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Theoretical modeling and experimental characterization of planar defects in Y sub 2 Ba sub 4 Cu sub 6+x O sub 14+x

Description: Crystallographic defects and phase transformations in the system Y{sub 2}Ba{sub 4}Cu{sub 6 + x}O{sub 14 + x}(0{le}{times}{le}4) are investigated by high resolution transmission electron microscopy (TEM) and static lattice, three dimensional Monte Carlo computer simulations. High resolution images of partially transformed (x = 2 to x = 1) material reveal a prevalence of CuO planar defects (stacking faults) associated with the transformation and an absence of disturbance to the perovskite Ba-Y-Ba… more
Date: November 1, 1990
Creator: Burmester, C. P.; Fendorf, M.; Gronsky, R. & Wille, L. T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Application of MeV ions to the analysis and modification of high temperature superconducting materials

Description: In analyzing the composition of high {Tc} superconducting materials using heavy-ion RBS we discovered that the electronic excitation of the target caused mixing to occur. To study this effect we made superlattice structures of alternating thin layers of Ba{sub 2}YCu{sub 3}O{sub 6+x} and BaF{sub 2}. At this point in the process some mixing has occurred, but the individual layers are still visible. However, as the bombardment continued the layers were mixed together. It may well be that one can u… more
Date: November 2, 1990
Creator: Tombrello, T.A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Magnetic flux noise in copper oxide superconductors

Description: Magnetic flux noise and flux creep in thin films and single crystals of YBa{sub 2}Cu{sub 3}O{sub 7-x}, Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+x}, Tl{sub 2}Ca{sub 2}Ba{sub 2}Cu{sub 3}O{sub x}, and TlCa{sub 2}Ba{sub 2}Cu{sub 3}O{sub x} are measured with a superconducting quantum interference device (SQUID). The noise power spectrum generally scales as 1/f (f is frequency) from 1 Hz to 1 kHz, increases with temperature, and decreases in higher-quality films. It is proportional to the magnetic field … more
Date: November 1, 1991
Creator: Ferrari, M.J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Characterization of hot isostatically pressed Bi-Sr-Ca-Cu-O as a function of consolidation variables

Description: Fully dense, bulk Bi{sub 2}Sr{sub 1.7}CaCu{sub 2}O{sub x} (2212) superconductor pellets were made by hot isostatic pressing in an inert atmosphere. Electron microscopy revealed that rotation and bending of the platelike 2212 grains were responsible for much of the densification. Under processing conditions of 825{degrees}C and 105 MPa, dense pellets were obtained in 15 min. Many dislocations, planar faults, and, perhaps, intergrowths of the Bi{sub 2}Sr{sub 2}CuO{sub x} phase were produced durin… more
Date: November 1, 1991
Creator: Goretta, K. C.; Miller, D. J.; Poeppel, R. B. & Nash, A. S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Phase instability at the maximum Tc in oxide superconductors: Phase separation in La sub 2 CuO sub 4+x , Nd sub 2 minus x Ce sub x CuO sub 4 , and La sub 2 minus x Sr sub x CuO sub 4

Description: Observation of similar behavior in three different superconducting oxides suggests that the maximum {Tc} is limited by phase instability. These conclusions are based on previously published neutron powder diffraction data for La{sub 2}CuO{sub 4+x} and Nd{sub 2-x}Ce{sub x}CuO{sub 4} and new data for La{sub 2-x}Sr{sub x}CuO{sub 4} which show a phase separated region for compositions adjacent to that which produces the highest {Tc}. 13 refs., 7 figs.
Date: November 1, 1990
Creator: Jorgensen, J.D.; Lightfoot, P.; Pei, Shiyou; Richards, D.R.; Hinks, D.G. (Argonne National Lab., IL (USA)) & Dabrowski, B. (Argonne National Lab., IL (USA) Northern Illinois Univ., Dekalb, IL (USA))
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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X-ray studies of microstructures in semiconductors and superconducting materials

