Density profiles of concentrated colloidal suspensions in sedimentation equilibrium

1993 ◽  
Vol 98 (9) ◽  
pp. 7330-7344 ◽  
Author(s):  
Thierry Biben ◽  
Jean‐Pierre Hansen ◽  
Jean‐Louis Barrat
Keyword(s):  
Colloidal Suspensions ◽  
Sedimentation Equilibrium ◽  
Density Profiles

Localized density profiles in binary colloidal suspensions

1993 ◽  
Vol 80 (4) ◽  
pp. 853-859 ◽  
Author(s):  
Thierry Biben ◽  
Jean-Pierre Hansen
Keyword(s):  
Colloidal Suspensions ◽  
Density Profiles

Density profiles of colloidal suspensions in equilibrium inside slit pores

1996 ◽  
Vol 87 (1) ◽  
pp. 213-226 ◽  
Author(s):  
Guillermo Rodríguez ◽  
Luis Vicente
Keyword(s):  
Colloidal Suspensions ◽  
Density Profiles ◽  
Slit Pores

scholarly journals Problem of the sedimentation equilibrium in colloidal suspensions

1934 ◽  
Vol 146 (858) ◽  
pp. 597-623 ◽  
Keyword(s):  
Thin Layer ◽  
Van Der Waals ◽  
Colloidal Suspensions ◽  
Sedimentation Equilibrium ◽  
Distribution Law ◽  
Normal Behaviour ◽  
Dispersing Medium ◽  
Repulsive Forces ◽  
Modified Equation ◽  
Number Of Particles

As is well known, in 1909, Perrin investigated the sedimentation equilibrium of colloidal suspensions and obtained a logarithmic decrease in concentration with the height, the result being confirmed by other workers. This was in agreement with the distribution law for "ideal" behaviour of the sol, log n = log n 0 + v D g d (ρ 1 - ρ 2 / k T, (1) where n and n 0 are the number of particles per cubic centrimetre at depths d of particles and dispersing medium respectively, g, k , T having their usual meaning. Costantin, however, obtained departures from this condition for n greater than 8 x 10 10 and interpreted his results in terms of repulsive forces due to the charges on the particles. Perrin modified equation (1) by assuming a law of the van der Waals' type and obtained agreement with observations up to the highest concentrations investigated ( n = 6 x 10 11 ). In all these results normal behaviour was found up to values of n greater than 10 10 . Burton, however , working with vessels about 100 cm long, has shown that the concentration is permanently uniform below a very thin layer near the upper surface.

A metal- coating Chamber for High-Resolution Cryo-SEM

1990 ◽  
Vol 48 (1) ◽  
pp. 418-419
Author(s):  
John G. Sheehan
Keyword(s):  
High Resolution ◽  
Colloidal Suspensions ◽  
Metal Coating ◽  
Colloidal Interactions ◽  
Amorphous Ice ◽  
High Vapor ◽  
Particulate Coatings ◽  
20 Nm ◽  
Film Nucleation ◽  
Coating Chamber

Improvements in particulate coatings for printable paper require understanding mechanisms of colloidal interactions in paper coating suspensions. One way to deduce colloidal interactions is to mage particle spacings and orientations at high resolution with cryo-SEM. Recent improvements in cryo-SEM technique have increased resolution enough to image particles in coating paints,vhich are sometimes smaller than 100 nm. In this report, a metal-coating chamber is described for preparation of colloidal suspensions for cryo-SEM at resolution down to 20 nm. It was found that etching is not necessary to achieve this resolution.A 120 K cryo-SEM sample will remain in an SEM for hours without noticeable condensation of imorphous ice. This is due to the high vapor pressure of vapor-condensed amorphous ice, measured by Kouchi. However, clean vacuum is required to coat samples with the thinnest possible continuous metal films which are required for high magnification SEM. Vapor contaminants, especially hrydrocarbons, are known to interfere with thin-film nucleation and growth so that more metal is needed to form continuous films, and resolution is decreased. That is why the metal-coating chamber in fig. 1 is designed for the cleanest possible vacuum. Feedthroughs for the manipulator md the shutter, which are operated during metal coating, are sealed with leak-proof stainless-steel Dellows. The transfer rod slides through a baseplate feedthrough that is double o-ring sealed.

INTERFEROMETRIC MEASUREMENTS OF DENSITY PROFILES IN LASER-TARGET INTERACTION

1979 ◽  
Vol 40 (C7) ◽  
pp. C7-767-C7-768
Author(s):  
R. Benattar ◽  
C. Popovics ◽  
R. Sigel ◽  
J. Virmont
Keyword(s):  
Laser Target ◽  
Density Profiles ◽  
Target Interaction

Preparation and Properties of Human Prothrombin Complex

1970 ◽  
Vol 24 (03/04) ◽  
pp. 325-333 ◽  
Author(s):  
G. H Tishkoff ◽  
L. C Williams ◽  
D. M Brown
Keyword(s):  
Molecular Weight ◽  
Proteolytic Enzyme ◽  
Enzyme Inhibitor ◽  
Specific Activity ◽  
Crystalline Form ◽  
Sedimentation Equilibrium ◽  
Crystalline Complex ◽  
Interaction Product ◽  
Proteolytic Enzyme Inhibitor ◽  
Purification Scheme

SummaryAs a corollary to our previous studies with bovine prothrombin, we have initiated a study of human prothrombin complex. This product has been isolated in crystalline form as a barium glycoprotein interaction product. Product yields were reduced compared to bovine product due to the increased solubility of the barium glycoprotein interaction product. On occasion the crystalline complex exhibited good yields. The specific activity of the crystalline complex was 1851 Iowa u/mg. Further purification of human prothrombin complex was made by removal of barium and by chromatography on Sephadex G-100 gels. The final product evidenced multiple procoagulant activities (II, VII, IX and X). The monomeric molecular weight determined by sedimentation equilibrium in a solvent of 6 M guanidine-HCl and 0.5% mercaptoethanol was 70,191 ± 3,057 and was homogeneous with respect to molecular weight. This product was characterized in regard to physical constants and chemical composition. In general, the molecular properties of human prothrombin complex are very similar to the comparable bovine product. In some preparations a reversible proteolytic enzyme inhibitor (p-aminophenylarsonic acid) was employed in the ultrafiltration step of the purification scheme to inhibit protein degradation.

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