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V. A. Nikishin N. A. Malyshev A. M. Nikishin D. Yu. Golovanov V. F. Proskurnin A. V. Soloviev R. F. Kulemin E. S. Morgunova G. V. Ulyanov P. A. Fokin 《Doklady Earth Sciences》2017,473(2):402-405
New data on the ages of detrital zircons from folded basement rocks and cover sediments of the Severnaya Zemlya archipelago and Izvestiy TSIK islands have been obtained. The basement age is defined as Cambrian (pre-Ordovician). The Ordovician and Silurian sandstones were mainly formed by erosion of the basement rocks. The Devonian sandstones were formed by debris sourced from the Caledonian orogen. The Carboniferous–Early Permian molasse was formed simultaneously with the erosion of the Carboniferous granitoids and weathering of the Ordovician volcanic arc rocks and the Cambrian basement. The North Kara basin was formed in the Ordovician as a back-arc basin. It experienced its main compression deformations at the boundary of the Devonian and Carboniferous and in the Carboniferous. 相似文献
2.
Moiseev A. V. Maskaev M. V. Ulyanov D. K. Sokolov S. D. Belyatsky B. V. 《Doklady Earth Sciences》2021,499(1):564-569
Doklady Earth Sciences - New results on the study of the geochemical and Sr–Nd isotopic compositions of effusive and explosive rocks of the Oxfordian–Kimmeridgian Kulpolnei complex and... 相似文献
3.
An ultra-low-noise input amplifier intended for a use in a radio telescope operating at 91 cm wavelength is presented. The amplifier noise temperatures are 12.8?±?1.5 and 10.0?±?1.5?K at ambient temperatures of 293 and 263?K respectively. The amplifier does not require cryogenic cooling. It can be quickly put in operation thus shortening losses in the telescope observation time. High linearity of the amplifier (output power at 1 dB gain compression P1dB?≥?22 dBm, output third order intercept point OIP3?≥?37 dBm) enables the telescope operation in highly urbanized and industrialized regions. To obtain low noise characteristics along with high linearity, high-electron-mobility field-effect transistors were used in parallel in the circuit developed. The transistors used in the amplifier are cost-effective and commercially available. The circuit solution is recommended for similar devices working in ultra-high frequency band. 相似文献
4.
S. V. Kuzin S. V. Shestov S. A. Bogachev A. A. Pertsov A. S. Ulyanov A. A. Reva 《Solar System Research》2011,45(2):174-181
In January 2009, the CORONAS-PHOTON spacecraft was successfully launched. It includes a set of telescopes and spectroheliometers—TESIS—designed
to image the solar corona in soft X-ray and EUV spectral ranges. Due to features of the reading system, to obtain physical
information from these images, it is necessary to preprocess them, i.e., to remove the background, correct the white field,
level, and clean. The paper discusses the algorithms and software developed and used for the preprocessing of images. 相似文献
5.
S. V. Kuzin I. A. Zhitnik S. V. Shestov S. A. Bogachev O. I. Bugaenko A. P. Ignat’ev A. A. Pertsov A. S. Ulyanov A. A. Reva V. A. Slemzin N. K. Sukhodrev Yu. S. Ivanov L. A. Goncharov A. V. Mitrofanov S. G. Popov T. A. Shergina V. A. Solov’ev S. N. Oparin A. M. Zykov 《Solar System Research》2011,45(2):162-173
On February 26, 2009, the first data was obtained in the TESIS experiment on the research of the solar corona using imaging spectroscopy. The TESIS is a part of the scientific equipment of the CORONAS-PHO-TON spacecraft and is designed for imaging the solar corona in soft X-ray and extreme ultraviolet regions of the spectrum with high spatial, spectral, and temporal resolutions at altitudes from the transition region to three solar radii. The article describes the main characteristics of the instrumentation, management features, and operation modes. 相似文献
6.
Abstract— We have made Be‐B measurements in six calcium‐aluminum‐rich inclusions (CAIs) (mostly type B inclusions) from CV chondrites and compared them to Al‐Mg measurements. All CAIs show 10B excesses in melilite that are correlated with Be/B ratios. The initial 10Be/9Be ratio inferred from the correlation line is 6.2 times 10?4. In contrast to the Be‐B system in melilite, the Al‐Mg system in anorthite is disturbed. This is probably due to B diffusion in melilite being slow compared with Mg diffusion in anorthite. This suggests that Be‐B chronology may be useful for measuring time differences of high‐temperature (melting, condensation, etc.) events in the early solar system. 相似文献
7.
Five-second observations of the solar corona carried out in the FeIX 171 Å line by the KORONAS-FOTON instrument TESIS are used to study the dynamics of small-scale coronal structures emitting in and around coronal bright points. The small-scale structures of the lower corona display complex dynamics similar to those of magnetic loops located at higher levels of the solar corona. Numerous detected oscillating structures with sizes below 10 000 km display oscillation periods from 50 to 350 s. The period distributions of these structures are different for P < 150 s and P > 150 s, which implies that different oscillation modes are excited at different periods. The small-scale structures generate numerous flare-like events with energies 1024–1026 erg (nanoflares) and with a spatial density of one event per arcsecond or more observed over an area of 4 × 1011 km2. Nanoflares are not associated with coronal bright points, and almost uniformly cover the solar disk in the observation region. The ejections of solar material from the coronal bright points demonstrate velocities of 80–110 km/s. 相似文献
8.