Description: Several different experimental investigations were carried out during the present report period. These include x-ray studies of semiconductors, high-{Tc} superconductors, and various thin films using synchrotron radiation (especially soft x-ray experiments by means of our new detector) and measurements of some fundamental properties of new superconducting materials made in our laboratory at Buffalo. We have made the first systematic study of electronic structure in the high-{Tc} superconductors… more
Date: November 12, 1991
Creator: Kao, Y. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Cross-flow, filter-sorbent catalyst for particulate, SO sub 2 and NO sub x control

Description: The device described in this report will simultaneously remove particulates, SO{sub 2} and NO{sub x} from the combustion gases of coal combustors. The device is configured as a cross-flow filter. The gas flows from the inlet passages to orthogonally oriented discharge channels via thin, multilayered porous walls. Flue gas enters from both the front and back of the device. With the left wall of the filter sealed, gas discharges from the right side of the device. The key to combined physical (fly… more
Date: November 1, 1990
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A comparison of twin boundary pinning in nearly fully stoichiometric and oxygen deficient YBa[sub 2]Cu[sub 3]O[sub 7-[delta]]

Description: The angular dependence of the magnetoresistance was measured on the same single crystal of a YBa[sub 2]Cu[sub 3]O[sub 7-[delta]] prepared initially with a superconducting transition temperature of 93.0K and then annealed to obtain a transition temperature of 56.9K. A second oxygen deficient sample was produced with a transition temperature 57.0K and nearly identical transport characteristics. Twin boundary pinning superimposed on flux flow behavior was observed in both the 56.9K and 93.0K state… more
Date: November 1, 1992
Creator: Fleshler, S.; Kwok, W. K.; Welp, U.; Downey, J. & Crabtree, G. W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Corrosion product identification and relative rates of corrosion of candidate metals in an irradiated air-steam environment

Description: Previously reported work by others indicates that dicopper trihydroxide nitrate, Cu{sub 2}NO{sub 3}(OH){sub 3}, forms on copper and copper alloys subjected to irradiated moist air near room temperature. We have performed experiments over a range of temperature and humidity, and have found that this species is formed at temperatures up to at least 150{degree}C if low to intermediate relative humidities are present. At 150{degree}C and 100% relative humidity, only Cu{sub 2}O and CuO were observed… more
Date: November 3, 1989
Creator: Reed, D. T.; Swayambunathan, V.; Tani, B. S. & Van Konynenburg, R. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Irradiation defect structures in YBa sub 2 Cu sub 3 O sub 7 minus x and their correlation with superconducting properties

Description: We review our work on irradiation effects in single crystal YBa{sub 2}CU{sub 3}O{sub 7-x}. Transmission electron microscopy has been employed to study the defect microstructures produced by irradiations with fast neutrons, MeV ions (Kr, Ne and p), and electrons. The atomic structure within defect cascades was investigated using 50 keV Kr and Xe ion irradiations to low doses. Evidence is shown for an amorphous structure with some incoherent recrystallization within individual cascades. Correlati… more
Date: November 1, 1990
Creator: Kirk, M.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Cooling rate effects on the microstructure, critical current density, and {Tc} transition of one- and two-powder BSCCO-2223 Ag-sheathed tapes

Description: An important variable controlling the critical current density (J{sub c}) of Ag-sheathed BSCCO-2223 tapes is the degree of phase purity of the reacted tapes. Most correlations between J{sub c} and microstructure show that it is highly desirable to reduce the amount of non-superconducting second phases to as low a level as practical. In recent studies of the influence of cooling rate after the final reaction, we find contradictions to this general rule. The J{sub c} (77 K, 0 T) of so-called {ope… more
Date: November 1, 1994
Creator: Parrell, J. A.; Larbalestier, D. C. & Dorris, S. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Ion-assisted laser deposition of intermediate layers for YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} thin film growth on polycrystalline and amorphous substrates

