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- ItemNew electronic device for driving surface acoustic wave actuators(Amsterdam : Elsevier, 2009) Brünig, R.; Mensel, K.; Kunze, R.; Schmidt, H.Surface acoustic wave (SAW) actuators are driven by a high frequency signal. The frequency range for an ideal SAW-generation is usually very narrow banded and may shift depending on various environmental conditions. We present a new electronic device which self-aligns to the optimal excitation frequency within a wide range. Any kind of SAW-actuator can be used. The device continuously scans a certain frequency range and characterizes the SAW-component. The ideal excitation frequency is then determined and used to drive the SAW-device. In case of changes like loading conditions or temperature variations the device automatically readjusts to the optimal frequency and prevents possible damage of the device or actuator in case of an error. © 2009.
- ItemComplex loading and simulation of acoustic thickness shear mode resonator(Amsterdam : Elsevier, 2010) Brünig, R.; Weihnacht, M.; Guhr, G.; Schmidt, H.During the last decades thickness shear mode resonators (TSM, QCM) have been object of comprehensive research. Many approaches were made to describe the behavior and physical effects when loaded. We present a physical model that describes the TSM in the full frequency range, including overtones for a large variety of loadings (e.g. gases, liquids or solid materials). By using an automated curve fit algorithm, absolute values for the loaded material (e.g. thickness, viscosity) can be extracted. The model has been validated with a large number of experiments including liquids with complex viscosities, biomolecule interactions, electrochemisty or vacuum deposition techniques. Additionally, the appearance of layer resonances have been predicted and verified. Layer resonances are remarkable because they appear at even-numbered overtones, which have been considered to be impossible.