| Small Angle Neutron Scattering (SANS) Characterization of Electrically Conducting Polyaniline Nanofiber/Polyimide Nanocomposites |
25 Oct 2011 |
17 pages |
| Authors:
Alan R Hopkins; Sandra J Tomczak; Vandana Vij; Andrew J Jackson; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
 | Nanocomposites of polyaniline nanofibers and polyimide were fabricated and studied using small angle neutron scattering (SANS). The immiscible nature of the conformationally dissimilar polyaniline nanofiber and polyimide host is established by a series of experiments involving neutron scattering. Based on these techniques, we conclude that the crystal structure of the polyimides is not disrupted, and that there is no mixing between the two components on a molecular level. The morphology ... |
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| Positive Vibrational Entropy of Chemical Ordering in FeV |
08 Sep 2011 |
5 pages |
| Authors:
J A Munoz; M S Lucas; O Delaire; M L Winterrose; L Mauger; Chen W Li; A O Sheets; M B Stone; D L Abernathy; Yuming Xiao; CALIFORNIA INST OF TECHNOLOGY PASADENA W M KECK LAB
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| Inelastic neutron scattering and nuclear resonant inelastic x-ray scattering were used to measure phonon spectra of FeVas a B2 ordered compound and as a bcc solid solution. The two data sets were combined to give an accurate phonon density of states, and the phonon partial densities of states for V and Fe atoms. Contrary to the behavior of ordering alloys studied to date, the phonons in the B2 ordered phase ... |
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| Incommensurate Magnetism in FeAs Strips: Neutron Scattering from CaFe4As3 |
21 DEC 2010 |
6 pages |
| Authors:
Yusuke Nambu; Liang L. Zhao; Emilia Morosan; Kyoo Kim; Gabriel Kotliar; Pawel Zajdel; Mark A. Green; William Ratcliff; Jose A. Rodriguez-Rivera; Collin Broholm; JOHNS HOPKINS UNIV BALTIMORE MD DEPT OF PHYSICS AND ASTRONOMY
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| Magnetism in the orthorhombic metal CaFe4As3 was examined through neutron diffraction for powder and single crystalline samples. Incommensurate (qm approx. equal to (0.37-0.39) x b*) and predominantly longitudinally (|| b) modulated order develops through a 2nd order phase transition at TN = 89.63(6) K with a 3D Heisenberg-like critical exponent Beta = 0.365(6). A 1st order transition at T2 = 25.6(9) K is associated with the development of a transverse ... |
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| Resolution of the Spatial Distribution of the Bacteriophage MS2 Protein and RNA Components |
MAY 2005 |
23 pages |
| Authors:
Deborah A. Kuzmanovic; Iiya Elashvili; Charles H. Wick; Catherine O'Connell; Susan Krueger; GEO-CENTERS INC ABERDEEN PROVING GROUND MD
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| Small-angle neutron scattering (SANS) and the contrast variation technique were used to determine the spatial relationship of the individual components of the MS2 virion (protein shell and genomic RNA). Our results show that (a) the MS2 RNA is tightly compacted within the virion, confined to a radius of 83 +/- lA and (0) the MS2 coat protein shell extends to a radius of 136 + 2A and has a thickness ... |
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| Clay Delamination in Clay/Poly(Dicyclopentadiene) Nanocomposites Quantified by Small Angle Neutron Scattering and High-Resolution Transmission Electron Microscopy |
2005 |
15 pages |
| Authors:
Mitra Yoonessi; Hossien Toghiani; Tyrone L. Daulton; Jar-Shyong Lin; Jr Pittman Charles U.; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS SEAFLOOR SCIENCES DIRECTORATE
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| Highly delaminated clay/poly(dicyclopentadiene) nanocomposites were prepared by in-situ, ring-opening metathesis polymerization of presonicated mixtures of the liquid dicyclopentadiene (DCPD) and organically modified Montmorillonite clays. Three nanocomposite series of increasing clay loadings and modified Montmorillonite PGW were synthesized. The dispersed microstructure of the clays in the nanocomposites was characterized by small-angle neutron scattering (SANS), ultra-small-angle neutron scattering (USANS), small-angle X-ray scattering (SAXS), and high-resolution transmission electron microscopy (HR-TEM). All clays were ... |
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| Mechanically Milled Iron Alloys for High-Temperature Magnetic and Structural Applications |
29 AUG 2003 |
13 pages |
| Authors:
Anthony S. Arrott; Carey E. Stronach; David R. Noakes; VIRGINIA STATE UNIV PETERSBURG
