Multi-wavelength Diagnostics of Bombardment by Non-thermal Particles in Solar Flares     

Zhi Xu  Cheng Fang  Wei-Qun Can Astronomy Department of Nanjing University  Nanjing  Purple Mountain Observatory  Chinese Academy of Sciences  Nanjing 《中国天文和天体物理学报》2005,5(5):519-530

Chromospheric lines, including Ha, Lyα, Lyβand CaⅡK, CaⅡ8542, are systemically and quantitatively investigated with respect to the non-thermal excitation and ionization due to particle beam bombardment for a series of solar semi-empirical atmospheric models. As a result we propose to use the contrast in the integrated intensity of hydrogen lines to estimate the total energy flux of the bombarding beam during the solar flare impulsive phase. Partial frequency redistribution is considered in the Lyαline calculation and a smaller intensity enhancement in the Ha line-centers is found than in the previous results of Fang et al.  相似文献   

A numerical model for Type II supernovae — The collapse stage     

Cong Xu  Zong-wei Li  Yun-zao Ge 《Chinese Astronomy and Astrophysics》1985,9(2):154-158

We use the following numerical model for the collapse stage of a Type II supernova of 15 M_⊙. Our electron capture rate includes the effects of the inverse reaction and the neutron-proton mass difference. This decreases the electron density at the collapse stage and led to rather large values of the maximum inward velocity and of the corresponding mass (Umax = 3.06 × 10⁹cm/s, Mmax=0.76 M_⊙). These larger values are more favourable for the propagation of shock after the rebounce and the triggering-off of a Type-II supernova explosion. For neutrino transport, we use a leakage model and an equilibrium diffusion model, respectively, for the thin and thick stages and a grey atmosphere model to assess the effect of neutrino precipitation on the collapse. We found this effect to be small, the energy precipitation to be not more than 10^?5 the neutrino energy loss and the momentum precipitation not more than 10^?6 the gravitational acceleration.  相似文献   

局部大地水准面精化系统软件的设计与实现     

田晋 《武汉大学学报(信息科学版)》2009,34(1)

给出了局部大地水准面精化系统的总体结构以及各分系统的详细设计与实现方法,开发了旨在对相关重力测量数据实现自动化处理的局部大地水准面精化系统工具软件,并应用于某区域实际大地水准面的精确计算。实践证明,该系统能有效提高相关数据的处理效率,有助于局部大地水准面精化过程的规范化。  相似文献   

Observational constraints on the radio and γ-ray emission regions of PSR B1055−52     

H. G. Wang  G. J. Qiao  R. X. Xu  Y. Liu 《Monthly notices of the Royal Astronomical Society》2006,366(3):945-952

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Observational evidence for solar coronal decimetric radio pulsations with very short periods     

Xie Rui-xiang  Wang Min  Shi Shuo-biao  Xu Chun  Li Wei-hua  Yan Yi-hua 《Chinese Astronomy and Astrophysics》2003,27(4):426-434

Using the decimetric (700–1500 MHz) radio spectrometer and the synchronous observational system with high temporal resolution at four frequencies (1420, 2130, 2840 and 4260 MHz) of Yunnan Observatory, two rare events were observed on 2001 June 24 and 1990 July 30. The former was a small radio burst exhibiting pulsations with short periods (about 29, 40 and 100 ms) in the impulsive phase. The latter was a large radio burst, which at 2840 MHz produced radio pulsations with period of about 30 ms. This paper focuses on pulsations with very short periods in the range of 29–40 ms. The mechanism of generation of such pulsations may be modulation of radio radiation by the periodic trains of whistler packets originating in unstable regions of the corona. Alternatively, these pulsations can be attributed to wave-wave non-linear interactions of electrostatic upper hybrid waves driven by beams of precipitating electrons in flaring loops.  相似文献   

GPS测量技术在海阳市城区控制中的应用研究          下载免费PDF全文

车谦刚  徐万祥  沈婷  王丰科 《山东国土资源》2008,24(6)

通过海阳市城区D级GPS控制网的布设，探讨了GPS控制网的布网方法和要求，阐述了GPS外业观测的质量控制措施，基线处理方法及其精度检验，讨论了已知控制点的选用方法，以及平差中应注意的问题等。  相似文献   

利用自回归模型检测地球极移重力效应     

杨学峰  孙和平  徐建桥 《大地测量与地球动力学》2004,24(2):110-114

同时采用4个台站的国际超导重力仪长期连续重力观测资料和国际地球自转服务中心提供的同步地球自转参数，研究了极移引起的地球重力场变化特征。利用自回归模型估计了各序列的功率谱密度和积谱密度，结果表明极移导致的重力效应的主要能量集中在Chandler摆动和周年项附近，叠积后实际重力观测与极移重力信号理论值之间的差异分别为0．4％和3．9％，说明超导重力仪可有效监测极移导致的重力变化。  相似文献   

层序-岩相古地理图及其编制   总被引：24，自引：3，他引：21  

田景春  陈洪德  覃建雄  侯中健  侯明才  彭军 《地球科学与环境学报》2004,26(1):6-12

在中国岩相古地理研究历史简要回顾基础上,以层序地层学理论为指导,就如何编制层序-岩相古地理图进行了讨论,首先是编图单元的选择,一是以层序内的体系域为成图单元,二是以相关界面为成图单元.具体方法是在对所研究的层位进行精细的层序地层分析的基础上,进行层序对比,建立等时地层格架.在上述基础上系统编制不同层序内的各体系域或有关界面沉积时的古地理图.以此方法所编制的层序-岩相古地理图具有重要的理论和现实意义,主要表现为更具有等时性、成因连续性和实用性,能更好地反映一个地区在统一地质作用场中的各种地质信息和综合效应;可以揭示出一些新的地质现象,对于覆盖区相带展布及变化具更合理的预测性.进而以中国南方二叠纪为例,在层序划分、对比的基础上,系统编制了一个完整的海平面变化旋回条件下的层序-岩相古地理图,并描述了其平面展布特点.  相似文献   

桐柏─大别山北麓金矿带地质物化探找矿模型     

韩存强  徐大富  陈录 《河南国土资源》1995,(1)

从桐柏─大别山成矿带区域地质、地球物理、地球化学特征的研究入手，分析与金成矿有关的地层、构造、岩浆岩等控矿因素的地球物理场及地球化学特征；建立区域金矿找矿模型。  相似文献   

西宁盆地泥石流类型及其防治意见     

洪文之  徐旭 《青海国土经略》1997,(1)

概略地叙述了西宁地区的泥石流形成条件和形成机理,并将西宁地区泥石流划分为稀性泥石流类及泥石质泥石流种类。在此基础上提出防治泥石流灾害的意见。  相似文献