Tesis sobre el tema "High critical temperature superconductor"
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Alméras, Philippe. "Photoemission spectroscopy on high critical temperature superconductors /". [S.l.] : [s.n.], 1995. http://library.epfl.ch/theses/?nr=1334.
Texto completoDurrell, John H. "Critical current anisotropy in high temperature superconductors". Thesis, University of Cambridge, 2001. https://www.repository.cam.ac.uk/handle/1810/34606.
Texto completoJones, Anthony Roger. "Critical currents in granular high temperature superconductors". Thesis, University of Cambridge, 1995. https://www.repository.cam.ac.uk/handle/1810/254043.
Texto completo郭明遠 y Ming-yuen Edward Kwok. "Numerical study of an isolated vortex and the lower critical field of a type-II superconductor in the presence of a twin plane". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31213169.
Texto completoKwok, Ming-yuen Edward. "Numerical study of an isolated vortex and the lower critical field of a type-II superconductor in the presence of a twin plane /". Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19670151.
Texto completoSchönborg, Niclas. "Development of loss models for a high-temperature superconducting tape". Doctoral thesis, KTH, Electrical Systems, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3268.
Texto completoIn the recent years significant progresses in thedevelopment of high-temperature superconductors have been made.It is realistic to believe that power applications, based onthese conductors, in a few years will become available. To beable to utilise the conductors in an optimum way, theunderstanding of their behaviour under application-likecondition is essential. One important parameter that has to beoptimised is the power loss, which means that mathematicalmodels of these losses have to be developed. In a typicalapplication the superconductor is utilised in a coilconfiguration where the actual magnetic field is considerablehigher than for a straight structure. For power frequencies thelosses are dominated by hysteresis losses and flux flowlosses.
In this thesis, mathematical models of the hysteresis andthe flux flow losses as a function of a transport current, anexternal magnetic field, the temperature and the frequency havebeen developed. The transport current and the magnetic field,which are assumed to be proportional to each other, includeboth an ac and a dc component. The models of the hysteresislosses are based on the critical state theory, and for twoidealised geometries, an infinite slab and a thin strip, newexact closed form equations have been derived. The equationsfor the two idealised geometries are then superimposed tofacilitate the description of a more realistic geometry, i.e. asuperconducting tape with a finite width and thickness. Themodel of the flux flow losses is valid for a tape shapedconductor and is based on both measurements and reasonablephysical assumptions. For the development and the validation ofthe models, a calorimetric measurement set-up has been used.From a limited number of relatively simple measurements, thedeveloped models can be adjusted to a certain superconductor,and the power losses for the actual superconductor can bepredicted in considerable more complicated cases.
Keywords:high-temperature superconductor, hysteresislosses, flux flow losses, critical state model, calorimetricmeasurements
Li, Aihua. "A study of the fabrication and characterisation of high temperature superconductor YBa₂Cu₃O₇ thin films". Access electronically, 2006. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20060928.143000/index.html.
Texto completoMcGordon, Andrew. "The current-voltage and noise properties of high temperature superconductor SNS and grain boundary junctions". Thesis, University of Birmingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368415.
Texto completoPutzke, Carsten Matthias. "Fermi surface and quantum critical phenomena of high-temperature superconductors". Thesis, University of Bristol, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.680124.
Texto completoRichens, P. E. "High temperature superconductors in electromagnetic applications". Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365792.
Texto completoGhazanfari, Nader. "Effects Of Nb2o5 Addition On The Formation And Properties Of Bi-based Superconductors". Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607468/index.pdf.
Texto completoLalonde, Richard. "Flux line interactions in conventional and high critical transition temperature superconductors". Thesis, University of Ottawa (Canada), 1990. http://hdl.handle.net/10393/6031.
Texto completoMcDowell, John Christopher. "Preparation characterisation and stability of selected high critical temperature ceramic superconductors". Thesis, University of Ulster, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260854.
Texto completoYang, Yifeng. "Studies on aspects of the critical current in high temperature superconductors". Thesis, University of Southampton, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315086.
Texto completoEverett, John. "Dissipation in high temperature superconducting tapes". Thesis, Imperial College London, 1998. http://hdl.handle.net/10044/1/8576.
Texto completoXu, Ming. "Critical current density and time-dependent magnetization of the high transition temperature superconductors". Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/30033.
