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Displaying 501 - 525 of 1922

Comparison of CBED and ABF Atomic Imaging for GaN Polarity Determination

November 8, 2016
Author(s)
Alexana Roshko, Matthew D. Brubaker, Paul T. Blanchard, Kristine A. Bertness, Todd E. Harvey, Igor Levin, R.H. Geiss
A comparison of two electron microscopy techniques used to determine the polarity of GaN nanowires is presented. The techniques are convergent beam electron diffraction (CBED) in TEM mode and annular bright field (ABF) imaging in aberration corrected STEM

Calibration of Effective Tunneling Bandgap in GaAsSb/InGaAs for improved TFET Performance Prediction

November 3, 2016
Author(s)
Quentin Smets, Anne S. Verhulst, Salim El Kazzi, David J. Gundlach, Curt A. Richter, Anda Mocuta, Nadine Collaert, Aaron Thean, Marc Heyns
The effective bandgap for heterojunction band-to-band tunneling (Eg,eff) is a crucial design parameter for heterojunction TFET. However, there is significant uncertainty on Eg,eff, especially for In0.53Ga0.47As/GaAs0.5Sb0.5. This makes TFET performance

Smoldering and Flame Resistant Textiles via Conformal Barrier Formation

November 2, 2016
Author(s)
Mauro Zammarano, Shonali Nazare, John R. Shields, Kathleen M. Hoffman, Rick D. Davis
A durable and flexible silicone-based backcoating (halogen and formaldehyde free) is applied to the backside of an otherwise smoldering-prone and flammable fabric. When exposed to fire, cyclic siloxanes (produced by thermal decomposition of the backcoating

Self-Assembly of Polymer-Grafted Nanoparticles in Solvent-free Conditions

October 31, 2016
Author(s)
Alexandros Chremos, Jack F. Douglas
The grafting of polymer chains onto the surface of spherical nanoparticles leads to a hybrid type of fluid that exhibits properties of both particle suspensions and melts of star polymers – these properties being controlled by the relative dimensions of

Gas Uptake of 3-D Printed Acrylonitrile Butadiene Styrene (ABS) Using a Vacuum Apparatus Designed for Absorption and Desorption Studies

October 25, 2016
Author(s)
Makfir Sefa, Zeeshan Ahmed, James A. Fedchak, Nikolai Klimov, Julia Scherschligt
We describe a vacuum apparatus for determining the outgassing rate into vacuum, the diffusion coefficient, and the amount of gas absorbed for various materials. The diffusion coefficient is determined from a model applied to time-dependent desorption data

Nanoscale Pillar-enhanced Tribological Surfaces as Antifouling Membranes

October 24, 2016
Author(s)
Edwin P. Chan, Wansuk Choi, Won-Gi Ahn, Jong-Hyun Park, Hyun W. Jung, Seungkwan Hong, Ji-Young Han, Sangpil Park, Doo-Hyun Ko, Jung-Hyun Lee
We present a nonconventional membrane surface modification approach that utilizes surface topography to manipulate the tribology of foulant accumulation on water desalination membranes via imprinting of submicron titanium dioxide (TiO2) pillar patterns

An Investigation of the Temperature and Strain-Rate Effects on Strain-to-Failure of UHMWPE Fibers

October 18, 2016
Author(s)
Don Jenket II, Amanda L. Forster, Nicholas G. Paulter Jr., Tusit Weerasooriya, Carey A. Gunnarsson, Mohamad Al-Sheikhly
During a ballistic impact, Ultra High Molecular Weight Polyethylene (UHMWPE) fibers are subjected to high temperatures and high strain-rates. Their tensile strength increases with increasing strain-rate and decreases with increasing temperature. To

Identification of the Crystal Symmetry in 1T' MoTe2 with Polarization-Resolved Second Harmonic Generation and Raman Scattering

