363 Matching Results

Search Results

Advanced search parameters have been applied.

A Method for the Dynamic Determination of the Elastic, Dielectric, and Piezoelectric Constants of Quartz

Description: From Abstract: "Several dynamic determinations have been made of the constants of quartz. Most of these determinations do not take into account the piezoelectric effect; those that do, suffer from certain deficiencies which are discussed in this paper."
Date: June 1, 1960
Creator: Basri, Saul A.
Partner: UNT Libraries Government Documents Department

A Magnetically Controlled Quartz Fiber Microbalance

Description: Abstract: "The design, simplified techniques of construction, and uses of an electromagnetically controlled quartz fiber microbalances are described. The balance is capable of weighing directly an unbalanced load as large as 1.2 milligrams, carrying a counter-balanced load of 100 to 150 milligrams, and giving a sensitivity of 0.1 microgram per 6 minutes of arc. The one-piece all-quartz balance unit fits into a 25 millimeter diameter tube 12 centimeters long. The balance may be used under wide conditions of temperature, pressure, and reagents in completely closed systems. The balance is controlled by an external variable electromagnetic field."
Date: 1951
Creator: Edwards, Frank C. & Baldwin, Robert R.
Partner: UNT Libraries Government Documents Department

Quartz and Silica: Part 1. - General Summary

Description: Report issued by the U.S. Bureau of Mines discussing quartz and silica minerals. As stated in the foreword, "the purpose of the present paper is to assemble brief summaries of the many widely differing industries engaged in the production and preparation of these minerals in their principal commercial forms" (p. 1). This report includes tables, and illustrations.
Date: August 1931
Creator: Santmyers, Reigart Meredith
Partner: UNT Libraries Government Documents Department

Ion Beam Analysis of Microcrystalline Quartz Artifacts from the Reed Mound Site, Delaware County, Oklahoma

Description: This paper from the 23rd Conference on Application of Accelerators in Research and Industry conference proceedings evaluates the potential of particle induced X-ray emission spectrometry as a tool for future Ozarks chert provenance studies based on its ability to facilitate discrimination of Ozarks chert materials from different geological formations and identification of discrete groups of artifacts from the same geological formation.
Date: June 18, 2015
Creator: Younger-Mertz, S. B.; Manuel, J. E.; Reinert, Tilo; Szilasi, S. Z.; Hammerstedt, S. W. & Glass, Gary A.
Partner: UNT College of Arts and Sciences

Evidence for residual elastic strain in deformed natural quartz

Description: Residual elastic strain in naturally deformed, quartz-containing rocks can be measured quantitatively in a petrographic thin section with high spatial resolution using Laue microdiffraction with white synchrotron x-rays. The measurements with a resolution of one micrometer allow the quantitative determination of the deviatoric strain tensor as a function of position within the crystal investigated. The observed equivalent strain values of 800-1200 microstrains represent a lower bound of the actual preserved residual strain in the rock, since the stress component perpendicular to the cut sample surface plane is released. The measured equivalent strain translates into an equivalent stress in the order of {approx} 50 MPa.
Date: January 30, 2009
Creator: Kunz, Martin; Chen, Kai; Tamura,Nobumichi & Wenk, Hans-Rudolf
Partner: UNT Libraries Government Documents Department

Interfacial Study of Copper Electrodeposition with the Electrochemical Quartz Crystal Microbalance (EQCM)

Description: The electrochemical quartz crystal microbalance (EQCM) has been proven an effective mean of monitoring up to nano-scale mass changes related to electrode potential variations at its surface. The principles of operation are based on the converse piezoelectric response of quartz crystals to mass variations on the crystal surface. In this work, principles and operations of the EQCM and piezo-electrodes are discussed. A conductive oxide, ruthenium oxide (RuO2) is a promising material to be used as a diffusion barrier for metal interconnects. Characterization of copper underpotential deposition (UPD) on ruthenium and RuO2 electrodes by means of electrochemical methods and other spectroscopic methods is presented. Copper electrodeposition in platinum and ruthenium substrates is investigated at pH values higher than zero. In pH=5 solutions, the rise in local pH caused by the reduction of oxygen leads to the formation of a precipitate, characterized as posnjakite or basic copper sulfate by means of X-ray electron spectroscopy and X-ray diffraction. The mechanism of formation is studied by means of the EQCM, presenting this technique as a powerful in-situ sensing device.
Date: May 2005
Creator: Ojeda Mota, Oscar Ulises
Partner: UNT Libraries

Parametric Studies of Picosecond Laser-Induced Breakdown in Fused Quartz and NaCl

