WorldWideScience

Sample records for superconductor hts compounds

  1. Progress in American Superconductor's HTS wire and optimization for fault current limiting systems

    Science.gov (United States)

    Malozemoff, Alexis P.

    2016-11-01

    American Superconductor has developed composite coated conductor tape-shaped wires using high temperature superconductor (HTS) on a flexible substrate with laminated metal stabilizer. Such wires enable many applications, each requiring specific optimization. For example, coils for HTS rotating machinery require increased current density J at 25-50 K. A collaboration with Argonne, Brookhaven and Los Alamos National Laboratories and several universities has increased J using an optimized combination of precipitates and ion irradiation defects in the HTS. Major commercial opportunities also exist to enhance electric power grid resiliency by linking substations with distribution-voltage HTS power cables [10]. Such links provide alternative power sources if one substation's transmission-voltage power is compromised. But they must also limit fault currents which would otherwise be increased by such distribution-level links. This can be done in an HTS cable, exploiting the superconductor-to-resistive transition when current exceeds the wires' critical J. A key insight is that such transitions are usually nonuniform; so the wire must be designed to prevent localized hot spots from damaging the wire or even generating gas bubbles in the cable causing dielectric breakdown. Analysis shows that local heating can be minimized by increasing the composite tape's total thickness, decreasing its total resistance in the normal state and decreasing its critical J. This conflicts with other desirable wire characteristics. Optimization of these conflicting requirements is discussed.

  2. An active homopolar magnetic bearing with high temperature superconductor (HTS) coils and ferromagnetic cores

    Science.gov (United States)

    Brown, G. V.; Dirusso, E.; Provenza, A. J.

    1995-01-01

    A proof-of-feasibility demonstration showed that high temperature superconductor (HTS) coils can be used in a high-load, active magnetic bearing in liquid nitrogen. A homopolar radial bearing with commercially wound HTS (Bi 2223) bias and control coils produced over 200 lb (890 N) radial load capacity (measured non-rotating) and supported a shaft to 14000 rpm. The goal was to show that HTS coils can operate stably with ferromagnetic cores in a feedback controlled system at a current density similar to that in Cu in liquid nitrogen. Design compromises permitted use of circular coils with rectangular cross section. Conductor improvements will eventually permit coil shape optimization, higher current density and higher bearing load capacity. The bias coil, wound with non-twisted, multifilament HTS conductor, required negligible power to carry its direct current. The control coils were wound with monofilament HTS sheathed in Ag. These dissipated negligible power for direct current (i.e. for steady radial load components). When an alternating current (AC) was added, the AC component dissipated power which increased rapidly with frequency and quadratically with AC amplitude. In fact at frequencies above about 2 hz, the effective resistance of the control coil conductor actually exceeds that of the silver which is in electrical parallel with the oxide superconductor. This is at least qualitatively understandable in the context of a Bean-type model of flux and current penetration into a Type II superconductor. Fortunately the dynamic currents required for bearing stability are of small amplitude. These results show that while twisted multifilament conductor is not needed for stable levitation, twisted multifilaments will be required to reduce control power for sizable dynamic loads, such as those due to unbalance.

  3. An HTS flux pump operated by directly driving a superconductor into flux flow region in the E- J curve

    Science.gov (United States)

    Geng, Jianzhao; Coombs, T. A.

    2016-09-01

    High-T c superconducting (HTS) flux pumps are capable of compensating the persistent current decay in HTS magnets without electrical contact. In this paper, following work on a low-T c superconducting self-switching flux pump, we propose a new HTS flux pump by directly driving a high-T c superconductor into the flux flow region in the E- J curve. The flux pump consists of a transformer which has a superconducting secondary winding shorted by an YBCO-coated conductor bridge. A high alternating current with a much higher positive peak value than the negative peak value is induced in the secondary winding. The current always drives the bridge superconductor into the flux flow region only at around its positive peak value, thus resulting in flux pumping. The proposed flux pump is much simpler than existing HTS flux pumps.

  4. Monitoring of HTS compound library quality via a high-resolution image acquisition and processing instrument.

    Science.gov (United States)

    Baillargeon, Pierre; Scampavia, Louis; Einsteder, Ross; Hodder, Peter

    2011-06-01

    This report presents the high-resolution image acquisition and processing instrument for compound management applications (HIAPI-CM). The HIAPI-CM combines imaging spectroscopy and machine-vision analysis to perform rapid assessment of high-throughput screening (HTS) compound library quality. It has been customized to detect and classify typical artifacts found in HTS compound library microtiter plates (MTPs). These artifacts include (1) insufficient volume of liquid compound sample, (2) compound precipitation, and (3) colored compounds that interfere with HTS assay detection format readout. The HIAPI-CM is also configured to automatically query and compare its analysis results to data stored in a LIMS or corporate database, aiding in the detection of compound registration errors. To demonstrate its capabilities, several compound plates (n=5760 wells total) containing different artifacts were measured via automated HIAPI-CM analysis, and results compared with those obtained by manual (visual) inspection. In all cases, the instrument demonstrated high fidelity (99.8% empty wells; 100.1% filled wells; 94.4% for partially filled wells; 94.0% for wells containing colored compounds), and in the case of precipitate detection, the HIAPI-CM results significantly exceeded the fidelity of visual observations (220.0%). As described, the HIAPI-CM allows for noninvasive, nondestructive MTP assessment with a diagnostic throughput of about 1min per plate, reducing analytical expenses and improving the quality and stewardship of HTS compound libraries.

  5. Development of HTS Transformers and a 10 kVA HTS Transformer Prototype Design

    Institute of Scientific and Technical Information of China (English)

    Xiao-Yuan Chen; Jian-Xun Jin

    2008-01-01

    With the improvement of high temperature superconductor (HTS) practical performance, research and development concerning the applications of HTS transformers have been progressed actively worldwide. This paper provides a comprehensive summary on various HTS transformers, and studies the design of a single-phase 10 kVA (220V/24V) HTS trans- former prototype to verify HTS for practical transformer applications.

  6. Experimental study on the double-evaporator thermosiphon for cooling HTS (high temperature superconductor) system

    Science.gov (United States)

    Lee, Junghyun; Ko, Junseok; Kim, Youngkwon; Jeong, Sangkwon; Sung, Taehyun; Han, Younghee; Lee, Jeong-Phil; Jung, Seyong

    2009-08-01

    A cryogenic thermosiphons is an efficient heat transfer device between a cryocooler and a thermal load that is to be cooled. This paper presents an idea of thermosiphon which contains two vertically-separated evaporators. This unique configuration of the thermosiphon is suitable for the purpose of cooling simultaneously two superconducting bearings of the HTS (high temperature superconducting) flywheel system at the same temperature. A so-called double-evaporator thermosiphon was designed, fabricated and tested using nitrogen as the working fluid under sub-atmospheric pressure condition. The interior thermal condition of the double-evaporator thermosiphon was examined in detail during its cool-down process according to the internal thermal states. The double-evaporator thermosiphon has operated successfully at steady-state operation under sub-atmospheric pressure. At the heat flow of 10.6 W, the total temperature difference of the thermosiphon was only 1.59 K and the temperature difference between the evaporators was 0.64 K. The temperature difference of two evaporators is attributed to the conductive thermal resistance of the adiabatic section between the evaporators. The method to reduce this temperature difference has been investigated and presented in this paper. The proper area selection of condenser, evaporator 1, and evaporator 2 was studied by using thermal resistance model to optimize the performance of a thermosiphon. The superior heat transfer characteristic of the double-evaporator thermosiphon without involving any cryogenic pump can be a great potential advantage for cooling HTS bulk modules that are separated vertically.

  7. Identification of compounds that modulate retinol signaling using a cell-based qHTS assay.

    Science.gov (United States)

    Chen, Yanling; Sakamuru, Srilatha; Huang, Ruili; Reese, David H; Xia, Menghang

    2016-04-01

    In vertebrates, the retinol (vitamin A) signaling pathway (RSP) controls the biosynthesis and catabolism of all-trans retinoic acid (atRA), which regulates transcription of genes essential for embryonic development. Chemicals that interfere with the RSP to cause abnormal intracellular levels of atRA are potential developmental toxicants. To assess chemicals for the ability to interfere with retinol signaling, we have developed a cell-based RARE (Retinoic Acid Response Element) reporter gene assay to identify RSP disruptors. To validate this assay in a quantitative high-throughput screening (qHTS) platform, we screened the Library of Pharmacologically Active Compounds (LOPAC) in both agonist and antagonist modes. The screens detected known RSP agonists, demonstrating assay reliability, and also identified novel RSP agonists including kenpaullone, niclosamide, PD98059 and SU4312, and RSP antagonists including Bay 11-7085, LY294002, 3,4-Methylenedioxy-β-nitrostyrene, and topoisomerase inhibitors (camptothecin, topotecan, amsacrine hydrochloride, and idarubicin). When evaluated in the P19 pluripotent cell, these compounds were found to affect the expression of the Hoxa1 gene that is essential for embryo body patterning. These results show that the RARE assay is an effective qHTS approach for screening large compound libraries to identify chemicals that have the potential to adversely affect embryonic development through interference with retinol signaling.

  8. Alternative HTS coated conductors

    Science.gov (United States)

    Blaugher, R. D.; Bhattacharya, R. N.; Chen, J.; Padmanabhan, R.

    2002-10-01

    The availability of Bi-2223 high-temperature-superconductor (HTS) powder-in-tube (PIT) tape, with acceptable performance for long lengths, has provided the ability to construct a wide range of HTS electric power components. As a result, there are major worldwide projects in developing HTS electric power components for demonstration in a utility environment. Utility acceptance for superconducting power equipment will depend on several key factors: improved system performance, lower life-cycle costs, higher efficiency versus conventional technology, reliability and maintenance comparable to conventional power equipment, and a competitive installed cost. The latter is impacted by the current high cost of HTS conductors, which must be lowered to costs comparable to conventional Nb-Ti wire, i.e., $2-5/kAm. The present performance and cost of state-of-the-art Bi-2223 HTS tape, although acceptable for prototype construction, is viewed as a major deterrent that may compromise eventual commercialization for most of these electric power devices. The so-called second-generation coated conductor development, with emphasis on conductors employing HTS YBCO films, is viewed as the solution to this performance and cost issue. The potential for the Tl, Hg, and Bi-oxide superconductors for producing an HTS tape as alternatives to Bi-2223 PIT (and YBCO) will be discussed with some recent results on Bi-2212 “coated conductor” development.

  9. Novel HTS strategy identifies TRAIL-sensitizing compounds acting specifically through the caspase-8 apoptotic axis.

    Directory of Open Access Journals (Sweden)

    Darren Finlay

    Full Text Available Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL is potentially a very important therapeutic as it shows selectivity for inducing apoptosis in cancer cells whilst normal cells are refractory. TRAIL binding to its cognate receptors, Death Receptors-4 and -5, leads to recruitment of caspase-8 and classical activation of downstream effector caspases, leading to apoptosis. As with many drugs however, TRAIL's usefulness is limited by resistance, either innate or acquired. We describe here the development of a novel 384-well high-throughput screening (HTS strategy for identifying potential TRAIL-sensitizing agents that act solely in a caspase-8 dependent manner. By utilizing a TRAIL resistant cell line lacking caspase-8 (NB7 compared to the same cells reconstituted with the wild-type protein, or with a catalytically inactive point mutant of caspase-8, we are able to identify compounds that act specifically through the caspase-8 axis, rather than through general toxicity. In addition, false positive hits can easily be "weeded out" in this assay due to their activity in cells lacking caspase-8-inducible activity. Screening of the library of pharmacologically active compounds (LOPAC was performed as both proof-of-concept and to discover potential unknown TRAIL sensitizers whose mechanism is caspase-8 mediated. We identified known TRAIL sensitizers from the library and identified new compounds that appear to sensitize specifically through caspase-8. In sum, we demonstrate proof-of-concept and discovery of novel compounds with a screening strategy optimized for the detection of caspase-8 pathway-specific TRAIL sensitizers. This screen was performed in the 384-well format, but could easily be further miniaturized, allows easy identification of artifactual false positives, and is highly scalable to accommodate diverse libraries.

  10. Advances in HTS materials

    CERN Document Server

    Tixador, P

    2009-01-01

    HTS (High Temperature Superconductor) offer great opportunities to reach higher magnetic flux densities when compared with LTS (Low Temperature Superconductor). The upper generally accepted limit of 23 T using Nb3Sn can be overstep with HTS. HTS Bi-2212 round wires have shown critical current densities as higher than 1000 MA/m2 under 45 T at 4.2 K. The road for very high fields is open. The round shape suits rather well for magnets, especially with high current specifications since the “classical” high current cables (Rutherford, CIC) require elementary round conductor. The absence of current anisotropy in round conductor is another advantage. The YBaCuO coated conductors (HTS second generation conductors) show large opportunities for high fields. Their higher mechanical performances (IBAD process) compared to Bi conductor bring advantages for high field magnets. The protection of HTS magnet is an identified issue since degradations have been observed in several magnets after a quench. A state of the art ...

  11. High-Tc Superconductors Based on FeAs Compounds

    CERN Document Server

    Izyumov, Yuri

    2010-01-01

    Physical properties and models of electronic structure are analyzed for a new class of high-TC superconductors which belong to iron-based layered compounds. Despite their variable chemical composition and differences in the crystal structure, these compounds possess similar physical characteristics, due to electron carriers in the FeAs layers and the interaction of these carriers with fluctuations of the magnetic order. A tremendous interest towards these materials is explained by the prospects of their practical use. In this monograph, a full picture of the formation of physical properties of these materials, in the context of existing theory models and electron structure studies, is given. The book is aimed at a broad circle of readers: physicists who study electronic properties of the FeAs compounds, chemists who synthesize them and specialists in the field of electronic structure calculations in solids. It is helpful not only to researchers active in the fields of superconductivity and magnetism, but also...

  12. Towards the Design of Power Switches Utilizing HTS Material

    CERN Document Server

    March, S A; Beduz, C; Mess, K H; Yang, Y

    2008-01-01

    Conventional superconducting switches for power applications, which operate at liquid helium temperature, generally utilize Nb-Ti superconductor in a cupro-nickel matrix. For superconducting circuits based on High Temperature Superconductors (HTS) that work at higher temperatures, the associated superconducting switches must also be based on HTS. This paper addresses the issues concerning the requirements and the appropriate design of HTS switches, including approaches to fast triggering.

  13. High temperature superconductor accelerator magnets

    NARCIS (Netherlands)

    van Nugteren, J.

    2016-01-01

    For future particle accelerators bending dipoles are considered with magnetic fields exceeding 20T. This can only be achieved using high temperature superconductors (HTS). These exhibit different properties from classical low temperature superconductors and still require significant research and dev

  14. INVESTIGATION OF EMPIRICAL LAWS FOR SUPERCONDUCTIVITY OF ALLOY AND COMPOUND SUPERCONDUCTORS

    Institute of Scientific and Technical Information of China (English)

    刘隆鉴; 章壮健

    2001-01-01

    By studying the average effect of the electronegativity of alloy and compound superconductors, some empirical laws are found. The average value of the electronegativity of alloy superconductors x is from 1.3 to 1.9, most of which is concentrated in the region 1.5 < x < 1.8. The x of many higher Tc superconductors is nearly 1.60. All these characteristics are similar to element superconductors. The average value of the electronegativity η of positive valence elements in oxide superconductors is from 1.3 to 1.6, and the average effect of an electronegativity of zero on every element is from 1.75 to 2.00. The mean of η and is from 1.5 to 1.8. When both η and are near the limit value (1.3 or 1.6 and 1.75 or 2.00), the material has a very low Tc, even is non-superconductive. The η of other compound superconductors is either too high or too low, and the is too low so that the Tc of these superconductors is quite low.Studying the average effect of the electronegativity of non-superconducting compounds further confirms the laws.

  15. High Tc Superconductor Theoretical Models and Electromagnetic Flux Characteristics

    Institute of Scientific and Technical Information of China (English)

    JIN Jian-xun

    2006-01-01

    High Tc Superconductors (HTS) have special electromagnetic characteristics and phenomena. Effort has been made in order to theoretically understand the applied HTS superconductivity and HTS behaviors for practical applications, various theoretical models related to the HTS electromagnetic properties have been developed. The theoretical models and analytic methods are summarized with regard to understanding the HTS magnetic flux characteristic which is one of the most critical issues related to HTS applications such as for HTS magnetic levitation application.

  16. Superconductors

    CERN Document Server

    Narlikar, A V

    2014-01-01

    Superconductors is neither about basic aspects of superconductivity nor about its applications, but its mainstay is superconducting materials. Unusual and unconventional features of a large variety of novel superconductors are presented and their technological potential as practical superconductors assessed. The book begins with an introduction to basic aspects of superconductivity. The presentation is readily accessible to readers from a diverse range of scientific and technical disciplines, such as metallurgy, materials science, materials engineering, electronic and device engineering, and chemistry. The derivation of mathematical formulas and equations has been kept to a minimum and, wherever necessary, short appendices with essential mathematics have been added at the end of the text. The book is not meant to serve as an encyclopaedia, describing each and every superconductor that exists, but focuses on important milestones in their exciting development.

  17. HTS Insert Magnet Design Study

    CERN Document Server

    Devaux, M; Fleiter, J; Fazilleau, P; Lécrevisse, T; Pes, C; Rey, J-M; Rifflet, J-M; Sorbi, M; Stenvall, A; Tixador, P; Volpini, G

    2011-01-01

    Future accelerator magnets will need to reach higher field in the range of 20 T. This field level is very difficult to reach using only Low Temperature Superconductor materials whereas High Temperature Superconductors (HTS) provide interesting opportunities. High current densities and stress levels are needed to design such magnets. YBCO superconductor indeed carries large current densities under high magnetic field and provides good mechanical properties especially when produced using the IBAD approach. The HFM EUCARD program studies the design and the realization of an HTS insert of 6 T inside a Nb3Sn dipole of 13T at 4.2 K. In the2HTS insert, engineering current densities higher than 250 MA/m under 19 T are required to fulfill the specifications. The stress level is also very severe. YBCO IBAD tapes theoretically meet these challenges from presented measurements. The insert protection is also a critical because HTS materials show low quench propagation velocities and the coupling with the Nb3Sn magnet make...

  18. High Temperature Superconductor Machine Prototype

    DEFF Research Database (Denmark)

    Mijatovic, Nenad; Jensen, Bogi Bech; Træholt, Chresten

    2011-01-01

    A versatile testing platform for a High Temperature Superconductor (HTS) machine has been constructed. The stationary HTS field winding can carry up to 10 coils and it is operated at a temperature of 77K. The rotating armature is at room temperature. Test results and performance for the HTS field...

  19. Application Fields of High-Temperature Superconductors

    OpenAIRE

    Hott, Roland

    2003-01-01

    Potential application fields for cuprate high-temperature superconductors (HTS) and the status of respective projects are reviewed. The availability of a reliable and inexpensive cooling technique will be essential for a future broad acceptance of HTS applications.

  20. Development of CXCR4 modulators by virtual HTS of a novel amide-sulfamide compound library.

    Science.gov (United States)

    Bai, Renren; Shi, Qi; Liang, Zhongxing; Yoon, Younghyoun; Han, Yiran; Feng, Amber; Liu, Shuangping; Oum, Yoonhyeun; Yun, C Chris; Shim, Hyunsuk

    2017-01-27

    CXCR4 plays a crucial role in recruitment of inflammatory cells to inflammation sites at the beginning of the disease process. Modulating CXCR4 functions presents a new avenue for anti-inflammatory strategies. However, using CXCR4 antagonists for a long term usage presents potential serious side effect due to their stem cell mobilizing property. We have been developing partial CXCR4 antagonists without such property. A new computer-aided drug design program, the FRESH workflow, was used for anti-CXCR4 lead compound discovery and optimization, which coupled both compound library building and CXCR4 docking screens in one campaign. Based on the designed parent framework, 30 prioritized amide-sulfamide structures were obtained after systemic filtering and docking screening. Twelve compounds were prepared from the top-30 list. Most synthesized compounds exhibited good to excellent binding affinity to CXCR4. Compounds Ig and Im demonstrated notable in vivo suppressive activity against xylene-induced mouse ear inflammation (with 56% and 54% inhibition). Western blot analyses revealed that Ig significantly blocked CXCR4/CXCL12-mediated phosphorylation of Akt. Moreover, Ig attenuated the amount of TNF-α secreted by pathogenic E. coli-infected macrophages. More importantly, Ig had no observable cytotoxicity. Our results demonstrated that FRESH virtual high throughput screening program of targeted chemical class could successfully find potent lead compounds, and the amide-sulfamide pharmacophore was a novel and effective framework blocking CXCR4 function.

  1. HTS axial flux induction motor with analytic and FEA modeling

    Science.gov (United States)

    Li, S.; Fan, Y.; Fang, J.; Qin, W.; Lv, G.; Li, J. H.

    2013-11-01

    This paper presents a high-temperature superconductor (HTS) axial-flux induction motor, which can output levitation force and torque simultaneously. In order to analyze the character of the force, analytic method and finite element method are adopted to model the motor. To make sure the HTS can carry sufficiently large current and work well, the magnetic field distribution in HTS coil is calculated. An effective method to improve the critical current of HTS coil is presented. Then, AC losses in HTS windings in the motor are estimated and tested.

  2. Photoemission search for an RVB state in novel thallium-compound high-temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Hwu, Y.; Marsi, M.; Terrasi, A.; Onellion, M.; Huber, D.L.; Margaritondo, G. (University of Wisconsin-Madison, Stoughton, Wisconsin 53589-3097 (USA)); Wang, J.H.; Sheng, Z.Z.; Hermann, A.M. (Department of Physics, University of Arkansas, Fayetteville, AK (USA))

    1990-01-25

    We used photoemission spectroscopy with synchrotron radiation to search for evidence of a resonating valence bond (RVB) state in a series of thallium-containing high-temperature superconductors. As in the case of Bi compounds, no positive evidence was found, and the data imply a low upper limit for the energy of hypothetical spinons.

  3. Photoemission search for an RVB state in novel thallium-compound high-temperature superconductors

    Science.gov (United States)

    Hwu, Y.; Marsi, M.; Terrasi, A.; Onellion, M.; Huber, D. L.; Margaritondo, G.; Wang, J. H.; Sheng, Z. Z.; Hermann, A. M.

    1990-01-01

    We used photoemission spectroscopy with synchrotron radiation to search for evidence of a resonating valence bond (RVB) state in a series of thallium-containing high-temperature superconductors. As in the case of Bi compounds, no positive evidence was found, and the data imply a low upper limit for the energy of hypothetical spinons.

  4. Virtual high throughput screening (vHTS) - A perspective

    OpenAIRE

    Subramaniam, Sangeetha; Mehrotra, Monica; Gupta, Dinesh,

    2008-01-01

    With the exponential rise in the number of viable novel drug targets, computational methods are being increasingly applied to accelerate the drug discovery process. Virtual High Throughput Screening (vHTS) is one such established methodology to identify drug candidates from large collection of compound libraries. Although it complements the expensive and time consuming High Throughput Screening (HTS) of compound libraries, vHTS possess inherent challenges. The successful vHTS requires the car...

  5. Second-generation HTS conductors

    CERN Document Server

    2010-01-01

    The discovery of high temperature superconductors (HTS) in 1986 by two IBM scientists led to an unprecedented explosion of research and development efforts world-wide because of the significant potential for practical applications offered by these materials. However, the early euphoria created by the exciting prospects was dampened by the daunting task of fabricating these materials into useful forms with acceptable superconducting properties. Progress towards this goal has been hindered by many intrinsic materials problems, such as weak-links, flux-creep, and poor mechanical properties. The above problems led to the development of the Second-Generation of HTS wires. Three methods were invented to produce flexible metallic substrates, which were also crystallographically biaxially textured, and resembled a long, mosaic single crystal. The first method invented is the Ion-Beam-Assisted-Deposition (IBAD). The second method developed was the Inclined-Substrate-Deposition (ISD). The third method invented is calle...

  6. HTS machine laboratory prototype

    DEFF Research Database (Denmark)

    many of HTS properties are not known and need to be tested with a specific purpose in mind not just for different types of HTS conductors but also for the same type of HTS conductors made by different manufactures. To address some of these challenges, we have constructed a laboratory prototype HTS...

  7. HTS axial flux induction motor with analytic and FEA modeling

    Energy Technology Data Exchange (ETDEWEB)

    Li, S., E-mail: alexlee.zn@gmail.com; Fan, Y.; Fang, J.; Qin, W.; Lv, G.; Li, J.H.

    2013-11-15

    Highlights: •A high temperature superconductor axial flux induction motor and a novel maglev scheme are presented. •Analytic method and finite element method have been adopted to model the motor and to calculate the force. •Magnetic field distribution in HTS coil is calculated by analytic method. •An effective method to improve the critical current of HTS coil is presented. •AC losses of HTS coils in the HTS axial flux induction motor are estimated and tested. -- Abstract: This paper presents a high-temperature superconductor (HTS) axial-flux induction motor, which can output levitation force and torque simultaneously. In order to analyze the character of the force, analytic method and finite element method are adopted to model the motor. To make sure the HTS can carry sufficiently large current and work well, the magnetic field distribution in HTS coil is calculated. An effective method to improve the critical current of HTS coil is presented. Then, AC losses in HTS windings in the motor are estimated and tested.

  8. Momentum-resolved electronic structure of the superconductor parent compound BaBiO3

    Science.gov (United States)

    Plumb, N. C.; Ristic, Z.; Park, J.; Wang, Z.; Matt, C. E.; Xu, N.; Lv, B. Q.; Gawryluk, D.; Pomjakushina, E.; Conder, K.; Wang, Y.; Johnston, S.; Mesot, J.; Shi, M.; Radovic, M.

    We use in situ angle-resolved photoemission to study thin films of BaBiO3, a parent compound of bismuthate superconductors with Tc up to 30 K. By simple electron counting, BaBiO3 should be metallic. However, in analogy with many unconventional and high-Tc superconductor families, it is instead insulating, and superconductivity emerges with doping. Our experiments reveal a folded band structure consistent with known BiO6 breathing distortions. However, charge ordering often thought to accompany the distortions is virtually nonexistent. The data combined with DFT calculations indicate that states near EF are primarily oxygen-derived. Hence BaBiO3 appears to be characterized by negative charge transfer energy. This can account for the seeming discrepancy between the atomic structure and ''missing'' charge order. It should also be relevant for understanding the doping evolution and superconductivity in bismuthates.

  9. Second-generation HTS conductors

    CERN Document Server

    Goyal, Amit

    2006-01-01

    The discovery of high temperature superconductors (HTS) in 1986 by two IBM scientists led to an unprecedented explosion of research and development efforts world-wide because of the significant potential for practical applications offered by these materials. However, the early euphoria created by the exciting prospects was dampened by the daunting task of fabricating these materials into useful forms with acceptable superconducting properties. Progress towards this goal has been hindered by many intrinsic materials problems, such as weak-links, flux-creep, and poor mechanical properties.

  10. Applications of bulk high-temperature superconductors

    Science.gov (United States)

    Hull, J. R.

    The development of high-temperature superconductors (HTS's) can be broadly generalized into thin-film electronics, wire applications, and bulk applications. We consider bulk HTS's to include sintered or crystallized forms that do not take the geometry of filaments or tapes, and we discuss major applications for these materials. For the most part applications may be realized with the HTS's cooled to 77 K, and the properties of the bulk HTS's are often already sufficient for commercial use. A non-exhaustive list of applications for bulk HTS's includes trapped field magnets, hysteresis motors, magnetic shielding, current leads, and magnetic bearings. These applications are briefly discussed in this paper.

  11. 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....

  12. Features and Prototypes of HTS High Q Resonant Circuit

    Institute of Scientific and Technical Information of China (English)

    Jian-Xun Jin

    2007-01-01

    High Tc superconductor (HTS) technology has been used to develop a unique high Q resonant circuit. Such circuit or device has some special characteristics such as very high voltage generation. Theoretical study and experimental approaches have proceeded for the concept verification. This paper presents the theory about this high Q resonant circuit. The operation principle of the circuit is described. A practical prototype for HTS high voltage generation is also demonstrated. The experiment result shows that very high voltages can be achieved by the developed method using HTS technology.

  13. Upgrade of SULTAN/EDIPO for HTS Cable Test

    Science.gov (United States)

    Wesche, R.; Bruzzone, P.; Uglietti, D.; Bykovsky, N.; Lewandowska, M.

    CRPP hosts two unique conductor test facilities SULTAN (SUpraLeiter TestANlage) and EDIPO (European DIPOle). They allow the test of high current superconductors in high magnetic fields (SULTAN 11 T, EDIPO 12.5 T). In both facilities sample currents up to 100 kA can be supplied by means of a NbTi transformer. Presently the facilities are upgraded for the test of high current high-temperature superconductor (HTS) samples. For HTS conductor testing at temperatures between 20 and 50 K, the heat flux between the HTS sample under test and the NbTi transformer needs to be limited to around 10 W per conductor leg by means of an HTS adapter connecting them. The second required upgrade is the supply of intermediate temperature helium (20-50 K) to the HTS test conductor. It is mandatory that the helium gas coming from the HTS conductor under test can be returned to the cryoplant as cold gas (T < 20 K). To reach this goal a tube-in-tube heat exchanger has been manufactured in which 4.5 K helium coming from the cryoplant is in counter flow with the warm gas leaving the HTS test conductor.

  14. Manufacturing of Superconductors

    DEFF Research Database (Denmark)

    Bech, Jakob Ilsted; Bay, Niels

    Superconducting tapes based on the ceramic high temperature superconductor (HTS) is a new promising product for high current applications such as electro-magnets and current transmission cables. The tapes are made by the oxide powder in tube (OPIT) method implying drawing and rolling of silver tu...

  15. Improvement in Superconducting Properties of MgB2 Superconductors by Nanoscale Carbon-Based Compound Doping

    Institute of Scientific and Technical Information of China (English)

    Si-Hai Zhou

    2008-01-01

    MgB2 is a relatively new superconductor; it has attracted great interest from superconductor researchers all over the world. Thorough investigations have been carried out to study the material fabrication, as well as to study the material and superconducting properties from a fundamental physics point of view. The University of Wollongong has played a very active role in this research and a leading role in the research on high critical current density and high critical magnetic fields. Our recent research on the improve- ment of critical current density and the upper critical magnetic field by carbon-based compound doping is reviewed in this paper.

  16. American superconductor technology to help CERN to explore the mysteries of matter company's high temperature superconductor wire to be used in CERN's Large Hadron Collider

    CERN Multimedia

    2003-01-01

    American Superconductor Corporation has been selected by CERN, to provide 14,000 meters of high temperature superconductor (HTS) wire for current lead devices that will be used in CERN's Large Hadron Collider (1 page).

  17. Theory of AC Loss in Cables with 2G HTS Wire

    Energy Technology Data Exchange (ETDEWEB)

    Clem, J.R.; Malozemoff, A.P.

    2009-09-13

    While considerable work has been done to understand AC losses in power cables made of first generation (1G) high temperature superconductor (HTS) wires, use of second generation (2G) HTS wires brings in some new considerations. The high critical current density of the HTS layer 2G wire reduces the surface superconductor hysteretic losses. Instead, gap and polygonal losses, flux transfer losses in imbalanced two layer cables and ferromagnetic losses for wires with NiW substrates constitute the principal contributions. Current imbalance and losses associated with the magnetic substrate can be minimized by orienting the substrates of the inner winding inward and the outer winding outward.

  18. Critical current studies of a HTS rectangular coil

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Z. [Department of Engineering, University of Cambridge (United Kingdom); Chudy, M., E-mail: Michal.chudy@stuba.sk [Graduate School of Technology Management, University of Pretoria (South Africa); Institute of Power and Applied Electrical Engineering, Slovak University of Technology in Bratislava (Slovakia); Ruiz, H.S. [Department of Engineering, University of Leicester, Leicester LE1 7RH (United Kingdom); Zhang, X.; Coombs, T. [Department of Engineering, University of Cambridge (United Kingdom)

    2017-05-15

    Highlights: • Unique square pancake coil was manufactured. • Measurements in relatively high magnetic field were performed. • Different sections of the coil were characterized. • Parts of the coil which are limiting critical current were identified. - Abstract: Nowadays, superconducting high field magnets are used in numerous applications due to their superior properties. High temperature superconductors (HTS) are usually used for production of circular pancake or racetrack coils. However different geometries of HTS coils might be required for some specific applications. In this study, the HTS coil wound on a rectangular frame was fully characterized in homogeneous DC background field. The study contains measurements of critical current angular dependencies. The critical current of the entire coil and two selected strands under different magnitudes and orientations of external magnetic fields are measured. The critical regions of the coil in different angular regimes are determined. This study brings better understanding of the in- field performance of HTS coils wound on frames with right-angles.

  19. Levitation characteristics of HTS tape stacks

    Energy Technology Data Exchange (ETDEWEB)

    Pokrovskiy, S. V.; Ermolaev, Y. S.; Rudnev, I. A. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation)

    2015-03-15

    Due to the considerable development of the technology of second generation high-temperature superconductors and a significant improvement in their mechanical and transport properties in the last few years it is possible to use HTS tapes in the magnetic levitation systems. The advantages of tapes on a metal substrate as compared with bulk YBCO material primarily in the strength, and the possibility of optimizing the convenience of manufacturing elements of levitation systems. In the present report presents the results of the magnetic levitation force measurements between the stack of HTS tapes containing of tapes and NdFeB permanent magnet in the FC and ZFC regimes. It was found a non- linear dependence of the levitation force from the height of the array of stack in both modes: linear growth at small thickness gives way to flattening and constant at large number of tapes in the stack. Established that the levitation force of stacks comparable to that of bulk samples. The numerical calculations using finite element method showed that without the screening of the applied field the levitation force of the bulk superconductor and the layered superconductor stack with a critical current of tapes increased by the filling factor is exactly the same, and taking into account the screening force slightly different.

  20. An HTS machine laboratory prototype

    DEFF Research Database (Denmark)

    Mijatovic, Nenad; Jensen, Bogi Bech; Træholt, Chresten

    2012-01-01

    This paper describes Superwind HTS machine laboratory setup which is a small scale HTS machine designed and build as a part of the efforts to identify and tackle some of the challenges the HTS machine design may face. One of the challenges of HTS machines is a Torque Transfer Element (TTE) which...

  1. Structural phase transitions in high-temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Tatarenko, H.M. [Toulon Univ., 83 - Le Garde (France). Lab. des Materiaux Multiphases et Interfaces; Nihoul, G.E. [Toulon Univ., 83 - Le Garde (France). Lab. des Materiaux Multiphases et Interfaces

    1995-11-01

    This chapter is devoted to the study of the order-disorder like phase transitions which occur in the high-temperature superconductors (HTS). We mainly consider Lanthanium based compounds like La{sub 2}CuO{sub 4+{delta}} or La{sub 2-x}M{sub x}CuO{sub 4+{delta}} (where M is an alkali atom Ba, Sr, Ca, Na, K, ..) and Yttrium based superconductors like YBa{sub 2}Cu{sub 3}O{sub 6+{delta}}. Different kinds of ordered structures were found in these compounds by X-ray and neutron diffraction, as well as by High Resolution Electron Microscopy imaging and are described. The theoretical models, which describe the structural evolution as temperature and/or concentration of the different components vary, are considered in detail. The relation between structural instabilities and high-temperature superconductivity is discussed. (orig.)

  2. Test Results For a 25-m Prototype Fault Current Limiting HTS Cable for Project Hydra

    Energy Technology Data Exchange (ETDEWEB)

    Rey, Christopher M [ORNL; Duckworth, Robert C [ORNL; Demko, Jonathan A [ORNL; Ellis, Alvin R [ORNL; Gouge, Michael J [ORNL; James, David Randy [ORNL; Tuncer, Enis [ORNL

    2010-01-01

    The Oak Ridge National Laboratory (ORNL) has tested a 25-m long prototype High Temperature Superconducting (HTS) cable with inherent Fault-Current Limiting (FCL) capability at its recently upgraded HTS cable test facility in Oak Ridge, TN. The HTS-FCL cable and terminations were designed and fabricated by Ultera, which is a joint venture of Southwire and nkt cables with FCL features and HTS wire provided by American Superconductor Corporation. The overall project is sponsored by the U.S. Department of Homeland Security. The ultimate goal of the 25-m HTS-FCL cable test program was to verify the design and ensure the operational integrity for the eventual installation of a ~ 200-m fully functional HTS-FCL cable in the Consolidated Edison electric grid located in downtown New York City. The 25-m HTS-FCL cable consisted of a three-phase (3- ) Triax design with a cold dielectric between the phases. The HTS-FCL cable had an operational voltage of 13.8 kV phase-to-phase and an operating current of 4000 Arms per phase, which is the highest operating current to date of any HTS cable. The 25-m HTS-FCL cable was subjected to a series of cryogenic and electrical tests. Test results from the 25-m HTS-FCL cable are presented and discussed.

  3. Aeronautical applications of high-temperature superconductors

    Science.gov (United States)

    Turney, George E.; Luidens, Roger W.; Uherka, Kenneth; Hull, John

    1989-01-01

    The successful development of high-temperature superconductors (HTS) could have a major impact on future aeronautical propulsion and aeronautical flight vehicle systems. A preliminary examination of the potential application of HTS for aeronautics indicates that significant benefits may be realized through the development and implementation of these newly discovered materials. Applications of high-temperature superconductors (currently substantiated at 95 k) were envisioned for several classes of aeronautical systems, including subsonic and supersonic transports, hypersonic aircraft, V/STOL aircraft, rotorcraft, and solar, microwave and laser powered aircraft. Introduced and described are the particular applications and potential benefits of high-temperature superconductors as related to aeronautics and/or aeronautical systems.

  4. Aeronautical applications of high-temperature superconductors

    Science.gov (United States)

    Turney, George E.; Luidens, Roger W.; Uherka, Kenneth; Hull, John

    1989-01-01

    The successful development of high-temperature superconductors (HTS) could have a major impact on future aeronautical propulsion and aeronautical flight vehicle systems. A preliminary examination of the potential application of HTS for aeronautics indicates that significant benefits may be realized through the development and implementation of these newly discovered materials. Applications of high-temperature superconductors (currently substantiated at 95 K) were envisioned for several classes of aeronautical systems, including subsonic and supersonic transports, hypersonic aircraft, V/STOL aircraft, rotorcraft, and solar, microwave and laser powered aircraft. Introduced and described are the particular applications and potential benefits of high-temperature superconductors as related to aeronautics and/or aeronautical systems.

  5. Harmonic analysis and field quality improvement of an HTS quadrupole magnet for a heavy ion accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhan; Wei, Shaoqing; Lee, Sang Jin [Uiduk University, Gyeongju (Korea, Republic of); Jo, Hyun Chul; Kim, Do Gyun; Kim, Jong Won [Rare Isotope Science Project, Institute for Basic Science, Daejeon (Korea, Republic of)

    2016-06-15

    In recent years, the iron-dominated high-temperature superconductor (HTS) quadrupole magnets are being developed for heavy ion accelerators. Field analyses for iron-dominated quadrupole magnets were based on the normal-conducting (NC) quadrupole magnet early in the development for accelerators. Some conclusions are still in use today. However, the magnetic field of iron-dominated HTS quadrupole magnets cannot fully follow these conclusions. This study established an HTS quadrupole magnet model and an NC quadrupole magnet model, respectively. The harmonic characteristics of two magnets were analyzed and compared. According to the comparison, the conventional iron-dominated quadrupole magnets can be designed for maximum field gradient; the HTS quadrupole magnet, however, should be considered with varying field gradient. Finally, the HTS quadrupole magnet was designed for the changing field gradient. The field quality of the design was improved comparing with the result of the previous study. The new design for the HTS quadrupole magnet has been suggested.

  6. HTS thin films: Passive microwave components and systems integration issues

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, F.A.; Chorey, C.M.; Bhasin, K.B. [National Aeronautics and Space Administration, Cleveland, OH (United States)

    1994-12-31

    The excellent microwave properties of the High-Temperature-Superconductors (HTS) have been amply demonstrated in the laboratory by techniques such as resonant cavity, power transmission and microstrip resonator measurements. The low loss and high Q passive structures made possible with HTS, present attractive options for applications in commercial, military and space-based systems. However, to readily insert HTS into these systems improvement is needed in such areas as repeatability in the deposition and processing of the HTS films, metal-contact formation, wire bonding, and overall film endurance to fabrication and assembly procedures. In this paper we present data compiled in our lab which illustrate many of the problems associated with these issues. Much of this data were obtained in the production of a space qualified hybrid receiver-downconverter module for the Naval Research Laboratory`s High Temperature Superconductivity Space Experiment II (HTSSE-II). Examples of variations observed in starting films and finished circuits will be presented. It is shown that under identical processing the properties of the HTS films can degrade to varying extents. Finally, we present data on ohmic contacts and factors affecting their adhesion to HTS films, strength of wire bonds made to such contacts, and aging effects.

  7. Mössbauer studies of the peculiar magnetism in parent compounds of the iron-based superconductors

    Science.gov (United States)

    Jasek, A. K.; Komędera, K.; Błachowski, A.; Ruebenbauer, K.; Żukrowski, J.; Bukowski, Z.; Karpinski, J.

    2015-02-01

    A review of the magnetism in the parent compounds of the iron-based superconductors is given based on the transmission Mössbauer spectroscopy of 57Fe and 151Eu. It was found that the 3d magnetism is of the itinerant character with varying admixture of the spin-polarized covalent bonds. For the '122' compounds, a longitudinal spin density wave (SDW) develops. In the case of the EuFe2As2, a divalent europium arranges in an anti-ferromagnetical order at a much lower temperature as compared with the onset of SDW. These two magnetic systems remain almost uncoupled one to another. For the non-stoichiometric Fe1+xTe parent of the '11' family, one has a transversal SDW and magnetic order of the interstitial iron with relatively high and localized magnetic moments. These two systems are strongly coupled one to another. For the 'grand parent' of the iron-based superconductors FeAs, one observes two mutually orthogonal phase-related transversal SDW on the iron sites. There are two sets of such spin arrangements due to two crystallographic iron sites. The FeAs exhibits the highest covalency among the compounds studied, but it has still a metallic character. A contribution to XVI National Conference on Superconductivity, Zakopane, Poland, 7-12 October 2013.

  8. Producing Ceramic High Tc Superconductors for Strong Current Applications

    Institute of Scientific and Technical Information of China (English)

    Jian-Xun Jin; Yuan-Chang Guo; Xue-Kei Fu; Shi-Xue Dou

    2000-01-01

    @@ Strong current and large-scale application is the most important prospect of high Tc superconductors (HTS).Practical HTS samples, both in forms of wire and bulk, have been produced with high critical currents operated at economic cryogenic temperatures, and studied for engineering applications with various prototype devices. The applicable HTS materials produced are introduced in this paper with regard to processing, characterization and application.

  9. Cryocooler applications for high-temperature superconductor magnetic bearings.

    Energy Technology Data Exchange (ETDEWEB)

    Niemann, R. C.

    1998-05-22

    The efficiency and stability of rotational magnetic suspension systems are enhanced by the use of high-temperature superconductor (HTS) magnetic bearings. Fundamental aspects of the HTS magnetic bearings and rotational magnetic suspension are presented. HTS cooling can be by liquid cryogen bath immersion or by direct conduction, and thus there are various applications and integration issues for cryocoolers. Among the numerous cryocooler aspects to be considered are installation; operating temperature; losses; and vacuum pumping.

  10. Influence of Proton Irradiation on Angular Dependence of Second Generation (2G)HTS

    Energy Technology Data Exchange (ETDEWEB)

    Shiroyanagi, Y.; Greene, G.; Gupta, R.; Sampson, W.

    2011-05-01

    In the Facility for Rare Isotope Beams (FRIB) the quadrupoles in the fragment separator are exposed to very high radiation and heat loads. High Temperature Superconductors (HTS) are a good candidate for these magnets because they can be used at {approx}30-50 K and tolerate higher heat generation than Nb-Ti magnets. Radiation damage studies of HTS wires are crucial to ensure that they will survive in a high radiation environment. HTS wires from two vendors were studied. Samples of 2G HTS wires from SuperPower and American Superconductor (ASC) were irradiated with a 42 {mu}A, 142 MeV proton beam from the Brookhaven Linac Isotope Producer (BLIP). The angular dependence of the critical current was measured in magnetic fields at 77K.

  11. The effect of temperature on pinning mechanisms in HTS composites

    Science.gov (United States)

    Sotnikova, A. P.; Rudnev, I. A.

    2016-09-01

    Pinning mechanism in samples of second generation tapes (2G) of high-temperature superconductors (HTS) was studied The critical current and the pinning force were calculated from the magnetization curves measured in the temperature range of 4.2 - 77 K in magnetic fields up to 14 Tesla using vibration sample magnetometer. To determine the pinning mechanism the dependences of pinning force on magnetic field were constructed according to the Dew-Hughes model and Kramer's rule. The obtained dependences revealed a significant influence of the temperature on effectiveness of different types of pinning. At low temperatures the 2G HTS tapes of different manufacturers demonstrated an equal efficiency of the pinning centers but with temperature increase the differences in pinning mechanisms as well as in properties and effectiveness of the pinning centers become obvious. The influence of the pinning mechanism on the energy losses in HTS tapes was shown.

  12. Application of HTS technology to cardiac dysrhythmia detection

    Energy Technology Data Exchange (ETDEWEB)

    Sobel, A.L. [Sandia National Labs., Albuquerque, NM (United States); Avrin, W.F. [Quantum Magnetics, Inc., San Diego, CA (United States)

    1994-12-01

    This paper discusses the conceptual design considerations and challenges for development of a contactless, mobile, single channel biomagnetic sensor system based on High-Temperature Superconductor (HTS) Superconducting Quantum Interference Devices (SQUIDs) and employing the Three-SQUID Gradiometer (TSG) concept. Operating in magnetically unshielded environments, as are encountered in many medical scenarios, this instrument class would monitor cardiac electrical activity with minimal patient preparation and intrusiveness, and would notionally be coupled with a clinically adaptive human-system interface (HSI).

  13. LabVIEW and PCI DAQ Card Based HTS Test and Control Platforms

    Institute of Scientific and Technical Information of China (English)

    Hui-Bin Zhao; Jian-Xun Jin; Pu-Chun Jiang; Wen-Hui Gao; Zi-Lu Liang

    2008-01-01

    This paper introduces the relevant parameters and related characteristics of the LabVIEW and PCI6221 data acquisition (DAQ) card, describes in detail the approach of building the measure and control platform of virtual instrument (VI) using LabVIEW and PCI6221, specifically discusses the system's application in high temperature superconductor (HTS) research including the test of HTS volt-ampere characteristics and the HTS magnetic energy storage. The experiments prove that the VI test and control system is easy to build and convenient to use.

  14. Design, Construction and Test of Cryogen-Free HTS Coil Structure

    Energy Technology Data Exchange (ETDEWEB)

    Hocker, H.; Anerella, M.; Gupta, R.; Plate, S.; Sampson, W.; Schmalzle, J.; Shiroyanagi, Y.

    2011-03-28

    This paper will describe design, construction and test results of a cryo-mechanical structure to study coils made with the second generation High Temperature Superconductor (HTS) for the Facility for Rare Isotope Beams (FRIB). A magnet comprised of HTS coils mounted in a vacuum vessel and conduction-cooled with Gifford-McMahon cycle cryocoolers is used to develop and refine design and construction techniques. The study of these techniques and their effect on operations provides a better understanding of the use of cryogen free magnets in future accelerator projects. A cryogen-free, superconducting HTS magnet possesses certain operational advantages over cryogenically cooled, low temperature superconducting magnets.

  15. Design Construction and Test Results of a HTS Solenoid For Energy Recovery Linac

    Energy Technology Data Exchange (ETDEWEB)

    Anerella, M; Ben-Zvi, I; Kayran, D; McIntyre, G; Muratore, J; Plate, S; Sampson, W; Cole, M

    2011-03-28

    An innovative feature of the proposed Energy Recovery Linac (ERL) is the use of a solenoid made with High Temperature Superconductor (HTS) with the Superconducting RF cavity. The use of HTS allows solenoid to be placed in close proximity to the cavity and thus provides early focusing of the electron beam. In addition, cryogenic testing at {approx}77 K is simpler and cheaper than 4 K testing. This paper will present the design, construction and test results of this HTS solenoid. The HTS solenoid in the proposed ERL will be situated in the transition region between the superconducting cavity at {approx}4 K and the cryostat at the room temperature. Solenoid inside the cryogenic structure provides an early focusing and hence low emittance beam. The temperature in the transition region will be too high for a conventional low temperature superconductor and resistive heat load from copper coils will be too high on cryogenic system. HTS coils also allow much higher current density and significant reduction in size as compared to copper coils. Hence HTS solenoid provide a unique and technically superior solution. The use of a HTS solenoid with superconducting cavity offers a unique option as it can be placed in a cold to warm transition region to provide early focussing without using additional space. Construction and test results so far are very encouraging for its use in the ERL project.

  16. Electronic structure studies of ferro-pnictide superconductors and their parent compounds using angle-resolved photoemission spectroscopy (ARPES)

    Energy Technology Data Exchange (ETDEWEB)

    Setti, Thirupathaiah

    2011-07-14

    The discovery of high temperature superconductivity in the iron pnictide compound LaO{sub 1-x}F{sub x}FeAs with T{sub c} = 26 K as created enormous interest in the high-T{sub c} superconductor community. So far, four prototypes of crystal structures have been found in the Fe-pnictide family. All four show a structural deformation followed or accompanied by a magnetic transition from a high temperature paramagnetic conductor to a low temperature antiferromagnetic metal whose transition temperature T{sub N} varies between the compounds. Charge carrier doping, isovalent substitution of the As atoms or the application of pressure suppresses the antiferromagnetic spin density wave (SDW) order and leads to a superconducting phase. More recently high Tc superconductivity has been also detected in iron chalchogenides with similar normal state properties. Since superconductivity is instability of the normal state, the study of normal state electronic structure in comparison with superconducting state could reveal important information on the pairing mechanism. Therefore, it is most important to study the electronic structure of these new superconductors, i.e., to determine Fermi surfaces and band dispersions near the Fermi level at the high symmetry points in order to obtain a microscopic understanding of the superconducting properties. Using the technique angle-resolved photoemission spectroscopy (ARPES) one measures the electrons ejected from a sample when photons impinge on it. In this way one can map the Fermi surface which provides useful information regarding the physics behind the Fermi surface topology of high T{sub c} superconductors. Furthermore, this technique provides information on the band dispersion, the orbital character of the bands, the effective mass, the coupling to bosonic excitations, and the superconducting gap. This emphasizes the importance of studying the electronic structure of the newly discovered Fe-pnictides using ARPES. In this work we have

  17. High temperature superconductors for magnetic suspension applications

    Science.gov (United States)

    Mcmichael, C. K.; Cooley, R. S.; Chen, Q. Y.; Ma, K. B.; Lamb, M. A.; Meng, R. L.; Chu, C. W.; Chu, W. K.

    1994-01-01

    High temperature superconductors (HTS) hold the promise for applications in magnetic levitation bearings, vibration damping, and torque coupling. Traditional magnetic suspension systems require active feedback and vibration controls in which power consumption and low frequency vibration are among the major engineering concerns. HTS materials have been demonstrated to be an enabling approach towards such problems due to their flux trapping properties. In our laboratory at TCSUH, we have been conducting a series of experiments to explore various mechanical applications using HTS. We have constructed a 30 lb. model flywheel levitated by a hybrid superconducting magnetic bearing (HSMB). We are also developing a levitated and vibration-dampled platform for high precision instrumentation. These applications would be ideal for space usages where ambient temperature is adequate for HTS to operate properly under greatly reduced cryogenic requirements. We will give a general overview of these potential applications and discuss the operating principles of the HTS devices we have developed.

  18. Understanding and eliminating the fast creep problem in Fe-based superconductors

    Science.gov (United States)

    Civale, Leonardo; Eley, Serena; Maiorov, Boris; Miura, Masashi

    One surprising characteristic of Fe-based superconductors is that they exhibit flux creep rates (S) as large as, or larger than, those found in oxide high temperature superconductors (HTS). This very fast vortex dynamics appears to be inconsistent with the estimate of the influence of the thermal fluctuations as quantified by the Ginzburg number (Gi), which measures the ratio of the thermal energy to the condensation energy in an elemental superconducting volume. In particular, compounds of the AFe2As2 family (``122'') have Gi ~10-5 to 10-4, so S could be expected to lie between that of low Tc materials (where typically Gi ~ 10-8) and HTS such as YBa2Cu3O7 (Gi ~ 10-2) , as indeed occurs in other superconductors with intermediate fluctuations, such as MgB2 (Gi ~10-6 to 10-4) . We have found the solution to this puzzle: the fast creep rates in 122 compounds are due to non-optimized pinning landscapes. Initial evidence comes from our previous studies showing that the introduction of additional disorder by irradiation decreases creep significantly in 122 single crystals, although still remaining well above the ideal limit. We now have new evidence from 122 thin films demonstrating that S can be reduced to the lower limit set by Gi by appropriate engineering of the pinning landscape.

  19. The magnetostriction in a superconductor-magnet system under non-uniform magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xueyi; Jiang, Lang; Wu, Hao [Key Laboratory of Mechanics on Disaster and Environment in Western China attached to the Ministry of Education of China, Lanzhou University, Lanzhou, Gansu 730000 (China); Gao, Zhiwen, E-mail: gaozhw@lzu.edu.cn [Department of Mechanics and Engineering Science, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China)

    2017-03-15

    Highlights: • We studied firstly magnetostriction in HTS under non-uniform magnetic field. • The superconductors may be homogeneous and nonhomogeneous. • The magnetostrictions response of the HTS is sensitive to the critical current density and amplitude of the applied magnetic field. • The magnetostriction of nonhomogeneous HTS is larger than that of homogeneous HTS. - Abstract: This paper describes a numerical model to examine the magnetostriction of bulk high-temperature superconductor (HTS) under non-uniform magnetic field in conjunction with finite element analysis. Through this model, the magnetostriction of homogeneous and nonhomogeneous HTS can be implemented under non-uniform magnetic field. Further, the effects of critical current density, applied field frequency and amplitude are also considered. The computational study can provide a fundamental mechanistic understanding the effects of non-uniform magnetic field on magnetostriction of HTS.

  20. Comparison between HTS nonlinearities in patterned and unpatterned thin films

    Science.gov (United States)

    Mateu, Jordi; Collado, Carlos; O'Callaghan, Juan M.; Universitat Politecnica de Catalunya Team

    2004-03-01

    High Temperature Superconductor (HTS) materials exhibit a surface impedance dependence on the applied field. This behavior still remains not yet fully understood. To overcome this, many experiments have been carried out through the last decade. In general, the experimental work has been done measuring intermodulation products in patterned devices since most of practical devices are based on patterned structures. In this case the nonlinearities might come from many causes -- HTS properties, possible damage due to patterning, shape of resonator, etc.--, which need to be characterized. This raises the question of how representative of HTS properties are the experiments performed on patterned samples. To address this, we propose such a procedure, which is based on obtaining parameters describing the HTS nonlinearities from intermodulation measurements made on unpatterned and patterned thin films. As example, we have characterized the nonlinearities in a one side 10x10 mm^2 YBCO on MgO thin film by measuring the intermodulation products with a rutile-loaded cavity operating at TE_011 mode and a coplanar half-wave resonator. The intermodulation data in both type of measurements can be fitted using closed-form expressions and numerical techniques with identical nonlinear parameters of the HTS.

  1. Fracton pairing mechanism for unconventional superconductors: Self-assembling organic polymers and copper-oxide compounds

    DEFF Research Database (Denmark)

    Milovanov, A.V.; Juul Rasmussen, J.

    2002-01-01

    or holes) exchange fracton excitations, quantum oscillations of fractal lattices that mimic the complex microscopic organization of the unconventional superconductors. For the copper oxides, the superconducting transition temperature T-c as predicted by the fracton mechanism is of the order of similar to...... description of the complex fractal sets underlying the fracton spectrum. A generalized kinetic equation containing integer time and fractional real-space derivatives is found for the fracton excitations in the harmonic approximation. The fracton superconductivity mechanism is further discussed in connection...

  2. The thickness optimization of the magnet and superconductor in HTS maglev system%单块磁悬浮系统磁体和超导体的厚度优化

    Institute of Scientific and Technical Information of China (English)

    付志方; 赵立峰; 马家庆; 张勇; 赵勇

    2013-01-01

    The effect of thickness of magnets and YBCO superconductor bulks on suspended force was studied in this paper. Levitation forces of superconductor bulks with different thickness above magnets of φ>30mm × 18mm and φ30mm × 10mm were examined , respectively. The optimal values of the thickness of the magnet and superconductor bulks were thus obtained. Furthermore , vibration responses of the levitation systems mentioned above were also studied, and the best combination of magnet and superconductor bulk was obtained according to spectrum analysis.%研究了磁铁厚度和YBCO超导体厚度对悬浮力的大小及系统动态特性的影响,通过分析得出磁悬浮系统中磁体和超导体厚度的最优值.通过悬浮力测试系统测得超导块尺寸为φ30mm×18mm时四块不同厚度的磁体的悬浮力以及磁体尺寸为φ30mm × 10mm时六块不同厚度的YBCO超导体的悬浮力的大小;并在振动实验台上测试了上述情况下的振动特性.对动态曲线进行频谱分析,最终得出最优组合,从而对磁悬浮系统的磁体和超导体厚度进行了优化.

  3. Momentum-Resolved Electronic Structure of the High-T_{c} Superconductor Parent Compound BaBiO_{3}.

    Science.gov (United States)

    Plumb, N C; Gawryluk, D J; Wang, Y; Ristić, Z; Park, J; Lv, B Q; Wang, Z; Matt, C E; Xu, N; Shang, T; Conder, K; Mesot, J; Johnston, S; Shi, M; Radović, M

    2016-07-15

    We investigate the band structure of BaBiO_{3}, an insulating parent compound of doped high-T_{c} superconductors, using in situ angle-resolved photoemission spectroscopy on thin films. The data compare favorably overall with density functional theory calculations within the local density approximation, demonstrating that electron correlations are weak. The bands exhibit Brillouin zone folding consistent with known BiO_{6} breathing distortions. Though the distortions are often thought to coincide with Bi^{3+}/Bi^{5+} charge ordering, core level spectra show that bismuth is monovalent. We further demonstrate that the bands closest to the Fermi level are primarily oxygen derived, while the bismuth 6s states mostly contribute to dispersive bands at deeper binding energy. The results support a model of Bi-O charge transfer in which hole pairs are localized on combinations of the O 2p orbitals.

  4. EXAFS Studies of (Pb,Cd) 1212 phase superconductor and (Bi,Cd)1212 phase compound

    Institute of Scientific and Technical Information of China (English)

    YeTao; ShiqiangWei; 等

    1999-01-01

    We synthesized (Pb,Cd)Sr2(Y,Ca)Cu2O7+x,phase superconductor.After substitution of Pb with Bi,the BiCd1212 phase shows no superconductivity.Although previous EXAFS study has shown the local structure environment of the Cu is similar in both compounds,EXAFS results of Bi and Pb here demonstrate that σ2 of Pb-Oin-plane is larger than that of Bi-O inplane,whereas σ2 of Pb-Oapical is smaller than that of Bi-O,wherase σ2 of Pb-O apical is smaller than that of Bi-Oapical.The Sr shell features are also differnet,it appeared that superconductivity needs some disorder .in carrier reservoir layer,which is due to the substitutional defect caused by different ionic radii.

  5. Design and Development of a 100 MVA HTS Generator for Commercial Entry

    Energy Technology Data Exchange (ETDEWEB)

    None

    2007-06-07

    In 2002, General Electric and the US Department of Energy (DOE) entered into a cooperative agreement for the development of a commercialized 100 MVA generator using high temperature superconductors (HTS) in the field winding. The intent of the program was to: (1) identify and develop technologies that would be needed for such a generator; (2) develop conceptual designs for generators with ratings of 100 MVA and higher using HTS technology; (3) perform proof of concept tests at the 1.5 MW level for GE's proprietary warm iron rotor HTS generator concept; and (4) design, build, and test a prototype of a commercially viable 100 MVA generator that could be placed on the power grid. This report summarizes work performed during the program and is provided as one of the final program deliverables. The design for the HTS generator was based on GE's warm iron rotor concept in which a cold HTS coil is wound around a warm magnetic iron pole. This approach for rotating HTS electrical machinery provides the efficiency benefits of the HTS technology while addressing the two most important considerations for power generators in utility applications: cost and reliability. The warm iron rotor concept uses the least amount of expensive HTS wire compared to competing concepts and builds on the very high reliability of conventional iron core stators and armature windings.

  6. Coil Optimization for HTS Machines

    DEFF Research Database (Denmark)

    Mijatovic, Nenad; Jensen, Bogi Bech; Abrahamsen, Asger Bech

    for different tape parameters Ici, ni and Ci, where Ici, ni and Ci are critical current, n - value and price of the ith tape respectively and i=1, 2, 3…, further optimization with respect to cost vs. HTS losses has been performed. Allowing for different types of HTS tapes in the coils, a guidance to which tape....... The proposed coil design is optimized with respect to minimizing the perpendicular field while still maximizing the amplitude of fundamental space harmonic. This guarantees the lowest HTS loss density and best utilization of expensive HTS material in the field winding of the SM. Additionally, accounting...

  7. Mechanism of thickness dependence of critical current density in HTS YBCO film and its elimination using nano-engineering

    Science.gov (United States)

    Wang, Xiang

    The most promising characteristic of a High Temperature Superconductor (HTS) is its ability to carry larger electrical current at liquid nitrogen boiling temperature and strong applied magnetic field with minimal dissipation. Numerous large scale applications such as HTS transmission cables, HTS magnets and HTS motors have been developed using HTS materials. The major limitation that prevents its wide commercialization is its high cost-to-performance ratio. However, the effort to further improve HTS current carrying capability is jeopardized by a mysterious thickness dependence of the critical current density (Jc) --- Jc monotonically decreases with increasing thickness (t) at 77 K and self-field (SF). This poses a great challenge for both HTS applications and the understanding of vortex dynamics. What further complicates this issue is the complex defect structure in HTS films as well as the creep nature of magnetic vortices at a finite temperature. After a systematic study of the temperature and magnetic field effects on Jc--t, we conclude that Jc--t is most likely the result of a collective pinning effect dictated by a random pinning potential. Besides that, thermal fluctuations also alter Jc--t in a predictable way. Therefore, by either modifying the vortex structure or pinning structure, J c--t can be eliminated. Indeed, a thin film J c has been restored in a HTS/insulator/HTS trilayer while the magnetic coupling is weakened. Moreover, Jc--t has been removed when the random distributed point pins are overpowered by strong linear defects.

  8. Scaling rules for critical current density in anisotropic biaxial superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yingxu, E-mail: yingxuli@swjtu.edu.cn [Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province, School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Kang, Guozheng [Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province, School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Gao, Yuanwen, E-mail: ywgao@lzu.edu.cn [Key Laboratory of Mechanics on Environment and Disaster in Western China, The Ministry of Education of China, Lanzhou, Gansu 730000 (China); Department of Mechanics and Engineering Science, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China)

    2016-06-15

    Recent researches highlight the additional anisotropic crystallographic axis within the superconducting plane of high temperature superconductors (HTS), demonstrating the superconducting anisotropy of HTS is better understood in the biaxial frame than the previous uniaxial coordinates within the superconducting layer. To quantitatively evaluate the anisotropy of flux pinning and critical current density in HTS, we extend the scaling rule for single-vortex collective pinning in uniaxial superconductors to account for flux-bundle collective pinning in biaxial superconductors. The scaling results show that in a system of random uncorrected point defects, the field dependence of the critical current density is described by a unified function with the scaled magnetic field of the isotropic superconductor. The obtained angular dependence of the critical current density depicts the main features of experimental observations, considering possible corrections due to the strong-pinning interaction.

  9. Armature reaction effects on HTS field winding in HTS machine

    DEFF Research Database (Denmark)

    Mijatovic, Nenad; Jensen, Bogi Bech

    2013-01-01

    This paper presents experimental results from the Superwind laboratory setup. Particular focus in the paper has been placed on describing and quantifying the in influence of armature reaction on performance of the HTS fled winding. Presented experimental results have confrmed the HTS feld winding...

  10. Some potential antenna applications of high-temperature superconductors

    Science.gov (United States)

    Dinger, Robert J.

    1990-09-01

    A review of possible applications of high temperature superconductors (HTS) to antennas and antenna feed networks is presented. The frequency range of consideration is 1 MHz to 100 GHz. Three antenna application areas seem appropriate for HTS material. (1) Electrically small antennas and their matching networks: an increase in efficiency is possible for electrically short antennas, but at the expense of bandwidth. Substantial radiated power levels (on the order of kilowatts) can be handled by the best HTS material. Substantial improvement may be realized by making only the matching network of HTS material. (2) Feed and matching networks for compact arrays with enhanced directive gain (superdirective arrays): HTS material should permit such arrays to be fabricated that have high efficiency. (3) Feed networks for millimeter-wave arrays: Low-loss feed networks using HTS microstrip transmission lines give many decibels improvement in gain.

  11. Chemical stability of high-temperature superconductors

    Science.gov (United States)

    Bansal, Narottam P.

    1992-01-01

    A review of the available studies on the chemical stability of the high temperature superconductors (HTS) in various environments was made. The La(1.8)Ba(0.2)CuO4 HTS is unstable in the presence of H2O, CO2, and CO. The YBa2Cu3O(7-x) superconductor is highly susceptible to degradation in different environments, especially water. The La(2-x)Ba(x)CuO4 and Bi-Sr-Ca-Cu-O HTS are relatively less reactive than the YBa2Cu3O(7-x). Processing of YBa2Cu3O(7-x) HTS in purified oxygen, rather than in air, using high purity noncarbon containing starting materials is recommended. Exposure of this HTS to the ambient atmosphere should also be avoided at all stages during processing and storage. Devices and components made out of these oxide superconductors would have to be protected with an impermeable coating of a polymer, glass, or metal to avoid deterioration during use.

