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1.
The analysis of the kinematic properties of the Galactic thick disk based on data from modern catalogs of stellar radial velocities and proper motions is presented. A new aspect of new determination of the kinematic characteristics of the thick disk is that the selected objects define this disk’s properties near the plane of symmetry. The velocity dispersion of stars in the Galactic thick disk in the radial direction and the direction of the Galactic rotation have been determined. The stellar-velocity distribution in the direction of the rotation is asymmetric. The parameters of this asymmetry have been determined, and the lag of the rotational velocity of the thick disk relative to objects in the thin disk estimated. The value of this “asymmetric drift,” about 20 km/s, suggests larger spatial scales for the kinematic characteristics in the radial direction for the Galactic thick disk than for the thin disk.  相似文献   

2.
二调中MapGIS数据到ArcGIS数据转换问题的研究   总被引:1,自引:0,他引:1  
葛琴 《安徽地质》2012,(3):223-225
目前,应用比较广泛的两种地理信息系统软件MapGIS软件和ArcGIS软件,都各自占有很大的地理信息市场.但它们的各自都拥有自己的数据格式.一直以来地矿部门所采用GIS软件基本上是MapGIS软件,随着ArcGIS软件在我国各领域应用逐渐广泛,这就需要我们将目前拥有的大量MapGIS格式的GIS数据转换成ArcGIS数据.因此在资源有效利用驱使下,迫切需要实现这两种数据格式的共享.本文深入讨论了实现GIS软件之间数据格式转换的各种方法,并描述了由MapGIS格式数据转换为ArcGIS格式数据的详细过程.通过转换过程分析这种转换模式存在的问题,并提出解决问题的方法.  相似文献   

3.
The transitional Alpine-Iranian and North African-Apulian zones, which extend between the North Eurasian, Arabian, and African lithospheric plates, are composed largely of crustal blocks bounded by seismically active faults and, as follows from the data of satellite geodesy, are characterized by the variously directed present-day motions of these blocks. The measured horizontal displacements of the largest blocks in the ITRF system are compared with motions of the main lithospheric plates suggested by the NNR-NUVEL-1A model. The established discrepancies are related to the deformation of blocks in the transitional zones between interacting plates, a circumstance that is consistent with relative block displacements. The close coincidence of the measured and the model velocities of horizontal motions at observation points in western Europe beyond the alps allows us to extend the North Eurasian Plate to the west of the Rhine Grabens. The systems of intraplate active faults are considered, and the depth of that surface, along which tectonic blocks move in the horizontal direction, is estimated.  相似文献   

4.
Results of centimeter-wavelength RATAN-600 observations of several hundred NVSS objects with a wide range of flux densities are presented. Changes in spectral-index distributions from strong-to faint-object populations are estimated. In the transition from strong to faint radio sources, the number of steep-and ultrasteep-spectrum objects decreases and the minimum between steep-and flat-spectrum objects, which was first discovered in the 1970s, becomes less distinct. A less certain increase in the fraction of inverted-spectrum objects is also found. Comparison with theoretical models of radio-source evolution suggests that the decrease in the number of steep-and ultrasteep-spectrum objects can be naturally explained by a sharp decrease in the fraction of classical FRII radio galaxies. The decrease in the sharpness of the minimum may be due to the growing contribution from the population with spectral indices 0.7–0.5, which is usually identified with starbust galaxies. The small increase in the fraction of inverted-spectrum radio sources can be attributed to the growing number of objects with active nuclei. Our spectrum-based conclusions are confirmed by the morphology of the FIRST Catalog images. The number of radio sources associated with supermassive black holes in the Early Universe is estimated using data from the SDSS Catalog.  相似文献   

