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1.
The complete travel-time equation of state (CT-EOS) is presented by utilizing thermodynamics relations, such as; $$K_T = K_S (1 + \alpha \gamma T)^{ - 1} , \gamma = \frac{{\alpha K_S }}{{\rho C_P }}, \left. {\frac{{\partial C_P }}{{\partial P}}} \right)_T = - \frac{T}{\rho }\left[ {\alpha ^2 + \left. {\frac{{\partial \alpha }}{{\partial T}}} \right)_P } \right], etc.$$ The CT-EOS enables us to analyze ultrasonic experimental data under simultaneous high pressure and high temperature without introducing any assumption, as long as the density, or thermal expansivity, and heat capacity are also available as functions of temperature at zero pressure. The performance of the CT-EOS was examined by using synthesized travel-time data with random noise of 10?5 and 10?4 amplitude up to 4 GPa and 1500 K. Those test conditions are to be met with the newly developed GHz interferometry in a gas medium piston cylinder apparatus. The results suggest that the combination of the CT-EOS and accurate experimental data (10?4 in travel time) can determine thermodynamic and elastic parameters, as well as their derivatives with unprecedented accuracy, yielding second-order pressure derivatives (?2 M/?P 2) of the elastic moduli as well as the temperature derivatives of their first-order pressure derivatives ?2 M/?P?T). The completeness of the CT-EOS provides an unambiguous criterion to evaluate the compatibility of empirical EOS with experimental data. Furthermore because of this completeness, it offers the possibility of a new and absolute pressure calibration when X-ray (i.e., volume) measurements are made simultaneously with the travel-time measurements. 相似文献
2.
Hartmut Schulz 《Astrophysics and Space Science》1990,171(1-2):21-23
Rotating disks and expanding supershells of ionized gas are supposed to be kinematical components essential for the formation of emission-like profiles from starburst nuclei and the narrow-line regions of Seyfert galaxies. Simple models predict a few typical features of line profiles by which disks may be recognized.A giant supershell is identified SE of the nucleus of the starburst galaxy NGC 253. We suggest that the variously reported outflow cones in Seyfert nuclei are also induced by superbubble dynamics. Observations of NGC 4151 are shown to be consistent with this scenario.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain. 相似文献
3.
About 30 samples representing major lithologies of Sulu ultrahigh-pressure (UHP) metamorphic rocks were collected from surface exposures and exploration wells, and compressional (Vp) and shear wave (Vs) velocities and their directional dependence (anisotropy) were determined over a range of constant confining pressures up to 600 MPa and temperatures ranging from 20 to 600 °C. Samples range in composition from acidic to ultramafic. P- and S-wave velocities measured at 600 MPa vary from 5.08 to 8.64 km/s and 2.34 to 4.93 km/s, respectively. Densities are in the range from 2.60 to 3.68 g/cm3. To make a direct tie between seismic measurements (refraction and reflection) and subsurface lithologies, the experimental velocity data (corresponding to shallow depths) were used to calculate velocity profiles for the different lithologies and profiles of reflection coefficients at possible lithologic interfaces across the projected 5000-m Chinese Continental Scientific Drilling Program (CCSD) crustal segment. Comparison of calculated in situ velocities with respective intrinsic velocities suggests that the in situ velocities at shallow depths are lowered by an increased abundance of open microcracks. The strongly reflective zone beneath the Donghai drill site can be explained by the impedance contrasts between the different lithologies. Contacts between eclogite/peridotite and felsic rocks (gt-gneiss, granitic gneiss), in particular, may give rise to strong seismic reflections. In addition, shear-induced (lattice preferred orientation (LPO)-related) seismic anisotropy can increase reflectivity. For the explanation of the high velocity bodies (>6.4 km/s) around 1000 m and below 3200-m depth, large proportions of eclogite/peridotite (about 40 and 30 vol.%, respectively) are needed. 相似文献
4.
5.
Hans Hartmut Schock 《Contributions to Mineralogy and Petrology》1966,13(2):161-180
Distribution of Cs, Na, and Ba between great monocrystals of KCl and water solution was investigated. Impurity was either labelled by long-lived radioactive isotopes or was activated after growth of the crystals by neutrons in a nuclear reactor. No influence on partition coefficients was caused by using radioactive tracers, e.g. due to raised inclusion of mother liquor. Between impurity concentrations from 3·10–4 to 10–1 in the solution the partition coefficients were nearly constant and about 10–3 for Na, about 10–4 for Cs, and <5·10–5 for Ba in KCl at temperatures of 40° C. If different impurity ions were built in simultaneously, the partition coefficients were independent of composition of solution. In case of Cs in KCl capture of Cs increased with increasing temperature.
