Tesis sobre el tema "Superconducting bulks"
Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros
Consulte los 34 mejores tesis para su investigación sobre el tema "Superconducting bulks".
Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.
También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.
Explore tesis sobre una amplia variedad de disciplinas y organice su bibliografía correctamente.
Bozzo, Closas Bernat. "Superconducting joining of melt textured YBCO bulks". Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/369047.
Texto completoThe obtention of bulk YBa2Cu3O7 tiles by the Top Seeded Melt Growth method carries and implicit limitation on the shape and size of the pieces. In order to overcome this limitation a joining method based on the use of an Ag foil as a welding agent has been proposed. This thesis work was focused in the following aspects: • The refinement of the welding methodology for YBCO pellets in order to solve the issues present. • Characterization of the microstructure of welded pellets. • The development of suitable quantitative analysis tool for evaluating the weld quality in terms of its superconducting behavior. • The expansion of the methodology to include welds with crystallographic misorientation and study the influence of such a crystallographic misorientation on the electric and magnetic properties The first step was to develop a furnace bundled with an in-situ observation video setup that allowed visually record the evolution of the sample during the thermal process. Those videos revealed the existence of two types of liquids that were dragged out from the weld position. The microstructural study carried out on the welded samples indicated that this loss of liquid was the source of microstructural malformations at the weld position. A modification on the sample holder was required and solved the issue. All the studied samples were analyzed under the scope of their micro-structural characteristics and their magnetic properties. For the case of the micro-structural characterization, a basic study was carried out in order to determine the successfulness of the weld formation and it was used as a feedback parameter for fine-tuning the thermal process. The weld microstructure was further investigated in order to obtain more information about its characteristics and in order to obtain a better understanding about the mechanisms that make the weld formation possible. A proper study of the magnetic and electric properties was also required, since the final objective of the superconducting welding technology is to join several YBCO tiles while maintaining the superconducting properties at the weld position. For that purpose, magnetic imaging Hall Effect based measurements were performed on the specimens under study. From the local magnetization maps, current density distribution maps were obtained by using specialized software. In order to understand and obtain useful information from those current density maps, a simulation software piece was developed and the knowledge acquired from those simulations allowed obtaining the inter- and intra-granular critical current density values (JcGB and JcG) from each sample. The ratio between JcGB and JcG was studied as a function of the misorientation angle. In principle, a behavior similar to coated conductors was expected. However, the dependence found was weaker than the considered model case. That determined dependence was compared with similar studies on grain boundaries in bulk YBCO, revealing a similar behavior and indicating that the JcGB/JcG ratio value was potentially intrinsic to the misorientation angle. This hypothesis was confirmed when several samples with different YBCO grain characteristics but with the sample misorientation were compared. Field dependence measurements of the magnetization maps were also performed in order to determine the vortex pinning regimes present at the samples and to compare them with the thin film case. Despite the weld pinning regimes were similar, the behavior at the grain was slightly different. Finally, the superconducting properties were correlated with the mechanical properties. The hardness of the material was evaluated by using nano-indentation techniques at different positions. The ratio between the hardness at the weld and away from the weld exhibited a high correlation with the JcGB/JcG ratio.
Patel, Anup. "Pulsed field magnetization of composite superconducting bulks for magnetic bearing applications". Thesis, University of Cambridge, 2013. https://www.repository.cam.ac.uk/handle/1810/256579.
Texto completoYan, Yu. "Thermally actuated magnetisation flux pump system for high temperature superconducting bulks". Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609510.
Texto completoHuang, Zhen. "A fully high temperature superconducting synchronous motor using pulsed field magnetization, bulks, and 2G HTS coils". Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709396.
Texto completoSusner, Michael A. "Influences of Crystalline Anisotropy, Doping, Porosity, and Connectivity on the Critical Current Densities of Superconducting Magnesium Diboride Bulks, Wires, and Thin Films". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1344984007.
