The time evolution of the magnetic field aligned super-small-scale irregularities in the concentration of charged particles, existing in the near-Earth rarefied plasma, is studied with the help of the model simulation...The time evolution of the magnetic field aligned super-small-scale irregularities in the concentration of charged particles, existing in the near-Earth rarefied plasma, is studied with the help of the model simulation. A new version of the two-dimensional mathematical model, developed earlier in the Polar Geophysical Institute, is utilized to investigate the temporal history of the irregularity with circular cross section, created initially in the near-Earth plasma. The utilized model is based on a numerical solution of the Vlasov-Poisson system of equations, with the Vlasov equations describing the distribution functions of charged particles and the Poisson equation governing the self-consistent electric field. The results of simulation indicate that the mobility of the positive ions ought to influence essentially on the time evolution of the super-small-scale irregularities in the concentration of charged particles, existing in the near-Earth rarefied plasma.展开更多
Based on meteorological data including daily sunshine duration, temperature and precipitation from 97 meteorological stations in Hunan province during the period of 1981—2010, in combination with the field experiment...Based on meteorological data including daily sunshine duration, temperature and precipitation from 97 meteorological stations in Hunan province during the period of 1981—2010, in combination with the field experiment in different places at different sowing dates, the precise climatic risk zoning of double cropping super rice cultivation has been studied by using the spatial interpolation method and other Geographical Information System(GIS)technologies. Three key climatic factors were selected including chilling in May, high temperature heat damage during July to early August and low temperature damage in autumn in this study. Furthermore, based on the analysis of climatic conditions suitable for double cropping super rice cultivation and climatic disasters, 8-22 ℃ active accumulated temperature, sunshine duration from late March to October, climatic risk index of the low temperature in autumn, and climatic risk index of chilling in May were selected as key climatic factors to study the precise agro-meteorological regionalization of double cropping super rice in Hunan province. The results showed that: the high-yielding zones of double cropping super rice in Hunan were mainly located in Zhuzhou, Hengyang, Yongzhou and Chenzhou City, the moderate-yielding zones were primarily located in the east and north reaches of Dongting Lake,together with most of Changsha, Zhuzhou and Xiangtan City, and other regions in Hunan were not suitable for double cropping super rice. These findings can provide valuable information for the large-scale cultivation of double cropping super rice in Hunan province.展开更多
针对生成对抗网络(GAN)需要大量训练数据及点云数据稀缺且获取难度大的问题,提出一种基于少量数据集的三维点云生成模型。该模型首先通过重采样和水平旋转的方法实现数据增强,使第一级网络能够生成具有多样性的低分辨率点云;其次通过确...针对生成对抗网络(GAN)需要大量训练数据及点云数据稀缺且获取难度大的问题,提出一种基于少量数据集的三维点云生成模型。该模型首先通过重采样和水平旋转的方法实现数据增强,使第一级网络能够生成具有多样性的低分辨率点云;其次通过确保低分辨率点云与高分辨率点云之间的对应关系,实现点云的超分辨率生成;最后实现生成具有多样性的高分辨率点云。实验结果表明,在ShapeNet Part(ShapeNet Part Segmentation Dataset)数据集上,该模型的JS散度相较于Tree-GAN的JS散度下降了0.416,证明其性能优于Tree-GAN。展开更多
文摘The time evolution of the magnetic field aligned super-small-scale irregularities in the concentration of charged particles, existing in the near-Earth rarefied plasma, is studied with the help of the model simulation. A new version of the two-dimensional mathematical model, developed earlier in the Polar Geophysical Institute, is utilized to investigate the temporal history of the irregularity with circular cross section, created initially in the near-Earth plasma. The utilized model is based on a numerical solution of the Vlasov-Poisson system of equations, with the Vlasov equations describing the distribution functions of charged particles and the Poisson equation governing the self-consistent electric field. The results of simulation indicate that the mobility of the positive ions ought to influence essentially on the time evolution of the super-small-scale irregularities in the concentration of charged particles, existing in the near-Earth rarefied plasma.
基金China Special Fund for Meteorological Research in the Public Interest(201206045)
文摘Based on meteorological data including daily sunshine duration, temperature and precipitation from 97 meteorological stations in Hunan province during the period of 1981—2010, in combination with the field experiment in different places at different sowing dates, the precise climatic risk zoning of double cropping super rice cultivation has been studied by using the spatial interpolation method and other Geographical Information System(GIS)technologies. Three key climatic factors were selected including chilling in May, high temperature heat damage during July to early August and low temperature damage in autumn in this study. Furthermore, based on the analysis of climatic conditions suitable for double cropping super rice cultivation and climatic disasters, 8-22 ℃ active accumulated temperature, sunshine duration from late March to October, climatic risk index of the low temperature in autumn, and climatic risk index of chilling in May were selected as key climatic factors to study the precise agro-meteorological regionalization of double cropping super rice in Hunan province. The results showed that: the high-yielding zones of double cropping super rice in Hunan were mainly located in Zhuzhou, Hengyang, Yongzhou and Chenzhou City, the moderate-yielding zones were primarily located in the east and north reaches of Dongting Lake,together with most of Changsha, Zhuzhou and Xiangtan City, and other regions in Hunan were not suitable for double cropping super rice. These findings can provide valuable information for the large-scale cultivation of double cropping super rice in Hunan province.
文摘针对生成对抗网络(GAN)需要大量训练数据及点云数据稀缺且获取难度大的问题,提出一种基于少量数据集的三维点云生成模型。该模型首先通过重采样和水平旋转的方法实现数据增强,使第一级网络能够生成具有多样性的低分辨率点云;其次通过确保低分辨率点云与高分辨率点云之间的对应关系,实现点云的超分辨率生成;最后实现生成具有多样性的高分辨率点云。实验结果表明,在ShapeNet Part(ShapeNet Part Segmentation Dataset)数据集上,该模型的JS散度相较于Tree-GAN的JS散度下降了0.416,证明其性能优于Tree-GAN。
