Reinhard Lerch

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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 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)
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)
Todays data sets arising from computational mathematics are extremely large which poses increasing demands for performance (in the sense of graphics-performance) on interactive visu-alization systems. " Real-time " interaction interfaces have proven useful for the analysis of these data sets, but real-time performance has been difficult to achieve with such(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)
A two layer ultrasonic stack transmitter made of a ferroelectret material with a diameter of 1.5 cm was developed for emitting a chirp signal with a sound pressure level of more than 90 dB at a distance of 1 m for an artificial bat head. Compared to a single layer transmitter, the resonance frequency of a two layer stack actuator is shifted down to 100 kHz.(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)