Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 29 for “"absorption cross sections"”.
-
Heavy-Ion Interaction Models for Radiation Transport
… with finding the values for the nuclear cross sections used in the Boltzmann equation for space radiation transport and dose estimates. An extraordinary number of cross sections are required because of the large number of ion types and their extensive energy range, The Lippmann-Schwinger …
-
Studies of resonance in ²³Na, ²⁶Mg, ⁴¹K, ⁵⁵Mn and ⁵⁹Co
… normalized to the resonance integral and thermal cross section of gold. Little work of this character has been done previously for these nuclides so that comparative results are not generally available. However, those values that were in the literature, did agree reasonably well with the results …
-
Elastic photon scattering below neutron emission threshold in Bi, 208Pb, 207Pb, 206Pb, Tl, Hg, Ce, and Ba
Average elastic photon scattering cross sections were measured for Bi 208Pb 207Pb, 206Pb, Tl, Hg, Ce, and Ba at excitations between 4.5 MeV and the respective neutron emission thresholds. The incident photon energy resolution ranged from 50 to 150 keV. Ground state transition widths were determined …
-
Variance Spectroscopy and its Application to the Study of Single-Wall Carbon Nanotubes
… new method was developed combining variance and absorption analysis to determine absolute E11 absorption cross sections for eleven different (n,m) species. The measured absorption cross sections were found to increase nonlinearly with decreasing diameter. A set of measured and estimated …
-
Detectability of biosignature gases in the atmospheres of terrestrial exoplanets
… from the HIgh-resolution TRANsmission molecular absorption (HITRAN) database: oxygen, ozone, methane, nitrous oxide, methyl bromide, methyl chloride, hydrogen sulfide, carbonyl sulfide, phosphine, and sulfur dioxide. The deep investigation of the HITRAN biosignature gases in this study is …
-
Novel Cladding Designs for Engineering Electromagnetic Scattering
… matrix to manipulate the scattering and absorption cross sections. Utilizing Lorenz-Mie scattering theorem, we thoroughly examine tensor-form surface impedance and the corresponding scattering properties, aiming to find the optimal cloaking strategy under different application scenarios .
-
A lattice boltzmann/s n framework for coupled heat transfer and neutron transport problems
… conductivity and temperature-dependent neutron cross sections. The neutron transport equation is solved using the discrete ordinates method (SN ); and the heat conduction equation is solved using the lattice Boltzmann method (LBM). In the SN method, the angle in the integro-differential form of …
-
Numerical modeling study of a neutron depth profiling (NDP) system for the Missouri S&T reactor
… a handful of light elements with large neutron absorption cross sections. This work discusses the possibility of coupling Particle Induced X-ray Emission spectroscopy with Neutron Depth Profiling to yield additional information about the depth profiles of other elements within a material. The …
-
Photophysical characterization of toluene and 3 pentanone for quantitative imaging of fuel/air ratio and temperature in combustion systems
… pressure and bath gas composition. In this work, absorption cross-sections, fluorescence quantum yields and oxygen quenching efficiencies of toluene-LIF were investigated in a heated flow cell (300 - 900 K) and absolute fluorescence quantum yields of 3-pentanone in dependence on excitation …
-
Capture cross sections in the KeV region
Many workers have attempted to determine neutron absorption cross sections and average resonance parameters with varying degrees of success. Values of the latter parameters for a given isotope often vary as much as a factor of two or three from one worker to another. This dissertation is an attempt …
-
Experimental Interrogation Of One-Dimensional Excitons In Cadmium Selenide And Cadmium Telluride Quantum Nanostructures
… band-gap energies, polarized emission, and large absorption cross sections make them quite attractive for potential use in photovoltaic and optoelectronic devices. The quantum-confined radial dimension of quantum wires increases the coulombic interaction between photo-generated excitons, and …
-
Evaluation of fast neutron shielding effectiveness in light-element compounds
… ability to reduce neutron energy and their high absorption cross sections, lightweight and low atomic number (Z) materials that contain neutron absorbers are the de facto choice for shielding against fast neutrons. Thus, an optimized concentration of neutron absorbers relative to the hydrogen …
-
A System For Conducting Laser-Induced Fluorescence Measurements On Gas Mixtures Exposed To Alpha Radiation
… the resulting chemical products. Because strong absorption cross sections for nitric oxide are too deep in the ultraviolet to effectively use the cavity ringdown method, laser-induced fluorescence spectroscopy was seen as a viable alternative. Using a certified mix of NO<sub>2 </sub>and a second …
-
Mass-independent sulfur isotope fractionation during photochemistry of sulfur dioxide
… of a variety of experimental conditions. Two absorption regions of SO2 are tested - photolysis in the 190 to 220 nm region and photoexcitation in the 250 to 350 nm region. Experimental conditions modified include temperature, SO2 pressure, bath gas pressure, and addition of reactive gases (C2 …
-
Novel resonant and light-guiding phenomena in photonics
… very accurately models the scattering and absorption cross sections, as long as the resonant scatterer has spherical/cylindrical symmetry, or is sufficiently smaller than the resonant wavelength of the incident wave. We apply it to study the scattering of light from spherically symmetrical …
-
Addition and recombination reactions of unsaturated radicals using a novel laser kinetics spectrometer
… flash photolysis kinetics experiments via direct absorption. The spectral range of the laser, when used with a harmonic generator, covers most of the visible wavelength region, allowing for the detection of a wide array of organic radical species. Paired with a temperature-and pressure-controlled …
-
Wide range analysis of ozone gas concentration in ultraviolet region
… the development of optical gas sensor employing absorption spectroscopy technique for ozone concentration measurement. Additionally, wide range analysis has been conducted to improve range of ozone concentration measurement using ultraviolet light absorption. Simulation of ozone absorption cross …
-
Three-photon Absorption Process In Organic Dyes Enhanced By Surface Plasmon Resonance
Multi-photon absorption processes have received significant attention from the scientific community during the last decade, mainly because of their potential applications in optical limiting, data storage and biomedical fields. Perhaps, one of the most investigated processes studied so far has been …
-
Spectroscopy and Photo-induced Chemistry of Atmospherically Significant Criegee Intermediates and Hydroxyl Radicals
… of the ion signals near the peak of broad absorption profiles, indicating rapid excited state dynamics. The UV depletion spectra and corresponding absorption cross sections were evaluated, and utilized with the solar actinic flux to estimate the atmospheric lifetimes of Criegee …
Page 1 of 2