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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

A Superconducting Microwave Power Limiter for Protection of High-Performance Superconducting Electronics

July 11, 2003

Author(s)

James Booth, Kenneth Leong, Susan A. Schima

We report on the development of a microwave power limiter based on high temperature superconductor technology. The power limiter takes the form of a 50 Ω coplanar waveguide transmission line that can be reversibly driven into the normal state as microwave

Kinetic Inductance Contributions to the Nonlinear Response of Superconductors at Microwave Frequencies

July 11, 2003

Author(s)

James Booth, Kenneth Leong, Susan A. Schima

We demonstrate how nonlinear effects in high temperature superconducting thin films can be quantified based on a current-dependent penetration depth λ(J). Using an assumed form for λ(J), we calculate the expected third-order harmonic signals generated by

Formation of a Surface Quantum Dot Near Laterally and Vertically Neighboring Dots

July 1, 2003

Author(s)

B Yang, Vinod Tewary

Elastic energy release rate (EERR) of a surface quantum dot (QD) near laterally and vertically neighboring seed QDs in a linear anisotropic elastic substrate iscalculated. An efficient boundary element method is used to solve the three-dimensional boundary

The Influence of Silane Coupling Agent Composition on the Surface Characterization of Fiber and on Fiber-Matrix Interfacial Shear Strength

July 1, 2003

Author(s)

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

Epoxy resins are widely used as the matrix material for fiber reinforced composites in aircrafts, automobiles, ships and housing. Most of the reinforcement in epoxy composite is glass fiber so as to lower the cost. Studies in the past have suggested that

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