins, developed and patented on the project, were introduced into the filament array and reduced the effective filament diameter (Deff) by 38%. Additional fins will further reduce Deff The conductor was produced from 152.4 mm diameter billets to produce wire as small as 0.152 mm. The process promises be scaleable to 304 mm diameter billets yielding wire of 0.304 mm diameter. The MEIT process wire was easy to draw with relatively few breaks. The cost of this conductor in large production quantities based on the cost model presented could meet the 1.5 $/kilo amp meter(KAM) target of the HEP community

Low-dimensional model of resistive interchange convection in magnetized plasma

International Nuclear Information System (INIS)

Bazdenkov, S.; Sato, Tetsuya

1997-09-01

Self-organization and generation of large shear flow component in turbulent resistive interchange convection in magnetized plasma is considered. The effect of plasma density-electrostatic potential coupling via the inertialess electron dynamics along the magnetic field is shown to play significant role in the onset of shear component. The results of large-scale numerical simulation and low-dimensional (reduced) model are presented and compared. (author)

Irradiation effects and the role of disorder in low dimensional conductors

International Nuclear Information System (INIS)

Zuppiroli, L.; Mutka, H.; Bouffard, S.

1981-08-01

The concentration of defects produced by irradiation can be measured by several independent methods such as longitudinal and transverse conductivity measurements at room temperature, spin susceptibility at low temperature, volume or lattice parameters change. The physical consequences of this kind of disorder are as follows. The superconductivy in (TMTSF) 2 PF 6 is destroyed by a molecular concentration of 10-4. The concentration of 2.10 -3 corresponds to the full pinning of charge density waves in monoclinic TaS 3 , 1T-TaS 2 , TTF-TCNQ, TMTSF-DMTCNQ ... Microdiffraction experiments demonstrate some structural aspects of this pinning and conductivity, Hall effect and thermoelectric power measurements demonstrate the consequence of the pinning on the electronic properties of several low temperature charge density wave insulators. In most of the cases the metallic state is stabilized by a weak disorder. The problem of the charge density wave motion in presence of defects is discussed in connection with the electric field depinning experiments. Concentrations of the order of 10 -2 or more correspond to a concentration range of localization by disorder

A new kind of low-inductance transformer type magnetic switch (TTMS) with coaxial cylindrical conductors.

Science.gov (United States)

Zhang, Yu; Liu, Jinliang

2013-02-01

As important devices for voltage boosting and switching, respectively, pulse transformer and magnetic switch are widely used in pulsed power technology. In this paper, a new kind of transformer type magnetic switch (TTMS) with coaxial cylindrical conductors is put forward to combine the functions of voltage boosting and switching in one power device. As a compact combination device of discrete pulse transformer and magnetic switch, the compact TTMS decreases the required volume of magnetic cores in a large scale. The primary windings of the TTMS have a parallel combination structure so that the TTMS which only has 3 turns of secondary windings has a step-up ratio at 1:9. Before the magnetic core saturates, the TTMS has low unsaturated inductances of windings and good pulse response characteristics, so it can be used to substitute the Marx generator to charge the pulse forming line (PFL) at the ranges of several hundred kV and several hundred ns. After the core saturates, the cylindrical conductors can decrease the saturated inductance of the secondary windings of TTMS to a level less than 400 nH. As a result, the proposed TTMS can be used as the boosting transformer and main switch of helical Blumlein PFL to form the quasi-square voltage pulse on the 160 Ω load with a short pulse rise time only at 60 ns.

Distribución de potencia en los alimentadores de baja tensión con varios conductores por fase; Power Distribution in Low Tension Feeders with Several Phase Conductors

Directory of Open Access Journals (Sweden)

Héctor S Llamo Laborí

2011-02-01

Full Text Available En las redes de distribución a 120/208 V, las corrientes debidas a las cargas son muy altas y ello obliga ainstalar varios conductores en paralelo por fase. La mayor o menor asimetría de las corrientes que circulan porcada uno de los conductores que forman cada fase no son función del balanceo que se haga de la carga ni delmayor o menor desbalance de las tensiones sino de la disposición de las fases. En este trabajo se presentanlas características y los resultados de un algoritmo para determinar cuál es la disposición de las fases quepermiten obtener el mejor aprovechamiento de la capacidad instalada en los conductores del alimentador. In the 120/208 distribution grids, the loads currents are very high. In this case it is necessary to install severalconductors in parallel. The more o less asymmetry of currents in the different conductors that form everyphase is function of the phase disposition and not of the more or less unbalance of the tension or the loadscurrents. In this work are presented the characteristics and the results of algorithms that permit to determinewhich the phase disposition is that bring the better use of the installed capacity of the feeder.

Basic physics of one-dimensional metals

International Nuclear Information System (INIS)

Emery, V.J.

1976-01-01

Largely nonmathematical qualitative lectures are given on the basic physics of nearly one-dimensional conductors. The main emphasis is placed on the properties of a purely one-dimensional electron gas. The effects of a real system having interchain coupling, impurities, a compressible lattice, lattice distortions and phonon anomalies are discussed

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.

Simulating Photons and Plasmons in a Three-dimensional Lattice

International Nuclear Information System (INIS)

Pletzer, A.; Shvets, G.

2002-01-01

Three-dimensional metallic photonic structures are studied using a newly developed mixed finite element-finite difference (FE-FD) code, Curly3d. The code solves the vector Helmholtz equation as an eigenvalue problem in the unit cell of a triply periodic lattice composed of conductors and/or dielectrics. The mixed FE-FD discretization scheme ensures rapid numerical convergence of the eigenvalue and allows the code to run at low resolution. Plasmon and photonic band structure calculations are presented

Magnetic losses of commercial REBCO coated conductors in the low frequency range

Science.gov (United States)

De Marzi, G.; Iannone, G.; Gambardella, U.

2018-05-01

We have investigated the frequency dependence of the magnetic losses of different 2 G commercial REBCO coated-conductor tapes in the low frequency range ∼1–10 mHz of applied magnetic field at 5 and 77 K. We explored high field range, well above the penetration field, with fields applied perpendicularly to the flat surface. We found that the in-field hysteresis losses increase with increasing frequencies in all the investigated high-temperature superconductor (HTS) tapes, following a power-law dependence. An electromagnetic 2D finite element method model, based on H-formulation, has also been implemented, in which the frequency dependence of the hysteretic loss is computed taking into account the measured power-law E(J) characteristic for the electric field, and the experimental J c(B). Experimental and numerical findings are in very good agreement, so an extrapolation to higher ramp rate values is possible, thus providing a useful basis for the assessment of the hysteresis losses in fusion and accelerator HTS magnets.

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.

Quantum Fluctuations of Low Dimensional Bose-Einstein ...

African Journals Online (AJOL)

A system of low dimensional condensed ultracold atomic gases inside a field of a laser-driven optical cavity exhibits dispersive optical bistability. During such a process the system also shows quantum fluctuations. Condensate fluctuations are highly manifested particularly in low dimensional systems. In this paper we have ...

Temperature dependence of critical current and transport current losses of 4 mm YBCO coated conductors manufactured using nonmagnetic substrate

Science.gov (United States)

Kvitkovic, J.; Hatwar, R.; Pamidi, S. V.; Fleshler, S.; Thieme, C.

2015-12-01

The temperature dependence of the critical current and AC losses were measured on American Superconductor Corporation's (AMSC) second generation high temperature superconducting (2G HTS) wire produced by Rolling Assisted Biaxially Textured Substrate (RABiTS) and Metal Organic Deposition (MOD) process. Wires manufactured with two types of substrates were characterized. The magnetic substrate with composition Ni5a%W exhibits a magnetic signature and has non-negligible AC losses in AC power applications. A new nonmagnetic substrate with an alloy composition Ni9a%W has been developed by AMSC to address the AC losses in 2G HTS. The data presented show that the performance of the new conductor is identical to the conductor with magnetic substrate in terms of critical current density. The data on AC losses demonstrate the absence of ferromagnetic loss component in the new conductor and significantly reduced AC losses at low to moderate values of I/Ic. The reduced losses will translate into reduced capital costs and lower operating costs of superconducting electrical devices for AC applications.

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.

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.

INTRODUCTION: Physics of Low-dimensional Systems: Nobel Symposium 73

Science.gov (United States)

Lundqvist, Stig

1989-01-01

The physics of low-dimensional systems has developed in a remarkable way over the last decade and has accelerated over the last few years, in particular because of the discovery of the new high temperature superconductors. The new developments started more than fifteen years ago with the discovery of the unexpected quasi-one-dimensional character of the TTF-TCNQ. Since then the field of conducting quasi-one-dimensional organic systems have been rapidly growing. Parallel to the experimental work there has been an important theoretical development of great conceptual importance, such as charge density waves, soliton-like excitations, fractional charges, new symmetry properties etc. A new field of fundamental importance was the discovery of the Quantum Hall Effect in 1980. This field is still expanding with new experimental and theoretical discoveries. In 1986, then, came the totally unexpected discovery of high temperature superconductivity which started an explosive development. The three areas just mentioned formed the main themes of the Symposium. They do not in any way exhaust the progress in low-dimensional physics. We should mention the recent important development with both two-dimensional and one-dimensional and even zero-dimensional structures (quantum dots). The physics of mesoscopic systems is another important area where the low dimensionality is a key feature. Because of the small format of this Symposium we could unfortunately not cover these areas. A Nobel Symposium provides an excellent opportunity to bring together a group of prominent scientists for a stimulating exchange of new ideas and results. The Nobel Symposia are very small meetings by invitation only and the number of key international participants is typically in the range 25-40. These Symposia are arranged through a special Nobel Symposium Committee after proposal from individuals. This Symposium was sponsored by the Nobel Foundation through its Nobel Symposium Fund with grants from The

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.

Progress on a high current density low cost Niobium3Tin conductor scaleable to modern niobium titanium production

Science.gov (United States)

Zeitlin, Bruce A.; Pyon, Taeyoung; Gregory, Eric; Scanlan, R. M.

2002-05-01

A number of configurations of a mono element internal tin conductor (MEIT) were fabricated designed to explore the effect of local ratio, niobium content, and tin content on the overall current density. Critical current densities on four configurations were measured, two to 17T. Current density as a function of filament size was also measured with filaments sizes ranging from 1.8 to 7.1 microns. A Nb60wt%Ta barrier was also explored as a means to reduce the high cost of the Tantalum barrier. The effectiveness of radial copper channels in high Nb conductors is also evaluated. Results are used to suggest designs for more optimized conductors.

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

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....

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.

Organic superconductivity

International Nuclear Information System (INIS)

Jerome, D.

1980-01-01

We present the experimental evidences for the existence of a superconducting state in the Quasi One Dimensional organic conductor (TMTSF) 2 PF 6 . Superconductivity occuring at 1 K under 12 kbar is characterized by a zero resistance diamagnetic state. The anistropy of the upper critical field of this type II superconductor is consistent with the band structure anistropy. We present evidences for the existence of large superconducting precursor effects giving rise to a dominant paraconductive contribution below 40 K. We also discuss the anomalously large pressure dependence of T sb(s), which drops to 0.19 K under 24 kbar in terms of the current theories. (author)

Electronic processes in TTF-derived complexes studied by IR spectroscopy

Science.gov (United States)

Graja, Andrzej

2001-09-01

We focus our attention on the plasma-edge-like dispersion of the reflectance spectra of the selected bis(ethylenodithio)tetrathiafulvalene (BEDT-TTF)-derived organic conductors. The standard procedure to determine the electron transport parameters in low-dimensional organic conductors consists of fitting the appropriate theoretical models with the experimental reflectance data. This procedure provides us with basic information like plasma frequency, the optical effective mass of charge carriers, their number, mean free path and damping constant. Therefore, it is concluded that the spectroscopy is a powerful tool to study the electronic processes in conducting organic solids.

Conductor qualification tests for the 30-MJ Bonneville Power Administration SMES coil

International Nuclear Information System (INIS)

Schermer, R.I.; Boenig, H.J.; Henke, M.; Turner, R.D.; Schramm, R.

1980-01-01

The 30-MJ energy storage coil for the Bonneville Power Administration requires a low-loss, cryostable conductor that is able to carry 4.9 kA in a field of 2.8 T and will maintain its properties over 10 8 partial discharge cycles. The multi-level cable which satisfies these requirements has been extensively tested at various stages in its development and in its final form. Tests have been performed to determine the effect of manufacturing options on ac losses, low temperature electrical resistivity, stability, and fatigue resistance of the insulated conductor. This paper will concentrate on the stability and fatigue tests which have not previously been reported

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...

CT Image Reconstruction in a Low Dimensional Manifold

OpenAIRE

Cong, Wenxiang; Wang, Ge; Yang, Qingsong; Hsieh, Jiang; Li, Jia; Lai, Rongjie

2017-01-01

Regularization methods are commonly used in X-ray CT image reconstruction. Different regularization methods reflect the characterization of different prior knowledge of images. In a recent work, a new regularization method called a low-dimensional manifold model (LDMM) is investigated to characterize the low-dimensional patch manifold structure of natural images, where the manifold dimensionality characterizes structural information of an image. In this paper, we propose a CT image reconstruc...

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

Properties of recent IBAD-MOCVD Coated Conductors relevant to their high field, low temperature magnet use

OpenAIRE

Braccini, V; Xu, A; Jaroszynski, J; Xin, Y; Larbalestier, D C; Chen, Y; Carota, G; Dackow, J; Kesgin, I; Yao, Y; Guevara, A; Shi, T; Selvamanickam, V

2010-01-01

BaZrO3 (BZO) nanorods are now incorporated into production IBAD-MOCVD coated conductors. Here we compare several examples of both BZO-free and BZO-containing coated conductors using critical current (Ic) characterizations at 4.2 K over their full angular range up to fields of 31 T. We find that BZO nanorods do not produce any c-axis distortion of the critical current density Jc(theta) curve at 4.2 K at any field, but also that pinning is nevertheless strongly enhanced compared to the non-BZO ...

Learning Low-Dimensional Metrics

OpenAIRE

Jain, Lalit; Mason, Blake; Nowak, Robert

2017-01-01

This paper investigates the theoretical foundations of metric learning, focused on three key questions that are not fully addressed in prior work: 1) we consider learning general low-dimensional (low-rank) metrics as well as sparse metrics; 2) we develop upper and lower (minimax)bounds on the generalization error; 3) we quantify the sample complexity of metric learning in terms of the dimension of the feature space and the dimension/rank of the underlying metric;4) we also bound the accuracy ...

Calculating transport AC losses in stacks of high temperature superconductor coated conductors with magnetic substrates using FEM

International Nuclear Information System (INIS)

Ainslie, Mark D.; Flack, Tim J.; Campbell, Archie M.

2012-01-01

Properties of stacks of HTS coated conductors with and without a magnetic substrate. Non-magnetic substrate model is consistent with existing methods. Presence of a magnetic substrate increases the total AC loss of the stack. Differences and similarities between certain tapes within stacks are explained. Ferromagnetic loss of substrate negligible in most cases except small currents/fields. In this paper, the authors investigate the electromagnetic properties of stacks of high temperature superconductor (HTS) coated conductors with a particular focus on calculating the total transport AC loss. The cross-section of superconducting cables and coils is often modeled as a two-dimensional stack of coated conductors, and these stacks can be used to estimate the AC loss of a practical device. This paper uses a symmetric two dimensional (2D) finite element model based on the H formulation, and a detailed investigation into the effects of a magnetic substrate on the transport AC loss of a stack is presented. The number of coated conductors in each stack is varied from 1 to 150, and three types of substrate are compared: non-magnetic weakly magnetic and strongly magnetic. The non-magnetic substrate model is comparable with results from existing models for the limiting cases of a single tape (Norris) and an infinite stack (Clem). The presence of a magnetic substrate increases the total AC loss of the stack, due to an increased localized magnetic flux density, and the stronger the magnetic material, the further the flux penetrates into the stack overall. The AC loss is calculated for certain tapes within the stack, and the differences and similarities between the losses throughout the stack are explained using the magnetic flux penetration and current density distributions in those tapes. The ferromagnetic loss of the substrate itself is found to be negligible in most cases, except for small magnitudes of current. Applying these findings to practical applications, where AC

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)

The low-energy limiting behavior of the pseudofermion dynamical theory

International Nuclear Information System (INIS)

Carmelo, J.M.P.; Martelo, L.M.; Penc, K.

2006-01-01

In this paper we show that the general finite-energy spectral-function expressions provided by the pseudofermion dynamical theory for the one-dimensional Hubbard model lead to the expected low-energy Tomonaga-Luttinger liquid correlation function expressions. Moreover, we use the former general expressions to derive correlation-function asymptotic expansions in space and time which go beyond those obtained by conformal-field theory and bosonization: we derive explicit expressions for the pre-factors of all terms of such expansions and find that they have an universal form, as the corresponding critical exponents. Our results refer to all finite values of the on-site repulsion U and to a chain of length L very large and with periodic boundary conditions for the above model, but are of general nature for many integrable interacting models. The studies of this paper clarify the relation of the low-energy Tomonaga-Luttinger liquid behavior to the scattering mechanisms which control the spectral properties at all energy scales and provide a broader understanding of the unusual properties of quasi-one-dimensional nanostructures, organic conductors, and optical lattices of ultracold fermionic atoms. Furthermore, our results reveal the microscopic mechanisms which are behind the similarities and differences of the low-energy and finite-energy spectral properties of the model metallic phase

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 .

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

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.

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

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.

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.

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

Angular dependence of Jc for YBCO coated conductors at low temperature and very high magnetic fields

International Nuclear Information System (INIS)

Xu, A; Jaroszynski, J J; Kametani, F; Chen, Z; Larbalestier, D C; Viouchkov, Y L; Chen, Y; Xie, Y; Selvamanickam, V

2010-01-01

We present very high field angle dependent critical current density (J c ) data for three recently obtained YBa 2 Cu 3 O 7-x (YBCO) coated conductors used in the construction of high field solenoids. We find that strongly correlated pins, such as BaZrO 3 (BZO) nanorods, while yielding strong c-axis peaks at 77 K, produce almost no measurable contribution at 4 K. Raising the field from c (θ) at low fields to a marked cusp-like behavior at high fields. Transmission electron micrographs show that all samples contain a high density of stacking faults which strengthen the plane correlated pinning parallel to the ab planes produced by the intrinsic ab-plane pinning of the Cu-O charge reservoir layers.

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.

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

Three-dimensional vortex pinning by nano-precipitates in a Sm-doped YBa2Cu3O7-x coated conductor

International Nuclear Information System (INIS)

Chen, Z; Feldmann, D M; Song, X; Kim, S I; Gurevich, A; Reeves, J L; Xie, Y Y; Selvamanickam, V; Larbalestier, D C

2007-01-01

We report on the thickness and angular dependence of the critical current density J c (H,θ), the irreversibility field H irr , and the bulk pinning force F p (H) of a metal-organic chemical vapour deposition (MOCVD) grown YBa 2 Cu 3 O 7-x (YBCO) coated conductor, which contains ∼17 vol% of ∼10 nm sized (Y,Sm) 2 O 3 precipitates with an average spacing of ∼10-15 nm. Some surface porosity and amorphous second-phase particles on the scale of ∼0.5-1 μm appear to reduce the current-carrying cross-section, which controls the magnitude of J c but not the vortex pinning. We observed an enhanced H irr ∼9 T at 77 K along the c-axis which, like the shape of J c (H) and F p (H), was independent of thickness as the sample was milled down to ∼0.16 μm. Angular-dependent measurements of J c showed the usual excess vortex pinning along the c-axis and along the ab-plane, but with a background that could only be fitted with an unusually small anisotropy parameter of 3, which, like the high H irr and the thickness-independent shape of F p (H), we ascribe to strong vortex pinning centre interactions. Together, these measurements show very different behaviour from most pulsed-laser-deposited films, which exhibit strong thickness-dependent properties. We ascribe the present different results to the dense array of small, insulating precipitates, which act as strong pinning centres and produce strong three-dimensional (3D) vortex pinning, because their separation of 10-15 nm is always much smaller than the film thickness

In-Plane Angular Effect of Magnetoresistance of Quasi-One-Dimensional Organic Metals, (DMET) 2AuBr 2 and (TMTSF) 2ClO 4

Science.gov (United States)

Yoshino, Harukazu; Saito, Kazuya; Nishikawa, Hiroyuki; Kikuchi, Koichi; Kobayashi, Keiji; Ikemoto, Isao

1997-08-01

Comparative study is presented for the in-plane angular effect of magnetoresistance of quasi-one-dimensional organic conductors, (DMET)2AuBr2 and (TMTSF)2ClO4. The magnetoresistance for the magnetic and electrical fields parallel and perpendicular to the most conducting plane, respectively, was measured at 4.2 K and up to 7.0 T. (DMET)2AuBr2 shows an anomalous hump in the field-orientation dependence of the magnetoresistance for the magnetic field nearly parallel to the most conducting axis and this is very similar to what previously reported for (DMET)2I3. Weak anomaly was detected for the magnetoresistance of (TMTSF)2ClO4 in the Relaxed state, while no anomaly was observed in the SDW phase in the Quenched state. By comparing the numerical angular derivatives of the magnetoresistance, it is shown that the anomaly in the in-plane angular effect continuously develops from zero magnetic field and is closely related to the quasi-one-dimensional Fermi surface. A simple method is proposed to estimate the anisotropy of the transfer integral from the width of the hump anomaly.

Electromagnetic field analyses of two-layer power transmission cables consisting of coated conductors with magnetic and non-magnetic substrates and AC losses in their superconductor layers

International Nuclear Information System (INIS)

Nakahata, Masaaki; Amemiya, Naoyuki

2008-01-01

Two-dimensional electromagnetic field analyses were undertaken using two representative cross sections of two-layer cables consisting of coated conductors with magnetic and non-magnetic substrates. The following two arrangements were used for the coated conductors between the inner and outer layers: (1) tape-on-tape and (2) alternate. The calculated magnetic flux profile around each coated conductor was visualized. In the case of the non-magnetic substrate, the magnetic field to which coated conductors in the outer layer are exposed contains more perpendicular component to the conductor wide face (perpendicular field component) when compared to that in the inner layer. On the other hand, for the tape-on-tape arrangement of coated conductors with a magnetic substrate, the reverse is true. In the case of the alternate arrangement of the coated conductor with a magnetic substrate, the magnetic field to which the coated conductors in the inner and outer layers are exposed experiences a small perpendicular field component. When using a non-magnetic substrate, the AC loss in the superconductor layer of the coated conductors in the two-layer cables is dominated by that in the outer layer, whereas the reverse is true in the case of a magnetic substrate. When comparing the AC losses in superconductor layers of coated conductors with non-magnetic and magnetic substrates in two-layer cables, the latter is larger than the former, but the influence of the magnetism of substrates on AC losses in superconductor layers is not remarkable

Modular assembly of low-dimensional coordination architectures on metal surfaces

International Nuclear Information System (INIS)

Stepanow, Sebastian; Lin, Nian; Barth, Johannes V

2008-01-01

The engineering of highly organized molecular architectures has attracted strong interest because of its potential for novel materials and functional nanoscopic devices. An important factor in the development, integration, and exploitation of such systems is the capability to prepare them on surfaces or in nanostructured environments. Recent advances in supramolecular design on metal substrates provide atomistic insight into the underlying self-assembly processes, mainly by scanning tunneling microscopy observations. This review summarizes progress in noncovalent synthesis strategies under ultra-high vacuum conditions employing metal ions as coordination centers directing the molecular organization. The realized metallosupramolecular compounds and arrays combine the properties of their constituent metal ions and organic ligands, and present several attractive features: their redox, magnetic and spin-state transitions. The presented exemplary molecular level studies elucidate the arrangement of organic adsorbates on metal surfaces, demonstrating the interplay between intermolecular and molecule-substrate interactions that needs to be controlled for the fabrication of low-dimensional structures. The understanding of metallosupramolecular organization and metal-ligand interactions on solid surfaces is important for the control of structure and concomitant function

Preparations and Characterizations of Luminescent Two Dimensional Organic-inorganic Perovskite Semiconductors

Directory of Open Access Journals (Sweden)

Sanjun Zhang

2010-05-01

Full Text Available This article reviews the synthesis, structural and optical characterizations of some novel luminescent two dimensional organic-inorganic perovskite (2DOIP semiconductors. These 2DOIP semiconductors show a self-assembled nano-layered structure, having the electronic structure of multi-quantum wells. 2DOIP thin layers and nanoparticles have been prepared through different methods. The structures of the 2DOIP semiconductors are characterized by atomic force microscopy and X-ray diffraction. The optical properties of theb DOIP semiconductors are characterized from absorption and photoluminescence spectra measured at room and low temperatures. Influences of different components, in particular the organic parts, on the structural and optical properties of the 2DOIP semiconductors are discussed.

Study of the thermo-electronic stability of LTS conductors and contribution to the study of the thermo-electric stability of HTS conductors. Novel techniques to simulate quench precursors in superconducting electro-magnets

International Nuclear Information System (INIS)

Trillaud, F.

2005-09-01

Most of this work deals with the development of new heater technology to simulate quench precursors in super-conducting electro-magnets. The carbon paste point heater and 2 alternative technologies have been used: induction coils and the diode laser. 2 main experimental setups with 2 different heaters have been used to study the stability of Cu/NbTi composite wires. The order of magnitude of the results obtained with the charged point heater and the diode laser is consistent. Our work covered both low critical temperature (LTS) conductors and high critical temperature (HTS) conductors. A large body of data has been gathered on quench energies and normal zone propagation velocities (NZPV). Concerning quench energy: LTS conductors appear largely more sensitive to heat disturbances than HTS conductors. NZPV enables one to define the criteria for which a magnet can be considered as self-protected. It is commonly assumed that, below 1 m/s, active protection is necessary to ensure safe quenches. This is the case for HTS conductors whose NZPV is of the order of a few centimeters per seconds, at most. However, the NZPVs of LTS conductors are above a few meters per seconds. While HTS conductors can suffer from local hot spots which diffuse slowly resulting in damaging overheating, LTS conductors spread the normal zone quickly enough owing to their good thermal conductivity to minimize local overheating. In addition, this gives enough time to dump the energy of the magnet. This work clears a new path to carry out accurate and reproducible experiment on superconductors. It demonstrates the powerfulness of diode laser technology for stability studies. Numerical simulations of the thermal behaviour of a Cu/NbTi multi-filament composite wire have been performed, they are based on a simplified transient liquid helium heat exchange model. This model appears to be not accurate enough to simulate the early time evolution of the voltage between the current sharing temperature and the

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....

Self-field ac losses in biaxially aligned Y endash Ba endash Cu endash O tape conductors

International Nuclear Information System (INIS)

Iijima, Y.; Hosaka, M.; Sadakata, N.; Saitoh, T.; Kohno, O.; Takeda, K.

1997-01-01

Self-field ac losses were measured by the conventional ac four-probe method in biaxially aligned Y endash Ba endash Cu endash O tapes using polycrystalline Hastelloy tapes with textured yttria-stabilized-zirconia buffer layers. The ac losses increased in proportion to the fourth power of transport current in the high J c sample, and agreed well with Norris close-quote equation for thin strip conductors. However, the low J c sample had rather higher losses than Norris close-quote prediction, suggesting excessive magnetic flux penetration caused by percolated current paths. The results confirmed Norris close-quote prediction of the low ac losses for thin strip conductors, and indicated the importance of removing percolated structures of current paths to avoid higher ac losses than the theoretical predictions based on uniform conductors. copyright 1997 American Institute of Physics

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

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

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)....

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)

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.

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.

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

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

Quantum confinement effects in low-dimensional systems

Indian Academy of Sciences (India)

2015-06-03

Jun 3, 2015 ... Quantum confinement effects in low-dimensional systems. Figure 5. (a) Various cuts of the three-dimensional data showing energy vs. momen- tum dispersion relations for Ag film of 17 ML thickness on Ge(111). (b) Photo- emission intensity maps along ¯M– ¯ – ¯K direction. (c) Substrate bands replotted ...

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.

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)

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.

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

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.

Simulation of propagation along an isolated skeletal muscle fiber in an isotropic volume conductor

DEFF Research Database (Denmark)

Henneberg, Kaj-åge; F.A., Roberge

1997-01-01

This paper describes a model of the frog skeletal muscle fiber that includes the effects of the transverse tubular system (T system) on propagation. Uniform propagation on an isolated fiber suspended in Ringer's solution or in air is simulated by placing the cylindrical fiber model in a concentric...... three-dimensional isotropic volume conductor. The current through the T system outlets at the sarcolemmal surface is comparable in magnitude to the sarcolemmal current density, but is of opposite polarity. When it is added to the sarcolemmal current, the resulting triphasic waveform has a 100% increase...... of the extracellular potential. Compared to an isolated fiber in a large volume of Ringer's solution, uniform propagation within a 2-mu m-thick volume conductor annulus is slowed down from 1.92 to 0.72 m/s, and the extracellular potential is increased from 1 to 108 mV peak to peak, in agreement with published...

Three-dimensional rail-current distribution near the armature of simple, square-bore, two-rail railguns

International Nuclear Information System (INIS)

Beno, J.H.

1991-01-01

In this paper vector potential is solved as a three dimensional, boundary value problem for a conductor geometry consisting of square-bore railgun rails and a stationary armature. Conductors are infinitely conducting and perfect contact is assumed between rails and the armature. From the vector potential solution, surface current distribution is inferred

Low-Dimensional Nanomaterials as Active Layer Components in Thin-Film Photovoltaics

Science.gov (United States)

Shastry, Tejas Attreya

to result in record breaking performance in a carbon nanotube solar cell, and subsequent chapters study the mechanisms behind charge transfer in the polychiral carbon nanotube / fullerene solar cell. Further processing advances, chiral distribution tailoring, and solvent additives are shown to enable more uniform and larger area carbon nanotube solar cells while maintaining record-breaking performance. In order to increase overall photovoltaic performance of a carbon nanotube active layer solar cell, this dissertation also demonstrates a ternary polymer-carbon nanotube-small molecule photovoltaic with high efficiency and stability enabled by the nanomaterial. Finally, the use of the two-dimensional metal dichalcogenide molybdenum disulfide as a photovoltaic material is explored in an ultrathin solar cell with higher efficiency per thickness than leading organic and inorganic thin-film photovoltaics. Overall, this work demonstrates breakthroughs in utilizing low-dimensional nanomaterials as active layer components in photovoltaics and will inform ongoing research in making ultrathin, stable, efficient solar cells.

High-response hybrid quantum dots- 2D conductor phototransistors: recent progress and perspectives

Science.gov (United States)

Sablon, Kimberly A.; Sergeev, Andrei; Najmaei, Sina; Dubey, Madan

2017-03-01

Having been inspired by the tremendous progress in material nanoscience and device nanoengineering, hybrid phototransistors combine solution processed colloidal semiconductor quantum dots (QDs) with graphene or two-dimensional (2D) semiconductor materials. Novel detectors demonstrate ultrahigh photoconductive gain, high and selective photoresponse, low noise, and very high responsivity in visible- and near-infrared ranges. The outstanding performance of phototransistors is primarily due to the strong, selective, and size tunable absorption of QDs and fast charge transfer in 2D high mobility conductors. However, the relatively small mobility of QD nanomaterials was a technological barrier, which limited the operating rate of devices. Very recent innovations in detector design and significant progress in QD ligand engineering provide effective tools for further qualitative improvements. This article reviews the recent progress in material science, nanophysics, and device engineering related to hybrid phototransistors. Detectors based on various QD nanomaterials and several 2D conductors are compared, and advantages and disadvantages of various nanomaterials for applications in hybrid phototransistors are identified. We also benchmark the experimental characteristics with model results that establish interrelations and tradeoffs between detector characteristics, such as responsivity, dark and noise currents, the photocarrier lifetime, response, and noise bandwidths. We have shown that the most recent phototransistors demonstrate performance limited by the fundamental generation recombination noise in high gain devices. Interrelation between the dynamic range of the detector and the detector sensitivity is discussed. The review is concluded with a brief discussion of the remaining challenges and possible significant improvements in the performance of hybrid phototransistors.

High-response hybrid quantum dots- 2D conductor phototransistors: recent progress and perspectives

Directory of Open Access Journals (Sweden)

Sablon Kimberly A.

2017-03-01

Full Text Available Having been inspired by the tremendous progress in material nanoscience and device nanoengineering, hybrid phototransistors combine solution processed colloidal semiconductor quantum dots (QDs with graphene or two-dimensional (2D semiconductor materials. Novel detectors demonstrate ultrahigh photoconductive gain, high and selective photoresponse, low noise, and very high responsivity in visible- and near-infrared ranges. The outstanding performance of phototransistors is primarily due to the strong, selective, and size tunable absorption of QDs and fast charge transfer in 2D high mobility conductors. However, the relatively small mobility of QD nanomaterials was a technological barrier, which limited the operating rate of devices. Very recent innovations in detector design and significant progress in QD ligand engineering provide effective tools for further qualitative improvements. This article reviews the recent progress in material science, nanophysics, and device engineering related to hybrid phototransistors. Detectors based on various QD nanomaterials and several 2D conductors are compared, and advantages and disadvantages of various nanomaterials for applications in hybrid phototransistors are identified. We also benchmark the experimental characteristics with model results that establish interrelations and tradeoffs between detector characteristics, such as responsivity, dark and noise currents, the photocarrier lifetime, response, and noise bandwidths. We have shown that the most recent phototransistors demonstrate performance limited by the fundamental generation recombination noise in high gain devices. Interrelation between the dynamic range of the detector and the detector sensitivity is discussed. The review is concluded with a brief discussion of the remaining challenges and possible significant improvements in the performance of hybrid phototransistors.

Quantum Phenomena in Low-Dimensional Systems

OpenAIRE

Geller, Michael R.

2001-01-01

A brief summary of the physics of low-dimensional quantum systems is given. The material should be accessible to advanced physics undergraduate students. References to recent review articles and books are provided when possible.

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.

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.

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

Magnet design with 100-kA HTS STARS conductors for the helical fusion reactor

Science.gov (United States)

Yanagi, N.; Terazaki, Y.; Ito, S.; Tamura, H.; Hamaguchi, S.; Mito, T.; Hashizume, H.; Sagara, A.

2016-12-01

The high-temperature superconducting (HTS) option is employed for the conceptual design of the LHD-type helical fusion reactor FFHR-d1. The 100-kA-class STARS (Stacked Tapes Assembled in Rigid Structure) conductor is used for the magnet system including the continuously wound helical coils. Protection of the magnet system in case of a quench is a crucial issue and the hot-spot temperature during an emergency discharge is estimated based on the zero-dimensional and one-dimensional analyses. The number of division of the coil winding package is examined to limit the voltage generation. For cooling the HTS magnet, helium gas flow is considered and its feasibility is examined by simple analysis as a first step.

Controlling the mode of operation of organic transistors through side-chain engineering

KAUST Repository

Giovannitti, Alexander

2016-10-11

Electrolyte-gated organic transistors offer low bias operation facilitated by direct contact of the transistor channel with an electrolyte. Their operation mode is generally defined by the dimensionality of charge transport, where a field-effect transistor allows for electrostatic charge accumulation at the electrolyte/semiconductor interface, whereas an organic electrochemical transistor (OECT) facilitates penetration of ions into the bulk of the channel, considered a slow process, leading to volumetric doping and electronic transport. Conducting polymer OECTs allow for fast switching and high currents through incorporation of excess, hygroscopic ionic phases, but operate in depletion mode. Here, we show that the use of glycolated side chains on a thiophene backbone can result in accumulation mode OECTs with high currents, transconductance, and sharp subthreshold switching, while maintaining fast switching speeds. Compared with alkylated analogs of the same backbone, the triethylene glycol side chains shift the mode of operation of aqueous electrolyte-gated transistors from interfacial to bulk doping/transport and show complete and reversible electrochromism and high volumetric capacitance at low operating biases. We propose that the glycol side chains facilitate hydration and ion penetration, without compromising electronic mobility, and suggest that this synthetic approach can be used to guide the design of organic mixed conductors.

Controlling the mode of operation of organic transistors through side-chain engineering

Science.gov (United States)

Giovannitti, Alexander; Sbircea, Dan-Tiberiu; Inal, Sahika; Nielsen, Christian B.; Bandiello, Enrico; Hanifi, David A.; Sessolo, Michele; Malliaras, George G.; McCulloch, Iain; Rivnay, Jonathan

2016-01-01

Electrolyte-gated organic transistors offer low bias operation facilitated by direct contact of the transistor channel with an electrolyte. Their operation mode is generally defined by the dimensionality of charge transport, where a field-effect transistor allows for electrostatic charge accumulation at the electrolyte/semiconductor interface, whereas an organic electrochemical transistor (OECT) facilitates penetration of ions into the bulk of the channel, considered a slow process, leading to volumetric doping and electronic transport. Conducting polymer OECTs allow for fast switching and high currents through incorporation of excess, hygroscopic ionic phases, but operate in depletion mode. Here, we show that the use of glycolated side chains on a thiophene backbone can result in accumulation mode OECTs with high currents, transconductance, and sharp subthreshold switching, while maintaining fast switching speeds. Compared with alkylated analogs of the same backbone, the triethylene glycol side chains shift the mode of operation of aqueous electrolyte-gated transistors from interfacial to bulk doping/transport and show complete and reversible electrochromism and high volumetric capacitance at low operating biases. We propose that the glycol side chains facilitate hydration and ion penetration, without compromising electronic mobility, and suggest that this synthetic approach can be used to guide the design of organic mixed conductors. PMID:27790983

Asymmetrically doped one-dimensional trans-polymers

International Nuclear Information System (INIS)

Caldas, Heron

2009-01-01

More than 30 years ago [H. Shirakawa, E.J. Louis, A.G. MacDiarmid, C.K. Chiang, A.J. Heeger, J. Chem. Soc. Chem. Comm. 578 (1977); S. Etemad, A.J. Heeger, Ann. Rev. Phys. Chem. 33 (1982) 443] it was discovered that doped trans-polyacetylene (CH) x , a one-dimensional (1D) conjugated polymer, exhibits electrical conductivity. In this work we show that an asymmetrically doped 1D trans-polymer has non-conventional properties, as compared to symmetrically doped systems. Depending on the level of asymmetry between the chemical potentials of the two involved fermionic species, the polymer can be in a partially or fully spin polarized state. Some possible experimental consequences of doped 1D trans-polymers used as 1D organic polarized conductors are discussed.

Gain enhancement of low profile on-chip dipole antenna via Artificial Magnetic Conductor at 94 GHz

KAUST Repository

Nafe, Mahmoud

2015-04-13

The bottleneck for realizing high efficiency System-on-Chip is integrating the antenna on the lossy silicon substrate. To shield the antenna from the silicon, a ground plane can be used. However, the ultra-thin oxide does not provide enough separation between the antenna and the ground plane. In this work, we demonstrate one of the highest reported gains to date for low profile 94 GHz on-chip dipole antenna while the ground plane is in the lowest metal in the oxide (M1). This is achieved by optimizing an Artificial Magnetic Conductor (AMC) structure midway the antenna and M1. The dipole antenna without the AMC has a gain of − 11 dBi while with the AMC structure a gain of + 4.8 dBi and hence achieving a gain enhancement of + 15.8 dB.

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.

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.

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

Future device applications of low-dimensional carbon superlattice structures

Science.gov (United States)

Bhattacharyya, Somnath

2005-03-01

We observe superior transport properties in low-dimensional amorphous carbon (a-C) and superlattice structures fabricated by a number of different techniques. Low temperature conductivity of these materials is explained using argument based on the crossover of dimensionality of weak localization and electron-electron interactions along with a change of sign of the magneto-resistance. These trends are significantly different from many other well characterized ordered or oriented carbon structures, and, show direct evidence of high correlation length, mobility and an effect of the dimensionality in low-dimensional a-C films. We show routes to prepare bespoke features by tuning the phase relaxation time in order to make high-speed devices over large areas. The artificially grown multi-layer superlattice structures of diamond-like amorphous carbon films show high-frequency resonance and quantum conductance suggesting sufficiently high values of phase coherence length in the present disordered a-C system that could lead to fast switching multi-valued logic.

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.

EU ITER TF coil: Dimensional metrology, a key player in the Double Pancake integration

International Nuclear Information System (INIS)

Poncet, L.; Bellesia, B.; Oliva, A. Bonito; Boter Rebollo, E.; Cornelis, M.; Cornella Medrano, J.; Harrison, R.; Bue, A. Lo; Moreno, A.; Foussat, A.; Felipe, A.; Echeandia, A.; Barutti, A.; Caserza, B.; Barbero, P.; Stenca, S.; Da Re, A.; Silva Ribeiro, J.; Brocot, C.; Benaoun, S.

2015-01-01

Highlights: • Development and qualification of a dimensional metrology procedure on wound superconductor trajectory based on Laser scanning system. • Dimensional control of the conductor centreline during winding, before and after heat treatment. • Radial Plate groove centreline length controlled using Laser Trackers. • Full scale wound Double Pancake prototype transferred inside Radial Plate prototype without any issues. - Abstract: The ITER Toroidal Field (TF) magnet system consists of 18 “D” shaped coils. Fusion for Energy (F4E), the European Domestic Agency for ITER, is responsible for the supply of 10 out the 19 TF coils (18 installed plus one spare coil). Each TF coil, about 300 t in weight, is made of a stainless steel case containing a Winding Pack (WP). The European manufacturing of the Radial Plates (RPs) and WPs has been awarded to two different industrial partners, whose activities are strongly linked with each other. In order to manufacture a Double Pancake (DP), first, the conductor has to be bent onto a D-shaped double spiral trajectory, then heat treated and inserted in the grooves of the RP. This represents the most challenging manufacturing step: in order to fit inside the groove, the double spiral trajectory of the conductor must match almost perfectly the trajectory of the groove, over a length above 700 m. In order to achieve this, the conductor trajectory length must be controlled with an accuracy of 1 mm over a length of 350 m while the radial plate groove has to be machined with tolerances of ±0.2 mm over dimensions of more than 10 m. In order to succeed, it has been essential to develop a metrology process capable to control with high accuracy both the DP conductor and the RP groove trajectories. This paper reports on the work carried out on the development and qualification of the dimensional metrology to monitor the manufacturing of the conductor. Reference is made to the final dimensional check of the RP focusing on the

Characterization of long-length, MOCVD-derived REBCO coated conductors.

Energy Technology Data Exchange (ETDEWEB)

Miller, D. J.; Maroni, V. A.; Hiller, J. M.; Koritala, R. E.; Chen, Y.; Reeves Black, J. L.; Selvamanickam, V.; SuperPower, Inc.; Development Dimensions International, Inc.

2009-06-01

A leading approach to the fabrication of long-length, high-performance REBa{sub 2}Cu{sub 3}O{sub 7} (REBCO) coated conductor is by metal-organic chemical vapor deposition (MOCVD) of REBCO on buffered templates. Templates are produced by ion beam assisted deposition of textured MgO onto polished metal substrates. The overall performance of MOCVD coated conductors achieved to date is impressive, but further improvement is desired. We have used a coordinated set of characterization techniques to identify the underlying causes for critical current (Ic) performance variations in long-length MOCVD conductors. Using electron microscopy and Raman spectroscopy, we studied tape specimens from specially designed experiments performed in SuperPower's MOCVD manufacturing equipment with its six-track ldquohelixrdquo tape path. We find that in multi-pass depositions used to produce thicker REBCO films, the REBCO phase uniformity and texture quality in the first pass play key roles in pass-to-pass microstructure evolution, with nucleation of second phase particles in the first layer promoting misoriented grains that propagate through subsequent layers. These misoriented grains, many growing in close proximity with second phase particles, present current-blocking obstacles that limit Ic performance. Our results show that achieving more uniform deposition in the very first deposited layer plays a critical role that in turn leads to reduced misoriented grain content and REBCO lattice disorder in the second and subsequent layers of the REBCO film.

Three-dimensional Organotypic Cultures of Vestibular and Auditory Sensory Organs.

Science.gov (United States)

Gnedeva, Ksenia; Hudspeth, A J; Segil, Neil

2018-06-01

The sensory organs of the inner ear are challenging to study in mammals due to their inaccessibility to experimental manipulation and optical observation. Moreover, although existing culture techniques allow biochemical perturbations, these methods do not provide a means to study the effects of mechanical force and tissue stiffness during development of the inner ear sensory organs. Here we describe a method for three-dimensional organotypic culture of the intact murine utricle and cochlea that overcomes these limitations. The technique for adjustment of a three-dimensional matrix stiffness described here permits manipulation of the elastic force opposing tissue growth. This method can therefore be used to study the role of mechanical forces during inner ear development. Additionally, the cultures permit virus-mediated gene delivery, which can be used for gain- and loss-of-function experiments. This culture method preserves innate hair cells and supporting cells and serves as a potentially superior alternative to the traditional two-dimensional culture of vestibular and auditory sensory organs.

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.

Manufacture of mineral-insulated conductor for ITER prototype ELM and VS coil

International Nuclear Information System (INIS)

Long, Feng; Wu, Yu; Jin, Huan; Yu, Min; Han, Qiyang; Ling, Feng; Kalish, Michael

2015-01-01

Highlights: • Compaction method is successfully developed for MIC manufacture. • Manufactured MICs show well controlled outer diameter and good electrical properties. • Insulation resistance of all the MICs is higher than 100 GΩ@DC 2500 V. - Abstract: An ITER Organization (IO) Task Agreement (TA) “Final Design and Prototyping of the ITER In-Vessel Coils (IVC) and Feeders” is almost finished by Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). ITER IVCs consist of edge-localized mode (ELM) and vertical stabilization (VS) coils. One prototype Mid-ELM coil complete with 19 brackets brazed with the conductors and one prototype 120° section of upper VS coil with structural components brazed to the conductors have been fabricated. Compaction method is developed successfully for the mineral-insulated conductor (MIC) manufacture. Approximate 110 m Inconel 625 jacket MICs for Mid-ELM prototype coil and 80 m stainless steel 316L jacket MICs for VS prototype coil were manufactured. Most of the copper tubes used for the MICs fabrication failed the ultrasonic testing (UT), but the jacket tubes have good passing rate. Manufacture processes and inspection for the MICs are presented in this paper

Manufacture of mineral-insulated conductor for ITER prototype ELM and VS coil

Energy Technology Data Exchange (ETDEWEB)

Long, Feng, E-mail: longf@ipp.ac.cn [Institute of Plasma Physics of Chinese Academy of Sciences, Hefei 230031 (China); Wu, Yu; Jin, Huan; Yu, Min; Han, Qiyang; Ling, Feng [Institute of Plasma Physics of Chinese Academy of Sciences, Hefei 230031 (China); Kalish, Michael [Princeton Plasma Physics Laboratory, PO Box 451, Princeton, NJ 08543 (United States)

2015-06-15

Highlights: • Compaction method is successfully developed for MIC manufacture. • Manufactured MICs show well controlled outer diameter and good electrical properties. • Insulation resistance of all the MICs is higher than 100 GΩ@DC 2500 V. - Abstract: An ITER Organization (IO) Task Agreement (TA) “Final Design and Prototyping of the ITER In-Vessel Coils (IVC) and Feeders” is almost finished by Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). ITER IVCs consist of edge-localized mode (ELM) and vertical stabilization (VS) coils. One prototype Mid-ELM coil complete with 19 brackets brazed with the conductors and one prototype 120° section of upper VS coil with structural components brazed to the conductors have been fabricated. Compaction method is developed successfully for the mineral-insulated conductor (MIC) manufacture. Approximate 110 m Inconel 625 jacket MICs for Mid-ELM prototype coil and 80 m stainless steel 316L jacket MICs for VS prototype coil were manufactured. Most of the copper tubes used for the MICs fabrication failed the ultrasonic testing (UT), but the jacket tubes have good passing rate. Manufacture processes and inspection for the MICs are presented in this paper.

