[Objective] This study aimed to explore the relationship between contents of heavy metals with soil type, altitude distribution as well as physical and chemical properties. [Method] Based on determination of contents ...[Objective] This study aimed to explore the relationship between contents of heavy metals with soil type, altitude distribution as well as physical and chemical properties. [Method] Based on determination of contents of soil heavy metals and soil physical and chemical properties from agricultural land in Central Yunnan Province, the relationship between soil heavy metals with soil type, altitude distribu- tion and soil physical and chemical properties were analyzed. [Result] The average contents of all heavy metals in farmland of Central Yunnan didn＇t extend their limits of Grade II in the National Soil Environmental Quality Standard （GB15618-1995）. and the heavy metals content in red soil was higher than that in other types. Soil Cd content changes slightly with the altitude, while contents of other heavy metals were greatly affected by altitude. There were extremely significant positive correlation between heavy metals and clay particle content, that is, soil with heavier texture has more heavy metals. There was positive correlation between pH and each heavy metal content; there were positive correlation between Mn with Pb, Cd, Hg and Hg; exchangeable Ca and Mg contents in soil show negative correlations with most heavy metals. [Conclusion] This study has provided scientific bases for the heavy metal management in Central Yunnan area.展开更多
There exists widely incomplete knowledge all over the world, but incomplete knowledge still cannot be dealt with in the process of ontology construction. Hence, a method for fuzzy ontology construction based on incomp...There exists widely incomplete knowledge all over the world, but incomplete knowledge still cannot be dealt with in the process of ontology construction. Hence, a method for fuzzy ontology construction based on incomplete knowledge is proposed. First, the calculation principle of the attribute weight of the ontology concept is presented, and the calculation function of the attribute weight is derived through experiments. Then, the membership degree of the incomplete individual to the concept is computed. Finally, the incomplete individual is classified according to the principle of the variable precision rough set model. The experimental results show that the average precision of the classification of the incomplete individuals is 81.7% when the common attributes are omitted and that it is difficult to classify the incomplete individuals correctly when the private attributes are omitted. This method is significant for handling incomplete knowledge in the process of ontology construction.展开更多
文摘[Objective] This study aimed to explore the relationship between contents of heavy metals with soil type, altitude distribution as well as physical and chemical properties. [Method] Based on determination of contents of soil heavy metals and soil physical and chemical properties from agricultural land in Central Yunnan Province, the relationship between soil heavy metals with soil type, altitude distribu- tion and soil physical and chemical properties were analyzed. [Result] The average contents of all heavy metals in farmland of Central Yunnan didn＇t extend their limits of Grade II in the National Soil Environmental Quality Standard （GB15618-1995）. and the heavy metals content in red soil was higher than that in other types. Soil Cd content changes slightly with the altitude, while contents of other heavy metals were greatly affected by altitude. There were extremely significant positive correlation between heavy metals and clay particle content, that is, soil with heavier texture has more heavy metals. There was positive correlation between pH and each heavy metal content; there were positive correlation between Mn with Pb, Cd, Hg and Hg; exchangeable Ca and Mg contents in soil show negative correlations with most heavy metals. [Conclusion] This study has provided scientific bases for the heavy metal management in Central Yunnan area.
基金supported by the Beijing Natural Science Foundation under Grant No.4123094 the Science and Technology Project of Beijing Municipal Commission of Education under Grants No.KM201110028020,No. KM201010028019 Beijing Key Construction Discipline“Computer Application Technology”
文摘There exists widely incomplete knowledge all over the world, but incomplete knowledge still cannot be dealt with in the process of ontology construction. Hence, a method for fuzzy ontology construction based on incomplete knowledge is proposed. First, the calculation principle of the attribute weight of the ontology concept is presented, and the calculation function of the attribute weight is derived through experiments. Then, the membership degree of the incomplete individual to the concept is computed. Finally, the incomplete individual is classified according to the principle of the variable precision rough set model. The experimental results show that the average precision of the classification of the incomplete individuals is 81.7% when the common attributes are omitted and that it is difficult to classify the incomplete individuals correctly when the private attributes are omitted. This method is significant for handling incomplete knowledge in the process of ontology construction.
