The radio frequency dielectric properties of the stratified UG1–UG2 geological unit in the Bushveld Complex

A new measurement technique enables the complex dielectric properties of the geological strata comprising the UG1–UG2 (Upper Group 1–Upper Group 2) unit of the Bushveld Complex in South Africa to be determined with unprecedented detail at radio frequencies (RF). Results of non-destructive laboratory measurements of representative diamond drill core samples from the UG1–UG2 unit are presented at 25 MHz. These data establish that the UG1 and UG2 chromitite layers are embedded in rock strata (norite, pyroxenite and anorthosite) which are translucent in the HF spectral band, whereas the chromitite layers themselves exhibit significant velocity contrast, making them good radar reflectors. The data presented here is useful for calibration of the radar system, and for predicting the range and resolution performance of borehole radars operating in both the hanging and footwalls of the economically important platiniferous UG2 reef.     

A non‐baseline algorithm for damage locating in flexural structures using dynamic distributed macro‐strain responses

The concept of distributed strain‐sensing techniques has been proposed in our recent research, which was dedicated to utilizing the strain distributions throughout the full or partial areas of structures to detect arbitrary and unforeseen damage. An algorithm not requiring a detailed analytical model is presented for damage locating in flexural structures through the direct use of dynamic responses recorded by distributed long‐gauge strain sensors. The modal macro‐strain vector (MMSV), which has been proven to have a mapping relation with displacement mode shape, can be extracted directly from macro‐strain time‐series data, from which a damage evaluating index can be derived and used as an indicator for locating damage. Numerical examples are simulated to verify the sensitivity and effectiveness of the index in different cases. Furthermore, experimental investigations on a cantilevered beam with various long‐gauge fibre optic sensors placements are carried out to examine the feasibility and applicability of the proposed method. Copyright © 2007 John Wiley & Sons, Ltd.     

柴东侏罗系源岩生油组分荧光特征与生烃意义

通过荧光特征研究了柴达木盆地东部侏罗系源岩生油组分,指出了不同生油组分对生烃的贡献、意义及其热演化特征。侏罗系源岩有暗色泥岩、油页岩、煤和炭质泥岩四种类型,主要生油组分为壳质组和矿物—沥青基质,不同生油组分荧光特征的差异又是生烃潜力大小、热演化程度和降解情况的综合反映。     

银矿床基本物性特征及银矿物探成功经验

通过研究国内外各类银矿床地质资料中银矿石的共生矿物组成，得出了各类银矿床的基本物性特征，为合理选择银矿物探的有效方法提供了依据；引述和分析了银矿物探取得显著效果的若干实例，说明合理的综合找矿方法在银矿找矿中的巨大潜力有待发挥。     

Long-term climato-limnological cycles found in a 3.5-million-year continental record

Analysis of physical properties in long sediment cores (BDP96) from Academician Ridge in Lake Baikal indicates that major climato-limnological changes during the past 3.5 Myr occurred at about 2.5–2.8, 1.7–1.9, and 0.9–1.2 Ma, which were close to times of major geomagnetic polarity reversals (Matuyama/Gauss, Olduvai, Jaramillo + Matuyama/Brunhes). The principal climato-limnological oscillation has a long-term period of nearly 1,000 kyr, which corresponds to the periodicity of fluctuation in solar insolation. It also seems to be related to geomagnetic field intensity. Other long-term period of 400 kyr corresponds to Milankovitch parameters of eccentricity. These results suggest that changes in solar insolation were closely related to long-term environmental variations in the deep continental interior.     

姚桥矿地下水化学特征及在矿井水源判别中的意义

姚桥矿地下水系统包含四个子系统：新生界孔隙含水层组，煤系砂岩裂隙含水层组，太原群石灰岩溶隙含水层组及奥陶系灰岩岩溶含水层组。通过对这四个子系统水文地球化学特征的系统研究，提出了各子系统所特有的水质模型，并确定出能作为矿井水源判别依据的水溶组分，为矿井防治水提供水化学特征依据。     

直流电法在探测老窑采空区的应用

在各种工程地质、环境地质中、对地下采空区的探测是地球物理勘探的一项重要内容。文章从物性参数研究、技术方法择方面入手，探讨了直流电法探测老窑采空区的可行性，并以实例介绍了解决该问题所取得的经验。     

油、水、干层的地球化学识别

本文介绍一种判断油、水、干层的地球化学方法，根据储层样品中有机抽提的的含量和组成特征，结合油层物性，地层测试和试油资料编制织识别油、水，干层的图版，提出判别油、水、干层的地质／地球化学指标，确定油层的地球化学参数的下限，并运用此方法对松辽盆地新站油田主要油层分布段的油、水、干层进行判别。根据试油资料验证表明，地球化学判断结果比传统的地质录井及地球物理测井资料判断结果更符合实际情况。     

线性石蜡基钻井液的试验研究

近期在室内研制成功了新型的第二代合成基钻井液的代表——线性石蜡基钻井液。首先从大量的试验结果中优选出了线性石蜡基钻井液配方 ,在此基础上 ,对线性石蜡基钻井液的性能进行了系统的评价。研究结果表明 ,优选出的线性石蜡基钻井液配方简单。和柴油基钻井液相比 ,线性石蜡基钻井液具有优良的热稳定性、页岩抑制性、润滑性能和储层保护性能 ,可用作深井复杂地层的钻井液     

Thermoelastic model of minerals: application to Al2O3

 A thermoelastic model for calculating the high-pressure and high-temperature properties of isotropic solids is presented by extending the formalism by Thomsen and combining the resulting one with the Vinet model for static lattice and the Debye model for lattice vibration. Applying it to polycrystalline corundum, we have shown that the calculated values of entropy and heat capacity at constant pressure are in agreement with literature values to 2325 K at zero pressure and that the calculated values of thermal expansivity agree reasonably with experimental data to 1100 K at zero pressure. The model reproduces experimental data of sound velocities v _p and v _s of compressional and shear waves to 1825 K at zero pressure and those to 62 GPa at room temperature, and it reproduces also experimental shock-wave equation of state to 150 GPa. The velocity correlation (∂ln v _s /∂ln v _p ) _S was found to have weak pressure and temperature dependences and the results under lower mantle conditions are compared with those of magnesian and calcium silicate perovskites and magnesiowüstite, and the PREM values of the Earth's lower mantle. Received: 12 February 2000 / Accepted: 15 July 2000