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
Grira, Sarra. "Microstructure, texture and superconductive properties of High Temperature Superconducting "HTS" oxides : yBCO thin films and bulk NBCO and YBCO". Thesis, Metz, 2009. http://www.theses.fr/2009METZ005S/document.
Texto completoThe aim of this work is the study of crystallographic texture and microstructure in connection with the superconducting properties (Tc and Jc) of High Temperature Superconducting (HTS) materials: YBCO and NBCO. Microstructure is studied by X-Ray Diffraction (XRD) and Electron backscatter Diffraction (EBSD). The Determination of critical temperature (Tc) and critical current density (Jc) are made with Superconducting Quantum Interference Device (SQUID) magnetometer or Physical Properties Measurement System (PPMS). The first part of this work investigates the crystallographic textures of the YBCO film by using EBSD in order to deduce the epitaxial relationship between the superconducting layer and the buffer layer. This thin film is made up of three successive deposits (among which 300 nm of YBCO), used in fault current limiters for electrical engineering applications. The second part presents the study of NdBa2Cu3O7-d (NBCO) and YBCO bulks prepared by various techniques. The effect of silver doping of YBCO has been studied on samples prepared by the Melt Textured Growth (MTG) technique under low oxygen partial pressure. The doping up to a given amount of silver enhances the microstructure and the critical current density. A comparison of the physical and structural characteristics between NBCO oxygenated exsitu and YBCO oxygenated in-situ, prepared by MTG under high magnetic field has been made. Zone-melted NBCO samples textured by zone melting method oxygenated respectively in-situ and ex-situ have been studied. These samples exhibit the same texture with the occurrence of twins for the NBCO oxygenated ex-situ
Kurupakorn, C., N. Hayakawa, N. Kashima, S. Nagaya, M. Noe, K. P. Juengst y H. Okubo. "Development of high temperature superconducting fault current limiting transformer (HT/sub c/-SFCLT) with Bi2212 bulk coil". IEEE, 2004. http://hdl.handle.net/2237/6750.
Texto completoManton, Stephen John. "Fabrication and characterisation of high temperature superconducting bulk YBCO". Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396128.
Texto completoShimizu, H., K. Kato, Y. Yokomizu, T. Matsumura y N. Murayama. "Resistance rise in Bi2223 superconducting bulk after normal transition due to overcurrent". IEEE, 2001. http://hdl.handle.net/2237/6782.
Texto completoZhao, Wen. "Improvement in the growth and superconducting properties of bulk Sm-Ba-Cu-O superconductors fabricated in air". Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/269923.
Texto completoKato, K., T. Noda, H. Shimizu, T. Matsumura y N. Murayama. "Increase in transient resistance of Bi2223 superconducting bulk by applying external magnetic field". IEEE, 2001. http://hdl.handle.net/2237/6784.
Texto completoYang, Yuan. "Influence of Chemical Doping on Microstructures and Superconducting Properties of MgB2 Wires and Bulk Samples". The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469187563.
Texto completoShimizu, H., Y. Yokomizu, T. Matsumura y N. Murayama. "Proposal of flux flow resistance type fault current limiter using Bi2223 high T/sub c/ superconducting bulk". IEEE, 2002. http://hdl.handle.net/2237/6785.
Texto completoSofie, Stephen W. "Processing of doped YBa₂Cu₃0₇₋x melt textured bulk single crystals for enhanced superconducting properties /". Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/10612.
Texto completoNorsworthy, Mark A. (Mark Andrew). "Characterization of ferromagnetic saturation at 4.2K of selected bulk rare earth metals for compact high-field superconducting cyclotrons". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62700.
Texto completoCataloged from PDF version of thesis.
Includes bibliographical references (p. 39).
