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71.
For the rising branch of Cycle 22, 1987 January—1989 November, we plot the daily total flux S at each of the five wavelengths 2.0, 3.4, 6.0, 10.7 and 21.2 cm against the apparent sunspot area of the dominant sunspot Ay and find that, for several large active areas, the locus is located below the average regression line, and the increase in the radio flux is insignificant compared to the increase in the sunspot area. 相似文献
72.
X. Hernández Vladimir Avila-Reese Claudio Firmani 《Monthly notices of the Royal Astronomical Society》2001,327(1):329-338
We use a cosmological galactic evolutionary approach to model the Milky Way. A detailed treatment of the mass aggregation and dynamical history of the growing dark halo is included, together with a self-consistent physical treatment for the star formation processes within the growing galactic disc. This allows us to calculate the temporal evolution of star and gas surface densities at all galactic radii, in particular, the star formation history (SFH) at the solar radius. A large range of cosmological mass aggregation histories (MAHs) is capable of producing a galaxy with the present-day properties of the Milky Way. The resulting SFHs for the solar neighbourhood bracket the available observational data for this feature, the most probable MAH yielding the optimal comparison with these observations. We also find that the rotation curve for our Galaxy implies the presence of a constant density core in its dark-matter halo. 相似文献
73.
本文提出了处理分离的太阳活动体光谱不对称轮廓的一种方法──“多云模型”方法。在某些假设和一定的近似条件下利用本文提出的方法可同时得到太阳多个分离活动体的视向速度V,多普勒线宽△λ_D和线心光学深度τ_0,源函数S的近似值。文章给出了该方法的几个应用实例并进行了讨论。研究表明,计算所得的V和△λ_D的值是较为可靠的,二云模型是处理由两个分离活动体沿视线重叠而产生的不对称轮廓较为有效的方法。 相似文献
74.
八世纪前中国纪时日食观测和地球转速变化 总被引:1,自引:0,他引:1
本文对中国正史记载的八世纪前的34次纪时日食观测作了分析,指出其中两次日食记载有重复,另一次纪日不确。对32次日食观测记录的14个食分和45个见食时刻作了考查,其中除一次食甚时刻误差较大(约1^h)外,余皆准确可靠。本文据此对地球自转速率的长期变化趋势作了探讨。 相似文献
75.
A theory for the long-term variations in the orbit of a spherically symmetric satellite due to direct solar radiation pressure is tested using two satellite orbit analyses. The first of these analyses is in terms of mean elements for the balloon satellite Explorer 19. The results are compared with the expected theoretical variations with short-period terms omitted. The second analysis utilises satellite laser ranging observations of the geodetic satellite, Lageos. A novel long-term analysis technique is developed primarily for laser ranging studies. The technique is tested along with the solar radiation pressure perturbation theory by comparing the results from the theory and the analysis. 相似文献
76.
Yatendra Pal Singh Munendra Singh Badruddin 《Journal of Astrophysics and Astronomy》2006,27(2-3):361-366
The problem of solar wind-magnetosphere coupling is investigated for intense geomagnetic storms (Dst < -100nT) that occurred
during solar cycle 23. For this purpose interplanetary plasma and field data during some intensely geo-effective transient
solar/interplanetary disturbances have been analysed. A geomagnetic index that represents the intensity of planetary magnetic
activity at subauroral latitude and the other that measures the ring current magnetic field, together with solar plasma and
field parameters (V, B, Bz, σB, N, and T) and their various derivatives (BV,-BVz, BV2, -BzV2, B2V, Bz2V, NV2) have been analysed in an attempt to study mechanism and the cause of geo-effectiveness of interplanetary manifestations
of transient solar events. Several functions of solar wind plasma and field parameters are tested for their ability to predict
the magnitude of geomagnetic storm. 相似文献
77.
Atsuto Suzuki 《Earth, Moon, and Planets》2006,99(1-4):359-368
The KamLAND liquid scintillator detector demonstrated the detection of antineutrinos produced by natural radioactivities in
the Earth, so-called geoneutrinos. Although this first result of geoneutrinos is consistent with current geophysical models,
more accurate measurements are essential to provide a new window for exploring the inside of the Earth. In this article I
would like to discuss the future prospects of KamLAND geoneutrino detection, and the possibility of directional measurement
of incoming geoneutrinos. It is interesting to consider the application of geoneutrino detectors to measurements of other
neutrino signals. The possibility of detecting the solar 7Be, pep and CNO neutrinos is discussed. A new type detector concept
is proposed not only to explore the precise measurement of reactor neutrino oscillations but also to enable us to realize
the neutrino tomography inside the Earth. 相似文献
78.
79.
We consider the kinetic problem of charged-particle acceleration in a magnetic trap with converging magnetic mirrors. We show that for a positive electrostatic potential of the trap plasma relative to the mirrors, the efficiency of confinement and acceleration increases for electrons and decreases for ions. 相似文献
80.
古本《竹书纪年》记载有:“周昭王十九年,天大噎,雉兔皆震,丧六师于汉。”这与阴天发生的日全食现象十分相似。事件发生在昭王末年南征荆楚的过程中,地点应当在从周都到洞庭湖以南之间的某处。由前人的研究可知昭王十九年应在公元前1010。940年之间。在充分讨论了天文计算的不确定性后得到这一地区可见的9次大食分日食,其中公元前1009和976年的两次日食可能在洞庭湖以南造成日全食,其他地点也都有相当大的食分。在对夏商周断代工程得到的西周年表作微小调整后,昭王十九年天大睦可以认定为公元前976年5月31日日全食。这对“夏商周断代工程”所定出的昭王前后年代是一个独立的支持。 相似文献