排序方式: 共有91条查询结果,搜索用时 15 毫秒
11.
Gorchakov G. I. Kopeikin V. M. Karpov A. V. Gushchin R. A. Datsenko O. I. Buntov D. V. 《Doklady Earth Sciences》2022,505(1):483-488
Doklady Earth Sciences - Using the measurement data in a wind–sand flux on the desertified areas of Astrakhan oblast and Kalmykia, it has been established that the time variability of... 相似文献
12.
Vera K. Rosenbush Vasilij G. Shevchenko Alexander V. Sergeev Feodor P. Velichko Nikolai V. Karpov 《Icarus》2009,201(2):655-665
We present new polarimetric and photometric observations of high-albedo E-type Asteroid 44 Nysa in the BVRI wavebands at phase angles ranging from 0.41° to 7.49° during the 2005 opposition. A bimodal phase-angle dependence of polarization was found for Nysa in the V band. The polarization opposition effect was revealed in the form of a secondary minimum of negative polarization with amplitude ∼0.3% centered at a phase angle ∼0.8°. It is superimposed on the regular negative polarization branch with minimal polarization −0.30% at a phase angle 5.8°. We analyzed all available polarimetric data for E-type Asteroids 44 Nysa, 64 Angelina, and 214 Ashera and confirmed the presence of the polarization opposition effect for high-albedo asteroids at phase angle ∼1° with an amplitude ∼0.35%. The magnitude-phase curves reveal the presence of spike-like opposition effect of brightness for 44 Nysa in the BVRI spectral bands. 44 Nysa is the second high-albedo asteroid after 64 Angelina for which both the polarization opposition effect and the brightness opposition effect are detected. The differences between the parameters of the opposition effects for silicate surfaces (44 Nysa, 64 Angelina, Io) and icy surfaces (Europa, Ganymede, Iapetus, Saturn's rings) are discussed. The specific morphological parameters of opposition effects, in particular the angular width of the polarization opposition effect is comparable to that of the brightness opposition effect, provide almost unequivocal evidence that they are caused by coherent backscattering. One of unexpected results of our investigation is that 44 Nysa becomes bluer with increasing phase angle, while 64 Angelina shows phase reddening. 相似文献
13.
The publication of large photometric surveys and the tools for the cross-identification of their objects open up a possibility
for obtaining multicolor photometry of hundreds of millions of objects. This, in turn, makes it possible not only to classify
the objects and determine their parameters, but also to measure the interstellar extinction towards them and produce an extinction
map for the Milky Way. The aim of this study is to develop a tool for the cross identification of objects in the most well-known
surveys and test it in several sky areas. To this end, we implemented an algorithm of fast positional matching of large astronomical
catalogs in small (up to one degree) sized areas with filtering of false identification. As a result, we drew in seven 0.1-degree
radius areas samples of objects from the DENIS, 2MASS, SDSS, GALEX, and UKIDSS surveys, and performed the cross-identification
of these surveys. We compiled the corresponding subcatalogs in the VO Table format. The tool developed as a result of this
work can be used to cross-identify objects in arbitrary sky areas for the further classification and determination of stellar
parameters, including the measurement of the amount of interstellar extinction. 相似文献
14.
A. G. Nikolaeva G. A. Karpov A. Yu. Bychkov 《Journal of Volcanology and Seismology》2018,12(2):109-127
This study considers variations in the physical and chemical characteristics of water in Lake Karymskii for the period from January 1996, when a phreatomagmatic eruption occurred in the lake, until 2015. Our monitoring revealed two characteristic sets of components whose behavior characterizes the hydrochemical evolution of lake water: a comparatively rapid exponential decay of the concentrations of SO4, Ca, and Mg and a slow decrease in the concentrations of Cl, Na, and K. We arrived at the conclusion that two components of the fluid flow (a fumarolic and a hydrothermal component proper) simultaneously occurred during the eruption and thus had an effect on the lake water. We adduce evidence to show that the water balance and the chemical composition of Lake Karymskii stabilized toward 2015. 相似文献
15.
V. I. Silaev G. A. Karpov L. P. Anikin V. N. Filippov V. A. Petrovsky A. E. Sukharev Yu. S. Simakova 《Doklady Earth Sciences》2017,476(1):1048-1053
The results of X-ray structural, electron-microscopic, and X-ray spectral microprobe studies of Al-based metal solid solutions that underwent nuclear disintegration and that were discovered in nature for the first time are presented. Based on the similarity to technical counterparts, it is suggested to recognize the previously unknown alloys as natural duralumin. 相似文献
16.
17.
Sources of modern hydrothermal systems are considered on the basis of high-precision REE data on representative samples of characteristic hydrochemical types of hydrothermal systems of the Eastern Volcanic Belt of Kamchatka and data available on modern magmatogenic fluid systems of the Kamchatka, Kuriles, and oceanic rift zones. It was found that modern high-temperature chloride-sodium hydrothermal vents have elevated REE contents and that all considered hydrochemical types of the Kamchatka hydrothermal systems are characterized by similar REE patterns. High REE contents in the hydrothermal vents with pH up to 5.0 show bimodal distribution. Correlations established between La/Yb ratios in the hydrothermal vents of various types and in the igneous rocks of the Eastern Volcanic Belt of Kamchatka are interpreted in genetic terms. A positive correlation was found between rare-earth elements, chlorine and boron contents. It was noted that all considered hydrochemical types show distinct negative europium anomaly, whereas submarine hydrothermal vents of oceanic rift zones are characterized by positive europium anomaly. It was proposed that REE was transported in the hydrothermal vents from apical zones of deep-seated magma chambers containing acid derivatives. 相似文献
18.
19.
G. Beskin S. Bondar S. Karpov V. Plokhotnichenko A. Guarnieri C. Bartolini D. Greco A. Piccioni 《Astrophysical Bulletin》2010,65(3):286-295
We discuss the search strategy of fast optical transients accompanying gamma-ray bursts in wide-field monitoring. We describe
the instrumentation and methods of observational data reduction, allowing to detect optical flashes brighter than 10–11 stellar
magnitudes with temporal resolution of 0.13 s. The prospects of both instrument engineering, as well as development of techniques
to search and investigate optical transients of various nature in wide fields are also discussed. 相似文献
20.