提出一种基于改进YOLOv8n的苹果叶片病害识别与检测方法,以提升检测精度与效率.首先将主干网络的C2f模块替换为空间和通道重建卷积(Spatial and Channel Reconstruction Convolution,SCConv),以提高参数利用率并增强病害区域特征的提取...提出一种基于改进YOLOv8n的苹果叶片病害识别与检测方法,以提升检测精度与效率.首先将主干网络的C2f模块替换为空间和通道重建卷积(Spatial and Channel Reconstruction Convolution,SCConv),以提高参数利用率并增强病害区域特征的提取效果;其次,将头部的检测头改为动态检测头(Dynamic Head,Dyhead),使模型能够更精准地检测不同尺度的病害目标;最后,采用Wise-IoUv3(WIoUv3)损失函数优化目标框匹配策略,提高模型在边界框回归上的鲁棒性和精确度.实验结果表明,所提方法与原始YOLOv8相比,均值平均精度mAP@0.5和mAP@0.5:0.95分别提升了1.4%和3.0%,精确度P提高了2.5%.展开更多
A mean-field spin-density wave (SDW) analysis of pseudogap in the underdoped cuprates is proposed on the dependence of the energy gap which mimics the pseudogap near (π, 0) point at least. It implies that the pseudog...A mean-field spin-density wave (SDW) analysis of pseudogap in the underdoped cuprates is proposed on the dependence of the energy gap which mimics the pseudogap near (π, 0) point at least. It implies that the pseudogap structure near (π, 0) is not sensitive to the long-range order and will survive leading to the pseudogap phenomenon in the underdoped metallic phase. On the other hand, in the long-range ordering antiferromagnetic region, the mean-field SDW theory holds and the pseudogap structure predicated by the theory should be observable experimentallyv. Then one prediction is that the pseudogap would smoothly extrapolate between itinerant antiferromagnetic phase and underdoped metallic phase.展开更多
By using density matrix renormalization group （DMRG） method a model for organic molecule-based ferromagnetic chain is proposed. It is found that the ground states of Undoped and doped systems both exhibit ferrimagne...By using density matrix renormalization group （DMRG） method a model for organic molecule-based ferromagnetic chain is proposed. It is found that the ground states of Undoped and doped systems both exhibit ferrimagnetic ordering. The e-e repulsion plays an important role in the stability of the ferromagnetic state either in doped system or undoped system. For the undoped system, each unit cell coatains half of the total spins, which is consistent with Lieb＇s theorem. It is convinced that when the system is doped with one electron, a charge density wave is excited, which decreases the amplitude of spin density wave,therefore acting against the stability of ferromagnetic state.展开更多
文摘A mean-field spin-density wave (SDW) analysis of pseudogap in the underdoped cuprates is proposed on the dependence of the energy gap which mimics the pseudogap near (π, 0) point at least. It implies that the pseudogap structure near (π, 0) is not sensitive to the long-range order and will survive leading to the pseudogap phenomenon in the underdoped metallic phase. On the other hand, in the long-range ordering antiferromagnetic region, the mean-field SDW theory holds and the pseudogap structure predicated by the theory should be observable experimentallyv. Then one prediction is that the pseudogap would smoothly extrapolate between itinerant antiferromagnetic phase and underdoped metallic phase.
基金the National Natural Science Foundation of China under
文摘By using density matrix renormalization group （DMRG） method a model for organic molecule-based ferromagnetic chain is proposed. It is found that the ground states of Undoped and doped systems both exhibit ferrimagnetic ordering. The e-e repulsion plays an important role in the stability of the ferromagnetic state either in doped system or undoped system. For the undoped system, each unit cell coatains half of the total spins, which is consistent with Lieb＇s theorem. It is convinced that when the system is doped with one electron, a charge density wave is excited, which decreases the amplitude of spin density wave,therefore acting against the stability of ferromagnetic state.
