Modeling frequency-time synchronization systems that use signals of common sources

Article presents results of design and implementation of system model that uses signal of a common source to synchronize geographically distributed time and frequency standards (so-called general coverage algorithm). The use of various processing (mutual correlation and matched filtering) and estimation of time signal position methods as well as taking into consideration of multipath in channel are essential peculiarities of the model. The model may be used for estimating potential precision of a wide class of synchronization systems and the possibility of using various signals and processing techniques in such systems.     

一种改进的基于FFT的信号插值算法

在传统运用FFT进行信号插值运算的基础上,提出了一种提高插值精度的改进算法.通过子序列重叠和裁剪,舍弃重建序列边缘误差较大的样点,再将相对准确的样点进行重组,从而大幅提高插值精度.实验结果表明:与Prasad等算法相比,在计算量增加3.1％的情况下,不同子序列长度对应的归一化均方误差平均下降至原来的1/19;在计算量增加2倍的情况下,不同子序列长度对应的归一化均方误差平均下降至原来的1/75.     

Mathematical dependence of the sorptivity of adsorbents with asphalt additives on their nature and structure

A stable dependence of the gas retentivity of carbon absorbents on the structure and polarity of their surface is found. This relation makes it possible to predict the sorption properties and determines their parameters from chromatographic data. The sorptivity of high-polarizability molecules is most affected not by the total volume of the micropores but rather by the width of the micropore-size distribution and the surface polarity of the sorbents.     

Analysis of pressure angles and special positions of parallel structure modules intended for mechanisms of relative manipulation

The mechanisms of relative manipulation with determined pressure angles and special positions are considered.     

Radiation nondestructive testing of structural modifications of hard alloys after cryogenic treatment

The processes that proceed in hard alloys under the action of ionizing radiation were studied after cryogenic treatment. Acoustic emission due to the liberation of the energy stored in a lattice was shown to occur upon the irradiation of hard alloys. The nondestructive testing of hard alloys was shown to allow the prediction of the life and behavior of a drilling tool under different types of treatment.     

Magnetic inspection of fatigue degradation of a high-carbon pearlitic steel

The effect of high-cycle fatigue loading of U10 steel specimens with a fine-lamellar pearlite structure that were a annealed for a short time on the character of variations of the tangential component of the magnetic induction vector of specimens in a residual-magnetization state has been studied. It was found that fatigue loading up to major fatigue-crack formation leads to an increase in the tangential component of the magnetic induction vector and to nonuniformity of the magnetic induction distribution along the length of a specimen. This is due to the spheroidization of cementite plates, which occurs in U10 steel specimens under a fatigue load. Major fatigue-crack formation is accompanied by the appearance of a clearly pronounced peak in the distribution of the tangential component of the magnetic induction vector. The magnetic measurement technique that was used allows us to record both structural changes and cracks that result from the fatigue degradation of high-carbon-pearlitic steel.     

Carrying capacity of braced soldered joints

The carrying capacity of a soldered joint with a brace on one side is investigated; the eccentric longitudinal tensile force is taken into account.     

Friction and wear of fuel assemblies in water-moderated reactors

Static and dynamic processes that involve frictional forces are experimentally studied. The frictional forces affect the stress of the fuel assembly in all stages of the life cycle.