Fermi-LAT has made a significant contribution to the study of high-energy gamma-ray diffuse emission and the observation of ∼3000 discrete sources. However, one third of all gamma-ray sources (both ...galactic and extragalactic) are unidentified, the data on the diffuse gamma-ray emission should be clarified, and signatures of dark matter particles in the high-energy gamma-ray range are not observed up to now. GAMMA-400, currently developing gamma-ray telescope, will have the angular (∼0.01° at 100 GeV) and energy (∼1% at 100 GeV) resolutions in the energy range of 10-1000 GeV better than the Fermi-LAT (as well as ground gamma-ray telescopes) by a factor of 5-10 and observe some regions of the Universe (such as Galactic Center, Fermi Bubbles, Crab, Cygnus, etc.) in the highly elliptic orbit (without shading the telescope by the Earth) continuously for a long time. It will permit to identify many discrete sources, to clarify the structure of extended sources, to specify the data on the diffuse emission, and to resolve gamma rays from dark matter particles.
Registered events identification procedures details in three apertures of gamma-telescope GAMMA-400 are discussed in the presented article for gammas, electrons/positrons and protons both in low and ...high energy bands. Gamma-telescope GAMMA-400 consists of the converter-tracker (C) surrounded by anticoincidence system, time-of-flight system (2 sections S1 and S2) and calorimeter. Anticoincidence system will make of top and lateral sections - ACtop and AClat, time-of-flight system TOF contain 2 segments S1 and S2. Calorimeter consists of position-sensitive calorimeter CC1 makes of 2 strips layers and 2 layers of CsI(Tl) detectors and electromagnetic calorimeter CC2 composed of CsI(Tl) crystals surrounded by plastic lateral detectors LD. Scintillation detectors of the calorimeter S3 and S4 placed correspondingly between CC1 and CC2 and after electromagnetic calorimeter. All segments of detector systems ACtop, AClat, S1-S4, LD composed of two BC-408 based sensitive layers thickness of 1 cm each. Events registration both from upper and lateral directions provides due three apertures: main, additional and lateral. GAMMA-400 parameters are optimized for detection of gamma-quanta with the energy ∼ 100 GeV in the main aperture. Gammas, electrons/positrons and protons recognition in main aperture provides due energy deposition analysis in individual detectors of ACtop, AClat, S1-S3 and CC1 individual scintillator detectors discriminators. Particles identification in the additional aperture supplied by study of energy deposition in the individual detectors S2, S3 and position-sensitive calorimeter individual scintillator detectors discriminators. In the lateral aperture low energy (0.2 - 100 MeV) photons classified by using simple anticoincidence signals from the individual detectors of LD and CC2. Higher energies γ-quanta (E>100 MeV) recognized using energy deposition analysis in the individual detectors of S3, S4, LD and CC2.
An analysis of the state of equipment of 72 outdated coal HPP (heat power plants) of a total capacity 14.3 GW with steam parameters before the turbines
p
before
≤ 9 MPa,
t
before
= 420–540°С was ...performed. The equipment is characterized by a considerably low efficiency factor, even if it were converted to burning the natural gas, and by increased release of harmful substances. However, on the most part of the considered HPP, the steam turbines, unlike the boilers, have thus far retained the operation applicability and satisfactory reliability of performance. The analysis has shown that it makes sense to effectively modernize the outdated coal HPP by transformation of their equipment into combined-cycle plant (CCP) with coal gasification, which has high economic and ecological indicators due to thermodynamic advantage of the combined cycle and simpler purification of the generator gas in the process under pressure. As the most rational way of this transformation, the one was recognized wherein—instead of the existing boiler (boilers) or parallel to it—a gasification and gas turbine system is installed with a boiler-utilizer (BU), from which steam is fed to the HPP main steam pipe. In doing this, the basic part of the power station equipment persists. In the world, this kind of reconstruction of steam power equipment is applied widely and successfully, but it is by use of natural gas for the most part. It is reasonable to use the technology developed at Heat Engineering Research Institute (HERI) of hearth-steam gasification of coal and high-temperature purification of the generator gas. The basic scheme and measures on implementation of this method for modernization of outdated coal HPP is creation of CCP with blast-furnace of coal on the basis of accessible and preserved HPP equipment. CCP power is 120 MW, input-output ratio (roughly) 44%, emissions of hazardous substances are 5 mg/МJ dust, 20–60 mg/МJ SO
2
, and 50–100 mg/МJ NO
х
. A considerable decrease of specific CCP cost is expected: down to approximately half compared to that of CCP with coal gasification created elsewhere abroad. Verification and debugging of accepted solutions can be carried out at a small-scale pilot plant.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The GAMMA-400 gamma-ray space-based telescope has as its main goals to measure cosmic γ-ray fluxes and the electron-positron cosmic-ray component produced, theoretically, in dark-matter-particles ...decay or annihilation processes, to search for discrete γ-ray sources and study them in detail, to examine the energy spectra of diffuse γ-rays - both galactic and extragalactic - and to study gamma-ray bursts (GRBs) and γ-rays from the active Sun. Scientific goals of GAMMA-400 telescope require fine angular resolution. The telescope is of a pair-production type. In the converter-tracker, the incident gamma-ray photon converts into electron-positron pair in the tungsten layer and then the tracks are detected by silicon- strip position-sensitive detectors. Multiple scattering processes become a significant obstacle in the incident-gamma direction reconstruction for energies below several gigaelectronvolts. The method of utilising this process to improve the resolution is proposed in the presented work.
