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Showing 1 to 20 of 53 for “"absorption cross-section"”.
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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 …
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IR laser photochemistry of alkanols and 3,3-dimethyloxetane
… enables calibration to be extended to lower absorption levels (about 200µJ for a signal-to-noise ratio of six) than is possible with the more usual transmission methods, and was found to be capable of measuring as little as 5µJ. A particular advantage of the technique, is that it is simple, …
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Imaging of volcanic trace gases by Fabry-Perot interferometer correlation spectroscopy
… HCHO. The sensitivity (weighted mean trace gas absorption cross section) of the one-pixel HCHO instrument is 2.28 × 10−20 cm2 molec−1. From the HCHO sensitivity, a BrO sensitivity of 6.21 × 10−18 cm2 molec−1 can be inferred due to the spectral similarity of the BrO and HCHO absorption cross …
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Photophysics of cadmium selenide quantum dot solids
… quantum dot electronic structure, the optical absorption ~ross-section, charge separation, and transport in cadmium selenide colloidal quantum dots. The electronic states and optical absorption cross-section are found to be less sensitive to changes in the dielectric environment than predicted …
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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 …
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Terahertz photomixing spectroscopy of two-dimensional semiconductor plasmons
… physical properties, for example scattering and absorption cross section, are relatively unknown. The primary purpose of this work is to develop a measurement system capable of revealing these properties and utilize this system to understand the absorption of radiation by two-dimensional …
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Optical Processes in Krypton and Krypton(2)fluoride: Absolute Cross-Sections for Multiphoton Ionization of Krypton (1S(0)), Photoionization of Metastable Atomic and Molecular States of Krypton, Andabsorption of Krypton(2)fluoride (4-Doublet-Gamma)
A microwave absorption apparatus has been used to measure a cross section for the three-photon, resonantly-enhanced ionization of Kr(('1)S(,0)) at 193 nm. The presence of a two-photon resonance with the Kr 6p 3/2 (,2) level enabled the generation of large electron densities and a measurement of the …
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Critical assessment of thorium reactor technology
… itself offers a significantly greater neutron absorption cross-section than uranium at thermal energies, resulting in greater efficiency and smaller geometries. Certain thorium-based fuels can also significantly reduce proliferation by denaturing the thorium fuel cycle product U-233 (which is …
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Theoretical study of electronic absorption spectra and photodissociation dynamics of atmospherically relevant molecules
The absorption of solar radiation by atmospheric species and the corresponding photoinduced processes, define the chemistry of a planet's atmosphere. While many of these photoinduced processes and their effects are well- known, even in Earth's atmosphere there are gaps in our understanding. The …
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Experimental determination of the buckling for unusual geometrical shapes using paraffin
… constant Σ<sub>a</sub> = the macroscopic absorption cross section v = the neutron velocity D = diffusion coefficient C = diffusion cooling coefficient The resulting values of the diffusion parameters are: Σ<sub>a</sub> v = 4858 ± 162 sec⁻¹ D = 25911 ± 202 sec⁻¹ cm² C = 1186 ± 2558 sec⁻¹ …
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Remote Sensing of the Lower Atmosphere: From Surface Concentration to Mixing Layer Height
Differential Optical Absorption Spectroscopy (DOAS) is a remote sensing technique to detect different trace gas concentrations in the atmosphere. The Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements by the Pandora instrument scan the sky at different elevation angles …
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Synthesis, Linear and Nonlinear Photophysical Characterization of Two Symmetrical Pyrene-terminated Squaraine Derivatives in Solution
… to improving their optical properties. The absorption and emission properties of these derivatives were determined in order to gain an insight into the intensity of this type of interaction, their aggregation behavior and compare them with results obtained through quantum chemical …
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Neutronic evaluation of GCFR core diluents and reflectors
… reactivity. While low values of the macroscopic absorption cross section, [Sigma]a, and slowing down power, [xi] [Sigma]s, are qualitatively useful predictors of good performance, it was found that only full scope calculations were valid for quantitative assessment. For example, several materials …
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Development of a Chlorine Dioxide Gas Concentration Monitoring Unit and Kinetic Analysis of the Effect of Chlorine Dioxide Treatment on Color and Microbial Content Change of Spinach
… arise due to the variability of the molecular absorption cross section which must be known to determine the concentration present. Depending on the wavelength being used and the temperature of the medium, the molecular absorption cross section changes. The purpose of this study was to develop …
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Application of sensitive spectroscopic techniques to intramolecular dynamics and combustion kinetics
… apparatus and software for acetylene absolute absorption cross section measurements is also discussed. The observation and assignment of high-resolution spectra of the A' A" - X1 A' transition of HCBr and DCBr, recorded using Frequency Modulation Spectroscopy, is described in the second …
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Adaptive Fiber Source for Label-free Nonlinear Microscopy
… several cellular functions. Due to the low absorption cross-section of the two-photon and three-photon excitation processes, especially for the endogenous fluorophores, high peak power broadband laser sources are important in improving nonlinear microscopy generation efficiency. Multimode …
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FASPEC, a program to determine group constants for up to 47 groups in a fast neutron spectrum
… Input is facilitated by prompting in each case. Cross section look-up tables were provided by the Very Improved Monte Carlo code (VIM) for a mid-range Infinite hexagonal lattice. Self-shielding effects are included indirectly. A brief user's guide is provided. Group constants calculated and …
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Physical and radiative properties of coated nanoparticle aggregates
… electrical mobility, surface area, and optical cross-sections. When applied to atmospheric BC aging, the model provides new insights into the climate impact of these short-lived climate forcers. The absorption enhancement of non-uniformly lightly-coated BC is less pronounced than that of …
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Ultrafast Dynamics of Individual Air-Suspended Single-Walled Carbon Nanotube
… linear polarization along the tube axis for the absorption and emission of light, excitonic nature in SWCNT excitation). However, there are still several controversial parameters of SWCNTs (e.g. quantum efficiency, absorption cross section, radiative lifetime, and Auger recombination lifetime). …
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Measurement and analysis of the resolved resonance cross sections of the natural hafnium isotopes
… a ductile metallic element with a large neutron absorption cross section. It can be used in reactor control rods to regulate the fission process. The NEA High Priority Request List for nuclear data presents a need for improved characterisation of the hafnium cross section in the resolved …
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