地下水管漏水普遍,造成水资源和经济损失。有效的漏水探测技术缺乏,尤其因供水管道埋设在地下,难以及时发现漏水。长波极化SAR信号穿透能力强,可记录次地表含水量信息,为漏水探测提供了新机遇。本研究利用SAOCOM数据,通过Singh七分量极...地下水管漏水普遍,造成水资源和经济损失。有效的漏水探测技术缺乏,尤其因供水管道埋设在地下,难以及时发现漏水。长波极化SAR信号穿透能力强,可记录次地表含水量信息,为漏水探测提供了新机遇。本研究利用SAOCOM数据,通过Singh七分量极化分解方法提取城区地表散射能量,结合地面实测数据,训练了随机森林、多层感知机和XGBoost三种机器学习模型预测漏点。最后构建集成模型,通过投票机制提高漏点检测准确性,准确率达81.20%。通过DBSCAN(density-based spatial clustering of applications with noise)密度聚类方法优化预测结果,将潜在漏点减少至1 265个,发现所有真实漏点均位于疑似漏点的150 m缓冲区内。本研究展示了利用PolSAR数据结合机器学习技术在城市水管漏损检测中的潜力,并为未来相关研究提供了有价值的方法和经验。展开更多
该研究以不同年份(0~10年)浓酱兼香型白酒为研究对象,通过单因素试验对液液萃取(LLE)前处理条件进行优化后,通过气相色谱-质谱联用(GC-MS)技术对其挥发性风味成分进行检测,并结合香气活力值(OAV),利用主成分分析(PCA)分析不同年份浓酱...该研究以不同年份(0~10年)浓酱兼香型白酒为研究对象,通过单因素试验对液液萃取(LLE)前处理条件进行优化后,通过气相色谱-质谱联用(GC-MS)技术对其挥发性风味成分进行检测,并结合香气活力值(OAV),利用主成分分析(PCA)分析不同年份浓酱兼香型白酒挥发性风味物质的变化规律。结果表明,最佳LLE条件为添加75 g NaCl,采用二氯甲烷萃取3次,每次萃取5 min。从不同年份浓酱兼香型白酒中共鉴定出65种挥发性风味物质,包括醇类12种、醛类6种、酸类9种、酮类3种、酯类31种、其他类4种。PCA可有效区分不同年份酒样挥发性风味的差异,己酸乙酯、辛酸乙酯、丁酸乙酯、苯乙酸乙酯、3-苯丙酸乙酯等14种挥发性风味成分为0~1年酒样主要风味影响组分,十六酸乙酯、丁酸、己酸为2~4年酒样的主要风味影响组分,丁酸为5年和7年酒样的主要风味影响组分,己酸为6年和9~10年酒样的主要风味影响组分,异丁酸乙酯为8年酒样的主要风味影响组分。展开更多
The comprehensive carrying capacity of urban land can reflect the re- source level, economic scale, social development and environmental pressure of ur- ban land carrying. The assessment indicator system of urban land...The comprehensive carrying capacity of urban land can reflect the re- source level, economic scale, social development and environmental pressure of ur- ban land carrying. The assessment indicator system of urban land comprehensive carrying capacity was constructed from the 4 aspects of resource, economy, society, environment, and principal component analysis and cluster analysis were used to evaluate the urban land comprehensive carrying capacity of Guangxi and the 14 cities in 2005-2014, and analyzed its spatial and temporal characteristics as well as the driving forces, with the aim to provide references for improving the urban land comprehensive carrying capacity. The results showed that, the overall urban land comprehensive carrying capacity in Guangxi increased in 2005-2014, and there were significant differences in the land comprehensive carrying capacities among the cities in Guangxi in 2005-2014, in which Liuzhou, Guilin, Nanning belonged to the regions with the highest carrying capacity, while Beihai, Yulin, Wutong belonged to the regions with high carrying capacity, and the carrying capacities of the other cities changed with the changes of time. The economic development degree was an important factor influencing urban land comprehensive carrying capacity, but could not directly represent the urban land comprehensive carrying capacity level.展开更多
文摘地下水管漏水普遍,造成水资源和经济损失。有效的漏水探测技术缺乏,尤其因供水管道埋设在地下,难以及时发现漏水。长波极化SAR信号穿透能力强,可记录次地表含水量信息,为漏水探测提供了新机遇。本研究利用SAOCOM数据,通过Singh七分量极化分解方法提取城区地表散射能量,结合地面实测数据,训练了随机森林、多层感知机和XGBoost三种机器学习模型预测漏点。最后构建集成模型,通过投票机制提高漏点检测准确性,准确率达81.20%。通过DBSCAN(density-based spatial clustering of applications with noise)密度聚类方法优化预测结果,将潜在漏点减少至1 265个,发现所有真实漏点均位于疑似漏点的150 m缓冲区内。本研究展示了利用PolSAR数据结合机器学习技术在城市水管漏损检测中的潜力,并为未来相关研究提供了有价值的方法和经验。
文摘该研究以不同年份(0~10年)浓酱兼香型白酒为研究对象,通过单因素试验对液液萃取(LLE)前处理条件进行优化后,通过气相色谱-质谱联用(GC-MS)技术对其挥发性风味成分进行检测,并结合香气活力值(OAV),利用主成分分析(PCA)分析不同年份浓酱兼香型白酒挥发性风味物质的变化规律。结果表明,最佳LLE条件为添加75 g NaCl,采用二氯甲烷萃取3次,每次萃取5 min。从不同年份浓酱兼香型白酒中共鉴定出65种挥发性风味物质,包括醇类12种、醛类6种、酸类9种、酮类3种、酯类31种、其他类4种。PCA可有效区分不同年份酒样挥发性风味的差异,己酸乙酯、辛酸乙酯、丁酸乙酯、苯乙酸乙酯、3-苯丙酸乙酯等14种挥发性风味成分为0~1年酒样主要风味影响组分,十六酸乙酯、丁酸、己酸为2~4年酒样的主要风味影响组分,丁酸为5年和7年酒样的主要风味影响组分,己酸为6年和9~10年酒样的主要风味影响组分,异丁酸乙酯为8年酒样的主要风味影响组分。
基金Supported by the Open Bidding Projects of the Office of Land and Resources of the Guangxi Zhuang Autonomous Region(GXZC2015-G3-0575-GTZB)~~
文摘The comprehensive carrying capacity of urban land can reflect the re- source level, economic scale, social development and environmental pressure of ur- ban land carrying. The assessment indicator system of urban land comprehensive carrying capacity was constructed from the 4 aspects of resource, economy, society, environment, and principal component analysis and cluster analysis were used to evaluate the urban land comprehensive carrying capacity of Guangxi and the 14 cities in 2005-2014, and analyzed its spatial and temporal characteristics as well as the driving forces, with the aim to provide references for improving the urban land comprehensive carrying capacity. The results showed that, the overall urban land comprehensive carrying capacity in Guangxi increased in 2005-2014, and there were significant differences in the land comprehensive carrying capacities among the cities in Guangxi in 2005-2014, in which Liuzhou, Guilin, Nanning belonged to the regions with the highest carrying capacity, while Beihai, Yulin, Wutong belonged to the regions with high carrying capacity, and the carrying capacities of the other cities changed with the changes of time. The economic development degree was an important factor influencing urban land comprehensive carrying capacity, but could not directly represent the urban land comprehensive carrying capacity level.
