Investigated resonant tunneling through defect levels in h-BN barrier van der Waals heterostructures. The effect of multiplication of tunnel resonances through these levels was found, due to the influence of a high degree of defectiveness of the structure of the neighboring layer of graphene, created by intentionally processing in plasma. Various mechanisms of such influence are discussed.

The behavior of Al 2 O 3 ceramics having a 50% volume of pore space under compression is studied. The porous structure includes three types of pores: large porosity with an average size of 120 μm, small porosity with an average size of 2 μm, and extended porous channels (about 150 μm) formed as a result of zonal separation during sintering. It is shown that at a load of ceramics with such a multilevel pore structure, the microdamage accumulates over the entire volume of the sample. It causes decreasing the scale level of fracture from microscopic (in the case of ceramics with unimodal pore structure) to meso- and microscale (for ceramics with a multilevel pore structure). Residual deformation in such material appears at small loads of about 0.3σ c due to displacements of blocks and their groups during deformation before the ultimate strength.

It has been studied the behavior under compression tests of alumina ceramics with multilevel pore structure. The porosity approximately was 50% and included pores of three types - large pores with an average size of 120 µm, small porosity with an average size of 2 µm and extended pore channels about 150 µm length formed as a result of zonal shrinkage during sintering. It was shown that during loading of material with this multilevel pore structure there are arising micro-damages in whole sample and as result in a lowering a scale level of fracture from macro- to meso- and microlevel. Residual strain is appears even at a very low stresses smaller 30% of material strength only due to movements of separate blocks formed after sintering.

The evolution of the manifestation of levels of defects in h-BN in tunneling through graphene/h-BN/graphene heterostructures with various degrees of perfection, from completely defectless to those with several tens of levels in the band gap of h-BN, has been studied. It has been shown that the behavior of these levels is related to the motion of Dirac points and the chemical potentials of graphene layers at change in the bias and gate voltages, which is described by the electrostatic model of an ideal defectless heterostructure. The density of states of graphene in a magnetic field has been studied by its probing by the level of a single defect with a sensitivity allowing the detection of splitting of the zeroth Landau level caused by the lifting of the spin and valley degeneracy already at B ∼ 4 T.

Structural magnetic elements observed in sunspot penumbrae are employed as indicators of motions occurring in and around penumbrae. The analysis presented here is base on SDO/HMI continuum images and magnetograms of the line-of-sight field obtained for the active region NOAA 11117. In a first approximation, the penumbral magnetic fields can be considered alternating spines and interspine filaments. In the plane of the sky, spines are thin radial elements with higher field strengths and lower magnetic-field inclinations compared with those in surrounding areas. It is confirmed that spines first appear as protrusions of the umbra magnetic fields visible in magnetograms, and then develop simultaneously with the growth of the penumbra. The departure of magnetic elements from penumbrae as a result of the detachment of the ends of spines begin 1–1.5 h after the spine formation. Inmature penumbrae, magnetic elements emerge fairly often, and the departure of groups of field elements sometimes generates structures resembling moving ribbons. The velocities of magnetic elements that have separated from spines are a factor of two to three lower than those of elements that have separated from inter-spine filaments. The results obtained agree well with an “uncombed” model for the penumbral magnetic fields.

В физике Солнца все большее внимание уделяется регулярным долговременным измерениям магнитных полей, охватывающим всю солнечную поверхность. Только обладая такой информацией, можно (и то при определенных предположениях) рассчитывать параметры гелиосферы, предсказывать геоэффективные явления. Поэтому созданию инструментов, способных обеспечивать такие наблюдения, в мире уделяется значительное внимание. С целью создания в России современного телескопа, способного выполнять полнодисковые и полновекторные измерения с высоким пространственным и временным разрешением, несколько лет назад в ИСЗФ СО РАН, в сотрудничестве с АО ЛОМО, были начаты работы по разработке и созданию нового солнечного инструмента, которому, исходя из его основных научных целей, было дано название СОЛСИТ – Солнечный синоптический телескоп. В июне 2017 г. СОЛСИТ был установлен в специально построенной башне в Байкальской астрофизической обсерватории и начаты работы по организации на нем регулярных наблюдений. В докладе приводятся основные сведения об оптической схеме и конструктивных элементах СОЛСИТ.

