钻孔走向偏斜的初步探讨

在急倾斜构造部位大力使用硬合金回转钻进时,常常会产生弯曲度很大的走向偏斜情况。这是因为不同岩层的阻力差异使钻头受到一种平行于岩层走向的偏斜力,迫使钻头向侧方研磨井壁;在不同井径变换部位所产生的偏斜效果是不同的。这样造成钻孔沿地层走向发生有规律的定向偏斜。     

广义付里叶变换及其在磁共振成像中的应用

许多共振成像（ＭＲＩ）的应用,要求人体组织磁化强度的空间分布Ｆｏｕｒｉｅｒ变换的幅度和相位的精确分离,及利用正交双通道采集时间和空间高分辨图象序列。在传统的基于Ｆｏｕｒｉｅｒ变换的成象方法中,图象序列从一帧空间编码独立地重建得到,因此给定空间分辨率的情况下,每帧空间编码的数量限制了图象序列的时间分辨力;又常通过牺牲空间分辨率来提高图象序列的空间分辨录。由于传统Ｆｏｕｒｉｅｒ变换的核函数是线性相位,若变换ＭＲＩ技术必须很好地满足主磁场均匀性和梯度场线性的条件,因此传统Ｆｏｕｒｉｅｒ变换成象方法对临床应用中常出现ＭＲ信号相位失真极为敏感。本文提出：利用主磁场中组织的磁化强度不变,能很好消除图象的相位失真。     

甘肃省暴雨初探

着重分析甘肃省的暴雨特性与时空分布规律,列举了历年实测和调查最大点暴雨特征值,绘制了短历时暴雨～高程相关线、选配丁甘肃最大点暴雨外包线公式,对历年各时段最大暴雨均值、极值、Cv、Cs值等暴雨参数及典型暴雨时程分配和面时关系线等方面作了初步探讨。     

Managing Soil Erosion Potential by Integrating Digital Elevation Models with the Southern China's Revised Universal Soil Loss Equation——A Case Study for the West Lake Scenic Spots Area of Hangzhou,China

In China,many scenic and tourism areas are suffering from the urbanization that results from physical development of tourism projects,leading to the removal of the vegetative cover,the creation of areas impermeable to water,in-stream modifications,and other problems. In this paper,the risk of soil erosion and its ecological risks in the West Lake Scenic Spots (WLSS) area were quantitatively evaluated by integrating the revised universal soil loss equation (RUSLE) with a digital elevation model (DEM) and geographical information system (GIS) software. The standard RUSLE factors were modified to account for local climatic and topographic characteristics reflected in the DEM maps,and for the soil types and vegetation cover types. An interface was created between the Arcinfo software and RUSLE so that the level of soil erosion and its ecological risk in the WLSS area could be mapped immediately once the model factors were defined for the area. The results from an analysis using the Arcinfo-RUSLE interface showed that the risk value in 93 % of the expanding western part of the WLSS area was moderate or more severe and the soil erosion risk in this area was thus large compared with that in the rest of the area. This paper mainly aimed to increase the awareness of the soil erosion risk in urbanizing areas and suggest that the local governments should consider the probable ecological risk resulting from soil erosion when enlarging and developing tourism areas.     

色尔腾山山前断裂得令山以东段晚第四纪活动特征与古地震事件

色尔腾山山前断裂得令山以东段属全新世活动断裂。距今约 30ka以来 ,断裂上升盘的平均抬升速率为 :大佘太段 0 19mm/a ,乌兰忽洞段 0 2 0mm/a。探槽揭露 ,大佘太段 ,约 32kaBP以来 ,发生过 4次古地震事件 ,事件发生时间依次为 (316 90± 1770 ) ,(2 30 0 0± 132 0 ) ,(15 42 0± 870 ) ,(74 40± 4 40 )aBP ,相应的位移量分别为 2 6 ,1 6 ,2 2 ,1 4m ;乌兰忽洞段 ,约 2 5kaBP以来 ,也发生过4次古地震事件 ,事件发生时间依次为 (2 5 130± 14 30 ) ,(14 5 70± 82 0 ) ,(116 6 0± 6 5 0 ) ,(72 2 0± 4 0 0 )aBP ,相应的位移量分别为 2 6 ,1 8,1 3,1 2m。根据位移量限定法 ,两个活动段落的古地震活动历史是完整的     

Characterization of stabilized waste: Evaluation of pollution risk

This study relates to the characterization of stabilized waste. Various parameters such as granulometric distribution, percentage of mineral and organic matter were estimated to appreciate environmental hazard potential and possibility of metal leaching of the samples of waste from Grange site in France. From the results, it was shown that the granulometric distribution was variable. Therefore, a strong proportion of fines (44.6 %) and medium (45.9 %) was observed due to the age of waste that supports the degradation of a great quantity of organic matter. That was confirmed by the strong mineral matter rate (63.8 %) obtained to determine the organic percentage of matter (36.2 %). The amount of heavy metals such as iron, nickel, copper, zinc, cadmium and lead was also studied. The results obtained were in a good agreement with the ones of the literature. Indeed, it appeared that iron, lead, copper, nickel and zinc are in relative strong proportion while cadmium was not very present. Iron represents 78 % of the metals. From the leaching tests, it was shown that the heavy metals concentration were very weak. Moreover, the deposit of studied waste could be a potential source of organic pollution (COD = 150 Mg C/L on average) in the case of precipitation and flood.     

青藏高原多年冻土区水文地质特征

青藏高原多年冻土区的地下水是高原特定的地质地理环境下的产物,多年冻土的存在控制地下水的形成和分布,新构造运动是影响区域水文地质条件的主导因素,地下水和多年冻土相互作用、相互制约,导致区域水文地质条件复杂化。     

上海某冻结加固工程试验研究分析

通过对上海某冻结加固工程试验研究分析，提出了应针对上海地区软土矿物成分及水平渗透性强的特点，在开放系统中进行土体低温特性研究；同时就地下水的含盐量，土体冻结速率，土粒粒径，分散度等对土体低温特性的影响也提出了一些个人看法。     

宁夏南部地区水质形成机制研究

宁夏南部地区是中国严重缺水地区之一,该地区地下水类型可分为松散岩类孔隙水、碎屑岩类裂隙-孔隙水、基岩裂隙水和碳酸盐类岩溶水。受到当地特殊的气候条件、地貌特征、地层岩性和地质构造的影响,各类地下水水质普遍比较差。含水介质中大量的石膏、芒硝等矿物成分进人地下水中是水质恶劣的根本原因;封闭的蓄水构造使得当地地下水循环不畅,蒸发浓缩作用使得浅层水中聚集高盐分,也是水质变差的重要原因。     

上海地区地质构造特征

上海地处扬子准地台的东北端。前晋宁旋回和晋宁旋回属地槽发展阶段,由变质岩系组成地台的褶皱基底。加里东旋回为准地台发展阶段,构造层发育齐全,为海相、浅海相连续沉积。印支运动结束了本区长期海侵的历史,开创了滨太平洋大陆边缘活动的新纪元。燕山旋回构造变动、岩浆活动十分活跃。喜马拉雅旋回地壳振荡运动频繁。