为了应对全球70%的未注册土地权的挑战,对地籍测绘方法的需求不断增长。由于传统的现场实地测量既耗时又耗费人力,因此土地管理部门一直提倡基于遥感的地籍测绘,但基于遥感影像的自动划界的准确性仍然是一项重大挑战。在这项研究中,使...为了应对全球70%的未注册土地权的挑战,对地籍测绘方法的需求不断增长。由于传统的现场实地测量既耗时又耗费人力,因此土地管理部门一直提倡基于遥感的地籍测绘,但基于遥感影像的自动划界的准确性仍然是一项重大挑战。在这项研究中,使用无人机获得的图像来探索深度全卷积网络(Fully Convolu-tional Networks,FCN)在城市和城郊地区进行地籍边界提取的能力。在甘肃天水的两个地点使用其他最先进的技术来测试FCN、多分辨率分割(Multi-Resolution Segmentation,MRS)和全局化边界概率(Globalized Probability of Boundary,gPb)算法的性能。实验结果表明:FCN在两个研究领域的表现均优于MRS和gPb,精度平均为0.79,召回率为0.37,F评分为0.50。总之,FCN能够有效地提取地籍边界,尤其是在大量地籍边界可见的情况下。这种自动化方法可以最大限度地减少手动数字化并减少实地工作,从而促进当前的地籍测绘和更新做法。展开更多
The effects of pre-stretching following solution treatment on the hardness and microstructures of aged 2524 aluminium alloy at 170 ℃ were studied.Ageing hardness values under different pre-stretching conditions were ...The effects of pre-stretching following solution treatment on the hardness and microstructures of aged 2524 aluminium alloy at 170 ℃ were studied.Ageing hardness values under different pre-stretching conditions were measured,and the corresponding microstructures were characterized by transmission electron microscopy（TEM）.The results show that compared with unstretched samples,the peak hardness is increased and the time to reach the peak hardness is reduced with the increase of pre-strain;the number density of S（Al2CuMg） phases is increased and the length is shortened in pre-stretched alloy.Additionally,the number density of GPB zones is decreased with the increase of pre-strain in peak-aged samples.When the pre-strain is up to 5%,S phases play the predominant contribution to the peak hardness.Fine and uniformly distributed S phases lead to a higher hardness than GPB zones together with S phases existing in conventionally aged 2524 alloy.展开更多
Microstructures of creep-aged 2524 （A1-4.3Cu-1.5Mg） aged at 170 ℃ with various stresses （0, 173 and 250 MPa） were studied on a creep machine. Ageing hardness curves under various stresses were plotted and the cor...Microstructures of creep-aged 2524 （A1-4.3Cu-1.5Mg） aged at 170 ℃ with various stresses （0, 173 and 250 MPa） were studied on a creep machine. Ageing hardness curves under various stresses were plotted and the corresponding microstructures were characterized by transmission electron microscopy （TEM）. The results show that the value of peak hardness is increased, while the time to reach the peak hardness is reduced under an external stress. Meanwhile, the length of S（Al2CuMg） phase is shorter and the number density of S phases is larger in the creep-aged alloy. The predominant contribution to the peak hardness can be ascribed to the GPB zones with an elastic stress.展开更多
文摘为了应对全球70%的未注册土地权的挑战,对地籍测绘方法的需求不断增长。由于传统的现场实地测量既耗时又耗费人力,因此土地管理部门一直提倡基于遥感的地籍测绘,但基于遥感影像的自动划界的准确性仍然是一项重大挑战。在这项研究中,使用无人机获得的图像来探索深度全卷积网络(Fully Convolu-tional Networks,FCN)在城市和城郊地区进行地籍边界提取的能力。在甘肃天水的两个地点使用其他最先进的技术来测试FCN、多分辨率分割(Multi-Resolution Segmentation,MRS)和全局化边界概率(Globalized Probability of Boundary,gPb)算法的性能。实验结果表明:FCN在两个研究领域的表现均优于MRS和gPb,精度平均为0.79,召回率为0.37,F评分为0.50。总之,FCN能够有效地提取地籍边界,尤其是在大量地籍边界可见的情况下。这种自动化方法可以最大限度地减少手动数字化并减少实地工作,从而促进当前的地籍测绘和更新做法。
基金Project(51001022) supported by the National Natural Science Foundation of ChinaProject supported by Innovative Research Team in University of Liaoning Province,China
文摘The effects of pre-stretching following solution treatment on the hardness and microstructures of aged 2524 aluminium alloy at 170 ℃ were studied.Ageing hardness values under different pre-stretching conditions were measured,and the corresponding microstructures were characterized by transmission electron microscopy（TEM）.The results show that compared with unstretched samples,the peak hardness is increased and the time to reach the peak hardness is reduced with the increase of pre-strain;the number density of S（Al2CuMg） phases is increased and the length is shortened in pre-stretched alloy.Additionally,the number density of GPB zones is decreased with the increase of pre-strain in peak-aged samples.When the pre-strain is up to 5%,S phases play the predominant contribution to the peak hardness.Fine and uniformly distributed S phases lead to a higher hardness than GPB zones together with S phases existing in conventionally aged 2524 alloy.
基金Project (2009BAG12A07-B02) supported by the National Science & Technology Pillar Program during the 11th Five-Year Plan Period,ChinaProject supported by Innovative Research Team in University of Liaoning Province,ChinaProject (51001022) supported by the National Natural Science Foundation of China
文摘Microstructures of creep-aged 2524 （A1-4.3Cu-1.5Mg） aged at 170 ℃ with various stresses （0, 173 and 250 MPa） were studied on a creep machine. Ageing hardness curves under various stresses were plotted and the corresponding microstructures were characterized by transmission electron microscopy （TEM）. The results show that the value of peak hardness is increased, while the time to reach the peak hardness is reduced under an external stress. Meanwhile, the length of S（Al2CuMg） phase is shorter and the number density of S phases is larger in the creep-aged alloy. The predominant contribution to the peak hardness can be ascribed to the GPB zones with an elastic stress.