Texto completoShin, Jae-Kyoung. "Mechanical Behavior and Its Relation to Superconducting Property of High Temperature Composite Superconductors". 京都大学 (Kyoto University), 2008. http://hdl.handle.net/2433/66211.
Texto completo0048
新制・課程博士
博士(工学)
甲第14163号
工博第2997号
新制||工||1445(附属図書館)
26469
UT51-2008-N480
京都大学大学院工学研究科材料工学専攻
(主査)教授 落合 庄治郎, 教授 河合 潤, 准教授 奥田 浩司
学位規則第4条第1項該当
Gandolfini, Germain. "Comparison of flux line cutting behaviour in high critical temperature and conventional Type II superconductors". Thesis, University of Ottawa (Canada), 1990. http://hdl.handle.net/10393/5757.
Texto completoHamid, Hamidi A. "The effect of strain and temperature on the critical current density of high-field superconductors". Thesis, Durham University, 1997. http://etheses.dur.ac.uk/5078/.
Texto completoCiceron, Jérémie. "Superconducting magnetic energy storage with second-generation high temperature superconductors". Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT012/document.
Texto completoMagnetic energy is stored when a superconducting inductance is fed with current. This principle is called SMES (Superconducting Magnetic Energy Storage). This kind of device has a relatively low energy density but can have a high power density. This PhD work has been conducted in the frame of the BOSSE project with the objective to develop a SMES demonstrator in the MJ range. This SMES will be especially compact and will reach a specific energy of 20 kJ/kg of winding, which is 50 % over the current world record for a superconducting coil. This performance is made possible by the use of 2nd generation high critical temperature superconductors, so-called “REBCO” conductors.This work tackles the general problematic of SMES design and proposes elements of reflection and solutions for fast pre-design of a SMES winding. The design of the high specific energy SMES of the BOSSE project is presented in detail.Modular elements (pancakes of REBCO tapes) of the SMES have been manufactured and tested in self-field and under background magnetic field. During these tests, transitions from superconducting state to normal state have been detected. These early detections have prevented the pancakes to be damaged when transitions occurred, even at very high current density (980 A/mm2 in the bare conductor). The measurement method is presented, as well as the results of the tests.The BOSSE project has been funded by the DGA (French Defence Procurement Agency)
Pei, Ruilin. "Measurement and analysis of critical current and AC loss of HTS tapes in a superconducting machine". Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609019.
Texto completoLópez, Bermúdez Juan Santiago [Verfasser]. "Correlation between Critical Magnetic Fields and Carrier Distance in High Temperature Superconductors / Juan Santiago López Bermúdez". München : Verlag Dr. Hut, 2014. http://d-nb.info/1058285432/34.
Texto completoEspinosa, Arronte Beatriz. "Resistivity and the solid-to-liquid transition in high-temperature superconductors". Doctoral thesis, KTH, Microelectronics and Applied Physics, MAP, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4251.
Texto completoIn high-temperature superconductors a large region of the magnetic phase diagram is occupied by a vortex phase that displays a number of exciting phenomena. At low temperatures, vortices form a truly superconducting solid phase which at high temperatures turns into a dissipative vortex liquid. The character of the transition between these two phases depends on the amount and type of disorder present in the system. For weak point disorder the vortex solid-to-liquid transition is a first-order melting. In the presence of strong point disorder the solid is thought to be a vortex-glass and the transition into the liquid is instead of second order. When the disorder is correlated, like twin boundaries or artificially introduced columnar defects, the transition is also second order, but has essentially different properties. In this work, the transition between the solid and liquid phases of the vortex state has been studied by resistive transport measurements in mainly YBa2Cu3O7-[delta](YBCO) single crystals with different types of disorder.
The vortex-glass transition has been investigated in an extended model for the vortex-liquid resistivity close to the transition that takes into account both the temperature and magnetic field dependence of the transition line. The resistivity of samples with different properties was measured with various contact configurations at several magnetic fields and analyzed within this model. For each sample, attempts were made to scale the transition curves to one curve according to a suitable scaling variable predicted by the model. Good scaling was found in a number of different situations. The influence of increasing anisotropy and angular dependence of the magnetic field in the model were also considered.
