The Spin-X wide-field X-ray monitor of the Spectrum-X-Gamma astrophysical observatory

The Spin-X wide-field X-ray monitor of the Spectrum-X-Gamma astrophysical observatory, which is based on the principle of a coded-aperture telescope, is designed to detect and localize cosmic gammaray-burst (GRB) sources; to survey large areas of the sky in search of new transients; and to carry out long-term observations of bright Galactic sources, including X-ray bursters. The monitor consists of two noncoaxial identical modules, Spin-X1 and Spin-X2, which together cover 6.8% of the sky. The high-apogee, four-day orbit of the Spectrum-XG satellite allows the instrument to be in observing mode more than 50% of the time. Having simulated the rate of GRB detection by Spin-X, we show that extrapolating BATSE 50–300-keV average data on the number of GRBs, their duration, and their mean energy spectrum to the X-ray energy band leads to disagreement with the observed detection rate of GRBs in the X-ray band. The number of GRBs that can be detected and localized with an accuracy r≤3′ (3σ) (the error-circle radius) by Spin-X is estimated to be ten bursts per year. We present data on the Spin-X sensitivity achievable during long-term observations of persistent and transient sources and on its sensitivity to X-ray bursts from Galactic sources in the 2–30-keV energy band.     

Oscillation structure of gamma-ray bursts and their possible origin

It is hypothesized that thermonuclear burning of the matter from the envelope of a massive compact star accreting onto a hot neutron star produced by spherically symmetric collapse of a stellar iron core can proceed in oscillation mode (much as is the case during thermal explosions of carbon-oxygen cores in lower mass stars). Local density oscillations near the neutron-star surface can generate shock waves; in these shocks, the electron-positron plasma is stratified from the remaining matter, and shells of an expanding relativistic fireball with an oscillation time scale in cosmological gamma-ray bursts (GRBs) of ～10^?2 s are formed. It is pointed out that the GRB progenitors can be nonrotating massive Wolf-Rayet (WR) stars whose collapse, according to observational data, can proceed without any substantial envelope ejection.     

复杂金属矿体地震波正演模拟研究-以庐枞罗河-泥河-大包庄矿床为例

地震勘探在金属矿勘查中发挥越来越重要的作用,但复杂的介质结构和矿体形态通常使金属矿地震解释异常困难,为深入研究复杂金属矿体的地震波场特征,有效开展金属矿地震解释,本文以庐枞矿集区的罗河、泥河和大包庄矿床为例,在详细开展物性测量和地质与地球物理建模的基础上,对均匀介质复杂矿体模型、简化矿体模型和随机介质简化矿体模型进行了...     

三维正交各向异性孔隙介质震电波场数值模拟研究

各向异性等介质物性参数会对震电波场的传播产生影响.为了定量研究介质物性参数对震电波场传播的影响, 本文首先研究了三维正交各向异性介质的震电耦合方程, 然后采用时域有限差分方法模拟了爆炸源在该介质中的震电响应.在数值模拟中, 首先计算地震波场, 然后把地震波场作为输入来计算伴随电场.为了验证数值算法的精度, 我们将数值结果与从Pride方程获得的解析解进行了对比, 结果表明数值解可以很好地近似解析解.我们设计了几种各向异性模型, 分析了介质物性参数对震电波场的影响, 结果表明爆炸源在各向异性孔隙介质中会产生四种地震波, 分别是快慢纵波和两个可分离的横波.产生的地震波都会在均匀各向异性孔隙介质中产生伴随电场.弯曲度对慢纵波的传播有影响, 当弯曲度为各向异性时, 慢纵波的波场快照为椭圆形, 当弯曲度为各向同性时, 慢纵波的波场快照为圆形.

     

The Maastrichtian-Danian in the SW Zagros Fold-Thrust Belt (S. Iran): An Integration of Planktonic Foraminiferal Biostratigraphy and Gamma-Ray Spectrometry

In this study, the Maastrichtian-Danian boundary was measured and sampled in two stratigraphic sections, the north and south flanks of the Dehnow anticline in Coastal Fars, Southern Iran. This boundary was also investigated in the drilled exploratory well-1 in the same region. The lithology of the Maastrichtian-Danian deposits consists of glauconitic, phosphatic argillaceous limestones and marlstones. 30 genera and 77 species of planktonic foraminifera have been determined. The recognized biozon...     

塔里木盆地中—下寒武统自然伽马测井曲线周期及其在沉积层序划分中的意义

盆地的沉积充填能够反映出周期性地质过程和天文过程。塔里木盆地中下寒武统地层保存完整,有较完整的自然伽马（GR）曲线。利用环满加尔坳陷的13口钻井的自然伽马（GR）曲线,施行经验模态分解,得到0.3 Ma、2 Ma和11 Ma的周期。0.3 Ma的峰值对应地球轨道偏心率的40万年周期性变化,2 Ma周期对应冰川型海平面变化周期,11 Ma周期对应太阳能量变化周期或星际云团相遇周期。这些周期补充和校准了先前得到的地质或天文周期,并能帮助理解古气候变化周期和高频层序地层。     

土壤中铀系不平衡对地面伽马能谱测量的影响

对采自云南省个旧地区的100件土壤样品进行室内多道伽马能谱分析后发现,该地区土壤的铀镭平衡系数为0.65,表现出贫镭偏铀的特征.铀镭的不平衡导致地面或航空伽马能谱测量中铀道数据与实际情况有很大的误差,因此需要作适当地处理加以修正.     

一种反演地幔横向密度差异的方法

重力位球谐系数及板块运动速度是两种独立的地球物理观测资料,但二者同时又是地幔内横向密度差异及与之相联系的地幔流动的结果,从而,中长波重力异常与板块运动的观测提供了探索地幔横向非均匀的一条途径。本文根据适合于低雷诺流动的最小粘滞损耗原理,利用张量场及矢量场的标量分解与传播子解的数学方法,将观测的重力位球谐系数和板块运动速度作为约束条件,发展了一种反演地幔横向密度差异的方法。     

中期数值天气预报的误差订正方法探讨

本文利用一个全球谱模式（T63L9）和1994年4个时段个例的全球客观分析资料探讨了中期数值天气预报的误差订正方法。个例分析的结果表明,采用定常误差订正和时空平滑误差订正方法,误差订正效果显著,可考虑在业务系统中采用。     

The point-spread function for airborne radiometry

Pointwise division in the Fourier domain can be used to deconvolve the effects of aircraft altitude upon gridded, two-dimensional, radiometric count data. The appropriate divisor function, expressed as a triple integral by Gunn, is developed as a convergent series suitable for its numerical evaluation. For various flying heights, graphs display in cross-section the corresponding, radially symmetric, divisor function.