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High-Sensitivity Single-Molecule Fluorescence Detection in Theory and Practice

Description: The number of emitted photons that can be obtained from a fluorophore increases with the incident light intensity and the duration of illumination. However, saturation of the absorption transition and photodestruction place natural limits on the ultimate signal-to-noise ratio that can be obtained. Equations have been derived to describe the fluorescence-to-background-noise ratio in the presence of saturating light intensities and photodestruction. The fluorescence lifetime and the photodestruct… more
Date: 1989
Creator: Mathies, R. A.; Peck, K. & Stryer, L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Atomic and molecular science with synchrotron radiation

Description: This paper discusses the following topics: electron correlation in atoms; atomic innershell excitation and decay mechanisms; timing experiments; x-ray scattering; properties of ionized species; electronic properties of actinide atoms; total photon-interaction cross sections; and molecular physics. 66 refs. (LSP)
Date: November 7, 1989
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Luminescence from defects and impurity centers in yttrium oxide

Description: High-purity (99.999%) Y{sub 2}O{sub 3} powder is used as a starting material for fabricating high-temperature superconductors (HTS), and is frequently found as an unreacted second phase in the final product. We have found that as-received Y{sub 2}O{sub 3} contains Tb{sup 3+} paramagnetic impurity ions as determined by TSL and emission-spectra measurements. Deep luminescence traps (presumably Tb{sup 4+} ions) are formed in Y{sub 2}O{sub 3} when it is exposed to {gamma}-rays, x rays, or fluoresce… more
Date: January 1, 1989
Creator: Jahan, M.S.; Cooke, D.W.; Bennett, B.L.; Hults, W.L.; Maez, M.A.; Ott, K.C. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Conservation potential of compact fluorescent lamps in India and Brazil

Description: We evaluate the conservation potential of compact fluorescent lamps (CFLs) for managing the rapidly increasing electrical energy and peak demand in India and Brazil. Using very conservative assumptions, we find that the cost of conserved energy using 16 W CFLs is 4 and 6 times less than the long range marginal cost of electricity for the two countries. The cost of avoided peak installed capacity is 6 and 9.5 times less than the cost of new installed capacity for India and Brazil. The analysis i… more
Date: July 1, 1989
Creator: Gadgil, A.; Martino Jannuzzi, G. de (Lawrence Berkeley Lab., CA (USA) & Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Fluorescence dynamics and cross relaxation of 4+ curium in cerium tetrafluoride

Description: Fluorescence from Cm{sup 4+} has been observed for the first time. The dynamics of its emitting 5f state have been probed using time- and frequency-resolved laser-induced fluorescence. Nonexponential fluorescence decays were found from Cm{sub 0.001}Ce{sub 0.999}F{sub 4} and Cm{sub 0.05}Ce{sub 0.95}F{sub 4} at temperatures from 4.2 K to 300 K. A simple cross-relaxation model was found to fit the excited f-state dynamics of the Cm{sub 0.001}Ce{sub 0.999}F{sub 4} sample at low excitation intensity… more
Date: January 1, 1989
Creator: Liu, G.K. & Beitz, J.V.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Photoinitiated electron transfer in multichromophoric species: Synthetic tetrads and pentads

Description: This research project involves the design, synthesis and study of molecules which mimic many of the important aspects of photosynthetic electron and energy transfer. Specifically, the molecules are designed to mimic the following aspects of natural photosynthetic multistep electron transfer: electron donation from a tetrapyrrole excited singlet state, electron transfer between tetrapyrroles, electron transfer from tetrapyrroles to quinones, and electron transfer between quinones with different … more
Date: April 12, 1989
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Glancing angle x-ray studies of oxide films

Description: High brightness synchrotron radiation incident at glancing angles has been used to study inhibiting species present in low concentrations in oxide films on aluminum. Glancing incident angle fluorescence measurements give surface-sensitive information on the valence state of elements from the shape of the x-ray absorption edge. Angle-resolved measurements show the depth distribution of the species present. 15 refs., 4 figs.
Date: January 1, 1989
Creator: Davenport, A. J. & Isaacs, H. S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Energy transfer processes in solar energy conversion

Description: We have made substantial progress in experimental and theoretical studies in two areas: Photoinduced donor to acceptor electron transfer followed by back transfer in random solutions; and electronic excitation transport in systems with complex inhomogeneous spatial geometries and inhomogeneous energy distributions. Through the development of accurate statistical mechanical theories, we have been able to relate dynamics in complex systems to experimental observables. We have then used the experi… more
Date: November 1, 1989
Creator: Fayer, M.D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Ionic alkali halide XUV laser feasibility study

Description: The objective of this work is to assess the feasibility of a select set of ionic alkali halide XUV laser concepts by obtaining the relevant kinetic and spectroscopic parameters required for a proof-of-principle and conceptual design. The proposed lasers operate in the 80--200 nm spectral region and do not require input from outside radiation sources for their operation. Frequency up-conversion and frequency mixing techniques and therefore not considered in the work to be described. An experimen… more
Date: November 10, 1989
Creator: Yang, T. T.; Gylys, V. T.; Bower, R. D.; Harris, D. G.; Blauer, J. A.; Turner, C. E. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Time-resolved flourescence measurements of KrF emission produced by vacuum ultraviolet photolysis of KrF/sub 2/ mixtures

Description: Vacuum ultraviolet (VUV) light radiation was used to produce electronically excited KrF excimers (in D-, B- and C-states) by the photolysis of KrF/sub 2/ and F/sub 2//Kr mixtures at various excitation wavelengths. The excited KrF photoproduct quantum yield was measured over the excitation wavelength range of 120 to 200 nm, and a quantum efficiency of 0.45 was estimated at the peak absorption wavelength of 159 nm for KrF/sub 2/. The collision-free fluorescence lifetime of the B-X transition near… more
Date: January 1, 1989
Creator: Tiee, J.J.; Quick, C.R.; Hsu, A.H. & Hof, D.E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Mapping of upper electronic reaction surfaces by tuned laser photolysis and by absorption and emission spectroscopies

Description: Potential energy surfaces for photorotamerization of two intramolecularly hydrogen-bonded molecules, o-hydroxybenzaldehyde (OHBA) and methyl salicylate (MS), isolated in cryogenic matrices have been spectroscopically mapped. In addition, the external heavy atom effect of krypton and xenon matrices on the coupling between the S{sub 1} and T{sub 1} surfaces of 4-(dimethylamino)benzonitrile has been examined. Heavy atom matrices are known to increase rates of spin-forbidden processes. The phosphor… more
Date: July 1, 1989
Creator: Morgan, M.A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Laser spectroscopy at accelerator facilities

Description: The use of lasers in exciting fast atomic and molecular ions produced in accelerators is discussed. Collinear excitation of the ions is most efficient, and several examples of laser-induced fluorescence are given. These include tests of relativistic atomic structure, and atomic and molecular hyperfine measurements. Higher precision can be attained using rf double-resonance techniques in some cases. A variant of this technique, the raman double-resonance technique, is also introduced. The produc… more
Date: January 1, 1989
Creator: Berry, H.G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Development of intrinsic IPT scintillator

Description: We report on the development of a new polystyrene based plastic scintillator. Optical absorption, fluorescence and light output measurements are presented. Preliminary results of radiation damage effects are also given and compared to the effects on a commercial plastic scintillator, NE 110. 6 refs., 12 figs.
Date: July 31, 1989
Creator: Bross, A. D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Shelf edge exchange processes-II SEEP2-06, R/V Endeavor cruise 186

Description: The Shelf Edge Exchange Processes (SEEP) program sponsored by the United States Department of Energy is a multi-institutional effort designed to investigate the flux of suspended material from the continental shelf to the waters of the upper slope, and then possibly into the slope sediments. Phase I of SEEP consisted of a series of nine cruises and a mooring array across the outer continental shelf of New England during 1983--1984. Phase II focused specifically on the shelf/slope frontal region… more
Date: December 1, 1989
Creator: Wilson, C.; Behrens, W. J.; Flagg, C. N.; Wallace, D. W. R.; Wilke, R. J. & Wyman, K. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Shelf Edge Exchange Processes, II: SEEP2-08, R/V ENDEAVOR cruise 188

Description: The Shelf Edge Exchange Processes (SEEP) program sponsored by the United States Department of Energy is a multi-institutional effort designed to investigate the flux of suspended material from the continental shelf to the waters of the upper slope, and then possibly into the slope sediments. Phase I of SEEP consisted of a series of nine cruises and a mooring array across the outer continental shelf of New England during 1983--1984 (Behrens and Flagg, 1986). Phase II focused specifically on the … more
Date: December 1, 1989
Creator: Wilson, C.; Behrens, W. J.; Flagg, C. N.; Wallace, D. W. R.; Wilke, R. J. & Wyman, K. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

High-speed DNA sequencing: An approach based upon fluorescence detection of single molecules

Description: This document discusses the development of a laser based technique for the rapid sequencing of large fragments of DNA based upon the detection of single, fluorescently tagged nucleotides cleaved from a single DNA fragments. Demonstrated is significant progress on several of the important steps of this technique. The projected rate of sequencing is several hundred bases per second which is orders of magnitude faster than existing methods. Once developed, this technology could be utilized by inve… more
Date: January 1, 1989
Creator: Jett, J. H.; Keller, R. A.; Martin, J. C.; Marrone, B. L.; Moyzis, R. K.; Ratliff, R. L. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Evaluating thermographic phosphors in an operating turbine engine

Description: The results of a field test in a commercial turbine engine showed that we can remotely measure the temperature of engine components in operating engines using thermographic phosphors. The remote- measurement method exploits the temperature dependence of the characteristic decay time of the laser-induced fluorescence of thermographic phosphors. This paper summarizes recent work leading up to and including a successful test of the thermographic-phosphor method in an operating turbine engine. 6 re… more
Date: January 1, 1989
Creator: Noel, B. W.; Borella, H. M. (Los Alamos National Lab., NM (USA)); Lewis, W.; Turley, W. D. (EG and G Energy Measurements, Inc., Goleta, CA (USA)); Beshears, D. L.; Capps, G. J. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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