Электрохимическая миграция: этапы и профилактика

The modern trend of miniaturization of electronics has also affected the aviation industry. With each new generation of aviation electronics (avionics), the layout of electronic components becomes smaller and smaller. This led to a significant complication of all electronic components of avionics in general, as well as compaction topology of printed circuit board (PCB) used in avionics, in particular. Any complication of electronic equipment, and especially important facilities, leads to increased requirements for reliability. Given that the aircraft equipment is operated almost constantly in extreme conditions, even the slightest probability of failure is unacceptable. That is why the physical reliability of avionics is so important. One of the factors significantly reducing the physical reliability of aviation electronics is electrochemical migration.Electrochemical migration can lead to failures in the operation of aviation electronics, to its complete failure, and even to a fire outbreak on the aircraft. Now the electrochemical migration is explored badly. Only the factors causing it and the consequences of electrochemical migration are determined, and the existing way of struggle it is either ineffective or significantly increase the weight and cost of aircraft equipment set, so that their use becomes impractical.This article presents experimental studies of the kinematics of electrochemical migration, the consequences of its occurrence, as well as, the way of struggle of the occurrence of electrochemical migration with the analysis of experimental data.Современная тенденция миниатюризации электроники затронула и авиационную промышленность. С каждым новым поколением авиационной электроники (авионики) компоновка электронных узлов становится все меньше и меньше. Это привело к значительному усложнению всех электронных узлов авионики в целом, а также уплотнению топологии печатных плат, использующихся в авионике в частности. Любое усложнение электронной аппаратуры, а особенно аппаратуры ответственного назначения, приводит к повышению требований к надежности. Учитывая, что авиационная аппаратура эксплуатируется практически постоянно, в экстремальных условиях, даже малейшая вероятность возникновения сбоя или отказа недопустима. Именно поэтому физическая надежность авионики настолько важна. Одним из факторов, существенно снижающим физическую надежность авиационной электроники, является возникновение электрохимической миграции.Электрохимическая миграция способна привести к сбоям в работе авиационной электроники, к ее полному отказу, а также даже к возгоранию на борту летательного аппарата. На сегодняшний день явление электрохимической миграции изучено достаточно плохо. Определены лишь факторы, вызывающие ее, и последствия электрохимической миграции, а существующие способы борьбы с этим явлением либо неэффективны, либо значительно увеличивают вес и стоимость бортовой аппаратуры настолько, что их использование становится нецелесообразным.В данной статье приводятся экспериментальные исследования кинематики явления электрохимической миграции, последствий ее возникновения, а также с учетом проведенного анализа экспериментальных данных предложен способ борьбы с возникновением явления электрохимической миграции

Update on the Combined Analysis of Muon Measurements from Nine Air Shower Experiments

Over the last two decades, various experiments have measured muon densities in extensive air showers over several orders of magnitude in primary energy. While some experiments observed differences in the muon densities between simulated and experimentally measured air showers, others reported no discrepancies. We will present an update of the meta-analysis of muon measurements from nine air shower experiments, covering shower energies between a few PeV and tens of EeV and muon threshold energies from a few 100 MeV to about 10GeV. In order to compare measurements from different experiments, their energy scale was cross-calibrated and the experimental data has been compared using a universal reference scale based on air shower simulations. Above 10 PeV, we find a muon excess with respect to simulations for all hadronic interaction models, which is increasing with shower energy. For EPOS-LHC and QGSJet-II.04 the significance of the slope of the increase is analyzed in detail under different assumptions of the individual experimental uncertainties

Search for Spatial Correlations of Neutrinos with Ultra-high-energy Cosmic Rays

For several decades, the origin of ultra-high-energy cosmic rays (UHECRs) has been an unsolved question of high-energy astrophysics. One approach for solving this puzzle is to correlate UHECRs with high-energy neutrinos, since neutrinos are a direct probe of hadronic interactions of cosmic rays and are not deflected by magnetic fields. In this paper, we present three different approaches for correlating the arrival directions of neutrinos with the arrival directions of UHECRs. The neutrino data are provided by the IceCube Neutrino Observatory and ANTARES, while the UHECR data with energies above ∼50 EeV are provided by the Pierre Auger Observatory and the Telescope Array. All experiments provide increased statistics and improved reconstructions with respect to our previous results reported in 2015. The first analysis uses a high-statistics neutrino sample optimized for point-source searches to search for excesses of neutrino clustering in the vicinity of UHECR directions. The second analysis searches for an excess of UHECRs in the direction of the highest-energy neutrinos. The third analysis searches for an excess of pairs of UHECRs and highest-energy neutrinos on different angular scales. None of the analyses have found a significant excess, and previously reported overfluctuations are reduced in significance. Based on these results, we further constrain the neutrino flux spatially correlated with UHECRs

Search for Spatial Correlations of Neutrinos with Ultra-high-energy Cosmic Rays

International audienceFor several decades, the origin of ultra-high-energy cosmic rays (UHECRs) has been an unsolved question of high-energy astrophysics. One approach for solving this puzzle is to correlate UHECRs with high-energy neutrinos, since neutrinos are a direct probe of hadronic interactions of cosmic rays and are not deflected by magnetic fields. In this paper, we present three different approaches for correlating the arrival directions of neutrinos with the arrival directions of UHECRs. The neutrino data are provided by the IceCube Neutrino Observatory and ANTARES, while the UHECR data with energies above ∼50 EeV are provided by the Pierre Auger Observatory and the Telescope Array. All experiments provide increased statistics and improved reconstructions with respect to our previous results reported in 2015. The first analysis uses a high-statistics neutrino sample optimized for point-source searches to search for excesses of neutrino clustering in the vicinity of UHECR directions. The second analysis searches for an excess of UHECRs in the direction of the highest-energy neutrinos. The third analysis searches for an excess of pairs of UHECRs and highest-energy neutrinos on different angular scales. None of the analyses have found a significant excess, and previously reported overfluctuations are reduced in significance. Based on these results, we further constrain the neutrino flux spatially correlated with UHECRs

Search for Spatial Correlations of Neutrinos with Ultra-high-energy Cosmic Rays

For several decades, the origin of ultra-high-energy cosmic rays (UHECRs) has been an unsolved question of high-energy astrophysics. One approach for solving this puzzle is to correlate UHECRs with high-energy neutrinos, since neutrinos are a direct probe of hadronic interactions of cosmic rays and are not deflected by magnetic fields. In this paper, we present three different approaches for correlating the arrival directions of neutrinos with the arrival directions of UHECRs. The neutrino data are provided by the IceCube Neutrino Observatory and ANTARES, while the UHECR data with energies above ∼50 EeV are provided by the Pierre Auger Observatory and the Telescope Array. All experiments provide increased statistics and improved reconstructions with respect to our previous results reported in 2015. The first analysis uses a high-statistics neutrino sample optimized for point-source searches to search for excesses of neutrino clustering in the vicinity of UHECR directions. The second analysis searches for an excess of UHECRs in the direction of the highest-energy neutrinos. The third analysis searches for an excess of pairs of UHECRs and highest-energy neutrinos on different angular scales. None of the analyses have found a significant excess, and previously reported overfluctuations are reduced in significance. Based on these results, we further constrain the neutrino flux spatially correlated with UHECRs