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181.
182.
G. Cayrel de Strobel Y. Lebreton C. Soubiran E.D. Friel 《Astrophysics and Space Science》1999,265(1-4):345-352
The authors of this paper try to disentangle the many problems arisen from a new enlarged sample of nearby low-mass,metal-rich-stars.
These stars have reliable absolute magnitudes, deduced from Hipparcos parallaxes, precise bolometric corrections, effective
temperatures and metal abundances from high resolution detailed spectroscopic analyses. Their ages have been derived from
a grid of isochrones calculated with up to date physics. The main goal of this paper is to determine the ages of the slightly
evolved SMR stars. Among those with well determinated ages about 80% of them have intermediate ages of (2 to 5 Gyr), but only
20% have ages of 8 Gyr or more. Nevertheless, the existence of very old metal-rich stars is confirmed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
183.
Actual surface fields of meteorological variables 1–3 hours before the heavy showers are analyzed in detail for the purpose
of their specification with WRF-ARW model. The complex of hygrothermodynamic characteristics needed for this purpose is discovered.
The detailed satellite, radar, and synoptic data are also considered. 相似文献
184.
Mihail E. Popescu 《Engineering Geology》1979,14(1):43-53
Engineering problems associated with expansive clay formations, which have a large swelling and shrinking potential, exist in different regions of Romania.In the general framework of the study of the behaviour of expansive clays, the present paper describes some particular aspects connected with the swelling and shrinkage processes and their engineering effects in Romania.The differences between swelling potential relationships, obtained by two different methods are presented and discussed. Swelling pressure tests were accomplished using the available standard techniques, as well as a specially developed cell pressure equipment.Attention is drawn to the stages of the shrinkage process as related to soil structure. It was found that, in a general case, there are three distinct?tages: initial, normal and residual shrinkage.Laboratory investigations have shown that in soils with an anisotropic structure, the directional variation of shrinkage strains is elliptical in shape, with the maximum shrinkage normal to particle orientation.The engineering aspects of the results are discussed. 相似文献
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In certain areas of the Namib gravel plains a new Ariadna sp. was discovered. It rims its vertical burrow with a stone circle, made on average of seven quartz stones. Some mathematical relationships between hole diameter, stone sizes and weight, and animal size were studied. A correlation was found, and stone selection by this spider postulated. Different hypotheses on the adaptive value of stone circle are suggested. 相似文献
188.
Wide-angle vibroseis test across the Rhine graben 总被引:1,自引:0,他引:1
B. Damotte K. Fuchs E. Lüschen F. Wenzel R. Schlich G. Toreilles 《Geophysical Journal International》1987,89(1):313-318
Summary. As a joint operation of ECORS and DEKORP, a deep wide-angle seismic experiment using vibrators was carried out in the autumn of 1984. The object was to get information on the deep crust under the Rhine graben without crossing through sedimentary layers. Offsets were in the range of 50 to 89 km. In the first phase, two vibration points were executed in the Vosges mountains. A signal was received in the Black Forest from solely the farthest VP. In the second phase, fourteen VPs were executed in the Black Forest. No stacking or correlation was performed in the field in France. The quality of the results is good only if an equalization is applied before vertical stacking and correlation in the computing centre. 相似文献
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190.
Geography at elementary and middle schools in Louisiana, USA., remains a social studies strand along with civics, economics, and history, with no state-required geography course at any level. But because schools may require more geography than the state standard, this research examines the extent to which K–12 students are exposed to geography in Louisiana, using an electronic survey and an interview with state department of education officials. Results suggest that geography remains underemphasized, but the 2011 implementation of new social studies standards, the Advanced Placement Human Geography course, and other initiatives offer promise for more geographically literate Louisiana citizens. 相似文献