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- Axelsson, Anders, et al.
(författare)
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Determination of effective diffusion coefficients in calcium alginate gel plates with varying yeast cell content
- 1988
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Ingår i: Applied Biochemistry and Biotechnology. - 1559-0291. ; 18, s. 231-250
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Tidskriftsartikel (refereegranskat)abstract
- Effective diffusion coefficients (De) have been determined for lactose, glucose, galactose, and ethanol in calcium alginate gel with varying yeast cell concentration. The measurements have been performed in a diffusion cell, and the results evaluated with the quasisteady-state method. An ultrasonic meter was used for gel thickness determination with an accuracy of 1.5% and a new method for the reproducible preparation of gel plates was developed. It was found thatD e in pure alginate gel decreased to about 90% of the diffusivity in water and did not vary with alginate concentration.D e decreased considerably with increasing yeast cell concentration. For the solutes studied, the effective diffusion coefficient can be estimated according to the equationD e =D eo (1 - ϕ)/[1+(ϕ/2)], whereD eo is the effective diffusivity in pure gel and ϕ is the volume fraction of yeast cells.
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- Bergstrom, H, et al.
(författare)
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Two different types of hollow-cathode discharges used for high resolution laser spectroscopy on copper
- 1989
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Ingår i: Zeitschrift für Physik D Atoms, Molecules and Clusters. - 0178-7683. ; 13:3, s. 203-206
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Tidskriftsartikel (refereegranskat)abstract
- Two different techniques, Doppler-free saturation spectroscopy on a hollow-cathode discharge and fluorescence spectroscopy on a collimated atomic beam produced from a hollow-cathode discharge, have been used for high-resolution laser-spectroscopy measurements on the 3d10 4p and 5p states in neutral Copper. The relative merits of the two techniques are discussed.
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- Kröll, Stefan, et al.
(författare)
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Time-resolved laser spectroscopy on high-lying states in neutral oxygen
- 1985
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Ingår i: Physical Review Letters. - 1079-7114. ; 55:3, s. 284-287
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Tidskriftsartikel (refereegranskat)abstract
- Radiative lifetimes have been measured for five triplet states of atomic oxygen. The oxygen atoms were generated by photodissociation of NO2 and the investigated states were populated through a two-step process involving a two-photon excitation to the lowest excited triplet state of even parity, 2p33p 3P, followed by a one-photon excitation to the investigated state. A similar scheme is applicable to the study of excited states in many light atoms.
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