N.V. Sennikov1,2, E.V. Lykova1, O.T. Obut1,2, V.N. Tokarev3, A.V. Timokhin1, T.A. Shcherbanenko1, I.G. Zakiryanov1,2 1Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia 2Novosibirsk State University, Novosibirsk, Russia 3AOOT Zapsibgeologiya, Novokuznetsk, Russia
Keywords: Ordovician, biostratigraphy, terrigenous sedimentation, volcanic structures, Salair
Litho- and biostratigraphic analysis of a number of Ordovician reference sections has been completed in five different blocks of Salair, including West-Berd’ (Medvedkovo), East-Berd’, Krasnoe, Gurievsk and Eltsovka. Modern data on nine mainly terrigenous and, less often, carbonate-terrigenous sections bearing fossils and composed of carbonate units and volcanic rocks including lavas, as well as tuff and tuff sandstones have been presented. The Ordovician terrigenous sedimentation in the study area was complicated by stages of volcanic sedimentation. Volcanic-sedimentary sequences were documented at four biostratigraphically dated stages in Salair: 1) the Tremadocian, 2) the late Floian, 3) the middle - late Darriwilian, 4) the late Katian - Hirnantian.
E.G. Vologina1, A.N. Kolesnik2, O.N. Kolesnik2, S.A. Selyutin2 1Institute of the Earth’s Crust, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia 2V.I. Il’ichev Pacific Oceanological Institute, Far Eastern Branch of the Russian Academy of Sciences, Vladivostok, Russia
Keywords: Bottom sediments, rates of recent sedimentation, grain size composition, light- and heavy-fraction minerals, ice rafting, Chukchi Sea
The aim of this work is to elucidate the specifics of recent sedimentation in the Chukchi Sea, based on the study of the material composition of Late Holocene bottom sediments. Analytical methods included grain size and mineralogical analyses. The results of 210Pb and 137Cs dating were used. The sediments are clayey silt and silty clay containing sand admixture and single gravel grains and pebble. The content of coarse-grained material increases slightly in the upper parts of the studied sections. This is probably due to the greater contribution of ice rafting to the recent Chukchi Sea sedimentation as a result of climate warming. The ultrafine- and fine-grained (0.25-0.05 mm) sandy material is dominated by light-fraction minerals. Volcanic glass was discovered in the sediments sampled in the southern and central areas of the Chukchi Sea. It might have been transported from the volcanoes of Alaska, the Aleutian Islands, and the Kamchatka Peninsula through the Bering Strait by the Pacific currents directed from south to north. The sediments collected in the southern, central, and northern areas of the Chukchi Sea differ in grain size and mineral composition. This is probably due to their remoteness from the coastline and provenance areas and is also caused by different rates of sedimentation.
G.Z. Gil’manova1, M.Yu. Nosyrev1, A.N. Didenko1,2 1Kosygin Institute of Tectonics and Geophysics, Far Eastern Branch of the Russian Academy of Sciences, Khabarovsk, Russia 2Geological Institute, Russian Academy of Sciences, Moscow, Russia
Keywords: Digital elevation model, lineaments, gold deposits, metallogeny, Winlessa, ArcGis, North Stanovoi metallogenic zone
A digital elevation model of the North Stanovoi metallogenic zone located in the north of the Stanovoi volcanic-plutonic belt is comprehensively analyzed. The correlation of the calculated parameters with some geological and geophysical characteristics of the territory is shown. Spatial relationships of relief features with the location of gold deposits and ore occurrences in the metallogenic zone are analyzed in detail. Many features are determined that can serve as a basis for identifying potentially gold-bearing regions of the ore cluster rank.
A.V. Malyutina1,2, A.G. Doroshkevich1,3, A.E. Starikova1,2, I.A. Izbrodin1,2, I.R. Prokop’ev1,2, T.A. Radomskaya2,4, M.N. Kruk1,2 1V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia 2Novosibirsk State University, Novosibirsk, Russia 3Dobretsov Geological Institute, Siberian Branch of the Russian Academy of Sciences, Ulan-Ude, Russia 4A.P. Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
Keywords: Alkali syenites, clinopyroxene, amphibole, mica, Burpala massif, Northern Baikal area
Petrographic and mineralogical studies have been carried out for major varieties of rocks composing the Burpalа massif: peralkaline (nepheline), alkali, and quartz syenites. The emphasis was put on the major and trace element composition of mafic minerals present in all types of rocks: clinopyroxenes, micas, and amphiboles. The studies have shown that the compositions of mafic minerals fractionate within each group of rocks but do not form a single trend of evolution in the groups of peralkaline, alkali, and quartz syenites. This suggests the formation of the massif under pulsed intrusion of variably differentiated magma, the contamination of the first portion of magma, and the subsequent formation of quartz syenites.
