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Topic Area: Materials Science

Displaying records 371 to 380 of 428 records.
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371. Combining Magnets and Dielectrics: Crystal Chemistry in the BaO-Fe^d2^O^d3^-TiO^d2^ System
Topic: Materials Science
Published: 4/1/2003
Authors: T Siegrist, Terrell A Vanderah
Abstract: Phases observed in the Ba-Fe-Ti-O system are classified and described within the framework of close packed [O,Ba/O] layers, with the transition metals in either octahedral (titanium and iron) or tetrahedral (iron only) sites. The resulting crystal c ...
http://nist.gov/manuscript-publication-search.cfm?pub_id=850669

372. Intermetallics Formation and Growth at the Interface of Tin-Based Solder Alloys and Copper Substrates
Topic: Materials Science
Published: 2/17/2003
Authors: Juan C Madeni, S X Liu, Thomas Allen Siewert
Abstract: Increasing concerns regarding environmental contamination is driving the soldering research community to develop lead-free solder alloys. Previous studies have shown that Sn-based alloys such as Sn-3.5Ag, Sn-0.7Cu, Sn-9Zn, and Sn-3.2Ag-O. ...
http://nist.gov/manuscript-publication-search.cfm?pub_id=851327

373. Subsolidus Phase Equilibria and Crystal Chemistry in the System BaO-TiO^d2^-Ta^d2^O^d5^
Topic: Materials Science
Published: 1/1/2003
Authors: Terrell A Vanderah, Robert S. Roth, T Siegrist, W Febo, J. M. Loezos, Winnie K Wong-Ng
Abstract: Subsolidus phase relations have been determined for the BaO: TiO^d2^Ta^d2^O^d5^ system. Approximately 100 specimens were prepared in air at temperatures near but below the solidus (1275 C to 1500 C). For the binary BaO: Ta^d2^O^d5^ subsystem, the ...
http://nist.gov/manuscript-publication-search.cfm?pub_id=850602

374. Phase Equilibria and Crystal Chemistry in the BaO-Al^d2^O^d3^-Nb^d2^O^d5^ and BaO-Nb^d2^O^d5^ Systems
Topic: Materials Science
Published: 11/1/2002
Authors: Terrell A Vanderah, B C Collins, Winnie K Wong-Ng, Robert S. Roth, L Farber
Abstract: Subsolidus phase equilibria in the BaO:Al^d2^O^d3^:Nb^d2^O^d5^ system at ~1250 C in air have been determined. Ternary compound formation in this system is limited to one new phase, Ba^d5.75^Al^d0.75^Nb^d9.25^O^d30^ (Ba^d6-x^Al^d1-x^Nb9+xO30, x=0.25; ...
http://nist.gov/manuscript-publication-search.cfm?pub_id=850531

375. Talking Ceramics
Topic: Materials Science
Published: 11/1/2002
Author: Terrell A Vanderah
Abstract: This is an invited Perspective article describing the technical needs and state-of-the-art research activities in the materials science of microwave ceramics, especially dielectric materials which serve as critical elements in resonators and filters ...
http://nist.gov/manuscript-publication-search.cfm?pub_id=850668

376. Application of an On-Line Weld Monitoring System
Topic: Materials Science
Published: 9/12/2002
Authors: Thomas Allen Siewert, Ivan Samardzic, Stefanija Klaric
Abstract: quisition analysis and real-time manipulation of the welding parameters offer added controls over the weld quality. Thanks to the continual development of information technology and electronics, it is possible to improve the systems for monitoring ...
http://nist.gov/manuscript-publication-search.cfm?pub_id=851294

377. Acoustic Spectroscopy of Lithium Niobate: Elastic and Piezoelectric Coefficient
Topic: Materials Science
Published: 9/1/2002
Authors: H Ogi, Y Kawashima, M Hirao, H M Ledbetter
Abstract: We report the first Simultaneous measurement of a crystal's complete elastic and piezoelectric coefficients: C^dif^, e^dijk^. The studied crystal was lithium niobate (LiNbO^d3^) with trigonal crystal symmetry (3 m point group), thus six independent ...
http://nist.gov/manuscript-publication-search.cfm?pub_id=851242

378. Crystal Structure of Ba^d27^Fe^d16^Ti^d33^O^d117^
Topic: Materials Science
Published: 7/1/2002
Authors: T Siegrist, Terrell A Vanderah, C Svensson, Robert S. Roth
Abstract: Single-crystal X-ray diffraction studies indicate that the compound Ba^d27^Fe^d16^Ti^d33^O^d117^- crystallizes in the rhombohedral space group R-3m, with a hexagonal unit cell a=5.7400(8) , c=127.11(3) ; Z=1.5. The arrangement may be described as ...
http://nist.gov/manuscript-publication-search.cfm?pub_id=850585

379. Lattice Statice Green's Function Method for Multiscale Modeling of Point Defects and Extended Defects in Solids
Topic: Materials Science
Published: 7/1/2002
Author: Vinod K Tewary
Abstract: A method for multiscale modeling of point defects such as vacnacies and interstitials at the atomistic level and extended defects such as free surfaces and interfaces at the macroscopic continuum level in a solid is described. The method is based up ...
http://nist.gov/manuscript-publication-search.cfm?pub_id=851303

380. Reliability Improvements in Repair Welding of High Strength Steels
Topic: Materials Science
Published: 7/1/2002
Authors: Ivan Samardzic, Thomas Allen Siewert
Abstract: Engineers often have to deal with repair of weldments after they have been put into service. Here, the concern is that the service environment may have changed the structure, indepent of whether the problems originated during the initial constructio ...
http://nist.gov/manuscript-publication-search.cfm?pub_id=851372