The Problem of Adhesion Methods and Locomotion Mechanism Development for Wall-Climbing Robots

This review considers a problem in the development of mobile robot adhesion methods with vertical surfaces and the appropriate locomotion mechanism design. The evolution of adhesion methods for wall-climbing robots (based on friction, magnetic forces, air pressure, electrostatic adhesion, molecular forces, rheological properties of fluids and their combinations) and their locomotion principles (wheeled, tracked, walking, sliding framed and hybrid) is studied. Wall-climbing robots are classified according to the applications, adhesion methods and locomotion mechanisms. The advantages and disadvantages of various adhesion methods and locomotion mechanisms are analyzed in terms of mobility, noiselessness, autonomy and energy efficiency. Focus is placed on the physical and technical aspects of the adhesion methods and the possibility of combining adhesion and locomotion methods

Giant Magnetoresistance Oscillations Induced by Microwave Radiation and a Zero-Resistance State in a 2D Electron System with a Moderate Mobility

The effect of a microwave field in the frequency range from 54 to 140 $\mathrm{GHz}$ on the magnetotransport in a GaAs quantum well with AlAs/GaAs superlattice barriers and with an electron mobility no higher than $10^6$ $\mathrm{cm^2/Vs}$ is investigated. In the given two-dimensional system under the effect of microwave radiation, giant resistance oscillations are observed with their positions in magnetic field being determined by the ratio of the radiation frequency to the cyclotron frequency. Earlier, such oscillations had only been observed in GaAs/AlGaAs heterostructures with much higher mobilities. When the samples under study are irradiated with a 140-$\mathrm{GHz}$ microwave field, the resistance corresponding to the main oscillation minimum, which occurs near the cyclotron resonance, appears to be close to zero. The results of the study suggest that a mobility value lower than $10^6$ $\mathrm{cm^2/Vs}$ does not prevent the formation of zero-resistance states in magnetic field in a two-dimensional system under the effect of microwave radiation.Comment: 4 pages, 2 figur

Anisotropic positive magnetoresistance of a nonplanar 2D electron gas in a parallel magnetic field

We study the transport properties of a 2D electron gas in narrow GaAs quantum wells with AlAs/GaAs superlattice barriers. It is shown that the anisotropic positive magnetoresistance observed in selectively doped semiconductor structures in a parallel magnetic field is caused by the spatial modulation of the 2D electron gas.Comment: 4 pages, 3 figure

Large-Scale Structure Formation: from the first non-linear objects to massive galaxy clusters

The large-scale structure of the Universe formed from initially small perturbations in the cosmic density field, leading to galaxy clusters with up to 10^15 Msun at the present day. Here, we review the formation of structures in the Universe, considering the first primordial galaxies and the most massive galaxy clusters as extreme cases of structure formation where fundamental processes such as gravity, turbulence, cooling and feedback are particularly relevant. The first non-linear objects in the Universe formed in dark matter halos with 10^5-10^8 Msun at redshifts 10-30, leading to the first stars and massive black holes. At later stages, larger scales became non-linear, leading to the formation of galaxy clusters, the most massive objects in the Universe. We describe here their formation via gravitational processes, including the self-similar scaling relations, as well as the observed deviations from such self-similarity and the related non-gravitational physics (cooling, stellar feedback, AGN). While on intermediate cluster scales the self-similar model is in good agreement with the observations, deviations from such self-similarity are apparent in the core regions, where numerical simulations do not reproduce the current observational results. The latter indicates that the interaction of different feedback processes may not be correctly accounted for in current simulations. Both in the most massive clusters of galaxies as well as during the formation of the first objects in the Universe, turbulent structures and shock waves appear to be common, suggesting them to be ubiquitous in the non-linear regime.Comment: Review article. Accepted for publication in Space Science Reviews. It will appear as a contribution to an ISSI boo

Effect of parallel magnetic field on the Zero Differential Resistance State

The non-linear zero-differential resistance state (ZDRS) that occurs for highly mobile two-dimensional electron systems in response to a dc bias in the presence of a strong magnetic field applied perpendicular to the electron plane is suppressed and disappears gradually as the magnetic field is tilted away from the perpendicular at fixed filling factor $\nu$. Good agreement is found with a model that considers the effect of the Zeeman splitting of Landau levels enhanced by the in-plane component of the magnetic field.Comment: 4 pages, 4 figure

Anti-avoidance rules in Russian and German tax law: the comparison of collision resolution practices

