Michael Lehmann

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The purpose of this research is the quantitative investigation of decorrelation-induced phase errors in speckle interferometry. Measurements in speckle interferometry are inherently affected by decorrelation, i.e., by alterations of the speckle fields during measurement. Likewise, the random phases carrying the interferometric information change during(More)
Investigations over the years have shown that the mirror-finished Al2O3 ceramic is a much more suitable frictional counterpart to ultrahigh molecular weight (UHMW) polyethylene than metal. Despite the extremely gread hardness difference between polyethylene and Al2O3 ceramic, a considerable lower wear rate is obtained for the polyethylene socked with this(More)
Long-range holographic experiments have been performed over distances as large as 12 km. Holograms and images of retroreflector and Scotchlite objects were obtained. The reference wave was supplied by a retroreflector placed next to the object, and the source of illumination was a Q-switched ruby laser. Resolutions obtained varied with atmospheric seeing(More)
Transition metal oxides exhibit an amazing spectrum of properties and applications. ZnO is an excellent example as it possesses interesting piezoelectric and electromechanical coupling properties, and it has been used in UV light-emitting diodes, lasers, photovoltaic solar cells, UV-photodetectors, varistors, and even heterogeneous catalysis. For the(More)
The sensitivity, reliability, reproducibility and ease of use of the WILCO LFC package integrity test method was evaluated by preparing and testing a series of rubber-stoppered glass vials which were modified by affixing a glass micropipette through the vial side wall. The test units contained water, 50% aqueous ethanol, 20% lithium chloride or 20% aqueous(More)
Recent climate warming has led to asynchronous species migrations, with major consequences for ecosystems worldwide. In woody communities, localized microclimates have the potential to create feedback mechanisms that can alter the rate of species range shifts attributed to macroclimate drivers alone. Mangrove encroachment into saltmarsh in many areas is(More)
Interest in bleached photographic gratins and holograms arose as early as 1965.” Several theoretical investigations of photographically generated gratings showed that greatly improved efficiencies could be obtained by elimination of the absorption and reflection inherent in a silver imngc.a*Y This information stimu lated interest in improving diffraction(More)
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