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211.
Ikkoh Funaki Hidenori Kojima Hiroshi Yamakawa Yoshinori Nakayama Yukio Shimizu 《Astrophysics and Space Science》2007,307(1-3):63-68
To propel a spacecraft in the direction leaving the Sun, a magnetic sail (MagSail) blocks the hypersonic solar wind plasma
flow by an artificial magnetic field. In order to simulate the interaction between the solar wind and the artificially deployed
magnetic field produced around a magnetic sail spacecraft, a laboratory simulator was designed and constructed inside a space
chamber. As a solar wind simulator, a high-power magnetoplasmadynamic arcjet is operated in a quasisteady mode of 0.8 ms duration.
It can generate a simulated solar wind that is a high-speed (above 20 km/s), high-density (1018 m−3) hydrogen plasma plume of ∼0.7 m in diameter. A small coil (2 cm in diameter), which is to simulate a magnetic sail spacecraft
and can obtain 1.9-T magnetic field strength at its center, was immersed inside the simulated solar wind. Using these devices,
the formation of a magnetic cavity (∼8 cm in radius) was observed around the coil, which indicates successful simulation of
the plasma flow of a MagSail in the laboratory. 相似文献
212.
青藏高原那曲地区冰冰雹天气系统中的大气电场 总被引:12,自引:9,他引:3
利用1998年4~9月间进行的GAME-TIBET青堪稿原云和降水的多普勒雷达及大气平均电场加强期观测实验资料,对青藏高原那曲地区的冰雹天气系统中的大民电场作了定量观测和研究。结果表明:在降雹过程中大气电场强度基本上系统中的大气电场强度基本上均为负值,其峰值也均强于-22kVm^-1;在降雹过程中随着降雹时间的临近,大民场强度基本不断增强,但降雹开始时大气电场强度并不达到其峰值,峰值出现的时刻比开 相似文献
213.
利用1998年4~9月间进行的GAME-TIBET青藏高原云和降水的多普勒雷达及大气平均电场加强期观测实验资料, 对青藏高原那曲地区的冰雹天气系统中的大气电场作了定量观测和研究.结果表明: 在降雹过程中大气电场强度基本上均为负值, 其峰值也均强于-22 kVm-1; 在降雹过程中随着降雹时间的临近, 大气电场强度不断增强, 但降雹开始时大气电场强度并未达到其峰值, 峰值出现的时刻比开始降雹的时刻略有滞后; 在各降雹日中, 较强的大气电场强度基本上对应着各冰雹谱分布段较多的冰雹数目, 而这种较好的相关在各谱分布段上都表现出来; 随着降雹时间的临近, 每5 min闪电频数不断增强.在开始降雹时每5 min闪电频数平均达到43, 峰值的出现时刻略滞后于开始降雹的时刻, 这一滞后时间一般平均在3 min左右; 在降雹过程中, 单位面积中的冰雹数目与对应时段内总闪电数有着较好的对数关系, 相关系数R为0.954 0.在降雹过程的时间序列上, 冰雹云成熟期过后, 总闪电次数与冰雹降雹率成反相关. 相似文献
214.
Kenji Ohta Kei Hirose Masahiro Ichiki Katsuya Shimizu Nagayoshi Sata Yasuo Ohishi 《Earth and Planetary Science Letters》2010,289(3-4):497-502
The electrical conductivities of natural pyrolitic mantle and MORB materials were measured at high pressure and temperature covering the entire lower mantle conditions up to 133 GPa and 2650 K. In contrast to the previous laboratory-based models, our data demonstrate that the conductivity of pyrolite does not increase monotonically but varies dramatically with depth in the lower mantle; it drops due to high-spin to low-spin transition of iron in both perovskite and ferropericlase in the mid-lower mantle and increases sharply across the perovskite to post-perovskite phase transition at the D″ layer. We also found that the MORB exhibits much higher conductivity than pyrolite. The depth–conductivity profile measured for pyrolite does not match the geomagnetic field data below about 1500-km depth, possibly suggesting the existence of large quantities of subducted MORB crust in the deep lower mantle. The observations of geomagnetic jerks suggest that the electrical conductivity may be laterally heterogeneous in the lowermost mantle with high anomaly underneath Africa and the Pacific, the same regions as large low shear-wave velocity provinces. Such conductivity and shear-wave speed anomalies are also possibly caused by the deep subduction and accumulation of dense MORB crust above the core–mantle boundary. 相似文献
215.
216.
Thomas Hobiger Seiichi Shimada Shingo Shimizu Ryuichi Ichikawa Yasuhiro Koyama Tetsuro Kondo 《Journal of Atmospheric and Solar》2010,72(2-3):262-270
Space geodetic applications require to model troposphere delays as good as possible in order to achieve highly accurate positioning estimates. However, these models are not capable to consider complex refractivity fields which are likely to occur during extreme weather situations like typhoons, storms, heavy rain-fall, etc. Thus it has been investigated how positioning results can be improved if information from numerical weather models is taken into account. It will be demonstrated that positioning errors can be significantly reduced by the usage of ray-traced slant delays. Therefore, meso-scale and fine-mesh numerical weather models are utilized and their impact on the positioning results will be measured. The approach has been evaluated during a typhoon passage using global positioning service (GPS) observations of 72 receivers located around Tokyo, proving the usefulness of ray-traced slant delays for positioning applications. Thereby, it is possible reduce virtual station movements as well as improve station height repeatabilities by up to 30% w.r.t. standard processing techniques. Additionally the advantages and caveats of numerical weather models will be discussed and it will be shown how fine-mesh numerical weather models, which are restricted in their spatial extent, have to be handled in order to provide useful corrections. 相似文献
217.
