ME／EXOSAT银道扫描数据的直接解调成像   总被引：5，自引：0，他引：5  

卢方军  李惕碚 《天文学报》1997,38(1):56-66

利用对象重建的直接解调方法，我们对EXOSAT卫星ME探测器银道扫描观测数据进行了重新分析，研究了在以往的分析中难以分辨的几个天区中的分立X射线源．利用Bootstrap方法，我们对成像结果进行了统计误差分析，给出了点源位置和流强的误差．  相似文献   

BPM授时台至南极长城站短波场强测试分析          下载免费PDF全文

杜军虎  孙宪儒 《极地研究》1990,2(3):53-56

本文讨论了在南极长城站收测BPM授时台时号场强的实验数据并和国际广播行政大会推荐的计算方法得到的预测值进行了比较。结果表明,在此条电路上两者较吻合,均方根偏差为6.9dBμv/m,从而在实验上初步验证了FTZ方法的可用性。  相似文献   

海原西华山地区金矿化的地球化学特征及成因     

李厚民  孙继东  王崇礼  刘继庆 《地球科学与环境学报》1997,(2)

本文通过微量元素、硫同位素、氧同位素及矿物流体包裹体研究等方法首次对宁夏海原西华山地区金矿化的地球化学特征进行了探讨，提出了地层、构造及岩浆活动三者联合控矿的成因认识。这一认识无疑对宁夏为数不多的有色金属矿化区之一──宁夏海原西华山地区的金矿的找矿预测具有实际意义。  相似文献   

多时间序列求关联维D_2     

吴云  周硕愚  孙建中  施顺英 《大地测量与地球动力学》1995,(1)

在利用Ｇ．Ｐ．法由单一时间序列计算关联维Ｄ_２的基础上，引入矩阵范数，提出了多时间序列数据联合计算关联维Ｄ_２的算法。这一算法是Ｇ．Ｐ．法的推广。验算结果表明这一算法正确、可行，能提高计算结果的可靠性。  相似文献   

Interannual and seasonal variation of the Huanghe (Yellow River) water discharge over the past 50 years: Connections to impacts from ENSO events and dams   总被引：4，自引：2，他引：2  

Houjie Wang  Zuosheng Yang  Yoshiki Saito  J. Paul Liu  Xiaoxia Sun   《Global and Planetary Change》2006,50(3-4):212-225

The Huanghe, the second largest river in China, is now under great pressure as a water resource. Using datasets of river water discharge, water consumption and regional precipitation for the past 50 years, we elucidate some connections between decreasing water discharges, global El Niño/Southern Oscillation (ENSO) events and anthropogenic impacts in the drainage basin. Global ENSO events, which directly affected the regional precipitation in the river basin, resulted in approximately 51% decrease in river water discharge to the sea. The degree of anthropogenic impacts on river water discharge is now as great as that of natural influences, accelerating the water losses in the hydrological cycle. The large dams and reservoirs regulated the water discharge and reduced the peak flows by storing the water in the flood season and releasing it in the dry season as needed for agricultural irrigation. Thus, as a result, large dams and reservoirs have shifted the seasonal distribution patterns of water discharge and water consumption and finally resulted in rapidly increasing water consumption. Meanwhile, the annual distribution pattern of water consumption also changed under the regulation of dams and reservoirs, indicating that the people living in the river basin consume the water more and more to suit actual agricultural schedule rather than depending upon natural pattern of annual precipitation. The combination of the increasing water consumption facilitated by the dams and reservoirs and the decreasing precipitation closely associated with the global ENSO events over the past half century has resulted in water scarcity in this world-famous river, as well as in a number of subsequent serious results for the river, delta and coastal ocean.  相似文献   

Identification of Phase and Sex-related ISSR Markers of Red Alga Gracilaria lemaneiformis   总被引：1，自引：0，他引：1  

SUN Xue ZHANG Xuecheng MAO Yunxiang SUI Zhenghong QIN Song 《中国海洋大学学报(英文版)》2006,5(1):82-84

