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Summary  

A method has been developed for analyzing pyrite quantitatively in the sediments of Erhai Lake in southwest China using 57Fe Mössbauer spectroscopy combined with a series of acidic pre-treatments. Following a washing with an alkaline solution (0.1N NaOH), the sediment samples were successively treated using HCl, HF, and then HCl (65 °C). The residues thus prepared were analyzed for pyrite using 57Fe Mössbauer spectrometry. The presence of pyrite was also confirmed in the acidic residues of the sediments using sulfur K-edge X-ray absorption near edge structure. This method can be used to measure pyrite in aquatic sediments, especially when the concentration of pyrite is very low and the particles of pyrite are small or the crystallinity is low, and even in amorphous status. In addition, vertical variations of pyrite contents are positively correlated with organic matter and negatively correlated with hematite, superfine paramagnetic ferric iron and sedimentation rate in the cored sediment from the Erhai Lake. All these geochemical indicators may also reflect environmental changes in sedimentation conditions and diagenesis.

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New palladium(II) complexes with pyrazole ligands

Part II. Synthesis, spectral and thermal studies, and antitumor evaluation

Journal of Thermal Analysis and Calorimetry
Authors: Carolina V. Barra, Fillipe V. Rocha, Adelino V. G. Netto, Regina C. G. Frem, Antonio E. Mauro, Iracilda Z. Carlos, Sandra R. Ananias, and Marcela B. Quilles

Abstract

This study describes the synthesis, IR, 1H, and 13C{1H} NMR spectroscopic as well the thermal characterization of the new palladium(II) pyrazolyl complexes [PdCl2(HmPz)2] 1, [PdBr2(HmPz)2] 2, [PdI2(HmPz)2] 3, [Pd(SCN)2(HmPz)2] 4 {HmPz = 4-methylpyrazole}. The residues of the thermal decomposition were identified as Pd0 by X-ray powder diffraction. From the initial decomposition temperatures, the thermal stability of the complexes can be ordered in the sequence: 1 > 2 > 43. The cytotoxic activities of the complexes and the ligand were investigated against two murine cancer cell lines: mammary adenocarcinoma (LM3) and lung adenocarcinoma (LP07) and compared to cisplatin under the same experimental conditions.

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Abstract  

A peculiar interference phenomenon is discussed, which consists of memointerference (or vibrointerference) of waves generated by a set of sources of incoherent but monochromatic (e.g. Mössbauer) radiation and arriving at the surface of an oscillating resonant detector simultaneously, with the accuracy of the resonance width, i.e. within the duration of the detector phase memory. Possible applications of this phenomenon are discussed.

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Abstract  

A new terminology of Mössbauer pattern analysis is introduced. In this approach Mössbauer parameters are considered as functions of a number of externally adjusted physical parameters at which the spectrum has been recorded. Our approach can also help to systematize Mössbauer data for the identification of individual physical or chemical species from the corresponding patterns present in the spectrum.

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Abstract  

151Eu and 141Pr Mössbauer spectroscopy was applied to study the effects of Pr substitution for Eu or Ba atoms in Eu1-xPrxBa2Cu3O7- and EuBa2-xPrxCu3O7-, respectively. It was found that there exists a correlation between the 151Eu isomer shift and the onset temperature of the superconducting transition, independent of the location of Pr. This shows that the extra electrons provided by the Pr increase the electronic density in the copper oxide planes and in the 4f orbitals of Eu31, simultaneously. The polycrystalline compound EuBa1.3Pr0.7Cu3O7- has been investigated by 141Pr Mössbauer spectroscopy. The observed 141Pr isomer shift, (4.2 K) = 0.10(15) mm/s relative to PrF3, reflects a valence state of 3+ for the Pr located at the Ba site in EuBa1.3Pr0.7Cu3O7-, being in contrast to the valence state of 3.4+ found earlier for Pr which was situated at the rare earth site. This means that the valence state of Pr substituted for Eu is different from that of Pr substituted for Ba. These results suggest that the suppression of superconductivity by Pr substituted for the rare earth atoms is a consequence of the hole filling effect.

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The main goal of this work was to apply thin-layer chromatography (TLC) in the investigation of different binding media (proteins, sugars, waxes, resins, and oils) found on samples of two mummifed bodies of saints originating from 1200 AD and 1500 AD. The historical samples were compared by testing them for the presence of different inorganic and organic compounds. The chemical methods used were TLC, microscopy, X-ray fuorescence spectrometry, and Fourier transformed infrared spectroscopy. The detected similarities in the composition of the binding media coatings on two mummies indicated that those were not applied immediately after death but much later showing resemblance in their preservation treatments. Moreover, according to the composition of the materials detected, the coatings did not seem to have had considerable impact on the mummifcation of the bodies. The combination of TLC and other chemical methods proved to be an effective and low-cost tool for obtaining valuable information during the archeological investigations.

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Abstract

Four polydentate azomehines and their mono- and binuclear Pt(II), Cu(II), and Ni(II) complexes were synthesized and characterized. The resulting complexes were characterized by FTIR, magnetic measurements, elemental analysis, conductivity measurements, and thermal analysis. Electronic spectra and magnetic susceptibility measurements sustain the proposed distorted square-planar structures for the copper complexes. The electronic spectra display the characteristic pattern of square-planar stereochemistry for the other complexes. The thermal analyses have evidenced the thermal intervals of stability and also the thermodynamic effects that accompany them. Azomethine complexes have a similar thermal behavior for the selected metal ions. The decomposition processes as water elimination, chloride anion removal as well as degradation of the organic ligands were observed.

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Abstract  

The ASEDRA (Advanced Synthetically Enhanced Detector Resolution Algorithm, patent pending) has been successfully applied as a post processing algorithm to both sodium iodide (NaI(Tl)) and cesium iodide (CsI(Na)) scintillator detectors to synthetically enhance their realized spectral data resolution by as much as a factor of three, wherein from these detectors the “raw” unprocessed spectra are traditionally of poor resolution. ASEDRA uses noise reduction and built-in high resolution Monte Carlo radiation transport based detector response functions (DRFs) to rapidly post-process a spectrum in a few seconds on a standard laptop; gamma lines are extracted with an accuracy that makes the scintillator detectors competitive with higher resolution, higher material cost detectors. ASEDRA differs from other tools in the field, such as Sandia’s GADRAS software, in that ASEDRA performs a differential spectrum attribution and cumulative extraction from the sample spectrum, rather than an integral-based approach, as in GADRAS. Previous publications have highlighted the successful application of ASEDRA in samples with plutonium and various isotopes. A new SmartID nuclide identification package to accompany ASEDRA has recently been implemented for test and evaluation purposes for sample attribution; in addition, the application of ASEDRA+SmartID has occurred with success in long dwell cargo monitoring and SNM detection applications, enabling new protocols for HEU detection. Overall, this paper presents recent developments and results along with a discussion of follow-on steps in the development of ASEDRA as an effective field gamma spectrum analysis tool for low cost scintillators.

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, Koutirev , M 1998 J Catal 174 : 231 – 241 10.1006/jcat.1998.1983 . 15. Delgass WN , Haller GL , Kellerman R , Lundsford JH (eds) ( 1979 ) Spectroscopy in

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