The vortex solid-to-liquid transition was also studied in heavy-ion irradiated YBCO single crystals. The ions create columnar defects in the sample that act as correlated disorder. A magnetic field was applied at a tilt angle with respect to the direction of the columns. At the transition the resistance disappears as a power law with different exponents in the three orthogonal directions considered. This provides evidence for a new type of critical behavior with fully anisotropic critical scaling properties not previously found in any physical system.
The effect on the vortex solid-to-liquid transition of high magnetic fields applied parallel to the superconducting layers of underdoped YBCO single crystals was also studied. Some novel features were observed: a sharp kink appearing close to Tc at high magnetic fields and a triple dip in the angular dependence of the resistivity close to B||ab in some regions of the phase diagram.
I högtemperatursupraledare består en stor del av det magnetiska fasdiagrammet av en vortexfas som uppvisar ett flertal spännande fenomen. Vid låga temperaturer bildar vortexarna en fast vortexfas utan elektriskt motstånd. Vid högre temperatur övergår denna fas till en dissipativ vortexvätska. Egenskaperna hos denna fasövergång beror på oordningen i form av defekter. Vid svag punktoordning är fasomvandlingen mellan det fasta och flytande vortextillståndet en första ordningens smältövergång. Vid stark punktoordning anses den fasta fasen vara ett vortexglas och övergången till vortexvätskan är istället av andra ordningen. När oordningen är korrelerad, som för tvillinggränser eller artificiellt skapade kolumndefekter, är övergången också av andra ordningen men med väsentligt annorlunda egenskaper. I detta arbete har övergången mellan det fasta och det flytande vortextillståndet studerats med resistiva transportmätningar i framförallt enkristaller av YBa2Cu3O7-[delta] (YBCO) med olika typer av oordning.
Vortexglasövergången har undersökts i en utvidgad modell för resistansen i vortexvätskan nära fasövergången där hänsyn tas till såväl temperatur- som fältberoendet. Resistansen hos prover med olika egenskaper mättes i varierande magnetfält och i flera kontaktkonfigurationer och analyserades inom denna modell. Övergångskurvorna skalades till en kurva med en skalningsvariabel som givits av modellen. God skalning uppnåddes i flera olika fall. Effekten av ökande anisotropi och vinkelberoendet i modellen undersöktes också.
Vortexövergången mellan det fasta och det flytande vortextillståndet undersöktes även i enkristaller av YBCO bestrålade med tunga joner. Jonerna skapade kolumndefekter som fungerar som korrelerad oordning. Vinkeln mellan pålagt magnetfält och dessa kolumndefekter varierades. Vid fasövergången avtar resistansen som en potenslag med olika exponenter i de tre undersökta ortogonala riktningarna. Detta ger experimentell belägg för en ny typ av kritiskt beteende med fullständigt anisotropa kritiska skalningsegenskaper.
Egenskaparna hos på vortexövergången mellan fast och flytande fas vid höga magnetfält parallella med de supraledande lagren hos underdopade YBCO enkristaller undersöktes också. Några nya effekter observerades: en skarp knyck uppstod nära Tc vid höga magnetfält och en tredubbel dipp i den vinkelberoende resistiviteten nära B||ab i några regioner av fasdiagrammet.
Al-Mosawi, Maitham Khazal. "The fabrication and characterisation of High Temperature Superconducting tapes and coils". Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287318.
Texto completoNyhus, Jørgen. "Resonant Ultrasonic System Design, and Measurements of Critical Behaviour and Flux-Line Elasticity in High Temperature Superconductors". Doctoral thesis, Norwegian University of Science and Technology, Department of Physics, 2001. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-2117.
Texto completoTesta, Joseph Anthony. "Experimental studies of 1/f noise in high-critical-temperature superconductors in the normal and superconducting states /". The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487587604133792.
Texto completoFriend, Christopher Michael. "Transport critical current density measurements on high and low temperature superconductors in magnetic fields up to 15 tesla". Thesis, Durham University, 1994. http://etheses.dur.ac.uk/5827/.
Texto completoMilliken, Damion Alexander. "Uranium doping of silver sheathed bismuth-strontium-calcium-copper-oxide superconducting tapes for increased critical current density through enhanced flux pinning". Access electronically, 2004. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20040810.154223/index.html.
