北京市延庆县红果寺炼镁用白云岩矿床地质特征及意义     

王德利  李长伟 《城市地质》1997,9(2):22-28

红果寺炼镁用白去是北京地区普查评价的第二个炼镁用白云岩矿床。矿体呈层状，单斜构造，赋存于雾迷山组三段地层中，出露较高，位于侵蚀基准面之上，适于露采。该矿的发现法区在北京地区此类矿产的勘查和白云岩的深层次开发利用，具一定意义。  相似文献   

A statistical analysis of methanol maser groups     

I. E. Val’tts  S. Yu. Lyubchenko 《Astronomy Reports》2004,48(10):834-839

An analysis of the flux densities of the 5₁-6₀ A ⁺ (6.7 GHz) and 2₀-3_?1 E (12.2 GHz) class II methanol maser lines in a large and homogeneous sample of maser sources has been carried out. For convenience, the maser lines were divided into three groups: group I contains spectral features for the lines most prominent in the 5₁-6₀ A ⁺ (6.7 GHz) transition, group II contains spectral features for the lines strongest in the 2₀-3_?1 E (12.2 GHz) transition, group III contains spectral features for which the velocities of the emission maxima of the two lines coincide. The same dependence was found for group II and group III: log S _6.7=(0.79±0.05)×log S _12.2+(0.79±0.05). The spectral features in group I do not obey this relation, and deviations from a linear dependence are considerably greater. It is suggested that methanol class II masers be divided into a subclass IIa, which has special conditions favoring 6.7 GHz masers, and a subclass IIb, which is comprised of the 12.2 GHz masers and those 6.7 GHz masers that necessarily accompany them under the same conditions.  相似文献   

Relative variations of the physical parameters of variable extragalactic radio sources     

S. A. Tyul’bashev  P. A. Chernikov 《Astronomy Reports》2004,48(9):716-723

A method for studying the physical conditions in compact components of extragalactic radio sources displaying variability on time scales of hundreds of days is proposed. The method can be used to estimate the relative variations of the magnetic-field strength and number density of relativistic electrons in superluminal jets from the cores of quasars and radio galaxies. Results are presented for the jets of the quasars 3C 120, 3C 273, 3C 279, and 3C 345. The energies of the magnetic field and relativistic particles in these objects are not in equipartition. As a rule, the magnetic-field strength decreases appreciably during the evolution of an expanding jet, while the number of relativistic electrons grows.  相似文献   

Dissipationless disk accretion     

S. V. Bogovalov  S. R. Kel’ner 《Astronomy Reports》2005,49(1):57-70

We consider disk accretion resulting purely from the loss of angular momentum due to the outflow of plasma from a magnetized disk. In this limiting case, the dissipation due to the viscosity and finite electrical conductivity of the plasma can be neglected. We have obtained self-consistent, self-similar solutions for dissipationless disk accretion. Such accretion may result in the formation of objects whose bolometric luminosities are lower than the flux of kinetic energy in the ejected material.  相似文献   

Visual extinction towards the Omega Nebula (M17) and the ionization of nitrogen in the nebula     

Yu. I. Glushkov  V. F. Esipov  L. N. Kondrat’eva 《Astronomy Reports》2005,49(1):36-43

We estimate the absolute intensity of the Hα emission line in M17 based on spectroscopic observations with the 70 cm telescope of the Fesenkov Astrophysical Institute and the 1.25 m telescope of the Sternberg Astronomical Institute’s Crimean Laboratory. The visual extinction, A _v , is derived for about 250 regions in the nebula via a comparison of the optical (Hα) and radio (21 cm continuum) emissions. The A _v values for the eastern, optically bright, part of the nebula are 2–6^m. For the western part, which is covered by a dark cloud, the extinction is A _v = 7?14.5^m. We derived I(Hα)/I([NII] λ6584) ratios and estimated the degree of ionization of nitrogen in the nebula; we find that most nitrogen is in the [NIII] state.  相似文献   

The role of socio-environmental networking in the sustainability of rain-fed agriculture in the coastal savanna of Ghana     

Michael O’Neal Campbell 《GeoJournal》2005,61(1):79-88

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Thermal anomalies on Savich Cone,Kikhpinych Volcano,Kamchatka: IR surveys and land-based observations for 30 years (1982 through 2012)     

O. F. Kardanova  I. K. Dubrovskaya  Ya. D. Murav’ev 《Journal of Volcanology and Seismology》2015,9(6):368-377

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Modeling a Shore Profile Formed by Storm Cycle Impact     

Leont’yev  I. O. 《Oceanology》2018,58(6):892-899

Oceanology - A model is developed for predicting the sand shore profile formed by storm event impact. The model takes into account the cumulative effect of elementary processes responsible for...  相似文献   

Long-term variability of UV radiation in the spectral range of 300–380 nm in Moscow     

E. I. Nezval’  N. E. Chubarova 《Russian Meteorology and Hydrology》2017,42(11):693-699

The seasonal and interannual variability of global ultraviolet (UV) radiation in the spectral range of 300-380 nm (0380) in Moscow in 1968-2014 is analyzed. The effect of cloudiness on the magnitude of 0380 is assessed. The smallest (-22...-26%) losses due to cloudiness are registered in May-August, and the highest ones (to -45%) are observed in October-November. According to the UV radiation reconstruction model and measurement data, the long-term deviations of 0380 from the average (for 1968-1997) due to clouds can reach + (11-12)%. The statistically significant positive linear trend in total annual 0380 is revealed from the data of both the reconstruction model and observations (about 1.5% per decade for 1968-2014 and 3% per decade for 1979-2014).  相似文献   

Gas mixing with aqueous solution in the ore-forming hydrothermal process: an example of gold     

V. Yu. Prokof’ev  N. N. Akinfiev  S. L. Selektor 《Geochemistry International》2016,54(5):403-414

The mixing of gas and aqueous fluid in hydrothermal ore-forming processes is discussed with reference to gold deposits to demonstrate that this phenomenon may affect ore deposition. Data on fluid inclusions in samples from the Sukhoi Log and Olimpiadinskoe deposits in Russia are utilized to demonstrate possible implications of gas mixing with hydrothermal solution when gold ores are formed. A simplified thermodynamic model is suggested to show how interaction between aqueous saline solutions with pure carbon dioxide or carbon dioxide—methane mixture may affect gold solubility. Further studying such processes may provide interesting information for understanding the genesis of ore mineralization.  相似文献