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After systemic investigation of the techniques���route lines and mechanisms about the remaining oil���the dynamic migration and congregation behavior of the remaining oil are discussed on base of interaction between flowing and enriching of water and oil.After the micro-scope modeling of the fluid flow in porous media and the changes in petrol-physical properties of the flowing system, the characters of fluid fields and the dynamic distribution of oil are discussed, among which the preference-flowing is focused on. Based on the preference-flowing in porous media, the concept of the preference-flowing channels is developed. According to above, heterogeneous distribution of water and oil in the field and dynamic mechanism of remaining oil are all obvious. media can be divided into three kinds, directional, stochastic, arbitrary porous media. The main research results are as following: 1. Treating the characteristic parameters such as permeability, porosity and wettability as regional parameter, the fluid field with high water-cut has been established by geostatistical method, among which the difference of flowing pores and the changes of its petrol-physical properties during flooding are studied. 2. The flow process of water and oil are recurrent in physical simulation experiments, in which the mechanisms and phenomena are caught and analyzed. Fluid flow mechanics in porous media with preference-flowing channels have been studied. 3. The mutual coupling between water and oil is induced and the mathematical evolution equations including this interaction were built. . 4. Through coupling effect between flowing water and oil, the dynamic migration and congregation behavior of remaining oil depend upon this coupling. 5. Coupling between water and oil act as driving force and trapping force for the remaining oil. The coupling model of thesis has been verified by simplified the numerical model and compared results with Ng35 oil reservoir in Gudao oil field, it has important theoretical and application values for improving precision of remaining oil and production performance prediction, and is a new method for studying the mechanics of remaining oil in channeled porous media has been established. Key words���flow field���high water-cut���coupling���dominant flow in porous media���remaining oil

Age-dependence of urinary normal and modified nucleosides in childhood as determined by reversed-phase high-performance liquid chromatography

Modified nucleosides have been characterized as tumor markers for a number of malignant diseases. In order to use these markers in children, the age-dependence of the nucleoside levels in healthy children has to be established and taken into account in diagnostic decisions. In this study, the levels of 12 normal and modified nucleosides in urine of 166 healthy children and adolescents with an age between 1 day and 19 years are determined by reversed-phase HPLC, and age-dependent reference ranges are defined. The urinary nucleoside concentrations are related to the creatinine concentrations, which allows the use of randomly collected urine samples. All nucleoside levels in urine of children decrease with age, most pronounced during the first 4 years of life, and the age-dependence of the reference values of the individual nucleosides can be approximated by a mathematical function y = b(0) + b(1) (1/x) with the regression coefficients b(0) and b(1), the nucleoside levels y and the age x between 1 year and 19 years. In the very young children, the shifts in the nucleoside concentrations are more differentiated. Starting with low levels on the first day of life, the concentrations of all studied nucleosides rise up to an age of 1-2 months, when they reach their absolute maximum for all age periods, and then decrease. (C) 2004 Elsevier B.V. All rights reserved.