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| Mechanically-milled alloys of iron with cobalt ("Hyperco")and aluminum have been fabricated with a puck-and-saucer mill, and have been studied with the bulk magnetization, differential scanning spectrometry, neutron scattering and muon spin rotation techniques. One as-yet-unresolved problem is that of compaction. Two major discoveries concerning iron-aluminum alloys were made during this reporting period, inverse melting, and the presence of incommensurate static spin-density waves. A laboratory for preparation and characterization of magnetically-ordered ... |
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| High Temperature Materials Simulations on Parallel Computers |
30 APR 2003 |
20 pages |
| Authors:
Priya Vashishta; Rajiv K. Kalia; Aiichiro Nakano; LOUISIANA STATE UNIV BATON ROUGE
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| Final Progress (1 May 99 - 30 Apr 03): This project deals with properties and processes in high-temperature materials (HTMs) that are vital to the DoD technology base. In this project, molecular-dynamics (MD) simulations have been performed to investigate: i) sintering of nanostructured SiC and high- pressure structural transformation in SiC; ii) dynamic fracture in nanostructured systems; iii) structure of amorphous Al2O3; and iv) reactive wetting of Al2O3 surface by ... |
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| The Sintering and Densification Behavior of an Iron Nanopowder Characterized by Comparative Methods |
FEB 2003 |
40 pages |
| Authors:
Laszlo J. Kecskes; Robert H. Woodman; Samuel F. Trevino; Bradley R. Klotz; S. G. Hirsch; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| Fe nanopowder, derived from microwave plasma synthesis (Materials Modifications Inc., Fairfax, VA), was obtained and characterized for particle size and size distribution. The methods used included static light scattering (SLS) and dynamic light scattering (DLS), surface area and size by Brunauer, Emmett, and Teller (BET) analysis, small angle neutron scattering (SANS), neutron diffraction (ND), x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Based on ... |
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| Characterization of Metal-Oxide Nanoparticles: Synthesis and Dispersion in Polymeric Coatings |
2003 |
7 pages |
| Authors:
Li-Piin Sung; Stephanie Scierka; Mana Baghai-Anaraki; Derek L. Ho; NATIONAL INST OF STANDARDS AND TECHNOLOGY GAITHERSBURG MD
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| Metal-oxide nanoparticles can be used to optimize UV absorption and to enhance the stiffness, toughness, and probably the service life of polymeric materials, Characterization of the nano- and microstructure dispersion of particles is necessary to optimize the structure-property relationships. Characterizations of both TiO2 particles dispersed in an acrylic-urethane matrix and TiO2 nanostructured films obtained through sol-gel synthesis are discussed. Experimental methods include microscopy (confocal, AFM) and small angle neutron scattering ... |
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| Structure-Scavenging Abilities of Cyclodextrin-Based Polyurethanes |
JUL 2002 |
40 pages |
| Authors:
Sandra K. Young; Peter L. Vajda; Eugene Napadensky; Dawn M. Crawford; James M. Sloan; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| Cyclodextrins are ring-shaped molecules containing an apolar cavity with a diameter 4-8 A wide and approximately 8 A deep. Because of the hydrophilic nature of the surface, the materials are readily dispersed in water. However, hydrophobic groups on the inner surface of the nanoporous molecules attract hydrophobic organics that bind noncovalently to the apolar cavity. Recently, polycyclodextrins have been developed as binders for energetic materials and as sorbants for biological ... |
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| Ferromagnetic GaMnAs/GaAs Superlattices - MBE Growth and Magnetic Properties |
03 JUN 2002 |
7 pages |
| Authors:
J. Sadowski; R. Mathieu; P. Svedlindh; M. Karlsteen; J. Kanski; POLISH ACADEMY OF SCIENCES WARSAW INSTOF PHYSICS
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| This paper presents the results of a study of the magnetic properties of Gallium Manganese Arsenide/Gallium Arsenide GaMnAs/GaAs) superlattices with magnetic GaMnAs layers of thickness between 8 and 16 molecular layers (ML) (23-45 angstroms) and with nonmagnetic GaAs spacers from 4 to 10 ML (11-28 angstroms). While previous reports state that GaMnAs layers thinner than 50 angstroms are paramagnetic in the whole Mn composition range achievable using molecular beam epitaxy ... |
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| Insight into the Formation of Ultrafine Nanostructures in Bulk Amorphous Zr(54.5)Ti(7.5)Al(10)Cu(20)Ni(8) |
NOV 2001 |
10 pages |
| Authors:
Andre Heinemann; Helmut Hermann; Albrecht Wiedenmann; Norbert Mattern; Uta Kuhn; INSTITUT FUER FESTKOEPER UND WERKSTOFFORSCHUNG DRESDEN (GERMANY)
