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991.
Satluj Valley is known to have a history of landslides and related mass movement activities since the geological times. Geological and geomorphological settings combined with anthropogenic activities constitute a propensity towards slope failure. During the last two decades,the area witnessed substantial increase in athropogenic pressure,mainly due to the exploitation of hydropower potential,changing landuse pattern and population growth. In addition,a shift of the climatic patterns in the form of larger area falling under the influence of rains was observed. These natural as well as anthropogenic changes in the area have resulted in increased spatial coverage of landslide in the area. This paper documents these changes during 1990~2006. 相似文献
992.
S. K. Pandey J. P. Shrivastava G. S. Roonwal 《Journal of the Geological Society of India》2009,74(5):559-572
Mid-Oceanic Ridge Basalt (MORB) samples collected from southern East Pacific Rise (SEPR) have been investigated. These highly phyric plagioclase basalts (HPPB) and moderately phyric plagioclase basalts (MOPB) show rare cumulate and vitrophyric textures with plagioclase (>10% as phenocryst) and abundant glass (>72%). Electron Probe Micro Analysis (EPMA) showed large compositional variations in the megacrysts as well as microcrysts of plagioclase (An62 to An82), olivine (Fo78 to Fo87), pyroxene (ferroaugite to augite) and iron oxides, mostly titaniferous magnetite. Olivine grains show high Mg# (>80%) and distinctly low in NiO (0.01–0.2%). Ferroan trevorite (NiO =16.22 and FeO(t) =83.06) a characteristic meteoritic mineral has been identified from the olivine megacrysts of MORB, possibly attributed to Ni-enrichment, resulted from heterogeneity of the lower mantle. Wide range of An composition in plagioclase is indicative of large pressure range of crystal nucleation under decompression at a depth of ∼70 km (An82) up to the ocean spreading centre. Absence of zoning observed in all the minerals present in the MORB samples, possibly attributed to unmixing and dominant fractionation process. 相似文献
993.
Multicomponent reactive transport modeling of uranium bioremediation field experiments 总被引:1,自引:0,他引:1
Yilin Fang Steven B. Yabusaki James P. Amonette 《Geochimica et cosmochimica acta》2009,73(20):6029-290
A reaction network integrating abiotic and microbially mediated reactions has been developed to simulate biostimulation field experiments at a former Uranium Mill Tailings Remedial Action (UMTRA) site in Rifle, Colorado. The reaction network was calibrated using data from the 2002 field experiment, after which it was applied without additional calibration to field experiments performed in 2003 and 2007. The robustness of the model specification is significant in that (1) the 2003 biostimulation field experiment was performed with 3 times higher acetate concentrations than the previous biostimulation in the same field plot (i.e., the 2002 experiment), and (2) the 2007 field experiment was performed in a new unperturbed plot on the same site. The biogeochemical reactive transport simulations accounted for four terminal electron-accepting processes (TEAPs), two distinct functional microbial populations, two pools of bioavailable Fe(III) minerals (iron oxides and phyllosilicate iron), uranium aqueous and surface complexation, mineral precipitation and dissolution. The conceptual model for bioavailable iron reflects recent laboratory studies with sediments from the UMTRA site that demonstrated that the bulk (∼90%) of initial Fe(III) bioreduction is associated with phyllosilicate rather than oxide forms of iron. The uranium reaction network includes a U(VI) surface complexation model based on laboratory studies with Rifle site sediments and aqueous complexation reactions that include ternary complexes (e.g., calcium-uranyl-carbonate). The bioreduced U(IV), Fe(II), and sulfide components produced during the experiments are strongly associated with the solid phases and may play an important role in long-term uranium immobilization. 相似文献
994.
995.
The present paper deals with the inhibition of the specific activity of the acid and alkaline phosphatases in the kidney tissue of mudskipper Boleophthalmus dentatus, exposed to different sublethal concentrations of mercuric chloride. There was a more or less linear inhibition of the specific activity of both the enzymes with increasing concentration of mercuric chloride as well as exposure time. The inhibition of acid phosphatase could be due to the rupture of lysosomal membrane in the presence of mercury compound, which acts as a labilizing agent. The inhibition of alkaline phosphatase probably caused a breakdown of the membrane transport system. 相似文献
996.
H. Tissoux H. Valladas P. Voinchet J.L. Reyss N. Mercier C. Falguères J.-J. Bahain L. Zöller P. Antoine 《Quaternary Geochronology》2010,5(2-3):131-136
As part of a chronological study of the famous Upper Pleistocene Nussloch (Germany) loess sequence, three samples were collected to check the applicability of palaeodosimetric dating methods (OSL and ESR) to quartz grains. The ESR-multicentre method showed a partial bleaching of the ESR centers in aeolian sands. This partial bleaching was also observed by OSL. Laminated loess seemed to be sufficiently bleached but showed a large scatter of the doses, which we ascribed to heterogeneous responses of the luminescent grains to the SAR protocol. Ages could nevertheless be calculated for the three samples and were found to be somewhat older than the IRSL and 14C ages obtained for the same layers of the laminated loess. 相似文献
997.
A. S. Buslov Yu. D. Kotov V. N. Yurov M. V. Bessonov P. A. Kalmykov E. M. Oreshnikov A. M. Alimov A. V. Tumanov E. A. Zhuchkova 《Solar System Research》2011,45(3):226-230
This paper deals with the organizational structure of ground-based receiving, processing, and dissemination of scientific
information created by the Astrophysics Institute of the Scientific Research Nuclear University, Moscow Engineering Physics
Institute. Hardware structure and software features are described. The principles are given for forming sets of control commands
for scientific equipment (SE) devices, and statistics data are presented on the operation of facility during flight tests
of the spacecraft (SC) in the course of one year. 相似文献
998.
A study has been made of a dynamical system composed of a pendulum and a harmonic oscillator, in order to show the remarkable resemblance with many classical celestial mechanics problems, in particular the restricted three-body problem. It is shown that the well-known investigations of periodic orbits can be applied to the present dynamics problem.Presented at the Conference on Celestial Mechanics, Oberwolfach, Germany, August 27–September 2, 1972. 相似文献
999.
P. Descamps 《Icarus》2010,207(2):758-768
The present paper deals with the application of the classical theory of equilibrium figures of two rotating liquid masses to the case where bodies exhibit a radially stratified internal density distribution so that they can be considered as inhomogeneous bodies. The derived ellipsoidal shape solutions are applied to five real systems of equal-sized synchronous asteroids. Furthermore, internal inhomogeneity puts strong constraints on the surface grain density. A satisfactory model fit is achieved with internal densities of asteroids steadily increasing outwards. In particular, from such an approach we derived grain densities of the considered systems in agreement with their mineralogical composition inferred from reflectance spectroscopy. According to this new approach, 4492 Debussy, presently of unknown spectral type, is predicted to appear as a C-type object with a grain density on the order of 2 g/cm3. 相似文献
1000.
We develop a simple model to explain the non-radial motion of eruptive solar filaments under solar minimum conditions. The global magnetic field is derived from the first and third components of the spherical harmonic expansion of a magnetic scalar potential. The filament is modeled as a toroidal current located above the mid-latitude polarity inversion line. We investigate the stability of the filament against changes in the filament current and attempt to explain the non-radial motion and acceleration of the eruptive filament. We also discuss the limitations of this model. 相似文献