S.V. Michurin, R.F. Abdrakhmanov, V.N. Durnaeva, V.F. Yuldashbaeva
Institute of Geology of the Ufa Federal Research Center, Russian Academy of Sciences, Ufa, Russia
Keywords: Kungurian Stage, anhydrite, gypsum, celestine, magnesite, southern Cis-Urals
The geochemical and mineralogical features of gypsum of the Kungurian Stage in the southern Cis-Urals have been studied. Elevated contents of Sr (up to 1.6 wt.%) were detected, and its sedimentary genesis has been established. The main Sr-containing mineral in gypsum is сelestine of two generations differing in morphologic features and chemical composition. The presence of early diagenetic celestine in pelitomorphic zones of gypsum is evidence for lagoon sedimentation in the Kungurian. Barium-containing celestine of late generation often develops in assemblage with magnesite in recrystallized zones of gypsum. The weak positive correlations of Sr with Fe, Mg, and К indicate the enrichment of magnesium chloride and calcium-sodium sulfate-chloride brines with these elements during their interaction with rocks, including argillaceous ones, during halocatagenesis. During diagenesis, nodular and microcrystalline pyrite 1 with impurities of Cu, As, Co, and Ni formed. During catagenesis, the recrystallization of gypsum resulted in pure coarse-crystalline pyrite 2. The rocks near the boundary of the Kungurian and Ufimian stages are characterized by elevated Cu contents (up to 283 ppm). The catagenetic celestine is characterized by low Sr/Ba ratios, which, along with the data on the isotopic composition of sulfur of celestine (δ34S = 24.8‰) and with the presence of pyrite inclusions in gypsum, indicate widespread sulfate reduction processes during catagenesis. The increase in the share of 32S in gypsum and anhydrites of the southern Cis-Urals (δ34S = 7.4-13.4‰) is due to the increasing role of continental runoff in the Permian salt basin.
A.I. Gresov, A.V. Yatsuk
V.I. Il’ichev Pacific Oceanological Institute, Far Eastern Branch of the Russian Academy of Sciences, Vladivostok, Russia
Keywords: Bottom sediments, natural gases, isotope-gas geochemical indicators, gas saturation, gas geochemical fields, Laptev-Siberian Sea zone, East Arctic shelf
Gas composition of bottom sediments of the Laptev-Siberian Sea geostructural zone (LSZ) was determined to include: helium and hydrogen in concentrations of 0.0028-0.2092 and 0.0012-0.8727 cm3/kg, hydrogen sulfide - 0.0006-0.0072, carbon monoxide - 0.0016-0.0577, carbon dioxide - 0.1482-21.1602, methane - 0.0017-8.3047 and its homologues (in total) - 0.00001-0.0355 cm3/kg. It was found that the values of average concentrations of gases in bottom sediments increase with the depth of their occurrence and exceed the anomaly criteria identified for the East Arctic shelf by 2.6-27.7 times, including: CO2, CO and H2S - by 2.6, 3.0 and 3.4 times, ΣC2-C5 and He - by 9.3 and 10.8 times, CH4 - by 27.7 times; this actually indicates a high degree of gas saturation of bottom sediments of the region. The formation of CO2, CO, H2S, H2, CH4 and ΣC2-C5 anomalies in sediments of the upper and the base of the middle sampling horizon is determined by relatively high contents of sapropelic and humic organic matter and gas influx from the lower horizon. Distribution of anomalies with maximum concentrations of natural gases and He in sediments of the lower horizon, with minimum contents of Corg, is associated with zones of faults, large dislocations, tectono-magmatic and seismic activity, which are the main routes of diffusion-migration of gas transfer to bottom sediments. Formation of concentrations of gases and their anomalies in sediments of the LSZ follows the rules of additivity, i.e. successive accumulation of migratory natural gases of different genesis with prevalence of gas phase and isotopic indicators of more gas-saturated parental source, epigenetic and syngenetic to sediments. It was found that maximum values of average gas saturation with CH4, ΣС2-С5, He and H2 in LSZ are typical for bottom sediments of the flanks of troughs, CO and CO2 - for the arch parts of uplifts. In sediments of monoclinal folds (structural terraces), minimal values of average gas saturation are observed, with the exception of the South Anyui Fault Zone. In general, gas saturation of LSZ sediments is determined by the complex impact of geological factors, with the major ones being: gas content of rock complexes and gas saturation of underlying sediments, fault and fold tectonics, a high degree of tectono-magmatic and seismic activity, a geostructural position, coal content, oil and gas content, as well as the depth of occurrence, organic saturation and material composition of OM in bottom sediments. The influence of the latter predetermined the formation and distribution of five geochemical fields of CH4, three of CO, ΣС2-С5, He and one of CO2, and one of H2 in LSZ.