James A. Van Orman Timothy L. Grove Nobumichi Shimizu Graham D. Layne 《Contributions to Mineralogy and Petrology》2002,142(4):416-424
Volume diffusion rates of Ce, Sm, Dy, and Yb have been measured in a natural pyrope-rich garnet single crystal (Py71Alm16Gr13) at a pressure of 2.8 GPa and temperatures of 1,200-1,450 °C. Pieces of a single gem-quality pyrope megacryst were polished, coated with a thin layer of polycrystalline REE oxide, then annealed in a piston cylinder device for times between 2.6 and 90 h. Diffusion profiles in the annealed samples were measured by SIMS depth profiling. The dependence of diffusion rates on temperature can be described by the following Arrhenius equations (diffusion coefficients in m2/s): % MathType!MTEF!2!1!+- % feaaeaart1ev0aaatCvAUfKttLearuavTnhis1MBaeXatLxBI9gBam % XvP5wqSXMqHnxAJn0BKvguHDwzZbqegm0B1jxALjhiov2DaeHbuLwB % Lnhiov2DGi1BTfMBaebbfv3ySLgzGueE0jxyaibaieYlf9irVeeu0d % Xdh9vqqj-hEeeu0xXdbba9frFj0-OqFfea0dXdd9vqaq-JfrVkFHe9 % pgea0dXdar-Jb9hs0dXdbPYxe9vr0-vr0-vqpWqaaeaabiGaciaaca % qabeaadaabauaaaOqaauaabeqaeeaaaaqaaiGbcYgaSjabc+gaVjab % cEgaNnaaBaaaleaacqaIXaqmcqaIWaamaeqaaOGaemiraq0aaSbaaS % qaaiabbMfazjabbkgaIbqabaGccqGH9aqpcqGGOaakcqGHsislcqaI % 3aWncqGGUaGlcqaI3aWncqaIZaWmcqGHXcqScqaIWaamcqGGUaGlcq % aI5aqocqaI3aWncqGGPaqkcqGHsisldaqadaqaaiabiodaZiabisda % 0iabiodaZiabgglaXkabiodaZiabicdaWiaaysW7cqqGRbWAcqqGkb % GscaaMe8UaeeyBa0Maee4Ba8MaeeiBaW2aaWbaaSqabeaacqqGTaql % cqqGXaqmaaGccqGGVaWlcqaIYaGmcqGGUaGlcqaIZaWmcqaIWaamcq % aIZaWmcqWGsbGucqWGubavaiaawIcacaGLPaaaaeaacyGGSbaBcqGG % VbWBcqGGNbWzdaWgaaWcbaGaeGymaeJaeGimaadabeaakiabdseaen % aaBaaaleaacqqGebarcqqG5bqEaeqaaOGaeyypa0JaeiikaGIaeyOe % I0IaeGyoaKJaeiOla4IaeGimaaJaeGinaqJaeyySaeRaeGimaaJaei % Ola4IaeGyoaKJaeG4naCJaeiykaKIaeyOeI0YaaeWaaeaacqaIZaWm % cqaIWaamcqaIYaGmcqGHXcqScqaIZaWmcqaIWaamcaaMe8Uaee4AaS % MaeeOsaOKaaGjbVlabb2gaTjabb+gaVjabbYgaSnaaCaaaleqabaGa % eeyla0IaeeymaedaaOGaei4la8IaeGOmaiJaeiOla4IaeG4mamJaeG % imaaJaeG4mamJaemOuaiLaemivaqfacaGLOaGaayzkaaaabaGagiiB % aWMaei4Ba8Maei4zaC2aaSbaaSqaaiabigdaXiabicdaWaqabaGccq % WGebardaWgaaWcbaGaee4uamLaeeyBa0gabeaakiabg2da9iabcIca % OiabgkHiTiabiMda5iabc6caUiabikdaYiabigdaXiabgglaXkabic % daWiabc6caUiabiMda5iabiEda3iabcMcaPiabgkHiTmaabmaabaGa % eG4mamJaeGimaaJaeGimaaJaeyySaeRaeG4mamJaeGimaaJaaGjbVl % abbUgaRjabbQeakjaaysW7cqqGTbqBcqqGVbWBcqqGSbaBdaahaaWc % beqaaiabb2caTiabbgdaXaaakiabc+caViabikdaYiabc6caUiabio % daZiabicdaWiabiodaZiabdkfasjabdsfaubGaayjkaiaawMcaaaqa % aiGbcYgaSjabc+gaVjabcEgaNnaaBaaaleaacqaIXaqmcqaIWaamae % qaaOGaemiraq0aaSbaaSqaaiabboeadjabbwgaLbqabaGccqGH9aqp % cqGGOaakcqGHsislcqaI5aqocqGGUaGlcqaI3aWncqaI0aancqGHXc % qScqaIYaGmcqGGUaGlcqaI4aaocqaI0aancqGGPaqkcqGHsisldaqa % daqaaiabikdaYiabiIda4iabisda0iabgglaXkabiMda5iabigdaXi % aaysW7cqqGRbWAcqqGkbGscaaMe8UaeeyBa0Maee4Ba8MaeeiBaW2a % aWbaaSqabeaacqqGTaqlcqqGXaqmaaGccqGGVaWlcqaIYaGmcqGGUa % GlcqaIZaWmcqaIWaamcqaIZaWmcqWGsbGucqWGubavaiaawIcacaGL % Paaaaaaaaa!0C76!