CALCULATION OF THE INFLUENCE OF SHUNT PARAMETERS ON THE DV/DT EFFECT IN POWER PHOTOTHYRISTORS
The influence of the topological parameters of shunts in the cathode regions of a photothyristor on the dV/dt effect is calculated. The analytical condition that makes it possible to determine, in the first approximation, the region of the onset of the structure triggering caused by the dV/dt effect is obtained. When the forward voltage increases on the thyristor structure in the off state, the bias current flowing through the barrier capacitance of the inversely biased p-base-n-base junction causes a spontaneous triggering of the structure. This is the core of the dV/dt effect in thyristors
The calculation of the influence of the topological parameters of shunts in the cathode regions of the photothyristor on the dV/dt effect has been presented. The analytical condition, permitting in first approximation to determine in which region the structure switching will start due to dV/dt effect, has been obtained. This condition can be used in designing the photothyristors with the built-in protection against destruction during the uncontrolled turn on of the dV/dt effect. The high-voltage photothyristors in serial connection are applied, in particular, in the high-voltage direct current transmission lines. One of the main requirements for these devices is the availability of protection against overvoltage and dV/dt effect.
The effect of hydrogen-related shallow thermal donors and acceptor-like defects arising under proton irradiation of silicon on the breakdown voltage of a high-voltage p–n junction is considered. The relations making it possible to compute the breakdown voltage of the irradiated p–n junction taking into account the increase in critical field intensity during the ingress of hydrogen-related shallow thermal donors into the region of collisional ionization of the p–n junction are obtained. A technique for determination of the layer position and the minimum dose of hydrogen-related shallow thermal donors making it possible to decrease the breakdown voltage by a specified amount is proposed.
Generalized error-locating codes are discussed. An algorithm for calculation of the upper bound of the probability of erroneous decoding for known code parameters and the input error probability is given. Based on this algorithm, an algorithm for selection of the code parameters for a specified design and input and output error probabilities is constructed. The lower bound of the probability of erroneous decoding is given. Examples of the dependence of the probability of erroneous decoding on the input error probability are given and the behavior of the obtained curves is explained.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.
Let G be a semisimple algebraic group whose decomposition into the product of simple components does not contain simple groups of type A, and P⊆G be a parabolic subgroup. Extending the results of Popov , we enumerate all triples (G, P, n) such that (a) there exists an open G-orbit on the multiple flag variety G/P × G/P × . . . × G/P (n factors), (b) the number of G-orbits on the multiple flag variety is finite.
I give the explicit formula for the (set-theoretical) system of Resultants of m+1 homogeneous polynomials in n+1 variables