Authors:K. Nomura, K. Tokumistu, T. Hayakawa, and Z. Homonnay
Perovskite oxides of composition (Sr1-xCax)(Fe0.5Co0.5)O3- were investigated for CO2 absorption properties and were proved to be useful as materials for CO2 absorption in the temperature range from 550 to 850 °C. The absorption rate of CO2 increased with Ca doping. The mechanical treatment of perovskite oxides for several minutes, especially for the oxides containing a small amount of Ca, was found to be effective for activating the oxides for CO2 absorption and for reducing the starting temperature of CO2 absorption by about 80 °C. However, it was not less effective to treat the oxides for a long time. The site distortion due to Sr and Ca ions at site A and the mixed valence states at site B were confirmed to be effective for CO2 absorption at high temperatures. During the absorption of CO2, a spinel compound was formed according to the following reaction: 2(Sr,Ca)(Fe,Co)O2.5 + CO2
(Sr,Ca)CO3 + (Sr,Ca)(Fe,Co)2O4.
HF absorption enhancements following major geomagnetic storms are analysed, using the superposed epoch method, to examine the geomagnetic latitude limit of the after-effect phenomenon. The absorption data were obtained from one double hop and two single hop A3 transmission paths with ionospheric points at Fgeomag = 3:54oN and ~6. 40oN (15. 40 MHz), Fgeomag ~ 9N (4. 87 MHz), and Fgeomag ~ 11oN (6. 09 MHz) respectively. Presently, the results have shown that enhancement in absorption following major storms could be traced to the low latitude of 3. 54oN.
Absorption spectroscopic properties for various Pu oxidation states in nitric and hydrochloric acid solutions were investigated
with UV-Visible spectrophotometry. As a result, it was confirmed that the intensities of the major absorption peaks had a
tendency to decrease for Pu(III), Pu(IV) and Pu(VI) in HCl and HNO3 media, and the major peak positions were shifted to longer or shorter wavelengths depending on the complexforming abilities
of Pu(III), Pu(IV) and Pu(VI) with the chloride or nitrate ion with increasing acid concentrations. The values of the wavelength
and the molar absorptivity for the principal peaks of Pu(III), Pu(IV) and Pu(VI) in NHO3 and HCl solutions were similar to those reported in other works. The values of the molar absorptivity for the principal peaks
of Pu(III), Pu(IV) and Pu(VI) in the HNO3 solution were a little higher than those in the HCl solution.
γ-Ray absorption spectroscopy has been used to accurately determine the Si and Ge content in SiGe alloys. This technique provides
a fast, accurate, and non-destructive method for determining concentrations of components in binary systems.
Authors:N. Saleh, K. Al-Saleh, and A. Abu El-Haija
The quantitative interpretation of X-ray fluorescence /XRF/ data is often difficult because of matrix effects. The intensity of fluorescence measurement for a given element is not only dependent on the concentration of the element, but also on the mass absorption coefficients of the sample for both excitation and fluorescent radiation. In this paper, a new approach for the determination of absorption and transmission correction factors is described.
Authors:Joaquín Azagra-Caro, Ignacio Fernández-de-Lucio, François Perruchas, and Pauline Mattsson
Most studies of patents citations focus on national or international contexts, especially contexts of high absorptive capacity,
and employ examiner citations. We argue that results can vary if we take the region as the context of analysis, especially
if it is a region with low absorptive capacity, and if we study applicant citations and examiner-inserted citations separately.
Using a sample from the Valencian Community (Spain), we conclude that (i) the use of examiner-inserted citations as a proxy
for applicant citations, (ii) the interpretation of non-patent references as indicators of science-industry links, and (iii)
the traditional results for geographical localization are not generalizable to all regions with low absorptive capacity.
Authors:L. Elegant, P. Maria, and N. Ziari-Chalmani
Absorption heats of hydrogen sulphide in aqueous solutions of monoethanolamine, diethanolamine and triethanolamine were determined by calorimetry. The measured enthalpies were compared to those calculated on the basis of solubility measurement and to the enthalpies of protonation of hydrogen chloride at 25‡.
Self-absorption correction of low-energy (<100 keV) -radiation is a much debated subject when applying low-energy -rays for dating purposes. Some investigations have hitherto focused on the possibility of using either irradiating of the sample and subsequent absortiometry or introducing physical correction. In the present paper an automatic procedure was elaborated using the occurrences of other low-energy -lines in the sample, those of234Th. Theoretical considerations are described on the basis of the mass absorption coefficients as a function of energy and atomic number. These considerations are verified by experiments with rock forming oxides and carbonates mixed with Standard Reference Material. Finally, an example is given for the application of the self-absorption correction approach.
Authors:G. Baptista, E. Montenegro, C. Barros Leite, and A. Paschoa
The accuracy of the quantitative analysis of thick targets by XRF is impaired by effects due to the absorption of X-rays in
the matrix associated with the non-uniformity of the X-ray beam and the lack of knowledge of the actual distribution of trace
elements in the target. The uncertainty in the elemental mass associated to a definite number X-rays detected is discussed
in the paper. A correction factor is derived to account specifically for the effect of the absorption of X-rays and the non-uniformity
of the X-ray beam.
The etching and annealing behaviour of heavy ion nuclear tracks have been studied in glass detectors namely sodalime, phosphate and quartz using optical absorption spectroscopy. All these glass detectors were exposed at 90° and 45° for different ions, with collimated beams of varying energies. The absorption difference spectrum was employed to describe the annealing kinetics. A mathematical relation proposed in our laboratory was used to explain the annealing behaviour of radiation damage due to heavy ion beams in glass detectors. The activation energy was obtained from a new formulation and is found to be 0.16 eV in sodalime, 0.56 eV for phosphate and 0.69 eV for quartz glass detectors.