  12. Low resistance splices for HTS devices and applications

    Science.gov (United States)

    Lalitha, S. L.

    2017-09-01

    This paper discusses the preparation methodology and performance evaluation of low resistance splices made of the second generation (2G) high-temperature superconductor (HTS). These splices are required in a broad spectrum of HTS devices including a large aperture, high-field solenoid built in the laboratory to demonstrate a superconducting magnetic energy storage (SMES) device. Several pancake coils are assembled in the form of a nested solenoid, and each coil requires a hundred meters or more of 2G (RE)BCO tape. However, commercial availability of this superconductor with a very uniform physical properties is currently limited to shorter piece lengths. This necessitates us having splices to inter-connect the tape pieces within a pancake coil, between adjacent pancake coils, and to attach HTS current leads to the magnet assembly. As a part of the optimization and qualification of splicing process, a systematic study was undertaken to analyze the electrical performance of splices in two different configurations suitable for this magnet assembly: lap joint and spiral joint. The electrical performance is quantified in terms of the resistance of splices estimated from the current-voltage characteristics. It has been demonstrated that a careful application of this splicing technique can generate lap joints with resistance less than 1 nΩ at 77 K.

  13. Negative magnetic relaxation in superconductors

    Directory of Open Access Journals (Sweden)

    Krasnoperov E.P.

    2013-01-01

    Full Text Available It was observed that the trapped magnetic moment of HTS tablets or annuli increases in time (negative relaxation if they are not completely magnetized by a pulsed magnetic field. It is shown, in the framework of the Bean critical-state model, that the radial temperature gradient appearing in tablets or annuli during a pulsed field magnetization can explain the negative magnetic relaxation in the superconductor.

  14. Losses of Superconductor Journal Bearing

    Science.gov (United States)

    Han, Y. H.; Hull, J. R.; Han, S. C.; Jeong, N. H.; Oh, J. M.; Sung, T. H.

    2004-06-01

    A high-temperature superconductor (HTS) journal bearing was studied for rotational loss. Two HTS bearings support the rotor at top and bottom. The rotor weight is 4 kg and the length is about 300 mm. Both the top and bottom bearings have two permanent magnet (PM) rings with an iron pole piece separating them. Each HTS journal bearing is composed of six pieces of superconductor blocks of size 35×25×10 mm. The HTS blocks are encased in a cryochamber through which liquid nitrogen flows. The inner spool of the cryochamber is made from G-10 to reduce eddy current loss, and the rest of the cryochamber is stainless steel. The magnetic field from the PM rings is < 10 mT on the stainless part. The rotational drag was measured over the same speed range at several chamber pressures. Results indicate that a chamber pressure of 0.4 mtorr is sufficiently low to minimize windage loss, and the 10 mT design criterion for the magnetic field on the stainless part of the cryochamber is too high.

  15. Superconductor bearings, flywheels and transportation

    Science.gov (United States)

    Werfel, F. N.; Floegel-Delor, U.; Rothfeld, R.; Riedel, T.; Goebel, B.; Wippich, D.; Schirrmeister, P.

    2012-01-01

    This paper describes the present status of high temperature superconductors (HTS) and of bulk superconducting magnet devices, their use in bearings, in flywheel energy storage systems (FESS) and linear transport magnetic levitation (Maglev) systems. We report and review the concepts of multi-seeded REBCO bulk superconductor fabrication. The multi-grain bulks increase the averaged trapped magnetic flux density up to 40% compared to single-grain assembly in large-scale applications. HTS magnetic bearings with permanent magnet (PM) excitation were studied and scaled up to maximum forces of 10 kN axially and 4.5 kN radially. We examine the technology of the high-gradient magnetic bearing concept and verify it experimentally. A large HTS bearing is tested for stabilizing a 600 kg rotor of a 5 kWh/250 kW flywheel system. The flywheel rotor tests show the requirement for additional damping. Our compact flywheel system is compared with similar HTS-FESS projects. A small-scale compact YBCO bearing with in situ Stirling cryocooler is constructed and investigated for mobile applications. Next we show a successfully developed modular linear Maglev system for magnetic train operation. Each module levitates 0.25t at 10 mm distance during one-day operation without refilling LN2. More than 30 vacuum cryostats containing multi-seeded YBCO blocks are fabricated and are tested now in Germany, China and Brazil.

  16. Signatures of granular superconductivity and Josephson effects in macroscopic measurements: the case of new superconductors

    Directory of Open Access Journals (Sweden)

    S Senoussi

    2006-09-01

    Full Text Available   We report systematic investigations of the magnetic superconducting properties of the new superconducting materials (NS: New high temperature superconductors (HTS, Organic superconductors (OS, fullerenes, carbon nanotubes, MgB2 etc. We show that, contrary to conventional superconductors where the superconducting state can be coherent over several tenths of km, the macroscopic coherence range lc of the NS is often as short as 0.1 to 10 µm typically. As a consequence, the magnetic properties are dominated by granular-like effects as well as Josephson coupling between grains. Here, we concentrate on HTS ceramics and organic superconductors exclusively. In the first case we observe three distinct regimes: (i At very low field (H < 5 Oe to say all the grains are coupled via Josephson effect and lc can be considered as infinite. (2 At intermediate field (5 < H < 50 Oe, typically the grains are gradually decoupled by H and/or T. (iii At higher fields all the grains are decoupled and lc roughly coincides with the diameter of the metallurgical grains. The case of OS is more subtle and is connected with a kind of order-disorder transition that occurs in most of them. For instance, in this study, we exploit quenched disorder (after crossing such a transition in the -(BEDT-TTF2Cu[N(CN2]Br layered organic superconductor to get new insights on both the superconducting state (T £ 11.6 K and the glassy transition at Tg, by studying the superconducting properties as functions of annealing time and annealing temperature around the glassy transition. Our main result is that the data can be described by a percolation molecular cluster model in which the topology and the growth of the molecular clusters obey an Ising spin-glass-like model with Tg ≈ 80 K for the hydrogenated compound and Tg ≈ 55 K for the fully deuterated one.

  17. Statistical correlations for thermophysical properties of Supercritical Argon (SCAR) used in cooling of futuristic High Temperature Superconducting (HTS) cables

    Energy Technology Data Exchange (ETDEWEB)

    Kalsia, Mohit [School of Mechanical Engineering, Lovely Professional University, Phagwara, 144 401 (India); Dondapati, Raja Sekhar, E-mail: drsekhar@ieee.org [School of Mechanical Engineering, Lovely Professional University, Phagwara, 144 401 (India); Usurumarti, Preeti Rao [Department of Mechanical Engineering, PVK Institute of Technology, Anantpur, 515 001 (India)

    2017-05-15

    Highlights: • The developed correlations can be integrated into thermohydraulic analysis of HTS cables. • This work also explains the phenomenon of flow with less pumping power and maximum heat transfer in HTS cables. • Pumping power required to circulate the SCAR for cooling of HTS cables would be significantly lower. • For Hg-based high temperature superconductors (T{sub c} > 134 K), SCAR found to be a suitable coolant. - Abstract: High Temperature Superconducting (HTS) cables are emerging as an alternative to conventional cables in efficient power transmission. However, these HTS cables require cooling below the critical temperature of superconductors used to transmit larger currents. With the invention of high temperature superconductors whose critical temperatures are up to 134 K (Hg based), it is a great challenge to identify a suitable coolant which can carry away the heating load on the superconductors. In order to accomplish such challenge, an attempt has been made in the present work to propose supercritical Argon (SCAR) as the alternative to cool the HTS cables. Further, a statistical correlation has been developed for the thermophysical properties such as density, viscosity, specific heat and thermal conductivity of SCAR. In addition, the accuracy of developed correlations is established with the help of few statistical parameters and validated with standard database available in the literature. These temperature dependent accurate correlations are useful in predicting the pressure drop and heat transfer behaviour in HTS cables using numerical or computational techniques. In recent times, with the sophistication of computer technology, solving of various complex transport equations along with the turbulence models became popular and hence the developed correlations would benefit the technological community. It is observed that, a decrease in pressure, density and viscosity are found to be decreasing whereas the thermal conductivity and specific

  18. Test Results of HTS Coil and Magnet R&D for RIA

    CERN Document Server

    Gupta, Ramesh C; Harrison, Michael; Sampson, William; Schmalzle, Jesse D; Zeller, Al

    2005-01-01

    Brookhaven National Laboratory is developing quadrupole magnets for the proposed Rare Isotope Accelerator (RIA) based on commercially available High Temperature Superconductors (HTS). These quadrupoles will be used in the Fragment Separator region and are one of the more challenging elements in the RIA proposal. They will be subjected to several orders of magnitude more energy and radiation deposition than typical beam line and accelerator magnets receive during their entire lifetime. The proposed quadrupoles will operate in the 20-40 K temperature range for efficient heat removal. HTS coils that have been tested so far indicate that the coils meet the magnetic field requirements of the design. We will report the test results of about 10 HTS coils and of a magnetic mirror configuration that simulates the magnetic field and Lorentz force in the proposed quadrupole. In addition, the preliminary design of an HTS dipole magnet for the Fragment Separator region will also be presented.

  19. Correlations Between Magnetic Flux and Levitation Force of HTS Bulk Above a Permanent Magnet Guideway

    Science.gov (United States)

    Huang, Huan; Zheng, Jun; Zheng, Botian; Qian, Nan; Li, Haitao; Li, Jipeng; Deng, Zigang

    2017-06-01

    In order to clarify the correlations between magnetic flux and levitation force of the high-temperature superconducting (HTS) bulk, we measured the magnetic flux density on bottom and top surfaces of a bulk superconductor while vertically moving above a permanent magnet guideway (PMG). The levitation force of the bulk superconductor was measured simultaneously. In this study, the HTS bulk was moved down and up for three times between field-cooling position and working position above the PMG, followed by a relaxation measurement of 300 s at the minimum height position. During the whole processes, the magnetic flux density and levitation force of the bulk superconductor were recorded and collected by a multipoint magnetic field measurement platform and a self-developed maglev measurement system, respectively. The magnetic flux density on the bottom surface reflected the induced field in the superconductor bulk, while on the top, it reveals the penetrated magnetic flux. The results show that the magnetic flux density and levitation force of the bulk superconductor are in direct correlation from the viewpoint of inner supercurrent. In general, this work is instructive for understanding the connection of the magnetic flux density, the inner current density and the levitation behavior of HTS bulk employed in a maglev system. Meanwhile, this magnetic flux density measurement method has enriched present experimental evaluation methods of maglev system.

  20. Influence analysis of structural parameters and operating parameters on electromagnetic properties of HTS linear induction motor

    Science.gov (United States)

    Fang, J.; Sheng, L.; Li, D.; Zhao, J.; Li, Sh.; Qin, W.; Fan, Y.; Zheng, Q. L.; Zhang, W.

    A novel High Temperature Superconductor Linear Induction Motor (HTS LIM) is researched in this paper. Since the critical current and the electromagnetic force of the motor are determined mainly by the primary slot leakage flux, the main magnetic flux and eddy current respectively, in order to research the influence of structural parameters and operating parameters on electromagnetic properties of HTS LIM, the motor was analyzed by 2D transient Finite Element Method (FEM). The properties of the motor, such as the maximum slot leakage flux density, motor thrust, motor vertical force and critical current are analyzed with different structural parameters and operating parameters. In addition, an experimental investigation was carried out on prototype HTS motor. Electrical parameters were deduced from these tests and also compared with the analysis results from FEM. AC losses of one HTS coil in the motor were measured and AC losses of all HTS coils in HTS LIM were estimated. The results in this paper could provide reference for the design and research on the HTS LIM.

  1. Unusual electronic structure and observation of dispersion kink in CeFeAsO parent compound of FeAs-based superconductors.

    Science.gov (United States)

    Liu, Haiyun; Chen, G F; Zhang, Wentao; Zhao, Lin; Liu, Guodong; Xia, T-L; Jia, Xiaowen; Mu, Daixiang; Liu, Shanyu; He, Shaolong; Peng, Yingying; He, Junfeng; Chen, Zhaoyu; Dong, Xiaoli; Zhang, Jun; Wang, Guiling; Zhu, Yong; Xu, Zuyan; Chen, Chuangtian; Zhou, X J

    2010-07-01

    We report the first comprehensive high-resolution angle-resolved photoemission measurements on CeFeAsO, a parent compound of FeAs-based high temperature superconductors with a magnetic-structural transition at ∼150 K. In the magnetic-ordering state, four holelike Fermi surface sheets are observed near Γ(0,0), and the Fermi surface near M(±π,±π) shows a tiny electronlike pocket at M surrounded by four strong spots. The unusual Fermi surface topology deviates strongly from the band structure calculations. The electronic signature of the magnetic-structural transition shows up in the dramatic change of the quasiparticle scattering rate. A dispersion kink at ∼25 meV is observed for the first time in the parent compound of Fe-based superconductors.

  2. Temperature dependence of levitation force and its relaxation in a HTS levitation system

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Jun; Zhang Xingyi [Key Laboratory of Mechanics on Western Disaster and Environment, Department of Mechanics and Engineering Science, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China); Zhou Youhe, E-mail: zhouyh@lzu.edu.c [Key Laboratory of Mechanics on Western Disaster and Environment, Department of Mechanics and Engineering Science, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China)

    2010-03-01

    Using a modified Gifford-McMahon refrigerator to cool the cylindrical bulk YBaCuO superconductor within the region of 100-10 K, and using an updated high-temperature superconductor (HTS) maglev measurement system, the levitation force and its time relaxation at different temperatures between a YBaCuO bulk superconductor and a permanent magnet (PM) have been measured under zero-field cooling. It is found that decrease the cooling temperature of HTS can decrease the hysteresis of magnetization and increase the maximum levitation force of each hysteresis loop. For the relaxation of levitation force, if the temperature is continually lowered to 10 K after the relaxation measurement at given cooling temperature is performed for 600 s, the levitation force will continue to decrease sharply with the lowering of temperature even though it will get stable if the temperature is not lowered. Our results shown in this work are a benefit to the understanding of levitation systems.

  3. Gravimeter using high-temperature superconductor bearing.

    Energy Technology Data Exchange (ETDEWEB)

    Hull, J. R.

    1998-09-11

    We have developed a sensitive gravimeter concept that uses an extremely low-friction bearing based on a permanent magnet (PM) levitated over a high-temperature superconductor (HTS). A mass is attached to the PM by means of a cantilevered beam, and the combination of PM and HTS forms a bearing platform that has low resistance to rotational motion but high resistance to horizontal, vertical, or tilting motion. The combination acts as a low-loss torsional pendulum that can be operated in any orientation. Gravity acts on the cantilevered beam and attached mass, accelerating them. Variations in gravity can be detected by time-of-flight acceleration, or by a control coil or electrode that would keep the mass stationary. Calculations suggest that the HTS gravimeter would be as sensitive as present-day superconducting gravimeters that need cooling to liquid helium temperatures, but the HTS gravimeter needs cooling only to liquid nitrogen temperatures.

  4. (CaFeAs){sub 10}Pt{sub z}As{sub 8} superconductors and related compounds

    Energy Technology Data Exchange (ETDEWEB)

    Stuerzer, Tobias

    2015-04-13

    The main topic of this dissertation is the identification of new compounds, structure determination, and substitution dependent investigation of properties in this new branch of the family of iron arsenide superconductors (Chapter 2). Chapter 2.1 presents the identification of the superconducting compounds and the corresponding structure elucidation identifying two dif-ferent species (CaFeAs){sub 10}Pt{sub 3}As{sub 8} and (CaFeAs){sub 10}Pt{sub 4}As{sub 8} in this family (abbreviated as 1038 and 1048 according to their stoichiometry). However, a closer look revealed a more challenging structure chemistry which is covered in Chapter 2.2. The following two Chapters 2.3 and 2.4 are devoted to (CaFeAs){sub 10}Pt{sub 3}As{sub 8} and more detailed investigations on this parent compound of the new superconductor family. Furthermore, transition metal substitution series (CaFe{sub 1-x}M{sub x}As){sub 10}Pt{sub 3}As{sub 8} were synthesized to investigate the resemblance to model systems Ba(Fe{sub 1-x}M{sub x}){sub 2}As{sub x} and LaO(Fe{sub 1-x}M{sub x})As in the scope of structural changes and superconductivity as described in Chapter 2.5. Initially amazing differences in superconducting properties com-paring 1038 and 1048 compounds are analyzed in Chapter 2.6 establishing an universal dop-ing model in the (CaFe{sub 1-x}M{sub x}As){sub 10}Pt{sub z}As{sub 8} family. Additionally substituent dependent properties upon rare earth substitution in electron doped (Ca{sub 1-y}RE{sub y}FeAs){sub 10}Pt{sub 3}As{sub 8} are investigated in Chapter 2.7, while a detailed study of superconducting properties and magnetism in (Ca{sub 1-y}La{sub y}FeAs){sub 10}Pt{sub 3}As{sub 8} by the local μSR technique is presented in Chapter 2.8. In Chapter 2.9 a comparison of direct and electron doping is discussed based on codoping experiments in (Ca{sub 1-y}La{sub y}Fe{sub 1-x}Pt{sub x}As){sub 10}Pt{sub 3}As{sub 8} and (CaFe{sub 1-x}Pt{sub x}As){sub 10}Pt{sub 4}As{sub 8}. Finally, in Chapter 2

  5. Hybrid superconductor magnet bearings

    Science.gov (United States)

    Chu, Wei-Kan

    1995-01-01

    Hybrid superconductor magnet bearings (HSMB's) utilize high temperature superconductors (HTS's) together with permanent magnets to form a frictionless interface between relatively rotating parts. They are low mass, stable, and do not incur expenditure of energy during normal operation. There is no direct physical contact between rotor and stator, and hence there is no wear and tear. However, just as any other applications of HTS's, it requires a very cold temperature to function. Whereas this might be perceived as a disadvantage on earth, it is of no great concern in space or on the moon. To astronomers, the moon is an excellent site for an observatory, but the cold and dusty vacuum environment on the moon precludes the use of mechanical bearings on the telescope mounts. Furthermore, drive mechanisms with very fine steps, and hence bearings with extremely low friction are needed to track a star from the moon, because the moon rotates very slowly. All aspects considered, the HSMB is about the only candidate that fits in naturally. Here, we present a design for one such bearing, capable of supporting a telescope that weighs about 3 lbs on Earth.

  6. The improved damping of superconductor bearings for 35 kWh superconductor flywheel energy storage system

    Energy Technology Data Exchange (ETDEWEB)

    Han, Y.H., E-mail: yhhan@kepri.re.kr [KEPCO Research Institute, 105 Munji-Ro, Yuseong-Gu, Daejeon 305-760 (Korea, Republic of); Park, B.J.; Jung, S.Y.; Han, S.C.; Lee, W.R.; Bae, Y.C. [KEPCO Research Institute, 105 Munji-Ro, Yuseong-Gu, Daejeon 305-760 (Korea, Republic of)

    2013-02-14

    Highlights: ► We made a 35 kWh superconductor flywheel energy storage system. ► The damping coefficient of the superconductor bearing was increased over 3000 N s/m. ► The source of damping was discussed. -- Abstract: A 35 kWh Superconductor Flywheel Energy Storage system (SFES) using hybrid bearing sets, which is composed of a high temperature superconductor (HTS) bearing and an active magnet damper (AMD), has been developed at KEPCO Research Institute (KEPRI). Damping is a source of energy loss but necessary for the stability of the flywheel system. We found that the damping of HTS bearings can be improved by thermal insulating bolts, which play a role of passive type external damper. To investigate the source of the increased damping, damping coefficients were measured with HTS bearings using insulating bolts made of three kinds of polymer materials. The damping coefficient was raised over 3000 N s/m in the case of PEEK bolts. The value was almost a quarter of the AMD. In this study, thermoelastic and Coulomb friction damping mechanisms are discussed. The main damping mechanism was the thermoelastic damping of the bolts themselves. And interfacial gap between the insulating bolt and metal chamber, which increased during the cooling process, was considered to be the cause of the anisotropic damping coefficients. Finally, the effects of the HTS bearings on the first critical speed are shown.

  7. High levitation pressures with cage-cooled superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R. [Energy Technology Division, Argonne National Laboratory, Argonne, IL (United States); Komori, Mochimitsu [Department of Mechanical Systems Engineering, Kyushu Institute of Technology, Iizuka, Fukuoka (Japan)

    2002-05-01

    We present an analysis of and experimental results from a levitational system comprising a stationary, bulk high-temperature superconductor (HTS) and a levitated component (rotor) that consists of a cylindrical permanent magnet surrounded by an annular HTS. The rotor is cooled below the critical temperature of the HTS while surrounded by a ferromagnetic cage. When the ferromagnetic cage is removed, the flux from the permanent magnet is essentially excluded from the interior of the HTS. When brought into proximity with the HTS stator, the cage-cooled rotor experiences a levitational force. The levitational force may be calculated by applying magnetic circuit theory. Such calculations indicate that for a sufficiently high critical current density, the levitational pressure may exceed that between the permanent magnet and its mirror image. We constructed a rotor from an NdFeB permanent magnet and YBCO bulk HTS with a critical current density of {approx}5 kA cm{sup -2}. A soft ferromagnetic steel cage was constructed in segments. The critical current density of the stator HTS was also {approx}5 kA cm{sup -2}. Experimental results obtained with the cage-cooled rotor and stationary HTS show a significant increase in force over that of an equivalent PM rotor and stationary HTS. (author)

  8. High levitation pressures with cage-cooled superconductors

    Science.gov (United States)

    Hull, John R.; Komori, Mochimitsu

    2002-05-01

    We present an analysis of and experimental results from a levitational system comprising a stationary, bulk high-temperature superconductor (HTS) and a levitated component (rotor) that consists of a cylindrical permanent magnet surrounded by an annular HTS. The rotor is cooled below the critical temperature of the HTS while surrounded by a ferromagnetic cage. When the ferromagnetic cage is removed, the flux from the permanent magnet is essentially excluded from the interior of the HTS. When brought into proximity with the HTS stator, the cage-cooled rotor experiences a levitational force. The levitational force may be calculated by applying magnetic circuit theory. Such calculations indicate that for a sufficiently high critical current density, the levitational pressure may exceed that between the permanent magnet and its mirror image. We constructed a rotor from an NdFeB permanent magnet and YBCO bulk HTS with a critical current density of ≈5 kA cm-2. A soft ferromagnetic steel cage was constructed in segments. The critical current density of the stator HTS was also ≈5 kA cm-2. Experimental results obtained with the cage-cooled rotor and stationary HTS show a significant increase in force over that of an equivalent PM rotor and stationary HTS.

  9. The Development and Demonstration of a 360m/10 kA HTS DC Power Cable

    Science.gov (United States)

    Xiao, Liye

    With the quick development of renewable energy, it is expected that the electric power from renewable energy would be the dominant one for the future power grid. Due to the specialty of the renewable energy, the HVDC power transmission would be very useful for the transmission of electric power from renewable energy. DC power cable made of High Tc Superconductor (HTS) would be a possible alternative for the construction of HVDC power transmission system. In this chapter, we report the development and demonstration of a 360 m/10 kA HTS DC power cable and the test results.

  10. A simulation study on the variation of virtual NMR signals by winding, bobbin, spacer error of HTS magnet

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jun Seong; Lee, Woo Seung; Kim, Jin Sub; Song, Seung Hyun; Nam, Seok Ho; Jeon, Hae Ryong; Beak, Geon Woo; Ko, Tae Kuk [Yonsei University, Seoul (Korea, Republic of)

    2016-09-15

    Recently, production technique and property of the High-Temperature Superconductor (HTS) tape have been improved. Thus, the study on applying an HTS magnet to the high magnetic field application is rapidly increased. A Nuclear Magnetic Resonance (NMR) spectrometer requires high magnitude and homogeneous of central magnetic field. However, the HTS magnet has fabrication errors because shape of HTS is tape and HTS magnet is manufactured by winding HTS tape to the bobbin. The fabrication errors are winding error, bobbin diameter error, spacer thickness error and so on. The winding error occurs when HTS tape is departed from the arranged position on the bobbin. The bobbin diameter and spacer thickness error occur since the diameter of bobbin and spacer are inaccurate. These errors lead magnitude and homogeneity of central magnetic field to be different from its ideal design. The purpose of this paper is to investigate the effect of winding error, bobbin diameter error and spacer thickness error on the central field and field homogeneity of HTS magnet using the virtual NMR signals in MATLAB simulation.

  11. Development and construction of an HTS rotor for ship propulsion application

    Science.gov (United States)

    Nick, W.; Frank, M.; Kummeth, P.; Rabbers, J. J.; Wilke, M.; Schleicher, K.

    2010-06-01

    A low-speed high-torque HTS machine is being developed at Siemens on the basis of previous steps (400kW demonstrator, 4MVA generator). The goal of the programme is to utilize the characteristic advantages offered by electrical machines with HTS-excited rotor, such as efficiency, compact size, and dynamic performance. To be able to address future markets, requirements from ship classification as well as potential customers have to be met. Electromagnetic design cannot be focused on nominal operation only, but has to deal with failure modes like short circuit too. Utilization of superconductor requires to consider margins taking into account that the windings have to operate reliably not only in "clean" laboratory conditions, but in rough environment with the stator connected to a power converter. Extensive quality control is needed to ensure homogenous performance (current capacity, electrical insulation, dimensions) for the large quantity of HTS (45 km). The next step was to set up and operate a small-scale "industrial" manufacturing process to produce HTS windings in a reproducible way, including tests at operating conditions. A HTS rotor includes many more components compared to a conventional one, so tough geometric tolerances must be met to ensure robust performance of the system. All this gives a challenging task, which will be concluded by cold testing of the rotor in a test facility. Then the rotor will be delivered for assembly to the stator. In following machine tests the performance of the innovative HTS drive system will be demonstrated.

  12. Potential aerospace applications of high temperature superconductors

    Science.gov (United States)

    Selim, Raouf

    1994-01-01

    The recent discovery of High Temperature Superconductors (HTS) with superconducting transition temperature, T(sub c), above the boiling point of liquid nitrogen has opened the door for using these materials in new and practical applications. These materials have zero resistance to electric current, have the capability of carrying large currents and as such have the potential to be used in high magnetic field applications. One of the space applications that can use superconductors is electromagnetic launch of payloads to low-earth-orbit. An electromagnetic gun-type launcher can be used in small payload systems that are launched at very high velocity, while sled-type magnetically levitated launcher can be used to launch larger payloads at smaller velocities. Both types of launchers are being studied by NASA and the aerospace industry. The use of superconductors will be essential in any of these types of launchers in order to produce the large magnetic fields required to obtain large thrust forces. Low Temperature Superconductor (LTS) technology is mature enough and can be easily integrated in such systems. As for the HTS, many leading companies are currently producing HTS coils and magnets that potentially can be mass-produced for these launchers. It seems that designing and building a small-scale electromagnetic launcher is the next logical step toward seriously considering this method for launching payloads into low-earth-orbit. A second potential application is the use of HTS to build sensitive portable devices for the use in Non Destructive Evaluation (NDE). Superconducting Quantum Interference Devices (SQUID's) are the most sensitive instruments for measuring changes in magnetic flux. By using HTS in SQUID's, one will be able to design a portable unit that uses liquid nitrogen or a cryocooler pump to explore the use of gradiometers or magnetometers to detect deep cracks or corrosion in structures. A third use is the replacement of Infra-Red (IR) sensor leads on

  13. Statistical correlations for thermophysical properties of Supercritical Argon (SCAR) used in cooling of futuristic High Temperature Superconducting (HTS) cables

    Science.gov (United States)

    Kalsia, Mohit; Dondapati, Raja Sekhar; Usurumarti, Preeti Rao

    2017-05-01

    High Temperature Superconducting (HTS) cables are emerging as an alternative to conventional cables in efficient power transmission. However, these HTS cables require cooling below the critical temperature of superconductors used to transmit larger currents. With the invention of high temperature superconductors whose critical temperatures are up to 134 K (Hg based), it is a great challenge to identify a suitable coolant which can carry away the heating load on the superconductors. In order to accomplish such challenge, an attempt has been made in the present work to propose supercritical Argon (SCAR) as the alternative to cool the HTS cables. Further, a statistical correlation has been developed for the thermophysical properties such as density, viscosity, specific heat and thermal conductivity of SCAR. In addition, the accuracy of developed correlations is established with the help of few statistical parameters and validated with standard database available in the literature. These temperature dependent accurate correlations are useful in predicting the pressure drop and heat transfer behaviour in HTS cables using numerical or computational techniques. In recent times, with the sophistication of computer technology, solving of various complex transport equations along with the turbulence models became popular and hence the developed correlations would benefit the technological community. It is observed that, a decrease in pressure, density and viscosity are found to be decreasing whereas the thermal conductivity and specific heat increase significantly. It can be concluded that higher heat transfer rate and lower pumping power can be achieved with SCAR as coolant in the HTS cables.

  14. Large Scale Applications of HTS in New Zealand

    Science.gov (United States)

    Wimbush, Stuart C.

    New Zealand has one of the longest-running and most consistently funded (relative to GDP) programmes in high temperature superconductor (HTS) development and application worldwide. As a consequence, it has a sustained breadth of involvement in HTS technology development stretching from the materials discovery right through to burgeoning commercial exploitation. This review paper outlines the present large scale projects of the research team at the newly-established Robinson Research Institute of Victoria University of Wellington. These include the construction and grid-based testing of a three-phase 1 MVA 2G HTS distribution transformer utilizing Roebel cable for its high-current secondary windings and the development of a cryogen-free conduction-cooled 1.5 T YBCO-based human extremity magnetic resonance imaging system. Ongoing activities supporting applications development such as low-temperature full-current characterization of commercial superconducting wires and the implementation of inductive flux-pump technologies for efficient brushless coil excitation in superconducting magnets and rotating machines are also described.

  15. Novel processing of HTS based conductors

    Science.gov (United States)

    Ginley, D. S.; Venturini, E. L.; Kwak, J. F.; Baughman, R. J.; Bourcier, R. J.; Mitchell, M. A.; Morosin, B.; Halloran, J. W.; Neal, N. J.; Capone, D. W.

    1990-04-01

    Conductor development is one of the major long term goals in high temperature superconductor research. Two promising processing technologies that were utilized to produce superconducting HTS conductors are reported. First, melt spun YBa2Cu3O7 fibers rapid thermal processed for 1 to 8 sec at 950 to 1075 C have (Tc)'s to 92 K, J(sub c)'s to 1100 A/sq cm and the orthorhombic twinned morphology typical for high quality YBa2Cu3O7. A processing matrix of time, temperature and composition for these fibers shows that slightly CuO-rich starting compositions give the best results. Second, silver tube encapsulated wires of Bi(1.7)Pb(0.3)Sr2Ca2Cu3O10 were made by extrusion, wire drawing and cold rolling. The resulting tapes show orientation of the crystallites, zero resistance up to 100 K and improved magnetic hysteresis above 50 K. The combination of mechanical reprocessing and extended thermal anneals near 850 C appears to significantly improve these materials.

  16. Prospects for the use of HTS in high field magnets for future accelerator facilities

    CERN Document Server

    Ballarino, A

    2014-01-01

    The enthusiasm that followed discovery of High Temperature Superconductors (HTS) and the initial genuine hope of a replacement technology that could have taken over from conventional Low Temperature Superconductors (LTS) was damped during the years by difficulties in reaching performance levels of competing materials: insufficient current-carrying performance, short piece lengths, and fragility of the brittle oxide superconductors made development of applications slow and limited to demonstrators or devices less demanding from the point of view of conductor performance. However, thanks to a continuous R&D effort, significant progress was made in the past years on the development of cuprate superconductors. Today long lengths of BSCCO 2223 (km range) and REBCO (a more general acronym for YBCO, where RE = Rare Earth) tape (hundreds of meters range) conductor with controlled and homogeneous characteristics are commercially available, and tremendous progress has been made in the development of BSSCO 2212 roun...

  17. A nontrivial factor in determining current distribution in an ac HTS cable-proximity effect

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A superconductor has zero resistance at the superconducting state. This unique property creates many exceptional phenomena, of which some are known and the others are not. Our experiments with multilayer high temperature superconductor (HTS) cable samples revealed a new phenomenon that alternating current had a tendency to flow in the inner and outer layers of the cables. We attribute the cause of this phenomenon to the electromagnetic interaction in an infinite electrical conductivity medium and term it "super-proximity-effect". This effect will greatly affect the performance of a multilayer superconducting cable and other superconducting devices which are involved with alternating current transportation.

  18. Collection of Ni-bearing material from electroless plating waste by magnetic separation with HTS bulk magnet

    Energy Technology Data Exchange (ETDEWEB)

    Oka, T., E-mail: okat@eng.niigata-u.ac.jp [Niigata University, 8050 Ikarashi-Ninocho, Nishi-ku, Niigata 950-2181 (Japan); Fukazawa, H.; Fukui, S.; Ogawa, J.; Sato, T.; Ooizumi, M. [Niigata University, 8050 Ikarashi-Ninocho, Nishi-ku, Niigata 950-2181 (Japan); Tsujimura, M. [Aichi Giken Co., 50-1 Takeshita, Hitotugi-cho, Kariya, Aichi 448-0003 (Japan); Yokoyama, K. [Ashikaga Institute of Technology, 268-1 Ohmae-cho, Ashikaga, Tochigi 326-8558 (Japan)

    2014-01-15

    Highlights: ► The magnetic separation for Ni compounds was conducted by HTS bulk magnet. ► The coarse Ni-sulfate crystals were formed from the Ni-phosphite precipitates. ► Ni-sulfate crystals was separated from the mixture of Ni-sulfate and Ni-phosphite compounds. -- Abstract: The magnetic separation experiment to collect the Ni compounds from the waste liquid of electroless plating processes was conducted in the open-gradient magnetic separation process with the high temperature superconducting bulk magnet system. The magnetic pole containing Gd-based bulk superconductors was activated to 3.45 T at 35 K in the static magnetic field of 5 T with use of a superconducting solenoid magnet. The coarse Ni-sulfate crystals were formed by adding the concentrated sulfuric acid to the Ni-phosphite precipitates which yielded from the plating waste liquid by controlling the temperature and the pH value. The open-gradient magnetic separation technique was employed to separate the Ni-sulfate crystals from the mixture of the Ni-sulfate and Ni-phosphite compounds by the difference between their magnetic properties. And we succeeded in collecting Ni-sulfate crystals preferentially to the Ni-phosphite by attracting them to the magnetic pole soon after the Ni-sulfate crystals began to grow.

  19. Preparation, structure and superconductivity of high T(c) compounds: Research of high temperature superconductors in Hungary

    Science.gov (United States)

    Kirschner, I.

    1995-01-01

    In this paper the main directions, methods and results of the investigation of high-T(c) superconductors in Hungary are briefly summarized. The fundamental idea of this research is to study the effect of starting conditions on the microstructure of samples and the influence of the latter one on their superconducting parameters. The investigation concerning technical development is also mentioned.

  20. Enhanced HTS hit selection via a local hit rate analysis.

    Science.gov (United States)

    Posner, Bruce A; Xi, Hualin; Mills, James E J

    2009-10-01

    The postprocessing of high-throughput screening (HTS) results is complicated by the occurrence of false positives (inactive compounds misidentified as active by the primary screen) and false negatives (active compounds misidentified as inactive by the primary screen). An activity cutoff is frequently used to select "active" compounds from HTS data; however, this approach is insensitive to both false positives and false negatives. An alternative method that can minimize the occurrence of these artifacts will increase the efficiency of hit selection and therefore lead discovery. In this work, rather than merely using the activity of a given compound, we look at the presence and absence of activity among all compounds in its "chemical space neighborhood" to give a degree of confidence in its activity. We demonstrate that this local hit rate (LHR) analysis method outperforms hit selection based on ranking by primary screen activity values across ten diverse high throughput screens, spanning both cell-based and biochemical assay formats of varying biology and robustness. On average, the local hit rate analysis method was approximately 2.3-fold and approximately 1.3-fold more effective in identifying active compounds and active chemical series, respectively, than selection based on primary activity alone. Moreover, when applied to finding false negatives, this method was 2.3-fold better than ranking by primary activity alone. In most cases, novel hit series were identified that would have otherwise been missed. Additional uses of and observations regarding this HTS analysis approach are also discussed.

  1. Concepts for using trapped-flux HTS in motors and generators

    Science.gov (United States)

    Hull, John R.; Strasik, Michael

    2013-01-01

    We examine the expected performance of a brushless motor/generator that uses trapped-flux (TF) bulk high-temperature superconductors (HTSs) to provide magnetomotive force, where the stator windings are used to create the TF. A key feature is the use of dysprosium (Dy) for the stator and rotor cores. We also examine methods to energize TF in HTS for generators used in pulsed-power applications.

  2. Manufacturing of Superconductors

    DEFF Research Database (Denmark)

    Bech, Jakob Ilsted; Bay, Niels

    Superconducting tapes based on the ceramic high temperature superconductor (HTS) is a new promising product for high current applications such as electro-magnets and current transmission cables. The tapes are made by the oxide powder in tube (OPIT) method implying drawing and rolling of silver...... on the mechanical and thermal processes applied. One of the most crucial processes is probably the flat rolling process, where the round or square wire is rolled to form a thin tape (about 3 mm x 0.2 mm), while the density of the powder fibres increase and the fibres obtain their final geometry. For instance...... rolling a tape to a thickness of 250 µm may give a very high Je, whereas further reduction to 200 µm may be fatal. In the present work the flat rolling process is analysed systematically from a mechanical forming point of view. This work implies · Mechanical characterisation of the plastic parameters...

  3. Development of Strengthened Bundle High Temperature Superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Lue, J.W.; Lubell, M.S. [Oak Ridge National Lab., TN (United States); Demko, J.A. [Oak Ridge Inst. for Science and Education, TN (United States); Tomsic, M. [Plastronic, Inc., Troy, OH (United States); Sinha, U. [Southwire Company, Carollton, GA (United States)

    1997-12-31

    In the process of developing high temperature superconducting (HTS) transmission cables, it was found that mechanical strength of the superconducting tape is the most crucial property that needs to be improved. It is also desirable to increase the current carrying capacity of the conductor so that fewer layers are needed to make the kilo-amp class cables required for electric utility usage. A process has been developed by encapsulating a stack of Bi-2223/Ag tapes with a silver or non-silver sheath to form a strengthened bundle superconductor. This process was applied to HTS tapes made by the Continuous Tube Forming and Filling (CTFF) technique pursued by Plastronic Inc. and HTS tapes obtained from other manufacturers. Conductors with a bundle of 2 to 6 HTS tapes have been made. The bundled conductor is greatly strengthened by the non-silver sheath. No superconductor degradation as compared to the sum of the original critical currents of the individual tapes was seen on the finished conductors.

  4. High critical temperature superconductor Josephson junctions for quantum circuit applications

    Energy Technology Data Exchange (ETDEWEB)

    Bauch, T; Gustafsson, D; Cedergren, K; Nawaz, S; Mumtaz Virk, M; Lombardi, F [Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, Goeteborg (Sweden); Pettersson, H; Olsson, E [Department of Applied Physics, Chalmers University of Technology, Goeteborg (Sweden)], E-mail: bauch@chalmers.se

    2009-12-15

    Recent findings of macroscopic quantum properties in high critical temperature superconductor (HTS) Josephson junctions (JJs) point toward the need to revise the role of zero energy quasi-particles in this novel superconductor. We will discuss the possibility of designing superconducting artificial atoms in a transmon configuration to study the low energy excitation spectra of HTS. We have engineered high quality grain boundary JJs on low dielectric constant substrates. By fabricating submicron junctions, we extract values of capacitance and Josephson critical current densities that satisfy the main transmon design requirements. Moreover, the measured critical current noise power extrapolated at 1 Hz gives a dephasing time of 25 ns, which indicates that the observation of macroscopic quantum coherent effects in HTS JJ is a feasible task.

  5. Permanent magnet with MgB{sub 2} bulk superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Akiyasu, E-mail: yamamoto@appchem.t.u-tokyo.ac.jp [The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan); JST-PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Ishihara, Atsushi; Tomita, Masaru [Railway Technical Research Institute, 2-8-38 Hikari, Kokubunji, Tokyo 185-8540 (Japan); Kishio, Kohji [The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan)

    2014-07-21

    Superconductors with persistent zero-resistance currents serve as permanent magnets for high-field applications requiring a strong and stable magnetic field, such as magnetic resonance imaging. The recent global helium shortage has quickened research into high-temperature superconductors (HTSs)—materials that can be used without conventional liquid-helium cooling to 4.2 K. Herein, we demonstrate that 40-K-class metallic HTS magnesium diboride (MgB{sub 2}) makes an excellent permanent bulk magnet, maintaining 3 T at 20 K for 1 week with an extremely high stability (<0.1 ppm/h). The magnetic field trapped in this magnet is uniformly distributed, as for single-crystalline neodymium-iron-boron. Magnetic hysteresis loop of the MgB{sub 2} permanent bulk magnet was determined. Because MgB{sub 2} is a simple-binary-line compound that does not contain rare-earth metals, polycrystalline bulk material can be industrially fabricated at low cost and with high yield to serve as strong magnets that are compatible with conventional compact cryocoolers, making MgB{sub 2} bulks promising for the next generation of Tesla-class permanent-magnet applications.

  6. Design considerations and experimental results for MRI systems using HTS magnets

    Science.gov (United States)

    Parkinson, Ben

    2017-01-01

    An increasing number of magnetic resonance imaging (MRI) systems using high temperature superconductors (HTS) magnets have been designed and constructed, with detailed results of their performance now available. Features of REBCO and BSCCO conductors are described as they pertain to use in high homogeneity magnets, with emphasis placed on the practical use of these conductors in magnets. Methods of coil winding are discussed, in particular the differences between pancake and layer winding techniques. Design considerations for HTS magnets are presented in light of the difficulties presented by quench in these magnets, but also in terms of the features of HTS magnets afforded by their high operating temperatures, namely robust cryogen free operation and the potential to use unshielded gradient coils. Drawing on two example MRI systems, namely a 3 T BSCCO brain imaging magnet developed in Japan and a 1.5 T REBCO orthopaedic imaging system developed in New Zealand, the report details real-world stability and homogeneity of HTS-MRI systems, in particular with regards to the screening current effects observed in these systems. It is concluded that, apart from conductor cost, there are currently no technical obstacles to use of HTS-MRI systems.

  7. Influence of radius of cylinder HTS bulk on guidance force in a maglev vehicle system

    Science.gov (United States)

    Longcai, Zhang

    2014-07-01

    Bulk superconductors had great potential for various engineering applications, especially in a high-temperature superconducting (HTS) maglev vehicle system. In such a system, the HTS bulks were always exposed to AC external magnetic field, which was generated by the inhomogeneous surface magnetic field of the NdFeB guideway. In our previous work, it was observed that the guidance force of the YBCO bulk over the NdFeB guideway used in the HTS maglev vehicle system was decayed by the application of the AC external magnetic field. In this paper, we investigated the influence of the radius of the cylinder HTS bulk exposed to an AC magnetic field perturbation on the guidance force in the maglev vehicle system. From the results, it was found that the guidance force was stronger for the bulk with bigger radius and the guidance force decay rates of the bulks were approximately equal despite of the different radius in the maglev vehicle system. Therefore, in order to obtain higher guidance force in the maglev vehicle system, we could use the cylinder HTS bulks with the bigger radius.

  8. Strengthening future electricity grid of the Netherlands by integration of HTS transmission cables

    Science.gov (United States)

    Zuijderduin, Roy; Chevtchenko, Oleg; Smit, Johan; Aanhaanen, Gert; Ross, Rob

    2014-05-01

    The electricity grid of the Netherlands is changing. There is a call of society to use more underground cables, less overhead lines (OHL) and to reduce magnetic emissions. At the same time, parts of the future transmission grid need strengthening depending on the electricity demand in the coming decades [1]. Novel high temperature superconductor (HTS) AC transmission cables can play a role in strengthening the grid. The advantages as compared to alternatives, are: economic, underground, higher power capacity, lower losses, reduced magnetic field emissions in (existing) OHL, compact: less occupation of land and less permits needed, a possibility to keep 380 kV voltage level in the grid for as long as needed. The main obstacles are: the relatively high price of HTS tapes and insufficient maturity of the HTS cable technology. In the paper we focus on a 34 km long connection in the transmission grid (to be strengthened in three of the four of TenneT scenarios [1]), present the network study results, derive the requirements for corresponding HTS transmission cable system and compare HTS system to the alternatives (OHLs and XLPE cables).

  9. Integration of HTS Cables in the Future Grid of the Netherlands

    Science.gov (United States)

    Zuijderduin, R.; Chevtchenko, O.; Smit, J. J.; Aanhaanen, G.; Melnik, I.; Geschiere, A.

    Due to increasing power demand, the electricity grid of the Netherlands is changing. The future transmission grid will obtain electrical power generated by decentralized renewable sources, together with large scale generation units located at the coastal region. In this way electrical power has to be distributed and transmitted over longer distances from generation to end user. Potential grid issues like: amount of distributed power, grid stability and electrical loss dissipation merit particular attention. High temperature superconductors (HTS) can play an important role in solving these grid problems. Advantages to integrate HTS components at transmission voltages are numerous: more transmittable power together with less emissions, intrinsic fault current limiting capability, lower ac loss, better control of power flow, reduced footprint, less magnetic field emissions, etc. The main obstacle at present is the relatively high price of HTS conductor. However as the price goes down, initial market penetration of several HTS components (e.g.: cables, fault current limiters) is expected by year 2015. In the full paper we present selected ways to integrate EHV AC HTS cables depending on a particular future grid scenario in the Netherlands.

  10. AC HTS Transmission Cable for Integration into the Future EHV Grid of the Netherlands

    Science.gov (United States)

    Zuijderduin, R.; Chevtchenko, O.; Smit, J. J.; Aanhaanen, G.; Melnik, I.; Geschiere, A.

    Due to increasing power demand, the electricity grid of the Netherlands is changing. The future grid must be capable to transmit all the connected power. Power generation will be more decentralized like for instance wind parks connected to the grid. Furthermore, future large scale production units are expected to be installed near coastal regions. This creates some potential grid issues, such as: large power amounts to be transmitted to consumers from west to east and grid stability. High temperature superconductors (HTS) can help solving these grid problems. Advantages to integrate HTS components at Extra High Voltage (EHV) and High Voltage (HV) levels are numerous: more power with less losses and less emissions, intrinsic fault current limiting capability, better control of power flow, reduced footprint, etc. Today's main obstacle is the relatively high price of HTS. Nevertheless, as the price goes down, initial market penetration for several HTS components is expected by year 2015 (e.g.: cables, fault current limiters). In this paper we present a design of intrinsically compensated EHV HTS cable for future grid integration. Discussed are the parameters of such cable providing an optimal power transmission in the future network.

  11. High-T(sub c) Superconductor-Normal-Superconductor Junctions with Polyimide-Passivated Ambient Temperature Edge Formation

    Science.gov (United States)

    Barner, J. B.; Kleinsasser, A. W.; Hunt, B. D.

    1996-01-01

    The ability to controllably fabricate High-Temperature Superconductor (HTS) S-Normal-S (SNS) Josephson Juntions (JJ's) enhances the possibilities fro many applications, including digital circuits, SQUID's, and mixers. A wide variety of approaches to fabricating SNS-like junctions has been tried and analyzed in terms of proximity effect behavior.

  12. Potentialities of HTS Superconductor Technology in Telecommunication Satellites

    Science.gov (United States)

    2005-07-13

    temperature area with the LNA (3). Figure 3 : Global view The temperature in the three areas is controlled by two autonomous Stirling cryo- coolers in...the worse case of complete breakdown. We suppose that the life time of two coolers operating at 50 % is longer than a system of two coolers one...performed on existing Stirling cooler production, as it is done for the high capacity Stirling cooler developed and produced for the CRYOSYSTEM

  13. Potential impact of high temperature superconductors on MAGLEV transportation

    Science.gov (United States)

    Hull, J. R.

    1992-02-01

    This report describes the potential impact that high-temperature superconductors (HTS's) may have on transportation by magnetically levitated vehicles. It is not intended as a planning document, but rather as an overview of potential HTS applications to magnetic-levitation (maglev) transportation. The present maglev program in the United States is summarized, and the present status of development of HTS's is described. Areas identified for possible impact on maglev technology are: (1) liquid-nitrogen-cooled levitation magnets; (2) magnetic-field shielding of the passenger compartment; (3) superconducting magnetic energy storage for wayside power; (4) superconducting bearings for flywheel energy storage for wayside power; (5) downleads to continuously powered liquid-helium-cooled levitation magnets; and (6) liquid-hydrogen-cooled levitation magnets and linear motor propulsion windings. Major technical issues that remain to be resolved for the use of HTS's in maglev applications include thermal magnetic stability, mechanical properties, and critical current density at liquid-nitrogen temperatures.

  14. High temperature superconductors for fusion at the Swiss Plasma Center

    Science.gov (United States)

    Bruzzone, P.; Wesche, R.; Uglietti, D.; Bykovsky, N.

    2017-08-01

    High temperature superconductors (HTS) may become in future an option for the superconducting magnets of commercial fusion plants. At the Swiss Plasma Center (SPC) the R&D activity toward HTS high current, high field cables suitable for fusion magnets started in 2012 and led in 2015 to the assembly of the first 60 kA, 12 T prototype conductor. The cable concept developed at the SPC is based on the principle of ‘soldered, twisted stacks’ of REBCO tapes. The required number of stacks is assembled in a cored flat cable, cooled by forced flow of supercritical helium. The sample environment of the test facility at SPC has been upgraded with a HTS adapter and a counter-flow heat exchanger to allow testing the HTS sample in a broader range of temperature (4.5 K-50 K) using the existing, NbTi based superconducting transformer and the closed loop refrigerator.

  15. Modeling the Effects of Varying the Capacitance, Resistance, Temperature, and Frequency Dependence for HTS Josephson Junctions, DC SQUIDs and DC bi-SQUIDS

    Science.gov (United States)

    2014-09-01

    junction is a thin layer of insulating material sep- arating two superconductors that is thin enough for electrons to tunnel through. Two Josephson...different material and/or method on the bisecting Josephson junction for high temperature superconductor (HTS) YBa2Cu3O7 (YBCO) bi-SQUIDs. This...in the previous case. The transition point (critical current) and hysteresis are both decreased. There are much greater amplitude oscillations for K P

  16. Cryogenic cooling system for HTS cable

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Shigeru [Taiyo Nippon Sanso, Tsukuba (Japan)

    2017-06-15

    Recently, Research and development activity of HTS (High Temperature Superconducting) power application is very progressive worldwide. Especially, HTS cable system and HTSFCL (HTS Fault current limiter) system are proceeding to practical stages. In such system and equipment, cryogenic cooling system, which makes HTS equipment cooled lower than critical temperature, is one of crucial components. In this article, cryogenic cooling system for HTS application, mainly cable, is reviewed. Cryogenic cooling system can be categorized into conduction cooling system and immersion cooling system. In practical HTS power application area, immersion cooling system with sub-cooled liquid nitrogen is preferred. The immersion cooling system is besides grouped into open cycle system and closed cycle system. Turbo-Brayton refrigerator is a key component for closed cycle system. Those two cooling systems are focused in this article. And, each design and component of the cooling system is explained.

  17. Study of superconductor bearings for a 35 kWh superconductor flywheel energy storage system

    Science.gov (United States)

    Han, Y. H.; Park, B. J.; Jung, S. Y.; Han, S. C.

    2012-12-01

    A Superconductor Flywheel Energy Storage system (SFES) is used as an electro-mechanical battery which transforms electrical energy into mechanical energy and vice versa. A 35 kWh SFES using hybrid bearing sets was developed in KEPRI. Mechanical properties of HTS bearings are the critical factors for stability of the flywheel and the main parameter in designing the system. The properties of the HTS bearing were studied. The stiffness and the damping coefficient of the HTS bearing were 346.6 ± 6.7 kN/m and 1255 ± 102 N s/m, respectively. The damping coefficient was twelve times bigger than the estimate value. Therefore, we concluded that there were some external damping mechanisms. Finally, the 35 kWh SFES was test operated up to 4000 rpm. After passing two predicted critical speeds, the amplitude of vibration decreased and reached a stable rotation state.

  18. Pressure-induced superconductor-insulator transition in the spinel compound CuRh2S4.

    Science.gov (United States)

    Ito, M; Hori, J; Kurisaki, H; Okada, H; Perez Kuroki, A J; Ogita, N; Udagawa, M; Fujii, H; Nakamura, F; Fujita, T; Suzuki, T

    2003-08-15

    We performed resistivity measurements in CuRh2S4 under quasihydrostatic pressure of up to 8.0 GPa, and found a pressure-induced superconductor-insulator transition. Initially, with increasing pressure, the superconducting transition temperature T(c) increases from 4.7 K at ambient pressure to 6.4 K at 4.0 GPa, but decreases at higher pressures. With further compression, superconductivity in CuRh2S4 disappears abruptly at a critical pressure P(SI) between 5.0 and 5.6 GPa, when it becomes an insulator.

  19. TECHNICAL TRAINING SEMINAR: High Temperature Superconductors: Progress and Issues

    CERN Multimedia

    Davide Vitè

    2002-01-01

    Monday 24 June from 14:30 to 15:30 - Training Centre Auditorium - bldg. 593-11 High Temperature Superconductors: Progress and Issues Prof. Jan Evetts / UNIVERSITY OF CAMBRIDGE, Department of Materials Science and Metallurgy, UK Grappling with grain boundaries: Current transport processes in granular High Temperature Superconductors (HTS) The development of High Temperature Superconductors, seen from a materials scientist's point of view, is relevant to the superconductivity community at CERN: their possible high current applications can include high performance magnets for future accelerators. There is an urgent need to develop a quantitative description of HTS conductors in terms of their complex anisotropy, inhomogeneity and dimensionality. This is essential both for the practical specification of a conductor and for charting routes to conductor optimisation. The critical current, the n-value, dissipation and quenching characteristics are amongst most important parameters that make up an engineering specifi...

  20. Signature of electron-phonon interaction in high temperature superconductors

    Directory of Open Access Journals (Sweden)

    Vinod Ashokan

    2011-09-01

    Full Text Available The theory of thermal conductivity of high temperature superconductors (HTS based on electron and phonon line width (life times formulation is developed with Quantum dynamical approach of Green's function. The frequency line width is observed as an extremely sensitive quantity in the transport phenomena of HTS as a collection of large number of scattering processes. The role of resonance scattering and electron-phonon interaction processes is found to be most prominent near critical temperature. The theory successfully explains the spectacular behaviour of high Tc superconductors in the vicinity of transition temperature. A successful agreement between theory and experiment has been obtained by analyzing the thermal conductivity data for the sample La1.8Sr0.2CuO4 in the temperature range 0 − 200K. The theory is equally and successfully applicable to all other high Tc superconductors.

  1. An introduction to the design and fabrication progress of a megawatt class 2G HTS motor for the ship propulsion application

    Science.gov (United States)

    Moon, Heejong; Kim, Yeong-Chun; Park, Heui-Joo; Yu, In-Keun; Park, Minwon

    2016-03-01

    This paper introduces the design and fabrication progress of a megawatt class 2G high temperature superconductor (HTS) motor for the ship propulsion application at Doosan Heavy Industries and Construction. The purpose of this 2G HTS propulsion motor is to launch the business area for marine applications such as surface ship, submarine, merchant ship etc. The principles and interpretation of the magnetic field for 2G HTS motor and permanent magnet type motors are similar on the basis of 3D design and production. The most important component of an HTS motor is the rotor, which is composed of HTS coil, non-ferrous metal, torque disk, damper, and hollow shaft. A HTS rotor using hastelloy-based 2G HTS coils was designed and built. Open-circuit and short-circuit characteristics of the superconducting motor were investigated and compared with the analysis results at reduced excitation to verify the design. Preliminary testing of a 2G HTS motor has been conducted at a few hundred kilowatts as per the design. Through these results, we anticipate that most of the design criteria can be satisfied. However, we have faced several issues during the testing of the motor and these issues need to be resolved in order to take the design further.

  2. Recent progress of HTS cable project

    Science.gov (United States)

    Masuda, T.; Yumura, H.; Watanabe, M.

    2008-09-01

    A lot of developments of HTS wires and their applications have been conducted since the discovery of HTS materials in the world. It has been recently reported that critical current of BSCCO wires improved to more than 200 A at 77 K and a large amount of wire was provided with high quality as industrial products. This improvement can be expected to accelerate the commercialization of HTS applications such as an HTS cable, HTS motor and so on. As the proofs of such trends, Sumitomo Electric constructed two HTS cable systems and started their operations in the USA and Korea last year. One of them is the HTS cable in Albany, NY, which has a capacity of 34.5 kV and 800 A and 350 m in length. It has been operated in a real grid without any trouble for 9 months. The other is the HTS cable in Korea, which has a capacity of 22.9 kV and 1250 A and 100 m in length. Its operation also started in the KEPCO testing yard last year. These results demonstrate reliance and stability of its operation. Recently, a new national project of an HTS cable has just started in Japan to demonstrate the operation in a real grid and study the system operations including a monitoring method, an alarm system, a maintenance method, etc. This paper reports the results of Albany and Korea projects and an outline of the new project.

  3. High Temperature Superconductor Accelerator Magnets

    CERN Document Server

    AUTHOR|(CDS)2079328; de Rijk, Gijs; Dhalle, Marc

    2016-11-10

    For future particle accelerators bending dipoles are considered with magnetic fields exceeding $20T$. This can only be achieved using high temperature superconductors (HTS). These exhibit different properties from classical low temperature superconductors and still require significant research and development before they can be applied in a practical accelerator magnet. In order to study HTS in detail, a five tesla demonstrator magnet named Feather-M2 is designed and constructed. The magnet is based on ReBCO coated conductor, which is assembled into a $10kA$ class Roebel cable. A new and optimized Aligned Block layout is used, which takes advantage of the anisotropy of the conductor. This is achieved by providing local alignment of the Roebel cable in the coil windings with the magnetic field lines. A new Network Model capable of analyzing transient electro-magnetic and thermal phenomena in coated conductor cables and coils is developed. This model is necessary to solve critical issues in coated conductor ac...

  4. Thermal property of insulation material for HTS power cable

    Science.gov (United States)

    Choi, Yeon Suk; Kim, D. L.; Shin, D. W.; Hwang, S. D.

    2012-06-01

    The thermal property of insulation material is essential in developing a high temperature superconductor (HTS) power cable operating at around liquid nitrogen temperature. The accurate estimate of the heat flux is difficult in the nonmetallic materials because nonmetallic materials have a high thermal resistance and low temperature gradient along the specimen. The objective of the present work is to develop a precise instrument for measuring the thermal conductivity of insulating materials over a temperature range of 30 K to approximately the room temperature by using a cryocooler. The thermal conductivity of Teflon is measured and the accuracy confirmation is carried out by comparing published data. In addition, the experimental results of apparent thermal conductivity of polypropylene laminated paper (PPLP) are presented and the temperature dependency is also discussed

  5. Superconductor-Magnet Bearings With Inherent Stability and Velocity-Independent Drag Torque

    Science.gov (United States)

    Lee, Eun-Jeong; Ma, Ki Bui; Wilson, Thomas L.; Chu, Wei-Kan

    1999-01-01

    A hybrid superconductor magnet bearing system has been developed based on passive magnetic levitation and the flux pinning effect of high-temperature superconductivity. The rationale lies in the unique capability of a high-temperature superconductor (HTS) to enhance system stability passively without power consumption. Characterization experiments have been conducted to understand its dynamic behavior and to estimate the required motor torque for its driving system design. These experiments show that the hybrid HTS-magnet bearing system has a periodic oscillation of drag torque due mainly to the nonuniform magnetic field density of permanent magnets. Furthermore, such a system also suffers from a small superimposed periodic oscillation introduced by the use of multiple HTS disks rather than a uniform annulus of HTS material. The magnitude of drag torque is velocity independent and very small. These results make this bearing system appealing for high-speed application. Finally, design guidelines for superconducting bearing systems are suggested based on these experimental results.

  6. Maximum trapped field of a ring bulk superconductor by low pulsed field magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchimoto, M. [Hokkaido Institute of Technology, 7-15 Maeda, Teine-ku, Sapporo 006-8585 (Japan)], E-mail: tsuchi@hit.ac.jp; Kamijo, H. [Railway Technical Research Institute, 2-8-38, Hikari-cho, Kokubunji, Tokyo 185-8540 (Japan)

    2007-10-01

    Pulsed field magnetization is an important technique for a bulk superconducting magnet, which is one practical application of a bulk high T{sub c} superconductor (HTS). Full magnetization of a ring HTS is effective to obtain large trapped field for low pulsed field magnetization. In this study, trapped field in a ring bulk superconductor by the low pulsed field magnetization is numerically analyzed under assumption of variable shielding current by the temperature control. Differences between one-dimensional Bean model and axisymmetric three-dimensional numerical solution are discussed through the analysis. There is maximum trapped field in the axisymmetric three-dimensional model because of finite thickness of the ring HTS. The shielding current density and inner radius of the ring HTS are discussed to obtain the maximum trapped field.

  7. The improved damping of superconductor bearings for 35 kWh superconductor flywheel energy storage system

    Science.gov (United States)

    Han, Y. H.; Park, B. J.; Jung, S. Y.; Han, S. C.; Lee, W. R.; Bae, Y. C.

    2013-02-01

    A 35 kWh Superconductor Flywheel Energy Storage system (SFES) using hybrid bearing sets, which is composed of a high temperature superconductor (HTS) bearing and an active magnet damper (AMD), has been developed at KEPCO Research Institute (KEPRI). Damping is a source of energy loss but necessary for the stability of the flywheel system. We found that the damping of HTS bearings can be improved by thermal insulating bolts, which play a role of passive type external damper. To investigate the source of the increased damping, damping coefficients were measured with HTS bearings using insulating bolts made of three kinds of polymer materials. The damping coefficient was raised over 3000 N s/m in the case of PEEK bolts. The value was almost a quarter of the AMD. In this study, thermoelastic and Coulomb friction damping mechanisms are discussed. The main damping mechanism was the thermoelastic damping of the bolts themselves. And interfacial gap between the insulating bolt and metal chamber, which increased during the cooling process, was considered to be the cause of the anisotropic damping coefficients. Finally, the effects of the HTS bearings on the first critical speed are shown.

  8. Space qualification mechanical tests of HTS filters for satellite application

    Institute of Scientific and Technical Information of China (English)

    HUANG JianDong; LI Hong; GU ChangZhi; LUO Qiang; SUN QinFen; WANG XiaoLin; SUN YiFan; WANG ZhiBing; WANG YunFei; LUO Sheng; HE YuSheng; SUN Liang; LI ShunZhou; MENG QingDuan; ZHANG Qiang; LI Fei; ZHANG XueQiang; LI ChunGuang; HE AiSheng

    2007-01-01

    High performance high-temperature superconducting (HTS) filters have been designed and constructed for satellite application. The filters are actually a superconducting integration of an 8-pole band-pass filter with an adjustable band-stop filter onto a single piece of LaAlO3 substrate (with dimension of 0.5×45×20 mm3). Typical results of the filters,i.e.,Filters A (made by YBCO) & B (made by TBCCO) will be reported. The measured responses of Filter A showed excellent specifications,e.g.,an insertion loss less than 0.1 dB,a return loss better than -22.5 dB in pass-band,band-edge steepness greater than 12 dB/MHz and out-of-band rejection at a certain band deeper than -110 dB. To satisfy the requirement of rocket launch and space operation,three filters of the above design have undergone mechanical environmental simulation tests for space qualification. Detailed analysis of the response curves of Filter B measured before and after the tests showed that no noticeable change in the performance can be found. All the filters passed the rigorous ground simulation tests,which is the first time in China for HTS devices and provided a solid foundation for satellite applications of high-temperature superconductors in the near future.

  9. Woodard–Cody anomalous resistivity in a Nb{sub 5}Ge{sub 3}C{sub 0.3} superconductor compound

    Energy Technology Data Exchange (ETDEWEB)

    Bortolozo, Ausdinir D., E-mail: ausdinir.bortolozo@fca.unicamp.br [School of Applied Sciences/FCA, Research Group in Manufacturing of Advanced Materials, University of Campinas, UNICAMP, Campus Limeira, 1300, Pedro Zaccaria St., Jd. Sta Luiza, 13484-350 Limeira, SP (Brazil); Osorio, Wislei R. [School of Applied Sciences/FCA, Research Group in Manufacturing of Advanced Materials, University of Campinas, UNICAMP, Campus Limeira, 1300, Pedro Zaccaria St., Jd. Sta Luiza, 13484-350 Limeira, SP (Brazil); Santos, Carlos Alberto M. dos; Machado, Antônio Jefferson S. [School of Engineering of Lorena –São Paulo University State, P. O. Box 116, Lorena, SP 12600-970 (Brazil)

    2016-08-01

    A normal-state electrical resistivity of a superconducting Nb{sub 5}Ge{sub 3}C{sub 0.3} compound is investigated. Resistivity data are taken from the superconducting transition temperature T{sub c} at room temperature. The data are discussed based on important theoretical expressions in order to explain the normal-state resistivity of the Nb{sub 5}Ge{sub 3}C{sub 0.3} compound. Focusing on the best fitting Woodward and Cody model is used. An 0.77 electron–phonon coupling (λ) is determined, which induces an important role of the electron–phonon coupling for a Nb{sub 5}Ge{sub 3}C{sub 0.3} compound. The saturation of the ρ(T) at 300 K indicates that the mean free path l of the carriers is actually longer than the unit cell dimensions. The negative curvature of this superconductor is a result of the mean free path non-linear in their resulting perturbation. It is also found that the magnitude of the temperature-dependent (phonon) correlated with the resistivity decreases with the decreasing of the mean free path in the absence of phonons due to an atomic disorder induced by lattice intrinsic defects.

