分析了K. J. Willam等提出的五参数混凝土破坏准则存在的问题,提出了一个改进了的五参数混凝土破坏准则.这个准则克服了K. J. Willam等的准则的主要缺点,简化了偏斜截面的表达式.准则包含的参数确定方便,与实验数据符合良好,是一个比较...分析了K. J. Willam等提出的五参数混凝土破坏准则存在的问题,提出了一个改进了的五参数混凝土破坏准则.这个准则克服了K. J. Willam等的准则的主要缺点,简化了偏斜截面的表达式.准则包含的参数确定方便,与实验数据符合良好,是一个比较合理的适合钢筋混凝土有限元分析采用的混凝土破坏准则.展开更多
A single diode model for a photovoltaic solar module is the most ideal and quick way of analyzing the module characteristics before implementing them in a solar plant. Solar modules manufacturers provide information f...A single diode model for a photovoltaic solar module is the most ideal and quick way of analyzing the module characteristics before implementing them in a solar plant. Solar modules manufacturers provide information for three critical points that are essential in I-V, P-V or P-I curves. In this study, we propose four separate simulation procedures to estimate the five-model parameters of an analogous single diode equivalent circuit by utilizing three cardinal points of the photovoltaic module I-V curve, described from experimental data using a solar simulator and manufacturer’s datasheet. The main objective is to extract and use the five unknown parameters of a single diode model to describe the photovoltaic system using I-V ad P-V plots under different environmental conditions. The most influential parameters that greatly alter the cardinal points defined at short circuit point (SCP), the maximum power point (MPP) and the open circuit point(OCP) are the ideality factor (</span><i><span style="font-family:Verdana;">n</span></i><span style="font-family:Verdana;">) and the diode saturation current (</span><i><span style="font-family:Verdana;">I<sub>o</sub></span></i><span style="font-family:Verdana;">). For a quick and fast convergence, we have determined the optimal ideality factor (</span><i><span style="font-family:Verdana;">n<sub>o</sub></span></i><span style="font-family:Verdana;">) and optimal saturation current (</span><i><span style="font-family:Verdana;">I<sub>oopt</sub></span></i><span style="font-family:Verdana;">) as the primary parameters by first assuming the optimal values of </span><i><span style="font-family:Verdana;">R<sub>sh</sub></span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">R<sub>s</sub> </span></i><span style="font-family:Verdana;">and </span><i><span style="font-family:Verdana;">I<sub>ph</sub> </span></i><span style="font-family:Verdana;">at standard test conditions (STC). Further, we evaluated the effects of </span><i><span style="font-family:V展开更多
In order to improve reservoir fluid recognition, the sensitivity of array resistivity response to the difference of the invasion properties in both oil-bearing layers and water layers is analyzed. Then the primary inv...In order to improve reservoir fluid recognition, the sensitivity of array resistivity response to the difference of the invasion properties in both oil-bearing layers and water layers is analyzed. Then the primary inversion is carried out based on the array resistivity log. The mud invasion process is numerically simulated based on the oil-water flow equation and water convection diffusion equation. The results show that the radial resistivity of a fresh mud-invaded oil-bearing layer presents complex distribution characteristics, such as nonlinear increase, increasing to decreasing and low resistivity annulus, and the resistive invasion profile of a water layer is monotonic. Under specific conditions, array resistivity log can reflect these changes and the array induction log is more sensitive. Nevertheless, due to the effect of factors like large invasion depth, reservoir physical and oil-bearing properties, the measured apparent resistivity may differ greatly from the actual mud filtrate invasion profile in an oil-bearing layer. We proposed a five-parameter formation model to simulate the complex resistivity distribution of fresh mud-invaded formation. Then, based on the principle of non-linear least squares, the measured array resistivity log is used for inversion with the Marquardt method. It is demonstrated that the inverted resistivity is typically non-monotonic in oil-bearing layers and is monotonic in water layers. Processing of some field data shows that this is helpful in achieving efficient reservoir fluid recognition.展开更多
文摘分析了K. J. Willam等提出的五参数混凝土破坏准则存在的问题,提出了一个改进了的五参数混凝土破坏准则.这个准则克服了K. J. Willam等的准则的主要缺点,简化了偏斜截面的表达式.准则包含的参数确定方便,与实验数据符合良好,是一个比较合理的适合钢筋混凝土有限元分析采用的混凝土破坏准则.
文摘A single diode model for a photovoltaic solar module is the most ideal and quick way of analyzing the module characteristics before implementing them in a solar plant. Solar modules manufacturers provide information for three critical points that are essential in I-V, P-V or P-I curves. In this study, we propose four separate simulation procedures to estimate the five-model parameters of an analogous single diode equivalent circuit by utilizing three cardinal points of the photovoltaic module I-V curve, described from experimental data using a solar simulator and manufacturer’s datasheet. The main objective is to extract and use the five unknown parameters of a single diode model to describe the photovoltaic system using I-V ad P-V plots under different environmental conditions. The most influential parameters that greatly alter the cardinal points defined at short circuit point (SCP), the maximum power point (MPP) and the open circuit point(OCP) are the ideality factor (</span><i><span style="font-family:Verdana;">n</span></i><span style="font-family:Verdana;">) and the diode saturation current (</span><i><span style="font-family:Verdana;">I<sub>o</sub></span></i><span style="font-family:Verdana;">). For a quick and fast convergence, we have determined the optimal ideality factor (</span><i><span style="font-family:Verdana;">n<sub>o</sub></span></i><span style="font-family:Verdana;">) and optimal saturation current (</span><i><span style="font-family:Verdana;">I<sub>oopt</sub></span></i><span style="font-family:Verdana;">) as the primary parameters by first assuming the optimal values of </span><i><span style="font-family:Verdana;">R<sub>sh</sub></span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">R<sub>s</sub> </span></i><span style="font-family:Verdana;">and </span><i><span style="font-family:Verdana;">I<sub>ph</sub> </span></i><span style="font-family:Verdana;">at standard test conditions (STC). Further, we evaluated the effects of </span><i><span style="font-family:V
基金funded by the National Natural Science Foundation (41174009)National Major Science &Technology Projects (2011ZX05020, 2011ZX05035,2011ZX05003, 2011ZX05007)
文摘In order to improve reservoir fluid recognition, the sensitivity of array resistivity response to the difference of the invasion properties in both oil-bearing layers and water layers is analyzed. Then the primary inversion is carried out based on the array resistivity log. The mud invasion process is numerically simulated based on the oil-water flow equation and water convection diffusion equation. The results show that the radial resistivity of a fresh mud-invaded oil-bearing layer presents complex distribution characteristics, such as nonlinear increase, increasing to decreasing and low resistivity annulus, and the resistive invasion profile of a water layer is monotonic. Under specific conditions, array resistivity log can reflect these changes and the array induction log is more sensitive. Nevertheless, due to the effect of factors like large invasion depth, reservoir physical and oil-bearing properties, the measured apparent resistivity may differ greatly from the actual mud filtrate invasion profile in an oil-bearing layer. We proposed a five-parameter formation model to simulate the complex resistivity distribution of fresh mud-invaded formation. Then, based on the principle of non-linear least squares, the measured array resistivity log is used for inversion with the Marquardt method. It is demonstrated that the inverted resistivity is typically non-monotonic in oil-bearing layers and is monotonic in water layers. Processing of some field data shows that this is helpful in achieving efficient reservoir fluid recognition.
