Thank Bert very much,
I've found theses books that you advise, i works in a laboratory so it's quite easy to find this type of book.
Thanks again for your all answers. I'll return to ask for your help :D.
: --Previous Message--
: Hi Bert,
: It's me again, :D
: I'm looking for the curve of permittivity (epsilon' )and loss
: index(epsilon")of water in function of frequency (in particular in
: lower frequency: MHz until mHz).
: But i only found this spectrum in high frequency region (MHz to GHz).
: I hope that you know that somewhere and give me some advises
: Thanks alot
: Hello Tim,
: As you are probably already aware, water's permittivity and dispersion
: loss vary with frequency, E-field strength, temperature, pressure, and
: even with externally applied magnetic fields. And of course, everything
: changes again when water freezes. Water is really a very interesting polar
: liquid - how interesting can be gleaned from the following site that
: discusses (and explains) 41 different anomalies of water:
: There are a couple of books that may help you in your quest. Although they
: are both out of print, they should still be available through university
: library loan programs. The titles are:
: Coelho, Roland J.,”Physics of Dielectrics for the Engineer”, Elsevier,
: 1978, 175p, ISBN 0444417559
: Hasted, J. B., “Aqueous Dielectrics”, Chapman & Hall, 1973, 302pp, HC,
: ISBN 0412098008. The identical book was also published in the USA by John
: Wiley and Sons as ISBN 0470358882
: If you have access to published scientific literature, here's an excellent
: 18 page article which covers the the real and imaginary portions (e' and
: e") of the dielectric constant for pure deionized water in the range
: of 20 Hz - 1 MHz using regular brass and blocking electrodes (to eliminate
: space charge double-layer effects at the electrodes). It also compares the
: results for various purities of water as well as various concentrations of
: "Space-charge dielectric properties of water and aqueous
: electrolytes", Journal of Molecular Liquids, Volume 69, July 1996,
: Pages 183-200, by D. G. Frood and T. J. Gallagher.
: Frood and Gallagher used brass electrodes and a precision LCR meter to
: measure de-ionized water. They found that the real portion of the
: dielectric constant (due mainly to space charge double layer effects) was
: as high as 10e5 - 10e6 at low frequencies, dropping down to the normally
: quoted range of ~80 at higher (~10 kHz) frequencies. A similar effect was
: found for the dielectric loss, which was as high as 10e6 - 10e7 at low
: frequencies due to conduction effects, decreasing inversely with frequency
: (through the entire frequency range studied) to about 20 at 1 MHz. They
: then compare the results using insulated ("blocking") electrodes
: to remove double layer effects.The latter results show a slowly rising
: peak in dissipation factor of 0.8 at about 500 kHz. The measured
: capacitance stayed approximately level until 10e4 Hz, then declined
: through the range of 10e4 - 0.5x10e7 Hz, leveling off to a much lower
: value (about 20% of the initial value seen below 10e4 Hz).
: If you have difficulty obtaining the article, please contact me directly
: at my email address.
: Good luck and best regards,
: -- Bert --