Round and group quadratic forms over global fields

An anisotropic quadratic form φ is called round if φ ?aφ whenever φ represents a nontrivially. All round forms over global fields are completely determined. A generalization of a round form, called a group form, is investigated over global fields.     

Influence of solvent on the superparamagnetic relaxation of nanocrystalline Fe3O4 in ferrofluids

Mössbauer spectra for 5 nm Fe₃O₄ nanocrystallites coated with different surfactants were measured and show a significant influence on superparamagnetic relaxation with and without the solvent in ferrofluids.     

Mössbauer spectroscopy in china

Mössbauer spectroscopy in China is in a period of rapid development. In this review the recent developments and achievements in Mössbauer spectroscopy by Chinese scientists are discussed. Particular emphasis is placed on the application of the method to archaeology.     

The green stain on the bark of plane trees — A new probe for studying the iron content in air pollution

The origin of iron complexes detected several years ago in the green stain on the bark of plane trees was not clear up to now. Using Mössbauer spectroscopy, we were able to show that these iron complexes result from air pollution deposits. Since all iron compounds detected in air pollution so far are also present in green stain on the bark of plane trees in high concentrations, it seems to be a very effective indicator of air pollution.     

On the classification of unimodular quadratic forms

We introduce two arithmetical invariants and show how they may be used to classify certain unimodular quadratic forms over Hasse domains. A cancellation result is given as an application.     

A Mössbauer investigation of SnO2 films with preferred orientation of crystallites

The textured SnO₂ films with different thickness in the range of 600–11200Å prepared by chemical vapour deposition (CVD) have been characterized by using conversion electron Mössbauer spectroscopy (CEMS) couping with X-ray diffraction (XRD) and Auger electron spectroscopy (AES). The evidence for the existence of an interaction between SnO₂ and glass substrate with the formation of a interface layer about 200Å thick has been discussed. SnO₂ existing in polycrystalline state with preferred crystal face orientation is found as long as the SnO₂ films are thick than 1800Å.