The saturation magnetization of the rare earth ferromagnetic metals gadolinium and holmium was investigated. Cylindrical samples were placed in a superconducting test magnet and induced magnetic field measured at various applied fields. Data was obtained with Hall sensors mounted at the tips of the cylinders, and a powerful analytical calculation was derived to allow estimation of the saturation magnetization from this surface data. If the metal is saturated in a uniform, vertical magnetic field, the measured field at the surface due to the magnetization of the cylinder is just the saturation magnetization divided by a factor of two. Results show saturation magnetization values ranging from 0.5 to 1.5 T higher than iron, establishing the candidacy of these metals for advanced superconducting cyclotron pole tips.
by Mark A. Norsworthy.
S.M.and S.B.
Valente-Feliciano, Anne-Marie. "Development of SRF monolayer/multilayer thin film materials to increase the performance of SRF accelerating structures beyond bulk Nb". Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112254/document.
Texto completoThe minimization of cost and energy consumption of future particle accelerators, both large and small, depends upon the development of new materials for the active surfaces of superconducting RF (SRF) accelerating structures. SRF properties are inherently a surface phenomenon as the RF only penetrates the London penetration depth λ, typically between 20 and 400 nm depending on the material. When other technological processes are optimized, the fundamental limit to the maximum supportable RF field amplitude is understood to be the field at which the magnetic flux first penetrates into the surface, Hc₁. Niobium, the material most exploited for SRF accelerator applications, has Hc₁~170 mT, which yields a maximum accelerating gradient of less than 50 MV/m. The greatest potential for dramatic new performance capabilities lies with methods and materials which deliberately produce the sub-micron-thick critical surface layer in a controlled way. In this context, two avenues are pursued for the use of SRF thin films as single layer superconductor or multilayer Superconductor-Insulator-Superconductor structures: Niobium on copper (Nb/Cu) technology for superconducting cavities has proven over the years to be a viable alternative to bulk niobium. However the deposition techniques used for cavities, mainly magnetron sputtering, have not yielded, so far, SRF surfaces suitable for high field performance. High quality films can be grown using methods of energetic condensation, such as Electron Cyclotron Resonance (ECR) Nb ion source in UHV which produce higher flux of ions with controllable incident angle and kinetic energy. The relationship between growth conditions, film microstructure and RF performance is studied. Nb films with unprecedented “bulk-like” properties are produced. The second approach is based on the proposition that a Superconductor/Insulator/Superconductor (S-I-S) multilayer film structure deposited on an Nb surface can achieve performance in excess of that of bulk Nb. Although, many higher-Tc superconducting compounds have Hc₁ lower than niobium, thin films of such compounds with a thickness (d) less than the penetration depth can exhibit an increase of the parallel Hc₁ thus delaying vortex entry. This overlayer provides magnetic screening of the underlying Nb which can then remain in the Meissner state at fields much higher than in bulk Nb. A proof of concept is developed based on NbTiN and AlN thin films. The growth of NbTiN and AlN films is studied and NbTiN-based multilayer structures deposited on Nb surfaces are characterized. The results from this work provide insight for the pursuit of major reductions in both capital and operating costs associated with future particle accelerators across the spectrum from low footprint compact machines to energy frontier facilities
Lewin, Richard Peter. "Superconductors and high magnetic fields". Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:09992030-625d-4e6c-8152-6a61bb2cdb07.
Texto completoSilva, Jorge Manuel Marques. "Application of superconducting bulks and stacks of tapes in electrical machines". Master's thesis, 2015. http://hdl.handle.net/10362/15630.
Texto completoShih, Chia-Ming y 石家銘. "Superconducting properties of bulk MgB2". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/9f76ge.
Texto completo中原大學
應用物理研究所
91
For the preparation of good bulk MgB2, we first pressed the MgB2 powder into a pellet, heat treatment under high temperature and 1 atm Ar circulation was then proceeded. XRD was used to evaluate our post-treatment MgB2 pellet, and SQUID was used to measure its magnetic properties. Tc, Hc1(0), Hc2(0), ξ(0), λ(0), κ, the important superconducting parameters of the bulk, was then inferred from the measure data. Finally, using Beam model and ΔM of our hysteresis magnetization curves, the critical supercurrent density Jc could easily be determined. Our experimental results give us,for the bulk MgB2, Tc~ 39.4K,Hc1(0)~ 490 64, Hc2(0)~ 15 2 T , ξ(0)~ 4.7 0.3 nm , λ(0)~ 101 16 nm , κ~ 22 3. Besides, for the MgB2 bulk covered with Mg at 950℃, Jc(5K)~ 3.2×10^5A/cm2, which is higher than the conventional value of 1.0×10^4A/cm2.
