Search results for "RADIOCHEMISTRY"

Trennung von Seltenen Erden aus der Atomkernspaltung an Kationenaustauschern

1967

Der Einflus einiger Versuchsbedingungen auf die Kationenaustauschtrennung der Seltenen Erden mit α-Hydroxyisobuttersaure wird untersucht.

Trennung des Insecticidgehaltes der Luft in den Aerosol-gebundenen und den gasf�rmigen Anteil

1974

Eine Differenzierung des staubgebundenen und des freien Anteils der Insecticide in der Luft ist moglich, wenn man die Aerosolfraktion mit Hilfe von Glasfaserfiltern abscheidet und die die Filter passierenden gasformigen Insecticide an Drahtnetze adsorbiert, die mit Polyathylenglykol 400 beschichtet sind.

Radiochemische Endpunktserkennung von Verteilungstitrationen

1969

Einfache Methoden zur Bestimmung des Aquivalenzpunktes von Verteilungstitrationen mit radioaktiven Indicatoren werden beschrieben. Dabei ist durch Ausnutzung des Geometrieeffektes von γ-Strahlern keine Abtrennung der Phasen erforderlich. Die Verwendung von β-Strahlern beruht auf der Loschung der Fluorescenz von flussigen Szintillatoren in der wasrigen Phase.

�ber Fehlerquellen bei der 14C-Bestimmung nach Verbrennung im Sauerstoff-Kolben

1971

Determination of gunshot residues by neutron activation analysis

1973

Systematic investigations of gunshot residues, deposited around the bullet hole, have been carried out. The traces were produced by firing on filter papers from distances of 5 to 200 cm using one rifle and three pistols as arms. Antimony, lead and barium were quantitatively determined after irradiating the samples in the nuclear reactor TRIGA Mainz by measurement of gamma-lines of122mSb,122Sb,207mPo and139Ba. The determinations were made purely instrumentally and-where the half lives were long enough-also after chemical separation of the nuclides. The amount of the elements were determined in dependence of the firing distance and of the area around the bullet hole.

Radiolanthanides in Nuclear Medicine

2004

Sorption of neptunium(V) on Opalinus Clay under aerobic/anaerobic conditions

2010

Abstract The interaction between neptunium(V) and a natural argillaceous rock (Opalinus Clay (OPA), Mont Terri, Switzerland) has been investigated in batch sorption experiments by varying pH (6–10), Np(V) concentration (10−12–10−4 M), solid-to-liquid ratio (2–20 g/L), and partial pressure of CO2 (10−3.5 and 10−2.3 atm) under aerobic/anaerobic conditions in saturated calcite solution. All batch experiments were carried out using well characterized aerobic and anaerobic dry powders of OPA. The results show a great influence of pH on Np(V) sorption. Under aerobic conditions sorption increases with increasing pH until maximum sorption is reached between pH 8–9. At pH>9 sorption decreases due…

Extending Limits of Chlorine Kinetic Isotope Effects

2012

Chlorine kinetic isotope effects exceeding semiclassical limits were observed in enzyme-catalyzed reactions, but their source has not been yet identified. Herein we show that unusually large chlorine kinetic isotope effects are associated with reactions in which chlorine is the central atom that is being passed between two heavy atoms. The origin of these large values is the ratio of imaginary frequencies for light-to-heavy species (the so-called temperature-independent factor).

A Method to Quantitatively Trap Volatilized Organoselenides for Stable Selenium Isotope Analysis

2011

If volatile organoselenides are to be analyzed for their stable Se isotope composition to elucidate sources and formation processes, organoselenides need to be trapped quantitatively to avoid artificial Se isotope fractionation. We developed an efficient trap of organoselenides to be used in microcosms designed to determine the Se isotope fractionation by microbial transformation of inorganic Se to volatile organoselenides. The recoveries of volatilized dimethyldiselenide (DMDSe) from aqueous standard solutions by activated charcoal and alkaline peroxide solution with subsequent freeze-drying and purification via a cation exchange resin were tested. Microcosm experiments with the Se-methyla…

Radioactively labelled epoxides. Part III. Tritium labelled steroid 16α, 17α-epoxides

1980

Tritium labelled (17-3H) 16α, 17α-epoxy-androst-4-en-3-one and 16α, 17α-epoxy-estra-1,3,5(10)-trien-3-ol have been prepared on a large scale (200-300 mg amounts) with efficient (i.e. activity of product exactly predictable) introduction of label. The preparative method is very inexpensive, since the tritium derives from tritiated water, the steroid starting materials are readily available, and high yields are obtained in all steps.