利用遥感技术快速准确地提取耕地信息是耕地保护的关键环节。以山东省商河县为例,提出了一种基于多季相分形特征的Landsat 8 OLI影像耕地信息提取方法。首先采用毯子覆盖法计算多季相遥感影像每个像元的上分形信号和下分形信号,对比分...利用遥感技术快速准确地提取耕地信息是耕地保护的关键环节。以山东省商河县为例,提出了一种基于多季相分形特征的Landsat 8 OLI影像耕地信息提取方法。首先采用毯子覆盖法计算多季相遥感影像每个像元的上分形信号和下分形信号,对比分析耕地和其他土地利用类型的分形特征,选取上分形信号的第3尺度作为特征尺度,提取商河县耕地空间分布特征;其次采用同时期的土地利用矢量数据、Esri land cover数据和统计数据进行耕地信息提取精度评价;最后分别设置多季相分形提取与单季相分形提取、现有土地利用数据产品的对比实验,并基于点位匹配度和面积匹配度进行评价。结果表明:多季相数据更能反映农作物生长的复杂性,有助于提高耕地信息的提取精度;不同土地利用类型在不同分形尺度的信号值各不相同,分形特征可以在不同尺度上清晰地刻画出不同土地利用类型的分异性;基于矢量数据和Esri land cover数据评价的多季相分形特征耕地提取点位匹配度为87.13%和89.83%,面积匹配度为99.73%和97.91%,均比单季相分形提取结果精度高;综合考虑点位匹配度、面积匹配度和空间分布特征,研发方法能有效区分耕地和其他土地利用类型,提取结果更优,且与统计数据有更高的一致性。该方法可准确提取耕地信息,为耕地的动态监测和损害评估提供技术支撑。展开更多
It has been long believed there should be some relations between traffic system and urbanization,but the in-teraction between them,especially on the regional level,has been not in consideration due to the difficulty i...It has been long believed there should be some relations between traffic system and urbanization,but the in-teraction between them,especially on the regional level,has been not in consideration due to the difficulty in quantitative analysis.Based on the development of Jilin Province during 1981-2003,the paper analyzed the relation with the grey-relation model which was adjusted to fit specific problem,and came to some conclusions.Firstly,there exists ob-vious and strong correlation between traffic system and urbanization.Secondly,urbanization responds to the develop-ment of traffic system mainly on the level of urbanization,such as population and developed area,however,less on urbanization quality.Thirdly,traffic system influences urbanization as a whole except for several peculiar factors,which means we should optimize the whole traffic system to promote urbanization.Based on those conclusions,the paper illustrated the mechanism of traffic system,promoting urbanization scale and urbanization quality.展开更多
Nd（OH）3 particles sized of nanometer have been prepared using the different methods. The obtained neodymium hydroxide samples were investigated using the enhanced electronic Raman spectroscopy, Xray diffraction, tra...Nd（OH）3 particles sized of nanometer have been prepared using the different methods. The obtained neodymium hydroxide samples were investigated using the enhanced electronic Raman spectroscopy, Xray diffraction, transmission electron microscopy, as well as field emission electron microscopy. Observable changes in electronic Raman bands were found among the electronic Raman spectra of Nd （OH）3 particles which formed under different physical-chemical conditions. Compared to the difference of the X-ray diffraction paterns, it suggests that the change of size and morphology of Nd （OH）3 particles occurs with subtle variation on dae coordination environment around the neodymium ions,展开更多
Activated fibroblasts and M2-polarized macrophages may contribute to the progression of pulmonary fibrosis by forming a positive feedback loop.This study was aimed to investigate whether fibroblasts and macrophages fo...Activated fibroblasts and M2-polarized macrophages may contribute to the progression of pulmonary fibrosis by forming a positive feedback loop.This study was aimed to investigate whether fibroblasts and macrophages form this loop by secreting SDF-1 and TGF-β and the impacts of neotuberostemonine(NTS)and tuberostemonine(TS).Mice were intratracheally injected with 3 U·kg^(-1)bleomycin and orally administered with 30 mg·kg^(-1)NTS or TS.Primary pulmonary fibroblasts(PFBs)and MH-S cells(alveolar macrophages)were used in vitro.The animal experiments showed that NTS and TS improved fibrosis related indicators,inhibited fibroblast activation and macrophage M2 polarization,and reduced the levels of TGF-β and SDF-1 in alveolar lavage fluid.Cell experiments showed that TGF-β1 may activated fibroblasts into myofibroblasts secreting SDF-1 by activating the PI3K/AKT/HIF-1αand PI3K/PAK/RAF/ERK/HIF-1αpathways.It was also found for the first time that SDF-1 was able to directly polarize macrophages into M2 phenotype secreting TGF-β through the same pathways as mentioned above.Moreover,the results of the cell coculture confirmed that fibroblasts and macrophages actually developed a feedback loop to promote fibrosis,and the secretion of TGF-β and SDF-1 was crucial for maintaining this loop.NTS and TS may disturb this loop through inhibiting both the PI3K/AKT/HIF-1αand PI3K/PAK/RAF/ERK/HIF-1α pathways to improve pulmonary fibrosis.NTS and TS are stereoisomeric alkaloids with pyrrole[1,2-ajazapine skeleton,and their effect on improving pulmonary fibrosis may be largely attributed to their parent nucleus.Moreover,this study found that inhibition of both the AKT and ERK pathways is essential for maximizing the improvement of pulmonary fibrosis.展开更多