Dielectric spectroscopy studies of low-disorder and low-dimensional materials

OpenAIRE

Tripathi, Pragya

2016-01-01

In this thesis we employ dielectric spectroscopy (in different implementations) to study the dielectric properties of different materials ranging from completely disordered supercooled liquids to low-disorder solids with only ratcheting reorientational motions, to low-dimensional systems such as thin films or needle-like crystals. The probed material properties include the electrical conductivity, the space-charge processes due to sample heterogeneities, molecular dynamics, hydrogen-bond dyna...

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.

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)

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

Phase Evolution of YBa2Cu3O7-x films by all-chemical solution deposition route for coated conductors

DEFF Research Database (Denmark)

Yue, Zhao; Tang, Xiao; Wu, Wei

2014-01-01

In order to understand the all-chemical-solution-deposition (CSD) processes for manufacturing coated conductors, we investigated the phase evolution of YBa2Cu3O7 (YBCO) films deposited by a low-fluorine metal-organic solution deposition (LF-MOD) method on CSD derived Ce0.9La0.1O2/Gd2Zr2O7/Ni......W. It is shown that the phase transition from the pyrolyzed film to fully converted YBCO film in the LF-MOD process is similar to that in typical trifluoroacetates-metal organic deposition (TFA-MOD) processes even though the amount of TFA in the solution is reduced by almost one half compared with typical TFA...

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.

Study of structure of HTS coated conductor with ferromagnetic substrate having low AC transport current loss using FEM

International Nuclear Information System (INIS)

Miyagi, D.; Amadutsumi, Y.; Takahashi, N.; Tsukamoto, O.

2007-01-01

AC transport current losses of coated conductors with ferromagnetic substrates are higher than the loss calculated by the Norris equation. In order to reduce the AC transport current loss we propose in this paper a structure of the coated conductor that has wider substrate than the SC (Superconducting) layer. The current distribution and AC loss of the proposed model are analyzed by means of FEM. The AC transport current loss is reduced due to the change of current density distribution near the edge of SC layer, consequent to the high value of magnetic permeability of the ferromagnetic substrate, that is wider than the SC layer

Two-Dimensional Perovskite Activation with an Organic Luminophore.

Science.gov (United States)

Jemli, Khaoula; Audebert, Pierre; Galmiche, Laurent; Trippé-Allard, Gaelle; Garrot, Damien; Lauret, Jean-Sébastien; Deleporte, Emmanuelle

2015-10-07

A great advantage of the hybrid organic-inorganic perovskites is the chemical flexibility and the possibility of a molecular engineering of each part of the material (the inorganic part and the organic part respectively) in order to improve or add some functionalities. An adequately chosen organic luminophore has been introduced inside a lead bromide type organic-inorganic perovskite, while respecting the two-dimensional perovskite structure. A substantial increase of the brilliance of the perovskite is obtained. This activation of the perovskite luminescence by the adequate engineering of the organic part is an original approach, and is particularly interesting in the framework of the light-emitting devices such as organic light-emitting diodes (OLEDs) or lasers.

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.

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

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 ...

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

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

Properties of recent IBAD-MOCVD coated conductors relevant to their high field, low temperature magnet use

International Nuclear Information System (INIS)

Braccini, V; Xu, A; Jaroszynski, J; Xin, Y; Larbalestier, D C; Chen, Y; Carota, G; Dackow, J; Kesgin, I; Yao, Y; Guevara, A; Shi, T; Selvamanickam, V

2011-01-01

BaZrO 3 (BZO) nanorods are now incorporated into production IBAD-MOCVD coated conductors. Here we compare several examples of both BZO-free and BZO-containing coated conductors using critical current (I c ) characterizations at 4.2 K over their full angular range up to fields of 31 T. We find that BZO nanorods do not produce any c-axis distortion of the critical current density J c (θ) curve at 4.2 K at any field, but also that pinning is nevertheless strongly enhanced compared to the non-BZO conductors. We also find that the tendency of the ab-plane J c (θ) peak to become cusp-like is moderated by BZO and we define a new figure of merit that may be helpful for magnet design-the OADI (off-axis double I c ), which clearly shows that BZO broadens the ab-plane peak and thus raises J c 5 0 -30 0 away from the tape plane, where the most critical approach to I c occurs in many coil designs. We describe some experimental procedures that may make critical current I c tests of these very high current tapes more tractable at 4.2 K, where I c exceeds 1000 A even for 4 mm wide tape with only 1 μm thickness of superconductor. A positive conclusion is that BZO is very beneficial for the J c characteristics at 4.2 K, just as it is at higher temperatures, where the correlated c-axis pinning effects of the nanorods are much more obvious.

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

One-dimensional low spatial frequency LIPSS with rotating orientation on fused silica

Energy Technology Data Exchange (ETDEWEB)

Schwarz, Simon, E-mail: simon.schwarz@h-ab.de; Rung, Stefan; Hellmann, Ralf

2017-07-31

Highlights: • Generation of one-dimensional low spatial frequency LIPSS on transparent material. • Varying the angle of incidence results in a rotation of the one-dimensional LSFL. • Rotation angle of LSFL decreases with increasing the applied fluence. • Orientation of the LSFL is mirror-inverted when reversing the scanning direction. - Abstract: We report on the generation of one-dimensional low spatial frequency LIPSS on transparent material. The influence of the applied laser fluence and angle of incidence on the periodicity, orientation and quality of the one-dimensional low spatial frequency LIPSS is investigated, facilitating the generation of highly uniform LIPSS alongside a line. Most strikingly, however, we observe a previously unreported effect of a pronounced rotation of the one-dimensional low spatial frequency LIPSS for varying angle of incidence upon inclined laser irradiation.

Disorder and conductivity of organic metal

International Nuclear Information System (INIS)

Bouffard, Serge

1982-02-01

At high temperature, quasi-one-dimensional organic conductors are metallic; at low temperature, the electron gas instabilities drive either a metal to insulator transition or a metal to superconductor transition. Precursors of these 3-D ordering could be appear at higher temperature. A study of the effects of irradiation induced defects on a few organic complexes has shown that defects are produced by radiolitic process. Their concentration can be easily deduced from resistivity measurement at room temperature. In the metallic state, the defects act as strong potentials which break the conducting chains and force the electron to jump to the neighbourg stack. The defects produce a mixing between longitudinal and transverse conductivities. While, it is the 3-D effect of the defects which pins the charge density waves and thus the 3-D ordering can not be acheived: the metal to insulator transition is destroyed, the metallic state is stabilized. In the same time, the fluctuative conductivity is suppress. The superconducting regime has been found to be extremely sensitive to irradiation induced defects. Thus we can demonstrate that the 1-D superconducting fluctuations contribute to the conductivity and that the transition temperature is correlated to the 3-D superconducting fluctuations. [fr

Large superconducting conductors and joints for fusion magnets: From conceptual design to test at full size scale

International Nuclear Information System (INIS)

Ciazynski, D.; Duchateau, J.L.; Decool, P.; Libeyre, P.; Turck, B.

2001-01-01

A new kind of superconducting conductor, using the so-called cable-in-conduit concept, is emerging mainly involving fusion activity. It is to be noted that at present time no large Nb 3 Sn magnet in the world is operating using this concept. The difficulty of this technology which has now been studied for 20 years, is that it has to integrate major progresses in multiple interconnected new fields such as: large number (1000) of superconducting strands, high current conductors (50 kA), forced flow cryogenics, Nb 3 Sn technology, low loss conductors in pulsed operation, high current connections, high voltage insulation (10 kV), economical and industrial feasibility. CEA was very involved during these last 10 years in this development which took place in the frame of the NET and ITER technological programs. One major milestone was reached in 1998-1999 with the successful tests by our Association of three full size conductor and connection samples in the Sultan facility (Villigen, Switzerland). (author)

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.

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

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

Inelastic light scattering by low-lying excitations of electrons in low-dimensional semiconductors

Energy Technology Data Exchange (ETDEWEB)

Pellegrini, V. [NEST CNR-INFM and Scuola Normale Superiore, Pisa (Italy); Pinczuk, A. [Department of Physics, Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States); Bell Laboratories, Lucent Technologies, Murray Hill, New Jersey (United States)

2006-11-15

The low-dimensional electron systems that reside in artificial semiconductor heterostructures of great perfection are a contemporary materials base for explorations of collective phenomena. Studies of low-lying elementary excitations by inelastic light scattering offer insights on properties such energetics, interactions and spin magnetization. We review here recent light scattering results obtained from two-dimensional (2D) quantum fluids in semiconductor heterostructures under extreme conditions of low temperature and large magnetic field, where the quantum Hall phases are archetypes of novel behaviors. We also consider recent light scattering experiments that have probed the excitation spectra of few-electron states in semiconductor quantum dots. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

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.

Fabrication, Characterization, Properties, and Applications of Low-Dimensional BiFeO3 Nanostructures

Directory of Open Access Journals (Sweden)

Heng Wu

2014-01-01

Full Text Available Low-dimensional BiFeO3 nanostructures (e.g., nanocrystals, nanowires, nanotubes, and nanoislands have received considerable attention due to their novel size-dependent properties and outstanding multiferroic properties at room temperature. In recent years, much progress has been made both in fabrications and (microstructural, electrical, and magnetic in characterizations of BiFeO3 low-dimensional nanostructures. An overview of the state of art in BiFeO3 low-dimensional nanostructures is presented. First, we review the fabrications of high-quality BiFeO3 low-dimensional nanostructures via a variety of techniques, and then the structural characterizations and physical properties of the BiFeO3 low-dimensional nanostructures are summarized. Their potential applications in the next-generation magnetoelectric random access memories and photovoltaic devices are also discussed. Finally, we conclude this review by providing our perspectives to the future researches of BiFeO3 low-dimensional nanostructures and some key problems are also outlined.

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...

From Two- to Three-Dimensional Structures of a Supertetrahedral Boran Using Density Functional Calculations.

Science.gov (United States)

Getmanskii, Iliya V; Minyaev, Ruslan M; Steglenko, Dmitrii V; Koval, Vitaliy V; Zaitsev, Stanislav A; Minkin, Vladimir I

2017-08-14

With help of the DFT calculations and imposing of periodic boundary conditions the geometrical and electronic structures were investigated of two- and three-dimensional boron systems designed on the basis of graphane and diamond lattices in which carbons were replaced with boron tetrahedrons. The consequent studies of two- and three-layer systems resulted in the construction of a three-dimensional supertetrahedral borane crystal structure. The two-dimensional supertetrahedral borane structures with less than seven layers are dynamically unstable. At the same time the three-dimensional superborane systems were found to be dynamically stable. Lack of the forbidden electronic zone for the studied boron systems testifies that these structures can behave as good conductors. The low density of the supertetrahedral borane crystal structures (0.9 g cm -3 ) is close to that of water, which offers the perspective for their application as aerospace and cosmic materials. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

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.

Low-dimensional chaos in a hydrodynamic system

International Nuclear Information System (INIS)

Brandstater, A.; Swift, J.; Swinney, H.L.; Wolf, A.; Farmer, J.D.; Jen, E.; Crutchfield, J.P.

1983-01-01

Evidence is presented for low-dimensional strange attractors in Couette-Taylor flow data. Computations of the largest Lyapunov exponent and metric entropy show that the system displays sensitive dependence on initial conditions. Although the phase space is very high dimensional, analysis of experimental data shows that motion is restricted to an attractor of dimension less than 5 for Reynolds numbers up to 30% above the onset of chaos. The Lyapunov exponent, entropy, and dimension all generally increase with Reynolds number

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

One-dimensional organic lead halide perovskites with efficient bluish white-light emission

Science.gov (United States)

Yuan, Zhao; Zhou, Chenkun; Tian, Yu; Shu, Yu; Messier, Joshua; Wang, Jamie C.; van de Burgt, Lambertus J.; Kountouriotis, Konstantinos; Xin, Yan; Holt, Ethan; Schanze, Kirk; Clark, Ronald; Siegrist, Theo; Ma, Biwu

2017-01-01

Organic-inorganic hybrid metal halide perovskites, an emerging class of solution processable photoactive materials, welcome a new member with a one-dimensional structure. Herein we report the synthesis, crystal structure and photophysical properties of one-dimensional organic lead bromide perovskites, C4N2H14PbBr4, in which the edge sharing octahedral lead bromide chains [PbBr4 2-]∞ are surrounded by the organic cations C4N2H14 2+ to form the bulk assembly of core-shell quantum wires. This unique one-dimensional structure enables strong quantum confinement with the formation of self-trapped excited states that give efficient bluish white-light emissions with photoluminescence quantum efficiencies of approximately 20% for the bulk single crystals and 12% for the microscale crystals. This work verifies once again that one-dimensional systems are favourable for exciton self-trapping to produce highly efficient below-gap broadband luminescence, and opens up a new route towards superior light emitters based on bulk quantum materials.

Low-dimensional chaotic attractors in drift wave turbulence

International Nuclear Information System (INIS)

Persson, M.; Nordman, H.

1991-01-01

Simulation results of toroidal η i -mode turbulence are analyzed using mathematical tools of nonlinear dynamics. Low-dimensional chaotic attractors are found in the strongly nonlinear regime while in the weakly interacting regime the dynamics is high dimensional. In both regimes, the solutions are found to display sensitive dependence on initial conditions, characterized by a positive largest Liapunov exponent. (au)

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

Final Technical Report, Grant DE-FG02-91ER45443: Heavy fermions and other highly correlated electron systems

International Nuclear Information System (INIS)

Schlottmann, P.

1998-01-01

Properties of highly correlated electrons, such as heavy fermion compounds, metal-insulator transitions, one-dimensional conductors and systems of restricted dimensionality are studied theoretically. The main focus is on Kondo insulators and impurity bands due to Kondo holes, the low-temperature magnetoresistivity of heavy fermion alloys, the n-channel Kondo problem, mesoscopic systems and one-dimensional conductors

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.

A High-gain and Low-scattering Waveguide Slot Antenna of Artificial Magnetic Conductor Octagonal Ring Arrangement

Directory of Open Access Journals (Sweden)

X. Liu

2016-04-01

Full Text Available A novel design of high-gain and low-scattering waveguide slot antenna is proposed in this paper. Firstly the scattering pattern of artificial magnetic conductor (AMC composite surface is estimated by array factor analysis method. The comparison between octagonal ring arrangement and chessboard arrangement proves that the former arrangement has the characteristic of diffuseness-like and expands the bandwidth of radar cross section (RCS reduction. Secondly, the metal surface of waveguide slot antenna (WSA is replaced by the octagonal ring arrangement composite surface (ORACS. The gain is improved because of spurious radiation units which are around the slot. At the same time using the phase cancellation principle, a backscatter null achieves RCS reduction in the vertical direction. Experimental results show that the novel antenna after loading with the ORACS, the gain is improved by 5dB; the bandwidth of RCS reduction (reduction greater than 10dB is 5.24-5.92 GHz.

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.

Development of a 20kA current feedthrough using YBCO bulk conductors

International Nuclear Information System (INIS)

Maehata, Keisuke; Ishibashi, Kenji; Shintomi, Takakazu; Iwamoto, Akifumi; Maekawa, Ryuji; Mito, Toshiyuki

2004-01-01

In the phase II experiment of the Large Helical Device (LHD) of the National Institute for Fusion Science (NIFS), it is planned to operate the helical coils at 1.8 K by employing pressurized superfluid cooling to raise the magnetic field to 4 T with 17.3 kA. It is important to develop a 20kA-class current feedthrough into the 1.8 K region, but it must have a high current capacity and low heat leakage in the maximum magnetic leakage field of 1 T. Rectangle-shaped YBCO bulk conductors measuring 20 mm wide, 140 mm long and 10 mm thick were manufactured from square-pillar-shaped YBCO bulk materials for a 20 kA current. To check the quality of the bulk conductors, internal defects or cracks were detected by carrying out a precise survey of trapped magnetic flux. An assembled 20 kA current feedthrough was mounted in the λ-plate of a pressurized superfluid cooling cryostat. Experiments of current feeding into the 1.8 K region were carried out by operating the 20 kA current feedthrough. In the experiments, the transport current was kept at 20 kA for longer than 1,200 s. During the 20 kA operation, the current transport section of the YBCO bulk conductors remained in the superconducting state and the voltage drop between the YBCO bulk conductors and the copper electrode was observed to be constant. A contact resistance and the Joule heat generation in the joint region between the YBCO bulk conductors and the copper electrode were obtained as 1.45 nΩ and 0.72 W, respectively in the 20 kA operation. We have demonstrated the feasibility of using a 20 kA current feedthrough for the phase II experiment of the LHD. (author)

Quantum Fluctuations of Low Dimensional Bose-Einstein ...

African Journals Online (AJOL)

Tadesse

that low dimensional quantum gases exhibit not only highly fascinating .... 2009; Marquardt and Girvin, 2009; Law, 1995; Vitali et al., 2007). ... ideal playground to test correlations between light and mesoscopic objects, to understand the.

Three-dimensional vortex pinning by nano-precipitates in a Sm-doped YBa{sub 2}Cu{sub 3}O{sub 7-x} coated conductor

Energy Technology Data Exchange (ETDEWEB)

Chen, Z [University of Wisconsin-Madison, Madison, WI 53706 (United States); Feldmann, D M [University of Wisconsin-Madison, Madison, WI 53706 (United States); Song, X [University of Wisconsin-Madison, Madison, WI 53706 (United States); Kim, S I [University of Wisconsin-Madison, Madison, WI 53706 (United States); Gurevich, A [University of Wisconsin-Madison, Madison, WI 53706 (United States); Reeves, J L [SuperPower Incorporated, 450 Duane Avenue, Schenectady, NY 12304 (United States); Xie, Y Y [SuperPower Incorporated, 450 Duane Avenue, Schenectady, NY 12304 (United States); Selvamanickam, V [SuperPower Incorporated, 450 Duane Avenue, Schenectady, NY 12304 (United States); Larbalestier, D C [University of Wisconsin-Madison, Madison, WI 53706 (United States)

2007-09-15

We report on the thickness and angular dependence of the critical current density J{sub c}(H,{theta}), the irreversibility field H{sup irr}, and the bulk pinning force F{sub p}(H) of a metal-organic chemical vapour deposition (MOCVD) grown YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) coated conductor, which contains {approx}17 vol% of {approx}10 nm sized (Y,Sm){sub 2}O{sub 3} precipitates with an average spacing of {approx}10-15 nm. Some surface porosity and amorphous second-phase particles on the scale of {approx}0.5-1 {mu}m appear to reduce the current-carrying cross-section, which controls the magnitude of J{sub c} but not the vortex pinning. We observed an enhanced H{sup irr}{approx}9 T at 77 K along the c-axis which, like the shape of J{sub c}(H) and F{sub p}(H), was independent of thickness as the sample was milled down to {approx}0.16 {mu}m. Angular-dependent measurements of J{sub c} showed the usual excess vortex pinning along the c-axis and along the ab-plane, but with a background that could only be fitted with an unusually small anisotropy parameter of 3, which, like the high H{sup irr} and the thickness-independent shape of F{sub p}(H), we ascribe to strong vortex pinning centre interactions. Together, these measurements show very different behaviour from most pulsed-laser-deposited films, which exhibit strong thickness-dependent properties. We ascribe the present different results to the dense array of small, insulating precipitates, which act as strong pinning centres and produce strong three-dimensional (3D) vortex pinning, because their separation of 10-15 nm is always much smaller than the film thickness.

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)

Influence of the structure and content of physical training tourists-conductors 12–13 years on the level of physical fitness

Directory of Open Access Journals (Sweden)

Olena Horbonos-Andronova

2015-12-01

Full Text Available Purpose: to determine the effect of the structure and content of physical training tourists-conductors 12–13 years on the level of physical fitness. Results: significant differences in the level of development of basic motor qualities tourists conductors between the experimental and control groups. Material and Methods: the used theoretical analysis and synthesis of the literature, teacher testing, methods of mathematical statistics. The study involved 90 people, 64 of them – men and 26 – women. Conclusions: determined that the overall level of physical qualities tourists conductors is low; no single structure building training process of preparation tourists conductors 12–13 years; no innovative technologies; narrow range of physical training of athletes. Established that additional means of physical training significantly affect the level of physical qualities tourists conductors 12–13 years at a stage of previous base preparation

Two level undercut-profile substrate-based filamentary coated conductors produced using metal organic chemical vapor deposition

DEFF Research Database (Denmark)

Insinga, Andrea R.; Sundaram, Aarthi; Hazelton, Drew W.

2018-01-01

The two level undercut-profile substrate (2LUPS) has been introduced as a concept for subdividing rare-earth-Ba$_{2}$Cu$_{3}$O$_{7}$ (REBCO) coated conductors (CC) into narrow filaments which reduces the AC losses and improves field stability for DC magnets. The 2LUPS consists of two levels...

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)

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)

Properties of recent IBAD-MOCVD coated conductors relevant to their high field, low temperature magnet use

Energy Technology Data Exchange (ETDEWEB)

Braccini, V; Xu, A; Jaroszynski, J; Xin, Y; Larbalestier, D C [Applied Superconductivity Center, National High Magnetic Field Laboratory, 2031 E Paul Dirac Drive, Tallahassee, FL 32310 (United States); Chen, Y; Carota, G; Dackow, J [SuperPower Inc., 450 Duane Avenue, Schenectady, NY 12304 (United States); Kesgin, I; Yao, Y; Guevara, A; Shi, T; Selvamanickam, V, E-mail: braccini@asc.magnet.fsu.edu [Department of Mechanical Engineering and the Texas Center for Superconductivity at the University of Houston, 4800 Calhoun Road, Houston, TX 77204 (United States)

2011-03-15

BaZrO{sub 3} (BZO) nanorods are now incorporated into production IBAD-MOCVD coated conductors. Here we compare several examples of both BZO-free and BZO-containing coated conductors using critical current (I{sub c}) characterizations at 4.2 K over their full angular range up to fields of 31 T. We find that BZO nanorods do not produce any c-axis distortion of the critical current density J{sub c}({theta}) curve at 4.2 K at any field, but also that pinning is nevertheless strongly enhanced compared to the non-BZO conductors. We also find that the tendency of the ab-plane J{sub c}({theta}) peak to become cusp-like is moderated by BZO and we define a new figure of merit that may be helpful for magnet design-the OADI (off-axis double I{sub c}), which clearly shows that BZO broadens the ab-plane peak and thus raises J{sub c} 5{sup 0}-30{sup 0} away from the tape plane, where the most critical approach to I{sub c} occurs in many coil designs. We describe some experimental procedures that may make critical current I{sub c} tests of these very high current tapes more tractable at 4.2 K, where I{sub c} exceeds 1000 A even for 4 mm wide tape with only 1 {mu}m thickness of superconductor. A positive conclusion is that BZO is very beneficial for the J{sub c} characteristics at 4.2 K, just as it is at higher temperatures, where the correlated c-axis pinning effects of the nanorods are much more obvious.