Six ISSR primers are employed to display the polymorphism of different phases and sexes of red alga Gracilaria lemaneiformis, and two of them, P1 and P3, amplified distinct band patterns. The ISSR pattern amplified by primer P1 of the female gametophyte is identical to that of tetrasporophyte, but distinct from that of male gametophyte. Of the bands produced by primer P3, one is specific to female gametophyte. Three morphologically similar fronds can be easily identified using ISSR technique. Two specific markers, SM1 and SF3, related to male gametophyte and female gametophyte, are cloned and sequenced. The homologous sequences of SM1 are found to encode a hypothetical protein. There is no homologous sequence of SF3 that can be found in GenBank.  相似文献   

Magneto-induced Line Broadening of Magneto-sensitive Lines in Solar Magnetized Atmospheres     

Zhong-Quan Qu  Shuai Wang  Cheng-Lin Xu  XiaoYu Zhang  Ming-Guo Sun  Chun-Lan Jin National Astronomical Observatories/Yunnan Astronomical Observatory  Chinese Academy of Sciences  Kunming  zqqu@vip.km.net Graduate School of the Chinese Academy of Sciences  Beijing 《中国天文和天体物理学报》2005,5(4):426-432

We analyze the spectral line broadening of those magneto-sensitive lines in solar magnetized atmospheres. The broadening at the line wings is due to the increase of the effective width of energy levels involved in Zeeman splitting, and the broadening at the line core also originated in Zeeman splitting under the condition that the Zeeman components are mixed. Therefore, the magnetoinduced or Zeeman broadening take effects on the whole line. The observed Stokes parameter data in a sunspot and outside it acquired by Solar Stokes Spectrum Telescope (S3T) are analyzed for the demonstration of this mechanism, and the Zeeman broadening rates are calculated for FeI6302.5 under some assumptions. Our result shows that the broadening is increased as the magnetic field strength becomes stronger, but the rate of increase at the line core is decreased as the field strength increases, while the rate at the wing does not show such an obvious regularity. The broadening is more effective in the line core than in the wings.  相似文献   

会计电算化在测绘单位管理中的组织与实施     

孙毅 《地理信息世界》2002,(2)

会计基础工作是财会工作的基本环节 ,是经济管理的重要基础。实现会计电算化对于加强会计基础工作 ,保证财会工作科学有效地进行 ,减少工作误差 ,实现会计工作现代化操作及现代化管理具有现实意义  相似文献   

The excitation mechanism of the interstellar 6.7 GHz methanol maser     

Han-peng Liu  Jin Sun 《Chinese Astronomy and Astrophysics》1997,21(4):438-442

We notice that the second kind of astronomical methanol maser with strong emission always coexists at both 6.7 GHz and 12.2 GHz and in association with compact H II regions and we are led to propose a new excitation mechanism —maser amplification of the 6.7 GHz maser wothout population inversion. We show that this mechanism is compatible with the astronomical conditions and that it and other mechanisms are not mutually exclusive, rather it may serve as a useful complement.  相似文献   

应用能量色散X荧光衍射仪分析海绵元素组成          下载免费PDF全文

李斌  靳艳  赵权宇  孙黎明  虞星炬  金美芳  张卫 《海洋科学》2008,32(8):44-47

通过能量色散X荧光衍射仪（EDXRF）对3种南海潮间带海绵：细薄星芒海绵Stelletta tenui（Lindgren）、澳大利亚厚皮海绵Craniella australiensis （Carter）和多皱软海绵Halichondria hugosa （Ridley＆Dendy）的元素组成和含量进行了研究，并与两种黄海潮间带海绵进行了比较。结果表明，海绵体内的元素组成受种属差异的影响较大，溴元素的含量可能同一定的活性物质产生相关。另外，不同海绵具有骨针形态的多样性，为深入研究内部合成机制提供了材料。  相似文献