G. E. A. Meier

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This paper describes the implementation of a novel technique called Background Oriented Schlieren that can produce quantitative visualization of density in a flow. This technique uses only a digital still camera, a structured background, and inverse tomographic algorithms which can extract two-dimensional slices from a three-dimensional flow. This has been(More)
Tomographic methods are used for the investigation of three-dimensional compressible flow fields by means of interferometric methods. A modified algebraic reconstruction technique algorithm is applied. The algorithm proved to give reliable reconstructions from experimentally measured projection data in the case of an unrestricted angular view. The method(More)
Eiger is the next-generation single-photon-counting pixel detector following the widely used Pilatus detector. Its smaller pixel size of 75 µm × 75 µm, higher frame rate of up to 22 kHz, and practically zero dead-time (~4 µs) between exposures will further various measurement methods at synchrotron sources. In this article Eiger's suitability for X-ray(More)
In the present paper the dependences of the resistivity p and the Hall voltage U H of polycrystalline Ni-Cu and Ta-Cu multi-layered thin films on the layer thickness d r are discussed. The thickness dependence of p and U, can be well understood using a simple model in which the layers are considered as parallel resistors, whereby the resistivity of a single(More)
We explore the concentration dependence of the zero shear viscosity of well-defined dendritically branched polystyrene solutions in relation to their internal structure. Whereas in the past the change of total molecular weight was achieved via change of the number of generations (G) for fixed backbone segment length (average number of units between(More)
In this communication we suggest, using the droplet picture in phase transitions, that polymer chains are localized before the phase separation in polymer mixtures. The effect is expected to be significant when the correlation length is of the order of the size of the polymer chain, 1-eusually for conventional polymers well above the phase separation.(More)
The synthesis and characterization of model cyclic diblock copolymers of styrene (St) or perdeuterated styrene (St-d8) and butadiene (Bd) are presented. Since conventional methods of characterization cannot separate completely the cyclic copolymer from its linear precursor, differences in the micellar behavior were used as a method for investigation of(More)