Scientific data interpolation with low dimensional manifold model

Science.gov (United States)

Zhu, Wei; Wang, Bao; Barnard, Richard; Hauck, Cory D.; Jenko, Frank; Osher, Stanley

2018-01-01

We propose to apply a low dimensional manifold model to scientific data interpolation from regular and irregular samplings with a significant amount of missing information. The low dimensionality of the patch manifold for general scientific data sets has been used as a regularizer in a variational formulation. The problem is solved via alternating minimization with respect to the manifold and the data set, and the Laplace-Beltrami operator in the Euler-Lagrange equation is discretized using the weighted graph Laplacian. Various scientific data sets from different fields of study are used to illustrate the performance of the proposed algorithm on data compression and interpolation from both regular and irregular samplings.

Scientific data interpolation with low dimensional manifold model

International Nuclear Information System (INIS)

Zhu, Wei; Wang, Bao; Barnard, Richard C.; Hauck, Cory D.

2017-01-01

Here, we propose to apply a low dimensional manifold model to scientific data interpolation from regular and irregular samplings with a significant amount of missing information. The low dimensionality of the patch manifold for general scientific data sets has been used as a regularizer in a variational formulation. The problem is solved via alternating minimization with respect to the manifold and the data set, and the Laplace–Beltrami operator in the Euler–Lagrange equation is discretized using the weighted graph Laplacian. Various scientific data sets from different fields of study are used to illustrate the performance of the proposed algorithm on data compression and interpolation from both regular and irregular samplings.

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)

Two-Dimensional Charge Transport in Disordered Organic Semiconductors

NARCIS (Netherlands)

Brondijk, J. J.; Roelofs, W. S. C.; Mathijssen, S. G. J.; Shehu, A.; Cramer, T.; Biscarini, F.; Blom, P. W. M.; de Leeuw, D. M.

2012-01-01

We analyze the effect of carrier confinement on the charge-transport properties of organic field-effect transistors. Confinement is achieved experimentally by the use of semiconductors of which the active layer is only one molecule thick. The two-dimensional confinement of charge carriers provides

Jordan-Wigner fermionization and the theory of low-dimensional quantum spin models

International Nuclear Information System (INIS)

Derzhko, O.

2007-01-01

The idea of mapping quantum spin lattice model onto fermionic lattice model goes back to Jordan and Wigner (1928) who transformed s = 1/2 operators which commute at different lattice sites into fermionic operators. Later on the Jordan-Wigner transformation was used for mapping one-dimensional s = 1/2 isotropic XY (XX) model onto an exactly solvable tight-binding model of spinless fermions (Lieb, Schultz and Mattis, 1961). Since that times the Jordan-Wigner transformation is known as a powerful tool in the condensed matter theory especially in the theory of low-dimensional quantum spin systems. The aim of these lectures is to review the applications of the Jordan-Wigner fermionization technique for calculating dynamic properties of low-dimensional quantum spin models. The dynamic quantities (such as dynamic structure factors or dynamic susceptibilities) are observable directly or indirectly in various experiments. The frequency and wave-vector dependence of the dynamic quantities yields valuable information about the magnetic structure of materials. Owing to a tremendous recent progress in synthesizing low-dimensional magnetic materials detailed comparisons of theoretical results with direct experimental observation are becoming possible. The lectures are organized as follows. After a brief introduction of the Jordan-Wigner transformation for one-dimensional spin one half systems and some of its extensions for higher dimensions and higher spin values we focus on the dynamic properties of several low-dimensional quantum spin models. We start from a famous s = 1/2 XX chain. As a first step we recall well-known results for dynamics of the z-spin-component fluctuation operator and then turn to dynamics of the dimer and trimer fluctuation operators. The dynamics of the trimer fluctuations involves both the two fermion (one particle and one hole) and the four-fermion (two particles and two holes) excitations. We discuss some properties of the two-fermion and four

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.

Three-dimensional charge transport in organic semiconductor single crystals.

Science.gov (United States)

He, Tao; Zhang, Xiying; Jia, Jiong; Li, Yexin; Tao, Xutang

2012-04-24

Three-dimensional charge transport anisotropy in organic semiconductor single crystals - both plates and rods (above and below, respectively, in the figure) - is measured in well-performing organic field-effect transistors for the first time. The results provide an excellent model for molecular design and device preparation that leads to good performance. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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)

Hydrogen atom trapping in a self-organized one-dimensional dimer

Directory of Open Access Journals (Sweden)

Tsuyoshi Takami

2014-09-01

Full Text Available Metal–organic frameworks (MOFs have attracted widespread attention owing to their unusual structure and properties produced by their nanospaces. However, many MOFs possess the similar three-dimensional frameworks, limiting their structural variety and operating capacity for hydrogen storage under ambient conditions. Here we report the synthesis and structural characterization of a single-crystal one-dimensional dimer whose structure, operating capacity, and physical mechanism contrast with those of existing MOFs. The hydrogen storage capacity of 2.6 wt.% is comparable to the highest capacity achieved by existing MOFs at room temperature. This exceptional storage capacity is realized by self-organization during crystal growth using a weak base.

HTS current lead units prepared by the TFA-MOD processed YBCO coated conductors

International Nuclear Information System (INIS)

Shiohara, K.; Sakai, S.; Ishii, Y.; Yamada, Y.; Tachikawa, K.; Koizumi, T.; Aoki, Y.; Hasegawa, T.; Tamura, H.; Mito, T.

2010-01-01

Two superconducting current lead units have been prepared using ten coated conductors of the Tri-Fluoro-Acetate - Metal Organic Deposition (TFA-MOD) processed Y 1 Ba 2 Cu 3 O 7-δ (YBCO) coated conductors with critical current (I c ) of about 170 A at 77 K in self-field. The coated conductors are 5 mm in width, 190 mm in length and about 120 μm in overall thickness. The 1.5 μm thick superconducting YBCO layer was synthesized through the TFA-MOD process on Hastelloy TM C-276 substrate tape with two buffer oxide layers of Gd 2 Zr 2 O 7 and CeO 2 . The five YBCO coated conductors are attached on a 1 mm thick Glass Fiber Reinforced Plastics (GFRP) board and soldered to Cu caps at the both ends. We prepared two 500 A-class current lead units. The DC transport current of 800 A was stably applied at 77 K without any voltage generation in all coated conductors. The voltage between both Cu caps linearly increased with increasing the applied current, and was about 350 μV at 500 A in both current lead units. According to the estimated values of the heat leakage from 77 K to 4.2 K, the heat leakage for the current lead unit was 46.5 mW. We successfully attained reduction of the heat leakage because of improvement of the transport current performance (I c ), a thinner Ag layer of YBCO coated conductor and usage of the GFRP board for reinforcement instead of a stainless steel board used in the previous study. The DC transport current of 1400 A was stably applied when the two current lead units were joined in parallel. The sum of the heat leakages from 77 K to 4.2 K for the combined the current lead units was 93 mW. In comparison with the conventional Cu current leads by gas-cooling, it could be noted that the heat leakage of the current lead is about one order of magnitude smaller than that of the Cu current lead.

Synthesis, Properties, and Applications of Low-Dimensional Carbon-Related Nanomaterials

Directory of Open Access Journals (Sweden)

Ali Mostofizadeh

2011-01-01

Full Text Available In recent years, many theoretical and experimental studies have been carried out to develop one of the most interesting aspects of the science and nanotechnology which is called carbon-related nanomaterials. The goal of this paper is to provide a review of some of the most exciting and important developments in the synthesis, properties, and applications of low-dimensional carbon nanomaterials. Carbon nanomaterials are formed in various structural features using several different processing methods. The synthesis techniques used to produce specific kinds of low-dimensional carbon nanomaterials such as zero-dimensional carbon nanomaterials (including fullerene, carbon-encapsulated metal nanoparticles, nanodiamond, and onion-like carbons, one-dimensional carbon nanomaterials (including carbon nanofibers and carbon nanotubes, and two-dimensional carbon nanomaterials (including graphene and carbon nanowalls are discussed in this paper. Subsequently, the paper deals with an overview of the properties of the mainly important products as well as some important applications and the future outlooks of these advanced nanomaterials.

Dynamic magneto-optical imaging of transport current redistribution and normal zone propagation in YBa2Cu3O7-δ coated conductor

International Nuclear Information System (INIS)

Song Honghai; Schwartz, Justin; Davidson, Michael W

2009-01-01

YBa 2 Cu 3 O 7-δ (YBCO) coated conductors carry high critical current density with the potential for low cost and thus have a broad range of potential applications. An unresolved issue that could inhibit implementation, however, is a lack of understanding of the current redistribution and normal zone propagation behavior in the event of a thermal disturbance (quench). In this work, we for the first time present the real-time, dynamic observation of magnetic field redistribution during a thermal disturbance via magneto-optical imaging with a high speed, high resolution CCD (charge coupled device) camera. The optical images are converted to a two-dimensional, time-dependent data set that is then analyzed quantitatively. It is found that the normal zone propagates non-uniformly in two dimensions within the YBCO layer. Two stages of normal zone propagation are observed. During the first stage, the normal zone propagates along the conductor length as the current and magnetic field redistribute within the YBCO layer. During the second stage, current sharing with the Cu begins and the magneto-optical image becomes constant. The normal zone propagation velocity at 45 K, I = 50 A (∼50% I c ), is determined as 22.7 mm s -1 using the time-dependent optical light intensity data. (rapid communication)

UST-ID robotics: Wireless communication and minimum conductor technology, and end-point tracking technology surveys

International Nuclear Information System (INIS)

Holliday, M.A.

1993-10-01

This report is a technology review of the current state-of-the-art in two technologies applicable to the Underground Storage Tank (UST) program at the Hanford Nuclear Reservation. The first review is of wireless and minimal conductor technologies for in-tank communications. The second review is of advanced concepts for independent tool-point tracking. This study addresses the need to provide wireless transmission media or minimum conductor technology for in-tank communications and robot control. At present, signals are conducted via contacting transmission media, i.e., cables. Replacing wires with radio frequencies or invisible light are commonplace in the communication industry. This technology will be evaluated for its applicability to the needs of robotics. Some of these options are radio signals, leaky coax, infrared, microwave, and optical fiber systems. Although optical fiber systems are contacting transmission media, they will be considered because of their ability to reduce the number of conductors. In this report we will identify, evaluate, and recommend the requirements for wireless and minimum conductor technology to replace the present cable system. The second section is a technology survey of concepts for independent end-point tracking (tracking the position of robot end effectors). The position of the end effector in current industrial robots is determined by computing that position from joint information, which is basically a problem of locating a point in three-dimensional space. Several approaches are presently being used in industrial robotics, including: stereo-triangulation with a theodolite network and electrocamera system, photogrammetry, and multiple-length measurement with laser interferometry and wires. The techniques that will be evaluated in this survey are advanced applications of the aforementioned approaches. These include laser tracking (3-D and 5-D), ultrasonic tracking, vision-guided servoing, and adaptive robotic visual tracking

Three-Dimensional Organization of Chromosome Territories in the Human Interphase Nucleus

NARCIS (Netherlands)

T.A. Knoch (Tobias); J. Langowski (Jörg)

1999-01-01

textabstractDespite the successful linear sequencing of the human genome its three-dimensional structure is widely unknown. The regulation of genes has been shown to be connected closely to the three-dimensional organization of the genome in the cell nucleus. The nucleus of the cell has for a long

A new cable-in-conduit conductor magnet with insulated strands

International Nuclear Information System (INIS)

Yamaguchi, Satarou; Yamamoto, Junya; Motojima, Osamu.

1995-09-01

Many studies have used cable-in-conduit conductor (CICC) coils in trying to develop an AC superconducting magnet because of its enormous potential if AC losses were low and insulation voltage was high. The strands in the most recent CICC magnets are coated with chromium or another metal with high electrical resistance to order to induce current re-distribution among the strands and to avoid a quench caused by a current imbalance. Current re-distribution is highly complex and very difficult to analyze because the conditions of the strand surfaces and the contact areas vary greatly with the operation of the conductor. If, however, the cable currents were well-balanced, insulating the strands would be the best way to reduce AC losses. We propose a new CICC magnet structure featuring a current lead that balances the strand currents via its resistance. Having calculated current balances, we find that strand currents are well within the present parameters for nuclear fusion experiments and superconducting magnet energy storages. (author)

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…

Neutron scattering studies of low dimensional magnetic systems

DEFF Research Database (Denmark)

Hansen, Ursula Bengård

investigated at low temperaturesand in a longitudinal magnetic eld using neutron spectroscopy. Here we observe thehybridisation of the magnon bound states, inherent to the low dimensional nature ofCoCl2 · 2D2O.At higher temperature, signatures which can be attributed to Magnetic Bloch Oscillationsis observed...

Local magnetic susceptibility, spin dynamics, and charge order in the quasi-one-dimensional conductor β -Li0.33V2O5 investigated by site-selective 51V NMR

Science.gov (United States)

Yamauchi, Ichihiro; Itoh, Masayuki; Yamauchi, Touru; Yamaura, Jun-Ichi; Ueda, Yutaka

2017-11-01

51V NMR measurements have been conducted on a single crystal of the quasi-one-dimensional conductor β -Li0.33V2O5 which undergoes a metal-insulator (MI) transition at TMI˜170 K. In the metallic phase, we obtain 51V Knight shift and electric field gradient tensors. From the analysis of the 51V Knight shifts, we find that the charge disproportionation appears even in the metallic state and the electronic structure is represented within a model of weakly coupled ladders containing two types of ladders with distinct carrier densities. Based on the 51V nuclear spin-lattice relaxation rate, we discuss the spin dynamics within the one-dimensional electron gas model. From the analysis of several nonmagnetic V5 + spectra observed in the insulating phase, we propose a possible charge-order pattern which has a superlattice modulation larger than those in other family members of β -A0.33V2O5 (A =Na and Ag). Finally, we discuss the A -ion dependence of the electronic structure, the charge disproportionation, and the charge order in β -A0.33V2O5 .

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.

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.

Measurement of transverse Jc profiles of coated conductors using a magnetic knife of permanent magnets

Energy Technology Data Exchange (ETDEWEB)

Haenisch, J [Los Alamos National Laboratory; Mueller, F M [Los Alamos National Laboratory; Ashworth, S P [Los Alamos National Laboratory; Coulter, J Y [Los Alamos National Laboratory; Matias, Vlad [Los Alamos National Laboratory

2008-01-01

The transverse J{sub c} distribution in YBCO coated conductors was measured non-destructively with high resolution using a 'magnetic knife' made of permanent magnets. The method utilizes the strong depression of J{sub c} in applied magnetic fields. A narrow region of low (including zero) magnetic field, in a surrounding higher field, is moved transversely across the sample in order to reveal the critical-current density distribution. The net resolution of this device is approximately 65 {micro}m, and the J{sub c} resolution is better than 0.5%. A Fourier series inversion process was used to determine the transverse J{sub c} distribution in the sample. The J{sub c} profile was correlated with other sample properties of coated conductors prepared by pulsed laser deposition. Because of its straight-forward and inexpensive design, this J{sub c} imaging technique can be a powerful tool for quality control in coated-conductor production.

Low-dimensional carbon and MXene-based electrochemical capacitor electrodes.

Science.gov (United States)

Yoon, Yeoheung; Lee, Keunsik; Lee, Hyoyoung

2016-04-29

Due to their unique structure and outstanding intrinsic physical properties such as extraordinarily high electrical conductivity, large surface area, and various chemical functionalities, low-dimension-based materials exhibit great potential for application in electrochemical capacitors (ECs). The electrical properties of electrochemical capacitors are determined by the electrode materials. Because energy charge storage is a surface process, the surface properties of the electrode materials greatly influence the electrochemical performance of the cell. Recently, graphene, a single layer of sp(2)-bonded carbon atoms arrayed into two-dimensional carbon nanomaterial, has attracted wide interest as an electrode material for electrochemical capacitor applications due to its unique properties, including a high electrical conductivity and large surface area. Several low-dimensional materials with large surface areas and high conductivity such as onion-like carbons (OLCs), carbide-derived carbons (CDCs), carbon nanotubes (CNTs), graphene, metal hydroxide, transition metal dichalcogenides (TMDs), and most recently MXene, have been developed for electrochemical capacitors. Therefore, it is useful to understand the current issues of low-dimensional materials and their device applications.

Low-dimensional carbon and MXene-based electrochemical capacitor electrodes

International Nuclear Information System (INIS)

Yoon, Yeoheung; Lee, Hyoyoung; Lee, Keunsik

2016-01-01

Due to their unique structure and outstanding intrinsic physical properties such as extraordinarily high electrical conductivity, large surface area, and various chemical functionalities, low-dimension-based materials exhibit great potential for application in electrochemical capacitors (ECs). The electrical properties of electrochemical capacitors are determined by the electrode materials. Because energy charge storage is a surface process, the surface properties of the electrode materials greatly influence the electrochemical performance of the cell. Recently, graphene, a single layer of sp 2 -bonded carbon atoms arrayed into two-dimensional carbon nanomaterial, has attracted wide interest as an electrode material for electrochemical capacitor applications due to its unique properties, including a high electrical conductivity and large surface area. Several low-dimensional materials with large surface areas and high conductivity such as onion-like carbons (OLCs), carbide-derived carbons (CDCs), carbon nanotubes (CNTs), graphene, metal hydroxide, transition metal dichalcogenides (TMDs), and most recently MXene, have been developed for electrochemical capacitors. Therefore, it is useful to understand the current issues of low-dimensional materials and their device applications. (topical review)

Workshop on low-dimensional quantum field theory and its applications

International Nuclear Information System (INIS)

Yamamoto, Hisashi

1990-02-01

The workshop on 'Low-Dimensional Quantum Field Theory and its Applications' was held at INS on December 18 - 20, 1989 with about seventy participants. Some pedagogical reviews and the latest results were delivered on the recent topics related to both solid-state and particle physics. Among them are quantum Hall effect, high T c superconductivity and related topics in low-dimensional quantum field theory. Many active discussions were made on these issues. (J.P.N.)

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...

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

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.

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.

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.

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.

A New Generation of Luminescent Materials Based on Low-Dimensional Perovskites

KAUST Repository

Pan, Jun

2017-06-02

Low-dimensional perovskites with high luminescence properties are promising materials for optoelectronic applications. In this article, properties of two emerging types of low-dimensional perovskites are discussed, including perovskite quantum dots CsPbX3 (X = Cl, Br or I) and zero-dimensional perovskite Cs4PbBr6. Moreover, their application for light down conversion in LCD backlighting systems and in visible light communication are also presented. With their superior optical properties, we believe that further development of these materials will potentially open more prospective applications, especially for optoelectronics devices.

A Nanophase-Separated, Quasi-Solid-State Polymeric Single-Ion Conductor: Polysulfide Exclusion for Lithium–Sulfur Batteries

Energy Technology Data Exchange (ETDEWEB)

Lee, Jinhong; Song, Jongchan; Lee, Hongkyung; Noh, Hyungjun; Kim, Yun-Jung; Kwon, Sung Hyun; Lee, Seung Geol; Kim, Hee-Tak

2017-04-19

Formation of soluble polysulfide (PS), which is a key feature of lithium sulfur (Li–S) batteries, provides a fast redox kinetic based on a liquid–solid mechanism; however, it imposes the critical problem of PS shuttle. Here, we address the dilemma by exploiting a solvent-swollen polymeric single-ion conductor (SPSIC) as the electrolyte medium of the Li–S battery. The SPSIC consisting of a polymeric single-ion conductor and lithium salt-free organic solvents provides Li ion hopping by forming a nanoscale conducting channel and suppresses PS shuttle according to the Donnan exclusion principle when being employed for Li–S batteries. The organic solvents at the interface of the sulfur/carbon composite and SPSIC eliminate the poor interfacial contact and function as a soluble PS reservoir for maintaining the liquid–solid mechanism. Furthermore, the quasi-solid-state SPSIC allows the fabrication of a bipolar-type stack, which promises the realization of a high-voltage and energy-dense Li–S battery.

Magnetization measurements on multifilamentary Nb3Sn and NbTi conductors

International Nuclear Information System (INIS)

Ghosh, A.K.; Robins, K.E.; Sampson, W.B.

1984-01-01

The effective filament size has been determined for a number of high current Nb 3 Sn multifilamentary composites. In most cases it is much larger than the nominal filament size. For the smallest filaments (approx. 1 micron) the effective size can be as much as a factor of forty times the nominal size. Samples made by the internal tin, bronze route, and jelly roll methods have been examined with filaments in the range one to ten microns. Rate dependent magnetization and flux jumping have been observed in some cases. NbTi composites ranging in filament size from nine to two hundred microns and with copper to super-conductor ratios between 1.6:1 and 7:1 have been examined in the same apparatus. Low field flux jumping was only observed in conductors with very large filaments and relatively little stabilizing copper. 9 references, 6 figures, 3 tables

The three-dimensional genome organization of Drosophila melanogaster through data integration.

Science.gov (United States)

Li, Qingjiao; Tjong, Harianto; Li, Xiao; Gong, Ke; Zhou, Xianghong Jasmine; Chiolo, Irene; Alber, Frank

2017-07-31

Genome structures are dynamic and non-randomly organized in the nucleus of higher eukaryotes. To maximize the accuracy and coverage of three-dimensional genome structural models, it is important to integrate all available sources of experimental information about a genome's organization. It remains a major challenge to integrate such data from various complementary experimental methods. Here, we present an approach for data integration to determine a population of complete three-dimensional genome structures that are statistically consistent with data from both genome-wide chromosome conformation capture (Hi-C) and lamina-DamID experiments. Our structures resolve the genome at the resolution of topological domains, and reproduce simultaneously both sets of experimental data. Importantly, this data deconvolution framework allows for structural heterogeneity between cells, and hence accounts for the expected plasticity of genome structures. As a case study we choose Drosophila melanogaster embryonic cells, for which both data types are available. Our three-dimensional genome structures have strong predictive power for structural features not directly visible in the initial data sets, and reproduce experimental hallmarks of the D. melanogaster genome organization from independent and our own imaging experiments. Also they reveal a number of new insights about genome organization and its functional relevance, including the preferred locations of heterochromatic satellites of different chromosomes, and observations about homologous pairing that cannot be directly observed in the original Hi-C or lamina-DamID data. Our approach allows systematic integration of Hi-C and lamina-DamID data for complete three-dimensional genome structure calculation, while also explicitly considering genome structural variability.