D.S. Melnik, T.M. Parfenova
Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: Potential source rock, dispersed organic matter, chemofossils, organic geochemistry, catagenesis, hypergenesis, Vendian, Arctic region, Siberian Platform framing
The results of a geochemical study of rocks and dispersed organic matter (OM) of the middle member of the Vendian Kharayutekh Formation of the Chekurovka Anticline (Kharaulakh anticlinorium of the Verkhoyansk fold-and-thrust belt) close to the Siberian Platform border are presented. Its rocks are found to be unevenly enriched with OM, the maximum present organic carbon content (Corg) reaches 2.6%. The composition and distribution of chemofossils in saturated and aromatic bitumen fractions were studied using gas chromatography and gas chromatography-mass spectrometry. The distributions of alkanes, steranes, terpanes, dibenzothiophenes, and aromatic steroids as well as light isotopic composition of Corg indicate a bacterial-algal origin of OM. Rocks of the middle member of the Kharayutekh Formation originally possessed a high generative potential. Analysis of pyrograms, bitumen characteristics, and the distributions of phenanthrenes and dibenzothiophenes allowed assessing the regional catagenesis of the OM in Vendian deposits in this area corresponding to the early dry gas «window». It was established that the studied bitumens are classified as residual and bare evidence of autochthonous and paraautochthonous origins, with biodegraded hydrocarbons. The study demonstrates the local effect of magmatism on the content and composition of bitumens in the near-contact zone of the section. Intrusion of a thick diabase sill resulted in depletion of generative potential of these rocks in the upper part of the section already in the Cambrian period. The considered information gives us more grounds to assume that accumulations of highly viscous heavy oils and solid bitumens, genetically related to the OM of the middle member of the Kharayutekh Formation, might be expected in the Vendian and Cambrian carbonate and terrigenous reservoirs in the north of the Verkhoyansk Trough. The preservation of gas and gas condensate accumulations is unlikely to be good.
A.A. Dobrynina1,2, V.A. San’kov1,2, S.A. Korol1, N.V. Kichigina3, A.A. Rybchenko1 1Institute of the Earth’s Crust, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia 2Matrosov Institute of System Dynamics and Control Theory, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia 3V.B. Sochava Institute of Geography of the Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
Keywords: Ambient noise, flood, turbulence, precipitation, seismic waves
Variations in ambient seismic noise generated by the Kyngarga river (Tunka Valley) in the calm state and during significantly rising water levels were analyzed, based on the Arshan short-period seismic station data, observations of water level fluctuations at the Kyngarga Rv. hydrological station, and the amount of rainfall measured with precipitation gauge at Peak Lyubvi mountain (Mt). The methods used in the work include the correlation, spectral, spectral-temporal and polarization analyses. Ambient noise vibrations recorded at the Arshan seismic station show instable over time and show significant seasonal variations. During warm periods, the ice cover melting increases the water level in the Kyngarga River, thus causing amplification of seismic vibrations in the frequency range from 2 to 20 Hz. Occurrence of heavy rainfalls and subsequent significant rise in the Kyngarga river water levels (floods) lead to changes in the amplitude-to-frequency response characteristics of ambient seismic noise. This translates into amplification of seismic vibrations in the frequency range from 4 to 20 Hz, with maximum seismic radiation (radiative transfer of seismic waves) in the 6-10 Hz frequency range. For different floods, the amplification varies significantly and depends on the magnitude of the water level rise. Variation of amplitude-frequency characteristics of the ambient seismic noise in summer relative to winter, as well as during floods, is driven by increased water flow turbulence with affiliated increase in water flow velocity and discharge, and sediment dynamics. Diagrams showing particle motion in the medium in a calm state and during floods do not show any dominant orientation of oscillations, which is associated with the length of the source of vibrations whose extent (in this case) is equal to the entire river channel.
O. A. Gorbunov, I. D. Vatnik, D. V. Churkin
Novosibirsk State University, Novosibirsk, Russia
Keywords: fiber lasers, narrow-band generation, cross-phase modulation
The role of the cross-phase modulation between the pump and generation waves in a fiber laser with randomly distributed feedback due to weak Rayleigh backscattering, operating in the ultra-narrow regime, which is observed just above the threshold, is discussed. The spectrum in this case consists of narrow (less than 1 MHz) modes with a typical lifetime of 1 ms. It was demonstrated earlier that both external noises (thermal or acoustic) and the nonlinear process of four-wave interaction between the generation modes can be responsible for the mode decomposition process. In present study, a model of the nonlinear interaction of the pump wave with an ultra-narrow generation mode is constructed, and it is shown that the cross-phase modulation between them can lead to the destruction of the mode if the walk-off is sufficiently slow. It means that the narrow-band generation depends on the fiber dispersion, because the latter determines the corresponding walk-off length. A comparison with experiments confirms this conclusion: in lasers based on fibers with low dispersion, narrow-band generation is not observed, while it does exist in cases with high dispersion coefficients.
P. A. Itrin1, V. A. Ribenek1, Yu. A. Shaman2, A. V. Sysa2, D. A. Korobko1, S. V. Vasin3, A. A. Fotiadi1 1Ulyanovsk State University, Ulyanovsk, Russia 2Scientific-Manufacturing Complex "Technological Centre,", Moscow, Russia 3Ulyanovsk Branch of the Kotelnikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Ulyanovsk, Russia
Keywords: fiber lasers, mode locking, saturable absorber, fiber coupler, fiber taper, carbon nanotubes
A new type of an element providing mode synchronization in a fiber laser source of ultrashort pulses is proposed. This element is a pair of coupled microfiber tapers coated with a layer of carbon nanotubes and combines the functions of a saturable absorber and an output coupler. The proposed version of manufacturing a saturable absorber is technologically simple and can be used in almost any optical laboratory. Based on the manufactured sample of the absorber-coupler and active fibers doped with erbium, a ring fiber laser is manufactured, in which mode synchronization with the generation of picosecond soliton pulses is experimentally demonstrated.
