Day-time ionospheric disturbances of corpuscular origin in the midlatitudeD-region     

Jan Laštovička  Josef Boška  Reviewer L. Křivský 《Studia Geophysica et Geodaetica》1980,24(2):191-196

¶rt;m uu nau mu m a nu a¶rt;u ¶rt; D-amu u. a¶rt; m nu u u. u¶rt;a a a mu nma u nma mu m (20 ¶rt; 150 ).  相似文献   

An Stratigraphische Hiate gebundene Vererzungen in den Tschechoslowakischen Karpaten     

J. Ilavský 《Mineralium Deposita》1976,11(1):93-110

During the course of the geotectonic development of the West Carpathians there were ore mineralisation periods, which are associated with different stratigraphical hiatuses. Hematite-magnetite ore was deposited in the first period between the Silurian and the Devonian. In both the Middle and the Upper Carboniferous, some stratiform siderite deposits originated, which were exploited in the vicinity of Dobiná and Mlynky during about the last 100 years. In the Permian, some haematite occurrences, fossil gold placers and uranium-bearing strata were formed, the last of which was exploited. Some minor haematite occurrences are widespread in the Lower Triassic. The same type of occurrence is known in the Upper Triassic and in the Lower Jurassic, too. In the Jurassic, small occurrences of manganese ore are known. Bauxite occurreces were found in the Middle and Upper Cretaceous, but they are very small. More important are the sedimentary manganese deposits, which were deposited in the Middle Eocene. These were exploited during the last 70 years. The fossil gold placers of the east Slovakian, Paleogene flysch series are very interesting from genetic point of view. The small kaoline, bauxite and silicate-nickel occurrences, which are associated with the alteration processes of basic rocks of different age, were found during the Miocene. The Quaternary period is well known for its gold placers, from which those of the Danube river as well as others were exploited in the past.

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Nach einem Vortrag gehalten auf der Tagung des Lagerstättenausschusses der G. D. M. B. und der S. G. A. in Clausthal am 4. / 5. April 1975  相似文献   

Approximate expression for the hilbert transform of a certain class of functions and their application to the ray theory of seismic waves     

Vlastislav Červený  Reviewer J. Vaněk 《Studia Geophysica et Geodaetica》1976,20(2):125-132

Summary Approximate expressions for the Hilbert transform of the functionf(t)=exp(- ₀ ² t ²/²) cos( ₀ t+v) are determined. This function, given a suitable choice of the three parameters ₀, and v, approximates a wide class of seismic signals very well. The approximate expressions for the Hilbert transform enable very simple formulae to be given for the elementary seismograms of the individual seismic body waves (in the zero approximation of the ray theory). This accelerates the computation of ray theoretical seismograms considerably.  相似文献   

Velocity-depth function ofP-waves in the region of the central bohemian massif     

Karel Holub  Reviewer J. Janský 《Studia Geophysica et Geodaetica》1974,18(4):390-393

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Spike-like Bursts as Fine Structure of Zebras     

P. Zlobec  M. Karlický 《Solar physics》2007,246(2):419-430

We studied the characteristics of the zebra-associated spike-like bursts that were recorded with high time resolution at 1420 MHz in four intervals (from 12:45 to 12:48 UT) during 5 August 2003. Our detailed analysis is based on the selection of more than 500 such spike-like bursts and it is, at least to our knowledge, the first study devoted to such short-lived bursts. Their characteristics are different from those pertinent to “normal” spike bursts, as presented in the paper by Güdel and Benz (Astron. Astrophys. 231, 202, 1990); in particular, their duration (about 7.4 ms at half power) is shorter, so they should be members of the SSS (super short structures) family (Magdalenić et al., Astrophys. J. 642, L77, 2006). The bursts were generally strongly R-polarized; however, during the decaying part of interval I a low R-polarized and L-polarized bursts were also present. This change of polarization shows a trend that resembles the peculiar form of the zebra lines in the spectral dominion (“V” like). A global statistical analysis on the bursts observed in the two polarimetric channels shows that the highest cross-correlation coefficient (about 0.5) was pertinent to interval I. The zebras and the bursts can be interpreted by the same double plasma resonance process as proposed by Bárta and Karlicky (Astron. Astrophys. 379, 1045, 2001) and Karlicky et al. (Astron. Astrophys. 375, 638, 2001); in particular, the spikes are generated by the interruption of this process by assumed turbulence (density or magnetic field variations). This process should be present in the region close to the reconnection site (e.g., in the plasma reconnection outflows) where the density and the magnetic field vary strongly.  相似文献   

Light-time computations for the BepiColombo Radio Science Experiment     

G. Tommei  A. Milani  D. Vokrouhlický 《Celestial Mechanics and Dynamical Astronomy》2010,107(1-2):285-298

The Radio Science Experiment is one of the on board experiments of the Mercury ESA mission BepiColombo that will be launched in 2014. The goals of the experiment are to determine the gravity field of Mercury and its rotation state, to determine the orbit of Mercury, to constrain the possible theories of gravitation (for example by determining the post-Newtonian parameters), to provide the spacecraft position for geodesy experiments and to contribute to planetary ephemerides improvement. This is possible thanks to a new technology which allows to reach great accuracies in the observables range and range rate; it is well known that a similar level of accuracy requires studying a suitable model taking into account numerous relativistic effects. In this paper we deal with the modelling of the space-time coordinate transformations needed for the light-time computations and the numerical methods adopted to avoid rounding-off errors in such computations.  相似文献   