  10. 373 K Superconductors

    CERN Document Server

    Kostadinov, Ivan Zahariev

    2016-01-01

    Experimental evidence of superconductors with critical temperatures above $373\\:K$ is presented. In a family of different compounds we demonstrate the superconductor state, the transition to normal state above $387\\:K$, an intermediate $242\\:K$ superconductor, susceptibility up to $350\\:K$, $I-V$ curves at $4.2\\:K$ in magnetic field of $12\\:T$ and current up to $60\\:A$, $300\\:K$ Josephson Junctions and Shapiro steps with radiation of $5\\:GHz$ to $21\\:THz$, $300\\:K$ tapes tests with high currents up to $3000\\:A$ and many $THz$ images of coins and washers. Due to a pending patent, the exact chemical characterization and technological processes for these materials are temporarily withheld and will be presented elsewhere.

  11. Statistical analysis for HTS coil considering inhomogeneous Ic distribution of HTS tape

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Hong Woo; Lee, Ji Ho; Lee, Woo Seung; Ko, Tae Kuk [Yonsei University, Seoul (Korea, Republic of)

    2015-06-15

    Critical current of high-temperature superconducting (HTS) coil is influenced by its own self magnetic field. Direction and density distribution of the magnetic field around the coil are fixed after the shape of the coil is decided. If the entire part of the HTS tape has homogeneous Ic distribution characteristic, quench would be initiated in fixed location on the coil. However, the actual HTS tape has inhomogeneous Ic distribution along the length. If the Ic distribution of the HTS tape is known, we can expect the spot within the HTS coil that has the highest probability to initiate the quench. In this paper, Ic distribution within the HTS coil under self-field effect is simulated by MATLAB. In the simulation procedure, Ic distribution of the entire part of the HTS tape is assume d to follow Gaussian-distribution by central limit theorem. The HTS coil model is divided into several segments, and the critical current of each segment is calculated based on the-generalized Kim model. Single pancake model is simulated and self-field of HTS coil is calculated by Biot-Savart's law. As a result of simulation, quench-initiating spot in the actual HTS coil can be predicted statistically. And that statistical analysis can help detect or protect the quench of the HTS coil.

  12. Development and construction of an HTS rotor for ship propulsion application

    Energy Technology Data Exchange (ETDEWEB)

    Nick, W; Frank, M; Kummeth, P; Rabbers, J J; Wilke, M; Schleicher, K, E-mail: wolfgang.nick@siemens.co [Siemens AG, CT PS 3, Guenther-Scharowsky-Str. 1, D-91050 Erlangen (Germany)

    2010-06-01

    A low-speed high-torque HTS machine is being developed at Siemens on the basis of previous steps (400kW demonstrator, 4MVA generator). The goal of the programme is to utilize the characteristic advantages offered by electrical machines with HTS-excited rotor, such as efficiency, compact size, and dynamic performance. To be able to address future markets, requirements from ship classification as well as potential customers have to be met. Electromagnetic design cannot be focused on nominal operation only, but has to deal with failure modes like short circuit too. Utilization of superconductor requires to consider margins taking into account that the windings have to operate reliably not only in 'clean' laboratory conditions, but in rough environment with the stator connected to a power converter. Extensive quality control is needed to ensure homogenous performance (current capacity, electrical insulation, dimensions) for the large quantity of HTS (45 km). The next step was to set up and operate a small-scale 'industrial' manufacturing process to produce HTS windings in a reproducible way, including tests at operating conditions. A HTS rotor includes many more components compared to a conventional one, so tough geometric tolerances must be met to ensure robust performance of the system. All this gives a challenging task, which will be concluded by cold testing of the rotor in a test facility. Then the rotor will be delivered for assembly to the stator. In following machine tests the performance of the innovative HTS drive system will be demonstrated.

  13. High output power reluctance electric motors with bulk high-temperature superconductor elements

    Science.gov (United States)

    Kovalev, L. K.; Ilushin, K. V.; Penkin, V. T.; Kovalev, K. L.; Larionoff, A. E.; M-A Koneev, S.; Modestov, K. A.; Larionoff, S. A.; Poltavets, V. N.; Akimov, I. I.; Alexandrov, V. V.; Gawalek, W.; Oswald, B.; Krabbes, G.

    2002-05-01

    We present new types of electric machines with the rotors containing bulk high-temperature superconductor (HTS) - YBCO and Bi-Ag - elements. We discuss different schematics of hysteresis, reluctance, 'trapped field' and composed synchronous HTS machines. The two-dimensional mathematical models describing the processes in such types of HTS machines were developed on the basis of the theoretical analysis of the electrodynamic and hysteresis processes in the single-domain and polycrystal YBCO ceramic samples and plate shape Bi-Ag elements. We give the test results of the series of hysteresis, reluctance, 'trapped field' and composed with permanent magnets HTS motors with an output power rating of 0.1-18 kW and current frequencies 50 Hz and 400 Hz. These results show that in the media of liquid nitrogen the specific output power per one unit weight of the HTS motor is four to seven times better than for conventional electric machines. A comparison of the theoretical and experimental characteristics of the developed HTS motors show that they are in good agreement. We discuss the test results for a liquid nitrogen cryogenic pump system with a hysteresis 500 W HTS motor. We describe several designs of new HTS motors operating in the media of liquid nitrogen with an output power 125 kW (and more) and a power factor of more than 0.8. We discuss future applications of new types of HTS motors for aerospace technology, on-land industry and transport systems.

  14. Development of Y-Ba-Cu-O Superconductors for Magnetic Bearings

    Science.gov (United States)

    Selvamanickam, V.; Pfaffenbach, K.; Sokolowski, R. S.; Zhang, Y.; Salama, K.

    1996-01-01

    The material requirements, material manufacturing and magnetic properties that are relevant to fabrication of High Temperature Superconductor (HTS) magnetic bearings have been discussed. It is found that the seeded-melt-texturing method can be used to fabricate the single domain material that is required to achieve the best magnetic properties. Trapped-field mapping has been used as a non-destructive tool to determine the single-domain nature of the HTS material and quantity of the HTS disks. Both the trapped field and the levitation force of the Y-Ba-Cu-O disks are found to be strongly sensitive to the oxygen content.

  15. The magnetostriction in a superconductor-magnet system under non-uniform magnetic field

    Science.gov (United States)

    Li, Xueyi; Jiang, Lang; Wu, Hao; Gao, Zhiwen

    2017-03-01

    This paper describes a numerical model to examine the magnetostriction of bulk high-temperature superconductor (HTS) under non-uniform magnetic field in conjunction with finite element analysis. Through this model, the magnetostriction of homogeneous and nonhomogeneous HTS can be implemented under non-uniform magnetic field. Further, the effects of critical current density, applied field frequency and amplitude are also considered. The computational study can provide a fundamental mechanistic understanding the effects of non-uniform magnetic field on magnetostriction of HTS.

  16. Design of TE01δ Test Probe for Measuring the Microwave Surface Resistance of HTS Thin Film

    Institute of Scientific and Technical Information of China (English)

    Cheng Zeng; Zheng-Xiang Luo; Qi-Shao Zhang; Kai Yang

    2008-01-01

    A new TE01δ test probe with proper transmission factor is fabricated for the measurement of surface resistance of high temperature superconductor (HTS) thin film. Coupling holes instead of coupling loops are used in the probe for its easier machining and relatively low loss. Two 6 mm × 3 mm × 8 mm dielectric waveguides, one side of them is coated by silver, are used for coupling. The measurement result of S21 agrees well with the simulation because the size of the probe can be rigidly controlled by machine. The microwave surface resistance of four YBCO/MgO films are measured at 77 K and 12 GHz and scaled to 10 GHz according to the f 2 rule. The average surface resistance of four HTS thin films is 0.38 mΩ, the standard deviation and relative standard deviation of one single HTS thin film are 0.009 mΩ and 2.4%, respectively.

  17. Analysis and experimental validation of an HTS linear synchronous propulsion prototype with HTS magnetic suspension

    Energy Technology Data Exchange (ETDEWEB)

    Jin Jianxun, E-mail: jxjin@uestc.edu.cn [Center of Applied Superconductivity and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu 611731 (China); Zheng Luhai [Center of Applied Superconductivity and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu 611731 (China); Guo Youguang; Xu Wei; Zhu Jianguo [Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, PO Box 123, NSW 2007 (Australia)

    2011-09-15

    An HTS linear synchronous propulsion prototype with an HTSLSM drive is developed. The feasibility of combining an HTSLSM with an HTS magnetic suspension system has been verified. Three different PMGs are studied by ECS method and experiment verification to obtain an optimal one. The prototype has been tested to obtain the performance and thrust characteristics of the HTSLSM. The measurement results benefit the optimal design and control scheme development for an HTSLSM. A high temperature superconducting (HTS) linear propulsion system composed of a single-sided HTS linear synchronous motor (HTSLSM) in its middle and HTS magnetic suspension sub-systems on both sides has been developed. The HTSLSM uses an HTS bulk magnet array on the moving secondary, and the field-trapped characteristics of the HTS bulk using different magnetized methods have been measured and compared to identify their magnetization capability. In order to generate a large levitation force for the system, three different types of permanent magnet guideways (PMGs) have been numerically analyzed and experimentally verified to obtain an optimal PMG. Based on comprehensive experimental prototype tests, the results show that the HTS linear propulsion system can run with stable magnetic suspension having a constant air-gap length, and the thrust characteristics versus the exciting current, working frequency and the air-gap length have also been obtained. This work forms the basis for developing a practical HTS linear propulsion system by using HTS bulks both for propulsion and suspension.

  18. Study of recovery characteristics of 2nd generation HTS tapes with different stabilizers for resistive type superconducting fault current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Jie, E-mail: 1988725sheng@163.com; Zeng, Weina; Ma, Jun; Yao, Zhihao; Li, Zhuyong; Jin, Zhijian; Hong, Zhiyong

    2016-02-15

    Highlights: • Three methods of measuring the recovery time of HTS tapes are compared. • Four tapes with different stabilizers were tested to compare their recovery characteristics. • The HTS tapes with thinner stabilizers have better recovery characteristics. • Encapsulation makes the recovery characteristics of HTS tapes worse. • The results can be reference of the re-reclosed operation time interval. - Abstract: The resistive type superconducting fault current limiter (SFCL) is one of the most important superconducting power applications nowadays. As known, this type of SFCL is settled directly in the power transmission line. When a short fault happens, the temperature of the superconductors in the SFCL will increase sharply due to the huge generated heat. This means the superconductors need time to recover the superconducting properties and be ready for the next short fault. So the recovery characteristics become one of the most crucial features of the resistive type SFCL. In this paper, several different kinds of measuring methods are presented to calculate the recovery time of the HTS tapes, and comparison of these methods is also carried out by a standard test. On basis of this, samples with different kinds of stabilizers are used to explore the influence of stabilizer on their recovery characteristics. In addition, the influence of the encapsulation technology is also discussed in this paper.

  19. Development of a single-phase 330kVA HTS transformer using GdBCO tapes

    Science.gov (United States)

    Hu, Daoyu; Li, Zhuyong; Hong, Zhiyong; Jin, Zhijian

    2017-08-01

    With the mature of manufacture process and technology of high temperature superconductors, the critical current and stability are gradually increased. High temperature superconductors could be used in transformer, current limiter, generator, magnet and etc. This paper focuses on development and characteristic tests of a single-phase high temperature superconducting (HTS) power transformer with capacity of 330 kVA by using GdBCO tapes, which is 1/3 model of a 1 MVA / 10 kV / 0.4 kV HTS transformer. The specifications of iron core, HTS windings and cryostat are described in detail. The iron core is made of silicon steel plate. The arrangement of HTS windings are based on experimental and simulated results. The cryostat with a room temperature bore is manufactured using nonmetallic materials. Several characteristic tests and insulation tests are performed in liquid nitrogen of 77 K. The efficiency and AC loss at rated load is 99.90% and 243.7 W, respectively. In addition, an overload test was also performed.

  20. Manufacturing and test of 2G-HTS coils for rotating machines: Challenges, conductor requirements, realization

    Energy Technology Data Exchange (ETDEWEB)

    Oomen, Marijn, E-mail: marijn.oomen@siemens.com [Siemens AG, Corporate Technology, CT T DE HW4, PO Box 3220, 91050 Erlangen (Germany); Herkert, Werner; Bayer, Dietmar; Kummeth, Peter; Nick, Wolfgang; Arndt, Tabea [Siemens AG, Corporate Technology, CT T DE HW4, PO Box 3220, 91050 Erlangen (Germany)

    2012-11-20

    We investigate the use of 2nd-generation High-Temperature Superconductors (2G-HTSs) in the rotors of electrical motors and generators. For these devices the conductor must be wound into robust impregnated coils, which are operated in vacuum at temperatures around 30 K, in strong magnetic fields of about 2T. Differences in thermal contraction between the coil former, conductor constituents, impregnation resin, bandage and heat-sink materials (assembled at room temperature) cause mechanical stresses at operating temperature. Rotating-machine operation adds Lorentz forces and challenging centripetal accelerations up to thousands of g. Second generation-HTS conductors withstand large tensile stresses in axial direction and compression in normal direction. However, shear stresses, axial compression, and tension normal to the conductor can cause degradation in superconducting properties. Such stresses can be mitigated by correct choice of materials, coil lay-out and manufacturing process. A certain stress level will remain, which the conductor must withstand. We have manufactured many impregnated round and race-track coils, using different 2G-HTS conductors, and tested them at temperatures from 25 K to 77 K. Degradation of the superconductor in early coils was traced to the mentioned differences in thermal contraction, and was completely avoided in coils produced later. We will discuss appropriate coil-winding techniques to assure robust and reliable superconductor performance.

  1. How filaments can reduce AC losses in HTS coated conductors: a review

    Science.gov (United States)

    Grilli, Francesco; Kario, Anna

    2016-08-01

    Second-generation high-temperature superconductor (HTS) tapes, known also as coated conductors, are very promising tapes for HTS applications, in virtue of their extremely high critical current density, in-field behavior, and mechanical strength. Yet, the extremely large (typically in the range 1000-10 000) width-to-thickness ratio of the superconducting material makes them prone to high power dissipation in the presence of time-varying magnetic fields perpendicular to their flat face—a condition frequently met in several applications. Since the dissipation is directly proportional to the square of the superconductor's width, an obvious way of reducing it is by striating the superconductor into narrow filaments (stripes): in that case, provided that the filaments are electromagnetically uncoupled, the losses are reduced by a factor equal to the number of filaments. In the past two decades, many researchers from groups around the world have tried to apply this idea to practical conductors using different techniques. The aim of this paper is to provide a review of such efforts, focusing on the different approaches to make filamentized conductors, on the effectiveness of the AC loss reduction, and on the applicability of those techniques to long lengths.

  2. Manufacturing and test of 2G-HTS coils for rotating machines: Challenges, conductor requirements, realization

    Science.gov (United States)

    Oomen, Marijn; Herkert, Werner; Bayer, Dietmar; Kummeth, Peter; Nick, Wolfgang; Arndt, Tabea

    2012-11-01

    We investigate the use of 2nd-generation High-Temperature Superconductors (2G-HTSs) in the rotors of electrical motors and generators. For these devices the conductor must be wound into robust impregnated coils, which are operated in vacuum at temperatures around 30 K, in strong magnetic fields of about 2T. Differences in thermal contraction between the coil former, conductor constituents, impregnation resin, bandage and heat-sink materials (assembled at room temperature) cause mechanical stresses at operating temperature. Rotating-machine operation adds Lorentz forces and challenging centripetal accelerations up to thousands of g. Second generation-HTS conductors withstand large tensile stresses in axial direction and compression in normal direction. However, shear stresses, axial compression, and tension normal to the conductor can cause degradation in superconducting properties. Such stresses can be mitigated by correct choice of materials, coil lay-out and manufacturing process. A certain stress level will remain, which the conductor must withstand. We have manufactured many impregnated round and race-track coils, using different 2G-HTS conductors, and tested them at temperatures from 25 K to 77 K. Degradation of the superconductor in early coils was traced to the mentioned differences in thermal contraction, and was completely avoided in coils produced later. We will discuss appropriate coil-winding techniques to assure robust and reliable superconductor performance.

  3. Concepts for using trapped-flux HTS in motors and generators

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R., E-mail: john.r.hull2@boeing.com [Boeing Research and Technology, PO Box 3707, Seattle, WA 98124 (United States); Strasik, Michael [Boeing Research and Technology, PO Box 3707, Seattle, WA 98124 (United States)

    2013-01-15

    Highlights: ► Use of Dy for core material increases t in situ magnetization of trapped-flux HTS. ► Hysteresis loss in Dy needs to be reduced. ► Bootstrap in situ magnetization can be done with two pulsed-power generators. -- Abstract: We examine the expected performance of a brushless motor/generator that uses trapped-flux (TF) bulk high-temperature superconductors (HTSs) to provide magnetomotive force, where the stator windings are used to create the TF. A key feature is the use of dysprosium (Dy) for the stator and rotor cores. We also examine methods to energize TF in HTS for generators used in pulsed-power applications.

  4. Current distribution and stability of LTS/HTS hybrid superconducting conductors

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Current distribution and stability of a hybrid LTS/HTS superconductor, consisting of multifilamentary NbTi/Cu and Bi2223/Ag tapes, were numerically analyzed according to power-law models. The results showed that most of current passed through the LTS and the current increased in the HTS with temperature rise when the transport current was below the critical current of the hybrid conductor. The quench propagation velocity of the hybrid conductor was smaller but its minimum quench energy was larger than those of LTS conductors, indicating that the stability of the hybrid superconducting conductor was effectively improved and a high engineering current density was simultaneously achieved. Finally, a hybrid sample, made by soldering Bi2223/Ag tape onto NbTi/Cu conductor, was prepared and tested successfully at helium temperature. The experimental results qualitatively agreed with the simulated ones.

  5. Influence of Off-Centre Operation on the Performance of HTS Maglev

    Science.gov (United States)

    Gou, Y.; He, D.; Zheng, J.; Ye, C.; Xu, Y.; Sun, R.; Che, T.; Deng, Z.

    2014-03-01

    Owing to instinctive self-stable levitation characteristics, high-temperature superconducting (HTS) maglev using bulk high-temperature superconductors attracts more and more attention from scientists and engineers around the world. In this paper, the levitation force relaxation and guidance force characteristics of a Y-Ba-Cu-O levitation unit with different eccentric distances (EDs) off the center of the permanent magnet guideway were experimentally investigated under field-cooling (FC) conditions. Experimental results indicate that the levitation force slightly increases at small EDs firstly, but degrades with further increasing of EDs. However, the maximum guidance force and its stiffness exhibit enhancement in moderate ED range. The results demonstrate that a properly designed initial FC eccentric distance is important for the practical applications of HTS maglev according to specific requirements like running in curve lines.

  6. Superconductor Composite

    Science.gov (United States)

    Dorris, Stephen E.; Burlone, Dominick A.; Morgan; Carol W.

    1999-02-02

    A superconducting conductor fabricated from a plurality of wires, e.g., fine silver wires, coated with a superconducting powder. A process of applying superconducting powders to such wires, to the resulting coated wires and superconductors produced therefrom.

  7. ToxCast HTS Assay Development and Retrofitting: Strategies ...

    Science.gov (United States)

    A presentation to EC JRC partners on new ToxCast HTS assay methods and strategies to address current limitations to HTS methods Slide presentation to EC JRC partners on new ToxCast HTS assay methods and strategies to address current limitations to HTS methods.

  8. HTS nonlinearities in microwave disk resonators

    Science.gov (United States)

    Collado, Carlos; Mateu, Jordi; Shaw, Timothy J.; O'Callaghan, Juan M.

    2002-08-01

    This article describes a procedure for the calculation of the intermodulation behavior of the TM0 1 0 mode in high temperature superconducting (HTS) disk resonators from a description of the local HTS nonlinearities. Successful cross-checks are performed by comparing the theoretical results with experimental measurements and simulations based on the multiport harmonic balance algorithm for a specific model of HTS nonlinearity. The application of this procedure to the determination of nonlinear material parameters from disk resonator measurements is illustrated and compared to theoretical predictions.

  9. HTS 20 M 600 a link assembled

    CERN Document Server

    Ballarino, A

    2013-01-01

    The final deliverable of the EuCARD Task 7.5 activity is a 20 m long Superconducting Link made of HTS (High Temperature Superconducting) cables of the type and in quantity as required for the powering of the LHC superconducting circuits fed from LHC P7 (50 cables rated at 600 A). Following an intense R&D activity, which included the study of novel concepts of cables made from HTS tape conductor and the development and test of prototype units, the final deliverable was successfully assembled at CERN in May 2013. This document reports on the activity that culminated with the assembly of the 20 m long HTS Superconducting Link.

  10. Two HTS options for a 600 MHz insert of a 1.3 GHz LTS/HTS NMR magnet: YBCO and BSCCO

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, S., E-mail: syhahn@mit.ed [Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139 (United States); Bascunan, J.; Yao, W.; Iwasa, Y. [Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139 (United States)

    2010-11-01

    In 2008, the Phase 3 program to complete a 1.3 GHz (30.5 T) NMR magnet started at the Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology. It comprises two sub-phases, 3A and 3B. In Phase 3A, a 600 MHz high temperature superconductor (HTS) insert magnet (H600) will be designed, constructed, and operated in the bore of a 500 MHz low temperature superconductor (LTS) background magnet. This will be followed by Phase 3B, in which the H600 will be combined with a 700 MHz LTS background magnet to complete a 1.3 GHz NMR LTS/HTS magnet. This paper presents and discusses design issues for two conductor options for H600: BiSCCO-2223 (Bi2223) and coated-YBCO or its variants, here designated as YBCO. For each conductor option, we focused on the following issues: (1) elastic and thermal properties; (2) critical current vs. field performance; (3) splice and index heat dissipations; (4) mechanical and thermal stresses; and (5) protection.

  11. Superconductor Materials-A Revolutionary Value Addition to Space Electronics

    Directory of Open Access Journals (Sweden)

    Rathindra Nath Biswas

    2004-04-01

    Full Text Available An early success in low temperature superconductor technology has led to the development of a number of high temperature superconductor (H TS materials, which have critical temperature above 77 K. When the temperature of a solid is lowered below critical temperature, the material loses its electrical resistivity. Because resistance is almost zero, superconductors can carry very high current, generating very large homogeneous magnetic fields. Due to these features, it is possible to design electronic devices with extremely thin profile, offering less weight and low manufacturing cost. Such exceptional properties have made HTS materials useful in military and space sectors, wherc airborne systems have already provided with cryogenic infrastructure which can he used for cooling a high temperature superconductor at no extra cost.

  12. Production LHC HTS power lead test results

    CERN Document Server

    Tartaglia, M; Fehér, S; Huang, Y; Orris, D F; Pischalnikov, Y; Rabehl, Roger Jon; Sylvester, C D; Zbasnik, J

    2005-01-01

    The Fermilab Magnet test facility has built and operated a test stand to characterize the performance of HTS power leads. We report here the results of production tests of 20 pairs of 7.5 kA HTS power leads manufactured by industry for installation in feed boxes for the LHC Interaction Region quadrupole strings. Included are discussions of the thermal, electrical, and quench characteristics under "standard" and "extreme" operating conditions, and the stability of performance across thermal cycles.

  13. Use of in Vitro HTS-Derived Concentration-Response Data as ...

    Science.gov (United States)

    Background: Quantitative high-throughput screening (qHTS) assays are increasingly being employed to inform chemical hazard identification. Hundreds of chemicals have been tested in dozens of cell lines across extensive concentration ranges by the National Toxicology Program in collaboration with the NIH Chemical Genomics Center. Objectives: To test a hypothesis that dose-response data points of the qHTS assays can serve as biological descriptors of assayed chemicals and, when combined with conventional chemical descriptors, may improve the accuracy of Quantitative Structure-Activity Relationship (QSAR) models applied to prediction of in vivo toxicity endpoints. Methods and Results: The cell viability qHTS concentration-response data for 1,408 substances assayed in 13 cell lines were obtained from PubChem; for a subset of these compounds rodent acute toxicity LD50 data were also available. The classification k Nearest Neighbor and Random Forest QSAR methods were employed for modeling LD50 data using either chemical descriptors alone (conventional models) or in combination with biological descriptors derived from the concentration-response qHTS data (hybrid models). Critical to our approach was the use of a novel noise-filtering algorithm to treat qHTS data. We show that both the external classification accuracy and coverage (i.e., fraction of compounds in the external set that fall within the applicability domain) of the hybrid QSAR models was superior to convent

  14. Enhancement of mechanical properties of 123 superconductors

    Science.gov (United States)

    Balachandran, Uthamalingam

    1995-01-01

    A composition and method of preparing YBa.sub.2 Cu.sub.3 O.sub.7-x superconductor. Addition of tin oxide containing compounds to YBCO superconductors results in substantial improvement of fracture toughness and other mechanical properties without affect on T.sub.c. About 5-20% additions give rise to substantially improved mechanical properties.

  15. Analytical Study of Stress State in HTS Solenoids

    Energy Technology Data Exchange (ETDEWEB)

    Barzi, E.; Terzini, E.; /Fermilab

    2009-01-01

    A main challenge for high field solenoids made of in High Temperature Superconductor (HTS) is the large stress developed in the conductor. This is especially constraining for BSCCO, a brittle and strain sensitive ceramic material. To find parametric correlations useful in magnet design, analytical models can be used. A simple model is herein proposed to obtain the radial, azimuthal and axial stresses in a solenoid as a function of size, i.e. self-field, and of the engineering current density for a number of different constraint hypotheses. The analytical model was verified against finite element modeling (FEM) using the same hypotheses of infinite rigidity of the constraints and room temperature properties. FEM was used to separately evaluate the effect of thermal contractions at 4.2 K for BSCCO and YBCO coils. Even though the analytical model allows for a finite stiffness of the constraints, it was run using infinite stiffness. For this reason, FEM was again used to determine how much stresses change when considering an outer stainless steel skin with finite rigidity for both BSCCO and YBCO coils. For a better understanding of the actual loads that high field solenoids made of HTS will be subject to, we have started some analytical studies of stress state in solenoids for a number of constraint hypotheses. This will hopefully show what can be achieved with the present conductor in terms of self-field. The magnetic field (B) exerts a force F = B x J per unit volume. In superconducting magnets, where the field and current density (J) are both high, this force can be very large, and it is therefore important to calculate the stresses in the coil.

  16. Quench in high temperature superconductor magnets

    CERN Document Server

    Schwartz, J

    2013-01-01

    High field superconducting magnets using high temperature superconductors are being developed for high energy physics, nuclear magnetic resonance and energy storage applications. Although the conductor technology has progressed to the point where such large magnets can be readily envisioned, quench protection remains a key challenge. It is well-established that quench propagation in HTS magnets is very slow and this brings new challenges that must be addressed. In this paper, these challenges are discussed and potential solutions, driven by new technologies such as optical fiber based sensors and thermally conducting electrical insulators, are reviewed.

  17. HTS Wire Development Workshop: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1994-07-01

    The 1994 High-Temperature Superconducting Wire Development Workshop was held on February 16--17 at the St. Petersburg Hilton and Towers in St. Petersburg, Florida. The meeting was hosted by Florida Power Corporation and sponsored by the US Department of Energy`s Superconductivity Program for Electric Power Systems. The meeting focused on recent high-temperature superconducting wire development activities in the Department of Energy`s Superconductivity Systems program. The meeting opened with a general discussion on the needs and benefits of superconductivity from a utility perspective, the US global competitiveness position, and an outlook on the overall prospects of wire development. The meeting then focused on four important technology areas: Wire characterization: issues and needs; technology for overcoming barriers: weak links and flux pinning; manufacturing issues for long wire lengths; and physical properties of HTS coils. Following in-depth presentations, working groups were formed in each technology area to discuss the most important current research and development issues. The working groups identified research areas that have the potential for greatly enhancing the wire development effort. These areas are discussed in the summary reports from each of the working groups. This document is a compilation of the workshop proceedings including all general session presentations and summary reports from the working groups.

  18. Bulk Superconductors in Mobile Application

    Science.gov (United States)

    Werfel, F. N.; Delor, U. Floegel-; Rothfeld, R.; Riedel, T.; Wippich, D.; Goebel, B.; Schirrmeister, P.

    We investigate and review concepts of multi - seeded REBCO bulk superconductors in mobile application. ATZ's compact HTS bulk magnets can trap routinely 1 T@77 K. Except of magnetization, flux creep and hysteresis, industrial - like properties as compactness, power density, and robustness are of major device interest if mobility and light-weight construction is in focus. For mobile application in levitated trains or demonstrator magnets we examine the performance of on-board cryogenics either by LN2 or cryo-cooler application. The mechanical, electric and thermodynamical requirements of compact vacuum cryostats for Maglev train operation were studied systematically. More than 30 units are manufactured and tested. The attractive load to weight ratio is more than 10 and favours group module device constructions up to 5 t load on permanent magnet (PM) track. A transportable and compact YBCO bulk magnet cooled with in-situ 4 Watt Stirling cryo-cooler for 50 - 80 K operation is investigated. Low cooling power and effective HTS cold mass drives the system construction to a minimum - thermal loss and light-weight design.

  19. Time-Correlated Vortex Tunneling in Layered Superconductors

    Directory of Open Access Journals (Sweden)

    John H. Miller

    2017-06-01

    Full Text Available The nucleation and dynamics of Josephson and Abrikosov vortices determine the critical currents of layered high-Tc superconducting (HTS thin films, grain boundaries, and coated conductors, so understanding their mechanisms is of crucial importance. Here, we treat pair creation of Josephson and Abrikosov vortices in layered superconductors as a secondary Josephson effect. Each full vortex is viewed as a composite fluid of micro-vortices, such as pancake vortices, which tunnel coherently via a tunneling matrix element. We introduce a two-terminal magnetic (Weber blockade effect that blocks tunneling when the applied current is below a threshold value. We simulate vortex tunneling as a dynamic, time-correlated process when the current is above threshold. The model shows nearly precise agreement with voltage-current (V-I characteristics of HTS cuprate grain boundary junctions, which become more concave rounded as temperature decreases, and also explains the piecewise linear V-I behavior observed in iron-pnictide bicrystal junctions and other HTS devices. When applied to either Abrikosov or Josephson pair creation, the model explains a plateau seen in plots of critical current vs. thickness of HTS-coated conductors. The observed correlation between theory and experiment strongly supports the proposed quantum picture of vortex nucleation and dynamics in layered superconductors.

  20. Ab initio study of doping effects in the 42214 compounds: A new family of layered iron-based superconductors

    Science.gov (United States)

    Bucci, F.; Sanna, A.; Profeta, G.; Continenza, A.; Gross, E. K. U.

    2017-01-01

    We present a systematic DFT-GGA theoretical characterization of the RE4Fe2As2Te1 -xO4 -yFy family of compounds (conventionally called 42214) as a function of a set of key tuning parameters: rare earth (RE = Pr, Sm, and Gd), Te content, oxygen → fluorine substitutional doping, and external pressure. We focus our discussion on the effect of these parameters on magnetic stability and on the nonmagnetic electronic structure, as most relevant aspects related to the occurrence of superconductivity. To uncover the complexity of the 42214 crystal structure, the electronic analysis is based on an unfolding procedure that allows us to observe the behavior of the hole and electron pockets of the Fermi surface and of the nesting function. We complete the present study with the characterization of a related hypothetical compound having Se substituting for Te. Our results show that this peculiar compound family offers very good opportunities to properly harness material properties; based on our results, we infer that suitably tuning a variety of parameters, as those examined here, improved superconducting properties could be achieved.

  1. Fracture problem of a nonhomogeneous high temperature superconductor slab based on real fundamental solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhiwen, E-mail: gaozhw@lzu.edu.cn; Zheng, Zhiye; Li, Xueyi

    2015-12-15

    Highlights: • We studied firstly nonhomogeneity fracture in HTS base on real fundamental solutions. • The SIF of nonhomogeneity HTS decrease with nonhomogeneity parameters increasing. • The greater the applied field, the higher the SIF value. • The greater critical current density of the nonhomogeneity HTS is, the smaller values of the SIF. - Abstract: To analyze the fracture problem of the nonhomogeneous high temperature superconductor (HTS) slab under electromagnetic force, we derive the real fundamental solutions based on eigenvalue and eigenvector analyses. The superconductor E-J constitutive law is characterized by the Bean model where the critical current density is independent of the flux density. Fracture analysis is performed by the methods of singular integral equations which are solved numerically by Lobatto–Chybeshev collocation method. Numerical results of the stress intensity factor (SIF) are obtained. Moreover, the crack opening displacement (COD) can be obtained by numerical integration dislocation density functions. The effects of the thickness ratio, HTS material nonhomogeneous parameters, applied magnetic field and critical current density on SIF and COD are discussed. The present work could theoretically provide quantitative predictions of the fracture mechanism of the nonhomogeneous HTS.

  2. Characteristic and magnetic field analysis of a high temperature superconductor axial-flux coreless induction maglev motor

    Science.gov (United States)

    Wei, Qin; Yu, Fan; Jin, Fang; Shuo, Li; Guoguo, Li; Gang, Lv

    2012-04-01

    A new high temperature superconductor axial-flux coreless maglev motor (HTS AFIM) is proposed, of which the primary windings are made of HTS tapes and the secondary is a non-magnetic conductor. The main works of this paper are the magnetic-field computation and characteristics analysis of HTS AFIM. For the first one, the reduction of magnetic fields near outer and inner radius of the HTS AFIM is solved by introducing the sub-loop electro-magnetic model along the radial position. For the second one, the AC losses of HTS coils are calculated. The relationships between the device's characteristics and device parameters are presented, and the results indicate that under certain frequency and current levitation device can output enough lift force. The conclusions are verified by finite element calculations.

  3. Characteristic and magnetic field analysis of a high temperature superconductor axial-flux coreless induction maglev motor.

    Science.gov (United States)

    Wei, Qin; Yu, Fan; Jin, Fang; Shuo, Li; Guoguo, Li; Gang, Lv

    2012-04-01

    A new high temperature superconductor axial-flux coreless maglev motor (HTS AFIM) is proposed, of which the primary windings are made of HTS tapes and the secondary is a non-magnetic conductor. The main works of this paper are the magnetic-field computation and characteristics analysis of HTS AFIM. For the first one, the reduction of magnetic fields near outer and inner radius of the HTS AFIM is solved by introducing the sub-loop electro-magnetic model along the radial position. For the second one, the AC losses of HTS coils are calculated. The relationships between the device's characteristics and device parameters are presented, and the results indicate that under certain frequency and current levitation device can output enough lift force. The conclusions are verified by finite element calculations.

  4. Fracture analysis of a transversely isotropic high temperature superconductor strip based on real fundamental solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhiwen, E-mail: gaozhw@lzu.edu.cn; Zhou, Youhe

    2015-04-15

    Highlights: • We studied fracture problem in HTS based on real fundamental solutions. • When the thickness of HTS strip increases the SIF decrease. • A higher applied field leads to a larger stress intensity factor. • The greater the critical current density is, the smaller values of the SIF is. - Abstract: Real fundamental solution for fracture problem of transversely isotropic high temperature superconductor (HTS) strip is obtained. The superconductor E–J constitutive law is characterized by the Bean model where the critical current density is independent of the flux density. Fracture analysis is performed by the methods of singular integral equations which are solved numerically by Gauss–Lobatto–Chybeshev (GSL) collocation method. To guarantee a satisfactory accuracy, the convergence behavior of the kernel function is investigated. Numerical results of fracture parameters are obtained and the effects of the geometric characteristics, applied magnetic field and critical current density on the stress intensity factors (SIF) are discussed.

  5. Fracture problem of a nonhomogeneous high temperature superconductor slab based on real fundamental solutions

    Science.gov (United States)

    Gao, Zhiwen; Zheng, Zhiye; Li, Xueyi

    2015-12-01

    To analyze the fracture problem of the nonhomogeneous high temperature superconductor (HTS) slab under electromagnetic force, we derive the real fundamental solutions based on eigenvalue and eigenvector analyses. The superconductor E-J constitutive law is characterized by the Bean model where the critical current density is independent of the flux density. Fracture analysis is performed by the methods of singular integral equations which are solved numerically by Lobatto-Chybeshev collocation method. Numerical results of the stress intensity factor (SIF) are obtained. Moreover, the crack opening displacement (COD) can be obtained by numerical integration dislocation density functions. The effects of the thickness ratio, HTS material nonhomogeneous parameters, applied magnetic field and critical current density on SIF and COD are discussed. The present work could theoretically provide quantitative predictions of the fracture mechanism of the nonhomogeneous HTS.

  6. Two-Dimensional Superconductor with a Giant Rashba Effect: One-Atom-Layer Tl-Pb Compound on Si(111)

    Science.gov (United States)

    Matetskiy, A. V.; Ichinokura, S.; Bondarenko, L. V.; Tupchaya, A. Y.; Gruznev, D. V.; Zotov, A. V.; Saranin, A. A.; Hobara, R.; Takayama, A.; Hasegawa, S.

    2015-10-01

    A one-atom-layer compound made of one monolayer of Tl and one-third monolayer of Pb on a Si(111) surface having √{3 }×√{3 } periodicity was found to exhibit a giant Rashba-type spin splitting of metallic surface-state bands together with two-dimensional superconducting transport properties. Temperature-dependent angle-resolved photoelectron spectroscopy revealed an enhanced electron-phonon coupling for one of the spin-split bands. In situ micro-four-point-probe conductivity measurements with and without magnetic field demonstrated that the (Tl, Pb)/Si(111) system transformed into the superconducting state at 2.25 K, followed by the Berezinskii-Kosterlitz-Thouless mechanism. The 2D Tl-Pb compound on Si(111) is believed to be the prototypical object for prospective studies of intriguing properties of the superconducting 2D system with lifted spin degeneracy, bearing in mind that its composition, atomic and electron band structures, and spin texture are already well established.

  7. Superconductor cable

    Science.gov (United States)

    Allais, Arnaud; Schmidt, Frank; Marzahn, Erik

    2010-05-04

    A superconductor cable is described, having a superconductive flexible cable core (1) , which is laid in a cryostat (2, 3, 4), in which the cable core (1) runs in the cryostat (2, 3, 4) in the form of a wave or helix at room temperature.

  8. Development of high temperature superconductors for magnetic field applications

    Energy Technology Data Exchange (ETDEWEB)

    Larbalestier, D.C.

    1991-12-31

    The key requirement for magnetic field applications of high temperature superconductor (HTS) materials is to have conductors with high transport critical current density available for magnet builders. After 3 or 4 years of being without any such object, conductor makers have had recent success in producing simple conductor prototypes. These have permitted the construction of simple HTS magnets having self fields exceeding 1 tesla at 4K. Thus the scientific feasibility of making powerful HTS magnets has been demonstrated. Attention to the technological aspects of making HTS conductors for magnets with strong flux pinning and reduced superconducting granularity is now sensible and attractive. However, extrinsic defects such as filament sausaging, cracking, misaligned grains and other perturbation to long range current flow must be controlled at a low level if the benefit of intrinsic improvements to the critical current density is to be maintained in the conductor form. Due to the great complexity of the HTS materials, there is sometimes confusion as to whether a given sample has an intrinsically or extrinsically limited critical current density. Systematic microstructure variation experiments and resistive transition analysis are shown to be particularly helpful in this phase of conductor development.

  9. Development of high temperature superconductors for magnetic field applications

    Energy Technology Data Exchange (ETDEWEB)

    Larbalestier, D.C.

    1991-01-01

    The key requirement for magnetic field applications of high temperature superconductor (HTS) materials is to have conductors with high transport critical current density available for magnet builders. After 3 or 4 years of being without any such object, conductor makers have had recent success in producing simple conductor prototypes. These have permitted the construction of simple HTS magnets having self fields exceeding 1 tesla at 4K. Thus the scientific feasibility of making powerful HTS magnets has been demonstrated. Attention to the technological aspects of making HTS conductors for magnets with strong flux pinning and reduced superconducting granularity is now sensible and attractive. However, extrinsic defects such as filament sausaging, cracking, misaligned grains and other perturbation to long range current flow must be controlled at a low level if the benefit of intrinsic improvements to the critical current density is to be maintained in the conductor form. Due to the great complexity of the HTS materials, there is sometimes confusion as to whether a given sample has an intrinsically or extrinsically limited critical current density. Systematic microstructure variation experiments and resistive transition analysis are shown to be particularly helpful in this phase of conductor development.

  10. Characterization of high-current, high-temperature superconductor current lead elements

    Energy Technology Data Exchange (ETDEWEB)

    Niemann, R.C.; Evans, D.J.; Fisher, B.L. [Argonne National Lab., IL (United States); Brockenborough, W.E.; Roberts, P.R.; Rodenbush, A.J. [American Superconductor Corp., Westborough, MA (United States)

    1996-08-01

    The refrigeration loads of current leads for superconducting magnets can be significantly reduced by using high-temperature superconductor (HTS) leads. An HTS conductor type that is well suited for this application is a laminated sintered stack of HTS powder-in-tube (PIT) tapes. The superconducting elements are normally characterized by their manufacturer by measuring critical currents at 77 K in self field. Additional characterization, which correlates electrical performance at 77 K and at lower temperatures with applied magnetic fields, provides the current lead designer and conductor element manufacturer with critical information. For HTS conductor elements comprising a laminated and sintered stack of Bi-2223 PIT tapes having an alloyed Ag sheath, this characterization uses variable applied fields and operating temperatures.

  11. Evaluation of the invasion heat for the HTS current lead using YBCO

    Science.gov (United States)

    Endoh, R.; Kato, H.; Izumi, T.; Shiohara, Y.

    2003-10-01

    Current leads using high- TC superconductors (HTS current leads) are one of cryogenic key devices to assemble compact superconducting magnets such as applied for maglev trains etc. It is essential to evaluate effective thermal conductance through a HTS current lead package together with evaluating Joule heat and critical current for efficient design that has high current capacity and low heat invasion. We have designed the 500 A class HTS current lead package using a YBCO rod whose size is ∅ 3 × 30 mm, and developed an apparatus to measure its heat invasion. Temperature drop as a function of heat flow between the two ends of the package was measured by a conventional steady heat flow method. The quantity of heat invasion of the package under typical practical conditions, from 80 K hot end to 20 K cold end, was 163 mW. This value was simulated to the total value of 158 mW by counting contributions of all the component materials.

  12. HTS-FCL EMTDC model considering nonlinear characteristics on fault current and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Jae-Young; Lee, Seung-Ryul [Korea Electrotechnology Research Institute (Korea, Republic of)

    2010-06-01

    One of the most serious problems of the KEPCO system is a higher fault current than the CB(Circuit breaker's SCC (Short Circuit Capacity). There are so many alternatives to reduce the higher fault current, such as the isolation of bus ties, enhancement of the CB's SCC, and the application of HVDC-BTB (Back to Back) or FCL (fault current limiter). However, these alternatives have drawbacks from the viewpoint of system stability and cost. As superconductivity technology has been developed, the resistive type (R-type) HTS-FCL (High Temperature Superconductor Fault Current Limiter) offers one of the important alternatives in terms of power loss and cost reduction in solving the fault current problem. To evaluate the accurate transient performance of R-type HTS-FCL, it is necessary for the dynamic simulation model to consider transient characteristics during the quenching and the recovery state. Against this background, this paper presents the new HTS-FCL EMTDC (Electro-Magnetic Transients including Direct Current) model considering the nonlinear characteristics on fault current and temperature.

  13. HTS-FCL EMTDC model considering nonlinear characteristics on fault current and temperature

    Science.gov (United States)

    Yoon, Jae-Young; Lee, Seung-Ryul

    2010-06-01

    One of the most serious problems of the KEPCO system is a higher fault current than the CB(Circuit breaker's SCC (Short Circuit Capacity). There are so many alternatives to reduce the higher fault current, such as the isolation of bus ties, enhancement of the CB's SCC, and the application of HVDC-BTB (Back to Back) or FCL (fault current limiter). However, these alternatives have drawbacks from the viewpoint of system stability and cost. As superconductivity technology has been developed, the resistive type (R-type) HTS-FCL (High Temperature Superconductor Fault Current Limiter) offers one of the important alternatives in terms of power loss and cost reduction in solving the fault current problem. To evaluate the accurate transient performance of R-type HTS-FCL, it is necessary for the dynamic simulation model to consider transient characteristics during the quenching and the recovery state. Against this background, this paper presents the new HTS-FCL EMTDC (Electro-Magnetic Transients including Direct Current) model considering the nonlinear characteristics on fault current and temperature.

  14. Testing of machine wound second generation HTS tape Vacuum Pressure Impregnated coils

    Science.gov (United States)

    Swaffield, D.; Lewis, C.; Eugene, J.; Ingles, M.; Peach, D.

    2014-05-01

    Delamination of second generation (2G) High Temperature Superconducting (HTS) tapes has previously been reported when using resin based insulation systems for wound coils. One proposed root cause is the differential thermal contraction between the coil former and the resin encapsulated coil turns resulting in the tape c-axis tensile stress being exceeded. Importantly, delamination results in unacceptable degradation of the superconductor critical current level. To mitigate the delamination risk and prove winding, jointing and Vacuum Pressure Impregnation (VPI) processes in the production of coils for superconducting rotating machines at GE Power Conversion two scaled trial coils have been wound and extensively tested. The coils are wound from 12mm wide 2G HTS tape supplied by AMSC onto stainless steel 'racetrack' coil formers. The coils are wound in two layers which include both in-line and layer-layer joints subject to in-process test. The resin insulation system chosen is VPI and oven cured. Tests included; insulation resistance, repeat quench and recovery of the superconductor, heat runs and measurement of n-value, before and after multiple thermal cycling between ambient and 35 Kelvin. No degradation of coil performance is evidenced.

  15. Electrical transport anisotropy of uniaxial polycrystalline samples and the effective medium approximation: An application to HTS

    Science.gov (United States)

    Cruz-García, A.; Muné, P.

    2016-08-01

    In this paper we have applied the effective medium approximation (EMA) to a polycrystalline sample made up of uniaxial crystallites with similar behavior to the high critical temperature superconductors (HTS) at the normal state (σab ≫ σc). As a result the dependence of the anisotropy parameter at the level of the sample, μ =σx /σz , on orientation probability of the grains' a-axes along a certain preferential direction, γxa is obtained. The intrinsic and shape anisotropy parameters of the crystallites constitute input data. In addition, the dependence of the orientation factor, f, which has been introduced in current models on the transport properties of HTS, is calculated as a function of γxa. These results offer a tool to interpret electrical transport measurements at normal state in granular uniaxial superconducting materials with certain texture degree, by means of the correlation between microstructure and electrical transport properties. Moreover, the comparison between the model and some experimental data suggests the presence of intragranular planar defects in the polycrystalline superconductors. They may affect the measurement of paracoherent resistivity and consequently the determination of f mainly in Bi based samples.

  16. HTS Transmission Cable System for installation in the Long Island Power Grid

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Frank [American Superconductor Corporation, Devens, MA (United States); Durand, Fabien [American Superconductor Corporation, Devens, MA (United States); Maguire, James [American Superconductor Corporation, Devens, MA (United States)

    2015-10-05

    Department of Energy (DOE) Award DE-FC26-07NT43240 was issued on October 1, 2007. Referred to as LIPA2, the principal objectives of the project were to develop key components required to deploy and demonstrate second-generation (2G) high temperature superconductor (HTS) cables in a 600 meter (2000 feet) underground segment of a 138kV three-phase transmission circuit of the Long Island Power Authority (LIPA) power grid. A previous effort under DOE Award DE-FC36-03GO13032 (referred to as LIPA1) resulted in installation (and subsequent successful operation) of first-generation (1G) HTS cables at the LIPA site. As with LIPA1, American Superconductor (AMSC) led the effort for LIPA2 and was responsible for overall management of the project and producing sufficient 2G wire to fabricate the required cable. Nexans' tasks included design/manufacture/installation of the cable, joint (splice), cable terminations and field repairable cryostat; while work by Air Liquide involved engineering and installation support for the refrigeration system modifications.

  17. Search for unconventional superconductors among the YTE2Si2 compounds (TE = Cr, Co, Ni, Rh, Pd, Pt).

    Science.gov (United States)

    Pikul, Adam P; Samsel-Czekala, Malgorzata; Chajewski, Grzegorz; Romanova, Tetiana; Hackemer, Alicja; Gorzelniak, Roman; Wiśniewski, Piotr; Kaczorowski, Dariusz

    2017-03-21

    Motivated by the recent discovery of exotic superconductivity in YFe2Ge2 we undertook reinvestigation of formation and physical properties of yttrium-based 1:2:2 silicides. Here we report on syntheses and crystal structures of the YTE2Si2 compounds with TE = Cr, Co, Ni, Rh, Pd, and Pt, and their low-temperature physical properties measurements, supplemented by results of fully relativistic FPLO band structure calculations. We confirm that most of the members of that family crystallize in a tetragonal ThCr2Si2-type structure (space group I4/mmm) and have three-dimensional Fermi surface, while only one of them (YPt2Si2) forms with a closely-related primitive CaBe2Ge2-type unit cell (space group P4/nmm) and possess quasi-two-dimensional Fermi surface sheets. Physical measurements indicated that BCS-like superconductivity is observed only in YPt2Si2 (Tc = 1.54 K) and YPd2Si2 (Tc = 0.43 K), while no superconducting phase transition was found in other systems at least down to 0.35 K. Thermal analysis showed no polymorphism in both superconducting phases. No clear relation between the superconductivity and the crystal structure (and dimensionality of the Fermi surface) was observed.

  18. H-formulation for simulating levitation forces acting on HTS bulks and stacks of 2G coated conductors

    Science.gov (United States)

    Sass, F.; Sotelo, G. G.; Junior, R. de Andrade; Sirois, Frédéric

    2015-12-01

    Several techniques to model high temperature superconductors (HTSs) are used throughout the world. At the same time, the use of superconductors in transportation and magnetic bearings promises an increase in energy efficiency. However, the most widespread simulation technique in the literature, the H-formulation, has not yet been used to simulate superconducting levitation. The goal of this work is to present solutions for the challenges concerning the use of the H-formulation to predict the behavior of superconducting levitators built either with YBCO bulks or stacks of 2G wires. It is worth mentioning the originality of replacing bulks with HTS stacks in this application. In our simulation methodology, the movement between the HTS and the permanent magnet was avoided by restricting the simulation domain to the HTS itself, which can be done by applying appropriate boundary conditions and analytical expressions for the source field. Commercial finite element software was used for the sake of ease of implementation. Simulation results were compared with experimental data, showing good agreement. We conclude that the H-formulation is suitable for problems involving moving objects and is a good alternative to other approaches for simulating superconducting magnetic bearings.

  19. Iron pnictide superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Tegel, Marcus Christian

    2011-03-22

    The scope of this dissertation therefore has not only been the synthesis of various new superconducting and non-superconducting iron pnictides of several structural families but also their in-depth crystallographic and physical characterisation. In Chapters 3 - 6, the family of the ZrCuSiAs-type (1111) compounds is subject of discussion. The solid solution series La(Co{sub x}Fe{sub 1-x})PO is analysed regarding magnetic and superconducting properties and the new compounds EuMnPF and REZnPO, as well as the new superconductor parent compound SrFeAsF are presented. Chapters 7 - 9 are dedicated to the new iron arsenide superconductors of the ThCr{sub 2}Si{sub 2}-type (122 family). Therein, also the discovery of the first superconductor in this structural family, Ba{sub 0.6}K{sub 0.4}Fe{sub 2}As{sub 2}, is unveiled. A detailed examination of the complete solid solution series (Ba{sub 1-x}K{sub x})Fe{sub 2}As{sub 2} is presented. Moreover, the crystallographic phase transitions of the closely related compounds SrFe{sub 2}As{sub 2} and EuFe{sub 2}As{sub 2} are characterised and the superconductors Sr{sub 1-x}K{sub x}Fe{sub 2}As{sub 2} and Ca{sub 1-x}Na{sub x}Fe{sub 2}As{sub 2} are examined for magnetic and phononic excitations. In Chapter 10, the redetermined crystal structure of the superconductor Fe(Se{sub 1-x}Te{sub x}) (11-type) is presented from a chemist's point of view. Chapters 11 - 14 look into the superconducting and non-superconducting iron arsenides of more complex structural families (32522-type and 21311-type). Therein, crystallographic and magnetic details of Sr{sub 3}Sc{sub 2}O{sub 5}Fe{sub 2}As{sub 2} are presented and Ba{sub 2}ScO{sub 3}FeAs and Sr{sub 2}CrO{sub 3}FeAs, the first two members of the new 21311-type are portrayed. Sr{sub 2}CrO{sub 3}FeAs is looked at in close detail with various methods, so e.g. the spin structure of the magnetically ordered compound is solved and a possible reason for the absence of superconductivity in this compound

  20. Modeling AC ripple currents in HTS coated conductors by integral equations

    Science.gov (United States)

    Grilli, Francesco; Xu, Zhihan

    2016-12-01

    In several HTS applications, the superconducting tapes experience the simultaneous presence of DC and AC excitations. For example in high-current DC cables, where the transport current is not perfectly constant, but it exhibits some ripples at different frequencies introduced by the rectification process (AC-DC conversion). These ripples give rise to dissipation, whose magnitude and possible influence on the device's cooling requirements need to be evaluated. Here we report a study of the AC losses in a HTS coated conductor subjected to DC currents and AC ripples simultaneously. The modeling approach is based on an integral equation method for thin superconductors: the superconducting tape is modeled as a 1-D object with a non-linear resistivity, which includes the dependence of the critical current density Jc on the magnetic field. The model, implemented in a commercial finite-element program, runs very fast (the simulation of one AC cycle typically takes a few seconds on standard desktop workstation): this allows simulating a large number of cycles and estimating when the AC ripple losses stabilize to a constant value. The model is used to study the influence of the flux creep power index n on the stabilization speed and on the AC loss values, as well as the effect of using a field-dependent Jc instead of a constant one. The simulations confirm that the dissipation level should not be a practical concern in HTS DC cables. At the same time, however, they reveal a strong dependence of the results upon the power index n and the form of Jc , which spurs the question whether the power-law is the most suitable description of the superconductor's electrical behavior for this kind of analysis.

  1. A HTS dipole insert coil constructed

    CERN Document Server

    Ballarino, A; Rey, J M; Stenvall, A; Sorbi, M; Tixador, P

    2013-01-01

    This report is the deliverable report 7.4.1 “A HTS dipole insert coil constructed“. The report has three parts: “Design report for the HTS dipole insert”, “One insert pancake prototype coil constructed with the setup for a high field test”, and “All insert components ordered”. The three report parts show that, although the insert construction will be only completed by end 2013, all elements are present for a successful completion and that, given the important investments done by the participants, there is a full commitment of all of them to finish the project

  2. ARQiv-HTS, a versatile whole-organism screening platform enabling in vivo drug discovery at high-throughput rates.

    Science.gov (United States)

    White, David T; Eroglu, Arife Unal; Wang, Guohua; Zhang, Liyun; Sengupta, Sumitra; Ding, Ding; Rajpurohit, Surendra K; Walker, Steven L; Ji, Hongkai; Qian, Jiang; Mumm, Jeff S

    2016-12-01

    The zebrafish has emerged as an important model for whole-organism small-molecule screening. However, most zebrafish-based chemical screens have achieved only mid-throughput rates. Here we describe a versatile whole-organism drug discovery platform that can achieve true high-throughput screening (HTS) capacities. This system combines our automated reporter quantification in vivo (ARQiv) system with customized robotics, and is termed 'ARQiv-HTS'. We detail the process of establishing and implementing ARQiv-HTS: (i) assay design and optimization, (ii) calculation of sample size and hit criteria, (iii) large-scale egg production, (iv) automated compound titration, (v) dispensing of embryos into microtiter plates, and (vi) reporter quantification. We also outline what we see as best practice strategies for leveraging the power of ARQiv-HTS for zebrafish-based drug discovery, and address technical challenges of applying zebrafish to large-scale chemical screens. Finally, we provide a detailed protocol for a recently completed inaugural ARQiv-HTS effort, which involved the identification of compounds that elevate insulin reporter activity. Compounds that increased the number of insulin-producing pancreatic beta cells represent potential new therapeutics for diabetic patients. For this effort, individual screening sessions took 1 week to conclude, and sessions were performed iteratively approximately every other day to increase throughput. At the conclusion of the screen, more than a half million drug-treated larvae had been evaluated. Beyond this initial example, however, the ARQiv-HTS platform is adaptable to almost any reporter-based assay designed to evaluate the effects of chemical compounds in living small-animal models. ARQiv-HTS thus enables large-scale whole-organism drug discovery for a variety of model species and from numerous disease-oriented perspectives.

  3. Superconductor Dynamics

    CERN Document Server

    Gömöry, F

    2014-01-01

    Superconductors used in magnet technology could carry extreme currents because of their ability to keep the magnetic flux motionless. The dynamics of the magnetic flux interaction with superconductors is controlled by this property. The cases of electrical transport in a round wire and the magnetization of wires of various shapes (circular, elliptical, plate) in an external magnetic field are analysed. Resistance to the magnetic field penetration means that the field produced by the superconducting magnet is no longer proportional to the supplied current. It also leads to a dissipation of electromagnetic energy. In conductors with unequal transverse dimensions, such as flat cables, the orientation with respect to the magnetic field plays an essential role. A reduction of magnetization currents can be achieved by splitting the core of a superconducting wire into fine filaments; however, new kinds of electrical currents that couple the filaments consequently appear. Basic formulas allowing qualitative analyses ...

  4. Chiral superconductors.

    Science.gov (United States)

    Kallin, Catherine; Berlinsky, John

    2016-05-01

    Chiral superconductivity is a striking quantum phenomenon in which an unconventional superconductor spontaneously develops an angular momentum and lowers its free energy by eliminating nodes in the gap. It is a topologically non-trivial state and, as such, exhibits distinctive topological modes at surfaces and defects. In this paper we discuss the current theory and experimental results on chiral superconductors, focusing on two of the best-studied systems, Sr2RuO4, which is thought to be a chiral triplet p-wave superconductor, and UPt3, which has two low-temperature superconducting phases (in zero magnetic field), the lower of which is believed to be chiral triplet f-wave. Other systems that may exhibit chiral superconductivity are also discussed. Key signatures of chiral superconductivity are surface currents and chiral Majorana modes, Majorana states in vortex cores, and the possibility of half-flux quantum vortices in the case of triplet pairing. Experimental evidence for chiral superconductivity from μSR, NMR, strain, polar Kerr effect and Josephson tunneling experiments are discussed.

  5. 'Leak Current' correction for critical current measurement of no-insulation HTS coil

    Energy Technology Data Exchange (ETDEWEB)

    Song, Jung Bin [Laboratoire National des Champs Magnétiques Intenses, CNRS, Grenoble (France); Hahn, Seung Yong [Dept. of Electrical and Computer Engineering, Seoul National University, Seoul (Korea, Republic of)

    2017-06-15

    Discrepancy between a power supply current and an actual “spiral” coil current makes the conventional 4-probe measurement of a critical current (I{sub c}) of a no-insulation (NI) high temperature superconductor (HTS) coil inaccurate and time-consuming. This paper presents a fast and accurate approach for I{sub c} measurement of NI HTS coils. With an NI HTS coil energized at a constant ramping rate, a complete analytic expression for the spiral coil current was obtained from a first-order partial differential equation that derived from an equivalent circuit model of the NI coil. From the analytic solution, both spiral coil current and radial leak current can be obtained simultaneously, which enables fast and accurate measurement of the NI coil I{sub c}. To verify the proposed approach, an NI double-pancake (DP) coil, wound with GdBCO tapes of 6 mm × 0.1 mm, was constructed and its Ic was repeatedly measured with various ramping rates in a bath of liquid nitrogen at 77 K. The measured results agreed well with the calculated ones, which validates the proposed approach to measure I{sub c} of an NI HTS coil.

  6. Engineering of second generation HTS coated conductor architecture to enhance the normal zone propagation velocity in various operating conditions

    Science.gov (United States)

    Lacroix, C.; Sirois, F.; Fournier Lupien, J.-H.

    2017-06-01

    The effects of operating conditions, critical current and stabilizer geometry on the normal zone propagation velocity (NZPV) of second generation (2G) high-temperature superconductor (HTS) coated conductors (CCs) are investigated using finite element simulations. The NZPV of tapes with a low interfacial resistance between the HTS and stabilizer layers are first compared with tapes with a current flow diverter (CFD) architecture. Our results indicates that the CFD concept increases the NZPV for the whole range of operating temperatures investigated (10-77 K). In particular, for an operating temperature of 77 K and an operating current of 0.9I c, our numerical results indicate that the NZPV of a 2G HTS CC with a CFD architecture and a 2 μm thick stabilizer layer could reach a value of 50 m s-1. Furthermore, numerical simulations realized on the effect of the stabilizer geometry on the NZPV of 2G HTS CCs revealed that putting most of the stabilizer on the substrate side can enhance the NZPV by a factor of 7 or more, even for tape with thick stabilizer (20 μm or more). This is particularly promising for improving quench detection in applications requiring a thick stabilizer such as superconducting coils.

  7. Conceptual design of a 20-kA current lead using forced-flow cooling and Ag-alloy-sheathed Bi-2223 high-temperature superconductors

    Science.gov (United States)

    Heller, Reinhard; Hull, John R.

    High-temperature superconductors (HTS's), consisting of Bi-2223 HTS tapes sheathed with Ag alloys are proposed for a 20-kA current lead for the planned stellarator WENDELSTEIN 7-X. Forced-flow He cooling is used, and 4-K He cooling of the whole lead as well as 60-K He cooling of the copper part of the lead, is discussed. Power consumption and behavior in case of loss of He flow are given.

  8. Vortices in high-performance high-temperature superconductors

    Science.gov (United States)

    Kwok, Wai-Kwong; Welp, Ulrich; Glatz, Andreas; Koshelev, Alexei E.; Kihlstrom, Karen J.; Crabtree, George W.

    2016-11-01

    The behavior of vortex matter in high-temperature superconductors (HTS) controls the entire electromagnetic response of the material, including its current carrying capacity. Here, we review the basic concepts of vortex pinning and its application to a complex mixed pinning landscape to enhance the critical current and to reduce its anisotropy. We focus on recent scientific advances that have resulted in large enhancements of the in-field critical current in state-of-the-art second generation (2G) YBCO coated conductors and on the prospect of an isotropic, high-critical current superconductor in the iron-based superconductors. Lastly, we discuss an emerging new paradigm of critical current by design—a drive to achieve a quantitative correlation between the observed critical current density and mesoscale mixed pinning landscapes by using realistic input parameters in an innovative and powerful large-scale time dependent Ginzburg-Landau approach to simulating vortex dynamics.

  9. Vortices in high-performance high-temperature superconductors.

    Science.gov (United States)

    Kwok, Wai-Kwong; Welp, Ulrich; Glatz, Andreas; Koshelev, Alexei E; Kihlstrom, Karen J; Crabtree, George W

    2016-11-01

    The behavior of vortex matter in high-temperature superconductors (HTS) controls the entire electromagnetic response of the material, including its current carrying capacity. Here, we review the basic concepts of vortex pinning and its application to a complex mixed pinning landscape to enhance the critical current and to reduce its anisotropy. We focus on recent scientific advances that have resulted in large enhancements of the in-field critical current in state-of-the-art second generation (2G) YBCO coated conductors and on the prospect of an isotropic, high-critical current superconductor in the iron-based superconductors. Lastly, we discuss an emerging new paradigm of critical current by design-a drive to achieve a quantitative correlation between the observed critical current density and mesoscale mixed pinning landscapes by using realistic input parameters in an innovative and powerful large-scale time dependent Ginzburg-Landau approach to simulating vortex dynamics.

  10. Current distribution among layers of single phase HTS cable conductor

    Science.gov (United States)

    Zheng, Y. B.; Wang, Y. S.; Pi, W.; Ju, P.; Wang, Y. S.

    2014-12-01

    High temperature superconducting (HTS) power cable shows high application prospect in modern power transmission, as it is superior over conventional transmission lines in high engineering current density and environmental friendliness. Its configuration is generally composed of several HTS layers designed with the principle of uniform current distribution, but there are few experimental results to verify the distribution. In this paper, a HTS cable model was designed based on the principle of uniform current, and the current distributions among layers in an HTS cable model were measured by Rogowski coils. The results provide an important basis for design of multi-layer HTS cable.

  11. Study - Radiation Shielding Effectiveness of the Prototyped High Temperature Superconductivity (HTS) 'Artificial' Magnetosphere for Deep Space Missions

    Science.gov (United States)

    Denkins, Pamela

    2010-01-01

    The high temperature superconductor (HTS) is being used to develop the magnets for the Variable Specific Impulse Magneto-plasma Rocket (VASIMR ) propulsion system and may provide lightweight magnetic radiation shielding to protect spacecraft crews from radiation caused by GCR and SPEs on missions to Mars. A study is being planned to assess the radiation shielding effectiveness of the artificial magnetosphere produced by the HTS magnet. VASIMR is an advanced technology propulsion engine which is being touted as enabling one way transit to Mars in 90 days or less. This is extremely important to NASA. This technology would enable a significant reduction in the number of days in transit to and from Mars and significantly reduce the astronauts exposure to a major threat - high energy particles from solar storms and GCR during long term deep space missions. This paper summarizes the plans for the study and the subsequent testing of the VASIMR technology onboard the ISS slated for 2013.

  12. A study on the required performance of a 2G HTS wire for HTS wind power generators

    Science.gov (United States)

    Sung, Hae-Jin; Park, Minwon; Go, Byeong-Soo; Yu, In-Keun

    2016-05-01

    YBCO or REBCO coated conductor (2G) materials are developed for their superior performance at high magnetic field and temperature. Power system applications based on high temperature superconducting (HTS) 2G wire technology are attracting attention, including large-scale wind power generators. In particular, to solve problems associated with the foundations and mechanical structure of offshore wind turbines, due to the large diameter and heavy weight of the generator, an HTS generator is suggested as one of the key technologies. Many researchers have tried to develop feasible large-scale HTS wind power generator technologies. In this paper, a study on the required performance of a 2G HTS wire for large-scale wind power generators is discussed. A 12 MW class large-scale wind turbine and an HTS generator are designed using 2G HTS wire. The total length of the 2G HTS wire for the 12 MW HTS generator is estimated, and the essential prerequisites of the 2G HTS wire based generator are described. The magnetic field distributions of a pole module are illustrated, and the mechanical stress and strain of the pole module are analysed. Finally, a reasonable price for 2G HTS wire for commercialization of the HTS generator is suggested, reflecting the results of electromagnetic and mechanical analyses of the generator.