K. V. Proskurina1, M. I. Skvortsov1, E. V. Golikov1, S. R. Abdullina1, A. V. Dostovalov1, O. N. Egorova2, S. L. Semenov2, S. A. Babin1 1Institute of Automation and Electrometry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia 2Prokhorov General Physics Institute, Russian Academy of Sciences, Fiber Optics Research Center, Russian Academy of Sciences, Moscow, Russia
Keywords: single-frequency fiber lasers, fiber Bragg grating, random distributed feedback, erbium fiber
Here we present an erbium fiber laser in a configuration of a half-open cavity formed by a narrow-linewidth fiber Bragg grating and artificial Rayleigh reflector provided random distributed feedback. For additional spectral filtering, a 10-m twin-core fiber wound on a spool with a diameter of 9 cm is used. A single-frequency generation regime with the maximum output power of 4.4 mW is demonstrated, and the generation linewidth is 2 kHz.
V. S. Terentyev, V. A. Simonov
Institute of Automation and Electrometry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: multicladding optical fiber, thin absorbing cladding, mode selection
A new method of transverse mode selection in a cylindrical optical fiber using a thin absorbing cladding is proposed. The results of simulations in the COMSOL ® Multiphysics demonstrate the possibility of selecting the HE12 mode based on the losses in a multimode fiber at a wavelength of 1550 nm, when the thin absorbing cladding (with a thickness of 2.5-10 nm) is located in the vicinity of the minima of the field’s components |Er,φ|. The cladding radius is optimized by the minimum of the linear loss α for a given mode; its value is relatively small and varies from -0.02 to -0.06 dB / cm depending on the cladding parameters, while these values for other modes are greater by a factor of tens. An estimated equation for the linear losses is derived for the analytical description. The optimal radii of the absorbing cladding from the viewpoint of minimizing the losses of the selected mode for various absorption coefficients and cladding thicknesses are investigated. It is shown that the spectral dependence of the linear loss coefficient for a given cladding thickness and absorption coefficient is weak.
D. B. Tretyakov, A. V. Kolyako, A. S. Pleshkov, I. I. Ryabtsev, I. G. Neizvestny
A. V. Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: quantum communication, BB84 protocol, photon polarization coding, single-photon detectors
A method for increasing the quantum key distribution rate in free-space quantum communication lines by simultaneously transmitting single photons with wavelengths of 780 nm and 850 nm through one quantum channel has been proposed and implemented experimentally. Our laboratory system has demonstrated an approximately twofold increase in the "sifted" quantum key distribution rate using two setups operating at wavelengths of 780 nm and 850 nm and transmitting photons through one 23-cm-long quantum channel. The "sifted" quantum key distribution rate and the quantum bit error rate for a wavelength of 780 nm are found to be equal to 11502 ± 290 bits/s and 2.4 ± 0.4%, and the corresponding values for a wavelength of 850 nm are 10627 ± 290 bits/s and 3.9 ± 0.5%.
E. A. Anashkina, A. V. Andrianov
A. V. Gaponov-Grekhov Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia
Keywords: optical microresonator, spontaneous symmetry breaking, cubic nonlinearity, Rayleigh scattering
Spontaneous symmetry breaking in glass dielectric microspheres with the Kerr nonlinearity is studied experimentally and theoretically, taking into account the linear Rayleigh scattering between counterpropagating waves under bidirectional symmetric optical pumping. It is shown that the higher the Rayleigh scattering coefficient, the higher the threshold power required to observe the effect. An increase in the Rayleigh coupling coefficient between counterpropagating waves leads to narrowing of the region of the pump frequency detuning from the exact resonance frequency where spontaneous symmetry breaking is realized and to a decrease in the asymmetry of the light states.
V. P. Bessmeltsev1, S. G. Baev1, N. V. Goloshevsky1, A. V. Lukyanov2, M. D. Jumadilov2 1Institute of Automation and Electrometry, Siberian Bracnh, Russian Academy of Sciences, Novosibirsk, Russia 2JSC «AGFZ,», Barnaul, Russia
Keywords: femtosecond laser modification, laser scanners, hybrid laser scanning system, laser peening and grinding
A method of nanostructural modification of the surface of metal samples previously subjected to heat treatment using femtosecond laser radiation is considered. The results of experiments on the study of the process and determination of technological modes of laser microtreatment (surface peening and laser grinding) are presented. An increase in surface microhardness for hardened workpieces made of tool steels and a subsequent decrease in roughness without loss of hardness are shown.
A. R. Novoselov1, N. N. Mikhailov2, R. V. Menshchikov2, P. A. Aldokhin1, A. E. Matochkin3 1Novosibirsk Branch of the Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, “Technological Design Institute of Applied Microelectronics,”, Novosibirsk, Russia 2Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia 3Institute of Automation and Electrometry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: GaAs, CdTe, ZnTe, instrument plates, a photodetectors of IR radiation
The influence of the formation of thin layers CdTe and ZnTe on the planar side on the shape of GaAs instrument plates has been clarified. In the formation of thin buffer layers of ZnTe (20-300 nm thick) and CdTe (5-7 µm thick), their bending is found to increase by more than 1 µm. A technological solution has been found to reduce the bending of GaAs instrument plates by more than 1 µm after the formation of thin layers (CdTe and ZnTe). After technological annealing at a temperature of 600 °C in high vacuum, the sample slowly cools down (at a rate of 0.5 deg/min) within 11 hours.
