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Search Publications by: Winnie Wong-Ng (Fed)

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Displaying 251 - 274 of 274

DTA/TGA Study of Eutectic Melting in the System BaF 2 -BaO-Y 2 O 3 -CuO x -H 2 O

July 1, 2001
Author(s)
Lawrence P. Cook, Winnie K. Wong-Ng, J Suh
Differential thermal analysis and thermogravimetric analysis (DTA/TGA) experiments have been completed in the BaF2-BaO-Y2O3-CuOx-H2O system at various oxygen pressures to determine the effect of adding BaF2 and H2O on the eutectic melting in the system BaO

The 103rd Annual Meeting of the American Ceramic Society

March 19, 2001
Author(s)
Winnie K. Wong-Ng
The American Ceramic Society 103rd annual meeting & exposition took place from April 22-25, 2001, at the Indiana Convention Center and RCA Dome of Indianapolis. The meeting was well attended - with approximately 2700 attendees including many from other

Phase Diagrams of High Tc Superconductors

March 13, 2001
Author(s)
Winnie K. Wong-Ng
The aim of this chapter is to provide selected experimental phase diagrams of high Tc superconductors to represent various active systems of research. Among current systems, the BaO-Y 2O 3-CuO (BYC), BaO-R 2O 3-CuO (BRC), and BSCCO systems have been

Development of Low Cost (Sr,Ca) 3 Al 2 O 6 Dielectrics for Bi 2 Sr 2 CaCu 2 O 8+d Applications

March 1, 2001
Author(s)
T J. Haugan, Winnie K. Wong-Ng, Lawrence P. Cook, Richard G. Geyer, H J. Brown, L Swartzendruber, James A. Kaduk
The development of low-cost (Sr,Ca)3Al2O6 dielectrics for Bi2Sr2CaCu2O8+d superconductor applications was investigated. The (Sr,Ca)3Al2O6 phase was determined to be inert to Bi2Sr2CaCu2O8+d with extended high temperature subsolidus annealing, and also

Crystal Structure of the Monoclinic Perovskite Sr 3.94Ca d1.31^Bi 2.70 O 12

December 1, 2000
Author(s)
Winnie K. Wong-Ng, James A. Kaduk, Qingzhen Huang, Robert S. Roth
The crystal structure of the low temperature oxidized form of Sr 3.94Ca 1.31Bi 2.70O 12 has been determined using a combined Rietveld refinement technique with neutron, synchrotron, and powder x-ray diffraction data. The structure is pseudo-orthorhombic

NIST Centennial Celebration - Crystallographic Highlights

December 1, 2000
Author(s)
Winnie K. Wong-Ng, Alan D. Mighell, Gabrielle G. Long, Leonid A. Bendersky, Vicky L. Karen, J D. Barnes, G L. Gilliland, T Gallagher, Terrell A. Vanderah, R G. Munro, Paul E. Stutzman, H F. McMurdie, S Block, Gasper J. Piermarini, Robert S. Roth, Antonio Santoro, Curt W. Reimann, C R. Hubbard, John W. Cahn, E Prince, D R. Lide, H Ondik, Lawrence P. Cook, T Siegrist, G DeTitta, L Finger, H Evans, E Gabe, G Enright, J T. Armstrong, M Levenson, Laurence C. Chow, Shozo Takagi, M Mathew, Jeffrey W. Lynn, H S. Peiser
NIST has a long history of crystallographic research, and has made significant contributions to the advancement of the fields of crystallography, biology, and materials science. The articles are contributed by scientists from various divisions at NIST, and

NIST Centennial Celebration Symposium Highlight

November 15, 2000
Author(s)
Alan D. Mighell, Winnie K. Wong-Ng
The Centennial Celebration of the National Institute of Standards and Technology (NIST), formerly known as the Bureau of Standards (NBS), takes place in the year 2001. NIST has a long history (>50 years) of crystallographic research, and has made

Flux Pinning of Bi 2 Sr 2 CaCu 2 O 8+g /Ag Superconductors Utilizing (Sr,Ca) 14 Cu 24 O 41 Defects and Nanophase Al 2 O 3 and Au Particles

June 1, 2000
Author(s)
T J. Haugan, Winnie K. Wong-Ng, Lawrence P. Cook, H J. Brown, L Swartzendruber, D T. Shaw
Investigations into flux pinning of Bi 2Sr 2 CaCu 2O 8+γ /Ag (Bi-2212/Ag) thick film conductors utilizing micron-sized (Sr,Ca) 14Cu 24O 41 and nanophase Al 2O 3 and Au particles are described. Addition of defect particles delayed and reduced formation of