  13. Design of cryostat for testing high-Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Ho Myung; Baik, Joun Hoon; Lee, Hoon; Kim, Young Kwon; Park, Jeong Soo; Song, Seung Jae [Hongik University, Seoul (Korea, Republic of)

    1997-07-01

    This project is proposed to develop several design techniques concerning the gas-cooled or the refrigerator-cooled cryostats to test the HTS at temperature ranges between 20 K and 100 K. (1) It is shown by a numerical analysis that the thermal stability of HTS in a gas-cooled cryostat is satisfactory, mainly because of large heat capacity. The feasibility of the gas-cooled cryostat is demonstrated after the cooling load calculation, the selection of the cryocooler, and the detailed design and fabrication. It is also found that the current leads in the gas-cooled cryostat increases the cooling load but can make the cool-down time shorter to a considerable degree. (2) The thermal stability and the cooling load of HTS in a refrigerator-cooled cryostat do not differ much from those in a gas-cooled cryostat. On the other hand, it has been known that the thermal switches and the soft-contact materials in the refrigerator-superconductor interface are necessary to shorten the coo-down time and to provide a flexibility in the configuration of cryostat. Various shapes and designs are demonstrated for the refrigerator-cooled cryostat. (3) Binary current leads are indispensable in a refrigerator-cooled cryostat. The current lead is a series combination of a normal metal at warm side and a HTS at cold side. It is shown that the optimal diameter-length relation exits for the minimum refrigeration work. It is also found that the refrigerator work decreases as the length of HTS increases. For a given length of HTS, there is an optimal cross-sectional area and it increases with the length. 54 refs., 9 tabs., 56 figs. (author)

  14. Numerical analysis and finite element modelling of an HTS synchronous motor

    Energy Technology Data Exchange (ETDEWEB)

    Ainslie, M.D., E-mail: mda36@cam.ac.u [University of Cambridge, Department of Electrical Engineering (Division B), CAPE Building, 9 JJ Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Jiang, Y.; Xian, W.; Hong, Z.; Yuan, W.; Pei, R.; Flack, T.J.; Coombs, T.A. [University of Cambridge, Department of Electrical Engineering (Division B), CAPE Building, 9 JJ Thomson Avenue, Cambridge CB3 0FA (United Kingdom)

    2010-11-01

    This paper investigates the electromagnetic properties of high-temperature superconductors with a particular focus on the AC loss in coils made from YBCO superconductors. The numerical analysis and finite element modelling of the YBCO superconductors used in Cambridge's superconducting permanent magnet synchronous motor currently in development is described. The stack of tapes in the superconducting coils is modelled using the direct H formulation, a B-dependent critical current density and a bulk approximation. Magnetic boundary conditions for this model are derived from a 2D finite element method (FEM) motor model. The combination of these models allows the total AC loss (combined transport and magnetisation losses) in the HTS coils used in an all-superconducting machine design to be estimated. The raw AC loss figures are compared to the output power of the motor for two test cases, and it is found that the AC loss contributes significantly to the total loss and therefore efficiency. An experimental rig is also described, which has been built in order to test the electromagnetic properties and performance of the motor. It is explained how this rig will be used to investigate the magnetisation of the rotor and carry out AC loss measurements on the stator coils.

  15. Magnetic Signals of High-Temperature Superconductor Bulk During the Levitation Force Measurement Process

    Science.gov (United States)

    Huang, Huan; Zheng, Jun; Qian, Nan; Che, Tong; Zheng, Botian; Jin, Liwei; Deng, Zigang

    2017-05-01

    In order to study the commonly neglected magnetic field information in the course of levitation force measurement process in a superconducting maglev system, a multipoint magnetic field measurement platform was employed to acquire magnetic signals of a bulk high-Tc superconductor on both the top and the bottom surface. Working conditions including field cooling (FC) and zero field cooling were investigated for these vertical down and up motions above a permanent magnet guideway performed on a HTS maglev measurement system. We have discussed the magnetic flux variation process based on the Bean model. A magnetic hysteresis effect similar to the levitation force hysteresis loop of the bulk superconductor was displayed and analyzed in this paper. What is more valuable, there exists some available magnetic flux on the top surface of the bulk superconductor, and the proportion is as high as 62.42% in the FC condition, which provides an experimental hint to design the superconductor bulk and the applied field for practical use in a more efficient way. In particular, this work reveals real-time magnetic flux variation of the bulk superconductor in the levitation application, which is the other important information in contrast to the macroscopic levitation and guidance force investigations in previous studies, and it enriches the existing research methods. The results are significant for understanding the magnetic characteristic of superconductors, and they can contribute to optimize the present HTS maglev system design.

  16. Magnetic Signals of High-Temperature Superconductor Bulk During the Levitation Force Measurement Process

    Science.gov (United States)

    Huang, Huan; Zheng, Jun; Qian, Nan; Che, Tong; Zheng, Botian; Jin, Liwei; Deng, Zigang

    2017-02-01

    In order to study the commonly neglected magnetic field information in the course of levitation force measurement process in a superconducting maglev system, a multipoint magnetic field measurement platform was employed to acquire magnetic signals of a bulk high-Tc superconductor on both the top and the bottom surface. Working conditions including field cooling (FC) and zero field cooling were investigated for these vertical down and up motions above a permanent magnet guideway performed on a HTS maglev measurement system. We have discussed the magnetic flux variation process based on the Bean model. A magnetic hysteresis effect similar to the levitation force hysteresis loop of the bulk superconductor was displayed and analyzed in this paper. What is more valuable, there exists some available magnetic flux on the top surface of the bulk superconductor, and the proportion is as high as 62.42% in the FC condition, which provides an experimental hint to design the superconductor bulk and the applied field for practical use in a more efficient way. In particular, this work reveals real-time magnetic flux variation of the bulk superconductor in the levitation application, which is the other important information in contrast to the macroscopic levitation and guidance force investigations in previous studies, and it enriches the existing research methods. The results are significant for understanding the magnetic characteristic of superconductors, and they can contribute to optimize the present HTS maglev system design.

  17. Magnetic Forces Investigation of Bulk HTS over Permanent Magnetic Guideway under Different Lateral Offset with 3D-Model Numerical Method

    Directory of Open Access Journals (Sweden)

    Yiyun Lu

    2012-01-01

    Full Text Available Magnetic forces of a cylinder shape bulk high-temperature superconductor (HTS over a permanent magnet guideway (PMG are studied mathematically. One cylindrical bulk HTS with a diameter of 30 mm and 15 mm in height is used. Two types of PMG are employed for external magnetic fields consideration. The relationship of magnetic forces of bulk HTS under different lateral offsets over PMG is studied with 3D-model finite element method (FEM. The calculation results show that the maximum magnetic levitation force of bulk HTS over PMG is tightly related to the applied magnetic field distribution. For the symmetrical PMG, the maximum magnetic levitation force decreases linearly with the increase of lateral offset of the bulk sample. For the Halbach PMG, when lateral offset changes from 0 mm to 25 mm, the maximum magnetic levitation force increases with the increase of lateral offset of the bulk HTS. When the lateral offset exceeds the center of the Halbach by 25 mm, the maximum levitation force decreases rapidly with the increase of the lateral offset of the bulk sample.

  18. Design of a high-temperature superconductor current lead for electric utility SMES

    Science.gov (United States)

    Niemann, R. C.; Cha, Y. S.; Hull, J. R.; Rey, C. M.; Dixon, K. D.

    Current leads that rely on high-temperature superconductors (HTS's) to deliver power to devices operating at liquid helium temperature have the potential to reduce refrigeration requirements to levels significantly below those achievable with conventional leads. The design of HTS current leads suitable for use in near-term superconducting magnetic energy storage (SMES) is in progress. The SMES system has an 0.5 MWh energy capacity and a discharge power of 30 MW. Lead-design considerations include safety and reliability, electrical and thermal performance, structural integrity, manufacturability, and cost. Available details of the design, including materials, configuration, and performance predictions, are presented.

  19. A survey of possible passive antenna applications of high-temperature superconductors

    Science.gov (United States)

    Dinger, Robert J.; Bowling, Donald R.; Martin, Anna M.

    1991-09-01

    A survey of possible applications of high-temperature superconductors (HTSs) to antennas and antenna feed networks is presented. The frequency range considered is 1 MHz to 100 GHz. Three antenna application areas seem appropriate for HTS material: electrically small antennas and their matching networks; feed and matching networks for compact arrays with enhanced directive gain (superdirective arrays); and feed networks for millimeter-wave arrays. Preliminary experimental results are presented on YBaCuO and TBaCaCuO 500 MHz half-loop antennas that show an increase in radiation efficiency (compared with a copper antenna at the same temperature) by a factor of 5 for the HTS antennas.

  20. Ferromagnetic superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Huxley, Andrew D.

    2015-07-15

    Highlights: • Review of ferromagnetic superconductors. • Covers UGe{sub 2}, URhGe and UCoGe and briefly other materials. • The focus is on experimental data and the pairing mechanism. - Abstract: The co-existence of superconductivity and ferromagnetism is of potential interest for spintronics and high magnetic field applications as well as a fascinating fundamental state of matter. The recent focus of research is on a family of ferromagnetic superconductors that are superconducting well below their Curie temperature, the first example of which was discovered in 2000. Although there is a ‘standard’ theoretical model for how magnetic pairing might bring about such a state, why it has only been seen in a few materials that at first sight appear to be very closely related has yet to be fully explained. This review covers the current state of knowledge of the magnetic and superconducting properties of these materials with emphasis on how they conform and differ from the behaviour expected from the ‘standard’ model and from each other.

  1. Mobile conduction-cooled HTS SMES

    Science.gov (United States)

    Ren, L.; Tang, Y.; Li, J.; Shi, J.; Chen, L.; Guo, F.; Fang, J.; Wen, J.

    2010-11-01

    An immovable 35 kJ/7 kW high-Tc superconducting magnetic energy storage (HTS SMES) system had been developed in the Electric Power System Dynamic Simulation Laboratory, Huazhong University of Science and Technology in 2005. In order to adapt for on-site experimental conditions, the mechanical configuration of the magnet is reinforced and the SMES system is assembled in a special container to be freighted to the actual power system for the feasibility study on different applications at different sites. The mobile HTS SMES system had withstood various kinds of poor road surfaces and then arrived at the experimental site on August 18, 2009. In this paper, the reconstructed configuration and the shock absorption of the magnet are presented. The field test results show that the mobile SMES system can operate on the power network at different locations and suppress effectively power fluctuation of the generator terminal.

  2. Glass precursor approach to high-temperature superconductors

    Science.gov (United States)

    Bansal, Narottam P.

    1992-01-01

    The available studies on the synthesis of high T sub c superconductors (HTS) via the glass precursor approach were reviewed. Melts of the Bi-Sr-Ca-Cu-O system as well as those doped with oxides of some other elements (Pb, Al, V, Te, Nb, etc.) could be quenched into glasses which, on further heat treatments under appropriate conditions, crystallized into the superconducting phase(s). The nature of the HTS phase(s) formed depends on the annealing temperature, time, atmosphere, and the cooling rate and also on the glass composition. Long term annealing was needed to obtain a large fraction of the 110 K phase. The high T sub c phase did not crystallize out directly from the glass matrix, but was preceded by the precipitation of other phases. The 110 K HTS was produced at high temperatures by reaction between the phases formed at lower temperatures resulting in multiphase material. The presence of a glass former such as B2O3 was necessary for the Y-Ba-Cu-O melt to form a glass on fast cooling. A discontinuous YBa2Cu3O(7-delta) HTS phase crystallized out on heat treatment of this glass. Attempts to prepare Tl-Ba-Ca-Cu-O system in the glassy state were not successful.

  3. Oxide superconductor physics and nano-engineering II

    Energy Technology Data Exchange (ETDEWEB)

    Bozovic, I. [ed.] [Varian Research Center, Palo Alto, CA (United States); Pavuna, D. [ed.] [Swiss Federal Inst. of Tech., Lausanne (Switzerland)

    1996-12-31

    This book is organized as follows: In the first section the authors editors have grouped the papers dealing with physics and fundamental aspects of cuprate superconductors. Here, they have included also several theoretical papers that deal with the most basic issues related to the mechanism of HTS. Some of these ideas are clearly controversial and speculative, but they have decided to include them in line with the spirit of open-minded exchange of ideas that pervaded both conferences. In the second section the authors present the papers that deal with the synthesis of thin HTS films and their characterization. The third section contains papers related to artificial superlattices and multilayers and their properties. The fourth deals with intrinsic and artificial Josephson junctions. Finally, in the last section they present the articles dealing with novel HTS devices. Here, the progress with SFET, as reported by the IBM group, seems rather encouraging. Bold new ideas for other novel HTS devices are not lacking either. Separate abstracts were prepared for most papers in this book.

  4. AC Losses of Prototype HTS Transmission Cables

    Energy Technology Data Exchange (ETDEWEB)

    Demko, J.A.; Dresner, L.; Hughey, R.L.; Lue, J.W.; Olsen, S.K.; Sinha, U.; Tolbert, J.C.

    1998-09-13

    Since 1995 Southwire Company and Oak Ridge National Laboratory (ORNL) have jointly designed, built, and tested nine, l-m long, high temperature superconducting (HTS) transmission cable prototypes. This paper summarizes the AC loss measurements of five of the cables not reported elsewhere, and compares the losses with each other and with theory developed by Dresner. Losses were measured with both a calorimetric and an electrical technique. Because of the broad resistive transition of the HTS tapes, the cables can be operated stably beyond their critical currents. The AC losses were measured in this region as well as below critical currents. Dresner's theory takes into account the broad resistive transition of the HTS tapes and calculates the AC losses both below and above the critical current. The two sets of AC 10SS data agree with each other and with the theory quite welL In particular, at low currents of incomplete penetration, the loss data agree with the theoretical prediction of hysteresis loss based on only the outer two Iayers carrying the total current.

  5. First Russian long length HTS power cable

    Science.gov (United States)

    Volkov, Eduard P.; Vysotsky, Vitaly S.; Firsov, Valery P.

    2012-11-01

    The Russian R&D Program for superconducting power devices is underway, supported both by government and electric power companies. In this program R&D on HTS power cables is considered as most advanced and close to commercialization. In the framework of the program, several, heavily instrumented, 5 m cables have been tested following by the 30 m - 3 phase experimental power cable development and testing in 2008-2009. The latest achievement is development and testing of the first long length 3 × 200 m power cable with rating 1.5/2 kA-20 kV. In parallel with just the cable development the innovative cryogenic system has been developed as well for the cable cooling. The system is using neon as working substance and radial turbo-machines in refrigerator. Cooling power is up to ∼8 kW at 65 K, inter-maintenance time ∼30,000 h. The cryogenic pump with superconducting motor can be used to provide subcooled liquid nitrogen flow ∼0.1-1.5 kg/s at 0.1-2.5 MPa pressure. After extensive tests at special test facility, HTS power cable and cryogenic system are planning to be installed at some substation in Moscow utility grid. In this review some details about Russian HTS power application program, 200 m cable and cryogenic system designs and tests results are presented.

  6. Cost Effective Open Geometry HTS MRI System amended to BSCCO 2212 Wire for High Field Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Kennth Marken

    2006-08-11

    The original goal of this Phase II Superconductivity Partnership Initiative project was to build and operate a prototype Magnetic Resonance Imaging (MRI) system using high temperature superconductor (HTS) coils wound from continuously processed dip-coated BSCCO 2212 tape conductor. Using dip-coated tape, the plan was for MRI magnet coils to be wound to fit an established commercial open geometry, 0.2 Tesla permanent magnet system. New electronics and imaging software for a prototype higher field superconducting system would have added significantly to the cost. However, the use of the 0.2 T platform would allow the technical feasibility and the cost issues for HTS systems to be fully established. Also it would establish the energy efficiency and savings of HTS open MRI compared with resistive and permanent magnet systems. The commercial goal was an open geometry HTS MRI running at 0.5 T and 20 K. This low field open magnet was using resistive normal metal conductor and its heat loss was rather high around 15 kolwatts. It was expected that an HTS magnet would dissipate around 1 watt, significantly reduce power consumption. The SPI team assembled to achieve this goal was led by Oxford Instruments, Superconducting Technology (OST), who developed the method of producing commercial dip coated tape. Superconductive Components Inc. (SCI), a leading US supplier of HTS powders, supported the conductor optimization through powder optimization, scaling, and cost reduction. Oxford Magnet Technology (OMT), a joint venture between Oxford Instruments and Siemens and the world’s leading supplier of MRI magnet systems, was involved to design and build the HTS MRI magnet and cryogenics. Siemens Magnetic Resonance Division, a leading developer and supplier of complete MRI imaging systems, was expected to integrate the final system and perform imaging trials. The original MRI demonstration project was ended in July 2004 by mutual consent of Oxford Instruments and Siemens. Between

  7. Cost Effective Open Geometry HTS MRI System amended to BSCCO 2212 Wire for High Field Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Kennth Marken

    2006-08-11

    The original goal of this Phase II Superconductivity Partnership Initiative project was to build and operate a prototype Magnetic Resonance Imaging (MRI) system using high temperature superconductor (HTS) coils wound from continuously processed dip-coated BSCCO 2212 tape conductor. Using dip-coated tape, the plan was for MRI magnet coils to be wound to fit an established commercial open geometry, 0.2 Tesla permanent magnet system. New electronics and imaging software for a prototype higher field superconducting system would have added significantly to the cost. However, the use of the 0.2 T platform would allow the technical feasibility and the cost issues for HTS systems to be fully established. Also it would establish the energy efficiency and savings of HTS open MRI compared with resistive and permanent magnet systems. The commercial goal was an open geometry HTS MRI running at 0.5 T and 20 K. This low field open magnet was using resistive normal metal conductor and its heat loss was rather high around 15 kolwatts. It was expected that an HTS magnet would dissipate around 1 watt, significantly reduce power consumption. The SPI team assembled to achieve this goal was led by Oxford Instruments, Superconducting Technology (OST), who developed the method of producing commercial dip coated tape. Superconductive Components Inc. (SCI), a leading US supplier of HTS powders, supported the conductor optimization through powder optimization, scaling, and cost reduction. Oxford Magnet Technology (OMT), a joint venture between Oxford Instruments and Siemens and the world’s leading supplier of MRI magnet systems, was involved to design and build the HTS MRI magnet and cryogenics. Siemens Magnetic Resonance Division, a leading developer and supplier of complete MRI imaging systems, was expected to integrate the final system and perform imaging trials. The original MRI demonstration project was ended in July 2004 by mutual consent of Oxford Instruments and Siemens. Between

  8. Ferromagnetic superconductors

    Science.gov (United States)

    Huxley, Andrew D.

    2015-07-01

    The co-existence of superconductivity and ferromagnetism is of potential interest for spintronics and high magnetic field applications as well as a fascinating fundamental state of matter. The recent focus of research is on a family of ferromagnetic superconductors that are superconducting well below their Curie temperature, the first example of which was discovered in 2000. Although there is a 'standard' theoretical model for how magnetic pairing might bring about such a state, why it has only been seen in a few materials that at first sight appear to be very closely related has yet to be fully explained. This review covers the current state of knowledge of the magnetic and superconducting properties of these materials with emphasis on how they conform and differ from the behaviour expected from the 'standard' model and from each other.

  9. Superconductor cable

    Science.gov (United States)

    Allais, Arnaud; Schmidt, Frank (Langenhagen, DE

    2009-12-15

    A superconductor cable includes a superconductive cable core (1) and a cryostat (2) enclosing the same. The cable core (1) has a superconductive conductor (3), an insulation (4) surrounding the same and a shielding (5) surrounding the insulation (4). A layer (3b) of a dielectric or semiconducting material is applied to a central element (3a) formed from a normally conducting material as a strand or tube and a layer (3c) of at least one wire or strip of superconductive material is placed helically on top. The central element (3a) and the layer (3c) are connected to each other in an electrically conducting manner at the ends of the cable core (1).

  10. HTS in electric power applications, transformers

    Science.gov (United States)

    Hornfeldt, Sven P.

    With the discovery of the high temperature superconductors the prospect to find widespread applications of these conductors also in electric power applications grew very fast. The advantages that could be anticipated was reduced losses, reduced weight and volume plus less environmental impact. During the last five-six years techniques have been developed to produce long lengths of flexible conductors that can be used in cables or windings. Most manufacturers of high temperature superconductors concentrated on traditional DC applications. However, much larger markets will open up when good enough AC conductors become available for power applications. In 1994 ABB started a project aiming at a 630 kVA three-phase power transformer with windings made of high temperature superconductors. This transformer was taken into operation in the spring of 1997 and operated perfectly for one year. I will discuss the performance and price demands the high temperature superconductors have to fulfill to be useful in power applications and review the above mentioned transformer project and also give some insight in a running project with the goal to design, build and put in operation a 10 MVA power transformer with high temperature superconductors with low AC-losses in the windings.

  11. Recent Progress in Electrical Insulation Techniques for HTS Power Apparatus

    Science.gov (United States)

    Hayakawa, Naoki; Kojima, Hiroki; Hanai, Masahiro; Okubo, Hitoshi

    This paper describes the electrical insulation techniques at cryogenic temperatures, i.e. Cryodielectrics, for HTS power apparatus, e.g. HTS power transmission cables, transformers, fault current limiters and SMES. Breakdown and partial discharge characteristics are discussed for different electrical insulation configurations of LN2, sub-cooled LN2, solid, vacuum and their composite insulation systems. Dynamic and static insulation performances with and without taking account of quench in HTS materials are also introduced.

  12. New facility for testing LHC HTS power leads

    CERN Document Server

    Rabehl, Roger Jon; Fehér, S; Huang, Y; Orris, D; Pischalnikov, Y; Sylvester, C D; Tartaglia, M

    2005-01-01

    A new facility for testing HTS power leads at the Fermilab Magnet Test Facility has been designed and operated. The facility has successfully tested 19 pairs of HTS power leads, which are to be integrated into the Large Hadron Collider Interaction Region cryogenic feed boxes. This paper describes the design and operation of the cryogenics, process controls, data acquisition, and quench management systems. HTS power lead test results from the commissioning phase of the project are also presented.

  13. Engineering design of a high-temperature superconductor current lead

    Science.gov (United States)

    Niemann, R. C.; Cha, Y. S.; Hull, J. R.; Daugherty, M. A.; Buckles, W. E.

    As part of the US Department of Energy's Superconductivity Pilot Center Program, Argonne National Laboratory and Superconductivity, Inc., are developing high-temperature superconductor (HTS) current leads suitable for application to superconducting magnetic energy storage systems. The principal objective of the development program is to design, construct, and evaluate the performance of HTS current leads suitable for near-term applications. Supporting objectives are to (1) develop performance criteria; (2) develop a detailed design; (3) analyze performance; (4) gain manufacturing experience in the areas of materials and components procurement, fabrication and assembly, quality assurance, and cost; (5) measure performance of critical components and the overall assembly; (6) identify design uncertainties and develop a program for their study; and (7) develop application-acceptance criteria.

  14. High output power electric motors with bulk HTS elements

    Science.gov (United States)

    Kovalev, L. K.; Ilushin, K. V.; Kovalev, K. L.; Penkin, V. T.; Poltavets, V. N.; Koneev, S. M.-A.; Akimov, I. I.; Gawalek, W.; Oswald, B.; Krabbes, G.

    2003-04-01

    New types of electric machines with the rotors containing bulk HTS (YBCO and Bi-Ag) elements are presented. Different schematics of hysteresis, reluctance, “trapped field” and composed synchronous HTS machines are discussed. The two-dimensional mathematical models describing the processes in such types of HTS machines were developed on the basis of the theoretical analysis of the electrodynamic and hysteresis processes in the single-domain and polycrystal YBCO ceramic samples and plate shape Bi-Ag elements. The test results of the series of hysteresis, reluctance, “trapped field” and composed with permanent magnets HTS motors with output power rating 0.1-18 kW and current frequency 50 and 400 Hz are given. These results show that in the media of liquid nitrogen the specific output power per one weight unit of HTS motors is 4-7 times better than for conventional electric machines. Comparison of the theoretical and experimental characteristics of the developed HTS motors show that they are in good agreement. The test results for liquid nitrogen cryogenic pump system with hysteresis 500 W HTS motor are discussed. The designs and first test results of HTS motor operating in the media of liquid nitrogen with output power 100 kW and power factor more than 0.8 are given. Future development and applications of new types of HTS motors for aerospace technology, on-land industry and transport systems are discussed.

  15. Fabrication of HTS dc Bias Coil for 35 kV/90 MVA SFCL

    Institute of Scientific and Technical Information of China (English)

    Jing-Yin Zhang; Wei-Zhi Gong; Zheng-Jian Cao; Hui Hong; Bo Tian; Yang Wang; Jian-Zhong Wang; Xiao-Ye Niu; Ying Xin

    2008-01-01

    For a saturated iron core fault current limiter, superconductor is the only suitable material to make the dc bias coil, especially when the device is used in a high voltage power grid. Commonly, supercon- ducting wires are used to wind the dc bias coil. Since the performance of the wires changes greatly under magnetic fields, the calculation of the field spatial distraction is essential to the optimization of the superconducting magnet. A superconducting coil with 141000 ampere-turns magnetizing capacity made of 17600 meters of BSCCO 2223 HTS tapes was fabricated. This coil was built for a 35 kV/90 MVA saturated iron-core fault current limiter. Computer simulations on magnetic field distribution were carried out to optimize the structural design, and experiments were done to verify the performance of the coil. The configuration and the key parameters of the coil will be reported in this paper.

  16. DC current distribution mapping system of the solar panels using a HTS-SQUID gradiometer

    Science.gov (United States)

    Miyazaki, Shingo; Kasuya, Syohei; Mawardi Saari, Mohd; Sakai, Kenji; Kiwa, Toshihiko; Tsukamoto, Akira; Adachi, Seiji; Tanabe, Keiichi; Tsukada, Keiji

    2014-05-01

    Solar panels are expected to play a major role as a source of sustainable energy. In order to evaluate solar panels, non-destructive tests, such as defect inspections and response property evaluations, are necessary. We developed a DC current distribution mapping system of the solar panels using a High Critical Temperature Superconductor Superconducting Quantum Interference Device (HTS-SQUID) gradiometer with ramp edge type Josephson junctions. Two independent components of the magnetic fields perpendicular to the panel surface (∂Bz/∂x, ∂Bz/∂y) were detected. The direct current of the solar panel is visualized by calculating the composition of the two signal components, the phase angle, and mapping the DC current vector. The developed system can evaluate the uniformity of DC current distributions precisely and may be applicable for defect detection of solar panels.

  17. Status of series production and test of the HTS current leads for Wendelstein 7-X

    Energy Technology Data Exchange (ETDEWEB)

    Heller, Reinhard, E-mail: reinhard.heller@kit.edu [Karlsruhe Institute of Technology, Karlsruhe (Germany); Buscher, Klaus-Peter [Max-Planck-Institut für Plasmaphysik, Teilinstitut Greifswald, Greifswald (Germany); Drotziger, Sandra; Fietz, Walter H.; Kienzler, Andreas; Lietzow, Ralph [Karlsruhe Institute of Technology, Karlsruhe (Germany); Mönnich, Thomas [Max-Planck-Institut für Plasmaphysik, Teilinstitut Greifswald, Greifswald (Germany); Richter, Thomas [Karlsruhe Institute of Technology, Karlsruhe (Germany); Rummel, Thomas [Max-Planck-Institut für Plasmaphysik, Teilinstitut Greifswald, Greifswald (Germany); Urbach, Elisabeth [Karlsruhe Institute of Technology, Karlsruhe (Germany)

    2013-10-15

    Highlights: ► KIT is responsible for design, production and test of the HTS current leads for W7-X. In total 14 current leads with a max. current of 18.2 kA are required. ► Final acceptance test of the current leads performed at KIT using a test cryostat connected to the main vacuum vessel of the TOSKA facility. ► In general the performance of the leads is excellent and reproducible. ► Problems during series production and test related to electrical insulation, leak tightness, contact resistance between current lead and bus bar joint box. -- Abstract: The Karlsruhe Institute of Technology (KIT) is responsible for design, production and test of the High Temperature Superconductor (HTS) current leads for the stellarator Wendelstein 7-X (W7-X). In total 14 current leads with a maximum current of 18.2 kA are required. Special feature is the upside-down orientation of the current leads because of the location of the power supplies in the basement of the experimental area of W7-X. One further important requirement is the Paschen tight electrical insulation of current leads and the connection to the bus bar system. Due to some very specific manufacturing steps, budget and time restrictions, it has been mutually decided between the project partners to manufacture most of the components in house, except the HTS stacks which have been produced and delivered by industry. As the semi-finished parts were manufactured in the central workshop of KIT, the assembly of the current leads was performed in the ITEP (Institute for Technical Physics). The final acceptance test of the current leads is performed at KIT, using a dedicated test cryostat assembled beside and connected to the main vacuum vessel of the TOSKA facility. The paper describes the status of the manufacturing of the current leads. In addition attention is given to specific problems that occurred during the manufacturing and testing.

  18. A new method of reconstructing current paths in HTS tapes with defects

    Science.gov (United States)

    Podlivaev, Alexey; Rudnev, Igor

    2017-03-01

    We propose a new method for calculating current paths in high-temperature superconductive (HTS) tapes with various defects including cracks, non-superconducting inclusions, and superconducting inclusions with lower local critical current density. The calculation method is based on a model of critical state which takes into account the dependence of the critical current on the magnetic field. The method allows us to calculate the spatial distribution of currents flowing through the defective HTS tape for both currents induced by the external magnetic field and transport currents from an external source. For both cases, we performed simulations of the current distributions in these tapes with different types of defects and have shown that the combination of the action of the magnetic field and transport current leads to a more detailed identification of the boundaries and shape of the defects. The proposed method is adapted for calculating modern superconductors in real superconducting devices and may be more useful as compared to the conventional magnetometric diagnostic studies, when the tape is affected by the magnetic field only.

  19. AC loss measurements in HTS coil assemblies with hybrid coil structures

    Science.gov (United States)

    Jiang, Zhenan; Long, Nicholas J.; Staines, Mike; Badcock, Rodney A.; Bumby, Chris W.; Buckley, Robert G.; Amemiya, Naoyuki

    2016-09-01

    Both AC loss and wire cost in coil windings are critical factors for high temperature superconductor (HTS) AC machinery applications. We present AC loss measurement results in three HTS coil assemblies at 77 K and 65 K which have a hybrid coil structure comprising one central winding (CW) and two end windings (EWs) wound with ReBCO and BSCCO wires with different self-field I c values at 77 K. All AC loss results in the coil assemblies are hysteretic and the normalized AC losses in the coil assemblies at different temperatures can be scaled with the I c value of the coil assemblies. The normalised results show that AC loss in a coil assembly with BSCCO CW can be reduced by using EWs wound with high I c ReBCO wires, whilst further AC loss reduction can be achieved by replacing the BSCCO CW with ReBCO CW. The results imply that a flexible hybrid coil structure is possible which considers both AC loss and wire cost in coil assemblies.

  20. Progress of metallic superconductors in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Tachikawa, Kyoji, E-mail: tacsuper@keyaki.cc.u-tokai.ac.jp [Faculty of Engineering, Tokai University, 4-1-1, Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan)

    2013-01-15

    Highlights: ► Japanese contributions on the R and D of different metallic superconductors are summarized. ► Nb–Ti wires have been developed for MRI, accelerator, MAGLEV train and other applications. ► Multifilamentary Nb{sub 3}Sn wires with excellent performance have been developed for high-field use. ► Long-length Nb{sub 3}Al wires with promising strain tolerance have been fabricated by a new process. -- Abstract: This article overviews the development of metallic superconductors in Japan covering different kinds of alloys and intermetallic compounds. Metallic superconductors have opened many new application areas in science and technology. Japan has been one of the leading countries in the world, both in the research and development and in large-scale manufacturing of metallic superconductors.

  1. High-temperature superconductors

    CERN Document Server

    Saxena, Ajay Kumar

    2010-01-01

    The present book aims at describing the phenomenon of superconductivity and high-temperature superconductors discovered by Bednorz and Muller in 1986. The book covers the superconductivity phenomenon, structure of high-Tc superconductors, critical currents, synthesis routes for high Tc materials, superconductivity in cuprates, the proximity effect and SQUIDs, theories of superconductivity and applications of superconductors.

  2. The application of high temperature superconductors to space electrical power distribution components

    Science.gov (United States)

    Aron, Paul R.; Myers, Ira T.

    1988-01-01

    Some important space based electrical power distribution systems and components are examined to determine what might be achieved with the introduction of high temperature superconductors (HTS). Components that are compared in a before-and-after fashion include transformers, transmission lines, and capacitors. It is concluded that HTS has its greatest effect on the weight associated with transmission lines, where the weight penalty could be reduced by as much as 130 kg/kW/km of cable. Transformers, because 28 percent of their mass is in the conductor, are reduced in weight by the same factor. Capacitors are helped the least with only negligible savings possible. Finally, because HTS can relax the requirement to use alternating current in order to reduce conductor mass, it will be possible to generate significant savings by eliminating most transformers and capacitors.

  3. Commercialization of Medium Voltage HTS Triax TM Cable Systems

    Energy Technology Data Exchange (ETDEWEB)

    Knoll, David

    2012-12-31

    The original project scope that was established in 2007 aimed to install a 1,700 meter (1.1 mile) medium voltage HTS Triax{TM} cable system into the utility grid in New Orleans, LA. In 2010, however, the utility partner withdrew from the project, so the 1,700 meter cable installation was cancelled and the scope of work was reduced. The work then concentrated on the specific barriers to commercialization of HTS cable technology. The modified scope included long-length HTS cable design and testing, high voltage factory test development, optimized cooling system development, and HTS cable life-cycle analysis. In 2012, Southwire again analyzed the market for HTS cables and deemed the near term market acceptance to be low. The scope of work was further reduced to the completion of tasks already started and to testing of the existing HTS cable system in Columbus, OH. The work completed under the project included: • Long-length cable modeling and analysis • HTS wire evaluation and testing • Cable testing for AC losses • Optimized cooling system design • Life cycle testing of the HTS cable in Columbus, OH • Project management. The 200 meter long HTS Triax{TM} cable in Columbus, OH was incorporated into the project under the initial scope changes as a test bed for life cycle testing as well as the site for an optimized HTS cable cooling system. The Columbus cable utilizes the HTS TriaxTM design, so it provided an economical tool for these of the project tasks.

  4. Amplitude and frequency dependence of hysteresis loss in a magnet-superconductor levitation system

    Science.gov (United States)

    Yang, Z. J.; Hull, J. R.; Mulcahy, T. M.; Rossing, T. D.

    1995-08-01

    Using an electromagnetically controlled mechanical pendulum, we measured the energy loss for different amplitudes in a magnetic levitation system that contained high temperature superconductors (HTSs). Two procedures were followed to measure losses at 77 K for frequencies of 93.8 mHz to 80 Hz. In the first procedure, the distance between the permanent magnet and the HTS levitator was the same as that during (field) cooling. In the second procedure, the magnet was lowered (after cooling) closer to the HTS levitator before the measurements were performed. The experimental data show that these two procedures give essentially the same results at the same distance despite different cooling (and magnetization) histories for melt-textured YBaCuO levitators, and the frequency-independent energy loss is a power-law function of amplitude. We attribute the energy loss to magnetic hysteresis in the superconductor.

  5. Improvement of persistent magnetic field trapping in bulk Y-Ba-Cu-O superconductors

    Science.gov (United States)

    Chen, In-Gann; Weinstein, Roy

    1993-01-01

    For type-II superconductors, magnetic field can be trapped due to persistent internal supercurrent. Quasi-persistent magnetic fields near 2 T at 60 K (and 1.4 T at 77 K) have been measured in minimagnets made of proton-irradiated melt-textured Y-Ba-Cu-O (MT-Y123) samples. Using the trapping effect, high-field permanent magnets with dipole, quadrupole, or more complicated configurations can be made of existing MT-Y123 material, thus bypassing the need for high-temperature superconductor (HTS) wires. A phenomenological current model has been developed to account for the trapped field intensity and profile in HTS samples. This model is also a guide to select directions of materials development to further improve field trapping properties. General properties such as magnetic field intensities, spatial distributions, stabilities, and temperature dependence of trapped field are discussed.

  6. Anisotropy Effect on Levitation Performance of Bulk High-Tc Superconductors Above a Permanent Magnet Guideway

    Science.gov (United States)

    Zheng, Jun; Liao, Xinglin; Jing, Hailian; Lin, Qunxu; Ma, Guangtong; Yen, Fei; Wang, Suyu; Wang, Jiasu

    The anisotropy properties of bulk high-temperature superconductors (HTSCs) are taken into consideration for the application of high-temperature superconducting (HTS) Maglev systems, which are especially based on the different flux-trapping capabilities as well as critical current density, Jc, values between the growth section boundary (GSB) and the growth sections (GS) in bulk superconductors. By adjusting the angle between the GSB of bulk HTSCs and the strongest magnetic field position of a permanent magnet guideway (PMG), the levitation force and its relaxation processes are compared at different field-cooling conditions. Experimental results show that the levitation capability and the suppression of levitation force decay can be enhanced by optimizing the GS/GSB alignment of every bulk HTSC above the PMG. Meanwhile, our conclusions may provide references to other HTS maglev systems with small levitation gaps, i.e., superconducting magnetic bearings.

  7. Thermal analysis for the HTS stator consisting of HTS armature windings and an iron core for a 2.5 kW HTS generator

    Science.gov (United States)

    Song, P.; Qu, T.-M.; Lai, L.-F.; Wu, M.-S.; Yu, X.-Y.; Han, Z.

    2016-05-01

    Most present demonstrations of high-temperature superconducting (HTS) synchronous motors/generators are partially superconducting, only installing HTS coils on the rotor as excitation windings. The possible applicability of HTS armature windings is an interesting research topic because these windings can certainly increase the power density attributed to a potentially high armature loading capacity. In this study, we analysed the thermal behaviours of a developed 2.5 kW-300 rpm synchronous generator prototype that consists of an HTS stator with Bi-2223-Ag armature windings on an iron core and a permanent magnet (PM) rotor. The entire HTS stator, including the iron core, is cooled with liquid nitrogen through conduction cooling. The rated frequency is set at 10 Hz to reduce AC loss. The properties of the HTS windings and the iron core are characterized, and the temperatures in the HTS stator under different operation conditions are measured. The estimated iron loss is 11.5 W under operation in 10 Hz at liquid nitrogen temperature. Conduction cooling through the silicon iron core is sufficient to cool the iron core and to compensate for the temperature increment caused by iron loss. The stable running capacity is limited to 1.6 kW when the armature current is 12.6 A (effective values) due to the increasing temperature in the slots as a result of the AC loss in the HTS coils. The thermal contact between the HTS coils and the cooling media should be improved in the future to take away the heat generated by AC loss.

  8. Influence of superconductor film composition on adhesion strength of coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Kesgin, Ibrahim; Khatri, Narayan; Liu, Yuhao; Delgado, Louis; Galstyan, Eduard; Selvamanickam, Venkat

    2015-11-20

    The effect of high temperature superconductor (HTS) film composition on the adhesion strength of rare- earth barium copper oxide coated conductors (CCs) has been studied. It has been found that the mechanical integrity of the superconductor layer is very susceptible to the defects especially those along the ab plane, probably due to the weak interfaces between the defects and the matrix. Gd and Y in the standard composition were substituted with Sm and the number of in-plane defects was drastically reduced. Consequently, a four-fold increase in adhesion or peeling strength in Sm-based CCs was achieved compared to the standard GdYBCO samples.

  9. Fracture analysis of a transversely isotropic high temperature superconductor strip based on real fundamental solutions

    Science.gov (United States)

    Gao, Zhiwen; Zhou, Youhe

    2015-04-01

    Real fundamental solution for fracture problem of transversely isotropic high temperature superconductor (HTS) strip is obtained. The superconductor E-J constitutive law is characterized by the Bean model where the critical current density is independent of the flux density. Fracture analysis is performed by the methods of singular integral equations which are solved numerically by Gauss-Lobatto-Chybeshev (GSL) collocation method. To guarantee a satisfactory accuracy, the convergence behavior of the kernel function is investigated. Numerical results of fracture parameters are obtained and the effects of the geometric characteristics, applied magnetic field and critical current density on the stress intensity factors (SIF) are discussed.

  10. Superconductor stripes move on

    Energy Technology Data Exchange (ETDEWEB)

    Tranquada, J. [Physics Department, Brookhaven National Laboratory, Upton, NY (United States)

    1999-11-01

    Differences in fundamental assumptions are behind much of the controversy among theorists over the cause of high-temperature superconductivity the absence of resistance to electrical current at temperatures as high as 130 K in layered copper-oxide compounds. One common assumption is that the charge carriers are distributed uniformly throughout the all-important CuO{sub 2} layers. However, there is growing experimental evidence that this is not the case and that 'stripes' of charge form in these puzzling materials. Now a significant step forward in the struggle to understand the behaviour of charge carriers in high-temperature superconductors has been made at the Oak Ridge National Laboratory in the US. (UK)

  11. Low Friction Cryostat for HTS Power Cable of Dutch Project

    NARCIS (Netherlands)

    Chevtchenko, O.; Zuijderduin, R.; Smit, J.; Willen, D.; Lentge, H.; Thidemann, C.; Traeholt, C.

    2012-01-01

    Particulars of 6 km long HTS AC power cable for Amsterdam project are: a cable has to fit in an annulus of 160 mm, with only two cooling stations at the cable ends [1]. Application of existing solutions for HTS cables would result in excessively high coolant pressure drop in the cable, possibly affe

  12. Development of HTS power cable using YBCO coated conductor

    Science.gov (United States)

    Mukoyama, Shinichi; Yagi, Masashi; Hirano, Hironobu; Yamada, Yutaka; Izumi, Teruo; Shiohara, Yuh

    2006-10-01

    Reductions of AC losses and of cost of HTS power cables are important to put it into practical power networks. Since an YBCO-coated-conductor (YBCO tape) has higher Jc and better magnetic property than a Bi2223-Ag-sheathed-tape, an AC power cable using YBCO tapes will obtain higher performance than XLPE-cables and HTS cables using BSCCO tapes in future. Especially, an YBCO HTS cable will be expected to become a higher economical cable than a Bi cable because an YBCO tape reduced its AC losses and its wire cost. We have started developing HTS power cables using YBCO tapes. Mechanical properties, superconducting properties and other electro magnetic properties of YBCO tapes have been measured to estimate the applicability to the HTS cable. Moreover, we have developed some technologies to bring out latent potentials of YBCO tapes.

  13. Permanent magnet with MgB2 bulk superconductor

    Science.gov (United States)

    Yamamoto, Akiyasu; Ishihara, Atsushi; Tomita, Masaru; Kishio, Kohji

    2014-07-01

    Superconductors with persistent zero-resistance currents serve as permanent magnets for high-field applications requiring a strong and stable magnetic field, such as magnetic resonance imaging. The recent global helium shortage has quickened research into high-temperature superconductors (HTSs)—materials that can be used without conventional liquid-helium cooling to 4.2 K. Herein, we demonstrate that 40-K-class metallic HTS magnesium diboride (MgB2) makes an excellent permanent bulk magnet, maintaining 3 T at 20 K for 1 week with an extremely high stability (cryocoolers, making MgB2 bulks promising for the next generation of Tesla-class permanent-magnet applications.

  14. Superconductor Requirements and Characterization for High Field Accelerator Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Barzi, E.; Zlobin, A. V.

    2015-05-01

    The 2014 Particle Physics Project Prioritization Panel (P5) strategic plan for U.S. High Energy Physics (HEP) endorses a continued world leadership role in superconducting magnet technology for future Energy Frontier Programs. This includes 10 to 15 T Nb3Sn accelerator magnets for LHC upgrades and a future 100 TeV scale pp collider, and as ultimate goal that of developing magnet technologies above 20 T based on both High Temperature Superconductors (HTS) and Low Temperature Superconductors (LTS) for accelerator magnets. To achieve these objectives, a sound conductor development and characterization program is needed and is herein described. This program is intended to be conducted in close collaboration with U.S. and International labs, Universities and Industry.

  15. Design of High Field Solenoids made of High Temperature Superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Bartalesi, Antonio; /Pisa U.

    2010-12-01

    This thesis starts from the analytical mechanical analysis of a superconducting solenoid, loaded by self generated Lorentz forces. Also, a finite element model is proposed and verified with the analytical results. To study the anisotropic behavior of a coil made by layers of superconductor and insulation, a finite element meso-mechanic model is proposed and designed. The resulting material properties are then used in the main solenoid analysis. In parallel, design work is performed as well: an existing Insert Test Facility (ITF) is adapted and structurally verified to support a coil made of YBa{sub 2}Cu{sub 3}O{sub 7}, a High Temperature Superconductor (HTS). Finally, a technological winding process was proposed and the required tooling is designed.

  16. Influence of the lateral movement on the levitation and guidance force in the high-temperature superconductor maglev system

    Science.gov (United States)

    Song, Honghai; de Haas, Oliver; Beyer, Christoph; Krabbes, Gernot; Verges, Peter; Schultz, Ludwig

    2005-05-01

    After the levitation force relaxation was studied for different field-cooling height and working-levitation height, the high-temperature superconductor (HTS) bulk was horizontally moved in the lateral direction above the permanent magnet guideway. Both levitation and guidance force were collected by the measurement system at the same time. It was found that the decay of levitation force is dependent on both the maximum lateral displacement and the movement cycle times, while the guidance force hysteresis curve does not change after the first cycle. This work provided scientific analysis for the HTS maglev system design.

  17. Experimental and theoretical investigations on the singularity of the intensity factor of the current in high temperature superconductors

    Science.gov (United States)

    Zhang, Xingyi; Huang, Yi; Zhou, Jun; Zhou, Youhe

    2013-08-01

    This paper presents experimental and analytical investigations into the distribution of current around a through-edge crack located in an infinitely long cylindrical high temperature superconductor (HTS) on the basis of the Bean model. Current distributions around the crack in the HTS without deformation are obtained by a simple conformal mapping. It is shown that the current is singular at the tip of the crack. An intensity factor of the current is introduced to characterize the singularity, the order of which is equal to -1. Additionally, an experimental verification according to the trapped field distributions around the crack is carried out, and the experimental results show little difference with the theoretical analysis.

  18. Practical superconductor development for electrical power applications

    Energy Technology Data Exchange (ETDEWEB)

    Goretta, K.C. (comp.)

    1992-10-01

    Development of useful high-critical-temperature (high-[Tc]) superconductors requires synthesis of superconducting compounds; fabrication of wires, tapes, and films from these compounds; production of composite structures that incorporate stabilizers or insulators; and design and testing of efficient components. This report describes the technical progress of research and development efforts aimed at producing superconducting components that are based on the Y-Ba-Cu, Bi-Sr-Ca-Cu, Bi-Pb-Sr-Ca-Cu, and (TI,Pb)-(Ba,Sr)-Ca-Cu oxide systems. Topics discussed are synthesis and heat treatment of high-[Tc] superconductors, formation of monolithic and composite wires and tapes, superconductor/metal connectors, characterization of structures and superconducting and mechanical properties, fabrication and properties of thin films, and development of prototype components. Collaborations with industry and academia are documented.

  19. Trapped field measurements of Gd-Ba-Cu-O bulk superconductor in controlled pulse field magnetizing

    Energy Technology Data Exchange (ETDEWEB)

    Ida, T [Department of Electronic Control Engineering, Hiroshima National College of Maritime Technology, 4272-1, Higashino, Ohsakikamijima-cho, Toyota-gun, Hiroshima 725-0231 (Japan); Kimura, Y; Sano, T; Yamaguchi, K; Izumi, M [Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology, 2-1-6, Etchu-jima, Koto-ku, Tokyo 135-8533 (Japan); Miki, M [Kitano Seiki Co. Ltd., 7-13-7, Chuo, Ohta-ku, Tokyo 143-0024 (Japan)], E-mail: ida@hiroshima-cmt.ac.jp

    2008-02-01

    For large-scale electric power application of the melt-processed high temperature superconductor (HTS) bulks, especially at rotating machine, development of trapping much higher magnetic fields by using pulsed magnetization technique is essential. It is difficult to use static field cooling (FCM) technique that is most effective magnetizing method for the general industrial HTS applications, because the FCM requires large-scale superconducting magnets. Because the rise in temperature due to the magnetic flux motion decreases the pinning force, we controlled the magnetic flux penetrating to the bulk for the effective magnetization. A couple of vortex-type copper coils applied a magnetic field to a Gd-Ba-Cu-O bulk, which dimension was 45mm in diameter and 19 mm in thickness. HTS bulk was magnetized by the controlled pulse field without passive LCR pulse. We controlled waveform by using the discharge current that IGBT chopper in pulse magnetizer intermitted. We applied the pulse magnetic field with the various risetime to the HTS bulk in liquid nitrogen. The various conditions of the controlled waveform pulse to trap well-dressed profile magnetized the Gd-Ba-Cu-O bulk, strongly at 77K. In the present study, we show several properties which was measured in the PFM of the HTS bulk.

  20. Synthesis and Characterization of Hollow Titanium Silicalite Zeolite(HTS)

    Institute of Scientific and Technical Information of China (English)

    Lin Min; Zhu Bin; Shu Xingtian; Wang Xieqing

    2008-01-01

    29Si-NMR and 1H-NMR were used to follow up the basic hydrolysis of tetraethyl orthosilicate (TOES) and the results showed that species of monomer, dimer, trimer, cyclic and polymer silicates were formed. The monomer and dimer were favorable for the high activity of zeolite. XRD, 13C CP/MAS and 29Si NMR were used to trace the crystallization process of hollow titanium silicalite zeolites (HTS). The results showed that the induction period of HTS was 80 min, and subsequently it took next 10 min to form HTS and the remaining time of the crystallization period might function for cleaning up the pores and/or washing off the impurities from the HTS zeolite. The catalytic oxidation performance of HTS zeolite is different from that of the acid activity of zeolite in which the conventional definition of crystallinity does not reflect the catalytic oxidation activity proportionally. The synthesized HTS samples were character-ized by XRD, FT-IR, UV-Vis and Raman spectra. It was confirmed that Ti was incorporated into the zeolite framework. The synthesized HTS samples revealed good repeatability and high activity for oxidation of phenol into diphenol.

  1. Modeling and simulation of HTS cables for scattering parameter analysis

    Science.gov (United States)

    Bang, Su Sik; Lee, Geon Seok; Kwon, Gu-Young; Lee, Yeong Ho; Chang, Seung Jin; Lee, Chun-Kwon; Sohn, Songho; Park, Kijun; Shin, Yong-June

    2016-11-01

    Most of modeling and simulation of high temperature superconducting (HTS) cables are inadequate for high frequency analysis since focus of the simulation's frequency is fundamental frequency of the power grid, which does not reflect transient characteristic. However, high frequency analysis is essential process to research the HTS cables transient for protection and diagnosis of the HTS cables. Thus, this paper proposes a new approach for modeling and simulation of HTS cables to derive the scattering parameter (S-parameter), an effective high frequency analysis, for transient wave propagation characteristics in high frequency range. The parameters sweeping method is used to validate the simulation results to the measured data given by a network analyzer (NA). This paper also presents the effects of the cable-to-NA connector in order to minimize the error between the simulated and the measured data under ambient and superconductive conditions. Based on the proposed modeling and simulation technique, S-parameters of long-distance HTS cables can be accurately derived in wide range of frequency. The results of proposed modeling and simulation can yield the characteristics of the HTS cables and will contribute to analyze the HTS cables.

  2. Discovery of benzofuran propanoic acid GPR120 agonists: From uHTS hit to mechanism-based pharmacodynamic effects.

    Science.gov (United States)

    Lombardo, Matthew; Bender, Kate; London, Clare; Kirkland, Melissa; Mane, Joel; Pachanski, Michele; Geissler, Wayne; Cummings, John; Habulihaz, Bahanu; Akiyama, Taro E; Di Salvo, Jerry; Madeira, Maria; Pols, Joanna; Powles, Mary Ann; Finley, Michael F; Johnson, Eric; Roussel, Thomas; Uebele, Victor N; Crespo, Alejandro; Leung, Dennis; Alleyne, Candice; Trusca, Dorina; Lei, Ying; Howard, Andrew D; Ujjainwalla, Feroze; Tata, James R; Sinz, Christopher J

    2016-12-01

    The transformation of an aryloxybutanoic acid ultra high-throughput screening (uHTS) hit into a potent and selective series of G-protein coupled receptor 120 (GPR120) agonists is reported. uHTS hit 1 demonstrated an excellent rodent pharmacokinetic profile and selectivity over the related fatty acid receptor GPR40, but only modest GPR120 potency. Optimization of the "left-hand" aryl group led to compound 6, which demonstrated a GPR120 mechanism-based pharmacodynamic effect in a mouse oral glucose tolerance test (oGTT). Further optimization gave rise to the benzofuran propanoic acid series (exemplified by compound 37), which demonstrated acute mechanism-based pharmacodynamic effects. The combination of in vivo efficacy and attractive rodent pharmacodynamic profiles suggests compounds generated from this series may afford attractive candidates for the treatment of Type 2 diabetes.

  3. Fine uniform filament superconductors

    Science.gov (United States)

    Riley, Jr., Gilbert N.; Li, Qi; Roberts, Peter R.; Antaya, Peter D.; Seuntjens, Jeffrey M.; Hancock, Steven; DeMoranville, Kenneth L.; Christopherson, Craig J.; Garrant, Jennifer H.; Craven, Christopher A.

    2002-01-01

    A multifilamentary superconductor composite having a high fill factor is formed from a plurality of stacked monofilament precursor elements, each of which includes a low density superconductor precursor monofilament. The precursor elements all have substantially the same dimensions and characteristics, and are stacked in a rectilinear configuration and consolidated to provide a multifilamentary precursor composite. The composite is thereafter thermomechanically processed to provide a superconductor composite in which each monofilament is less than about 50 microns thick.

  4. The normal state of high temperature oxide superconductor

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Looking back on the experiments about the normal state of thehigh temperature superconductor (HTS), the authors point out nine important experimental results. On the basis of these results, the authors have argued that the two-dimension, two-subsystem Hamiltonian is the appropriate starting point for describing the normal state of HTS. By this Hamiltonian, using the decoupling approximation of Green's function method by Kaga through numerical calculations, the authors have obtained the temperature dependent pseudogap in the density of states (DOS), which is consistent qualitatively with the experimental results by angle-resolved photoemission spectroscopy (ARPES). Theoretically, this Hamiltonian has the superconducting order parameter of d+s symmetry with d-wave as the main component, which is consistent with experiments. Further, the quantum electronic liquid in HTS is a near Fermi liquid in which there is coexistence of the delocalized states and nearly localized states, and there is finite probability for the nearly localized carriers to form the nearly localized carrier pairs at any finite temperature.

  5. Superconductor rotor cooling system

    Science.gov (United States)

    Gamble, Bruce B.; Sidi-Yekhlef, Ahmed; Schwall, Robert E.; Driscoll, David I.; Shoykhet, Boris A.

    2002-01-01

    A system for cooling a superconductor device includes a cryocooler located in a stationary reference frame and a closed circulation system external to the cryocooler. The closed circulation system interfaces the stationary reference frame with a rotating reference frame in which the superconductor device is located. A method of cooling a superconductor device includes locating a cryocooler in a stationary reference frame, and transferring heat from a superconductor device located in a rotating reference frame to the cryocooler through a closed circulation system external to the cryocooler. The closed circulation system interfaces the stationary reference frame with the rotating reference frame.

  6. Photothermal measurements of superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kino, G.S.; Studenmund, W.R.; Fishman, I.M. [Stanford Univ., Stanford, CA (United States)

    1996-12-31

    A photothermal technique has been used to measure diffusion and critical temperature in high temperature superconductors. The technique is particularly suitable for determining material quality and inhomogeneity.

  7. Low Friction Cryostat for HTS Power Cable of Dutch Project

    DEFF Research Database (Denmark)

    Chevtchenko, Oleg; Zuijderduin, Roy; Smit, Johan;

    2012-01-01

    Particulars of 6km long HTS AC power cable for Amsterdam project are: a cable has to fit in an annulus of 160mm, with only two cooling stations at the cable ends [1]. Application of existing solutions for HTS cables would result in excessively high coolant pressure drop in the cable, possibly...... affecting public acceptance of the project. In order to solve this problem, a model cryostat was developed consisting of alternating rigid and flexible sections and hydraulic tests were conducted using sub-cooled liquid nitrogen. In the 47 m-long cryostat, containing a full-size HTS cable model, measured....... A flexible dummy HTS cable was inserted into this cryostat and sub-cooled liquid nitrogen was circulated in the annulus between the dummy cable surface and the inner cryostat surface. In the paper details are presented of the cryostat, of the measurement setup, of the experiment and of the results....

  8. Critical current measurement for design of HTS DC power cables

    Science.gov (United States)

    Watanabe, Hirofumi

    2017-02-01

    Critical currents of HTS DC power cables were calculated. In the calculation a relationship between critical current density and magnetic flux density proposed by Gömöry et al. [1] was used and the parameters used in the relationship were obtained by the critical current measurements with respect to the external magnetic field for a sample of the HTS tape. Numerical models of cables were composed and their critical currents were calculated, which showed the strong dependence on the arrangement of the HTS tapes in the cable. Critical current measurements of model cables assembled based on the calculations showed that the measured critical currents also depended on the arrangement of the HTS tapes strongly. The calculated results were compared with the experimental results, which showed that the experimental results agreed well with the calculated results.

  9. Evaluation of micro-parallel liquid chromatography as a method for HTS-coupled actives verification.

    Science.gov (United States)

    Simeonov, Anton; Yasgar, Adam; Klumpp, Carleen; Zheng, Wei; Shafqat, Naeem; Oppermann, Udo; Austin, Christopher P; Inglese, James

    2007-12-01

    The identification of biologically active compounds from high-throughput screening (HTS) can involve considerable postscreening analysis to verify the nature of the sample activity. In this study we evaluated the performance of micro-parallel liquid chromatography (microPLC) as a separation-based enzyme assay platform for follow-up of compound activities found in quantitative HTS of two different targets, a hydrolase and an oxidoreductase. In an effort to couple secondary analysis to primary screening we explored the application of microPLC immediately after a primary screen. In microPLC, up to 24 samples can be loaded and analyzed simultaneously via high-performance liquid chromatography within a specially designed cartridge. In a proof-of-concept experiment for screen-coupled actives verification, we identified, selected, and consolidated the contents of "active" wells from a 1,536-well format HTS experiment into a 384-well plate and subsequently analyzed these samples by a 24-channel microPLC system. The method utilized 0.6% of the original 6-microl 1,536-well assay for the analysis. The analysis revealed several non-biological-based "positive" samples. The main examples included "false" enzyme activators resulting from an increase in well fluorescence due to fluorescent compound or impurity. The microPLC analysis also provided a verification of the activity of two activators of glucocerebrosidase. We discuss the benefits of microPLC and its limitations from the standpoint of ease of use and integration into a seamless postscreen workflow.

  10. Magneto-optical studies of magnetization processes in high-Tc superconductors structure.

    Energy Technology Data Exchange (ETDEWEB)

    Vlasko-Vlasox, V. K.

    1998-12-02

    Magneto-optical imaging is a powerful tool for nondestructive quality control and scientific research through visualization of magnetic fields around any magnetic flux or current carrying sample. It allows real time observations of domain structures and their transformations in magnetics, static and dynamic field patterns due to inhomogeneous currents in electric circuits and superconductors, and reveals distortions of the fields due to defects. In addition to qualitative pictures showing different details in the intensities of the magneto-optical images, one can obtain quantitative maps of field distributions and retrieve values of the underlying currents or magnetization variations. In this review we discuss the advantages of magneto-optics for studies of superconductors, show its place among other techniques, and report recent results in magneto-optical investigations of high temperature superconductors (HTS).

  11. Current distribution among layers of single phase HTS cable conductor

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Y.B., E-mail: yeaber@ncepu.edu.cn [Key Laboratory of HV and EMC Beijing, State Key Laboratory for Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, No. 2 Beinong Road, Changping District, Beijing 102206 (China); Wang, Y.S., E-mail: yswang@ncepu.edu.cn [Key Laboratory of HV and EMC Beijing, State Key Laboratory for Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, No. 2 Beinong Road, Changping District, Beijing 102206 (China); Pi, W., E-mail: ppiiwei@ncepu.edu.cn [Key Laboratory of HV and EMC Beijing, State Key Laboratory for Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, No. 2 Beinong Road, Changping District, Beijing 102206 (China); Ju, P., E-mail: jupeng-cool@153.com [Key Laboratory of HV and EMC Beijing, State Key Laboratory for Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, No. 2 Beinong Road, Changping District, Beijing 102206 (China); Wang, Y.S., E-mail: wangyixuan@epri.sgcc.com.cn [Power System Department, China Electric Power Research Institute, No. 15 Qinghexiaoying East Road, Haidian District, Beijing 100198 (China)

    2014-12-15

    Highlights: • A 1.5 m long HTS model cable with 4 layers designed by the uniform current principle has been built. • It is testified that the current distribution is influenced by the proximity effect. • The magnetic flux density and current density have been analyzed. • AC losses of tested current are larger than those of uniform current. - Abstract: High temperature superconducting (HTS) power cable shows high application prospect in modern power transmission, as it is superior over conventional transmission lines in high engineering current density and environmental friendliness. Its configuration is generally composed of several HTS layers designed with the principle of uniform current distribution, but there are few experimental results to verify the distribution. In this paper, a HTS cable model was designed based on the principle of uniform current, and the current distributions among layers in an HTS cable model were measured by Rogowski coils. The results provide an important basis for design of multi-layer HTS cable.

  12. The Astro-H high temperature superconductor lead assemblies

    Science.gov (United States)

    Canavan, E. R.; James, B. L.; Hait, T. P.; Oliver, A.; Sullivan, D. F.

    2014-11-01

    The Soft X-ray Spectrometer (SXS) instrument, one of several instruments on JAXA's Astro-H mission, will observe diffuse X-ray sources with unparalleled spectral resolution using a microcalorimeter array operating at 50 mK. The array is cooled with a multi-stage Adiabatic Demagnetization Refrigerator mounted on a 40 l helium tank. The tank is at the center of a typical 'shell in shell' cryostat, with the innermost shield cooled by a JT cryocooler, and successive outer shields cooled by stirling-cycle cryocoolers. To achieve a multi-year liquid helium lifetime and to avoid exceeding the limited capacity of the JT cooler, very strict requirements are placed on every source of heat leak into these surfaces from the higher temperature shields. However, each ADR stage draws a maximum of 2 A, and the Wiedemann-Franz Law precludes even an optimized set of normal-metal leads capable of such high current from achieving the required low thermal conductance. Instead, a set of lead assemblies have been developed based on narrow high temperature superconductor (HTS) tapes derived from commercially available coated conductors. Although the HTS tapes are flexible and have high tensile strength, they are extremely sensitive to damage through a number of mechanisms. A robust set of assemblies have been developed that provide mechanical support to the tapes, provide appropriate interfaces at either end, and yet still meet the challenging thermal requirements. An Engineering Model (EM) set of HTS lead assemblies have survived environmental testing, both as individual units and as part of the EM cryostat, and have performed without problem in recent operation of the EM instrument. The Flight Model (FM) HTS lead assemblies are currently nearing completion.

  13. Rethinking molecular similarity: comparing compounds on the basis of biological activity.

    Science.gov (United States)

    Petrone, Paula M; Simms, Benjamin; Nigsch, Florian; Lounkine, Eugen; Kutchukian, Peter; Cornett, Allen; Deng, Zhan; Davies, John W; Jenkins, Jeremy L; Glick, Meir

    2012-08-17

    Since the advent of high-throughput screening (HTS), there has been an urgent need for methods that facilitate the interrogation of large-scale chemical biology data to build a mode of action (MoA) hypothesis. This can be done either prior to the HTS by subset design of compounds with known MoA or post HTS by data annotation and mining. To enable this process, we developed a tool that compares compounds solely on the basis of their bioactivity: the chemical biological descriptor "high-throughput screening fingerprint" (HTS-FP). In the current embodiment, data are aggregated from 195 biochemical and cell-based assays developed at Novartis and can be used to identify bioactivity relationships among the in-house collection comprising ~1.5 million compounds. We demonstrate the value of the HTS-FP for virtual screening and in particular scaffold hopping. HTS-FP outperforms state of the art methods in several aspects, retrieving bioactive compounds with remarkable chemical dissimilarity to a probe structure. We also apply HTS-FP for the design of screening subsets in HTS. Using retrospective data, we show that a biodiverse selection of plates performs significantly better than a chemically diverse selection of plates, both in terms of number of hits and diversity of chemotypes retrieved. This is also true in the case of hit expansion predictions using HTS-FP similarity. Sets of compounds clustered with HTS-FP are biologically meaningful, in the sense that these clusters enrich for genes and gene ontology (GO) terms, showing that compounds that are bioactively similar also tend to target proteins that operate together in the cell. HTS-FP are valuable not only because of their predictive power but mainly because they relate compounds solely on the basis of bioactivity, harnessing the accumulated knowledge of a high-throughput screening facility toward the understanding of how compounds interact with the proteome.

  14. Fabrication of high temperature superconductors

    Science.gov (United States)

    Balachandran, Uthamalingam; Dorris, Stephen E.; Ma, Beihai; Li, Meiya

    2003-06-17

    A method of forming a biaxially aligned superconductor on a non-biaxially aligned substrate substantially chemically inert to the biaxially aligned superconductor comprising is disclosed. A non-biaxially aligned substrate chemically inert to the superconductor is provided and a biaxially aligned superconductor material is deposited directly on the non-biaxially aligned substrate. A method forming a plume of superconductor material and contacting the plume and the non-biaxially aligned substrate at an angle greater than 0.degree. and less than 90.degree. to deposit a biaxially aligned superconductor on the non-biaxially aligned substrate is also disclosed. Various superconductors and substrates are illustrated.