Texto completoSaleh, Paul Matthew. "Characterisation of practical high temperature superconductors in pulsed magnetic fields and development of associated technology". Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365786.
Texto completoYuan, Weijia. "Second-generation high-temperature superconducting coils and their applications for energy storage". Thesis, University of Cambridge, 2010. https://www.repository.cam.ac.uk/handle/1810/229754.
Texto completoGhorbani, Shaban Reza. "Structural and Electrical Transport Properties of Doped Nd-123 Superconductors". Doctoral thesis, KTH, Physics, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3461.
Texto completoIt is generally believed that one of the key parameterscontrolling the normal state and superconducting properties ofhigh temperature superconductors is the charge carrierconcentrationpin the CuO2planes.By changing the non-isovalent dopingconcentration on the RE site as well as the oxygen content in(RE)Ba2Cu3O7−δ, an excellent tool is obtained tovary the hole concentration over a wide range from theunderdoped up to the overdoped regime.In the present thesis thefocus is on the doping effects on the structural and normalstate electrical properties in Nd-123 doped with Ca, La, Pr,Ca-Pr, and Ca-Th.T he effects of doping have been investigatedby X-ray and neutron powder diffraction, and by measurements ofthe resistivity, thermoelectric powerS, and Hall coefficient RH.T he thermoelectric power is a powerful tool forstudies of high temperature superconductivity and is highlysensitive to details of the electronic band structure.Sas a function of temperature has been analyzed in twodifferent two band models.The parameters of these models arerelated to charactristic features of the electron bands and asemiempirical physical description of the doping dependence ofSis obtained.So me important results are following:
(i)The valence of Pr in the RE-123 family.Results from thestructural investigations, the critical temperature Tc, and thethermoelectric power indicated a valence +4 at low dopingconcentration, which is in agreement with results of chargeneutral doping in the RE-123 family.(ii)Hole localization. The results of bond valence sum (BVS)calculations from neutron diffraction data showed that holelocalization on the Pr+4site was the main reason for the decrease of thehole concentration p.Differ ent types of localization wereinferred by S measurements for Ca-Th and Ca-Pr dopings.(iii)Competition between added charge and disorder. Theresults of RH measurements indicated that Ca doping introduceddisorder in the CuO2planes in addition to added charge.This could bethe main reason for the observed small decrease of thebandwidth of the density of states in the description of aphenomenological narrow band model.(iv) Empirical parabolic relation between γ and p.S data were analyzed and well described by a two-band modelwith an additional linear T term, γT.An empiricalparabolic relation for γ as a function of holeconcentration has been found.
Key words:high temperature superconductors, criticaltemperature, resistivity, thermoelectric power, Hallcoefficient, X-ray diffraction, Neutron diffraction, NdBa2Cu3O7−δ, hole concentration,substitution.
Lanckbeen, Alain. "Study of physico-chemical and physical properties of the high critical temperature superconductor YBa2Cu3O7-d in relation to the substitution of copper by zinc or iron and the oxygen stoichiometry". Doctoral thesis, Universite Libre de Bruxelles, 1994. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212699.
Texto completoDuncan, Fiona Hazel. "Characterisation of superconducting Nd123 solid solutions and related phases". Thesis, University of Aberdeen, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297558.
Texto completoIliescu, Adriana Simona. "Superconducting joints of melt-textured YBCO monoliths: preparation, microstructure and critical currents". Doctoral thesis, Universitat Autònoma de Barcelona, 2004. http://hdl.handle.net/10803/3359.
Texto completoEl primer paso en obtener soldaduras superconductoras de alta temperatura del material YBCO ha sido el de conseguir un agente soldante apropiado. Hemos investigado dos materiales basados en plata como agentes soldantes: polvo de óxido de plata y una lamina de plata metálica. Análisis microestructural, junto con medidas de magnetorresistencia y magnetometria Hall se han realizado con el fin de encontrar las condiciones óptimas para conseguir soldaduras superconductoras de alta temperatura de alta calidad.