A. V. Lapko1,2, V. A. Lapko1,2, A. V. Sharueva2 1Institute of Computational Modelling, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, Russia 2Reshetnev Siberian State University of Science and Technology, Krasnoyarsk, Russia
Keywords: testing the hypothesis of the independence of random variables, pattern recognition, nonparametric estimation of probability density, anthropogenic territories, remote sensing
The results of the application of a new methodology for testing the hypothesis of the independence of random variables in the analysis of remote sensing data of anthropogenic territories are presented. The basis of the technique is a nonparametric pattern recognition algorithm corresponding to the maximum likelihood criterion. Linear and nonlinear dependences between the spectral features that characterize anthropogenic territories are determined. The results of the assessment of anthropogenic territories based on spectral remote sensing data are considered.
A. A. Makeev, V. A. Shcherbachev
JSC “All-Russian Scientific Research Institute «Gradient»,”, Rostov-on-Don, Russia
Keywords: chirp signal, detection, cross-correlation
An algorithm for single pulse chirp signal detection at low signal/noise ratios is proposed. The proposed detection algorithm is based on the cross-correlation of the input chirp pulse and its copy subjected to a frequency shift. As a result of the proposed transformation, a gain in the signal/noise ratio is achieved, which allows the effective use of threshold detection.
A. G. Zlobina1, I. V. Zhurbin1, A. S. Shaura1, E. A. Rubleva1,2 1Udmurt Federal Research Center, Ural Branch, Russian Academy of Sciences, Izhevsk, Russia 2Udmurt State University, Izhevsk, Russia
Keywords: Haralick texture features, image segmentation, thermal imaging, archaeological site, reference data, boundary
The use of thermal imaging for reconstructing historical heritage sites is limited by the influence of modern plowing and the absence of archaeological sites with contrasting thermal properties. A distinctive feature of the proposed statistical analysis algorithm is the use of Haralick texture features at the stage of feature extraction. Subsequent segmentation of the image makes it possible to identify sections of the occupation layer of various capacities as areal landscape objects. The interpretation of their properties is based on the reference data of interdisciplinary research - excavations, geophysics, and soil drilling. An assessment of the trends in the relative locations of segments of different classes and the ratio of their areas allows us to put forward a hypothesis about the boundaries of an archaeological site. At the site of the medieval Kushmanskoe III settlement (Udmurtia), the analysis of the structure of the segmented thermal image reveals fundamental differences in the distribution of the humus layer in the settlement and the adjacent territory, which was not subjected to anthropogenic influence. The proposed algorithm can be considered as an effective tool for studying historical heritage sites.
V. P. Kiryanov, A. V. Kiryanov
Institute of Automation and Electrometry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: built-in angular sensors, systematic error, random error, cross-calibration, laser image generators, test structures, auto-calibration, auto-compensation
The results of testing the effectiveness of using two measurement procedures: self-calibration and auto-compensation are presented. These procedures are used in laser image generators with circular scanning simultaneously to reduce the error in the synthesis structures. It is revealed that, in using such a strategy, it becomes advisable to limit the complexity of the hardware implementation of the self-calibration procedure due to the action of disregarded sources of distortion. To reduce this objectively occurring limit, it is proposed to use an optical-mechanical system configuration in these image generators, similar to what actually occurs when calibrating their angular sensors, as well as continuously monitor and take into account the manifestations of distorting factors whose contributions are unstable over time.
Настоящим выпуском мы открываем очередной том журнала «Оптика атмосферы и океана». Журнал был создан в соответствии с Постановлением Президиума АН СССР № 859 от 15 сентября 1987 г., в котором сказано: «Поручить Институту оптики атмосферы Сибирского отделения АН СССР всю необходимую работу для обеспечения регулярного и своевременного выпуска журнала». Пост главного редактора журнала «Оптика атмосферы» был доверен академику В.Е. Зуеву.
M.V. Tarasenkov, E.S. Poznakharev, A.V. Fedosov, A.N. Kudryavtsev, V.V. Belov
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia
Keywords: water - atmosphere interface, scattered laser radiation, non-line-of-sight optical communication, visible wavelength range, unmanned aerial vehicle
А non-line-of-sight optical communication line with an unmanned aerial vehicle (UAV) through the “water - atmosphere” interface allows removing the limitation of UAV position within the transmitting system divergence angle during communication session. The capabilities of such a communication line were not considered in previous works. The capabilities of a non-line-of-sight optical communication line between an underwater transmission system and an UAV located in the atmosphere are experimentally and theoretically estimated. The field experiments demonstrate the possibility of organizing stable non-line-of-sight optical communication between the underwater transmission system and the UAV at baseline distances of 90 m and UAV flight altitude of 30 m. The simulation of a communication line shows that the useful signal is formed mainly by radiation scattered in the atmosphere in the considered communication scheme at small baseline distances. At large baseline distances, the useful signal is formed by radiation scattered in the water. Therefore, at high water turbidity (visibility depth is 3 m), the useful signal is the highest. The results made it possible to analyze the main patterns in the formation of a useful signal in the communication line under study and are the basis for the creation of such systems.
