Clipper circuit of pulse modulator used for Klystron-5045 power supply

While the operation of modulator to the pulsed transformer of klystron-5045, current through the primary winding of the pulse transformer (PT) continues to flow even upon the end of the klystron voltage operating pulse. This is determined by an energy stored in magnetizing inductance. The prolongation of magnetizing current passing process simultaneously with the premature choking of thyratron can cause high voltage of inverse polarity at the klystron, which cause the destruction of the cathode. We have considered the possibility of shortening time of magnetizing current passage for the charge of reasonable choice of clipper circuit parameters. The behavior of clipper circuit was studied in modulators used for the VEPP-5 (BINP, Russia) preinjector klystron power supply. The optimum operation run of the circuit was selected and its design features are described

Effect of a Stable Magnetic Field on Silicon Properties

The effect of a constant magnetic field (0.17 T) on microhardness, kinetics of photoconductivity decline and electro conductivity in silicon crystals is studied. The nature of changes of micromechanical and electrophysical characteristics in samples is investigated as a function of time elapsed after magnetic treatment. The results obtained are discussed in terms of magnetic field stimulated processes occurring in a subsystem of structural defects

Effect of a Stable Magnetic Field on Silicon Properties

The effect of a constant magnetic field (0.17 T) on microhardness, kinetics of photoconductivity decline and electro conductivity in silicon crystals is studied. The nature of changes of micromechanical and electrophysical characteristics in samples is investigated as a function of time elapsed after magnetic treatment. The results obtained are discussed in terms of magnetic field stimulated processes occurring in a subsystem of structural defects

Forming of Nanoscale Structure in Manganite Ceramics with Superstoichiometric Manganese

The new method for obtaining of the nanoscale structure by means of superstoichiometric manganese in lanthanum manganite (La0.65Sr0.35)1 – xMn1 + xO3 +_ Δ (x = 0, 0.1, 0.2) ceramics sintered at 1500 °C is developed. The increasing of x content from 0.1 to 0.2 leads to forming internal nanosize multilayer structure of ceramic grains with layer size of 190 and 280 nm, respectively. The correlation between such nanostructure and magnetoresistive properties is revealed. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3533

The usage of the method of mathematical statistics in the process of optimization of the content of antifriction composite materials

The optimum content of microtalc (dispersion d = 7...10 µm) and silver carbonate (dispersion d = 0,5 µm) fillers in polymeric materials was determined by the method of mathematical statistics to form an adhesive and functional layers of protective coatings. The mathematical models of physicomechanical and thermophysical characteristics of composites were obtained by the method of statistical processing of the results of the investigation materials

Dynamic Processes During the Through-plastic-damper Shock Interaction of Rocket Fairing Separation System Components

This article deals with the actual issues of ensuring the dynamic strength of rocketry components using pyrotechnics.Статтю присвячено актуальним питанням забезпечення динамічної міцності елементів ракетної техніки під час використання піротехнічних засобів.Статья посвящена актуальным вопросам обеспечения динамической прочности элементов ракетной техники при использовании пиротехнических средств

Picosecond acoustics in single quantum wells of cubic GaN/(Al,Ga)N

A picosecond acoustic pulse is used to study the photoelastic interaction in single zinc-blende GaN/AlxGa1−xN quantum wells. We use an optical time-resolved pump-probe setup and demonstrate that tuning the photon energy to the quantum well’s lowest electron-hole transition makes the experiment sensitive to the quantum well only. Because of the small width, its temporal and spatial resolution allows us to track the few-picosecond-long transit of the acoustic pulse. We further deploy a model to analyze the unknown photoelastic coupling strength of the quantum well for different photon energies and find good agreement with the experiments

A weakly coupled semiconductor superlattice as a harmonic hypersonic-electrical transducer

We study experimentally and theoretically the effects of high-frequency strain pulse trains on the charge transport in a weakly coupled semiconductor superlattice. In a frequency range of the order of 100 GHz such excitation may be considered as single harmonic hypersonic excitation. While travelling along the axis of the SL, the hypersonic acoustic wavepacket affects the electron tunnelling, and thus governs the electrical current through the device. We reveal how the change of current depends on the parameters of the hypersonic excitation and on the bias applied to the superlattice. We have found that the changes in the transport properties of the superlattices caused by the acoustic excitation can be largely explained using the current-voltage relation of the unperturbed system. Our experimental measurements show multiple peaks in the dependence of the transferred charge on the repetition rate of the strain pulses in the train. We demonstrate that these resonances can be understood in terms of the spectrum of the applied acoustic perturbation after taking into account the multiple reflections in the metal film serving as a generator of hypersonic excitation. Our findings suggest an application of the semiconductor superlattice as a hypersonic-electrical transducer, which can be used in various microwave devices

Magnon polaron formed by selectively coupled coherent magnon and phonon modes of a surface patterned ferromagnet

Strong coupling between two quanta of different excitations leads to the formation of a hybridized state which paves a way for exploiting new degrees of freedom to control phenomena with high efficiency and precision. A magnon polaron is the hybridized state of a phonon and a magnon, the elementary quanta of lattice vibrations and spin waves in a magnetically-ordered material. A magnon polaron can be formed at the intersection of the magnon and phonon dispersions, where their frequencies coincide. The observation of magnon polarons in the time domain has remained extremely challenging because the weak interaction of magnons and phonons and their short lifetimes jeopardize the strong coupling required for the formation of a hybridized state. Here, we overcome these limitations by spatial matching of magnons and phonons in a metallic ferromagnet with a nanoscale periodic surface pattern. The spatial overlap of the selected phonon and magnon modes formed in the periodic ferromagnetic structure results in a high coupling strength which, in combination with their long lifetimes allows us to find clear evidence of an optically excited magnon polaron. We show that the symmetries of the localized magnon and phonon states play a crucial role in the magnon polaron formation and its manifestation in the optically excited magnetic transients

Modulator power supply for 200 kV electron gun of the VEPP-5 injection complex

The 200 kV electron gun modulator power supply based on the half-bridge converter providing the high frequency partial charge of the capacitive energy storage element is described. The algorithm developed for the power supply driving allows one to provide the soft switching of charging circuits and to achieve a high efficiency of the power supply. The data obtained at operation of the capacitive loaded 300 W power supply are presented. The prospects of developing such type tens-kilowatts power supply are discussed.Описано пристрій високочастотного порціонного заряду ємнісного накопичувача енергії для живлення 200 кВ електронної гармати. Спеціально розроблений алгоритм керування дозволяє забезпечити м'яку комутацію ключів зарядних контурів, домогтися високого ККД зарядного пристрою. Приведено експериментальні дані, зняті при роботі зарядного пристрою на ємнісне навантаження потужністю 300 Вт. Обговорюються перспективи створення зарядних пристроїв такого типу потужністю десятки кіловат.Описано устройство высокочастотного порционного заряда емкостного накопителя энергии для питания 200 кВ электронной пушки. Специально разработанный алгоритм управления позволяет обеспечить мягкую коммутацию ключей зарядных контуров, добиться высокого КПД зарядного устройства. Приведены экспериментальные данные, снятые при работе зарядного устройства на емкостную нагрузку мощностью 300 Вт. Обсуждаются перспективы создания зарядных устройств такого типа мощностью десятки киловатт