Arsen, Antimon, Zinn,

Ohne Zusammenfassung     

Untersuchung von Milch

Ohne Zusammenfassung     

Highly resolved transmission infrared microscopy in polymer science

Over the last few years, the use of synchrotron-based IR sources for high-resolution microspectroscopy has been a subject of great interest. The special characteristics of synchrotron radiation allow one to obtain high quality IR spectra at high spatial resolution using commercial grade IR microscopes situated at IR beamlines. The application of this technique to the study of polymeric materials is discussed, with examples from a series of heterogeneous polymeric materials, which include polymer blends and fibre-reinforced polymer composites, from studies undertaken at the MIRAGE Beamline, LURE, Paris, France.     

Imaging biological specimens with the confocal scanning laser microscope/macroscope

A new confocal scanning laser microscope/macroscope (cslm/M) has recently been developed. It combines in one instrument the high resolution capability of a confocal scanning beam microscope for imaging small specimens, with good resolution confocal imaging of macroscopic specimens. Some of its main features include: (a) 0.25 μm lateral resolution in the microscope mode and 5 μm lateral resolution in the macroscope mode; (b) a field of view that can vary from 25 μm × 25 μm to 75,000 μm × 75,000 μm; (c) capability for acquiring large data sets from 512 × 512 pixels to 2048 × 2048 pixels; (d) 0.5 μm depth resolution in the microscope mode and 200 μm depth resolution in the macroscope mode.

In this work the cslm/M was used to image whole biological specimens (> 5 m diameter), including insects which are ideal specimens for the macroscope. Specimens require no preparation, unlike scanning electron microscope (SEM) specimens which require a conductive coating. The specimens described in this paper are too large to be imaged in their entirety by a scanning beam laser microscope, however they can be imaged by slower scanning stage microscopes. In the macroscope mode the cslm/M was used to acquire a large number (e.g. 20–40) of confocal image slices which were then used to reconstruct a three-dimensional image of the specimen. High resolution images were collected by the cslm/M by switching to the microscope mode where high numerical aperture (NA) objectives were used to image a small area of interest. Reflected-light and fluorescence images of plant and insect specimens are presented which demonstrate the morphological details obtained in various imaging modes. A process for three-dimensional visualization of the data is described and images are shown.     

Problems with spontaneous breakdown in reggeon field theories

We prove a theorem which states that if a reggeon field theory undergoes spontaneous breakdown as a result of the pomeron intercept being above one, then the shifted Lagrangian must in general develop terms which are non-canonical from the point of view of reggeon Lagrangians. We discuss the interpretation of these terms and point out some of the problems associated with them.