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971.
青藏高原对四川盆地的挤压作用导致了龙门山断裂带的形成及其山脉的隆起。本文以龙门山附近区域板块运动以及深部岩体力学特性为背景,采用FLAC3D软件模拟再现了时间跨度为700万年的龙门山区域构造系统演化过程。研究结果表明:在板块运动作用下,F1、F2和F3断层依次形成,贯通的断层对地表的抬升具有较强的控制作用,当断层贯通于地表后,龙门山及其以西的川西高原持续隆起,平均抬升速率约为1.38mm/yr,而龙门山断裂带以东的川西坳陷只有较小的抬升量,从而导致川西高原抬升8996 m,致使该区域产生6000m左右的落差,模拟的地形特征与目前的龙门山地形地貌基本相似。依据模拟结果与实测资料,绘制了龙门山断裂带形成及其附近区域地形地貌的演化过程图,呈现了板块挤压、断层塑性位错、地表侵蚀和沉积作用等因素共同作用对地形地貌的塑造过程。 相似文献
972.
973.
Lian-shu Cui Ju Hu Guo-ping Ji Xiang-bin Ni You-ran Huang Cheng Fang 《Chinese Astronomy and Astrophysics》1985,9(1):49-53
Using the solar tower telescope of Nanjing University, we observed the two large loop prominence groups of 1982 Dec. 20 and 1983 Feb. 9. Hα photographs and spectra around the Hα and H and K lines were obtained simultaneously. From these data, we derived a line of sight velocity distribution, which agrees perfectly with the distribution for matter falling freely without viscosity. From the widths of the Hα and the K lines, we found the loop material to have a uniform kinetic temperature and a turbulent velocity that increases with height. From the central intensities of the lines we derived a density of n(H) ? 1.3 ? 2.6 × 1010cm?3. A possible mechanism of the formation of loop prominence groups and their relation with flares are discussed. 相似文献
974.
975.
Jin Sheng-zhen Li Xiao-cong Ji Hui-rong Zhao Bing Wang Shu-lan Yan Yuan-yi Zhao Ren-yang 《Chinese Astronomy and Astrophysics》1993,17(4):406-412
We briefly describe the polarization state of the spike groups and fast fine structures superimposed on the 47GB microwave burst of 1991 May 16. At two frequencies 100 MHz apart, namely, 2645 and 2545 MHz, the polarization showed rapid reversals on short time scales of the order of 50 100ms. We think this is probably related to fluctuations on both short time and small spatial scales, in the plasma density and magnetic field of the emission region. Thése oscillations cause the plasma and cyclotron frequency ratio to vary around the value of
, thus making the electron cyclotron maser instability growth rate to be dominated alternately by the X mode and the O mode and the polarization state to switch from one sign to the other. 相似文献
976.
We assume that the physical conditions above an active solar region vary continuously from the centers of sunspots to the adjacent quiet region and try to take into account the influence of the magnetic field. Thus we calculate the three-dimensional distribution of the electron temperature and density based on the radio spectrum of active region No. 75 obtained from the solar eclipse observation of 16 February, 1980. If we assume a potential field, we calculated the magnetic field above the active region in terms of the solar photospheric magnetic field.Using the electron temperature, density, and the magnetic field as described above, and assuming the slowly varying radiation mechanism to consist of bremsstrahlung and gyro-resonance radiation, we obtained the flux density spectrum and the brightness temperature spectrum. The calculated results are essentially consistent with the observations. 相似文献
977.
本工作是为今后在1.2米望远镜上利用商用CCD配备录像机进行人卫快速精密定位观测所做的初步试验,其目的是在实验室里模拟检测商用CCD配备录像机后对星像的绝对及相对定位精度。通过使用不同图像板及录像带在不同幅度的CCD视频信号情况下的分组试验,得到了满足人卫观测的结果,CCD对绝对位置及相对位置的定位误差均小于±0.5个象元。本文还对误差产生的原因进行了初步分析。 相似文献
978.
Sixty-one blue spectrograms of TX UMa were obtained in the years 1969–1970, mainly in phases close to the primary minimum of the eclipsing system. The radial velocity curve displays clear rotational effect from which much higher than synchronous rotational velocity of the blue (B8V) component has been formally derived. However, this discrepancy is probably due to the presence of the tenous accretion disk around the primary. The disk is apparently fed by the intermittent mass transfer as indicated by the occasional changes of orbital period of the system. From all available radial velocity data an improved set of spectroscopic orbital elements is derived. The behaviour of the spectral lines in and out of the primary minimum is compared. Metallic lines of the cold (F7IV) secondary component are clearly seen exclusively in phases 0.988 to 0.012.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain. 相似文献
979.
980.
Meng Fanchao Li Mingcai Cao Jingfu Li Ji Xiong Mingming Feng Xiaomei Ren Guoyu 《Theoretical and Applied Climatology》2018,133(1-2):521-530
Theoretical and Applied Climatology - Climate plays an important role in heating energy consumption owing to the direct relationship between space heating and changes in meteorological conditions.... 相似文献