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| Bulk amorphous Zr(54.5)Ti(7.5)Al(10)Cu(20)Ni(8) is investigated by means of small-angel neutron scattering (SANS) diffractional-scanning calorimetry (DSC) high-resolution electron microscopy (HREM) and other methods. The formation of ultrafine nonstructures in the glassy phase is observed and explained by a new model. Structural fluctuations of randomly distributed partially ordered domains grow during annealing just below the glass transition temperature by local re-ordering. During annealing the DSC gives evidence for a increasing volume fraction ... |
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| Proceedings of the Resonance Meeting. Volume 1. Transcripts |
04 JUN 2001 |
236 pages |
| Authors:
Elizabeth A. Furr; NATIONAL CENTER FOR PHYSICAL ACOUSTICS UNIVERSITY MS
|
| The Proceedings of the Resonance Meeting held May 30 to June 1, 1999 are in two volumes. Volume I of the proceedings contains verbatim transcriptions of the presentations given. This volume also contains a special appendix honoring Orson L. Anderson, Harold H. Demarest, Jr. and Ichiro Ohno for their contributions to the development of resonance techniques for determining elastic properties of solids. Volume II of these proceedings contains copies of ... |
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| RUS Studies of Crypto-Clathrates: Perfect Crystals with the Elastic Properties of Glasses |
04 JUN 2001 |
8 pages |
| Authors:
Veerle Keppens; MISSISSIPPI UNIV UNIVERSITY
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| The low-temperature thermal and elastic properties of glasses are known to be quite different from those of perfect crystals. For example the specific heat in amorphous solids is much larger than the Debye specific heat of crystals, and the thermal conductivity is considerably smaller. Some disordered crystals and quasicrystals were found to have properties very similar to those found in glasses, but remarkably, no amount of disorder introduced into a ... |
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| Building a Better Microreactor: Enzyme Catalysis in AOT/Bile Salt Reversed Micelles |
08 MAR 2001 |
|
| Authors:
Linda B. McGown; DUKE UNIV DURHAM NC DEPT OF CHEMISTRY
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 | The goal of this project is to design efficient reversed micellar microreactors for enzymatic detoxification of chemical agents. Enzymes are solubilized in aqueous pools by a detergent layer that serves as an interface to the bulk organic solvent. We have shown that trihydroxy bile salts modify the interfacial properties of AOT reversed micelles, thereby affecting the reversed micellar structure, the biological activity of entrapped enzymes and the transport of substrate ... |
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| Positive Anisotropic Group Scattering Cross Sections for Radiation Transport |
MAY 1999 |
207 pages |
| Authors:
J. M. DelGrande; AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH SCHOOL OF ENGINEERING
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| In solving the Boltzmann transport equation, most discrete ordinates codes calculate the source term by first approximating the scattering cross section using a Legendre polynomial expansion. Such expansions are insufficient when scattering is anisotropic and the Legendre expansion is truncated prematurely. This can lead to nonphysical negative cross sections, negative source terms and negative angular fluxes. While negative sources are problematic for standard discrete ordinates methods leading to poor convergence ... |
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| High Temperature Superconductivity. AIP Conference Proceedings, 483 |
JAN 1999 |
445 pages |
| Authors:
Stewart E. Barnes; Joseph Ashkenazi; Joshua L. Cohn; Fulin Zuo; MIAMI UNIV CORAL GABLES FL DEPT OF PHYSICS
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| This volume contains the proceedings of the 1999 University of Miami Conference on High Temperature Superconductivity. In addition to addressing physical properties, microscopic theory and mechanisms for high-temperature superconductivity, included are related topics (e.g., ladders, manganites, nickelates). The reader will find in this volume a series of papers discussing the most important experimental and theoretical developments as of spring 1999. Despite more than ten ... |
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| Spectroscopic Characterization of Reversed Micellar Phases for Enzymatic Reactions |
28 OCT 1998 |
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| Authors:
Linda B. McGown; DUKE UNIV DURHAM NC DEPT OF CHEMISTRY
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| We are investigating novel, reversed micellar media to serve as microreactors for enzymatic catalysis. The enzymes are solubilized in the aqueous cores of reversed micelles that are comprised of the detergent AOT and a bile salt cosurfactant. We are specifically interested in the effects of the bile salt on the reversed miceller structure, the biological activity of entrapped enzymes and the transport of substrate and products across the micellar interface. ... |
