Introduction to session 5 biotechnology,bioengineering, and the solution of environmental problems

Applied Biochemistry and Biotechnology -     

Methyl group replacement on pentamethylantimony with organophosphorus substituents

Phosphinic and phosphonic acids were treated with pentamethylantimony to replace one of its methyl groups (with formation of methane) to give the following new compounds: (CH₃SbOP(O)(C₆H₅)₂, (CH₃)₄SbOP(O)(OH)CH₃, and (CH₃)₄SbOP(O)(OH)C₆H₅). The latter two compounds are associated, presumably through hydrogen bonding.     

Coherence properties of individual femtosecond pulses of an x-ray free-electron laser

Measurements of the spatial and temporal coherence of single, femtosecond x-ray pulses generated by the first hard x-ray free-electron laser, the Linac Coherent Light Source, are presented. Single-shot measurements were performed at 780?eV x-ray photon energy using apertures containing double pinholes in "diffract-and-destroy" mode. We determined a coherence length of 17 μm in the vertical direction, which is approximately the size of the focused Linac Coherent Light Source beam in the same direction. The analysis of the diffraction patterns produced by the pinholes with the largest separation yields an estimate of the temporal coherence time of 0.55?fs. We find that the total degree of transverse coherence is 56% and that the x-ray pulses are adequately described by two transverse coherent modes in each direction. This leads us to the conclusion that 78% of the total power is contained in the dominant mode.