Electroformed diamond tools have been used for many years in grinding and cutting fields while electrodeposited diamond composite coatings have been widely studied due to their desirable hardness,wear and corrosion re...Electroformed diamond tools have been used for many years in grinding and cutting fields while electrodeposited diamond composite coatings have been widely studied due to their desirable hardness,wear and corrosion resistance.This article reports the detrimental impact of diamond magnetism on the composites microstructure and gives explanations.Microstructure differences between composites that,respectively,contained no-further-treated diamond,magnetism-strengthening treated diamond and magnetism weakening treated diamond were carefully observed.It is shown that diamond magnetization treatment drastically harms the composite microstructure(e.g.,roughening the coating surface,coarsening the matrix grain,and more seriously,reducing the mechanical retention of diamond grains in the matrix) while demagnetization treatment does the opposite.All the observed facts could be explained by the electromagnetic interaction between magnetic fields produced by magnetic diamond grains and electric current(moving cations) during the electrodeposition process.展开更多
In the past two years,many progresses were made in magnetospheric physics by the data of OMNI,SuperMAG networks,Double Star Program,Cluster,THEMIS,RBSP,DMSP,DEMETER,NOAA,Van Allen Probes,GOES,Geotail,Swarm,MMS,BeiDa,F...In the past two years,many progresses were made in magnetospheric physics by the data of OMNI,SuperMAG networks,Double Star Program,Cluster,THEMIS,RBSP,DMSP,DEMETER,NOAA,Van Allen Probes,GOES,Geotail,Swarm,MMS,BeiDa,Fengyun,ARTEMIS,MESSENGER,Juno,Chinese Mars ROVER,MAVEN,Tianwen-1,Venus Express,Lunar Prospector e.g.,or by computer simulations.This paper briefly reviews these works based on 356 papers published from January 2020 to December 2021.The subjects covered various sub-branches of Magnetospheric Physics,including solar wind-magnetosphere-ionosphere interaction,inner magnetosphere,outer magnetosphere,magnetic reconnection,planetary magnetosphere.展开更多
In this review,we discuss the structure and dynamics of the magnetospheric LowLatitude Boundary Layer(LLBL)based on recent results from multi-satellite missions Cluster and Double Star.This boundary layer,adjacent to ...In this review,we discuss the structure and dynamics of the magnetospheric LowLatitude Boundary Layer(LLBL)based on recent results from multi-satellite missions Cluster and Double Star.This boundary layer,adjacent to the magnetopause on the magnetospheric side,usually consists of a mixture of plasma of magnetospheric and magnetosheath origins,and plays an important role in the transfer of mass and energy from the solar wind into the magnetosphere and subsequent magnetospheric dynamics.During southward Interplanetary Magnetic Field(IMF)conditions,this boundary layer is generally considered to be formed as a result of the reconnection process between the IMF and magnetospheric magnetic field lines at the dayside magnetopause,and the structure and plasma properties inside the LLBL can be understood in terms of the time history since the reconnection process.During northward IMF conditions,the LLBL is usually thicker,and has more complex structure and topology.Recent observations confirm that the LLBL observed at the dayside can be formed by single lobe reconnection,dual lobe reconnection,or by sequential dual lobe reconnection,as well as partially by localized cross-field diffusion.The LLBL magnetic topology and plasma signatures inside the different sub-layers formed by these processes are discussed in this review.The role of the Kelvin-Helmholtz instability in the formation of the LLBL at the flank magnetopause is also discussed.Overall,we conclude that the LLBL observed at the flanks can be formed by the combination of processes,(dual)lobe reconnection and plasma mixing due to non-linear Kelvin-Helmholtz waves.展开更多
目的通过研究和搭建人工智能深度学习网络,实现多模态心脏磁共振(cardiac magnetic resonance,CMR)图像分割,并提升Dice系数。材料与方法回顾性分析来自2019年多序列CMR分割挑战赛的公开数据集,它包含了45例患者平衡稳态自由进动(balanc...目的通过研究和搭建人工智能深度学习网络,实现多模态心脏磁共振(cardiac magnetic resonance,CMR)图像分割,并提升Dice系数。材料与方法回顾性分析来自2019年多序列CMR分割挑战赛的公开数据集,它包含了45例患者平衡稳态自由进动(balanced-steady state free precession,bSSFP)模态,晚期钆增强(late gadolinium enhancement,LGE)模态与T2WI模态的CMR图像数据。本文构建了一种新的双流U型网络框架,实现bSSFP与LGE两种模态以及bSSFP与T2WI两种模态的CMR图像分割。在编码阶段,未配准各模态图像被交替地送入各自分支进行特征学习,所获取的特征图接着都流入共享层,实现多模态信息的交互补充,最终共享特征分开流出到各自分支进行解码输出。通过在45例患者的CMR图像数据集上进行五折交叉验证实验,分别对bSSFP与LGE模态、bSSFP与T2WI模态进行了分割,以Dice系数对提出的模型进行性能评估,Wilcoxon符号秩检验被用来检验模型差异性。结果在bSSFP与LGE模态的分割实验中,本文方法在bSSFP模态的平均Dice系数相较于传统UNet模型和最新的Swin-Unet模型都有显著提升(P<0.001);在LGE模态的平均Dice系数较传统UNet模型(P<0.001)、Swin-Unet模型(P=0.001)、双流UNet(P=0.021)均有显著提升。在bSSFP与T2WI模态的分割实验中,本文方法在bSSFP模态的平均Dice系数较UNet模型、Swin-Unet模型与双流UNet均有显著提升(P<0.001);在T2WI模态的平均Dice系数较UNet模型有显著提升(P<0.001),较Swin-Unet模型有提升(P=0.025)。结论本研究提出的双流U型网络框架为CMR图像多模态分割提供有效方法,且该网络提高了CMR图像bSSFP模态与LGE模态及bSSFP模态与T2WI模态的Dice系数,很好地解决了多模态CMR图像个体解剖学差异大和图像间存在灰度不一致问题,提升了模型的泛化能力。展开更多
基金This work was supported by Henan Agricultural University,the Natural Science Foundation of Henan Province(0411051300)the Project for Excel-lent University Teachers under the supervision of Henan Provincial Bureau of Education.