Anton Reva Artem Ulyanov Alexey Kirichenko Sergey Bogachev Sergey Kuzin 《Solar physics》2018,293(10):140
Nanoflare-heating theory predicts steady hot-plasma emission in non-flaring active regions. It is hard to find this emission with conventional non-monochromatic imagers (such as the Atmospheric Imaging Assembly or the X-Ray Telescope), because their images contain a cool-temperature background. In this work, we search for hot plasma in non-flaring active regions using the Mg?xii spectroheliograph onboard the Complex Orbital Observations Near-Earth of Activity on the Sun (CORONAS)-F/SPectroheliographIc X-ray Imaging Telescope (SPIRIT). This instrument acquired monochromatic images of the solar corona in the Mg?xii 8.42 Å line, which emits only at temperatures higher than 4 MK. The Mg?xii images only contain the signal from hot plasma, without any low-temperature background. We studied the hot plasma in active regions using SPIRIT data from 18?–?28 February 2002. During this period, the Mg?xii spectroheliograph worked with a 105-second cadence almost without data gaps. Hot plasma was observed only in the flaring active regions. We did not observe any hot plasma in non-flaring active regions. The hot-plasma column emission measure in the non-flaring active region is not expected to exceed \(3 \times10^{24}\) cm?5. The hot differential emission measure is lower than 0.01% of the DEM of the main temperature component. The absence of Mg?xii emission in the non-flaring active regions can be explained by weak and frequent nanoflares (with a delay of less than 500 seconds) or by very short and intense nanoflares that lead to non-equilibrium ionization. 相似文献
9.
Alexander N. Krot Marina A. Ivanova Alexander A. Ulyanov 《Chemie der Erde / Geochemistry》2007,67(4):283-300
The recently discovered metal-rich carbonaceous chondrite Isheyevo consists of Fe, Ni-metal grains, chondrules, heavily hydrated matrix lumps and rare refractory inclusions. It contains several lithologies with mineralogical characteristics intermediate between the CH and CB carbonaceous chondrites; the contacts between the lithologies are often gradual. Here we report the mineralogy and petrography of chondrules in the metal-rich (70 vol%) and metal-poor (20 vol%) lithologies. The chondrules show large variations in textures [cryptocrystalline, skeletal olivine, barred olivine, porphyritic olivine, porphyritic olivine-pyroxene, porphyritic pyroxene], mineralogy and bulk chemistry (magnesian, ferrous, aluminum-rich, silica-rich). The porphyritic magnesian (Type I) and ferrous (Type II) chondrules, as well as silica- and Al-rich plagioclase-bearing chondrules are texturally and mineralogically similar to those in other chondrite groups and probably formed by melting of mineralogically diverse precursor materials. We note, however, that in contrast to porphyritic chondrules in other chondrite groups, those in Isheyevo show little evidence for multiple melting events; e.g., relict grains are rare and igneous rims or independent compound chondrules have not been found. The magnesian cryptocrystalline and skeletal olivine chondrules are chemically and mineralogically similar to those in the CH and CB carbonaceous chondrites Hammadah al Hamra 237, Queen Alexandra Range 94411 (QUE94411) and MacAlpine Hills 02675 (MAC02675), possibly indicating a common origin from a vapor–melt plume produced by a giant impact between planetary embryos; the interchondrule metal grains, many of which are chemically zoned, probably formed during the same event. The magnesian cryptocrystalline chondrules have olivine–pyroxene normative compositions and are generally highly depleted in Ca, Al, Ti, Mn and Na; they occasionally occur inside chemically zoned Fe, Ni-metal grains. The skeletal olivine chondrules consist of skeletal forsteritic olivine grains overgrown by Al-rich (up to 20 wt% Al2O3) low-Ca and high-Ca pyroxene, and interstitial anorthite-rich mesostasis. Since chondrules with such characteristics are absent in ordinary, enstatite and other carbonaceous chondrite groups, the impact-related chondrule-forming mechanism could be unique for the CH and CB chondrites. We conclude that Isheyevo and probably other CH chondrites contain chondrules of several generations, which may have formed at different times, places and by different mechanisms, and subsequently accreted together with the heavily hydrated matrix lumps and refractory inclusions into a CH parent body. Short-lived isotope chronology, oxygen isotope and trace element studies of the Isheyevo chondrules can provide a possible test of this hypothesis. 相似文献
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A. Yu. Lein Yu. A. Bogdanov V. V. Maslennikov Syaoli Li N. V. Ulyanova S. P. Maslennikova A. A. Ulyanov 《Lithology and Mineral Resources》2010,45(4):305-323
Mineralogy and geochemistry of the sulfide-bearing rocks and ores discovered in the Menez Gwen field are studied. Samples
were taken during the expedition of the Shirshov Institute of Oceanology (cruise 49, R/V Akademik Mstislav Keldysh. The mineral composition of rocks and ores were studied by the traditional methods of optical microscopy, scanning electron
microscopy (CAMSCAN), and microprobe analysis (EPMA SX-50). Contents of trace elements were determined by the laser ablation
inductively coupled plasma-mass spectrometry (LA-ICP-MS). The Zn-Cu ore comprises zonal sulfide chimney intergrowths. Numerous
Se-rich copper ore fragments occur in the volcanomictic layered gritstones and/or barite slabs. The mineral composition, zonality,
and association of trace elements in ore are typical of “black smokers” formed at the basalt base near the Azores Triple Junction
in the MAR. The results obtained make it possible to reconstruct formation history of the Menez Gwen hydrothermal field into
the high-temperature (Cu-Se association in ore clasts), medium-temperature (Zn-Cu-As association in ore), and recent (Ba-SiO2 association) stages. 相似文献
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