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A Self-Attenuating Superconducting Transmission Line for Use as a Microwave Power Limiter

June 1, 2003

Author(s)

James Booth, David A. Rudman, Ronald H. Ono

We have designed, fabricated, and tested a microwave power limiter based on high temperature superconductor thin film technology. The signal limiter takes the form of a 50 Ohm} coplanar waveguide transmission line that is reversibly driven from the low

Description of the Nonlinear Behavior of Superconductors Using a Complex Conductivity

June 1, 2003

Author(s)

James Booth, Susan A. Schima, Donald C. DeGroot

The origin of the detrimental nonlinear response in the high Tc superconductor (HTS) microwave devices is currently not well understood. In order to help elucidate the origin of these nonlinear effects, we have performed phase-sensitive measurements of the

Influence of Impedance Mismatch Effects on Measurements of Unloaded Q Factors of Transmission Mode Dielectric Resonators

June 1, 2003

Author(s)

Kenneth Leong, James Booth, Sang Y. Lee

Precise measurements of the surface resistance of high temperature superconducting thin films using transmission mode dielectric resonators requires accurate knowledge of the unloaded Q factor. So far, the most accurate method of unloaded Q factor

Microwave Surface Impedance and Nonlinear Properties of MgB 2 Films

June 1, 2003

Author(s)

James Booth, Sang Y. Lee, Kenneth Leong, J. H. Lee, J. Lim, H. N. Lee, S. H. Moon, B. Oh

We have measured the temperature dependence of the microwave surface impedance and the nonlinear response of high-quality MgB 2 films on c-cut sapphire at temperatures below 40 K. MgB 2 films with surface resistance (Rs) as low as 0.09 mOhm} at 8 K and 19

Using Self-Assembled Monolayer Technology to Probe the Mechanical Response of the Fiber Interphase-Matrix Interphase Interface

June 1, 2003

Author(s)

Gale A. Holmes, E Feresenbet, D T. Raghavan

In this paper, a brief review of the fiber-matrix interphase/interface region is given for carbon- and glass-fiber composites. The interphase/interface region is discussed interms of the fiber interphase (FI), the matrix (MI), and the FI-MI interface as

Benzene Intermediates and Mechanisms during Catalytic Oxidation on the Pt (111) Surface Using Soft X-ray Fluorescence Methods

May 15, 2003

Author(s)

A L. Marsh, D J. Burnett, Daniel A. Fischer, J L. Gland

The catalytic oxidation of benzene on the Pt(111) surface has been characterized, in pressures of flowing oxygen up to 1.33 Pa, using temperature-programmed fluorescence yield near-edge spectroscopy (TP-FYNES). During temperature-programmed oxidation

Combining Magnets and Dielectrics: Crystal Chemistry in the BaO-Fe 2 O 3 -TiO 2 System

April 1, 2003

Author(s)

T Siegrist, Terrell A. Vanderah

Phases observed in the Ba-Fe-Ti-O system are classified and described within the framework of close packed [O,Ba/O] layers, with the transition metals in either octahedral (titanium and iron) or tetrahedral (iron only) sites. The resulting crystal

Intermetallics Formation and Growth at the Interface of Tin-Based Solder Alloys and Copper Substrates

February 17, 2003

Author(s)

Juan C. Madeni, S X. Liu, Thomas A. Siewert

Increasing concerns regarding environmental contamination is driving the soldering research community to develop lead-free solder alloys. Previous studies have shown that Sn-based alloys such as Sn-3.5Ag, Sn-0.7Cu, Sn-9Zn, and Sn-3.2Ag-O.8Cu have promising

Application of the V-Notch Shear Test as Applied to Unidirectional Hybrid Composites

January 1, 2003

Author(s)

H Jianmei, Martin Chiang, Donald L. Hunston

The modified Wyoming test fixture (ASTM D5379-93) with doubly v-notched specimens was investigated as a mean for determining the in-plane shear modulus and strength of unidirectional hybrid composites. Two types of hybrid systems having different fiber-tow

Chemistry of Silanes Interfaces in Dental Polymers and Composites

January 1, 2003

Author(s)

Joseph M. Antonucci, Sabine H. Dickens, Bruce O. Fowler, H H. Xu, Walter G. McDonough

The performance and service life of glass- or ceramic-filled polymeric composites depend on the nature of their resin, filler and interfacial phases as well as the efficacy of the polymerization process. The synergy that exists between the organic polymer

Effect of Acidic Comonomers on Methacrylate Conversion and Mechancial Strength of Bioreactive Composites Based on Amorphous Calcium Phosphate

January 1, 2003

Author(s)

Joseph M. Antonucci, Walter G. McDonough, D W. Liu, Drago Skrtic

Effect of Acidic Comonomers on Methacrylate Conversion and Mechanical Strength of Bioactive Composites Based on Amorphous Calcium Phosphate

January 1, 2003

Author(s)

Joseph M. Antonucci, Walter G. McDonough, Da-Wei Liu, Drago Skrtic

Prior research utilizing a monomer system consisting of the dental monomers Bis-GMA and TEGDMA at equal masse levels with neutral, hydrophilic monomers indicated that, generally, the ternary monomer enhanced the degree of methacrylate conversion (DC) but

Glass-Fiber/Resin Interfacial Strength the Microbond Test and Chemical Evaluation

