Abstract: The invention relates to an ultrasonic resonator cell, comprising: a cell body having first and second opposite end faces forming at least one sample cavity extending between the end faces for receiving a sample to be investigated, a first electro-acoustical transducer wafer, a second electro-acoustical transducer wafer, a first end piece, a second end piece, and at least one fastener for applying axial pressure on the first and second end pieces for fastening the first and second electro-acoustical transducer wafers to the cell body on the respective end face of the cell body.

Abstract: A method for determining acoustic parameters of a liquid (1) in a resonator arrangement having a resonator chamber (2) includes the following steps: acoustic excitation of the liquid in the resonator chamber (2) in such a way that a sequence of liquid resonances is excited in a frequency range in which the wall material of the resonator chamber (2) and/or associated transducers (6) have natural resonances with amplitude different from zero, and measurement of the associated resonance frequencies of the liquid in the resonator chamber (2); determining an observed deviation of the measured resonance frequencies from ideal resonance frequencies in an ideal resonator corresponding to the resonator chamber (2); calculating a simulation function (yk), which is a function of the acoustic parameters of the liquid (1) and represents calculated deviations of the resonance frequencies from the ideal resonance frequencies; adapting the calculated deviations to the observed deviations through variation of the acoustic par

Abstract: The invention relates to a cell for measuring acoustical properties of a fluid sample comprising cell body having first and second opposite substantially flat end faces and forming at least one sample cavity for receiving a sample to be investigated and first and second electro-acoustical transducer wafers each having first and second main surfaces, said first main surface of said first and second transducers being positioned at said first and second end surfaces respectively, of said cell body. The invention proposes to provide at least one sealing means at one end face.

Abstract: A method of determining a phase separation concentration of a sample substance in a solution, comprises the steps of measuring values of a physical quantity of the solution containing the sample substance with at least one sample substance concentration lower then the phase separation concentration, wherein the physical quantity characterizes an interaction of the solution with sound waves, determining a concentration function representing a dependency of the physical quantity on the sample substance concentration lower then the phase separation concentration, and determining the phase separation concentration as a concentration value at which the concentration function equals a predetermined critical value of the physical quantity of the solution containing the sample substance in a saturated condition. Furthermore, a concentration determining device is described.

Abstract: The invention provides a method for determining optimal concentrations of additives which are capable to protect sensitive biomacromolecules, e.g. proteins or nucleic acids, against denaturation and aggregation in a solution comprising at least one species of a biomacromolecule and at least one species of a protective additive comprising: a) treating said solution with ultrasonic waves; and b) recording the value of one or more ultrasonic parameters, such as the ultrasonic velocity in said solution and/or the ultrasonic absorption of said solution. The above method allows to detect critical changes of the ultrasonic parameter dependent from the concentration of the protective additive and indicative of interactions or changes of interactions between additive and biomacromolecules and/or between different biomacromolecules and/or changes of the conformation of the biomacromolecules.

Abstract: A sample container (10) for ultrasonic measurements is described, having a container part (20), which forms a sample receptacle, the container part (20) having a wall material (21) whose composition and/or thickness is selected in such a way that ultrasound waves may be coupled with maximum transmission from the outside through the wall material (21) to the inside into the sample container (10). Methods for ultrasonic measurement of a sample in a sample container of this type, methods for manufacturing the sample container, and a construction comprising the sample container and a resonator chamber are described.

Abstract: A method for determining acoustic parameters of a liquid (1) in a resonator arrangement having a resonator chamber (2) includes the following steps: acoustic excitation of the liquid in the resonator chamber (2) in such a way that a sequence of liquid resonances is excited in a frequency range in which the wall material of the resonator chamber (2) and/or associated transducers (6) have natural resonances with amplitude different from zero, and measurement of the associated resonance frequencies of the liquid in the resonator chamber (2); determining an observed deviation of the measured resonance frequencies from ideal resonance frequencies in an ideal resonator corresponding to the resonator chamber (2); calculating a simulation function (yk), which is a function of the acoustic parameters of the liquid (1) and represents calculated deviations of the resonance frequencies from the ideal resonance frequencies; adapting the calculated deviations to the observed deviations through variation of the acoustic par

Abstract: Methods of diagnostic investigation of a sample from a biological organism are described, which comprise the steps of determining at least one physical quantity of said sample, wherein said at least one physical quantity characterizes an interaction of said sample with sound waves, and correlating said at least one physical quantity with reference data, which characterize at least one condition of said sample or said organism, for obtaining at least one diagnostic characteristic. Furthermore, diagnostic devices are investigating biological samples with such methods are described.

