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Displaying 376 - 400 of 806

Spin Waves in Detwinned BaFe 2 As 2

August 8, 2018
Author(s)
Xingye Lu, Daniel D. Scherer, David W. Tam, Wenliang Zhang, Rui Zhang, Huiqian Luo, Leland Harriger, H. C. Walker, D.T. Adroja, Brian M. Andersen, Pengcheng Dai

Highly Contrasting Static Charging and Bias Stress Effects in Pentacene Transistors with Polystyrene Heterostructures Incorporating Oxidizable N,N'-Bis(4-Methoxyphenyl)aniline Side Chains as Gate Dielectrics

August 1, 2018
Author(s)
Qingyang Zhang, Tejaswini S. Kale, Evan Plunkett, Wei Shi, Brian Kirby, Daniel H. Reich, Howard E. Katz
Charge trapping and storage in polymer dielectrics can be harnessed for the control of semiconductor device behavior, including organic transistors. For example, gate insulators chosen for organic transistors have an important effect on both bias stress

Aggregation and Solubility of a Model Conjugated Donor-Acceptor Polymer

July 31, 2018
Author(s)
Daniel R. Reid, Nicholas E. Jackson, Alexander J. Bourque, Chad R. Snyder, Ronald L. Jones, Juan de Pablo
In organic semiconductors, solution-phase polymer structure and aggregation have a strong influence on device morphology and performance. Thus, understanding solubility of conjugated polymers is crucial for their rational design. Using a combination of

Do Very Small POSS Nanoparticles Perturb s-PMMA Chain Conformations?

July 21, 2018
Author(s)
Nicolas Jouault, Sanat K. Kumar, Robert J. Smalley, Changzai Chi, Robert Moneta, Barbara Wood, Holly Salerno, Yuri B. Melnichenko, Lilin He, William E. Guise, Boualem Hammouda, Michael K. Crawford
Small-Angle Neutron Scattering (SANS) measurements of polymers mixed with weakly attractive 1.0 nm diameter polyhedral oligomeric silsesquioxane (POSS) nanoparticles (NPs) show no observable changes in the chain radius of gyration R g, regardless of the

Effect of temperature on the structure and dynamics of triblock copolymer coacervate hydrogels

July 16, 2018
Author(s)
Vivek M. Prabhu, Ryan C. Nieuwendaal, Anand Rahalkar, Juan J. DePablo, Samanvaya Srivastava, Matthew Tirrell
Triblock copolymer coacervate gels were characterized by small-angle neutron scattering (SANS) and dynamic light scattering. The oppositely charged polyelectrolyte complex core size does not change with temperature. However, the neutral middle block that

Nature of Decahydro-Closo-Decaborate Anion Reorientations in an Ordered Alkali-Metal Salt: Rb 2 B 10 H 10

July 12, 2018
Author(s)
Mirjana NMN Dimitrievska, Vitalie Stavila, Alexei V. Soloninin, Roman V. Skoryunov, Olga A. Babanova, Hui Wu, Wei Zhou, Wan Si Tang, Antonio Faraone, Jacob Daniel Tarver, Benjamin Trump, Alexander V. Skripov, Terrence J. Udovic
The ordered monoclinic phase of the alkali-metal decahydro-closodecaborate salt Rb 2B 10H 10 was found to be stable from about 250 K all the way up to an order-disorder phase transition temperature of approximately equal} 762 K. The broad temperature range

Universal Geometric Frustration in Pyrochlores

July 5, 2018
Author(s)
Benjamin A Trump, Syed M. Koohpayeh, Ken J. T. Livi, JiaJia Wen, Kathyrn Arpino, Quentin M. Ramasse, Rik Brydson, Mikhail Feygenson, H. Takeda, M. Takigawa, K. Kimura, S. Nakatsuji, Collin L. Broholm, T. M. McQueen
We report on the structural details of Pr 2Zr 2O 6O', La 2Zr 2O 6O', and Yb 2Ti 2O 6O' in the A 2B 2O 6O' pyrochlore structure. X-ray and neutron powder diffraction indicate these materials are long-range ordered. On the local scale these materials appear

Spin-Phonon Couplings in Transition Metal Complexes with Slow Magnetic Relaxation

