نتایج جستجو برای: temperature coefficient mixed solvent
تعداد نتایج: 858687 فیلتر نتایج به سال:
in this work, a novel and fast method for direct analysis of volatile compounds (davc) of medicinal plants has been developed by holding a filament from different parts of a plant in the gc injection port. the extraction and analysis of volatile components of a small amount of plant were carried out in one-step without any sample preparation. after optimization of temperature, extraction time a...
separation of polycyclic aromatic hydrocarbons was performed by rp-hplc using mixed micellar mobile phase. effect of temperature, types and amounts of coorganic solvent in mobile phase on efficiency, asymmetry factor and selectivity factor showed that the appropriate condition for separation of these compounds was 3% isopropanol (v/v) as co-organic solvent in mobile phase at 40°c. analysis of t...
A fluorocarbon and hydrocarbon organic solvent mixture is known as a temperature-induced phase-separation solution. When a mixed solution of tetradecafluorohexane as a fluorocarbon organic solvent and hexane as a hydrocarbon organic solvent (e.g., 71:29 volume ratio) was delivered in a capillary tube that was controlled at 10°C, the tube radial distribution phenomenon (TRDP) of the solvents was...
the complexation reactions between methylthymol blue (mtb) and co2+, ni2+, cu2+, zn2+ and pb2+ ions have been studied in different water-methanol mixtures at ph 4.45 and 25 °c by a spectrophotometric technique. the stepwise stability constants of the resulting 1:1 and 2:1 (metal ion to ligand) complexes were determined from the absorbance-mole ratio data. it was found that the overall stability...
ABsTRAcr The conditions under which the partial pressure of a solvent in the alveolar gas is likely to provide a valid index of its partial pressure in the mixed venous blood, and thus of whole-body exposure, is explored on a theoretical basis. Under steady-state conditions, providing the solvent's blood/gas partition coefficient exceeds 10, its mixed venous and alveolar pressures will agree wi...
Diffusion and sorption of Biodegradable blends of sodium alginate (SA) and lignosulphonic acid (LS) has been studied at room temperature by conventional weight gain experiments. The sorption studies of SA/LS blends are carried in pH medium of 7.4. The sorption data are used to evaluate the mass transfer coefficients such as intrinsic diffusion coefficient and permeation coefficient. It was obse...
in this study, the ion association phenomenon in the saturated solution of kcl in the mixed solvent(methanol+water) was studied. the solubility of this compound in the mixed solvent (methanol+water by value percent of methanol = 60%), and in the presence of various molarities of nano3 wasdetermined by the solvent evaporation method at 25.0°c. the results enable us to estimate the valueof thermo...
in this study, the diffusivity and volumetric mass transfer coefficients for the extraction of β-carotene from crude palm oil using co2 solvent in supercritical fluid were determined in the pressure range of 7.5-17.5 mpa and temperature range of 80-120 ºc. for this purpose, a statistical method was applied in order to minimize the number of experiments required. the volumetric mass transfer coe...
We use mixed quantum-classical molecular dynamics simulations and ultrafast transient hole-burning spectroscopy to build a molecular-level picture of the motions of solvent molecules around Na atoms in liquid tetrahydrofuran. We find that even at room temperature, the solvation of Na atoms occurs in discrete steps, with the number of solvent molecules nearest the atom changing one at a time. Th...
The amorphous polymer film swelling in a liquid solvent below the glass transition temperature was characterized by a few kinetic parameters (especially the mutual diffusion coefficient of swelling and its mean value) obtained by interference of monochromatic light in the wedge arrangement. This interferometric method allows one to determine the concentration field in the swollen surface layer ...
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