Background: Pattern hair loss (PHL) is the most common form of hair loss affecting both men and women. The occipital region, located at the back of the scalp, has been considered resistant to hair loss in PHL. It is o...Background: Pattern hair loss (PHL) is the most common form of hair loss affecting both men and women. The occipital region, located at the back of the scalp, has been considered resistant to hair loss in PHL. It is often used as a donor site for hair transplantation procedures. However, evidence suggests that the occipital region may also be affected by PHL, although to a lesser extent compared to the frontal and vertex regions. Objective: To assess the levels and determinants of occipital involvement in PHL, focusing on gender and disease severity. Such data would enhance the comprehensive understanding of PHL progression and inform development of improved treatment strategies. Methods: This retrospective study involved 1993 adults (1000 males, 993 females) following for PHL at a specialized hair clinic in Jeddah, Saudi Arabia. Any patient who had hair transplantation in the past and any male who had balding areas (Hamilton-Norwood scales 4 to 7) at the initial consultation was excluded. The primary outcome was occipital involvement, defined as >10% thin hairs in the trichometry assessments of the occipital region. Additional data included patients age, treatment status, disease severity, and other trichometry parameters. Results: The prevalence of occipital involvement was found to be 23.8% overall, significantly more frequent in females (35.6%) than males with early PHL (Hamilton-Norwood scales 2 and 3) (12.1%) (p Conclusion: This study underscored the relevance of gender and disease severity in occipital involvement in PHL. Females had significantly higher rates of occipital involvement, suggesting that gender differences are critical in understanding PHL progression. Future research should aim to validate these findings, with an aim to refine therapeutic and surgical approaches to improve patient outcomes.展开更多
现有深度强化学习(deep reinforcement learning,DRL)方法在解决配电网电压优化问题时,存在信用分配难、探索效率低等问题,在模型训练速度和优化效果等方面表现欠佳。为此,结合配电网分区降损与模仿学习的思想,提出一种基于指导信号的...现有深度强化学习(deep reinforcement learning,DRL)方法在解决配电网电压优化问题时,存在信用分配难、探索效率低等问题,在模型训练速度和优化效果等方面表现欠佳。为此,结合配电网分区降损与模仿学习的思想,提出一种基于指导信号的多智能体深度确定性策略梯度(guidance signal based multi-agent deep deterministic policy gradient,GS-MADDPG)的电压优化方法。首先,将电动汽车(electric vehicles,EV)集群、分布式电源(distributed generations,DG)和无功调节装置作为决策智能体,构建强化学习优化模型。然后,通过配电网分区,解耦多智能体的外部奖励,并结合模仿学习,利用指导信号引入内部奖励,帮助智能体快速寻优。最后,基于改进IEEE33节点系统进行算例测试。结果表明,所提电压优化策略较传统DRL方法具有更高的样本利用率,实现了更稳定的收敛及更高的模型训练效率,提升了配电网电压的优化效果。展开更多
The oxidation microstructure and maximum energy product （BH）max loss of a 8m（Co0.76, Fe0.1, Cu0.1, Zr0.04）7 magnet oxidized at 500 ℃ were systematically investigated. Three different oxidation regions were formed...The oxidation microstructure and maximum energy product （BH）max loss of a 8m（Co0.76, Fe0.1, Cu0.1, Zr0.04）7 magnet oxidized at 500 ℃ were systematically investigated. Three different oxidation regions were formed in the oxidized magnet： a continuous externM oxide scale, an internal reaction layer, and a diffusion zone. Both room-temperature and high-temperature （BH）max losses exhibited the same parabolic increase with oxidation time. An oxygen diffusion model was proposed to simulate the dependence of （BH）max loss on oxidation time. It is found that the external oxide scale has little effect on the （BH）max loss, and both the internal reaction layer and diffusion zone result in the （BH）max loss. Moreover, the diffusion zone leads to more （BH）max loss than the internal reaction layer. The values of the oxidation rate constant k for internal reaction layer and oxygen diffusion coefficient D for diffusion zone were obtained, which are about 1.91×10^-10 cm^2/s and 6.54×10^-11 cm^2/s, respectively.展开更多
There is a coupling of thermal, mechanical, chemical and fluidal processes in a continental shear zone. Both Xincheng - Xishui and Hetai shear zones are typical continental crust shear zones of greenschist facies envi...There is a coupling of thermal, mechanical, chemical and fluidal processes in a continental shear zone. Both Xincheng - Xishui and Hetai shear zones are typical continental crust shear zones of greenschist facies environment. The representative mylonite zones of the shear zones are studied with whole rock major and trace element analyses. The chemical compositional variation tendencies in both shear zones are very similar and the gain - loss ratios of various components in the mylonitic rocks are reflected in the mass balance equations. The enrichment of those immobile high - field- strengh elements is considered to be related to the volume loss of the mylonitic rocks in a shear zone. Based on the volume loss expression Cs /Co = 1/(1- V), the fractional volume losses (V) are 37.5% and 36.5%-42.3% respectively for mylonites and ultramylonites in the Xincheng-Xishui shear zone and 11 % and 28% respectively for mylonites and phyllonites in the Hetai shear zone. The high volume loss and large removal of SiO2 from the system imply that there is a large amount of percolating fluids in the shear zones. From the SiO2 loss, the fluid/rock ratios (N) are calculated as Nmyl = 113 - 563, Nultramyl= 133-664 for the Xincheng-Xishui shear zone and Nmyl=42-208, Nphyl=110-550 for the Hetai shear zone. Such a large amount of percolating fluid must have profoundly affected the rheological behavior, chemical behavior and metallogenesis of the shear zones.展开更多
