Reinhard Lerch

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Many surface acoustic wave (SAW) devices consist of quasiperiodic structures that are designed by successive repetition of a base cell. The precise numerical simulation of such devices, including all physical effects, is currently beyond the capacity of high-end computation. Therefore, we have to restrict the numerical analysis to the periodic substructure.(More)
We propose an enhanced iterative scheme for the precise reconstruction of piezoelectric material parameters from electric impedance and mechanical displacement measurements. It is based on finite-element simulations of the full three-dimensional piezoelectric equations, combined with an inexact Newton or nonlinear Landweber iterative inversion scheme. We(More)
Dicarboxylic amino acids constitute the most numerous residues of insoluble elastin in which are potentially ionizable in the physiological range of pH. These residues are essential in facilitating productive electrostatic interaction between elastase and elastin. The present study has investigated the possibility that the glutamic and aspartic acid(More)
Many sensors and actuators in technical systems consist of quasiperiodic structures which are constructed by successive repetition of a base cell. Typical examples are piezoelectric composites used as ultrasonic transducers or surface acoustic wave (SAW) devices utilized in telecommunication systems. The precise numerical simulation of such devices(More)
A method for reconstructing the sound pressure profile from interferometer measurements using computed tomography is presented. In accordance with the term light diffraction tomography, in short we want to call the method light refractive tomography, because it is based on the sound pressure-induced refractive index change along the laser beam. We compare(More)
Today's most popular technology of ultrasonic flow measurement is based on the transit-time principle. In this paper, a numerical simulation technique applicable to the analysis of transit-time flowmeters is presented. A flowmeter represents a large simulation problem that also requires computation of acoustic fields in moving media. For this purpose, a(More)
This paper summarizes the results of a series of performance tests carried out as part of an evaluation of di erent graphics workstations. The graphics performance was determined by Viewperf 5.1. In addition, we present some results of a relatively simple graphics benchmark, which measures the raw performance with regard to Gouraud-shading. In order to get(More)
Among various techniques enabling absolute measurements of ultrasound pressure, light refractive tomography (LRT) is so far the only one which is noninvasive, omnidirectional, and provides time-resolved results in pascals. By exploiting all these advantages, LRT shows suitability for investigations of ultrasound pressure fields, even in the case of adjacent(More)