ISSN:0021-1915    

DOI:10.1080/10256019008622415

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The purpose of this paper is to discuss briefly the basis, technique and efficiency of luminescence dating. Thermoluminescence and optically-stimulated luminescence are useful for dating of quaternary sediments.Contents: Sediment Dating, Thermoluminescence Dating, Thermoluminescence (TL), Dating Method, Sources of Error, Dosimetry, Dating Techniques, Optical Dating (OSL), Sediments, References.

ISSN:0021-1915    

DOI:10.1080/10256019008622416

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The general thermodynamics in high pressure sorption processes and the isotopic shifts of the gases H2, N2, CH4und CO2were investigated by adsorption and desorption experiments on charcoal at pressures up to 25 MPa. The calculations of thermodynamic relations in the mentioned systems were carried out on the basis of a new three parameter equation for high pressure adsorption isotherms as well as a modified RAYLEIGH equation, in particular for the isotopic experiments.

ISSN:0021-1915    

DOI:10.1080/10256019008622417

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

A method is proposed for reiterated measurements by turns of13C and15N NMR signals at intact rat liver tissue. Eight minutes after Wistar rats had been injected 1,2-13C;15Nglycine, the liver was excised and stored in the triple resonance probe-head of a 2.1 Tesla NMR spectrometer. Alternatively13C and15N spectra were taken over some hours. Continued enzymatic activities of the liver tissue were seen in terms of metabolic changes of each of the carbon and nitrogen groups of glycine. Different half lives were found for the disappearance of the groups. The measurements gave insights into the kinetics and metabolism of an amino acid as an example to follow the vitality of an isolated organ non-destructively.

ISSN:0021-1915    

DOI:10.1080/10256019008622418

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

By means of different concentrations the signal-to-noise ratios of Tc-99-NMR spectra were determined applying well measurable Tc-samples [tetrabutylammoniwn pertechnetate, TBA (TcO4)J and a 250 MHz-spectrometer. The signal-to-noise ratios of the spectrawere determined by using the integrated routines of the firm's software and accumulating different number of scans. By fittings of data of the signal-to-noise ratio dependence and by extrapolation the minimum Tc-concentralion could be empirically found out. Applying a duration of measurements of 12 hours about 10−7molar concentrations can be determined.

ISSN:0021-1915    

DOI:10.1080/10256019008622419

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The developed Sol-Gel Hydrolysis Process was applied to produce uranium oxide microspheres suitable for use as nuclear fuel. Different preparation conditions of washing, feed solution aging and microsphere soaking were tried to produce dense UO3- and UO2-micospheres. The effect of reduction time and temperature on the density and porosity of the microspheres was carried out to optimize the preparation parameters. The total surface area, total pore volume and pore radius of UO3- and UO2-microspheres were measured through N2gas adsorption and application of the BET-equation at 77 K. The effect of the preparation conditions on crystallite size of the samples was made through ray diffraction analysis. Examination of the prepared uranium oxides by differential thermal analysis and thermal gravimetric analysis was carried out.

ISSN:0021-1915    

DOI:10.1080/10256019008622420

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Thoriumdioxide was selected as a second promoter for nickel catalyst in addition to chromium oxide which was proved to be suitable to accelerate the H/D isotopic exchange reaction between hydrogen and water vapour. A series of Ni/Cr2O3/ThO2catalysts were prepared by the co-precipitation technique. The amount of Ni was 70 … 90 mol%, while that of Cr2O3was 0 … 20 mol% and that of ThO2ranges from 0 … 30 mol%. This type of catalysts is sensitive for water condensation on its surface. The total surface area, total pore volume and pore radius of the catalysts were calculated from nitrogen adsorption on their surfaces at 77 K and application of the BET-equation.

ISSN:0021-1915    

DOI:10.1080/10256019008622421

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Successful choice of the suitable catalyst composition for hydrogen/deuterium exchange reaction between hydrogen and water requires understanding of chemical kinetics as well as surface properties and activity in both liquid- and vapour phases. The present study deals with the thermodynamic and kinetic behaviour of a simple liquid phase reaction on the surface of nickel catalyst promoted with zirconium oxide used for the H/D exchange. This study helps understand the condensation of water on the catalyst surface during operation which leads to its poisoning. In this specific case water molecules are responsible for selective poisoning of this type of catalysts. The reaction rate constant, the increase in Gibb,s free energy, the enthalpy, the entropy of activation and the energy of activation were calculated.

ISSN:0021-1915    

DOI:10.1080/10256019008622422

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

It was investigated the phytotoxicity as well as the fate of dinobuton and dinobutonmethyl in bean and cucumber plants and in apple fruits. Dinobutonmethyl is more phytotoxic than dinobuton. Generally dinobuton and dinobutonmethyl behave similarly after application on the apple surface and also after treatment of the leaves of bean and cucumber plants. After 3–5 days only about 50% of the applied radioactivity were found on the surface of the systems. Probably dinobuton and dinobutonmethyl as well as dinoseb as hydrolysis product are able to leave the plant systems unchanged.

ISSN:0021-1915    

DOI:10.1080/10256019008622423

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

A system with 3 new types of radiation meters for intensity measurement, spectrometry, activity measurement and dosimetry is described. The application of microcomputer technique as well as the utilization of data prozessing via personal computers confer to the user extensive rationalization effects in the accomplishment and evaluation of these measurements.

ISSN:0021-1915    

DOI:10.1080/10256019008622424

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor