In this study, we provide the first detailed analysis of variations in the spacecraft potential (Vs) of the three Swarm satellites, which are flying at about 400-500 km. Unlike previous studies that have investigated ...In this study, we provide the first detailed analysis of variations in the spacecraft potential (Vs) of the three Swarm satellites, which are flying at about 400-500 km. Unlike previous studies that have investigated extreme charging events, usually with spacecraft potentials as negative as −100 V, this study is focused on variations of Swarm Vs readings, which fall within a few negative volts. The Swarm observations show that spacecraft at low Earth orbital (LEO) altitudes are charged only slightly negatively, varying between −7 V and 0 V, with the majority of recorded potentials at these altitudes clustering close to −2 V. However, a second peak of Vs data is found at −5.5 V, though the event numbers for these more-negative observations are less, by an order of magnitude, than for incidents near the −2 V peak. These two distinct Vs peaks suggest two different causes. We have thus divided the Swarm spacecraft Vs data into two categories: less-negatively charged (−5 < Vs < 0 V) and more-negatively-charged (−6.5 < Vs < −5 V). These two Vs categories exhibit different spatial and temporal distributions. The Vs observations in the first category remain relatively closer to 0 V above the magnetic equator, but become much more negative at low and middle latitudes on the day side;at high latitudes, these first-category Vs readings are relatively more-negative during local summer. Second-category Vs events cluster into two bands at the middle latitudes (between ±20°-50° magnetic latitude), but with slightly more negative readings at the South Atlantic Anomaly (SAA) region;at high latitudes, these rarer but more-negative second-category Vs events exhibit relatively more-negative values during local winter, which is opposite to the seasonal pattern seen in the first category. By comparing Vs data to the distributions of background plasma density at Swarm altitudes, we find for the first category that more-negative Vs readings are recorded at regions with higher background plasma density, while for the second category the more-negative Vs data are observed at regions with lower background plasma density. This can be explained as follows: the electron and ion fluxes incident on Swarm surface, whose differences determine the potential of Swarm, are dominated by the background “cold” plasma (due to ionization) and “hot” plasma (due to precipitated particles from magnetosphere) for the two Vs categories, respectively.展开更多
Objective To observe the impacts of acupuncture on brainstem evoked potentials in the patients with primary depression. Methods Forty cases of primary depression were treated by acupuncture at Baihui （百会 GV 20）, Y...Objective To observe the impacts of acupuncture on brainstem evoked potentials in the patients with primary depression. Methods Forty cases of primary depression were treated by acupuncture at Baihui （百会 GV 20）, Yinatng （印堂 GV 29）, DazhuT （大椎 GV 14）, bilateral Shenmen （神门 HT 7）, bilateral Taichong （太冲 LR 3）, bilateral Neiguan （内关 PC 6） and SanyTnjiao （三阴交 SP 6）. The needles were retained for 30 min. Acupuncture treatment was given once every two days, three treatments a week. The brainstem auditory evoked potential （BAEP） and visual evoked potential （VEP） were observed in 6 weeks of treatment. The change in Hamilton depression scale （HAMD） score was observed before and after treatment in the depression group. Results After treatment, VEP wave latency was shortened significantly in patients of depression （P〈0.05）, BAEPIII wave latency was shortened significantly （P〈0.05）. The score of HAMD was decreased apparently in the depression group （P〈0.05）. Conclusions The stressability of visual and auditory stimuli in the central nervous system was decreased in the patients of depression. Acupuncture shortens remarkably the brainstem evoked potentials latency in the patients of depression and achieves the effective results in the treatment of primary depression.展开更多
Understanding mechanical behaviors influenced by electric potential and tribological contacts is important for verifying the robustness and reliability of applications based on metallic porous nanostructures in electr...Understanding mechanical behaviors influenced by electric potential and tribological contacts is important for verifying the robustness and reliability of applications based on metallic porous nanostructures in electrical stimulations.In this work,nickel-based metallic porous nanostructures were studied to characterize their mechanical properties and morphologically dependent contact areas during application of an electric potential using a nanoindenter.W e observed that the indentation moduli of nickel-based metallic porous nanostructures were altered by pore size and application of electric potential.In addition,the structural aspects of the surface morphology of nickel-based porous nanostructures had a critical effect on the determination of contact area.W e suggest that the relation between electric potential and the mechanical behaviors of metallic porous nanostructures can be crucial for building mechanically robust functional devices,which are influenced by electric potential.The morphological shape characteristics of metallic porous nanostructures can be alternative decisive factors for manipulation of tribological performance through regulation of contact area.展开更多
