نتایج جستجو برای: gelation time
تعداد نتایج: 1894456 فیلتر نتایج به سال:
A new class of fluorescent organogelators, pyrene-containing poly(arylene ether sulfone)s, showed two fluorescence switching modes in different gelation solvents. The THF gel exhibited excimer emission due to dimerization of the pyrene groups. In contrast, excimer emission was quenched after gelation in MC because of stacking among the pyrene groups.
This paper is devoted to the analysis of a numerical scheme for the coagulation and fragmentation equation. A time explicit finite volume scheme is developed, based on a conservative formulation of the equation. It is shown to converge under a stability condition on the time step, while a first order rate of convergence is established and an explicit error estimate is given. Finally, several nu...
Instantaneous gelation in the addition model with superlinear rate coe cients is investigated. The conjectured post-gelation solution is shown to arise naturally as the limit of solutions to some nite approximations as the number of equations grows to in nity. Non-existence of continuous solutions to the addition model is also established in that case.
A new gelator was discovered by identifying molecular scaffolds exhibiting 1D intermolecular interactions in the solid-state and synthesizing derivatives. Gelation can be triggered by adding Hg(OAc)(2) to a precursor molecule. The in situ gelation is selective for Hg(2+) over other metals.
A novel chiral coordination polymeric gel based on an amino acid derived symmetrical ligand, specific base, and Zn(2+) has been described. Zn(2+) induced conformational reorganization in the ligand leads to gelation via J-aggregated helical fibres. The vital role played by π-π stacking in gelation has been monitored by fluorescence and NMR spectroscopy.
It was found that CO2 could induce the gelation of Pluronic aqueous solutions, during which the microstructure of the solution transforms from randomly dispersed spherical micelles to cubic close packed micelles. The gelation switched by compressed CO2 has many advantages and can be applied in the synthesis of porous materials.
Highly homogeneous transparent titania gels have been successfully prepared from titanium alkoxide by a sol–gel method utilizing chelating agent, ethyl acetylacetate (EtAcAc), in the presence of strong acid anions. Only catalytic amount of a strong acid anion suppress the rapid hydrolysis of titanium alkoxide by blocking the nucleophilic attack of HO and H2O, and the resultant moderate sol–gel ...
The present work investigated the preparation of biodegradable beads with alginate polymer by ionotropic gelation method to improve the control release properties of the antibiotic rifampicin. Ionotropic gelation method was applied to prepare beads using calcium chloride (CaCl2) as cationic component and alginate as an anionic component. In this method, adding 0.5% w/v polyvinyl alcohol (PVA) t...
An open coaxial re-entrant microwave sensor has been used for the non-invasive and continuous monitoring of the sol-gel transition of physical gels characterized by different gelation mechanisms, solvents, compositions, and stabilities. Comparison of measurements by differential scanning calorimetry allowed the identification of the phase transition by a change in the dielectric properties of t...
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