Multiple functionalization of single-walled carbon nanotubes by dip coating

Single walled carbon nanotubes were functionalized with different functionalities by simple dip coating. This fast and reproducible procedure was realized with nanotube coated electrodes for the construction of polyvalent biosensors. Three different pyrene derivatives were attached to the nanotube sidewalls by π-stacking interactions in a one-step reaction.     

Nucleophilic and Electrophilic Additions to Silylated Ketenimines Generated from Imidothioesters.

The reactivity of stable silylated N-phenyl ketenimines towards some nucleophilic (organometallics, alcohols, thiols) and electrophilic reagents (PhSCI) were studied. Imino-coumarines (via tandem nucleophilic-electrophilic additions with Peterson olefination) and new phenylthio- and silyl-substituted ketenimines have been prepared.     

The exact distribution of indefinite quadratic forms in noncentral normal vectors

The exact density of the difference of two linear combinations of independent noncentral chi-square variables is obtained in terms of Whittaker's function and expressed in closed forms. Two distinct representations are required in order to cover all the possible cases. The corresponding expressions for the exact distribution function are also given.     

Tris‐Heteroleptic Ruthenium–Dipyrrinate Chromophores in a Dye‐Sensitized Solar Cell

Two novel tris‐heteroleptic Ru–dipyrrinates were prepared and tested as sensitizers in the dye‐sensitized solar cell (DSSC). Under AM 1.5 sunlight, DSSCs employing these dyes achieved power conversion efficiencies (PCEs) of 3.4 and 2.2 %, substantially exceeding the value achieved previously with a bis‐heteroleptic dye (0.75 %). As shown by electrochemical measurements and DFT calculations, the improved PCEs stem from the synthetically tuned electronic structure, which affords more negative excited state redox potentials and favorable electron injection into the TiO₂ conduction band. Electron injection was quantified by nanosecond transient absorption spectroscopy, which revealed that the highest injection yield is achieved with the dye that acts as the strongest photoreductant.     

On stretching of a bar capable of undergoing phase transitions

The dynamic processes in an elastic bar composed of a material, which is capable of undergoing phase transitions, are under consideration. We use a model of an elastic body with non-convex strain energy potential. The bar with variable cross-sectional area is considered. Propagation of the phase boundary along the bar loaded with time-dependent tensile forces is investigated. It is assumed that the phase boundary moves at a variable speed. The problem is solved analytically by using two approaches, namely, the full dynamic approach and the quasi-static (kinetic) approach. The results obtained by means of these two methods are compared.