Meinem hoehverehrten Lehrer, Herrn Prof. Dr. W. von Engelhart, danke ieh für die freundliehe Überlassung des interessanten Themas. Für die stete Förderung und die zahlreichen fruehtbaren Diskussionen und Anregungen bin ich ihm und Herrn Dr. H. Puchelt zu großem Dank verpflichtet.Dem Bundesnlinisterium für wissensehaftliehe Forsehung danke ieh ffir die großzügige Unterstützung der Arbeit.Herrn Prof. Dr. W. Seelmann-Eggebert und Herrn Dr. V. Schneider vom Kernforsehungszentrum Karlsruhe und Herrn Dr. Bartel von der Kernforsehungsanlage Jülich danke ich für die Unterstützung bei der Neutronenaktivierung und Herrn Dr. J. Ottemann vom Mineralogischen Instigut der Universität Heidelberg für die Untersuchung mit der Elektronenmikrosonde. 相似文献
Meinem hoehverehrten Lehrer, Herrn Prof. Dr. W. von Engelhart, danke ieh für die freundliehe Überlassung des interessanten Themas. Für die stete Förderung und die zahlreichen fruehtbaren Diskussionen und Anregungen bin ich ihm und Herrn Dr. H. Puchelt zu großem Dank verpflichtet.Dem Bundesnlinisterium für wissensehaftliehe Forsehung danke ieh ffir die großzügige Unterstützung der Arbeit.Herrn Prof. Dr. W. Seelmann-Eggebert und Herrn Dr. V. Schneider vom Kernforsehungszentrum Karlsruhe und Herrn Dr. Bartel von der Kernforsehungsanlage Jülich danke ich für die Unterstützung bei der Neutronenaktivierung und Herrn Dr. J. Ottemann vom Mineralogischen Instigut der Universität Heidelberg für die Untersuchung mit der Elektronenmikrosonde. 相似文献
6.
Coleps hirtus viridis was the dominant species of the planktonic ciliate community of Lake Fühlinger See (Germany) during the study in 1999 and 2000. Total ciliate densities ranged from 120 to 42,000 ind. l−1 in 1999 and up to 8,000 ind. l−1 in 2000. Coleps contributed up to 98% to both total ciliate abundance and biomass and made up an average of 64% of the total ciliate biomass. Oligotrichs (Rimostrombidium, Strobilidium) dominated the epilimnetic zone, whereas peritrich ciliates (Pelagovorticella, Vorticella) were predominantly located in the hypolimnion. The population maximum of Coleps changed locations from the epilimnion in early summer to the hypolimnion (up to 40,000 ind. l−1) during stratification. High growth rates in the hypolimnion, presence of endosymbiontic algae and the ability to ingest detritus seem to be important for the success.Growth rates of Coleps in June were determined by Landry-Hassett dilution experiments in both the epilimnion and the hypolimnion. The instantaneous growth rates were similar in both layers (0.6 d−1), but a distinctly higher instantaneous mortality was estimated for the epilimnion. These high loss rates may be due to grazing pressure by cladocerans.The significance of the histophagous feeding of Coleps was evaluated through an experiment using killed zooplankton. Parts of Daphnia magna were incorporated at rates of about 1,100 μm3 ind.−1 h−1 by Coleps without endosymbiotic algae and at rates of 500 μm3 ind.−1 h−1 by Coleps with endosymbionts. These high feeding rates support the conclusion that Coleps can use dead organic matter as an additional food source. 相似文献
7.
We utilise a global finite-element sea ice–ocean model (FESOM), focused on the Antarctic marginal seas, to analyse projections of ice shelf basal melting in a warmer climate. Ice shelf–ocean interaction is described using a three-equation system with a diagnostic computation of temperature and salinity at the ice–ocean interface. A tetrahedral mesh with a minimumhorizontal resolution of 4 km and hybrid vertical coordinates is used. Ice shelf draft, cavity geometry, and global ocean bathymetry have been derived from the RTopo-1 data set. The model is forced with the atmospheric output from two climate models: (1) the Hadley Centre Climate Model (HadCM3) and (2) Max Planck Institute’s ECHAM5/MPI-OM coupled climate model. Results from experiments forced with their twentieth century output are used to evaluate the modelled present-day ocean state. Sea ice coverage is largely realistic in both simulations; modelled ice shelf basal melt rates compare well with observations in both cases, but are consistently smaller for ECHAM5/MPI-OM. Projections for future ice shelf basal melting are computed using atmospheric output for the Intergovernmental Panel on Climate Change (IPCC) scenarios E1 and A1B. In simulations forced with ECHAM5 data, trends in ice shelf basal melting are small. In contrast, decreasing convection along the Antarctic coast in HadCM3 scenarios leads to a decreasing salinity on the continental shelf and to intrusions of warm deep water of open ocean origin. In the case of the Filchner–Ronne Ice Shelf (FRIS), this water reaches deep into the cavity, so that basal melting increases by a factor of 4 to 6 compared to the present value of about 90 Gt/year. By the middle of the twenty-second century, FRIS becomes the dominant contributor to total ice shelf basal mass loss in these simulations. Our results indicate that the surface freshwater fluxes on the continental shelves may be crucial for the future of especially the large cold water ice shelves in the Southern Ocean. 相似文献
8.
