The conductivity of direct and alternating current for graphite-like amorphous carbon films after annealing in vacuum at a temperature of 700 °C was studied. The I–V characteristics of such films are symmetrical. The I–V curve in logarithmic coordinates demonstrated the presence of two linear sections. A study of the frequency dependences of structures with a thin graphite-like amorphous carbon film showed a sharp increase in capacitance at low frequencies and a decrease in the high-frequency region. The increase in capacitance in the low-frequency region is explained by the Maxwell–Wagner polarization, which is observed in inhomogeneous dielectrics with conducting inclusions. The results of temperature measurements of resistance showed that at room temperatures, there is a mechanism of conduction of electrons with a variable jump length along localized states lying in a narrow energy band near the Fermi level. At the same time, with an increase in the injection current, an additional mechanism of hopping electrical transport with a variable jump length along localized states in the tail of the valence band arises, which leads to an increase in the conductivity of the films.

Despite obvious drawbacks of the resonant converter, such as complicated calculation, increased size and weight of the device, deviations of the circuit parameters from product to product, the resonant converter shows significant advantages in comparison with other. The task was to design the generator, which is built on a resonant topology.

X-ray methods for nondestructive control take the priority place if necessary to exercise quality control of a product, to define presence of defects and to execute expert researches. In the present work, an attempt is made to systematize some features in the design and construction of installations for X-ray non-destructive control using the example of developments conducted at St. Petersburg State Electrotechnical University "LETI".

The paper describes the experience of detecting defects in layered structures using microfocus tomography. The basic features of the equipment for microfocus tomography are given. The sizes of defects (pores and inclusions) and their location in the object are analyzed.

This study analyzes the earliest known case of surgical extraction of the lower third molars, observed in a cranial series from Pucara de Tilcara fortress (15th-16th centuries AD), northwestern Argentina, excavated in 1908-1910. Crania were transported to the Kunstkamera in 1910 under an exchange project. Traces of dental surgery were registered in the mandible of a male aged similar to 40. Both third molars had been extracted after the removal of soft tissues and parts of the alveoli. Teeth were extracted by scraping alveolar walls with semicircular movements. The results of scanning electron microscopy, X-ray fluorescence, and X-ray microanalysis suggest that a stone tool was used. The results of macroscopic and CT analysis suggest that the surgery was motivated by the exacerbation of chronic periodontal disease and probably by caries. The left third molar was extracted without complications 2-3 months before the individual's death. On the right side, the pathological process continued, culminating in osteomyelitis and its complications. The surgeon's skill notwithstanding, the extraction of the right third molar did not cure the patient, who died, apparently following the destructive stage of acute osteomyelitis complicated by orofacial phlegmon. Our findings suggest that the level of dental surgery practiced in the Inca Empire was ahead of the diagnostic expertise.