8,256 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Spectroscopy"  
prev Results: 25 - 48 next
open access

Effect of particle size on the carrier-distillation analysis of PuO$sub 2$

Description: A study was made to determine the effect of particle size on the carrier- distillation analysis of PuO/sub 2/ and to explain how to avoid the difficulties caused by large PuO/sub 2/ particles. The relative intensity of five elements was determined for three particle sizes and it was shown that it increases as the particle size becomes smaller. Further the line intensity of the added internal standard Co also increased with decreasing particle size. Accurate spectrochemical results were obtained… more
Date: January 1, 1974
Creator: Martell, C.J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Laser-based instrumentation for the detection of chemical agents

Description: Several laser-based techniques are being evaluated for the remote, point, and surface detection of chemical agents. Among the methods under investigation are optoacoustic spectroscopy, laser-induced breakdown spectroscopy (LIBS), and synchronous detection of laser-induced fluorescence (SDLIF). Optoacoustic detection has already been shown to be capable of extremely sensitive point detection. Its application to remote sensing of chemical agents is currently being evaluated. Atomic emission from … more
Date: January 1, 1982
Creator: Hartford Jr., A.; Sander, R. K.; Quigley, G. P.; Radziemski, L. J. & Cremers, D. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Ambient pressure photoelectron spectroscopy: a new tool for surface science and nanotechnology

Description: Progress in science often follows or parallels the development of new techniques. The optical microscope helped convert medicine and biology from a speculative activity in old times to today's sophisticated scientific disciplines. The telescope changed the study and interpretation of heavens from mythology to science. X-ray diffraction enabled the flourishing of solid state physics and materials science. The technique object of this review, Ambient Pressure Photoelectron Spectroscopy or APPES f… more
Date: March 12, 2008
Creator: Salmeron, Miquel; Salmeron, Miquel & Schlogl, Robert
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

UV and infrared absorption spectra and 248 nm photolysis of maleic anhydride (C₄H₂O₃)

Description: This article investigates maleic anhydride (C₂H₂(CO)₂O, Furan-2,5-dione) that is emitted into or formed in the atmosphere during bio-mass burning events as well as being a photochemical degradation product of some aromatic volatile organic compounds. The photochemical fate of maleic anhydride, however, is presently not well enough characterized to enable modeling of its impact on the environment and human health. In this study, the room temperature UV and infrared absorption spectra of maleic a… more
Date: July 2, 2019
Creator: Marshall, Paul; Papadimitriou, Vassileios C.; Papanastasiou, Dimitrios K.; Roberts, James M. & Burkholder, James B. (James Bart), 1954-
Item Type: Refine your search to only Article
Partner: UNT College of Science
open access

Ultrafast and nonlinear optical characterization of optical limiting processes in fullerenes

Description: The authors present recent results of broadband femotosecond (fs) transient absorption (TA) and broadband nanosecond (ns) optical limiting (OL) studies of C{sub 60} and derivatized C{sub 60}. Improvements in measurement techniques for fs TA spectra provide sensitivity to 10{sup {minus}5} in differential transmission, allowing detailed comparison of excited-state spectra with established energy level diagrams, as well as comparison of the ratio of triplet to singlet excited-state absorption cros… more
Date: October 1, 1997
Creator: Kohlman, R.; Klimov, V. & Shi, X.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Tank 11H Analytical Results as Input to DWPF Sludge Batch 4

Description: SRNL was requested by DWPF to conduct analyses on dissolved samples of Tank 11H material in preparation for DWPF processing. Two separate samples of Tank 11H were pulled during Tank Farm slurry and transfer operations. These samples have been designated Tank 11 - Sample 1 and Tank 11 - Sample 2. Aliquots of each slurry sample were digested in HNO3/HF and analyzed by inductively coupled plasma - atomic emission spectroscopy, inductively coupled plasma - mass spectrometry, and cold vapor - atomic… more
Date: September 1, 2004
Creator: CHRISTOPHER, BANNOCHIE
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Highlights of papers presented at the workshop on cold fusion phenomena

Description: This report contains highlights of formal oral papers presented at the Workshop on Cold Fusion Phenomena, hosted by Los Alamos National Laboratory and held May 23--25, 1989, in Santa Fe, New Mexico. General topics covered are: physics of fusion reactions; neutron and gamma-ray spectroscopy; colorimetry; and applicable condensed-matter physics, electrochemistry, and analytical chemistry.
Date: September 1, 1989
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Fourier transform ion cyclotron resonance precision atomic mass measurement limits

Description: The application of Fourier Transform Ion Cylcotron Resonance Mass Spectroscopy to precision atomic mass measurements is considered. Limits on the mass accuracy of this technique for atomic masses are discussed, and plans for future developments with application to fundamental weak interaction physics are presented.
Date: July 1, 1992
Creator: Kouzes, R.T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Laser induced fluorescence of trapped molecular ions

Description: Laser induced fluoresence (LIF) spectra (laser excitation spectra) are conceptually among the most simple spectra to obtain. One need only confine a gaseous sample in a suitable container, direct a laser along one axis of the container, and monitor the sample's fluorescence at a right angle to the laser beam. As the laser wavelength is changed, the changes in fluorescence intensity map the absorption spectrum of the sample. (More precisely, only absorption to states which have a significant rad… more
Date: October 1, 1980
Creator: Winn, J.S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