I.D. Musikhin1, V.V. Kapustin1, A. Movchan1, E.S. Poznakharev2, M.I. Kuryachy1, A.A. Tislenko1, S.A. Zabuga1 1Tomsk State University of Control Systems and Radioelectronics, Tomsk, Russia 2V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia
Keywords: inhomogeneous medium optical radiation propagation, active pulse television measuring system, normalized depth map, retrieval of measuring function form
The paper evaluates the effect of backscattering interference (BI) on the forms of measuring functions of active pulse television measuring systems (AP TMS) in terms of range. Methods for retrieving the shape of the AP TMS range measuring function in translucent media have been developed. To minimize the effect of BI, methods of calculating and subtracting coefficients, as well as a method of removing the constant component of the spectrum are suggested. The proposed methods were tested with 30 experimental video record obtained in a large aerosol chamber (LAC) for two multi-zone range measurement methods and five meteorological media. The best result was achieved when using the method of calculating and subtracting coefficients for video record with the operation of AP TMS in the multi-area range measuring mode (MARMM): the average SD was reduced by 4.5 times.
V.P. Yushkov
Lomonosov Moscow State University, Moscow, Russia
Keywords: turbulence, adiabatic fluctuations, available energy, dissipation rate of sound speed fluctuations
The development of the turbulence theory should be aimed at studying not only incompressible vortices but also the adiabatic component, first of all, pressure and density fluctuations. The intensity of the pressure fluctuations is compared with fluctuations of the potentially available energy of Lagrangian particles. An equation linking the smoothing of entropy fluctuations with the rate of generation of adiabatic fluctuations is proposed. The rate constant of entropy fluctuation smoothing is estimated from measurements in the atmospheric boundary layer. This constant allows us to relate the integral spatial scale of turbulent vortices to the standard deviation of the sound speed fluctuations in the atmospheric boundary layer. Estimates of the adiabatic noise amplitude in the turbulent medium are constructed and the relation between its energy, and the correlation time of the vortex velocity fluctuations is shown.
G.I. Gorchakov1, A.V. Karpov1, R.A. Gushchin1, O.I. Datsenko1, E.G. Semoutnikova2 1A.M. Obukhov Institute of Atmospheric Physics Russian Academy of Sciences, Moscow, Russia 2Lomonosov Moscow State University, Moscow, Russia
Keywords: largescale smoke haze, smoke aerosol, optical characteristic, black carbon, brown carbon, selective absorption, imaginary part of index of refraction, spectral dependence, AERONET
The smoky haze that occurs during massive forest fires radically transforms the radiation regime of the atmosphere over large areas, which is significantly influenced by the variability of the imaginary part of the refractive index of smoke aerosol. The variability of shortwave radiation fluxes in a smoke-laden atmosphere is driven by variations in the optical and microphysical properties of smoke aerosols, including the spectral dependencies of the imaginary part of the refractive index. These dependencies are determined by the presence of black carbon, brown carbon, and radiation-selective absorbing organic compounds in the aerosol particles. This study analyzes the aforementioned spectral dependencies using AERONET data during large-scale wildfires in Alaska in 2019 and Canada in 2023. The analysis includes cases of extreme radiation absorption by black and brown carbon, where the imaginary part of the refractive index at a wavelength of 440 nm reached 0.50 and 0.27, respectively. Variations in the spectral dependence of the imaginary part of the refractive index during moderate manifestations of selective absorption of smoke aerosol during massive fires in Alaska and Canada are analyzed. Approximations for the spectral dependence of the imaginary part of the refractive index are proposed. Estimates of aerosol radiative forcing at the top of the atmosphere are given for extreme manifestations of radiation absorption in the visible and near-infrared spectral regions by black carbon and brown carbon and during anomalous selective absorption. The results indicate a need in the detailed study of large-scale atmospheric smoke.
B.D. Belan1, N.V. Dudorova1, S.N. Kotel’nikov2 1V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia 2Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, Russia
Keywords: O3, ground-level ozone, air pollution, health, morbidity, community-acquired pneumonia
Community-acquired pneumonia is among the most common acute infectious diseases. According to official statistics, pneumonia accounted for up to 50% of respiratory-disease mortality in the Russian Federation in 2005-2017. Ground-level ozone, being a key component of urban smog, is one of little-studied risks of community-acquired pneumonia. This work studies the effect of ground-level ozone on the rate of community-acquired pneumonia among Moscow residents in the warm season over a five-year period (2006-2009 and 2011). The study results have enabled us to conclude that ground-level ozone contributes to an increase in the community-acquired pneumonia rate among Moscow residents in summer. Daily average concentrations of ground-level ozone of 60-80 μg/m3 can increase the community-acquired pneumonia rate by 30% compared to low-ozone periods, especially in combination with unfavorable weather conditions, such as high air temperature and low humidity. The results will help human ecologists and health care professionals to make the urban air safer.