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| First Principles Calculations Using Linear Response Theory for Ferroelectrics |
17 MAR 98 |
4 pages |
| Authors:
Henry Krakauer; COLLEGE OF WILLIAM AND MARY WILLIAMSBURG VA DEPT OF PHYSICS
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| First principles density functional methods using LAPW and LAPW linear response method were applied to study the incipient ferroelectric SrTiO3. Despite similarities to BaTiO3, SrTiO3 remains paraelectric down to zero temperature, transforming instead to an antiferrodistortive structure at 105 K. As a function of wavevector, the linear response calculations show structural instabilities along the R-M-R line in the Brillouin zone, consistent with this antiferrodistortive ground state. Although a ferroelectric type ... |
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| Thermodynamics and Processing of Block Copolymers with NLO Application |
AUG 96 |
19 pages |
| Authors:
Frank S. Bates; MINNESOTA UNIV ST PAUL
|
| During this project more than one-hundred block copolymers, spanning seven different chemical combinations and numerous molecular weights and compositions, were synthesized using anionic polymerization and chemical modification techniques. Phase behavior was characterized with small-angle neutron scattering (SANS) and transmission electron microscopy, guided by dynamic mechanical spectroscopy measurements. A comprehensive picture of the phase behavior of diblock copolymers near the order-disorder transition has been established. Three new morphologies, bicontinuous with Ia3(bar)d ... |
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| Bubble Dosimeter Suitability for Nuclear Arms Control |
01 DEC 95 |
122 pages |
| Authors:
Jeremy C. Rich; Mark J. Harper; Martin E. Nelson; NAVAL ACADEMY ANNAPOLIS MD
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| The objective of this project was to investigate the feasibility of using the bubble dosimeter as an alternative to the present methods used to verify nuclear arms treaties. Because of the draw-downs of nuclear forces associated with the end of the draw-downs of nuclear forces associated with the end of the cold-war, demand has increased for an unobtrusive technology that could be used in the field by inspectors to aid ... |
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| Gordon Research Conference on Superconductivity Held at Les Diablerets, Switzerland on 17-22 September 1995 |
1995 |
13 pages |
| Authors:
GENEVA UNIV (SWITZERLAND)
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| The conference was organized into sessions with two or three talks concentrating on a specific subject. Thus we had a session on new materials focusing on the structural richness of the high temperature superconductors and the possible implications for the critical currents and future applications. We also had a session on the new class of superconducting borocarbides and on heavy fermion superconductors. Several talks addressed experiments probing the nature of ... |
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| Processing, Fabrication, Characterization and Device Demonstration of High Temperature Superconducting Ceramics |
30 JUL 94 |
27 pages |
| Authors:
Thomas S. Luhman; Ilhan A. Aksay; BOEING DEFENSE AND SPACE GROUP SEATTLE WA
|
| A detailed small-angle neutron scattering study of the vortex lattice in a single crystal of YBa2Cu307-x was made for a field of 0.5 tesla inclined at angles between 0 and 80 degrees to the crystalline c axis. The vortex lattice is triangular for all angles. For angles less than or equal to 70 degrees its orientation adjusts itself to maximize the pinning energy to densely and highly regularly spaced twin ... |
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| Proceedings of the International Workshop on Condensed Matter Theories (18th), Held at Valencia, Spain on June 1994 |
10 JUN 94 |
185 pages |
| Authors:
R. F. Bishop; UNIVERSITY OF MANCHESTER INST OF SCIENCE AND TECHNOLOGY (UNITED KINGDOM)
|
| This workshop covered various techniques in nuclear many-body problems as well as various theoretical techniques, ranging through the coupled cluster method, variational Jastrow-like approaches, parquet theory etc. Particular emphasis was placed on the technique of density functional theory (plus a little on density matrices), a wide range of applications including atomic cluster theory, inhomogeneous liquids and especially He(4), simple metals and metal surfaces. In this context, there was a special ... |
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| Ion Clusters and Exotic Plasma States |
