Abstract: A piezoelectric resonator element of crystallographic point group 32, which can be operated as a thickness shear resonator contacting a carrier medium includes a singly rorated Y-cut (S1,S2) that is essentially rotated through an angle ?about the crystallographic x-axis, which differs from crystal cuts that are temperature-compensated in air or vacuum, wherein the cut has a negative temperatue coeffcient of the resonace frequency f(T) in a predetermined temperature range, preferably between 10° C. and 40° C., when there is no contact with the carrier medium, while the value of the linear temperature coeffcient a of resonance frequency in the same temperature range is less than 1 ppm/° C., preferably less than 0.5 ppm/° C. when the resonator is inb contact with the carrier medium. The resonator element (1) can additionally be provided with at least one layer sensitive to the parameter to be measured.

Abstract: A piezoelectric resonator element of crystallographic point group 32, which can be operated as a thickness shear resonator contacting a carrier medium includes a singly rorated Y-cut (S1,S2) that is essentially rotated through an angle &PHgr; about the crystallographic x-axis, which differs from crystal cuts that are temperature-compensated in air or vacuum, wherein the cut has a negative temperature coefficient of the resonance frequency f(T) in a predetermined temperature range, preferably between 10° C. and 40° C., when there is no contact with the carrier medium, while the value of the linear temperature coefficient a of the resonance frequency in the same temperature range is less than 1 ppm/° C., preferably less than 0.5 ppm/° C. when the resonator is in contact with the carrier medium. The resonator element (1) can additionally be provided with at least one layer sensitive to the parameter to be measured.

Abstract: To obtain large, high-quality crystals of a metal orthophosphate, in particular GaPO4 or AlPO4, from a nutrient solution with the use of seeds, a seed crystal is used having at least two rod- or wafer-shaped legs which form an angle with each other and define a main growth region, and which are positioned eccentrically in the single crystal grown. Contagious faces of two seed legs, which have been chosen for crystal growing, enclose an angle <180°. In this way the yield of the high-quality crystal region will be increased.

Abstract: To obtain large, high-quality crystals of a metal ortho-phosphate, in particular GaPO4 or AlPO4, from a nutrient solution with the use of seeds, the proposal is put forward that a seed crystal with at least two rod- or wafer-shaped legs be used, which seed legs form an angle with each other and define a main growth region, and which are positioned eccentrically in the single crystal grown. Contiguous faces of two seed legs, which have been chosen for crystal growing, enclose an angle <180°. In this way the yield of the high-quality crystal region will be increased.

Abstract: An AC generator may be connected to the signal leads of a piezoelectric transducer in order to induce mechanical vibrations in the transducer via the inverse piezoelectric effect. For determination of the vibration characteristics of the transducer provisions are made for a subtraction unit, whose one input is fed with the excitation signal of the AC generator while the other input is connected to the signal leads of the transducer. An evaluation unit is connected to the output of the subtraction unit; it displays and processes the measurement signal derived as the difference of the response signal of the transducer and a signal proportional to the excitation signal.

Abstract: In addition to having at least one piezoelectric sensor element, a transducer is provided with at least one further measuring element, which is influenced by the state variable to be measured in the same way as the piezoelectric sensor element, and has its own signal lead.The additional measuring element may also be a piezoelectric element which may be excited so as to produce mechanical vibrations by utilizing the inverse piezo-effect, the change of the vibration characteristics of the vibration system consisting of the excited piezo-element and its environment serving as a measurement value for a static or quasi-static measurement.

Abstract: A transducer with a flexible sensor element for measurement of mechanical values, at least one flexible piezoelectric sensor element being provided for piezoelectrical or capacitive measurement, the opposite surfaces of the sensor element being at least partially connected to electrically leading contact surfaces.

Abstract: A transducer device for measuring mechanical values on hollow bodies, such as the internal pressure in pipes, by detecting deformation in the outer surface thereof, comprises a housing for removably enclosing the hollow body whose outer surface deformation is to be measured and at least one elastic sensor element which is capable of being elastically and at least indirectly pressed against the outer surface of the hollow body by an elastic endorsing element and capable of stretching due to the deformation of the hollow body due to frictional contact therewith. The endorsing element is combined with the sensor element and/or at least a part of the housing into one piece, whereby manufacture and adjustment of the transducer device are simplified.

Abstract: A transducer comprising a piezoelectric measuring sensor element for measurement of mechanical values on hollow bodies, especially of the pressure distribution within pipes, the piezoelectric sensor element being a flexible piezoelectric film, the opposite surfaces of the film being in connection with electrically leading contact surfaces, and the measuring sensor element being at least partially and at least indirectly closely joinable to the surface of the hollow body.

Abstract: A transducer for mechanical measured variables, especially a pressure transducer, having a heat pipe system within the housing, the heat pipe system is connected on one side to the thermally high stressed parts of the transducer, and on the other side to parts not exposed to heat or cold. The sensor element of the transducer is cooled through heat transport by means of an alternatively vaporizing and condensating working fluid within the heat pipe system.