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Geotechnical and Geological Engineering - An analytical model defining soil-foundation probability of failure with respect to total system stability was developed in the present study. Soil... 相似文献
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A radial deformation of the Reissner-Nordstr?m metric which leads to the appearance of charged, traversable wormholes is investigated.
It is shown that the resulting wormholes are not covered by event horizons and physical signals can travel between the two
parallel universes either way across the wormhole. The status of energy conditions and the classification of geodesics are
also discussed in details. 相似文献
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J. M. Liotard J. M. Dautria D. Bosch M. Condomines H. Mehdizadeh J.-F. Ritz 《International Journal of Earth Sciences》2008,97(1):89-102
The activity of the Damavand volcano (Central Alborz, northern Iran) began 1.8 Ma ago and continued up to 7 ka BP. Although
the volcanic suite is clearly of shoshonitic affinity, only two petrographic types can be distinguished in the studied lavas:
(1) weakly differentiated absarokites (49 < %SiO2 < 51), scattered around the volcano but with a regional extension, (2) highly differentiated banakites (59 < %SiO2 < 63), which form the bulk of the 4,000 m thick volcanic pile. All lavas are alkalic (3.7 < %K2O < 5), REE and LILE-rich (e.g., 85 < La < 148 ppm; 9 < Th < 32 ppm) and show highly fractionated REE patterns (69 < La/Yb < 115)
and pronounced Nb–Ta negative anomalies. The absarokites are characterised by Sr (0.7045–0.7046) and Nd (0.51266–0.51269)
isotope compositions close to the Bulk Earth values, and distinct from those of the banakites (0.7047 < 87Sr/86Sr < 0.7049, 0.51258 < 143Nd/144Nd < 0.51262). The Pb isotope ratios are also slightly lower in the absarokites than in the banakites (18.71 < 206Pb/204Pb < 18.77, 15.62 < 207Pb/204Pb < 15.63, 38.85 < 208Pb/204Pb < 38.91, and 18.77 < 206Pb/204Pb < 18.84, 15.62 < 207Pb/204Pb < 15.64, 38.94 < 208Pb/204Pb < 39.06, respectively). Overall, there is a clear tendency towards higher Sr, Pb and lower Nd isotope ratios with increasing
degree of differentiation. This study suggests that the absarokites result from a low degree of partial melting (∼5%) of a
highly metasomatized mantle source, which inherited its characteristics from an old subduction setting. The initiation of
volcanic activity 1.8 Ma ago results from variations in the lithospheric thermal regime, probably related to lithospheric
delamination as proposed for Anatolia (Pearce et al. 1990). The banakites are mainly generated by extensive fractional crystallisation (∼70%) of the absarokitic magma, with a limited
amount (a few percents) of assimilation of an old crustal component, in the form of bulk assimilation or AFC processes, which
both can explain the Sr, Nd and Pb isotope data. 相似文献
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Soil temperature has an important role in agricultural, hydrological, meteorological and climatological studies. In the present research, monthly mean soil temperature at four different depths (5, 10, 50 and 100 cm) was estimated using artificial neural networks (ANN), adaptive neuro-fuzzy inference system (ANFIS) and gene expression programming (GEP). The monthly mean soil temperature data of 31 stations over Iran were employed. In this process, the data of 21 and 10 stations were used for training and testing stages of used models, respectively. Furthermore, the geographical information including latitude, longitude and altitude as well as periodicity component (the number of months) was considered as inputs in the mentioned intelligent models. The results demonstrated that the ANN and ANFIS models had good performance in comparison with the GEP model. Nevertheless, the ANFIS generally performed better than ANN model. 相似文献
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Hossein Mehdizadeh Jean-Michel Liotard Jean-Marie Dautria 《Comptes Rendus Geoscience》2002,334(2):111-117
Lavas of the Quaternary Damavand volcano (Central Alborz, Northern Iran) have been analysed for major and trace elements. The shoshonitic character of this magmatic series is definitively confirmed and most samples correspond to banakites. The Nb, Ta and Ti negative anomalies observed in all lavas suggest that they derive from of a sub-continental lithosphere metasomatised in a subduction setting. Their variable trace element enrichments are explained both by mineral fractionation and by crustal contamination in a shallow magmatic chamber. To cite this article: H. Mehdizadeh et al., C. R. Geoscience 334 (2002) 111–117. 相似文献
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Geotectonics - The Kazerun fault system as an active transverse fault has affected the structures and sedimentation of the Zagros belt from Cambrian to the present. On the basis of published... 相似文献
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Comprehensive modeling of monthly mean soil temperature using multivariate adaptive regression splines and support vector machine 总被引:1,自引:1,他引:0
Saeid?Mehdizadeh Javad?BehmaneshEmail author Keivan?Khalili 《Theoretical and Applied Climatology》2018,133(3-4):911-924
Soil temperature (T s) and its thermal regime are the most important factors in plant growth, biological activities, and water movement in soil. Due to scarcity of the T s data, estimation of soil temperature is an important issue in different fields of sciences. The main objective of the present study is to investigate the accuracy of multivariate adaptive regression splines (MARS) and support vector machine (SVM) methods for estimating the T s. For this aim, the monthly mean data of the T s (at depths of 5, 10, 50, and 100 cm) and meteorological parameters of 30 synoptic stations in Iran were utilized. To develop the MARS and SVM models, various combinations of minimum, maximum, and mean air temperatures (T min, T max, T); actual and maximum possible sunshine duration; sunshine duration ratio (n, N, n/N); actual, net, and extraterrestrial solar radiation data (R s, R n, R a); precipitation (P); relative humidity (RH); wind speed at 2 m height (u 2); and water vapor pressure (Vp) were used as input variables. Three error statistics including root-mean-square-error (RMSE), mean absolute error (MAE), and determination coefficient (R 2) were used to check the performance of MARS and SVM models. The results indicated that the MARS was superior to the SVM at different depths. In the test and validation phases, the most accurate estimations for the MARS were obtained at the depth of 10 cm for T max, T min, T inputs (RMSE = 0.71 °C, MAE = 0.54 °C, and R 2 = 0.995) and for RH, V p, P, and u 2 inputs (RMSE = 0.80 °C, MAE = 0.61 °C, and R 2 = 0.996), respectively. 相似文献
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