文摘利用遥感技术快速准确地提取耕地信息是耕地保护的关键环节。以山东省商河县为例,提出了一种基于多季相分形特征的Landsat 8 OLI影像耕地信息提取方法。首先采用毯子覆盖法计算多季相遥感影像每个像元的上分形信号和下分形信号,对比分析耕地和其他土地利用类型的分形特征,选取上分形信号的第3尺度作为特征尺度,提取商河县耕地空间分布特征;其次采用同时期的土地利用矢量数据、Esri land cover数据和统计数据进行耕地信息提取精度评价;最后分别设置多季相分形提取与单季相分形提取、现有土地利用数据产品的对比实验,并基于点位匹配度和面积匹配度进行评价。结果表明:多季相数据更能反映农作物生长的复杂性,有助于提高耕地信息的提取精度;不同土地利用类型在不同分形尺度的信号值各不相同,分形特征可以在不同尺度上清晰地刻画出不同土地利用类型的分异性;基于矢量数据和Esri land cover数据评价的多季相分形特征耕地提取点位匹配度为87.13%和89.83%,面积匹配度为99.73%和97.91%,均比单季相分形提取结果精度高;综合考虑点位匹配度、面积匹配度和空间分布特征,研发方法能有效区分耕地和其他土地利用类型,提取结果更优,且与统计数据有更高的一致性。该方法可准确提取耕地信息,为耕地的动态监测和损害评估提供技术支撑。
基金Under the auspices of the National Natural Science Foundation of China(No.40341008)
文摘It has been long believed there should be some relations between traffic system and urbanization,but the in-teraction between them,especially on the regional level,has been not in consideration due to the difficulty in quantitative analysis.Based on the development of Jilin Province during 1981-2003,the paper analyzed the relation with the grey-relation model which was adjusted to fit specific problem,and came to some conclusions.Firstly,there exists ob-vious and strong correlation between traffic system and urbanization.Secondly,urbanization responds to the develop-ment of traffic system mainly on the level of urbanization,such as population and developed area,however,less on urbanization quality.Thirdly,traffic system influences urbanization as a whole except for several peculiar factors,which means we should optimize the whole traffic system to promote urbanization.Based on those conclusions,the paper illustrated the mechanism of traffic system,promoting urbanization scale and urbanization quality.
文摘Nd（OH）3 particles sized of nanometer have been prepared using the different methods. The obtained neodymium hydroxide samples were investigated using the enhanced electronic Raman spectroscopy, Xray diffraction, transmission electron microscopy, as well as field emission electron microscopy. Observable changes in electronic Raman bands were found among the electronic Raman spectra of Nd （OH）3 particles which formed under different physical-chemical conditions. Compared to the difference of the X-ray diffraction paterns, it suggests that the change of size and morphology of Nd （OH）3 particles occurs with subtle variation on dae coordination environment around the neodymium ions,
基金supported by the National Natural Science Foundation of China(No.81873075).
文摘Activated fibroblasts and M2-polarized macrophages may contribute to the progression of pulmonary fibrosis by forming a positive feedback loop.This study was aimed to investigate whether fibroblasts and macrophages form this loop by secreting SDF-1 and TGF-β and the impacts of neotuberostemonine(NTS)and tuberostemonine(TS).Mice were intratracheally injected with 3 U·kg^(-1)bleomycin and orally administered with 30 mg·kg^(-1)NTS or TS.Primary pulmonary fibroblasts(PFBs)and MH-S cells(alveolar macrophages)were used in vitro.The animal experiments showed that NTS and TS improved fibrosis related indicators,inhibited fibroblast activation and macrophage M2 polarization,and reduced the levels of TGF-β and SDF-1 in alveolar lavage fluid.Cell experiments showed that TGF-β1 may activated fibroblasts into myofibroblasts secreting SDF-1 by activating the PI3K/AKT/HIF-1αand PI3K/PAK/RAF/ERK/HIF-1αpathways.It was also found for the first time that SDF-1 was able to directly polarize macrophages into M2 phenotype secreting TGF-β through the same pathways as mentioned above.Moreover,the results of the cell coculture confirmed that fibroblasts and macrophages actually developed a feedback loop to promote fibrosis,and the secretion of TGF-β and SDF-1 was crucial for maintaining this loop.NTS and TS may disturb this loop through inhibiting both the PI3K/AKT/HIF-1αand PI3K/PAK/RAF/ERK/HIF-1α pathways to improve pulmonary fibrosis.NTS and TS are stereoisomeric alkaloids with pyrrole[1,2-ajazapine skeleton,and their effect on improving pulmonary fibrosis may be largely attributed to their parent nucleus.Moreover,this study found that inhibition of both the AKT and ERK pathways is essential for maximizing the improvement of pulmonary fibrosis.
