排序方式： 共有18条查询结果，搜索用时 15 毫秒
11.
E. Sahnoun C. Nkem A. Naindouba K. Hammami N. Jaïdane L. C. Owono Owono 《Astrophysics and Space Science》2018,363(9):195
We present new two- and four-dimensional potential energy surfaces for the KCl(\(\mbox{X}^{1} \varSigma ^{+}\))-He and KCl(\(\mbox{X}^{1} \varSigma ^{+}\))-para-H2 systems calculated with the internuclear distances of KCl and H2 frozen at their experimental minimum energy. The CCSD(T) level of theory with aug-cc-pVQZ/AQZP basis sets is used. The potential surfaces present well depths of about \(78~\mbox{cm}^{-1}\) and \(235~\mbox{cm}^{-1}\) below the dissociation limit of the above interacting systems respectively. With these potential surfaces, cross sections are obtained in the close coupling scheme and rate coefficients inferred by averaging the cross sections over a Maxwell-Boltzmann velocity distribution for temperature below 50 K. A propensity towards \(\Delta J = 1\) transitions is observed. 相似文献
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The former agro-pastoral system which prevailed in the Tunisian Sahara had developed a pastoral resource management which preserved the rather fragile ecological equilibrium. Nowadays in the Tunisian Sahara nearly all former nomads are settled around the villages and irrigated areas which were created with the official aim of utilizing the Sahara. The sedentarization of the nomads has provoked two phenomena: a concentration and an increased density of population around the newly founded oases on the one hand and a depopulation of the more remote steppes on the other hand. Actually this demographic disequilibrium threatens the ecological equilibrium which existed in the past. It has caused a multiplication of the stocking of the actual pastures and increases the risk of degradation of the peripheral and easily accessible grazing-grounds. It exercises an excessive pressure on the environment through the intensive human activities and the satisfaction of new needs. This pressure manifests itself in the enlargement of the circles of degradation around the oases and the intensification of aeolian dynamics. A regeneration of the former organically developed eco-system is impossible without conscious reference into the local traditions and without consideration of the complexity of interelationship of the various factors. 相似文献
13.
Ridha Abdessalem Gharbi Lassaâd Chihi Mongi Hammami Abdelkader Soumaya Ali Kadri 《Comptes Rendus Geoscience》2005,337(14):1293-1300
The geodynamic evolution of the diapir of Zag Et Tir is the result of the coexistence of the diapiric and tectonic activity from the Upper Cretaceous until the Quaternary. The interference of the tectonic and diapiric phenomena is at the origin of the basin individualization with differential sedimentation during the Miocene. This explains the current distribution of the Neogene deposits on both sides of Zag Et Tir Triassic structure. The submeridian faults that subdivide our sector played a significant role during the Atlasic compression, inducing an unequal distribution of the folds on both sides of these accidents, as well in kind as in number, showing the anteriority of the faults compared to the folds. To cite this article: R.A. Gharbi et al., C. R. Geoscience 337 (2005). 相似文献
14.
Evidence for Triassic salt domes in the Tunisian Atlas from gravity and geological data 总被引：3，自引：1，他引：3
Chokri Jallouli Mongi Chikhaoui Ahmed Braham Mohamed Moncef Turki Kevin Mickus Ramdhane Benassi 《Tectonophysics》2005,396(3-4):209-225
Detailed gravity data were analyzed to constrain two controversial geological models of evaporitic structures within the Triassic diapiric zone (Triassic massifs of Jebel Debadib and Ben Gasseur) of the northern Tunisian Atlas. Based on surface observations, two geological models have been used to explain the origin of the Triassic evaporitic bodies: (1) salt dome/diapiric structure or (2) a “salt glacier”. The gravity analysis included the construction of a complete Bouguer gravity anomaly map, horizontal gravity gradient (HGG) map and two and a half-dimensional (2.5D) forward models. The complete Bouguer gravity anomaly map shows a prominent negative anomaly over the Triassic evaporite outcrops. The HGG map showed the location of the lateral density changes along northeast structural trends caused by Triassic/Cretaceous lithological differences. The modeling of the complete Bouguer gravity anomaly data favored the diapiric structure as the origin of the evaporitic bodies. The final gravity model constructed over Jebel Debadib indicates that the Triassic evaporitic bodies are thick and deeply rooted involving a dome/diapiric structure and that the Triassic material has pulled upward the younger sediment cover by halokinesis. Taking in account kinematic models and the regional tectonic events affecting the northern margin of Africa, the above diapirs formed during the reactive to active to passive stages of continental margin evolution with development of sinks. Otherwise, this study shows that modeling of detailed gravity data adds useful constraints on the evolution of salt structures that may have an important impact on petroleum exploration models. 相似文献
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Nadjinangar Gotoum Christophe Nkem Kamel Hammami M. Ahamat?Charfadine L. C. Owono?Owono Nejm-Eddine Jaidane 《Astrophysics and Space Science》2011,332(1):209-217
We report on the calculation of collision induced rotational excitation cross sections and rate coefficients of AlF by He
atom at low temperature. These quantities were obtained by first computing the interaction potential energy surface (PES)
of the AlF(X
1Σ+)-He(1
S) van der Waals complex at the ab initio Coupled Cluster with Single and Double and perturbative Triple excitations [CCSD(T)] level of theory. The aug-cc-pVQZ Gaussian
basis, to which was added a set of bond functions, was used for that purpose. The calculations account for basis set superposition
errors (BSSE). The interaction potential presents a minimum of ∼24 cm−1 below the AlF-He dissociation limit. The PES was fitted on a basis of Legendre polynomial functions to allow for the calculation
of cross sections in the close-coupling (CC) approach. By averaging these cross sections over a Maxwell-Boltzmann velocity
distribution, rate coefficients were inferred at low temperatures (T≤300 K). From our computations, a propensity towards ΔJ=1 transitions is observed. 相似文献
17.
Mongi Chikhaoui 《Comptes Rendus Geoscience》2004,336(12):1131-1136
During the Neogene, the sedimentary succession changed from marine shallow water formations during the Early and Middle Miocene to lagoonal and continental formations during the Late Miocene and the Pliocene. This succession is subdivided into three sedimentary major cycles that are mainly due to compressional tectonic events. Propagating folds above a detachment within the evaporitic Triassic strata caused the formation of the tectonics. To cite this article: M. Chikhaoui, C. R. Geoscience 336 (2004). 相似文献
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