Substrate modification influence on properties of nanocomposite based on TiO2 and gold nanoparticles

In this work, we study photo-induced current transfer through nanocomposite structures consisting of the TiO2 coating activated with plasmonic gold nanoparticles on top of pillar-like structured SiO2. It is shown that the photo-response of the nanocomposite can be adjusted via tuning of the heterostructure topology. Processes at the interface between silicon and noble metal nanoparticle play an important role in charge carrier photo-generation. The high photo-activity in visible part of spectrum has been found in the composite, containing pillar-like silicon dioxide nanostructures [1]. The electron transport via the SiO2 layer from the potential well at the TiO2-SiO2 interface to the n-Si conduction band was explained by electron tunneling mechanism. We present the empirical qualitative model which explains experimental results and helps to separate the contributions of different transport mechanisms

Multiwavelength monitoring and reverberation mapping of a changing look event in the Seyfert galaxy NGC 3516

We present the results of photometric and spectroscopic monitoring campaigns of the changing look AGN NGC 3516 carried out in 2018 to 2020 covering the wavelength range from the X-ray to the optical. The facilities included the telescopes of the CMO SAI MSU, the 2.3-m WIRO telescope, and the XRT and UVOT of Swift. We found that NGC 3516 brightened to a high state and could be classified as Sy1.5 during the late spring of 2020. We have measured time delays in the responses of the Balmer and He ii λ4686 lines to continuum variations. In the case of the best-characterized broad H β line, the delay to continuum variability is about 17 d in the blue wing and is clearly shorter, 9 d, in the red, which is suggestive of inflow. As the broad lines strengthened, the blue side came to dominate the Balmer lines, resulting in very asymmetric profiles with blueshifted peaks during this high state. During the outburst the X-ray flux reached its maximum on 2020 April 1 and it was the highest value ever observed for NGC 3516 by the Swift observatory. The X-ray hard photon index became softer, ∼1.8 in the maximum on 2020 April 21 compared to the mean ∼0.7 during earlier epochs before 2020. We have found that the UV and optical variations correlated well (with a small time delay of 1–2 d) with the X-ray until the beginning of 2020 April, but later, until the end of 2020 June, these variations were not correlated. We suggest that this fact may be a consequence of partial obscuration by Compton-thick clouds crossing the line of sight.</p

Seborrheic dermatitis in patients with psychoneurological disorders

Seborrheic dermatitis (SD) is a chronic inflammatory skin disease. Genetic predisposition, hormonal disorders, neurohumoral, metabolic, and immune changes play an important role in the development of this disease. All these factors lead to activation of pathogenic microbial flora and development of the skin rash characteristic of SD. Malassezia fungus is currently believed to be the main etiological factor in the development of SD. In this paper, the authors draw attention to the characteristic features of seborrheic dermatitis in patients with neuropsychiatric disorders. Authors report their own observations. The use of Nizoral shampoo twice a week for 1 month was recommended as a topical therapy. In 58.3% of patients, no symptoms of seborrheic dermatitis were observed 1 month after administration of Nizoral shampoo. In 41.7% of patients, there was no itching and peeling, but minor hyperemia at the areas of rash was preserved. After the end of therapy, a two-month-long remission was observed in2/3 of patients, while others had only slight peeling. In view of the intense sebostatic effect of 2% ketoconazole, it can be recommended for the use in the form of shampoo for treatment and prevention of seborrheic dermatitis in patients at specialized institutions. The ease of use greatly facilitates the care for patients with psychoneurological disorders. © 2015, Media Sphera Publishing Group. All rights reserved

Features of formation of small-scale wave disturbances during a sudden magnetospheric compression

Quasi-periodic changes of the geomagnetic field and plasma parameters in the range of Pc 5 pulsations, which occurred immediately after the interaction of interplanetary shock (IPS) with Earth’s magnetosphere in the event of April 24, 2009 at 00:53 UT are examined using ground and satellite observations. The pulsations were localized at latitudes 66–74° in the noon (11 MLT) and evening (20 MLT) sectors. The analysis of hodographs of the geomagnetic field changes both from satellite and ground observations has shown the presence of vortical disturbances. In this event, both the IPS front in the interplanetary medium and the compression wave front in the magnetosphere had a slope in the ZGSM=0 plane; the inclination angle was 14° in the interplanetary medium and 34° in the magnetosphere

Автоэмиссионные свойства пленок никель - углеродного нанокомпозита

Field-emission properties of Ni-C nanocomposite thin films were experimentally studied. The films were deposited at Si substrates using CVD technique with a metalloorganic precursor and were composed by nm-scale grains of metallic Ni bounded with a carbonic weakly-conducting matrix. In the samples with lower effective thickness, the Ni particles were separated from each other. Such films showed capability of facilitated emission with threshold field values as low as a few V/μm. Thicker coating samples, with metallic particle merged in a conductive layer, required annealing at 470-600 °С in vacuum to produce low-field emission current. The observed emission behavior agrees with the previously proposed model considering low-field emission from nanostructured carbonic materials as a multi-stage process involving generation of hot electrons at interface boundaries.Были исследованы автоэмиссионные свойства тонких пленок никель-углеродного нанокомпозита. Пленки наносились на кремниевые подложки методом химического осаждения с использованием металлорганического прекурсора. Их структура включала в себя наноразмерные зерна металлического никеля, связанные слабопроводящей углеродосодержащей матрицей. В случае покрытий малой эффективной толщины, частицы никеля были отделены друг от друга. Такие пленки демонстрировали способность к низковольтной эмиссии в полях с напряженностью от нескольких В/мкм. В более толстых покрытиях металлические частицы образовывали единый электропроводящий слой. В этом случае для наблюдения низковольтной эмиссии требовался отжиг образцов в вакууме при 470-600 °С. Наблюдавшиеся закономерности эмиссии согласуются с предлагавшейся ранее моделью, которая рассматривает низковольтную эмиссию из наноуглеродных материалов как многостадийный процесс с участием горячих электронов, образующихся на внутренних междоменных границах