40 year anniversary of the RADAN systems – compact pulsed power sources for various investigations

This article includes a brief overview of the compact RADAN-series subgigawatt pulsed voltage sources and describes their capabilities in various electrophysical researches. We present the results obtained in the experiments at nano- and subnanosecond time scales on the formation of the voltage pulses with a special shape, electron beams emission in air gaps and by the cold cathodes in vacuum, as well as generation of electromagnetic radiation. Particular attention is paid to the promising application of the RADAN systems.

SHIPS WITH SMALL WATER-PLANE AREA: THE MAIN INFORMATION

Ships with small water-plane area (below “SWA ships”) have very special shape of hulls. It is the reason of characteristic specificity of such ships. SWA ships usually are multi-hull ones. And as all multi-hulls, SWA ships differ from the comparable mono-hulls by bigger deck area relative the displacement and by simple ensuring of stability. There are some architectural types of SWA ships. Their differences are shown by the article. Relative area of deck and initial transverse stability of SWA ships are compared. Statistical data on performance: twin-hull SWA versus catamarans. Common specificity of and . The main external loads. Special method of designing. Main disadvantages. Conclusions, recommendation.

A New Optimized Solution for a Flexible Coupling with Bolts Used in the Mechanical Transmissions

The paper presents a new constructive and functional solution of flexible coupling with bolts and nonmetallic intermediary elements. The bolts have a special shape in the sense that they have a milled area on a certain length equal to the width of the non-metallic element, a cylindrical area that reduces the stress concentrators at the diameter passages. The novelty of this coupling consists of the existence of one intermediary disk between two semi couplings (driver and driven semi couplings). This is fixed by the semi-coupling on the right side, the intermediary disc having milled four locations in which to mount the left, as the right has a metal plate with a special shape of eight metallic plates that are mounted with screws in the four milled places processed on the intermediate disc. The nonmetallic elements have various forms and can be made from different qualities of rubber mounted on the bolts. Eight milled bolts (four on each semi-coupling) allow the transmission of the torsion moment in both directions of rotation, in one direction becoming rigid and thus behaving like a safety coupling. Finite element method is used to obtain the mechanical response of this new type of coupling.

THE DEPENDENCE OF THE ELECTRODYNAMIC CHARACTERISTICS OF THE MICROSTRIP PHASED ARRAY SUBARRAY ON THE METHOD OF POWER SUPPLY

Microwave technology in microstrip design is widely used in various antenna systems. The active use of phased array (PA) of this type makes developers around the world search for various options of its construction. To improve individual characteristics, in particular, expand the scanning angle, as well as optimize the configuration of the excitation of the PA, they use subarrays that combine a given number of elements of the entire array. In this paper, we considered various options for constructing microstrip PA subarrays made on a homogeneous substrate from a high-frequency laminate GIL_GML 1000, in particular, various methods for their excitation. Using modern, accurate 3D electrodynamic modeling environment and HF device analysis, we studied changes in the electrodynamic characteristics of the simulation model of a multi-element microstrip PA subarray, depending on how the excitation is organized. This article discusses three simulation models of subarrays for microstrip PA with various options for their excitation. All subarrays have a radiation pattern of a special shape. After calculating the main characteristics, the issue of the most preferred organization of subarray power supply for the developed PA was solved. It is shown that in practice, the study of parameters and decision-making on the design of complex microwave devices, possibly without expensive field modeling.