5.
The results of field structural studies of the Tuapse shear zone in the Northwest Caucasus are presented. This zone is characterized by shear displacements of various scales with a dominant horizontal shear, viz., a geodynamic type of the stress state, which leads to the formation of faults with mostly lateral displacement of wings, i.e., along the strike of the fault surface. The quantitative characteristics of the local stress conditions in the shear zone (the positions of principal axes and the Lode–Nadai coefficient) are determined on the basis of cataclastic analysis and geological indicators of the paleostresses. The differences between these characteristics are considered for the large tectonic zones. Significant spatial (areal) variations in orientations of the axes of major normal stresses in the shear zone and their local weak gentle variations are evidence of a consistent general stress direction during the formation of faults during the Late Eocene–Miocene deformation epoch.  相似文献   

6.
When gravity survey accuracies of a few microgals are sought, many correction factors must be accounted for, including meter calibration constants, water-table level fluctations, solid-earth tides, ocean tides and in some cases rapid atmospheric fluctuations. Calculation of most of these correction factors is relatively straightforward. However, the effects of ocean tide loading are not as easily estimated, partly due to the lack of knowledge of the ocean tides themselves. Amplitude and phase factors for the better-known ocean tide components O1 and M2 have been theoretically computed for a grid in southern California in order to correct gravity survey data at arbitrary locations for these ocean tidal-loading components. The gravity data from a three-month period were recorded on a tidal gravimeter at the station PAS and then hand-digitized in order to test the ocean tide estimation program. The O1 and M2 ocean tidal components were effectively reduced to less than 0.5 μGal. The remaining high-frequency tidal components appear to be K1 and S2. If the ocean tides are not taken into account, as much as 16–20 μGal of error can occur solely due to the effect of ocean loading on the gravitational tides when comparing two surveys near Pasadena. The effect increases towards the coastline and decreases inland. Examples of reduced data from the CIT gravity survey network, which has been observed on an approximately monthly basis since 1974, will be shown.  相似文献   

7.
Riverine water and sediment discharge to the Arctic Ocean is among the most important parameters influencing Arctic climate. It is clear that the evaluation of Arctic paleoclimate requires information on the paleodischarge of major rivers entering the sedimentation basin. Presently, the water discharge of the Ob River accounts for about 12% of the total input of river water into the Arctic Ocean. During the investigation of the Kara Sea in the framework of the Russian-German SIRRO Project, the history of Yenisei discharge received much attention in a number of publications. This paper presents the results of lithological and geochemical investigations with application to the Holocene discharge of the Ob River. Qualitative (SiO2, Al2O3, K2O, and some modules) and quantitative (sedimentation rates and absolute masses of sedimentary material) parameters were used to characterize the history of the Ob sediment discharge. It was shown that the investigated paleochannels of the Ob were initiated at the Pleistocene-Holocene boundary, and during the first half of the Holocene, the river discharge decreased irregularly with decreasing age of sediments. The observed maxima are in fairly good agreement with the data for the Yenisei. We proposed a hypothesis on the influence of glacioisostatic movements in the marginal region of the former Kara ice sheet of late Valdai age on the cessation of marine-fluvial glaciation in the paleochannels of Ob and Yenisei in the periphery of the Ob-Yenisei shoal.  相似文献   

8.
9.
A new approach to diagnostics of the preseismogenic state of the lithosphere within the focal area was considered by the example of spectral analysis of the monitoring data on ice cover deformations in Lake Baikal.  相似文献   

10.
Molecular and supermolecular structures of fossilized resins from the North Eurasia have been studied in detail by IR-spectroscopy, atomic force microscopy (AFM), scanning (SEM), and high-resolution transmission electron (HRTEM) microscopy. The analysis of the IR-spectroscopy data allowed to identify the types of the fossil resins (succinite, rumanite, retinite, etc.). In the succinites and rumanite, the supermolecular structure was observed by AFM. Sizes of the supermolecular particles are 50–120 nm. Some chain-like and cluster-like aggregates can be observed when globules contact with each other. Using SEM and HRTEM techniques, it has been shown that mineral impurities are mainly located as scattered inclusions (from one nanometers up to several tens micrometers in size) in an amorphous organic matrix of the resin.  相似文献   

