Thermally Activated Delayed Fluorescence in a Y3N@C80 Endohedral Fullerene: Time‐Resolved Luminescence and EPR Studies

The endohedral fullerene Y₃N@C₈₀ exhibits luminescence with reasonable quantum yield and extraordinary long lifetime. By variable‐temperature steady‐state and time‐resolved luminescence spectroscopy, it is demonstrated that above 60 K the Y₃N@C₈₀ exhibits thermally activated delayed fluorescence with maximum emission at 120 K and a negligible prompt fluorescence. Below 60 K, a phosphorescence with a lifetime of 192±1 ms is observed. Spin distribution and dynamics in the triplet excited state is investigated with X‐ and W‐band EPR and ENDOR spectroscopies and DFT computations. Finally, electroluminescence of the Y₃N@C₈₀/PFO film is demonstrated opening the possibility for red‐emitting fullerene‐based organic light‐emitting diodes (OLEDs).     

Projective and hereditary modules over rings of generalized matrices

This work is devoted to the investigation of projective modules over generalized matrix rings.     

On a representation of fully nonlinear elliptic operators in terms of pure second order derivatives and its applications

We give a method of representing fully nonlinear elliptic operators given by boundedly inhomogeneous functions in terms of operators acting only on pure second order derivatives. We also discuss possible applications of such representations to using .finite di.erence approximations for solving the corresponding equations.     

Structural transformations of supercooled water in nanopores, studied by microwave radiation

It is shown that the state of supercooled water in nanoporous materials can be studied by measuring the attenuation of microwave radiation. By analyzing variations in the intensity of radiation transmitted through a moistened medium during the supercooling of water in the range of ?37 to ?190°C, the temperatures at which structural transformations take place can be determined. Using the example of KSKG silica gel with a mean pore size of 8 nm, it is shown that at a moisture of 3?C18%, water is found in the liquid state up to a temperature of ?130°C, at which the transition to glass occurs.     

Quantum neural networks: Current status and prospects for development

The idea of quantum artificial neural networks, first formulated in [34], unites the artificial neural network concept with the quantum computation paradigm. Quantum artificial neural networks were first systematically considered in the PhD thesis by T. Menneer (1998). Based on the works of Menneer and Narayanan [42, 43], Kouda, Matsui, and Nishimura [35, 36], Altaisky [2, 68], Zhou [67], and others, quantum-inspired learning algorithms for neural networks were developed, and are now used in various training programs and computer games [29, 30]. The first practically realizable scaled hardware-implemented model of the quantum artificial neural network is obtained by D-Wave Systems, Inc. [33]. It is a quantum Hopfield network implemented on the basis of superconducting quantum interference devices (SQUIDs). In this work we analyze possibilities and underlying principles of an alternative way to implement quantum neural networks on the basis of quantum dots. A possibility of using quantum neural network algorithms in automated control systems, associative memory devices, and in modeling biological and social networks is examined.     

Quantum-Chemical Study of the Equilibrium Geometry and Electronic Structure of the Defensin Molecule

The molecular geometry of rabbit NP-1 defensin is fully optimized by means of molecular mechanics and MNDO methods. Atomic charges are calculated, and an estimate for the dipole moment of the molecule is obtained ( 4.0 D). The possible mechanism of defensin-receptor interactions is discussed.     

Lattice dynamics and hydrostatic-pressure-induced phase transitions in ScF3

New phase transitions induced by hydrostatic pressure in a cubic (under standard conditions) ScF₃ crystal are discovered by the methods of polarization microscopy and Raman scattering. The space groups $R\bar 3c$ for Z=2 and Pnma for Z=4 are proposed for the high-pressure phases. A nonempirical computation of the lattice dynamics of the crystal is carried out. It is shown that, under normal pressure, the cubic phase is stable down to T=0 K, while the application of a hydrostatic pressure gives rise to a phonon branch in the vibrational spectrum (between points R and M of the Brillouin zone) with negative values of squares of frequencies. The condensation of soft mode R₅ at the boundary point of the Brillouin zone leads to rhombohedral distortion of the cubic structure with the unit cell volume doubling. The calculated frequencies at q=0 of the ScF₃ lattice in the distorted rhombohedral phase are real-valued; the number and position of frequencies active in Raman scattering are in accord with the experimental values.     

Laser-ultramicroscopic method of determining suspended particles in high-purity liquids

Two main types of impurities in high-purity liquids have been determined. One consists of suspended particles of sub-mum size, and optical counters are the most suitable for their determination. Their main characteristics are given. The errors of suspended particle determination are discussed. The data on particles dispersion composition and concentration in some high purity liquids as well as on their nature are given.