西部煤炭资源调查评价中遥感技术的应用

通过西部煤炭资源勘查对遥感技术的需求以及煤田地质体的可解译性、遥感技术的实际应用效果分析,论述了西部煤炭资源调查评价中遥感技术的重要作用,提出了今后遥感技术的应用建议.     

煤田勘查超千米深孔快速钻进技术探讨

针对目前国内煤田勘查主要机具及工艺技术方法存在的主要问题,结合煤田勘查地层地质条件和超千米深孔施工要求,研制了液压立轴式HTJ-2000型钻机和新型绳索取心钻具,并就配套设备选型、钻进工艺、钻进参数、泥浆指标及应用效果进行了阐述.该项技术的应用,已明显提高了钻效,使钻孔深度达到1 350m.     

GPS RTK技术及其在管线勘控中的应用

针对GPS RTK技术应用中的工作条件、数据链传输、误差特性及质量控制等问题,结合管线勘控测量的作业特点,提出了提高RTK作业精度若干方法.     

海底可视技术在天然气水合物勘查中的应用

海底可视技术是一种可以直观地对海底地形地貌、表层沉积物类型、生物群落等进行实时观察的调查手段。本文介绍了海底摄像、电视抓斗、深拖系统和ROV四种海底可视技术，并对海底可视技术在南海北部陆坡天然气水合物勘查中的应用进行阐述。利用海底可视技术，在南海北部陆坡发现了天然气水合物气体“冷泉”喷溢形成的自生碳酸盐岩和活动于天然气水合物冷喷溢口或渗流口周围的菌席、双壳类、管状蠕虫等化能自养生物群，圈定出该陆坡由天然气水合物气体“冷泉”喷溢形成的巨型碳酸盐岩面积达430km^2。     

冬小麦夏玉米土壤水分预报及优化灌溉模型

利用土壤水分平衡方程，结合河南省冬小麦和夏玉米的生长规律和1994～2000年冬小麦、夏玉米田实测土壤湿度资料，建立了河南省冬小麦、夏玉米土壤水分预报及优化灌溉的计算机模型。用1998～1999年郑州市麦田实测土壤湿度资料验证该模型模拟结果，未来10、20、30天土壤湿度相对误差分别为-7．3％～7．7％、-8．3％～6．8％、-7．6％～7．7％，表明利用该模型，可以较为准确地预报未来1个月的土壤水分变化，并可根据小麦、玉米不同发育期特点，给出以最高产量和最佳经济效益为目标的灌溉建议。     

A response‐based decoupling criterion for multiply‐supported secondary systems

It is often infeasible to carry out coupled analyses of multiply‐supported secondary systems for earthquake excitations. ‘Approximate’ decoupled analyses are then resorted to, unless the response errors due to those are significantly high. This study proposes a decoupling criterion to identify such cases where these errors are likely to be larger than an acceptable level. The proposed criterion is based on the errors in the primary system response due to decoupling and has been obtained by assuming (i) the input excitation to be an ideal white noise process, (ii) cross‐modal correlation to be negligible, and (iii) the combined system to be classically damped. It uses the modal properties of the undamped combined system, and therefore, a perturbation approach has been formulated to determine the combined system properties in case of light to moderately heavy secondary systems. A numerical study has been carried out to illustrate the accuracy achieved with the proposed perturbation formulation. The proposed decoupling criterion has been validated with the help of two example primary‐secondary systems and four example excitation processes. Copyright © 2002 John Wiley & Sons, Ltd.     

EFG法在土体固结中的应用

EFGM作为一种新的数值计算方法，具有只需节点信息而无段单元的特性，故在解固结方程方面有很大的优势。在计算分析中，此法容易构造固结方程的EFGM刚度矩阵和处理不同边界条件。对单面排水等条件的计算结果表明，EFGM在解决固结变形问题上，精度较高，处理边界准确。     

基于ODBC的地震前兆数据批量卸出与转换程序的实现

介绍了CDBC技术、工作流程及数据传递方式；分析了研制数据卸出与转换程序的关键技术及实现方法；描述了程序的组织结构。通过实例说明了该程序在全国前兆台网中心卸载与转换地震前兆数字化的观测数据中的应用。     

Validation through HVSR measurements of a method for the quick detection of site amplification effects from intensity data: an application to a seismic area in Northern Italy

An instrumental validation is attempted of an innovative approach devoted to the quick individuation, from macroseismic data, of site amplification phenomena able to significantly modify seismic hazard levels expected on the basis of average propagation effects only. According to this methodology, two evaluations of hazard are performed at each investigated locality: the former, obtained by epicentral intensity data ‘reduced’ at the site through a probabilistic attenuation function and, the latter, computed by integrating such data with seismic effects actually observed at the site during past earthquakes. The comparison, for each locality, between these two hazard estimates allow to orientate the identification of those sites where local amplifications of earthquake ground motion could be significant. In order to check such methodology, indications obtained in this way from macroseismic data are compared with the estimates of transfer functions performed through the HVSR technique applied to microtremors. Results concerning municipalities located in a seismic area of Northern Italy indicate a good agreement between macroseismic and instrumental estimates.     

A Reconnaissance Method for Delineation of Tracts for Regional-Scale Mineral-Resource Assessment Based on Geologic-Map Data

The U.S. Geological Survey (USGS) is proposing to conduct a global mineral-resource assessment using geologic maps, significant deposits, and exploration history as minimal data requirements. Using a geologic map and locations of significant pluton-related deposits, the pluton-related-deposit tract maps from the USGS national mineral-resource assessment have been reproduced with GIS-based analysis and modeling techniques. Agreement, kappa, and Jaccard's C correlation statistics between the expert USGS and calculated tract maps of 87%, 40%, and 28%, respectively, have been achieved using a combination of weights-of-evidence and weighted logistic regression methods. Between the experts' and calculated maps, the ranking of states measured by total permissive area correlates at 84%. The disagreement between the experts and calculated results can be explained primarily by tracts defined by geophysical evidence not considered in the calculations, generalization of tracts by the experts, differences in map scales, and the experts' inclusion of large tracts that are arguably not permissive. This analysis shows that tracts for regional mineral-resource assessment approximating those delineated by USGS experts can be calculated using weights of evidence and weighted logistic regression, a geologic map, and the location of significant deposits. Weights of evidence and weighted logistic regression applied to a global geologic map could provide quickly a useful reconnaissance definition of tracts for mineral assessment that is tied to the data and is reproducible.