January 1, 2003

Author(s)

Walter G. McDonough, Joseph M. Antonucci, Joy Dunkers, Gary E. Schumacher

The quest for durable, aesthetic and bondable materials that can restore both the function and appearance of lost tooth structure has been a major concern for dental materials researchers. A significant advance, which ushered in the modern era of

Interaction between Matrix Cracks in E-Glass/Epoxy Two-Dimensional Multi-Fiber-Array Model Composites

January 1, 2003

Author(s)

Gale A. Holmes, Walter G. McDonough, Joy Dunkers, Charles C. Han

Subsolidus Phase Equilibria and Crystal Chemistry in the System BaO-TiO 2 -Ta 2 O 5

January 1, 2003

Author(s)

Terrell A. Vanderah, Robert S. Roth, T Siegrist, W Febo, J. M. Loezos, Winnie K. Wong-Ng

Subsolidus phase relations have been determined for the BaO: TiO 2Ta 2O 5 system. Approximately 100 specimens were prepared in air at temperatures near but below the solidus (1275 C to 1500 C). For the binary BaO: Ta 2O 5 subsystem, the formation of all

Wavelet Transform Signal Processing to Distinguish Different Acoustic Emisson Sources

January 1, 2003

Author(s)

K S. Downs, Marvin A. Hamstad, E P. Baars

A database of wideband acoustic emission (AE) modeled signals were used to continue to examine the use of wavelet transform (WT) results to accomplish identification of AE sources. The AE signals in the database were created by use of a validated three

Application of the V-Notch Shear Testing for Unidirectional Hybrid Composities

December 1, 2002

Author(s)

J He, Martin Y. Chiang, Donald L. Hunston, Charles C. Han

The v-notch (losipescu) shear test was investigated as a mean for determining the in-plane shear modulus and strength of unidirectional hybrid composites. Two types of hybrid systems having different fiber tow volume fractions composed of carbon and glass

Phase Equilibria and Crystal Chemistry in the BaO-Al 2 O 3 -Nb 2 O 5 and BaO-Nb 2 O 5 Systems

November 1, 2002

Author(s)

Terrell A. Vanderah, B C. Collins, Winnie K. Wong-Ng, Robert S. Roth, L Farber

Subsolidus phase equilibria in the BaO:Al 2O 3:Nb 2O 5 system at ~1250 C in air have been determined. Ternary compound formation in this system is limited to one new phase, Ba 5.75Al 0.75Nb 9.25O 30 (Ba 6-xAl 1-xNb9+xO30, x=0.25; P4bm (No. 100); a=12.558(1

Talking Ceramics

November 1, 2002

Author(s)

Terrell A. Vanderah

This is an invited Perspective article describing the technical needs and state-of-the-art research activities in the materials science of microwave ceramics, especially dielectric materials which serve as critical elements in resonators and filters

The Effects of Local Inhomogeneity on Shear Property Measurements of Hybrid Composites

November 1, 2002

Author(s)

Martin Chiang, Carl R. Schultesiz, J He

Numerous biological and chemical studies involve the use of calcium hydroxyapatite Ca10(PO4)6(OH)2, HA. In this study detailed physicochemical characterization of hexagonal HA prepared from an aqueous solution was carried out employing different methods

An Analysis of the Fiber-Fiber Interactions Using the Fragmentation Test and Optical Coherence Tomography

October 1, 2002

Author(s)

Walter G. McDonough, Gale A. Holmes, Joy P. Dunkers

Multi-fiber model composites are being used to conduct fundamental studies into the nucleation of failure in fibrous composites. Current results have revealed that the nucleation of critical flaws in unidirectional fibrous composites may rely on the time

Application of Self-Assembled Technology to Probe Fiber Matrix-Adhesion

October 1, 2002

Author(s)

E Feresenbet, D T. Raghavan, Gale A. Holmes

Adhesion at the fiber-matrix interface of composite is often related to a combination of factors such as mechanical interlocking, physico-chemical interactions, and chemical bonding of the fiber-matrix interphase region. We demonstrate the use of (self

Application of an On-Line Weld Monitoring System

September 12, 2002

Author(s)

Thomas A. Siewert, Ivan Samardzic, Stefanija Klaric

quisition analysis and real-time manipulation of the welding parameters offer added controls over the weld quality. Thanks to the continual development of information technology and electronics, it is possible to improve the systems for monitoring of the

Acoustic Spectroscopy of Lithium Niobate: Elastic and Piezoelectric Coefficient

September 1, 2002

Author(s)

H Ogi, Y Kawashima, M Hirao, H M. Ledbetter

We report the first Simultaneous measurement of a crystal's complete elastic and piezoelectric coefficients: C if, e ijk. The studied crystal was lithium niobate (LiNbO 3) with trigonal crystal symmetry (3 m point group), thus six independent C ijk, four e

Rheology of Poly(ethylene oxide) Clay Solutions

August 1, 2002

Author(s)

Sheng Lin-Gibson, G Schmidt, Jai A. Pathak, Charles C. Han

Poly(ethylene oxide) and Laponite, a synthetic hectorite clay, form highly viscoelastic solutions in water. Above a certain clay concentration, these solutions can be described as physical crosslinked networks where clay platelets undergo equilibrium