Radial dynamics of electrons in two-section linear accelerator

This article discusses possibility of harness wiring with the use of focusing system of high frequency eigenfields of accelerating resonators in standing wave linear accelerators on the basis of biperiodic slowing systems. The scopes of business activities and specificity of existing engineering processes applied in industry, especially in chemistry and metallurgy, require for special measures on environmental protection. At present electron linear accelerators operating in pulse mode are used for application purposes. Such accelerators can be characterized by sufficient beam power for efficient industrial use and for environmental protection. The results of numerical analysis of electron dynamics in two-section accelerator upon various initial conditions are presented. The obtained results are applied for development of actual accelerator, calculated and experimental data are given. The performed experimental study confirmed possibility of development of standing wave linear accelerator without external magnetic focusing system with output beam diameter of not higher than . The results of calculations of beam dynamics are experimentally verified

Focusing Properties of a Modified Retarding Structure for Linear Electron Accelerators

When using accelerators in industry and medicine, important are the dimensions of the device used, especially the radial ones. In the linear electron accelerators based on a biperiodic retarding structure, which operates in the standing wave mode, there is a possibility to provide focusing of the accelerated particles with the help of high-frequency fields without the use of external focusing elements. In the accelerating cell, due to the presence of the far protruding drift sleeves, the electric field lines become strongly curved, which leads to the appearance in the regions adjacent to these sleeves of a substantial in magnitude radial component of the electric field. The particles entering the accelerating gap experience the action of a force directed toward the axis of the system, and at the exit, of a force directed away from the axis. Under certain conditions, alternation of the focusing and defocusing fields can lead to a general focusing effect. In the paper we study the focusing properties of a modified biperiodic structure with standing wave. The main attention is paid to the possibility of using the focusing properties of the electromagnetic accelerating field for guiding the electron beam through the aperture of the accelerating system, which will lead to a significant reduction in the accelerator sizes. The proposed method can be applied in the calculation and design of linear electron accelerators

DESIGN OF ROADS ON APPROACHES TO A MOUNTAIN PASS

The paper dwells upon various designs of roads on approaches to a mountain pass with the use of loops and serpentines. When designing serpentines it has been offered to calculate the magnitude of the transition curve on the base curve taking into consideration the optimum safety speed, and on the reversed curve - the speed provided by the basic curve rather than its radius. This allows to adjust a road layout to the relief form at the most, causing minimum possible damage to the environment. It has been recommended to lay a road on the approaches to a mountain pass focusing not on the limiting for the given road category longitudinal gradient, but on the ruling one, which is smaller than the limiting by the value of its decreasing on curvatures of small radii. The value of decreasing the limiting longitudinal gradient for roads located in the mountain massif of Central Asia, taking into account the position of the ridge in the mountain massif and slope exposure has been determined. The use of loops and serpentines for development of roads on a mountain slope has been calculated. Their comparison has been made. In many respects, the loop turned out to be more preferable than serpentines.</jats:p

Absolute summation of series by the Rogosinski-Bernstein method

Kuz'mich, V. I. Absolute summation of series by the Rogosinski-Bernstein method / V. I. Kuz'mich // Ukrainian Mathematical Journal. - 1981. - Volume 33, Issue 3. - pp. 307-313

Favard's method of summation of series

Kuz'mich, V. I. Favard's method of summation of series / V. I. Kuz'mich // Ukrainian Mathematical Journal. - 1983. - Volume 35, Issue 2. - pp 192-194

Holocene oxygen isotope record of diatoms from Lake Kotokel (southern Siberia, Russia) and its palaeoclimatic implications

The oxygen isotope composition of diatom silica (d18Odiatom) from marine and lake sediments is helpful for the interpretation of the past climate and environments, especially when complemented by other proxy records. This paper presents a Holocene oxygen isotope record of diatoms from Lake Kotokel, located 2 km east of Lake Baikal in southern Siberia, Russia. The isotope record displays variations in d18Odiatom from +23.7 to +30.3‰ from about 11.5 ka BP until today. Comparing the isotope composition of recent Lake Kotokel water (mean d18O = -12‰) to that of the most recent diatom sample (d18O = +27.5‰), an isotope fractionation in the right order of magnitude was calculated. The Kotokel d18O diatom record is rather controlled by changes in the isotopic composition of the lake water rather than by lake temperature. Lake Kotokel is a dynamic system triggered by differential environmental changes closely linked with various lake-internal hydrological factors. A continuous depletion in d18O of 6.6‰ is observed from Early to Late Holocene, which is in line with other hemispheric environmental changes (i.e. a Mid- to Late Holocene cooling). Enhanced evaporation effects and higher relative supply from a southerly moisture source explain the relatively heavy isotopic composition in a rather cold Early Holocene. In summary, changes in the Holocene d18O diatom record of Lake Kotokel reflect variations in d18O of precipitation linked with both Tair as well as evaporation effects and, to a lesser degree, meltwater pulses from the mountainous hinterland and changing atmospheric moisture sources