Guan, Syu-You y 關旭佑. "Superconducting topological surface states in thenoncentrosymmetric bulk superconductor PbTaSe2". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/gx33b5.
Texto completo國立臺灣大學
物理學研究所
105
In this thesis, we first introduce the previous study of topological insulator and the topological superconductor. The discovery of topological insulator (TI) is a recent breakthrough of physics. The topological protect surface in TI, forbidden the backscattering of electrons, gives new transport properties of the material. Combining the superconductor with the topological properties may host a type of new material called topological superconductor (TSC). The search for TSCs is one of the most urgent contemporary problems in condensed matter systems. TSCs are characterized by a full superconducting gap in the bulk and topologically protected gapless surface (or edge) states. Within each vortex core of TSCs, there exist the zero-energy Majorana bound states, which are predicted to exhibit non-Abelian statistics and to form the basis of the fault-tolerant quantum computation. To date, no stoichiometric bulk material exhibits the required topological surface states (TSSs) at the Fermi level (EF) combined with fully gapped bulk superconductivity. In the second chapter, we introduce the construction of an ultra-low-temperature (ULT) high-magnetic-field (HF) ultra-high-vacuum (UHV) scanning tunneling microscope. Sub-Kelvin temperature and strong field advance the ability of instrument in research. UHV environment keeps cleanness of the sample during the study. Such instrument working in three extreme environments needs to state-of –the-art design with the careful operation. The test result shows the STM has high resolution in energy and space. In the third chapter, we report atomic-scale visualization of the TSSs of the noncentrosymmetric fully gapped superconductor PbTaSe2. Using quasi-particle scattering interference imaging, we find two TSSs with a Dirac point at E ≅ 1.0 eV, of which the inner TSS and the partial outer TSS cross EF on the Pb-terminated surface. With sub-Kelvin energy resolution achieved in the ULT-HF-UHV STM, the fully superconducting gap of PbTaSe2 is clearly resolved, which suggests the TSS gapped out at EF. The tunneling conductance map shows the vortex is presented under the magnetic field, and zero energy conductance peak is observed at vortex core. This discovery reveals PbTaSe2 as a promising candidate for TSC. Lastly, the future improvement of the instrument and further study for PbTaSe2 are introduced. Increasing the holding time at 4 K and investigate the pairing mechanism are priorities. Keyword: Topological superconductor, topological insulator, Majorana fermion, scanning tunneling microscope, PbTaSe2
Chu, Hwa Wei y 朱華偉. "Improvement of Superconducting Properties in NdBa2Cu3O7 Melt-Textured Bulk Superconductor". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/23386402947988976971.
Texto completo國立臺灣大學
化學工程學研究所
87
The object of this study is to improve the superconducting properties of the MTG 123 bulk. We found that the increasing dose of Nd422 could improve the Tc of Nd123 powder. The influence of oxygen partial pressure on Tc is large when the percentage of Nd422 in Nd123 is small. When the percentage of Nd422 is higher, the effect of pressure could be neglect. To the MTG Nd/Au bulk, the superconducting properties are very sensitive to oxygen partial pressure. First, the vacuum MTG process adopting 1 torr oxygen partial pressure could produce the bulk with higher Tc. Second, the low pressure heat treatment could really improve the superconducting properties. The reaction between Y123 and Nd422 produce Nd123 and Y211. For better crystal quality, the melting temperature of Nd123 has to be viewed as peritectic point in the Y123/Nd422 MTG process. The vacuum MTG process can also result in better superconducting properties. The Tc of samples produced under normal pressure could be enhanced by low pressure heat treatment.
