All-binary InAs/GaAs optical waveguide phase modulator at 1.06μm

We demonstrate the use of multiple [(InAs) (GaAs)]/GaAs short-period strained-layer superlattice quantum wells for optical waveguide modulation at 1.06 μm. We achieve π phase modulation with 2.3 V applied (V_π×L=4.6 V mm, or 39°/V mm) in the presence of negligible absorption change using this all-binary modulator     

A method of calculation of accessibility to solvent of aromatic amino acid residues of proteins in water-organic mixtures]

Suggested method for calculation of solvent accessibility of tryptophan and tyrosine residues in water-organic mixtures is based on evaluation of second order derivatives of UV spectra. Second order derivative of the spectrum enable differentiation between direct effects of the organic solvent on spectral characteristics of exposed aromatic amino acid residues and the effect of the organic solvent on protein conformation. The method is suitable for calculation of exposition of tryptophan in water-organic mixtures if the content of tyrosine amino acid residues in protein does not exceed the content of tryptophan. Similar method of calculation of exposition of tyrosine residues can be used in proteins when the content of tyrosine is at least 5-fold higher than the content of tryptophan. For example, solvent accessibility of tryptophan residues of chymotrypsin is calculated in the presence of various organic solvents including ethanol, dioxane, and dimethyl formamide.     

Finite element calculation of photoacoustic signals

A procedure for the numerical calculation of photoacoustic signals is introduced. It is based on the finite element method and uses an expansion of the signal into acoustic eigenmodes of the measuring cell. Loss is included by the incorporation of quality factors. Surface and volume loss effects attributable to viscosity and thermal conductivity are considered. The method is verified for cylindrical cells with excellent accordance. The application to photoacoustic cells of unconventional shape yields good agreement with experimental data.