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31.
LUO Kai-li LI Bao-sheng ZHU Yi-zhi JIN He-ling ZHANG David Dian YAN Man-cun LI Hou-xin YAO Chun-xia ZHANG Yu-hongf . Department of Geography South China Normal University Guangzhou P. R. China . State Key Labor 《中国地理科学(英文版)》2001,11(4):336-342
About 70years ago,Frenc卜卜alaeohdoglst回LL sc卜dars al卜ome and a卜road卜ave successively con-HARD de Chardin P.et al.Initiated the Quaternary ducted large amount ofwork on the Later Quaternarygeologlcal research In the >alawusu River Basin of strata(TEILHARD,1924; YUAN,1978; LI,1987;desert region of Northern China and established th,ZHENG,1989; SUN et al,1996; LI et al,1993),Salawusu Formation门EILHARD,1924).Sine,then,palaeobiology… 相似文献
32.
We give a summary of the morphology of the two-ribbon flare of 1981 May 13. One striking feature is that the Ha flare began at about 0338' UT and the double-ribbon structure was formed about 0346, the impulsive phase of the radio 3 cm burst at 04 11 UT. The 3 cm radio burst flux beginning at 03 33 UT showed only slow, stepwise increases lasting half an hour until the impulsive phase and this type of increase is usually regarded to be a typical thermal process. Each step in the radio flux corresponded to a variation in the Ha flare, showing that the radio and Hα emissions during this period came from the same thermal source. In this paper, we explain this behaviour in terms of Hyder's model: we think that the magnetic trough supporting the solar prominence rose for some reason, causing the prominence matter (the dark filaments) to fall along the magnetic lines and to hit the chromosphere and trigger off the flare. We give rough estimates of the energy density, the height of prominence and the infall matter at the different radio increments. We also give a qualitative explanation for the appearances of the single-peak structure in the radio burst at 0411 and the covering of the sunspot shortly after at 04 13 and propose several possible mechanisms. 相似文献
33.
To seek nonlinear solutions of force-free magnetic fields, some symmetries or approximations are usually invoked. We consider magnetic fields lying on coordinate surfaces of an orthogonal curvilinear coordinate system. We conclude that only fields on parallel planes or spherical shells can be expressed in the form provided by Low in 1980s. These force-free fields are stable against small perturbations with rigid boundaries. Fields on cylindrical shells are also considered. 相似文献
34.
Chun-sheng Li Qi-jun Fu Yu-hua Yan Shu-ying Jiang Hong-wei Li 《Chinese Astronomy and Astrophysics》1985,9(2):128-133
We propose a model of two acceleration regions, which can explain, on the basis of microwave maser caused by a “hollow-beam” distribution of electrons, the presence of millisecond spikes in the event of 1981 May 16 and their absence in the event of 1981 October 12, and the enhanced continuous emission in the latter. We have also uncovered relations among the features, e.g. the Type IIIG, Type IVDCIM and hard x-ray bursts, that accompany the microwave millisecond spikes during the impulsive phase of a large flare. 相似文献
35.
CLIMATICTRENDINDICATEDBYVARIATIONSOFGLACIERSANDLAKESINTHETIANSHANMOUNTAINS¥HuRuji;YangChuande;MaHong;JiangFengqing(XinjiangIn... 相似文献
36.
我们于1989年11月30日晚对PG0027+260进行了时间分辨率为108秒的高速CCD测光,得到了一条完整的光变曲线,从而确认其为激变食变星系统,轨道周期0.146~d 相似文献
37.
OQ208 is used ore and more frequently as a VLBI calibrator of flux density. A VLBI image of OQ208 at 5 GHz is firstly provided in this paper. Its structure consists of a compact core and a component. The angular distance between the core and the component is about 7 milli-arcsecond; the position angle is −125 degrees. In principle, OQ208 is not an ideal VLBI calibrator of flux density. This paper provides the structural information for correcting the structure effect when OQ208 is to be used as a calibrator. 相似文献
38.
介绍了近年来河外H2O超脉泽的主要观测结果。H2O超脉泽通常起源于活动星系核中央的拱核盘。它们主要寄生在 Serfert 2星系或低电离核区。至今为止,已有20个星系探测到H2O超脉泽。脉泽辐射的各向同性光度为10~6000L⊙。所有超脉泽星系显示出核的活动,显然,脉泽是由核活动所产生的射电和X射线光子或激波来抽运的。H2O超脉泽倾向存在于高倾斜度的星系,这使得沿视线上的分子柱密度增高,产生足够大的放大光深。最有可能产生H2O超脉泽辐射的星系应有一个包含着射电源的侧向的分子盘以及一个适当的抽运机制。 相似文献
39.
40.
Zhu Ge-yan 《中国海洋湖沼学报》1996,14(4):308-315
The composition and distribution of benthic, periphytic and planktonic rotifers in different habitats in Krottensee were investigated.
Sixty-five rotifer taxa were identified, their relative abundance estimated.
Classification of the data set by cluster analysis allowed the recognition of distinct habitat groups confined to acid bog
ponds, macrophytes, sediments and open water. Five groups of rotifer taxa were identified on the basis of their habitat preferences
and the occurrence of the taxa. Highest diversities were found on macrophytes and in acid bog ponds. 相似文献