Castillo, Oscar Eduardo Schwartz Justin. "Microstructural and superconducting properties of V doped MgB2 bulk and wires". 2004. http://etd.lib.fsu.edu/theses/available/etd-04072004-150501.
Texto completoAdvisor: Dr. Justin Schwartz, Florida State University, College of Engineering, Dept. of Mechanical Engineering. Title and description from dissertation home page (viewed June 17, 2004). Includes bibliographical references.
"Mechanical and superconducting properties of bulk bismuth superconductors at various processing stages". 2000. http://library.cuhk.edu.hk/record=b5890301.
Texto completoThesis (M.Phil.)--Chinese University of Hong Kong, 2000.
Includes bibliographical references.
Text in English; abstracts in English and Chinese.
by Yu-Kit Lam = Bi xi chao dao ti zai ge zhi bei jie duan zhi ji xie ji chao dao te xing / Lin Yujie.
Table of Contents --- p.i
Acknowledgments --- p.iv
Abstract --- p.v
Chapter Chapter 1 --- Related Work on Bulk Bi-based High Tc Superconductor --- p.1
Chapter 1.1 --- Historical Background of Superconductivity --- p.1
Chapter 1.2 --- Basic Properties of Superconductivity --- p.4
Chapter 1.3 --- Basic Properties of Bi-based Superconductor --- p.7
Chapter 1.4 --- Fabrication Methods of Bi-based Superconductor --- p.12
Chapter 1.4.1 --- Precursor Preparation --- p.12
Chapter 1.4.1.1 --- Solid State Reaction Method --- p.12
Chapter 1.4.1.2 --- Sol-gel Method --- p.15
Chapter 1.4.1.3 --- Co-decomposition Method --- p.17
Chapter 1.4.1.4 --- Freeze-drying and Spray-drying Methods --- p.17
Chapter 1.4.1.5 --- Comparison for precursor preparation methods --- p.18
Chapter 1.4.2 --- Pelletization and Sintering --- p.20
Chapter 1.5 --- Potential applications of Bi-based superconductors --- p.22
Chapter 1.5.1 --- Criteria for practical applications --- p.22
Chapter 1.5.2 --- Superconducting tapes --- p.23
Chapter 1.5.3 --- Current leads --- p.26
Chapter 1.6 --- Objectives of the Project --- p.27
Chapter 1.7 --- References --- p.28
Chapter Chapter 2 --- Fabrication of Bulk Bi(Pb)-2223 Superconductor --- p.33
Chapter 2.1 --- Introduction --- p.33
Chapter 2.2 --- Precursor Preparation --- p.33
Chapter 2.3 --- Grinding Process --- p.34
Chapter 2.4 --- Pelletization Process --- p.35
Chapter 2.5 --- The Sintering --- p.37
Chapter 2.6 --- Characterizations --- p.38
Chapter 2.7 --- References --- p.40
Chapter Chapter 3 --- Principles and Instruments of Characterizations --- p.41
Chapter 3.1 --- Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy --- p.41
Chapter 3.1.1 --- Basic Principle --- p.41
Chapter 3.1.2 --- Sample Preparation --- p.42
Chapter 3.2 --- Crystal Structure Determination Using X-ray Diffraction Spectroscopy --- p.44
Chapter 3.3 --- Vibrating Sample Magnetometer --- p.48
Chapter 3.3.1 --- Basic Principle --- p.48
Chapter 3.3.2 --- Sample Preparation --- p.49
Chapter 3.4 --- Standard Four-Probe Method for Electrical Measurement --- p.51
Chapter 3.5 --- Density Measurement of Sintered Samples --- p.52
Chapter 3.6 --- Hardness Tests --- p.54
Chapter 3.7 --- Determination of Flexural Strength of Sintered Samples --- p.56
Chapter 3.8 --- References --- p.57
Chapter Chapter 4 --- Results and Discussions
Chapter 4.1 --- Results from X-Ray Diffraction Spectroscopy --- p.58
Chapter 4.1.1 --- Green Pellet --- p.58