文摘Electroformed diamond tools have been used for many years in grinding and cutting fields while electrodeposited diamond composite coatings have been widely studied due to their desirable hardness,wear and corrosion resistance.This article reports the detrimental impact of diamond magnetism on the composites microstructure and gives explanations.Microstructure differences between composites that,respectively,contained no-further-treated diamond,magnetism-strengthening treated diamond and magnetism weakening treated diamond were carefully observed.It is shown that diamond magnetization treatment drastically harms the composite microstructure(e.g.,roughening the coating surface,coarsening the matrix grain,and more seriously,reducing the mechanical retention of diamond grains in the matrix) while demagnetization treatment does the opposite.All the observed facts could be explained by the electromagnetic interaction between magnetic fields produced by magnetic diamond grains and electric current(moving cations) during the electrodeposition process.
文摘In the past two years,many progresses were made in magnetospheric physics by the data of OMNI,SuperMAG networks,Double Star Program,Cluster,THEMIS,RBSP,DMSP,DEMETER,NOAA,Van Allen Probes,GOES,Geotail,Swarm,MMS,BeiDa,Fengyun,ARTEMIS,MESSENGER,Juno,Chinese Mars ROVER,MAVEN,Tianwen-1,Venus Express,Lunar Prospector e.g.,or by computer simulations.This paper briefly reviews these works based on 356 papers published from January 2020 to December 2021.The subjects covered various sub-branches of Magnetospheric Physics,including solar wind-magnetosphere-ionosphere interaction,inner magnetosphere,outer magnetosphere,magnetic reconnection,planetary magnetosphere.
文摘In this review,we discuss the structure and dynamics of the magnetospheric LowLatitude Boundary Layer(LLBL)based on recent results from multi-satellite missions Cluster and Double Star.This boundary layer,adjacent to the magnetopause on the magnetospheric side,usually consists of a mixture of plasma of magnetospheric and magnetosheath origins,and plays an important role in the transfer of mass and energy from the solar wind into the magnetosphere and subsequent magnetospheric dynamics.During southward Interplanetary Magnetic Field(IMF)conditions,this boundary layer is generally considered to be formed as a result of the reconnection process between the IMF and magnetospheric magnetic field lines at the dayside magnetopause,and the structure and plasma properties inside the LLBL can be understood in terms of the time history since the reconnection process.During northward IMF conditions,the LLBL is usually thicker,and has more complex structure and topology.Recent observations confirm that the LLBL observed at the dayside can be formed by single lobe reconnection,dual lobe reconnection,or by sequential dual lobe reconnection,as well as partially by localized cross-field diffusion.The LLBL magnetic topology and plasma signatures inside the different sub-layers formed by these processes are discussed in this review.The role of the Kelvin-Helmholtz instability in the formation of the LLBL at the flank magnetopause is also discussed.Overall,we conclude that the LLBL observed at the flanks can be formed by the combination of processes,(dual)lobe reconnection and plasma mixing due to non-linear Kelvin-Helmholtz waves.
文摘目的通过研究和搭建人工智能深度学习网络,实现多模态心脏磁共振(cardiac magnetic resonance,CMR)图像分割,并提升Dice系数。材料与方法回顾性分析来自2019年多序列CMR分割挑战赛的公开数据集,它包含了45例患者平衡稳态自由进动(balanced-steady state free precession,bSSFP)模态,晚期钆增强(late gadolinium enhancement,LGE)模态与T2WI模态的CMR图像数据。本文构建了一种新的双流U型网络框架,实现bSSFP与LGE两种模态以及bSSFP与T2WI两种模态的CMR图像分割。在编码阶段,未配准各模态图像被交替地送入各自分支进行特征学习,所获取的特征图接着都流入共享层,实现多模态信息的交互补充,最终共享特征分开流出到各自分支进行解码输出。通过在45例患者的CMR图像数据集上进行五折交叉验证实验,分别对bSSFP与LGE模态、bSSFP与T2WI模态进行了分割,以Dice系数对提出的模型进行性能评估,Wilcoxon符号秩检验被用来检验模型差异性。结果在bSSFP与LGE模态的分割实验中,本文方法在bSSFP模态的平均Dice系数相较于传统UNet模型和最新的Swin-Unet模型都有显著提升(P<0.001);在LGE模态的平均Dice系数较传统UNet模型(P<0.001)、Swin-Unet模型(P=0.001)、双流UNet(P=0.021)均有显著提升。在bSSFP与T2WI模态的分割实验中,本文方法在bSSFP模态的平均Dice系数较UNet模型、Swin-Unet模型与双流UNet均有显著提升(P<0.001);在T2WI模态的平均Dice系数较UNet模型有显著提升(P<0.001),较Swin-Unet模型有提升(P=0.025)。结论本研究提出的双流U型网络框架为CMR图像多模态分割提供有效方法,且该网络提高了CMR图像bSSFP模态与LGE模态及bSSFP模态与T2WI模态的Dice系数,很好地解决了多模态CMR图像个体解剖学差异大和图像间存在灰度不一致问题,提升了模型的泛化能力。