  15. Present status and future trends of R and D for HTS rotational machines in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Tsukamoto, Osami, E-mail: osami-t@ynu.ac.jp

    2014-09-15

    Highlights: • R and D statuses of various HTS rotating machines developed in Japan are overviewed. • Design studies of various types of HTS wind power generators conducted in Japan are assessed. • Based on the present R and D statuses, future technical trends of HTS machines are discussed. • Introduction of iron cores into HTS windings drastically reduces amount of HTS wires and cost of HTS machines. - Abstract: Various HTS rotating machines, from multiple MW class to several 10 kW class, are being developed in Japan. R and D statuses of those machines are reviewed. Design studies of various types of HTS wind power generators are also conducted in Japan and their merits and demerits are discussed. Based on the present R and D statuses, future technical trends of HTS machines are discussed.

  16. Iron-based superconductors: A new family to find the origin of high Tc superconductivity

    Institute of Scientific and Technical Information of China (English)

    Dao-xin Yao

    2011-01-01

    Since the discovery of iron-based superconductors in 2008 [1],a new tide of study on high Tc superconductors spreads worldwide quickly.After a few years' intensive study,many new compounds of iron-based superconductors have been found and their properties have been disclosed.The great achievement is attributed to the modern experimental techniques,fast developing numerical methods and improved theories during the study of cuprate superconductors or more generally strongly correlated electron systems.For instance,the Fermi surface,band structure and superconducting gap for a new compound could be measured quickly by modern ARPES technique [2].

  17. Large-scale HTS bulks for magnetic application

    Energy Technology Data Exchange (ETDEWEB)

    Werfel, Frank N., E-mail: werfel@t-online.de [Adelwitz Technologiezentrum GmbH (ATZ), Rittergut Adelwitz 16, 04886 Arzberg-Adelwitz (Germany); Floegel-Delor, Uta; Riedel, Thomas; Goebel, Bernd; Rothfeld, Rolf; Schirrmeister, Peter; Wippich, Dieter [Adelwitz Technologiezentrum GmbH (ATZ), Rittergut Adelwitz 16, 04886 Arzberg-Adelwitz (Germany)

    2013-01-15

    Highlights: ► ATZ Company has constructed about 130 HTS magnet systems. ► Multi-seeded YBCO bulks joint the way for large-scale application. ► Levitation platforms demonstrate “superconductivity” to a great public audience (100 years anniversary). ► HTS magnetic bearings show forces up to 1 t. ► Modular HTS maglev vacuum cryostats are tested for train demonstrators in Brazil, China and Germany. -- Abstract: ATZ Company has constructed about 130 HTS magnet systems using high-Tc bulk magnets. A key feature in scaling-up is the fabrication of YBCO melts textured multi-seeded large bulks with three to eight seeds. Except of levitation, magnetization, trapped field and hysteresis, we review system engineering parameters of HTS magnetic linear and rotational bearings like compactness, cryogenics, power density, efficiency and robust construction. We examine mobile compact YBCO bulk magnet platforms cooled with LN{sub 2} and Stirling cryo-cooler for demonstrator use. Compact cryostats for Maglev train operation contain 24 pieces of 3-seed bulks and can levitate 2500–3000 N at 10 mm above a permanent magnet (PM) track. The effective magnetic distance of the thermally insulated bulks is 2 mm only; the stored 2.5 l LN{sub 2} allows more than 24 h operation without refilling. 34 HTS Maglev vacuum cryostats are manufactured tested and operate in Germany, China and Brazil. The magnetic levitation load to weight ratio is more than 15, and by group assembling the HTS cryostats under vehicles up to 5 t total loads levitated above a magnetic track is achieved.

  18. Simulation of an HTS Synchronous Superconducting Generator

    DEFF Research Database (Denmark)

    In this work we present a simulation of a synchronous generator with superconducting rotor windings. As many other electrical rotating machines, superconducting generators are exposed to ripple fields that could be produced from a wide variety of sources: short circuit, load change, etc. Unlike...... regular conductors, superconductors, experience high losses when exposed to AC fields. Thus, calculation of such losses is relevant for machine design to avoid quenches and increase performance. Superconducting coated conductors are well known to exhibit nonlinear resistivity, thus making the computation...... of heating losses a cumbersome task. Furthermore, the high aspect ratio of the superconducting materials involved adds a penalty in the time required to perform simulations. The chosen strategy for simulation is as follows: A mechanical torque signal together with an electric load is used to drive the finite...

  19. Simulation of an HTS Synchronous Superconducting Generator

    DEFF Research Database (Denmark)

    Rodriguez Zermeno, Victor Manuel; Abrahamsen, Asger Bech; Mijatovic, Nenad

    2012-01-01

    In this work we present a simulation of a synchronous generator with superconducting rotor windings. As many other,electrical rotating machines, superconducting generators are exposed to ripple fields that could be produced from a wide variety of sources: short circuit, load change, mechanical...... torque fluctuations, etc. Unlike regular conductors, superconductors, experience high losses when exposed to AC fields. Thus, calculation of such losses is relevant for machine design to avoid quenches and increase performance. Superconducting coated conductors are well known to exhibit nonlinear...... resistivity, thus making the computation of heating losses a cumbersome task. Furthermore, the high aspect ratio of the superconducting materials involved adds a penalty in the time required to perform simulations. The chosen strategy for simulation is as follows: A mechanical torque signal together...

  20. Large area bulk superconductors

    Science.gov (United States)

    Miller, Dean J.; Field, Michael B.

    2002-01-01

    A bulk superconductor having a thickness of not less than about 100 microns is carried by a polycrystalline textured substrate having misorientation angles at the surface thereof not greater than about 15.degree.; the bulk superconductor may have a thickness of not less than about 100 microns and a surface area of not less than about 50 cm.sup.2. The textured substrate may have a thickness not less than about 10 microns and misorientation angles at the surface thereof not greater than about 15.degree.. Also disclosed is a process of manufacturing the bulk superconductor and the polycrystalline biaxially textured substrate material.

  1. Superconductor terahertz metamaterial

    CERN Document Server

    Gu, Jianqiang; Tian, Zhen; Cao, Wei; Xing, Qirong; Han, Jiaguang; Zhang, Weili

    2010-01-01

    We characterize the behaviour of split ring resonators made up of high-transition temperature YBCO superconductor using terahertz time domain spectroscopy. The superconductor metamaterial shows sharp change in the transmission spectrum at the fundamental inductive-capacitive resonance and the dipole resonance as the temperature dips below the transition temperature. Our results reveal that the high performance of such a metamaterial is limited by material imperfections and defects such as cracks, voids and secondary phases which play dominant role in partially impeding the flow of current causing dissipation of energy and electrical resistance to appear in the superconductor film.

  2. Effect of different uranium compounds on the properties of U-Pt-Y-Ba-O double-perovskite pinning centres in textured Y-Ba-Cu-O superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Sawh, Ravi-Persad; Weinstein, Roy; Parks, Drew; Gandini, Alberto [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States); Department of Physics, University of Houston, Houston, TX 77204-5005 (United States); Texas Center for Superconductivity and Advanced Materials, University of Houston, Houston, TX 77204-5005 (United States)

    2005-02-01

    An experiment was performed to test the effect of different uranium compounds on the properties of chemical pinning centres. UO{sub 2}, UO{sub 3}, and UO{sub 4}{center_dot}2H{sub 2}O wereadmixed to Y 123+Pt, and textured. Tests of J{sub c} via measurements of trapped field (B{sub trap}) indicate a clear dependence of B{sub trap} on the U compound admixed to create the pinning centres. In all three cases there is a monotonic increase in B{sub trap} as the mass (M{sub U}) of U is increased. However, the magnitude of the increase in B{sub trap} depends on the admixed U compound. The highest increase in B{sub trap} is measured in samples doped with UO{sub 4}{center_dot}2H{sub 2}O, and the lowest is obtained in samples doped with UO{sub 2}. Microstructure studies indicate that the composition of the U-rich pinning deposits is the same in all three cases, i.e. all are the previously identified (U{sub 0.6}Pt{sub 0.4})Y Ba{sub 2}O{sub 6} compound. The primary difference among the three types of samples is that the size of the U-Pt-Y-Ba-O pinning deposits depends on the admixed U compound. While all are in the nanometre domain, the diameter of these deposits was markedly larger in UO{sub 2} doped samples than in UO{sub 3} doped samples, and smallest in UO{sub 4}{center_dot}2H{sub 2}O doped samples. Because some form of poisoning limits the amount of U that can be added to create pinning centres, to M{sub U} {approx}1 wt%, smaller deposits result in a greater number of pinning centres. We conclude that UO{sub 4}{center_dot}2H{sub 2}O is more effective than either UO{sub 3} or UO{sub 2} in the formation of U-Pt-Y-Ba-O pinning centres because of diminished pinning centre size, and consequent increase in pinning centre density.

  3. Development of superconductor bulk for superconductor bearing

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chan Joong; Jun, Byung Hyuk; Park, Soon Dong (and others)

    2008-08-15

    Current carrying capacity is one of the most important issues in the consideration of superconductor bulk materials for engineering applications. There are numerous applications of Y-Ba-Cu-O (YBCO) bulk superconductors e.g. magnetic levitation train, flywheel energy storage system, levitation transportation, lunar telescope, centrifugal device, magnetic shielding materials, bulk magnets etc. Accordingly, to obtain YBCO materials in the form of large, single crystals without weak-link problem is necessary. A top seeded melt growth (TSMG) process was used to fabricate single crystal YBCO bulk superconductors. The seeded and infiltration growth (IG) technique was also very promising method for the synthesis of large, single-grain YBCO bulk superconductors with good superconducting properties. 5 wt.% Ag doped Y211 green compacts were sintered at 900 .deg. C {approx} 1200 .deg.C and then a single crystal YBCO was fabricated by an infiltration method. A refinement and uniform distribution of the Y211 particles in the Y123 matrix were achieved by sintering the Ag-doped samples. This enhancement of the critical current density was ascribable to a fine dispersion of the Y211 particles, a low porosity and the presence of Ag particles. In addition, we have designed and manufactured large YBCO single domain with levitation force of 10-13 kg/cm{sup 2} using TSMG processing technique.

  4. Isotope and multiband effects in layered superconductors.

    Science.gov (United States)

    Bussmann-Holder, Annette; Keller, Hugo

    2012-06-13

    In this review we consider three classes of superconductors, namely cuprate superconductors, MgB(2) and the new Fe based superconductors. All of these three systems are layered materials and multiband compounds. Their pairing mechanisms are under discussion with the exception of MgB(2), which is widely accepted to be a 'conventional' electron-phonon interaction mediated superconductor, but extending the Bardeen-Cooper-Schrieffer (BCS) theory to account for multiband effects. Cuprates and Fe based superconductors have higher superconducting transition temperatures and more complex structures. Superconductivity is doping dependent in these material classes unlike in MgB(2) which, as a pure compound, has the highest values of T(c) and a rapid suppression of superconductivity with doping takes place. In all three material classes isotope effects have been observed, including exotic ones in the cuprates, and controversial ones in the Fe based materials. Before the area of high-temperature superconductivity, isotope effects on T(c) were the signature for phonon mediated superconductivity-even when deviations from the BCS value to smaller values were observed. Since the discovery of high T(c) materials this is no longer evident since competing mechanisms might exist and other mediating pairing interactions are discussed which are of purely electronic origin. In this work we will compare the three different material classes and especially discuss the experimentally observed isotope effects of all three systems and present a rather general analysis of them. Furthermore, we will concentrate on multiband signatures which are not generally accepted in cuprates even though they are manifest in various experiments, the evidence for those in MgB(2), and indications for them in the Fe based compounds. Mostly we will consider experimental data, but when possible also discuss theoretical models which are suited to explain the data.

  5. Fixed-frequency and Frequency-agile (au, HTS) Microstrip Bandstop Filters for L-band Applications

    Science.gov (United States)

    Saenz, Eileen M.; Subramanyam, Guru; VanKeuls, Fred W.; Chen, Chonglin; Miranda, Felix A.

    2001-01-01

    In this work, we report on the performance of a highly selective, compact 1.83 x 2.08 cm(exp 2) (approx. 0.72 x 0.82 in(exp 2) microstrip line bandstop filter of YBa2CU3O(7-delta) (YBCO) on LaAlO3 (LAO) substrate. The filter is designed for a center frequency of 1.623 GHz for a bandwidth at 3 dB from reference baseline of less than 5.15 MHz, and a bandstop rejection of 30 dB or better. The design and optimization of the filter was performed using Zeland's IE3D circuit simulator. The optimized design was used to fabricate gold (Au) and High-Temperature Superconductor (HTS) versions of the filter. We have also studied an electronically tunable version of the same filter. Tunability of the bandstop characteristics is achieved by the integration of a thin film conductor (Au or HTS) and the nonlinear dielectric ferroelectric SrTiO3 in a conductor/ferroelectric/dielectric modified microstrip configuration. The performance of these filters and comparison with the simulated data will be presented.

  6. Preparation of high-quality HTS rings for application in the magnetic bearing of cryotanks and pinning in grain boundaries

    Science.gov (United States)

    Bringmann, B.; Walter, H.; Jooss, Ch.; Leenders, A.; Freyhardt, H. C.

    2002-08-01

    Seeded melt growth of YBCO high-temperature superconductors is one of the most promising preparation techniques to obtain high-quality HTS tiles for application, e.g. in magnetic bearings. Semi-finished HTSL products of complex shapes have to be developed by different seeding and multi-seeding techniques. To obtain large hollow cylinders designed for application in the magnetic bearing of a cryotank a modified multi-seeded melt growth (MSMG) process was employed. This cryotank will be mounted for testing in a vehicle of a major German car manufacturer. The MSMG process introduces grain boundaries into the HTS tiles. For transport current investigations of [0 0 1]-tilt grain boundaries in melt textured YBCO a series of MSMG bicrystals have been prepared. They exhibit a dependence of the critical current density on misorientation angle which is much weaker than the one observed in thin-film bicrystals. The bulk samples have dimensions larger than the magnetic penetration depth along the grain boundary. Thus, flux pinning has to be taken into account. Different contributions to the longitudinal pinning force have to be considered: vortices at grain boundaries can be pinned by magnetic interaction with Abrikosov vortices in the banks, by defects in the grain boundary itself or by defects which are located next to the grain boundary.

  7. Modelling ac ripple currents in HTS coated conductors

    Science.gov (United States)

    Xu, Zhihan; Grilli, Francesco

    2015-10-01

    Dc transmission using high temperature superconducting (HTS) coated conductors (CCs) offers a promising solution to the globally growing demand for effective, reliable and economic transmission of green energy up to the gigawatt level over very long distances. The credible estimation of the losses and thereby the heat dissipation involved, where ac ripples (introduced in rectification/ac-dc conversion) are viewed as a potential source of notable contribution, is highly essential for the rational design of practical HTS dc transmission cables and corresponding cryogenic systems to fulfil this demand. Here we report a targeted modelling study into the ac losses in a HTS CC subject to dc and ac ripple currents simultaneously, by solving Maxwell’s equations using the finite element method (FEM) in the commercial software package COMSOL. It is observed that the instantaneous loss exhibits only one peak per cycle in the HTS CC subject to sinusoidal ripples, given that the amplitude of the ac ripples is smaller than approximately 20% of that of the dc current. This is a distinct contrast to the usual observation of two peaks per cycle in a HTS CC subject to ac currents only. The unique mechanism is also revealed, which is directly associated with the finding that, around any local minima of the applied ac ripples, the critical state of -J c is never reached at the edges of the HTS CC, as it should be according to the Bean model. When running further into the longer term, it is discovered that the ac ripple loss of the HTS CC in full-wave rectification decays monotonically, at a speed which is found to be insensitive to the frequency of the applied ripples within our targeted situations, to a relatively low level of approximately 1.38 × 10-4 W m-1 in around 1.7 s. Comparison between this level and other typical loss contributions in a HTS dc cable implies that ac ripple currents in HTS CCs should only be considered as a minor source of dissipation in superconducting dc

  8. Heat Transfer Experiments and Analysis of a Simulated HTS

    Energy Technology Data Exchange (ETDEWEB)

    Demko, Jonathan A [ORNL; Duckworth, Robert C [ORNL; Gouge, Michael J [ORNL; Knoll, David [Ultera – A Southwire / nkt cables Joint Venture

    2010-01-01

    Long-length high temperature superconducting (HTS) cable projects, over 1 km, are being designed that are cooled by flowing liquid nitrogen. The compact counter-flow cooling arrangement which has the supply and return stream in a single cryostat offers several advantages including smallest space requirement, least heat load, and reduced cost since a return cryostat is not required. One issue in long length HTS cable systems is the magnitude of the heat transfer radially through the cable. It is extremely difficult to instrument an HTS cable in service on the grid with the needed thermometry because of the issues associated with installing thermometers on high voltage components. A 5-meter long test system has been built that simulates a counter-flow cooled, HTS cable using a heated tube to simulate the cable. Measurements of the temperatures in the flow stream and on the tube wall are presented and compared to analysis. These data can be used to benchmark different HTS cable heat transfer and fluid flow analysis approaches.

  9. Magnetic characterisation of large grain, bulk Y-Ba-Cu-O superconductor-soft ferromagnetic alloy hybrid structures

    Science.gov (United States)

    Philippe, M. P.; Fagnard, J.-F.; Kirsch, S.; Xu, Z.; Dennis, A. R.; Shi, Y.-H.; Cardwell, D. A.; Vanderheyden, B.; Vanderbemden, P.

    2014-07-01

    Large grain, bulk Y-Ba-Cu-O (YBCO) high temperature superconductors (HTS) have significant potential for use in a variety of practical applications that incorporate powerful quasi-permanent magnets. In the present work, we investigate how the trapped field of such magnets can be improved by combining bulk YBCO with a soft FeNi, ferromagnetic alloy. This involves machining the alloy into components of various shapes, such as cylinders and rings, which are attached subsequently to the top surface of a solid, bulk HTS cylinder. The effect of these modifications on the magnetic hysteresis curve and trapped field of the bulk superconductor at 77 K are then studied using pick-up coil and Hall probe measurements. The experimental data are compared to finite element modelling of the magnetic flux distribution using Campbell’s algorithm. Initially we establish the validity of the technique involving pick-up coils wrapped around the bulk superconductor to obtain its magnetic hysteresis curve in a non-destructive way and highlight the difference between the measured signal and the true magnetization of the sample. We then consider the properties of hybrid ferromagnet/superconductor (F/S) structures. Hall probe measurements, together with the results of the model, establish that flux lines curve outwards through the ferromagnet, which acts, effectively, like a magnetic short circuit. Magnetic hysteresis curves show that the effects of the superconductor and the ferromagnet simply add when the ferromagnet is saturated fully by the applied field. The trapped field of the hybrid structure is always larger than that of the superconductor alone below this saturation level, and especially when the applied field is removed. The results of the study show further that the beneficial effects on the trapped field are enhanced when the ferromagnet covers the entire surface of the superconductor for different ferromagnetic components of various shapes and fixed volume.

  10. Electrodynamics of Metallic Superconductors

    Directory of Open Access Journals (Sweden)

    M. Dressel

    2013-01-01

    Full Text Available The theoretical and experimental aspects of the microwave, terahertz, and infrared properties of superconductors are discussed. Electrodynamics can provide information about the superconducting condensate as well as about the quasiparticles. The aim is to understand the frequency dependence of the complex conductivity, the change with temperature and time, and its dependence on material parameters. We confine ourselves to conventional metallic superconductors, in particular, Nb and related nitrides and review the seminal papers but also highlight latest developments and recent experimental achievements. The possibility to produce well-defined thin films of metallic superconductors that can be tuned in their properties allows the exploration of fundamental issues, such as the superconductor-insulator transition; furthermore it provides the basis for the development of novel and advanced applications, for instance, superconducting single-photon detectors.

  11. Topological superconductors: a review.

    Science.gov (United States)

    Sato, Masatoshi; Ando, Yoichi

    2017-04-03

    This review elaborates pedagogically on the fundamental concept, basic theory, expected properties, and materials realizations of topological superconductors. The relation between topological superconductivity and Majorana fermions are explained, and the difference between dispersive Majorana fermions and a localized Majorana zero mode is emphasized. A variety of routes to topological superconductivity are explained with an emphasis on the roles of spin-orbit coupling. Present experimental situations and possible signatures of topological superconductivity are summarized with an emphasis on intrinsic topological superconductors.

  12. Layered nickel based superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Ronning, Filip [Los Alamos National Laboratory; Bauer, Eric D [Los Alamos National Laboratory; Park, Tuson [Los Alamos National Laboratory; Kurita, Nobuyuki [Los Alamos National Laboratory; Klimczuk, T [Los Alamos National Laboratory; Movshovich, R [Los Alamos National Laboratory; Thompson, J D [Los Alamos National Laboratory; Sefat, A S [ORNL; Mandrus, D [ORNL

    2009-01-01

    We review the properties of Ni-based superconductors which contain Ni{sub 2}X{sub 2} (X=As, P, Bi, Si, Ge, B) planes, a common structural element to the recently discovered FeAs superconductors. We also compare the properties ofthe Ni-and Fe-based systems from a perspective ofelectronic structure as well as structure-property relations.

  13. Electronic structure investigation of novel superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Buling, Anna

    2014-05-15

    The discovery of superconductivity in iron-based pnictides in 2008 gave rise to a high advance in the research of high-temperature superconductors. But up to now there is no generally admitted theory of the non-BCS mechanism of these superconductors. The electron and hole doped Ba122 (BaFe{sub 2}As{sub 2}) compounds investigated in this thesis are supposed to be suitable model systems for studying the electronic behavior in order to shed light on the superconducting mechanisms. The 3d-transition metal doped Ba122 compounds are investigated using the X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), X-ray emission spectroscopy (XES) and X-ray magnetic circular dichroism (XMCD), while the completely hole doped K122 is observed using XPS. The experimental measurements are complemented by theoretical calculations. A further new class of superconductors is represented by the electride 12CaO*7Al{sub 2}O{sub 3}: Here superconductivity can be realized by electrons accommodated in the crystallographic sub-nanometer-sized cavities, while the mother compound is a wide band gap insulator. Electronic structure investigations, represented by XPS, XAS and resonant X-ray photoelectron spectroscopy (ResPES), carried out in this work, should help to illuminate this unconventional superconductivity and resolve a debate of competing models for explaining the existence of superconductivity in this compound.

  14. Continuous lengths of oxide superconductors

    Science.gov (United States)

    Kroeger, Donald M.; List, III, Frederick A.

    2000-01-01

    A layered oxide superconductor prepared by depositing a superconductor precursor powder on a continuous length of a first substrate ribbon. A continuous length of a second substrate ribbon is overlaid on the first substrate ribbon. Sufficient pressure is applied to form a bound layered superconductor precursor powder between the first substrate ribbon and the second substrate ribbon. The layered superconductor precursor is then heat treated to establish the oxide superconducting phase. The layered oxide superconductor has a smooth interface between the substrate and the oxide superconductor.

  15. Structural Parameter Optimization of Multilayer Conductors in HTS Cable

    Institute of Scientific and Technical Information of China (English)

    Yan Mao; Jie Qiu; Xin-Ying Liu; Zhi-Xuan Wang; Shu-Hong Wang; Jian-Guo Zhu; You-Guang Guo; Zhi-Wei Lin; Jian-Xun Jin

    2008-01-01

    In this paper, the design optimization of the structural parameters of multilayer conductors in high temperature superconducting (HTS) cable is reviewed. Various optimization methods, such as the particle swarm optimization (PSO), the genetic algorithm (GA), and a robust optimization method based on design for six sigma (DFSS), have been applied to realize uniform current distribution among the multi- layer HTS conductors. The continuous and discrete variables, such as the winding angle, radius, and winding direction of each layer, are chosen as the design parameters. Under the constraints of the mechanical properties and critical current, PSO is proven to be a more powerful tool than GA for structural parameter optimization, and DFSS can not only achieve a uniform current distribution, but also improve significantly the reliability and robustness of the HTS cable quality.

  16. Levitation force relaxation under reloading in a HTS Maglev system

    Science.gov (United States)

    He, Qingyong; Wang, Jiasu; Wang, Suyu; Wang, Jiansi; Dong, Hao; Wang, Yuxin; Shao, Senhao

    2009-02-01

    The loading capacity of the high-temperature superconducting (HTS) Maglev vehicle is an important parameter in the practical application. It is closely related to the levitation force of the HTS bulk. Many papers reported that the levitation force showed the relaxation characteristic. Because different loads cause different levitation gaps and different applied magnetic fields, the levitation force relaxations under the different loads are not the same. In terms of cylindrical YBCO bulk levitated over the permanent magnetic guideway, the relationship between the levitation force relaxation and the reloading is investigated experimentally in this paper. The decrement, the decrement rate and the relaxation rate of the levitation force are calculated, respectively. This work might be helpful for studying the loading capacity of the HTS Maglev vehicle.

  17. Generador Eólico Superconductor Superconducting Wind Synchronous Generator

    Directory of Open Access Journals (Sweden)

    A Leão Rodrigues

    2010-01-01

    Full Text Available En este artículo se presentan las propiedades de los materiales superconductores de alta temperatura (SAT en la construcción de máquinas eléctricas. Se describe un generador sincrónico con configuración en disco con una elevada potencia específica, para futuras aplicaciones de energía. El generador es excitado por medio de bloques de materiales cerámicos SAT y se explica el mecanismo para atrapar el flujo magnético en ellos. El sistema criogénico está formado por un contenedor de nitrógeno líquido localizado en el suelo de forma a reducir el peso sobre la torre. Se presenta el grafico del flujo magnético por dos polos de la maquina, calculado por medio del método de los elementos finitos, así como la distribución de la densidad de flujo en el entrehierro del generador superconductor en disco. Se propone un parque eólico de elevado rendimiento con este tipo de generadores.This paper presents the properties of high temperature superconductor (HTS materials in the construction of electrical machines. A disc type configuration synchronous generator with high specific power for future wind power applications is described. The generator is excited by means blocks of HTS ceramic materials. The mechanism to trap the magnetic flux in HTS blocks is explained. To decrease the weight of the generator on the top of the tower, the cryogenic system used consists of a liquid nitrogen storage container located on the ground to reduce weight on the tower. A flux plot per two poles of the machine calculated using the finite element method is presented and the flux density distribution in the air gap of the superconducting disc generator is also displayed. A high efficiency wind park with this type of generators is proposed.

  18. Lightweight Design of an HTS Coil for the VASIMR Experiment Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Tai-Yang Research of Delaware proposes to design and fabricate an HTS double-pancake coil in support of the VASIMR experiment. The proposed HTS coil will implement...

  19. Design aspects of mid-size SMES using high temperature superconductors

    Science.gov (United States)

    Schoenung, S. M.; Meier, W. R.; Hull, J. R.; Fagaly, R. L.; Heiberger, M.; Stephens, R. B.; Leuer, J. A.; Guzman, R. A.

    1992-08-01

    Conceptual designs of modular, cold-supported SMES units using high temperature superconductors (HTS) were investigated over the mid-size energy range of 2 to 200 MWh (7.2 to 720 GJ). This size range covers many utility, industrial, and military applications. Both toroidal and solenoidal configurations were analyzed to determine physical dimensions, heat loads, and cost of major components. Among the effects considered were the impact of critical current density on feasible configurations, mass of conductor, and cost; the effects of magnetic field and strain limits on physical parameters and structural mass; and the savings in refrigeration from operating at high temperature. The design of the HTS conductor, stability criteria, and coolant selection are also discussed.

  20. Coasting characteristic of the flywheel system under anisotropy effect of bulk high temperature superconductors

    Science.gov (United States)

    Wu, J. F.; Li, Y.

    2014-10-01

    High-temperature superconductors (HTSCs) array with aligned growth section boundary (GSB) pattern (AGSBP) exhibits larger levitation force and suppression of levitation force decay above a permanent magnet guideway (PMG) compared with misaligned GSB pattern (MGSBP) has been studied in maglev train application (Zheng et al., 2013). This result maybe helpful and support a new way for the HTS bearing design for flywheel systems. So, in this paper, we further examine this growth anisotropy effect on the maglev performance of flywheel system. Levitation force and coasting time were investigated from the point-view of HTS flywheel applications. The GS/GSB alignment of AGSBP bulk HTSCs produces larger levitation force than that of MGSBP, but the coasting time is shorter than that of MGSBP, that is to say, the electric magnetic drag force with AGSBP is larger than that of MGSBP. This result may also exist in the maglev guideline when the maglev train stops freely.

  1. Specimen preparation and atom probe field ion microscopy of BSCCO-2212 superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Larson, D.J. [Wisconsin Univ., Madison, WI (United States). Mater. Sci. Program]|[Applied Superconductivity Center, Univ. of Wisconsin, Madison, WI (United States); Camus, P.P. [Applied Superconductivity Center, Univ. of Wisconsin, Madison, WI (United States)]|[Wisconsin Univ., Madison, WI (United States). Dept. of Materials Sciences and Engineering; Vargas, J.L. [Applied Superconductivity Center, Univ. of Wisconsin, Madison, WI (United States); Kelly, T.F. [Wisconsin Univ., Madison, WI (United States). Mater. Sci. Program]|[Applied Superconductivity Center, Univ. of Wisconsin, Madison, WI (United States)]|[Wisconsin Univ., Madison, WI (United States). Dept. of Materials Sciences and Engineering; Miller, M.K. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1996-09-01

    Field ion specimens of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub x} (BSCCO) high temperature superconductor (HTS) materials have been prepared using a combination of three different preparation techniques: the method of sharp shards, electropolishing and ion milling. Field ion microscopy (FIM) has demonstrated that samples which exhibit the ``striped``-image contrast characteristic of HTS materials can be successfully fabricated using this combination. FIM images have been obtained which show the striped-image contrast much clearer than any previously published images of Pb-free BSCCO. Preliminary atom probe (AP) chemical analysis of the material was also performed. Analytical electron microscopy was used to confirm the existence of both the correct crystallographic structure and nominal composition in the near-apex region of the specimen after preparation and FIM. (orig.).

  2. Experimental study of high-temperature superconductor shield for electron cooling system

    Science.gov (United States)

    Smirnov, A.; Dorofeev, G.; Drobin, V.; Kulikov, E.; Malinovski, H.

    2016-12-01

    The NICA project includes a system of electron cooling for charged particle beams for total ion energy of 4.5 GeV/n. To achieve the required cooling time, the magnetic field homogeneity in the cooling section should be at least 10-5 for a solenoid length in the cooling system of about 6 m. The cost of such solenoid, however, is very high due to the complexity of high-precision winding. The application of the superconducting shield could help to resolve this problem. In this study we present the results of an experimental investigation of the prototype of the shield manufactured from high-temperature superconductor (HTS) tapes. The measurements were performed at different quasistationary operating conditions. The requirements for the HTS shield and solenoid parameters are formulated.

  3. Protein crystallization: from HTS to kilogram-scale.

    Science.gov (United States)

    Klyushnichenko, Vadim

    2003-11-01

    The first experiments on protein crystallization started randomly during the 19th century. This technique has been widely used for the determination of the tertiary structure of proteins since the 1950s, when an understanding of the physics of protein crystallization began to emerge. In the 1980s and 1990s, research focused on the study of protein crystal growth processes in microgravity environments, which were created in space shuttle experiments. High-throughput screening (HTS) systems were developed that later found broader laboratory applications. The combination of HTS with an engineering approach opens new opportunities for the protein crystallization process to become a robust, scalable, reproducible and economically viable industrial unit operation.

  4. Study of HTS Wires at High Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Turrioni, D.; Barzi, E.; Lamm, M.J.; Yamada, R.; Zlobin, A.V.; Kikuchi, A.; /Fermilab

    2009-01-01

    Fermilab is working on the development of high field magnet systems for ionization cooling of muon beams. The use of high temperature superconducting (HTS) materials is being considered for these magnets using Helium refrigeration. Critical current (I{sub c}) measurements of HTS conductors were performed at FNAL and at NIMS up to 28 T under magnetic fields at zero to 90 degree with respect to the sample face. A description of the test setups and results on a BSCCO-2223 tape and second generation (2G) coated conductors are presented.

  5. Design and manufacture of a D-shape coil-based toroid-type HTS DC reactor using 2nd generation HTS wire

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kwangmin, E-mail: kwangmin81@gmail.com [Changwon National University, 55306 Sarim-dong, Changwon 641-773 (Korea, Republic of); Go, Byeong-Soo; Sung, Hae-Jin; Park, Hea-chul; Kim, Seokho [Changwon National University, 55306 Sarim-dong, Changwon 641-773 (Korea, Republic of); Lee, Sangjin [Uiduk University, Gyeongju 780-713 (Korea, Republic of); Jin, Yoon-Su; Oh, Yunsang [Vector Fields Korea Inc., Pohang 790-834 (Korea, Republic of); Park, Minwon [Changwon National University, 55306 Sarim-dong, Changwon 641-773 (Korea, Republic of); Yu, In-Keun, E-mail: yuik@changwon.ac.kr [Changwon National University, 55306 Sarim-dong, Changwon 641-773 (Korea, Republic of)

    2014-09-15

    Highlights: • The authors designed and fabricated a D-shape coil based toroid-type HTS DC reactor using 2G GdBCO HTS wires. • The toroid-type magnet consisted of 30 D-shape double pancake coil (DDC)s. The total length of the wire was 2.32 km. • The conduction cooling method was adopted for reactor magnet cooling. • The maximum cooling temperature of reactor magnet is 5.5 K. • The inductance was 408 mH in the steady-state condition (300 A operating). - Abstract: This paper describes the design specifications and performance of a real toroid-type high temperature superconducting (HTS) DC reactor. The HTS DC reactor was designed using 2G HTS wires. The HTS coils of the toroid-type DC reactor magnet were made in the form of a D-shape. The target inductance of the HTS DC reactor was 400 mH. The expected operating temperature was under 20 K. The electromagnetic performance of the toroid-type HTS DC reactor magnet was analyzed using the finite element method program. A conduction cooling method was adopted for reactor magnet cooling. Performances of the toroid-type HTS DC reactor were analyzed through experiments conducted under the steady-state and charge conditions. The fundamental design specifications and the data obtained from this research will be applied to the design of a commercial-type HTS DC reactor.

  6. Development of Stable, Low Resistance Solder Joints for a Space-Flight HTS Lead Assemblies

    Science.gov (United States)

    Canavan, Edgar R.; Chiao, Meng; Panashchenko, Lyudmyla; Sampson, Michael

    2017-01-01

    The solder joints in spaceflight high temperature superconductor (HTS) lead assemblies for certain astrophysics missions have strict constraints on size and power dissipation. In addition, the joints must tolerate years of storage at room temperature, many thermal cycles, and several vibration tests between their manufacture and their final operation on orbit. As reported previously, solder joints between REBCO coated conductors and normal metal traces for the Astro-H mission showed low temperature joint resistance that grew approximately as log time over the course of months. Although the assemblies worked without issue in orbit, for the upcoming X-ray Astrophysics Recovery Mission we are attempting to improve our solder process to give lower, more stable, and more consistent joint resistance. We produce numerous sample joints and measure time- and thermal cycle-dependent resistance, and characterize the joints using x-ray and other analysis tools. For a subset of the joints, we use SEMEDS to try to understand the physical and chemical processes that effect joint behavior.

  7. A Simplified Model to Calculate AC Losses in Large 2G HTS Coils

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Mijatovic, Nenad; Jensen, Bogi Bech;

    2015-01-01

    AC losses are of great significance to quantify the performance of high temperature superconducting (HTS) devices. This paper presents a simplified model to calculate AC losses in large 2G HTS coils, which serves as a baseline to study HTS large scale applications such as electric machines. The m...

  8. Synthesis and SAR of novel, 4-(phenylsulfamoyl)phenylacetamide mGlu4 positive allosteric modulators (PAMs) identified by functional high-throughput screening (HTS).

    Science.gov (United States)

    Engers, Darren W; Gentry, Patrick R; Williams, Richard; Bolinger, Julie D; Weaver, C David; Menon, Usha N; Conn, P Jeffrey; Lindsley, Craig W; Niswender, Colleen M; Hopkins, Corey R

    2010-09-01

    Herein we disclose the synthesis and SAR of a series of 4-(phenylsulfamoyl)phenylacetamide compounds as mGlu(4) positive allosteric modulators (PAMs) that were identified via a functional HTS. An iterative parallel approach to these compounds culminated in the discovery of VU0364439 (11) which represents the most potent (19.8 nM) mGlu(4) PAM reported to date.

  9. Theoretical estimation of quench occurrence and propagation based on generalized thermoelasticity for LTS/HTS tapes triggered by a spot heater

    Science.gov (United States)

    Tong, Yujin; Guan, Mingzhi; Wang, Xingzhe

    2017-04-01

    The present study deals with the thermal characteristics and mechanical behaviors of low/high temperature superconducting (LTS/HTS) composite tapes during quench processes triggered by a spot heater. Based on the generalized thermoelastic theory, a dynamic thermoelastic model with a relaxation time is developed which takes into account the temperature dependence and finite speed of heat propagation for the superconducting tapes under cryogenic condition. The analyses were performed using the finite element method to solve the coupled differential equations of dynamic heat conduction and elastic equilibrium. The results show that the thermoelastic behaviors exhibit a strong relevance to quench characteristics of the superconductors. As a quench occurs, the thermoelastic strain-rate has an obvious jumping variation with the instant of time of its peak being fortunately coincident with the time at which the critical temperature is reached. Such a jumping change of strain-rate could be a way of estimation and detection of quench occurrence, and the theoretical predictions coincide with the existing experimental observations on thermoelastic strain-rate in LTS magnets. For a HTS tape, the thermoelastic strain-rate or temperature-rate variation and a small jump also are illustrated as the quench occurrence is determined. Additionally, the normal zone propagation velocities for the LTS/HTS tapes are predicted by the critical temperature and thermoelastic strain-rate to show quite good agreements with the results evaluated by Wilson’s formula for a LTS tape or the experimental measurements for a HTS tape. The influences of the relaxation time of heat conduction and thermoelastic coupling on the thermal distribution and strain profile are also discussed in details.

  10. Status and Progress of a Fault Current Limiting Hts Cable to BE Installed in the con EDISON Grid

    Science.gov (United States)

    Maguire, J.; Folts, D.; Yuan, J.; Henderson, N.; Lindsay, D.; Knoll, D.; Rey, C.; Duckworth, R.; Gouge, M.; Wolff, Z.; Kurtz, S.

    2010-04-01

    In the last decade, significant advances in the performance of second generation (2G) high temperature superconducting wire have made it suitable for commercially viable applications such as electric power cables and fault current limiters. Currently, the U.S. Department of Homeland Security is co-funding the design, development and demonstration of an inherently fault current limiting HTS cable under the Hydra project with American Superconductor and Consolidated Edison. The cable will be approximately 300 m long and is being designed to carry 96 MVA at a distribution level voltage of 13.8 kV. The underground cable will be installed and energized in New York City. The project is led by American Superconductor teamed with Con Edison, Ultera (Southwire and nkt cables joint venture), and Air Liquide. This paper describes the general goals, design criteria, status and progress of the project. Fault current limiting has already been demonstrated in 3 m prototype cables, and test results on a 25 m three-phase cable will be presented. An overview of the concept of a fault current limiting cable and the system advantages of this unique type of cable will be described.

  11. Fabrication of a high performance acoustic emission (AE) sensor to monitor and diagnose disturbances in HTS tapes and magnet systems

    Science.gov (United States)

    Kim, Ju-Hyung; Song, Jung-Bin; Jeong, Young Hun; Lee, Young-Jin; Paik, Jong-Hoo; Kim, Woo-Seok; Lee, Haigun

    2010-02-01

    An acoustic emission (AE) technique was introduced as a non-destructive method to monitor sudden deformation caused by local heat concentrations and micro-cracks within superconductors and superconducting magnets. However, the detection of AE signals in a high temperature superconductor (HTS) tape is not easy because of its low signal to noise ratio caused by the noise from boiling liquid cryogen or mechanical vibration from the cryo-cooler. Therefore, high performance piezoelectric ceramics are needed to improve the sensitivity of the AE sensor. The aim of this study was to improve the piezoelectric and dielectric properties to enhance the performance of an AE sensor. This study examined the effects of Nb2O5 addition (0.0 wt.% to 2.0 wt.%) on the properties of high performance piezoelectric ceramics, Pb(Zr0.54 Ti0.46)O3 + 0.2 wt.% Cr2O3, sintered at 1200 °C for 2 h. The performance was examined with respect to the acoustic emission response of AE sensors manufactured using the specimens with various Nb2O5 contents. Superior sensor performance was obtained for the AE sensors fabricated with the specimens containing 1.0 wt.% to 1.5 wt.% Nb2O5. The performance and characteristics of the AE sensors were in accordance with their piezoelectric and dielectric properties.

  12. Development of toroid-type HTS DC reactor series for HVDC system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kwangmin, E-mail: kwangmin81@gmail.com [Changwon National University, 55306 Sarim-dong, Changwon 641-773 (Korea, Republic of); Go, Byeong-Soo; Park, Hea-chul; Kim, Sung-kyu; Kim, Seokho [Changwon National University, 55306 Sarim-dong, Changwon 641-773 (Korea, Republic of); Lee, Sangjin [Uiduk University, Gyeongju 780-713 (Korea, Republic of); Oh, Yunsang [Vector Fields Korea Inc., Pohang 790-834 (Korea, Republic of); Park, Minwon; Yu, In-Keun [Changwon National University, 55306 Sarim-dong, Changwon 641-773 (Korea, Republic of)

    2015-11-15

    Highlights: • The authors developed the 400 mH, 400 A class toroid-type HTS DC reactor system. • The target temperature, inductance and operating current are under 20 K at magnet, 400 mH and 400 A, respectively. All target performances of the HTS DC reactor were achieved. • The HTS DC reactor was conducted through the interconnection operation with a LCC type HVDC system. • Now, the authors are studying the 400 mH, 1500 A class toroid-type HTS DC reactor for the next phase HTS DC reactor. - Abstract: This paper describes design specifications and performance of a toroid-type high-temperature superconducting (HTS) DC reactor. The first phase operation targets of the HTS DC reactor were 400 mH and 400 A. The authors have developed a real HTS DC reactor system during the last three years. The HTS DC reactor was designed using 2G GdBCO HTS wires. The HTS coils of the toroid-type DC reactor magnet were made in the form of a D-shape. The electromagnetic performance of the toroid-type HTS DC reactor magnet was analyzed using the finite element method program. A conduction cooling method was adopted for reactor magnet cooling. The total system has been successfully developed and tested in connection with LCC type HVDC system. Now, the authors are studying a 400 mH, kA class toroid-type HTS DC reactor for the next phase research. The 1500 A class DC reactor system was designed using layered 13 mm GdBCO 2G HTS wire. The expected operating temperature is under 30 K. These fundamental data obtained through both works will usefully be applied to design a real toroid-type HTS DC reactor for grid application.

  13. Granular Superconductors and Gravity

    Science.gov (United States)

    Noever, David; Koczor, Ron

    1999-01-01

    As a Bose condensate, superconductors provide novel conditions for revisiting previously proposed couplings between electromagnetism and gravity. Strong variations in Cooper pair density, large conductivity and low magnetic permeability define superconductive and degenerate condensates without the traditional density limits imposed by the Fermi energy (approx. 10(exp -6) g cu cm). Recent experiments have reported anomalous weight loss for a test mass suspended above a rotating Type II, YBCO superconductor, with a relatively high percentage change (0.05-2.1%) independent of the test mass' chemical composition and diamagnetic properties. A variation of 5 parts per 104 was reported above a stationary (non-rotating) superconductor. In experiments using a sensitive gravimeter, bulk YBCO superconductors were stably levitated in a DC magnetic field and exposed without levitation to low-field strength AC magnetic fields. Changes in observed gravity signals were measured to be less than 2 parts in 108 of the normal gravitational acceleration. Given the high sensitivity of the test, future work will examine variants on the basic magnetic behavior of granular superconductors, with particular focus on quantifying their proposed importance to gravity.

  14. Academic Training Lecture Regular Programme: Superconducting Magnets with HTS

    CERN Multimedia

    2012-01-01

    Superconducting Magnets with HTS (1/5), by Justin Schwartz (North Carolina State University).   Monday, June 25, 2012 from 11:00 to 12:00 (Europe/Zurich) at CERN ( 30-7-018 - Kjell Johnsen Auditorium ).   More information here.

  15. Calculation of AC losses in large HTS stacks and coils

    DEFF Research Database (Denmark)

    Zermeno, Victor; Abrahamsen, Asger Bech; Mijatovic, Nenad;

    2012-01-01

    In this work, we present a homogenization method to model a stack of HTS tapes under AC applied transport current or magnetic field. The idea is to find an anisotropic bulk equivalent for the stack of tapes, where the internal alternating structures of insulating, metallic, superconducting and su...

  16. HTS dc SQUID based rf amplifier: development concept

    DEFF Research Database (Denmark)

    Prokopenko, G.V.; Shitov, S.V.; Borisenko, I.V.;

    2002-01-01

    We present a concept of a rf amplifier based on a directly coupled dc SQUID with bicrystal junctions, which have high saturation power and can be used with SIS mixers or possibly for satellite and cellular phone communications. A novel input resonant circuit is proposed using single layer of HTS...

  17. Large-scale HTS bulks for magnetic application

    Science.gov (United States)

    Werfel, Frank N.; Floegel-Delor, Uta; Riedel, Thomas; Goebel, Bernd; Rothfeld, Rolf; Schirrmeister, Peter; Wippich, Dieter

    2013-01-01

    ATZ Company has constructed about 130 HTS magnet systems using high-Tc bulk magnets. A key feature in scaling-up is the fabrication of YBCO melts textured multi-seeded large bulks with three to eight seeds. Except of levitation, magnetization, trapped field and hysteresis, we review system engineering parameters of HTS magnetic linear and rotational bearings like compactness, cryogenics, power density, efficiency and robust construction. We examine mobile compact YBCO bulk magnet platforms cooled with LN2 and Stirling cryo-cooler for demonstrator use. Compact cryostats for Maglev train operation contain 24 pieces of 3-seed bulks and can levitate 2500-3000 N at 10 mm above a permanent magnet (PM) track. The effective magnetic distance of the thermally insulated bulks is 2 mm only; the stored 2.5 l LN2 allows more than 24 h operation without refilling. 34 HTS Maglev vacuum cryostats are manufactured tested and operate in Germany, China and Brazil. The magnetic levitation load to weight ratio is more than 15, and by group assembling the HTS cryostats under vehicles up to 5 t total loads levitated above a magnetic track is achieved.

  18. Modelling, Construction, and Testing of a Simple HTS Machine Demonstrator

    DEFF Research Database (Denmark)

    Jensen, Bogi Bech; Abrahamsen, Asger Bech

    2011-01-01

    This paper describes the construction, modeling and experimental testing of a high temperature superconducting (HTS) machine prototype employing second generation (2G) coated conductors in the field winding. The prototype is constructed in a simple way, with the purpose of having an inexpensive w...

  19. Model and Simulation of a HTS Generator under transient response

    DEFF Research Database (Denmark)

    Rodriguez Zermeno, Victor Manuel; Abrahamsen, Asger Bech; Mijatovic, Nenad

    2012-01-01

    Use of HTS field windings in electrical rotating machines can increase the torque density by a factor of 2-3 compared to conventional designs. This is highly attractive for large scale applications, such as ship propulsion and wind turbines. However, design considerations have to take into account...

  20. Potential impact of high temperature superconductors on maglev transportation

    Energy Technology Data Exchange (ETDEWEB)

    Hull, J.R.

    1992-02-01

    This report describes the potential impact that high-temperature superconductors (HTSs) may have on transportation by magnetically levitated vehicles. It is not intended as a planning document, but rather as an overview of potential HTS applications to magnetic-levitation (maglev) transportation. The present maglev program in the United States is summarized, and the present status of development of HTSs is described. Areas identified for possible impact on maglev technology are (1) liquid-nitrogen-cooled levitation magnets, (2) magnetic-field shielding of the passenger compartment, (3) superconducting magnetic energy storage for wayside power, (4) superconducting bearings for flywheel energy storage for wayside power, (5) downleads to continuously powered liquid-helium-cooled levitation magnets, and (6) liquid-hydrogen-cooled levitation magnets and linear motor propulsion windings. Major technical issues that remain to be resolved for the use of HTSs in maglev applications include thermal magnetic stability, mechanical properties, and critical current density at liquid-nitrogen temperatures.

  1. Coil Optimization for High Temperature Superconductor Machines

    DEFF Research Database (Denmark)

    Mijatovic, Nenad; Jensen, Bogi Bech; Abrahamsen, Asger Bech

    2011-01-01

    This paper presents topology optimization of HTS racetrack coils for large HTS synchronous machines. The topology optimization is used to acquire optimal coil designs for the excitation system of 3 T HTS machines. Several tapes are evaluated and the optimization results are discussed. The optimiz...

  2. Moessbauer studies of ternary superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kimball, C.W.; Van Landuyt, G.L.; Barnet, C.D.; Shenoy, G.K.; Dunlap, B.D.; Fradin, F.Y.

    1978-01-01

    Moessbauer studies of the ternary Chevrel phase and rare earth rhodium boride superconductors have been made. Anomalous phonon properties at the Sn site in SnMo/sub 6/S/sub 8/, SnMo/sub 6/Se/sub 8/, and La/sub 0/ /sub 98/Sn/sub 0/ /sub 02/Mo/sub 6/Se/sub 8/ have been investigated. Studies of polarization of conduction electrons at the site of the magnetic ion have been made by means of the /sup 151/Eu Moessbauer effect in Eu/sub x/Sn/sub 1-x/Mo/sub 6/S/sub 8/ and the effects of such polarization on superconducting properties discussed. The Moessbauer effect in /sup 166/Er has been used to investigate the electronic ground state in the ternary compound ErRh/sub 4/B/sub 4/ both in the superconducting and magnetically ordered states.

  3. Lightning in superconductors.

    Science.gov (United States)

    Vestgården, J I; Shantsev, D V; Galperin, Y M; Johansen, T H

    2012-01-01

    Crucially important for application of type-II superconductor films is the stability of the vortex matter--magnetic flux lines penetrating the material. If some vortices get detached from pinning centres, the energy dissipated by their motion will facilitate further depinning, and may trigger a massive electromagnetic breakdown. Up to now, the time-resolved behaviour of these ultra-fast events was essentially unknown. We report numerical simulation results revealing the detailed dynamics during breakdown as within nanoseconds it develops branching structures in the electromagnetic fields and temperature, with striking resemblance of atmospheric lightning. During a dendritic avalanche the superconductor is locally heated above its critical temperature, while electrical fields rise to several kV/m as the front propagates at instant speeds near up to 100 km/s. The numerical approach provides an efficient framework for understanding the ultra-fast coupled non-local dynamics of electromagnetic fields and dissipation in superconductor films.

  4. PREFACE: Special section featuring selected papers from the 3rd International Workshop on Numerical Modelling of High Temperature Superconductors Special section featuring selected papers from the 3rd International Workshop on Numerical Modelling of High Temperature Superconductors

    Science.gov (United States)

    Granados, Xavier; Sánchez, Àlvar; López-López, Josep

    2012-10-01

    The development of superconducting applications and superconducting engineering requires the support of consistent tools which can provide models for obtaining a good understanding of the behaviour of the systems and predict novel features. These models aim to compute the behaviour of the superconducting systems, design superconducting devices and systems, and understand and test the behavior of the superconducting parts. 50 years ago, in 1962, Charles Bean provided the superconducting community with a model efficient enough to allow the computation of the response of a superconductor to external magnetic fields and currents flowing through in an understandable way: the so called critical-state model. Since then, in addition to the pioneering critical-state approach, other tools have been devised for designing operative superconducting systems, allowing integration of the superconducting design in nearly standard electromagnetic computer-aided design systems by modelling the superconducting parts with consideration of time-dependent processes. In April 2012, Barcelona hosted the 3rd International Workshop on Numerical Modelling of High Temperature Superconductors (HTS), the third in a series of workshops started in Lausanne in 2010 and followed by Cambridge in 2011. The workshop reflected the state-of-the-art and the new initiatives of HTS modelling, considering mathematical, physical and technological aspects within a wide and interdisciplinary scope. Superconductor Science and Technology is now publishing a selection of papers from the workshop which have been selected for their high quality. The selection comprises seven papers covering mathematical, physical and technological topics which contribute to an improvement in the development of procedures, understanding of phenomena and development of applications. We hope that they provide a perspective on the relevance and growth that the modelling of HTS superconductors has achieved in the past 25 years.

  5. EDITORIAL: Focus on Superconductors with Exotic Symmetries FOCUS ON SUPERCONDUCTORS WITH EXOTIC SYMMETRIES

    Science.gov (United States)

    Rice, T. Maurice; Sigrist, Manfred; Maeno, Yoshiteru

    2009-05-01

    Superconductors can usefully be divided into two classes, those that are well described by the classic Bardeen-Cooper-Schrieffer (BCS) theory and its extensions and those which require a different microscopic description. The BCS theory of superconductivity solved the long standing mystery of this spectacular phenomenon and described all superconductors that were known when it was formulated in the 1950s. The key ingredient is an attractive interaction generated by the exchange of phonons between electrons which overcomes a Coulomb repulsion weakened by screening, to give a net attractive force on the low energy scale. In this case the simplest s-wave pairing always maximises the energy gain. There were speculations a little later that other types of electron pairing could be possible, but it took a quarter of a century until the first signs of superconductors with different and exotic pairing appeared. In the intervening thirty years many superconductors with exotic pairing have been and continue to be discovered and the study of their superconductivity has grown into a major subfield of condensed matter physics today. The importance of these exotic superconductors with unconventional symmetry is that their pairing is of electronic origin. As a result they are freed from the restrictions of low transition temperatures that go along with the phonon driven conventional superconductors. However in two of the main classes of the exotic superconductors, namely heavy fermion and organic superconductors, the intrinsic energy scales are very small leading to low temperature scales. The third class contains the small number of superconducting transition metal compounds with exotic pairing symmetry. The most studied of these are the high-Tc cuprates, the newly discovered iron pnictides and strontium ruthenate which is closely related to superfluid 3He. Although the basic electronic structure of these materials is well understood, the origin of the pairing is more complex

  6. High-Throughput Screening by Nuclear Magnetic Resonance (HTS by NMR) for the Identification of PPIs Antagonists.

    Science.gov (United States)

    Wu, Bainan; Barile, Elisa; De, Surya K; Wei, Jun; Purves, Angela; Pellecchia, Maurizio

    2015-01-01

    In recent years the ever so complex field of drug discovery has embraced novel design strategies based on biophysical fragment screening (fragment-based drug design; FBDD) using nuclear magnetic resonance spectroscopy (NMR) and/or structure-guided approaches, most often using X-ray crystallography and computer modeling. Experience from recent years unveiled that these methods are more effective and less prone to artifacts compared to biochemical high-throughput screening (HTS) of large collection of compounds in designing protein inhibitors. Hence these strategies are increasingly becoming the most utilized in the modern pharmaceutical industry. Nonetheless, there is still an impending need to develop innovative and effective strategies to tackle other more challenging targets such as those involving protein-protein interactions (PPIs). While HTS strategies notoriously fail to identify viable hits against such targets, few successful examples of PPIs antagonists derived by FBDD strategies exist. Recently, we reported on a new strategy that combines some of the basic principles of fragment-based screening with combinatorial chemistry and NMR-based screening. The approach, termed HTS by NMR, combines the advantages of combinatorial chemistry and NMR-based screening to rapidly and unambiguously identify bona fide inhibitors of PPIs. This review will reiterate the critical aspects of the approach with examples of possible applications.

  7. Electromagnetic Performance Calculation of HTS Linear Induction Motor for Rail Systems

    Science.gov (United States)

    Liu, Bin; Fang, Jin; Cao, Junci; Chen, Jie; Shu, Hang; Sheng, Long

    2017-07-01

    According to a high temperature superconducting (HTS) linear induction motor (LIM) designed for rail systems, the influence of electromagnetic parameters and mechanical structure parameters on the electromagnetic horizontal thrust, vertical force of HTS LIM and the maximum vertical magnetic field of HTS windings are analyzed. Through the research on the vertical field of HTS windings, the development regularity of the HTS LIM maximum input current with different stator frequency and different thickness value of the secondary conductive plate is obtained. The theoretical results are of great significance to analyze the stability of HTS LIM. Finally, based on theory analysis, HTS LIM test platform was built and the experiment was carried out with load. The experimental results show that the theoretical analysis is correct and reasonable.

  8. Bi-based superconductor

    Directory of Open Access Journals (Sweden)

    S E Mousavi

    2009-08-01

    Full Text Available   In this paper, Bi-Sr-Ca-Cu-O (BCSCCO system superconductor is made by the solid state reaction method. The effect of doping Pb, Cd, Sb, Cu and annealing time on the critical temperature and critical current density have been investigated. The microstructure and morphology of the samples have been studied by X-ray diffraction, scanning electron microscope and energy dispersive X-ray. The results show that the fraction of Bi-2223 phase in the Bi- based superconductor, critical temperature and critical current density depend on the annealing temperature, annealing time and the kind and amount of doping .

  9. Physical Vacuum in Superconductors

    CERN Document Server

    de Matos, Clovis Jacinto

    2009-01-01

    Although experiments carried out by Jain et al. showed that the Cooper pairs obey the strong equivalence principle, The measurement of the Cooper pairs inertial mass by Tate et al. revealed an anomalous excess of mass. In the present paper we interpret these experimental results in the framework of an electromagnetic model of dark energy for the superconductors' vacuum. We argue that this physical vacuum is associated with a preferred frame. Ultimately from the conservation of energy for Cooper pairs we derive a model for a variable vacuum speed of light in the superconductors physical vacuum in relation with a possible breaking of the weak equivalence principle for Cooper pairs.

  10. Feasibility of introducing ferromagnetic materials to onboard bulk high-T{sub c} superconductors to enhance the performance of present maglev systems

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Zigang, E-mail: zgdeng@gmail.com [Applied Superconductivity Laboratory (ASCLab), Southwest Jiaotong University (SWJTU), Chengdu, Sichuan 610031 (China); State Key Laboratory of Traction Power (TPL), Southwest Jiaotong University (SWJTU), Chengdu, Sichuan 610031 (China); Wang, Jiasu [Applied Superconductivity Laboratory (ASCLab), Southwest Jiaotong University (SWJTU), Chengdu, Sichuan 610031 (China); Zheng, Jun; Zhang, Ya [Applied Superconductivity Laboratory (ASCLab), Southwest Jiaotong University (SWJTU), Chengdu, Sichuan 610031 (China); State Key Laboratory of Traction Power (TPL), Southwest Jiaotong University (SWJTU), Chengdu, Sichuan 610031 (China); Wang, Suyu [Applied Superconductivity Laboratory (ASCLab), Southwest Jiaotong University (SWJTU), Chengdu, Sichuan 610031 (China)

    2013-02-14

    Highlights: ► Ferromagnetic materials guide the flux distribution of the PMG to bulk positions. ► With ferromagnetic materials, guidance performance can be enhanced greatly. ► A new HTS Maglev system with onboard ferromagnetic materials is designed. ► The design can meet large guidance force requirements for practical applications. -- Abstract: Performance improvement is a long-term research task for the promotion of practical application of promising high-temperature superconducting (HTS) magnetic levitation (maglev) vehicle technologies. We studied the feasibility to enhance the performance of present HTS Maglev systems by introducing ferromagnetic materials to onboard bulk superconductors. The principle here is to make use of the high magnetic permeability of ferromagnetic materials to alter the flux distribution of the permanent magnet guideway for the enhancement of magnetic field density at the position of the bulk superconductors. Ferromagnetic iron plates were added to the upper surface of bulk superconductors and their geometric and positioning effects on the maglev performance were investigated experimentally. Results show that the guidance performance (stability) was enhanced greatly for a particular setup when compared to the present maglev system which is helpful in the application where large guidance forces are needed such as maglev tracks with high degrees of curves.

  11. The 2013 Workshop on Electromagnetic and Mechanical Effects in Superconductors (MEM13) The 2013 Workshop on Electromagnetic and Mechanical Effects in Superconductors (MEM13)

    Science.gov (United States)

    Mitchell, Neil

    2013-11-01

    The 2013 MEM workshop is the sixth in the series and proved to be one of the largest, with over 60 participants and over 40 presentations. Only a small selection of these presentations have progressed from PowerPoint to a reviewed paper accepted for publication in Superconductor Science and Technology (SUST). However, the dynamics of a good workshop should not be judged solely by the output of high quality papers. The interplay between electromagnetic and mechanical effects in superconductors is proving to be one of the critical issues in understanding the factors that dominate the practical application of not only the more traditional low temperature superconductors (LTS) but also, perhaps surprisingly, the high temperature superconductors (HTS) materials too. The lessons learned in the design and the diagnostic techniques which have been developed for LTS now overlap into the HTS field. The MEM13 workshop provided an opportunity for informal discussion across these fields, to the benefit of all. The topics of the workshop were selected to allow, as far as practically possible, co-presentation of LTS and HTS materials, as follows: Electro-mechanical effects on practical conductor performance. Analysis of electro-mechanical effects. Diagnosis of electro-mechanical effects. Strain dependence. Simulations and standardized tests for electro-mechanical effects. Microstructure, properties and sensitivity. Coated conductors. Manufacture of LTS and HTS conductors. The papers were wide ranging, covering basic manufacturing issues through to sophisticated testing and advanced diagnosis tools. The MEM13 workshop provided many papers based on the ITER construction, and diagnoses using the large quantity of data available from the industrial scale fabrication and testing of ITER conductors, as well as papers on the frontiers of HTS industrial technologies. It was clear that the huge industrial fabrication of Nb3Sn conductors for ITER, and the associated test programmes, have

  12. Iron-Based Superconductors as topological matter

    Science.gov (United States)

    Hu, Jiangping

    We show the existence of non-trivial topological properties in Iron-based superconductors. Several examples are provided, including (1) the single layer FeSe grown on SrTiO3 substrate, in which an topological insulator phase exists due to the band inversion at M point; (2) CaFeAs2, a staggered intercalation compound that integrates both quantum spin hall and superconductivity in which the nontrivial topology stems from the chain-like As layers away from FeAs layers; (3) the Fe(Te,Se) thin films in which the nontrivial Z2 topological invariance originates from the parity exchange at Γ point that is controlled by the Te(Se) height; (4 nontrivial topology that is driven by the nematic order in FeSe. These results lay ground for integrating high Tc superconductivity with topological properties to realize new emergent phenomena, such as majorana particles, in iron-based high temperature superconductors

  13. Topological properties in Iron-Based Superconductors

    Science.gov (United States)

    Hu, Jiangping; Hao, Ningning; Wu, X. X.

    2015-03-01

    We show the existence of non-trivial topological properties in Iron-based superconductors. Several examples are provided, including (1) the single layer FeSe grown on SrTiO3 substrate, in which an topological insulator phase exists due to the band inversion at M point; (2) CaFeAs2, a staggered intercalation compound that integrates both quantum spin hall and superconductivity in which the nontrivial topology stems from the chain-like As layers away from FeAs layers; (3) the Fe(Te,Se) thin films in which the nontrivial Z2 topological invariance originates from the parity exchange at ? point that is controlled by the Te(Se) height. These results lay ground for integrating high Tc superconductivity with topological properties to realize new emergent phenomena, such as majorana particles, in iron-based high temperature superconductors. The work is supported by NSFC and the Ministry of Science and Technology of China.

  14. Searching for the Genes of Unconventional High Temperature Superconductors

    Science.gov (United States)

    Hu, Jiangping

    In the past, both curates and iron-based superconductors were discovered accidentally. Lacking of successful predictions on new high Tc materials is one of major obstacles to reach a consensus on the high Tc mechanism. In this talk, we discuss two emergent principles, which are called as the correspondence principle and the selective magnetic pairing rule, to unify the understanding of both cuprates and iron-based superconductors. These two principles provide an unified explanation why the d-wave pairing symmetry and the s-wave pairing symmetry are robust respectively in cuprates and iron-based superconductors. In the meanwhile, the above two principles explain the rareness of unconventional high Tc superconductivity, identify necessary electronic environments required for high Tc superconductivity and finally serve as direct guiding rules to search new high Tc materials. We predict that the third family of unconventional high Tc superconductors exist in the compounds which carry two dimensional hexagonal lattices formed by cation-anion trigonal bipyramidal complexes with a d filling configuration on the cation ions. Their superconducting states are expected to be dominated by the d+id pairing symmetry and their maximum Tc should be higher than those of iron-based superconductors. Verifying the prediction can convincingly establish the high Tc superconducting mechanism and pave a way to design new high Tc superconductors

  15. Development of toroid-type HTS DC reactor series for HVDC system

    Science.gov (United States)

    Kim, Kwangmin; Go, Byeong-Soo; Park, Hea-chul; Kim, Sung-kyu; Kim, Seokho; Lee, Sangjin; Oh, Yunsang; Park, Minwon; Yu, In-Keun

    2015-11-01

    This paper describes design specifications and performance of a toroid-type high-temperature superconducting (HTS) DC reactor. The first phase operation targets of the HTS DC reactor were 400 mH and 400 A. The authors have developed a real HTS DC reactor system during the last three years. The HTS DC reactor was designed using 2G GdBCO HTS wires. The HTS coils of the toroid-type DC reactor magnet were made in the form of a D-shape. The electromagnetic performance of the toroid-type HTS DC reactor magnet was analyzed using the finite element method program. A conduction cooling method was adopted for reactor magnet cooling. The total system has been successfully developed and tested in connection with LCC type HVDC system. Now, the authors are studying a 400 mH, kA class toroid-type HTS DC reactor for the next phase research. The 1500 A class DC reactor system was designed using layered 13 mm GdBCO 2G HTS wire. The expected operating temperature is under 30 K. These fundamental data obtained through both works will usefully be applied to design a real toroid-type HTS DC reactor for grid application.

