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建筑密集区高倾角三维地震勘探效果 总被引：2，自引：1，他引：2
高倾角地区(地层倾角40～70°)一直是三维地震勘探的难题,特别是在地表建筑物极复杂区(占工区的95%)实施三维地震勘探,显得难度更大。本文从观测系统设计、炮点、检波器的特殊布设及特观设计上,论证了其可行性。对高倾角且建筑物密集区的三维地震勘探进行了探索,并取得了可喜的成果。 相似文献
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Based on recent experiments carried out in wave basin on breakwaters with armour layer of rocks and cubes, this paper examines the dependence of the reflection coefficient on wave directional spreading and obliquity. Results suggest that long-crested and short-crested waves give similar reflection. The reflection coefficient is markedly dependent on the wave angle of incidence. The performance of formulae available in the literature is checked against the new dataset and a significant improvement is proposed by including the wave obliquity factor that appears in the traditional expression for the overtopping discharge. 相似文献
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蒋志 《矿物岩石地球化学通报》2001,20(3):165-171
本文讨论了地球内部长寿期放射性同位素衰变能的存量 ,给出地球脉动频率和频数公式 ,并据以重新建立了理论地质年表 ,解释了地球自转变化、地磁场倒转和黄赤交角变化等。 相似文献
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New series of rigid Earth nutations for the angular momemtum axis, the rotation axis and the figure axis, named RDAN97, are
computed using the torque approach. Besides the classical J2 terms coming from the Moon and the Sun, we also consider several
additional effects: terms coming from J3 and J4 in the case of the Moon, direct and indirect planetary effects, lunar inequality,
J2 tilt, planetary‐tilt, effects of the precession and nutations on the nutations, secular variations of the amplitudes, effects
due to the triaxiality of the Earth, new additional out‐of‐phase terms coming from second order effect and relativistic effects.
Finally, we obtain rigid Earth nutation series of 1529 terms in longitude and 984 terms in obliquity with a truncation level
of 0.1 μ (microarcsecond) and 8 significant digits. The value of the dynamical flattening used in this theory is HD=(C-A)/C=0.0032737674
computed from the initial value pa=50′.2877/yr for the precession rate. These new rigid Earth nutation series are then compared
with the most recent models (Hartmann et al., 1998; Souchay and Kinoshita, 1996, 1997; Bretagnon et al., 1997, 1998. We also
compute a benchmark series (RDNN97) from the numerical ephemerides DE403/LE403 (Standish et al., 1995) in order to test our
model. The comparison between our model (RDAN97) and the benchmark series (RDNN97) shows a maximum difference, in the time
domain, of 69 μas in longitude and 29 μas in obliquity. In the frequency domain, the maximum differences are 6 μas in longitude
and 4 μ as in obliquity which is below the level of precision of the most recent observations (0.2 mas in time domain (temporal
resolution of 1 day) and 0.02 mas in frequency domain).
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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To obtain a better understanding of the oscillatory soil liquefaction around an offshore pipeline, a three-dimensional integrated model for the wave–seabed–pipeline interaction (WSPI) is proposed by combining the Reynolds-Averaged Navier–Stokes equations for flow simulations and the dynamic Biot’s equation (“u-p” approximation) for the poro-elastic seabed model. Compared with previous investigations, the wave–current interaction is included in the present WSPI system. At a given time step, the wave pressure extracted from the flow model is applied on the seabed surface to determine the corresponding oscillatory seabed response around an offshore pipeline. The integrated numerical model is first validated using previous laboratory experiments. Then, a parametric study is conducted to examine the effects of flow obliquity and pipeline burial depth on the soil response around an offshore pipeline. Numerical results indicate that the soil under the pipeline is more susceptible to liquefaction at a reduced flow obliquity and pipeline burial depth. Moreover, the liquefaction depth in the case where the wave travels along the current can increase by 10%–30% compared to that in the case where the wave travels against the current, when the magnitude of the current velocity is 1 m/s. 相似文献
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柴北缘油气运移优势通道特征及其控油气作用 总被引：7，自引：3，他引：4
油气运移优势通道研究对于追踪油气运移方向和预测有利勘探目标具有重要意义, 在对柴北缘地区输导层砂体展布、主要成藏期古流体势、断层倾角和区域盖层分割槽等地质条件综合研究的基础上, 分别阐述了级差优势、流向优势、流压优势和分割槽优势等4种类型优势通道的分布特征以及对油气运移的单因素控制作用, 然后进行多因素叠加, 综合分析在4种优势通道共同作用下柴北缘地区的油气优势运移方向, 进而优选勘探目标.结果表明: 冷湖-南八仙构造带具有阿尔金斜坡、赛什腾、鱼卡-南八仙3个大规模沉积体系的级差优势通道, 同时流压优势通道、分隔优势通道和流向优势通道分布范围广, 并且处于昆特依凹陷和伊北凹陷油气的运移指向区, 使得该构造带成为最有利的油气聚集带, 其次是鄂博梁Ⅰ号-葫芦山构造带; 冷湖七号东、西高点深层构造和葫芦山构造为最有利的勘探目标, 有望取得新的突破. 相似文献
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刷磨和剔磨是钻石加工者为了尽可能保存钻石成品的克拉质量、又消除腰棱附近瑕疵时采取的加大或减小腰小面倾角的加工措施,磨钻师傅往往凭经验掌握。利用本文编写的刷磨与剔磨工艺参数计算程序,可以准确计算出任意切工参数下指定的刷磨或剔磨程度所对应的工艺参数。 相似文献
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CTM—DI磁通门经纬仪观测操作方法 总被引：2，自引：0，他引：2
CTM—DI磁通门经纬仪是一种性能优良的国产地磁测量仪器，使用方便，精度较高，对于相对记录数字化后基线值的确定具有不可或缺的重要作用，在观测实践中理论联系实际，对磁通门经纬仪观测操作方法进行研究总结。 相似文献