1992年6月26日Hα耀斑后环的不均匀性和物质运动的可能解释     

尤丹 Schim.  B 《天文学报》1998,39(2):165-171,T001

本文利用电流不稳定性线性理论讨论了１９９２年６月２５日至２６日耀斑后环中出现不均匀“结”状结构（“ｋｎｏｔ”或“ｂｌｏｂ”）的可能性,并且在同时考虑重力、磁力和环顶物质下落初速的情况下,理论计算了１９９２年６月２６日Ｈα耀斑后环物质运动的规律。理论计算与观测求得的视向速度随高度分布的曲线基本符合。  相似文献   

稀有气体在深部地质研究中的意义   总被引：4，自引：0，他引：4  

汤华云  郑建平 《世界地质》2004,23(1):20-27

幔源物质中的稀有气体蕴藏着丰富的地球深部过程信息。它们可对地幔结构、地幔脱气历史、大陆地幔不均一性、幔源岩浆演化和CO2天然气成因等研究提供独特的示踪作用。结合中国东部地幔捕虏体的资料,综述了稀有气体在这些方面的研究进展。研究表明,MORB源和OIB源玄武岩稀有气体组成差异强烈支持地幔双层结构的存在,地幔脱气过程主要受溶解度控制脱气模式(SCD)控制;同时,中国东部地幔存在不均一性可以在稀有气体方面得到印证;郯庐断裂可能为东部幔源无机CO2的脱出提供了良好的通道。  相似文献   

Inhomogeneities in the circumstellar envelope of the A0E herbig star AB aur     

Nina Beskrovnaya  Mikhail Pogodin  Ivan Najdenov  Iosiff Romanyuk 《Astrophysics and Space Science》1995,224(1-2):429-430

Simultaneous high-resolution spectroscopy in H andUBVRI polarimetric observations are proposed as an effective method for the search for circumstellar inhomogeneities in A0-type Herbig stars. The new results for AB Aur are presented as a successful example of the use of this method. The analysis of about 100 CCD H profiles (R = 30 000) and more than 150 polarimetric measurements obtained in January, 1994 allowed to discover a long-lived stream-like inhomogeneity in the circumstellar gaseous envelope.  相似文献   

中国探空位势高度资料的非均一性检验与订正   总被引：1，自引：0，他引：1  

陈哲  吴茜  熊安元  吴宜进 《气象》2013,39(10):1337-1343

利用加拿大环境部气候研究中心研发的PMFT均一化检验方法,结合国家气象信息中心整理的中国区域各探空台站元数据信息,对我国123个探空台站各标准等压面月平均探空位势高度资料进行了非均一性检验和订正。结果表明：仪器换型、探测系统升级以及辐射订正方法改变是造成中国区域月平均探空位势高度资料不均一的主要原因。两个观测时次位势高度序列不均一的台站数随高度的增加而增加。各标准等压面上月平均位势高度序列不均一的探空台站平均订正幅度也随着位势高度的升高而增大。并且两个观测时次各标准等压面位势高度序列均为负订正,表明我国各标准等压面位势高度资料存在系统性偏高的问题。123个探空台站在对流层顶和对流层高层位势高度序列订正前是位势高度降低趋势,订正后位势高度序列呈增高趋势。对流层中低层原始位势高度序列呈增高趋势,订正后这种增高趋势更加明显。  相似文献   

Thermohaline structure inhomogeneity associated with polynia at the northern margin of Emery Ice-shelf     

蒲书箴  葛人峰  董兆乾  于卫东  史久新  项宝强 《极地研究(英文版)》2007,18(1):18-26

Based on the hydrographic data in austral summer during the 22nd Antarctic Expedition of China(2005/2006),some features can be found about the northern margin of Emery ice shelf as follows.The heat content in the surface layer(0-50 m) at the eastern end and the western end of the ice-shelf margin is much higher than that at the middle.The upper mixing-layer depth and the seasonal thermocline depth at the middle of the ice-shelf northern margin are much shallower than those at the both ends.However there is much less difference between the middle and the ends in the bottom layer.The remote sensing photos show that the inhomogeneity in the surface-layer water is closely related to the spatial distribution of the floes and polynia in the area.  相似文献   

Evidence of a laterally variable lower mantle structure from P- and S-waves   总被引：1，自引：0，他引：1  

M. Weber  J. P. Davis 《Geophysical Journal International》1990,102(1):231-255

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Limits on lateral density and velocity variations in the Earth's outer core   总被引：1，自引：0，他引：1  

D. J. Stevenson 《Geophysical Journal International》1987,88(1):311-319

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Interaction of a cylindrical thin‐walled pile with an inhomogeneous isotropic elastic medium          下载免费PDF全文

M. Shahmohamadi  A. Khojasteh  M. Rahimian  R. Y. S. Pak 《国际地质力学数值与分析法杂志》2018,42(15):1840-1865

This paper presents a rigorous analysis for the static interaction of a cylindrical thin‐walled pile with an inhomogeneous isotropic elastic half‐space under vertical, horizontal, and torsional forces individually applied at the top of pile. The inhomogeneity is specified with the exponential variation of shear modulus along depth of the embedding medium, and the Poisson's ratio is assumed to be constant. By means of a set of Green's functions for pile and soil medium and satisfying the compatibility conditions between the 2 interacting media, the formulation is reduced to coupled Fredholm integral equations. Using the adaptive‐gradient elements, capable of capturing the singular stress transfer at both ends of the pile, a numerical procedure is developed and utilized for evaluating the relevant integral equations and studying the inhomogeneity effect on the soil‐pile interaction responses. The analysis results have been validated for different soil‐pile modulus ratios under axial load and for a Poisson's ratio of 0.3 under lateral load. The procedure does not consider the nonlinear behavior of the soil medium or plastic yielding in the pile section, and the impact of the unreliable results for the case of high Poisson's ratio is not examined.  相似文献   

西北太平洋热带气旋生成数在不同资料集上的差异性比较   总被引：2，自引：2，他引：0  

吴胜安  孔海江  吴慧 《热带气象学报》2009,25(6):660-666

比较分析中国气象局(CMA)、美国台风联合警报中心(JTWC)和日本RSMC Tokyo台风中心(JMA)台风资料频次的年际、年代际变化和周期变化特征,结果表明,不同资料中心的热带气旋(TC)、台风(TS强度及以上的TC)生成数的气候值存在一定的差异,热带气旋生成数的差异较为明显,台风生成数的差异相对要小,CMA资料中热带气旋、台风生成数相对偏多;CMA与JTWC间热带气旋生成数年际间变化差异显著而难以忽略,其差异主要来自TD生成数的明显不同;三个中心关于台风生成数的一致性比较好,其中JMA台风资料与另外两个中心资料间的一致更好;CMA与JTWC西北太平洋热带气旋生成数的周期变化间无明显差异,但年代际间变化有明显差异,主要表现为1990年代的反位相;台风生成数资料可能在1960年代后期存在非均一性。  相似文献   

Detecting inhomogeneity in daily climate series using wavelet analysis   总被引：1，自引：0，他引：1  

严中伟 《大气科学进展》2008,25(2):157-163

A wavelet method was applied to detect inhomogeneities in daily meteorological series, data which are being increasingly applied in studies of climate extremes. The wavelet method has been applied to a few well- established long-term daily temperature series back to the 18th century, which have been ＂homogenized＂ with conventional approaches. Various types of problems remaining in the series were revealed with the wavelet method. Their influences on analyses of change in climate extremes are discussed. The results have importance for understanding issues in conventional climate data processing and for development of improved methods of homogenization in order to improve analysis of climate extremes based on daily data.  相似文献