1208
2003
eng
postprint
0
2007-04-20
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Optical sensing with photon density waves: investigation of model media
Investigations with frequency domain photon density waves allow elucidation of absorption and scattering properties of turbid media. The temporal and spatial propagation of intensity modulated light with frequencies up to more than 1 GHz can be described by the P1 approximation to the Boltzmann transport equation. In this study, we establish requirements for the appropriate choice of turbid model media and characterize mixtures of isosulfan blue as absorber and polystyrene beads as scatterer. For these model media, the independent determination of absorption and reduced scattering coefficients over large absorber and scatterer concentration ranges is demonstrated with a frequency domain photon density wave spectrometer employing intensity and phase measurements at various modulation frequencies.
urn:nbn:de:kobv:517-opus-13147
1314
Physical chemistry, chemical physics : PCCP ; a journal of European chemical societies. - ISSN 1463-9076. - 5 (2003), p. 5182 - 5187
<hr>
first published in:<br><a href="http://www.rsc.org/publishing/journals/CP/">Physical chemistry, chemical physics</a> : PCCP ; a journal of European chemical societies. - ISSN 1463-9076. - 5 (2003), S. 5182 - 5187<br>doi: <a href="http://dx.doi.org/10.1039/b308630e">10.1039/b308630e</a><br>
Reproduced by permission of the PCCP Owner Societies
-
Oliver Reich
Hans-Gerd Löhmannsröben
Frank Schael
Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
paper 026
Chemie und zugeordnete Wissenschaften
open_access
Institut für Chemie
Extern
Universität Potsdam
https://publishup.uni-potsdam.de/files/1208/Reich2003.pdf
17975
2001
2001
deu
article
1
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Optische Sensorik für die in-situ-Analytik von Brauprozessen
allegro:1991-2014
10092590
Chemie - Ingenieur - Technik. - 73 (2001), 4, S. 381 - 384
Frank Schael
Sonja Engelhard
Oliver Reich
Institut für Chemie
Institut für Physikalische Chemie und Theoretische Chemie
17976
2001
2001
deu
article
1
--
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In-situ-Analytik heterogener Medien mit frequenz- und leistungsmodulierten Diodenlasern
Electronic intensity and frequency modulation of diode lasers enables new perspectives for highly sensitive analytical in-situ techniques. For analyis of "heterogeneous" media, which may consist of coexisting gaseous, liquid, and solid phases and often show multiple light scattering, non-invasive techniques with outstanding performance characteristics can be developed. Analysis of photon density waves launched by intensity-modulated lasers provide an elegant way for the determination of absorption and scattering coefficients of multiple scattering media. The absorption coefficient can be used for qualitative and quantitative analysis of chemical constituents (which absorb in the range of the laser wavelengths). The scattering coefficient allows characterization of physical and morphological properties of the sample. In the current work, applicability of appropriate radiation transport models was investigated with simple light scattering solutions and compared with results obtained from the treatment according to the theory of Kubelka and Munk. Measurements of human blood samples are discussed. A new method for determination of water vapor partial pressure in a polyurethane foam with a frequency-modulated external cavity diode laser is discussed.
allegro:1991-2014
10092591
Technisches Messen. - 68 (2001), 10, S. 448 - 455
Frank Schael
Oliver Reich
Institut für Chemie
Institut für Physikalische Chemie und Theoretische Chemie
19829
2000
2000
eng
article
1
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Near infrared diode laser spectroscopy of organic compounds in turbid aqueous solutions
Diffuse reflectance measurements and photon migration studies with near infrared (NIR) diode lasers were employed to elucidate experimental methods for determining absorption and scattering coefficients and species concentrations in highly scattering solutions. Applicability of theoretical approaches were established by investigating model systems with absorbing (e.g. ink, malachite green) and scattering (e.g. milk powder, caolinit) species in aqueous solution. While diffuse reflectance measurements practically requires calibration procedures, photon migration studies allow quantitative determination of absorption and scattering coefficients of turbid solutions consistent with absorptions coefficients obtained from Lambert-Beer's law. Furthermore, NIR absorption spectra of water, chlorinated hydrocarbons (chloroform, 1,2-dichloroethane, trichloroethene) and of various sugars ($alpha$-D-glucose, sucrose, maltose) are discussed. Spectral variations of NIR water absorption with temperature and solvents are exammined. Exemplary, NIR diode laser detection of water in acetone/water mixtures is performed.
0-9528666-1-7
allegro:1991-2014
10092589
Near infrared spectroscopy : proceedings of the 9th conference / Hrsg.: Anthony M. C. Davies ; Roberto Giangiacomo. - Chichester : NIR Publications, 2000. - ISBN 0-9528666-1-7. - S. 183 - 189
Frank Schael
Oliver Reich
Hans-Gerd Löhmannsröben
Institut für Chemie
Institut für Physikalische Chemie und Theoretische Chemie
19431
2000
2000
deu
article
1
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Untersuchung von organischer Bodensubstanz und Bodengasen mit laser-spektroskopischer in-situ Meßtechnik
allegro:1991-2014
10090667
Brandenburgische UmweltBerichte. - 8 (2000), S. 205 - 206
Hans-Gerd Löhmannsröben
Frank Schael
Oliver Reich
Matthias Lemke
Lars Schober
Institut für Chemie
Institut für Physikalische Chemie und Theoretische Chemie
335
2000
deu
176
227
bookpart
Brandenburgisches Umweltforschungszentrum
0
2005-05-24
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Umweltforschung für das Land Brandenburg : Projekt Umweltanalytik / Umweltmeßtechnik / Informationssysteme
urn:nbn:de:kobv:517-opus-3862
386
Brandenburgische Umwelt-Berichte : BUB ; Schriftenreihe des Zentrums für Umweltwissenschaften der Universität Potsdam und des Brandenburgischen Umweltforschungszentrums, Neuruppin. - 8 (2000)
AR 11100
Hartmut Asche
Christine Böckmann
Steffen Laue
Hans-Gerd Löhmannsröben
Matthias Lemke
Lars Schober
Oliver Reich
Erika Lück
Marc Schütte
Horst Domsch
Alexander Makower
Frieder W. Scheller
Wolfgang Stöcklein
Ursula Wollenberger
Rainer Schultze
Theo Hengstermann
Frank Schael
Naturwissenschaften und Mathematik
open_access
Extern
Zentrum für Umweltwissenschaften
Universität Potsdam
https://publishup.uni-potsdam.de/files/335/bub8_s176-227.pdf