Above a certain density threshold, suspensions of rodlike colloidal particles form system-spanning networks. Using Monte Carlo simulations, we investigate how the depletion forces caused by spherical particles affect these networks in isotropic suspensions of rods. Although the depletion forces are strongly anisotropic and favor alignment of the rods, the percolation threshold of the rods decre...

Far field X-ray grating interferometry achieves extraordinary phase sensitivity in imaging weakly absorbing samples, provided that the grating period is within the transverse coherence length of the X-ray source. Here we describe a cost-efficient process to fabricate large area, 100 nm half-pitch hard X-ray phase gratings with an aspect ratio of 32. The nanometric gratings are suitable for ordi...

We describe numerical solutions of two nonpotential models of pattern formation in nonequilibrium systems to address the motion and decay of grain boundaries separating domains of stripe configurations of different orientations. We first address wave-number selection because of the boundary, and possible decay modes when the periodicity of the stripe phases is different from the selected wave n...

We present experimental evidence that, in the hard turbulence regime of Rayleigh-Bénard convection, the temperature fluctuations are produced by buoyancy, despite the presence of a mean horizontal flow at the plates. In a convection cell of aspect ratio 1, we measure the temperature time derivative for Ra from 2310 to 1310, which is skewed toward the negative in the region outside the cold ther...

We investigate the dynamics of a dimer bouncing on a vertically oscillated plate. The dimer, composed of two spheres rigidly connected by a light rod, exhibits several modes depending on initial and driving conditions. The first excited mode has a novel horizontal drift in which one end of the dimer stays on the plate during most of the cycle, while the other end bounces in phase with the plate...

We study numerically frictionless ellipse packings versus the aspect ratio alpha, and find that the jamming transition is fundamentally different from that for spherical particles. The normal mode spectra possess two gaps and three distinct branches over a range of alpha. The energy from deformations along modes in the lowest-energy branch increases quartically, not quadratically. The quartic m...

A square planar photonic crystal composed of carbon nanofibers was fabricated using e-beam lithography and chemical vapor deposition. The diffraction properties of the system were characterized experimentally and compared with theory and numerical simulations. The intensities of the (-1,0) and (-1,-1) diffraction beams were measured as functions of the angles of incidence for both s and p-polar...

We report on the dynamics and structure of the turbulent velocity field in a high-Rayleigh-number (Ra = 5.9 x 10(8))thermal convection cell with an aspect ratio of 4. Spectral density functions (measured with laser Doppler velocimetry) indicated the existence of a large-scale periodic component. The long-time mean flow field (measured with particle image velocimetry) revealed that the large-sca...

We demonstrated a new nanoassembly strategy based on capillary force-induced cohesion of high-aspect ratio nanostructures made by electron-beam lithography. Using this strategy, ordered complex pattern were fabricated from individual nanostructures at the 10 nm length scale. This method enables the formation of complex designed networks from a sparse array of nanostructures, suggesting a number...