排序方式: 共有28条查询结果,搜索用时 343 毫秒
21.
Ewan W. Anderson 《GeoJournal》1995,37(2):225-228
With the changing nature of what can be defined as security and the more widely ranging role of the military, the concept of the operational environment has been vastly enhanced. At the same time, the focus with regard to conflict has moved from a potential global nuclear war to conventional regional or local encounters. As a result, considerations of the fundamental environments in which the three armed services operate have become more prominent. In response to these changes, the aim of the paper is to review the various bases for the study of the military operational environment, while placing the emphasis upon conflict and the physical environment. 相似文献
22.
23.
Ewan W. Anderson 《GeoJournal》1994,34(2):201-205
The increasing range and occurrence of disasters has generated global concern. At the same time, the end of the Cold War has resulted in a re-orientation of military thinking. As the role of the military is being redefined, one focus has been upon the potential contribution of disaster relief. In this paper, the complexity of disasters is examined and then the military capability is discussed and illustrated. 相似文献
24.
Rmi Coltat Yannick Branquet Pierre Gautier Hector Campos Rodriguez Marc Poujol Ewan Pelleter Sean McClenaghan Gianreto Manatschal Philippe Boulvais 《地学学报》2019,31(6):549-561
Mid‐Ocean Ridges host various types of hydrothermal systems including high‐T black‐smokers found in ultramafic rocks exhumed along slow spreading ridges. These systems are mostly described in two dimensions as their exposure on the present‐day seafloor lacks the vertical dimension. One way to understand these systems at depth is to study their fossilized equivalents preserved on‐land. Such observation can be done in the Platta nappe, Switzerland, where a Jurassic‐aged mineralized system is exposed in 3D. Serpentinites host a Cu‐Fe‐Ni‐Co‐Zn‐rich mineralization made of sulphides, magnetite and Fe‐Ca‐silicates either replacing serpentinites or within stockwork. Fe‐Ca‐silicates, abundant at the deepest levels, vanish in the mineralization close to the palaeo‐detachment. Fluids were channelized along mafic dykes and sills acting as preferential drains. Warm carbonation (~130°C) is the latest hydrothermal record. We propose that this system is an analog to the root zone of present‐day serpentinite‐hosted hydrothermal systems such as those found along the Mid‐Atlantic Ridge. 相似文献
25.
The relation between X-ray luminosity and near-infrared (NIR) luminosity for early-type galaxies has been examined. NIR luminosities should provide a superior measure of stellar mass compared to optical luminosities used in previous studies, especially if there is significant star formation or dust present in the galaxies. However, we show that the X-ray–NIR relations are remarkably consistent with the X-ray–optical relations. This indicates that the large scatter of the relations is dominated by scatter in the X-ray properties of early-type galaxies, and is consistent with early-types consisting of old, quiescent stellar populations.
We have investigated scatter in terms of environment, surface brightness profile, Mg2 , Hβ, Hγ line strength indices, spectroscopic age and nuclear Hα emission. We found that galaxies with high Mg2 index, low Hβ and Hγ indices or a 'core' profile have a large scatter in L X , whereas galaxies with low Mg2 , high Hβ and Hγ indices or 'power-law' profiles generally have L X < 1041 erg s−1 . There is no clear trend in the scatter with environment or nuclear Hα emission. 相似文献
We have investigated scatter in terms of environment, surface brightness profile, Mg
26.
Ewan W. Anderson 《GeoJournal》1997,41(2):111-114
With such a limited area and range of rock type, Malta cannot provide anything approaching a representative sample of the landforms which occur in the Mediterranean Basin. However, few geomorphological features can be considered unique to the Mediterranean, since they are shared either by the more humid temperate climates to the north or the semi-arid regions to the south and east. The wied, a hybrid between the humid temperate and semi-arid climates, might be considered a truly Mediterranean landform and is the predominant feature in Maltese geomorphology. 相似文献
27.
28.