文摘Background: Pattern hair loss (PHL) is the most common form of hair loss affecting both men and women. The occipital region, located at the back of the scalp, has been considered resistant to hair loss in PHL. It is often used as a donor site for hair transplantation procedures. However, evidence suggests that the occipital region may also be affected by PHL, although to a lesser extent compared to the frontal and vertex regions. Objective: To assess the levels and determinants of occipital involvement in PHL, focusing on gender and disease severity. Such data would enhance the comprehensive understanding of PHL progression and inform development of improved treatment strategies. Methods: This retrospective study involved 1993 adults (1000 males, 993 females) following for PHL at a specialized hair clinic in Jeddah, Saudi Arabia. Any patient who had hair transplantation in the past and any male who had balding areas (Hamilton-Norwood scales 4 to 7) at the initial consultation was excluded. The primary outcome was occipital involvement, defined as >10% thin hairs in the trichometry assessments of the occipital region. Additional data included patients age, treatment status, disease severity, and other trichometry parameters. Results: The prevalence of occipital involvement was found to be 23.8% overall, significantly more frequent in females (35.6%) than males with early PHL (Hamilton-Norwood scales 2 and 3) (12.1%) (p Conclusion: This study underscored the relevance of gender and disease severity in occipital involvement in PHL. Females had significantly higher rates of occipital involvement, suggesting that gender differences are critical in understanding PHL progression. Future research should aim to validate these findings, with an aim to refine therapeutic and surgical approaches to improve patient outcomes.
文摘现有深度强化学习(deep reinforcement learning,DRL)方法在解决配电网电压优化问题时,存在信用分配难、探索效率低等问题,在模型训练速度和优化效果等方面表现欠佳。为此,结合配电网分区降损与模仿学习的思想,提出一种基于指导信号的多智能体深度确定性策略梯度(guidance signal based multi-agent deep deterministic policy gradient,GS-MADDPG)的电压优化方法。首先,将电动汽车(electric vehicles,EV)集群、分布式电源(distributed generations,DG)和无功调节装置作为决策智能体,构建强化学习优化模型。然后,通过配电网分区,解耦多智能体的外部奖励,并结合模仿学习,利用指导信号引入内部奖励,帮助智能体快速寻优。最后,基于改进IEEE33节点系统进行算例测试。结果表明,所提电压优化策略较传统DRL方法具有更高的样本利用率,实现了更稳定的收敛及更高的模型训练效率,提升了配电网电压的优化效果。
基金Project supported by the National High Technology Research and Development Program of China (Grant No. 2010AA03A401)the National Natural Science Foundation of China (Grant No. 51071010)+1 种基金the Aviation Foundation of China (AFC) (Grant No. 2009ZF51063)the Fundamental Research Funds for the Central Universities
文摘The oxidation microstructure and maximum energy product （BH）max loss of a 8m（Co0.76, Fe0.1, Cu0.1, Zr0.04）7 magnet oxidized at 500 ℃ were systematically investigated. Three different oxidation regions were formed in the oxidized magnet： a continuous externM oxide scale, an internal reaction layer, and a diffusion zone. Both room-temperature and high-temperature （BH）max losses exhibited the same parabolic increase with oxidation time. An oxygen diffusion model was proposed to simulate the dependence of （BH）max loss on oxidation time. It is found that the external oxide scale has little effect on the （BH）max loss, and both the internal reaction layer and diffusion zone result in the （BH）max loss. Moreover, the diffusion zone leads to more （BH）max loss than the internal reaction layer. The values of the oxidation rate constant k for internal reaction layer and oxygen diffusion coefficient D for diffusion zone were obtained, which are about 1.91×10^-10 cm^2/s and 6.54×10^-11 cm^2/s, respectively.
基金The study is sponsored by the National Natural Science Foundation of China (No.49172090 ) and supported by the Open Laboratory of Crust- Mantle Constitution, Recycling and Dynamics of Ministry of Geology and Mineral Resources
文摘There is a coupling of thermal, mechanical, chemical and fluidal processes in a continental shear zone. Both Xincheng - Xishui and Hetai shear zones are typical continental crust shear zones of greenschist facies environment. The representative mylonite zones of the shear zones are studied with whole rock major and trace element analyses. The chemical compositional variation tendencies in both shear zones are very similar and the gain - loss ratios of various components in the mylonitic rocks are reflected in the mass balance equations. The enrichment of those immobile high - field- strengh elements is considered to be related to the volume loss of the mylonitic rocks in a shear zone. Based on the volume loss expression Cs /Co = 1/(1- V), the fractional volume losses (V) are 37.5% and 36.5%-42.3% respectively for mylonites and ultramylonites in the Xincheng-Xishui shear zone and 11 % and 28% respectively for mylonites and phyllonites in the Hetai shear zone. The high volume loss and large removal of SiO2 from the system imply that there is a large amount of percolating fluids in the shear zones. From the SiO2 loss, the fluid/rock ratios (N) are calculated as Nmyl = 113 - 563, Nultramyl= 133-664 for the Xincheng-Xishui shear zone and Nmyl=42-208, Nphyl=110-550 for the Hetai shear zone. Such a large amount of percolating fluid must have profoundly affected the rheological behavior, chemical behavior and metallogenesis of the shear zones.
