A Computer‐controlled System of Transmission Lines for the Determination of the Complex Permittivity of Lossy Liquids between 8.5 and 90 GHz

Barthel, J.; Bachhuber, K.; Buchner, Richard; Hetzenauer, H.; Kleebauer, M.

doi:10.1002/bbpc.19910950802

Cited by 106 publications

(42 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…All VNA spectra were recorded using at least two independent calibrations (with air, water and mercury as the standards). Higher frequency data for selected solutions were recorded at Regensburg using two waveguide interferometers (IFMs): A-band (27 6 m (GHz) 6 39) and E-band (60 6 m (GHz) 6 89) at approximately 10 selected frequencies as described in detail previously (Barthel et al, 1991). Temperature control and accuracy were similar to those at Murdoch.…”

Section: Methodsmentioning

confidence: 99%

Ion association and hydration in 3:2 electrolyte solutions by dielectric spectroscopy: Aluminum sulfate

Schrödle

Rudolph

Hefter

et al. 2007

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

Section: Methodsmentioning

confidence: 99%

Ion association and hydration in 3:2 electrolyte solutions by dielectric spectroscopy: Aluminum sulfate

Schrödle

Rudolph

Hefter

et al. 2007

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

“…[36] for frequencies between 100-500 GHz, but we did not go beyond 500 GHz. Below 100 GHz, we have included the measurements by Barthel et al at 25 C [37]. The only measurements for supercooled water were done by Bertolini et al at 9.61 GHz and comprise the temperature range between C and C [33].…”

Section: A Two Debye Relaxation Fits For Pure Watermentioning

confidence: 99%

The complex dielectric constant of pure and sea water from microwave satellite observations

Meißner

Wentz

2004

IEEE Trans. Geosci. Remote Sensing

647

420

View full text Add to dashboard Cite

Abstract-We provide a new fit for the microwave complex dielectric constant of water in the salinity range between 0-40 ppt using two Debye relaxation wavelengths. For pure water, the fit is based on laboratory measurements in the temperature range between 20 C and +40 C including supercooled water and for frequencies up to 500 GHz. For sea water, our fit is valid for temperatures between 2 C and +29 C and for frequencies up to at least 90 GHz. At low frequencies, our new model is a modified version of the Klein-Swift model. We compare the results of the new fit with various other models and provide a validation using an extensive analysis of brightness temperatures from the Special Sensor Microwave Imager.Index Terms-Dielectric constant of pure and sea water, microwave radiometers, ocean surface emissivity, permittivity, Special Sensor Microwave/Imager (SSM/I).

show abstract

“…15 The VNA was calibrated with air/mercury/water (open/short/load) and the raw data corrected with a Padé calibration using water, propylene carbonate, N,Ndimethylacetamide, and benzonitrile as secondary standards. 16 Samples were obtained by diluting a stock solution of c = 4.398 mol/L.…”

Section: Fig 1 (Color Online)mentioning

confidence: 99%

Glasslike behavior in aqueous electrolyte solutions

Turton

Hunger

Hefter

et al. 2008

The Journal of Chemical Physics

111

162

View full text Add to dashboard Cite

When salts are added to water, the viscosity generally increases suggesting the ions increase the strength of the water's hydrogen-bond network. However, infrared pump-probe measurements on electrolyte solutions have found that ions have no influence on the rotational dynamics of water molecules implying no enhancement or breakdown of the hydrogen-bond network. Here we report optical Kerr-effect and dielectric relaxation spectroscopic measurements, which have enabled us to separate the effects of rotational and transitional motions of the water molecules. These data show that electrolyte solutions behave like a supercooled liquid approaching a glass transition in which rotational and translational molecular motions are decoupled. It is now possible to understand previously conflicting viscosity data, nuclear magnetic resonance relaxation, and ultrafast infrared spectroscopy in a single unified picture.It is well known that when salts are added to water the viscosity typically increases, suggesting that the ions alter the hydrogen-bond network of the water, 1 which appears to be confirmed by, for example, neutron diffraction experiments. 2 However, recent ultrafast infrared pump-probe measurements on electrolyte solutions have found that ions do not influence the rotational dynamics of water molecules suggesting that there is no enhancement or breakdown of the hydrogen-bond network in liquid water. 3 As the effect of ions and ionic moieties on the structure of water is important for understanding protein stability, enzymatic reactions, and substrate binding, it is crucial to resolve this paradox. 4 Here we report ultrafast optical Kerr effect 5 (OKE) and dielectric relaxation 6 (DR) spectroscopy measurements, which show that salt solutions behave like a supercooled liquid approaching a glass transition, where rotational and translational molecular motions become decoupled. The rotational motions of bulk water molecules -observed as an -relaxation in DR -are essentially independent of concentration. The translational motions seen in OKE spectroscopy can be understood as a -relaxation 7 and their dynamics become increasingly inhomogeneous with increasing salt concentration. This insight reconciles previously conflicting viscosity data, 8 nuclear magnetic resonance relaxation, 9 and ultrafast infrared spectroscopy 3 data in a single unifying picture.When simple inorganic salts are added to water, the viscosity typically increases ( see FIG. 1). In the relatively low concentration range (up to ~0.5 M), this is described by the semi-empirical Jones-Dole equation, 1 , which expresses the shear viscosity in terms of the viscosity of pure water 0 , salt concentration c, and parameters A and B. For many salts additional terms have to be added to describe the rapid increase in viscosity at higher concentrations. The obvious conclusion to draw from this behavior is that ions alter the structure of water. Indeed, the empirical Jones-Dole B coefficient is often used to classify ions as either structure makers (kosmotropes...

show abstract

A Computer‐controlled System of Transmission Lines for the Determination of the Complex Permittivity of Lossy Liquids between 8.5 and 90 GHz

Cited by 106 publications

References 15 publications

Ion association and hydration in 3:2 electrolyte solutions by dielectric spectroscopy: Aluminum sulfate

Ion association and hydration in 3:2 electrolyte solutions by dielectric spectroscopy: Aluminum sulfate

The complex dielectric constant of pure and sea water from microwave satellite observations

Glasslike behavior in aqueous electrolyte solutions

Contact Info

Product

Resources

About