PCG2 （Preconditioned Conjugate-Gradient Method 2）, the most popular mothod used in groundwater field, was used to solve the distributed model of large-scale groundwater system. Its principle and effect was analyzed ...PCG2 （Preconditioned Conjugate-Gradient Method 2）, the most popular mothod used in groundwater field, was used to solve the distributed model of large-scale groundwater system. Its principle and effect was analyzed mathematically, and verified by some specific examples. Numerical results acquired by PCG2 are accurate, it demonstrates that PCG2 is effective on methodology itself and man-ralated operation. So PCG2 is worthy of popularizing in the area of groundwater system for numerical analysis.展开更多
为探究聚乙烯醇(PVA)纤维对粉煤灰-矿渣基地聚物抗硫酸盐侵蚀性能的影响,对掺入不同纤维长度及体积掺量的PVA纤维增强地聚物进行硫酸盐干湿循环侵蚀试验,分析了硫酸盐侵蚀前后试件的质量及抗压强度变化规律;利用灰色系统理论,建立硫酸...为探究聚乙烯醇(PVA)纤维对粉煤灰-矿渣基地聚物抗硫酸盐侵蚀性能的影响,对掺入不同纤维长度及体积掺量的PVA纤维增强地聚物进行硫酸盐干湿循环侵蚀试验,分析了硫酸盐侵蚀前后试件的质量及抗压强度变化规律;利用灰色系统理论,建立硫酸盐干湿循环作用下PVA纤维增强地聚物抗压强度GM(1,1)预测模型。研究结果表明:掺入适量PVA纤维能有效提升试件抗硫酸盐侵蚀性能,但掺入过量则会起反作用,在本研究9个配比方案中,加入体积掺量为0.10%的18 mm PVA纤维时效果最佳;采用建立的GM(1,1)模型对试件抗压强度进行预测,在纤维体积掺量不超过0.20%时具有较高精度。展开更多
文章以幂函数变换为研究对象,从背景值误差和还原误差的角度分析了幂函数变换对GM(1,1)模型建模精度的影响,论证了幂函数变换的GM(1,1)模型(PFNGM(1,1)模型)具有逼近无偏性,能在可忽略的误差范围内实现对白指数序列的预测无偏性。实例...文章以幂函数变换为研究对象,从背景值误差和还原误差的角度分析了幂函数变换对GM(1,1)模型建模精度的影响,论证了幂函数变换的GM(1,1)模型(PFNGM(1,1)模型)具有逼近无偏性,能在可忽略的误差范围内实现对白指数序列的预测无偏性。实例应用结果表明,其建模精度和预测效果均优于无偏GM(1,1)模型和离散GM(1,1)模型。为将适宜建模序列拓展至近似非齐次指数序列和季节波动序列,同时保留幂函数变换可以有效降低背景值误差对建模精度影响的优势,将幂函数变换与平移变换相结合构建了PFNGM(1,1)模型,将幂函数变换与季节性GM(1,1)模型(SGM(1,1)模型)相结合构建了PFSGM(1,1)模型。实例应用结果表明,PFNGM(1,1)模型的建模精度和预测效果均优于背景值改进的NGM(1,1, k )模型和ONGM(1,1, k,c )模型,PFSGM(1,1)模型的建模精度和预测效果均优于SGM(1,1)模型,验证了两种模型的有效性。展开更多
基金Supported by National Natural Science Foundation (30370825)
文摘PCG2 （Preconditioned Conjugate-Gradient Method 2）, the most popular mothod used in groundwater field, was used to solve the distributed model of large-scale groundwater system. Its principle and effect was analyzed mathematically, and verified by some specific examples. Numerical results acquired by PCG2 are accurate, it demonstrates that PCG2 is effective on methodology itself and man-ralated operation. So PCG2 is worthy of popularizing in the area of groundwater system for numerical analysis.
文摘为探究聚乙烯醇(PVA)纤维对粉煤灰-矿渣基地聚物抗硫酸盐侵蚀性能的影响,对掺入不同纤维长度及体积掺量的PVA纤维增强地聚物进行硫酸盐干湿循环侵蚀试验,分析了硫酸盐侵蚀前后试件的质量及抗压强度变化规律;利用灰色系统理论,建立硫酸盐干湿循环作用下PVA纤维增强地聚物抗压强度GM(1,1)预测模型。研究结果表明:掺入适量PVA纤维能有效提升试件抗硫酸盐侵蚀性能,但掺入过量则会起反作用,在本研究9个配比方案中,加入体积掺量为0.10%的18 mm PVA纤维时效果最佳;采用建立的GM(1,1)模型对试件抗压强度进行预测,在纤维体积掺量不超过0.20%时具有较高精度。
文摘文章以幂函数变换为研究对象,从背景值误差和还原误差的角度分析了幂函数变换对GM(1,1)模型建模精度的影响,论证了幂函数变换的GM(1,1)模型(PFNGM(1,1)模型)具有逼近无偏性,能在可忽略的误差范围内实现对白指数序列的预测无偏性。实例应用结果表明,其建模精度和预测效果均优于无偏GM(1,1)模型和离散GM(1,1)模型。为将适宜建模序列拓展至近似非齐次指数序列和季节波动序列,同时保留幂函数变换可以有效降低背景值误差对建模精度影响的优势,将幂函数变换与平移变换相结合构建了PFNGM(1,1)模型,将幂函数变换与季节性GM(1,1)模型(SGM(1,1)模型)相结合构建了PFSGM(1,1)模型。实例应用结果表明,PFNGM(1,1)模型的建模精度和预测效果均优于背景值改进的NGM(1,1, k )模型和ONGM(1,1, k,c )模型,PFSGM(1,1)模型的建模精度和预测效果均优于SGM(1,1)模型,验证了两种模型的有效性。
