[show abstract][hide abstract] ABSTRACT: Measurements of the diffusion coefficient, the sedimentation constant and the turbidity by dynamic light scattering, ultracentrifugation and turbidimetry, respectively, of a charged silica sol as a function of the colloid concentration are reported. The strong repulsive interparticle interactions give rise to a spectacular increase of the inverse osmotic compressibility with concentration. It is found that the generalized Einstein relation between the sedimentation and diffusion coefficients and the osmotic compressibility is satisfied, within the experimental accuracies, at finite concentrations.
The Journal of Chemical Physics 01/1985; · 3.16 Impact Factor
[show abstract][hide abstract] ABSTRACT: The diffusion coefficient of a water-in-oil microemulsion has been measured as a function of the concentration of the suspended particles using photon correlation techniques. The data have been analysed using an extension of the thermo-hydrodynamic theory of G. K. Batchelor to the case of a potential of mean force between particles which consists of a hard-core repulsion and an attractive part. The parameters for this potential are consistent with those obtained from the osmotic compressibility as determined by static light scattering.
Journal of the Chemical Society Faraday Transactions 2 01/1980;
[show abstract][hide abstract] ABSTRACT: In this contribution we investigate the applicability of photon correlation techniques as a clinical tool for the evaluation of motility parameters of undiluted human sperm. Measurements on semen samples, selected visually for ‘good’ motility, yielded reproducible estimates of the fraction motile spermatozoa and the mean speed of the motile cells.
Journal of Modern Optics - J MOD OPTIC. 01/1980; 27(1):25-30.
[show abstract][hide abstract] ABSTRACT: The application of photon correlation spectroscopy for the evaluation of motility parameters of undiluted human sperm is investigated. Measurements on semen samples, selected visually as good (i.e., fraction motile spermatozoa larger than 0.6 and a positive appreciation of the motion), gave estimates of the fraction motile spermatozoa, reproducible within 10%, and of the mean velocity of the motile cells, reproducible within 5%.