On the electrical contact and long-term behavior of compression-type connections with conventional and high-temperature conductor ropes with low sag; Zum elektrischen Kontakt- und Langzeitverhalten von Pressverbindungen mit konventionellen und Hochtemperatur-Leiterseilen mit geringem Durchhang

Energy Technology Data Exchange (ETDEWEB)

Hildmann, Christian

2016-12-09

In Germany and in Europe it is due to the ''Energiewende'' necessary to transmit more electrical energy with existing overhead transmission lines. One possible technical solution to reach this aim is the use of high temperature low sag conductors (HTLS-conductors). Compared to the common Aluminium Conductor Steel Reinforced (ACSR), HTLS-conductors have higher rated currents and rated temperatures. Thus the electrical connections for HTLS-conductors are stressed to higher temperatures too. These components are most important for the safe and reliable operation of an overhead transmission line. Besides other connection technologies, hexagonal compression connections with ordinary transmission line conductors have proven themselves since decades. From the literature, mostly empirical studies with electrical tests for compression connections are known. The electrical contact behaviour, i.e. the quality of the electrical contact after assembly, of these connections has been investigated insufficiently. This work presents and enhances an electrical model of compression connections, so that the electrical contact behaviour can be determined more accurate. Based on this, principal considerations on the current distribution in the compression connection and its influence on the connection resistance are presented. As a result from the theoretical and the experimental work, recommendations for the design of hexagonal compression connections for transmission line conductors were developed. Furthermore it is known from the functional principle of compression type connections, that the electrical contact behaviour can be influenced from their form fit, force fit and cold welding. In particular the forces in compression connections have been calculated up to now by approximation. The known analytical calculations simplify the geometry and material behaviour and do not consider the correct mechanical load during assembly. For these reasons the joining process

Fabrication of 100 A class, 1 m long coated conductor tapes by metal organic chemical vapor deposition and pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Selvamanickam, V.; Lee, H.G.; Li, Y.; Xiong, X.; Qiao, Y.; Reeves, J.; Xie, Y.; Knoll, A.; Lenseth, K

2003-10-15

SuperPower has been scaling up YBa{sub 2}Cu{sub 3}O{sub x}-based second-generation superconducting tapes by techniques such as pulsed laser deposition (PLD) using industrial laser and metal organic chemical vapor deposition (MOCVD). Both techniques offer advantage of high deposition rates, which is important for high throughput. Using highly-polished substrates produced in a reel-to-reel polishing facility and buffer layers deposited in a pilot ion beam assisted deposition facility, meter-long second-generation high temperature superconductor tapes have been produced. 100 A class, meter-long coated conductor tapes have been reproducibly demonstrated in this work by both MOCVD and PLD. The best results to date are 148 A over 1.06 m by MOCVD and 135 A over 1.1 m by PLD using industrial laser.

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.

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)

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.

Low dimensional neutron moderators for enhanced source brightness

DEFF Research Database (Denmark)

Mezei, Ferenc; Zanini, Luca; Takibayev, Alan

2014-01-01

In a recent numerical optimization study we have found that liquid para-hydrogen coupled cold neutron moderators deliver 3–5 times higher cold neutron brightness at a spallation neutron source if they take the form of a flat, quasi 2-dimensional disc, in contrast to the conventional more voluminous...... for cold neutrons. This model leads to the conclusions that the optimal shape for high brightness para-hydrogen neutron moderators is the quasi 1-dimensional tube and these low dimensional moderators can also deliver much enhanced cold neutron brightness in fission reactor neutron sources, compared...... to the much more voluminous liquid D2 or H2 moderators currently used. Neutronic simulation calculations confirm both of these theoretical conclusions....

Three-Dimensional Organization of Chromosome Territories and the Human Cell Nucleus

NARCIS (Netherlands)

T.A. Knoch (Tobias)

1999-01-01

textabstractTo study the three-dimensional organization of chromosome territories and the human interphase cell nucleus we developed models, which could be compared to experiments. Despite the successful linear sequencing of the human genome its 3D-organization is widely unknown. Using Monte

Low-Threshold Lasing from 2D Homologous Organic-Inorganic Hybrid Ruddlesden-Popper Perovskite Single Crystals.

Science.gov (United States)

Raghavan, Chinnambedu Murugesan; Chen, Tzu-Pei; Li, Shao-Sian; Chen, Wei-Liang; Lo, Chao-Yuan; Liao, Yu-Ming; Haider, Golam; Lin, Cheng-Chieh; Chen, Chia-Chun; Sankar, Raman; Chang, Yu-Ming; Chou, Fang-Cheng; Chen, Chun-Wei

2018-05-09

Organic-inorganic hybrid two-dimensional (2D) perovskites have recently attracted great attention in optical and optoelectronic applications due to their inherent natural quantum-well structure. We report the growth of high-quality millimeter-sized single crystals belonging to homologous two-dimensional (2D) hybrid organic-inorganic Ruddelsden-Popper perovskites (RPPs) of (BA) 2 (MA) n-1 Pb n I 3 n+1 ( n = 1, 2, and 3) by a slow evaporation at a constant-temperature (SECT) solution-growth strategy. The as-grown 2D hybrid perovskite single crystals exhibit excellent crystallinity, phase purity, and spectral uniformity. Low-threshold lasing behaviors with different emission wavelengths at room temperature have been observed from the homologous 2D hybrid RPP single crystals. Our result demonstrates that solution-growth homologous organic-inorganic hybrid 2D perovskite single crystals open up a new window as a promising candidate for optical gain media.

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.

Stranski–Krastanov transition and self-organized structures in low-strained AlInN/GaN multilayer structures

International Nuclear Information System (INIS)

Krost, A; Berger, C; Moser, P; Bläsing, J; Dadgar, A; Hums, C; Hempel, T; Bastek, B; Veit, P; Christen, J

2011-01-01

Low-strained AlInN/GaN multilayers aimed as Bragg mirrors were grown by metal organic vapour phase epitaxy on GaN/Si(1 1 1). In such structures the upper AlInN/GaN interfaces show a considerable roughening on a nanometre scale whereas the lower ones appear flat as evaluated by cross-sectional electron and transmission electron microscopy. The roughening is attributed to a Stranski–Krastanov transition from two-dimensional layer-by-layer to three-dimensional island growth. In addition, a self-organized wavy-like surface morphology on a micrometre scale is observed in such structures which we discuss in terms of Grinfeld instability

Low dimensional field theories and condensed matter physics

International Nuclear Information System (INIS)

Nagaoka, Yosuke

1992-01-01

This issue is devoted to the Proceedings of the Fourth Yukawa International Seminar (YKIS '91) on Low Dimensional Field Theories and Condensed Matter Physics, which was held on July 28 to August 3 in Kyoto. In recent years there have been great experimental discoveries in the field of condensed matter physics: the quantum Hall effect and the high temperature superconductivity. Theoretical effort to clarify mechanisms of these phenomena revealed that they are deeply related to the basic problem of many-body systems with strong correlation. On the other hand, there have been important developments in field theory in low dimensions: the conformal field theory, the Chern-Simons gauge theory, etc. It was found that these theories work as a powerful method of approach to the problems in condensed matter physics. YKIS '91 was devoted to the study of common problems in low dimensional field theories and condensed matter physics. The 17 of the presented papers are collected in this issue. (J.P.N.)

Investigation and optimization of YBa2Cu3O7-δ grain boundaries and coated conductors

International Nuclear Information System (INIS)

Held, Rainer Robert Martin

2010-01-01

With increasing misorientation angle grain boundaries strongly reduce the critical current density of high temperature superconductors. For this reason costly techniques are used in production of modern Coated Conductors to induce sharp textures in the polycrystalline superconductor layers. In this dissertation measurements of the critical current density of different grain boundary types are presented showing that out-of-plane grain boundaries exhibit, also in applied magnetic fields, much higher critical current densities than expected. In further analysis of the grain boundaries indications for a microstructural reason of the high critical current densities were found. The high critical current densities of the out-of-plane grain boundaries should in fabrication of Coated Conductors allow for a relaxation of the out-of-plane grain alignment requirements and a concomitant cost reduction. In this work also results of a industrial cooperation with Nexans are presented demonstrating that the critical current density of metal-organic deposited grain boundaries and Coated Conductor layers can be increased by selective Calcium-doping. In the experiments selective Calcium-doping most effectively increased the critical current density of weak spots. (orig.)

Quantum Effects in the Thermoelectric Power Factor of Low-Dimensional Semiconductors.

Science.gov (United States)

Hung, Nguyen T; Hasdeo, Eddwi H; Nugraha, Ahmad R T; Dresselhaus, Mildred S; Saito, Riichiro

2016-07-15

We theoretically investigate the interplay between the confinement length L and the thermal de Broglie wavelength Λ to optimize the thermoelectric power factor of semiconducting materials. An analytical formula for the power factor is derived based on the one-band model assuming nondegenerate semiconductors to describe quantum effects on the power factor of the low-dimensional semiconductors. The power factor is enhanced for one- and two-dimensional semiconductors when L is smaller than Λ of the semiconductors. In this case, the low-dimensional semiconductors having L smaller than their Λ will give a better thermoelectric performance compared to their bulk counterpart. On the other hand, when L is larger than Λ, bulk semiconductors may give a higher power factor compared to the lower dimensional ones.

A study of low-dimensional inhomogeneous systems

International Nuclear Information System (INIS)

Arredondo Leon, Yesenia

2009-01-01

While the properties of homogeneous one-dimensional systems, even with disorder, are relatively well-understood, very little is known about the properties of strongly interacting inhomogeneous systems. Their high-energy physics is determined by the underlying chemistry which, in the atomic scale, introduces Coulomb correlations and local potentials. On the other hand, at large length scales, the physics has to be described by the Tomonaga-Luttinger liquid (TLL) model. In order to establish a connection between the low-energy TLL and the quasi-one-dimensional systems synthesized in the laboratory, we investigate the density-density correlation function in inhomogeneous one-dimensional systems in the asymptotic region. To investigate homogeneous as well as inhomogeneous systems, we use the density-matrix renormalization group (DMRG) method. We present results for ground state properties, such as the density-density correlation function and the parameter K c , which characterizes its decay at large distances. (orig.)

A study of low-dimensional inhomogeneous systems

Energy Technology Data Exchange (ETDEWEB)

Arredondo Leon, Yesenia

2009-01-15

While the properties of homogeneous one-dimensional systems, even with disorder, are relatively well-understood, very little is known about the properties of strongly interacting inhomogeneous systems. Their high-energy physics is determined by the underlying chemistry which, in the atomic scale, introduces Coulomb correlations and local potentials. On the other hand, at large length scales, the physics has to be described by the Tomonaga-Luttinger liquid (TLL) model. In order to establish a connection between the low-energy TLL and the quasi-one-dimensional systems synthesized in the laboratory, we investigate the density-density correlation function in inhomogeneous one-dimensional systems in the asymptotic region. To investigate homogeneous as well as inhomogeneous systems, we use the density-matrix renormalization group (DMRG) method. We present results for ground state properties, such as the density-density correlation function and the parameter K{sub c}, which characterizes its decay at large distances. (orig.)

Uniaxial strain effects on transport properties of a supramolecular organic conductor theta-(DIETS) sub 2 [Au(CN) sub 4

CERN Document Server

Tajima, N; Kato, R; Nishio, Y; Kajita, K

2003-01-01

Pressure-controlled switching between an insulating state and a superconducting state has been successfully realized on a supramolecular organic conductor theta-(DIETS) sub 2 [Au(CN) sub 4] [DIETS = diiodo(ethylenedithio)diselenadithiafulvalene]. Strong contact between iodine on the donor (DIETS) molecule and nitrogen on the anion [Au(CN) sub 4] genetates characteristic uniaxial strain effects on transport properties. Under the ambient pressure, the present system undergoes a semiconductor-insulator transition at 226 K. The effect of strains parallel to the conduction plane (ab-plane) is very small. Even under uniaxial strains up to 20 kbar along the a- and b-axis directions, the transition is not suppressed. Surprisingly, however, the c-axis strain induces a superconducting state with T sub c of 8.6 K at 10 kbar. Band parameter calculation and the conductivity anisotropy ratio suggest that an increase in the bandwidth W associated with a c-axis strain transforms the system to the metallic and superconducting...

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.

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.

Are low-dimensional dynamics typical in magnetically confined plasmas?

International Nuclear Information System (INIS)

Ball, R.; Dewar, R.L.

2000-01-01

Full text: Since 1988 there have been many serious attempts to construct low-dimensional dynamical systems that model L-H transitions and associated oscillatory phenomena in magnetically confined plasmas. Such models usually consist of coupled ordinary differential equations in a few dynamical state variables and several parameters that represent physical properties or external controls. The advantages of a unified, low-dimensional approach to modelling plasma behaviour are multifold. Most importantly, the qualitative analysis of nonlinear ODE and algebraic systems is supported by a substantial body of theory. The toolkits of singularity and stability theory are well-developed and accessible, and contain the right tools for the job of charting the state and parameter space. One of the driving forces behind the development of low-dimensional dynamical models is the predictive potential of a parameter map. For example, a model that talks of the shape and extent of hysteresis in the L-H transition would help engineers who are interested in controlling access to H-mode. We can express this problem another way: given the enormous number of variables and parameters that could be varied around a hysteretic regime, it would be cheaper to know in advance which ones actually do influence the quality and quantity of the hysteresis. The quest for a low-dimensional state space that contains the qualitative dynamics of L-H transitions also introduces other problems. We need to identify the essential (few) dynamical variables and the essential (few) independent parameter groups, clarify the mechanisms for the feedback that is modelled by nonlinear terms, and identify symmetries in the physics. Before jumping the gun on these questions the fundamental issue should be addressed of whether a confined plasma, having many important length and time scales, steep gradients, strong anisotropy, and an uncountable multiplicity of states, can indeed exhibit low-dimensional dynamics. In this

Angular dependence of J{sub c} for YBCO coated conductors at low temperature and very high magnetic fields

Energy Technology Data Exchange (ETDEWEB)

Xu, A; Jaroszynski, J J; Kametani, F; Chen, Z; Larbalestier, D C [Applied Superconductivity Center, National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310 (United States); Viouchkov, Y L [National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310 (United States); Chen, Y; Xie, Y; Selvamanickam, V, E-mail: aixiaxu@asc.magnet.fsu.ed [SuperPower Incorporated, 450 Duane Avenue, Schenectady, NY 12304 (United States)

2010-01-15

We present very high field angle dependent critical current density (J{sub c}) data for three recently obtained YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) coated conductors used in the construction of high field solenoids. We find that strongly correlated pins, such as BaZrO{sub 3} (BZO) nanorods, while yielding strong c-axis peaks at 77 K, produce almost no measurable contribution at 4 K. Raising the field from <5 to 30 T at 4 K causes a marked transition from a Ginzburg-Landau-like J{sub c}({theta}) at low fields to a marked cusp-like behavior at high fields. Transmission electron micrographs show that all samples contain a high density of stacking faults which strengthen the plane correlated pinning parallel to the ab planes produced by the intrinsic ab-plane pinning of the Cu-O charge reservoir layers.

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

Density-matrix renormalization group method for the conductance of one-dimensional correlated systems using the Kubo formula

Science.gov (United States)

Bischoff, Jan-Moritz; Jeckelmann, Eric

2017-11-01

We improve the density-matrix renormalization group (DMRG) evaluation of the Kubo formula for the zero-temperature linear conductance of one-dimensional correlated systems. The dynamical DMRG is used to compute the linear response of a finite system to an applied ac source-drain voltage; then the low-frequency finite-system response is extrapolated to the thermodynamic limit to obtain the dc conductance of an infinite system. The method is demonstrated on the one-dimensional spinless fermion model at half filling. Our method is able to replicate several predictions of the Luttinger liquid theory such as the renormalization of the conductance in a homogeneous conductor, the universal effects of a single barrier, and the resonant tunneling through a double barrier.

Progress in scale-up of second-generation HTS conductor

International Nuclear Information System (INIS)

Selvamanickam, V.; Chen, Y.; Xiong, X.; Xie, Y.; Zhang, X.; Qiao, Y.; Reeves, J.; Rar, A.; Schmidt, R.; Lenseth, K.

2007-01-01

Tremendous progress has been recently made in the achievement of high-performance, high-speed, long-length second-generation (2G) HTS conductors. Using ion beam assisted deposition (IBAD) MgO and metal organic chemical vapor deposition (MOCVD), SuperPower has scaled up tape lengths to 427 m with a minimum critical current value of 191 A/cm corresponding to a critical current x length performance of 81,550 m. Tape speeds up to 120 m/h have been reached with IBAD MgO, up to 80 m/h with buffer deposition and up to 45 m/h with MOCVD, all in single pass processing of 12 mm wide tape. Critical current value of 227 A/cm has been achieved in a 203 m long tape produced in an all-high-speed fabrication process. Critical current values have been raised to 721 A/cm, 592 A/cm and 486 A/cm in short, reel-to-reel processed tape, over 1 m length and over 11.1 m, respectively, using thicker MOCVD HTS films. Finally, over 10,000 m of copper-stabilized, 4 mm wide conductor has been produced and tested for delivery to the Albany Cable project. The average critical current of the 10,000 m lot was 81 A

Progress in scale-up of second-generation HTS conductor

Energy Technology Data Exchange (ETDEWEB)

Selvamanickam, V. [SuperPower Inc., 450 Duane Avenue, Schenectady, NY 12304 (United States)], E-mail: vselva@igc.com; Chen, Y.; Xiong, X.; Xie, Y.; Zhang, X.; Qiao, Y.; Reeves, J.; Rar, A.; Schmidt, R.; Lenseth, K. [SuperPower Inc., 450 Duane Avenue, Schenectady, NY 12304 (United States)

2007-10-01

Tremendous progress has been recently made in the achievement of high-performance, high-speed, long-length second-generation (2G) HTS conductors. Using ion beam assisted deposition (IBAD) MgO and metal organic chemical vapor deposition (MOCVD), SuperPower has scaled up tape lengths to 427 m with a minimum critical current value of 191 A/cm corresponding to a critical current x length performance of 81,550 m. Tape speeds up to 120 m/h have been reached with IBAD MgO, up to 80 m/h with buffer deposition and up to 45 m/h with MOCVD, all in single pass processing of 12 mm wide tape. Critical current value of 227 A/cm has been achieved in a 203 m long tape produced in an all-high-speed fabrication process. Critical current values have been raised to 721 A/cm, 592 A/cm and 486 A/cm in short, reel-to-reel processed tape, over 1 m length and over 11.1 m, respectively, using thicker MOCVD HTS films. Finally, over 10,000 m of copper-stabilized, 4 mm wide conductor has been produced and tested for delivery to the Albany Cable project. The average critical current of the 10,000 m lot was 81 A.

Design and implementation of low profile antenna for dual-band applications using rotated e-shaped conductor-backed plane.

Science.gov (United States)

Jalali, Mahdi; Sedghi, Tohid; Shafei, Shahin

2014-01-01

A novel configuration of a printed monopole antenna with a very compact size for satisfying WLAN operations at the 5.2/5.8 GHz and also for X-band operations at the 10 GHz has been proposed. The antenna includes a simple square-shaped patch as the radiator, the rotated U-shaped conductor back plane element with embedded strip on it, and the partial rectangular ground surface. By using the rotated U-shaped conductor-backed plane with proper values, good impedance matching and improvement in bandwidth can be achieved, at the lower and upper bands. The impedance bandwidth for S11 WLAN-band and 4.2 dBi at X-band. The experimental results represent that the realized antenna with good omnidirectional radiation characteristics, enough impedance bandwidth, and reasonable gains can be appropriate for various applications of the future developed technologies and handheld devices.

Magnetic levitation by induced eddy currents in non-magnetic conductors and conductivity measurements

International Nuclear Information System (INIS)

Iniguez, J; Raposo, V; Flores, A G; Zazo, M; Hernandez-Lopez, A

2005-01-01

We report a study on magnetic levitation by induced ac currents in non-magnetic conductors at low frequencies. Our discussion, based on Faraday's induction law, allows us to distinguish the two components of the current responsible for levitation and heating, respectively. The experimental evaluation of the levitation force in a copper ring revealed the accuracy of our analysis, clearly illustrating its asymptotic behaviour versus frequency, and validating it for the qualitative analysis of magnetic levitation and heating in conductors of different shapes such as tubes and discs, composed of collections of conductive loops. The analysis of the results allows precise values of its electrical conductivity to be found. With the help of a simulation technique, this work also reveals the progressive deformation undergone by magnetic induction lines due to magnetic screening when frequency increases

Approaching the Sequential and Three-Dimensional Organization of Genomes

NARCIS (Netherlands)

T.A. Knoch (Tobias)

2006-01-01

textabstractGenomes are one of the major foundations of life due to their role in information storage, process regulation and evolution. To achieve a deeper unterstanding of the human genome the three-dimensional organization of the human cell nucleus, the structural-, scaling- and dynamic

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...

Approaching the sequential and three-dimensional organization of Archaea, Bacteria and Eukarya genomes. Dynamic Organization of Nuclear Function

NARCIS (Netherlands)

T.A. Knoch (Tobias); M. Göker (Markus); R. Lohner (Rudolf); J. Langowski (Jörg)

2002-01-01

textabstractThe largely unresolved sequential organization, i.e. the relations within DNA sequences, and its connection to the three-dimensional organization of genomes was investigated by correlation analyses of completely sequenced chromosomes from Viroids, Archaea, Bacteria, Arabidopsis

Organic Semiconductors and Conductors with tert-Butyl Substituents

Directory of Open Access Journals (Sweden)

Toshiki Higashino

2012-08-01

Full Text Available Tetrathiafulvalene (TTF, pentacene, and quarterthiophene with tert-butyl substituents are synthesized, and the crystal structures and the transistor properties are investigated. The tetracyanoquinodimethane (TCNQ complex of tert-butyl TTF constructs highly one-dimensional segregated columns with tetragonal crystal symmetry.

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.

PREFACE: Dynamics of low-dimensional systems Dynamics of low-dimensional systems

Science.gov (United States)

Bernasconi, M.; Miret-Artés, S.; Toennies, J. P.

2012-03-01

With the development of techniques for high-resolution inelastic helium atom scattering (HAS), electron scattering (EELS) and neutron spin echo spectroscopy, it has become possible, within approximately the last thirty years, to measure the dispersion curves of surface phonons in insulators, semiconductors and metals. In recent years, the advent of new experimental techniques such as 3He spin-echo spectroscopy, scanning inelastic electron tunnel spectroscopy, inelastic x-ray scattering spectroscopy and inelastic photoemission have extended surface phonon spectroscopy to a variety of systems. These include ultra-thin metal films, adsorbates at surface and elementary processes where surface phonons play an important role. Other important directions have been actively pursued in the past decade: the dynamics of stepped surfaces and clusters grown on metal surfaces, due to their relevance in many dynamical and chemical processes at surfaces, including heterogeneous catalysis; clusters; diffusion etc. The role of surface effects in these processes has been conjectured since the early days of surface dynamics, although only now is the availability of ab initio approaches providing those conjectures with a microscopic basis. Last but not least, the investigation of non-adiabatic effects, originating for instance from the hybridization (avoided crossing) of the surface phonons branches with the quasi 1D electron-hole excitation branch, is also a challenging new direction. Furthermore, other elementary oscillations such as surface plasmons are being actively investigated. The aforementioned experimental breakthroughs have been accompanied by advances in the theoretical study of atom-surface interaction. In particular, in the past decade first principles calculations based on density functional perturbation theory have boosted the theoretical study of the dynamics of low-dimensional systems. Phonon dispersion relations of clean surfaces, the dynamics of adsorbates, and the

Performance of coils wound from long lengths of surface-coated, reacted, BSCCO-2212 conductor

Energy Technology Data Exchange (ETDEWEB)

Walker, M.S.; Hazelton, D.W.; Gardner, M.T. [Intermagnetics General Corp., Latham, NY (United States)] [and others

1996-10-01

React-before-wind surface-coated BSCCO-2212 is being established as a relatively low cost HTS conductor for practical applications. Quality tape is presently being manufactured in 450-500m lengths at a cost estimated to be 1/3-1/5 of the industry costs of BSCCO-2223 powder-in-tube tape. Robust, mechanically sound coils for applications ranging from NMR insert magnets to transformer windings are being made from this BSCCO-2212 tape. The coils have performed consistently through test and thermal cycling without degradation and as projected from short sample measurements. A hybrid approach, which uses mainly BSCCO- 2212 augmented by BSCCO-2223 conductor in the high radial field end regions, is expected to halve magnet system costs.

