We report observations of color in the inner coma Comet C/2013 UQ4 (Catalina) with broadband B and R filters. find significant temporal variations slope, ranging from -12.67 $\pm$ 8.16 \% per 0.1~$\mu$m up to $35.09 \pm 11.7$ 0.1~$\mu$m.It is that comet changes red blue over only a two-day period. Such dispersion cannot be characterized an average slope. also observe infrared using Spitzer no CO/CO$_{2}$ gaseous species its coma. Therefore, we classify as dust-rich attribute measured slope...

The defective layered periodic structures (defective photon crystals), bordering upon plasma-like media (semiconductors and metals), arouse considerable interest. This is due to the fact that in such there are electromagnetic waves of different types. properties these have not been adequately investigated yet. TM-electromagnetic one-dimension dielectric structure, a medium, studied this paper on basis numerical solution dispersion equation. energy plasma modes depending location layer...

The spin filtering effect of the electron current in a double-barrier resonant-tunneling diode (RTD) consisting ${\mathrm{Zn}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{Se}$ semimagnetic layers has been studied theoretically. influence distribution magnesium ions on coefficient polarization investigated. dependence degree external magnetic field and bias voltage obtained. total predicted. This is characterized by suppression spin-up component current, which takes place when Fermi level...

Theoretical analysis of the magnetoresistance ferromagnetic-metal--insulator--ferromagnetic-metal (FM/I/FM) tunnel junction within a two-band model free electrons in ferromagnetic electrodes is presented. It shown that value and sign FM/I/FM depend essentially on height, width, effective electron mass potential barrier bias voltage. We show insulator parameters can be chosen such way both decreased increased as voltage increases.

The effect of reflectionless normal transit electromagnetic waves through symmetric threelayered structures containing negative-permittivity layers excites considerable interest. It is stipulated by both an unusual nature the and its unique technical applications. Moreover electromagnetic-wave has been investigated not enough all peculiarities have found described yet. By now considered only for some concrete values permittivity thickness a three-layered structure. In this paper more general...

Dynamically different groups of comets and active asteroids with orbits at 2 - 5 a. u. show dust activity in varying degrees forms. Photometric study comparison physical parameters can help to classify mechanisms nature the for such objects. We present new observations using broadband photometry 15 objects main asteroid belt surrounding regions obtained during 2012 2016. The aims compare properties main-belt (MBCs), quasi-Hilda (QHCs), (AAs). were carried out 0.7-m telescope Kyiv Comet...

The magnetoresistance of low-barrier magnetic tunnel junctions (MTJs) was studied within a two-band model free electrons in ferromagnetic electrodes, taking into consideration image forces. For MTJs with an MgO insulator, explanations are given the giant tunneling (TMR) effect and increasing TMR as width barrier increases. It is shown that electron current density through depend strongly on dielectric constant insulator. found reaches maximum at particular value applied bias voltage....

Currently much attention is paid to the investigation of electromagnetic properties defective photon crystals. This stipulated by both occurrence plasma and waves in such crystals zone nature wave spectrum. One most interesting resonance interaction waves. It found that resonant observed distinctly second forbidden band crystal. In this connection study electromagnetic-wave various types a topical problem. paper devoted effect onedimensional bordering on conducting medium subject condition...

In the articles nonlinear surface polaritons are investigated in semimagnetic semiconductors which a phase of antiferromagnetic ordering. It is shown that there exist two types characterized by nonotonic and non-nonotonic decaying electromagnetic field semiconductor. found with monotonic same frequency range as linear polaritons. out non-monotonic propagate non-passage for The influence electron plasma determined on dispersion properties

The dimensional accuracy of the «bushing» casting, manufactured under conditions automated foundry production, is monitored. real possibilities existing technological process for providing specified quality requirements to are established. systematic errors identified and their causes analyzed. described procedure, as an example, can be recommended use in CAD system production

The paper contains a statement of the problem to ensure performance characteristics military tracked and wheeled vehicles at stage design research. A method adapting generalized parametric modeling solving problems dynamics analysis durability elements vehicles. We consider particular associated with contact interaction vehicles, shock wave loading hulls light armored cars, impact jet forces on strength hulls, as well kinetic ammunition obstacle. During study used modern software systems....

