No abstract

Fluctuations of the apparent center of radiation near their expectation during the irradiation of distributed objects with probing signals from radar stations have been observed by scientists for many decades. An expression describing the statistical nature of such fluctuations is known in the literature. These fluctuations are called angular noise. With all this, there is still no expression connecting the angular dimensions of the object and the distribution parameters of its angular noise. This expression is necessary to predict the angular size of distributed objects in problems of simulating reflections from them. In the article, the problem indicated above is solved in two ways. When using the first method, it is possible to obtain an unambiguous relationship between the angular size of the object and the distribution parameters of its angular noise, but for each new object it is necessary to re-derive this relationship, which is not always possible. When using the second method, the probability is used with which the fluctuating apparent center of radiation of a signal reflected from a distributed object falls within the boundaries of this object. This method has no disadvantage of the first one. The results presented in this article were confirmed by means of mathematical modeling.

O propósito deste artigo é o de identificar o léxico de origem não nativa na língua indígena Mẽbêngôkre (família Jê, tronco Macro-Jê), falada pelos povos Kayapó e Xikrin no Pará, bem como pelos Kayapó Mẽtyktire (Txucarramãe) no norte de Mato Grosso. São propostas novas etimologias de contato para diversas palavras Mẽbêngôkre, incluindo waxi ‘linha’, benorã ‘tucunaré’, awo ‘tipo de árvore; barco de cortiça, ubá’, ixe ‘espelho’ (da língua Xambioá); môtôbi’y ‘amendoim’, xãn ‘gato’, mokà ‘mocó’, xoko ‘socó-boi’ (da Língua Geral Amazônica), karaxu ‘colher’ (da língua Yudjá), dentre outras; além disso, são identificados alguns empréstimos de origem Mẽbêngôkre em outras línguas. O artigo conclui com uma proposta de síntese da história migratória dos povos Jê Setentrionais baseada tanto nos resultados deste estudo como em publicações anteriores

The analytic expression of quadrature components autocorrelation of signals from surface-distributed object reflectors density distribution function has been acquired and analyzed.

Radio lenses are often used as collimators. It is allow to convert a spherical phase front into a flat one, corresponding to the far zone of the electromagnetic wave source. The paper is dealt with the manufacturing of radio lenses from gas-filled materials. The sequence of actions performing which it is possible to make a radio lens from a gas-filled material is described. The results of experimental studies of a radio lens manufactured with using the proposed technology are presented. Studies are carried out with using an electromagnetic field scanner in the X-band. It is established that the use of a radio lens from a gas-filled material leads to equalization of the antenna aperture phase front. The use of lenses made of gas-filled material improves the shape of the antenna pattern significantly. This is confirmed by the graphs presented in the work and the fact that the use of a radio lens reduces the value of the integral error by approximately two orders of magnitude.