The paper discusses the use of five hydrochemical indexes in evaluating seawater intrusion, and ranking the intrusion degree for Cl -, M, Br -, rHCO 3/rCl and SAR. The fuzzy mathematical comprehensive judgement mo...The paper discusses the use of five hydrochemical indexes in evaluating seawater intrusion, and ranking the intrusion degree for Cl -, M, Br -, rHCO 3/rCl and SAR. The fuzzy mathematical comprehensive judgement model has been adopted as the method of adjustment. Based on more than 300 water samples obtained from four typical profiles in the coastal region of Laizhou Gulf during the period from June 1993 to June 1995, we made a comprehensive judgement of seawater intrusion degree. The result shows that intrusion degree was becoming heavier from June 1993 to June 1994, but more steady and inactive in the high level of intrusion degree in the perennial severe intrusion zone from December 1994 to June 1995. Since entering the 1990s up to now, the process of seawater intrusion has translated from its peak developmental stage from the 1970s to the 1980s into a stage of equilibrium and slow development mainly because the intruded area expanded inland, precipitation increased at some extent recently and various measures of prevention and harness begin to show the effect.展开更多
目的研究真空度对2205双相不锈钢在海水淡化环境中耐点蚀性能的影响。方法在1.5倍人工浓缩海水中,采用循环阳极极化曲线与电化学阻抗谱等电化学方法,研究了2205双相不锈钢的点蚀和再钝化行为,并通过扫描电子显微镜对极化后试样的腐蚀形...目的研究真空度对2205双相不锈钢在海水淡化环境中耐点蚀性能的影响。方法在1.5倍人工浓缩海水中,采用循环阳极极化曲线与电化学阻抗谱等电化学方法,研究了2205双相不锈钢的点蚀和再钝化行为,并通过扫描电子显微镜对极化后试样的腐蚀形貌进行分析。结果测试了七种不同真空状态下2205双相不锈钢的循环阳极极化曲线和电化学阻抗谱,发现随着真空度的升高,试样的自腐蚀电位和点蚀电位均不断降低,分别约从-256 m V和605 m V下降到-485 m V和363 m V(均vs.SCE),点蚀倾向明显增大。同时,Nyquist曲线中的半圆弧逐渐变得扁平,Bode图中的相位角约从80°下降到77°,但是点蚀电位与再钝化电位之差逐渐升高。不同真空度下循环阳极极化后,试样表面的点蚀坑形貌不完全相同,蚀坑数量随着真空度的升高而明显减少,当真空度升高为0.72时,点蚀坑尺寸明显减小。结论随着真空度的逐渐升高,不锈钢钝化膜的致密性和保护性降低,电化学阻抗值逐渐减小,耐点蚀性能变差,但是再钝化性能却有所增强。循环阳极极化后试样的腐蚀程度减小。展开更多
文摘The paper discusses the use of five hydrochemical indexes in evaluating seawater intrusion, and ranking the intrusion degree for Cl -, M, Br -, rHCO 3/rCl and SAR. The fuzzy mathematical comprehensive judgement model has been adopted as the method of adjustment. Based on more than 300 water samples obtained from four typical profiles in the coastal region of Laizhou Gulf during the period from June 1993 to June 1995, we made a comprehensive judgement of seawater intrusion degree. The result shows that intrusion degree was becoming heavier from June 1993 to June 1994, but more steady and inactive in the high level of intrusion degree in the perennial severe intrusion zone from December 1994 to June 1995. Since entering the 1990s up to now, the process of seawater intrusion has translated from its peak developmental stage from the 1970s to the 1980s into a stage of equilibrium and slow development mainly because the intruded area expanded inland, precipitation increased at some extent recently and various measures of prevention and harness begin to show the effect.
文摘目的研究真空度对2205双相不锈钢在海水淡化环境中耐点蚀性能的影响。方法在1.5倍人工浓缩海水中,采用循环阳极极化曲线与电化学阻抗谱等电化学方法,研究了2205双相不锈钢的点蚀和再钝化行为,并通过扫描电子显微镜对极化后试样的腐蚀形貌进行分析。结果测试了七种不同真空状态下2205双相不锈钢的循环阳极极化曲线和电化学阻抗谱,发现随着真空度的升高,试样的自腐蚀电位和点蚀电位均不断降低,分别约从-256 m V和605 m V下降到-485 m V和363 m V(均vs.SCE),点蚀倾向明显增大。同时,Nyquist曲线中的半圆弧逐渐变得扁平,Bode图中的相位角约从80°下降到77°,但是点蚀电位与再钝化电位之差逐渐升高。不同真空度下循环阳极极化后,试样表面的点蚀坑形貌不完全相同,蚀坑数量随着真空度的升高而明显减少,当真空度升高为0.72时,点蚀坑尺寸明显减小。结论随着真空度的逐渐升高,不锈钢钝化膜的致密性和保护性降低,电化学阻抗值逐渐减小,耐点蚀性能变差,但是再钝化性能却有所增强。循环阳极极化后试样的腐蚀程度减小。
