The energy-momentum tensor in spontaneously broken non-Abelian gauge field theories is studied. The motivation is to show that recent results on the finiteness and gauge independence of S-matrix elements in gauge theories extends to observable amplitudes for transitions in a gravitational field. Path integral methods and dimensional regularization are used throughout. Green's functions Γμν(j)(q; p1,…,pj) involving the energy-momentum tensor and j particle fields are proved finite to all orders in perturbation theory to zero and first order in q, and finite to one loop order for general q. Amputated Green's functions of the energy momentum tensor are proved to be gauge independent on mass shell. 相似文献
Zusammenfassung Indicatoren für lang- und kurzzeitige Umweltbelastungen in verschiedenen geographischen Regionen mit ihren verschiedenartigen Belastungsgraden (z. B. Industrie, Landwirtschaft u. a.) sind weltweit mehr und mehr von Interesse. Die wichtigste Frage dabei ist, wie aussagefähig ein bestimmter Indicator für den Stand der Umweltbelastung betrachtet werden kann.Verschiedene Materialien wie Pflanzen, Tiere (Ganztiere bzw. Organe), Organe des Menschen (z. B. Placenta) und Böden wurden in den letzten Jahren als geeignete Indicatoren diskutiert. In verschiedenen Forschungsprogrammen unserer Arbeitsgruppe sind wir mit diesen Fragestellungen intensiv beschäftigt. Materialien wie menschliche Placenta, verschiedene Tierarten und deren Organe, Pflanzen und Böden wurden dabei untersucht, um geeignete Indicatormaterialien zu finden. An Hand einiger ausgewählter Beispiele soll die Aussagefähigkeit dieser Materialien diskutiert werden, wobei der Schwerpunkt auf die Unterscheidung zwischen normaler biologischer Streuung der Daten und dem Einfluß der Umwelt gelegt werden soll. Etwa 20 Elemente mit essentiellen Spurenelementen wie Cu, Fe, Mn, Zn usw. und toxischen Elementen wie Pb, Cd, Hg, As usw. wurden dabei untersucht.
Examinations on the suitability of different types of samples as indicators for heavy metal pollution
Summary Indicators for long- and short-term environmental pollution in different regions with different environmental influences (agriculture, industry, etc.) become world-wide more and more of interest. The main question in this connection is how a substance can give evidence for environmental research.Different materials like human placenta, animals (or some organs of these), plants and soils have been discussed in the last few years for use as indicator substances. The use of bioindicators will be discussed in this paper by means of some examples from the research work of our laboratory. About twenty elements, including nearly all the heavy metals like As, Hg, Cd, Pb, etc. and essential trace elements like Cu, Fe, Mn, Zn, etc. have been investigated in these experiments. Main emphasis is laid on the differentiation between normal biological scattering of data and the environmental influence.
Herrn Prof. Dr. W. Fresenius zum 70. Geburtstag gewidmet 相似文献
The thermal excitation of artificial brushite in dried air and normal atmosphere generates the following reactions: We could not register the monotropic γ→β and β→χ transformations by DTA. At low pH2O values unstable inordinate intermediates are formed until the exothermic transformation, at high pH2O value and in water a stable, secondary hydrogen phosphate of ordinate crystal lattice and γ-pyrophosphate originate. The amorphous intermediate compounds are pseudomorphous with the initial brushite. The lack of H2O hinders, whereas the excess of H2O promotes the formation of nuclei and crystallization of monetite and as a result of this its thermal existence region is expanded. Accordingly, during the dehydratation process in dry air the decrease of the 相似文献
We have investigated the insulating barrier of A1-oxidized A1Pb tunnel junctions. This study was effected by measuring the inelastic electron tunneling (IET) spectra of various junctions in which the insulator was formed by oxidizing the aluminum either in an O2 H2O or D2O plasma discharge at various temperatures between room temperature and 250°C. We found that those insulators formed at all temperatures in 02 and those formed at high temperatures (?150°C) in H2O and D2O are aluminum oxide with no evidence for any appreciable bulk hydroxide. The surfaces of these insulators do have adsorbed hydroxyl groups present, however. The insulators made at lower temperatures (<100°C) are also primarily aluminum oxide, but there is evidence for some bulk hydroxide. These “oxides” have a high concentration of surface hydroxy1 groups with indications of two types of surface hydroxyls. 相似文献
