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Displaying 851 - 875 of 1896

Controlling Thermochromism in a Photonic Block Copolymer Gel

September 26, 2012
Author(s)
Joseph J. Walish, Yin Fan , Andrea Centrone, Edwin L. Thomas
Controlling the color via temperature-induced changes of self-assembled photonic materials is important for their application in sensors and displays. The thermochromic behavior of a PS-P2VP photonic gel was studied (UV-VIS, FTIR) and found to originate

Anomalous Friction in Suspended Graphene

September 20, 2012
Author(s)
Alexander Y. Smolyanitsky, Jason P. Killgore
Since the discovery of the Amonton's law and with support of modern tribological models, friction between surfaces of three-dimensional materials is known to generally increase when the surfaces are in closer contact. Here, using molecular dynamics

UV-induced photochemical transformations of citrate capped silver nanoparticle suspensions

September 14, 2012
Author(s)
Justin M. Gorham, Robert I. MacCuspie, Kate L. Klein, D H. Fairbrother, Richard D. Holbrook
Due to the increasing use of silver nanoparticles (AgNPs) in consumer products, it is essential to understand how variables, such as light exposure, may change the physical and chemical characteristics of AgNP suspensions. To this end, the effect of 300 nm

Observation of spin-valve effect in Alq3 using a low work function metal

September 7, 2012
Author(s)
Hyuk-Jae Jang, Kurt Pernstich, David J. Gundlach, Oana Jurchescu, Curt A. Richter
We present the observation of magnetoresistance in Co/Ca/Alq3/Ca/NiFe spin-valve devices. Thin Ca layers contacting 150 nm thick Alq3 enable the injection of spin-polarized electrons into Alq3 due to engineering of the band alignment. The devices exhibit

Vertically Segregated Structure and Properties of small molecule-polymer blend semiconductors for organic thin film transistors

August 27, 2012
Author(s)
Nayool Shin, Dean DeLongchamp, Jihoon Kang, Regis J. Kline, Lee J. Richter, Vivek Prabhu, Balaji Purushothamanc, John E. Anthony, Do Y. Yoon
The phase-segregated structure and the electrical properties of thin film blends of the small-molecule semiconductor fluorinated 5,11-bis(triethylsilylethynyl) anthradithiophene with insulating binder polymers were studied for organic thin film transistor

Microwave measurements and systematic circuit-model extraction of nanowire metal semiconductor field-effect transistors

August 24, 2012
Author(s)
Dazhen Gu, Thomas M. Wallis, Pavel Kabos, Paul T. Blanchard, Kristine A. Bertness, Norman A. Sanford
We present detailed on-wafer scattering parameter measurements and equivalent circuit modeling of metal semiconductor field effect transistor (MESFET) that incorporates a GaN nanowire (NW). A systematic procedure is established to extract intrinsic model

Contact resistance of low-temperature carbon nanotube vertical interconnects

August 20, 2012
Author(s)
Ann C. Chiaramonti Debay, Sten Vollebregt, R. Ishihara, Hugo Schellevis, Kees Beenakker
In this work the electrical contact resistance and length dependant resistance of vertically aligned carbon nano- tubes (CNT) grown at 500 °C with high tube density (1011) are investigated by measuring samples with different CNT lengths. From scanning

INVESTIGATING THE MECHANISM OF ENZYME-CATALYZED RING-OPENING COPOLYMERIZATIONS

August 19, 2012
Author(s)
Matthew T. Hunley, Fahriye N. Sari, Kathryn L. Beers
As the research interest in degradable polymers has risen, an ever increasing number of manuscripts report the synthesis of copolymers through ring-opening copolymerization techniques. However, the mechanism of copolymerization remains unexplored. In

Using Viscosity Modifiers to Reduce Effective Diffusivity in Mortars

August 1, 2012
Author(s)
Kenneth A. Snyder, Dale P. Bentz, Jeffrey M. Davis
Three viscosity modifiers (a commercial shrinkage-reducing admixture, a polypropylene glycol, and cellulose ether) are used to reduce the effective diffusivity of chloride ions through mortars during a one-year exposure. Two delivery mechanisms were

Viscoelastic and poroelastic relaxations of polymer-loaded hydrogels

July 5, 2012
Author(s)
Blessing Deeyaa, Christopher Stafford, Edwin Chan, Peter M. Johnson
In this work, we study the viscoelastic and poroelastic contributions on the relaxation behavior of a polymer-loaded hydrogel using a recently develop Poroelastic Relaxation Indentation (PRI) measurement technique. By applying a generalized relaxation

THE ROLE OF TOOTH ENAMEL MECHANICAL PROPERTIES IN PRIMATE DIETARY ADAPTATION

June 27, 2012
Author(s)
Paul Constantino, James J. Lee, Yvonne Gerbig, Adam Hartstone-Rose, Mauricio Talebi, Brian R. Lawn, Peter Lucas
Primate teeth adapt to the physical properties of foods in a variety of ways including changes in occlusal morphology, enamel thickness, and overall size. We conducted a comparative study of extant primates to examine whether their teeth also adapt to

RESONANCE ENERGY TRANSFER AS A TOOL FOR PROBING INTERFACE FORMATION IN NANOCOMPOSITES

June 24, 2012
Author(s)
Mauro Zammarano, Edward D. McCarthy, Douglas M. Fox, Paul H. Maupin, Li Piin Sung, Yeon S. Kim
One of the most enduring problems in the evolution of science and technology using nanoscale materials is the characterization of their morphology in macroscopic systems.1 This involves spatial and orientation distribution, which may be multimodal and

Solid-Phase Synthesis of Ammonium Ionenes

June 24, 2012
Author(s)
Matthew T. Hunley, Kathryn L. Beers
Ionenes are polyelectrolytes with the charge along the polymer backbone. These polymers possess a precisely-defined charge density, making them ideal as physical crosslinkers for high performance elastomers as well as gene transfection agents. However

Synthesis and characterization of model crosslinked polyamide films for water purification

June 24, 2012
Author(s)
Peter M. Johnson, Edwin Chan, Jun Y. Chung, Junghyun Lee, Christopher Stafford
Reverse osmosis (RO) and nanofiltration (NF) membranes are comprised of a dense active layer supported by a porous support. Commercial active layer are highly crosslinked polyamides that are formed through interfacial polymerization directly on the support

Photo-induced Surface Transformation of Silica Nanocomposites

June 22, 2012
Author(s)
Justin M. Gorham, Tinh Nguyen, Coralie Bernard, Deborah S. Jacobs, Richard D. Holbrook
The physicochemical, UV-induced surface modifications to silica nanoparticle (SiNP) - epoxy composites have been investigated. The silica nanocomposites (SiNCs) were prepared using a two-part epoxy system with 10 % mass fraction of SiNPs and exposed to

Physical Model for Random Telegraph Noise Amplitudes and Implications

June 12, 2012
Author(s)
Richard G. Southwick, Kin P. Cheung, Jason P. Campbell, Serghei Drozdov, Jason T. Ryan, John S. Suehle, Anthony Oates
Random Telegraph Noise (RTN) has been shown to surpass random dopant fluctuations as a cause for decananometer device variability, through the measurement of a large number of ultra-scaled devices [1]. The most worrisome aspect of RTN is the tail of the

Tensile behavior of single PPTA fibers measured by the Kolsky bar using the direct fiber clamping method

June 11, 2012
Author(s)
Jae Hyun Kim, Nathanael A. Heckert, Stefan D. Leigh, Haruki Kobayashi, Walter G. McDonough, Richard L. Rhorer, Kirk D. Rice, Gale A. Holmes
The Kolsky bar test has been widely used in measuring material behavior under high strain rate conditions. In particular, this methodology has been used to characterize the high strain rate behavior of polymer and polymer composites during ballistic impact
Displaying 851 - 875 of 1896
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