Chapter 4.1.2 --- 50-Hour Sintered Pellet --- p.58
Chapter 4.1.3 --- "100-Hour, 150-Hour, and 200-Hour Sintered Pellets" --- p.59
Chapter 4.1.4 --- Volume Fraction of the High Tc Phase --- p.59
Chapter 4.2 --- Microstructure Observed by Scanning Electron Microscopy --- p.63
Chapter 4.2.1 --- Green Pellet --- p.63
Chapter 4.2.2 --- 50-Hour Sintered Pellet --- p.64
Chapter 4.2.3 --- "100-Hour, 150-Hour, and 200-Hour Sintered Pellets" --- p.64
Chapter 4.3 --- Chemical Composition Using Energy Dispersive X-ray Spectroscopy --- p.68
Chapter 4.4 --- Results from Vibrating Sample Magnetometer --- p.71
Chapter 4.5 --- Densification of Sintered Samples --- p.75
Chapter 4.6 --- Hardness at Various Stages of Processing --- p.77
Chapter 4.7 --- Flexural Strength at Various Stages of Processing --- p.79
Chapter 4.8 --- I-V Characterization Using Standard Four-Probe Method --- p.82
Chapter 4.9 --- Weibull Modulii of Sintered Samples --- p.85
Chapter 4.10 --- Future Oultlook --- p.86
Chapter 4.11 --- References --- p.87
Chapter Chapter 5 --- Summary --- p.89
Appendix A Polishing of Pelletizing Mold
Chapter A.1 --- Introduction --- p.92
Chapter A.2 --- Grinding Process --- p.92
Chapter A.3 --- Final Polishing Process --- p.93
Yu-ChengShih y 施昱丞. "Study of Magnetic Drug Delivery System Using High Temperature Bulk Superconducting Magnet". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/bjwn4m.
Texto completoWU, JUN-YUAN y 吳俊元. "The study of Bi(Pb) Sr-Ca-Cu-O-superconducting bulk and film". Thesis, 1991. http://ndltd.ncl.edu.tw/handle/63130478491067031740.
Texto completoLin, Li-Fan y 林麗芳. "Ambient-pressure preparation and characterization of bulk and hin film of superconducting YBa2Cu4O8". Thesis, 1993. http://ndltd.ncl.edu.tw/handle/71973627814436881539.
Texto completoJIN, KE-SHU y 金克恕. "The study of YBa�浚u�記�f-y -Ag superconducting bulk and film". Thesis, 1992. http://ndltd.ncl.edu.tw/handle/77349440310973722162.
Texto completoLU, HSUEH CHUNG y 呂學忠. "The study of Superconductive Properties for Al and MgB2 nanoparticles and bulk". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/66641523677229466725.
Texto completo輔仁大學
物理學系
89
The main purpose of this article is to study the size effect on superconductivity in aluminum and MgB2 nanoparticles. The bulk and nanoparticle specimens of aluminum and MgB2 were prepared by arc welder and thermal evaporator respectively. Their specific heat and magnetization were performed by using a micro-calorimeter and a SQUID. It was observed that the superconducting critical temperature (TC) of Al could be increased by reducing the size of particle. The consequence is conjectured to be related to the phonon softening and the enhancement of phonon-electron interaction. In contrast to Al nanoparticles, no TC enhancement was observed in MgB2 nanoparticles. The magnetization measurements showed that the Meissner effect was slightly decreased in nanoparticles as compared to the bulk for MgB2. The mechanism of the result is not clear at this stage, the further experiments are arranged to clarify the observation.
Lin, Li-Fang y 林麗芳. "Ambient-pressure preparation and characterizations of bulk and thin film of superconducting YBaCuO". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/31253316261703388828.
