ANALYSIS OF ACCURACY OF SPATIAL SYNCHRONIZATION OF TEMPORAL POSITION OF SIGNALS OF PULSED PHASED ANTENNA ARRAY OF SUBNANOSECOND RANGE IN PRESENCE OF RANDOM CHANNEL DELAYS

The structure of the pulsed phased antenna array (PPAA) of the sub nanosecond range with the system of automatic synchronization of the temporal position of the emitted ultra short pulses is presented. The analysis of the causes and the quantitative estimation of the instrumental error of the PPAA channels has been carried out. The partial contribution to the instrumental error of the channel functional nodes is estimated. Mathematical modeling has been carried out in order to assess the effect of channel delay spread on the total intensity of the emitted signal for the Gaussian and normal laws of their distribution. An acceptable range of variation of channel delay values is determined, correlated to the duration of the pulses emitted by the antenna modules, with an acceptable reduction in the quality of their spatial synchronization. The locations of possible localization in the PPAA structure of temporal modulators intended for the initial alignment of channels and electronic scanning by the beam of the radiation pattern are indicated. The requirements for the parameters of splitter modulators are formulated. The simulation results are confirmed by experimental studies.

Influence of alkyl substituents in corrphycene on geometry, electronic structure, hydrogen bonding, and tautomerization

Geometry, electronic and vibrational structure, and relative energies of different tautomeric forms have been calculated for free base corrphycene and its five tetra-, octa-, and dodeca-alkyl-substituted derivatives, of which only one has been synthesized so far. The results demonstrate that the lowest energy structure always corresponds to the transtautomeric form. Comparison with the experimental IR and X-ray data available for 2,3,6,7,11,12,17,18-octaethylcorrphycene shows, in contrast to previous suggestions, that th. transspecies is dominant both in solution and crystalline phase. Based on structural, spectral, and computational data, rates of double hydrogen transfer can be predicted. Tautomerization is expected to occur in a nanosecond or subnanosecond range. The rate should strongly decrease upon substituting parent corrphycene with alkyl groups at the pyrrolic [Formula: see text] positions, whereas the opposite effect is expected for mesosubstitution. Depending on the position of substituent, planar or nonplanar geometries of the corrphycene chromophore are predicted. The nonplanarity leads to a substantial increase of the intensity of the low energy electronic transitions (Q-bands).