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The adsorption equilibrium and kinetics of N-lauroyl- N-methylglucamide (MEGA-12) aqueous solution were studied. The critical micelle concentration, the maximum surface excess, and the minimum area per molecule of MEGA-12 were obtained as 2.48 × 10−4 mol/l, 4.883 × 10−6 mol/m2, and 0.34 nm2, respectively. The adsorption kinetics of MEGA-12 was studied by the maximum bubble pressure method. The result shows that in the initial stage or at small MEGA-12 concentrations, the adsorption process is diffusion-controlled; however, it changes to become adsorption-controlled at the end of the process. The effects of temperature, inorganic salts, alcohols, and ionic liquid on the adsorption kinetics were also discussed. [ABSTRACT FROM AUTHOR]

The dynamic stability of an axially accelerating viscoelastic beam with two fixed supports is investigated. The Kelvin model is used for the constitutive law of the beam. A small simple harmonic is allowed to fluctuate about the constant mean speed applied to the beam, and the governing equation is truncated using the Galerkin method based on the eigenfunctions of the stationary beam. The averaged equations are derived for the cases of subharmonic and combination resonance. Finally, numerical examples are presented to demonstrate the effects of the viscosity coefficient, the mean axial speed and the beam bending stiffness on the stability boundaries. [ABSTRACT FROM AUTHOR]

The recombination kinetics of Te isoelectronic centers in ZnS1-xTex (0.0065≤x≤0.85) alloys is studied by time-resolved photoluminescence (TRPL) at low temperature. The measured radiative recombination lifetimes of different Te bound exciton states are quite different, varying from a few nanoseconds to tens of nanosecond. As the bound exciton state evolves from a single Te impurity (Te1) to larger Te clusters (Ten,n=2,3,4), the recombination lifetime increases. It reaches maximum (∼40 ns) for the Te4 bound states at x=0.155. The increase of the exciton lifetime is attributed to the increasing exciton localization effect caused by larger localization potential. In the large Te composition range (x>0.155), the exciton recombination lifetime decreases monotonically with Te composition. It is mainly due to the hybridization between the Te localized states and the host valence band states. The composition dependences of the exciton binding energy and the photoluminescence (PL) line width show the similar tendency that further support the localization picture obtained from the TRPL measurement. [ABSTRACT FROM AUTHOR]