We have previously introduced an anisotropic leaky-mode modulator as a waveguide-based, acousto-optic solution for spatial light modulation in holographic video display systems. Waveguide fabrication for these and similar surface acoustic wave devices relies on proton exchange of a lithium niobate substrate, which involves the immersion of the substrate in an acid melt. While simple and effecti...

The acid-activated proton channel formed by the influenza M2 protein is important for the life cycle of the virus. A single histidine, His37, in the M2 transmembrane domain (M2TM) is responsible for pH activation and proton selectivity of the channel. Recent studies suggested three models for how His37 mediates proton transport: a shuttle mechanism involving His37 protonation and deprotonation,...

Events with a baryon carrying a large fraction of the proton beam energy have been observed in ep scattering at HERA [1, 2]. The dynamical mechanisms for their production are not completely understood. They may be the result of hadronization of the proton remnant, leaving a baryon in the final state. Exchange of virtual particles is also expected to contribute. In this picture, the target proto...

A straightforward heteronuclear pseudo-3D NOESY-HSQC pulse sequence using radiation damping to selectively invert magnetization at the water frequency was developed to estimate the amide proton exchange rates in 15N-labelled proteins. The peak intensities in the resultant 2D spectrum allow a direct classification of amide proton exchange rates according to short (ms), intermediate (ms to s) or ...

An anisotropic model for the fabrication of annealed and reverse proton exchange waveguides in lithium niobate is presented. We characterized the anisotropic diffusion properties of proton exchange, annealing and reverse proton exchange in Z-cut and X-cut substrates using planar waveguides. Using this model we fabricated high quality channel waveguides with propagation losses as low as 0.086 dB...

η meson production in both proton-proton and proton-neutron collisions is investigated within a relativistic meson exchange model of hadronic interactions. It is found that the available cross section data can be described equally well by either the vector or pseudoscalar meson exchange mechanism for exciting the S 11 (1535) resonance. It is shown that the analyzing power data can potentially b...

Proton exchange membrane fuel cells are promising energy sources that produce electrical currents with almost null pollutant emissions, and they have been received growing attention in recent years. Maintaining a fuel cell system in correct operating conditions requires good system control. Based on the mathematical model of proton exchange membrane fuel cells, model linearization is carried ou...

The basolateral Na-H antiporter of the turtle colon exhibits both conductive and electroneutral Na+ transport (Post and Dawson. 1992. American Journal of Physiology. 262:C1089-C1094). To explore the mechanism of antiporter-mediated current flow, we compared the conditions necessary to evoke conduction and exchange, and determined the kinetics of activation for both processes. Outward (cell to e...

Proton exchange membranes for fuel cells were synthesized from the blend of copolymers of vinyl acetate-acrylic ester and styrene-acrylic ester, which were modified by sulfonation and addition of silica gel. Water uptake, ion exchange capacity, infrared spectroscopy and tensile tests were applied to characterize the prepared membranes. The results show that the prepared membranes with the proce...

output characteristics of fuel cells are affected by a large number of parameters such as geometry, dimensions, construction materials and conditions of supplying fluids. in this paper a mathematical model followed by a two-dimensional numerical approach has been presented to study the fuel cell parametrically. effect of oxygen concentration at gas diffusion layer entrance, temperature and pres...