Based on dynastic period division and AMS ^14 C dating performed on the sedimentary layers at Zhongba and Yuxi sites,and also the analysis of Na,Ca and Mg of 201 sedimentary samples from Zhongba site and that of Ca an...Based on dynastic period division and AMS ^14 C dating performed on the sedimentary layers at Zhongba and Yuxi sites,and also the analysis of Na,Ca and Mg of 201 sedimentary samples from Zhongba site and that of Ca and Na in 47 sedimentary samples from Yuxi by using an inductively coupled plasma-mass spectrometry（ICP）,we found that there were 35 time periods when the contents of Ca and Na were reversely correlated,i.e.whenever the content of Ca was the highest,the content of Na was the lowest,and vice versa. Among them,there were 21 time periods when the content of Ca was the highest,and Na was the lowest,indicating that there were about 21 prosperous periods of ancient salt production at Zhongba site since 3000BC.Other 14 time periods with the peak values of Na while the low values of Ca indicate 14 declined periods of salt production at Zhongba site since 3000BC.The conclusion obtained from the reverse relationship between Ca and Na contents in this paper is consistent with that＂the salt production at Zhongba site started in the new stone age,developed in the Xia and Shang dynasties,reached at the heyday in periods from the Western Zhou to the Han Dynasties,maintained stable to develop in the Tang and the Song dynasties,and gradually declined after the Song Dynasty because the sea salt were conveyed into Sichuan region,however,still had production in the 1970s-1980s＂,educed from archeological exploration.All the above mentioned results indicate that there is a reverse relationship obviously between the contents of Na and Ca in sediments at Zhongba site for ancient salt production,which can be used to reveal the process of rise and decline of ancient salt industry at Zhongba site.展开更多
文章对合肥膨胀土做无荷载膨胀试验,分别选取原状土、浸水3h、浸水24h及浸水72h土样进行电镜扫描;基于ArcGIS软件对环境扫描电子显微镜(environmental scanning electron microscope,ESEM)图像进行三维信息的提取,分析不同浸水时间下原...文章对合肥膨胀土做无荷载膨胀试验,分别选取原状土、浸水3h、浸水24h及浸水72h土样进行电镜扫描;基于ArcGIS软件对环境扫描电子显微镜(environmental scanning electron microscope,ESEM)图像进行三维信息的提取,分析不同浸水时间下原状膨胀土的微结构、颗粒(团聚体)三维分形维数。结果表明:随着浸水时间增加,膨胀土的膨胀速率逐渐减小,并趋于0;而颗粒自相似性变差,即颗粒三维分形维数逐渐减小。展开更多
基于扫描电子显微镜(scanning electron microscope,SEM)图像对土体微观结构特征进行定量分析是一种科学、有效的方法。目前,土体微结构分析一般是对SEM图像进行二值化处理,但是阈值的选择对结果影响较大。文章基于ArcGIS软件在三维空...基于扫描电子显微镜(scanning electron microscope,SEM)图像对土体微观结构特征进行定量分析是一种科学、有效的方法。目前,土体微结构分析一般是对SEM图像进行二值化处理,但是阈值的选择对结果影响较大。文章基于ArcGIS软件在三维空间中分析不同浸水时间下膨胀土的环境扫描电子显微镜(environmental scanning electron microscope,ESEM)图像,定量分析不同浸水时间下土体的孔隙率,根据孔隙率反算不同浸水时间下灰度图像二值化的阈值。通过ArcGIS软件对灰度图像进行二值化,然后提取不同浸水时间下土体的孔隙、单元体,分析不同浸水时间下其微观结构的变化,研究表明:随着浸水时间的增加,孔隙的平均面积由29.57μm2逐渐增加到60.20μm2;单元体的平均面积由129.84μm2逐渐减小到39.93μm2;单元体、孔隙的形状系数在整个浸水周期内先增大再减小;单元体的排列熵由0.987 3逐渐增加到0.998 5,表明单元体的排列越来越无序,即单元体的定向性逐渐变差。展开更多
基金The Key Project of National Natural Science Foundation of China, No.90411015 University Doctoral Foundation of China, Grand No.20050284011+2 种基金 The Prior study project for Key Basic Scientific Issue of Nanjing University, Grand No. 0209005206 Open Foundation of the State Key Laboratory of Loess and Quaternary Geology from the Institute of Earth Environment, CAS, No.SKLLQG0503 Foundation of Modern Analyses Center of Nanjing University, No.0209001309.
文摘Based on dynastic period division and AMS ^14 C dating performed on the sedimentary layers at Zhongba and Yuxi sites,and also the analysis of Na,Ca and Mg of 201 sedimentary samples from Zhongba site and that of Ca and Na in 47 sedimentary samples from Yuxi by using an inductively coupled plasma-mass spectrometry（ICP）,we found that there were 35 time periods when the contents of Ca and Na were reversely correlated,i.e.whenever the content of Ca was the highest,the content of Na was the lowest,and vice versa. Among them,there were 21 time periods when the content of Ca was the highest,and Na was the lowest,indicating that there were about 21 prosperous periods of ancient salt production at Zhongba site since 3000BC.Other 14 time periods with the peak values of Na while the low values of Ca indicate 14 declined periods of salt production at Zhongba site since 3000BC.The conclusion obtained from the reverse relationship between Ca and Na contents in this paper is consistent with that＂the salt production at Zhongba site started in the new stone age,developed in the Xia and Shang dynasties,reached at the heyday in periods from the Western Zhou to the Han Dynasties,maintained stable to develop in the Tang and the Song dynasties,and gradually declined after the Song Dynasty because the sea salt were conveyed into Sichuan region,however,still had production in the 1970s-1980s＂,educed from archeological exploration.All the above mentioned results indicate that there is a reverse relationship obviously between the contents of Na and Ca in sediments at Zhongba site for ancient salt production,which can be used to reveal the process of rise and decline of ancient salt industry at Zhongba site.
文摘文章对合肥膨胀土做无荷载膨胀试验,分别选取原状土、浸水3h、浸水24h及浸水72h土样进行电镜扫描;基于ArcGIS软件对环境扫描电子显微镜(environmental scanning electron microscope,ESEM)图像进行三维信息的提取,分析不同浸水时间下原状膨胀土的微结构、颗粒(团聚体)三维分形维数。结果表明:随着浸水时间增加,膨胀土的膨胀速率逐渐减小,并趋于0;而颗粒自相似性变差,即颗粒三维分形维数逐渐减小。
文摘基于扫描电子显微镜(scanning electron microscope,SEM)图像对土体微观结构特征进行定量分析是一种科学、有效的方法。目前,土体微结构分析一般是对SEM图像进行二值化处理,但是阈值的选择对结果影响较大。文章基于ArcGIS软件在三维空间中分析不同浸水时间下膨胀土的环境扫描电子显微镜(environmental scanning electron microscope,ESEM)图像,定量分析不同浸水时间下土体的孔隙率,根据孔隙率反算不同浸水时间下灰度图像二值化的阈值。通过ArcGIS软件对灰度图像进行二值化,然后提取不同浸水时间下土体的孔隙、单元体,分析不同浸水时间下其微观结构的变化,研究表明:随着浸水时间的增加,孔隙的平均面积由29.57μm2逐渐增加到60.20μm2;单元体的平均面积由129.84μm2逐渐减小到39.93μm2;单元体、孔隙的形状系数在整个浸水周期内先增大再减小;单元体的排列熵由0.987 3逐渐增加到0.998 5,表明单元体的排列越来越无序,即单元体的定向性逐渐变差。
