临猗5.0级地震前后品质因子值变化特征研究     

王卫东  张永志  杜长娥 《地球科学与环境学报》2005,27(1):70-71,79

利用西安数字地震遥测台网记录的数字地震资料，采用P波初动半周期残差法求得1998年7月临猗5．0级地震前后不同路径的Q(品质因子)值变化，发现在地震发生前Q值为87～203，震后Q值为67～164，震前震中区附近出现明显的高Q值异常。结果表明，地震前的高Q值异常可以作为地震预测的一种手段。  相似文献   

The masers of E-type methanol in orion KL and SGR B2   总被引：2，自引：0，他引：2  

Q. Zeng  G. F. Lou  S. Z. Li 《Astrophysics and Space Science》1987,132(2):263-268

Using a simplified model the statistical equilibrium and radiative transfer equations of E-type-CH₃OH are solved for Orion KL and SgrB2. According to our calculation results and the observation data taken by Matsakiset al. (1980) and Morimotoet al. (1985a, b), the physical conditions of both sources are estimated. In theJ ₂-J ₁ E methanol maser region of Orion KL, the density, kinetic temperature, dust temperature, and the fractional abundance are 0.8–2×10⁶ cm^–3, 150, 30–90 K, 0.8–8×10^–6. In the 4_–1-3₀ E and 5_–1-4₀ E methanol maser region of Sgr B2 the correspondance physical conditions above are 10⁴ cm³, 45, 23 K, and 7×10^–7, respectively.  相似文献   

密度和压缩系数的散射层析成像法   总被引：1，自引：1，他引：0  

袁晓晖  王妙月 《地球物理学报》1991,34(6):753-761

本文在速度成像的基础上研究了同时对密度和压缩系数成像的散射波层析成像法.对不同散射角度的计算可以得到一系列反演图像,拟合这些图像,从而可以有效地达到对密度和压缩系数（或速度）成像的目的.与单纯的速度成像相比,增加了反演的难度.首先是对资料的方位性要求增加;其次是对资料的利用率下降.即便如此,从对较少量的炮点和检波点资料的数值计算来看,仍取得了满意的成像结果.我们对组成字母“A”的散射体结构进行了成像计算,结果能够同时再现密度和压缩系数,成像清晰,表明了方法的可行性,并能应用于复杂结构的成像问题.  相似文献   

造山带中富集型上地幔的成因——以萨尔托海蛇绿岩块为例   总被引：1，自引：0，他引：1  

郝梓国  王希斌  鲍佩声 《地球学报》1991,12(1):159-166

发育于造山带中的蛇绿岩,其剖面下部的地幔橄榄岩部分是造山带地区富集型上地幔的直接标本。其地球化学特点是:主要元素Al_2O_3、TiO_2、CaO、Na_2O、K_2O强烈亏损,而REE,痕量元素和87Sr/86Sr则强烈富集;同时,143Nd/144Nd<0.511836,亦表明它们属于一个富集型的源区。 形成富集型上地幔的主要机制是地幔交代作用,富含不相容元素的低熔岩浆和富Ca-LREE流体与已亏损的地幔橄榄岩发生脉状交代和渗透交代反应,从而造成上地幔中不相容元素的富集。造山带富集型上地幔形成的构造环境是:洋壳从扩张脊向两侧运移并最终拼入造山带这段时间内。富集型上地幔不但存在于大陆区,而且亦存在于造山带地区,它可能是一种全球性的地球内部的化学作用。  相似文献   

Cosmological implications of BL Lac objects     

G. Z. Xie  F. K. Liu  Y. Y. Zhu  J. H. Fan  R. W. Lu 《Astrophysics and Space Science》1991,179(2):321-329

It has become clear in recent years that relativistic beaming is a good explanation for the BL Lac phenomenon. Of studies based on the relativistic beaming model of BL Lac objects, we note that the orientation of jet's axis to the line-of-sight is very small and, therefore, the observed flux emitted from a rapidly moving source is orders of magnitude higher than the flux in its rest-frame:F _obs = ^{3 +} F _intr, where is the bulk relativistic Doppler factor. Then the observed apparent magnitudem _v must be corrected for this effect. For our 39 samples, the corrected apparent magnitudem _v ^corr and logZ have a good correlation.  相似文献   