28 FEB 94 |
39 pages |
| Authors:
V. Nardi; J. S. Brzosko; C. Powell; STEVENS INST OF TECH HOBOKEN NJ
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| The completed major parts of the three year program are upgrading of the plasma focus machines of the Stevens Tech laboratory to higher powering energy levels W1>20 kJ and W2>100 kJ, test of the scaling laws relating fluence and spectral characteristics of the ion cluster and supercluster emission to W, clarification of the leading physical processes which are characteristics of the plasma source of ion clusters and of superclusters with ... |
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| Dielectric and Related Phenomena, DRP '94 |
1994 |
173 pages |
| Authors:
ROYAL HOLLOWAY AND BEDFORD NEW COLL EGHAM (UNITED KINGDOM)
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| The conference on Dielectric and Related Phenomena was held from 12 September 1994 to 16 September 1994 in Zakopane, Poland. |
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| Phase Behavior, Structure, and Properties of Model Block Polymers |
14 OCT 93 |
15 pages |
| Authors:
Frank S. Bates; MINNESOTA UNIV MINNEAPOLIS DEPT OF CHEMICAL ENGINEERING AND MATERIALS SCIENCE
|
| This project brought together three distinct experimental methods in an integrated investigation of the phase behavior, structure and properties of block copolymers in the vicinity of the order-disorder transition. Anionic polymerization of polydiene diblock copolymers followed by catalytic hydrogenation was used to produce three classes of model saturated hydrocarbon materials. Dynamic mechanical spectroscopy and large amplitude dynamic shearing were employed to probe and manipulate, respectively, the melt state microstructure. Small ... |
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| Energy Levels and Predicted Absorption Spectra of Rare-Earth Ions in Rare-Earth Arsenides |
SEP 92 |
30 pages |
| Authors:
Donald E. Wortman; Clyde A. Morrison; HARRY DIAMOND LABS ADELPHI MD
|
| A crystal-field Hamiltonian for octahedral symmetry was used along with free-ion parameters for aqueous solution to fit the reported optical absorption spectra of Er(3+) in ErAs. Predictions showed excellent agreement with reported experimental data at so 74, and 300 K. Consequently, we used an interpolation procedure to predict the crystal-field splittings of the lower multiplets of the rare-earth ions Tb(3+) through Yb(3+) in their respective arsenide compounds. The lowest multiplet ... |
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| Characterization of Vesicle and Microemulsion Microstructures |
SEP 92 |
21 pages |
| Authors:
D. F. Evans; MINNESOTA UNIV MINNEAPOLIS OFFICE OF RESEARCH AND TECHNOLOGY TRANSFER ADMINIS TRATION
|
| We have determined micellar aggregation numbers for a number of single- and double-chain surfactants using time-resolved fluorescence quenching and small angle neutron scattering as functions of surfactant concentration, chain length and temperature. The force between dialkyldimethylammonium bromide and acetate bilayers was measured with the surface forces apparatus as a function of added salt and temperature. Using atomic force microscopy we obtained images of normal and interdigitated bilayers. We identified a ... |
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| Proceedings of the Annual Advanced Polymer Components Symposium (1st) Held in Indianapolis, IN on 20-22 February 1992 |
JUL 92 |
381 pages |
| Authors:
John J. Rusek; PHILLIPS LAB EDWARDS AFB CA
|
| Advanced propulsion concepts rely on advanced propulsion materials. The Phillips Laboratory is aggressively pursuing advanced polymeric materials for use in solid, liquid, and nuclear propulsion component applications. Traditional composite materials have high specific strengths, but suffer from high cost and labor intensive processing. The APC program is currently exploring thermotropic liquid crystal polymers. These materials have high specific strength and can be economically processed by traditional high volume routes such ... |
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| Electronic Properties of High-Tc Superconductors. The Normal and the Superconducting State of High-Tc Materials. Proceedings of the International Winter School held in Kirchberg, Tyrol on March 7 - 14, 1992 |
14 MAR 92 |
546 pages |
| Authors:
H. Kuzmany; M. Mehring; J. Fink; VIENNA UNIV (AUSTRIA)
|
| The International Winter School on Electronic Properties of High Temperature Superconductors, held between March 7-14, 1992, in Kirchberg,(Tyrol) Austria, was sixth in a series of meetings to be held at this venue. Four of the earlier meetings were dedicated to issues in the filed of conducting polymers, while the winter school held in 1990 was devoted to the new discipline of high- Tc superconductivity. This year's meeting constituted a forum ... |
