Quantum-mechanical theory of tunneling transport through open nanostructures based on nitride semiconductors, taking into account the contribution of acoustic phonons, is proposed. A variational ...method taking into account the component of Hamiltonian due to the deformation potential of acoustic phonons at different temperatures is developed. On the basis of the developed theory the transmission coefficient of a two-barrier AlN/GaN resonant tunneling nanostructure, its electronic conductivity and tunneling current are calculated taking into account the impact of acoustic phonons. It was found that with the increase of temperature values the frequencies of quantum transitions between electronic quasistationary states increase, an increase in temperature from cryogenic to room values results in a shift of the tunneling current peak and a decrease in the maximum value of dynamic conductivity in almost seven times.
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•Variational method for the Schrödinger equation in opened nanostructures.•Quasi-stationary states of electrons together with a subsystem of acoustic phonons.•Electronic tunneling transport taking into account the impact of acoustic phonons.
The non-isothermal adsorption/desorption of gas in a cylindrical column filled with adsorbent particles has been considered theoretically. The model is based on Langmuir theory for equilibrium ...adsorption. Using the Heaviside operational method the analytical solutions for kinetics of changes of concentration of adsorbate in the inter- and intra-particle spaces were obtained. The numerical calculations of gas adsorption at different temperature of the gas flow (
T
a
= 273–373 K) followed by desorption by the flow of inert gas through the column at
T
d
= 673 K were done. The results revealed the rather complex interrelations between spatial–temporal dependencies in distribution of concentrations of adsorbed gas inside adsorption column and temperatures of inlet gas.
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Using the effective mass model for an electron and the dielectric continuum model, analytical solutions of the self-consistent Schrödinger-Poisson system of equations are obtained. Quantum mechanical ...theory of electronic stationary states, the oscillator strengths of quantum transitions and a method of potential profile calculation is developed for the experimentally constructed three-well resonance-tunneling structure — a separate cascade of quantum cascade detector. For the proposed method, a comparison with the results of other methods and with the results of the experiment was carried out. A good agreement between the calculated value of the detected energy and its experimental value has been obtained, the difference being no more than 2.5%.
To date, Higgs boson production has been observed at the Large Hadron Collider (LHC) in four different channels. Associated Higgs boson production with a single top quark has not yet been observed. ...Study of this channel would make it possible to determine, for the first time, the complex phase of top-quark coupling to the Higgs boson. The possibility of discovering associated Higgs boson production with a single top quark is studied here by means of a Monte Carlo simulation. Criteria for signal selection and for the suppression of background events are proposed. It is shown that the set of data currently available from the LHC permits confirming or excluding a model in which the top-quark coupling to the Higgs boson has a sign opposite to that predicted by the Standard Model.
The theory of the interaction of electrons with acoustic phonons in multilayer nitride-based AlN/GaN nanostructures was developed for the first time at T ≥ 0 using the method of finite-temperature ...Green's functions and Dyson equation. Components of the Hamiltonian describing the system of electrons with acoustic phonons and the magnitudes of the electron spectrum shifts due to the electron-phonon interaction were obtained. Dependences of the electronic spectrum levels and spectrum of the acoustic phonons were found depending on the position of the internal potential barrier in the studied nanostructure. The temperature shifts of the electronic spectrum and decay rates were calculated for various values of temperature T.
The interaction of the Higgs boson with the heaviest particles of the standard model: the top quark, seems promising in the search for new physics beyond the standard model. This interaction is ...determined by the Yukawa interaction constant. Its complex phase is still unknown, but can be determined by studying the production of the Higgs boson together with a single top quark. This channel has not been observed yet. In this paper, we consider the possibility of increasing the significance of the Higgs boson production in association with a single top quark using Monte-Carlo simulation of signal and background processes.
Specific inhibitors of mitochondrial 2-oxoglutarate dehydrogenase (OGDH) are administered to animals to model the downregulation of the enzyme as observed in neurodegenerative diseases. Comparison of ...the effects of succinyl phosphonate (SP, 0.02 mmol/kg) and its uncharged precursor, triethyl succinyl phosphonate (TESP, 0.02 and 0.1 mmol/kg) reveals a biphasic response of the rat brain metabolism and physiology to increasing perturbation of OGDH function. At the low (TE)SP dose, glutamate, NAD
, and the activities of dehydrogenases of 2-oxoglutarate and malate increase, followed by their decreases at the high TESP dose. The complementary changes, i.e., an initial decrease followed by growth, are demonstrated by activities of pyruvate dehydrogenase and glutamine synthetase, and levels of oxidized glutathione and citrulline. While most of these indicators return to control levels at the high TESP dose, OGDH activity decreases and oxidized glutathione increases, compared to their control values. The first phase of metabolic perturbations does not cause significant physiological changes, but in the second phase, the ECG parameters and behavior reveal decreased adaptability and increased anxiety. Thus, lower levels of OGDH inhibition are compensated by the rearranged metabolic network, while the increased levels induce a metabolic switch to a lower redox state of the brain, associated with elevated stress of the animals.
High-performance supercomputer computing technologies have been developed to model and identify the parameters of complex n-component competitive adsorption processes in nanoporous cybersystems with ...feedback. Using the Laplace transform and the Heaviside operating method with the decomposition of a nonlinear system with Langmuir-type adsorption equilibrium conditions, an efficient parallelization of the vector components of the model solution is proposed. The results of numerical experiments based on parallel computations using multicore computers are presented.
New high-performance analytical methods are developed for modeling the concentration fields of diffused gases in intra- and interparticle spaces in heterogeneous cylindrical
n
-component nanoporous ...media. The methods use the Heaviside operational method and Cauchy influence matrices for inhomogeneous adsorption boundary-value problems for systems of partial differential equations with feedbacks.
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