CO2增加引起的温室效应对我国沿海台风影响的数值模拟试验     

高学杰  林一骅  赵宗慈  Filippo Giorgi 《热带海洋学报》2003,22(4):77-83

使用RegCM2区域气候模式单向嵌套澳大利亚CSIRO R21L9全球海—气耦合模式，进行了CO2加倍情况下影响中国的台风变化的数值试验研究。首先分析了区域模式对中国气候的模拟能力，结果表明，区域模式由于具有较高的分辨率，因而对中国区域地面气温和降水的模拟效果较全球模式有了较大提高。随后就温室效应对台风的影响情况进行了分析，发现计算区域内台风生成的个数将有一定增加，而登陆我国的台风数目会有明显增加；同时台风的路径将以由南向北移动，在华南登陆影响我国的方式为主。  相似文献   

Experimental Assessment of the Stress–Strain Behaviour of Leighton Buzzard Sand for the Calibration of a Constitutive Model     

Giovanni Lanzano  Ciro Visone  Emilio Bilotta  Filippo Santucci de Magistris 《Geotechnical and Geological Engineering》2016,34(4):991-1012

A number of constitutive models are nowadays implemented in numerical codes which simulate the stress–strain behaviour of soil from very small to large strain. In this paper, the mechanical behaviour of Leighton Buzzard sand (grade E), used worldwide for physical modelling, has been thoroughly characterized by laboratory testing along several stress paths. Tests were aimed at calibrating a constitutive model, that allows considering stiffness nonlinearities in a wide range of strains, in the framework of isotropically hardening plasticity. As a validation, the results of dynamic centrifuge tests on a layer of the same sand were compared with finite element predictions.  相似文献   

Evaluation of microwave-assisted acid extraction procedures for the determination of metal content and potential bioavailability in sediments     

Cinzia Bettiol  Lorenzo Stievano  Mariangela Bertelle  Francesca Delfino  Emanuele Argese 《Applied Geochemistry》2008

Acid extractions represent a simple and effective tool for the assessment of metal contamination, origin and bioavailability in the aquatic environment. Optimized microwave-assisted procedures utilizing two extractions (8 M HNO₃ and 1 M HCl) were developed. Particular attention was given to the evaluation of efficiency and selectivity of the developed procedures. This involved an examination of the sediment and the extraction residues by Mössbauer spectroscopy and X-ray diffractometry. These instrumental approaches were used to identify the geochemical phases associated with acid decomposition. Microwave digestion with 8 M HNO₃ produced an efficient solubilization of the most important metal-bearing phases and left unaffected only the minerals (quartz, feldspars, muscovite) with a negligible metal content, thus providing a good estimate of the total metal concentrations. The 1 M HCl extraction, despite the limitation due to the incomplete solubilization of pyrite and to the partial dissolution of sheet silicates, represents a simple and effective technique for providing an estimate of the bioavailable metal fraction in sediments. The combined use of the two microwave-assisted acid extractions can provide a rapid and simple approach for the risk assessment of metal-polluted sediments.  相似文献   

Some limitations in using <Superscript>222</Superscript>Rn to assess river–groundwater interactions: the case of Castel di Sangro alluvial plain (central Italy)     

Luisa Stellato  Emma Petrella  Filippo Terrasi  Paolo Belloni  Maria Belli  Umberto Sansone  Fulvio Celico 《Hydrogeology Journal》2008,16(4):701-712

²²²Rn was used to assess river–groundwater interactions within Castel di Sangro alluvial aquifer (Italy). The effectiveness of results obtained through this indicator was verified by also analyzing δ¹⁸O, major ions and temperature in both surface and groundwater, and carrying out piezometric head monitoring and discharge measurements. Hydrogeological investigations suggested that the river infiltrates into the aquifer in the south-eastern aquifer portion, while groundwater discharges into the river in the north-eastern portion. The latter phenomenon is supported by ²²²Rn data. Nevertheless, flow-through conditions cause the modelled discharge along this river reach, estimated by ²²²Rn data in a degassing-corrected two-component mixing model, to be greater than the measured discharge. Concerning river infiltration into the aquifer, δ¹⁸O, major ions and temperature data show that the river contribution is negligible in terms of aquifer recharge. Thus, the observed increase in ²²²Rn concentration in that portion of the aquifer is due to the enrichment process caused by infiltration of rainwater (²²²Rn free) which flows from the local divide area. Hence, in the study site, the use of only ²²²Rn to predict river–groundwater interactions causes some estimation inaccuracies and it must be coupled with other hydrochemical and hydrogeological parameters to gain a thorough understanding of such interactions.  相似文献   

A multimodel intercomparison of resolution effects on precipitation: simulations and theory     