11.
Cosmogenic radionuclides with distinctive half-lives from chondritic falls were used as natural detectors of galactic cosmic rays (GCR). A unique series of uniform data was obtained for variations in the integral gradients of GCR with a rigidity of R > 0.5 GV in 1955–2000 on heliocentric distances of 1.5–3.3 AU and heliographic latitudes between 23° S and 16° N. Correlation analysis was performed for the variations in GCR gradients and variations in solar activity (number of sunspots, SS, and intensity of the green coronal line, GCL), the intensity of the interplanetary magnetic field (IMF), and the inclination of the heliospheric current sheet (HCS). Distribution and variations of GCR were analyzed in 11-year solar cycles and during a change in 22-year magnetic cycles. The detected dependencies of GCR gradients on the intensity of IMF and HCS inclination provided insight into the differences in the processes of structural transformation of IMF during changes between various phases of solar and magnetic cycles. The investigated relationships lead to the conclusion that a change of secular solar cycles occurred during solar cycle 20; moreover, there is probably still an increase in the 600-year solar cycle, which can be among the major reasons for the observed global warming.  相似文献   

12.
The stress state of the sedimentary rocks in the oil-and-gas fields of Sakhalin is estimated and analyzed; data from exploratory boreholes in the eastern Pacific (San-Andreas fault zone) are considered. The vertical and limiting horizontal stresses are calculated for different depths. The maximum sublateral compression can exceed the vertical stress by a factor of 1.2–4 on average in northern and southern Sakhalin. It is shown that the limiting horizontal stress and the maximum shear stress grow as the depth increases.  相似文献   

13.
We have analyzed the spatial distribution of galaxies from the latest release of the Sloan Digital Sky Survey of galactic redshifts (SDSS DR7), applying the complete correlation function (conditional density), two-point conditional density (cylinder), and radial density methods. Our analysis demonstrates that the conditional density has a power-law form for scales lengths 0.5–30 Mpc/h, with the power-law corresponding to the fractal dimension D = 2.2 ± 0.2; for scale lengths in excess of 30 Mpc/h, it enters an essentially flat regime, as is expected for a uniform distribution of galaxies. However, in the analysis applying the cylinder method, the power-law character with D = 2.0 ± 0.3 persists to scale lengths of 70 Mpc/h. The radial density method reveals inhomogeneities in the spatial distribution of galaxies on scales of 200 Mpc/h with a density contrast of two, confirming that translation invariance is violated in the distribution of galaxies to 300 Mpc/h, with the sampling depth of the SDSS galaxies being 600 Mpc/h.  相似文献   

14.
Studies of the extreme solar proton event of January 20, 2005 intensified the contest over of a long-standing problem: are solar cosmic rays arriving at the Earth accelerated by solar flares or by shocks preceding rapidly moving coronal mass ejections? Among the most important questions is the relationship between the energy spectra of the solar cosmic rays and the frequency spectra of flare microwave bursts. Some studies of previous solar-activity cycles have shown that such a relationship does exist, in particular, for protons with energies of tens of MeV. The present work analyzes this relation using data for 1987–2008. For flare events observed in the western half of the disk, there is a significant correlation between the index δ, which is equivalent to the power-law index of the integrated energy spectrum of 10–100 MeV protons detected near the Earth’s orbit, and radio burst parameters such as a ratio of peak fluxes S at two frequencies (for example, at 9 and 15 GHz) and a microwave peak frequency f m . Proton fluxes with hard (flat) energy spectra (δ ≤ 1.5) correspond to hard microwave frequency spectra (S 9/S 15 ≤ 1 and f m ≥ 15 GHz), while flares with soft radio spectra (S 9/S 15 ≥ 1.5 and f m ≤ 5 GHz) result in proton fluxes with soft (steep) energy spectra (δ ≥ 1.5–2). It is also shown that powerful high-frequency bursts with the hardest radio spectra (f m ≈ 30 GHz) can point at acceleration of significant proton fluxes in flares occurring in strong magnetic fields. These results argue that solar cosmic rays (or at least their initial impulses) are mainly accelerated in flares associated with impulsive and post-eruptive energy release, rather than in shocks driven by coronal mass ejections.  相似文献   