Para entender el proceso de difusión de la plata en la matriz YBCO, se ha realizado un detallado estudio de la influencia de los parámetros del proceso de la soldadura en la microestructura y las propiedades físicas de las uniones superconductoras, es decir la magnetización remanente y la densidad de corriente critica, generadas mediante este método. Se ha demostrado que estos parámetros influyen tanto en la microestructura como en las propiedades superconductoras de las uniones artificiales. Para optimizar estos parámetros se han realizado dos tipos de experimentos: enfriamiento muy rápido y crecimiento mediante enfriamiento lento. Utilizando los experimentos de enfriamiento muy rápido hemos conseguido determinar cuales son los parámetros que controlan la difusión de la plata en la matriz del material YBCO. Se ha demostrado que parámetros como: tiempo del fundido, el grosor de la lámina de plata y la configuración de la soldadura son relevenates y han sido optimizados. Por otro lado, la influencia de parámetros como: la velocidad de enfriamiento, temperatura máxima del proceso de la soldadura y la ventana de temperaturas en la microestructura de las uniones artificiales se han analizado mediante experimentos de enfriamiento lento.
La influencia de estos parámetros en las propiedades superconductoras de las soldaduras se ha estudiado a través de medidas de magnetización remanente de las uniones y del material YBCO, a la vez para su comparación. La distribución de la magnetización remanente ha sido investigada utilizando magnetometria Hall. Estas medidas nos han permitido deducir la magnitud de la densidad de corriente crítica resolviendo el problema inverso (ley Biot-Savart).
Utilizando la metodología desarrollada en este trabajo hemos conseguido obtener uniones artificiales del material YBCO cuyas microestructuras y propiedades superconductoras tienen una calidad similar a las del material inicial YBCO y por lo tanto se ha desarrollado una metodología que permitirá obtener ceramicas superconductoras con dimensiones mayores y formas complejas.
The final goal of this PhD thesis was to obtain YBa2Cu3O7- (YBCO) samples with different geometries and bigger dimensions than those obtained by the crystalline growth techniques. These materials can be integrated in electrical machinery, levitating devices or fault current limiter systems. This need has driven the investigation to welding techniques that can joint two or more YBa2Cu3O7- single-domains by a solidification process using welding agents whose melting points are below the melting point of YBa2Cu3O7- material.
The first step in achieving high temperature superconducting YBCO joints was to find a suitable welding material. We have investigated two Ag based materials as welding agents: Ag2O powder and Ag thin foil. Microstructural analysis along with magnetoresistance and in-field Hall mapping measurements have been performed to find the conditions to reach a high quality superconducting joints.
A deep study of the influence of different parameters on the microstructure and on the superconducting properties of the final joints, i.e. remanent magnetization and critical current density of the final joints, generated using a YBCO/Ag/YBCO architecture has been performed in order to understand the role of the Ag diffusion and to optimize the welding process. It has been shown that these parameters influence in one way or another the microstructure and superconducting properties of the final joints. In order to optimize these parameters, we have performed two kinds of experiments: quench experiments and slow cooling experiments. By quench experiments we have succeed in controlling the Ag diffusion process into the YBCO matrix. Parameters such as: melting time, Ag foil thickness and weld configuration have been investigated and optimized. On the other hand, the influence of parameters such as: cooling rate, processing temperature and window temperature, on the microstructure of the final joints has been analyzed by slow cooling experiments.
The influence of welding parameters on the superconducting properties of the final joints has been studied by determining the remanent magnetization profiles of each sample and calculating from them the critical current density of the joints and YBCO grains for comparison. The remanent magnetization distribution on samples joint by the welding process was investigated by using a Hall probe imaging system. These measurements allowed us to deduce the magnitude of the critical current densities by solving the inverse problem, as well as the homogeneity and spatial scale on which they flow.
We have proposed a methodology in order to determine the critical current density from the results obtained after solving the inverse problem. We have observed that the current distribution pattern obtained from this methodology agrees well with current distribution profile predicted by Bean model.
In summary, by employing the new welding methodology developed in the present work, we have been able to obtain YBCO superconducting joints having a clean and crystallographic coincident microstructure and with critical current densities through the joint similar to those of the YBCO monoliths.
Sneary, Adrian Bernard. "The fabrication of a high temperature superconducting magnet and critical current characterisation of the component Bi₂Sr₂Ca₂Cu₃Oₓ tapes and filaments in high magnetic fields". Thesis, Durham University, 2000. http://etheses.dur.ac.uk/4517/.