July 3, 2018
Author(s)
Duncan H. Moseley, Shelby E. Stavretis, Komalavalli Thirunavukkuarasu, Mykhaylo Ozerov, Yongqiang Cheng, Luke L. Daemen, Jonathan Ludwig, Zhengguang Lu, Dmitry Smirnov, Craig Brown, Anup Pandey, A. J. Ramirez-Cuesta, Adam C. Lamb, Mihail Atanasov, Eckhard Bill, Frank Neese, Zi-Ling Xue
Co(acac) 2(H 2O) 2 (1, acac = acetylacetonate), a model transition metal complex, displays field-induced slow magnetic relaxation as a single-molecule magnet. Raman spectra of 1, Co(acac) 2(D 2O) 2 (1-d 4 and Co(acac-d 7) 2(D 2O 2) 2 (1-d 18) reveal that

Inelastic and Deep Inelastic Neutron Spectroscopy of Water Molecules under Ultra-Confinement

July 1, 2018
Author(s)
A. I. Kolesnikov, G. F. Reiter, Timothy R Prisk, M. Krzystyniak, G. Romanelli, D. J. Wesolowski, Lawrence M. Anovitz
Water confined within sub-nanometer channels of silicate minerals presents an extreme case of confinement, where the restricted molecules are situated in channels whose diameter is not much larger than the water molecule itself. Recently, we discovered a

Proton and Ammonia Intercalation into Layered Iron Chalcogenides

June 25, 2018
Author(s)
Xiuquan Zhou, Brandon Wilfong, Sz-Chian Liou, Halyna Hodovanets, Craig Brown, Efrain E. Rodriguez
Structurally related to the iron-based superconductors, two new intercalated iron chalcogenides (H 0.5NH 3)Fe 2Ch 2 where Ch = S, Se have been prepared. By topochemical conversion, the protons were exchanged by lithium to form (Li 0.5NH 3)Fe 2Ch 2

Gas Adsorption in an Isostructural Series of Pillared Coordination Cages

June 21, 2018
Author(s)
Eric J. Gosselin, Gregory R. Lorzing, Benjamin Trump, Craig Brown, Eric D. Bloch
The synthesis and characterization of six novel pillared metal-organic polyhedra is reported. By utilizing dabco (1,4-diazabicyclo[2.2.2.]octane), a pillar with increased basicity as compared to typical pillars such as pyrazine, three new stable copper

Design of an Octo-Strain Specimen for Biaxial Tension Testing

June 18, 2018
Author(s)
Justin L Milner, Thomas H. Gnaupel-Herold
A custom biaxial testing fixture was designed to evaluate a new specimen geometry for complex loading paths. Biaxial testing is commonly used to evaluate work-hardening behavior of sheet metal in biaxial tension to study the accumulation of plastic strains

Design of an Ultrathin Cold Neutron Detector

June 11, 2018
Author(s)
A. Osovizky, Kevin N. Pritchard, Y. Yehuda-Zada, Jeffrey B. Ziegler, Louis E. Binkley, Peter NMN Tsai, Alan Keith Thompson, Nancy Hadad, George M. Baltic, M. Jackson, C. Hurlbut, Charles Majkrzak, Nicholas C. Maliszewskyj
WE describe the designs, fabrication, and performance of an energy analyzing detector package for cold neutron spectrometers at the NIST Center for Neutron Research. The detector package consists of arrays of highly oriented pyrolytic graphite crystals set

Precision determination of absolute neutron flux

June 8, 2018
Author(s)
Jeffrey S. Nico, Maynard S. Dewey, David M. Gilliam, Andrew T. Yue, Eamon Anderson, Geoff Greene, Alexander Laptev, William M. Snow
A technique for establishing the total neutron rate of a highly-collimated monochromatic cold neutron beam was demonstrated using the method of an alpha- gamma counter. The method requires only the counting of measured rates and is independent of neutron

Dynamics of Phospholipid Membranes Beyond Thermal Undulations

June 7, 2018
Author(s)
Sudipta Gupta, Judith U. De Mel, Rasangi M. Perera, Piotr Zolnierczuk, Markus Bleuel, Antonio Faraone, Gerald J. Schneider
We investigated the molecular dynamics of unilamellar lipsomes by neutron spin echo spectroscopy. We report the first experimental evidence of a short-range motion at the length-scale of the size of the head group of a lipid. The associated mean square
Displaying 376 - 400 of 806