Geochemical analyses of geological layers and groundwater flows

X-ray fluorescent spectroscope analysis easily finds ratios of geochemical elements in soil. Applying the method of ratio matching to measured ratios, the classification of geological layers, and the flow directions of groundwater can be determined. This method is applied to three hill slopes in Japan and the results are in good agreement with the observations and measurements of soil cores obtained by drilling. The classification of geological layers is found to be quantitatively connected with the rates of organic matter in soil cores. Received: 5 February 1999 · Accepted: 7 September 1999     

Multi-Wavelength Synchrotron Radiation XRF Determination of U and Th in Sedimentary Cores from Lake Baikal

A new technique for the determination of uranium and thorium in lacustrine sediments is based on non-destructive synchrotron radiation X-ray fluorescence analysis (SR-XRF) of sediment samples using monochromatic beams of different energies as excitation sources, with the recording and subsequent iterative processing of the X-ray fluorescence spectra. The technique has a multielement capability and enables fast, simultaneous analysis of a few tens of elements. The proposed SR-XRF technique was tested against INAA and ICP-MS methods and showed a number of advantages with a generally good correlation of results by the three methods. Uranium and Th profiles have been measured at a time resolution of 2 kyr in a drill core (BDP-96) from Lake Baikal bottom sediments deposited between 780 and 40 kyr B P. During this time span, peaks in the U and U/Th concentration marked warm climates. Oscillations of U and U/Th in Baikal bottom sediments during the Brunhes chron reflect climate-induced global change in the volume of polar ice, controlled by long-term cyclicity of the Earths orbital parameters. The response of these warm periods is similar to that observed earlier in shorter cores that span the two last interglacials (220-0 kyr BP).     

X荧光测量在区域化探异常检查中的应用

介绍了Ｘ荧光测量仪的原理和使用范围,从多年的找矿实践中总结其在四川省地勘局的区域化异常检查中的诸方面的重要作用,并指出其优缺点。     

微焦点X射线计算机层析(CMT)及其在石油研究领域的应用

工业微焦点ＣＴ的Ｘ射线源焦点尺寸小于５微米,成象分辨率明显优于常规焦点ＣＴ。在石油勘探开发研究中;微焦点ＣＴ在许多技术领域进行了应用,取得了崭新的成果：（１）确定岩心的基本物理参数—计算和描绘密度、孔隙度、流体饱和度分布;（２）描述岩心的微观特征—直观描述岩石内部孔隙结构和流体分布特征;（３）特殊油藏岩心分析评价—观察碳酸岩、火成岩等内部一些常规技术无法获得的特征;（４）岩心驱替和提高采收率分析—重建油水在岩心内部的宏观分布状态;（５）其他方面的应用—岩心筛选、地层伤害评价、岩石力学评价等。     

空洞性肺结核的CT诊断

目的：分析空洞性肺结核的ＣＴ表现和特征,探讨ＣＴ诊断该病的可靠性。材料与方法：２１例空洞性肺结构病人均做胸部ＣＴ和胸片检查,分析ＣＴ所见并与病理、胸片对照,１０例经组织病理学证实。１１例痰检和临床证实。结果：（１）肺上叶尖后段及下叶背段为空洞性肺结核的好发部位;（２）空洞呈圆形或椭圆形,空洞外壁较光整,空洞壁常有钙化;（３）空洞所属支气管壁不规则增厚;（４）临近空洞胸膜局限性增厚;（５）空洞以外肺     

成层非均匀地壳中应变能密度场时空分布的动态模拟研究.

通过对坚固体孕震模型应变能密度场动态变化的模拟研究,对地震孕育过程、初始破裂、始裂条件和破裂的传播方向等问题取得了进一步的认识．结果表明:孕震过程初期,软弱体部位应变能密度水平很高,但在孕震过程后期,其应变能密度增量水平变小,坚固体及其与直立断层交汇部位的应变能密度增量迅速变大,成为应变能密度增量最大的地方,从而使弹性模量比较大的坚固体与直立断层交汇处成为最先破裂发震的部位．破裂在直立断层端部的坚固体内沿着与断层成近于直交的方向传播,这样,理论上确定的破裂方向与实际计算的破裂方向得到了很好的统一．      

北京崎峰茶金矿床X光岩石组构分析

岩石组构是指组成岩石的矿物在岩石中分布的各向异性,Ｘ光岩组分析就是运用Ｘ光衍射技术测定岩石结构要素－岩石中矿物分布的规律性。通过对北京崎峰茶金矿区含矿韧性－韧脆性变形岩石为Ｘ光岩组分析,认为该区岩石变形比较明显,石英变形机制是以中低温底面或近底面滑移为特征,而作为斜长角闪质岩石和长英质岩石的退变质矿物绿泥石和绢云母等片状矿物则平行变形面理定向排列。从岩石组构特点结合宏观构造分析可以推断,该区属于中     

Optical spectra of four objects identified with variable radio sources

We obtained optical spectra of four objects identified with variable radio sources. Three objects (0029+0554, 0400+0550, 2245+0500) were found to be quasars with redshifts of 1.314, 0.761, and 1.091. One object (2349+0534) has a continuum spectrum characteristic of BL Lac objects. We analyze spectra of the radio sources in the range 0.97–21.7 GHz for the epoch 1997 and in the range 3.9–11.1 GHz for the epoch 1990, as well as the pattern of variability of their flux densities on time scales of 1.5 and 7 years.     

X-ray variability of the pulsar Vela X-1 as observed with ART-P/Granat

Observations of the X-ray pulsar Vela X-1 with the ART-P telescope onboard the Granat Observatory are presented. Variability on a time scale of several thousand seconds was detected; intensity variations are shown to be accompanied by changes in the source’s spectrum. The hardness was also found to be highly variable on a scale of one pulsation period. The source’s spectrum exhibits an absorption feature at energy ～7 keV, which is apparently attributable to cyclotron scattering/absorption in the neutron-star magnetic field. Weak persistent emission was detected during an X-ray eclipse, which probably resulted from the scattering of pulsar emission in the stellar wind from an optical star.     

Energy release on the surface of a rapidly rotating neutron star during disk accretion: A thermodynamic approach

The total energy E of a star as a function of its angular momentum J and mass M in the Newtonian theory, E=E(J, M) [in general relativity, the gravitational mass of a star as a function of its angular momentum J and rest mass m, M=M(J, m)], is used to determine the remaining parameters (angular velocity, chemical potential, etc.) in the case of rigid rotation. Expressions are derived for the energy release during accretion onto a cool (with constant entropy), rapidly rotating neutron star (NS) in the Newtonian theory and in general relativity. A separate analysis is performed for the cases where the NS equatorial radius is larger and smaller than the radius of the marginally stable orbit in the disk plane. An approximate formula is proposed for the NS equatorial radius for an arbitrary equation of state, which matches the exact equation of state at J=0.