Periodic comets of different dynamical groups with orbits at 2–5 AU still occasionally active. The observed dust activity such objects can be connected the processes water ice sublimation (MBCs) or crystallisation amorphous (QHCs) as well external causes. Despite absence connections between cometary flares and cyclic variations solar indexes, some individual affect brightness comets. Cometary in main asteroid belt have lower statistic than similar to quasi-Hilda objects.

We present the results of short observational program for asteroid 6478 Gault with using V and R Johnson filters realized at Kyiv Comet Station during January-April 2019. Color indices distribution brightness in comet-like tail were calculated. made a comparative analysis circumstances activity others morphologically similar active Main Belt asteroids.

The study of the defective periodic layered structures bordering upon plasma-like media has attracted interest recently. This is due to fact that in such there are surface and bulk electromagnetic waves interacting resonantly. effect resonant interaction not sufficiently studied. In paper TM-electromagnetic one-dimensional dielectric structure placed a parallel-plate waveguide investigated on basis numerical solution dispersion equation. energy properties plasma modes studied accordance with...

ВЛИЯНИЕ ДИЭЛЕКТРИЧЕСКОЙ ПОСТОЯННОЙ КРИСТАЛЛИЧЕСКОЙ РЕШЕТКИ ПРОВОДЯЩЕЙ СРЕДЫ НА РЕЗОНАНСНОЕ ВЗАИМОДЕЙСТВИЕ ЭЛЕКТРОМАГНИТНЫХ ВОЛН В СТРУКТУРЕ ДЕФЕКТНЫЙ ФОТОННЫЙ КРИСТАЛЛ-ПРОВОДНИКДефектные фотонные кристаллы, граничащие с твердотельными плазмоподобными средами, привлекают к себе большое внимание.Это связано наличием в таких структурах плазменных и дефектных волн, которые могут резонансным образом взаимодействовать между собой.Эффект резонансного взаимодействия различных типов электромагнитных...

О СПЕКТРЕ ЭЛЕКТРОМАГНИТНЫХ ВОЛН В ОДНОМЕРНОМ ДЕФЕКТНОМ ФОТОННОМ КРИСТАЛЛЕ, ГРАНИЧАЩЕМ С ПРОВОДЯЩЕЙ СРЕДОЙВ настоящее время большое внимание уделяется исследованию электромагнитных свойств дефектных фотонных кристаллов.Это связано как с наличием плазменных и волн в таких кристаллах, так зонным характером спектра этих волн.Одним из самых интересных кристаллов является резонансное взаимодействие волн.Установлено, что наиболее отчетливо наблюдается во второй запрещенной зоне фотонного...

Tunneling electrons through a non-stationary tunnel junction are investigated within the framework of approximation one-quantum electron junctions. The effect thermal energy distribution in emitter and collector is taken into account. dependence high-frequency current on frequency applied dc bias voltage found. influence barrier asymmetry active reactive parts studied.

The periodic layered structures bordering plasma-like media are of lively interest at present [1,2]. In these there new types the surface electromagnetic waves which possess unusual properties. When a defective layer places into structure, additional appear, called modes [3,4]. dispersion curves located in forbidden gaps structure. It should be expected that and interact with each other resonance way. Peculiarities spectral energy characteristics TM-electromagnetic one-dimensional dielectric...

The magnetoresistance of Fe/MgO/Fe magnetic tunnel junctions (MTJs) was studied taking into consideration image forces. For MTJs with an MgO insulator, explanations are given the giant tunneling (TMR) effect and increasing TMR increase in insulator thickness. It is demonstrated that electron current density through can be high enough to switch magnetization a ferromagnetic electrode.