Critical current survival in the YBCO superconducting layer of a delaminated coated conductor

Science.gov (United States)

Feng, Feng; Fu, Qishu; Qu, Timing; Mu, Hui; Gu, Chen; Yue, Yubin; Wang, Linli; Yang, Zhirong; Han, Zhenghe; Feng, Pingfa

2018-04-01

A high-temperature superconducting coated conductor can be practically applied in electric equipment due to its favorable mechanical properties and critical current (I c) performance. However, the coated conductor can easily delaminate because of its poor stress tolerance along the thickness direction. It would be interesting to investigate whether the I c of the delaminated YBa2Cu3O7-δ (YBCO) layer can be preserved. In this study, coated conductor samples manufactured through the metal organic deposition route were delaminated by liquid nitrogen immersion. Delaminated samples, including the YBCO layer and silver stabilizer, were obtained. Delamination occurred inside the YBCO layer and near the YBCO-CeO2 interface, as suggested by the results of scanning electron microscopy (SEM) and x-ray diffraction. A scanning Hall probe system was employed to measure the I c distribution of the original sample and the delaminated sample. It was found that approximately 50% of the I c can be preserved after delamination, which was verified by I c measurements using the four-probe method. Dense and crack-free morphologies of the delaminated surfaces were observed by SEM, which accounts for the I c survival of the delaminated YBCO layer. The potential application of the delaminated sample in superconducting joints was discussed based on the oxygen diffusion estimation.

AC Loss Reduction in Filamentized YBCO Coated Conductors with Virtual Transverse Cross-cuts

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yifei [ORNL; Duckworth, Robert C [ORNL; Ha, Tam T [ORNL; List III, Frederick Alyious [ORNL; Gouge, Michael J [ORNL; Chen, Y [SuperPower Incorporated, Schenectady, New York; X, Xiong, [SuperPower Incorporated, Schenectady, New York; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York

2011-01-01

While the performance of YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO)-based coated conductors under dc currents has improved significantly in recent years, filamentization is being investigated as a technique to reduce ac loss so that the 2nd generation (2G) high temperature superconducting (HTS) wires can also be utilized in various ac power applications such as cables, transformers and fault current limiters. Experimental studies have shown that simply filamentizing the superconducting layer is not effective enough to reduce ac loss because of incomplete flux penetration in between the filaments as the length of the tape increases. To introduce flux penetration in between the filaments more uniformly and further reduce the ac loss, virtual transverse cross-cuts were made in superconducting filaments of the coated conductors fabricated using the metal organic chemical vapor deposition (MOCVD) method. The virtual transverse cross-cuts were formed by making cross-cuts (17 - 120 {micro}m wide) on the IBAD (ion beam assisted deposition)-MgO templates using laser scribing followed by depositing the superconducting layer ({approx} 0.6 {micro}m thick). AC losses were measured and compared for filamentized conductors with and without the cross-cuts under applied peak ac fields up to 100 mT. The results were analyzed to evaluate the efficacy of filament decoupling and the feasibility of using this method to achieve ac loss reduction.

Measurement and Analysis of Normal Zone Propagation in a ReBCO Coated Conductor at Temperatures Below 50K

CERN Document Server

van Nugteren, J; Wessel, S; Krooshoop, E; Nijhuis, A; ten Kate, H

2015-01-01

Measurements of the quasi-adiabatic normal zone propagation velocity and quench energies of a Superpower SCS4050 copper stabilised ReBCO superconducting tape are presented over a temperature range of 23 − 47 K; in parallel applied magnetic fields of 6, 10 and 14 T; and over a current range from 50% to 100% of Ic. The data are compared to results of analytic predictions and to one-dimensional numerical simulations. The availability of long lengths of ReBCO coated conductor makes the material interesting for many HTS applications operating well below the boiling point of liquid nitrogen, such as magnets and motors. One of the main issues in the design of such devices is quench detection and protection. At higher temperatures, the quench velocities in these materials are known to be about two orders of magnitude lower compared to low temperature superconductors, resulting in significantly smaller normal zones and the risk of higher peak temperatures. To investigate whether the same also holds for lower tempera...

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.)

Low-dimensional filiform Lie algebras over finite fields

OpenAIRE

Falcón Ganfornina, Óscar Jesús; Núñez Valdés, Juan; Pacheco Martínez, Ana María; Villar Liñán, María Trinidad; Vasek, Vladimir (Coordinador); Shmaliy, Yuriy S. (Coordinador); Trcek, Denis (Coordinador); Kobayashi, Nobuhiko P. (Coordinador); Choras, Ryszard S. (Coordinador); Klos, Zbigniew (Coordinador)

2011-01-01

In this paper we use some objects of Graph Theory to classify low-dimensional filiform Lie algebras over finite fields. The idea lies in the representation of each Lie algebra by a certain type of graphs. Then, some properties on Graph Theory make easier to classify the algebras. As results, which can be applied in several branches of Physics or Engineering, for instance, we find out that there exist, up to isomorphism, six 6-dimensional filiform Lie algebras over Z/pZ, for p = 2, 3, 5. Pl...

NATO Advanced Research Workshop on Physicochemical Properties of Zeolitic Systems and Their Low Dimensionality

CERN Document Server

Derouane, Eric; Hölderich, Wolfgang

1990-01-01

Low dimensionality is a multifarious concept which applies to very diversified materials. Thus, examples of low-dimensional systems are structures with one or several layers, single lines or patterns of lines, and small clusters isolated or dispersed in solid systems. Such low­ dimensional features can be produced in a wide variety of materials systems with a broad spectrum of scientific and practical interests. These features, in turn, induce specific properties and, particularly, specific transport properties. In the case of zeolites, low dimensionality appears in the network of small-diameter pores of molecular size, extending in one, two or three di­ mensions, that these solids exhibit as a characteristic feature and which explains the term of "molecular sieves" currently used to name these ma­ terials. Indeed, a large number of industrial processes for separation of gases and liquids, and for catalysis are based upon the use of this low­ dimensional feature in zeolites. For instance, zeolites constit...

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...

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

Self-organization processes and nanocluster formation in crystal lattices by low-energy ion irradiation

International Nuclear Information System (INIS)

Tereshko, I.; Abidzina, V.; Tereshko, A.; Glushchenko, V.; Elkin, I.

2007-01-01

The goal of this paper is to study self-organization processes that cause nanostructural evolution in nonlinear crystal media. The subjects of the investigation were nonlinear homogeneous and heterogeneous atom chains. The method of computer simulation was used to investigate the interaction between low-energy ions and crystal lattices. It was based on the conception of three-dimensional lattice as a nonlinear atom chain system. We showed that that in homogeneous atom chains critical energy needed for self-organization processes development is less than for nonlinear atom chain with already embedded clusters. The possibility of nanostructure formation was studied by a molecular dynamics method of nonlinear oscillations in atomic oscillator systems of crystal lattices after their low-energy ion irradiation. (authors)

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...

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 ...

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 ...

Low-dimensional geometry from euclidean surfaces to hyperbolic knots

CERN Document Server

Bonahon, Francis

2009-01-01

The study of 3-dimensional spaces brings together elements from several areas of mathematics. The most notable are topology and geometry, but elements of number theory and analysis also make appearances. In the past 30 years, there have been striking developments in the mathematics of 3-dimensional manifolds. This book aims to introduce undergraduate students to some of these important developments. Low-Dimensional Geometry starts at a relatively elementary level, and its early chapters can be used as a brief introduction to hyperbolic geometry. However, the ultimate goal is to describe the very recently completed geometrization program for 3-dimensional manifolds. The journey to reach this goal emphasizes examples and concrete constructions as an introduction to more general statements. This includes the tessellations associated to the process of gluing together the sides of a polygon. Bending some of these tessellations provides a natural introduction to 3-dimensional hyperbolic geometry and to the theory o...

Experimental investigation of cooling perimeter and disturbance length effect on stability of Nb3Sn cable-in-conduit conductors

International Nuclear Information System (INIS)

Armstrong, J.R.

1992-02-01

The stability of three coils, with similar parameters besides having differing strand diameters, was investigated experimentally using inductive heaters to input disturbances. One of the coils stability was also tested by doubling the inductive heated disturbance length to 10 cm. By computationally deriving approximate inductive heater input energy at 12 T, stability curves show fair agreement with zero-dimensional and one-dimensional computer predictions. Quench velocity and limiting currents also show good agreement with earlier work. Also, the stability measured on one of the coils below its limiting current by disturbing a 10 cm length of conductor was much less than the same samples stability using a 5 cm disturbance length. (author)

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

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.

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

Magnetic resonance of low dimensional magnetic solids

Energy Technology Data Exchange (ETDEWEB)

Gatteschi, D.; Ferraro, F.; Sessoli, R. (Florence Univ. (Italy))

1994-06-01

The utility of EPR and NMR in the study of low-dimensional magnetic solids is shown. A short summary of the basis of magnetic resonance in these systems is reported, and the importance of spin-diffusion and magnetic anisotropy evidenced. Some results from experiments on metal-radical chains and clusters are presented. (authors). 37 refs., 7 figs.

Magnetic resonance of low dimensional magnetic solids

International Nuclear Information System (INIS)

Gatteschi, D.; Ferraro, F.; Sessoli, R.

1994-01-01

The utility of EPR and NMR in the study of low-dimensional magnetic solids is shown. A short summary of the basis of magnetic resonance in these systems is reported, and the importance of spin-diffusion and magnetic anisotropy evidenced. Some results from experiments on metal-radical chains and clusters are presented. (authors). 37 refs., 7 figs

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

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.

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

Magnetic levitation by induced eddy currents in non-magnetic conductors and conductivity measurements

Energy Technology Data Exchange (ETDEWEB)

Iniguez, J; Raposo, V; Flores, A G; Zazo, M; Hernandez-Lopez, A [Departamento de Fisica Aplicada, Universidad de Salamanca, E-37071, Salamanca (Spain)

2005-11-01

We report a study on magnetic levitation by induced ac currents in non-magnetic conductors at low frequencies. Our discussion, based on Faraday's induction law, allows us to distinguish the two components of the current responsible for levitation and heating, respectively. The experimental evaluation of the levitation force in a copper ring revealed the accuracy of our analysis, clearly illustrating its asymptotic behaviour versus frequency, and validating it for the qualitative analysis of magnetic levitation and heating in conductors of different shapes such as tubes and discs, composed of collections of conductive loops. The analysis of the results allows precise values of its electrical conductivity to be found. With the help of a simulation technique, this work also reveals the progressive deformation undergone by magnetic induction lines due to magnetic screening when frequency increases.

Synthesis, Properties, and Applications of Low-Dimensional Carbon-Related Nano materials

International Nuclear Information System (INIS)

Mostofizadeh, A.; Li, Y.; Song, B.; Huang, Y.; Mostofizadeh, A.

2011-01-01

In recent years, many theoretical and experimental studies have been carried out to develop one of the most interesting aspects of the science and nano technology which is called carbon-related nano materials. The goal of this paper is to provide a review of some of the most exciting and important developments in the synthesis, properties, and applications of low-dimensional carbon nano materials. Carbon nano materials are formed in various structural features using several different processing methods. The synthesis techniques used to produce specific kinds of low-dimensional carbon nano materials such as zero-dimensional carbon nano materials (including fullerene, carbon-encapsulated metal nanoparticles, nano diamond, and onion-like carbons), one-dimensional carbon nano materials (including carbon nano fibers and carbon nano tubes), and two-dimensional carbon nano materials (including graphene and carbon nano walls) are discussed in this paper. Subsequently, the paper deals with an overview of the properties of the mainly important products as well as some important applications and the future outlooks of these advanced nano materials.

Artificial pinning center technology to enhance vortex pinning in YBCO coated conductors

International Nuclear Information System (INIS)

Matsumoto, Kaname; Mele, Paolo

2010-01-01

Crystalline defects on the nano-scale, which are called artificial pinning centers (APCs), were successfully introduced into high-temperature superconductors (HTS) by nanotechnology, in order to strongly pin the quantized vortices. The critical current densities, J c , of the HTS films were dramatically improved by APCs. It is possible to form APCs in high-quality epitaxial films, keeping the desired dimensionality, volume fraction, spatial distribution and so on. The in-field J c of HTS films at 77 K was improved by one order of magnitude compared with previous values using APCs. This technology can be applied to the coated conductor technology in progress, and a high J c has already been reported. A current outline of the research is described in this review.

Three-Dimensional Organization of Chromosome Territories and the Human Interphase Cell Nucleus

NARCIS (Netherlands)

T.A. Knoch (Tobias); C. Münkel (Christian); J. Langowski (Jörg)

1998-01-01

textabstractTo study the three-dimensional organization of chromosome territories and the human interphase cell nucleus we developed models which could be compared to experiments. Despite the successful linear sequencing of the human genome its 3D-organization is widely unknown. Using Monte

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

Low-Dimensional Feature Representation for Instrument Identification

Science.gov (United States)

Ihara, Mizuki; Maeda, Shin-Ichi; Ikeda, Kazushi; Ishii, Shin

For monophonic music instrument identification, various feature extraction and selection methods have been proposed. One of the issues toward instrument identification is that the same spectrum is not always observed even in the same instrument due to the difference of the recording condition. Therefore, it is important to find non-redundant instrument-specific features that maintain information essential for high-quality instrument identification to apply them to various instrumental music analyses. For such a dimensionality reduction method, the authors propose the utilization of linear projection methods: local Fisher discriminant analysis (LFDA) and LFDA combined with principal component analysis (PCA). After experimentally clarifying that raw power spectra are actually good for instrument classification, the authors reduced the feature dimensionality by LFDA or by PCA followed by LFDA (PCA-LFDA). The reduced features achieved reasonably high identification performance that was comparable or higher than those by the power spectra and those achieved by other existing studies. These results demonstrated that our LFDA and PCA-LFDA can successfully extract low-dimensional instrument features that maintain the characteristic information of the instruments.

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

Shape control synthesis of low-dimensional calcium sulfate

Indian Academy of Sciences (India)

Shape control synthesis of low-dimensional calcium sulfate .... C in mixed solvents of 50 mL ethanol and 30 mL water for different reaction times was characterized by .... Duan X, Huang Y, Cui Y, Wang J and Lieber C M 2001 Nature 409 66.

Resistivity characterisation of Hakone volcano, Central Japan, by three-dimensional magnetotelluric inversion

Science.gov (United States)

Yoshimura, Ryokei; Ogawa, Yasuo; Yukutake, Yohei; Kanda, Wataru; Komori, Shogo; Hase, Hideaki; Goto, Tada-nori; Honda, Ryou; Harada, Masatake; Yamazaki, Tomoya; Kamo, Masato; Kawasaki, Shingo; Higa, Tetsuya; Suzuki, Takeshi; Yasuda, Yojiro; Tani, Masanori; Usui, Yoshiya

2018-04-01

On 29 June 2015, a small phreatic eruption occurred at Hakone volcano, Central Japan, forming several vents in the Owakudani geothermal area on the northern slope of the central cones. Intense earthquake swarm activity and geodetic signals corresponding to the 2015 eruption were also observed within the Hakone caldera. To complement these observations and to characterise the shallow resistivity structure of Hakone caldera, we carried out a three-dimensional inversion of magnetotelluric measurement data acquired at 64 sites across the region. We utilised an unstructured tetrahedral mesh for the inversion code of the edge-based finite element method to account for the steep topography of the region during the inversion process. The main features of the best-fit three-dimensional model are a bell-shaped conductor, the bottom of which shows good agreement with the upper limit of seismicity, beneath the central cones and the Owakudani geothermal area, and several buried bowl-shaped conductive zones beneath the Gora and Kojiri areas. We infer that the main bell-shaped conductor represents a hydrothermally altered zone that acts as a cap or seal to resist the upwelling of volcanic fluids. Enhanced volcanic activity may cause volcanic fluids to pass through the resistive body surrounded by the altered zone and thus promote brittle failure within the resistive body. The overlapping locations of the bowl-shaped conductors, the buried caldera structures and the presence of sodium-chloride-rich hot springs indicate that the conductors represent porous media saturated by high-salinity hot spring waters. The linear clusters of earthquake swarms beneath the Kojiri area may indicate several weak zones that formed due to these structural contrasts.[Figure not available: see fulltext.

Charge-density-wave conductors

International Nuclear Information System (INIS)

Thorne, R.E.

1996-01-01

Low-dimensional metal with moving lattice modulations display a host of unusual properties, including gigantic dielectric constants and the ability to close-quote remember close-quote electrical pulse lengths. copyright 1996 American Institute of Physics

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...

Sensitivity analysis explains quasi-one-dimensional current transport in two-dimensional materials

DEFF Research Database (Denmark)

Boll, Mads; Lotz, Mikkel Rønne; Hansen, Ole

2014-01-01

We demonstrate that the quasi-one-dimensional (1D) current transport, experimentally observed in graphene as measured by a collinear four-point probe in two electrode configurations A and B, can be interpreted using the sensitivity functions of the two electrode configurations (configurations...... A and B represents different pairs of electrodes chosen for current sources and potential measurements). The measured sheet resistance in a four-point probe measurement is averaged over an area determined by the sensitivity function. For a two-dimensional conductor, the sensitivity functions for electrode...... configurations A and B are different. But when the current is forced to flow through a percolation network, e.g., graphene with high density of extended defects, the two sensitivity functions become identical. This is equivalent to a four-point measurement on a line resistor, hence quasi-1D transport...

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...

Fabrication of Stretchable Copper Coated Carbon Nanotube Conductor for Non-Enzymatic Glucose Detection Electrode with Low Detection Limit and Selectivity

Directory of Open Access Journals (Sweden)

Dawei Jiang

2018-03-01

Full Text Available The increasing demand for wearable glucose sensing has stimulated growing interest in stretchable electrodes. The development of the electrode materials having large stretchability, low detection limit, and good selectivity is the key component for constructing high performance wearable glucose sensors. In this work, we presented fabrication of stretchable conductor based on the copper coated carbon nanotube sheath-core fiber, and its application as non-enzymatic electrode for glucose detection with high stretchability, low detection limit, and selectivity. The sheath-core fiber was fabricated by coating copper coated carbon nanotube on a pre-stretched rubber fiber core followed by release of pre-stretch, which had a hierarchically buckled structure. It showed a small resistance change as low as 27% as strain increasing from 0% to 500% strain, and a low resistance of 0.4 Ω·cm−1 at strain of 500%. This electrode showed linear glucose concentration detection in the range between 0.05 mM and 5 mM and good selectivity against sucrose, lactic acid, uric acid, acrylic acid in phosphate buffer saline solution, and showed stable signal in high salt concentration. The limit of detection (LOD was 0.05 mM, for the range of 0.05–5 mM, the sensitivity is 46 mA·M−1. This electrode can withstand large strain of up to 60% with negligible influence on its performance.

Magnetic quantum oscillations of diagonal conductivity in a two-dimensional conductor with a weak square superlattice modulation under conditions of the integer quantum Hall effect

International Nuclear Information System (INIS)

Gvozdikov, V M; Taut, M

2009-01-01

We report on analytical and numerical studies of the magnetic quantum oscillations of the diagonal conductivity σ xx in a two-dimensional conductor with a weak square superlattice modulation under conditions of the integer quantum Hall (IQHE) effect. The quantum Hall effect in such a system differs from the conventional IQHE, in which the finite width of the Landau bands is due to disorder only. The superlattice modulation potential yields a fractal splitting of the Landau levels into Hofstadter minibands. For rational flux through a unit cell, the minibands have a finite width and intrinsic dispersion relations. We consider a regime, now accessible experimentally, in which disorder does not wash out the fractal internal gap structure of the Landau bands completely. We found the following distinctions from the conventional IQHE produced by the superlattice: (i) the peaks in diagonal conductivity are split due to the Hofstadter miniband structure of Landau bands; (ii) the number of split peaks in the bunch, their positions and heights depend irregularly on the magnetic field and the Fermi energy; (iii) the gaps between the split Landau bands (and related quantum Hall plateaus) become narrower with the superlattice modulation than without it.

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....

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

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.

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.

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

Low-Value Service Use in Provider Organizations.

Science.gov (United States)

Schwartz, Aaron L; Zaslavsky, Alan M; Landon, Bruce E; Chernew, Michael E; McWilliams, J Michael

2018-02-01

To assess whether provider organizations exhibit distinct profiles of low-value service provision. 2007-2011 Medicare fee-for-service claims and enrollment data. Use of 31 services that provide minimal clinical benefit was measured for 4,039,733 beneficiaries served by 3,137 provider organizations. Variation across organizations, persistence within organizations over time, and correlations in use of different types of low-value services within organizations were estimated via multilevel modeling, with adjustment for beneficiary sociodemographic and clinical characteristics. Organizations provided 45.6 low-value services per 100 beneficiaries on average, with considerable variation across organizations (90th/10th percentile ratio, 1.78; 95 percent CI, 1.72-1.84), including substantial between-organization variation within hospital referral regions (90th/10th percentile ratio, 1.66; 95 percent CI, 1.60-1.71). Low-value service use within organizations was highly correlated over time (r, 0.98; 95 percent CI, 0.97-0.99) and positively correlated between 13 of 15 pairs of service categories (average r, 0.26; 95 percent CI, 0.24-0.28), with the greatest correlation between low-value imaging and low-value cardiovascular testing and procedures (r, 0.54). Use of low-value services in provider organizations exhibited substantial variation, high persistence, and modest consistency across service types. These findings are consistent with organizations shaping the practice patterns of affiliated physicians. © Health Research and Educational Trust.

Highly conducting one-dimensional solids

CERN Document Server

Evrard, Roger; Doren, Victor

1979-01-01

Although the problem of a metal in one dimension has long been known to solid-state physicists, it was not until the synthesis of real one-dimensional or quasi-one-dimensional systems that this subject began to attract considerable attention. This has been due in part to the search for high­ temperature superconductivity and the possibility of reaching this goal with quasi-one-dimensional substances. A period of intense activity began in 1973 with the report of a measurement of an apparently divergent conduc­ tivity peak in TfF-TCNQ. Since then a great deal has been learned about quasi-one-dimensional conductors. The emphasis now has shifted from trying to find materials of very high conductivity to the many interesting problems of physics and chemistry involved. But many questions remain open and are still under active investigation. This book gives a review of the experimental as well as theoretical progress made in this field over the last years. All the chapters have been written by scientists who have ...

Low-dimensional modeling of a driven cavity flow with two free parameters

DEFF Research Database (Denmark)

Jørgensen, Bo Hoffmann; Sørensen, Jens Nørkær; Brøns, Morten

2003-01-01

. By carrying out such a procedure one obtains a low-dimensional model consisting of a reduced set of Ordinary Differential Equations (ODEs) which models the original equations. A technique called Sequential Proper Orthogonal Decomposition (SPOD) is developed to perform decompositions suitable for low...... parameters to appear in the inhomogeneous boundary conditions without the addition of any constraints. This is necessary because both the driving lid and the rotating rod are controlled simultaneously. Apparently, the results reported for this model are the first to be obtained for a low-dimensional model...

Low dimensional modeling of wall turbulence

Science.gov (United States)

Aubry, Nadine

2015-11-01

In this talk we will review the original low dimensional dynamical model of the wall region of a turbulent boundary layer [Aubry, Holmes, Lumley and Stone, Journal of Fluid Dynamics 192, 1988] and discuss its impact on the field of fluid dynamics. We will also invite a few researchers who would like to make brief comments on the influence Lumley had on their research paths. In collaboration with Philip Holmes, Program in Applied and Computational Mathematics and Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ.

Dynamic model of organic pollutant degradation in three dimensional packed bed electrode reactor.

