Ultrasonic absorption and velocity measurements at mW peak power level in the range 50-500 MHz with variable pathlength cell

Uhlendorf, V.; Richmann, K. H.; Berger, W

doi:10.1088/0022-3735/18/2/013

Cited by 17 publications

(5 citation statements)

References 6 publications

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“…At the MPI another biplanar resonator was employed for measurements between 1 and 3 MHz . In the frequency ranges from 7 to 30 MHz and 80 to 400 MHz a fixed path cell and a variable path length cell, respectively, were used at the MPI to determine α from the decay in the amplitude of pulse modulated waves through the sample. The former method again yields the attenuation coefficient relative to the reference, the latter allows for absolute α measurements.…”

Section: Methodsmentioning

confidence: 99%

Kinetics of Base-Stacking Interactions and Proton Exchange of 6-Methylpurine Aqueous Solutions

et al. 2004

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Acoustical relaxation properties of aqueous solutions of 6-methylpurine have been studied using broadband ultrasonic spectrometry in the frequency range 0.2-2000 MHz. Excess attenuation with relaxation characteristics was found near the lower limit of the measuring range and also around 100 MHz. The former relaxation process has been assigned to the proton exchange of the ampholytic 6-methylpurine solutions, yielding reasonable rate constants, e.g., 1.1 × 10 3 s -1 dm 3 mol -1 for the ionization and 6 × 10 8 s -1 dm 3 mol -1 for the neutralization at neutral pH. The high frequency relaxation process has been discussed in terms of a sequential and a random isodesmic reaction scheme of stack formation. Similar rate constants have been found for both models, e.g., 5 × 10 9 and 2.5 × 10 8 s -1 for the association and dissociation constant of the sequential reaction scheme, if cooperativity effects are neglected. There are, however, indications of weak cooperativity in the stacking.

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Section: Methodsmentioning

confidence: 99%

Kinetics of Base-Stacking Interactions and Proton Exchange of 6-Methylpurine Aqueous Solutions

et al. 2004

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“…In this regard, the classical absorption of water at 25 °C is given by B = 21.2 3 10 215 s 2 m 21 . 21,22 The classical absorption is only predominate at high frequency. At low frequency, chemical relaxation is predominant causing excess absorption.…”

Section: Further Discussionmentioning

confidence: 99%

Acoustic wave detection of chemical species electrokinetically transported within a capillary tube

Prasad

2003

Analyst

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For the first time, we report the acoustic wave detection of chemical species being transported in a capillary tube to a region where acoustic coupling occurs. The measured parameter was a change in phase, which was originally only attributed to a change in solution density as the analyte passed by the detection region. Accordingly, we report the detection of change in phase as various chemical species (e.g. Cy5 dye, Cy5-derivatized glycine and underivatized glycine) were introduced into and migrated along a capillary tube through electrokinetic processes. To improve detection sensitivity, we modified various experimental parameters, such as run buffer concentration, capillary wall thickness and transducer frequency. Although acoustic wave detection was feasible, the peak width and detection limit were inadequate as compared to conventional detection methods for HPLC or CE. Nevertheless, the effects of various physical and chemical relaxation processes on acoustic wave absorption were discussed, and this has shed some light on explaining some observations, which cannot be explained by density differences alone. Accordingly, the acoustic wave method is suggested to investigate these processes, as studied in ultrasonic relaxation spectroscopy, in a flow system.

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“…Especially at very high frequencies and at an increased insertion loss of the ultrasonic ensemble, the RF driving signal (exceeding the sonic signal sometimes by 120 dB) must be reduced at the receiver input by RF switches, by a balanced transformer, by a hybrid or by a circulator. Therefore most pulsed ultrasonic transmission devices now have two piezo-electric transducers, the first solely as a transmitter, the second as a receiver (Busch and Maier 1954, Heasell and Lamb 1956, Andreae et al 1958, Andreae and Joyce 1962, Siegert 1963, Hunter and Dardy 1964, Berdyev and Lezhnev 1966, Plass 1967/68, Davidovich et al 1972, Sperkach et al 1972, Eggers and Funck 1973, Tabuchi et al 1975, Sperkach and Shakhparonov 1975, Papadakis 1976, Lezhnev 1981, Uhlendorf et al 1985, Kaatze and Lautscham 1988, Kaatze et al 1988, 1993, 1995b, Challis et al 1990, 1991. A number of differential methods increased the resolution for attenuation and velocity increments (Carstensen and Schwan 1953, Carstensen 1954b, Busse 1969/70, Corsaro et al 1970, Peters 1973, Mitaku and Sakanishi 1977, Gavish et al 1983, Elias and Eden 1979, but new electronic achievements in amplitude resolution and data storage have reduced the need for such refinements.…”

Section: Principles Of Pulse Methodsmentioning

confidence: 99%

“…base plate of the cell and the other mirror is moved together with the movable piezo-electric transducer unit. Design and characteristics of variable-pathlength cells for the VHF range (Uhlendorf et al 1985, Kaatze et al 1988, for lower frequencies (Eggers et al 1981, Kaatze et al 1993) and for higher frequencies (Kaatze and Lautscham 1988, Kaatze et al 1995b) are described in the recent literature.…”

Section: 32mentioning

confidence: 99%

Broad-band ultrasonic measurement techniques for liquids

Eggers

Kaatze

1996

Meas. Sci. Technol.

145

104

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Various methods for broad-band ultrasonic absorption and velocity measurements in liquids, using CW and pulsed signals, are reviewed. Several different ultrasonic spectrometric techniques are required to cover the wide range of liquid wavelength and attenuation values that exist in the kilohertz to gigahertz frequency range. Advantages and problems of various ultrasonic and related methods are discussed. Sonic cells for liquids and electronic equipment for spectral measurements are presented. Together with applications in relaxation spectrometry, examples of broad-band ultrasonic absorption spectra, utilizing different CW resonator and pulse-modulated travelling wave techniques, are presented.

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Ultrasonic absorption and velocity measurements at mW peak power level in the range 50-500 MHz with variable pathlength cell

Cited by 17 publications

References 6 publications

Kinetics of Base-Stacking Interactions and Proton Exchange of 6-Methylpurine Aqueous Solutions

Kinetics of Base-Stacking Interactions and Proton Exchange of 6-Methylpurine Aqueous Solutions

Acoustic wave detection of chemical species electrokinetically transported within a capillary tube

Broad-band ultrasonic measurement techniques for liquids

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