4,366 research outputs found

    Experimental Study of the Effect of External Signal on Microwave Oscillations in a Nonrelativistic Electron Beam with Virtual Cathode

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    The effect of an external harmonic signal on the characteristics of microwave generation in a nonrelativistic electron beam with virtual cathode (VC) formed in a static retarding electric field (low-voltage vircator system) has been experimentally studied. A significant increase in the vircator generation power is observed when the frequency of the external signal is close to the frequency of VC oscillations. At large detunings, a broadband chaotic generation is observed.Comment: 3 pages, 2 figure

    Experimental and Theoretical Investigation into the Effect of the Electron Velocity Distribution on Chaotic Oscillations in an Electron Beam under Virtual Cathode Formation Conditions

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    The effect of the electron transverse and longitudinal velocity spread at the entrance to the interaction space on wide-band chaotic oscillations in intense multiple-velocity beams is studied theoretically and numerically under the conditions of formation of a virtual cathode. It is found that an increase in the electron velocity spread causes chaotization of virtual cathode oscillations. An insight into physical processes taking place in a virtual cathode multiple velocity beam is gained by numerical simulation. The chaotization of the oscillations is shown to be associated with additional electron structures, which were separated out by constructing charged particle distribution functions.Comment: 9 pages, 8 figure

    Поисковое значение дробного гранулометрического анализа в изучении алмазоносных россыпей

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    The article presents the novel data of fractional granulometric testing on the Syuzevskaya diamond placer located in the northern part of the Chikman-Nyar depression. The geological section was studied to a depth of 42,0 m. 18 samples weighing up to 200 kg each were taken, selected sectionally at two-meter intervals and graded into 10 granulometric classes on the gamma-Baturin scale. The obtained results have important search value: 1) the curve of the debris distribution by size is typical for the mature alluvium of the foothill river; 2) the paleo river alluvium is formed by a high dynamics flow and is fairly well sorted by size, which is a favorable sign for the concentration of large diamonds and indicates a slight dilution with non-diamond-bearing detrital material; 3) the presence of a typical mature alluvium in the paleovally indicates a long time of its existence, which is also a favorable search sign for industrial diamond placers. The methodology and results of the study can be used at various stages of the exploration cycle for placer minerals, including diamonds, all over the worldВпервые приведены данные дробного гранулометрического анализа отложений Сюзёвской россыпи алмазов, расположенной в северной части Чикман-Нярской депрессии на Среднем Урале. Разрез россыпи опробован на глубину 42,0 м. изучены 18 проб массой до 200 кг каждая, отобранные секционно двухметровыми интервалами и расситованные на десять гранулометрических классов по шкале γ-Батурина. Полученные результаты имеют важное прогнозно-поисковое значение: 1) кривая распределения обломков по крупности типична для зрелого аллювия предгорной реки; 2) аллювий палеореки сформирован потоком с высокой динамикой и достаточно хорошо отсортирован по крупности, что является благоприятным признаком для концентрации крупных алмазов и свидетельствует о незначительном разбавлении неалмазоносным обломочным материалом; 3) зрелый аллювий в палеодолине свидетельствует о длительном времени ее существования, что также является благоприятным поисковым признаком на промышленные россыпи алмазов. Методика и результаты исследования могут быть использованы на различных стадиях цикла геологоразведочных работ на россыпные полезные ископаемые, в том числе и алмазы, во всем мире

    Управление интеллектуальной собственностью: опыт университетов Европы

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    A comparative analysis of policies in the field of intellectual property (IP) of universities in leading European countries: Switzerland, the UK and the Netherlands. As a result of the comparison, the main components of these policies are identified as a single document: the purpose of the policy, the procedure for determining copyright holders, students' rights to IP, material incentives for using IP, and responsible structures. The policy of each university takes into account the features and traditions of its activities. It was revealed that each university has its own approach to material incentives for the creation and use of IP. The conditions are established under which the university does not claim to IP created by students. It is concluded that it is advisable to develop similar IP policies for Belarusian universities.Проведен сравнительный анализ политик в области интеллектуальной собственности (ИС) университетов ведущих стран Европы: Швейцарии, Великобритании и Нидерландов. В результате сравнения определены основные составляющие этих политик как цельного документа: цель политики, порядок определения правообладателей, права студентов на ИС, материальное стимулирование использования ИС, ответственные структуры. Политика каждого университета учитывает особенности и традиции его деятельности. Выявлено, что каждый университет имеет собственный подход к материальному стимулированию создания и использования ИС. Установлены условия, при которых университет не претендует на интеллектуальную собственность, созданную студентами. Сделан вывод о целесообразности разработки аналогичных политик в области ИС для университетов Беларуси

    Analysis of the influence parameters spine-pelvic balance on the risk of development degeneration and degenerative disease of adjacent segments after lumbar spine rigid fixation

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    Introduction An increase in the load on adjacent segments causes changes in the parameters of the spinal-pelvic balance and, as a consequence, the development of the so-called biomechanical «stress». Such pressures are a key link in the pathogenesis of degeneration, and in the presence of clinical and neurological manifestations of the latter and adjacent segment degenerative disease (ASD/ASDd).Objective of this study was to assess the effect of the parameters of the spinal pelvic balance on the risk of developing ASD/ASDd after dorsal decompression-stabilizing interventions (DDSI).Material and Methods The study included medical records of patients who underwent DDSI for lumbar spine degenerative diseases. Clinical and instrumental parameters were assessed.Results Based on the inclusion criteria, 98 patients (48 with signs of ASD/ASDd and 50 without) were included in the study. The average postoperative follow-up period for the respondents was 46.6 ± 9.8 months. If PI/ LL parameters were <10 and the ratio of segmental and global lumbar lordosis (LIV-SI/LI-SI) was 50% or more, the incidence of ASD/ASDd was significantly lower in patients who underwent rigid lumbar stabilization surgery.Conclusion The values of PI/LL parameters and the ratio of segmental and global lumbar lordosis are obvious risk factors for the development of ASD/ASDd after rigid lumbar spine DDSI
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