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Temperature X-ray, pyro- and dielectric measurements of Pb(Fe0.5Ta0.5)O3-single crystals have been carried out. It was concluded that Curie temperature (Tc ) of this compound is about 370 K, but not 243 K as it has been decided early. Well-known experimental data have been analyzed on ferro- (FE) and antiferroelectric (AFE) perovskites of simple and complex composition. It was concluded that in many cases Tc has to be connected with weakly manifested high temperature anomalies of structural parameters and of electrophysical properties, but not with strongly manifested anomalies observed often at lower temperatures.

The applicability of various linear electron accelerators for the acceleration of heavy pulsed currents is estimated. It is shown that linear standing-wave electron accelerators, which use the high-frequency power stored in resonant cavities, for the acceleration of particles offer greater possibilities in comparison with ordinary linear traveling-wave electron accelerators. The possibility of accelerating currents of the order of 100 amp in pulses with a duration of approximately 1 μ sec is demonstrated.

The suitability of various types of electron linear accelerator for the acceleration of large current pulses is examined. It is shown that standing wave electron linear accelerators in which the r.f. power stored in resonant cavities is used to accelerate the particles have greater potentialities as high current machines than the more conventional travelling wave accelerators. It is shown also that it is feasible to accelerate currents of the order of 100 A in pulses with a duration of about 1 μsec.

An electron linear accelerator capable of providing high pulsed currents of accelerated electrons is described. The accelerator consists of two coupled resonators excited at a frequency of 137.4 Mc/s by 12 auto-generators each delivering up to 100 kW of power in a 400 μsec pulse. Results obtained with this accelerator are in accordance with the theoretical calculations(1). An electron current of 8.5 A was obtained in a pulse of 0.2 μsec duration and at an energy of 4.5 MeV. The maximum charge of the accelerated electrons per pulse was 3 × 10-6 C.

The iodine-127 nuclear quadrupole resonance spectrum temperature dependence for α-KIO3.HIO3 crystals was studied. A second order phase transition at 223 K was revealed. α-KIO3.HIO3 is a new ferroelectric with Curie point Tc=223 ± 2 K.

Antimonites of the general formula R3Sb5O12(R = Sc, In, La. Pr, Tb, Yb) represent a new structural family of crystals. At the temperature of hydrothermal growth (770-820 K) the crystals have a cubic lattice (space group 143 m), the unit cell dimensions being 10.42 to 11.14 A. On cooling all of them except Yb3Sb5O12 undergo completely reversible transformations. The salient features of these phase transitions are discussed.