15.
During the Last Glacial, a very open vegetation existed over western Europe, the tundra-like vegetation in The Netherlands evolving into a stcppic-like vegetation towards the Mediterranean. This model was used to analyse the correlation of the Praetiglian (dated from 2.3 to 2.1 million years ago) in northern Europe with the earliest steppic phase in the Mediterranean region. On this basis, stratigraphic relationships between these two areas are postulated for the whole Pliocene and the Early Pleistocene in terms of the vcgctational changes related to the climatic fluctuations. For the first time, correlation has been shown between the palynostratigraphy of northern Europe and the Late Neogcnc marine stratigraphy of the Mediterranean region; moreover, chronological confirmation is supplied by the mammal zonation. the evolution of stratiotes, palaeomagnetic measurements, and K/Ar dates. The conventional Plio-Pleistocenc boundary occurs during the first interglacial (Tiglian) of northern Europe.  相似文献   

16.
The release kinetics of Xe of the isotopically normal component of noble gases (P3 component) from the coarse-grained fraction of nanodiamonds from the Orgueil (CI) meteorite and the kinetics of 4He release from lunar soil were studied by means of a numerical simulation. It is demonstrated that the release of these gases as a peak with a single pronounced maximum may not correspond to the diffusion model with a single activation energy and can in fact be controlled by a spectrum of activation energies with a number of peaks a number of peaks remaining unresolved at stepped pyrolysis. In particular, the amount of Xe-P3 preserved in nanodiamonds during thermal metamorphism of the Orgueil meteorite calculated using parameters of the diffusion process (activation energy and frequency factor) that were determined in the model with a single activation energy indicates that practically all Xe should be lost during a very short time. These losses are inconsistent with both the duration of thermal metamorphism of the meteorite parent bodies and the Xe-P3 concentrations measured in these meteorites. A much higher preservation of Xe-P3 during thermal metamorphism lasting for hundreds of years follows from calculations based on diffusion with a spectrum of activation energiesa for Xe release. The results of isothermal pyrolysis of a nanodiamonds fraction from Orgueil confirms a presence of several activation energies for Xe-P3 release from the nanodiamonds. The application of the diffusion model with a spectrum of activation energies to He release from lunar soil samples also shows that He can be retained in these samples at 20°C during a much longer time than it follows from the model with a single activation energy (Anufriev, 2010).  相似文献   

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19.
Data from the Nobeyama Radioheliograph at 17 GHz with high spatial and temporal resolution are used to detect quasi-periodic pulsations with periods from 55 to 250 s in the thermal component of the microwave emission of a solar flare loop observed on June 2, 2007. Observed pulsations with periods of about 110–120 s are co-phased along the entire loop axis. The observed periodicity is most likely due to modulation of the radio emission by slow magnetoacoustic waves trapped in the filamentary flare loop.  相似文献   

20.
We have obtained continuous latitude distributions of the K and F corona brightnesses at various distances for the first time, using both the Hayes—Vourlidas—Howard method and our own recently proposed, simple technique for separating the emission of the K and F coronas. Data from the LASCO C2 and C3 coronagraphs are analyzed. Variations of the angular size of the brightness distribution of the F corona with latitude and distance are estimated, as well as the ratio of the maximum F-corona brightness to the F-corona brightness at the pole. The variations in the F-corona brightness at large distances (R = 25 R , where R is the solar radius) are studied on various time scales—a month, a year, and 11 years (the solar cycle). The latitude distribution of the F-corona brightness varies most appreciably over a year, and only weakly over one solar revolution and one solar-activity cycle (as considered on a fixed day of the year).  相似文献   

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