  16. A perspective on 10-years HTS experience at the Walter and Eliza Hall Institute of Medical Research - eighteen million assays and counting.

    Science.gov (United States)

    Lackovic, Kurt; Lessene, Guillaume; Falk, Hendrik; Leuchowius, Karl-Johan; Baell, Jonathan; Street, Ian

    2014-03-01

    The Walter and Eliza Hall Institute of Medical Research (WEHI) is Australia's longest serving medical research institute. WEHI's High Throughput Screening (HTS) Facility was established in 2003 with $5 million of infrastructure funds invested by WEHI, and the Victorian State Government's Strategic Technology Initiative through Bio21 Australia Ltd. The Facility was Australia's first truly academic HTS facility and was one of only a handful operating in publicly funded institutions worldwide at that time. The objectives were to provide access to enabling HTS technologies, such as assay design, liquid handling automation, compound libraries and expertise to promote translation of basic research in a national setting that has a relatively young biotech sector and does not have a big Pharma research presence. Ten years on and the WEHI HTS Facility has participated in over 92 collaborative projects, generated over 18 million data points, and most importantly, projects that began in the Facility have been commercialized successfully (due to strong ties with Business Development and emphasis on intellectual property management) and now have molecules progressing in clinical trials.

  17. HTS step-edge Josephson junction terahertz harmonic mixer

    Science.gov (United States)

    Du, Jia; Weily, Andrew R.; Gao, Xiang; Zhang, Ting; Foley, Cathy P.; Guo, Yingjie Jay

    2017-02-01

    A high-temperature superconducting (HTS) terahertz (THz) frequency down-converter or mixer based on a thin-film ring-slot antenna coupled YBa2Cu3O7-x (YBCO)/MgO step-edge Josephson junction is reported. The frequency down-conversion was achieved using higher order harmonics of an applied lower frequency (19-40 GHz) local oscillator signal in the Josephson junction mixing with a THz signal of over 600 GHz, producing a 1-3 GHz intermediate frequency signal. Up to 31st order of harmonic mixing was obtained and the mixer operated stably at temperatures up to 77 K. The design details of the antenna, HTS Josephson junction mixer, the matching and isolation circuits, and the DC and RF performance evaluation are described in this paper.

  18. Influence of lateral displacement on the levitation performance of a magnetized bulk high-T{sub c} superconductor magnet

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W., E-mail: tonny-violet@163.com [College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu 610059 (China) and Applied Superconductivity Laboratory, Southwest Jiaotong University, Chengdu 610031 (China); Wang, J.S.; Ma, G.T.; Zheng, J. [Applied Superconductivity Laboratory, Southwest Jiaotong University, Chengdu 610031 (China); State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031 (China); National Laboratory of Rail Transit, Chengdu, 610031 (China); Tuo, X.G.; Li, L.L. [College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu 610059 (China); Ye, C.Q.; Liao, X.L. [Applied Superconductivity Laboratory, Southwest Jiaotong University, Chengdu 610031 (China); National Laboratory of Rail Transit, Chengdu, 610031 (China); Wang, S.Y. [Applied Superconductivity Laboratory, Southwest Jiaotong University, Chengdu 610031 (China); State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031 (China); National Laboratory of Rail Transit, Chengdu, 610031 (China)

    2012-03-15

    Compared with the permanent magnet, the magnetized bulk high-T{sub c} superconductor magnet (MBSCM) can trap higher magnetic field due to its strong flux pinning ability, so it is a good candidate to improve the levitation performance of high-T{sub c} superconductive (HTS) maglev system. The trapped magnetic flux of a MBSCM is sustained by the inductive superconducting current produced by the magnetizing process and is susceptible to the current intensity as well as configuration. In the HTS maglev system, the lateral displacement is an important process to change the superconducting current within a MBSCM and then affects its levitation performance, which is essential for the traffic ability in curve-way, the loading capacity of lateral impact and so on. The research about influence of lateral displacement on the levitation performance of MBSCM is necessary when MBSCM is applied on the HTS maglev vehicle. The experimental investigations about the influence of lateral displacement on the levitation performance of a MBSCM with different trapped fluxes and applied fields are processed in this article. The analyses and conclusions of this article are useful for the practical application of MBSCM in HTS maglev system.

  19. Electronic evidence of an insulator-superconductor crossover in single-layer FeSe/SrTiO3 films.

    Science.gov (United States)

    He, Junfeng; Liu, Xu; Zhang, Wenhao; Zhao, Lin; Liu, Defa; He, Shaolong; Mou, Daixiang; Li, Fangsen; Tang, Chenjia; Li, Zhi; Wang, Lili; Peng, Yingying; Liu, Yan; Chen, Chaoyu; Yu, Li; Liu, Guodong; Dong, Xiaoli; Zhang, Jun; Chen, Chuangtian; Xu, Zuyan; Chen, Xi; Ma, Xucun; Xue, Qikun; Zhou, X J

    2014-12-30

    In high-temperature cuprate superconductors, it is now generally agreed that superconductivity is realized by doping an antiferromagnetic Mott (charge transfer) insulator. The doping-induced insulator-to-superconductor transition has been widely observed in cuprates, which provides important information for understanding the superconductivity mechanism. In the iron-based superconductors, however, the parent compound is mostly antiferromagnetic bad metal, raising a debate on whether an appropriate starting point should go with an itinerant picture or a localized picture. No evidence of doping-induced insulator-superconductor transition (or crossover) has been reported in the iron-based compounds so far. Here, we report an electronic evidence of an insulator-superconductor crossover observed in the single-layer FeSe film grown on a SrTiO3 substrate. By taking angle-resolved photoemission measurements on the electronic structure and energy gap, we have identified a clear evolution of an insulator to a superconductor with increasing carrier concentration. In particular, the insulator-superconductor crossover in FeSe/SrTiO3 film exhibits similar behaviors to that observed in the cuprate superconductors. Our results suggest that the observed insulator-superconductor crossover may be associated with the two-dimensionality that enhances electron localization or correlation. The reduced dimensionality and the interfacial effect provide a new pathway in searching for new phenomena and novel superconductors with a high transition temperature.

  20. Disappearance of nodal gap across the insulator-superconductor transition in a copper-oxide superconductor.

    Science.gov (United States)

    Peng, Yingying; Meng, Jianqiao; Mou, Daixiang; He, Junfeng; Zhao, Lin; Wu, Yue; Liu, Guodong; Dong, Xiaoli; He, Shaolong; Zhang, Jun; Wang, Xiaoyang; Peng, Qinjun; Wang, Zhimin; Zhang, Shenjin; Yang, Feng; Chen, Chuangtian; Xu, Zuyan; Lee, T K; Zhou, X J

    2013-01-01

    The parent compound of the copper-oxide high-temperature superconductors is a Mott insulator. Superconductivity is realized by doping an appropriate amount of charge carriers. How a Mott insulator transforms into a superconductor is crucial in understanding the unusual physical properties of high-temperature superconductors and the superconductivity mechanism. Here we report high-resolution angle-resolved photoemission measurement on heavily underdoped Bi₂Sr₂-xLaxCuO(₆+δ) system. The electronic structure of the lightly doped samples exhibit a number of characteristics: existence of an energy gap along the nodal direction, d-wave-like anisotropic energy gap along the underlying Fermi surface, and coexistence of a coherence peak and a broad hump in the photoemission spectra. Our results reveal a clear insulator-superconductor transition at a critical doping level of ~0.10 where the nodal energy gap approaches zero, the three-dimensional antiferromagnetic order disappears, and superconductivity starts to emerge. These observations clearly signal a close connection between the nodal gap, antiferromagnetism and superconductivity.

  1. Electrical Model of Balanced AC HTS Power Cable

    Science.gov (United States)

    Zuijderduin, R.; Chevtchenko, O.; Smit, J. J.; Willén, D.; Melnik, I.; Geschiere, A.

    The future electricity grid will be more sustainable and it will have more power transmission and distribution capability with more electrical power added from decentralized sources on distribution level and from wind parks and other large sources on transmission level. More interconnections and more underground transmission and distribution will be put up. Use of high temperature superconducting (HTS) power cables provides solutions to many of the future grid problems caused by these trends. In this paper we present an electrical model of a balanced 6 km-long three phase triaxial HTS power cable for the Dutch project being developed by a consortium of Alliander, Ultera™ and TUD. The cable currents in all three phases are balanced by selecting proper twist pitches and insulation thickness. The paper focuses on determining inductances, capacitances and AC losses of the balanced cable. Using the developed model, we also determine the voltage drop as function of the cable length, the neutral current and the effect of the imbalanced capacitances on the current distribution of the Dutch distribution cable. The model is validated and it can be used for accurate simulation of the electrical behaviour of triaxial HTS cables in electrical grids.

  2. Testing of an HTS Power Cable Made from YBCO Tapes

    Energy Technology Data Exchange (ETDEWEB)

    Gouge, Michael J [ORNL; Duckworth, Robert C [ORNL; Demko, Jonathan A [ORNL; Rey, Christopher M [ORNL; Lindsay, David T [ORNL; Roden, Mark L [ORNL; Tolbert, Jerry Carlton [ORNL

    2007-01-01

    Oak Ridge National Laboratory (ORNL) has designed, built, and tested a 1.25-m-long, prototype high temperature superconducting (HTS) power cable made from second-generation YBa2Cu3Ox (YBCO)-coated conductor tapes. Electrical tests of this cable were performed in liquid nitrogen at 77 K. DC testing of the HTS cable included determination of the V-I curve with a critical current of about 2100 A, which was consistent with the critical currents of the two layers of 4.4-mm wide YBCO tapes. AC testing of the cable was conducted at currents up to about 1500 Arms. The ac losses were determined calorimetrically by measuring the response of a calibrated temperature sensor placed on the former and electrically by use of a Rogowski coil with a lock-in amplifier. Over-current testing was conducted at peak current values up to 4.9 kA for pulse lengths of 0.3-0.5 s. Test results are compared to earlier data from a 1.25-m-long power cable made from 1-cm-wide YBCO tapes and also comparable BSCCO cables. This commercial-grade HTS cable demonstrated the feasibility of second-generation YBCO tapes in an ac cable application.

  3. Optimal Design of HTS Linear Induction Motors%高温超导直线感应电机的优化设计

    Institute of Scientific and Technical Information of China (English)

    赵佳; 郑琼林; 张威; 方进; 刘友梅

    2011-01-01

    The structure design and primary winding arrangment of a high temperature superconductor linear induction motor(HTS LIM) are discussed in detail.The relationship curve between the critical current and background field of the HTS tape is given.Using the finite element analysis software Maxwell the electromagnetic properties of the HTS LIM are analyzed.And the key parameters such as the primary coil number,primary slot height and primary slot width are sweeped and optimized.The influence of these key parameters on the thrust force,primary slot leakage flux and critical current of the HTS LIM is also analyzed.Based on the analysis the optimal design method is proposed.According to the structure and the parameters of the HTS LIM a prototype linear induction motor with copper primary windings is manufactured.The thrust force of the prototype motor is tested with different currents and speeds.Comparing the test results with the simulation results a modified coefficient of the thrust is obtained.This coefficient is meaningful for studying the thrust force with different motor parameters.%详细讨论了高温超导直线感应电机的结构设计和初级绕组排列方式,给出了高温超导带材临界电流和背景磁场的关系曲线。采用Maxwell有限元电磁分析软件对高温超导直线感应电机进行了详细的电磁分析,并对初级绕组匝数、初级铁心槽高和初级铁心槽宽等关键参数进行了参数扫描和优化,分析了它们对电机电磁力、初级槽漏磁通和电机临界电流的影响,提出了高温超导直线感应电机的优化设计方法。根据得到的高温超导直线感应电机优化设计参数制造了一台完全相同的铜绕组实验样机,测试了样机在不同电流和速度下的推力,对比相同条件下得到的有限元电磁仿

  4. Multi-scale model of resistive-type superconducting fault current limiters based on 2G HTS coated conductors

    Science.gov (United States)

    Bonnard, Charles-Henri; Sirois, Frédéric; Lacroix, Christian; Didier, Gaëtan

    2017-01-01

    In order to plan the integration of superconducting fault current limiters (SFCLs) in power systems, accurate models of SFCLs must be made available in commercial power system transient simulators. In this context, we developed such a model for the EMTP-RV software package, a power system transient simulator widely used by power utilities. The model can be used with any resistive-type SFCL (rSFCL) made of high temperature superconductor (HTS) tapes, which are discretized in ‘electro-thermal elements’. Those elements consist solely of electric circuit components, and are used to represent portions of tape of various sizes and dimensions (a ‘multi-scale’ approach). Both the electrical and thermal behaviors of the tape are modeled, including interfacial effects, nonlinear properties of materials and heat transfer to the surrounding environment. Such a multi-scale model can simulate accurately both the local quench dynamics of HTS tapes (microscopic scale) and the global impact of the rSFCL on the power system (macroscopic/system scale). In this paper, the model is used to compute phenomena such as propagation velocity of a hot spot and heat diffusion through the thickness of the tape. Results were verified by comparing EMTP-RV results with finite element simulations. In addition to the development of the multi-scale model itself, which is the major contribution of this paper, the use of the model allowed us to determine the conditions of validity of the commonly used ‘homogenization’ of the thermal properties across the tape thickness. Indeed, when the current flowing into the rSFCL is slightly above its critical current I c (and up to 2{I}{{c}}), very important errors in the power waveforms arise, leading to potentially wrong decisions of protection systems. Homogenized thermal models should thus be used with great care in practice.

  5. Ambient-pressure organic superconductor

    Science.gov (United States)

    Williams, Jack M.; Wang, Hsien-Hau; Beno, Mark A.

    1986-01-01

    A new class of organic superconductors having the formula (ET).sub.2 MX.sub.2 wherein ET represents bis(ethylenedithio)-tetrathiafulvalene, M is a metal such as Au, Ag, In, Tl, Rb, Pd and the like and X is a halide. The superconductor (ET).sub.2 AuI.sub.2 exhibits a transition temperature of 5 K which is high for organic superconductors.

  6. Dissipative flux motion in high-temperature superconductors

    NARCIS (Netherlands)

    Palstra, T.T.M.; Batlogg, B.; Dover, R.B. van; Schneemeyer, L.F.; Waszczak, J.V.

    1990-01-01

    The dissipation below Tc has been studied for representatives of all classes of cuprate hightemperature superconductors, including Ba2YCu3O7–δ, and Bi and Tl compounds. The results are parametrized in the framework of flux creep, with the largest activation energies found in Ba2YCu3O7. It is argued

  7. Vertical and lateral forces between a permanent magnet and a high-temperature superconductor

    Science.gov (United States)

    Hull, John R.; Cansiz, Ahmet

    1999-12-01

    The vertical and horizontal forces and associated stiffnesses on a permanent magnet (PM) above a high-temperature superconductor (HTS) were measured during vertical and horizontal traverses in zero-field cooling (ZFC) and in field cooling (FC). In ZFC, the vertical stiffness was greater in the first descent than in the first ascent and second descent, and the stiffness in the second descent was between those of the first descent and the first ascent. At the FC position, the vertical stiffness was two times greater than the lateral stiffness at each height, to within 1% of the vertical stiffness value. The cross stiffness of vertical force with respect to lateral position was positive for FC, but negative for ZFC. Free-spin-down experiments of a PM levitated above a HTS were also performed. These results showed that the coefficient of friction is double valued at frequencies just below the rotor resonance, a result attributed to cross stiffness in the PM/HTS interaction. A frozen-image model was used to calculate the vertical and horizontal forces and stiffnesses, and reasonable agreement with the data occurred for vertical or horizontal movements of the PM less than several mm from the FC position.

  8. Coasting characteristic of the flywheel system under anisotropy effect of bulk high temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J.F., E-mail: wujf@ciomp.ac.cn; Li, Y.

    2014-10-15

    Highlights: • Coasting time was investigated from the point-view of HTS flywheel applications. • The coasting time of aligned growth section boundary pattern (AGSBP) is shorter than that of MGSBP. • The electric magnetic drag force with AGSBP is larger than that of MGSBP. • This result may also exist in the maglev guideline when the maglev train stops freely. - Abstract: High-temperature superconductors (HTSCs) array with aligned growth section boundary (GSB) pattern (AGSBP) exhibits larger levitation force and suppression of levitation force decay above a permanent magnet guideway (PMG) compared with misaligned GSB pattern (MGSBP) has been studied in maglev train application (Zheng et al., 2013). This result maybe helpful and support a new way for the HTS bearing design for flywheel systems. So, in this paper, we further examine this growth anisotropy effect on the maglev performance of flywheel system. Levitation force and coasting time were investigated from the point-view of HTS flywheel applications. The GS/GSB alignment of AGSBP bulk HTSCs produces larger levitation force than that of MGSBP, but the coasting time is shorter than that of MGSBP, that is to say, the electric magnetic drag force with AGSBP is larger than that of MGSBP. This result may also exist in the maglev guideline when the maglev train stops freely.

  9. Theoretical study of pair density wave superconductors

    Science.gov (United States)

    Zheng, Zhichao

    In conventional superconductors, the Cooper pairs are formed from quasiparticles. We explore another type of superconducting state, a pair density wave (PDW) order, which spontaneously breaks some of the translational and point group symmetries. In a PDW superconductor, the order parameter is a periodic function of the center-of-mass coordinate, and the spatial average value of the superconducting order parameter vanishes. In the early 1960s, following the success of the BCS theory of superconductivity, Fulde and Ferrell and Larkin and Ovchinnikov (FFLO) developed theories of inhomogeneous superconducting states. Because of this Zeeman splitting in a magnetic field, the Cooper pairs having a nonzero center-of-mass momentum are more stable than the normal pairing, leading to the FFLO state. Experiments suggest possible occurrence of the FFLO state in the heavy-fermion compound CeCoIn5, and in quasi-low-dimensional organic superconductors. FFLO phases have also been argued to be of importance in understanding ultracold atomic Fermi gases and in the formation of color superconductivity in high density quark matter. In all Fermi superfluids known at the present time, Cooper pairs are composed of particles with spin 1/2. The spin component of a pair wave function can be characterized by its total spin S = 0 (singlet) and S = 1 (triplet). In the discovered broken inversion superconductors CePt3Si, Li2Pt3B, and Li2Pd3B, the magnetic field leads to novel inhomogeneous superconducting states, namely the helical phase and the multiple-q phase. Its order parameter exhibits periodicity similar to FFLO phase, and the consequences of both phases are same: the enhancement of transition temperature as a function of magnetic field. We have studied the PDW phases in broken parity superconductors with vortices included. By studying PDW vortex states, we find the usual Abrikosov vortex solution is unstable against a new solution with fractional vortex pairs. We have also studied the

  10. Introduction to Holographic Superconductor Models

    CERN Document Server

    Cai, Rong-Gen; Li, Li-Fang; Yang, Run-Qiu

    2015-01-01

    In the last years it has been shown that some properties of strongly coupled superconductors can be potentially described by classical general relativity living in one higher dimension, which is known as holographic superconductors. This paper gives a quick and introductory overview of some holographic superconductor models with s-wave, p-wave and d-wave orders in the literature from point of view of bottom-up, and summarizes some basic properties of these holographic models in various regimes. The competition and coexistence of these superconductivity orders are also studied in these superconductor models.

  11. Vortices and nanostructured superconductors

    CERN Document Server

    2017-01-01

    This book provides expert coverage of modern and novel aspects of the study of vortex matter, dynamics, and pinning in nanostructured and multi-component superconductors. Vortex matter in superconducting materials is a field of enormous beauty and intellectual challenge, which began with the theoretical prediction of vortices by A. Abrikosov (Nobel Laureate). Vortices, vortex dynamics, and pinning are key features in many of today’s human endeavors: from the huge superconducting accelerating magnets and detectors at the Large Hadron Collider at CERN, which opened new windows of knowledge on the universe, to the tiny superconducting transceivers using Rapid Single Flux Quanta, which have opened a revolutionary means of communication. In recent years, two new features have added to the intrinsic beauty and complexity of the subject: nanostructured/nanoengineered superconductors, and the discovery of a range of new materials showing multi-component (multi-gap) superconductivity. In this book, leading researche...

  12. Vortex cutting in superconductors

    Science.gov (United States)

    Glatz, A.; Vlasko-Vlasov, V. K.; Kwok, W. K.; Crabtree, G. W.

    2016-08-01

    Vortex cutting and reconnection is an intriguing and still-unsolved problem central to many areas of classical and quantum physics, including hydrodynamics, astrophysics, and superconductivity. Here, we describe a comprehensive investigation of the crossing of magnetic vortices in superconductors using time dependent Ginsburg-Landau modeling. Within a macroscopic volume, we simulate initial magnetization of an anisotropic high temperature superconductor followed by subsequent remagnetization with perpendicular magnetic fields, creating the crossing of the initial and newly generated vortices. The time resolved evolution of vortex lines as they approach each other, contort, locally conjoin, and detach, elucidates the fine details of the vortex-crossing scenario under practical situations with many interacting vortices in the presence of weak pinning. Our simulations also reveal left-handed helical vortex instabilities that accompany the remagnetization process and participate in the vortex crossing events.

  13. Synchronous Generator with HTS-2G field coils for Windmills with output power 1 MW

    Science.gov (United States)

    Kovalev, K.; Kovalev, L.; Poltavets, V.; Samsonovich, S.; Ilyasov, R.; Levin, A.; Surin, M.

    2014-05-01

    Nowadays synchronous generators for wind-mills are developed worldwide. The cost of the generator is determined by its size and weight. In this deal the implementation of HTS-2G generators is very perspective. The application of HTS 2G field coils in the rotor allows to reduce the size of the generator is 1.75 times. In this work the design 1 MW HTS-2G generator is considered. The designed 1 MW HTS-2G generator has the following parameters: rotor diameter 800 mm, active length 400 mm, phase voltage 690V, rotor speed 600 min-1 rotor field coils with HTS-2G tapes. HTS-2G field coils located in the rotating cryostat and cooled by liquid nitrogen. The simulation and optimization of HTS-2G field coils geometry allowed to increase feed DC current up to 50A. Copper stator windings are water cooled. Magnetic and electrical losses in 1 MW HTS-2G generator do not exceed 1.6% of the nominal output power. In the construction of HTS-2G generator the wave multiplier with ratio 1:40 is used. The latter allows to reduce the total mass of HTS-2G generator down to 1.5 tons. The small-scale model of HTS-2G generator with output power 50 kW was designed, manufactured and tested. The test results showed good agreement with calculation results. The manufacturing of 1 MW HTS-2G generator is planned in 2014. This work is done under support of Rosatom within the frames of Russian Project "Superconducting Industry".

  14. Study on AC loss measurements of HTS power cable for standardizing

    Science.gov (United States)

    Mukoyama, Shinichi; Amemiya, Naoyuki; Watanabe, Kazuo; Iijima, Yasuhiro; Mido, Nobuhiro; Masuda, Takao; Morimura, Toshiya; Oya, Masayoshi; Nakano, Tetsutaro; Yamamoto, Kiyoshi

    2017-09-01

    High-temperature superconducting power cables (HTS cables) have been developed for more than 20 years. In addition of the cable developments, the test methods of the HTS cables have been discussed and proposed in many laboratories and companies. Recently the test methods of the HTS cables is required to standardize and to common in the world. CIGRE made the working group (B1-31) for the discussion of the test methods of the HTS cables as a power cable, and published the recommendation of the test method. Additionally, IEC TC20 submitted the New Work Item Proposal (NP) based on the recommendation of CIGRE this year, IEC TC20 and IEC TC90 started the standardization work on Testing of HTS AC cables. However, the individual test method that used to measure a performance of HTS cables hasn’t been established as world’s common methods. The AC loss is one of the most important properties to disseminate low loss and economical efficient HTS cables in the world. We regard to establish the method of the AC loss measurements in rational and in high accuracy. Japan is at a leading position in the AC loss study, because Japanese researchers have studied on the AC loss technically and scientifically, and also developed the effective technologies for the AC loss reduction. The JP domestic commission of TC90 made a working team to discussion the methods of the AC loss measurements for aiming an international standard finally. This paper reports about the AC loss measurement of two type of the HTS conductors, such as a HTS conductor without a HTS shield and a HTS conductor with a HTS shield. The AC loss measurement method is suggested by the electrical method..

  15. The polar Kerr effect in superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Robbins, Joshua; Annett, James F.; Gradhand, Martin [University of Bristol (United Kingdom)

    2016-07-01

    The polar Kerr effect is an optical phenomenon which arises in states with broken time-reversal symmetry. This effect has recently been observed in a series of unconventional superconductors, including the layered perovskite compound Sr{sub 2}RuO{sub 4}. Confirmation of a Kerr signal below T{sub c} supports the hypothesis of chiral p-wave superconductivity in this material. However, the nature of the unconventional superconducting state remains a source of controversy. Here, we present calculations for the chiral superconducting state including spin-orbit coupling (SOC) by extending the three dimensional, multiband model considered previously. SOC was found to induce strong mixing of the orbital characters within the bandstructure. This mixing is essential for the existence of the polar Kerr effect and the large increase due to SOC has a significant influence on the frequency dependence of the predicted Kerr signal. We will extend and apply the model to other unconventional superconductors which have displayed the Kerr effect in recent years. This will allow a detailed study of the symmetry properties of these systems and will provide valuable insight into the pairing mechanism of superconductors.

  16. Superconducting Electronics Research at CSIRO Australia——20 Years after Discovery of HTS

    Institute of Scientific and Technical Information of China (English)

    Jia Du; Cathy P. Foley; Keith L. Leslie

    2008-01-01

    CSIRO has had a long-term research effort in superconductivity, in particular, since the discovery of HTS which promised big prospects. Significant progress has been made in research and development of HTS electronic devices and systems for practical applications such as mineral and exploration as well as some niche applications in emerging science and technology areas. This article presents an overview of the CSIRO research activities in HTS supercon- ducting electronics since 1987, outlining the HTS junction and device technology as well as various application systems developed by the group.

  17. Test results of a HTS power transformer connected to a power grid

    Science.gov (United States)

    Kimura, H.; Honda, K.; Hayashi, H.; Tsutsumi, K.; Iwakuma, M.; Funaki, K.; Bohno, T.; Tomioka, A.; Yagi, Y.; Maruyama, H.; Ohashi, K.

    2002-08-01

    A 22 kV/6.9 kV-1 MVA high- Tc superconducting (HTS) power transformer has been developed as a prototype with single-phase part of a 3 MVA HTS power transformer. The prototype unit is cooled by a continuous subcooled liquid nitrogen (LN 2) supply system with cryocoolers. During the field tests, the HTS transformer was connected to a distribution line at Imajuku substation (Kyushu Electric Power Co., Inc.) in Fukuoka, and inrush-current test and a long-term operation test were implemented. The test results demonstrated the HTS power transformer's applicability to a power grid.

  18. Processing of Superconductor-Normal-Superconductor Josephson Edge Junctions

    Science.gov (United States)

    Kleinsasser, A. W.; Barner, J. B.

    1997-01-01

    The electrical behavior of epitaxial superconductor-normal-superconductor (SNS) Josephson edge junctions is strongly affected by processing conditions. Ex-situ processes, utilizing photoresist and polyimide/photoresist mask layers, are employed for ion milling edges for junctions with Yttrium-Barium-Copper-Oxide (YBCO) electrodes and primarily Co-doped YBCO interlayers.

  19. Design, Test and Demonstration of Saturable Reactor High-Temperature Superconductor Fault Current Limiters

    Energy Technology Data Exchange (ETDEWEB)

    Darmann, Frank [Zenergy Power, Inc., Burlingame, CA (United States); Lombaerde, Robert [Zenergy Power, Inc., Burlingame, CA (United States); Moriconi, Franco [Zenergy Power, Inc., Burlingame, CA (United States); Nelson, Albert [Zenergy Power, Inc., Burlingame, CA (United States)

    2012-03-01

    Zenergy Power has successfully designed, built, tested, and installed in the US electrical grid a saturable reactor Fault Current Limiter. Beginning in 2007, first as SC Power Systems and from 2008 as Zenergy Power, Inc., ZP used DOE matching grant and ARRA funds to help refine the design of the saturated reactor fault current limiter. ZP ultimately perfected the design of the saturated reactor FCL to the point that ZP could reliably design a suitable FCL for most utility applications. Beginning with a very basic FCL design using 1G HTS for a coil housed in a LN2 cryostat for the DC bias magnet, the technology progressed to a commercial system that was offered for sale internationally. Substantial progress was made in two areas. First, the cryogenics cooling system progressed from a sub-cooled liquid nitrogen container housing the HTS coils to cryostats utilizing dry conduction cooling and reaching temperatures down to less than 20 degrees K. Large, round cryostats with warm bore diameters of 1.7 meters enabled the design of large tanks to hold the AC components. Second, the design of the AC part of the FCL was refined from a six legged spider design to a more compact and lighter design with better fault current limiting capability. Further refinement of the flux path and core shape led to an efficient saturated reactor design requiring less Ampere-turns to saturate the core. In conclusion, the development of the saturable reactor FCL led to a more efficient design not requiring HTS magnets and their associated peripheral equipment, which yielded a more economical product in line with the electric utility industry expectations. The original goal for the DOE funding of the ZP project Design, Test and Demonstration of Saturable Reactor High-Temperature Superconductor Fault Current Limiters was to stimulate the HTS wire industry with, first 1G, then 2G, HTS wire applications. Over the approximately 5 years of ZP's product development program, the amount of HTS

  20. Superconducting flux pump for high-temperature superconductor insert coils of NMR magnets

    Science.gov (United States)

    Jeong, S.; Lee, H.; Iwasa, Y.

    2002-05-01

    This paper describes a prototype flux pump recently operated at the MIT Francis Bitter Magnet Laboratory. The results of the prototype flux pump will be used in the development of a full-scale flux pump that will be coupled to a high-temperature superconductor (HTS) insert coil of a high-field NMR magnet. Such an HTS insert is unlikely to operate in persistent mode because of the conductor's low index (n). The flux pump can compensate for field decay in the HTS insert coil and make the insert operate effectively in persistent mode. The flux pump, comprised essentially of a transformer and two switches, all made of superconductor, transfers into the insert coil a fraction of a magnetic energy that is first introduced in the secondary circuit of the transformer by a current supplied to the primary circuit. A prototype flux pump has been designed, fabricated, and operated to demonstrate that a flux pump can indeed supply a small metered current into a load superconducting magnet. A current increment in the range of microamperes has been measured in the magnet after each pumping action. The superconducting prototype flux pump is made of Nb3Sn tape. The pump is placed in a gaseous environment above the liquid helium level to keep its heat dissipation from directly discharged in the liquid; the effluent helium vapor maintains the thermal stability of the flux pump. [This paper is also published in Advances in Cryogenic Engineering Volume 47A, AIP Conference Proceedings Volume 613, pp. 441-448.

  1. Electrochemical synthesis of alkali-intercalated iron selenide superconductors

    Institute of Scientific and Technical Information of China (English)

    申士杰; 应天平; 王刚; 金士锋; 张韩; 林志萍; 陈小龙

    2015-01-01

    Electrochemical method has been used to insert K/Na into FeSe lattice to prepare alkali-intercalated iron selenides at room temperature. Magnetization measurement reveals that KxFe2Se2 and NaxFe2Se2 are superconductive at 31 K and 46 K, respectively. This is the first successful report of obtaining metal-intercalated FeSe-based high-temperature superconductors using electrochemical method. It provides an effective route to synthesize metal-intercalated layered compounds for new superconductor exploration.

  2. HTS technology - Generating the future of offshore wind power

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Jens

    2010-09-15

    Superconductive generator design is going to become a real competitive alternative in the future. In general, superconductor design is the most competitive out of Direct Drive Systems and best fulfils the needs of the upcoming market - especially in the offshore market, where WECs with higher nominal power up to 10MW are required. Low weight, high reliability and the very good grid behaviour are the main advantages of the superconductor generator design and will lead to lower costs. The other systems are restricted to a smaller energy output range and / or onshore wind power production business.

  3. A HTS dc SQUID-NMR: fabrication of the SQUID and application to low-field NMR for fruit quality detection

    Science.gov (United States)

    Isingizwe Nturambirwe, J. Frédéric; Perold, Willem J.; Opara, Linus U.

    2014-06-01

    Superconducting Quantum Interference Devices (SQUIDs) have made the detection of low-field (LF) and ultra-low field nuclear magnetic resonance (ULF-NMR) a reality. The latter has been proven to be a potential tool for non-destructive quality testing of horticultural products, amongst many other applications. High-Temperature Superconductor (HTS) dc SQUIDS are likely to allow for the development of not only low-cost NMR systems but also prototypes that are mobile and easily maintainable. A HTS dc SQUID was manufactured on an YBCO thin film, using a novel laser based lithography method. The lithography was implemented by a new laser system developed in-house, as a model of low-cost lithography systems. The junctions of the dc SQUID were tested and displayed normal I-V characteristics in the acceptable range for the application. In order to determine the viability of low-field NMR for non-destructive quality measurement of horticultural products, a commercial HTS dc SQUID-NMR system was used to measure quality parameters of banana during ripening. The trend of color change and sugar increase of the banana during ripening were the most highly correlated attributes to the SQUID-NMR measured parameter, average T1 (spin-lattice relaxation time). Further studies were done, that involved processing of the NMR signal into relaxation time resolved spectra. A spectral signature of banana was obtained, where each peak is a T1 value corresponding to a proton pool, and is reported here. These results will potentially lead to deeper understanding of the quality of the samples under study.

  4. Current-carrying element based on second-generation high-temperature superconductor for the magnet system of a fusion neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Novikov, M. S., E-mail: mihailnovikov@yandex.ru; Ivanov, D. P., E-mail: Ivanov-DP@nrcki.ru, E-mail: denis.ivanov30@mail.ru; Novikov, S. I., E-mail: novikov-si@nrcki.ru; Shuvaev, S. A., E-mail: ser-shuvaev@yandex.ru, E-mail: sergey.shuvaev@phystech.edu [National Research Center Kurchatov Institute (Russian Federation)

    2015-12-15

    Application of current-carrying elements (CCEs) made of second-generation high-temperature superconductor (2G HTS) in magnet systems of a fusion neutron source (FNS) and other fusion devices will allow their magnetic field and thermodynamic stability to be increased substantially in comparison with those of low-temperature superconductor (LTS) magnets. For a toroidal magnet of the FNS, a design of a helical (partially transposed) CCE made of 2G HTS is under development with forced-flow cooling by helium gas, a current of 20–30 kA, an operating temperature of 10–20 K, and a magnetic field on the winding of 12–15 T (prospectively ∼20 T). Short-sized samples of the helical flexible heavy-current CCE are being fabricated and investigated; a pilot-line unit for production of long-sized CCE pieces is under construction. The applied fabrication technique allows the CCE to be produced which combines a high operating current, thermal and mechanical stability, manufacturability, and low losses in the alternating modes. The possibility of fabricating the CCE with the outer dimensions and values of the operating parameter required for the FNS (and with a significant margin) using already available serial 2G HTS tapes is substantiated. The maximum field of toroidal magnets with CCEs made of 2G HTS will be limited only by mechanical properties of the magnet’s casing and structure, while the thermal stability will be approximately two orders of magnitude higher than that of toroidal magnets with LTS-based CCEs. The helical CCE made of 2G HTS is very promising for fusion and hybrid electric power plants, and its design and technologies of production, as well as the prototype coils made of it for the FNS and other tokamaks, are worth developing now.

  5. Testability issues in Superconductor Electronics

    NARCIS (Netherlands)

    Kerkhoff, Hans G.; Arun, A.J.

    2004-01-01

    An emerging technology for solutions in high-end applications in computing and telecommunication is superconductor electronics. A system-level study has been carried out to verify the feasibility of DfT in superconductor electronics. In this paper, we present how this can be realized to monitor

  6. Coupling spin qubits via superconductors

    DEFF Research Database (Denmark)

    Leijnse, Martin; Flensberg, Karsten

    2013-01-01

    We show how superconductors can be used to couple, initialize, and read out spatially separated spin qubits. When two single-electron quantum dots are tunnel coupled to the same superconductor, the singlet component of the two-electron state partially leaks into the superconductor via crossed...... Andreev reflection. This induces a gate-controlled singlet-triplet splitting which, with an appropriate superconductor geometry, remains large for dot separations within the superconducting coherence length. Furthermore, we show that when two double-dot singlet-triplet qubits are tunnel coupled...... to a superconductor with finite charging energy, crossed Andreev reflection enables a strong two-qubit coupling over distances much larger than the coherence length....

  7. High-field flux mapping of (RE)BCO bulk superconductors-Development of an in situ scanning system

    Energy Technology Data Exchange (ETDEWEB)

    Withnell, T.D. [Superconductivity Group, Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)], E-mail: tdw25@cantab.net; Hari-Babu, N.; Ganney, I.; Dennis, A.; Cardwell, D.A. [Superconductivity Group, Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)

    2008-06-15

    Flux mapping of Y-Ba-Cu-O (YBCO) melt-processed, bulk high-temperature superconductors (HTS) is used to visualise the profile of trapped magnetic field on a magnetised sample and to measure the extent of current flow, and hence field penetration, within the bulk microstructure. Grain structure and defects below the sample surface are observed non-destructively by this technique. This paper outlines the design, development and construction of a novel, in situ Hall scanning system using an 8 T magnet and variable temperature insert (VTI). This system is then used to characterise the field trapping properties of bulk samples for different applied field history.

  8. The Basic Properties of PPLP for HTS DC Cable

    Science.gov (United States)

    Kim, W. J.; Kim, H. J.; Cho, J. W.; Kim, S. H.

    In order to develop high temperature superconducting (HTS) DC cable, it is important to understand the cooling system, high voltage insulation and materials at cryogenic temperature. Especially, the basic properties of insulating materials must be solved for the long life, reliability and compact of system. In this paper, we will discuss mainly on the electrical and the mechanical properties of polypropylene laminated paper (PPLP) in liquid nitrogen (LN2). The polarity effect of DC and impulse voltage, the volume resistivity and the space charge distribution and frost were studied. Furthermore, the mechanical properties such as tensile strength of PPLP at LN2 (77 K) and room temperature (300 K) were studied.

  9. SVPWM Techniques and Applications in HTS PMSM Machines Control

    Institute of Scientific and Technical Information of China (English)

    Zheng-Guang Wang; Jian-Xun Jin; You-Guang Guo; Jian-Guo Zhu

    2008-01-01

    This paper introduces the principle of space vector pulse width modulation (SVPWM), and discusses a method for implementing the SVPWM based on MATLAB/SIMULINK, as well as modeling of AC servo system with permanent magnet synchronous motor (PMSM). Simulation results show that the model is effective, and the method provides a frame of reference for software and hardware designs which can be applied in high temperature superconducting (HTS) flywheel energy storage system (FESS) and linear motor (LM).key wordsFlywheel energy storage system (FESS), linear motor (LM), modeling and simulation, permanent magnet synchronous motor (PMSM), space vector pulse width modulation (SVPWM).

  10. Issues relating to airborne applications of HTS SQUIDs

    CERN Document Server

    Foley, C P; Binks, R A; Lam, S H K; Du, J; Tilbrook, D L; Mitchell, E E; MacFarlane, J C; Lee, J B; Turner, R; Downey, M; Maddever, A

    2002-01-01

    Airborne application of HTS SQUIDs is the most difficult environment for their successful deployment. In order to operate with the sensitivity required for a particular application, there are many issues to be addressed such as the need for very wide dynamic range electronics, motion noise elimination, immunity to large changing magnetic fields and cultural noise sources. This paper reviews what is necessary to achieve an airborne system giving examples in geophysical mineral exploration. It will consider issues relating to device design and fabrication, electronics, dewar design, suspension system requirements and noise elimination methods.

  11. How resistive must grain boundaries in polycrystalline superconductors be, to limit J c?

    Science.gov (United States)

    Wang, Guanmei; Raine, Mark J.; Hampshire, Damian P.

    2017-10-01

    Although we can use misorientation angle to distinguish the grain boundaries that can carry high critical current density ({J}{{c}}) in high temperature superconductors (HTS) from those that cannot, there is no established normal state property equivalent. In this paper, we explore the superconducting and normal state properties of the grains and grain boundaries of polycrystalline YBa2Cu3O7-x (YBCO) using complementary magnetisation and transport measurements, and calculate how resistive grain boundaries must be to limit {J}{{c}} in polycrystalline superconductors. The average resistivity of the grain boundaries, {ρ }{{GB}}, in our micro- and nanocrystalline YBCO are 0.12 Ωm and 8.2 Ωm, values which are much higher than that of the grains ({ρ }{{G}}) and leads to huge {ρ }{{GB}}/{ρ }{{G}} values of 2 × 103 and 1.6 × 105 respectively. We find that the grain boundaries in our polycrystalline YBCO are sufficiently resistive that we can expect the transport {J}{{c}} to be several tens of orders of magnitude below the potential current density of the grains in our YBCO samples, as is found experimentally. Calculations presented show that increasing {J}{{c}} values by ˜2 orders of magnitude in high fields is still possible in all state-of-the-art technological high-field superconductors. We conclude: grain boundary engineering is unlikely to improve {J}{{c}} sufficiently in randomly aligned polycrystalline YBCO, to make it technologically useful for high-field applications; in low temperature superconducting intermetallics, such as Nb3Sn, large increases in {J}{{c}} may be achieved by completely removing the grain boundaries from these materials and, as is the case for thin films of Nb, Ba(FeCo)2As2 and HTS materials, by incorporating additional artificial pinning.

  12. High temperature superconductors

    CERN Document Server

    Paranthaman, Parans

    2010-01-01

    This essential reference provides the most comprehensive presentation of the state of the art in the field of high temperature superconductors. This growing field of research and applications is currently being supported by numerous governmental and industrial initiatives in the United States, Asia and Europe to overcome grid energy distribution issues. The technology is particularly intended for densely populated areas. It is now being commercialized for power-delivery devices, such as power transmission lines and cables, motors and generators. Applications in electric utilities include current limiters, long transmission lines and energy-storage devices that will help industries avoid dips in electric power.

  13. Antenna applications of superconductors

    Science.gov (United States)

    Hansen, R. C.

    1991-09-01

    The applicability of superconductors to antennas is examined. Potential implementations that are examined are superdirective arrays; electrically small antennas; tuning and matching of these two; high-gain millimeter-wavelength arrays; and kinetic inductance slow wave structures for array phasers and traveling wave array feeds. It is thought that superdirective arrays and small antennas will not benefit directly, but their tuning/matching networks will undergo major improvements. Miniaturization of antennas will not be aided, but much higher gain millimeter-wave arrays will be realizable. Kinetic inductance slow-wave lines appear advantageous for improved array phasers and time delay, as well as for traveling-wave array feeds.

  14. Reduction of Thermal Loss in HTS Windings by Using Magnetic Flux Deflection

    Science.gov (United States)

    Tsuzuki, K.; Miki, M.; Felder, B.; Koshiba, Y.; Izumi, M.; Umemoto, K.; Aizawa, K.; Yanamoto, T.

    Efforts on the generation of intensified magnetic flux have been made for the optimized shape of HTS winding applications. This contributes to the high efficiency of the rotating machines using HTS windings. Heat generation from the HTS windings requires to be suppressed as much as possible, when those coils are under operation with either direct or alternative currents. Presently, the reduction of such thermal loss generated by the applied currents on the HTS coils is reported with a magnetic flux deflection system. The HTS coils are fixed together with flattened magnetic materials to realize a kind of redirection of the flux pathway. Eventually, the magnetic flux density perpendicular to the tape surface (equivalent to the a-b plane) of the HTS tape materials is reduced to the proximity of the HTS coil. To verify the new geometry of the surroundings of the HTS coils with magnetic materials, a comparative study of the DC coil voltage was done for different applied currents in prototype field-pole coils of a ship propulsion motor.

  15. Design, construction and performance of an EMS-based HTS maglev vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Gu Chen [Applied Superconductivity Research Center, Department of Physics, Building LiZhai, Room 102, Tsinghua University, Beijing 100084 (China)]. E-mail: guchen@mail.tsinghua.edu.cn; Liu Menglin [Applied Superconductivity Research Center, Department of Physics, Building LiZhai, Room 102, Tsinghua University, Beijing 100084 (China); Xing Huawei [Department of Automation, Tsinghua University, Beijing 100084 (China); Zhou, Tong [Department of Automation, Tsinghua University, Beijing 100084 (China); Yin Wensheng [Department of Precision Instruments and Mechanology, Tsinghua University, Beijing 100084 (China); Zong Jun [Innova Superconductor Technology Co., Ltd., Beijing 100176 (China); Han Zhenghe [Applied Superconductivity Research Center, Department of Physics, Building LiZhai, Room 102, Tsinghua University, Beijing 100084 (China)

    2005-06-15

    A laboratory-scale EMS-based HTS maglev vehicle operating over a 1.5 m guideway has been successfully constructed. The fully integrated system consists of a vehicle chassis, four dependent magnetic circuits, four distance sensors, and control and power amplification circuits. As key component of the system, each magnetic circuit includes a U-shape iron core with one HTS coil forming each pole. Eight HTS coils made of Bi-2223 multi-filamentary tape were used to provide the magnetic motive force. Several questions relating to the unique characteristics of the HTS material in a controlled magnetic circuit are discussed. The most important consideration for such applications is that the anisotropic critical current of the Bi-2223/Ag tape depends strongly on the magnetic field. The commercially available FEA software ANSYS was used to simulate the field distribution along the magnetic circuit and HTS coil winding, and thereby identify how the magnetic circuit alters the field distribution in the coil winding and therefore also the critical current. A general optimization process is described for finding the best position in the U-shape iron core to hold the HTS coils. In this process the critical current of the HTS tape and the force-current characteristic of the magnetic circuit are considered synthetically. The results demonstrate the feasibility and stability of HTS material in a typical maglev system and other similar controllability applications.

  16. Magnetic excitations in iron chalcogenide superconductors.

    Science.gov (United States)

    Kotegawa, Hisashi; Fujita, Masaki

    2012-10-01

    Nuclear magnetic resonance and neutron scattering experiments in iron chalcogenide superconductors are reviewed to make a survey of the magnetic excitations in FeSe, FeSe1-x Te x and alkali-metal-doped Ax Fe2-y Se2 (A = K, Rb, Cs, etc). In FeSe, the intimate relationship between the spin fluctuations and superconductivity can be seen universally for the variations in the off-stoichiometry, the Co-substitution and applied pressure. The isovalent compound FeTe has a magnetic ordering with different wave vector from that of other Fe-based magnetic materials. The transition temperature Tc of FeSe increases with Te substitution in FeSe1-x Te x with small x, and decreases in the vicinity of the end member FeTe. The spin fluctuations are drastically modified by the Te substitution. In the vicinity of the end member FeTe, the low-energy part of the spin fluctuation is dominated by the wave vector of the ordered phase of FeTe; however, the reduction of Tc shows that it does not support superconductivity. The presence of same wave vector as that of other Fe-based superconductors in FeSe1-x Te x and the observation of the resonance mode demonstrate that FeSe1-x Te x belongs to the same group as most of other Fe-based superconductors in the entire range of x, where superconductivity is mediated by the spin fluctuations whose wave vector is the same as the nesting vector between the hole pockets and the electron pockets. On the other hand, the spin fluctuations differ for alkali-metal-doped Ax Fe2-y Se2 and FeSe or other Fe-based superconductors in their wave vector and strength in the low-energy part, most likely because of the different Fermi surfaces. The resonance mode with different wave vector suggests that Ax Fe2-y Se2 has an exceptional superconducting symmetry among Fe-based superconductors.

  17. First tests of twisted-pair HTS 1 kA range cables for use in superconducting links

    CERN Document Server

    Ballarino, A; Hurte, J; Sitko, M; Willering, G

    2011-01-01

    The requirement at CERN for 1 kA range High Temperature Superconducting (HTS) cables optimized for long electrical transfer has led to the design and assembly of a novel type of cable that can be made from pre-reacted MgB2, Bi-2223 or YBCO tapes. The cable consists of an assembly of twisted pairs, each of which is made from three superconducting tapes with the required copper stabilizer. The twisted pair cable is designed to transfer a DC current of ± 600 A in helium gas environment. The paper reports on the results of the electrical tests performed on twisted-pair cables of identical structure and made from commercially available MgB2, Bi-2223 and YBCO tapes. The twist pitch of the cables is adapted to match the mechanical properties of the different superconductors. Critical current tests were performed at both liquid helium and liquid nitrogen temperature. The electrical performance of several cables made from different conductors is reported and compared.

  18. Development of REBCO HTS Magnet of Magnetic Bearing for Large Capacity Flywheel Energy Storage System

    Science.gov (United States)

    Mukoyama, Shinichi; Matsuoka, Taro; Furukawa, Makoto; Nakao, Kengo; Nagashima, Ken; Ogata, Masafumi; Yamashita, Tomohisa; Hasegawa, Hitoshi; Yoshizawa, Kazuhiro; Arai, Yuuki; Miyazaki, Kazuki; Horiuchi, Shinichi; Maeda, Tadakazu; Shimizu, Hideki

    A flywheel energy storage system (FESS) is a promising electrical storage system that moderates fluctuation of electrical power from renewable energy sources. The FESS can charge and discharge the surplus electrical power repetitively with the rotating energy. Particularly, the FESS that utilizes a high temperature superconducting magnetic bearing (HTS bearing) is lower loss than conventional FESS that has mechanical bearing, and has property of longer life operation than secondary batteries. The HTS bearing consists of a HTS bulk and double-pancake coils used 2nd generation REBCO wires. In the development, the HTS double-pancake coils were fabricated and were provided for a levitation test to verify the possibility of the HTS bearing. We successfully confirmed the magnetic field was achieved to design value, and levitation force in the configuration of one YBCO bulk and five double pan-cake coils was obtained to a satisfactory force of 39.2 kN (4 tons).

  19. Thermal analysis of HTS air-core transformer used in voltage compensation type active SFCL

    Science.gov (United States)

    Song, M.; Tang, Y.; Li, J.; Zhou, Y.; Chen, L.; Ren, L.

    2010-11-01

    The three-phase voltage compensation type active superconducting fault current limiter (SFCL) is composed of three HTS air-core transformers and a three-phase four-wire Pulse Width Modulation (PWM) converter. The primary winding of the each phase HTS air-core transformer is in series with the main system, and the second winding is connected with the PWM converter. The single-phase conduction-cooled HTS air-core transformer is consisting of four double-pancakes wound by the Bi2223/Ag tape. In this paper, according to the electromagnetic analysis on the single-phase HTS air-core transformer, its AC loss corresponding to different operation modes is calculated. Furthermore, the thermal behaviors are studied by the time-stepping numerical simulations. On the basis of the simulation results, the related problems with the HTS air-core transformer's thermal stability are discussed.

  20. Large Scale Assembly and Characterization of BI-2223 HTS Conductors

    CERN Document Server

    Ballarino, Amalia; Mathot, Serge; Taylor, T; Brambilla, R

    2007-01-01

    The powering of the LHC machine requires more than 1000 High Temperature Superconducting (HTS) current leads. These leads contain, at their cold end, HTS conductors made of stacks of Bi-2223 tape with gold-doped silver matrix. CERN specified and purchased 31 km of this material, which was delivered on spools in unit lengths of 100 to 300 m. On reception the tape was inspected, cut into short length and vacuum soldered into stacks. All stacks were characterized in liquid nitrogen using a measuring procedure and set-up specifically developed for this purpose. Contact resistance values and critical currents at different electric field criteria were measured, from which the n-values have been extrapolated from the experimental V-I characteristics. This paper reports on the assembly and electrical characterization (up to 800 A) of more than ten thousand Bi-2223 stacks. Three types of stack were made from tape from two manufacturers. The assembly and soldering procedures and the set-up for the series electrical cha...

  1. Study on magnetic gene transfer using HTS bulk magnet

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, Kota, E-mail: nakagawa@qb.see.eng.osaka-u.ac.jp [Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871 (Japan); Ohaku, Yoshihiro; Tamada, Junya; Mishima, Fumihito; Akiyama, Yoko [Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871 (Japan); Osako, Mariana Kiomy; Nakagami, Hironori [Graduate School of Medicine, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871 (Japan); Nishijima, Shigehiro [Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871 (Japan)

    2013-11-15

    Highlights: •DNA–magnetite complexes were prepared as ferromagnetic DNA carrier. •The condition of magnetic field to suppress the diffusion was found by calculation. •The result of model experiment showed the validity of the calculated value. •The results of in vivo experiments showed that the amount of gene expression was significantly increased by magnetic field. -- Abstract: This study aimed to realize local and high-efficient gene expression by suppressing the diffusion of ferromagnetic DNA carriers in a strong magnetic field generated by HTS bulk magnet. DNA–magnetite complexes were prepared as ferromagnetic DNA carrier and the magnetic gene transfer using the DNA carriers was examined. From the results of the simulation and the model experiment, it was shown that the particle diffusion was suppressed within 10 mm in diameter by the magnetic field at 20 mm above the HTS bulk magnet. The results of in vivo experiments showed that the amount of gene expression was significantly increased by magnetic field.

  2. The radio-frequency HTS SQUID for magnetic microscopy

    CERN Document Server

    Khvostov, S S; Garbuz, A S; Shnyrkov, V I

    2003-01-01

    The spectral density of magnetic flux noise S subPHI sup 1 sup / sup 2 (f) for HTS RF SQUIDs with a pumping frequency of 390-457 Mhz within triple-layer permalloy and superconducting shields are investigated. The superconducting interferometers of 100 centre dot 100 mm, are fabricated by the thin film technology with ramp-edge type Josephson junctions YBaCuO-PrBaCuO-YBaCuO. It is shown that with a cooled preamplifier the energy resolution of SQUIDs makes up to 4 centre dot 10 sup - sup 3 sup 0 J/Hz at 'white' noise (at frequencies above 1 kHz) and is mainly defined by inherent noise of the HTS interferometer and the shields. At low frequencies the noises related to exterior fields that penetrate directly into the shields, are dominant. At frequencies above 1 kHz, the ferromagnetic antenna of the SQUID microscope increases the intrinsic noise of the magnetometer up to 8 centre dot 10 sup - sup 3 sup 0 J/Hz.

  3. 5 MJ flywheel based on bulk HTS magnetic suspension

    Science.gov (United States)

    Poltavets, V.; Kovalev, K.; Ilyasov, R.; Glazunov, A.; Maevsky, V.; Verzbitsky, L.; Akhmadyshev, V.; Shikov, A.

    2014-05-01

    Nowadays the flywheel energy storage systems (FES) are developed intensively as uninterruptible power supply (UPS) devices for on-land and transport (especially airborne) applications worldwide. This work is devoted to the FES with magnetic suspension on the base of bulk HTS YBCO elements and permanent magnets. The developed FES is intended to be used as UPS in Russian atomic industry in case of an emergency. For the successful design of the FES the following questions should be solved: design of the motor/generator, design of the rotor (flywheel), design of the bearing system, design of the control system and system of power load matching, design of the cooling system. The developed small-scale FES with the stored energy 0.5 MJ was used to solve these basic questions. The elaborated FES consists of the synchronous electric machine with permanent magnets, the solid flywheel with axial magnetic suspension on the base of YBCO bulks and permanent magnets, the system of control and power load matching, and the system of liquid nitrogen cooling. The results of theoretical modeling of different schematics of magnetic suspension and experimental investigations of the constructed FES are presented. The design of the future full-scale FES with the stored energy ~5 MJ and output power up to 100 kW is described. The test results of the flywheel rotor and HTS magnetic suspension of 5 MJ FES are presented. This work is done under support of Rosatom within the frames of Russian Project "Superconducting Industry"

  4. Flux pinning in superconductors

    CERN Document Server

    Matsushita, Teruo

    2014-01-01

    The book covers the flux pinning mechanisms and properties and the electromagnetic phenomena caused by the flux pinning common for metallic, high-Tc and MgB2 superconductors. The condensation energy interaction known for normal precipitates or grain boundaries and the kinetic energy interaction proposed for artificial Nb pins in Nb-Ti, etc., are introduced for the pinning mechanism. Summation theories to derive the critical current density are discussed in detail. Irreversible magnetization and AC loss caused by the flux pinning are also discussed. The loss originally stems from the ohmic dissipation of normal electrons in the normal core driven by the electric field induced by the flux motion. The readers will learn why the resultant loss is of hysteresis type in spite of such mechanism. The influence of the flux pinning on the vortex phase diagram in high Tc superconductors is discussed, and the dependencies of the irreversibility field are also described on other quantities such as anisotropy of supercondu...

  5. Flux Pinning in Superconductors

    CERN Document Server

    Matsushita, Teruo

    2007-01-01

    The book covers the flux pinning mechanisms and properties and the electromagnetic phenomena caused by the flux pinning common for metallic, high-Tc and MgB2 superconductors. The condensation energy interaction known for normal precipitates or grain boundaries and the kinetic energy interaction proposed for artificial Nb pins in Nb-Ti, etc., are introduced for the pinning mechanism. Summation theories to derive the critical current density are discussed in detail. Irreversible magnetization and AC loss caused by the flux pinning are also discussed. The loss originally stems from the ohmic dissipation of normal electrons in the normal core driven by the electric field induced by the flux motion. The readers will learn why the resultant loss is of hysteresis type in spite of such mechanism. The influence of the flux pinning on the vortex phase diagram in high Tc superconductors is discussed, and the dependencies of the irreversibility field are also described on other quantities such as anisotropy of supercondu...

  6. Materials design for new superconductors.

    Science.gov (United States)

    Norman, M R

    2016-07-01

    Since the announcement in 2011 of the Materials Genome Initiative by the Obama administration, much attention has been given to the subject of materials design to accelerate the discovery of new materials that could have technological implications. Although having its biggest impact for more applied materials like batteries, there is increasing interest in applying these ideas to predict new superconductors. This is obviously a challenge, given that superconductivity is a many body phenomenon, with whole classes of known superconductors lacking a quantitative theory. Given this caveat, various efforts to formulate materials design principles for superconductors are reviewed here, with a focus on surveying the periodic table in an attempt to identify cuprate analogues.

  7. Spin manipulation in nanoscale superconductors.

    Science.gov (United States)

    Beckmann, D

    2016-04-27

    The interplay of superconductivity and magnetism in nanoscale structures has attracted considerable attention in recent years due to the exciting new physics created by the competition of these antagonistic ordering phenomena, and the prospect of exploiting this competition for superconducting spintronics devices. While much of the attention is focused on spin-polarized supercurrents created by the triplet proximity effect, the recent discovery of long range quasiparticle spin transport in high-field superconductors has rekindled interest in spin-dependent nonequilibrium properties of superconductors. In this review, the experimental situation on nonequilibrium spin injection into superconductors is discussed, and open questions and possible future directions of the field are outlined.

  8. Materials design for new superconductors

    Science.gov (United States)

    Norman, M. R.

    2016-07-01

    Since the announcement in 2011 of the Materials Genome Initiative by the Obama administration, much attention has been given to the subject of materials design to accelerate the discovery of new materials that could have technological implications. Although having its biggest impact for more applied materials like batteries, there is increasing interest in applying these ideas to predict new superconductors. This is obviously a challenge, given that superconductivity is a many body phenomenon, with whole classes of known superconductors lacking a quantitative theory. Given this caveat, various efforts to formulate materials design principles for superconductors are reviewed here, with a focus on surveying the periodic table in an attempt to identify cuprate analogues.

  9. Observation of Magnetic Signals from Earthquake Faulting Using High-resolution HTS-SQUID Magnetometer: Feasibility of Super-early Warning of Earthquakes

    Science.gov (United States)

    Katori, Y.; Okubo, K.; Hato, T.; Tsukamoto, A.; Tanabe, K.; Onishi, N.; Furukawa, H.; Isogami, S.; Takeuchi, N.

    2015-12-01

    Electromagnetic changes associated with earthquakes have been investigated previously. Our research group has also employed the magnetometers for seismomagnetic observations since March 2004. Our observation site happened to be situated at an epicentral distance of 26 km from the 2008 Iwate-Miyagi Nairiku earthquake ofM7.2, NE Japan. In this earthquake, we have reported successful observation of "co-faulting" Earth's magnetic field changes (Okubo et al., 2011 EPSL). Magnetic fields began to change almost simultaneously with the onset of the earthquake rupture and grew before the first P wave arrival. Such magnetic signals are most probably generated by the changing stress field due to earthquake rupturing, i.e. the piezomagnetic effect. On the other hand, this observation result suggested that the geomagnetic variation signal accompanying fault movement, whose sources are the piezomagnetic effects, is very small. The observed change of geomagnetic field might be approximately less than several hundred pico-tesla. Therefore, to obtain more observation data of "co-faulting" magnetic field change, development of a higher-sensitive magnetometer system is very important. Then, our research group tried to develop the HTS-SQUID (high-temperature-superconductor based superconducting-quantum-interference-device) magnetometer systems for high-resolution observation of Earth's magnetic field. Since March 2012 we have introduced long-term precise geomagnetic observations using the HTS-SQUID magnetometer system Unit No.1 (mark I) at Iwaki observation site (IWK) in Fukushima, Japan. Additionally, since October 2014, we have also introduced the new HTS- SQUID magnetometer system Unit No.2 (mark II). The sampling interval of the magnetometers is 0.02 sec (50Hz). The system clock has been synchronized by use of GPS signals. A high-resolution accelerometer is also installed at observation point. In this study, we show the observation results of geomagnetic field changes associated

  10. 高温超导滤波器应用的探索与实践%The applications of HTS filters: exploration and practice

    Institute of Scientific and Technical Information of China (English)

    孙亮; 黎红; 张雪强; 李春光; 张强; 王佳; 边勇波; 何豫生

    2012-01-01

    Since the discovery of superconductivity in 1911, new materials have been discovered, new mechanisms revealed, and new theories developed. At the same time, remarkable achievements have been made in the applications of superconductor. Among all the applications, microwave filters and microwave receiver frontend sub-systems, which benefit from the small surface resistance of the superconductor materials, have attracted intensive interests all over the world, and great progress has been made in their applications. Our group has been devoting to the related research and made great results in this area for a long time. In this review, we will introduce a new design method for high temperature superconductor (HTS) filters, and discuss the applications of HTS filters and sub-systems in mobile communications, meteorological radars, radio astronomy, satellite application and other areas, along with the researches performed by our group in recent years.%自1911年发现超导电性以来,在不断发现新材料,揭示新机理,发展新理论的同时,超导应用也取得了引人瞩目的进展,其中利用超导材料微波损耗很低的特性研制的微波滤波器和微波接收机前端子系统得到了世界各国的重视,并在实际应用中取得了重要成果.本研究组长期从事该领域的研究,并已取得一些成果.该文将从超导滤波器的创新设计方法入手,结合研究组近些年开展的工作,介绍高温超导滤波器及其子系统在无线通讯、气象雷达、射电天文以及空间技术等领域中的应用.

  11. Manufacturing a Superconductor in School.

    Science.gov (United States)

    Barrow, John

    1989-01-01

    Described is the manufacture of a superconductor from a commercially available kit using equipment usually available in schools or easily obtainable. The construction is described in detail including equipment, materials, safety procedures, tolerances, and manufacture. (Author/CW)

  12. The insulation coordination and surge arrester design for HTS cable system in Icheon substation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hansang, E-mail: Hansang80@korea.ac.kr [School of Railway and Electrical Engineering, Kyungil University, Hayang-eup, Gyeongsan-si, Gyeongsangbuk-do 712-701 (Korea, Republic of); Yoon, Dong-Hee [Department of New and Renewable Energy, Kyungil University, Hayang-eup, Gyeongsan-si, Gyeongsangbuk-do 712-701 (Korea, Republic of); Lee, Seung-Ryul [Korea Electrotechnology Research Institute, Naeson-dong, Uiwang-si, Gyeonggi-do 437-080 (Korea, Republic of); Yang, Byeong-Mo [Korea Electric Power Research Institute, Munji-dong, Yuseong-gu, Daejeon 305-760 (Korea, Republic of); Jang, Gilsoo, E-mail: gjang@korea.ac.kr [School of Electrical Engineering, Korea University, Anam-dong 5-ga, Seongbuk-gu, Seoul 136-713 (Korea, Republic of)

    2013-01-15

    Highlights: ► It is necessary to study lightning response of the HTS cable. ► The analytic model has been developed for the HTS cable in the Icheon substation. ► Well-designed surge arrester has been verified through PSCAD/EMTDC simulations. -- Abstract: This paper proposes an insulation coordination and surge arrester design for HTS (High-Temperature Superconducting) cable system in Icheon substation in Korea. In the aspect of the economic analysis, since the HTS cable is very expensive, the insulation coordination to prevent the dielectric breakdown caused by the lightning surge should be considered carefully. Also, in the aspect of the power system reliability, since the HTS cable has much more capacity compared than conventional power cables and the ripple effect from the HTS cable failure may lead to the wide area blackout, an intensive study for insulation coordination from lightning surge is one of the most important considerations. In this paper, the insulation coordination for lightning surge is verified using HTS cable and power equipment models and the design of the proper surge arrester is proposed.