Description: The growth of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) high-temperature superconductor thin films has largely been limited to deposition on single-crystal substrates to date. In order to expand the range of potential applications, growth on polycrystalline and amorphous substrates is desirable. In particular, the deposition of YBCO thin films with high critical current densities on polycrystalline metal alloys would allow the manufacture of superconducting tapes. However, it is shown that it … more
Date: November 1, 1993
Creator: Reade, R. P.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
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Liquid and solid solubility of Ag in Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}

Description: Currently, leading candidates for usable high temperature superconducting wires are Bi-Sr-Ca-Cu-0 tapes produced by modifying the powder in tube process. In order to obtain crystallographic texture, these tapes are processed by partial melting then slow cooling through the peritectic. While it is well known that Ag suppresses the lowest liquidus temperature of the Bi based materials, no serious investigation of the Bi-Sr-Ca-CuO-Ag phase diagram has been undertaken. Solubilities of Ag in Bi2212 … more
Date: November 1, 1993
Creator: McCallum, R. W.; Dennis, K. W.; Margulies, L. & Kramer, M. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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X-ray studies of microstructures in semiconductors and superconducting materials. Annual technical progress report, July 1, 1990--June 30, 1991

Description: Several different experimental investigations were carried out during the present report period. These include x-ray studies of semiconductors, high-{Tc} superconductors, and various thin films using synchrotron radiation (especially soft x-ray experiments by means of our new detector) and measurements of some fundamental properties of new superconducting materials made in our laboratory at Buffalo. We have made the first systematic study of electronic structure in the high-{Tc} superconductors… more
Date: November 12, 1991
Creator: Kao, Y. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Characterization of hot isostatically pressed Bi-Sr-Ca-Cu-O as a function of consolidation variables

Description: Fully dense, bulk Bi{sub 2}Sr{sub 1.7}CaCu{sub 2}O{sub x} (2212) superconductor pellets were made by hot isostatic pressing in an inert atmosphere. Electron microscopy revealed that rotation and bending of the platelike 2212 grains were responsible for much of the densification. Under processing conditions of 825{degrees}C and 105 MPa, dense pellets were obtained in 15 min. Many dislocations, planar faults, and, perhaps, intergrowths of the Bi{sub 2}Sr{sub 2}CuO{sub x} phase were produced durin… more
Date: November 1, 1991
Creator: Goretta, K. C.; Miller, D. J.; Poeppel, R. B. & Nash, A. S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Magnetic flux noise in copper oxide superconductors

Description: Magnetic flux noise and flux creep in thin films and single crystals of YBa{sub 2}Cu{sub 3}O{sub 7-x}, Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+x}, Tl{sub 2}Ca{sub 2}Ba{sub 2}Cu{sub 3}O{sub x}, and TlCa{sub 2}Ba{sub 2}Cu{sub 3}O{sub x} are measured with a superconducting quantum interference device (SQUID). The noise power spectrum generally scales as 1/f (f is frequency) from 1 Hz to 1 kHz, increases with temperature, and decreases in higher-quality films. It is proportional to the magnetic field … more
Date: November 1, 1991
Creator: Ferrari, M. J.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
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c-Axis Projected Electron-Positron Momentum Density in YBa{sub 2}Cu{sub 3}O{sub 7}

Description: The authors present the theoretical c-axis projected electron-positron momentum density N{sub 2{gamma}}(P{sub x},p{sub y}) in YBa{sub 2}Cu{sub 3}O{sub 7} based on the local density approximation (LDA) framework along various lines in momentum space. The calculations use the Korringa-Kohn-Rostoker (KKR) band structure formalism. The anisotropic distribution defined by taking cuts through the calculated spectra along different lines in the (p{sub x},p{sub y}) plane possesses complex structures wh… more
Date: November 1, 1990
Creator: Bansil, A.; Mijnarends, P. E. & Smedskjaer, L. C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Progress in the development of BSCCO-2212 superconductors