Science.gov (United States)

Pang, Tianting; Wang, Yan; Yang, Hui; Wang, Tianlei; Cai, Wangfeng

2018-04-21

A dynamic model of semi-batch three-dimensional electrode reactor was established based on the limiting current density, Faraday's law, mass balance and a series of assumptions. Semi-batch experiments of phenol degradation were carried out in a three-dimensional electrode reactor packed with activated carbon under different conditions to verify the model. The factors such as the current density, the electrolyte concentration, the initial pH value, the flow rate of organic and the initial organic concentration were examined to know about the pollutant degradation in the three-dimensional electrode reactor. The various concentrations and logarithm of concentration of phenol with time were compared with the dynamic model. It was shown that the calculated data were in good agreement with experimental data in most cases. Copyright © 2018 Elsevier Ltd. All rights reserved.

Development of cost-effective Nb3Sn conductors for the next generation hadron colliders

International Nuclear Information System (INIS)

Scanlan, R.M.; Dietderich, D.R.; Zeitlin, B.A.

2001-01-01

Significant progress has been made in demonstrating that reliable, efficient high field dipole magnets can be made with Nb 3 Sn superconductors. A key factor in determining whether these magnets will be a cost-effective solution for the next generation hadron collider is the conductor cost. Consequently, DOE initiated a conductor development program to demonstrate that Nb 3 Sn can be improved to reach a cost/performance value of $1.50/kA-m at 12T, 4.2K. The first phase of this program was initiated in Jan 2000, with the goal of improving the key properties of interest for accelerator dipole magnets--high critical current density and low magnetization. New world record critical current densities have been reported recently, and it appears that significant potential exists for further improvement. Although new techniques for compensating for magnetization effects have reduced the requirements somewhat, techniques for lowering the effective filament size while maintaining these high Jc values are a program priority. The next phase of this program is focused on reducing the conductor cost through substitution of lower cost raw materials and through process improvements. The cost drivers for materials and fabrication have been identified, and projects are being initiated to demonstrate cost reductions

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 (...

A low dimensional dynamical system for the wall layer

Science.gov (United States)

Aubry, N.; Keefe, L. R.

1987-01-01

Low dimensional dynamical systems which model a fully developed turbulent wall layer were derived.The model is based on the optimally fast convergent proper orthogonal decomposition, or Karhunen-Loeve expansion. This decomposition provides a set of eigenfunctions which are derived from the autocorrelation tensor at zero time lag. Via Galerkin projection, low dimensional sets of ordinary differential equations in time, for the coefficients of the expansion, were derived from the Navier-Stokes equations. The energy loss to the unresolved modes was modeled by an eddy viscosity representation, analogous to Heisenberg's spectral model. A set of eigenfunctions and eigenvalues were obtained from direct numerical simulation of a plane channel at a Reynolds number of 6600, based on the mean centerline velocity and the channel width flow and compared with previous work done by Herzog. Using the new eigenvalues and eigenfunctions, a new ten dimensional set of ordinary differential equations were derived using five non-zero cross-stream Fourier modes with a periodic length of 377 wall units. The dynamical system was integrated for a range of the eddy viscosity prameter alpha. This work is encouraging.

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.

The effect of low temperature cryocoolers on the development of low temperature superconducting magnets

International Nuclear Information System (INIS)

Green, Michael A.

2000-01-01

The commercial development of reliable 4 K cryocoolers improves the future prospects for magnets made from low temperature superconductors (LTS). The hope of the developers of high temperature superconductors (HTS) has been to replace liquid helium cooled LTS magnets with HTS magnets that operate at or near liquid nitrogen temperature. There has been limited success in this endeavor, but continued problems with HTS conductors have greatly slowed progress toward this goal. The development of cryocoolers that reliably operate below 4 K will allow magnets made from LTS conductor to remain very competitive for many years to come. A key enabling technology for the use of low temperature cryocoolers on LTS magnets has been the development of HTS leads. This report describes the characteristics of LTS magnets that can be successfully melded to low-temperature cryocoolers. This report will also show when it is not appropriate to consider the use of low-temperature cryocoolers to cool magnets made with LTS conductor. A couple of specific examples of LTS magnets where cryocoolers can be used are given

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.

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.

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

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.

C4N3H monolayer: A two-dimensional organic Dirac material with high Fermi velocity

Science.gov (United States)

Pan, Hongzhe; Zhang, Hongyu; Sun, Yuanyuan; Li, Jianfu; Du, Youwei; Tang, Nujiang

2017-11-01

Searching for two-dimensional (2D) organic Dirac materials, which have more adaptable practical applications compared with inorganic ones, is of great significance and has been ongoing. However, only two such materials with low Fermi velocity have been discovered so far. Herein, we report the design of an organic monolayer with C4N3H stoichiometry that possesses fascinating structure and good stability in its free-standing state. More importantly, we demonstrate that this monolayer is a semimetal with anisotropic Dirac cones and very high Fermi velocity. This Fermi velocity is roughly one order of magnitude larger than the largest velocity ever reported in 2D organic Dirac materials, and it is comparable to that in graphene. The Dirac states in this monolayer arise from the extended π -electron conjugation system formed by the overlapping 2 pz orbitals of carbon and nitrogen atoms. Our finding paves the way to a search for more 2D organic Dirac materials with high Fermi velocity.

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...

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

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

Microscopic theory of the superconducting gap in the quasi-one-dimensional organic conductor (TMTSF) 2ClO4 : Model derivation and two-particle self-consistent analysis

Science.gov (United States)

Aizawa, Hirohito; Kuroki, Kazuhiko

2018-03-01

We present a first-principles band calculation for the quasi-one-dimensional (Q1D) organic superconductor (TMTSF) 2ClO4 . An effective tight-binding model with the TMTSF molecule to be regarded as the site is derived from a calculation based on maximally localized Wannier orbitals. We apply a two-particle self-consistent (TPSC) analysis by using a four-site Hubbard model, which is composed of the tight-binding model and an onsite (intramolecular) repulsive interaction, which serves as a variable parameter. We assume that the pairing mechanism is mediated by the spin fluctuation, and the sign of the superconducting gap changes between the inner and outer Fermi surfaces, which correspond to a d -wave gap function in a simplified Q1D model. With the parameters we adopt, the critical temperature for superconductivity estimated by the TPSC approach is approximately 1 K, which is consistent with experiment.

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

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.

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

Thermal transport in a two-dimensional Z2 spin liquid

Science.gov (United States)

Metavitsiadis, Alexandros; Pidatella, Angelo; Brenig, Wolfram

2017-11-01

We study the dynamical thermal conductivity of the two-dimensional Kitaev spin model on the honeycomb lattice. We find a strongly temperature dependent low-frequency spectral intensity as a direct consequence of fractionalization of spins into mobile Majorana matter and a static Z2 gauge field. The latter acts as an emergent thermally activated disorder, leading to the appearance of a pseudogap which closes in the thermodynamic limit, indicating a dissipative heat conductor. Our analysis is based on complementary calculations of the current correlation function, comprising exact diagonalization by means of a complete summation over all gauge sectors, as well as a phenomenological mean-field treatment of thermal gauge fluctuations, valid at intermediate and high temperatures. The results will also be contrasted against the conductivity discarding gauge fluctuations.

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.

Three-dimensional numerical modelling of a magnetically deflected dc transferred arc in argon

International Nuclear Information System (INIS)

Blais, A; Proulx, P; Boulos, M I

2003-01-01

The aim of this work is to develop a numerical model for the deflection of dc transferred arcs using an external magnetic field as a first step into the modelling of industrial arc furnaces. The arc is deflected by the use of a conductor aligned parallel to the arc axis through which flows an electric current. The model is validated by comparing the results of axisymmetric calculations to modelling results from the scientific literature. The present model is found to be a good representation of the electric dc arc as differences with the literature are easily explained by model parameters such as the critical boundary conditions at the electrodes. Transferred arc cases exhibit the expected behaviour as the temperature T, the velocity v-vector and the electrical potential drop Δφ all increase with the arc current I and the argon flow rate Q. Three-dimensional geometry is implemented, enabling one to numerically deflect the arc. For the deflected arc cases, the deflection increases with the arc current I and conductor current I conductor and decreases with the flow rate Q and x 0 , the arc-conductor distance. These deflection behaviours are explained using physical arguments

Low-resistance gateless high electron mobility transistors using three-dimensional inverted pyramidal AlGaN/GaN surfaces

International Nuclear Information System (INIS)

So, Hongyun; Senesky, Debbie G.

2016-01-01

In this letter, three-dimensional gateless AlGaN/GaN high electron mobility transistors (HEMTs) were demonstrated with 54% reduction in electrical resistance and 73% increase in surface area compared with conventional gateless HEMTs on planar substrates. Inverted pyramidal AlGaN/GaN surfaces were microfabricated using potassium hydroxide etched silicon with exposed (111) surfaces and metal-organic chemical vapor deposition of coherent AlGaN/GaN thin films. In addition, electrical characterization of the devices showed that a combination of series and parallel connections of the highly conductive two-dimensional electron gas along the pyramidal geometry resulted in a significant reduction in electrical resistance at both room and high temperatures (up to 300 °C). This three-dimensional HEMT architecture can be leveraged to realize low-power and reliable power electronics, as well as harsh environment sensors with increased surface area

Low-resistance gateless high electron mobility transistors using three-dimensional inverted pyramidal AlGaN/GaN surfaces

Energy Technology Data Exchange (ETDEWEB)

So, Hongyun, E-mail: hyso@stanford.edu [Department of Aeronautics and Astronautics, Stanford University, Stanford, California 94305 (United States); Senesky, Debbie G. [Department of Aeronautics and Astronautics, Stanford University, Stanford, California 94305 (United States); Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

2016-01-04

In this letter, three-dimensional gateless AlGaN/GaN high electron mobility transistors (HEMTs) were demonstrated with 54% reduction in electrical resistance and 73% increase in surface area compared with conventional gateless HEMTs on planar substrates. Inverted pyramidal AlGaN/GaN surfaces were microfabricated using potassium hydroxide etched silicon with exposed (111) surfaces and metal-organic chemical vapor deposition of coherent AlGaN/GaN thin films. In addition, electrical characterization of the devices showed that a combination of series and parallel connections of the highly conductive two-dimensional electron gas along the pyramidal geometry resulted in a significant reduction in electrical resistance at both room and high temperatures (up to 300 °C). This three-dimensional HEMT architecture can be leveraged to realize low-power and reliable power electronics, as well as harsh environment sensors with increased surface area.

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...

2012 Aspen Winter Conference New Paradigms for Low-Dimensional Electronic Materials, February 5-10, 2012

Energy Technology Data Exchange (ETDEWEB)

Moore, Joel; Rabe, Karin; Nayak, Chetan; Troyer, Matthias

2012-05-01

Aspen Center for Physics Project Summary DOE Budget Period: 10/1/2011 to 9/30/2012 Contract # DE-SC0007479 New Paradigms for Low-Dimensional Electronic Materials The 2012 Aspen Winter Conference on Condensed Matter Physics was held at the Aspen Center for Physics from February 5 to 10, 2012. Seventy-four participants from seven countries, and several universities and national labs attended the workshop titled, New Paradigms for Low-Dimensional Electronic Materials. There were 34 formal talks, and a number of informal discussions held during the week. Talks covered a variety of topics related to DOE BES priorities, including, for example, advanced photon techniques (Hasan, Abbamonte, Orenstein, Shen, Ghosh) and predictive theoretical modeling of materials properties (Rappe, Pickett, Balents, Zhang, Vanderbilt); the full conference schedule is provided with this report. The week's events included a public lecture (Quantum Matters given by Chetan Nayak from Microsoft Research) and attended by 234 members of the public, and a physics caf© geared for high schoolers that is a discussion with physicists conducted by Kathryn Moler (Stanford University) and Andrew M. Rappe (University of Pennsylvania) and attended by 67 locals and visitors. While there were no published proceedings, some of the talks are posted online and can be Googled. The workshop was organized by Joel Moore (University of California Berkeley), Chetan Nayak (Microsoft Research), Karin Rabe (Rutgers University), and Matthias Troyer (ETH Zurich). Two organizers who did not attend the conference were Gabriel Aeppli (University College London & London Centre for Nanotechnology) and Andrea Cavalleri (Oxford University & Max Planck Hamburg).

Statistical mechanics of low-dimensional Ginzburg-Landau fields. Some new results

International Nuclear Information System (INIS)

Barsan, V.

1987-08-01

The Ginzburg-Landau theory for low-dimensional systems is approached using the transfer matrix method. Analitical formulae for the thermodynamical quantities of interest are obtained in the one-dimensional case. An exact expression for the free energy of of a planar array of linear chains is deduced. A good agrement with numerical and experimental data is found.(authors)

Low Dimensionality Effects in Complex Magnetic Oxides

Science.gov (United States)

Kelley, Paula J. Lampen

Complex magnetic oxides represent a unique intersection of immense technological importance and fascinating physical phenomena originating from interwoven structural, electronic and magnetic degrees of freedom. The resulting energetically close competing orders can be controllably selected through external fields. Competing interactions and disorder represent an additional opportunity to systematically manipulate the properties of pure magnetic systems, leading to frustration, glassiness, and other novel phenomena while finite sample dimension plays a similar role in systems with long-range cooperative effects or large correlation lengths. A rigorous understanding of these effects in strongly correlated oxides is key to manipulating their functionality and device performance, but remains a challenging task. In this dissertation, we examine a number of problems related to intrinsic and extrinsic low dimensionality, disorder, and competing interactions in magnetic oxides by applying a unique combination of standard magnetometry techniques and unconventional magnetocaloric effect and transverse susceptibility measurements. The influence of dimensionality and disorder on the nature and critical properties of phase transitions in manganites is illustrated in La0.7 Ca0.3MnO3, in which both size reduction to the nanoscale and chemically-controlled quenched disorder are observed to induce a progressive weakening of the first-order nature of the transition, despite acting through the distinct mechanisms of surface effects and site dilution. In the second-order material La0.8Ca0.2MnO3, a strong magnetic field is found to drive the system toward its tricritical point as competition between exchange interactions in the inhomogeneous ground state is suppressed. In the presence of large phase separation stabilized by chemical disorder and long-range strain, dimensionality has a profound effect. With the systematic reduction of particle size in microscale-phase-separated (La, Pr

Epitaxial solution deposition of YBa2Cu3O7-6 coated conductors.

Energy Technology Data Exchange (ETDEWEB)

Overmyer, Donald L.; Clem, Paul Gilbert; Siegal, Michael P.; Holesinger, Terry A. (Los Alamos National Laboratory, Los Alamos, NM); Voigt, James A.; Richardson, Jacob J.; Dawley, Jeffrey Todd

2004-11-01

A variety of solution deposition routes have been reported for processing complex perovskite-based materials such as ferroelectric oxides and conductive electrode oxides, due to ease of incorporating multiple elements, control of chemical stoichiometry, and feasibility for large area deposition. Here, we report an extension of these methods toward long length, epitaxial film solution deposition routes to enable biaxially oriented YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO)-coated conductors for superconducting transmission wires. Recent results are presented detailing an all-solution deposition approach to YBCO-coated conductors with critical current densities J{sub c} (77 K) > 1 MA/cm{sup 2} on rolling-assisted, biaxially textured, (200)-oriented Ni-W alloy tapes. Solution-deposition methods such as this approach and those of other research groups appear to have promise to compete with vapor phase methods for superconductor electrical properties, with potential advantages for large area deposition and low cost/kA {center_dot} m of wire.

Two-dimensional concentrated-stress low-frequency piezoelectric vibration energy harvesters

Energy Technology Data Exchange (ETDEWEB)

Sharpes, Nathan [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States); Abdelkefi, Abdessattar [Department of Mechanical and Aerospace Engineering, New Mexico State University, Las Cruces, New Mexico 88003 (United States); Priya, Shashank [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States); Bio-Inspired Materials and Devices Laboratory (BMDL), Virginia Tech, Blacksburg, Virginia 24061 (United States)

2015-08-31

Vibration-based energy harvesters using piezoelectric materials have long made use of the cantilever beam structure. Surmounting the deficiencies in one-dimensional cantilever-based energy harvesters has been a major focus in the literature. In this work, we demonstrate a strategy of using two-dimensional beam shapes to harvest energy from low frequency excitations. A characteristic Zigzag-shaped beam is created to compare against the two proposed two-dimensional beam shapes, all of which occupy a 25.4 × 25.4 mm{sup 2} area. In addition to maintaining the low-resonance bending frequency, the proposed beam shapes are designed with the goal of realizing a concentrated stress structure, whereby stress in the beam is concentrated in a single area where a piezoelectric layer may be placed, rather than being distributed throughout the beam. It is shown analytically, numerically, and experimentally that one of the proposed harvesters is able to provide significant increase in power production, when the base acceleration is set equal to 0.1 g, with only a minimal change in the resonant frequency compared to the current state-of-the-art Zigzag shape. This is accomplished by eliminating torsional effects, producing a more pure bending motion that is necessary for high electromechanical coupling. In addition, the proposed harvesters have a large effective beam tip whereby large tip mass may be placed while retaining a low-profile, resulting in a low volume harvester and subsequently large power density.

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.

Supercapacitors based on two dimensional VO2 nanosheet electrodes in organic gel electrolyte

KAUST Repository

Rakhi, R.B.

2016-10-16

VO2 is a low band-gap semiconductor with relatively high conductivity among transition metal oxides, which makes it an interesting material for supercapacitor electrode applications. The performance of VO2 as supercapacitor electrode in organic electrolytes has never been reported before. Herein, two-dimensional nanosheets of VO2 are prepared by the simultaneous solution reduction and exfoliation from bulk V2O5 powder by hydrothermal method. A specific capacitance of 405 Fg−1 is achieved for VO2 based supercapacitor in an organic electrolyte, in three electrode configuration. The symmetric capacitor based on VO2 nanosheet electrodes and the liquid organic electrolyte exhibits an energy density of 46 Wh kg−1 at a power density of 1.4 kW kg−1 at a constant current density of 1 Ag−1. Furthermore, flexible solid-state supercapacitors are fabricated using same electrode material and Alumina-silica based gel electrolyte. The solid-state device delivers a specific capacitance of 145 Fg−1 and a device capacitance of 36 Fg−1 at a discharge current density of 1 Ag−1. Series combination of three solid state capacitors is capable of lighting up a red LED for more than 1 minute.

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

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

Lack of evidence for low-dimensional chaos in heart rate variability

DEFF Research Database (Denmark)

Kanters, J K; Holstein-Rathlou, N H; Agner, E

1994-01-01

INTRODUCTION: The term chaos is used to describe erratic or apparently random time-dependent behavior in deterministic systems. It has been suggested that the variability observed in the normal heart rate may be due to chaos, but this question has not been settled. METHODS AND RESULTS: Heart rate...... in the experimental data, but the prediction error as a function of the prediction length increased at a slower rate than characteristic of a low-dimensional chaotic system. CONCLUSION: There is no evidence for low-dimensional chaos in the time series of RR intervals from healthy human subjects. However, nonlinear...

On interaction of P-waves with one-dimensional photonic crystal consisting of weak conducting matter and transparent dielectric layers

Science.gov (United States)

Yushkanov, A. A.; Zverev, N. V.

2018-03-01

An influence of quantum and spatial dispersion properties of the non-degenerate electron plasma on the interaction of electromagnetic P-waves with one-dimensional photonic crystal consisting of conductor with low carrier electron density and transparent dielectric matter, is studied numerically. It is shown that at the frequencies of order of the plasma frequency and at small widths of the conducting and dielectric layers of the photonic crystal, optical coefficients in the quantum non-degenerate plasma approach differ from the coefficients in the classical electron gas approach. And also, at these frequencies one observes a temperature dependence of the optical coefficients.

Copper and CuNi alloys substrates for HTS coated conductor applications protected from oxidation

Energy Technology Data Exchange (ETDEWEB)

Segarra, M; Diaz, J; Xuriguera, H; Chimenos, J M; Espiell, F [Dept. of Chemical Engineering and Metallurgy, Univ. of Barcelona, Barcelona (Spain); Miralles, L [Lab. d' Investigacio en Formacions Geologiques. Dept. of Petrology, Geochemistry and Geological Prospecting, Univ. of Barcelona, Barcelona (Spain); Pinol, S [Inst. de Ciencia de Materials de Barcelona, Bellaterra (Spain)

2003-07-01

Copper is an interesting substrate for HTS coated conductors for its low cost compared to other metallic substrates, and for its low resistivity. Nevertheless, mechanical properties and resistance to oxidation should be improved in order to use it as substrate for YBCO deposition by non-vacuum techniques. Therefore, different cube textured CuNi tapes were prepared by RABIT as possible substrates for deposition of high critical current density YBCO films. Under the optimised conditions of deformation and annealing, all the studied CuNi alloys (2%, 5%, and 10% Ni) presented (100) left angle 001 right angle cube texture which is compatible for YBCO deposition. Textured CuNi alloys present higher tensile strength than pure copper. Oxidation resistance of CuNi tapes under different oxygen atmospheres was also studied by thermogravimetric analysis and compared to pure copper tapes. Although the presence of nickel improves mechanical properties of annealed copper, it does not improve its oxidation resistance. However, when a chromium buffer layer is electrodeposited on the tape, oxygen diffusion is slowed down. Chromium is, therefore, useful for protecting copper and CuNi alloys from oxidation although its recrystallisation texture, (110), is not suitable for coated conductors. (orig.)

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...

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

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.

submitter Development of Joint Terminals for a New Six-Around-One ReBCO-CORC Cable-in-Conduit Conductor Rated 45 kA at 10T/4K

CERN Document Server

Mulder, Tim; Mentink, Matthias; Dhalle, Marc; Ten Kate, Herman

2016-01-01

The European Organization for Nuclear Research (CERN) is developing a six-around-one conductor on round core (CORC)-strand-based cable-in-conduit conductor (CICC) for use in detector and other large magnet systems. The CICC comprises six ReBCO-CORC strands helically wound around a central tube or rod and inserted in a square aluminum jacket. A major design challenge is finding a simple yet low-resistive method of injecting current homogeneously into the CORC strands of the CICC. In the production of joints for single-CORC cables, we are currently pursuing a method in which the different ReBCO layers at both ends of the CORC cable are trimmed into a staircase-like geometry. A similar trimming method is developed for joint terminals for the ReBCO-CORC-based CICC. A demonstration joint terminal is made to test the various steps of the trimming and manufacturing process before fabricating a joint terminal with real CORC strands. This paper presents an overview of CIC-joint terminal design, simulation results, and...

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)

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.

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

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.

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.

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)

All-chemical YBa2Cu3O7 coated conductors on IBAD-YSZ stainless steel substrates

International Nuclear Information System (INIS)

Pomar, A; Cavallaro, A; Coll, M; Gazquez, J; Palau, A; Sandiumenge, F; Puig, T; Obradors, X; Freyhardt, H C

2006-01-01

We report on the fabrication of all-chemical YBa 2 Cu 3 O 7 coated conductors on IBAD-YSZ (IBAD stands for ion beam assisted deposition; YSZ is yttrium stabilized zirconia) stainless steel substrates. YBCO films were grown by the trifluoroacetates route on top of CeO 2 buffer layers made by metal-organic decomposition. The achievement of atomically flat CeO 2 surfaces is found to be a key factor for obtaining clean interfaces with YBCO and high performance. Coated conductors with percolative critical currents of J c GB (65 K) = 1.8 MA cm -2 were achieved. The determination of the intra-grain critical current J c G from inductive measurements suggests that the limiting factor for J c GB is the YBCO in-plane texture, which is already of higher quality than that of the IBAD-YSZ cap layer. (rapid communication)

High pressure, high current, low inductance, high reliability sealed terminals

Science.gov (United States)

Hsu, John S [Oak Ridge, TN; McKeever, John W [Oak Ridge, TN

2010-03-23

The invention is a terminal assembly having a casing with at least one delivery tapered-cone conductor and at least one return tapered-cone conductor routed there-through. The delivery and return tapered-cone conductors are electrically isolated from each other and positioned in the annuluses of ordered concentric cones at an off-normal angle. The tapered cone conductor service can be AC phase conductors and DC link conductors. The center core has at least one service conduit of gate signal leads, diagnostic signal wires, and refrigerant tubing routed there-through. A seal material is in direct contact with the casing inner surface, the tapered-cone conductors, and the service conduits thereby hermetically filling the interstitial space in the casing interior core and center core. The assembly provides simultaneous high-current, high-pressure, low-inductance, and high-reliability service.