基金supported by the National Key R&D Program of China (Grant No. 2022YFF0503700)the special found of Hubei Luojia Laboratory (220100011)supported by the Dragon 5 cooperation 2020-2024 (project no. 59236)
文摘In this study, we provide the first detailed analysis of variations in the spacecraft potential (Vs) of the three Swarm satellites, which are flying at about 400-500 km. Unlike previous studies that have investigated extreme charging events, usually with spacecraft potentials as negative as −100 V, this study is focused on variations of Swarm Vs readings, which fall within a few negative volts. The Swarm observations show that spacecraft at low Earth orbital (LEO) altitudes are charged only slightly negatively, varying between −7 V and 0 V, with the majority of recorded potentials at these altitudes clustering close to −2 V. However, a second peak of Vs data is found at −5.5 V, though the event numbers for these more-negative observations are less, by an order of magnitude, than for incidents near the −2 V peak. These two distinct Vs peaks suggest two different causes. We have thus divided the Swarm spacecraft Vs data into two categories: less-negatively charged (−5 < Vs < 0 V) and more-negatively-charged (−6.5 < Vs < −5 V). These two Vs categories exhibit different spatial and temporal distributions. The Vs observations in the first category remain relatively closer to 0 V above the magnetic equator, but become much more negative at low and middle latitudes on the day side;at high latitudes, these first-category Vs readings are relatively more-negative during local summer. Second-category Vs events cluster into two bands at the middle latitudes (between ±20°-50° magnetic latitude), but with slightly more negative readings at the South Atlantic Anomaly (SAA) region;at high latitudes, these rarer but more-negative second-category Vs events exhibit relatively more-negative values during local winter, which is opposite to the seasonal pattern seen in the first category. By comparing Vs data to the distributions of background plasma density at Swarm altitudes, we find for the first category that more-negative Vs readings are recorded at regions with higher background plasma density, while for the second category the more-negative Vs data are observed at regions with lower background plasma density. This can be explained as follows: the electron and ion fluxes incident on Swarm surface, whose differences determine the potential of Swarm, are dominated by the background “cold” plasma (due to ionization) and “hot” plasma (due to precipitated particles from magnetosphere) for the two Vs categories, respectively.
文摘Objective To observe the impacts of acupuncture on brainstem evoked potentials in the patients with primary depression. Methods Forty cases of primary depression were treated by acupuncture at Baihui （百会 GV 20）, Yinatng （印堂 GV 29）, DazhuT （大椎 GV 14）, bilateral Shenmen （神门 HT 7）, bilateral Taichong （太冲 LR 3）, bilateral Neiguan （内关 PC 6） and SanyTnjiao （三阴交 SP 6）. The needles were retained for 30 min. Acupuncture treatment was given once every two days, three treatments a week. The brainstem auditory evoked potential （BAEP） and visual evoked potential （VEP） were observed in 6 weeks of treatment. The change in Hamilton depression scale （HAMD） score was observed before and after treatment in the depression group. Results After treatment, VEP wave latency was shortened significantly in patients of depression （P〈0.05）, BAEPIII wave latency was shortened significantly （P〈0.05）. The score of HAMD was decreased apparently in the depression group （P〈0.05）. Conclusions The stressability of visual and auditory stimuli in the central nervous system was decreased in the patients of depression. Acupuncture shortens remarkably the brainstem evoked potentials latency in the patients of depression and achieves the effective results in the treatment of primary depression.
基金This work was supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.NRF-2018R1C1B6002339)by the Chung-Ang University Research Grants in 2017.
文摘Understanding mechanical behaviors influenced by electric potential and tribological contacts is important for verifying the robustness and reliability of applications based on metallic porous nanostructures in electrical stimulations.In this work,nickel-based metallic porous nanostructures were studied to characterize their mechanical properties and morphologically dependent contact areas during application of an electric potential using a nanoindenter.W e observed that the indentation moduli of nickel-based metallic porous nanostructures were altered by pore size and application of electric potential.In addition,the structural aspects of the surface morphology of nickel-based porous nanostructures had a critical effect on the determination of contact area.W e suggest that the relation between electric potential and the mechanical behaviors of metallic porous nanostructures can be crucial for building mechanically robust functional devices,which are influenced by electric potential.The morphological shape characteristics of metallic porous nanostructures can be alternative decisive factors for manipulation of tribological performance through regulation of contact area.