Sara A. Rauscher  Travis A. O’Brien  Claudio Piani  Erika Coppola  Filippo Giorgi  William D. Collins  Patricia M. Lawston 《Climate Dynamics》2016,47(7-8):2205-2218

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2D numerical simulations of earthquake ground motion: examples from the Marche Region,Italy     

Giovanna Laurenzano  Enrico Priolo  Emanuele Tondi 《Journal of Seismology》2008,12(3):395-412

A detailed numerical simulation of the ground motion and a site response analysis for two towns in the Marche Region (Treia and Cagli) is carried out on the basis of structural models deduced from available geological and geophysical data. In both cases, the reference event is an M = 5.7 earthquake associated with a normal fault located beneath each town. The ground motion is computed using the 2D spectral element method (SPEM 2D). The method solves the propagation of the seismic field through complex geological structures and enables an estimate of the effects of deep crustal structure, superficial geology, and topography on ground motion. Numerical simulations of the seismic field are performed along 2D vertical planes containing the seismic source. Strong ground motion has not been yet recorded in the two towns; therefore, the numerical simulation of ground motion represents a way to overcome the lack of instrumental data. The simulations carried out for Treia show that ground motion is influenced by both source mechanism and effects due to propagation through the geological structure, while ground motion in Cagli features strong local effects, caused by the presence of alluvial deposits under a large area of the town.  相似文献   

The pressure-induced ringwoodite to Mg-perovskite and periclase post-spinel phase transition: a Bader’s topological analysis of the ab initio electron densities     

Filippo?ParisiEmail author  Luciana?Sciascia  Francesco?Princivalle  Marcello?Merli 《Physics and Chemistry of Minerals》2012,39(2):103-113

In order to characterize the pressure-induced decomposition of ringwoodite (γ-Mg₂SiO₄), the topological analysis of the electron density ρ(r), based upon the theory of atoms in molecules (AIM) developed by Bader in the framework of the catastrophe theory, has been performed. Calculations have been carried out by means of the ab initio CRYSTAL09 code at the HF/DFT level, using Hamiltonians based on the Becke- LYP scheme containing hybrid Hartree–Fock/density functional exchange–correlation terms. The equation of state at 0 K has been constructed for the three phases involved in the post-spinel phase transition (ringwoodite → Mg-perovskite + periclase) occurring at the transition zone–lower mantel boundary. The topological results show that the decomposition of the ringwoodite at high pressures is caused by a conflict catastrophe. Furthermore, topological evidences of the central role played by the oxygen atoms to facilitate the pressure-induced ringwoodite decomposition and the subsequent phase transition have been noticed.  相似文献   

Open issues on the synthesis of evolved stellar populations at ultraviolet wavelengths     

Miguel Chavez  Emanuele Bertone 《Astrophysics and Space Science》2011,332(1):193-199

This paper deals with five-dimensional black hole solutions in (a) Einstein-Maxwell-Gauss-Bonnet theory with a cosmological constant and (b) Einstein-Yang-Mills-Gauss-Bonnet theory for spherically symmetric space time. In both the cases the possibility of phase transition is examined and it is analyzed whether the phase transition is a Hawking-Page type phase transition or not.  相似文献   

Statistical properties of the <Emphasis Type="Italic">GALEX</Emphasis> spectroscopic stellar sample     

Emanuele Bertone  Miguel Chavez 《Astrophysics and Space Science》2011,335(1):69-76

The GALEX General Data Release 4/5 includes 174 spectroscopic tiles, obtained from slitless grism observations, for a total of more than 60 000 ultraviolet spectra. We have determined statistical properties of the sample of GALEX stars. We have defined a suitable system of spectroscopic indices, which measure the main mid-UV features at the GALEX low spectral resolution and we have employed it to determine the atmospheric parameters of stars in the range 4500≲T _eff≲9000 K. Our preliminary results indicate that the majority of the sample is formed by main sequence F- and G-type stars, with metallicity [M/H]≳−1 dex.  相似文献   

Interacting Winds in Eclipsing Symbiotic Systems – The Case Study of EG Andromedae     

Emanuele Calabrò 《Journal of Astrophysics and Astronomy》2014,35(1):69-85

We report the mathematical representation of the so called eccentric eclipse model, whose numerical solutions can be used to obtain the physical parameters of a quiescent eclipsing symbiotic system. Indeed the nebular region produced by the collision of the stellar winds should be shifted to the orbital axis because of the orbital motion of the system. This mechanism is not negligible, and it led us to modify the classical concept of an eclipse. The orbital elements obtained from spectroscopy and photometry of the symbiotic EG Andromedae were used to test the eccentric eclipse model. Consistent values for the unknown orbital elements of this symbiotic were obtained. The physical parameters are in agreement with those obtained by means of other simulations for this system.  相似文献