Power Drive Xceed指向式旋转导向系统在渤海某油田的应用

通过对PowerDriveXceed指向式旋转导向钻具外部结构、内部组成以及工作原理的简要说明,对该钻具和泥浆马达钻具在安全性、时效性2方面进行了对比。最后通过PowerDriveXceed指向式旋转导向钻具在渤海某油田的应用,进行了其与泥浆马达钻具在轨迹控制、机械钻速以及近钻头连续井斜方位的对比分析,给出了渤海在水平井常用的泥浆马达钻具和PowerDriveXceed指向式旋转导向钻具的使用模式,为其它地区使用该工具提供了参考经验。     

湿润地区垃圾填埋场蒸发蒸腾覆盖层参数分析

蒸发蒸腾覆盖层相比传统覆盖层有许多优势,目前这种覆盖层主要应用于干旱和半干旱地区,但研究湿润地区垃圾填埋场蒸发蒸腾覆盖层的水分运移规律和工作性能很有必要。通过二维饱和-非饱和模型,分析覆盖层厚度、土壤类型、植被条件、气候条件等设计参数对蒸发蒸腾覆盖层防渗性能的影响,并对覆盖层中的水分运移规律及其工作性能和适用性进行研究。研究结果表明,随着覆盖层厚度和叶面积指数LAI增加,蒸发蒸腾覆盖层的最终透水量（穿过覆盖层水分）呈减小趋势,但覆盖层厚度和叶面积指数较大时透水量减小趋势不明显;拥有较大储水能力和适当渗透系数的覆盖层能够有效地减少透水量;降雨的季节性分布对蒸发蒸腾覆盖层性能有很大影响,当多雨期与高温期分布一致时,蒸发蒸腾覆盖层的性能可满足设计要求;在非饱和条件下,毛细阻滞型覆盖层利用粗-细粒土之间水力特性的差异形成毛细阻滞效应减少水分向下入渗,其防渗性能优于单一土层型覆盖层,但在不利气象条件组合下,该毛细阻滞作用可能失效, 其防渗性能将大大下降。     

中国粮食生产时空格局动态及其优化策略探析

新中国成立以来,中国粮食生产总体上呈现波动上升的趋势,在区域上粮食生产重心出现"北进中移"的态势,粮食产销格局已由"南粮北调"转变为"北粮南调".利用相关统计资料,简要分析了中国粮食生产变化趋势.从生产和消费角度,基于区域粮食产量差异和比较优势指数模型,对1990-2005年各地区粮食生产的区域变化进行了定量分析,其结果验证了我国粮食生产格局变动的总体特征.在全国人均粮食产量略有增加的背景下,部分省区人均粮食占有量有不同程度的降低,尤其是沿海经济发达省区的粮食生产呈现快速下降态势.为了保障国家粮食安全,应当在发掘各地区粮食生产潜力的同时,充分发挥粮食作物的区域比较优势,保障和稳定基地化的农业生产,着力提高粮食综合生产能力.     

广西凤山岩溶国家地质公园典型地质遗迹景观价值

广西凤山岩溶国家地质公园是我国西南喀斯特旅游资源的富集带,岩溶遗迹景观种类多、规模宏大、特色鲜明。园区内的岩溶洞穴、天生桥、天坑和天窗等4类典型地质遗迹景观与国内外同类景观对比,洞穴通道规模世界最大、巨型洞穴厅堂数量多、密度大;形态巨大、景观奇特的地下河三门海天窗、以高大石笋为代表的洞穴沉积物世界罕见,世界上最大的洞内天生桥,均具有很高的美学观赏价值和科学价值,地质遗迹景观资源的典型性、稀有性、自然性均在同类地质遗迹中名列前茅。     

新疆产业结构效益的实证分析

采用比较劳动生产率、就业产业结构偏离度和偏离一份额分析模型,从不同角度分析1978-2007年新疆产业结构效益.结果显示:新疆三次产业比较劳动生产率差异较大,除第二产业比较劳动生产率较高外,其他产业较小;就业产业结构偏离度大,产值结构和就业结构极不对称;三次产业均为全国性增长产业,西部大开发以来产业竞争能力有所增强;但区域衰退及夕阳产业的比重过大,产业结构层次低、效益较差,有待进一步调整、优化.     

海面微波辐射特性测量与分析

在对海面微波辐射特性现场测量和数据处理的基础上,结合对海面微波辐射理论的初步分析,研究了各种环境参数以及辐射计参数与海洋微波波谱特性的相关关系,为海洋微波遥感资料的分析和解译提供了基础数据.测量结果表明了辐射计参数和环境要素对海面微波辐射特性的影响,而这些影响因素在分析、解译遥感资料时是必需考虑的因素.     

Comparative study of platinum-group elements in the Coto and Acoje blocks of the Zambales Ophiolite Complex, Philippines

Abstract The Zambales Ophiolite Complex (ZOC), Philippines, includes two geochemically distinct, ophiolitic assemblages: the high-Al chromitite-bearing Coto Block and high-Cr chromitite-bearing Acoje Block. This paper reports a comparative platinum-group element (PGE) study of these two blocks. The PGE data were obtained using Ni-sulfide fire assay preconcentration combined with inductively coupled plasma mass spectrometry (ICP-MS) measurement. Podiform chromitites in the Acoje Block have higher Cu, Ir, Ru and Rh contents than their equivalents in the Coto Block, although chromitites from both have similar Pt and Pd contents. The PGE mantle-normalized patterns of dunites from the two blocks are also different: dunites from the Coto Block are depleted in Pt, whereas those from the Acoje Block have a relatively flat pattern. The data demonstrate that Coto and Acoje Blocks have different origins in terms of their source region and partial melting processes. This study implies that the ZOC is a paired ophiolite belt formed in an island arc and back-arc basin environment.     

Wave dispersion in dry granular materials by the distinct element method

Numerical studies are conducted to investigate the existence of wave dispersion in resonant column tests on dry granular soil. To this end, the two-dimensional distinct element method (DEM) in the time domain is employed. The investigations focus on the effect of sample width, voids ratio, viscous damping and wavelength, on propagation velocities of longitudinal harmonic waves in rectangular samples of uniform grains. It is shown that granular materials may exhibit anomalous dispersion that is, wave velocities that increase with increasing excitation frequency. This increase may exceed 20% for squatty samples, but becomes less pronounced for slender samples. Similar findings have been reported in some experiments on granular materials, but have not been systematically explored by numerical means. Results are presented in the form of dimensionless graphs and charts that elucidate the salient features of the problem. Comparisons with findings from gradient elastodynamic and viscoelastic theories are discussed.     

两种土石坝型应力和变形特性的比较分析

结合某在建水库大坝的粘土直心墙和斜心墙两种坝型方案,分别在静力和地震力作用下对坝体在竣工期和运行期的变形、应力及坝体的稳定性进行了计算,从应力、变形和安全的角度对两种坝型的优劣进行了比较分析,得出了一些有益的结论,可以为类似工程及设计提供参考。     

DISPLACEMENT HISTORY OF THE GANGDESE THRUST, ZEDONG WINDOW, SOUTHEASTERN TIBET

DISPLACEMENT HISTORY OF THE GANGDESE THRUST, ZEDONG WINDOW, SOUTHEASTERN TIBET