The model of a flat (Euclidean) expansive homogeneous and isotropic relativistic universe in the light of the general relativity,quantum mechanics,and observations     

Vladimír Skalský 《Astrophysics and Space Science》2010,330(2):373-398

Assuming that the relativistic universe is homogeneous and isotropic, we can unambiguously determine its model and physical properties, which correspond with the Einstein general theory of relativity (and with its two special partial solutions: Einstein special theory of relativity and Newton gravitation theory), quantum mechanics, and observations, too.  相似文献   

Manifestations of the North – South Asymmetry in the Photosphere and in the Green Line Corona     

J. Sýkora  J. Rybák 《Solar physics》2010,261(2):321-335

The north – south asymmetries (NSA) of three solar activity indices are derived and mutually compared over a period of more than five solar cycles (1945 – 2001). A catalogue of the hemispheric sunspot numbers, the data set of the coronal green line brightness developed by us, and the magnetic flux derived from the NSO/KP data (1975 – 2001) are treated separately within the discrete low- and mid-latitude zones (5° – 30°, 35° – 60°). The calculated autocorrelations, cross-correlations, and regressions between the long-term NSA data sets reveal regularities in the solar activity phenomenon. Namely, the appearance of a distinct quasi-biennial oscillation (QBO) is evident in all selected activity indices. Nevertheless, a smooth behavior of QBO is derived only when sufficient temporal averaging is performed over solar cycles. The variation in the significance and periodicity of QBO allows us to conclude that the QBO is not persistent over the whole solar cycle. A similarity in the photospheric and coronal manifestations of the NSA implies that their mutual relation will also show the QBO. A roughly two-year periodicity is actually obtained, but again only after significant averaging over solar cycles. The derived cross-correlations are in fact variable in degree of correlation as well as in changing periodicity. A clear and significant temporal shift of 1 – 2 months in the coronal manifestation of the magnetic flux asymmetry relative to the photospheric manifestation is revealed as a main property of their mutual correlation. This shift can be explained by the delayed large-scale coronal manifestation in responding to the emergence of the magnetic flux in the photosphere. The reliability of the derived results was confirmed by numerical tests performed by selecting different numerical values of the used parameters.  相似文献   

Zinc and sulfur isotope variation in sphalerite from carbonate-hosted zinc deposits,Cantabria, Spain   总被引：2，自引：0，他引：2  

Jan Pašava  Fernando Tornos  Vladislav Chrastný 《Mineralium Deposita》2014,49(7):797-807

We studied zinc and sulfur isotopes and the chemical composition of sphalerite samples from Picos de Europa (Aliva mine) and sphalerite and hydrozincite samples from La Florida mine, two carbonate-hosted Mississippi Valley-type (MVT) deposits located in northern Spain; despite being close, they are hosted in carbonatic rocks of different ages, Lower Carboniferous and Lower Cretaceous, respectively. The two generations of sphalerite at Picos de Europa show different δ⁶⁶Zn values (stage 1 sphalerite +0.24 per mil and stage 2 sphalerite from ?0.75 to +0.08 per mil). Both generations also differ in the sulfur isotope composition (stage 1 has δ³⁴S?=?+6.6 and stage 2 has δ³⁴S?=??0.9 to +2.9 per mil) and the chemical composition (stage 1 sphalerite, compared to stage 2 sphalerite, is significantly enriched in Pb, As, Mn, Sb, slightly enriched in Ag, Ni, and Cu and depleted in Co, Ga, Tl, Te, Ge, and Sn). We suggest that Zn isotope fractionation was controlled predominantly by pH and T changes. High Zn isotope values reflect rapid precipitation of sphalerite from higher-temperature acidic fluids that carried Zn mostly as chloride species after interaction with carbonate rocks while lower Zn isotope values most likely resulted from a longer precipitation process from fluid at higher pH and decreasing T that carried dominantly Zn sulfide species. At La Florida, sphalerite samples show light ⁶⁶Zn-depleted signatures with δ⁶⁶Zn values from ?0.80 to ?0.01 per mil (mostly between ?0.80 and ?0.24 per mil) and δ³⁴S values from +10.7 to +15.7 per mil without any relationship between the δ⁶⁶Zn and δ³⁴S values. Here, the variation in Zn isotope values is interpreted as related to mixing of fluids from two reservoirs. The Zn was carried by a single deep-seated and higher T (~250–320 °C) fluid, and precipitation took place after mixing with a connate S-rich fluid in a system with mH₂S?>?mZn²⁺ as a result of change in pH, T, and Zn predominant species. The light δ⁶⁶Zn accompanied by heavy δ³⁴S values resulted from fractionation of Zn aqueous sulfides at near-neutral pH and decreasing T. Hydrozincite samples show much heavier δ⁶⁶Zn values (+0.21 to +0.33 per mil), consistent with fractionation during supergene processes.  相似文献   

Ccd Photometry of the Neglected Contact Binaries V344 Lac and V1191 Cyg     

Theodor Pribulla  Martin Vaňko  DrahomÍr Chochol  Štefan Parimucha  Daniel Baluďanský 《Astrophysics and Space Science》2005,296(1-4):281-284

New photoelectric and CCD observations of the eclipsing contact binary systems V344 Lac and V1191 Cyg are presented and analyzed. All available times of minimum light were used to study period changes of the systems and determine up-to-date ephemerides. The orbital period of V1191 Cyg is found to be increasing at a very fast rate. The photometric elements were determined using the new light curve, radial-velocity curve and broadening function fitting code ROCHE.  相似文献