The corrosion behaviors of Al-6Mg-Zr and Al-6Mg-Zr-Sc in the sulfate-reducing bacteria （SRB） solution in anaerobic environment were studied using electrochemical, microbiological, and surface analysis methods. It wa...The corrosion behaviors of Al-6Mg-Zr and Al-6Mg-Zr-Sc in the sulfate-reducing bacteria （SRB） solution in anaerobic environment were studied using electrochemical, microbiological, and surface analysis methods. It was found that the oxide film was more compact owing to the addition of Sc resulting in the open circuit potential shifting by about 100mV positively. On the other hand, it was seen that the pitting sensitivity of Al-6Mg-Zr-Sc alloy in SRB solution decreased and its microbiologically influenced corrosion resistance was improved. Pitting corrosion occurring on the surface of the two alloys under the comprehensive action of the metabolism of SRB was observed by SEM. It was obtained by EDS that the corrosion degree increased with time and corrosion was furthered by deposition of the product.展开更多
利用元胞自动机模型进行城市扩张模拟时,其使用的栅格数据格式和基于统计的转换规则提取方法必然会导致可变面积单元问题(the Modifiable Areal Unit Problem,MAUP)的出现。采用系统的敏感性分析方法对该问题的粒度效应、划区效应和综...利用元胞自动机模型进行城市扩张模拟时,其使用的栅格数据格式和基于统计的转换规则提取方法必然会导致可变面积单元问题(the Modifiable Areal Unit Problem,MAUP)的出现。采用系统的敏感性分析方法对该问题的粒度效应、划区效应和综合效应进行了分析,研究表明:1)MAUP问题在CA模拟时是客观存在的,且会对模拟结果造成影响,研究时不能忽视该问题。应进行系统的敏感性分析,获取其对研究问题的影响,寻找适宜的研究粒度和分区方案。2)该研究中粒度效应会呈现明显的尺度阈值,尺度域内的拟合优度和模拟精度较为稳定。尺度阈值在最精细粒度后随即出现,且该阈值与景观指数的尺度阈值一致,反映了景观对象大小对城市扩张模拟的重要影响。3)良好的划区方案能够提高拟合优度和模拟精度,其划区方案应使区域内城市扩张规律差异最小,区域间城市扩张规律差异最大。在大尺度城市扩张模拟时更应采用合理的划区方案以提高模拟精度。4)粒度效应和划区效应的综合影响表现为各区域模型的拟合优度和模拟精度在粒度范围内所受到的影响存在差异,但大多数区域都较为明显地表现出相同的尺度阈值。展开更多
介绍了La Fe M(M=Al,Si)化合物在磁热性能研究方面的最新进展。具有NaZn13型晶体结构,含高浓度Fe的La Fe M(M=Al,Si)化合物为良好的软磁材料;用少量的Co替代化合物中Si,Al元素可以将化合物的居里温度提高至室温;对La(Fe1-yCoy)xSi13-x...介绍了La Fe M(M=Al,Si)化合物在磁热性能研究方面的最新进展。具有NaZn13型晶体结构,含高浓度Fe的La Fe M(M=Al,Si)化合物为良好的软磁材料;用少量的Co替代化合物中Si,Al元素可以将化合物的居里温度提高至室温;对La(Fe1-yCoy)xSi13-x化合物,适量的Si,Co组合可使化合物在室温产生可与Gd5Si2Ge2比拟的磁热效应;加入适量的间隙原子H,也可使La(FexSi1-x)13在室温的磁热性能远远大于金属Gd;对含Si量低及含Si量高的La(FexSi1-x)13化合物在相转变点附近由温度和磁场诱导相变的本质做了详细阐述。展开更多
基金Project supported by the National Natural Science Foundation of China (50571003)
文摘The corrosion behaviors of Al-6Mg-Zr and Al-6Mg-Zr-Sc in the sulfate-reducing bacteria （SRB） solution in anaerobic environment were studied using electrochemical, microbiological, and surface analysis methods. It was found that the oxide film was more compact owing to the addition of Sc resulting in the open circuit potential shifting by about 100mV positively. On the other hand, it was seen that the pitting sensitivity of Al-6Mg-Zr-Sc alloy in SRB solution decreased and its microbiologically influenced corrosion resistance was improved. Pitting corrosion occurring on the surface of the two alloys under the comprehensive action of the metabolism of SRB was observed by SEM. It was obtained by EDS that the corrosion degree increased with time and corrosion was furthered by deposition of the product.
文摘利用元胞自动机模型进行城市扩张模拟时,其使用的栅格数据格式和基于统计的转换规则提取方法必然会导致可变面积单元问题(the Modifiable Areal Unit Problem,MAUP)的出现。采用系统的敏感性分析方法对该问题的粒度效应、划区效应和综合效应进行了分析,研究表明:1)MAUP问题在CA模拟时是客观存在的,且会对模拟结果造成影响,研究时不能忽视该问题。应进行系统的敏感性分析,获取其对研究问题的影响,寻找适宜的研究粒度和分区方案。2)该研究中粒度效应会呈现明显的尺度阈值,尺度域内的拟合优度和模拟精度较为稳定。尺度阈值在最精细粒度后随即出现,且该阈值与景观指数的尺度阈值一致,反映了景观对象大小对城市扩张模拟的重要影响。3)良好的划区方案能够提高拟合优度和模拟精度,其划区方案应使区域内城市扩张规律差异最小,区域间城市扩张规律差异最大。在大尺度城市扩张模拟时更应采用合理的划区方案以提高模拟精度。4)粒度效应和划区效应的综合影响表现为各区域模型的拟合优度和模拟精度在粒度范围内所受到的影响存在差异,但大多数区域都较为明显地表现出相同的尺度阈值。
文摘介绍了La Fe M(M=Al,Si)化合物在磁热性能研究方面的最新进展。具有NaZn13型晶体结构,含高浓度Fe的La Fe M(M=Al,Si)化合物为良好的软磁材料;用少量的Co替代化合物中Si,Al元素可以将化合物的居里温度提高至室温;对La(Fe1-yCoy)xSi13-x化合物,适量的Si,Co组合可使化合物在室温产生可与Gd5Si2Ge2比拟的磁热效应;加入适量的间隙原子H,也可使La(FexSi1-x)13在室温的磁热性能远远大于金属Gd;对含Si量低及含Si量高的La(FexSi1-x)13化合物在相转变点附近由温度和磁场诱导相变的本质做了详细阐述。
