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in subjects: "Raman Spectroscopy"

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Investigation of Structure and Properties of Low Temperature Deposited Diamond-Like Carbon Films

Electrodeposition is a novel method for fabrication of diamond-like carbon (DLC) films on metal substrates. In this work, DLC was electrochemically deposited on different substrates based on an anodic oxidation cyclization of acetylene in liquid ammonia. Successfully anodic deposition was carried out for DLC onto nickel substrate at temperatures below -40°C. Comparative studies were performed on a series of different carbon sources (acetylene, sodium acetylide, and a mixture of acetylene and… more

Date: August 2004

Creator: Pingsuthiwong, Charoendee

Item Type: Thesis or Dissertation

Partner: UNT Libraries

open access

Direct evidence for the amorphous silicon phase in visible photoluminescent porous silicon

Article on direct evidence for the amorphous silicon phase in visible photoluminescent porous silicon.

Date: June 1, 1992

Creator: Pérez, José M.; Villalobos, J.; McNeill, P.; Prasad, J.; Cheek, R.; Kelber, Jeffry A. et al.

Item Type: Article

Partner: UNT College of Arts and Sciences

open access

Interspecimen Study of Bone to Relate Macromechanical, Nanomechanical and Compositional Changes Across the Femoral Cortex of Bone

Mechanics of bone is widely studied and researched, mainly for the study of fracture. This has been done mostly on a macro scale. In this work hierarchical nature of bone has been explored to investigate bone mechanics in more detail. Flexural test were done to classify the bones according to their strength and deflection. Raman spectroscopy analysis was done to map the mineralization, collagen crosslinking changes across the thickness of the bone. Nanoindentation was done to map indentation ha… more

Date: May 2013

Creator: Nar, Mangesh

Item Type: Thesis or Dissertation

Partner: UNT Libraries

open access

FT-NMR and Raman Spectroscopic Studies of Molecular Dynamics in Liquids

NMR relaxation and Raman lineshape analysis are well known methods for the study of molecular reorientational dynamics in liquids. The combination of these two methods provides another approach to tackle the characterization of molecular dynamics in liquids. Investigations presented here include (1) NMR relaxation study of polycyclic compounds in solution, (2) the study of nitromethane reorientational dynamics using the NMR and Raman methods, and (3) Raman lineshape analysis of reorientation he… more

Date: December 1993

Creator: Wang, Kuen-Shian

Item Type: Thesis or Dissertation

Partner: UNT Libraries

open access

Molecular Dynamics in the Liquid Phase by FT-NMR, FT-IR and Laser Raman Lineshape Analysis

Nuclear magnetic resonance (NMR) provides a convenient probe for the study of molecular reorientation in liquids because nuclear spin-lattice relaxation times are dependent upon the details of molecular motion. The combined application of Raman and Infrared (IR) lineshape analysis can furnish more complete information to characterize the anisotropic rotation of molecules. Presented here are the studies of NMR relaxation times, together with Raman/IR Mneshape analysis of the solvent and temperat… more

Date: August 1988

Creator: Chen, Fu-Tseng Andy

Item Type: Thesis or Dissertation

Partner: UNT Libraries

open access

Raman studies of reorientational dynamics in liquids

Raman and/or infrared (IR) bandshape analysis to probe molecular dynamics in liquids has become a rapidly expanding field of study in recent years. Determination of spinning and tumbling diffusion constants, Dι and D⊥, which characterize the reorientation of symmetric-top moleclues has been successfully studied in a number of D6H and D3H molecules. For molecules of CV3 symmetry, however, previous attempts to extract spinning diffusion constants from Raman doubly degenerate vibrations (E mode) h… more

Date: December 1990

Creator: Wang, Shao-Pin

Item Type: Thesis or Dissertation

Partner: UNT Libraries

open access

Raman Studies of Conformational Energies and Hydrogen Bonding in Alcohols

The conformational energy differences have been determined for ethylene glycol, 2- chloroethanol, and 2,2- dichloroethanol in the neat liquid, DMSO, and H20 with Raman spectroscopy. Spectra in the 0-H valence region were utilized to determine the energy difference between interand intramolecularly hydrogen bonded species. It was found that the solvent effect on the relative stabilities of the gauche and trans rotamers of the alcohols differ significantly. The results also indicate that, unlike … more

Date: August 1982

Creator: Maleknia, Simindokht

Item Type: Thesis or Dissertation

Partner: UNT Libraries

open access

Vibrational Spectra and Potential Function of Tetrachlorocyclopropene

The laser Raman spectra of tetrachlorocyclopropene in the liquid and solid phases have been recorded and vibrational assignments are presented. These results along with root mean squared vibrational amplitudes from electron diffraction data have been employed in a normal coordinate analysis in which a 19 parameter potential function is refined. This potential function, originally expressed in terms of compliance constants, is then used to derive the corresponding conventional and relaxed force … more

Date: August 1981

Creator: Adame, I. Ernesto (Ignacio Ernesto)

Item Type: Thesis or Dissertation

Partner: UNT Libraries

open access

Temperature and spectral investigation of bulk KDP below damage using 355 nm laser irradiation

A spectral and temperature investigation of fast-grown KDP crystals under high fluence, 355 nm laser irradiation is discussed. Pump-and-probe Raman spectroscopy indicate transient changes of the vibrational spectrum. Photothermal deflection experiments provide information on the temporal behavior of the temperature change. The presence of emission in the visible and NIR spectral regions is attributed to the presence of impurities and/or defects in the crystal.