October 13, 2016
Author(s)
Ryan Beams, Luiz Gustavo Cancado, Sergiy Krylyuk, Irina Kalish, Berc Kalanyan, Arunima Singh, Kamal Choudhary, Patrick Vora, Francesca M. Tavazza, Albert Davydov, Stephan J. Stranick
We study the crystal symmetry properties of few-layer 1T' MoTe2 using the polarization dependence of the second harmonic generation (SHG) and Raman scattering. Bulk 1T' MoTe2 is know to be inversion symmetric, however, we nd that the inversion symmetry is

The rheo-Raman microscope: Simultaneous chemical, conformational, mechanical, and microstructural measures of soft materials

October 4, 2016
Author(s)
Anthony P. Kotula, Matthew Meyer, Francesca De Vito, Jan Plog, Angela R. Hight Walker, Kalman D. Migler
We describe the design and demonstrate performance of an instrument capable of simultaneous Raman spectroscopy, rheology, and optical microscopy of materials. The instrument couples a Raman microscope with a rotational rheometer through an optically

Rapid and Accurate C-V Measurements

October 1, 2016
Author(s)
Jihong Kim, Pragya Shrestha, Jason Campbell, Jason Ryan, David M. Nminibapiel, Joseph Kopanski, Kin P. Cheung
We report a new technique for the rapid measurement of full capacitance-voltage (C-V) characteristic curves. The displacement current from a 100 MHz applied sine-wave, which swings from accumulation to strong inversion, is digitized directly using an

Compliance-Free Pulse Forming of Filamentary RRAM

September 30, 2016
Author(s)
Pragya Shrestha, David M. Nminibapiel, Jihong Kim, Helmut Baumgart, Kin (Charles) Cheung, Jason Campbell
Despite the overwhelming effort to improve the efficacy of resistive random access memory (RRAM), the underlying physics governing RRAM operation have proven elusive. A survey of the recent literature almost universally indicates that the remaining glaring

Raman spectroscopy based measurements of carrier concentration in n-type GaN nanowires grown by plasma-assisted molecular beam epitaxy

September 30, 2016
Author(s)
Lawrence H. Robins, Elizabeth Horneber, Norman A. Sanford, Kristine A. Bertness, John B. Schlager
The carrier concentration in ensembles of n-type GaN nanowires (NWs) grown by plasma-assisted molecular beam epitaxy was determined by curve-fitting analysis of Raman spectra, based on modeling of the carrier concentration dependence of the longitudinal

Volume Determination of Irregularly-shaped Quasi-spherical Nanoparticles

September 22, 2016
Author(s)
Ravikiran Attota
Nanoparticles (NPs) are widely used in diverse application areas, such as medicine, engineering, and cosmetics. The size (or volume) of NPs is one of the most important parameters for their successful application. It is relatively straightforward to

Signatures of intracrystallite and intercrystallite limitations of charge transport in polythiophenes

September 20, 2016
Author(s)
Kiarash Vakhshouri, Brandon Smith, Edwin Chan, Chenchen Wang, Alberto Salleo, Cheng Wang, Alexander Hexemer, Enrique Gomez
Charge carrier mobilities in conjugated semicrystalline polymers depend on morphological parameters such as crystallinity, crystal orientation, and connectivity between ordered regions. Despite recent progress in the development of conducting polymers, the

A Q-band free-space characterization of carbon nanotube composites

September 19, 2016
Author(s)
Ahmed M. Hassan, Jan Obrzut, Edward Garboczi
We present a free-space measurement technique for non-destructive non-contact electrical and dielectric characterization of nano-carbon composites in the Q-band frequency range of 30 GHz to 50 GHz. The experimental system and error correction model

Film morphology evolution during solvent vapor annealing of highly efficient small molecule donor/acceptor blends

September 15, 2016
Author(s)
Sebastian Engmann, Hyun W. Ro, Andrew Herzing, Chad R. Snyder, Lee J. Richter, Paul Geraghty, David Jones
Solution-processable small molecule photovoltaics based on the novel molecular donor, benzodithiophene terthiophene rhodamine (BTR), recently have shown maximum power conversion efficiencies above 8% for active layer thicknesses up to 400 nm, using post
Displaying 501 - 525 of 1922
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