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Displaying 1151 - 1175 of 1856

Quantitative Measurement of the Polydispersity in the Extent of Functionalization of Glass Forming Resorcinarenes

May 1, 2009
Author(s)
William E. Wallace, Kathleen M. Flynn, Charles M. Guttman, David L. VanderHart, Vivek M. Prabhu, Anuja De Silva, Nelson Felix, Christopher K. Ober
The polydispersity in the degree of functionalization for two calix[4]resorcinarenes was determined by measuring their molecular mass distribution with matrix-assisted laser desorption/ionization time of flight mass spectrometry. A mathematical method for

In-plane bias in a patterned ferromagnetic/antiferromagnetic bilayer

April 30, 2009
Author(s)
Yury P. Kabanov, Valerian I. Nikitenko, Oleg A. Tikhomirov, William F. Egelhoff Jr., Alexander J. Shapiro, Robert D. Shull
Exchange bias in bi- and multilayer magnetic systems is usually ascribed to the existence of transient magnetic structures at the interfaces between adjacent layers. Here, we report the observation of a similar phenomenon in the lateral direction

Random Telegraph Noise in Highly Scaled nMOSFETs

April 26, 2009
Author(s)
Jason P. Campbell, Jin Qin, Kin P. Cheung, Liangchun (. Yu, John S. Suehle, A Oates, Kuang Sheng
Recently 1/f and random telegraph noise (RTN) studies have been used to infer information about bulk dielectric defects' spatial and energetic distributions. These analyses rely on a noise framework which involves charge exchange between the inversion

Robust, conductive ordered mesoporous films based on carbon-silica composites

April 22, 2009
Author(s)
Lingyan Song, Dan Feng, Casey G. Campbell, Aaron M. Forster, Dongyuan Zhao, Bryan D. Vogt
Mesoporous carbon-based sensors have been demonstrated to have enhanced electrochemical response as a result of their large interfacial area. To date, mesoporous carbon powders held together by a polymeric binder have been typically utilized. However for

Impact of polymer modulus on water accumulation at polymer / metal oxide interfaces

April 1, 2009
Author(s)
Alper Karul, Kar T. Tan, Christopher C. White, Donald L. Hunston, Steve marshall, Bulent Akgun, Sushil K. Satija, Christopher Soles, Bryan D. Vogt
Ambient moisture is known to accumulate at the interface between polymers and metal oxides, leading to detrimental consequences on physical properties such as modulus and adhesion. Direct measurement of the interfacial profile has utilized neutron

Elastic and adhesive properties of alkanethiol self-assembled monolayers on gold

March 30, 2009
Author(s)
Frank W. DelRio, Cherno Jaye, Daniel A. Fischer, Robert F. Cook
Elastic and adhesive properties of alkanethiol (CH3(CH2)n 1SH) self-assembled monolayers on gold are investigated by atomic force microscopy and correlated with surface structure via near edge x-ray absorption fine structure spectroscopy. As the chain

Test Chip to Evaluate Measurement Methods for Small Capacitances

March 30, 2009
Author(s)
Joseph J. Kopanski, Muhammad Y. Afridi, Chong Jiang, Curt A. Richter
We designed and fabricated a test chip to help us evaluate the performance of new approaches to measurement of small capacitances (femto-Farads to atto-Farads range). The test chip consists of an array of metal-oxide-semiconductor capacitors, metal

Controlling the Formation and Orientation of Terraced Nanoscale Ribbons of a Thiophene-Based Copolymer

March 24, 2009
Author(s)
Dean M. DeLongchamp, Regis J. Kline, Youngsuk Jung, David Germack, Eric K. Lin, Andrew Moad, Lee J. Richter, Michael F. Toney, Martin Heeney, Iain McCulloch
Terraced nanoscale ribbon domains of a poly(2,5-bis(3-alkylthiophen-2-yl) thieno[3,2-b]thiophene) form after thin films are cooled from its highest-temperature phase. A simple flow coating procedure can induce high levels of ribbon orientation and even

Dielectric Spectroscopy Investigation of Relaxation in C60-Polyisoprene Nanocomposites

March 23, 2009
Author(s)
Yifu Ding, Sebastian Pawlus, Alexei Sokolov, Jack F. Douglas, Alamgir Karim, Christopher Soles
We investigate the influence of adding C60 nanoparticles on the dielectric relaxation spectra of both unentangled and entangled polyisoprene (PIP). Relaxation modes corresponding to both segmental and chain relaxation were analyzed over a broad temperature

Examination of thin film modulus for a series of poly(alkyl methacrylates)

March 22, 2009
Author(s)
Jessica M. Torres, Christopher Stafford, Bryan D. Vogt
In this work, the modulus of polymer thin films for a homologous series of poly(n-alkyl methacrylate)s will be discussed. In particular, the impact of the degree of undercooling from bulk Tg on the deviations will be explored as Tg is significantly

Quantifying Residual Stress in Nanoscale Thin Polymer Films via Surface Wrinkling

March 19, 2009
Author(s)
Jun Y. Chung, Thomas Q. Chastek, Michael J. Fasolka, Hyun W. Ro, Christopher Stafford
Residual stress, a pervasive consequence of solid materials processing, is stress that remains in a material after external forces have been removed. In polymeric materials, residual stress results from processes, such as film formation, that force and

Development of a Powered Outdoor Sealant Fatigue Test Apparatus

March 18, 2009
Author(s)
Christopher C. White, R. S. Williams, Steve Lacher, Corey C. Halpin
A new cyclic fatigue test apparatus (CFTA) was developed at the USDA Forest Service, Forest Products Laboratory. The new CFTA is computer-controlled and powered by electric linear actuators. Computer control allows the CFTA to subject specimens to specific

Transparency and conductivity of carbon nanotube networks

March 18, 2009
Author(s)
Jan Obrzut
The conductivity of films made of nanotubes longer than 200 nm closely follows the percolation theory for two-dimensional (2D) networks. The scaling universal exponents describing the percolation transition from an insulating to conducting state with

Singularity in the Debye-Waller factor of graphene

March 16, 2009
Author(s)
Vinod K. Tewary, B. Yang
It is shown that the Debye-Waller factor for graphene has a singularity. However, the singularity does not affect the zero-temperature value of the Debye-Waller factor. We calculate the zero-temperature limit of the mean-square displacement separately for

Adhesion Research at the National Institute of Standard and Technology (NIST)

March 11, 2009
Author(s)
Donald L. Hunston, Christopher M. Stafford
Over the years, NIST has been very active in adhesion research. Although there has never been an organizational group or large-scale program that focused specifically on this topic, a wide variety of projects have had adhesion, or related properties, as a
Displaying 1151 - 1175 of 1856