Fault mechanisms from near-source data: joint inversion of S polarizations and P polarities     

Aldo Zollo  Pascal Bernard 《Geophysical Journal International》1991,104(3):441-451

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Flickering in the Magnetic Cv Star Am Herculis     

Belinda Kalomeni  E. Rennan PekÜnlÜ  Kadri Yakut 《Astrophysics and Space Science》2005,296(1-4):477-480

In this study, we present a photometric study of AM Her, a prototype of a class of magnetic CVs. Optical photometry of AM Her was obtained using the Russian–Turkish 1.5 m telescope at TüBİTAK National Observatory (TUG) in August 2003. The R band light curve of the system shows two maxima and two minima during one orbital cycle. In both observing nights the star showed flickering at a significant level. The measured flickering time scale is about 5 min.  相似文献   

One hundred years of mountain hydrology in Switzerland by the WSL     

Christoph Hegg  Brian W. McArdell  Alexandre Badoux 《水文研究》2006,20(2):371-376

In 1903 the Swiss Federal Research Institute WSL started its first forest hydrology measurements with the aim to deliver a sound scientific basis for the implementation of new forest legislation introduced in Switzerland in 1876. This legislation was triggered by several large floods that occurred in Switzerland, for which a major cause was widely seen as the poor condition of forests at that time. Consequently, hydrologic research at WSL first focused on the influence of forests on floods. In the second half of the 20th century, other hydrological issues such as water quality, snow hydrology and sediment transport complemented the hydrologic research at WSL. Some recent results of this work are presented in three papers joining this introductory paper to mark the 100th anniversary of hydrologic research at WSL. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Geo-effectiveness of solar wind extremes     

Hari Om Vats 《Journal of Astrophysics and Astronomy》2006,27(2-3):227-235

Examples of extreme events of solar wind and their effect on geomagnetic conditions are discussed here. It is found that there are two regimes of high speed solar wind streams with a threshold of ∼ 850 km s^-1. Geomagnetic activity enhancement rate (GAER) is defined as an average increase in Ap value per unit average increase in the peak solar wind velocity (Vp) during the stream. GAER was found to be different in the two regimes of high speed streams with +ve and-ve IMF. GAER is 0.73 and 0.53 for solar wind streams with +ve and -ve IMF respectively for the extremely high speed streams (< 850 km s^-1). This indicates that streams above the threshold speed with +ve IMF are 1.4 times more effective in enhancing geomagnetic activity than those with -ve IMF. However, the high speed streams below the threshold with -ve IMF are 1.1 times more effective in enhancing geomagnetic activity than those with +ve IMF. The violent solar activity period (October–November 2003) of cycle 23 presents a very special case during which many severe and strong effects were seen in the environment of the Earth and other planets; however, the z-component of IMF (Bz) is mostly positive during this period. The most severe geomagnetic storm of this cycle occurred when Bz was positive.  相似文献   

Tests and constraints on theories of galaxy formation and evolution     

Rodger I. Thompson 《Astrophysics and Space Science》2003,284(2):353-356

Tests and constraints on current theories of galaxy formation and evolution are presented. They are derived from observations of the Northern Hubble Deep Field with WFPC2 and NICMOS. Photometric redshifts, extinctions and spectral energy distributions are calculated for all objects in the field. The tests and constraints are derived from the output of this analysis. The tests of the predictions from hierarchical and pure luminosity evolution galaxy evolution calculations favor the hierarchical model. Constraints are provided by the current luminosity function and its evolution to a redshift of 6. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

海拉尔盆地乌尔逊凹陷古流体动力场数值模拟   总被引：5，自引：0，他引：5  

杨金侠 《地球科学与环境学报》2003,25(3):41-47

首先对地下水动力场进行数学描述,以水动力为主线,建立适合该地区的数学模型,选择正确的地质模型参数,主要采用数值计算和模拟等手段,在恢复出乌尔逊凹陷主要目的层在不同地质历史时期古水动力的基础上又恢复出古流体势的演化历史。整体上,在乌尔逊凹陷,各主要地质时期的油势演化特征为西部地区大于东部地区,乌南大于乌北,且低势区的发育有较好的继承性。最后,依据油气聚集理论,进行油气运移聚集系统的划分、油气运移方向的分析,从而得出有关研究区油气运移聚集条件的认识,主要从流体动力的角度考虑,指出有利聚集区,认为在乌尔逊凹陷苏4～苏18井区、苏132～苏17～铜2井区及巴1～巴2～巴4井区为有利油气运移聚集区。  相似文献   

The Ancash, Peru, earthquake of 1946 November 10: evidence for low-angle normal faulting in the high Andes of northern Peru     

Diane I. Doser 《Geophysical Journal International》1987,91(1):57-71

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RELAXING ASSUMPTIONS OF PERFECT INFORMATION IN PARK VISITATION MODELS*     

Daniel J. Stynes  Daniel M. Spotts  John R. Strunk 《The Professional geographer》1985,37(1):21-28

Variables related to urban park awareness are identified and methods for relaxing assumptions of perfect information in park use models are discussed. Park awareness is related to park characteristics (age and degree of development of the park), population characteristics (race, age, length of residence, recreation participation), and distance. Park attributes are stronger predictors of both park awareness and use than is distance. These findings parallel similar research on the cognitive aspects of shopping decisions.  相似文献   

临猗5.0级地震前后品质因子值变化特征研究     

王卫东  张永志  杜长娥 《地球科学与环境学报》2005,27(1):70-71,79

利用西安数字地震遥测台网记录的数字地震资料，采用P波初动半周期残差法求得1998年7月临猗5．0级地震前后不同路径的Q(品质因子)值变化，发现在地震发生前Q值为87～203，震后Q值为67～164，震前震中区附近出现明显的高Q值异常。结果表明，地震前的高Q值异常可以作为地震预测的一种手段。  相似文献   

时空概念中的椭球改正     

夏哲仁 《测绘学报》1991,20(3):190-200

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