摘要:

An einigen Beispielen aus dem Isotopenlabor des Institutes für Biochemie der Pflanzen Halle werden Möglichkeiten und Arbeitsweisen bei der Synthese von Kohlenstoff-14- und Tritium-markierten Agrochemikalien und Zwischenprodukten sowie deren Anwendung bei der Untersuchung von Metabolismus und Verhalten in pflanzlichen Systemen und im Boden behandelt. Dabei wird z. T. auch Originalliteratur einbezogen sowie auf Übersichtsarbeiten auf diesem Gebiet hingewiesen.

ISSN:0021-1915    

DOI:10.1080/10256018908624141

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

In vorliegender Arbeit wird eine kurze Darstellung der Grundlagen, Erfordernisse, Vor- und Nachteile des Radioimmunoassay für Pflanzenhormone gegeben.

ISSN:0021-1915    

DOI:10.1080/10256018908624142

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The systemic organophosphate methamidophos was studied in conifers (spruce, pine, larch and dauglas-fir) with regard to the translocation, distribution and degradation. The32P-labelled insecticide was spread on the pretreated bark as an adhesive paste, and the following behaviour was investigated by counting and autoradiography during at most 48 d in trees up to 80 years of age. The localization of the insecticide in the phloem/xylem region of the trunk and the fixation of practical quantitative amounts of the insecticide and metabolites in the treated tree was the base for developing a new and effective method for control of the spruce bark beetle (Ips typographus L.) including the use of pheromone dispensers.

ISSN:0021-1915    

DOI:10.1080/10256018908624143

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Es wird eine neue apparative Variante zur quantitativen Bestimmung der14C-Verteilung in markierten Alkylaromaten durch Pyrolyse im Wasserstoffstrom beschrieben. Durch Verwendung von Quarz statt Edelstahl als Reaktormaterial konntein Nebenreaktionen, die systematische Fehler verursachen können, praktisch vollständig unterdrückt werden.

ISSN:0021-1915    

DOI:10.1080/10256018908624144

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The investigations of sediment movement with the use of radiotracers have been carried out in a surf zone of Lubiatowo. Inception of sand motion and sediment transport velocity were the objective of the experiment. The “spider” type construction was located at the depth of 0.7 m. An artificial sand made of iridium glass (γ = 2.660 kg/m3) containing 0.25 weight per cent of192Ir was used as a tracer. Fraction 0.15 … 0.20 mm have been chosen as the representative diameter of sand grains existing at the investigated bottom region. The inception of sand movement vs current velocity and wave conditions as well as displacement velocity of tracer mass were determined. The new improved construction, “spider II”, was designed and tested.

ISSN:0021-1915    

DOI:10.1080/10256018908624145

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The sorption of Eu-(152 + 154), Co-60 and Cs-134 from simulated fresh water solutions by different fresh water sediment fractions is investigated It is found that the sorption decreased by increasing the concentration of the hydrogen ion or the metal ion concentration. The results obtained are related to the composition, particle size and structure of the sediment fractions investigated, i.e. sand, coarse silt, fine silt and clay.

ISSN:0021-1915    

DOI:10.1080/10256018908624146

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Residence time distribution (RTD) studies were executed on a water – softening reactor consisting of three physically separated units in order to characterize its hydrodynamical behaviour. The measured RTD curves and the actual mean residence times were compared with the theoretical values set up by modelling the reactor as a hydrodynamical system. The experiments were carried out by means of radiotracer technique. Neither the mixing, nor the sedimentation reaches ideal flow. Flow type in the settling cylinder is far of that is expected.

ISSN:0021-1915    

DOI:10.1080/10256018908624147

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The leaching of solid inorganic waste from loaded concrete or cement by incoming water can be described in terms of a “steady-state” outward diffusion of the saturated solution, formed inside the pores. Expressions are derived for the amount of leached material as a function of the concentration of this saturated solution, the specific load, the porosity and the retardation by the tortuosity of the pores. As experiments on leaching start with a dry test specimen, a correction for the flow of the incoming water is necessary. The porosity and the retardation by the tortuosity of the pores, compared to diffusion in a dilute aqueous solution, can be determined by combining two radiotracer experiments: That on leaching of test specimens with measurements on diffusion through a thin plane sheet of loaded concrete or cement, using HTO as the radiotracer. Numerical evaluation of the derived equations permits a prediction of long-term leaching behaviour. Assuming a specific load of = 10% waste material and moderate solubilities, the “effective” diffusion coefficients in present concrete formulations are of the order of 10−17–10−15m2·s−1.

ISSN:0021-1915    

DOI:10.1080/10256018908624148

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Es wird eine weiterentwickeltes, isotopenanalytisches Verfahren zur probenchemischen Umsetzung von Kohlenwasserstoffen mit Chromium zu Wasserstoff bei 1300 K vorgestellt. Die erzielten Testergebnisse zeigen anhand der gemessenen δD-Werte, daβ Quarzöfen bei diesen Temperaturen noch keine die Isotopenmeβwerte beeinflussende Diffusion von Wasserstoff durch die Wandung zulassen. Auβerdem erfolgte die Reaktion nahezu spontan und vollständig, was die Methode zeitlich sehr effektiv macht.

ISSN:0021-1915    

DOI:10.1080/10256018908624149

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

In October 1987 we made preliminary studies of concentration of soil-CO2and its isotopic composition. The sample-size of soil air was about 100 cm3only, which is significantly reduced in comparison with other studies so far. The isotope analysis of such minute CO2samples were performed by a dynamic flow mass spectrometer. The air samples were taken from the depth of 10 … 75 cm at two points of a grass field, which were distanced a few meters apart. The measured δ13C values were very consistent for both points and they were ranging from –21.53 … –22.37‰ while the corresponding CO2concentration was ranging from 0.24 … 0.55%.

ISSN:0021-1915    

DOI:10.1080/10256018908624150

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor