Different methods of investigation of the spin-echo attenuation, in the NMR pulsed field gradient experiments, were analyzed in order to optimize the measurements of the self-diffusion coefficient of the small molecules of simplest liquids. A particular algorithm of representation of the experimental data is proposed in order to eliminate the effect of the residual gradient. This algorithm, tested for pure water, give results in accord with the literature.
The self-diffusion coefficient of the cyclohexane in some polybutadiene solutions was measured by NMR pulse magnetic field gradient method. The experimental data were analyzed on the basis of the free volume theory. A specific algorithm for analyze was proposed. Preliminary investigation indicates a deviation from the WLF theory for these solutions.
The self-diffusivity tensor in homogeneously sheared dense granular flows is anisotropic. We show how its components depend on solid fraction, restitution coefficient, shear rate, and granular temperature.
AbstractAggregation numbers were calculated based on measurements of the self-diffusion coefficients, the effective hydrodynamic radii of micelles and aggregates of oxyethylated alkylphenols in aqueous solutions. On the assumption that the radii of spherical micelles are equal to the lengths of fully extended neonol molecules, the limiting values of aggregation numbers corresponding to spherically shaped neonol micelles were calculated. The concentration and temperature ranges under which spherical micelles of neonols are formed were determined.
Temperature and pressure have direct and remarkable implications for drying and dewatering effect of low rank coals such as lignite. To understand the microenergy change mechanism of lignite, the molecular dynamics simulation method was performed to study the self-diffusion of lignite/water under different temperatures and pressure. The results showed that high temperature and high pressure can promote the diffusion of lignite/water system, which facilitates the drying and dewatering of lignite. The volume and density of lignite/water system will increase and decrease with temperature increasing, respectively. Though the pressure within simulation range can make lignite density increase, the increasing pressure showed a weak impact on variation of density.
Optimizing the
self‐assembly
of conjugated polymers and small molecules through structurally programmed
non‐covalent
control