Десятки исследований последних лет свидетельствуют о том, что проблема уклонения от уплаты налогов обрела настолько глобальные масштабы, что ни одна страна в одиночку не в состоянии с нею справиться. Для этого требуется принципиально иной, комплексный подход. Данные обстоятельства, а также политическая воля лидеров стран G20 в решении проблемы уклонения обусловили старт проекта по противодействию размыванию налоговой базы в виде плана из 15 рекомендуемых мероприятий различной направленности (так называемый, план BEPS). Воплощение этого плана в жизнь, применительно к России, предусматривается Основными направлениями налоговой политики на 2016 г. и плановый период 2017-2018 гг. и предполагает имплементацию выработанных предложений в национальное законодательство. Неизбежно последует усложнение и без того весьма разнообразного инструментария противодействия уклонению от уплаты налогов, что существенно повысит риски конкуренции различных институтов противодействия в правоприменительной практике, суды уже сталкиваются с проблемой коллизии институтов при разрешении конкретных дел. В связи с тем, что от выбора подлежащего применению института зависит исход всего дела, решение проблемы их соотношения имеет как теоретическое, так и важное прикладное значение. С целью поиска оптимальных подходов к разрешению существующих (предполагаемых) коллизий антиуклонительных норм в статье проводится сравнительный анализ положений российского и германского налогового права. Гипотеза исследования заключается в том, что конкуренция норм или институтов налогового права возможна при условии сопоставимости оснований их применения, выполнения ими одинаковой функции, но очевидной разницы в результатах применения для налогоплательщика. С учетом данной гипотезы выделяется пять основных функций антиуклонительных норм: выявление факта ненадлежащего исчисления и (или) уплаты налога; квалификация транзакций или деятельности налогоплательщика и определение их последствий для целей налогообложения; обеспечение взыскания суммы налога с налогоплательщика; наказание за уклонение от уплаты налогов; предотвращение уклонения от уплаты налогов. Классификация институтов, проведенная на основе этих функций, позволила выявить потенциальные коллизии между ними. На базе описания оснований и практики применения потенциально конкурирующих институтов, как в России, так и в Германии, предлагаются подходы, которые могут применяться для разрешения их коллизии в России.Dozens of research papers over the last years testify that the problem of tax avoidance has grown to such a global extend that no country is able to cope with it alone. To do this, a principally different, a new approach is required. These circumstances and the political will of the G20’ leaders towards solving the problem of tax avoidance determined the start of the project for counteracting the tax base erosion in the form of a scheme of 15 recommended action items of various orientations (so-called plan BEPS). Implementation of this plan envisaged by Main Directions of Taxation Policy for 2016 and Planned Period of 2017 and 2018, to be applied to Russia, assumes implementation of the elaborated proposals in the national legislation. The unavoidable resulting complicacy added to a variety of instrumentarium of counteracting tax avoidance will significantly increase the risks of competition between counteracting institutions in law enforcement practice. More than that, courts are already facing the problem of institutions’ collisions in solving cases. Allowing for the fact that the outcome of the whole case depends on selecting the proper application of the institution, so solving the problem of their correlation has both a theoretical and a rather important applied significance. In order to search for optimal approaches to solving the existing or assumed collisions of anti-avoidance norms, the article carries out a comparative analysis of provisions of the Russian and German taxation laws. The hypothesis of the research is that competition of the norms or taxation law institutions is made possible in terms of comparability of substantiation of their application, execution a similar function by them, yet with evident difference of application results for taxpayers. In terms of this hypothesis, the article identifies five main function of anti-avoidance norms: identifying a fact of inappropriate calculation and (or) tax payment; qualifying transactions of the taxpayer’s activity and determining their consequences for the tax purposes; providing recovery of the tax amount from the taxpayer; punishing for tax avoidance; preventing tax avoidance. Classification of the institutions carried on their basis allows to identify potential collisions between them. In terms of description of substantiations and application practice by competing institutions (both in Russia and Germany), the article gives a description of the approaches applied, in the author’s opinion, for solving their collisions in Russia

Ultrahard spectra of PeV neutrinos from supernovae in compact star clusters

Starburst regions with multiple powerful winds of young massive stars and supernova remnants are favorable sites for high-energy cosmic ray acceleration. A supernova shock colliding with a fast wind from a compact cluster of young stars allows the acceleration of protons to energies well above the standard limits of diffusive shock acceleration in an isolated SN. The proton spectrum in such a wind-supernova PeV accelerator is hard with a large flux in the high-energy-end of the spectrum producing copious gamma-rays and neutrinos in inelastic nuclear collisions. We argue that SN shocks in the Westerlund 1 cluster in the Milky Way may accelerate protons to about 40 PeV. Once accelerated, these CRs will diffuse into surrounding dense clouds and produce neutrinos with fluxes sufficient to explain a fraction of the events detected by IceCube Observatory from the inner Galaxy.Comment: 10 pages, 7 figures, MNRAS v.453, p.113-121, 201