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Abstract  

The detectors used primarily for the measurement of X-rays and gamma-rays are discussed because of their predominance in analytical measurements, and having the most dramatic improvements.

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Abstract  

Mössbauer spectroscopic studies were carried out on some synthesized iron complexes of Schiff's bases. The studies have evidenced that iron/II/ and iron/III/ species were formed, and no stereoisomers were found. However, the complex of bis/acetylacetone diethylene triamine/ had shown the geometric isomers, and only the Fe/III/ species formed. Immersion of the chelate of iron bis/salicylaldehyde ethylene diamine/ in aerated distilled water for a day had resulted in the conversion of the entire iron/II/ species into the iron/III/ complexes. The exposure to atmosphere had converted a part of iron/II/ into iron/III/ and resulted in distortion of the iron/II/ chelates. This leaves a room to think that oxygen transport or absorption may bring change in the oxidation number of the central metal ion or distortion in the structural arrangements.

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Abstract  

Thermally Stimulated Current (TSC) spectrometry has been applied to the characterization of polymeric materials. The study of a series of amorphous polymers having different physical structures has shown that the compensation parameters are independent of physical aging; contrarily, the activation enthalpy distribution reflects the evolution of the heterogeneity of the amorphous phase. In copolymers, TSC allows us to identify segregated amorphous phases. In semi-crystalline polymers, with semi-rigid chains, we have shown the existence of an amorphous crystalline interphase characterized by a plateau in the temperature distribution of activation enthalpy.

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Abstract  

Mössbauer effect was used for the characterization of the radioactive waste treatment products, e.g. precipitate formed during the treatment of LLAW (Low Level Active Waste) using iron compounds and their conditioned matrix obtained by cementation.

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Abstract  

The Mössbauer parameters were determined on a series of catalyst mixtures of iron and zinc oxides with variable quantities of zinc. From these results, a change in the crystal structure of the iron oxide when introducing zinc into the samples was observed. The corundum structure of the -Fe2O3 phase was transformed into the spinel type of zinc ferrite when zinc oxide was present in any quantity. By means of these parameters a strong electronic interaction between the zinc ferrite and the zinc oxide present in excess was evident. The catalysts were analyzed using X-ray fluorescence /XRF/ and X-ray diffraction /XRD/.

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Abstract  

Pulser and live timer are alternate tools. Dead time effects can be expressed in terms of a pulse rate dependent factor of the counting yield. The task of their correction should be shifted from the live timer of the ADC to a central timing unit. A new method is proposed, combining the advantages of the pulser and the live timer, where by each selected and accepted event is adjoined to a clock time interval and each selected but not accepted event to a dead time interval. The length of each interval is determined by the arrival of the next selected event.

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Abstract  

Countries around the world are deploying radiation portal monitor systems to interdict the illicit shipment of radioactive material crossing international borders. Because of their high efficiency for gamma-ray detection, most deployed systems are based on plastic scintillators and are non-spectroscopic in capability. Spectroscopic portal monitor systems are undergoing engineering development for near term deployment. The ability to identify the detected radionuclides may allow improved operational handling of radiation alarms, particularly those from the normal commerce of naturally occurring radioactive material. The goal for improved systems is to increase the sensitivity to threats while reducing the operational impact of nuisance alarms.

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