Possibilities of GPS Kinematic Measurements for Geological Survey in East Slovakia     

Vladimir  Sedlak  Viera  Hurcikova 《地球空间信息科学学报》2002,5(4):21-25

This paper deals with transformation procedures for observed GPS data from the world geodetic system WGS-84 into the national geodetic grid datum S-UTCN(system of united trigonometric cadaster network) and Baa(the Baltic Sea after adjustment).Transformation from WGS-84 into SUTCN is performed most frequently by means of the 7-element Helmert transformation with three identical points.Geodetic network was adjusted by two ways.  相似文献   

Robustness analysis of geodetic horizontal networks   总被引：2，自引：1，他引：2  

P. Vaníček  M. R. Craymer  E. J. Krakiwsky 《Journal of Geodesy》2001,75(4):199-209

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Effects of the spherical terrain on gravity and the geoid   总被引：3，自引：0，他引：3  

P. Novák  P. Vaníček  Z. Martinec  M. Véronneau 《Journal of Geodesy》2001,75(9-10):491-504

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Application of the photoacoustic method for characterization of natural galena (PbS)     

P. M. Nikolić  S. Ðurić  D. M. Todorović  D. Vasiljević-Radović  V. Blagojević  P. Mihajlović  J. Elazar  K. T. Radulović  A. I. Bojičić  D. Urošević 《Physics and Chemistry of Minerals》2001,28(1):44-51

Electron transport properties of single crystal and polycrystalline natural mineral galena (PbS) samples from the Trep?a mine, Yugoslavia, were determined using the photoacoustic frequency transmission technique. Their thermal diffusivity (D _T≈0.16 × 10^?5 m² s^?1), the coefficient of diffusion (D between 0.15×10^?2 0.16×10^?2 m² s^?1) and lifetime of the excess carrier (τ≈35 μs and the front and rear recombination velocity (s _g≈65.5 m s^?1 and s _b≈66.4 m s^?1, respectively), were calculated by comparing the experimental results and the theoretical photoacoustic amplitude and phase signals. The lattice parameter obtained by X-ray work was a?=5.936?Å. The free carrier concentration of these single-crystal samples was measured using the Hall method (N?=?3×10¹⁸ cm^?3). Measurements of the optical reflectivity of the same samples, as a function of wavelength, in the infrared and far infrared ranges, were performed. In the far infrared range a free electron plasma frequency was observed and numerically analyzed, using the least-squares fitting procedure. The values of optical parameters were calculated and the value of the free carrier concentration obtained by the Hall method was confirmed.  相似文献   

Preface     

Ivan Pšenčík  Vlastislav Červený  Luděk Klimeš 《Pure and Applied Geophysics》1996,148(1-2):1-1

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Frequency of quasi-geostrophic modes on hexagonal grids     

J. M. Popović  Dr. S. Ničković  M. B. Gavrilov 《Meteorology and Atmospheric Physics》1996,58(1-4):41-49

Summary Finite-difference analysis of Rossby modes has been performed for two staggered hexagonal grids. The solutions are compared with those obtained in analytical case and for rectangular grids. The result for one of the selected hexagonal grids better fits to the analytical solution then the results for the other considered grids. The obtained results may contribute to better understanding of the appropriateness of hexagonal grids in atmospheric and oceanographic modeling and numerical computations.With 6 Figures  相似文献   

Magnetic field measurements in India during the last two centuries     

A. Janáčkova  L. Urban  M. Chmelař 《Studia Geophysica et Geodaetica》1992,36(2):151-160

Summary The direction of the geomagnetic field has changed substantially less in India than in Europe since the end of the 18th century.Whereas the European geomagnetic time series indicate a tendency of secular variation from which a remarkable westward drift of the non-axial field can be deduced, in India the field direction seems to have remained more or less fixed over the last two centuries. The drift of the non-axial field seems to be very small, or even eastward.  相似文献   

A contribution to the measurement of frequency dependence of electrical conductivity of rocks     

Marcela Laštovičková  Josef Bochníček 《Studia Geophysica et Geodaetica》1992,36(1):94-99

Summary Some errors of method occurring in A. C. measurements of the electrical conductivity of rocks are discussed. It is demonstrated that the difference between A.C. and D.C. conductivities, at given frequency, depends mostly on the magnitude of the D.C. conductivity and magnitude of the dielectric constant.  相似文献   

Numerical model for rock bolts with consideration of rock joint movements   总被引：4，自引：0，他引：4  

Dr. M. Marenče  Dr. G. Swoboda 《Rock Mechanics and Rock Engineering》1995,28(3):145-165

Summary The stability of any underground structure during and after excavation is the most important question for designers, because any kind of collapse may destroy large parts of a finished tunnel, causing major repairs and time loss. Preliminary calculations are therefore of great importance. A calculation is only useful, however, when the underlying numerical model correctly describes natural behaviour. The rock bolts used in tunnel excavations are mostly untensioned grouted bolts, and this type of bolt is the main focus of this work. From the model of the grouted bolt, other types of rock bolts can also be modelled by the theory presented herein. Bolt behaviour in intact rock mass is so different from behaviour when a bolt intersects a joint, that a model with two different elements is suggested for a numerical calculation; one element for the bolt in the rock mass and one as a bolt intersecting with a joint.The model for both elements is verified by the experimental results. The numerical results correspond favourably with the experimental work. A variation of the parameters important for the behaviour of the bolt in intersection with the joint is shown. As an implementation of the bolt model, the numerical simulation of excavation and stabilisation of one road tunnel is presented.  相似文献   

Die la gefehler des trigonometrischen netzes der ČSR als indikator für die art der koordinatenumformung     

Karel Kučera 《Studia Geophysica et Geodaetica》1960,4(2):130-132

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