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| A Fundamental Understanding of the Effects of Ceramic Processing on Product Microstructure |
15 FEB 92 |
57 pages |
| Authors:
G. G. Long; J. P. Cline; J. J. Ritter; NATIONAL INST OF STANDARDS AND TECHNOLOGY GAITHERSBURG MD CERAMICS DIV
|
| This is the final report arising from our research program involving the investigation of processing/microstructure relationships in selected ceramic systems. The first year of this program was dedicated to the development and detailed assessment of the novel neutron scattering and x-ray diffraction techniques required for the measurement of ceramic microstructure evolution as a function of sintering and chemistry. The next two years of the program were used to study several ... |
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| Non-Destructive Analysis for Hydrogen Concentrations in Materials |
31 OCT 91 |
15 pages |
| Authors:
Walter Meyer; William H. Miller; SYRACUSE UNIV NY INST FOR ENERGY RESEARCH
|
| The objective of the proposed research is to conduct several preliminary experiments to verify calculations made by these investigators that show it to be possible to non destructively and quantitatively determine hydrogen content in steel and possibly other host materials at the parts per million level (minimum level of from 100 to 1 ppm). The hydrogen analysis is based on the fact that 24 keV neutrons readily penetrate large thicknesses ... |
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| An Intermolecular H-O Potential for Methyl Rotations in Solid Nitromethane |
APR 91 |
34 pages |
| Authors:
Betsy M. Rice; S. F. Trevino; ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| A reliable determination of the (H-O) intermolecular potential by which of nitromethane interact with each other is presented. This effort is based upon a body of experimental information which is available on the crystal structure and the rotational properties of the methyl group of the molecule in the solid state. The crystal structure is known in the temperature range of 4 to 233 K. The rotational properties of the methyl ... |
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| Investigating the Structural Bases of Voltage-Gating Model Channels by Using Perfectly Aligned Multilayer Samples |
01 OCT 90 |
13 pages |
| Authors:
Huey W. Huang; RICE UNIV HOUSTON TX DEPT OF PHYSICS
|
| A uniformly aligned multilayer of membranes containing peptides has one-dimensional structural order in which the bilayers are the unit cells and preserves the orientational order of peptides relative to the plane of membrane. Our goal is to develop methods to extract these structural information, and use such methods to study the structural bases of the voltage-gating mechanisms in model channels. In the past year, we have developed the method of ... |
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| Diffraction Models, Dynamical Structure Tensors, and Electron-Phonon Interaction |
JUL 90 |
26 pages |
| Authors:
L. V. Meisel; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER WATERVLIET NY BENET LABS
|
| A coherent exposition of the theory of scattering from a dynamic lattice, which applies to the scattering of Bloch wave electrons as well as the scattering of plane waves, is presented. This is achieved by developing a generalized diffraction model, along the lines conceived by Van Hove, appropriate for the scattering of Bloch waves. The resulting diffraction model provides a basis for treating processes controlled by electron-phonon interaction in general ... |
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| Better Ceramics Through CHemistry IV. Symposium Held in San Francisco, California on April 16 - 20, 1990. Volume 180 |
20 APR 90 |
1143 pages |
| Authors:
Brian J. Zelinski; C. J. Brinker; David E. Clark; Donald R. Ulrich; MATERIALS RESEARCH SOCIETY PITTSBURGH PA
|
| Partial contents: Reaction Mechanisms and Kinetics: Sol-Gel Chemistry of Hydrogenosiliconates: The Role of Hypervalent Silicon Species; High Pressure Raman Study of the Hydrolysis Reaction of TMOS and TEOS; Molecular Architecture and its Role in Silica Sol-Gel Polymerization; Synthetic and Structural studies of Bismuth/Copper Alkoxides; Precursor Effects and Aqueous Chemistry: Molecular Structure of Metal Alkoxide Precursors; Tailored Molecular Precursors of Yttrium Oxide Using Functional Alcohol and Acetylacetone as Modifiers; and NMR ... |
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| Neutron Scattering for Materials Science. Materials Research Society Symposium Proceedings, Volume 166 |
90 |
519 pages |
| Authors:
S. M. Shapiro; S. C. Moss; J. D. Jorgensen; MATERIALS RESEARCH SOCIETY PITTSBURGH PA
|