Texto completoKeys, Simon Alastair. "Temperature and strain scaling laws for the critical current density in Nb(_3)Sn and Nb(_3)Al conductors in high magnetic fields". Thesis, Durham University, 2001. http://etheses.dur.ac.uk/3951/.
Texto completoChouial, Baghdadi. "Investigation of superconductor tunnel junctions on YBCO high temperature superconductor". Thesis, University of Bath, 1991. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303029.
Texto completoSeverac, Childerick Henri Louis. "Spin injection into high temperature superconductor". Thesis, University of Birmingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369295.
Texto completoHuang, Taotao. "Quench modelling of high temperature superconductor". Thesis, University of Southampton, 2006. https://eprints.soton.ac.uk/65717/.
Texto completoMcDonald, Peter Hughes 1965. "High temperature superconductor thin film optical detectors". Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277167.
Texto completoLecrevisse, Thibault. "Contribution à l'étude des aimants supraconducteurs utilisant des matériaux supraconducteurs à haute température de transition". Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00875176.
Texto completoDorget, Rémi. "Étude et conception d'une machine supraconductrice à modulation de flux pour application aéronautique". Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0018.
Texto completoAs part of the fight against climate change, the aeronautics industry has set itself the goal of becoming totally carbon neutral by 2050. To achieve this, the use of disruptive technologies is necessary to reduce the emissions of this fast-growing sector. Among these technologies, we find electrification, but its deployment requires high specific power electrical machines. In this context, superconductivity can be a way of improving electrical machines thanks to the high current densities and intense magnetic fields that can be generated with superconducting materials. The main drawback of this technology is the need to operate at cryogenic temperatures. However, the prospect of aircraft using liquid hydrogen as a fuel, transported at -253°C, presents a synergy with superconductivity. It is in this context that the work of this thesis is placed, which aims to study the use of high critical temperature superconducting materials for the development of a high specific power superconducting engine employing an original topology called "flux modulation machine". This machine structure has been studied for several years at the University of Lorraine within the Groupe de Recherche en Énergie Électrique de Nancy (GREEN), the laboratory in which this thesis was carried out. The work reported in this manuscript is part of a CIFRE agreement with the company SAFRAN. In order to allow the study of this machine, this thesis includes two chapters dedicated to the semi-analytical electromagnetic modelling of an axial flux modulation machine. The objective of this model is to allow a fast and accurate calculation of the torque and losses of a machine. The use of this model in the following chapter leads to the electromagnetic dimensioning of a 260 kW demonstrator. This design also takes into account the various technical and logistical constraints encountered. A fifth chapter details the ongoing construction of the demonstrator and its mechanical and cryogenic structure. Finally, the last chapter of this manuscript deals with the extrapolation of the experimental results in order to evaluate the potential performances of flux modulation machines at higher power
James, M. P. "Deformation mechanisms for the high temperature Bi-2223 superconductor". Thesis, University of Cambridge, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.605023.
Texto completoZentile, Catherine Lucy. "Transport studies of two classes of high temperature superconductor". Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609066.
Texto completoStyles, Iain Bruce. "One hole in a high temperature superconductor : Fermi liquid?" Thesis, University of Birmingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275708.
Texto completoPerconte, David. "Proximity effect between a high temperature superconductor and graphene". Electronic Thesis or Diss., Sorbonne université, 2018. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2018SORUS119.pdf.
Texto completoWe have fabricated YBCO graphene junction. We studied the electronical transport at the interface between these two materials as well as the mechanism - the Andreev reflexion- by which a current carried by electrons is transformed into a current carried by Cooper pairs. We observed electronic interferences as a function of graphene doping. This modulation comes from the presence of a potential barrier at the interface between YBCO and graphene in which the particles are circulating before being transmitted or reflected. These interferences correspond to Klein tunneling of normal electrons when their energy is higher than the superconducting gap. At lower energy, Cooper pairs can traverse the barrier by Klein tunneling. We later fabricated YBCO graphene junctions which size is comparable to the graphene coherence length. We observed tunnel conductance when the interface between graphene and YBCO is opaque. In the case when the interface is transparent, we observed oscillations of the junction conductance as a function of the bias voltage and of the gate voltage. These oscillations seem to originate from electronic interferences inside the graphene channel between the superconducting electrodes. We also propose an experimental method to fabricate phi junction based on BSCCO
Freitas, Rafael Cassiolato de. "Limitador de corrente eletrica monofasico resistivo supercondutor de alta temperatura critica". [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259009.
