针对工业场景下经典迭代最近点(iterative closest point,ICP)算法在点云位姿估计中初始位姿敏感度高、迭代时间长的问题,提出一种基于RGB图像的快速点云配准方法。分别采集RGB图像和点云数据,使用ORB(oriented FAST and rotated BRIEF...针对工业场景下经典迭代最近点(iterative closest point,ICP)算法在点云位姿估计中初始位姿敏感度高、迭代时间长的问题,提出一种基于RGB图像的快速点云配准方法。分别采集RGB图像和点云数据,使用ORB(oriented FAST and rotated BRIEF)算法提取RGB图像特征点,利用Brute-Force算法进行初始匹配,采用随机采样一致性算法优化匹配,得到单应矩阵和旋转平移矩阵,求解汽车零配件初始位姿。进一步采用主成分分析法和双向KD树近邻搜索算法对预处理后的点云数据进行精确配准。实验结果表明,所提算法相较ICP算法,在配准速度和精度上分别提高了87.2%和5.0%,相对于FR-ICP(fast and robust iterative closest point)算法,在配准精度相当的情况下,配准速度提高了55%。展开更多
微塑料污染已成为全球性的重要环境问题。近年来,土壤微塑料的环境行为与生态效应受到了越来越多科研工作者的关注,相关论文的发表量呈现快速增长的趋势,且该领域研究面广、主题多样,研究内容多维深化,宏观-微观尺度变化复杂,缺乏对研...微塑料污染已成为全球性的重要环境问题。近年来,土壤微塑料的环境行为与生态效应受到了越来越多科研工作者的关注,相关论文的发表量呈现快速增长的趋势,且该领域研究面广、主题多样,研究内容多维深化,宏观-微观尺度变化复杂,缺乏对研究进展和态势系统的定量分析。因此,本研究基于Web of Science(WoS)核心数据库,对土壤微塑料环境行为与生态效应领域已发表的文章进行计量分析,总结了该领域的研究现状与热点,结果表明:1)该领域发文量自2018年起呈快速增长趋势;2)小粒径塑料的定量与表征方法是研究热点之一,由于先前的检测技术无法满足现阶段分析的需求,因此出现了多种新型检测技术,但仍存在一定局限性,阻碍了对微塑料生态效应的深入理解;3)微塑料可通过塑料地膜、轮胎磨损等多种途径进入土壤,迁移与老化是其在土壤环境中的重要行为,当前多数研究集中于微塑料在土壤中的迁移机理与影响因素上,而关于微塑料老化以及老化微塑料生态效应的研究相对匮乏;4)微塑料对生态环境的影响涵盖了多个方面,包括对土壤动物、重金属、植物、土壤微生物以及地球化学循环的影响。然而,目前的研究主要集中在短期室内实验上,缺乏长期的原位研究,这限制了对微塑料在自然环境中持续影响的理解;5)为缓解微塑料在土壤生态系统中的毒理效应,生物质炭和可生物降解塑料的使用被证明是有效措施。这些材料不仅能改善土壤结构,还能通过吸附和降解机制减轻微塑料的影响。展开更多
贵州合肥铜锣井大型锰矿床位于鄂渝湘黔前陆褶皱冲断带西部,合肥次级成矿亚带的深溪-八里锰矿矿带。矿区主要出露地层为寒武系第三统-芙蓉统、奥陶系下统娄山关组,奥陶系下统桐梓组、红花园组、中-下统湄潭组,二叠系阳新统梁山组、栖霞...贵州合肥铜锣井大型锰矿床位于鄂渝湘黔前陆褶皱冲断带西部,合肥次级成矿亚带的深溪-八里锰矿矿带。矿区主要出露地层为寒武系第三统-芙蓉统、奥陶系下统娄山关组,奥陶系下统桐梓组、红花园组、中-下统湄潭组,二叠系阳新统梁山组、栖霞组、茅口组,乐平统龙潭组、长兴组地层,三叠系下统夜郎组、中-下统嘉陵江组、中统关岭组地层,第四系。锰矿体产于二叠系阳新统茅口组第三段含锰岩系下部,呈层状、似层状产出,矿石结构主要为内碎屑结构,纹层状、斑杂状、块状构造,矿体厚度与含锰岩系厚度呈正相关,矿体厚度为0.3~3.5 m, Mn品位为12%~31%,平均为19.27%。展开更多
Plant anatomy is patterned early during leaf development which suggests studying the spatial–temporal transcriptomes of primordia will help identify critical regulative and functional genes.We successfully isolated t...Plant anatomy is patterned early during leaf development which suggests studying the spatial–temporal transcriptomes of primordia will help identify critical regulative and functional genes.We successfully isolated the leaf primordia tissues from the C3grass rice and the C4grass foxtail millet by laser capture microdissection(LCM)and studied the gene expression throughout leaf developmental stages.Our data analysis uncovered the conserved expression patterns of certain gene clusters both in rice and foxtail millet during leaf development.We revealed genes and transcription factors involved in vein formation,stomatal development,and suberin accumulation.We identified 79 candidate genes associated with functional regulation of C4anatomy formation.Screening phenotype of the candidate genes revealed that knock-out of a putative polar auxin transport related gene NAL1 resulted significantly reduced veinal space in rice leaf.Our present work provides a foundation for future analyses of genes with novel functions in grasses and their role in leaf development,in particular the role in leaves with a contrasting C3vs.C4biosynthetic pathway.展开更多
文摘针对工业场景下经典迭代最近点(iterative closest point,ICP)算法在点云位姿估计中初始位姿敏感度高、迭代时间长的问题,提出一种基于RGB图像的快速点云配准方法。分别采集RGB图像和点云数据,使用ORB(oriented FAST and rotated BRIEF)算法提取RGB图像特征点,利用Brute-Force算法进行初始匹配,采用随机采样一致性算法优化匹配,得到单应矩阵和旋转平移矩阵,求解汽车零配件初始位姿。进一步采用主成分分析法和双向KD树近邻搜索算法对预处理后的点云数据进行精确配准。实验结果表明,所提算法相较ICP算法,在配准速度和精度上分别提高了87.2%和5.0%,相对于FR-ICP(fast and robust iterative closest point)算法,在配准精度相当的情况下,配准速度提高了55%。