  13. Transient analysis of an HTS DC power cable with an HVDC system

    Energy Technology Data Exchange (ETDEWEB)

    Dinh, Minh-Chau, E-mail: thanchau7787@gmail.com [Department of Electrical Engineering, Changwon National University, 9 Sarim-Dong, Changwon 641-773 (Korea, Republic of); Ju, Chang-Hyeon; Kim, Jin-Geun; Park, Minwon [Department of Electrical Engineering, Changwon National University, 9 Sarim-Dong, Changwon 641-773 (Korea, Republic of); Yu, In-Keun, E-mail: yuik@cwnu.ac.kr [Department of Electrical Engineering, Changwon National University, 9 Sarim-Dong, Changwon 641-773 (Korea, Republic of); Yang, Byeongmo [Korea Electric Power Research Institute, 105 Munji-Ro, Yuseong-Gu, Daejon 305-760 (Korea, Republic of)

    2013-11-15

    Highlights: •A model of an HTS DC power cable was developed using real time digital simulator. •The simulations of the HTS DC power cable in connection with an HVDC system were performed. •The transient analysis results of the HTS DC power cable were presented. -- Abstract: The operational characteristics of a superconducting DC power cable connected to a highvoltage direct current (HVDC) system are mainly concerned with the HVDC control and protection system. To confirm how the cable operates with the HVDC system, verifications using simulation tools are needed. This paper presents a transient analysis of a high temperature superconducting (HTS) DC power cable in connection with an HVDC system. The study was conducted via the simulation of the HVDC system and a developed model of the HTS DC power cable using a real time digital simulator (RTDS). The simulation was performed with some cases of short circuits that may have caused system damage. The simulation results show that during the faults, the quench did not happen with the HTS DC power cable because the HVDC controller reduced some degree of the fault current. These results could provide useful data for the protection design of a practical HVDC and HTS DC power cable system.

  14. Development of the Current Bypassing Methods into the Transverse Direction in Non-insulation HTS Coils

    Science.gov (United States)

    Tanaka, K.; Kim, S. B.; Ikoma, H.; Kanemoto, D.

    In the case of motors and generators, the benefits of using high temperature superconducting (HTS) coils can be represented by the reduction of 50% in both losses and sizes compared to conventional machines. However, it is hard to establish quench detection and protection devices for the HTS coils applied to the rotors of motors and generators. So, the stability of the coils is lower than for the quiescent coils applied to NMR, MRI and so on. Therefore, it is important to improve the self-protection ability of HTS coils. We have studied the methods to improve the self-protection ability of HTS coils by removing the layer-to-layer insulation and inserting metal tape instead of the electrical insulation. The operating current in the non-insulated HTS coil was bypassed into the transverse direction by the generated normal region because of their electrical contact among the winding. In this study, we examined the method to control the current bypassing on layer-to-layer for controlling the inductance of the non-insulated HTS coil. The current bypassing properties on non-insulated HTS coil wound with 2G wires will be discussed.

  15. Fabrication and test of an axial-field HTS rotating machine with integrated magnetic coupling

    Science.gov (United States)

    Dolisy, B.; Mezani, S.; Lubin, T.; Lévêque, J.

    2017-03-01

    High temperature superconducting (HTS) electrical machines have high torque density with a very high efficiency. Torque tubes are usually used to transmit the torque from the cold to the warm environment which results in thermal losses and mechanical problems. To overcome these difficulties, we propose to transmit the torque of the HTS machine through an integrated HTS magnetic coupling. A prototype has been constructed and tested showing the effectiveness of the proposed solution. The machine and the coupling share the same HTS rotor while the torque produced by the machine is transmitted to the load via a permanent magnets rotor. This solution allows the reduction of the thermal losses and a natural protection against overload during fault. The electromagnetic design is carried out using 3D finite elements (FE). The HTS material electrical behavior is described using a power law so it was possible to determine the operating current of the HTS coils of the device. Many test results such as U(I) curves of the HTS coils, static torque, back-EMF and on-load characteristics are presented and checked by the FE computations.

  16. Race-track coils for a 3 MW HTS ship motor

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, E., E-mail: ueno-eisaku@sei.co.jp; Kato, T.; Hayashi, K.

    2014-09-15

    Highlights: • Sumitomo Electric manufactured the HTS field coils for a 3 MW HTS ship motor. • The motor was developed and successfully passed the loading test by Kawasaki Heavy. • We tested and obtained the basic data to evaluate the 20-year durability of coils. - Abstract: Since the discovery of high-temperature superconductivity (HTS), Sumitomo Electric has been developing silver-sheathed Bi2223 superconducting wire and products. Ship propulsion motors are one of the most promising applications of HTS. Sumitomo Electric Industries, Ltd. (SEI) has recently manufactured 24 large racetrack coils, using 70 km long DI-BSCCO wires, for use in a 3 MW HTS motor developed by Kawasaki Heavy Industries, Ltd. (KHI). The 3 MW HTS motor, using our newly developed racetrack coils, has successfully passed the loading test. It is particularly important that the HTS field coils used in ship propulsion motors can withstand the expansive forces repeatedly applied to them. As racetrack type coils have straight sections, the support mechanism they require to withstand expansive forces is very different from that of circular coils. Therefore, we ran tests and obtained the basic data to evaluate the 20-year durability of racetrack coils against the repeatedly applied expansive forces expected in domestic ship propulsion motors.

  17. Magnetizing of permanent magnets using HTS bulk magnets

    Science.gov (United States)

    Oka, Tetsuo; Muraya, Tomoki; Kawasaki, Nobutaka; Fukui, Satoshi; Ogawa, Jun; Sato, Takao; Terasawa, Toshihisa

    2012-01-01

    A demagnetized Nd-Fe-B permanent magnet was scanned just above the magnetic pole which contains the HTS bulk magnet generating a magnetic field of 3.27 T. The magnet sample was subsequently found to be fully magnetized in the open space of the static magnetic fields. We examined the magnetic field distributions when the magnetic poles were scanned twice to activate the magnet plate inversely with various overlap distances between the tracks of the bulk magnet. The magnetic field of the "rewritten" magnet reached the values of the magnetically saturated region of the material, showing steep gradients at the border of each magnetic pole. As a replacement for conventional pulse field magnetizing methods, this technique is proposed to expand the degree of freedom in the design of electromagnetic devices, and is proposed as a novel practical method for magnetizing rare-earth magnets, which have excellent magnetic performance and require intense fields of more than 3 T to be activated.

  18. Design of HTS transmit filter using step impedance resonators

    Energy Technology Data Exchange (ETDEWEB)

    Sekiya, N., E-mail: nsekiya@yamanashi.ac.j [University of Yamanashi, 4-3-11 Takeda, Kofu 400-8511 (Japan); Nakagawa, Y. [University of Yamanashi, 4-3-11 Takeda, Kofu 400-8511 (Japan); Ohshima, S. [Yamagata University, 4-3-16 Johnan, Yonezawa 992-8510 (Japan)

    2010-11-01

    We have designed a high-temperature superconducting (HTS) transmit filter with step impedance resonators (SIRs). A transmit filter using half-wavelength straight-line resonators requires substantial spacing between adjacent resonators. This means that the filter needs a large substrate and that the number of poles is limited. Using SIRs overcomes this problem because SIRs are compact and have weak coupling. An electromagnetic simulator based on the moment method was used to design the SIR filter, which has a center frequency of 5 GHz and a bandwidth of 120 MHz. Simulation showed that it is approximately 19% smaller than a conventional half-wavelength straight-line resonator filter. Additionally, the maximum surface current is approximately 17% less than that of the conventional filter.

  19. Multi-Pole HTS Generators for Direct Drive Wind Turbines

    DEFF Research Database (Denmark)

    Jensen, Bogi Bech; Abrahamsen, Asger Bech; Seiler, Eugen;

    on two different types of coated conductor. In the specific design the allowable current density was 300A/mm^2 for tape 1 and 70A/mm^2 for tape 2. The design is analytical, based on magnetic circuit analysis, which is validated by finite element modelling. The conclusion is that the either price...... laboratory (NREL). The emphasis of the investigation is on cost and mass, where the cost limit for the active material is set at €1M; the active mass limit is set at 40 tons; and the outer diameter is 4.2 meters. The allowable engineering current densities have been estimated by measuring the magnetization...... or the performance of the coated conductor has to improve significantly (by a factor of 10 or more) in order for HTS generators to become feasible in direct drive offshore wind turbines. This price/performance improvement is not unrealistic in the coming decade. Additionally the reliability of such machines...

  20. Simulation and Test for the Thermal Behaviour of a Prototype Synchronous Generator with HTS Armature Windings

    Science.gov (United States)

    Yu, X.-Y.; Qu, T.-M.; Song, P.; Li, L.-N.; Chen, D.-X.; Han, Z.

    A synchronous generator prototype with HTS armature windings and a permanent magnet rotor (HTS-PM) was developed. The temperature evolution during cooling and operation processes of the HTS coils was analyzed by finite element method (FEM). The simulated results coincided well with the temperature measurement data acquired by PT-100 sensors. Cooling time, terminal temperature, contact thermal conductivity, during cooling, as well as the proportion between real and calculated iron loss, contact thermal conductivity, at various rotating speeds during operation, were worked out using the FEM model.

  1. Static and dynamic stability of the guidance force in a side-suspended HTS maglev system

    Science.gov (United States)

    Zhou, Dajin; Cui, Chenyu; Zhao, Lifeng; Zhang, Yong; Wang, Xiqing; Zhao, Yong

    2017-02-01

    The static and dynamic stability of the guidance force in a side-suspended HTS-PMG (permanent magnetic guideway) system were studied theoretically and experimentally. It is found that there are two types of guidance force that exist in the HTS-PMG system, which are sensitive to the levitation gap and the arrangement of YBCO bulks around the central axis of the PMG. An optimized YBCO array was used to stabilize the system, which enabled a side-suspended HTS-PMG maglev vehicle to run stably at 102 km h-1 on a circular test track with 6.5 m in diameter.

  2. Simulation and measurement of a Ka-band HTS MMIC Josephson junction mixer

    Science.gov (United States)

    Zhang, Ting; Pegrum, Colin; Du, Jia; Guo, Yingjie Jay

    2017-01-01

    We report modeling and simulation results for a Ka band high-temperature superconducting (HTS) monolithic microwave integrated circuit (MMIC) Josephson junction mixer. A Verilog-A model of a Josephson junction is established and imported into the system simulator to realize a full HTS MMIC circuit simulation containing the HTS passive circuit models. Impedance matching optimization between the junction and passive devices is investigated. Junction DC I-V characteristics, current and local oscillator bias conditions and mixing performance are simulated and compared with the experimental results. Good agreement is obtained between the simulation and measurement results.

  3. Study of damping in 5 kWh superconductor flywheel energy storage system using a piezoelectric actuator

    Science.gov (United States)

    Jang, H. K.; Song, D.; Kim, S. B.; Han, S. C.; Sung, T. H.

    2012-05-01

    A 5 kWh superconductor flywheel energy storage system (SFES) has advantages in terms of high electrical energy density, environmental affinity and long life. However, the SFES has disadvantage that electromagnetic damper is needed because superconducting bearings do not have enough damping coefficient. The purpose of this experiment is to develop a method of damping the vibration of the SFES. A piezoelectric actuator was attached to a superconducting bearing system for feasibility test in order to make it as a damper of the SFES. For this experiment, a cylindrical permanent magnet (PM) 40 mm in diameter and 10 mm height was used as a rotor, a high-temperature superconductor bulk (HTS bulk) with dimensions 40 mm × 40 mm × 15 mm was used as a stator, and two vibration exciters (an upper and a lower vibration exciter) and a piezoelectric actuator were used. The PM was fixed on the upper vibration exciter. The HTS bulk was fixed on either the lower vibration exciter to test for damping in the feasibility test, or on the piezoelectric actuator for the actual SFES. The conditions of this experiment included various voltage outputs of a power amplifier to the lower vibration exciter, moving distances of the piezoelectric actuator which are displacements of the HTS bulk, and phase differences between the upper and lower vibration exciter or the piezoelectric actuator. The damping feasibility test was conducted with a 300 μm gap between the PM and HTS bulk with a PM vibration of 30 μm. For the actual SFES test, the gap between the PM and HTS bulk was 1.6 mm and the PM vibration was 25 μm. The following conditions were conducted to optimize: an appropriate voltage input to the lower vibration exciter or a displacement of piezoelectric actuator and an appropriate phase difference. When the piezoelectric actuator was used, the damping effect was greatly improved up to 92.32% which a displacement of damped PM was 1.92 μm.

  4. Study of damping in 5 kWh superconductor flywheel energy storage system using a piezoelectric actuator

    Energy Technology Data Exchange (ETDEWEB)

    Jang, H.K.; Song, D.; Kim, S.B. [Hanyang University, 17 Haengdang-Dong, Seongdong-Gu, Seoul 133-791 (Korea, Republic of); Han, S.C. [Korea Electric Power Research Institute, 103-16 Munji-Ro, Yuseong-Gu, Daejeon 305-380 (Korea, Republic of); Sung, T.H., E-mail: sungth@hanyang.ac.kr [Hanyang University, 17 Haengdang-Dong, Seongdong-Gu, Seoul 133-791 (Korea, Republic of)

    2012-05-15

    A 5 kWh superconductor flywheel energy storage system (SFES) has advantages in terms of high electrical energy density, environmental affinity and long life. However, the SFES has disadvantage that electromagnetic damper is needed because superconducting bearings do not have enough damping coefficient. The purpose of this experiment is to develop a method of damping the vibration of the SFES. A piezoelectric actuator was attached to a superconducting bearing system for feasibility test in order to make it as a damper of the SFES. For this experiment, a cylindrical permanent magnet (PM) 40 mm in diameter and 10 mm height was used as a rotor, a high-temperature superconductor bulk (HTS bulk) with dimensions 40 mm Multiplication-Sign 40 mm Multiplication-Sign 15 mm was used as a stator, and two vibration exciters (an upper and a lower vibration exciter) and a piezoelectric actuator were used. The PM was fixed on the upper vibration exciter. The HTS bulk was fixed on either the lower vibration exciter to test for damping in the feasibility test, or on the piezoelectric actuator for the actual SFES. The conditions of this experiment included various voltage outputs of a power amplifier to the lower vibration exciter, moving distances of the piezoelectric actuator which are displacements of the HTS bulk, and phase differences between the upper and lower vibration exciter or the piezoelectric actuator. The damping feasibility test was conducted with a 300 {mu}m gap between the PM and HTS bulk with a PM vibration of 30 {mu}m. For the actual SFES test, the gap between the PM and HTS bulk was 1.6 mm and the PM vibration was 25 {mu}m. The following conditions were conducted to optimize: an appropriate voltage input to the lower vibration exciter or a displacement of piezoelectric actuator and an appropriate phase difference. When the piezoelectric actuator was used, the damping effect was greatly improved up to 92.32% which a displacement of damped PM was 1.92 {mu}m.

  5. Magnetic Excitations from Stripes in Cuprate Superconductors

    Science.gov (United States)

    Tranquada, J. M.; Woo, H.; Perring, T. G.; Goka, H.; Gu, G. D.; Xu, G.; Fujita, M.; Yamada, K.

    2004-03-01

    While it is generally believed that antiferromagnetic spin excitations play a significant role in the pairing mechanism of copper-oxide superconductors [1], the nature of the magnetic excitations themselves remains a matter of controversy. Recent measurements of the dispersion of spin excitations in superconducting YBa_2Cu_3O_6+x (YBCO) have attracted much attention. Here we present the results of comprehensive inelastic neutron scattering measurements of the momentum- and energy-dependent spectra of the magnetic fluctuations in La_0.875Ba_0.125CuO_4, which exhibits inhomogeneous, charge-stripe order. We will also point out universalities and differences in the magnetic excitation spectra compared to related charge-stripe ordered compounds and high-temperature superconductors, including La_2-xSr_xNiO4 and YBCO. JMT, HW, GDG and GX are supported by U.S. Department of Energy contract # DE-AC02-98CH1088 [1] J. Orenstein and A. J. Millis, Science 288, 468 (2000).

  6. Broad-Based Search for New and Practical Superconductors

    Science.gov (United States)

    2014-10-31

    University focused on exploring the consequences of high percentage rare earth substitution (>25%) effects on the high-Tc superconducting state of this... Superconductivity in layered lanthanide oxygen bismuth sulfide compounds Measurements of (T) between 1 K and 300 K at various pressures up to ~3 GPa...grant. Many new superconductors were discovered, most with transition temperatures (Tc) below 10K. One noteworthy discovery was the superconductivity

  7. Quantum Magnetic Excitations from Stripes in Copper-Oxide Superconductors

    OpenAIRE

    Tranquada, J. M.; Woo, H.; Perring, T. G.; Goka, H; Gu, G. D.; Xu, G; Fujita, M.; Yamada, K.

    2004-01-01

    In the copper-oxide parent compounds of the high-transition-temperature superconductors, the valence electrons are localized, one per copper site, due to strong intraatomic Coulomb repulsion. A symptom of the localization is antiferromagnetism, where the spins of localized electrons alternate between up and down. The superconductivity appears when mobile 'holes' are doped into this insulating state, and it coexists with antiferromagnetic fluctuations. In one approach to the coexistence, the h...

  8. An overview of the Fe-chalcogenide superconductors

    Science.gov (United States)

    Wu, M. K.; Wu, P. M.; Wen, Y. C.; Wang, M. J.; Lin, P. H.; Lee, W. C.; Chen, T. K.; Chang, C. C.

    2015-08-01

    This review intends to summarize recent advancements in FeSe and related systems. The FeSe and related superconductors are currently receiving considerable attention for the high critical temperature (T C) observed and for many similar features to the high T C cuprate superconductors. These similarities suggest that understanding the FeSe-based compounds could potentially help our understanding of the cuprates. We begin the review by presenting common features observed in the FeSe- and FeAs-based systems. Then we discuss the importance of careful control of the material preparation allowing for a systematic structure characterization. With this control, numerous rich phases have been observed. Importantly, we suggest that the Fe-vacancy ordered phases found in the FeSe-based compounds, which are non-superconducting magnetic Mott insulators, are the parent compounds of the superconductors. Superconductivity can emerge from the parent phases by disordering the Fe vacancy order, often by a simple annealing treatment. Then we review physical properties of the Fe chalcogenides, specifically the optical properties and angle-resolved photoemission spectroscopy (ARPES) results. From the literature, strong evidence points to the existence of orbital modification accompanied by a gap-opening, prior to the structural phase transition, which is closely related to the occurrence of superconductivity. Furthermore, strong lattice to spin coupling are important for the occurrence of superconductivity in FeSe. Therefore, it is believed that the iron selenides and related compounds will provide essential information to understand the origin of superconductivity in the iron-based superconductors, and possibly the superconducting cuprates.

  9. Electrical resistivity and XRD measurements on YBCO-PbS HTS system

    Energy Technology Data Exchange (ETDEWEB)

    Tyagi, A.K. (Dept. of Applied Physics, GND Univ., Amritsar (India)); Shahi, K. (Advanced Centre for Materials Science, IIT Kanpur (India))

    1992-08-16

    Electrical resistivity and XRD measurements are reported for HTS samples with starting composition Y[sub 1]Ba[sub 2](Cu[sub 1] [sub -] [sub x]Pb[sub x])[sub 3]S[sub 3x]O[sub y](0 [<=] x [<=] 0.20). It is elucidated that the substituted compounds (0 < x [<=] 0.05) have improved processibility and normal state properties (e.g., better intergrain linkage) and a peculiar characteristic trend of variation in superconducting properties like transition temperature (T[sub c]) and transition width ([Delta]T[sub c]), at the cost of lowering T[sub c] by hardly a few K. For x > 0.05 samples, however, the evolution of impurity phases like Y[sub 2]Ba[sub 1]Cu[sub 1]O[sub 5] and BaPbO[sub 3] suppresses the superconducting properties. The probable explanation of these results is also discussed. It is found that perhaps the sulphur of PbS substitutes for oxygen in the YBCO-lattice, however, Pb does not, it mainly forms the impurity phase BaPbO[sub 3].

  10. Process for fabricating continuous lengths of superconductor

    Science.gov (United States)

    Kroeger, Donald M.; List, III, Frederick A.

    1998-01-01

    A process for manufacturing a superconductor. The process is accomplished by depositing a superconductor precursor powder on a continuous length of a first substrate ribbon, overlaying a continuous length of a second substrate ribbon on said first substrate ribbon, and applying sufficient pressure to form a bound layered superconductor precursor between said first substrate ribbon and said second substrates ribbon. The layered superconductor precursor is then heat treated to form a super conductor layer.

  11. Ferromagnet / superconductor oxide superlattices

    Science.gov (United States)

    Santamaria, Jacobo

    2006-03-01

    The growth of heterostructures combining oxide materials is a new strategy to design novel artificial multifunctional materials with interesting behaviors ruled by the interface. With the (re)discovery of colossal magnetoresistance (CMR) materials, there has been renewed interest in heterostructures involving oxide superconductors and CMR ferromagnets where ferromagnetism (F) and superconductivity (S) compete within nanometric distances from the interface. In F/S/F structures involving oxides, interfaces are especially complex and various factors like interface disorder and roughness, epitaxial strain, polarity mismatch etc., are responsible for depressed magnetic and superconducting properties at the interface over nanometer length scales. In this talk I will focus in F/S/F structures made of YBa2Cu3O7 (YBCO) and La0.7Ca0.3MnO3 (LCMO). The high degree of spin polarization of the LCMO conduction band, together with the d-wave superconductivity of the YBCO make this F/S system an adequate candidate for the search of novel spin dependent effects in transport. We show that superconductivity at the interface is depressed by various factors like charge transfer, spin injection or ferromagnetic superconducting proximity effect. I will present experiments to examine the characteristic distances of the various mechanisms of superconductivity depression. In particular, I will discuss that the critical temperature of the superconductor depends on the relative orientation of the magnetization of the F layers, giving rise to a new giant magnetoresistance effect which might be of interest for spintronic applications. Work done in collaboration with V. Peña^1, Z. Sefrioui^1, J. Garcia-Barriocanal^1, C. Visani^1, D. Arias^1, C. Leon^1 , N. Nemes^2, M. Garcia Hernandez^2, S. G. E. te Velthuis^3, A. Hoffmann^3, M. Varela^4, S. J. Pennycook^4. Work supported by MCYT MAT 2005-06024, CAM GR- MAT-0771/2004, UCM PR3/04-12399 Work at Argonne supported by the Department of Energy, Basic

  12. Transient analysis of an HTS DC power cable with an HVDC system

    Science.gov (United States)

    Dinh, Minh-Chau; Ju, Chang-Hyeon; Kim, Jin-Geun; Park, Minwon; Yu, In-Keun; Yang, Byeongmo

    2013-11-01

    The operational characteristics of a superconducting DC power cable connected to a highvoltage direct current (HVDC) system are mainly concerned with the HVDC control and protection system. To confirm how the cable operates with the HVDC system, verifications using simulation tools are needed. This paper presents a transient analysis of a high temperature superconducting (HTS) DC power cable in connection with an HVDC system. The study was conducted via the simulation of the HVDC system and a developed model of the HTS DC power cable using a real time digital simulator (RTDS). The simulation was performed with some cases of short circuits that may have caused system damage. The simulation results show that during the faults, the quench did not happen with the HTS DC power cable because the HVDC controller reduced some degree of the fault current. These results could provide useful data for the protection design of a practical HVDC and HTS DC power cable system.

  13. HTS 63_4_ GROENEWALD.A.Barth and politics _geredigeer

    African Journals Online (AJOL)

    p1243322

    Karl Barth's role in church and politics from 1930 to 1935. 1614. HTS 63(4) 2007 .... Thinking means post- contemplation, cogitare arises from cogere ..... coincide with a specific moment of Christian and German truth. He sets his own.

  14. R&D on Resistive Heat Exchangers for HTS High Rated Current Leads%R&D on Resistive Heat Exchangers for HTS High Rated Current Leads

    Institute of Scientific and Technical Information of China (English)

    毕延芳

    2011-01-01

    The HTS current leads of superconducting magnets for large scale fusion devices and high energy particle colliders can reduce the power consumption for cooling by 2/3 compared with conventional leads. The resistive sections of high-rated current leads are usually made of a heat exchanger cooled by gas flow. The supply of the cooling mass flow incurs more than 90% of the cooling cost for the HTS leads. The mass flow rate requirement depends not only on the length and material of the resistive heat exchanger, but also on the heat transfer coefficient and HEX surface, the joint resistance at the cold end of a sheet-stack HEX with a larger specific presented in the paper. The test results of efficiency can be achieved. and its cooling approach. The design and operation surface and a much smaller hydraulic diameter are an HTS lead optimized for 8 kA show that a 98.4%

  15. Gravitoelectromagnetism and Dark Energy in Superconductors

    CERN Document Server

    De Matos, C J

    2006-01-01

    A gravitomagnetic analogue of the London moment in superconductors can explain the anomalous Cooper pair mass excess reported by Janet Tate. Ultimately the gravitomagnetic London moment is attributed to the breaking of the principle of general covariance in superconductors. This naturally implies non-conservation of classical energy-momentum. Possible relation with the manifestation of dark energy in superconductors is questioned.

  16. Design of the HTS Fusion Conductors for TF and CS Coils

    OpenAIRE

    Bykovsky, Nikolay; Uglietti, Davide; Wesche, Rainer; Bruzzone, Pierluigi

    2016-01-01

    The main electrical and mechanical requirements for the LTS fusion conductors of DEMO are retained as a starting point for the development of HTS fusion cables. Based on the HTS coated conductor technology, a flat cable design was proposed by CRPP Swiss Plasma Center (SPC) using the strands made of twisted stack of tapes soldered into copper profiles. Analytical modeling of the cable geometry is developed and presented in this work. The model was used to estimate various properties of cable. ...

  17. prototype Roebel cable to be used to wind a HTS accelerator demonstration dipole

    CERN Multimedia

    Barnard, Henry

    2014-01-01

    This is a prototype Roebel cable to be used to wind a HTS accelerator demonstration dipole, a first of its kind, within the scope of EuCARD2 WP10 (Future Magnets). The strips are stainless steel and copper, but the final one will be an HTS tape (YBCO) and copper. This prototype cable was manufactured by KIT within the scope of EuCARD2.

  18. Cryogenic Cooling System for 5 kA, 200 μH Class HTS DC Reactor

    Science.gov (United States)

    Park, Heecheol; Kim, Seokho; Kim, Kwangmin; Park, Minwon; Park, Taejun; Kim, A.-rong; Lee, Sangjin

    DC reactors, made by aluminum busbar, are used to stabilize the arc of an electric furnace. In the conventional arc furnace, the transport current is several tens of kilo-amperes and enormous resistive loss is generated. To reduce the resistive loss at the DC reactor, a HTS DC reactor can be considered. It can dramatically improve the electric efficiency as well as reduce the installation space. Similar with other superconducting devices, the HTS DC reactor requires current leads from a power source in room temperature to the HTS coil in cryogenic environment. The heat loss at the metal current leads can be minimized through optimization process considering the geometry and the transport current. However, the transport current of the HTS DC reactor for the arc furnace is much larger than most of HTS magnets and the enormous heat penetration through the current lead should be effectively removed to keep the temperature around 70∼77 K. Current leads are cooled down by circulation of liquid nitrogen from the cooling system with a stirling cryocooler. The operating temperature of HTS coil is 30∼40 K and circulation of gaseous helium is used to remove the heat generation at the HTS coil. Gaseous helium is transported through the cryogenic helium blower and a single stage GM cryocooler. This paper describes design and experimental results on the cooling system for current leads and the HTS coil of 5 kA, 200 μH class DC reactor as a prototype. The results are used to verify the design values of the cooling systems and it will be applied to the design of scale-up cooling system for 50 kA, 200 μH class DC reactor.

  19. Renormalization effects and phonon density of states in high temperature superconductors

    Directory of Open Access Journals (Sweden)

    Vinod Ashokan

    2013-02-01

    Full Text Available Using the versatile double time thermodynamic Green's function approach based on many body theory the renormalized frequencies, phonon energy line widths, shifts and phonon density of states (PDOS are investigated via a newly formulated Hamiltonian (does not include BCS type Hamiltonian that includes the effects of electron-phonon, anharmonicities and that of isotopic impurities. The automatic appearance of pairons, temperature, impurity and electron-phonon coupling of renormalized frequencies, widths, shifts and PDOS emerges as a characteristic feature of present theory. The numerical investigations on PDOS for the YBa2Cu3O7 − δ crystal predicts several new feature of high temperature superconductors (HTS and agreements with experimental observations.

  20. Published assessments bearing on the future use of ceramic superconductors by the electric power sector

    Energy Technology Data Exchange (ETDEWEB)

    Giese, R.F.; Wolsky, A.M.

    1992-08-25

    Much has been written about ceramic superconductors since their discovery in 1986. Most of this writing reports and describes scientific research. However, some authors have sought to put this research in context: to assess where the field stands, what might be technically feasible, what might be economically feasible, and what potential impacts ceramic superconductors will bring to the electric power sector. This report's purpose is to make the results of already published assessments readily available. To that end, this report lists and provides abstracts for various technical and economic assessments related to applications of High-Temperature Superconductors (HTS) to the electric power sector. Those studies deemed most important are identified and summarized. These assessments were identified by two means. First, members of the Executive Committee identified some reports as worthy of consideration and forwarded them to Argonne National Laboratory. Twelve assessments were selected. Each of these is listed and summarized in the following section. Second, a bibliographic search was performed on five databases: INSPEC, NTIS, COMPENDEX, Energy Science Technology, and Electric Power Database. The search consisted of first selecting all papers related to High Temperature Superconductors. Then papers related to SMES, cables, generators, motors, fault current limiters, or electric utilities were selected. When suitable variants of the above terms were included, this resulted in a selection of 493 citations. These citations were subjected to review by the authors. A number of citations were determined to be inappropriate (e.g. a number referred to digital transmission lines for electronics and communications applications). The reduced list consisted of 200 entries. Each of these citations, with an abstract, is presented in the following sections.

  1. Published assessments bearing on the future use of ceramic superconductors by the electric power sector

    Energy Technology Data Exchange (ETDEWEB)

    Giese, R.F.; Wolsky, A.M.

    1992-08-25

    Much has been written about ceramic superconductors since their discovery in 1986. Most of this writing reports and describes scientific research. However, some authors have sought to put this research in context: to assess where the field stands, what might be technically feasible, what might be economically feasible, and what potential impacts ceramic superconductors will bring to the electric power sector. This report`s purpose is to make the results of already published assessments readily available. To that end, this report lists and provides abstracts for various technical and economic assessments related to applications of High-Temperature Superconductors (HTS) to the electric power sector. Those studies deemed most important are identified and summarized. These assessments were identified by two means. First, members of the Executive Committee identified some reports as worthy of consideration and forwarded them to Argonne National Laboratory. Twelve assessments were selected. Each of these is listed and summarized in the following section. Second, a bibliographic search was performed on five databases: INSPEC, NTIS, COMPENDEX, Energy Science & Technology, and Electric Power Database. The search consisted of first selecting all papers related to High Temperature Superconductors. Then papers related to SMES, cables, generators, motors, fault current limiters, or electric utilities were selected. When suitable variants of the above terms were included, this resulted in a selection of 493 citations. These citations were subjected to review by the authors. A number of citations were determined to be inappropriate (e.g. a number referred to digital transmission lines for electronics and communications applications). The reduced list consisted of 200 entries. Each of these citations, with an abstract, is presented in the following sections.

  2. Highly oxidized superconductors

    Science.gov (United States)

    Morris, Donald E.

    1994-01-01

    Novel superconducting materials in the form of compounds, structures or phases are formed by performing otherwise known syntheses in a highly oxidizing atmosphere rather than that created by molecular oxygen at atmospheric pressure or below. This leads to the successful synthesis of novel superconducting compounds which are thermodynamically stable at the conditions under which they are formed.

  3. Multistrand superconductor cable

    Science.gov (United States)

    Borden, Albert R.

    1985-01-01

    Improved multistrand Rutherford-type superconductor cable is produced by using strands which are preformed, prior to being wound into the cable, so that each strand has a variable cross section, with successive portions having a substantially round cross section, a transitional oval cross section, a rectangular cross section, a transitional oval cross section, a round cross section and so forth, in repetitive cycles along the length of the strand. The cable is wound and flattened so that the portions of rectangular cross section extend across the two flat sides of the cable at the strand angle. The portions of round cross section are bent at the edges of the flattened cable, so as to extend between the two flat sides. The rectangular portions of the strands slide easily over one another, so as to facilitate flexing and bending of the cable, while also minimizing the possibility of causing damage to the strands by such flexing or bending. Moreover, the improved cable substantially maintains its compactness and cross-sectional shape when the cable is flexed or bent.

  4. Terahertz Detection with Twin Superconductor-Insulator-Superconductor Tunnel Junctions

    Institute of Scientific and Technical Information of China (English)

    LI Jing; WANG Ming-Jye; SHI Sheng-Cai; Hiroshi Mat-suo

    2007-01-01

    Terahertz detection with twin superconductor-insulator-superconductor (SIS) tunnel junctions, which are connected in parallel via an inductive thin-film superconducting microstrip line, is mainly studied. Firstly, we investigate the direct-detection response of a superconducting twin-junction device by means of a Fourier transform spectrometer. Secondly, we construct a direct-detection model of twin SIS tunnel junctions. The superconducting twin-junction device is then simulated in terms of the constructed model. The simulation result is found to be in good agreement with the measured one. In addition, we observe that the direct-detection response of the device is consistent with the noise temperature behaviour.

  5. The surface discharge and breakdown characteristics of HTS DC cable and stop joint box

    Science.gov (United States)

    Kim, W. J.; Kim, H. J.; Cho, J. W.; Kim, S. H.

    2014-09-01

    A high temperature superconducting (HTS) DC cable system consists of a HTS cable and cable joint. The HTS DC cable should be electrically connected in joint boxes because of the unit length of HTS cable is limited to several-hundred meters. In particular, the stop joint box (SJB) must be developed for a compact cooling system. Polypropylene laminated paper (PPLP) and epoxy maybe used as insulating materials for HTS DC cable and SJB. To develop a HTS DC cable, it is necessary to develop the cryogenic insulation technology, materials and the joint methods. In this paper, we will mainly discuss on the DC and impulse characteristics of epoxy and PPLP in liquid nitrogen (LN2). The surface discharge characteristics of epoxy included fillers, PPLP and epoxy with PPLP composite (epoxy + PPLP) were measured under 0.4 MPa. Also, the PPLP-insulated mini-model cable was fabricated and then DC, impulse and DC polarity reversal breakdown strength of mini-model cable under 0.4 MPa were investigated.

  6. Loss measurement and analysis for the prototype generator with HTS stator and permanent magnet rotor

    Energy Technology Data Exchange (ETDEWEB)

    Song, Peng, E-mail: songp10@mails.tsinghua.edu.cn [Applied Superconductivity Research Center, Department of Physics, Tsinghua University, Beijing 100084 (China); Qu, Timing, E-mail: tmqu@mail.tsinghua.edu.cn [Applied Superconductivity Research Center, Department of Physics, Tsinghua University, Beijing 100084 (China); Department of Mechanical Engineering, Tsinghua University, Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Beijing 100084 (China); Yu, Xiaoyu [Department of Mechanical Engineering, Tsinghua University, Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Beijing 100084 (China); Li, Longnian; Gu, Chen [Applied Superconductivity Research Center, Department of Physics, Tsinghua University, Beijing 100084 (China); Li, Xiaohang [Innova Superconductor Technology Co., Ltd., Beijing 100084 (China); Wang, Dewen; Hu, Boping [Beijing Zhong Ke San Huan Hi-Tech Co., Ltd., Beijing 100084 (China); Chen, Duxing [Department Fis, University Autonoma Barcelona, Barcelona 08193 (Spain); Han, Zhenghe [Applied Superconductivity Research Center, Department of Physics, Tsinghua University, Beijing 100084 (China)

    2013-11-15

    Highlights: •A novel prototype HTS generator with HTS armature windings was developed. •No-load loss and the iron loss at low temperature were measured. •The total loss at low temperature is much larger than the room temperature case. •The reason for no-load loss increment at low temperature is discussed. -- Abstract: A prototype HTS synchronous generator with a permanent magnet rotor and HTS armature windings was developed. The rated armature frequency is 10 Hz. The cryogenic Dewar is tightly surrounded outside the iron core. Both HTS coils and the iron core were cooled by using conduction cooling method. During the process of no-load running, the no-load loss power data were obtained through the torque measurement. The temperature evolution characteristics of the stator was measured by PT-100 temperature sensors. These results show that the no-load loss power at around 77 K are much larger than that at room temperature. The possible reason for the no-load loss increment is discussed. The ac loss power of one individual HTS coil used in this generator was also tested. Compared with the iron loss power, the ac loss power is rather small and could be neglected.

  7. Development of (RE)BCO cables for HTS power transmission lines

    Science.gov (United States)

    Mukoyama, S.; Yagi, M.; Masuda, T.; Amemiya, N.; Ishiyama, A.; Kashima, N.; Nagaya, S.; Aoki, Y.; Yoshizumi, M.; Yamada, Y.; Izumi, T.; Shiohara, Y.

    2009-10-01

    High-temperature superconducting (HTS) power cables transmit bulk power with lower loss than conventional cables. Moreover, HTS cables are expected to be constructed as a new underground cable in urban areas at lower cost compared to a high voltage XLPE cable. To put promising HTS cables to practical use, we need (RE)BCO tapes with long length, high critical current, and low cost. Recently many organizations have improved the performance of the (RE)BCO tapes, such as YBCO tapes, or other coated conductor tapes that are made with a variety of different processes. We have fabricated the conductors for the HTS power cable that was constructed of different kinds of (RE)BCO tapes and measured the I c and AC losses. We achieved significantly low AC loss of 0.1 W/m at 1 kA in the HTS conductor using narrow slit tapes that were cut by laser. Moreover, a 20 m long HTS power cable model and a cable intermediate joint were developed. Short circuit current tests were conducted on the cable system that consisted of two 10 m cables, a cable joint, and two terminations. The cables and the joint withstood the short circuit current of 31.5 kA for 2 s without damage.

  8. Development of (RE)BCO cables for HTS power transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Mukoyama, S., E-mail: mukoyama@ch.furukawa.co.j [Furukawa Electric Co. Ltd., Ichihara 290-8555 (Japan); Yagi, M. [Furukawa Electric Co. Ltd., Ichihara 290-8555 (Japan); Masuda, T. [Sumitomo Electric Industries, Ltd., Osaka 554-0024 (Japan); Amemiya, N. [Kyoto University, Kyoto 615-8510 (Japan); Ishiyama, A. [Waseda University, Tokyo 169-8555 (Japan); Kashima, N.; Nagaya, S. [Chubu Electric Power Co. Inc., Nagoya 459-8522 (Japan); Aoki, Y. [Showa Cable System Co. Ltd., Sagamihara 229-1133 (Japan); Yoshizumi, M.; Yamada, Y.; Izumi, T.; Shiohara, Y. [Superconductivity Research Laboratory, Tokyo 135-0062 (Japan)

    2009-10-15

    High-temperature superconducting (HTS) power cables transmit bulk power with lower loss than conventional cables. Moreover, HTS cables are expected to be constructed as a new underground cable in urban areas at lower cost compared to a high voltage XLPE cable. To put promising HTS cables to practical use, we need (RE)BCO tapes with long length, high critical current, and low cost. Recently many organizations have improved the performance of the (RE)BCO tapes, such as YBCO tapes, or other coated conductor tapes that are made with a variety of different processes. We have fabricated the conductors for the HTS power cable that was constructed of different kinds of (RE)BCO tapes and measured the I{sub c} and AC losses. We achieved significantly low AC loss of 0.1 W/m at 1 kA in the HTS conductor using narrow slit tapes that were cut by laser. Moreover, a 20 m long HTS power cable model and a cable intermediate joint were developed. Short circuit current tests were conducted on the cable system that consisted of two 10 m cables, a cable joint, and two terminations. The cables and the joint withstood the short circuit current of 31.5 kA for 2 s without damage.

  9. Topological insulators and topological superconductors

    CERN Document Server

    Bernevig, Andrei B

    2013-01-01

    This graduate-level textbook is the first pedagogical synthesis of the field of topological insulators and superconductors, one of the most exciting areas of research in condensed matter physics. Presenting the latest developments, while providing all the calculations necessary for a self-contained and complete description of the discipline, it is ideal for graduate students and researchers preparing to work in this area, and it will be an essential reference both within and outside the classroom. The book begins with simple concepts such as Berry phases, Dirac fermions, Hall conductance and its link to topology, and the Hofstadter problem of lattice electrons in a magnetic field. It moves on to explain topological phases of matter such as Chern insulators, two- and three-dimensional topological insulators, and Majorana p-wave wires. Additionally, the book covers zero modes on vortices in topological superconductors, time-reversal topological superconductors, and topological responses/field theory and topolo...

  10. Thin film superconductor magnetic bearings

    Science.gov (United States)

    Weinberger, Bernard R.

    1995-12-26

    A superconductor magnetic bearing includes a shaft (10) that is subject to a load (L) and rotatable around an axis of rotation, a magnet (12) mounted to the shaft, and a stator (14) in proximity to the shaft. The stator (14) has a superconductor thin film assembly (16) positioned to interact with the magnet (12) to produce a levitation force on the shaft (10) that supports the load (L). The thin film assembly (16) includes at least two superconductor thin films (18) and at least one substrate (20). Each thin film (18) is positioned on a substrate (20) and all the thin films are positioned such that an applied magnetic field from the magnet (12) passes through all the thin films. A similar bearing in which the thin film assembly (16) is mounted on the shaft (10) and the magnet (12) is part of the stator (14) also can be constructed.

  11. Modified Entropic Gravitation in Superconductors

    CERN Document Server

    de Matos, Clovis Jacinto

    2011-01-01

    Verlinde recently developed a theoretical account of gravitation in terms of an entropic force. The central element in Verlinde's derivation is information and its relation with entropy through the holographic principle. The application of this approach to the case of superconductors requires to take into account that information associated with superconductor's quantum vacuum energy is not stored on Planck size surface elements, but in four volume cells with Planck-Einstein size. This has profound consequences on the type of gravitational force generated by the quantum vacuum condensate in superconductors, which is closely related with the cosmological repulsive acceleration responsible for the accelerated expansion of the Universe. Remarkably this new gravitational type force depends on the level of breaking of the weak equivalence principle for cooper pairs in a given superconducting material, which was previously derived by the author starting from similar principles. It is also shown that this new gravit...

  12. Superconductor stability, 1983: a review

    Energy Technology Data Exchange (ETDEWEB)

    Dresner, L.

    1983-01-01

    Three main topics have been discussed in this paper, namely, internally cooled superconductors, cooling by superfluid helium, and metastable magnets. The discussion of each has centered around a dominant idea, and it is fitting to highlight these ideas by way of conclusion. With regard to internally cooled superconductors, most of what we have learned in the last few years centers on the strong motion caused by the thermal expansion of helium. How naive were our early calculations that treated the helium as though it were incompressible. Our discussion of He-II was organized around the Gorter-Mellink relation and the solutions of the nonlinear diffusion equation it gives rise to. And our discussion of metastable magnets revolved around the fruitful concept of the MPZ. These three ideas are sturdy trunks that support much of the thought about superconductor stability that has flowered in the past several years.

  13. Nanoengineering of Flux Pinning Sites in High-Tc Superconductors

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Volume pinning forces were determined for a variety of bulk high-Tcsuperconductors of the 123-type from magnetization measurements. By means of scaling of the pinning forces, the acting pinning mechanisms in various temperature ranges were identified. The Nd-based superconductors and some YBCO crystalsexhibited a dominating pinning of the δTc-type (i.e., small, superconducting pinning sites). In contrast to this, the addition of insulating 211 particles provided pinning of the δl-type; providing effective pinning in the entire temperature range acting as a "background" pinning mechanism for the peak effect. Due to the small coherence lengths of the high-Tc compounds, effective pinning sites are defects or particles of nanometer size relative to ξ3. Integral magnetic measurements of the magnetization as a function of temperature in large applied magnetic fields (up to 7 T) revealed that practically all high-Tc compounds were spatially inhomogeneous, which could be caused byoxygen deficiency (YBCO), solid solutions of Nd/Ba (NdBCO and other light rare earth compounds), intergrowths (Bi-based superconductors), and doping by pair-breaking dopants like Zn, Pr. This implies that the superconducting sample consists of stronger and weaker superconducting areas, coupled together. In large appliedfields, this coupling gets broken and the magnetization versus temperature curves revealed more than one superconducting transition. In contrast, irradiation experiments by neutrons, protons, and heavy-ions enabled the artificial introduction of very effective pinning sites into the high-Tc superconductors, thus creating a large variety of different observations using magnetic data. From all these observations, we construct a pinning diagram for bulk high-Tc superconductors explaining many features observed in high-Tc samples.

  14. Topological surface states in nodal superconductors.

    Science.gov (United States)

    Schnyder, Andreas P; Brydon, Philip M R

    2015-06-24

    Topological superconductors have become a subject of intense research due to their potential use for technical applications in device fabrication and quantum information. Besides fully gapped superconductors, unconventional superconductors with point or line nodes in their order parameter can also exhibit nontrivial topological characteristics. This article reviews recent progress in the theoretical understanding of nodal topological superconductors, with a focus on Weyl and noncentrosymmetric superconductors and their protected surface states. Using selected examples, we review the bulk topological properties of these systems, study different types of topological surface states, and examine their unusual properties. Furthermore, we survey some candidate materials for topological superconductivity and discuss different experimental signatures of topological surface states.

  15. Apparatus for fabricating continuous lengths of superconductor

    Science.gov (United States)

    Kroeger, Donald M.; List, III, Frederick A.

    2002-01-01

    A process and apparatus for manufacturing a superconductor. The process is accomplished by depositing a superconductor precursor powder on a continuous length of a first substrate ribbon, overlaying a continuous length of a second substrate ribbon on said first substrate ribbon, and applying sufficient pressure to form a bound layered superconductor comprising a layer of said superconducting precursor powder between said first substrate ribbon and said second substrates ribbon. The layered superconductor is then heat treated to establish the superconducting phase of said superconductor precursor powder.

  16. 高温超导直线感应电机的电磁优化设计%Electromagnetic optimization design of a HTS linear induction motor

    Institute of Scientific and Technical Information of China (English)

    赵佳; 张威; 方进; 杨中平; 郑琼林; 刘友梅

    2011-01-01

    主要给出了高温超导直线感应电机的设计和电磁分析方法.根据常规直线感应电机设计公式,结合遗传算法和约束条件得到了当前条件下最优化的电机参数.由于高温超导直线感应电机的特殊性,很难用公式法直接得到准确的电机优化参数,因此用有限元电磁分析软件Ansoft对得到的电机模型进行了性能分析,并根据分析结果修改电机参数,直到电机性能满足设计要求为止.%This paper presents the design and the electromagnetic analysis of a high-temperature superconductor (HTS) linear induction motor (LIM). According to the formulas of the normal LIM, combined with genetic algorithm and the constraints, the optimal motor parameters could be obtained. Due to the particularity of the HTS LIM, it's difficult to obtain the accurate motor optimization parameters using the formula method directly. So the model of the motor is made and analyzed using the finite element electromagnetic analysis software Ansoft. According to the results the parameters of the motor will be modified until the characteristics meet the design requirements.

  17. Low-temperature rapid synthesis and superconductivity of Fe-based oxypnictide superconductors.

    Science.gov (United States)

    Fang, Ai-Hua; Huang, Fu-Qiang; Xie, Xiao-Ming; Jiang, Mian-Heng

    2010-03-17

    Fe-based oxypnictide superconductors were successfully synthesized at lower reaction temperatures and with shorter reaction times made possible by starting with less stable compounds, which provide a larger driving force for reactions. Using ball-milled powders of intermediate compounds, phase-pure superconductors with T(c) above 50 K were synthesized at 1173 K in 20 min. This method is particularly advantageous for retaining F, a volatile dopant that enhances superconductivity. Bulk superconductivity and high upper critical fields up to 392 T in Sm(0.85)Nd(0.15)FeAsO(0.85)F(0.15) were demonstrated.

  18. Holographic Multi-Band Superconductor

    CERN Document Server

    Huang, Ching-Yu; Maity, Debaprasad

    2011-01-01

    We propose a gravity dual for the holographic superconductor with multi-band carriers. Moreover, the currents of these carriers are unified under a global non-Abelian symmetry, which is dual to the bulk non-Abelian gauge symmetry. We study the phase diagram of our model, and find it qualitatively agrees with the one for the realistic 2-band superconductor, such as MgB2. We also evaluate the holographic conductivities and find the expected mean-field like behaviors in some cases. However, for a wide range of the parameter space, we also find the non-mean-field like behavior with negative conductivities.

  19. High temperature superconductor current leads

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R. (Hinsdale, IL); Poeppel, Roger B. (Glen Ellyn, IL)

    1995-01-01

    An electrical lead having one end for connection to an apparatus in a cryogenic environment and the other end for connection to an apparatus outside the cryogenic environment. The electrical lead includes a high temperature superconductor wire and an electrically conductive material distributed therein, where the conductive material is present at the one end of the lead at a concentration in the range of from 0 to about 3% by volume, and at the other end of the lead at a concentration of less than about 20% by volume. Various embodiments are shown for groups of high temperature superconductor wires and sheaths.

  20. Terahertz Spectroscopy of Novel Superconductors

    Directory of Open Access Journals (Sweden)

    Stefano Lupi

    2011-01-01

    Full Text Available Through the coupling of Synchrotron Radiation and Michelson interferometry, one may obtain in the terahertz (THz range transmittance and reflectivity spectra with a signal-to-noise ratio (S/N up to 103. In this paper we review the application of this spectroscopic technique to novel superconductors with an increasing degree of complexity: the single-gap boron-doped diamond; the isotropic multiband V3Si, where superconductivity opens two gaps at the Fermi energy; the CaAlSi superconductor, isostructural to MgB2, with a single gap in the hexagonal ab plane and two gaps along the orthogonal c axis.

  1. Topological Aspects of Triplet Superconductors

    Institute of Scientific and Technical Information of China (English)

    REN Ji-Rong; XU Dong-Hui; ZHANG Xin-Hui; LI Ran

    2007-01-01

    In this paper, using the φ-mapping theory, it is shown that two kinds of topological defects, i.e., the vortex lines and the monopoles exist in the helical configuration of magnetic field in triplet superconductors. And the inner topological structure of these defects is studied. Because the knot solitons in the triplet superconductors are characterized by the Hopf invariant, we also establish a relationship between the Hopf invariant and the linking number of knots family,and reveal the inner topological structure of the Hopf invariant.

  2. Holographic superconductors without translational symmetry

    CERN Document Server

    Zeng, Hua Bi

    2014-01-01

    A holographic superconductor is constructed in the background of a massive gravity theory. In the normal state without condensation, the conductivity exhibits a Drude peak that approaches a delta function in the massless gravity limit as studied by David Vegh. In the superconducting state, besides the infinite DC conductivity, the AC conductivity has Drude behavior at low frequency followed by a power law-fall. These results are in agreement with that found earlier by Horowitz and Santos, who studied a holographic superconductor with an implicit periodic potential beyond the probe limit. The results also agree with measurements on some cuprates.

  3. Raman spectroscopy of manganite (CMR) and cuprate (HTS) oxides

    CERN Document Server

    Malde, N

    2002-01-01

    This thesis discusses Raman scattering measurements on colossal magnetoresistive (CMR) manganite and high temperature superconducting (HTS) cuprate oxides. We have examined the influence of oxygen partial pressure (PO sub 2) on the Raman active phonon modes in infinite layer (n = infinity) manganite thin films. The 230cm sup - sup 1 and 600cm sup - sup 1 phonon frequencies were found to monotonically harden as function of PO sub 2 , therefore serving as good indicators of oxygen stoichiometry. Temperature dependent Raman scattering measurements on two La sub 0 sub . sub 7 Ca sub 0 sub . sub 3 MnO sub 3 (n = infinity) thin films with different structural distortions (induced by deoxygenation) revealed that the 480cm sup - sup 1 and 610cm sup - sup 1 phonon peak intensities were correlated with the d.c resistivity in both films. This could help clarify the role played by phonons on carrier localisation (for T>T sub c) that has been suggested to explain the CMR effect. The controversial origin of the 'FM-like' o...

  4. Alternative Design Concepts for Multi-Circuit HTS Link Systems

    CERN Document Server

    Ballarino, A

    2011-01-01

    Superconducting cables for power transmission usually contain two conductors for DC application, or three conductors for AC, with high voltage insulation. In contrast, for some applications related to accelerators it is convenient to transfer high currents via superconducting links feeding a number of circuits at relatively low voltage, of the order of a kilovolt, over distances of up to a few hundred meters. For power transmission applications based on cooling via sub-cooled liquid nitrogen, suitable HTS conductors are only available in the form of tape, and a multi-layer variant can be envisaged for the multi-circuit links. However, where cooling to temperatures of the order of 20 K is feasible, MgB2 conductor, available in the form of both tape and wire, can also be envisaged and in the latter case used to assemble round cables. There are, therefore, two distinct topologies - based on the use of wires or tapes - that can be envisaged for use in applications to multi-circuit link systems. In this paper the ...

  5. Heat Transfer Study for HTS Power Transfer Cables

    Science.gov (United States)

    Augustynowicz, S.; Fesmire, J.

    2002-01-01

    Thermal losses are a key factor in the successful application of high temperature superconducting (HTS) power cables. Existing concepts and prototypes rely on the use of multilayer insulation (MLI) systems that are subject to large variations in actual performance. The small space available for the thermal insulation materials makes the application even more difficult because of bending considerations, mechanical loading, and the arrangement between the inner and outer piping. Each of these mechanical variables affects the heat leak rate. These factors of bending and spacing are examined in this study. Furthermore, a maintenance-free insulation system (high vacuum level for 20 years or longer) is a practical requirement. A thermal insulation system simulating a section of a flexible FITS power cable was constructed for test and evaluation on a research cryostat. This paper gives experimental data for the comparison of ideal MLI, MLI on rigid piping, and MLI between flexible piping. A section of insulated flexible piping was tested under cryogenic vacuum conditions including simulated bending and spacers.

  6. Large Coaxial Coldfinger Ptc for Process Liquefaction and Hts Applications

    Science.gov (United States)

    Spoor, P. S.; Corey, J. A.

    2010-04-01

    Large (>100 W cooling capacity at 80 K) `pulse-tube' coolers are ideal candidates for emerging applications such as HTS transmission lines, transformers, and motor windings, meso-scale oxygen liquefaction on-demand, cryopumping, and cryogen boiloff recovery. A number of successful large `in-line' pulse-tube coolers have been built, but these require embedded shell-and-tube process heat exchangers, hence transport of the process fluid/gas to and from the coldhead, and often a high degree of process fluid purity, to avoid clogging in the narrow inlets and outlets of these heat exchangers. It is far preferable in most circumstances to have a coldfinger design that presents a salient cold tip, with the coldhead at the end of a flexible transfer line, as is done with Gifford-McMahon or Joule-Thomson coolers. This paper presents some design details and data from the development of our first high-capacity coldfinger, as well as the results of its application to a 55 gallon/day oxygen liquefier for the Navy.

  7. Triaxial HTS Cable for the AEP Bixby Project

    Energy Technology Data Exchange (ETDEWEB)

    Demko, Jonathan A [ORNL; Gouge, Michael J [ORNL; Lindsay, David T [ORNL; Roden, Mark L [ORNL; Tolbert, Jerry Carlton [ORNL

    2007-01-01

    Ultera has installed a single 200-meter long high temperature superconducting (HTS) 3-phase triaxial design cable at the American Electric Power (AEP) Bixby substation in Columbus, Ohio. The cable connects a 132/13.8 kV transformer to the distribution switchgear serving seven outgoing circuits. It was designed to carry 3000 Arms. Testing of 3- to 5-meter length prototype cables, including a 5-meter prototype with full scale terminations tested at ORNL was conducted prior to the manufacture and installation of the AEP triaxial cable. These prototypes were used to demonstrate the crucial operating conditions including steady state operation at the 3000 Arms design current, high voltage operation, high voltage withstand and 110 kV impulse, and overcurrent fault capability. A summary of the results from the thermal analysis and testing conducted by Ultera and ORNL will be presented. Some analysis of the cable thermal-hydraulic response based on the testing that were used to determine some of the cable cryogenic system requirements are also presented.

  8. Neon turbo-Brayton cycle refrigerator for HTS power machines

    Science.gov (United States)

    Hirai, Hirokazu; Hirokawa, M.; Yoshida, Shigeru; Nara, N.; Ozaki, S.; Hayashi, H.; Okamoto, H.; Shiohara, Y.

    2012-06-01

    We developed a prototype turbo-Brayton refrigerator whose working fluid is neon gas. The refrigerator is designed for a HTS (High Temperature Superconducting) power transformer and its cooling power is more than 2 kW at 65 K. The refrigerator has a turboexpander and a turbo-compressor, which utilize magnetic bearings. These rotational machines have no rubbing parts and no oil-components. Those make a long maintenance interval of the refrigerator. The refrigerator is very compact because our newly developed turbo-compressor is volumetrically smaller than a displacement type compressor in same operating specification. Another feature of the refrigerator is a wide range operation capability for various heat-loads. Cooling power is controlled by the input-power of the turbo-compressor instead of the conventional method of using an electric heater. The rotational speed of the compressor motor is adjusted by an inverter. This system is expected to be more efficient. We show design details, specification and cooling test results of the new refrigerator in this paper.

  9. Ceramic high temperature superconductors for high current applications

    Energy Technology Data Exchange (ETDEWEB)

    Christiansen, J.

    1996-12-31

    Composite Reaction Texturing (CRT) is a technique which uses a fine distribution of pre-aligned seeds as nucleating sites for texturing oxide superconductors. It has successfully been applied to the texturing of Bi-2212 compounds. A furhter application of CRT is reported in which Y-123 is biaxially textured using seeds of other Rare Earth-123 compounds with higher melting points as nucleating sites. The resultant textured microstructure exhibits mainly low angle grain boundaries (up to 5 deg. misorientation). Results will be presented on the seed alignment techniques, the development of microstructure during reaction of the composite preform and preliminary measurements of electromagnetic properties. (au). 111 refs.

  10. HTS Nested magnet wound with 12 mm GdBCO tape and 4.4 mm YBCO tape

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Myung Hun; Ku, Myung Hwan; Cha, Guee Soo [Soonchunhyang University, Asan (Korea, Republic of); Lim, Hyoung Woo [Iljin Electric. Co. LTD, Hwaseong (Korea, Republic of)

    2015-06-15

    The properties of High Temperature Superconducting (HTS) tapes are progressing, as HTS tapes evolve from 1st generation to 2nd generation. This paper presents design and construction of a 2nd generation HTS magnet consisting of two nested GdBCO and YBCO pancake coils. Two HTS tapes of different widths were used to wind the HTS nested magnet. Considering that a higher magnetic field is applied to the inner magnet than to the outer magnet, 12 mm GdBCO tape was used for winding the inner magnet, which consisted of four single pancake windings. Eight double pancake windings wound with 4.4 mm YBCO tapes were used for the outer magnet. The test results show that the central magnetic field of the HTS nested magnet was 920 mT. The measured critical currents of the inner and outer magnet at 77K were 80.8 A and 32.6 A, respectively.

  11. Nature of the superconductor-insulator transition in disordered superconductors.

    Science.gov (United States)

    Dubi, Yonatan; Meir, Yigal; Avishai, Yshai

    2007-10-18

    The interplay of superconductivity and disorder has intrigued scientists for several decades. Disorder is expected to enhance the electrical resistance of a system, whereas superconductivity is associated with a zero-resistance state. Although superconductivity has been predicted to persist even in the presence of disorder, experiments performed on thin films have demonstrated a transition from a superconducting to an insulating state with increasing disorder or magnetic field. The nature of this transition is still under debate, and the subject has become even more relevant with the realization that high-transition-temperature (high-T(c)) superconductors are intrinsically disordered. Here we present numerical simulations of the superconductor-insulator transition in two-dimensional disordered superconductors, starting from a microscopic description that includes thermal phase fluctuations. We demonstrate explicitly that disorder leads to the formation of islands where the superconducting order is high. For weak disorder, or high electron density, increasing the magnetic field results in the eventual vanishing of the amplitude of the superconducting order parameter, thereby forming an insulating state. On the other hand, at lower electron densities or higher disorder, increasing the magnetic field suppresses the correlations between the phases of the superconducting order parameter in different islands, giving rise to a different type of superconductor-insulator transition. One of the important predictions of this work is that in the regime of high disorder, there are still superconducting islands in the sample, even on the insulating side of the transition. This result, which is consistent with experiments, explains the recently observed huge magneto-resistance peak in disordered thin films and may be relevant to the observation of 'the pseudogap phenomenon' in underdoped high-T(c) superconductors.

  12. Test results from Siemens low-speed, high-torque HTS machine and description of further steps towards commercialisation of HTS machines

    Science.gov (United States)

    Nick, Wolfgang; Grundmann, Joern; Frauenhofer, Joachim

    2012-11-01

    With extensive testing of the 4 MW 120 rpm HTS machine connected to a standard Siemens converter this first development stage for a basically new technology is concluded. The most innovative part of the machine, the HTS excited rotor, outperformed our expectations and demonstrated our capability to design, develop and build successfully such a technically challenging component. This could only be achieved on the base of a thorough understanding of the innovative material and its behaviour including practical handling experience, the ability to simulate 3D electromagnetics including transients, and finally transfer of the scientists' knowledge to a qualified manufacturing process. Equally important are the improved capabilities of critical component suppliers, e.g. for superconducting tapes and compact cryo-refrigerators. However, the transition of a technology into highly reliable industrial products does require more than technical mastering of the machine. Based on outstanding technical test results as presented above, the next step in future can be addressed: product development. Some thoughts will be presented regarding the needs of application fields and market oriented development, as the market is not "waiting for HTS". If HTS technology is seen as one key technology for a sustainable, material saving and energy efficient future, it certainly needs more effort, even at the 100th anniversary of superconductivity.

  13. Antiferromagnetic phase diagram of the cuprate superconductors

    Science.gov (United States)

    Nunes, L. H. C. M.; Teixeira, A. W.; Marino, E. C.

    2017-02-01

    Taking the spin-fermion model as the starting point for describing the cuprate superconductors, we obtain an effective nonlinear sigma-field hamiltonian, which takes into account the effect of doping in the system. We obtain an expression for the spin-wave velocity as a function of the chemical potential. For appropriate values of the parameters we determine the antiferromagnetic phase diagram for the YBa2Cu3O6+x compound as a function of the dopant concentration in good agreement with the experimental data. Furthermore, our approach provides a unified description for the phase diagrams of the hole-doped and the electron doped compounds, which is consistent with the remarkable similarity between the phase diagrams of these compounds, since we have obtained the suppression of the antiferromagnetic phase as the modulus of the chemical potential increases. The aforementioned result then follows by considering positive values of the chemical potential related to the addition of holes to the system, while negative values correspond to the addition of electrons.

  14. Analysis of an HTS coil for large scale superconducting magnetic energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ji Young; Lee, Se Yeon; Choi, Kyeong Dal; Park, Sang Ho; Hong, Gye Won; Kim, Sung Soo; Kim, Woo Seok [Korea Polytechnic University, Siheung (Korea, Republic of); Lee, Ji Kwang [Woosuk University, Wanju (Korea, Republic of)

    2015-06-15

    It has been well known that a toroid is the inevitable shape for a high temperature superconducting (HTS) coil as a component of a large scale superconducting magnetic energy storage system (SMES) because it is the best option to minimize a magnetic field intensity applied perpendicularly to the HTS wires. Even though a perfect toroid coil does not have a perpendicular magnetic field, for a practical toroid coil composed of many HTS pancake coils, some type of perpendicular magnetic field cannot be avoided, which is a major cause of degradation of the HTS wires. In order to suggest an optimum design solution for an HTS SMES system, we need an accurate, fast, and effective calculation for the magnetic field, mechanical stresses, and stored energy. As a calculation method for these criteria, a numerical calculation such as an finite element method (FEM) has usually been adopted. However, a 3-dimensional FEM can involve complicated calculation and can be relatively time consuming, which leads to very inefficient iterations for an optimal design process. In this paper, we suggested an intuitive and effective way to determine the maximum magnetic field intensity in the HTS coil by using an analytic and statistical calculation method. We were able to achieve a remarkable reduction of the calculation time by using this method. The calculation results using this method for sample model coils were compared with those obtained by conventional numerical method to verify the accuracy and availability of this proposed method. After the successful substitution of this calculation method for the proposed design program, a similar method of determining the maximum mechanical stress in the HTS coil will also be studied as a future work.

  15. Electrochemical synthesis of alkali-intercalated iron selenide superconductors

    Science.gov (United States)

    Shen, Shi-Jie; Ying, Tian-Ping; Wang, Gang; Jin, Shi-Feng; Zhang, Han; Lin, Zhi-Ping; Chen, Xiao-Long

    2015-11-01

    Electrochemical method has been used to insert K/Na into FeSe lattice to prepare alkali-intercalated iron selenides at room temperature. Magnetization measurement reveals that KxFe2Se2 and NaxFe2Se2 are superconductive at 31 K and 46 K, respectively. This is the first successful report of obtaining metal-intercalated FeSe-based high-temperature superconductors using electrochemical method. It provides an effective route to synthesize metal-intercalated layered compounds for new superconductor exploration. Project supported by the National Natural Science Foundation of China (Grant Nos. 51322211and 91422303), the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No. XDB07020100), Beijing Nova Program of China (Grant No. 2011096), and K. C. Wong Education Foundation, Hong Kong, China.

  16. Muon spin relaxation and Moessbauer studies of iron pnictide superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Klauss, Hans-Henning; Maeter, H.; Dellmann, T. [Technische Universitaet, Dresden (Germany); Luetkens, H.; Khasanov, R.; Amato, A. [PSI, Villigen (Switzerland); Pashkevich, Y. [Donetsk Phystech, NASU (Ukraine); Hess, C.; Klingeler, R.; Buechner, B. [IFW, Dresden (Germany); Leithe-Jasper, A.; Rosner, H.; Geibel, C.; Schnelle, W. [MPI-CPfS, Dresden (Germany); Braden, M. [Universitaet Koeln (Germany); Litterst, J. [Technische Universitaet, Braunschweig (Germany)

    2010-07-01

    We have determined the electronic phase diagrams and order parameters of ReO{sub 1-x}F{sub x}FeAs and (Sr,Eu)Fe{sub 2-x}Co{sub x}As{sub 2} superconductors. The results prove an important role of the structural distortion for the SDW magnetism and reveal two gap multiband superconductivity. We examined the interplay of iron and rare earth magnetic order in ReO{sub 1-x}F{sub x}FeAs. The undoped compounds show different magnetic coupling strength of the rare earth ion to the antiferromagnetic iron layers ranging from independent order to strong polarization of the rare earth moments by the ordered iron. Finally, we present recent studies on (Ca,Sr,Ba,Eu)Fe{sub 2}As{sub 2} and (Fe{sub 2}As{sub 2})(Sr{sub 4}T{sub 2}O{sub 6})based pnictide superconductors.