Description: BSCCO-2212 powders were uniformly dip coated on silver ribbons of 1 meter lengths. Short sample sandwiches of various combinations of silver and the dip coated ribbon were reacted to form possible conductor geometries for characterization and testing. Optical and Scanning Electron Microscope (SEM) examination of surfaces and cross sections showed good but still not ideal microstructure. Representative critical current densities at 6 T and 4.2 K ranged from 8 {times} 10{sup 3}A/cm{sup 2} for san… more
Date: November 1, 1992
Creator: Walker, M. S. & Dietderich, D. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Halogenated high {Tc} superconductors and method of preparation

Description: Disclosed is a method for producing a superconductor of the R-Ba-Cu-O system which comprises of selecting an insulating material of the formula RBa{sub x}Cu{sub y}O{sub z} where R is selected from the group consisting of Y, La, Pr, Nd, Sm, Eu, Gd, Ho, Er, Tm, and Lu, and where x ranges from about 1.7 to about 2.3, y ranges from about 2.7 to about 3.3 and z ranges from about 5.0 to about 6.99, and halogenating said material with a halogen selected from the group consisting of chlorine, bromine, … more
Date: November 14, 1990
Creator: Radousky, H. B.; Glass, R. S. & Fluss, M. J.
Item Type: Refine your search to only Patent
Partner: UNT Libraries Government Documents Department
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Cross-flow, filter-sorbet catalyst for particulate, SO{sub 2} and NO{sub x} control. Fourth quarterly technical progress report

Description: This report describes a new concept for integrated pollutant control: A cross-flow filter comprised of layered, gas permeable membranes that act as a particulate filter, an SO{sub 2} sorbent, and a NO{sub x} reduction catalyst.
Date: November 1, 1990
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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SYNTHESIS AND STORAGE OF SMALL QUANTITIES OF TRITIATED WATER

Description: A method that can be used to produce milliliter amounts of tritiated water from tritium gas is described. Safety precautions are emphasized as part of the method, which involves oxidation of tritium gas over hot copper(II) oxide in a sealed glass system. (auth)
Date: November 22, 1957
Creator: Whittemore, I. M. & Lehman, R. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Investigation of Mixed Metal Sorbent / Catalysts for the Simultaneous Removal of Sulfur and Nitrogen Oxides

Description: Simultaneous removal of SO{sub 2} and NO{sub x} using a regenerable solid sorbent will constitute an important improvement over the use of separate processes for the removal of these two pollutants from stack gases and possibly eliminate several shortcomings of the individual SO{sub 2} and NO{sub x} removal operations. The work done at PETC and the DOE-funded research of the investigators on the sulfation and regeneration of alumina-supported cerium oxide sorbents have shown that they can perfo… more
Date: November 30, 1999
Creator: Akyurtlu, Ates & Akyurtlu, Jale F.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A mechanism for resistive dissipation in Ag sheathed Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} and Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10}

Description: Detailed measurements of the V-I curves for a number of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} and Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10}/Ag composite tapes were made at 4.2, 27, and 64-77 K as a function of applied magnetic field as well as the angle between the tape face and the direction of applied field. Results suggest that the weak vortex-pinning strength, and the amount of the weakly coupled grain boundaries and of the non-superconducting volume are primary limiting factors for cri… more
Date: November 1, 1993
Creator: Suenaga, M.; Li, Q.; Sabatini, R.L.; Shibutani, K.; Hayoashi, S.; Ogawa, R. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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HTS wire irradiation test with 8 GeV protons

Description: The radiation level at High Energy Particle Accelerators (HEPA) is relatively high. Any active component which should be close to the accelerator has to be radiation hard. Since High Temperature Superconductors (HTS) have a great potential to be used in HEPAs (e.g., in superconducting magnets, current leads, RF cavities), it is important to understand the radiation hardness of these materials. A radiation test of HTS wire (Bi-2223) was performed at Fermilab. The HTS sample was irradiated with 8… more
Date: November 2, 1999
Creator: Feher, S.; Glass, H.; Huang, Y.; Limon, P.J.; Orris, D.F.; Schlabach, P. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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