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761.
J. Sylwester I. Gaicki Z. Kordylewski M. Kowaliński S. Nowak S. Płocieniak M. Siarkowski B. Sylwester W. Trzebiński J. Bakała J. L. Culhane M. Whyndham R. D. Bentley P. R. Guttridge K. J. H. Phillips J. Lang C. M. Brown G. A. Doschek V. D. Kuznetsov V. N. Oraevsky A. I. Stepanov D. V. Lisin 《Solar physics》2005,226(1):45-72
We describe the RESIK (REntgenovsky Spektrometr s Izognutymi Kristalami) instrument, consisting of two double-channel X-ray spectrometers, designed to observe solar active region and flare plasmas. RESIK is one of the instruments making up the scientific payload of the Russian CORONAS-F solar mission. The uncollimated spectrometer uses two silicon and two quartz bent crystals observing flare, active region and coronal spectra in four wavelength bands with a resolving power (/ ) of 1000. The wavelength coverage, 3.3–6.1 Å, includes emission lines of Si, S, Cl, Ar, and K and in the third diffraction order, the wavelength range includes He-like Fe lines (1.85 Å) and Ni lines (1.55 Å) with dielectronic satellites, emitted during intense, hot flares. The instrument is believed to be the best calibrated space-borne crystal spectrometer flown to date. The spectrometer dynamically adjusts the data gathering intervals from 1 s to 5 minutes, depending on the level of solar X-ray emission at the time of observation. The principal aims of RESIK are the measurements of relative and absolute element abundances in the emitting plasma and the temperature distribution of plasma (differential emission measure) over the temperature interval 3 and 50 MK. This paper summarizes the scientific objectives of RESIK and describes the design, characteristics, and performance of the instrument. 相似文献
762.
763.
764.
Stanisław Bellert 《Astrophysics and Space Science》1970,7(2):211-230
The paper is an extension of this author's hypothesis, presented inAstrophys. Space Sci.
3 (1969), 268, which explains the red shift in terms of a geometry of static space and stationary observers. The author introduces here the notions of metric with an observer, observed distance and space of observations; he considers the problem of the equivalence of stationary observers and discusses the relation between the hypothesis, the special theory of relativity and Maxwell equations. Attention is drawn to the agreement between the hypothesis and the experimental results discussed by Shamir and Fox, and those discussed by Kennedy and Thorndike. 相似文献
765.
Sławomir Breiter 《Celestial Mechanics and Dynamical Astronomy》2001,81(1-2):81-91
Lunisolar resonances arise in the artificial satellite problem without short-periodic terms. The basic model including the Earth's J
2and a Hill-type model for the Sun or the Moon admits 20 different periodic terms which may lead to a resonance involving the satellite's perigee, node and the longitude of the perturbing body. Some of the resonances have been studied separately since 1960s. The present paper reviews all single resonances, attaching an appropriate fundamental model to each case. Only a part of resonances match known fundamental models. An extended fundamental model is proposed to account for some complicated phenomena. Most of the double resonance cases still remain unexplored. 相似文献
766.
Witold Szczuciński Przemysław Niedzielski Grzegorz Rachlewicz Tadeusz Sobczyński Anetta Zioła Artur Kowalski Stanisław Lorenc Jerzy Siepak 《Environmental Geology》2005,49(2):321-331
Tsunami sediments deposited in a coastal zone of Thailand by the 26 December 2004 tsunami wave were sampled within 50 days after the event. All surface and ground waters in tsunami- inundated zone revealed significant salinity at that time. The tsunami sediments, composed mainly of fine to medium sand, contain significantly elevated contents of salts (Na+, K+, Ca+2, Mg+2, Cl and SO
4
−2
) in water-soluble fraction, and of Cd, Cu, Zn, Pb in the bioavailable fraction and As in the exchangeable fraction in relation to the reference sample. The origin of contaminants is marine, as well as litho- and anthropogenic. The salts and Pb, Zn and Cu reveal high correlation to each other and to the mean grain size (pore size and porosity). Serious environmental hazard exists in that region because, due to gentle morphology, there is a risk of migration of the contaminants into ground waters and food chain. 相似文献
767.
Herman W. J. Kernkamp Henri A. H. Petit Herman Gerritsen Erik D. de Goede 《Ocean Dynamics》2005,55(3-4):351-369
In this paper, the formulations of the primitive equations for shallow water flow in various horizontal co-ordinate systems
and the associated finite difference grid options used in shallow water flow modelling are reviewed. It is observed that horizontal
co-ordinate transformations do not affect the chosen co-ordinate system and representation in the vertical, and are the same
for the three- and two-dimensional cases. A systematic derivation of the equations in tensor notation is presented, resulting
in a unified formulation for the shallow water equations that covers all orthogonal horizontal grid types of practical interest.
This includes spherical curvilinear orthogonal co-ordinate systems on the globe. Computational efficiency can be achieved
in a single computer code. Furthermore, a single numerical algorithmic code implementation satisfies. All co-ordinate system
specific metrics are determined as part of a computer-aided model grid design, which supports all four orthogonal grid types.
Existing intuitive grid design and visual interpretation is conserved by appropriate conformal mappings, which conserve spherical
orthogonality in planar representation. A spherical curvilinear co-ordinate solution of wind driven steady channel flow applying
a strongly distorted grid is shown to give good agreement with a regular spherical co-ordinate model approach and the solution
based on a β-plane approximation. Especially designed spherical curvilinear boundary fitted model grids are shown for typhoon
surge propagation in the South China Sea and for ocean-driven flows through Malacca Straits. By using spherical curvilinear
grids the number of grid points in these single model grid applications is reduced by a factor of 50–100 in comparison with
regular spherical grids that have the same horizontal resolution in the area of interest. The spherical curvilinear approach
combines the advantages of the various grid approaches, while the overall computational effort remains acceptable for very
large model domains. 相似文献
768.
Monika Agnieszka Kusiak Artur Kdzior Mariusz Paszkowski Kazuhiro Suzuki Ignacio Gonzlez-lvarez Bolesaw Wajsprych Marek Doktor 《Lithos》2006,88(1-4):56-71
This paper reports the results of CHIME (chemical Th–U–Pb isochron method) dating of detrital monazites from Carboniferous sandstones in the Upper Silesia Coal Basin (USCB). A total of 4739 spots on 863 monazite grains were analyzed from samples of sandstone derived from six stratigraphic units in the sedimentary sequence. Age distributions were identified in detrital monazites from the USCB sequence and correlated with specific dated domains in potential source areas. Most monazites in all samples yielded ca. 300–320 Ma (Variscan) ages; however, eo-Variscan, Caledonian and Cadomian ages were also obtained. The predominant ages are comparable to reported ages of certain tectonostratigraphic domains in the polyorogenic Bohemian Massif (BM), which suggests that various crystalline lithologies in the BM were the dominant sources of USCB sediments. 相似文献
769.
Sławomir Maj 《Physics and Chemistry of Minerals》1984,10(3):133-136
The Gladstone-Dale law (specific refraction) and the Drude law (molecular refraction) for silica polymorphs, at “sodium light” (λ D =0.5893 μm), are derived from simple atomic properties of SiO2 complex (atomic weight, first ionization potential). The considerations are based on the Lorentz electron theory of solids. The characteristic frequency (or eigenfrequency) v 0 of elementary electron oscillators (in energy units, hv) is identified with the band gap E G of a solid; on the other hand, this E G -gap is identified with the single ionization potential \(\tilde U\) of non-free atoms. For \(\tilde U\) =E G =10.2 eV (energy gap of quartz, see Nitsan and Shankland 1976b) the Gladstone-Dale law, or specific refraction, is (n?1)/ρ=0.208 cm3/g, where n and ρ are the refractive index and the density of medium, respectively. According to empirical data, the average value of the specific refraction of pure SiO2 polymorphs (except stishovite-high density phase of silica) is (〈n〉?1)/ρ=0.207±0.001 (〈n〉 denotes the mean refractive index of crystal). For stishovite the Drude law (n 2?1)/ρ=0.542 cm3/g is valid under an assumption that the first ionization potential \(\tilde U\) =E G ≈9 eV; this result is good agreement with the empirical value (〈n〉2?1)/ρ=0.536 cm3/g. 相似文献
770.
The dynamic response of hyperboloidal shells on discrete column supports is studied using a curved rotational shell finite element. In this finite element formulation, the displacement field over each element domain is approximated by polynomial functions in which the coefficients of the linear terms correspond to the nodal values of the displacements and the higher order terms vanish at the nodal circles. The stiffness and mass matrices associated with the equations of motion are derived from Hamilton's variational principle and include the effects of transverse shearing deformation and rotatory inertia. Since the formulation, as such, involves a great many degrees of freedom because of the use of higher order displacement functions, the kinematic condensation technique is employed to reduce the order of the dynamic problem The dynamic analysis indicates the importance of realistically modelling the base region of the shell. Studies on a prototype tower indicates that the base flexibility reduces the natural frequencies of the shell and increases the displacements near the base. The magnitude of this reduction, which could be significant, depends primarily on the tangential stiffnesses of the supporting columns and is hardly affected by the thickened ring beam at the base. 相似文献