Description: Bulk laser-induced breakdown and self-focusing in single samples of fused quartz and NaCl were examined using picosecond optical pulses at 1.0 ym and 0.5 ym. The results of three separate but related experiments are reported. First the nonlinear index of refraction, n2, of each of the test materials is measured near the respective damage thresholds of the samples. The values of 1*2 were determined by detecting beam distortions in the far field, transmitted laser beam profile caused by the irradiance dependent index of refraction. The experimental traces were compared to theoretical beam profiles generated by a nonlinear propagation code and n2 was extracted from the resulting fits.
Date: December 1984
Creator: Williams, William Ely
Partner: UNT Libraries

Liquid-Phase Quartz Crystal Microbalance for Photovoltaics Research (Presentation)

Description: The construction of a new QCM-based flow reactor has been completed. Initial results include: (1) stable oscillation achieved with crystals sputter coated at 200 C with 500 nm ZnO; (2) sub-Hz noise level means << monolayer sensitivity; (3) Operation at elevated temperature possible after installation of membrane contactors; (4) determination of ZnO etch rates using dilute ethanolic NH{sub 4}Cl; (5) demonstration of use of an etchant as a probe of oxide-molecule interactions; (6) and use in flow rate-dependent CdS chemical deposition.
Date: May 1, 2008
Creator: Perkins, C. L. & Li, X.
Partner: UNT Libraries Government Documents Department

Quartz Crystal Microbalance Data

Description: We are using a Qpod quartz crystal microbalance (manufactured by Inficon) for use as a low-volume non-volatile residue analysis tool. Inficon has agreed to help troubleshoot some of our measurements and are requesting to view some sample data, which are attached. The basic principle of an NVR analysis is to evaporate a known volume of solvent, and weigh the remaining residue to determine the purity of the solvent. A typical NVR analysis uses 60 g of solvent and can measure residue with an accuracy of +/- 0.01 mg. The detection limit is thus (0.01 mg)/(60 g) = 0.17 ppm. We are attempting to use a quartz crystal microbalance (QCM) to make a similar measurement. The attached data show the response of the QCM as a 5-20 mg drop of solvent evaporates on its surface. The change in mass registered by the QCM after the drop evaporates is the residue that deposits on the crystal. On some measurements, the change in mass in less than zero, which is aphysical since the drop will leave behind {>=}0 mass of residue. The vendor, Inficon, has agreed to look at these data as a means to help troubleshoot the cause.
Date: November 16, 2011
Creator: Baxamusa, S H
Partner: UNT Libraries Government Documents Department

Quartz Channel Fabrication for Electrokinetically Driven Separations

Description: For well resolved electrokinetic separation, we L tilize crystalline quartz to micromachine a uniformly packe Q&iKLmnel. Packing features are posts 5 Vm on a side with:} pm spacing and etched 42 Vm deep. In addition to anisotropic wet etch characteristics for micromachining, quartz propmties are compatible with chemical soiutioits, ekctrokinetic high voltage operation, and stationary phase film depositions. To seal these channels, we employ a room temperature silicon-oxynhride deposition to forma membrane, that is subsequently coated for mechanical stability. Using this technique, particulate issues and global warp, that make large area wafer bon ding methods difficult, are avoided, and a room temperature process, in contrast to high temperature bonding techniques, accommodate preprocessing of metal films for electrical interconnect. After sealing channels, a number of macro-assembly steps are required to attach a micro-optical detection system and fluid interconnects. Keywords: microcharmel, integrated channel, micromachined channel, packed channel, electrokinetic channel, eleetrophoretic channel
Date: December 1, 1998
Creator: Arnold, D.W.; Ashby, C.I.H.; Bailey, C.G.; Kravitz, S.H., Warren, M.E. & Matzke, C.M.
Partner: UNT Libraries Government Documents Department

The Propagation and Backscattering of Soliton-Like Pulses in a Chain of Quartz Beads and Related Problems. (I). Propagation

Description: We confirm that for vanishingly small loading and large impact condition, it may be possible to generate solitons in a chain of grains that are characterized by Herkian contacts. For uniform or progressive loading conditions throughout the chain, one generates soft-solitons which are weakly dispersive in space and time. Under conditions of weak impact one generates acoustic pulses through the chain. We describe the displacements, velocities and accelerations suffered by the individual grains when subjected to solitons, soft-solitons and acoustic pulses and describe the effects of restitution on the propagating pulse.
Date: January 22, 2000
Creator: MANCIU,MARIAN; SEN,SURAJIT & HURD,ALAN J.
Partner: UNT Libraries Government Documents Department