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Journal of Radioanalytical and Nuclear Chemistry
Authors: J. Leonhardt, H. Bothe, E. Langrock, E. Maul, P. Morgenstern, D. Müller, and H. Thümmel

Abstract  

The elemental concentration of C, Ca, Fe, Sr, Si, S were determined for 5 borehole brown coal samples by means of NAA, PAA and X-ray techniques. The correlation function between carbon content and the heat values and also between Si, Fe, Ca and Sr contents and ash content are discussed.

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Summary  

Lithium-ion batteries are widely used as a power source for portable electronic devices. Currently, only 50-70% of the theoretical capacity of the layered oxide cathode (positive electrode) materials could be reversibly used. The reason for this limitation is not fully understood in the literature. Recent structural and chemical characterizations of chemically delithiated (charged) cathodes suggest that loss of oxygen from the lattice may play a role in this regard. However, during the chemical delithiation process any proton inserted from the solvent could adversely affect the oxygen content analysis data. The challenge in addressing this issue is to detect and determine precisely the proton content in the chemically delithiated samples. The prompt gamma-ray activation analysis (PGAA) facility at the Nuclear Engineering Teaching Laboratory (NETL) is used to determine the proton content in the layered oxide cathode LiNi0.5Mn0.5O2 before and after chemical delithiation. The data are compared with those obtained with Fourier transform infrared (FTIR) spectroscopy, which can provide mainly qualitative analysis. The technique has proved to be promising for these compounds and will be applied to characterize several other chemically delithiated Li1-xCo1-yMyO2 (M = Cr, Mn, Fe, Ni, Cu, Mg, and Al) cathodes.

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Abstract  

In the boron neutron capture therapy, an accurate determination of the boron content in a biological sample is very important. The boron content was investigated with a standard solution of boron which was administered intraperitoneally with a dose of 750 mg/kg body weight into mice induced cancer cells and tumors. The boron content for two types of a sample was compared to the boronophenylalanine for the tumor and the ethylamine derivatives for the induced cancer cell, which were also investigated for their accumulation rate in each organ such as blood, spleen, liver, kidney and brain. An analytical quality control was carried out by using certified reference materials such as Peach Leaves, Apple Leaves and Spinach Leaves. The relative error of the measured values was in good agreement within 2% to the certified values.

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Abstract  

The effects of neutron scattering by hydrogen within targets for cold neutron prompt -ray activation analysis (CNPGAA) have been characterized. For most targets studied, the probability for neutron absorption, and hence CNPGAA sensitivities (counts·s–1·mg–1), decrease with increasing H content and with target thickness. Comparisons with results from thermal neutron PGAA indicate that the effects of cold neutron scattering differ from those of thermal neutron scattering. CNPGAA sensitivities for l/v nuclides show similar sensitivity decreases, while Sm sensitivities show smaller decreases.

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Abstract  

The photonuclear reactions used for this isotopic analysis are as follows:16O(γ, n)15O threshold energy 15.7 MeV;18O(γ, p)17N threshold energy 16.3 MeV.15O is a pure β+ emitter of half-life 2.03 minutes, whereas17N presents a 4.2 second neutron emission. The principle of the method is founded on the simultaneous measurement of the above characteristic radioactivities, the intensities of which are proportional to the respective quantities of16O and18O present in the irradiated sample. The potentialities of this new oxygen isotope analysis method, based on the use of an electron accelerator, are described. Detection limit of 0.1 μg18O is easily attainable. The equipment designed and built to industrialise this technique is described. It allows a hundred samples to be analysed automatically, the accelerator, detection instruments and pneumatic transfer circuits being controlled by a logic system linked to an electronic chronometer.

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Abstract  

It has been demonstrated that pixel-by pixel processing of series of autoradiography images for revealing the dynamics of decay of the induced radionuclides is an efficient approach for mapping of radionuclides in the sample in activation autoradiography. Concepts of virtual scanner and corresponding software for linearization of dependence of optical density on scanner response (luminosity) have been introduced. The concept provides unification of the subsequent processing of autoradiograms, irrespective of the method as to how the digital image has been obtained. Algorithms and the software for estimation of decay parameters of a radionuclide mixture for each pixel using a series of coaxially positioned images have been developed. The software is able generate a set of the derivative meta-images allowing a conclusion to be made about the presence of the inclusions in question. To increase the reliability of radionuclide mapping it is suggested to use analysis of distribution of half-life values estimated for pixels of image zone(s) pointed by a special mask.

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