X-ray Emission Spectroscopy to Study Ligand Valence Orbitals in Mn Coordination Complexes

Description: We discuss a spectroscopic method to determine the character of chemical bonding and for the identification of metal ligands in coordination and bioinorganic chemistry. It is based on the analysis of satellite lines in X-ray emission spectra that arise from transitions between valence orbitals and the metal ion 1s level (valence-to-core XES). The spectra, in connection with calculations based on density functional theory (DFT), provide information that is complementary to other spectroscopic te… more
Date: March 2, 2009
Creator: Smolentsev, Grigory; Soldatov, Alexander V; Messinger, Johannes; Merz, Kathrin; Weyhermuller, Thomas; Bergmann, Uwe et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Raman spectroscopic and mass spectrometric investigations of the hydrogen isotopes and isotopically labelled methane

Description: Suitable analytical methods must be tested and developed for monitoring the individual process steps within the fuel cycle of a fusion reactor and for tritium accountability. The utility of laser-Raman spectroscopy accompanied by mass spectrometry with an Omegatron was investigated using the analysis of all hydrogen isotopes and isotopically labeled methanes as an example. The Omegatron is useful for analyzing all hydrogen isotopes mixed with the stable helium isotopes. The application of this … more
Date: February 24, 1997
Creator: Jewett, J.R., Fluor Daniel Hanford
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Fundamental studies of molecular multiphoton ionization

Description: For several years the authors have performed fundamental studies of molecular multiphoton ionization (MPI). We will present a potpourri of techniques and results chosen to illustrate the interesting complexities of molecular MPI. Techniques used include time-of-flight mass spectroscopy, photoelectron spectroscopy, supersonic expansion cooling of molecular beams, harmonic generation, two-color laser MPI, and polarization spectroscopy. Whenever possible the relevance of these results to resonance… more
Date: April 1, 1984
Creator: Miller, J. C. & Compton, R. N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Evaluation of an x-ray fluorimeter for measuring lead in paint

Description: A laboratory analysis of key performance features of the Warrington Microlead I XRF Analyzer was conducted. This analysis included the determination of instrument accuracy and precision as measured against standard reference materials as well as the instrument's ability to provide information for multiple layers of a lead-based paint.
Date: March 17, 1993
Creator: Klein, R.C.; Horn, F.T. & Wilson, R.D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

CHAPTER 7. BERYLLIUM ANALYSIS BY NON-PLASMA BASED METHODS

Description: The most common method of analysis for beryllium is inductively coupled plasma atomic emission spectrometry (ICP-AES). This method, along with inductively coupled plasma mass spectrometry (ICP-MS), is discussed in Chapter 6. However, other methods exist and have been used for different applications. These methods include spectroscopic, chromatographic, colorimetric, and electrochemical. This chapter provides an overview of beryllium analysis methods other than plasma spectrometry (inductively c… more
Date: April 20, 2009
Creator: Ekechukwu, A
Item Type: Refine your search to only Book
Partner: UNT Libraries Government Documents Department
open access

Detecting Molecular Properties by Various Laser-Based Techniques

Description: Four different laser-based techniques were applied to study physical and chemical characteristics of biomolecules and dye molecules. These techniques are liole burning spectroscopy, single molecule spectroscopy, time-resolved coherent anti-Stokes Raman spectroscopy and laser-induced fluorescence microscopy. Results from hole burning and single molecule spectroscopy suggested that two antenna states (C708 & C714) of photosystem I from cyanobacterium Synechocystis PCC 6803 are connected by effect… more
Date: August 3, 2007
Creator: Hsin, Tse-Ming
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

Multiscalar measurements of turbulence-chemistry interactions in nonpremixed flames

Description: 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: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Ultrasensitive molecular fluorescence spectroscopy in levitated microdroplets

Description: The extreme sensitivity of fluorescence spectrophotometry results from the fact that a molecule can undergo many excitation-emission cycles before destruction by photochemical degradation. For example, Rhodamine 6G (R6G) can emit in excess of 10{sup 5} photons before photolysis takes place. The fraction of emitted photons collected and converted to countable pulses can be as high as 10{sup {minus}3}, although 10{sup {minus}4} is more readily attainable. Therefore, sufficient signal exists for s… more
Date: January 1, 1990
Creator: Ramsey, J. M.; Whitten, W. B. (Oak Ridge National Lab., TN (USA)); Arnold, S. (Polytechnic Univ., Brooklyn, NY (USA)) & Bronk, B. V. (Chemical Research, Development and Engineering Center, Aberdeen Proving Ground, MD (USA))
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Analysis of TRU waste for RCRA-listed elements

Description: Analytical methods for RCRA listed elements on Portland cement type waste have been employed using both microwave and open hot plate digestions with subsequent analysis by inductively coupled plasma atomic emission spectroscopy (ICP-AES), inductively coupled plasma mass spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS), graphite furnace atomic absorption (GFAA) and cold vapor atomic absorption and fluorescence (CVAA/CVAFS). Four different digestion procedures were ev… more
Date: July 1, 1996
Creator: Mahan, C.; Gerth, D. & Yoshida, T.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
Back to Top of Screen