Liapunov instability of the hypoplastic model for soils     

Andrzej Niemunis  Theodor Triantafyllidis 《Soil Dynamics and Earthquake Engineering》2004,24(1):35-48

The hypoplastic constitutive model is known for its numerous application to the problems of soil mechanics and also for its excessive ratcheting. The paper shows that this deficiency can be interpreted as Liapunov instability in dynamic case. This is demonstrated with a simple one-dimensional swinger. Infinitesimally small as well as finite oscillations are analytically examined and the variability of stiffness upon a single cycle is considered. Several methods to circumvent the problem of ratcheting are discussed: implementation of ‘elastic’ range by means of so-called intergranular strain, usage of overlay modelling with parallel coupling of hypoplastic materials as originally proposed by Valanis in his endochronic theory and a special coupling of hypoplastic models based on comparison of partial stiffnesses.  相似文献   

Analysis of the high-resolution Mg XI X-ray spectra     

G. Bromboszcz  M. Siarkowski  J. Sylwester  V. V. Korneev  S. L. Mandelshtam  S. N. Oparin  A. M. Urnov  I. A. Zhitnik 《Solar physics》1983,83(2):243-255

In Part IV of the series of papers about the analysis of the INTERCOSMOS 16 ADP spectra a method is developed to evaluate plasma densities from measured resonance, intercombination, and forbidden helium-like Mg xi line intensities, using plots of the so-called G and R ratios. The density is close to the low-density limit. For the active region McMath 14352 a correlation between mean plasma density and electron temperature has been found, in agreement with earlier results. In an appendix systematic differences between measured and calculated line fluxes in all bands A to F are discussed.  相似文献   

On the influence of relativistic effects on X-ray variability of accreting black holes     

Piotr T. &#;ycki  Andrzej Nied&#;wiecki 《Monthly notices of the Royal Astronomical Society》2005,359(1):308-314

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The superorbital variability and triple nature of the X-ray source 4U 1820–303     

Andrzej A. Zdziarski  Linqing Wen  Marek Gierli&#;ski 《Monthly notices of the Royal Astronomical Society》2007,377(3):1006-1016

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Non-Integrability of the Generalized Two Fixed Centres Problem     

Andrzej J. Maciejewski  Maria Przybylska 《Celestial Mechanics and Dynamical Astronomy》2004,89(2):145-164

We consider two fixed centres attracting a third body. Each centre is the source of a force field with potential V=−ar ⁻²ⁿ , where n is a real number. We prove that this generalization of the classical two fixed centres problem is non-integrable except when n= 0, 1/2, −1 and −2. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Identification of seismic anomalies caused by gas saturation on the basis of theoretical P and PS wavefield in the Carpathian Foredeep,SE Poland     

Kaja Pietsch  Paweł Marzec  Marcin Kobylarski  Tomasz Danek  Andrzej Leśniak  Artur Tatarata  Edward Gruszczyk 《Acta Geophysica》2007,55(2):191-208

The thin-layer build of the Carpathian Foredeep Miocene formations and large petrophysical parameter variation cause seismic images of gas-saturated zones to be ambiguous, and the location of prospection wells on the basis of anomalous seismic record is risky. A method that assists reservoir interpretation of standard recorded seismic profiles (P waves) can be a converted wave recording (PS waves). This paper presents the results of application of a multicomponent seismic survey for the reservoir interpretation over the Chałupki Dębniańskie gas deposit, carried out for the first time in Poland by Geofizyka Kraków Ltd. for the Polish Oil and Gas Company. Seismic modeling was applied as the basic research tool, using the SeisMod program based on the finite-difference solution of the acoustic wave equation and equations of motion. Seismogeological models for P waves were developed using Acoustic Logs; S-wave model (records only from part of the well) was developed on the basis of theoretical curves calculated by means of the Estymacja program calibrated with average S-velocities, calculated by correlation of recorded P and PS wavefields with 1D modeling. The conformity between theoretical and recorded wavefields makes it possible to apply the criteria established on the basis of modeling for reservoir interpretation. Direct hydrocarbon indicators (bright spots, phase change, time sag) unambiguously identify gas-prone layers within the ChD-2 prospect. A partial range of the indicators observed in the SW part of the studied profile (bright spot that covers a single, anticlinally bent seismic horizon) points to saturation of the horizon. The proposed location is confirmed by criteria determined for converted waves (continuous seismic horizons with constant, high amplitude) despite poorer agreement between theoretical and recorded wavefields.  相似文献   

Reconstructing cosmic peculiar velocities from the mildly non-linear density field     

Andrzej Kudlicki  Micha&#; Chodorowski  Tomasz Plewa  Micha&#; Ró&#;yczka 《Monthly notices of the Royal Astronomical Society》2000,316(3):464-472

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Statistical tools for maximum possible earthquake magnitude estimation   总被引：9，自引：1，他引：8  

Andrzej Kijko  Mayshree Singh 《Acta Geophysica》2011,59(4):674-700

Several procedures for the statistical estimation of the region-characteristic maximum possible earthquake magnitude, m _max, are currently available. This paper aims to introduce and compare the 12 existing procedures. For each of the procedures given, there are notes on its origin, assumptions made in its derivation, condition for validity, weak and strong points, etc. The applicability of each particular procedure is determined by the assumptions of the model and/or the available information on seismicity of the area.  相似文献   

Analysis of the high resolution Mg XI X-ray spectra     

M. Siarkowski  J. Sylwester  G. Bromboszcs  V. V. Korneev  S. L. Mandelshtam  S. N. Oparin  A. M. Urnov  I. A. Zhitnik 《Solar physics》1982,81(1):63-68

In part III of the paper containing the analysis of the INTERCOSMOS 16 ADP spectra, it is shown that by assuming the existence of a small admixture (1%) of non-thermal electrons in the active-region plasma it is possible to improve the agreement between measured and calculated fluxes for some spectra. The analysis follows the suggestion contained in the paper by Karev et al. (1980).  相似文献   

Preface     

Bonnie A. Stevens  Andrzej J. Maciejewski 《Celestial Mechanics and Dynamical Astronomy》2004,90(1-2):1-2

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