Texto completoArcher, Jonathan Celvin. "Investigation into the synthesis and carbon doping of MgB₂for possible bulk superconducting fault current limiters application". Thesis, 2012. http://hdl.handle.net/10413/8954.
Texto completoThesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2012.
Nee, Chong-Sine y 倪中興. "Effects of the composition of compensating bulk on the phase formation of Pb-doped Tl-based high-Tc superconducting thin films". Thesis, 1997. http://ndltd.ncl.edu.tw/handle/43637271975544134738.
Texto completo國立交通大學
電子物理學系
85
Tl1Ba2Ca2Cu3O9-δ相(Tl-1223相)因為具有:1.相鄰兩單位晶胞內的銅氧 層間距較短(~8.8A); 以及2.超導臨界溫度高(Tc~115-120K)的優點,故在 應用潛力與超導性質的研究上均引起相當大的注意。但是1223相比起其他 兩種鉈系高溫超導相,Tl-2223相和Tl-2212相,因為成長的條件範圍較為 狹窄,使得製作過程中環境條件的控制較為嚴苛。本實驗在Tl-Ba-Ca-Cu- O系統中用鉛(Pb)取代部份的鉈(Tl),並改變退火時補償塊材的成份以及 熱處理條件來研究其對Tl-1223相形成之影響。以起始組成計量比接近 於1223的薄膜作為先驅膜,使用計量比為TBCCO-2223的塊材作為熱處理時 的補償,改變不同的氧氣壓力範圍,可以製作出接近純相的Tl-2223及 Tl-2212相薄膜。接著由製作出2223相的條件中,降低基板的溫度,製作 出純相的1212相的薄膜。然後藉著改變補償塊材中鉈的含量,找到了形 成1223相薄膜的條件。由實驗結果可以發現:除了氧氣分壓、基板的溫度 之外,補償塊材的組成成份,似乎是決定薄膜形成的超導相之最重要因數 。 Because of the following two merits: 1. the interlayer distance between two groups of Cu-O trilayers within a unit cell is short (~8.8A) compared to that of Tl-2223 and 2. the higher superconducting critical temperature (Tc ~ 115-120K) compared to that of YBCO. Tl1Ba2Ca2Cu3 O9-δ phase has been considered as a material of high application potential. As a result, it has attracted much attention recently. Nevertheless, the conditions for the forma-tion of the Tl-1223 phase are much more restrictive in comparison to that of the other two high-Tc phases of Tl-based superconductors, 2212 and 2223. In this study, we have tried to extend the formation conditions of Tl-1223 phase by partially substituting Tl with Pb, and by changing the composition of the compensating bulk material.Tl, Pb)-2212 phase were produced in different ranges of O2 gas pressure by using the precursor films with nominal stoichiomentry of Tl:Ba:Ca:Cu = 1:2:2:3 and compensated by bulk material with nominal stoichiomentry of Tl:Ba:Ca:Cu = 2:2:2:3 during annealing. By reducing the anneal temperature under essentially the same conditions, the phase formed in the film became mostly (Tl,Pb)-1212 phase. More interestingly, it was found that the formation of (Tl,Pb)-1223 phase can be realized only by changing the Tl content of the compensating bulks. The results imply that the composition of the compensating bulk may have played a major role in determining the phases formed during post annealing process regardless of the starting composition of the precursor films.
Wang, Jyh-Lih. "Study of current limiting mechanisms in Bi-Sr-Ca-Cu-O superconducting tapes by electromagnetic and microstructural characterization of bulk scale bicrystals". 1996. http://catalog.hathitrust.org/api/volumes/oclc/35677796.html.
Texto completo早川, 直樹, 仁. 大久保, 克巳 加藤 y Klaus-Peter Juengst. "高温超伝導バルク導体を用いた超伝導限流変圧器の開発に関する研究". 2004. http://hdl.handle.net/2237/13122.
Texto completo