文摘微塑料污染已成为全球性的重要环境问题。近年来,土壤微塑料的环境行为与生态效应受到了越来越多科研工作者的关注,相关论文的发表量呈现快速增长的趋势,且该领域研究面广、主题多样,研究内容多维深化,宏观-微观尺度变化复杂,缺乏对研究进展和态势系统的定量分析。因此,本研究基于Web of Science(WoS)核心数据库,对土壤微塑料环境行为与生态效应领域已发表的文章进行计量分析,总结了该领域的研究现状与热点,结果表明:1)该领域发文量自2018年起呈快速增长趋势;2)小粒径塑料的定量与表征方法是研究热点之一,由于先前的检测技术无法满足现阶段分析的需求,因此出现了多种新型检测技术,但仍存在一定局限性,阻碍了对微塑料生态效应的深入理解;3)微塑料可通过塑料地膜、轮胎磨损等多种途径进入土壤,迁移与老化是其在土壤环境中的重要行为,当前多数研究集中于微塑料在土壤中的迁移机理与影响因素上,而关于微塑料老化以及老化微塑料生态效应的研究相对匮乏;4)微塑料对生态环境的影响涵盖了多个方面,包括对土壤动物、重金属、植物、土壤微生物以及地球化学循环的影响。然而,目前的研究主要集中在短期室内实验上,缺乏长期的原位研究,这限制了对微塑料在自然环境中持续影响的理解;5)为缓解微塑料在土壤生态系统中的毒理效应,生物质炭和可生物降解塑料的使用被证明是有效措施。这些材料不仅能改善土壤结构,还能通过吸附和降解机制减轻微塑料的影响。
文摘贵州合肥铜锣井大型锰矿床位于鄂渝湘黔前陆褶皱冲断带西部,合肥次级成矿亚带的深溪-八里锰矿矿带。矿区主要出露地层为寒武系第三统-芙蓉统、奥陶系下统娄山关组,奥陶系下统桐梓组、红花园组、中-下统湄潭组,二叠系阳新统梁山组、栖霞组、茅口组,乐平统龙潭组、长兴组地层,三叠系下统夜郎组、中-下统嘉陵江组、中统关岭组地层,第四系。锰矿体产于二叠系阳新统茅口组第三段含锰岩系下部,呈层状、似层状产出,矿石结构主要为内碎屑结构,纹层状、斑杂状、块状构造,矿体厚度与含锰岩系厚度呈正相关,矿体厚度为0.3~3.5 m, Mn品位为12%~31%,平均为19.27%。
基金supported by the National Key Research and Development Program of China(NKRDP)(2022YFF1001700)the Agricultural Science and Technology Innovation Program(2020YFE0202300)the National Natural Science Foundation of China(31871313)。
文摘Plant anatomy is patterned early during leaf development which suggests studying the spatial–temporal transcriptomes of primordia will help identify critical regulative and functional genes.We successfully isolated the leaf primordia tissues from the C3grass rice and the C4grass foxtail millet by laser capture microdissection(LCM)and studied the gene expression throughout leaf developmental stages.Our data analysis uncovered the conserved expression patterns of certain gene clusters both in rice and foxtail millet during leaf development.We revealed genes and transcription factors involved in vein formation,stomatal development,and suberin accumulation.We identified 79 candidate genes associated with functional regulation of C4anatomy formation.Screening phenotype of the candidate genes revealed that knock-out of a putative polar auxin transport related gene NAL1 resulted significantly reduced veinal space in rice leaf.Our present work provides a foundation for future analyses of genes with novel functions in grasses and their role in leaf development,in particular the role in leaves with a contrasting C3vs.C4biosynthetic pathway.
基金中国地质调查局项目(编号:121201103000150020)及其二级项目(编号:DD20160346)贵州省合肥锰矿整装勘查找矿预测及与技术运用示范项目(编号:121201004000160901-32)+4 种基金贵州省锰矿资源预测评价科技创新人才团队(黔科合平台人才[2018] 5618)贵州省地质矿产勘查开发局地质科研项目(黔地矿科合[2016] 3)联合资助the program of the China Geological Survey(No.121201103000150020)and its secondary project(No.DD20160346)Prospecting Prognosis and Technology Application Demonstration Projects for Full-scale Exploration of Zunyi Manganese Mine in Guizhou Province(No.121201004000160901-32Science and Technology Innovation Talent Team of Prediction and Evaluation of Manganese Ore Resources in Guizhou(Scientific research contract of platform and talent in Guizhou [2018] 5618)Geological science and technology project of Guizhou Bureau of Geology and Mineral Exploration and Development(Scientific research contract of geology and mining in Guizhou [2016]3)