Vapor Pressure of the SrPbO 3 Perovskite Phase

April 1, 2000
Author(s)
Lawrence P. Cook, Winnie K. Wong-Ng
The perovskite phase SrPbO 3 is important as a buffer and indicator of PbO chemical potential (at fixed p O2 ) according to the reaction: 2 SrPbO 3 --> Sr 2PbO 4 + PbO(g) + 1/2 O2 (g), where the term PbO(g) includes several Pb-containing gaseous species

Effect of Ag on the Primary Phase Field of High T c (Bi,Pb)-2223 Superconductor

February 1, 2000
Author(s)
Winnie K. Wong-Ng, Lawrence P. Cook, W Greenwood, Anthony J. Kearsley
The subsolidus equilibria and the primary phase field (crystallization field) of the 110K high T c (Bi,Pb)-2223 ([Bi,Pb]:Sr:Ca:Cu) superconductor in the presence of Ag have been determined under 7.5 volume % O 2 (92.5 % Ar). A total of 29 six-phase volumes

Phase Relations of the SrO-Ho 2 O 3 -CuO x System

February 1, 2000
Author(s)
Winnie K. Wong-Ng, J Dillingham, Lawrence P. Cook
The phase diagram of the SrO-R 2O 3-CuOx system, where R=Ho, was investigated in air. The tie-line relationships of this system were determined. Two ternary phases were found, namely, the green phase SrHo 2CuO 5 and the A14-24 solid solution (Sr 14-xHo x

Structural investigation of (Sr 4-d Ca d )PtO 6 Using X-Ray Rietveld Refinement

August 16, 1999
Author(s)
Winnie K. Wong-Ng, James A. Kaduk, R A. Young, F Jiang
The structures of the solid solution series (Sr 4-δCa δ)PtO 6, with δ = 0, 0.85(1), 2, and 3, have been investigated using the Rietveld refinement technique with laboratory x-ray powder data. A complete solid solution between Sr and Ca was confirmed to

Local Environments of Three Forms of Ba 2 Ycu 3 O 6+x

March 12, 1999
Author(s)
Winnie K. Wong-Ng, M Melamud, Lawrence H. Bennett
The Wigner-Seitz local atomic cell construction procedure, provides a topological means for comparing series of related structures in terms of the number and type of nearest neighbors. We used this construction to further our understanding of the chemical

Characterization of Ternary Compounds in the BaO:Fe 2 O 3 :TiO 2 System: Ba 6 Fe 45 Ti 17 O 106 and BaFe 11 Ti 3 O 23

January 1, 1999
Author(s)
Terrell A. Vanderah, Winnie K. Wong-Ng, B H. Toby, V. M. Browning, Robert D. Shull, Richard G. Geyer, Robert S. Roth
Single crystals of Ba 6Fe 45Ti 17O 106 and BaFe 11Ti 3O 23 were obtained as major and minor co-products, respectively, by slow-cooling an off-stoichiometric BaO:Fe 2O 3:TiO 2 melt. The former compound exhibits variable stoichiometry Ba 6Fe 48-xTi 14+xO 106

Effect of P o2 and Ag on the Phase Formation of the Pb-2223 Superconductor

June 25, 1998
Author(s)
Winnie K. Wong-Ng, Lawrence P. Cook, W Greenwood
The chemical reactions and the compositional characteristics of liquids which lead to the phase formation of the Pb-2223 ((Bi,Pb):Sr:Ca:Cu:O) superconductor have been studied for a precursor composition of Bi 1.8Pb o.4Sr 2Ca 2.2Cu 3O x. The combined

Pb-Distribution in a Five-Phase (Bi, Pd)-Sr-Ca-Cu-O Assemblage

March 12, 1998
Author(s)
Lawrence P. Cook, Winnie K. Wong-Ng
The partitioning of lead between phases in the nominal five-phase assemblage: (Pb,Bi) 3Sr 2Ca 2CuO x + (Ca,Sr) 2PbO 4 + (Bi,Pb) 2Sr 2CaCu 2O x + (Ca,Sr)O + Liquid has been investigated in an atmosphere of 7.5% O 2925% Ar. Samples were studied using a