  17. Nobel Prize winner visits CERN’s superconductors

    CERN Multimedia

    2008-01-01

    On Wednesday 23 April Georg Bednorz, who won the Nobel Prize for physics in 1987, visited CERN along with 44 of his colleagues from the IBM Zurich Research Laboratory. Georg Bednorz (second from right) with colleagues from the IBM Zurich Research Laboratory in the LHC tunnel. On their arrival, Jos Engelen, the Chief Scientific Officer, gave the IBM group an introduction to CERN. Bednorz came to CERN only recently for the Open Days to give a seminar, but unfortunately did not have time to visit the experiments, so this trip was organised instead. Along with Alex Müller, Bednorz was awarded the Noble Prize for his discovery of superconductivity for the so-called high temperature superconductors, essentially copper-oxide-based compounds showing superconductivity at temperatures much higher than had previously been thought possible. The LHC magnets are built with low-temperature superconductors but many current leads that supply power to the LHC cryostats are made with...

  18. Conserved nonlocal dynamics and critical behavior of uranium ferromagnetic superconductors.

    Science.gov (United States)

    Singh, Rohit; Dutta, Kishore; Nandy, Malay K

    2017-01-01

    A recent theoretical study [Phys. Rev. Lett. 112, 037202 (2014)10.1103/PhysRevLett.112.037202] has revealed that systems such as uranium ferromagnetic superconductors obey conserved dynamics. To capture the critical behavior near the paramagnetic to ferromagnetic phase transition of these compounds, we study the conserved critical dynamics of a nonlocal Ginzburg-Landau model. A dynamic renormalization-group calculation at one-loop order yields the critical indices in the leading order of ε=d_{c}-d, where d_{c}=4-2ρ is the upper critical dimension, with ρ an exponent in the nonlocal interaction. The predicted static critical exponents are found to be comparable with the available experimentally observed critical exponents for strongly uniaxial uranium ferromagnetic superconductors. The corresponding dynamic exponent z and linewidth exponent w are found to be z=4-ρε/4+O(ε^{2}) and w=1+ρ+3ε/4+O(ε^{2}).

  19. Conserved nonlocal dynamics and critical behavior of uranium ferromagnetic superconductors

    Science.gov (United States)

    Singh, Rohit; Dutta, Kishore; Nandy, Malay K.

    2017-01-01

    A recent theoretical study [Phys. Rev. Lett. 112, 037202 (2014), 10.1103/PhysRevLett.112.037202] has revealed that systems such as uranium ferromagnetic superconductors obey conserved dynamics. To capture the critical behavior near the paramagnetic to ferromagnetic phase transition of these compounds, we study the conserved critical dynamics of a nonlocal Ginzburg-Landau model. A dynamic renormalization-group calculation at one-loop order yields the critical indices in the leading order of ɛ =dc-d , where dc=4 -2 ρ is the upper critical dimension, with ρ an exponent in the nonlocal interaction. The predicted static critical exponents are found to be comparable with the available experimentally observed critical exponents for strongly uniaxial uranium ferromagnetic superconductors. The corresponding dynamic exponent z and linewidth exponent w are found to be z =4 -ρ ɛ /4 +O (ɛ2) and w =1 +ρ +3 ɛ /4 +O (ɛ2) .

  20. Operational characteristics analysis of a 8 mH class HTS DC reactor for an LCC type HVDC system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. K.; Go, B. S.; Dinh, M. C.; Park, M.; Yu, I. K. [Changwon National University, Changwon (Korea, Republic of); Kim, J. H. [Daejeon University, Daejeon (Korea, Republic of)

    2015-03-15

    Many kinds of high temperature superconducting (HTS) devices are being developed due to its several advantages. In particular, the advantages of HTS devices are maximized under the DC condition. A line commutated converter (LCC) type high voltage direct current (HVDC) transmission system requires large capacity of DC reactors to protect the converters from faults. However, conventional DC reactor made of copper causes a lot of electrical losses. Thus, it is being attempted to apply the HTS DC reactor to an HVDC transmission system. The authors have developed a 8 mH class HTS DC reactor and a model-sized LCC type HVDC system. The HTS DC reactor was operated to analyze its operational characteristics in connection with the HVDC system. The voltage at both ends of the HTS DC reactor was measured to investigate the stability of the reactor. The voltages and currents at the AC and DC side of the system were measured to confirm the influence of the HTS DC reactor on the system. Two 5 mH copper DC reactors were connected to the HVDC system and investigated to compare the operational characteristics. In this paper, the operational characteristics of the HVDC system with the HTS DC reactor according to firing angle are described. The voltage and current characteristics of the system according to the types of DC reactors and harmonic characteristics are analyzed. Through the results, the applicability of an HTS DC reactor in an HVDC system is confirmed.

  1. The Effect of Magnetic Field on HTS Leads What Happens when thePower Fails at RAL?

    Energy Technology Data Exchange (ETDEWEB)

    Green, Michael A.

    2007-02-14

    The key to being able to operate the MICE superconducting solenoids on small coolers is the use of high temperature superconducting (HTS) leads between the first stage of the cooler and the magnet, which operates at around 4.2 K. Because MICE magnets are not shielded, all of the MICE magnets have a stray magnetic field in the region where the coolers and the HTS leads are located. The behavior of the HTS leads in a magnetic field depends strongly on the HTS material used for the leads and the temperature of the cooler first stage temperature. The HTS leads can be specified to operate at the maximum current for the magnet. This report shows how the HTS leads can be specified for use the MICE magnets. MICE magnets take from 1.3 hours (the tracker solenoids) to 3.7 hours (the coupling magnet) to charge to the highest projected operating currents. If the power fails, the cooler and the upper ends of the HTS leads warm up. The question is how one can discharge the magnet to protect the HTS leads without quenching the MICE magnets. This report describes a method that one can use to protect the HTS leads in the event of a power failure at the Rutherford Appleton Laboratory (RAL).

  2. Chemistry of high temperature superconductors

    CERN Document Server

    1991-01-01

    This review volume contains the most up-to-date articles on the chemical aspects of high temperature oxide superconductors. These articles are written by some of the leading scientists in the field and includes a comprehensive list of references. This is an essential volume for researchers working in the fields of ceramics, materials science and chemistry.

  3. Development of superconductor application technology

    Energy Technology Data Exchange (ETDEWEB)

    Hong, G. W.; Kim, C. J.; Lee, H. G.; Lee, H. J.; Kim, K. B.; Won, D. Y.; Jang, K. I.; Kwon, S. C.; Kim, W. J.; Ji, Y. A.; Yang, S. W.; Kim, W. K.; Park, S. D.; Lee, M. H.; Lee, D. M.; Park, H. W.; Yu, J. K.; Lee, I. S.; Kim, J. J.; Choi, H. S.; Chu, Y.; Kim, Y. S.; Kim, D. H.

    1997-09-01

    Fabrication of high Tc bulk superconductor and its application, fabrication of superconducting wire for electric power device and analysis for cryogenic system were carried out for developing superconductor application technologies for electric power system. High quality YBaCuO bulk superconductor was fabricated by controlling initial powder preparation process and prototype flywheel energy storage device was designed basically. The superconducting levitation force measuring device was made to examine the property of prepared superconductor specimen. Systematic studies onthe method of starting powder preparation, mechanical fabrication process, heat treatment condition and analysis of plastic deformation were carried out to increase the stability and reproducibility of superconducting wire. A starting power with good reactivity and fine particle size was obtained by mechanical grinding, control of phase assemblage, and emulsion drying method. Ag/BSCCO tape with good cross sectional shape and Jc of 20,000 A/cm{sup 2} was fabricated by applying CIP packing procedure. Multifilamentary wire with Jc of 10,000 A/cm{sup 2} was fabricated by rolling method using square billet as starting shape. The joining of the multifilamentary wire was done by etching and pressing process and showed 50% of joining efficiency. Analysis on the heat loss in cryostat for high Tc superconducting device was carried out for optimum design of the future cryogenic system. (author). 66 refs., 104 figs.

  4. Practical superconductor development for electrical power applications. Annual report for FY 1992

    Energy Technology Data Exchange (ETDEWEB)

    Goretta, K.C. [comp.

    1992-10-01

    Development of useful high-critical-temperature (high-{Tc}) superconductors requires synthesis of superconducting compounds; fabrication of wires, tapes, and films from these compounds; production of composite structures that incorporate stabilizers or insulators; and design and testing of efficient components. This report describes the technical progress of research and development efforts aimed at producing superconducting components that are based on the Y-Ba-Cu, Bi-Sr-Ca-Cu, Bi-Pb-Sr-Ca-Cu, and (TI,Pb)-(Ba,Sr)-Ca-Cu oxide systems. Topics discussed are synthesis and heat treatment of high-{Tc} superconductors, formation of monolithic and composite wires and tapes, superconductor/metal connectors, characterization of structures and superconducting and mechanical properties, fabrication and properties of thin films, and development of prototype components. Collaborations with industry and academia are documented.

  5. Iron-based superconductors via soft chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Friederichs, Gina Maya

    2015-06-30

    This thesis provides new soft chemistry approaches to Fe-based superconductors. Mild syntheses were demonstrated to be able to overcome difficulties, occurring in conventional synthesis and to enable the access to new metastable phases. A solvent-based metathesis reaction led to β-FeSe exclusively. Contrary to solid state syntheses, the formation of hexagonal α-FeSe could be avoided under mild conditions. The deintercalation of interstitial Fe (by formation of Fe{sub 3}O{sub 4}) could be proven by low temperature O{sub 2}-annealing of Fe{sub 1+x}Te{sub 1-y}Se{sub y}. By using redox (de)intercalations K{sub 1-x}Fe{sub 2-y}Se{sub 2}, metastable Na{sub 1-x}Fe{sub 2-y}As{sub 2} and Na{sub 1-x}((Fe{sub 1-y}Co{sub y}){sub 1-z}As){sub 2} could successfully be obtained at room temperature. The mild synthesis conditions led to compounds like FeSe and K{sub 1-x}Fe{sub 2-y}Se{sub 2} which exhibited different physical properties than found by conventional high temperature methods. In general, the developed (de)intercalation reactions represent a new, universally applicable tool in order to manipulate the structure along with the properties of Fe-based superconductors. The basic structural features of the characteristic FeX{sub 4/4} tetrahedral layers, however, are preserved. Soft chemistry syntheses have been shown to allow the formation of a variety of phases, like Na{sub 1-x}Fe{sub 2-y}As{sub 2}, Na{sub 1-x}((Fe{sub 1-y}Co{sub y}){sub 1-z}As){sub 2} and K{sub 1-x}Fe{sub 2-y}Se{sub 2}. Hence, especially low temperature approaches may enable the realization of complex stacking sequences, potentially leading to the fulfillment of the greatest goal in the research of superconductors - room temperature superconductivity.

  6. Progress of 275 kV-3 kA YBCO HTS cable

    Science.gov (United States)

    Yagi, M.; Mukoyama, S.; Amemiya, N.; Ishiyama, A.; Wang, X.; Aoki, Y.; Saito, T.; Ohkuma, T.; Maruyama, O.

    2011-11-01

    A 275 kV-3 kA high temperature superconducting (HTS) cable has been developed in the Materials & Power Applications of Coated Conductors (M-PACC) project. AC loss reduction of a two-layer HTS conductor was undertaken by removing the edges of YBCO tapes with low critical current density. The HTS conductor using these tapes was fabricated, and low loss of 0.235 W/m at 3 kA rms was achieved. The 275 kV-3 kA cable was designed, and the 2 m model cables were fabricated. This cable had 325 mm 2 copper stranded former inside the HTS conductor and a 310 mm 2 copper shield layer on the HTS shield layer for over-current protection. These cables withstood an over-current of 63.0 kA for 0.6 s, which is the worst situation for 275 kV systems. The partial discharge (PD) and V- t characteristics of a liquid nitrogen (LN 2)/polypropylene (PP) laminated paper composite insulation system have been integrated into the design of the insulation for the 275 kV cable. The results revealed that the PD inception stress (PDIE) did not depend on the insulation thickness, and that lifetime indices of V- t characteristics at PD inception were as high as about 80-100.

  7. Electrical performance analysis of HTS synchronous motor based on 3D FEM

    Science.gov (United States)

    Baik, S. K.; Kwon, Y. K.; Kim, H. M.; Lee, J. D.; Kim, Y. C.; Park, G. S.

    2010-11-01

    A 1-MW class superconducting motor with High-Temperature Superconducting (HTS) field coil is analyzed and tested. This machine is a prototype to make sure applicability aimed at generator and industrial motor applications such as blowers, pumps and compressors installed in large plants. This machine has the HTS field coil made of Bi-2223 HTS wire and the conventional copper armature (stator) coils cooled by water. The 1-MW class HTS motor is analyzed by 3D electromagnetic Finite Element Method (FEM) to get magnetic field distribution, self and mutual inductance, and so forth. Especially excitation voltage (Back EMF) is estimated by using the mutual inductance between armature and field coils and compared with experimental result. Open and short circuit tests were conducted in generator mode while a 1.1-MW rated induction machine was rotating the HTS machine. Electrical parameters such as mutual inductance and synchronous inductance are deduced from these tests and also compared with the analysis results from FEM.

  8. Race-track coils for a 3 MW HTS ship motor

    Science.gov (United States)

    Ueno, E.; Kato, T.; Hayashi, K.

    2014-09-01

    Since the discovery of high-temperature superconductivity (HTS), Sumitomo Electric has been developing silver-sheathed Bi2223 superconducting wire and products. Ship propulsion motors are one of the most promising applications of HTS. Sumitomo Electric Industries, Ltd. (SEI) has recently manufactured 24 large racetrack coils, using 70 km long DI-BSCCO wires, for use in a 3 MW HTS motor developed by Kawasaki Heavy Industries, Ltd. (KHI). The 3 MW HTS motor, using our newly developed racetrack coils, has successfully passed the loading test. It is particularly important that the HTS field coils used in ship propulsion motors can withstand the expansive forces repeatedly applied to them. As racetrack type coils have straight sections, the support mechanism they require to withstand expansive forces is very different from that of circular coils. Therefore, we ran tests and obtained the basic data to evaluate the 20-year durability of racetrack coils against the repeatedly applied expansive forces expected in domestic ship propulsion motors.

  9. Studies on advanced superconductors for fusion device. Pt. 2. Metallic superconductors other than Nb{sub 3}Sn

    Energy Technology Data Exchange (ETDEWEB)

    Tachikawa, K.; Yamamoto, J.; Mito, T. [eds.

    1997-03-01

    A comprehensive report on the present status of the development of Nb{sub 3}Sn superconductors was published as the NIFS-MEMO-20 in March, 1996 (Part 1 of this report series). The second report of this study covers various progress so far achieved in the research and development on advanced metallic superconductors other than Nb{sub 3}Sn. Among different A15 crystal-type compounds, Nb{sub 3}Al has been fabricated into cables with large current-carrying capacity for fusion device referring its smaller sensitivity to mechanical strain than Nb{sub 3}Sn. Other high-field A15 superconductors, e.g. V{sub 3}Ga, Nb{sub 3}Ge and Nb{sub 3}(Al,Ge), have been also fabricated through different novel processes as promising alternatives to Nb{sub 3}Sn conductors. Meanwhile, B1 crystal-type NbN and C15 crystal-type V{sub 2}(Hf,Zr) high-field superconductors are characterized by their excellent tolerance to mechanical strain and neutron irradiation. Chevrel-type PbMo{sub 6}S{sub 8} compound has gained much interests due to its extremely high upper critical field. In addition, this report includes the recent progress in ultra-fine filamentary NbTi wires for AC use, and that in NbTi/Cu magnetic shields necessary in the application of high magnetic field. The data on the decay of radioactivity in a variety of metals relating to fusion superconducting magnet are also attached as appendices. We hope that this report might contribute substantially as a useful reference for the planning of fusion apparatus of next generation as well as that of other future superconducting devices. (author)

  10. High temperature superconducting compounds

    Science.gov (United States)

    Goldman, Allen M.

    1992-11-01

    The major accomplishment of this grant has been to develop techniques for the in situ preparation of high-Tc superconducting films involving the use of ozone-assisted molecular beam epitaxy. The techniques are generalizable to the growth of trilayer and multilayer structures. Films of both the DyBa2Cu3O(7-x) and YBa2Cu3O(7-x) compounds as well as the La(2-x)Sr(x)CuO4 compound have been grown on the usual substrates, SrTiO3, YSZ, MgO, and LaAlO3, as well as on Si substrates without any buffer layer. A bolometer has been fabricated on a thermally isolated SiN substrate coated with YSZ, an effort carried out in collaboration with Honeywell Inc. The deposition process facilitates the fabrication of very thin and transparent films creating new opportunities for the study of superconductor-insulator transitions and the investigation of photo-doping with carriers of high temperature superconductors. In addition to a thin film technology, a patterning technology has been developed. Trilayer structures have been developed for FET devices and tunneling junctions. Other work includes the measurement of the magnetic properties of bulk single crystal high temperature superconductors, and in collaboration with Argonne National Laboratory, measurement of electric transport properties of T1-based high-Tc films.

  11. Evaluation of methods for application of epitaxial buffer and superconductor layers

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-30

    The recent achievements of critical currents exceeding million amperes per square centimeter at 77K in YBCO deposited over suitably textured substrate have stimulated interest in the potential applications of coated conductors at high temperatures and in high magnetic fields. Currently, ion-beam assisted deposition (IBAD), and rolling assisted bi-axially textured substrate (RABiTS), represent two available options for obtaining textured substrates. For applying suitable coatings of buffer and high temperature superconductor (HTS) material over textured substrates, several options are available which include sputtering, electron-beam evaporation, laser ablation, electrophoresis, chemical vapor deposition (including metal organics chemical vapor deposition), sol-gel, metal organics decomposition, electrodeposition and aerosol/spray pyrolysis. A commercial continuous long-length wire/tape manufacturing scheme developed out of any suitable combination of the above techniques would consist of operations involving preparation of the substrate and application of buffer, HTS and passivation/insulation materials and special treatment steps such as post-annealing. These operations can be effected by various process parameters that can be classified into chemistry, materials, engineering and environmental related parameters. Under the DOE-sponsored program, to carry out an engineering evaluation, first, the process flow schemes were developed for various candidate options identifying the major operating steps, process conditions, and process streams. Next, to evaluate quantifiable parameters such as process severity (e.g. temperature and pressure), coating thickness and deposition rate for HTS material, achieved maximum J{sub c} value (for films >1{micro}m thick) and cost of chemical and material utilization efficiency, the multi-attribute method was used to determine attributes/merits for various parameters and candidate options. To determine similar attribute values for the

  12. Development, characterization, and applications of high temperature superconductor nanobridge Josephson junctions

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, J.R.; Tigges, C.P.; Hietala, V.M.; Plut, T.A. [Sandia National Labs., Albuquerque, NM (United States); Martens, J.S.; Char, K.; Johansson, M.E. [Conductus, Inc., Sunnyvale, CA (United States)

    1994-03-01

    A well-controlled, high-yield Josephson junction process in high temperature superconductors (HTS) is necessary for the demonstration of ultra-high-speed devices and circuits which exceed the capabilities of conventional electronics. The authors developed nanobridge Josephson junctions in high quality thin-film YBaCuO with dimensions below 100 nm fabricated using electron-beam nanolithography. They characterized this Josephson junction technology for process yield, junction parameter uniformity, and overall applicability for use in high-performance circuits. To facilitate the determination of junction parameters, they developed a measurement technique based on spectral analysis in the range of 90--160 GHz of phase-locked, oscillating arrays of up to 2,450 Josephson junctions. Because of the excellent yield and uniformity of the nanobridge junctions, they successfully applied the junction technology to a wide variety of circuits. These circuits included transmission-line pulse formers and 32 and 64-bit shift registers. The 32-bit shift register was shown to operate at clock speeds near 100 GHz and is believed to be one of the faster and more complex digital circuit demonstrated to date using high temperature superconductor technology.

  13. Isotropic round-wire multifilament cuprate superconductor for generation of magnetic fields above 30 T

    CERN Document Server

    Larbalestier, D C; Trociewitz, U P; Kametani, F; Scheuerlein, C; Dalban-Canassy, M; Matras, M; Chen, P; Craig, N C; Lee, P J; Hellstrom, E E

    2014-01-01

    Magnets are the principal market for superconductors, but making attractive conductors out of the high-temperature cuprate superconductors (HTSs) has proved difficult because of the presence of high-angle grain boundaries that are generally believed to lower the critical current density, J$_c$. To minimize such grain boundary obstacles, HTS conductors such as REBa$_2$Cu$_3$O$_{7−x}$ and (Bi, Pb)$_2$Sr$_2$Ca$_2$Cu$_3$O$_{10−x}$ are both made as tapes with a high aspect ratio and a large superconducting anisotropy. Here we report that Bi$_2$2Sr$_2$CaCu$_2$O$_{8−x}$ (Bi-2212) can be made in the much more desirable isotropic, round-wire, multifilament form that can be wound or cabled into arbitrary geometries and will be especially valuable for high-field NMR magnets beyond the present 1 GHz proton resonance limit of Nb$_3$Sn technology. An appealing attribute of this Bi-2212 conductor is that, being without macroscopic texture, it contains many high-angle grain boundaries but nevertheless attains a very hi...

  14. Hysteresis force loss and damping properties in a practical magnet-superconductor maglev test vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Yang Wenjiang; Liu Yu; Wen Zheng; Chen Xiaodong; Duan Yi [School of Astronautics, Beijing University of Aeronautics and Astronautics, Beijing 100083 (China)

    2008-01-15

    In order to investigate the feasible application of a permanent magnet-high-temperature superconductor (PM-HTS) interaction maglev system to a maglev train or a space vehicle launcher, we have constructed a demonstration maglev test vehicle. The force dissipation and damping of the maglev vehicle against external disturbances are studied in a wide range of amplitudes and frequencies by using a sine vibration testing set-up. The dynamic levitation force shows a typical hysteresis behavior, and the force loss is regarded as the hysteresis loss, which is believed to be due to flux motions in superconductors. In this study, we find that the hysteresis loss has weak frequency dependence at small amplitudes and that the dependence increases as the amplitude grows. To analyze the damping properties of the maglev vehicle at different field cooling (FC) conditions, we also employ a transient vibration testing technique. The maglev vehicle shows a very weak damping behavior, and the damping is almost unaffected by the trapped flux of the HTSs in different FC conditions, which is believed to be attributed to the strong pinning in melt-textured HTSs.

  15. Hysteresis force loss and damping properties in a practical magnet superconductor maglev test vehicle

    Science.gov (United States)

    Yang, Wenjiang; Liu, Yu; Wen, Zheng; Chen, Xiaodong; Duan, Yi

    2008-01-01

    In order to investigate the feasible application of a permanent magnet-high-temperature superconductor (PM-HTS) interaction maglev system to a maglev train or a space vehicle launcher, we have constructed a demonstration maglev test vehicle. The force dissipation and damping of the maglev vehicle against external disturbances are studied in a wide range of amplitudes and frequencies by using a sine vibration testing set-up. The dynamic levitation force shows a typical hysteresis behavior, and the force loss is regarded as the hysteresis loss, which is believed to be due to flux motions in superconductors. In this study, we find that the hysteresis loss has weak frequency dependence at small amplitudes and that the dependence increases as the amplitude grows. To analyze the damping properties of the maglev vehicle at different field cooling (FC) conditions, we also employ a transient vibration testing technique. The maglev vehicle shows a very weak damping behavior, and the damping is almost unaffected by the trapped flux of the HTSs in different FC conditions, which is believed to be attributed to the strong pinning in melt-textured HTSs.

  16. Josephson Current in Superconductor-Ferromagnet/Insulator/d-Wave Superconductor Junctions

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-Wei; DONG Zheng-Chao

    2005-01-01

    Solving the Bogoliubov-de Gennes equation, the energy levels of bound states are obtained in the ferromagnetic superconductor. The Josephson currents in a ferromagnetic superconductor/Insulator/d-wave superconductor junction are calculated as a function of the exchange field, temperature, and insulating barrier strength. It is found that the Josephson critical current is always suppressed by the presence of exchange field h and depends on crystalline axis orientation of d-wave superconductor.

  17. Analysis of a ToxCast™ HTS Toxicity Signature for putative Vascular Disruptor Compounds

    Science.gov (United States)

    Recent studies have shown the importance of blood vessel formation during embryo development and the strong correlation to developmental toxicity. Several developmental toxicants, such as thalidomide, have been identified which specifically target the forming embryonic vasculatur...

  18. Iron-Based Superconductors as Odd-Parity Superconductors

    Directory of Open Access Journals (Sweden)

    Jiangping Hu

    2013-07-01

    Full Text Available Parity is a fundamental quantum number used to classify a state of matter. Materials rarely possess ground states with odd parity. We show that the superconducting state in iron-based superconductors is classified as an odd-parity s-wave spin-singlet pairing state in a single trilayer FeAs/Se, the building block of the materials. In a low-energy effective model constructed on the Fe square bipartite lattice, the superconducting order parameter in this state is a combination of an s-wave normal pairing between two sublattices and an s-wave η pairing within the sublattices. The state has a fingerprint with a real-space sign inversion between the top and bottom As/Se layers. The results suggest that iron-based superconductors are a new quantum state of matter, and the measurement of the odd parity can help to establish high-temperature superconducting mechanisms.

  19. Iron Pnictide Superconductors: discovery and advances

    Science.gov (United States)

    Hosono, Hideo

    2009-03-01

    Superconducting transition in a layered ZrCuSiAs-type crystal was first reported for LaFePO in 2006 [1] and subsequently, a similar Tc was found for LaNiPO with the same crystal structure in 2007. However, Tc of these compounds reminded low (˜4K). On February 23, 2008, our paper reporting a layered compound in LaFeAsO1-xFx(x=0.1) exhibiting a superconducting critical temperature Tc (mid-point) = 26K was published [3]. In this presentation I talk the background of this discovery and the subsequent advance in materials. The following points have been clarified to date; (1) Iron-based superconductors reported are 4-types crystal structures, the 1111[3], 122[4], 111[5], and 11 [6] type. All the high Tc iron-based superconductors contain a Fe square lattice and the Fe 3d orbitals dominate the Fermi-level. (2) The occurrence of a crystallographic transition accompanying anti-ferromagnetic to paramagnetic state in the parent compound is a requisite for a high Tc. (3) There exist a vast number of materials containing the Fe square lattice. (4). A partial substitution of Fe with other transition metal is possible without serious reduction of Tc. (4) A new insulating layer AEF (AE=Ca, Sr)was found to be effective in the 1111 phase [7]. (5) High pressure synthesis was effective to obtain the 1111 phases with higher Tc, (6) Epitaxial thin films exhibiting a Tc almost the same as that in the bulk were fabricated for CaFeAsO:Co[8]. Epitaxial thin films of LaFeAsO was recently reported as well [9]. [4pt] [1] Y.Kamihara et al. JACS, 28 (2006)10012, [2] T.Watanabe et al.Inorg.Chem,46(2007) 7719, [3 ]Y.Kamihara et al. J.Am.Chem.Soc.130(2008)3296., [4]M.Rotter et al. PRL, 101(2008) 107006, [5] J.H.Tapp et al. PRB,78(2008)060505 [6] F.C.Hsu et al. PNAS,105(2008)14262., [7] S.Matsuishi et al. JACS 130(2008)14428 [8] H.Hiramatsu et al. Appl.Phys.Express 1(2008)101702, [9] H.Hiramatsu et al. APL. 93(2008) 162504.

  20. Current status of iron-based superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kamihara, Yoichi, E-mail: kamihara_yoichi@appi.keio.ac.jp [Keio University, Department of Applied Physics and Physico-Informatics, Faculty of Science and Technology (Japan)

    2012-03-15

    Current status of iron-based superconductors is summarized. Although short range magnetic ordering and magnetic phase separation of Fe are controversial, (long range) magnetic and electronic phase diagrams of iron based superconductors can be classified into two-type. Antiferromagnetic ordering of itinerant Fe does not coexist with superconducting phase of SmFeAsO{sub 1 - x}F{sub x}. The very large H{sub c2} of iron-based superconductors attract us to attempts at applications.

  1. Current status of iron-based superconductors

    Science.gov (United States)

    Kamihara, Yoichi

    2012-03-01

    Current status of iron-based superconductors is summarized. Although short range magnetic ordering and magnetic phase separation of Fe are controversial, (long range) magnetic and electronic phase diagrams of iron based superconductors can be classified into two-type. Antiferromagnetic ordering of itinerant Fe does not coexist with superconducting phase of SmFeAsO1 - xFx. The very large H c2 of iron-based superconductors attract us to attempts at applications.

  2. A Road Towards High Temperature Superconductors

    Science.gov (United States)

    2013-08-01

    AFRL-AFOSR-UK-TR-2013-0040 A Road Towards High Temperature Superconductors Guy Deutscher Tel Aviv University Research... Superconductors 5a. CONTRACT NUMBER FA8655-10-1-3011 5b. GRANT NUMBER Grant 10-3011 5c. PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S...issue in trying to make useful high temperature superconductors is obviously to discover superconductivity at higher temperatures. But there is also

  3. Holographic complexity in gauge/string superconductors

    Directory of Open Access Journals (Sweden)

    Davood Momeni

    2016-05-01

    Full Text Available Following a methodology similar to [1], we derive a holographic complexity for two dimensional holographic superconductors (gauge/string superconductors with backreactions. Applying a perturbation method proposed by Kanno in Ref. [2], we study behaviors of the complexity for a dual quantum system near critical points. We show that when a system moves from the normal phase (T>Tc to the superconductor phase (T

  4. Test results of the 18 kA EDIPO HTS current leads

    Energy Technology Data Exchange (ETDEWEB)

    Wesche, Rainer, E-mail: rainer.wesche@psi.ch [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), Association Euratom - Confederation Suisse, 5232 Villigen PSI (Switzerland); Bagnasco, Maurizio; Bruzzone, Pierluigi; Felder, Roland; Guetg, Marc; Holenstein, Manuel; Jenni, Markus; March, Stephen; Roth, Felix; Vogel, Martin [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), Association Euratom - Confederation Suisse, 5232 Villigen PSI (Switzerland)

    2011-10-15

    For the new test facility EDIPO (European DIPOle), to be hosted by CRPP, two 18 kA HTS current leads were manufactured and successfully tested. The HTS module, made of AgMgAu/Bi-2223 tapes, is cooled only by heat conduction to the cold end, while the copper part is cooled by forced flow helium gas. The current leads were tested at low voltage up to the maximum current of 18 kA. The helium mass flow rates required for stable operation at various currents were determined. In addition to the steady state operation, the transient behavior in the case of a loss of flow was studied experimentally. The test results provide an estimate of the operational limits of the EDIPO HTS current leads.

  5. Cancer and virus leads by HTS, chemical design and SEA data mining.

    Science.gov (United States)

    Thepchatri, Pahk; Min, Jaeki; Ganesh, Thota; Du, Yuhong; Lewis, Iestyn; Kurtkaya, Serdar; Prussia, Andrew; Li, Lian; Sneed, Blossom; Plemper, Richard K; Fu, Haian; Liotta, Dennis C; Snyder, James P; Dingledine, Raymond; Sun, Aiming

    2009-01-01

    A variety of medicinal chemistry approaches can be used for the identification of hits, generation of leads and to accelerate the development of drug candidates. The Emory Chemical and Biology Discovery Center (ECBDC) has been an active participant in the NIH's high-throughput screening (HTS) endeavor to identify potent small molecule probes for poorly studied proteins. Several of Emory's projects relate to cancer or virus infection. We have chosen three successful examples including discovery of potent measles virus RNA-dependent RNA polymerase inhibitors, development of Heat Shock Protein 90 (Hsp90) blockers and identification of angiogenesis inhibitors using transgenic Zebrafish as a HTS model. In parallel with HTS, a unique component of the Emory virtual screening (VS) effort, namely, substructure enrichment analysis (SEA) program has been utilized in several cases.

  6. Temperature dependency of magnetic field drifts of HTS pancake coils for NMR/MRI applications

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kyeong Dal; Lee, Se Yeon; Kim, Woo Seok [Dept. of Energy and Electrical Engineering, Korea Polytechnic University, Siheung (Korea, Republic of); Lee, Sang Min [Dept. of Radiology, CHA Bundang Medical Center, CHA University, Seongnam (Korea, Republic of)

    2013-12-15

    We had proposed a winding method so called “Wind-and-Flip”, which enables a persistent current operation of an HTS pancake coil without any electrical joint. In order to improve the magnetic field drift characteristics, a prototype HTS coil with the technique was fabricated, and tested under various temperatures. Because the coil does not have any electric terminals for current leads, an HTS background magnet was used to induce the persistent current in the coil by field cooling process. A conduction cooling system with a GM cryocooler was prepared to keep the operating temperatures of the prototype coil much below the 77 K. We investigated the magnetic field drift characteristics under the various operating temperatures by measuring the center magnetic field with a cryogenic Hall sensor. The persistent current mode operation at 20 ∽ 50K showed a strong possibility of the winding technique for the application such as MRI or NMR.

  7. Frequency dependence of magnetic shielding performance of HTS plates in mixed states

    Energy Technology Data Exchange (ETDEWEB)

    Kamitani, Atsushi; Yokono, Takafumi [Yamagata Univ., Yonezawa (Japan). Faculty of Engineering; Yokono, Takafumi [Tsukuba Univ., Ibaraki (Japan). Inst. of Information Sciences and Electronics

    2000-06-01

    The magnetic shielding performance of the high-Tc superconducting (HTS) plate is investigated numerically. The behavior of the shielding current density in the HTS plate is expressed as the integral-differential equation with a normal component of the current vector potential as a dependent variable. The numerical code for solving the equation has been developed by using the combination of the Newton-Raphson method and the successive substitution method and, by use of the code, damping coefficients and shielding factors are evaluated for the various values of the frequency {omega}. The results of computations show that the HTS plate has a possibility of shielding the high-frequency magnetic field with {omega} > or approx. 1 kHz. (author)

  8. Controller design and test results for a four axis HTS coil based Maglev system

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Tong [Department of Automation, Tsinghua University, Beijing 100084 (China)]. E-mail: tzhou@mail.tsinghua.edu.cn; Xing Huawei [Department of Automation, Tsinghua University, Beijing 100084 (China)

    2007-04-15

    Controller design and experimental results are reported in this paper for a four axis high temperature superconductivity (HTS) coil based electromagnetic levitation (Maglev) system. The HTS coils are made of Bi2223/Ag multifilamentary tapes. It has been experimentally proved that the designed controller works satisfactorily, although the physical parameters of a HTS coil based electromagnet (HTSEM) vary significantly with the frequency of the input voltage. A performance comparison has also been made between the classical lead-lag compensator and the modern H{sub {approx}} loop-shaping controller. It becomes clear that robust control theories are capable of providing a controller with better performances, which is in a good agreement with numerical simulations. Moreover, it implies that the particular parameter variation characteristics can be simply dealt with by the available robust control theories that are naturally existent in a HTSEM.

  9. Experimental Consequences of Mottness in High-Temperature Copper-Oxide Superconductors

    Science.gov (United States)

    Chakraborty, Shiladitya

    2009-01-01

    It has been more than two decades since the copper-oxide high temperature superconductors were discovered. However, building a satisfactory theoretical framework to study these compounds still remains one of the major challenges in condensed matter physics. In addition to the mechanism of superconductivity, understanding the properties of the…

  10. Critical currents and thermally activated flux motion in high-temperature superconductors

    NARCIS (Netherlands)

    Palstra, T.T.M.; Batlogg, B.; Dover, R.B. van; Schneemeyer, L.F.; Waszczak, J.V.

    1989-01-01

    We have measured the resistance below Tc of single crystals of the high-temperature superconductors Ba2YCu3O7 and Bi2.2Sr2Ca0.8Cu2O8+δ in magnetic fields up to 12 T. The resistive transition of both compounds is dominated by intrinsic dissipation which is thermally activated, resulting in an exponen

  11. Recent progress on carbon-based superconductors.

    Science.gov (United States)

    Kubozono, Yoshihiro; Eguchi, Ritsuko; Goto, Hidenori; Hamao, Shino; Kambe, Takashi; Terao, Takahiro; Nishiyama, Saki; Zheng, Lu; Miao, Xiao; Okamoto, Hideki

    2016-08-24

    This article reviews new superconducting phases of carbon-based materials. During the past decade, new carbon-based superconductors have been extensively developed through the use of intercalation chemistry, electrostatic carrier doping, and surface-proving techniques. The superconducting transition temperature T c of these materials has been rapidly elevated, and the variety of superconductors has been increased. This review fully introduces graphite, graphene, and hydrocarbon superconductors and future perspectives of high-T c superconductors based on these materials, including present problems. Carbon-based superconductors show various types of interesting behavior, such as a positive pressure dependence of T c. At present, experimental information on superconductors is still insufficient, and theoretical treatment is also incomplete. In particular, experimental results are still lacking for graphene and hydrocarbon superconductors. Therefore, it is very important to review experimental results in detail and introduce theoretical approaches, for the sake of advances in condensed matter physics. Furthermore, the recent experimental results on hydrocarbon superconductors obtained by our group are also included in this article. Consequently, this review article may provide a hint to designing new carbon-based superconductors exhibiting higher T c and interesting physical features.

  12. Melt processed high-temperature superconductors

    CERN Document Server

    1993-01-01

    The achievement of large critical currents is critical to the applications of high-temperature superconductors. Recent developments have shown that melt processing is suitable for producing high J c oxide superconductors. Using magnetic forces between such high J c oxide superconductors and magnets, a person could be levitated.This book has grown largely out of research works on melt processing of high-temperature superconductors conducted at ISTEC Superconductivity Research Laboratory. The chapters build on melt processing, microstructural characterization, fundamentals of flux pinning, criti

  13. Characteristics of the magnetic field distribution on compact NMR magnets using cryocooled HTS bulks

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.B., E-mail: kim@elec.okayama-u.ac.j [Department of Electrical and Electronic Engineering, Okayama University, 3-1-1, Tsushima Naka, Okayama 700-8530 (Japan); Takano, R.; Nakano, T.; Imai, M. [Department of Electrical and Electronic Engineering, Okayama University, 3-1-1, Tsushima Naka, Okayama 700-8530 (Japan); Hahn, S.Y. [Francis Bitter Magnet Laboratory, MIT, NW14-3117, 170 Albany Street, Cambridge, MA 02139 (United States)

    2009-10-15

    Recently, the performance of high temperature superconducting (HTS) bulks such as critical current density, size, and mechanical strength has been improved rapidly. So, various applications using HTS bulks such as motors, bearings and flywheels have been investigated by many research groups. A compact nuclear magnetic resonance (NMR) magnet is one of the new applications after a technique to enhance maximum trapped field of the HTS bulk more than 11.7 T (500 MHz {sup 1}H NMR frequency) has been developed. This new compact NMR magnet out of HTS bulks is cost-effective compared with conventional NMR magnets and then expected to be widely used in food and drug industry. In design and manufacture of the compact NMR magnets, spatial field homogeneity of the large trapped magnetic field in HTS bulk annuli is a crucial issue because the behavior of a trapped field is highly non-linear and, as a result, a technique to improve the field homogeneity such as active/passive shimming now becomes more challenging compared with that of the conventional counterparts. This paper presents the magnetic field distributions in single and three assembled HTS bulk annuli measured by a 3-axis and multi-arrayed Hall sensor under two different cryogenic environments: (1) in a bath of liquid nitrogen (LN{sub 2}) and (2) dry cooling by a cryocooler. The spatial homogeneity changes with various operating temperatures were investigated and the effect of critical current density enhancement by lowering the operating temperature on the field homogeneity improvement was discussed in detail.

  14. Temperature Distribution and Critical Current of Long HTS Cables Cooled with Subcooled Liquid Nitrogen

    Science.gov (United States)

    Vyatkin, V. S.; Ivanov, Y. V.; Watanabe, H.; Chikumoto, N.; Yamaguchi, S.

    2017-07-01

    Cooling of the long HTS power transmission lines performs by pumping of subcooled liquid nitrogen (LN2) along the cable. The temperature of LN2 along the cable increases due to the heat losses of the cryostat and heat generation in the HTS cable. The experiment using test cable line in Ishikari shows that flow rate of 35 L/min retains increasing of LN2 temperature by 1 K per 1 km of length. The technology when the back flow of LN2 cools the radiation shield surrounding the cable pipe is also applied in Ishikari-2 project. In this case the ambient heat flow into cable pipe is 50 times less than that without radiation shield. Back flow of LN2 removes almost all heat coming from the environment. When transport current is close to the critical value the Joule heat of HTS cable is significant. This heat additionally increases the temperature of LN2 flowing along the HTS cable. Near the outlet the temperature of HTS cable is maximal and the local critical current is minimal. The current matching critical current criterion of average electrical field of E 0 = 10-4 V/m provides the voltage drop and significant Joule heat at the hot end of the cable. It can lead the damage of the cable. The present work contains analysis of temperature distribution along the cable and the way to achieve the fail-safe operation of long HTS cable cooled by subcooled LN2. We also performed extrapolation of obtained results for several times longer cable lines by decreasing the LN2 flow rate.

  15. Interfacial bonding enhancement of reel-to-reel selective electrodeposition of copper stabilizer on a multifilamentary second-generation high-temperature superconductor tape

    Science.gov (United States)

    Cai, Xinwei; Li, Wei; Bose, Anima; Selvamanickam, Venkat

    2016-10-01

    A reel-to-reel copper selective electrodeposition process over a multifilamentary second-generation high-temperature superconductor (2G-HTS) has been demonstrated in our previous work. If the interfacial bonding between the deposited copper layer and the underlying silver overlayer is weak, it might lead to delamination in applications including magnets, motors and generators. In this study, two approaches have been used to improve the copper-silver bonding without the degradation of superconductor performance. The first approach is acidifying the electrolyte by adding sulfuric acid, by which the kinetics of copper electrodeposition is enhanced, resulting in finer microstructure at the copper-silver interface and thus, improved interfacial bonding strength. The second approach consists of blocking the electrolyte outflow at the entrance of the reel-to-reel electroplating cell, by which the occurrence of large copper seeds on the tape caused by the heavy turbulence flow is effectively prevented. With these two improvements together deployed in the process, the peeling strength between the copper and silver layers of the 2G-HTS tape has been improved from 2 N in 90° peeling and from 3.0 N in 180° peeling, without any degradation on the superconducting performance.

  16. Shielding superconductors with thin films

    CERN Document Server

    Posen, Sam; Catelani, Gianluigi; Liepe, Matthias U; Sethna, James P

    2015-01-01

    Determining the optimal arrangement of superconducting layers to withstand large amplitude AC magnetic fields is important for certain applications such as superconducting radiofrequency cavities. In this paper, we evaluate the shielding potential of the superconducting film/insulating film/superconductor (SIS') structure, a configuration that could provide benefits in screening large AC magnetic fields. After establishing that for high frequency magnetic fields, flux penetration must be avoided, the superheating field of the structure is calculated in the London limit both numerically and, for thin films, analytically. For intermediate film thicknesses and realistic material parameters we also solve numerically the Ginzburg-Landau equations. It is shown that a small enhancement of the superheating field is possible, on the order of a few percent, for the SIS' structure relative to a bulk superconductor of the film material, if the materials and thicknesses are chosen appropriately.

  17. First tests of a 800 kJ HTS SMES

    CERN Document Server

    Tixador, Pascal; Badel, Arnaud; Berger, Kévin; Bellin, Boris; Vallier, Jean-Claude; Allais, Arnaud; Bruzek, Christian-Eric; 10.1109/TASC.2008.921319

    2008-01-01

    SMES using high critical temperature superconductors are interesting for high power pulsed sources. Operation at temperatures above 20 K makes cryogenics easier, enhances stability and improves operation as pulsed power source. In the context of a DGA (Delegation Generate pour l'Armement) project, we have designed and constructed a 800 kJ SMES. The coil is wound with Nexans conductors made of Bi-2212 PIT tapes soldered in parallel. The coil consists in 26 superposed simple pancakes wound and bonded on sliced copper plates coated with epoxy. The rated current is 315 A for an energy of 814 kJ. The external diameter of the coil is 814 mm and its height 222 mm. The cooling at 20 K is only performed by conduction from cryocoolers to make cryogenics very friendly and invisible for the SMES users. The cooling down has been successfully carried out and the thermal system works as designed. After a brief description of the SMES design and construction, some tests will be presented. From a current of 244 A, the SMES de...

  18. Design and Comparison of a 1 MW / 5s HTS SMES with Toroidal and Solenoidal Geometry

    CERN Document Server

    Morandi, Antonio; Gholizad, Babak; Grilli, Francesco; Sirois, Frédéric; Zermeño, Víctor M R

    2015-01-01

    The design of a HTS SMES coil with solenoidal and toroidal geometry is carried out based on a commercially available 2G HTS conductor. A SMES system of practical interest (1 MW / 5 s) is considered. The comparison between ideal toroidal and solenoidal geometry is first discussed and the criteria used for choosing the geometrical parameters of the coils' bore are explained. The design of the real coil is then carried out and the final amount of conductor needed is compared. A preliminary comparison of the two coils in terms of AC loss during one charge discharge cycle is also discussed.

  19. HTS filter and front-end subsystem for GSM1800 wireless base station

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The first HTS front-end subsystem for wireless base station in China was developed. This demonstration system, which aims at the application in GSM1800 mobile communication base station, consists of a single RF path, i.e. one filter and one LNA, integrated with the pulse tube cooler. The subsystem works at a pass band of 1710-1785 MHz with a gain of 18 dB and at a temperature of 70 K. The accomplishment of such a demonstration subsystem can boost the development of HTS commercial subsystem.

  20. Assembly and testing of a composite heat pipe thermal intercept for HTS current leads

    Energy Technology Data Exchange (ETDEWEB)

    Daugherty, M.A.; Daney, D.E.; Prenger, F.C.; Hill, D.D.; Williams, P.M.; Boenig, H.J.

    1995-09-01

    We are building high temperature superconducting (HTS) current leads for a demonstration HTS-high gradient magnetic separation (HGMS) system cooled by a cryocooler. The current leads are entirely conductively cooled. A composite nitrogen heat pipe provides efficient thermal communication, and simultaneously electrical isolation, between the lead and an intermediate temperature heat sink. Data on the thermal and electrical performance of the heat pipe thermal intercept are presented. The electrical isolation of the heat pipe was measured as a function of applied voltage with and without a thermal load across the heat pipe. The results show the electrical isolation with evaporation, condensation and internal circulation taking place in the heat pipe.

  1. Assembly and testing of a composite heat pipe thermal intercept for HTS current leads

    Energy Technology Data Exchange (ETDEWEB)

    Daugherty, M.A.; Daney, D.E.; Prenger, F.C. [Los Alamos National Lab., NM (United States)] [and others

    1996-12-31

    The authors are building high temperature superconducting (HTS) current leads for a demonstration HTS high gradient magnetic separation (HGMS) system cooled by a cryocooler. The current leads are entirely conductively cooled. A composite nitrogen heat pipe provides efficient thermal communication, and simultaneously electrical isolation, between the lead and an intermediate temperature heat sink. Data on the thermal and electrical performance of the heat pipe thermal intercept are presented. The electrical isolation of the heat pipe was measured as a function of applied voltage with and without a thermal load across the heat pipe. The results show the electrical isolation with evaporation, condensation and internal circulation taking place in the heat pipe.

  2. Temperature Distribution Analysis of JAERI 60 kA HTS Lead

    Institute of Scientific and Technical Information of China (English)

    FUYoukun; T.Isono

    2003-01-01

    High temperature suprerconductor (HTS)current lead has an advantage in reducing electric power consumption of a refrigerator for a large current superconducting magnet system such as a fusion device. A fusion device requires more than 20 pairs of large current leads and each current capacity is about 60 kA. The conventional 60 kA current lead needs 100 kW electric power for refrigeration and a 2/3 reduction is available by the application of a HTS current lead.

  3. A computer-aided method for postproduction tuning of HTS filters

    Energy Technology Data Exchange (ETDEWEB)

    Zuo Tao; Fang Lan; Yan Shaolin; Zhao Xinjie; Zhou Tiege; You Shitou; Ma Weigang; Yue Hongwei; Xie Qinglian [Department of Electronics, Nankai University, Tianjin 300071 (China)

    2007-12-15

    The empirical tuning of high temperature superconducting (HTS) filters is usually time-consuming and expensive. A computer-aided tuning method is presented in this paper. By means of optimization, the method diagnoses detuning of individual resonators quantitatively in the tuning process, and then by using neural network models the method is able to give the operator a decision on how much the corresponding tuning screws should be tuned. So, compared with the empirical tuning method, this method can be used to tune the HTS filters accurately with less time and cost.

  4. Assessing HTS performance using BioAssay Ontology: screening and analysis of a bacterial phospho-N-acetylmuramoyl-pentapeptide translocase campaign.

    Science.gov (United States)

    Moberg, Andreas; Zander Balderud, Linda; Hansson, Eva; Boyd, Helen

    2014-01-01

    With the public availability of biochemical assays and screening data constantly increasing, new applications for data mining and method analysis are evolving in parallel. One example is BioAssay Ontology (BAO) for systematic classification of assays based on screening setup and metadata annotations. In this article we report a high-throughput screening (HTS) against phospho-N-acetylmuramoyl-pentapeptide translocase (MraY), an attractive antibacterial drug target involved in peptidoglycan synthesis. The screen resulted in novel chemistry identification using a fluorescence resonance energy transfer assay. To address a subset of the false positive hits, a frequent hitter analysis was performed using an approach in which MraY hits were compared with hits from similar assays, previously used for HTS. The MraY assay was annotated according to BAO and three internal reference assays, using a similar assay design and detection technology, were identified. Analyzing the assays retrospectively, it was clear that both MraY and the three reference assays all showed a high false positive rate in the primary HTS assays. In the case of MraY, false positives were efficiently identified by applying a method to correct for compound interference at the hit-confirmation stage. Frequent hitter analysis based on the three reference assays with similar assay method identified additional false actives in the primary MraY assay as frequent hitters. This article demonstrates how assays annotated using BAO terms can be used to identify closely related reference assays, and that analysis based on these assays clearly can provide useful data to influence assay design, technology, and screening strategy.

  5. Theoretical studies of unconventional superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Groensleth, Martin Sigurd

    2008-07-01

    This thesis presents four research papers. In the first three papers we have derived analytical results for the transport properties in unconventional superconductors and ferromagnetic systems with multiple broken symmetries. In Paper I and parts of Paper II we have studied tunneling transport between two non-unitary ferromagnetic spin-triplet superconductors, and found a novel interplay between ferromagnetism and superconductivity manifested in the Josephson effect as a spin- and charge-current in the absence of an applied voltage across the junction. The critical amplitudes of these currents can be adjusted by the relative magnetization direction on each side of the junction. Furthermore, in Paper II, we have found a way of controlling a spin-current between two ferromagnets with spin-orbit coupling. Paper III considers a junction consisting of a ferromagnet and a non-unitary ferromagnetic superconductor, and we show that the conductance spectra contains detailed information about the superconducting gaps and pairing symmetry of the Cooper-pairs. In the last paper we present a Monte Carlo study of an effective Hamiltonian describing orbital currents in the CuO2 layers of high-temperature superconductive cuprates. The model features two intrinsically anisotropic Ising models, coupled through an anisotropic next-nearest neighbor interaction, and an Ashkin-Teller nearest neighbor fourth order coupling. We have studied the specific heat anomaly, as well as the anomaly in the staggered magnetization associated with the orbital currents and its susceptibility. We have found that in a limited parameter regime, the specific heat anomaly is substantially suppressed, while the susceptibility has a non-analytical peak across the order-disorder transition. The model is therefore a candidate for describing the breakup of hidden order when crossing the pseudo-gap line on the under-doped side in the phase diagram of high-temperature superconductors. (Author) 64 refs., figs

  6. Generalized Superconductors and Holographic Optics

    CERN Document Server

    Mahapatra, Subhash; Sarkar, Tapobrata

    2013-01-01

    We study generalized holographic s-wave superconductors in four dimensional R-charged black hole backgrounds, in the probe limit. We first establish the superconducting nature of the boundary theory, and then study its optical properties. Numerical analysis indicates that a negative index of refraction appears at low frequencies in the theory, for certain temperature ranges, for specific values of the charge parameter. The corresponding cut-off values for these are numerically established in several cases.

  7. Holographic superconductors with Weyl corrections

    Science.gov (United States)

    Momeni, Davood; Raza, Muhammad; Myrzakulov, Ratbay

    2016-10-01

    A quick review on the analytical aspects of holographic superconductors (HSCs) with Weyl corrections has been presented. Mainly, we focus on matching method and variational approaches. Different types of such HSC have been investigated — s-wave, p-wave and Stúckelberg ones. We also review the fundamental construction of a p-wave type, in which the non-Abelian gauge field is coupled to the Weyl tensor. The results are compared from numerics to analytical results.

  8. Preparation and characterization of superconductor thin films for application in printed circuit boards

    Energy Technology Data Exchange (ETDEWEB)

    Souza, G.A.; Carvalho, C.L.; Torsoni, G.B.; Rodrigues, V.D.; Souza, E.J.; Zadorosny, R. [UNESP, Ilha Solteira, SP (Brazil). Fac. de Engenharia. Grupo de Desenvolvimento e Aplicacoes de Materiais (GDAM)

    2011-07-01

    Full text: Since the discovery of high temperature superconductors (HTS) many studies have been performed, in terms to discover new materials with higher critical temperature and its potential applications. Technological advances have induced to use superconductor materials in the development of new devices that have higher processing speed, storage capacity and are miniaturized, what may imply in great evolution in the electronic area. Thinking about that advances and looking to supply some requirements, this work proposed to prepare a printed circuit board (PCB) with a superconductor thin film using an inexpensive and conventional photographic method. This work was divided in two steps: synthesis of the precursor solution and film preparation for superconductor printed circuit. In the preparation of superconductor thin film was considered to use the 2223 phase of the BSCCO system, which has been doped with Pb (BPSCCO) for stabilizing the same, and it presents a critical temperature around 110 K. This film was prepared from a precursor solution based on similar method developed by M. P. Pechini. The printed circuit was created by the photographic method of heat transfer which consisted of creation a circuit layout, with different dimensions and printed on photo paper (Epson S041140). The layout was transferred to the FR4 printed copper clad laminate was made with the household clothes iron. The precursor solution was deposited on Si substrate by spin-coating. The control of film thickness was performed by the deposition number that in this case was done five subsequent depositions to obtain an ideal thickness. Between each deposition the film was submitted to calcinations in order to eliminate organic matter. After that the film was submitted a heat treatment around 820 deg C / 5 minutes to obtain the expected superconducting phase and coupling and the grain growth. Film characterizations were made using optical microscopy, XRD and EDX, to check the dimensions and

  9. Edge instabilities of topological superconductors

    Science.gov (United States)

    Hofmann, Johannes S.; Assaad, Fakher F.; Schnyder, Andreas P.

    2016-05-01

    Nodal topological superconductors display zero-energy Majorana flat bands at generic edges. The flatness of these edge bands, which is protected by time-reversal and translation symmetry, gives rise to an extensive ground-state degeneracy. Therefore, even arbitrarily weak interactions lead to an instability of the flat-band edge states towards time-reversal and translation-symmetry-broken phases, which lift the ground-state degeneracy. We examine the instabilities of the flat-band edge states of dx y-wave superconductors by performing a mean-field analysis in the Majorana basis of the edge states. The leading instabilities are Majorana mass terms, which correspond to coherent superpositions of particle-particle and particle-hole channels in the fermionic language. We find that attractive interactions induce three different mass terms. One is a coherent superposition of imaginary s -wave pairing and current order, and another combines a charge-density-wave and finite-momentum singlet pairing. Repulsive interactions, on the other hand, lead to ferromagnetism together with spin-triplet pairing at the edge. Our quantum Monte Carlo simulations confirm these findings and demonstrate that these instabilities occur even in the presence of strong quantum fluctuations. We discuss the implications of our results for experiments on cuprate high-temperature superconductors.

  10. Is a color superconductor topological?

    CERN Document Server

    Nishida, Yusuke

    2010-01-01

    A fully gapped state of matter, whether insulator or superconductor, can be asked if it is topologically trivial or nontrivial. Here we investigate topological properties of superconducting Dirac fermions in 3D having a color superconductor as an application. In the chiral limit, when the pairing gap is parity even, the right-handed and left-handed sectors of the free space Hamiltonian have nontrivial topological charges with opposite signs. Accordingly, a vortex line in the superconductor supports localized gapless right-handed and left-handed fermions with the dispersion relations E=+/-vp_z (v is a parameter dependent velocity) and thus propagating in opposite directions along the vortex line. However, the presence of the fermion mass immediately opens up a mass gap for such localized fermions and the dispersion relations become E=+/-v(m^2+p_z^2)^(1/2). When the pairing gap is parity odd, the situation is qualitatively different. The right-handed and left-handed sectors of the free space Hamiltonian in the ...

  11. Modified entropic gravitation in superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Matos, Clovis Jacinto de, E-mail: clovis.de.matos@esa.int [European Space Agency, 8-10 rue Mario Nikis, 75015 Paris (France)

    2012-01-15

    Verlinde recently developed a theoretical account of gravitation in terms of an entropic force. The central element in Verlinde's derivation is information and its relation with entropy through the holographic principle. The application of this approach to the case of superconductors requires to take into account that information associated with superconductor's quantum vacuum energy is not stored on Planck size surface elements, but in four volume cells with Planck-Einstein size. This has profound consequences on the type of gravitational force generated by the quantum vacuum condensate in superconductors, which is closely related with the cosmological repulsive acceleration responsible for the accelerated expansion of the Universe. Remarkably this new gravitational type force depends on the level of breaking of the weak equivalence principle for cooper pairs in a given superconducting material, which was previously derived by the author starting from similar principles. It is also shown that this new gravitational force can be interpreted as a surface force. The experimental detection of this new repulsive gravitational-type force appears to be challenging.

  12. Fault current limiters using superconductors

    Science.gov (United States)

    Norris, W. T.; Power, A.

    Fault current limiters on power systems are to reduce damage by heating and electromechanical forces, to alleviate duty on switchgear used to clear the fault, and to mitigate disturbance to unfaulted parts of the system. A basic scheme involves a super-resistor which is a superconductor being driven to high resistance when fault current flows either when current is high during a cycle of a.c. or, if the temperature of the superconductive material rises, for the full cycle. Current may be commuted from superconductor to an impedance in parallel, thus reducing the energy dispersed at low temperature and saving refrigeration. In a super-shorted transformer the ambient temperature primary carries the power system current; the superconductive secondary goes to a resistive condition when excessive currents flow in the primary. A super-transformer has the advantage of not needing current leads from high temperature to low temperature; it behaves as a parallel super-resistor and inductor. The supertransductor with a superconductive d.c. bias winding is large and has small effect on the rate of fall of current at current zero; it does little to alleviate duty on switchgear but does reduce heating and electromechanical forces. It is fully active after a fault has been cleared. Other schemes depend on rapid recooling of the superconductor to achieve this.

  13. Permanent magnets composed of high temperature superconductors

    Science.gov (United States)

    Weinstein, Roy; Chen, In-Gann; Liu, Jay; Lau, Kwong

    1991-01-01

    A study of persistent, trapped magnetic field has been pursued with high-temperature superconducting (HTS) materials. The main effort is to study the feasibility of utilization of HTS to fabricate magnets for various devices. The trapped field, when not in saturation, is proportional to the applied field. Thus, it should be possible to replicate complicated field configurations with melt-textured YBa2Cu3O7 (MT-Y123) material, bypassing the need for HTS wires. Presently, materials have been developed from which magnets of 1.5 T, at 77 K, can be fabricated. Much higher field is available at lower operating temperature. Stability of a few percent per year is readily attainable. Results of studies on prototype motors and minimagnets are reported.

  14. Two-dimensional superconductors with atomic-scale thickness

    Science.gov (United States)

    Uchihashi, Takashi

    2017-01-01

    Recent progress in two-dimensional superconductors with atomic-scale thickness is reviewed mainly from the experimental point of view. The superconducting systems treated here involve a variety of materials and forms: elemental metal ultrathin films and atomic layers on semiconductor surfaces; interfaces and superlattices of heterostructures made of cuprates, perovskite oxides, and rare-earth metal heavy-fermion compounds; interfaces of electric-double-layer transistors; graphene and atomic sheets of transition metal dichalcogenide; iron selenide and organic conductors on oxide and metal surfaces, respectively. Unique phenomena arising from the ultimate two dimensionality of the system and the physics behind them are discussed.

  15. Electromagnetic Dark Energy and Gravitoelectrodynamics of Superconductors

    CERN Document Server

    de Matos, Clovis Jacinto

    2007-01-01

    It is shown that Beck's electromagnetic model of dark energy in superconductors can account for the gravitomagnetic London moment, which has been conjectured by the author to explain the Cooper pair's mass excess reported by Cabrera and Tate. A new Einstein-Planck regime for gravitation in condensed matter is proposed as a natural scale to host the gravitoelectrodynamic properties of superconductors.

  16. Gravitational force between two electrons in superconductors

    CERN Document Server

    de Matos, Clovis Jacinto

    2007-01-01

    The attractive gravitational force between two electrons in superconductors is deduced from the Eddington-Dirac large number relation, together with Beck and Mackey electromagnetic model of vacuum energy in superconductors. This force is estimated to be weaker than the gravitational attraction between two electrons in the vacuum.

  17. High temperature superconductors: A technological revolution

    Science.gov (United States)

    1990-01-01

    The objectives are to demonstrate the Meissner effect through magnetic levitation, to demonstrate one application of the Meissner effect, the low friction magnetic rotation bearing, and to demonstrate magnetic flux penetration and the Type II nature of ceramic superconductors via the stacking of the superconductor disks. Experimental equipment and procedures are described.

  18. New Methods for Thin Film Deposition and First Investigations of the use of High Temperature Superconductors for Thin Film Cavities

    CERN Document Server

    Gustafsson, Anna; Vollenberg, Wilhelmus; Seviour, Rebecca

    2010-01-01

    Niobium thin film cavities have shown good and reliable performance for LEP and LHC, although there are limitations to overcome if this technique should be used for new accelerators such as the ILC. New coating techniques like High Power Impulse Magnetron Sputtering (HiPIMS) has shown very promising results and we will report on its possible improvements for Nb thin film cavity performance. Current materials used in accelerator Superconducting Radio Frequency (SRF) technologies operate at temperatures below 4 K, which require complex cryogenic systems. Researchers have investigated the use of High Temperature Superconductors (HTS) to form RF cavities, with limited success. We propose a new approach to achieve a high-temperature SRF cavity based on the superconducting ’proximity effect’. The superconducting proximity effect is the effect through which a superconducting material in close proximity to a non-superconducting material induces a superconducting condensate in the latter. Using this effect we hope...

  19. Modelling and comparison of trapped fields in (RE)BCO bulk superconductors for activation using pulsed field magnetization

    Science.gov (United States)

    Ainslie, M. D.; Fujishiro, H.; Ujiie, T.; Zou, J.; Dennis, A. R.; Shi, Y.-H.; Cardwell, D. A.

    2014-06-01

    The ability to generate a permanent, stable magnetic field unsupported by an electromotive force is fundamental to a variety of engineering applications. Bulk high temperature superconducting (HTS) materials can trap magnetic fields of magnitude over ten times higher than the maximum field produced by conventional magnets, which is limited practically to rather less than 2 T. In this paper, two large c-axis oriented, single-grain YBCO and GdBCO bulk superconductors are magnetized by the pulsed field magnetization (PFM) technique at temperatures of 40 and 65 K and the characteristics of the resulting trapped field profile are investigated with a view of magnetizing such samples as trapped field magnets (TFMs) in situ inside a trapped flux-type superconducting electric machine. A comparison is made between the temperatures at which the pulsed magnetic field is applied and the results have strong implications for the optimum operating temperature for TFMs in trapped flux-type superconducting electric machines. The effects of inhomogeneities, which occur during the growth process of single-grain bulk superconductors, on the trapped field and maximum temperature rise in the sample are modelled numerically using a 3D finite-element model based on the H-formulation and implemented in Comsol Multiphysics 4.3a. The results agree qualitatively with the observed experimental results, in that inhomogeneities act to distort the trapped field profile and reduce the magnitude of the trapped field due to localized heating within the sample and preferential movement and pinning of flux lines around the growth section regions (GSRs) and growth sector boundaries (GSBs), respectively. The modelling framework will allow further investigation of various inhomogeneities that arise during the processing of (RE)BCO bulk superconductors, including inhomogeneous Jc distributions and the presence of current-limiting grain boundaries and cracks, and it can be used to assist optimization of

  20. Ubiquitous signatures of nematic quantum criticality in optimally doped Fe-based superconductors.

    Science.gov (United States)

    Kuo, Hsueh-Hui; Chu, Jiun-Haw; Palmstrom, Johanna C; Kivelson, Steven A; Fisher, Ian R

    2016-05-20

    A key actor in the conventional theory of superconductivity is the induced interaction between electrons mediated by the exchange of virtual collective fluctuations (phonons in the case of conventional s-wave superconductors). Other collective modes that can play the same role, especially spin fluctuations, have been widely discussed in the context of high-temperature and heavy Fermion superconductors. The strength of such collective fluctuations is measured by the associated susceptibility. Here we use differential elastoresistance measurements from five optimally doped iron-based superconductors to show that divergent nematic susceptibility appears to be a generic feature in the optimal doping regime of these materials. This observation motivates consideration of the effects of nematic fluctuations on the superconducting pairing interaction in this family of compounds and possibly beyond.