Synthesis and structure of novel lithium-ion conductor Li{sub 7}Ge{sub 3}PS{sub 12}

Energy Technology Data Exchange (ETDEWEB)

Inoue, Yuki [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8502 (Japan); Suzuki, Kota [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8502 (Japan); Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8502 (Japan); Matsui, Naoki [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8502 (Japan); Hirayama, Masaaki [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8502 (Japan); Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8502 (Japan); Kanno, Ryoji, E-mail: kanno@echem.titech.ac.jp [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8502 (Japan); Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8502 (Japan)

2017-02-15

The novel lithium-ion conductor Li{sub 7}Ge{sub 3}PS{sub 12} was synthesized by slow cooling from the ternary Li{sub 2}S–GeS{sub 2}–P{sub 2}S{sub 5} system, and was shown to exhibit a cubic argyrodite-type structure. The phase composition was determined by varying the ratio of starting materials; the observed monophasic properties were close to those for the Li{sub 7}Ge{sub 3}PS{sub 12} composition. The lattice parameter (a =9.80192(3) Å) of Li{sub 7}Ge{sub 3}PS{sub 12} was slightly smaller than that of Li{sub 7}PS{sub 6} (a =9.993 Å), indicating that substitution of a Li cation by the smaller Ge cation contracted the cubic lattice. In addition, the novel structure consisted of a framework composed of four isolated (Ge/P)S{sub 4} tetrahedra. Li{sup +} ions occupied tetrahedral sites within the framework, forming a three-dimensional conduction pathway. Finally, Li{sub 7}Ge{sub 3}PS{sub 12} exhibited a high ionic conductivity of 1.1×10{sup −4} S cm{sup −1} at 25 °C and an activation energy of 25 kJ mol{sup −1}. - Graphical abstract: A novel Li{sub 7}Ge{sub 3}PS{sub 12} solid lithium ion conductor, with cubic argyrodite strucuture, shows high ion conductivity of 1.1×10{sup –4} S cm{sup –1} with an activation energy of 25 kJ mol{sup –1}. The argyrodite structure consists of (Ge/P)S{sub 4} tetrahedra units along with partial occupation of lithium and germanium at 48 h site. - Highlights: • A novel lithium-ion conductor Li{sub 7}Ge{sub 3}PS{sub 12} was detected. • This was achieved through slow cooling of the ternary Li{sub 2}S–GeS{sub 2}–P{sub 2}S{sub 5} system. • This novel conductor revealed a cubic argyrodite-type structure. • Li{sub 7}Ge{sub 3}PS{sub 12} exhibited a high ionic conductivity of 1.1×10{sup −4} S cm{sup −1} at 25 °C. • These properties will aid in the design of superior lithium-ion conductors.

General Strategy for Rapid Production of Low-Dimensional All-Inorganic CsPbBr3 Perovskite Nanocrystals with Controlled Dimensionalities and Sizes.

Science.gov (United States)

Liu, Wenna; Zheng, Jinju; Cao, Sheng; Wang, Lin; Gao, Fengmei; Chou, Kuo-Chih; Hou, Xinmei; Yang, Weiyou

2018-02-05

Currently, all-inorganic CsPbX 3 (X = Br, I, Cl) perovskite nanocrystals (NCs) are shining stars with exciting potential applications in optoelectronic devices such as solar cells, light-emitting diodes, lasers, and photodetectors, due to their superior performance in comparison to their organic-inorganic hybrid counterparts. In the present work, we report a general strategy based on a microwave technique for the rapid production of low-dimensional all-inorganic CsPbBr 3 perovskite NCs with tunable morphologies within minutes. The effect of the key parameters such as the introduced ligands, solvents, and PbBr 2 precursors and microwave powers as well as the irradiation times on the production of perovskite NCs was systematically investigated, which allowed their growth with tunable dimensionalities and sizes. As a proof of concept, the ratio of OA to OAm as well as the concentration of PbBr 2 precursor played important roles in triggering the anisotropic growth of the perovskite NCs, favoring their growth into 1D/2D single-crystalline nanostructures. Meanwhile, their sizes could be tailored by controlling the microwave powers and irradiation times. The mechanism for the tunable growth of perovskite NCs is discussed.

Effective method for construction of low-dimensional models for heat transfer process

Energy Technology Data Exchange (ETDEWEB)

Blinov, D.G.; Prokopov, V.G.; Sherenkovskii, Y.V.; Fialko, N.M.; Yurchuk, V.L. [National Academy of Sciences of Ukraine, Kiev (Ukraine). Inst. of Engineering Thermophysics

2004-12-01

A low-dimensional model based on the method of proper orthogonal decomposition (POD) and the method of polyargumental systems (MPS) for thermal conductivity problems with strongly localized source of heat has been presented. The key aspect of these methods is that they enable to avoid weak points of other projection methods, which consists in a priori choice of basis functions. It enables us to use the MPS method and the POD method as convenient means to construct low-dimensional models of heat and mass transfer problems. (Author)

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.

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.

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

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 ...

Correlation functions of one-dimensional bosons at low temperature

Energy Technology Data Exchange (ETDEWEB)

Kozlowski, K.K. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Maillet, J.M. [CNRS, ENS Lyon (France). Lab. de Physique; Slavnov, N.A. [Steklov Mathematical Institute, Moscow (Russian Federation)

2010-12-15

We consider the low-temperature limit of the long-distance asymptotic behavior of the finite temperature density-density correlation function in the one-dimensional Bose gas derived recently in the algebraic Bethe Ansatz framework. Our results confirm the predictions based on the Luttinger liquid and conformal field theory approaches. We also demonstrate that the amplitudes arising in this asymptotic expansion at low-temperature coincide with the amplitudes associated with the so-called critical form factors. (orig.)

Magnetometry of low-dimensional electron and hole systems

Energy Technology Data Exchange (ETDEWEB)

Usher, A [School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom); Elliott, M [School of Physics and Astronomy, Cardiff University, Queens Buildings, Cardiff CF24 3AA (United Kingdom)], E-mail: a.usher@exeter.ac.uk, E-mail: elliottm@cf.ac.uk

2009-03-11

The high-magnetic-field, low-temperature magnetic properties of low-dimensional electron and hole systems reveal a wealth of fundamental information. Quantum oscillations of the thermodynamic equilibrium magnetization yield the total density of states, a central quantity in understanding the quantum Hall effect in 2D systems. The magnetization arising from non-equilibrium circulating currents reveals details, not accessible with traditional measurements, of the vanishingly small longitudinal resistance in the quantum Hall regime. We review how the technique of magnetometry has been applied to these systems, the most important discoveries that have been made, and their theoretical significance. (topical review)

Band Gap Tuning and Defect Tolerance of Atomically Thin Two-Dimensional Organic-Inorganic Halide Perovskites.

Science.gov (United States)

Pandey, Mohnish; Jacobsen, Karsten W; Thygesen, Kristian S

2016-11-03

Organic-inorganic halide perovskites have proven highly successful for photovoltaics but suffer from low stability, which deteriorates their performance over time. Recent experiments have demonstrated that low dimensional phases of the hybrid perovskites may exhibit improved stability. Here we report first-principles calculations for isolated monolayers of the organometallic halide perovskites (C 4 H 9 NH 3 ) 2 MX 2 Y 2 , where M = Pb, Ge, Sn and X,Y = Cl, Br, I. The band gaps computed using the GLLB-SC functional are found to be in excellent agreement with experimental photoluminescence data for the already synthesized perovskites. Finally, we study the effect of different defects on the band structure. We find that the most common defects only introduce shallow or no states in the band gap, indicating that these atomically thin 2D perovskites are likely to be defect tolerant.

Diffusion pathway of mobile ions and crystal structure of ionic and mixed conductors. A brief review

International Nuclear Information System (INIS)

Yashima, Masatomo

2009-01-01

A brief review on the field of Solid State Ionics, including the diffusion pathway of mobile ions, crystal structure and materials, is presented. In the fluorite-structured ionic conductors such as ceria solid solution Ce 0.93 Y 0.07 O 1.96 , bismuth oxide solid solution δ-Bi 1.4 Yb 0.6 O 3 and copper iodide CuI, a similar curved diffusion pathway along the directions is observed. In the ionic and mixed conductors with the cubic ABO 3 perovskite-type structure such as lanthanum gallate and lanthanum cobaltite solid solutions, the mobile ions diffuse along a curved line keeping the interatomic distance between the B cation and O 2- anion to some degree. The structure and diffusion path of double-perovskite-type La 0.64 Ti 0.92 Nb 0.08 O 2.99 , K 2 NiF 4 -type (Pr 0.9 La 0.1 ) 2 (Ni 0.74 Cu 0.21 Ga 0.05 )O 4+δ , and apatite-type La 9.69 (Si 5.70 Mg 0.30 )O 26.24 are described. The diffusion paths of Li + ions in La 0.62 Li 0.16 TiO 3 and Li 0.6 FePO 4 are two- and one-dimensional, respectively. (author)

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.

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

Gain Enhanced On-Chip Folded Dipole Antenna Utilizing Artificial Magnetic Conductor at 94 GHz

KAUST Repository

Nafe, Mahmoud; Syed, Ahad; Shamim, Atif

2017-01-01

On-chip antennas suffer from low gain values and distorted radiation patterns due to lossy and high permittivity Si substrate. An ideal solution would be to isolate the lossy Si substrate from the antenna through a Perfect Electric Conductor (PEC) ground plane, however the typical CMOS stack up which has multiple metal layers embedded in a thin oxide layer does not permit this. In this work, an Artificial Magnetic Conductor (AMC) reflecting surface has been utilized to isolate the Si substrate from the antenna. Contrary to the previous reports, the AMC structure is completely embedded in the thin oxide layer with the ground plane above the Si substrate. In this approach, the AMC surface acts for the first time as both a reflector and a silicon shield. As a result the antenna radiation pattern is not distorted and its gain is improved by 8 dB. The fabricated prototype demonstrates good impedance and radiation characteristics.

Gain Enhanced On-Chip Folded Dipole Antenna Utilizing Artificial Magnetic Conductor at 94 GHz

KAUST Repository

Nafe, Mahmoud

2017-09-05

On-chip antennas suffer from low gain values and distorted radiation patterns due to lossy and high permittivity Si substrate. An ideal solution would be to isolate the lossy Si substrate from the antenna through a Perfect Electric Conductor (PEC) ground plane, however the typical CMOS stack up which has multiple metal layers embedded in a thin oxide layer does not permit this. In this work, an Artificial Magnetic Conductor (AMC) reflecting surface has been utilized to isolate the Si substrate from the antenna. Contrary to the previous reports, the AMC structure is completely embedded in the thin oxide layer with the ground plane above the Si substrate. In this approach, the AMC surface acts for the first time as both a reflector and a silicon shield. As a result the antenna radiation pattern is not distorted and its gain is improved by 8 dB. The fabricated prototype demonstrates good impedance and radiation characteristics.

Dimensional and correlation effects of charged excitons in low-dimensional semiconductors

Energy Technology Data Exchange (ETDEWEB)

Roennow, Troels F; Pedersen, Thomas G [Department of Physics and Nanotechnology, Aalborg University, Skjernvej 4A, 9220 Aalborg Oest (Denmark); Cornean, Horia D, E-mail: tfr@nanophysics.d [Department of Mathematical Sciences, Aalborg University, Frederik Bajers Vej 7G, 9220 Aalborg (Denmark)

2010-11-26

In this paper, we investigate the existence of bound trion states in fractional dimensional nanostructures, in terms of variational calculus. We start with trial states, then we refine the result with the help of the Hartree-Fock approximation and finally we use a partial basis expansion. We show that Hartree-Fock significantly underestimates the trion binding energy and that the correlation energy is comparable with the trion binding energy. Furthermore we calculate the binding energies of positive and negative trions restricted to a large subspace of functions, which we expect to span the low-lying eigenstates of the full Hamiltonian. We find that the difference between the positive and negative trion binding energies varies very little for the electron-hole mass fractions m{sub e}/m{sub h} = {sigma} in [0.8; 1.0] and that the difference between the positive and negative trion energies grows as the dimension decreases. Finally, we compare a cylindrical effective-mass model of a typical carbon nanotube, with a fractional dimensional model with D = 1.71. We find very good agreement between the trion binding energies predicted by the two models.

Dimensional and correlation effects of charged excitons in low-dimensional semiconductors

International Nuclear Information System (INIS)

Roennow, Troels F; Pedersen, Thomas G; Cornean, Horia D

2010-01-01

In this paper, we investigate the existence of bound trion states in fractional dimensional nanostructures, in terms of variational calculus. We start with trial states, then we refine the result with the help of the Hartree-Fock approximation and finally we use a partial basis expansion. We show that Hartree-Fock significantly underestimates the trion binding energy and that the correlation energy is comparable with the trion binding energy. Furthermore we calculate the binding energies of positive and negative trions restricted to a large subspace of functions, which we expect to span the low-lying eigenstates of the full Hamiltonian. We find that the difference between the positive and negative trion binding energies varies very little for the electron-hole mass fractions m e /m h = σ in [0.8; 1.0] and that the difference between the positive and negative trion energies grows as the dimension decreases. Finally, we compare a cylindrical effective-mass model of a typical carbon nanotube, with a fractional dimensional model with D = 1.71. We find very good agreement between the trion binding energies predicted by the two models.

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

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

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 ...

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

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

Three-dimensional organization of vestibular related eye movements to rotational motion in pigeons

Science.gov (United States)

Dickman, J. D.; Beyer, M.; Hess, B. J.

2000-01-01

During rotational motions, compensatory eye movement adjustments must continually occur in order to maintain objects of visual interest as stable images on the retina. In the present study, the three-dimensional organization of the vestibulo-ocular reflex in pigeons was quantitatively examined. Rotations about different head axes produced horizontal, vertical, and torsional eye movements, whose component magnitude was dependent upon the cosine of the stimulus axis relative to the animal's visual axis. Thus, the three-dimensional organization of the VOR in pigeons appears to be compensatory for any direction of head rotation. Frequency responses of the horizontal, vertical, and torsional slow phase components exhibited high pass filter properties with dominant time constants of approximately 3 s.

MEASURING PERFORMANCE IN ORGANIZATIONS FROM MULTI-DIMENSIONAL PERSPECTIVE

Directory of Open Access Journals (Sweden)

ȘTEFĂNESCU CRISTIAN

2017-08-01

Full Text Available In turbulent financial and economic present conditions a major challenge for the general management of organizations and in particular for the strategic human resources management is to establish a clear, coherent and consistent framework in terms of measuring organizational performance and economic efficiency. This paper aims to conduct an exploratory research of literature concerning measuring organizational performance. Based on the results of research the paper proposes a multi-dimensional model for measuring organizational performance providing a mechanism that will allow quantification of performance based on selected criteria. The model will attempt to eliminate inconsistencies and incongruities of organizational effectiveness models developed by specialists from organization theory area, performance measurement models developed by specialists from accounting management area and models of measuring the efficiency and effectiveness developed by specialists from strategic management and entrepreneurship areas.

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.

Conductor gestures influence evaluations of ensemble performance

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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.

Estimate of the damage in organs induced by neutrons in three-dimensional conformal radiotherapy

International Nuclear Information System (INIS)

Benites R, J. L.; Vega C, H. R.; Uribe, M. del R.

2014-08-01

By means of Monte Carlo methods was considered the damage in the organs, induced by neutrons, of patients with cancer that receive treatment in modality of three-dimensional conformal radiotherapy (3D-CRT) with lineal accelerator Varian Ix. The objective of this work was to estimate the damage probability in radiotherapy patients, starting from the effective dose by neutrons in the organs and tissues out of the treatment region. For that a three-dimensional mannequin of equivalent tissue of 30 x 100 x 30 cm 3 was modeled and spherical cells were distributed to estimate the Kerma in equivalent tissue and the absorbed dose by neutrons. With the absorbed dose the effective dose was calculated using the weighting factors for the organ type and radiation type. With the effective dose and the damage factors, considered in the ICRP 103, was considered the probability of damage induction in organs. (Author)

Anticipatory synchronization via low-dimensional filters

International Nuclear Information System (INIS)

Pyragiene, T.; Pyragas, K.

2017-01-01

An anticipatory chaotic synchronization scheme based on a low-order all-pass filter is proposed. The filter is designed as a Padé approximation to the transfer function of an ideal delay line, which is used in a standard Voss scheme. We show that despite its simplicity, the filter works in an anticipatory scheme as well as an ideal delay line. It provides extremely small synchronization error in the whole interval of anticipation time where the anticipatory manifold is stable. The efficacy of our scheme is explained by an analytically solvable model of unidirectionally coupled unstable spirals and confirmed numerically by an example of unidirectionally coupled chaotic Rössler systems. - Highlights: • A new coupling scheme for anticipating chaotic synchronization is proposed. • The scheme consists of a drive system coupled to a low-dimensional filter. • Long-term anticipation is achieved without using time-delay terms. • An analytical treatment estimates the maximum anticipation time. • The method is verified for the Rössler system.

Anticipatory synchronization via low-dimensional filters

Energy Technology Data Exchange (ETDEWEB)

Pyragiene, T., E-mail: tatjana.pyragiene@ftmc.lt; Pyragas, K.

2017-06-15

An anticipatory chaotic synchronization scheme based on a low-order all-pass filter is proposed. The filter is designed as a Padé approximation to the transfer function of an ideal delay line, which is used in a standard Voss scheme. We show that despite its simplicity, the filter works in an anticipatory scheme as well as an ideal delay line. It provides extremely small synchronization error in the whole interval of anticipation time where the anticipatory manifold is stable. The efficacy of our scheme is explained by an analytically solvable model of unidirectionally coupled unstable spirals and confirmed numerically by an example of unidirectionally coupled chaotic Rössler systems. - Highlights: • A new coupling scheme for anticipating chaotic synchronization is proposed. • The scheme consists of a drive system coupled to a low-dimensional filter. • Long-term anticipation is achieved without using time-delay terms. • An analytical treatment estimates the maximum anticipation time. • The method is verified for the Rössler system.

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

Resonant scattering induced thermopower in one-dimensional disordered systems

Science.gov (United States)

Müller, Daniel; Smit, Wilbert J.; Sigrist, Manfred

2015-05-01

This study analyzes thermoelectric properties of a one-dimensional random conductor which shows localization effects and simultaneously includes resonant scatterers yielding sharp conductance resonances. These sharp features give rise to a distinct behavior of the Seebeck coefficient in finite systems and incorporate the degree of localization as a means to enhance thermoelectric performance, in principle. The model for noninteracting electrons is discussed within the Landauer-Büttiker formalism such that analytical treatment is possible for a wide range of properties, if a special averaging scheme is applied. The approximations in the averaging procedure are tested with numerical evaluations showing good qualitative agreement, with some limited quantitative disagreement. The validity of low-temperature Mott's formula is determined and a good approximation is developed for the intermediate temperature range. In both regimes the intricate interplay between Anderson localization due to disorder and conductance resonances of the disorder potential is analyzed.

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…

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

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

Ac-loss measurement of a DyBCO-Roebel assembled coated conductor cable (RACC)

International Nuclear Information System (INIS)

Schuller, S.; Goldacker, W.; Kling, A.; Krempasky, L.; Schmidt, C.

2007-01-01

Low ac-loss HTS cables for transport currents well above 1 kA are required for application in transformers and generators and are taken into consideration for future generations of fusion reactor coils. Coated conductors (CC) are suitable candidates for high field application at an operation temperature around 50-77 K, which is a crucial precondition for economical cooling costs. We prepared a short length of a Roebel bar cable made of industrial DyBCO coated conductor (Theva Company, Germany). Meander shaped tapes of 4 mm width with a twist pitch of 122 mm were cut from 10 mm wide CC tapes using a specially designed tool. Eleven of these strands were assembled to a cable. The electrical and mechanical connection of the tapes was achieved using a silver powder filled conductive epoxy resin. Ac-losses of a short sample in an external ac field were measured as a function of frequency and field amplitude in transverse and parallel field orientations. In addition, the coupling current time constant of the sample was directly measured

Ac-loss measurement of a DyBCO-Roebel assembled coated conductor cable (RACC)

Science.gov (United States)

Schuller, S.; Goldacker, W.; Kling, A.; Krempasky, L.; Schmidt, C.

2007-10-01

Low ac-loss HTS cables for transport currents well above 1 kA are required for application in transformers and generators and are taken into consideration for future generations of fusion reactor coils. Coated conductors (CC) are suitable candidates for high field application at an operation temperature around 50-77 K, which is a crucial precondition for economical cooling costs. We prepared a short length of a Roebel bar cable made of industrial DyBCO coated conductor (Theva Company, Germany). Meander shaped tapes of 4 mm width with a twist pitch of 122 mm were cut from 10 mm wide CC tapes using a specially designed tool. Eleven of these strands were assembled to a cable. The electrical and mechanical connection of the tapes was achieved using a silver powder filled conductive epoxy resin. Ac-losses of a short sample in an external ac field were measured as a function of frequency and field amplitude in transverse and parallel field orientations. In addition, the coupling current time constant of the sample was directly measured.

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.

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.

Development of 6.6 kV/600 A superconducting fault current limiter using coated conductors

Energy Technology Data Exchange (ETDEWEB)

Yazawa, T., E-mail: takashi.yazawa@toshiba.co.j [Toshiba Corporation, Power Systems Company (Japan); Koyanagi, K.; Takahashi, M.; Toba, K.; Takigami, H.; Urata, M. [Toshiba Corporation, Power Systems Company (Japan); Iijima, Y.; Saitoh, T. [Fujikura Ltd. (Japan); Amemiya, N. [Superconductivity Research Laboratory, ISTEC (Japan); Shiohara, Y. [Department of Electrical Engineering, Kyoto University (Japan); Ito, T. [Tokyo Gas Co., Ltd. (Japan)

2009-10-15

As one of the programs in the Ministry of Economy, Trade and Industry (METI) project regarding R and D on superconducting coated conductor, three-phase superconducting fault current limiter (SFCL) for 6.6 kV application was developed and successfully tested. The developed SFCL was mainly comprised three-phase set of current limiting coils installed in a sub-cooled nitrogen cryostat with a GM cryocooler, circuit breakers and a sequence circuit. The whole system was installed in a cubicle. Two tapes of coated conductor were wound in parallel in each coil to obtain the rated current of 72 A rms. After developing the whole SFCL system, short circuit experiments were implemented with a short circuit generator. In a three-line ground fault test, the SFCL successfully restricted the prospected short circuit current over 1.6 kA to about 800 A by the applied voltage of 6.6 kV. The SFCL was installed in a user field and connected with a gas engine generator, followed by a consecutive operation. In this program, 600 A class FCL coil, with which four coated conductor tapes were wound, was also developed. The coil showed sufficiently low AC loss at the rated current. With these results, the program attained the planned target of the fundamentals for the 6.6 kV/600 A SFCL.

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

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

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.