The Time-Resolved Fluorescence Stokes Shift of Cucurbit[6]Uril Complexes with a Pyridinium Styryl Dye

The time-resolved Stokes shift of fluorescence of styryl dye, trans-4-[4-(dimethylamino)-styryl]-1-methylpyridinium iodide (DASPI), and its host-guest complexes with cucurbit[6]uril (CB[6]) was studied by up-conversion technique on a 5 ps time scale. In all cases, the solvation time correlation function – that describes relaxation of the fluorescent state - contains two components. The time constant of the first component, which is related to the vibrational relaxation of the dye cation, increases from 118 fs without CB[6] to 224 fs in the presence CB[6]. It suggests the production of CB[6] complexes to disturb the hydrogen-bond net in the vicinity of DASPI cation. The time constant of the second component, which is associated with solvation, changes from 0.81 ps without CB[6] to 1.15 ps in the presence of the cavitand. The observed increase can be related to the displacement of the dye cation deeper into CB[6] that allows considering DASPI-CB[6] complexes as a light-controlled molecular machine with a response time on the picosecond scale.     

Mobility of small molecules in membrane materials based on copolyimide P84

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Experimental determination of the fracture time of polymethylmethacrylate and polystyrene behind the shock wave excited by a high-current pulsed electron beam

The time ranges of the fracture of polymethylmethacrylate and polystyrene during the action of a shock wave generated by a high-current pulsed electron beam are experimentally determined using laser probing in combination with electron-optical chronography. It is shown that fractures occur during unloading of a material, i.e., after the passage of the shock wave. Although the characters of fracture of these polymers near the surface irradiated by electron beam are different, the fracture wave velocities in them are found to be close.     

Physicochemical Processes Accompanying the Plastic Strain Localization under Pulsed Loading

The formation of localized deformation bands is accompanied by the mass transfer of particles of the matrix material (interstitial atoms, impurities, etc.) toward faults in the material being destroyed and by the emergence of stress oscillations in a mode of ultrasonic vibrations lasting several orders of magnitude longer than the initial pulse. It was assumed that dislocations generated under pulsed deformation are the cause of the migration of particles.     

The comparison of binary- and ternary-fission configurations close to the instant of scission

A new way to bring into comparison the binary- and ternary-fission configurations is proposed. The method is founded on recently discovered ROT effect. The angle of fission axis deflection from its initial orientation at the moment of scission comes into existence as a result of dividing system rotation and carries information about fissioning nucleus deformation. The comparison of proper angles for binary and ternary fission can be used to estimate the difference in the rupture configurations.     

Conductivity of Composite Films Based on Conductive Polymer PEDOT:PSS,Graphene Oxide and Nanoparticles TiO2 for Contact Layers of Perovskite Photovoltaic Structures

Physics of the Solid State - The electrical properties of composite films based on conductive polymer PEDOT: PSS, graphene oxide (GO), and titanium dioxide nanoparticles (TiO2) (PEDOT: PSS–...     

Viscous fluid velocity field between two cylinders which rotate and move translationally

Viscous fluid flow in the domain between circular cylinders is considered. The fluid flow is initiated by rotational and translational motions of the cylinders. A general analytic expression for the fluid velocity field is constructed using the conformal mapping method and the bipolar coordinates. The streamline structure is studied for the steady-state flows.     

Alkali metal polyphosphides as intermediates in the synthesis of organophosphorus compounds from elemental phosphorus

Russian Chemical Bulletin - Methods for the preparation of alkali metal polyphosphides, as well as their reactivity with respect to organic substrates, namely, electrophilic reagents and...