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Mesoporous multiphase amorphous–crystalline Bi2O3 nanopowder with the specific surface area of 23 m2/g is obtained using pulsed electron beam evaporation in vacuum. The influence of thermal annealing (200–300°C) of the powder in air has been investigated. Droplets 2–5 nm in size are formed on the surface of all large nanoparticles comprising the framework of 3D agglomerates of the nanopowder due to extrusion of liquid bismuth from bulk upon cooling. [ABSTRACT FROM AUTHOR]

The crystallophores of the composition Sr2La8(1x-y)ErxYbyGe6O26 (x = 0.01, 0.05, 0.075, 0.1, 0.15) were synthesized. Nanophosphores in the amorphous state were obtained for the first time by the method of pulsed electron beam evaporation using a phosphor of the composition Sr2La7.85Er0.075Yb0.075Ge6O26 with the structure of oxyapatites as a target. DSC-TGA analysis was performed to determine the temperature stability and the onset of crystallization of the nanosample. A change in the Raman spectra of the samples with a decrease in the particle dimension from the bulk to nanoscale state was found. The spectral characteristics of the upconversion photoluminescence of samples in polycrystalline and nano-amorphous states are studied. It has been shown that luminescence is influenced by nonradiative processes between different transitions of Er3+ ions. There is a threshold population of the Er3+ and Yb3+ levels (level 2F5/2) in the region of relatively low pumping powers of nanosamples by laser radiation with a wavelength of λex = 980 nm. Above this threshold a sharp increase in the intensity of upconversion photoluminescence occurs. [ABSTRACT FROM AUTHOR]

Using vacuum evaporation by a pulsed electron beam, mesoporous CaF2 nanopowders with a specific surface area of up to 91.5 m2/g were obtained. The effect of nanosecond electron beam irradiation in air on the magnetic and texture properties of the obtained nanopowders was studied. For the first time, the effect of irradiation on the specific surface and magnetization of CaF2 nanopowders was revealed. [ABSTRACT FROM AUTHOR]

An analysis of competitiveness of thyratrons in relation to up-to-date solid-state devices has been carried out. The design features and parameters of a number of new TGI thyratrons with a hot combined impregnated cathode for operating voltages of 30, 50, and 75 kV, average switching power from 150 to 500 kW and pulsed power to 250 MW, are presented. Thyratrons have a tetrode design with air cooling in the metal ceramic version. The main field of application is high-power electrophysical equipment. In particular, we present the examples of using thyratrons in accelerators as modulators, as well as pulse corona power supplies for air purification systems from hydrogen sulfide, ammonia, and other harmful gases in the streamer corona discharge. [ABSTRACT FROM AUTHOR]

Mesoporous amorphous-crystalline nanopowders of BaF2 with the specific surface area up to 34.8 m2/g were obtained using evaporation by a pulsed electron beam in vacuum. Influence of the thermal annealing of the BaF2 nanoparticles in air at the temperatures from 200 to 900°C on the size and morphology of the particles and changes in their magnetic and luminescent properties was studied. The paramagnetic response of the BaF2 nanopowder was found to transform to the ferromagnetic response after annealing at 900°C. The appearance and transformation of the magnetic response in nanopowders made of BaF2, which is diamagnetic as the bulk material, are ascribed to the appearance of radiation-induced and structural defects during the synthesis process by pulsed electron-beam evaporation. [ABSTRACT FROM AUTHOR]

Methods for the synthesis of new chelating chitosan derivatives containing 2-carboxyethyl groups were developed. Their macromolecules were cross-linked by the irradiation with a nanosecond electron beam, which gave for the first time sorbents with a high sorption capacity for CuII ions. The maximum sorption capacity, which is achieved in the pH range 6.5–7.2. and the Langmuir adsorption constant of Cu2+ ions on the sorbent with the degree of substitution 0.91 are 1.37 mmol g−1 and 152.51 L mol−1, respectively. The structures of the formed complexes in the sorbent phase were characterized by ESR spectroscopy. [ABSTRACT FROM AUTHOR]

A vacuum diode for the two-sided electron irradiation of objects makes it possible to reduce the irradiation nonuniformity and increase the thickness of the irradiated layer of the object with a uniform distribution of the absorbed dose over the layer thickness. The cathode holder of the diode is constructed in the form of two symmetrical arms connected to a common current lead. Two cathodes are attached to the arms' ends opposite each other. The electron beam is extracted to the atmosphere through two windows–anodes positioned across from one another. The vacuum diode with metal–dielectric cathodes was tested on a УРТ-0.5 nanosecond electron accelerator (the electron energy is ∼0.5 MeV and the output beam power is ∼1 kW). The results obtained have shown that the diode ensures the two-sided irradiation of objects. Depending on the irradiated surface, the irradiation conditions can be varied by changing the cathode–anode distance in one of the arms of the diode. [ABSTRACT FROM AUTHOR]

The characteristics of a metal-ceramic (MC) cathode designed for nanosecond electron accelerators are studied in relation to the size of metal particles, their density on the ceramic surface, and the type of ceramics. A high emissivity of the MC cathode at a moderate electric field in the diode tube is demonstrated. This allows one to significantly sharpen the electron beam and increase its current (power). The possibility of controlling the emissivity of the MC cathode by varying the composition of the MC plate is established. © 2003 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]

Investigates the emissive characteristics of metal-ceramic cathodes for electron accelerators. Experimental procedure; Principal experimental results; Estimate of the electric-field intensity near the metallic particles embedded into the dielectrics.

The magnetic properties of oxide nanopowders obtained by pulsed electron beam evaporation of targets in a low-pressure gas phase have been studied. Using this method, we obtained Zn-ZnO and ZnO nanopowders with the specific magnetization amounting to 2.8 × 10−2 and 2 G cm3/g, respectively. Significant room-temperature ferromagnetism has been observed for the fist time in a nanopowder of yttria-stabilized zirconia, where the specific magnetization reached ∼6.7 × 10−2 G cm3/g. [ABSTRACT FROM AUTHOR]

An investigation was made of the radiation resistance of the internal memory of programmable logic devices. It was established that the internal memory of CMOS devices shows enhanced sensitivity to ionizing radiation when their outputs are shorted together. Information stored in the internal memory of the devices is erased at an absorbed dose substantially below the level at which the device fails. It is suggested that this effect may be used as a method of erasing information. [ABSTRACT FROM AUTHOR]