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71.
Songliao Basin is filled predominantly with continental facies sediments including alluvial fan, fluvial plain, fan delta , lacustrine delta, shore ?shallow lacustrine, beach salty flat, semi - deep to deep lacustrine, subaqueous gravity flow, lacustrine swamp and pyroclastic sediments. However, some event units were formed during lake - marine linking periods of the Mid - Cretaceous in the basin, which include black shales with high values for salinity ( Sr/Ba) , alkalinity (Ca Mg)/ (Si Al) , reducibility ( Ni Zn)/Ga and sulfide sulfur as well as heavy isotopes. The Breitenholz ?section to be represen-ted for facies comparison with the Cretaceous evaporitic series in Northeast China is localized in Southwest Germany. Stratig-raphically it belongs to the Crabfeld Formation of Keuper of the Germanic Triassic corresponding to Ladinian - Camian of the international reference scale, and is generally called Lower Gipskeuper. The Germanic Triassic was deposited in the epiconti-nental(cratonic) central Euro 相似文献
72.
The determination of boundary points and their correlation are prerequisites for defining the PrecambrianCambrian boundary and the intercontinental correlation. A large number of good Precambrian-Cambrian boundary sections in South Asia not only possess the conditions for selection of a boundary stratotype, but also provide the basis for the long-distance correlation of those boundary sections.Through a detailed study of the latest data obtained from the typical sections in South China, the Lesser Himalaya Mountains and the Alborz Mountains. the locations of boundary points have been defined, and a correlation scheme is proposed, which contributes to the solution of the problem of worldwide correlation of boundary sections. 相似文献
73.
Dong-Mei Qin Ping Guo Zhan-Yi Hu Yong-Heng ZhaoNational Laboratory of Pattern Recognition Laboratory Institute of Automation Chinese Academy of Sciences Beijing dmqin@nlpr.ia.ac.cnDepartment of Computer Sciences Beijing Normal University Beijing National Astronomical Observatories Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2003,3(3)
For LAMOST, the largest sky survey program in China, the solution of the problem of automatic discrimination of stars from galaxies by spectra has shown that the results of the PSF test can be significantly refined. However, the problem is made worse when the redshifts of galaxies are not available. We present a new automatic method of star/(normal) galaxy separation, which is based on Statistical Mixture Modeling with Radial Basis Function Neural Networks (SMM-RBFNN). This work is a continuation of our previous one, where active and non-active celestial objects were successfully segregated. By combining the method in this paper and the previous one, stars can now be effectively separated from galaxies and AGNs by their spectra-a major goal of LAMOST, and an indispensable step in any automatic spectrum classification system. In our work, the training set includes standard stellar spectra from Jacoby's spectrum library and simulated galaxy spectra of EO, SO, Sa, Sb types with redshift ranging from 0 to 1 相似文献
74.
根据Marshall空间飞行中心(MSFC)太阳天文台的矢量磁场测量和云南天文台的黑子细节照相资料,作者们详细研究了1986年2月初太阳大活动区(AR4711)的形态和演化。主要结论如下: i)几乎在活动区中每处地方,相距五小时观测到横向磁场排列方向和黑子半影纤维形态之间存在良好的相似性。 ii)利用文[4]的方法,推断了本活动区强的垂直电流源和强的水平电流渠道。 iii)与1972年8月初著名的太阳活动区(McMath 11976)相类似,沿老活动区的中性线的新浮磁通管的两足点(偶极黑子)的分离运动导致了一个密集四极磁结构的形成。 iv)新浮磁通管似乎是本活动区最强的电流系统。 上述结论将为进一步研究本区电流/磁场环系的演化及其与耀斑活动的关系提供一个基础数据。 相似文献
75.
O.W.TU 《地理学报(英文版)》1935,(1)
The object of this paper is to show that the general poverty of the Chinese people is not caused by over-population, but by the primitive methods of production, the existing system of exploitation, the political chaos and the political and 相似文献
76.
In our previous work, we searched for superflares on different types of stars while focusing on G-type dwarfs using entire Kepler data to study statistical properties of the occurrence rate of superflares. Using these new data, as a byproduct, we found 14 cases of superflare detection on 13 slowly rotating Sun-like stars with rotation periods of24.5–44 days. This result supports the earlier conclusion by others that the Sun may possibly undergo a surprise superflare. Moreover, we found 12 and se... 相似文献
77.
GEOTAIL卫星于1994年1月15日亚暴期间,在深磁尾(x=96RE)观测到多重等离子体团及与之相对应的高能离子爆,作者以宁静磁尾平衡位形为初态,考虑介质的可压缩性,数值研究亚暴期间磁尾动力学过程.计算结果展现了等离子体团间歇性形成及其运动发展过程.体现了强亚暴事件中储存于碰尾的能量,通过多重等离子体团的排放而逐渐释放的进程.数值结果还表明:持续施加于边界上的晨昏电场及由此引发的驱动重联是导致等离子体团准周期形成的主要因素.此外,作者还考察尾瓣内任一点磁场强度及其分量随时间的演化,它与行进压缩区(TCRs)的观测特征基本相符. 相似文献
78.
喀斯特城市植被覆盖度时空变化对地表温度的影响 总被引:3,自引:0,他引:3
随着桂林喀斯特城市的快速扩展、地表植被覆盖度的变化,城市热岛现象越来越明显。以桂林1989-2006年5景TM/ETM遥感图像为数据源,利用遥感归一化植被指数反演植被覆盖度Pv,利用Qin单窗算法反演地表温度ts,分析Pv空间和时间变化对ts的影响。结果表明,在空间上ts随Pv的提高而降低,呈明显负相关关系。在时间上Pv<0.2面积比例逐年增加,1989年7.8%、1991年15.2%、2000年20.7%、2005年21.1%、2006年22.7%;而Pv≥0.7面积比例逐年减少,1989年49.2%、1991年27.4%、2000年27%、2005年16.5%、2006年11.1%。其导致地表温度高于茂密林地表面温度的比率z>20%的高温像元比例逐年上升;而z≤10%的低温像元比例逐年下降,1989年28.9%、1991年25.4%、2000年23.7%、2005年22.2%、2006年20.4%。植被覆盖的喀斯特山峰呈现显著的凉岛现象,从而调节喀斯特城市气候环境。 相似文献
79.
I INTRODUCTIONWetland has very important effect on retainingwater and against drought, regUlating climate, controlling soil erosion and so on ac. Today men often attachimportance to economic effect of wetland reclamation,but neglect and destroy other functions and effectswhich result in blind wetland development, a lot ofwetland degeneration. The area of freshwater wetland inthe 1950s was 134 x 10'ha, but in the 1970s 70% hadchanged into farmland (MITSCH, 1993). The area ofwetland in d… 相似文献
80.
Received date: -- Revised date: -- Foundation item: Under the auspices of the National Natural Science Foundation of China 《地理学报(英文版)》2000,(3)
1 Introduction1.1 Introduction to Liaocheng PrefectureLiaocheng
Prefecture lies in northwest of Shandong Province and slightly north to the center of the Huang-Huai-Hai Plain with latitudes between 35(47'N and 37(02'N and longitudes between 115(16'E and 116(32'E. Administratively, it consists of two cities (Liaocheng and Linqing) and six counties (Yanggu, Shenxian, Chiping, Dong'e, Guanxian and Gaotang). It covers a total area of 8590 km2 with a maximum distance of 114 km from eas… 相似文献