Graphene-enhanced Raman scattering (GERS) spectra and coherent anti-Stokes Raman scattering (CARS) of thymine molecules adsorbed on a single-layer graphene were studied. The enhancement factor was shown to depend on the molecular groups of thymine. In the GERS spectra of thymine, the main bands are shifted with respect to those for molecules adsorbed on a glass surface, indicating charge transf...

A fluorescence correlation spectroscopy experiment that combines two-photon excitation and a standing-wave interference pattern is presented. The experimental correlation function can be analyzed using a simple expression involving (1) an exponential decay with time constant tau(f), which reflects diffusion across the interference fringes, and (2) a longer-lived decay with time constant tau(ome...

The structure and dynamics of three-dimensional foams are probed quantitatively by exploiting the strong multiple scattering of light that gives foams their familiar white color. Approximating the propagation of light as a diffusion process, transmission measurements provide a direct probe of the average bubble size. A model for dynamic light scattering is developed that can be used to interpre...

We synthesize a series of block copolymers comprising a polystyrene (PS) block and an imidazolium-functionalized PS (IL) block and characterize their assembly properties. We use small-angle neutron scattering and dynamic light scattering to determine the micelle size and shape in dilute solutions and to assess the micelle interactions in concentrated solutions. By studying a series of copolymer...

To match the NBER business cycle features it is necessary to employ Generalised dynamic categorical (GDC) models that impose certain phase restrictions and permit multiple indexes. Theory suggests additional shape restrictions in the form of monotonicity and boundedness of certain transition probabilities. Maximum likelihood and constraint weighted bootstrap estimators are developed to impose t...

We use time-resolved x-ray photon correlation spectroscopy to investigate the slow dynamics of colloidal gels made of moderately attractive carbon black particles. We show that the slow dynamics is temporally heterogeneous and quantify its fluctuations by measuring the variance chi of the instantaneous intensity correlation function. The amplitude of dynamical fluctuations has a nonmonotonic de...

A novel technique for the localization of stimulated Brillouin scattering (SBS) interaction is proposed, analyzed and demonstrated experimentally. The method relies on the phase modulation of two counter-propagating optical waves by a common pseudo-random bit sequence (PRBS), these waves being spectrally detuned by the Brillouin frequency shift. The PRBS symbol duration is much shorter than the...

We investigate the time-dependent nonlinear optical absorption of a clay dispersion (Laponite) in an organic dye (rhodamine B) water solution displaying liquid-arrested state transition. Specifically, we determine the characteristic time tauD of the nonlinear susceptibility buildup due to the Soret effect. By comparing tauD with the relaxation time provided by standard dynamic light scattering ...

Pressure-induced dissociation of a turbid solution of casein micelles was studied in situ in static and dynamic light scattering experiments. We show that at high pressure casein micelles decompose into small fragments comparable in size to casein monomers. At intermediate pressure we observe particles measuring 15 to 20 nm in diameter. The stability against pressure dissociation increased with...

We report time-resolved small angle neutron scattering (t-SANS) measurements of the topological relaxation of Couette shear-induced stacked L(alpha) lamellar states to their multiconnected isotropic L3 sponge equilibrium phases in a surfactant bilayer membrane system. Comparison of this structural relaxation time to the interval between diffusive membrane contacts, as determined from dynamic li...