Observations of interstellar HOCO+: abundance enhancements toward the galactic center     

Minh YC  Irvine WM  Ziurys LM 《The Astrophysical journal》1988,334(1):175-181

A survey of the 4(04)-3(03) and 1(01)-0(00) transitions of HOCO+ has been made toward several molecular clouds. The HOCO+ molecule was not observed in any sources except Sgr B2 and Sgr A. The 5(05)-4(04) and 4(14)-3(13) transitions were also detected toward Sgr B2. The results indicate that gas phase CO2 is not a major carbon reservoir in typical molecular clouds. In Sgr B2, the HOCO+ antenna temperature exhibits a peak approximately 2' north of the Sgr B2 central position (Sgr B2[M]) and the 4(04)-3(03) line emission is extended over a approximately 10' x 10' region. The column density of HOCO+ at the northern peak in Sgr B2 is approximately 3 x 10(14) cm-2, and the fractional abundance relative to H2 > or = 3 x 10(-10), which is about 2 orders of magnitude greater than recent predictions of quiescent cloud ion-molecule chemistry.  相似文献   

A high-resolution bragg spectrometer for the observation of the hot interstellar medium X-ray emission     

J. Y. Deschamps  R. Rocchia  A. Tarrius 《Astrophysics and Space Science》1986,121(2):321-332

We present a high-resolution Bragg spectrometer designed for the observation of the soft X-ray cosmic diffuse background. The instrument concept is derived from the de Broglie geometry for the study of extended sources. It consists in a mosaïc of spherical TlAP crystals associated with position sensitive detectors located on the focussing surface. The spectral resolution and its variation with the field of view is estimated by Monte-Carlo simulations for different X-ray energies chosen among the most intense lines emitted by an astrophysical plasma in the temperature range 1–4×10⁶K. The estimated sensitivity and the simulations of actual space observations show that the instrument is capable to separate the strongest lines emitted by the most abundant ions (OVII,OVIII, FeXVII, NeIX, etc.) and to map the whole sky during a six month mission.  相似文献   

Emission curve of growth for Feii in chromospheric limb spectra     

Y. Hanaoka  I. Tsuda  K. Sadakane  M. Kanno 《Solar physics》1986,106(1):87-93

The 270 chromospheric emission lines of Feii ranging between 2000 and 3200 Å observed by Skylab at a height of 4 (2900 km) above the limb of the quiet Sun are analyzed by the emission curve of growth method, using newly calculated gf-values. It is derived that the excitation temperature is 7.2 × 10³ K and that the turbulent velocity is consistent with the previous results that the microturbulent velocity is lower than 10 km s^–1 in the cool (<10⁴ K) region of the chromosphere.Contributions from the Kwasan and Hida Observatories, University of Kyoto, No. 270.  相似文献   

Use of the population potential model for predicting the growth of cities in a region (with reference to Moscow Oblast)     

Molodikova IN  Khanin SY 《Soviet geography》1986,27(2):75-83

"A modification of the population potential model is used to analyze the structure of the potential of population for cities of the Moscow region, to develop a relationship between population potential and city size, and to use this procedure to forecast future population change in Moscow Oblast cities." Cities in the region with a population of 50,000 or more at the censuses of 1959, 1970, and 1979 are included.  相似文献   

Optical observations of the interstellar absorption lines towards the M8 Nebula     

Barry Y. Welsh 《Astrophysics and Space Science》1983,90(2):437-444

High resolution optical observations (FWHM ～ 10–13 km s^?1) of the I-S gas towards the early-type stars HD 164 794, HD 164816, and HD 165052 in the M8 Nebula are presented. A high velocity componentV _LSR=?26 km s^?1 has been detected in all 3 stars' spectra. A line profile fitting analysis has been carried out on the observed Caii and Nai absorption lines to determine cloud component column densities and to subsequently determine the physical and chemical conditions of the associated I-S gas.  相似文献