| Neutron Scattering is by now a well-established technique which has been used by condensed matter scientists to probe both the structure and the dynamical interactions in solids and liquids. The use of neutron scattering methods in materials science research has in turn increased dramatically in recent years. The symposium was assembled to bring together scientists with a wide range of interest, including high-Tc superconducting materials, phase tranformations, neutron depth profiling, ... |
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| Low Temperature Elastic and Dielectric Properties of Incommensurate Barium Sodium Niobate |
15 DEC 89 |
47 pages |
| Authors:
W. F. Oliver; J. F. Scott; R. Nowak; E. R. Bernstein; COLORADO STATE UNIV FORT COLLINS DEPT OF CHEMISTRY
|
| We have performed dielectric and Brillouin spectroscopic measurements on incommensurate (IC) Ba(2)NaNb(5)O(15) from ca. 15 K to room temperature and have related our measurements to earlier studies of birefringence and x-ray and neutron crystallography, with special emphasis upon the structural phase transition near 105 K and 40 K. The 105 K transition is from Ccm2(1) to a modulated structure, which appears to be a reentrant phase also found at atmospheric ... |
|
| Materials Research Society Symposium on the Electrical, Optical and Magnetic Properties of Organic Solid State Materials Held in Boston Massachusetts on 27 November-2 December 1989 |
DEC 89 |
753 pages |
| Authors:
Long Y. Chiang; MATERIALS RESEARCH SOCIETY PITTSBURGH PA
|
| Session topics included: Beam-solid interactions -- Physical phenomena; In-situ patterning -- Selective area deposition and etching; Atomic scale structure of interfaces; Layered structures -- Heteroepitaxy, superlattices, strain and metastability; Properties of II-VI semiconductors -- Bulk crystals, epitaxial films, Quantum well structures, and dilute magnetic systems; Diamond, boron nitride, silicon carbide and related wide bandgap semiconductors; Impurities, defects and diffusion in semiconductors -- Bulk and layered structures; Materials issues in microcrystalline ... |
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| Studies of the Structure and Properties of Amorphous a-Zr76Fe24Hx |
31 MAY 89 |
12 pages |
| Authors:
R. C. Bowman Jr.; A. J. Maeland; K. M. Unruh; E. L. Venturini; J. J. Rush; AEROSPACE CORP EL SEGUNDO CA LAB OPERATIONS
|
| The a-Zr76Fe24Hx samples with x 140 irreversibly crystallizes into c-Zr(Hx) and ZrFe2. Keywords: Zirconium alloys, Iron, Amorphous alloys, hydrogen, Thermal stability, Metal hydrides, Mossbauer effect, Nuclear magnetic resonance, Glassy alloys. (AW) |
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| Structure, Potential Energy Surfaces and Thermodynamic Properties of Hydroxylammonium Nitrate |
APR 89 |
8 pages |
| Authors:
R. D. Murphy; F. K. Ross; MISSOURI UNIV-COLUMBIA DEPT OF PHYSICS
|
| The research performed under this contract was primarily designed to produce basic structural information about hydroxylammonium nitrate (HAN), an important ingredient in liquid propellant mixtures under development by the U.S. Army Ballistic Research Laboratory (BRL). The most important results which we have achieved are as follows: Single pure crystals of HAN were first produced by Ross and subsequently by others at BRL. X-ray and neutron diffraction measurements have been made ... |
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| Investigating the Structural Bases of Voltage-Gating Model Channels by Using Perfectly Aligned Multilayer Samples |
20 SEP 88 |
8 pages |
| Authors:
Huey W. Huang; RICE UNIV HOUSTON TEX DEPT OF PHYSICS
|
| One dimensional quasi crystals of perfect multilayers, in which ion channels are uniformly oriented within parallel membranes, can be used to study the structural base of channel conductivities. We have developed 1) the techniques for preparing such multilayer samples and 2) the spectroscopic methods (circular dichroism and x-ray diffraction) for extracting structural information from these samples. The sample variables include electric field, water content, ion concentrations, etc. We have observed ... |
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| Molecular Beam Studies of Surface Phonons and Gas Surface Interactions |
15 JUN 88 |
5 pages |
| Authors:
Steven J. Sibener; CHICAGO UNIV IL
|
| Angle and velocity resolved inelastic helium scattering is becoming an incisive tool for probing the vibrational characteristics of clean and adsorbate covered surfaces. These experiments can be visualized as being a two- dimensional (i.e., surface sensitive) analog to inelastic neutron scattering, which has played such a crucial role in elucidating the nature of elementary excitations in bulk crystals. In this paper a general review is presented of our recent work ... |
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| Study of High Temperature Failure Mechanisms in Ceramics |
JUN 88 |
68 pages |
| Authors:
Richard A. Page; James Lankford; SOUTHWEST RESEARCH INST SAN ANTONIO TEX DEPT OF MATERIALS SCIENCES
