Vol 58, No 9 (2016)

Spectroscopic characteristics of complexes of Cu[I] ion with halogens synthesized by the TDDFT/CAM-B3LYP method are studied. It is shown that S0 → S1 and S0 → T1 electronic transitions are excitations with charge transfer. In this case, the electronic transitions proceed from the HOMO, HOMO-1 and HOMO-2 localized on halogen atoms to the LUMO localized on a ligand. The matrix elements of spin-orbit interaction are calculated using the single-electron operator (HSO). Based on these compounds, the organic light emitting diodes have been created. Their current–voltage and current-brightness characteristics are investigated.

The H₂¹⁶O vapor absorption line broadening by nitrogen pressure is investigated in the range of 12411–12421 cm⁻¹using a laser optoacoustic spectrometer with a Ti: sapphire laser having a lasing line width of 50 kHz. The broadening coefficients of 7 H₂O lines determined by transitions to levels with the vibrational quantum numbers v = 4–8 are measured with an absorption sensitivity threshold of 10⁻⁸cm⁻¹. Experimental line half-widths are compared with their values calculated by the semi-empirical method.

A temperature dependence of the magnetic susceptibility [χ(T)] of rare-earth borates RAl₃(BO₃)₄ (R = Tb, Er, or Ho) is measured by the Faraday method at temperatures in the interval 20–850°С. Nonlinear anomalies caused by structural transitions are observed in the dependences χ^–1(T). It is established that the dependences χ^–1(T) for each phase obey the linear Curie–Weiss law. The Curie temperatures and the magnetic moments corresponding to the chemical formula of the compounds have been found.

A phase shift analysis has been carried out on the basis of known experimental measurements of the excitation functions of elastic p¹⁴C scattering at four angles from 90° to 165° and more than 100 energy values from 600–800 to 2200–2400 keV to determine the position of the ²S_1/2 resonance at 1.5 MeV. The obtained shape of the resonant ²S_1/2 phase shift agrees overall with the characteristics of the corresponding level of the 15N nucleus, and the proposed potential acceptably describes this scattering phase shift.

Normal electromagnetic waves (Beltrami wave fields) in a metachiral medium with constitutive equations in the Post form are investigated. The chirality parameter, and the permittivity and permeability are arbitrary real quantities. Expressions for the wave numbers and wave impedance of propagating, and also evanescent, plane waves are derived. Three regimes of the existence of a pair of forward and backward waves are identified.

Results of measurement of dielectric properties of birch wood in the radio-frequency range depending on its humidity are presented. The dependences obtained indicate strong influence of wood anisotropy especially at low frequencies. It is shown that it is irrational to use the wood for insulation if its humidity exceeds 15–20%.

The temperature dependences of linear and nonlinear dielectric properties of potassium nitrate (KNO₃) and crystalline binary mixtures (KNO₃)_1–x(NH₄NO₃)_x (x = 0.025, 0.035, 0.05, 0.1) in the temperature interval 300–460 K have been investigated. An influence of the NH4NO3 impurity on the existence interval of the ferroelectric phase with increase of the impurity content has been detected. For x = 0.05 the ferroelectric phase is maintained down to room temperature.

Ceramic-metal materials (cermets) based on titanium diboride and boron carbide are designed and produced by the method of self-propagating high-temperature synthesis, with the pressure applied to the combustion products. The data, obtained by an experimental-theoretical investigation of impact resistance of protective barriers containing the above-mentioned materials in collisions with a spherical steel projectile, are presented. A better impact resistance of TiB₂ + B₄C cermets compared to that of Al₂O₃-ceramics is demonstrated. A possibility of prediction calculations of impact resistance of the specimens containing cermets in the range of collision rates under study is shown.

The results obtained from investigations into the special features inherent in the mechanical characteristics (Hugoniot elastic limit and spall strength) observed under shock-wave loading of Al–Al₂O₃composite samples produced by an explosive powder compaction technique are presented. Embedding 10 wt.% of aluminum oxide in the aluminum matrix has been found to increase the Hugoniot elastic limit as opposed to the commercialgrade AD1(Al 1013) aluminum alloy.

A new method of increasing resolution of radio images due to nonlinear ultra-wideband data processing without any modification of the employed hardware is presented. The approach is applicable for stroboscopic filling of ultrashort impulses in which the error of triggering of a sensing impulse generator – a jitter – detected as noise in the gated data – is always presented. The nonlinear operation of selection of the coherent noise component in combination with the synthetic aperture radar (SAR) method provides a higher contrast of the radio image in comparison with operation of jitter smoothing. As a result, the physical effect of jitter occurrence that is typically negative yields a positive result. Examples of experimental data processing confirm this conclusion.

Bound states of a relativistic two-particle system with arbitrary orbital angular momentum are considered. Three-dimensional integral equations are reduced to partial integral equations and differential equations. Analytical and numerical solutions are presented. The dependences of the spectra of the coupling constant and of the wave functions on various parameters are investigated.

The possibility of lasing on self-terminating transitions in a low-current discharge mode is shown in model and real experiments on an example of a copper vapor laser. Lasing is excited in a discharge gap self-breakdown mode for a wide range of pumping pulse repetition frequencies (from several Hz to 10 kHz). The low-current discharge mode is characterized by pulse current of several amperes, voltage falling edge after the breakdown of 10–15 V/ns, and current rising rate less than 0.01 A/ns, which distinguishes this type of pumping from conventional one used for lasers on self-terminating transitions.

Fractional derivative formalism is proposed as the mathematical foundation of the polarization-depolarization current method for the diagnosis of dielectric isolation. Physical basis of the new approach is the observed deviation of the long-term relaxation from the Debye exponential law. We found that this behavior is consistent with the solution of the fractional differential equation: exponential behavior turns into the power dependence in the long-time asymptotics, and this part of the relaxation curve is more sensitive to the material state. The results of calculations for the polarization-depolarization currents in an oil-paper capacitor are in agreement with the specially performed experiments.

Special features of sputtering of the cathode with a thin dielectric film of variable thickness in a glow discharge are studied. It is shown that the flux density of atoms sputtered from the cathode is maximal on its sections with minimal film thickness due to focusing of ion flux caused by the violation of the electric field uniformity near the cathode surface. As a result, the non-uniformity of the film thickness increases with time, thereby leading to the formation of pores in the film.

Functional reliability is one of the important properties of physical systems provided by reliability of system components, in particular, control logical components. The new approach to fully delay testable circuit design oriented to cut overheads and lengths of circuit paths has been developed. Compact representation of all PDF test pairs is reduced to keeping the corresponding generative vector pairs. The number of generative vector pairs does not exceed the doubled number of internal ROBDD nodes originating from the circuit, while the number of the circuit paths can exponentially depend on the number of these internal nodes. The algorithm of involving the PDF test pair from the proper generative vector pair is suggested. This procedure does not require essential calculations. The algorithm of deriving the generative vector pair has a polynomial complexity.

Morphological and fractographic features of change of FeCo-based amorphous alloy surfaces after laser treatment are studied in detail. Regimes of laser treatment that allow various degrees of crystallization of the examined alloys to be obtained, including thin (<1 ∙m) crystal layers on amorphous alloy surfaces, amorphous-crystalline composites, and completely crystalline alloys are adjusted. The Vickers hardness is estimated in zones of selective laser irradiation. The structure of the examined alloys attendant to the change of their mechanical properties is analyzed.