Date: October 1, 1997

Creator: Demos, S. G., LLNL

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Multiscalar measurements of turbulence-chemistry interactions in nonpremixed flames

Selected results from experiments conducted over the past several years involving simultaneous multiscalar point measurements in turbulent nonpremixed flames are reviewed in this paper. In these experiments, spontaneous Raman scattering and Rayleigh scattering measurements of the major species and temperature were combined with laser-induced fluorescence measurements of minor species. The most important feature of these experiments is that they provide detailed data on the instantaneous relatio… more

Date: December 1, 1995

Creator: Barlow, R.S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Simultaneous SO{sub 2}/NO{sub x} abatement using zeolite-supported copper. Progress report, October 1--December 31, 1993

A flow reactor is being constructed at Georgia Tech for the NO decomposition reaction. The reactor is partially complete with the construction of a flow meter/controller system and a temperature controller system in place now. The stainless steel reactor tube and the furnace have been fabricated and fit to the sub-assembly containing the temperature control devices. The reactor sampling system is under fabrication. The authors plan to purchase a GC-MS to determine the composition of the exit ga… more

Date: December 31, 1994

Creator: Mitchell, M.B. & White, M.G.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Manufacturing diamond films using copper vapour lasers

Fifty nanosecond pulses of visible light have been used to produce hard, hydrogen-free diamond-like-carbon (DLC) films at irradiances between 5 x 10{sup 8} and 5 x 10{sup 10} W/cm{sup 2} The films were characterized by a number of techniques including: Raman spectroscopy, Electron Energy Loss Spectroscopy (EELS), atomic force microscopy, and spectroscopic ellipsometry. The cost for manufacturing DLC with high average power, high-pulse repetition frequency, visible light is low enough to compete… more

Date: January 8, 1996

Creator: McLean, M., LLNL

Item Type: Article

Partner: UNT Libraries Government Documents Department

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In-situ laser Raman scattering and far infrared spectroscopy studies of corrosion-passivation phenomena in metals.

Vibrational spectroscopic and electrochemical techniques are among the most useful tools for the elucidation of corrosion-passivation phenomena in metals. The former can provide information on the structure and composition of corrosion films ''in situ'' in aqueous solution environments, while thermodynamic and kinetic information may be obtained using electrochemical techniques. In this paper, we demonstrate the application of Laser Raman Scattering (LRS) and Synchrotrons Far Infrared Reflectan… more

Date: June 28, 1999

Creator: Melendres, C. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Raman Spectroscopic and Ultrasonic Measurements to Monitor the HMX ( ) Phase Transition

The HMX {beta}-{delta} solid-solid phase transition, which occurs as HMX is heated near 170 C, is clearly linked to increased reactivity and sensitivity to initiation. Thermally damaged energetic materials (EMs) containing HMX therefore may present a safety concern. Information about the phase transition is vital to a predictive safety model for HMX and HMX-containing EMs. We report work in progress on monitoring the phase transition with real-time Raman spectroscopy and ultrasonic measurements… more

Date: October 14, 1999

Creator: GIESKE,JOHN H.; MILLER,JILL C.; RENLUND,ANITA M. & TAPPAN,ALEXANDER S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Hadamard transform spectrometry: A new analytical technique; Progress report, Second year, March 15, 1992--November 15, 1992

The document is divided into 4 parts: Hadamard transform photoacoustic spectrometry and depth profiling; Hadamard transform imaging with a 2D Hadamard encoding mask (Raman image using pararosaniline hydrochloride); Hadamard transform Raman spectrometry; and work on the growth of VO{sub 2}(s) crystals for Hadamard masking material. 13 figs, refs.

