نتایج جستجو برای: ultra dispersions
تعداد نتایج: 64127 فیلتر نتایج به سال:
Accurate approximate relations for the e}ective elastic moduli of two! and three!dimensional isotropic dispersions are obtained by truncating\ after third!order terms\ an exact series expansion for the e}ective sti}ness tensor of d!dimensional two!phase composites "obtained in the _rst paper# that perturbs about certain optimal dispersions[ Our third!order approximations of the e}ective bulk mo...
Dispersions of poly(methyl methacrylate) (PMMA) latexes were prepared in a low dielectric, nonpolar solvent (dodecane) both with and without the oil-soluble electrolyte, tetradodecylammonium-tetrakis(3,5-bis(trifluoromethyl)phenyl)borate. For dispersions with a high concentration of background electrolyte, the latexes become colloidally unstable and sediment in a short period of time (<1 h). Th...
Application of novel chitosan derivatives in dissolution enhancement of a poorly water soluble drug.
Solid dispersions of the poorly water soluble drug dexamethasone and newly synthesized chitosan derivatives (chitosan succinate, CS, and chitosan phthalate, CP) were prepared by spray drying. The resulting microspheres were evaluated in terms of their drug loading or encapsulation efficiency as well as drug release profile. Differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD...
The mechanisms by which pulmonary surfactant protein B (SP-B) affects the surface activity of surfactant lipids are unclear. We have studied the peptide/lipid interactions of the amino-terminal amphipathic domain of SP-B by comparing the secondary conformations and surface activities of a family of synthetic peptides based on the native human SP-B sequence, modified by site-specific amino acid ...
Gel sheets prepared from high-viscosity aqueous dispersions of hydrolyzed starch-polyacrylonitrile graft copolymers absorb several hundred times their own weight in water. Viscosity of the disperSiOns can be . reduced to low levels by mechanical shear before the films are cast to give solutions which yield water'soluble .films. These soluble films can be readily cross-linked to again form highl...
We develop rigorous bounds on the effective thermal conductivity se of dispersions that are given in terms of the phase contrast between the inclusions and matrix, the interface strength, volume fraction, and higher-order morphological information, including interfacial statistics. The new bounds give remarkably accurate predictions of the thermal conductivity of dispersions of metallic particl...
Experimental rheological aspects of colloidal dispersions are now being investigated with improved skills and with better defined model systems. New methods allow more detailed investigations. The relationship between the rheological macroproperties, microproperties and processes is the focus of the most recent investigations. Better insight has been gained concerning this relationship. type of...
We present a comparison of experimentally and theoretically determined osmotic pressures for various colloidal dispersions. Experimental data is collected from several different silica and polystyrene dispersions. The theoretical pressure determinations are based on the Primitive Model combined with the Cell Model and the physical quantities are calculated exactly using Monte Carlo simulations ...
Organic nanoparticles of poly(styrene-co-maleimide) or SMI were synthesized in aqueous dispersion with a maximum concentration of 35 wt.% and are favorably applied in industrial coating processes. In order to evaluate the further processability and flow behavior of these nanoparticle dispersions, general rheological characterization under creep, oscillatory and rotational testing was done by ap...
The influence of preparation methodology of silymarin solid dispersions using a hydrophilic polymer on the dissolution performance of silymarin was investigated. Silymarin solid dispersions were prepared using HPMC E 15LV by kneading, spray drying and co-precipitation methods and characterized by FTIR, DSC, XRPD and SEM. Dissolution profiles were compared by statistical and model independent me...
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