E.G. Kablukova1, V.G. Oshlakov2, S.M. Prigarin1,3 1Institute of Computational Mathematics and Mathematical Geophysics of the Siberian Branch of the RAS, Novosibirsk, Russia 2V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia 3National Research Novosibirsk State University, Novosibirsk, Russia
Keywords: polarized radiation, polarization degree, Stokes parameters, multiple light scattering, Monte Carlo method, laser instrumental navigation system
Algorithms for stochastic simulation of a polarized signal arriving at a photodetector matrix of an aircraft navigation system are developed. The Monte Carlo method is used to estimate angular distributions of Stokes parameters of radiation recorded by the receiver, and the effect of scattering of different order on the total recorded signal and its polarization degree is analyzed. Calculations of the signal intensity using linear polarization filters are performed. The constructed algorithms allow one to estimate the efficiency of the laser navigation system taking into account the polarization of radiation for various meteorological conditions and the possibility of increasing the signal contrast by using polarization filters.
V.A. Korshunov
Federal State Budgetary Institution Research and Production Association Typhoon, Obninsk, Russia
Keywords: stratospheric aerosol, lidar, biomass burning aerosol, brown carbon, aerosol optical model
Biomass burning aerosol has essential effect on radiation properties of the stratosphere. Some known data about this aerosol type are referred to the cases of dense and localized in altitude aerosol layers. Optical properties of it’s background component remain unknown. The processing of two-wavelengths (355 and 532 nm) lidar measurements at Obninsk city in 2012-2023 is fulfilled to determine them. Lidar data interpretation is performed on the basis of two-component model of stratospheric aerosol proposed in this work. Along with the main component (sulfuric acid aerosol), biomass burning aerosol (brown carbon) is considered. As a result, the optical thickness of brown carbon aerosol in 10-30 km layer is estimated at ~ 0.012 and 0.0013 for extinction at 355 and 532 nm and ~ 7.1 × 10-3 и 3.5 × 10-4 for absorption at the same wavelengths. Data presented may be used in the development of advanced radiation models of the stratosphere.
D.A. Marakasov, A.A. Sukharev, R.Sh. Tsvyk
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia
Keywords: supersonic jet, fluctuations, spectrum, sensing laser beam, vortex
A promising method for studying the flow structure in turbulent supersonic jets is the contactless method of laser transillumination. Interpretation of the experimental results is a non-trivial task, especially with respect to turbulence, due to the spatial inhomogeneity of the fields of gas-dynamic characteristics. In this article, the spectral composition of turbulence in axially symmetric jets in the root region (before the closure of the mixing layers) is analyzed based on laser sensing results. The results of experimental studies of intensity fluctuations of a laser beam propagating through a supersonic flooded jet are presented. The spectral fluctuation power density fully corresponds to the known experimental and calculated spectra for a moving turbulent medium, with the exception of the high-frequency interval. The spectrum in this interval is a superposition of two power components, one of which is close to the known value -14/3 and the other is smaller. It is shown that this is due to the difference in motion velocities and the structure of vortex flows in the outer and inner mixing layers. The results can be used in calculating gas-dynamic characteristics and acoustic radiation of jet engines.
O.A. Romanovskii1, S.V. Yakovlev1, S.A. Sadovnikov1, A.A. Nevzorov1, A.V. Nevzorov1, O.V. Kharchenko1, N.S. Kravtsova1, Yu.V. Kistenev1,2 1V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia 2National Research Tomsk State University, Tomsk, Russia
Keywords: lidar, DIAL, greenhouse gas, atmosphere, laser sensing, greenhouse effect
An increase in the level of greenhouse gas concentrations in the atmosphere due to natural and anthropogenic impacts is currently considered a determining factor in climate change and global warming. In this regard, there is an urgent need for the development of new technologies for remote monitoring of greenhouse gases with high spatiotemporal resolution and accuracy, namely laser remote (lidar) systems, which allow, in contrast to standard contact methods of gas analysis, more accurate and informative measurements of concentrations of greenhouse gas components of the atmosphere. The characteristics and description of differential lidars for monitoring methane, carbon dioxide, water vapor, ozone, and other gas components are given. The results of the development of ground-based stationary differential absorption lidar systems for laser remote sensing of the main greenhouse gases in the atmosphere in recent 25 years have been systematized and analyzed. The review of stationary differential absorption lidars for monitoring greenhouse gases in the atmosphere can be useful to specialists in the field of developing systems for remote gas analysis of the atmosphere.
V.V. Ris, A.M. Levchenya, S.A. Galaev, I.A. Ignatiev
Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
Keywords: U-duct, ribbed sides, turbulent flow, heat transfer, numerical modeling, effects of rotation
The paper presents a method and results of simulation for turbulent air flow and heat transfer in a U-shaped square duct with straight sections and with two ribbed opposite sides. For a flow with Reynolds number of 6×104 and Prandtl number of 2.5, the numerical solution method was validated by comparing the calculated and experimental data on local heat and mass transfer in geometrically identical U-ducts; the ribs inclined to the duct axis by 45 and 60 deg. For one of these ducts with the rib inclination angle of 45 deg (at the same Reynolds number and Prandtl number of 0.71), the flow pattern and heat transfer were calculated for a stationary state and for a mode with rotation (with the rotation parameter values of 0.1 and 0.25). The rotation axis is perpendicular to the duct axis and parallel to the duct bended plane. The calculation data for the U-shaped duct are compared with the calculation data for a fully developed (periodic) flow and heat transfer for a straight-and-ribbed duct. It is shown that for a U-duct, the effect of rotation has a positive influence on heat transfer enhancement.