Date: November 15, 1992

Creator: Fateley, W. G. & Hammaker, R. M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Remote detection of trace effluents using Resonance Raman spectroscopy: Field results and evaluation

Resonance Raman spectroscopy (RRS) possesses many characteristics that are important for detecting, identifying and monitoring chemical effluents. Raman scattering is a coherent, inelastic, two-photon scattering process where an exciting photon of energy h{nu} promotes a molecule to a virtual level and the subsequently emitted photon is shifted in frequency in accordance with the rotational-vibrational structure of the irradiated species, thereby providing a unique fingerprint of the molecule. … more

Date: October 1, 1995

Creator: Sedlacek, A.J. & Chen, C.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Advanced organic analysis and analytical methods development: FY 1995 progress report. Waste Tank Organic Safety Program

This report describes the work performed during FY 1995 by Pacific Northwest Laboratory in developing and optimizing analysis techniques for identifying organics present in Hanford waste tanks. The main focus was to provide a means for rapidly obtaining the most useful information concerning the organics present in tank waste, with minimal sample handling and with minimal waste generation. One major focus has been to optimize analytical methods for organic speciation. Select methods, such as at… more

Date: September 1, 1995

Creator: Wahl, K.L.; Campbell, J.A. & Clauss, S.A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Effect of source gas chemistry on tribological performance of diamond-like carbon films.

In this study, we investigated the effects of various source gases (i. e., methane, ethane, ethylene, acetylene and methane + hydrogen) on friction and wear performance of diamond-like carbon (DLC) films. Specifically, we described the anomalous nature and fundamental friction and wear mechanisms of DLC films derived from gas discharge plasmas with very low to very high hydrogen content. The films were deposited on steel substrates by a plasma enhanced chemical vapor deposition process at room … more

Date: August 23, 1999

Creator: Erdemir, A.; Eryilmaz, O. L.; Fenske, G. R. & Nilufer, I. B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Field Raman spectrograph for environmental analysis

The enormous cost for chemical analysis at DOE facilities predicates that cost-saving measures be implemented. Many approaches, ranging from increasing laboratory sample throughput by reducing preparation time to the development of field instrumentation, are being explored to meet this need. Because of the presence of radioactive materials at many DOE sites, there is also a need for methods that are safer for site personnel and analysts. This project entails the development of a compact Raman s… more

Date: December 1, 1995

Creator: Haas, John W., III; Forney, Robert W.; Carrabba, Michael M. & Rauh, R. David

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Application of modern diagnostic methods to environmental improvement. Annual progress report, October 1994--September 1995

The Diagnostic Instrumentation and Analysis Laboratory (DIAL), an interdisciplinary research department in the College of Engineering at Mississippi State University (MSU), is under contract with the US Department of Energy (DOE) to develop and apply advanced diagnostic instrumentation and analysis techniques to aid in solving DOE`s nuclear waste problem. The program is a comprehensive effort which includes five focus areas: advanced diagnostic systems; development/application; torch operation … more

Date: December 1, 1995

Creator: Shepard, W.S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Surface-enhanced Raman fiberoptic sensors for remote monitoring

A new sensor design for remote surface-enhanced Raman scattering (SERS) measurements has been developed for environmental applications. The design features the modification of an optical fiber using layers of alumina microparticles and silver coatings for inducing the SERS effect at the sensing probe. A single fiber carries both the laser excitation and the SERS signal radiation, keeping optical parameters at the remote tip simple and consistent. The small tip size achievable with this configur… more

Date: September 1, 1995

Creator: Stokes, D.L.; Alarie, J.P. & Vo-Dinh, T.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Chemical and microstructural characterization of thermally grown alumina scales

An experimental program has been initiated to evaluate the chemical, microstructural, and mechanical integrity of thermally grown oxide scales to establish requirements for improved corrosion performance in terms of composition, structure, and properties. Iron aluminides of several compositions were selected for the study. Oxidation studies were conducted in air and oxygen environments at 1000{degrees}C. The results showed that the scaling kinetics followed a parabolic rate law but that the rat… more

Date: September 1995

Creator: Natesan, K.; Richier, C. & Veal, B. W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Operation and Performance of the Supercritical Fluids Reactor (SFR)

The Supercritical Fluids Reactor (SFR) at Sandia National Laboratories, CA has been developed to examine and solve engineering, process, and fundamental chemistry issues regarding the development of supercritical water oxidation (SCWO). This report details the experimental apparatus, procedures, analytical methods used in these experiments, and performance characteristics of the reactor. The apparatus consists of pressurization, feed, preheat, reactor, cool down, and separation subsystems with … more

Date: November 1, 1995

Creator: Hanush, R. G.; Rice, S. F.; Hunter, T. B. & Aiken, J. D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Studies of hydrogen-induced degradation processes in Pb(Zr {sub 1-x}Ti{sub x})O{sub 3} (PZT) and SrBi{sub 2}Ta{sub 2}O{sub 9} SBT ferroelectric film-based capacitors.

The integration of PZT and SBT film-based capacitors with Si integrated circuit technology requires the use of processing steps that may degrade the performance of individual device components. Hydrogen annealing to remove damage in the Si FET adversely affects both PZT and SBT, although the mechanisms of degradation are different. We have used Mass spectroscopy of recoiled ions (MSRI), X-ray diffraction (XRD), Raman spectroscopy and electrical characterization to study the mechanisms of hydrog… more

Date: June 25, 1999

Creator: Krauss, A. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department