摘要:

It is well known that the condensed phase physical properties of molecular isotopic isomers are not the same. These differences in the vapor pressure, molar volume, surface tension, etc., are purely quantal phenomena. The effects are most exterme for isotopic substitution at hydrogen isotopes. Of the various physical properties which have been investigated the isotope effect on vapour pressure (VPIE) shows the largest ralative effects. In face, for hydrogen-deuterium substitution they range all the way from about inverse 2% per deuterium atom for nonpolar hydrocarbons (by inverse we mean that the molecule substituted with the heavier isotope has the higher vapor pressure) to as much as 20% normal (PH>PD) per deuterium atom for molecules which are strongle associated in the condensed phase. Such effects are about one order of magnitude larger than isotope effects which are observed in most systems on molar volumes, surface tension, etc. (Thus, for example, benxene at 20°C shows a rather small VPIE of 0.4% per atom D 3 but the molar volume effect is only 0.05% per D and the surface tension effect 0.03% [4].) This it would appear is the reason a majority of recent studies have been directed toward the VPIE. The emphasis in this paper reflects that trend and the balance of the discussion will deal almost exclusively with the vapor pressure isotope effect.

ISSN:0021-1915    

DOI:10.1080/10256016808551993

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

Es wird eine graphische Methode zur experimentellen Bestimmung des „over-all correction factor‟ kernphysikalischer Zählapparaturen, insbesondere mit Geiger-Müller-Zählrohren, beschrieben, Hauptvoraussetzungen für die Anwendung dieser Methode sind a) mehrere „ähnliche‟ Kernstrahlungsquellen, die sich ausschlieβlich in ihrer Aktivität jeweils um etwa den Faktor 5 unterscheiden, b) eine konstante und durch das Auswechseln der Strahlungsquellen unbeeinfluβte Versuchsanordnung, Die beschriebene Methode erweist sich besonders aus praktischen Gründen den bisher bekannten Methoden zur unmittebaren experimentellen Bestimmung des „over-all correction factor‟ g als überlegen (g = zw/z mit zw= wahre Zählrate, z = registrierte Zählrate).

ISSN:0021-1915    

DOI:10.1080/10256016808551994

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

Die vorliegende Arbeit berichtet über die elektrodialytische Herstelling von β-Meβquellen durch Sulfidfällung. Zur Markierung diente58Co. Es wurde die Abhängigkeit der Ausbeute von Zeit, Stromdichte, Säurekonzentration und Anolytvolumen untersucht Fremdkationen stören die Abscheidung.

ISSN:0021-1915    

DOI:10.1080/10256016808551995

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

It is presented the isotopic exchange of hydrogen in natural gas, crude oil, and underground water. The general behaviour of the isotopic exchange occuring in a system with a large number of components is given. A good agreement between the calculated and the experimental isotopic distribution factors is obtained in the case of the isotopic exchange of hydrogen between methane and underground water. The deuterium concentration of the crude oil samples inserts between the values obtained for methane and underground water. This fact is due to the presence of the isotopic exchange between these fluids.

ISSN:0021-1915    

DOI:10.1080/10256016808551996

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

ISSN:0021-1915    

DOI:10.1080/10256016808551997

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

ISSN:0021-1915    

DOI:10.1080/10256016808551998

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

ISSN:0021-1915    

DOI:10.1080/10256016808551999

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

ISSN:0021-1915    

DOI:10.1080/10256016808552000

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

ISSN:0021-1915    

DOI:10.1080/10256016808552001

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

ISSN:0021-1915    

DOI:10.1080/10256016808552003

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor