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Displaying 2001 - 2025 of 2146

Shear-Induced Structure in Polymer-Clay Nanocomposite Solutions

June 1, 2004
Author(s)
Sheng Lin-Gibson, H W. Kim, G Schmidt, Charles C. Han, Erik K. Hobbie
Abstract: The equilibrium structure and shear response of model polymer-clay nanocomposite gels are measured using X-ray scattering, light scattering, optical microscopy, and rheometry. The suspensions form physical gels via the bridging of neighboring

Stresses in shape memory polymer-matrix nanocomposites for biomedical applications

June 1, 2004
Author(s)
Davor Balzar, G Stefanic, Kenneth Gall, Martin Dunn, Yiping Liu
We report on the residual stresses in amorphous shape memory polymers reinforced with SiC particles. After 50 % compression of the composite material at 25 ¿C, the SiC particles exhibit a compressive stress, which is almost completely released during

In-situ Soft X-ray Studies of Toluene Catalytic Oxidation on the Pt(111) Surface

January 5, 2004
Author(s)
A L. Marsh, D J. Burnette, Daniel A. Fischer, J L. Gland
The catalytic oxidation of toluene on the Pt(111) surface has been characterized, in flowing oxygen pressures up to 1.33 Pa, using fluorescence yield near-edge spectroscopy (FYNES). During temperature-programmed (TP-FYNES) oxidationexperiments in flowing

Residual stress determination by diffraction: Modeling and applications

January 1, 2004
Author(s)
Davor Balzar, N C. Popa
Residual stress plays an important role in shaping Iilaterials properties. We present both the method to determine texture-weighted strain orientation distribution function for arbitrary crystal and sample symmetries and an example of the determination of

Nanometrology - FY 2003 Program and Selected Accomplishments

December 15, 2003
Author(s)
Clare M. Allocca, Stephen W. Freiman
The emphasis on nanotechnology around the world is leading to the development and commercialization of unique products based upon significantly smaller devices and material ensembles. Materials at the nanoscale in three dimensions (NEMS, MEMS), two

Orientation of Platelets in Multilayered Nanocomposite Polymer Films

December 1, 2003
Author(s)
M M. Malwitz, Sheng Lin-Gibson, Erik K. Hobbie, Paul Butler, G Schmidt
The orientation of platelets in micron thick polymer-clay nanocomposite films was investigated by means of small-angle neutron scattering (SANS), small angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD). The films with various clay

Elastic Constants of Layers in Isotropic Laminates

November 1, 2003
Author(s)
F Hayliger, H M. Ledbetter, Sudook A. Kim, Ivar E. Reimanis
We determined the individual laminae elastic constants in multilayer laminates composed of dissimilar isotropic layers using acoustic resonance spectroscopy and the linear theory of elasticity. Resonant ultrasound allows one to measure the free-vibration

The 2002 Materials Research Society (MRS) Fall Meeting report

October 17, 2003
Author(s)
Winnie K. Wong-Ng
Following tradition, the 2002 Materials Research Society (MRS) annual meeting again took place from in Boston Copely Plaza from December 1 to 6 (in the spacious Hynes Convention Center). Attending the Boston MRS Fall meeting, for many attendees, has also

Combinatorial Chemistry

October 13, 2003
Author(s)
J D. Hewes, Debra L. Kaiser, Alamgir Karim, Eric J. Amis
In 1995, the rapid fabrication of tens, hundreds, and, eventually, tens of thousands of samples in two-dimensional arrays of discrete microscaled samples (pixels) using lithography methods developed for the electronics industry was reported. Importantly

Elastic Stiffnesses, Debye Temperatures, and T c in Cuprates

September 1, 2003
Author(s)
H M. Ledbetter, K Sudook
For cuprate superconductors and related oxides, we review some aspects of their elastic constants. We consider the systematics of the bulk-modulus/atomic-volume (B/V a) relationship. For nonsuperconducting oxides, the B-V a diagram shows that most oxides

Elastic Constants of Natural Quartz

August 1, 2003
Author(s)
Paul R. Heyliger, H M. Ledbetter, Sudook A. Kim
We measured the elastic constants of a natural-quartz sphere using resonance-ultrasound spectroscopy (RUS). Our measurements of the near-traction-free vibrational frequencies of the sphere are matched with the predicted frequencies from the dynamic theory
Displaying 2001 - 2025 of 2146