The compaction behavior is studied in Al2O3 ceramics with a pore space volume in the range from 35 to 60% and with the following three types of hierarchical pore structure: coarse porosity with a size of 80 to 100 μm, fine porosity with a size of 14 to 15 μm, and intermediate interblock porosity comprised of elongated (110–120 μm) porous microchannels formed as a result of zonal isolation during sintering. It is shown that the obtained hierarchical porous structure causes the formation of a hierarchical deformation structure in the volume of ceramics and leads to a decrease in the extent of destruction processes from the macroscopic scale in the case of unimodal ceramics to the microscale destruction comparable with the sizes of the blocks formed during sintering.

Изучено поведение при сжатии керамики Аl2O3 с объeмом порового пространства от 35 до 60% с иерархической поровой структурой трeх видов: крупной пористости размером 80-100 mum, мелкой пористости размером 14-15 mum и промежуточной межблочной пористости, включающей протяженные (110-120 mum) поровые микроканалы, образованные в результате зонального обособления при спекании. Показано, что полученная иерархическая поровая структура обусловливает формирование иерархической деформационной структуры в объеме керамики и приводит к понижению масштаба процессов разрушения от макроскопического в случае унимодальной керамики до микромасштабного разрушения, сравнимого с размерами сформировавшихся при спекании блоков. DOI: 10.21883/PJTF.2017.15.44874.16652

The formation of the penumbra of the leading spot of the active region NOAA 11117 has been studied using data fromthe Solar DynamicObservatory (SDO). HMI data on longitudinal magnetic fields, line-of-sight velocities, and continuum images were used. The appearance of localized upflows between the umbra and undisturbed photosphere precedes the penumbra formation. The sizes of them reach 1.5″–2″ and the velocity increases to 1 km/s over several minutes. These localized upflows change themselves to a region of material flowing horizontally from the penumbra (the Evershed effect). The formation of individual spine namely fine radial element of the penumbra magnetic field with higher strength and lower inclination than in the surrounding is traced for the first time. The formation of the spine manifests itself as appearance of region of 2″–3″ in size with enhanced upflow near the sunspot umbra, protrusion in longitudinal-field contours on one side of the upwelling center, and the subsequent appearance of magnetic pole of opposite polarity on the other side of the upwelling. This process is accompanied by a bending of the contour marking the boundary of the undisturbed photosphere, which puts the upwelling center in a zone of higher brightness. One possible explanation for this is the emergence of hot magnetic tube. The appearance and growth of the sunspot spines results in the formation of the penumbra.

The capabilities of the new medium- and low-resolution spectrograph installed recently on the 1.6-m AZT-33IK telescope at the Sayan Observatory of the Institute of Solar–Terrestrial Physics to solve the problems of ground-based optical support for the future all-skyX-ray survey of the SRGobservatory are discussed. Results of the test observations of galaxy clusters, active galactic nuclei (AGNs) and quasars, and cataclysmic variables performed immediately after the installation of the spectrograph on the telescope are presented. The results of these observations show that the AZT-33IK telescope equipped with the new medium- and low-resolution spectrograph can provide a substantial fraction of the necessary optical observations in the program of ground-based optical support for the all-sky survey of the SRG observatory.

Ⱦɨɥɹ ɞɢɫɫɢɩɢɪɨɜɚɧɧɨɣ ɜ ɦɚɬɟɪɢɚɥ ɜ ɩɪɨɰɟɫɫɟ ɨɞɧɨɤɪɚɬɧɨɝɨ ɢɧɞɟɧɬɢɪɨɜɚɧɢɹ ɷɧɟɪ-

The functional and metrological characteristics of a new solar telescope designed to obtain quantitative data on large-scale magnetic fields (LMF) of the Sun are considered. The full automation of measurements, the application of CCD matrices in image scanning and spectra recording systems, and the optical diagram corresponding to the main purpose of the telescope significantly increased the efficiency, quality, and accuracy of measurements of the LMF and expanded the range of tasks in comparison with existing telescopes. The developed automated system of telescope control, measuring system, and software for real-time processing of measurement results make it possible to obtain LMF magnetograms with the required accuracy for about 15 min.

The rare phenomenon of the coalescence of two rotating sunspots of the same magnetic polarity during the emergence of the active region NOAA 11117 is investigated using data from the SDO space observatory. The coalescing spots rotated in opposite directions. The leading spot which formed from this process rotated counterclockwise with an angular velocity of 4°/h. A possible explanation is presented, based on a model of the emerging, twisted magnetic Ω flux tube that interacts with convective flows as it crosses the convective zone.

We are considering of new devices for solar astronomical telescope as a tools for adaptive optics correction. One of them is a high precision Shack-Hartmann wave-front sensor has been developed on the basis of a low-aperture offaxis diffraction lens array. The second device is image quality analyzer. Efficiency of the adaptive optical in system of the imaging is valued by quality of the updated image.