Texto completoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: O crescimento da demanda de energia elétrica nos centros urbanos e industriais tem levado à necessidade de expansão dos sistemas de energia elétrica o que tem causado aumento nos níveis de curto-circuito, atingindo o limite da capacidade dos sistemas de proteção existentes exigindo sua substituição por outros de maior capacidade. Nessa situação nem sempre a recapacitação dos sistemas de proteção resolve o problema sendo necessário duplicar circuitos. Para postergar investimentos ou para funcionar na rede juntamente com o disjuntor ou ainda, para proteger os circuitos existentes quando conectados a geradores distribuídos, os limitadores de corrente instalados em série com os disjuntores atuais permitem limitar a corrente de falta, principalmente nos primeiros 100ms até a atuação do sistema de proteção. Dentre os diversos tipos de dispositivos limitadores de corrente elétrica existentes no mercado e também ainda em pesquisa atualmente, os construídos a partir de materiais supercondutores possuem a vantagem de proporcionar limitação de corrente elétrica praticamente instantânea causando mínima interferência no funcionamento normal dos sistemas de energia elétrica. Neste trabalho foram estudadas diversas configurações de limitadores de corrente elétrica utilizando fitas de materiais cerâmicos supercondutores de alta temperatura crítica (HTS), de modo especial os limitadores resistivos em forma de bobinas helicoidais enroladas com fita supercondutora BSCCO. Foi desenvolvida metodologia para o cálculo eletromagnético, projeto, construção e ensaio das bobinas supercondutoras do limitador de corrente, bem como se procurou caracterizar eletricamente a fita HTS sob influência de campo magnético externo com o objetivo de determinar as condições de corrente elétrica e de campo magnético sobre ela aplicado para a transição do estado supercondutor para o estado condutor normal do material ("quench"). Ao final do trabalho foram construídos e ensaiados dois protótipos limitadores de corrente elétrica supercondutores mostrando que, apesar da fita HTS de BSCCO ainda não possuir características adequadas para aplicação em limitadores de corrente, com a esperada evolução destes materiais já existe disponível a técnica para projetá-los e construí-los.
Abstract: The growth in demand of electric energy in urban and industrial centers has lead to the need of expansion of the electrical systems which has caused increase in short circuit levels, reaching the limit capacity of the existing protection systems requiring its replacement by others of greater capacity. In these situations the upgrade of protection systems does not always solve the problem being necessary the circuit's duplication. To postpone investments, to operate together in the electrical system with the circuit breakers or even to protect the existing circuits when connected to distributed generators, fault current limiters should be installed in series with the circuit breakers allowing to limit fault currents, specially in the first 100m until the protection system is triggered. Among the many different types of fault current limiter devices existing in the market and which are under development, the ones made of superconducting materials have the advantage of providing practically instantaneous fault current limitation causing minimum interference in the normal operation of the electrical systems. In this work many configurations of electric fault current limiters were studied using superconducting ceramic materials of high transition temperature (HTS), specially the resistive superconducting fault current limiters in form of helical coils with BSCCO superconducting tapes. The methodology for the electromagnetic calculation, project, construction and tests of the superconducting coils of the fault current limiter was carried out along with the HTS tape characterization under external magnetic field influence in order to determine the conditions of electric current and magnetic field for the transition from superconducting state to normal conducting state (quench). At the end of this work two fault current limiters were built and tested showing that, although BSCCO HTS tapes yet do not have good characteristics for fault current limiters application, when these materials which tend to be developed reach applicability level, the technique to design and built them is already available.
Mestrado
Energia Eletrica
Mestre em Engenharia Elétrica
Connors, Sean Mark. "Effects of high energy electron irradiation on a YBa_x001B_b2_x001B_sCu_x001B_b3_x001B_s0_x001B_b7_x001B_s- high temperature superconductor". Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/28145.
Texto completoRayner, Simon. "Positron annihilation studies of high temperature superconductors and related compounds". Thesis, University of East Anglia, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291668.
Texto completoShunmugavel, Karthikeyan. "Rapid single flux quantum logic in high temperature superconductor technology". Enschede : University of Twente [Host], 2006. http://doc.utwente.nl/57620.
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