Energy resolution and related charge carrier mobility in LaBr3:Ce scintillators

The scintillation response of LaBr3:Ce scintillation crystals was studied as function of temperature and Ce concentration with synchrotron X-rays between 9?keV and 100?keV. The results were analyzed using the theory of carrier transport in wide band gap semiconductors to gain new insights into charge carrier generation, diffusion, and capture...

Exchange magnetic field torques in YIG/Pt bilayers observed by the spin-Hall magnetoresistance

The effective field torque of an yttrium-iron-garnet (YIG) film on the spin accumulation in an attached platinum (Pt) film is measured by the spin-Hall magnetoresistance (SMR). As a result, the magnetization direction of a ferromagnetic insulating layer can be measured electrically. Experimental transverse and longitudinal resistances are well...

Substrate-dependent kinetics in tyrosinase-based biosensing: Amperometry vs. spectrophotometry

Despite the broad use of enzymes in electroanalytical biosensors, the influence of enzyme kinetics on the function of prototype sensors is often overlooked or neglected. In the present study, we employ amperometry as an alternative or complementary method to study the kinetics of tyrosinase, whose catalytic activity results in o-quinone products...

Electron-beam-induced deposition of 3-nm-half-pitch patterns on bulk Si

This paper demonstrates electron-beam-induced deposition of few-nm-width dense features on bulk samples by using a scanning electron-beam lithography system. To optimize the resultant features, three steps were taken: (1) features were exposed in a repetitive sequence, so as to build up the deposited features gradually across the entire pattern,...

Thermal stability of gas phase magnesium nanoparticles

In this work we present a unique transmission electron microscopy study of the thermal stability of gas phase synthesized Mg nanoparticles, which have attracted strong interest as high capacity hydrogen storage materials. Indeed, Mg nanoparticles with a MgO shell ( ? 3?nm thick) annealed at 300?°C show evaporation, void formation, and void...

The Role of Coherency Strains on Phase Stability in LixFePO4: Needle Crystallites Minimize Coherency Strain and Overpotential

We investigate the role of coherency strains on the thermodynamics of two-phase coexistence during Li (de)intercalation of LixFePO4. We explicitly account for the anisotropy of the elastic moduli and analytically derive coupled chemical and mechanical equilibrium criteria for two-phase morphologies observed experimentally. Coherent two-phase...

Hydrogen vacancies facilitate hydrogen transport kinetics in sodium hydride nanocrystallites

We report ab initio calculations based on density-functional theory, of the vacancy-mediated hydrogen migration energy in bulk NaH and near the NaH(001) surface. The estimated rate of the vacancy mediated hydrogen transport, obtained within a hopping diffusion model, is consistent with the reaction rates of H-D exchange in nano-NaH at the...

An experimental study on the molecular organization and exciton diffusion in a bilayer of a porphyrin and poly(3-hexylthiophene)

The exciton root-mean-square displacement (?D) in regioregular poly(3-hexylthiophene) (P3HT) deposited onto meso-tetrakis (n-methyl-4-pyridyl) porphyrin tetrachloride (H2TMPyP) has been determined from the photovoltaic response of a device based on these materials in a bilayer configuration. Excitons formed on illumination that reach the...

Brownian particles in transient polymer networks

We discuss the thermal motion of colloidal particles in transient polymer networks. For particles that are physically bound to the surrounding chains, light-scattering experiments reveal that the submillisecond dynamics changes from diffusive to Rouse-like upon crossing the network formation threshold. Particles that are not bound do not show...

The stress generated by non-Brownian fibers in turbulent channel flow simulations

Turbulent fiber suspension channel flow is studied using direct numerical simulation. The effect of the fibers on the fluid mechanics is governed by a stress tensor, involving the distribution of fiber position and orientation. Properties of this function in channel flow are studied by computing the trajectories and orientations of individual...

Collective diffusion coefficient of proteins with hydrodynamic, electrostatic, and adhesive interactions

A theory is presented for ?C, the coefficient of the first-order correction in the density of the collective diffusion coefficient, for protein spheres interacting by electrostatic and adhesive forces. An extensive numerical analysis of the Stokesian hydrodynamics of two moving spheres is given so as to gauge the precise impact of lubrication...

Water diffusion through a membrane protein channel: A first passage time approach

Water diffusion through OmpF, a porin in the outer membrane of Escherichia coli, is studied by molecular dynamics simulation. A first passage time approach allows characterizing the diffusive properties of a well-defined region of this channel. A carbon nanotube, which is considerably more homogeneous, serves as a model to validate the...

Impedance Simulation of a Li-Ion Battery with Porous Electrodes and Spherical Li+ Intercalation Particles

We present a semimathematical model for the simulation of the impedance spectra of a rechargeable lithium batteries consisting of porous electrodes with spherical Li+ intercalation particles. The particles are considered to have two distinct homogeneous phases as a result of the intercalation and deintercalation of Li+ during charge and...

Knudsen self- and Fickian diffusion in rough nanoporous media

The effect of pore surface roughness on Knudsen diffusion in nanoporous media is investigated by dynamic Monte Carlo simulations and analytical calculations. A conceptual difference is found between the roughness dependence of the macroscopic, transport diffusivity and the microscopic, self-diffusivity, which is reminiscent of diffusion in...