Abstract: In a piston pressure device with a sealing device (10) for sealing between spaces of different pressure that includes an elastomer (12) as a first component and a material plastically deformable under pressure as a second component, whereby the components ensure sealing at various pressure differences, a piston (30) and a piston shaft (20), the piston (30) is axially shiftable in relation to the piston shaft (20) and the sealing device (10) is arranged form-closed in a recess between the piston (30) and the piston shaft (20).

Abstract: A high-pressure apparatus with driving device (10) and pressure generating device (30) has a frame configuration (20) through which the driving device and the pressure generating device are connected but detachable (FIG. 1A).

Abstract: A pump system for producing high and exactly controllable pressure levels includes a piston pump which has a piston (32) connecting to a spindle shaft (22), a spindle nut (44) on said spindle shaft, a cylinder block (34) having a bore (36) for receiving said piston, a mechanism (14, 16, 26) for imparting relative rotational and axial motions between said piston and said cylinder block including a device for causing relative rotary motion of said spindle and spindle nut. A helical spring (46) or other resilient element is connected between said cylinder block (34) and said spindle nut (44) to compensate the reaction force generated by a pressurized fluid sample in said cylinder bore (36) when put under compresion. A flexible element (30) is connected between the piston (32) and the spindle shaft (22) to compensate for any axial misalignment of the piston and the cylinder bore. Methods for operating such a system under adiabatic, isothermal, isobaric and isochoric conditions are described. (FIG. 3).

Abstract: The present invention relates to ultrasonic resonators comprising a resonator chamber body (11) and one or more electroacoustic transducers (13, 14). The resonator body consists of a non-piezoelectric material; it forming a resonant cavity for accommodating a specimen. This resonant cavity is configured so that between the acoustically excitated internal walls a resonant wave field of standing linear acoustic waves is formed. The electroacoustic transducer(s) is(are) acoustically coupled externally to said resonator chamber body (FIG. 2) fixedly or removably or movably.

Abstract: A cell for measuring acoustical properties for fluid sample includes a stack consisting essentially of a first end piece (20), a first, wafer-shaped electro-acoustical transducer (18), a main body (12), a second electro-acoustical transducer (16) and a second end piece (22). C-shaped clamps (24) or other means are used to apply pressure on the stack. The main body (12) and the end pieces (20, 22) form axially extending, aligned cavities (14, 29, 31). The main body (12) and each end piece (20, 22) has a radial channel (28; 32) which extends from the respective cavity to an opening at a circumferential surface. A thin elastic membrane (50) tightly encloses the stack. An annular member (51) is forced in each channel opening urging a portion of the sleeve (50) into the respective channel to form a pressure resistant seal.

Abstract: A system for measuring fluid parameters of one or more liquids by an ultrasonic method comprises a voltage controlled oscillator; an ultrasonic resonator comprising one or more resonator cells, each of the resonator cells comprising an electro-acoustical transmitting transducer, an electro-acoustical receiving transducer, and a sample cavity between the transducers, wherein the transmitting transducer is connected to the output terminal of the voltage controlled oscillator; and a phase locked loop circuit comprising one of the resonator cells.

Abstract: A direct digital synthesizer (DDS) (1) or digitally operating function generator has one or more channels (A, B, . . . ) each with a phase increment register and is controlled by means of a computer system (2) (e.g. a PC) by the computer system (2) sending bits of information to the DDS.(1). Each of the phase increment registers has a given bit width and in operation at every point in time a stored phase value P. The addition of a phase increment Q of a certain bit length is achieved by specific steps in the method by means of which an overflow is avoided. In control a hardware protocol (4) with a multiplexer ensures that the bits of information sent by the computer system (2) are effective in the DDS (1) either as address bits or as data bits.