To study the aerodynamics of a pulsating flow in a flat channel of 20×150×600 mm, an experimental setup has been constructed. Gas flow pulsations were generated by rotating a damper that completely blocked the channel. The damper was located behind the test section, and the setup operated in the regime of sucking air from the surrounding space. These studies were carried out using the PIV method, synchronizing the measuring system with the damper rotation angle. The experiments were carried out at pulsation frequency F = 8 Hz. The experimental results are directly compared with the case of a steady flow with a fixed damper, but with the same rotation angle as in the case of phase averaging. It has been established that under these conditions, superimposed flow pulsations weakly affect the longitudinal velocity profiles, integral characteristics of the wall layer and friction coefficient, which indicates a quasi-steady flow in the channel.
A pioneering study of the influence of longitudinal slots (grooves) with different depths h (corresponding to the Reynolds numbers Reh = 900 and 1300) on the stability of a supersonic (Mach number М = 2) boundary layer on a flat plate to controlled disturbances of the first (vortex) mode of instability determining the laminar-turbulent transition at М = 2 is performed. At the Reynolds numbers Re h = 900 and 1300, the growth rates of three-dimensional disturbances at the frequency ƒ = 14 kHz are found to be smaller than the corresponding value for the smooth plate. Thus, it is shown that controlled disturbances of the first mode can be stabilized by longitudinally aligned slots with a small depth (Reh < 1500).
The synthesis of diamond coatings on silicon substrates using a gas-jet method, which uses a high-speed jet to transport a gas mixture activated in a microwave discharge, is studied. The coatings are synthesized from a mixture of hydrogen, methane and argon. The possibility of maintaining the integrity of the silicon substrate under conditions of gas-jet deposition at high temperatures is shown. The rate of diamond synthesis on a silicon substrate exceeded the one, achieved earlier in gas-jet experiments with activation in microwave plasma without adding argon, as well as during deposition from a hydrogen-methane-argon mixture at lower substrate temperatures.
Data on the structure of seeding a flow in a supersonic wind tunnel with electric arc heating of the test gas by particles are reported. Velocity profiles near the plate surface are obtained. It is shown that the spectral characteristics of particle seeding inhomogeneity depends on the Reynolds number and flow regime. The possibility of identifying the anisotropic component of the particle distribution inhomogeneity field in the laminar boundary layer on the plate is demonstrated.
A simple CFD modeling method is presented adapted for problem of liquid spraying by a centrifugal nozzle. The method is based on the VOF method and several assumptions; this approach enables calculating the spraying characteristics during a reasonable computation time. The primary testing results confirmed the possibility of using this simulation method.
Results of experimental measurements of aerodynamic forces acting on a finite-size cylindrical body in a compressible flow are reported. The flow around a transversely aligned cylinder and the influence of yaw angle variation in the interval β = 0 - 9° are studied. For each position of the cylinder, several locations of the blowing hole along the cylinder radius are considered. The force measurements are performed with the use of strain gauges. The changes in the drag force, lift force, yaw moment, and roll moment are investigated. New experimental data are obtained in the study on the influence of blowing on changes in aerodynamic cha-racteristics of the finite-size cylindrical body in a compressible flow. The data are analyzed and interpreted.
D.V. Kosenkov, V.V. Sagadeev
Kazan National Research Technological University, Kazan, Russia
Keywords: elements of the IV period, emissivity, atomic number, correlation, coefficient of thermal expansion, coefficient of sur-face tension
The results of correlating the emissivity of pure metals in the liquid phase with the atomic number of the element in the periodic system and the properties, which include the coefficients of thermal expansion and surface tension, are presented. The results obtained fit the periodic system. The emissivity has a periodicity with traceable translational properties.
S.O. Morozov
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
Keywords: compressible boundary layer, theory of linear stability, Görtler vortex, direct numerical simulation
The effect of light gas injection on the linear stage of Görtler vortex development in a compressible boundary layer was studied. The problem is solved in the framework of linear stability theory and using the direct numerical simulation for Navier-Stokes equations. The data on the vortex growth and vortex profiles are in agreement for these two methods. It was demonstrated that helium injection into a compressible boundary layer upon a convex surface can reduce the growth rate for Görtler vortices.
A lattice model of the pore space of a microsphere packing and a method for calculating the microstructure of a two-phase flow, taking into account the topology of pores, are proposed. The sequence of filling the pore constrictions and expansions with drainage and impregnation phases and the dependence of capillary pressure on saturation of phases and the coefficient of longitudinal dispersion for transfer of a dissolved substance were obtained under conditions of the determining influence of capillary forces.
