The Nonuniformity of the Light Yield in Scintillator Strips with Wavelength-Shifting Fibers of the DANSS Detector

The transverse nonuniformity of the light yield in scintillator strips of the DANSS detector was investigated on a test setup that was specially designed for this purpose using proportional chambers with a wire pitch of 1 mm. It is shown that using the approaches that were used in the DANSS experiment, the variation in the light yield due to the geometric features of the strip design is approximately 8% for a minimum ionizing particle. This study can be useful for making estimates and designing similar detectors.     

Control of flight parameters of a quadrotor vehicle moving over a given trajectory

The problem of control of an autonomous unmanned aerial vehicle with vertical takeoff and landing, which moves over a trajectory specified in the coordinate space, is considered. A method of constructing a system of automatic control of quadrotor vehicle takeoff and flight is proposed. Analytical relations for control actions on four engines that ensure vehicle motion over a prescribed trajectory with desired values of altitude and velocity are derived.     

Precise selective deposition of microparticles on electrodes of microelectronic chips

We examined the high precision deposition of toner and polymer microparticles with a typical size of approximately 10 microm on electrode arrays with electrodes of 100 microm and below using custom-made microelectronic chips. Selective desorption of redundant particles was employed to obtain a given particle pattern from preadsorbed particle layers. Microparticle desorption was regulated by dielectrophoretic attracting forces generated by individual pixel electrodes, tangential detaching forces of an air flow, and adhesion forces on the microchip surface. A theoretical consideration of the acting forces showed that without pixel voltage, the tangential force applied for particle detachment exceeded the particle adhesion force. When the pixel voltage was switched on, however, the sum of attracting forces was larger than the tangential detaching force, which was crucial for desorption efficiency. In our experiments, appropriately large dielectrophoretic forces were achieved by applying high voltages of up to 100 V on the pixel electrodes. In addition, electrode geometries on the chip's surface as well as particle size influenced the desorption quality. We further demonstrated the compatibility of this procedure to complementary metal oxide semiconductor chip technology, which should allow for an easy technical implementation with respect to high-resolution microparticle deposition.     

Autoclave Molding of Thermoprotective Coatings on Large Products Using a Metal composite Mandrel

Russian Engineering Research - Abstract—A technology is developed for the application of a thermoprotective coating by autoclave molding with a metal composite mandrel. This technology...     

A liquid pulsed microwave radiation calorimeter

A wideband calorimeter intended for measuring energies of the pulsed microwave radiation with duration of several nanoseconds to 1 s is described. The calorimeter’s principle of operation is based on measuring the volume increment that results from heating, when the radiation is absorbed by a polar liquid. The energy measurement range is 10 mJ–100 J, the energy-absorption coefficient is >0.9 in a frequency band of 1.6–20 GHz and ～0.99 at frequencies of 4–18 GHz. The measurement error of the absorbed energy in the range 0.2–50 J does not exceed ±4%.     

On the Growth of Thin-Film AlGaN/GaN Epitaxial Heterostructures on Hybrid Substrates Containing Layers of Silicon Carbide and Porous Silicon

Semiconductors - Abstract—In our work, we carry out a structural-spectroscopic study of AlGaN/GaN epitaxial layers grown by molecular-beam epitaxy with nitrogen-plasma activation on a hybrid...     

Cationic Oligomerization of the Pyrolysis C<Subscript>5</Subscript> Fraction

The cationic oligomerization of the pyrolysis C₅ fraction in the presence of catalyst systems based on AlCl₃, VOCl₃, BF₃ · O(C₂H₅)₂, and a Gustavson complex has been investigated. It has been shown that the use of the diisopropyl ether-modified Gustavson complex in the reaction makes it possible to synthesize fully soluble oligomers in high yields. The conversions of all the unsaturated components of the pyrolysis fraction to the oligomer at different durations of the oligomerization process have been determined. The synthesized oligomers are characterized by high unsaturation and exhibit the properties of film-forming compounds.     

Method for detection of ground objects and recognition of their types from radar images of the earth surface

A method for detection of ground objects and recognition of their types against the background of the earth surface from objects’ radar images (RIs) is proposed. The method is based on a priori formation of template RIs of the objects in free space and scanning the RI of the earth surface with two types of rectangular windows. The dimensions of the window of the first type take into account the shadows of the objects, and the dimensions of the windows of the second type take into account only the outer dimensions of the objects. The results of the simulation of the detection characteristics and of the parameters of recognition of a KAMAZ truck and the control station mounted on the same chassis, which were located on a standard earth surface, are presented.     

Ionospheric radio tomography based on the GPS/GLONASS navigation systems

The specific features of the problem of ionospheric radio tomography based on the data from high-orbital navigation systems such as GPS and GLONASS are considered. An approach to solving this problem, which implies finding the solution with the minimum Sobolev’s norm (i.e., the smoothest solution) is proposed. The possibilities of the proposed approach are studied by numerical modeling with the use of real geometry of high-orbital satellite constellation and the layout of the receivers. The modeling shows that the proposed approach is very efficient in the regions with a sufficiently dense network of receivers. The resolution of possible radio tomographic systems over the territory of Russia is estimated. Examples of radiotomographic reconstructions of the ionosphere obtained from real high-orbital satellite data for the European region are presented.     

Formation of silicon nanocrystals in multilayer nanoperiodic <Emphasis Type="Italic">a</Emphasis>-SiO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>/insulator structures from the results of synchrotron investigations

The problem of the efficiency of the controllable formation of arrays of silicon nanoparticles is studied on the basis of detailed investigations of the electronic structure of multilayer nanoperiodic a-SiO _x /SiO₂, a-SiO _x /Аl₂О₃, and a-SiO _x /ZrO₂ compounds. Using synchrotron radiation and the X-ray absorption near edge structure (XANES) spectroscopy technique, a modification is revealed for the investigated structures under the effect of high-temperature annealing at the highest temperature of 1100°C; this modification is attributed to the formation of silicon nanocrystals in the layers of photoluminescent multilayer structures.