Hartmut H. Hellmer Monika Rhein Günther Heinemann Janna Abalichin Wafa Abouchami Oliver Baars Ulrich Cubasch Klaus Dethloff Lars Ebner Eberhard Fahrbach Martin Frank Gereon Gollan Richard J. Greatbatch Jens Grieger Vladimir M. Gryanik Micha Gryschka Judith Hauck Mario Hoppema Oliver Huhn Torsten Kanzow Boris P. Koch Gert König-Langlo Ulrike Langematz Gregor C. Leckebusch Christof Lüpkes Stephan Paul Annette Rinke Bjoern Rost Michiel Rutgers van der Loeff Michael Schröder Gunther Seckmeyer Torben Stichel Volker Strass Ralph Timmermann Scarlett Trimborn Uwe Ulbrich Celia Venchiarutti Ulrike Wacker Sascha Willmes Dieter Wolf-Gladrow 《Ocean Dynamics》2016,66(11):1379-1413
9.
Seismic lamination and anisotropy of the Lower Continental Crust 总被引:2,自引:3,他引:2
Seismic lamination in the lower crust associated with marked anisotropy has been observed at various locations. Three of these locations were investigated by specially designed experiments in the near vertical and in the wide-angle range, that is the Urach and the Black Forrest area, both belonging to the Moldanubian, a collapsed Variscan terrane in southern Germany, and in the Donbas Basin, a rift inside the East European (Ukrainian) craton. In these three cases, a firm relationship between lower crust seismic lamination and anisotropy is found. There are more cases of lower-crustal lamination and anisotropy, e.g. from the Basin and Range province (western US) and from central Tibet, not revealed by seismic wide-angle measurements, but by teleseismic receiver function studies with a P–S conversion at the Moho. Other cases of lamination and anisotropy are from exhumed lower crustal rocks in Calabria (southern Italy), and Val Sesia and Val Strona (Ivrea area, Northern Italy). We demonstrate that rocks in the lower continental crust, apart from differing in composition, differ from the upper mantle both in terms of seismic lamination (observed in the near-vertical range) and in the type of anisotropy. Compared to upper mantle rocks exhibiting mainly orthorhombic symmetry, the symmetry of the rocks constituting the lower crust is either axial or orthorhombic and basically a result of preferred crystallographic orientation of major minerals (biotite, muscovite, hornblende). We argue that the generation of seismic lamination and anisotropy in the lower crust is a consequence of the same tectonic process, that is, ductile deformation in a warm and low-viscosity lower crust. This process takes place preferably in areas of extension. Heterogeneous rock units are formed that are generally felsic in composition, but that contain intercalations of mafic intrusions. The latter have acted as heat sources and provide the necessary seismic impedance contrasts. The observed seismic anisotropy is attributed to lattice preferred orientation (LPO) of major minerals, in particular of mica and hornblende, but also of olivine. A transversely isotropic symmetry system, such as expected for sub-horizontal layering, is found in only half of the field studies. Azimuthal anisotropy is encountered in the rest of the cases. This indicates differences in the horizontal components of tectonic strain, which finally give rise to differences in the evolution of the rock fabric. 相似文献
10.
Ocean/ice interaction at the base of deep-drafted Antarctic ice shelves modifies the physical properties of inflowing shelf
waters to become Ice Shelf Water (ISW). In contrast to the conditions at the atmosphere/ocean interface, the increased hydrostatic
pressure at the glacial base causes gases embedded in the ice to dissolve completely after being released by melting. Helium
and neon, with an extremely low solubility, are saturated in glacial meltwater by more than 1000%. At the continental slope
in front of the large Antarctic caverns, ISW mixes with ambient waters to form different precursors of Antarctic Bottom Water.
A regional ocean circulation model, which uses an explicit formulation of the ocean/ice shelf interaction to describe for
the first time the input of noble gases to the Southern Ocean, is presented. The results reveal a long-term variability of
the basal mass loss solely controlled by the interaction between waters of the continental shelf and the ice shelf cavern.
Modeled helium and neon supersaturations from the Filchner–Ronne Ice Shelf front show a “low-pass” filtering of the inflowing
signal due to cavern processes. On circumpolar scales, the simulated helium and neon distributions allow us to quantify the
ISW contribution to bottom water, which spreads with the coastal current connecting the major formation sites in Ross and
Weddell Seas.
相似文献
Christian B. RodehackeEmail: |