|
| This report summarizes the results of a fundamental study involving experimental characterization and analytical modeling of grain boundary cavitation and creep crack growth in structural ceramics exposed to pure tensile loading. The major experimental techniques employed in the program are the use of small-angle neutron scattering to characterize cavity nucleation and growth and stereoimaging analysis to characterize the stress and strain fields associated with growing creep cracks. The major accomplishments ... |
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| Spatial Organization of Homopolymer Chains Inside Spherical Polybutadiene Domains of SB Diblock Copolymers |
16 MAR 88 |
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| Authors:
P. Cheng; C. V. Berney; R. E. Cohen; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CHEMICAL ENGINEERING
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| Blends of perdeuterated polybutadiene homopolymer and a polystyrene- polybutadiene diblock copolymer were prepared by solution casting techniques. Small angle neutron scattering and transmission electron microscopy experiments on blends containing homopolymer with chain length smaller than the corresponding block sequence showed that homopolymer chains are solubilized by the spherical microdomains up to a homopolymer content of about 15 mole percent. The solubilized homopolymer is distributed in a spatially uniform manner throughout ... |
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| Helical Lattice Vibrational Modes in DNA |
10 MAR 88 |
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| Authors:
V. V. Prabhu; W. K. Schroll; L. L. Van Zandt; Earl W. Prohofsky; PURDUE UNIV LAFAYETTE IND DEPT OF PHYSICS
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| We show that the acoustic branches calculated by our helical lattice dynamics calculations can match the observed inelastic neutron scattering results. The fit in the neutron sub Terrahertz region is consistent with our fit to Brillouin results in the Gegahertz region when the frequency dependence of the dielectric constant of water is taken into account. |
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| Distribution of Chain Ends Inside the Polybutadiene Microspheres of SB Diblock Copolymers |
28 JAN 88 |
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| Authors:
P. Cheng; C. V. Berney; R. E. Cohen; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CHEMICAL ENGINEERING
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| Two polystyrene polybutadiene block copolymers were examined in small angle neutron scattering (SANS) experiments designed to probe the location of the polybutadiene chain ends inside the polybutadiene microspheres of these specimens. One of the copolymers, SBm, was phase-matched; the B moiety was synthesized using a suitable mixture of deutero and normal butadiene monomer. The other copolymer, SBmBd, contained short perdeuterated polybutadiene sequences at the end of the polybutadiene block of ... |
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| Physics of Gels with Short Bond Lifetimes |
30 SEP 87 |
6 pages |
| Authors:
H. E. Stanley; BOSTON UNIV MA CENTER FOR POLYMER STUDIES
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| We have performed detailed Raman spectroscopic measurements to study the structure of liquid water in the normal and supercooled temperature range. Experiments have been performed in the high frequency OH stretching vibration region and in the very low frequency intermolecular H-bond stretching vibration region. Our results from the high frequency region have shown that at low temperatures most of the OH bonds are strongly H-bonded and that the distribution of ... |
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| Proceedings of the Annual Conference on Magnetism and Magnetic Materials (31st) Held in Baltimore, Maryland on 17-20 November 1986. Part B |
15 APR 87 |
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| Authors:
N. C. Koon; J. D. Adam; I. A. Beardsley; D. L. Huber; AMERICAN INST OF PHYSICS NEW YORK
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| Partial Contents: Magnetoelastic Excitations and Applications; Thin Film Recording Media; Soft Magnetic Materials; Particulate Recording Media; Symposium on Heavy Fermions; Numerical Methods; Critical Phenomena, One- Dimensional Systems and Randomness; Alloys and Intermetallic Compounds II; Magnetic Recording Phenomena; Magnetic Multilayers; Spin Glasses; Symposium on Microwave/mm Magnetics for Integrated Circuits; Magnetic Excitations and Applications; Recording Heads; Domain Walls and Magnetization Processes; Spin- Glass Panel; Alloys and Intermetallic Compounds I; Thin Films and ... |
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Reports by Keyword(s)
NEUTRON SCATTERING
