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Articles 1 - 10 of 10

Full-Text Articles in Physical Sciences and Mathematics

In Situ Infrared Evidence For The Electrochemical Incorporation Of Hydrogen Into Si And Ge, K. C. Mandal, F. Ozanam, J.-N. Chazalviel Dec 1990

In Situ Infrared Evidence For The Electrochemical Incorporation Of Hydrogen Into Si And Ge, K. C. Mandal, F. Ozanam, J.-N. Chazalviel

Faculty Publications

No abstract provided.


Degree Of Adaptive Approximation, Ronald A. Devore, Ming Yu Xiang Oct 1990

Degree Of Adaptive Approximation, Ronald A. Devore, Ming Yu Xiang

Faculty Publications

We obtain various estimates for the error in adaptive approximation and also establish a relationship between adaptive approximation and free-knot spline approximation.


Universal Scaling Of Nonlocal And Local Resistance Fluctuations In Small Wires, H. Haucke, S. Washburn, A. D. Benoit, C. P. Umbach, Richard A. Webb Jun 1990

Universal Scaling Of Nonlocal And Local Resistance Fluctuations In Small Wires, H. Haucke, S. Washburn, A. D. Benoit, C. P. Umbach, Richard A. Webb

Faculty Publications

Resistance fluctuations in small metal samples result from coherent transport of the carriers. The wave functions of the carriers extend into regions which are not accessible classically. We have directly measured the length dependence of the nonlocal magnetoresistance fluctuations in Sb and Au wires by studying regions of our samples separated from the classical current path by a distance L which varied from 3Lcphi down to 0.2Lcphi (where Lcphi is the phase coherence length for the carriers in the metal). These fluctuations decay exponentially with L/Lcphi. Measurements along the classical current paths scale more slowly …


Norms Of Positive Operators On Lp-Spaces, Ralph Howard, Anton R. Schep May 1990

Norms Of Positive Operators On Lp-Spaces, Ralph Howard, Anton R. Schep

Faculty Publications

No abstract provided.


A Scale Of Linear Spaces Related To The Lp Scale, S J. Dilworth Apr 1990

A Scale Of Linear Spaces Related To The Lp Scale, S J. Dilworth

Faculty Publications

No abstract provided.


The Extended Tracking Network And Indications Of Baseline Precision And Accuracy In The North Andes, Jeffrey T. Freymueller, James N. Kellogg Mar 1990

The Extended Tracking Network And Indications Of Baseline Precision And Accuracy In The North Andes, Jeffrey T. Freymueller, James N. Kellogg

Faculty Publications

The CASA UNO Global Positioning System (GPS) experiment (January-February 1988) included an extended tracking network which covered three continents in addition to the network of scientific interest in Central and South America. The repeatability of long baselines (400-1000 km) in South America is improved by up to a factor of two in the horizontal vector baseline components by using tracking stations in the Pacific and Europe to supplement stations in North America. In every case but one, the differences between the mean solutions obtained using different tracking networks was equal to or smaller than day-to-day rms repeatabilities for the same …


First Gps Baseline Results From The North Andes, James N. Kellogg, Jeffrey T. Freymueller, Timothy H. Dixon, Ruth E. Neilan, Clemente Ropain U., Sergio Camargo M., Benjamin Fernandez Ch., James L. Stowell, Anibal Salazar, Jaime Mora V., Luis Espin, Vernon Perdue, Leonard Leos Mar 1990

First Gps Baseline Results From The North Andes, James N. Kellogg, Jeffrey T. Freymueller, Timothy H. Dixon, Ruth E. Neilan, Clemente Ropain U., Sergio Camargo M., Benjamin Fernandez Ch., James L. Stowell, Anibal Salazar, Jaime Mora V., Luis Espin, Vernon Perdue, Leonard Leos

Faculty Publications

The CASA UNO GPS (Global Positioning System) experiment (January-February 1988) has provided the first epoch baseline measurements for the study of plate motions and crustal deformation in and around the North Andes. Two dimensional horizontal baseline repeatabilities are as good as 5 parts in 108 for short baselines (100-1000km), and better than3 parts in 108 for long baselines (>1000km). Vertical repeatabilities are typically 4 -6 cm, with a weak dependence on baseline length. The expected rate of plate convergence across the Colombia Trench is 6-8 cm/yr, which should be detectable by the repeat experiment planned for 1991. …


Central And South America Gps Geodesy- Casa Uno, James N. Kellogg, Timothy H. Dixon Mar 1990

Central And South America Gps Geodesy- Casa Uno, James N. Kellogg, Timothy H. Dixon

Faculty Publications

In January 1988, scientists from over 25 organizations in 13 countries and territories cooperated in the largest Global Positioning System (GPS) campaign in the world to date (Table 1). 43 GPS receivers collected approximately 590 station-days of data in America, Samoa, Australia, Canada, Colombia, Costa Rica, Ecuador, New Zealand, Norway, Panama, Sweden, United States, West Germany, and Venezuela. The experiment was entitled CASA UNO, an acronym for Central and South America -- and uno is the Spanish word for one, designating first epoch measurements. The CASA UNO experiment was the first civilian effort implementing a global GPS satellite tracking network. …


On Two Function-Spaces Which Are Similar To L0, S J. Dilworth, D A. Trautman Feb 1990

On Two Function-Spaces Which Are Similar To L0, S J. Dilworth, D A. Trautman

Faculty Publications

No abstract provided.


Rheology Of Aqueous Suspensions Of Polystyrene Latex Stabilized By Grafted Poly(Ethylene Oxide), Harry J. Ploehn, J. W. Goodwin Jan 1990

Rheology Of Aqueous Suspensions Of Polystyrene Latex Stabilized By Grafted Poly(Ethylene Oxide), Harry J. Ploehn, J. W. Goodwin

Faculty Publications

A water-soluble carbodiimide has been used to end-graft aminated poly (ethylene oxide)(PEO) chemically onto colloidal polystyrene particles. Two particle sizes (115 and 347 nm diameter) and two PEO molecular weights (112 000 and 615 000 g mol–1) were combined to give suspensions with four different ratios of polymer layer thickness to particle radius. Electrophoresis demonstrated that the PEO was grafted, not just adsorbed. Dynamic light scattering showed that the adsorbed and grafted layers had similar structures and that non-ionic surfactant perturbed the PEO configurations. Steady shear and oscillatory rheometry indicated that long-ranged polymeric forces between particles governed the …