A relatively new original concept of metabolic immunity is described based on long-term original clinical studies and confirmations from clinical testing. Multiple sclerosis (MS) and cerebrovascular ...disorders (CVDs) are a pressing problem, while their etiology is not completely understood, especially in the former case, and most likely involves many factors. However, metabolic immunity, which is associated with cell–tissue clusters of the body and providing a key link in the inseparable chain of systemic and local immunity, is a basic principle. Basic markers of the main bodily reactions and their relationships and the results of testing various immune preparations are reported. Various types of immune responses were identified, and a severity rating of laboratory changes in particular nosological forms was developed as a tool for effective immunotherapy.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Scattering of surface acoustic waves (SAWs) in a reflective delay line, which is a Y+128°-cut lithium niobate substrate with aluminum interdigital transducers and reflecting structures located on its ...surface, is investigated by the finite-element method. The effects of scattering of SAW RF pulses by various surface irregularities are investigated in order to determine the topological parameters that minimize the loss of the SAW energy caused by the bulk-mode radiation into the substrate. The dependences of the energy coefficients of reflection and absorption of SAW RF pulses on the height and width of the reflecting irregularities whose dimensions are comparable to a wavelength have been determined.
The GAMMA-400 gamma-ray telescope is designed to measure the gamma-ray fluxes in the energy range from ∼20 MeV to ∼1 TeV, performing a sensitive search for high-energy gamma-ray emission when ...annihilating or decaying dark matter particles. Such measurements will be also associated with the following scientific goals: searching for new and studying known Galactic and extragalactic discrete high-energy gamma-ray sources (supernova remnants, pulsars, accreting objects, microquasars, active galactic nuclei, blazars, quasars). It will be possible to study their structure with high angular resolution and measuring their energy spectra and luminosity with high-energy resolution; identify discrete gamma-ray sources with known sources in other energy ranges. The major advantage of the GAMMA-400 instrument is excellent angular and energy resolutions for gamma rays above 10 GeV. The gamma-ray telescope angular and energy resolutions for the main aperture at 100-GeV gamma rays are ∼0.01% and ∼1%, respectively. The motivation of presented results is to improve physical characteristics of the GAMMA-400 gamma-ray telescope in the energy range of ∼20-100 MeV, most unexplored range today. Such observations are crucial today for a number of high-priority problems faced by modern astrophysics and fundamental physics, including the origin of chemical elements and cosmic rays, the nature of dark matter, and the applicability range of the fundamental laws of physics. To improve the reconstruction accuracy of incident angle for low-energy gamma rays the special analysis of topology of pair-conversion events in thin layers of converter performed. Choosing the pair-conversion events with more precise vertical localization allows us to obtain significantly better angular resolution in comparison with previous and current space and ground-based experiments. For 50-MeV gamma rays the GAMMA-400 gamma-ray telescope angular resolution is better than 50.
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•PEO mode for restoration of protective properties of TO-coating was developed.•Formation of composite coating improves protective properties of restored coating.•Formed ...polymer-containing layers have antifriction properties.•Composite coatings have high hydrophobic properties.
The process of plasma electrolytic oxidation (PEO) and subsequent fluoropolymer treatment of VT1-0 commercially pure titanium with thermal oxide on the surface has been developed to restore the protective coating, integrity of which was destroyed as a result of long-continued operation. The composition and morphology of coatings before and after restoration have been studied by optical microscopy, SEM, optical laser profilomery, XRD, and EDS analyses. The electrochemical behavior of coatings, as well as bare titanium has been investigated using potentiodynamic polarization tests, EIS, and 7-days immersion in 3% NaCl solution. Additionally, microhardness and wear resistance of the samples have been studied. Coatings wettability has been evaluated by sessile drop method. It has been found that composite layers consist of rutile, anatase and PTFE. It has been established that the formation of composite coating on samples with PEO-layers using polytetrafluoroethylene (PTFE) reduces corrosion current threefold in comparison with the coating obtained using the thermal treatment followed by PEO. Moreover, PEO-coating has shown high corrosion resistance during long-term exposure to 3% NaCl solution. Formed composite surface layer has antifriction properties and reduce wear threefold in comparison with the thermal coating. Composite coating are highly hydrophobic: the contact angle attains 152°.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Studying high-energy (>50GeV) cosmic gamma radiation raises a problem of selection of neutral gamma rays from a background of charged particles. The problem is embarrassed by the backsplash effect. ...The backsplash consists, in the main, of low-energy (1 MeV) secondary photons moving backwards and is produced by any high-energy gamma quantum. A charged-particle rejection method using the anticoincidence and time-of-flight systems is proposed. Charged-particle events are distinguished from those being triggered by high-energy gamma-rays producing backsplash. The method is based on the time separation of signals. It allows us to keep the gamma-ray detection efficiency high up to high energies.
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