为了揭示沙颍河流域生态系统服务价值(ESV),以沙颍河及其支流所流经的各地级市为研究区,利用PLUS(Patch-generating Land Use Simulation Model,PLUS)模型模拟不同情景下土地利用,采用当量因子法进行ESV评估.结果表明:2019年研究区用地...为了揭示沙颍河流域生态系统服务价值(ESV),以沙颍河及其支流所流经的各地级市为研究区,利用PLUS(Patch-generating Land Use Simulation Model,PLUS)模型模拟不同情景下土地利用,采用当量因子法进行ESV评估.结果表明:2019年研究区用地类型以耕地为主,而建设用地面积明显增长;仅耕地保护情景下2029年ESV有所提高,表明耕地对ESV的主导作用;耕地和林地的生态价值变化度大于1,表明其对该流域ESV变化影响大.该研究为沙颍河流域生态保护和国土空间规划提供科学依据.展开更多
Based on the results obtained from projection pursuit, all cycloalkanes investigated show an interesting classification. Thus, a new variable named class distance variable of cycloalkane, which essentially describes i...Based on the results obtained from projection pursuit, all cycloalkanes investigated show an interesting classification. Thus, a new variable named class distance variable of cycloalkane, which essentially describes information of branch, number of rings in the molecules and homologous series for cycloalkanes, is proposed. With the help of the new variable, both of fitting and prediction accuracy of the regression model can be dramatically improved.展开更多
文摘为了揭示沙颍河流域生态系统服务价值(ESV),以沙颍河及其支流所流经的各地级市为研究区,利用PLUS(Patch-generating Land Use Simulation Model,PLUS)模型模拟不同情景下土地利用,采用当量因子法进行ESV评估.结果表明:2019年研究区用地类型以耕地为主,而建设用地面积明显增长;仅耕地保护情景下2029年ESV有所提高,表明耕地对ESV的主导作用;耕地和林地的生态价值变化度大于1,表明其对该流域ESV变化影响大.该研究为沙颍河流域生态保护和国土空间规划提供科学依据.
文摘Based on the results obtained from projection pursuit, all cycloalkanes investigated show an interesting classification. Thus, a new variable named class distance variable of cycloalkane, which essentially describes information of branch, number of rings in the molecules and homologous series for cycloalkanes, is proposed. With the help of the new variable, both of fitting and prediction accuracy of the regression model can be dramatically improved.
