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BORIS SEVRUK 《水文科学杂志》2013,58(2):231-236
ABSTRACT The evaporation losses from the container of an old galvanized Hellmann gauge, 7·1 cm2 aperture area, were five times greater than the losses from the container of a new gauge, 1·8 cm2 aperture area, of almost the same grey colour. The maximum evaporation from the old gauge amounted to 0·75 mm per day. The same evaporation losses in the Baye of Montreux basin over a period of 10 years from April to September amounted to 0·09 mm per measurement or to 0·7 per cent of the precipitation catch. There is a relationship between the monthly percentage evaporation losses and the ratio of evaporation time and rainfall duration (r = 0·803). 相似文献
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中国海与现代科学技术 总被引：5，自引：2，他引：5
中国既是一个大陆国家又是一个海洋国家，约３００万平方公里的海域与６５００多个岛屿如同陆地资源一样为中国人民提供了舟辑之便与渔盐之利，还蕴藏着丰富的矿产资源。 相似文献
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ABSTRACT The purpose of an hydrometric network is to obtain data giving answers to problems raised by the use of water. The methodology suggested in this paper is essentially based on the regional identification of the actual and potential uses of water, on the estimate of the intensity of their use and on the determination of the hydrological characteristics related to this demand. The level of accuracy required for these characteristics is an important feature in the rationalization procedure. The various types of stations are defined according to the purpose of their use and the network considered is on a dynamic basis depending on the evolution of uses. The major results obtained for Quebec by the application of this method are described. 相似文献
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《水文科学杂志》2013,58(2):362-366
Abstract Most commonly used biochemical oxygen demand (BOD) and dissolved oxygen (DO) models have been tested for their applicability in the River Kali, which is one of the most polluted rivers in India. A total of 732 field data sets were generated during field survey from March 1999 to February 2000. The modelling of BOD and DO in the River Kali involves derivation and solution of the governing equations that describe concentration change with time and space brought on by advective, decay, settling and loading functions. However, due to continuous discharges (e.g. from wastewater treatment plants) and steady-state flow conditions in the River Kali, the dispersion effects are found to be insignificant. In the analysis, the model parameters used in BOD-DO models were optimized using the Newton-Raphson technique and the performance of different models was evaluated using correlation statistics (r 2) and error estimation, viz. standard error (SE) and mean multiplicative error (MME). The results indicate that the BOD-DO models developed after Camp (1963) yielded the best agreement with the observed values as compared with several other approaches. 相似文献
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《水文科学杂志》2013,58(3):481-486
Abstract Explicit algebraic expressions of influence coefficients of an aquifer system are addressed. The methodology is straightforwardly exemplified using a one-dimensional (1D) semi-confined homogeneous aquifer model. It consists of the integration of the governing equation from two different viewpoints. On the one hand, the analytical solution to the governing equation is presented under an integral form involving the appropriate Green function. On the other hand, equations resulting from a finite difference discretization are processed to deduce a fully explicit algebraic expression of the nodal hydraulic head. This latter, arranged after the previously developed continuum solution, helps with deriving an explicit algebraic expression of influence coefficients corresponding to the studied aquifer model. Finally, the study is extended to an inhomogeneous aquifer model. 相似文献
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应用文献计量方法，对《湖泊科学》１９８９￣１９９５年出版的２０期所刊２４３篇论文进行统计分析，包括论文分类统计、作者分析、基金论文统计分析等。在分析基础上阐述湖泊科学发展现状以及为期刊编辑、文献工作者提供一个量化的衡量工作的依据。 相似文献
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20世纪地球科学的发展 总被引：15，自引：9，他引：6
20世纪地球科学经历了大陆漂移、海底扩张和岩石层板块大地构造的发展过程 ,通过研究的深化和认识的更新 ,使得许多孤立的地质现象进一步得到规律性的认识 .岩石层板块大地构造理论的基本内涵是活动论 ,查清地球的形成和演化历史 ,才能更深刻地认识它 相似文献