华北地区重力场变化特征与孕震模型研究

本文采用基于贝叶斯原理的重力平差方法对华北地区2009—2017年的16期陆地流动重力观测资料进行了统一处理,结合研究区内2009年以来4次M≥4.5 地震活动,分析区域重力场动态演化特征。基于华北地区均衡重力异常、布格重力异常、沉积层重力异常和莫霍面重力异常,研究华北地区三维密度结构特征,分析区域重力场变化与深部密度结构之间的关系。结果表明:研究区内近年来M≥4.5地震均位于区域差分重力场和累积重力场“零值”等值线附近、异常变化剧烈的梯度带及梯度带转弯部位,以及深部结构中理论均衡厚度与实际地壳厚度存在差异的非均衡区和三维密度结构的高低密度过渡带内。      

基于优化滤波法对芦山地震震区重力异常特征的分析

首先对具有代表性的重力异常分离方法进行简单介绍, 在此基础上使用这些方法对同一组理论模型数据进行试验, 优选出异常分离效果较好的优化滤波法对芦山地震震区重力异常特征进行分析, 初步认识此次地震发生的深部构造背景, 得出以下初步结论: 龙门山断裂带在研究区布格重力异常中反映为一条近北东走向的显著重力梯度带. 该梯度带在天全附近分为两支, 芦山地震震区靠近重力梯度带分叉处, 且M_S≥3.0余震同样呈近北东向展布, 与梯度带走向基本一致, 认为此次强地震的发生与重力梯度带下的深部结构及构造活动密切相关; 芦山地震震区浅部结构与深部构造特征存在较大差异, 构造复杂及地壳深浅部耦合关系较差, 说明此次强地震的发生受浅部和深部构造的共同控制.      

Effects of salt solutions on the hydro-mechanical behavior of compacted GMZ01 Bentonite

In this study, the effects of salinity of infiltrating solutions on the swelling strain, compressibility, and hydraulic conductivity of compacted GMZ01 Bentonite were investigated. After swelling under vertical load using either distilled water or NaCl solutions with concentrations of 0.1, 0.5 M, and 1 M, laboratory oedometer tests were conducted on the compacted GMZ01 Bentonite. Based on the oedometer test results, hydraulic conductivity was determined using the Casagrande’s method. Results show that the swelling strain of highly compacted GMZ01 Bentonite decreases as the concentration of NaCl solution increases. The compression index C _c ^* increases and then turns to decrease with an increase in the vertical stress or a decrease in the void ratio for different solutions, and the C _c ^* decreases as the concentration of NaCl solution increases. The secondary consolidation coefficient C _α increases linearly with the increase of the compression index C _c ^* . Furthermore, a bi-linear relationship between the swelling index C _s ^* and the secondary consolidation coefficient C _α can be characterized clearly. The hydraulic conductivity increases as the concentration of NaCl solution increases, however, this increase can be prevented if a high confining stress is applied.     

内蒙古科尔沁右翼中旗地区孟恩陶勒盖岩体成因研究

内蒙古东部科尔沁右翼中旗地区孟恩陶勒盖岩体由二长花岗岩、 花岗闪长岩、 英云闪长岩组成,属于高钾钙碱性岩系。岩石具有SiO₂较高（平均为72.03%）,富碱并相对富K₂O（K₂O/Na₂O平均为1.08）,Mg^#较低（平均为0.30）,铝饱和指数（A/CNK）较高（平均为1.08）的特点。在ACF图解中,岩石投影在S型花岗岩中,标准矿物中普遍出现刚玉分子,岩石中可见白云母,个别可见石榴石,应属S型花岗岩范畴。岩石稀土总量较低（∑ REE平均为120.76×10^-6）,轻、 重稀土分馏明显（（La/Yb）_N=3.2～32.5）,有变化较大的负铕异常（0.2～0.8）;在微量元素蜘蛛网图上,强烈富集大离子亲石元素（如Rb、 Ba）,高场强元素（如Ti）强烈亏损,在微量元素与上陆壳标准化及（La/Yb）_N-δEu图解中,物源属于壳源。岩体Sr的含量平均为176.57×10^-6,小于300×10^-6,Yb含量平均为1.3×10^-6,小于2×10^-6,属于喜马拉雅型花岗岩,源岩可能为含石榴石和斜长石的高压麻粒岩相,形成于加厚地壳部分熔融的结果,其形成的压力可能为0.8～1.5 GPa。在R₁-R₂图解、 Yb-Ta图解中,岩石均投影在同碰撞环境。因此,该岩体是中三叠世挤压背景下同碰撞壳源S型花岗岩,为华北板块与西伯利亚板块碰撞上限的约束提供了资料。     

黄海鱼类食物网的研究

于1985年3月—1986年10月和1988年5月间,对黄海海域40科69属80种鱼的食性及其相互关系进行了较系统地调查、分析。结果表明:1.黄海鱼类饵料分为4个生态类型;2.黄海鱼类摄食有明显的季节变化;3.黄海鱼类基本属于第二—第四营养级;4.日本鳀、脊尾褐虾、太平洋磷虾等优势饵料生物在黄海鱼类食物网中起着举足轻重的作用;5.黄海多数鱼类间的食物竞争关系基本是协调的。     

卫星信号仿真电离层闪烁模型研究

电离层闪烁会导致地空无线电信号产生随机起伏,影响各种地空信息系统的工作性能.为了满足电离层闪烁影响效应评估的应用需求,建立了一个卫星信号电离层闪烁模型.该模型是在对闪烁信号衰落特性进行统计分析的基础上建立的,它将信道函数分为直接分量和随机多径成分两部分.模型可根据输入的电离层闪烁指数和去相关时间仿真出信号振幅和相位的变化,并可直接嵌入到各类卫星信号模拟器中,用于卫星导航、卫星通信等系统的衰落信道仿真.     

Low-cost attitude estimation with MIMU and two-antenna GPS for Satcom-on-the-move

We detail a low-cost method to estimate vehicle attitude for Satcom-on-the-move (SOTM) using micro inertial measurement unit and two-antenna global positioning system (GPS). The attitude is calculated by integrating gyros, while accelerometers and GPS are used as an aiding system to calibrate the gyro biases. In order to accurately eliminate the accelerometer errors induced by maneuvering accelerations, a sideslip compensation is proposed to calibrate the acceleration estimation derived from the GPS-measured velocity. An adaptive unscented Kalman filter is then developed to deal with the failure of the two-antenna GPS to provide the yaw and sideslip angles. When the yaw angle is unavailable and the vehicle is in straight motion, the yaw angle observation is substituted by velocity heading. During turning, the yaw angle observation is turned off and the yaw angle estimates are obtained from integrating gyros only. Meanwhile, the sideslip angle is estimated by differencing the yaw angle estimate and the velocity heading. The performance of the proposed method is demonstrated with driving tests, suggesting that this technique is a viable candidate for low-cost SOTM.     

A pneumatic shaking table and its application to a liquefaction test on saturated sand

The shaking tables that are used in earthquake engineering are normally driven by hydraulic actuators, which require high maintenance and operation costs. In some studies, when it is only desirable to conduct small-scaled model tests, a pneumatic shaking table can be considered as an alternative to a hydraulic shaking table. This paper describes the design, development, calibration, and performance of a pneumatic shaking table system. It was proved that the pneumatic shaking table can offer satisfactory performances. Using the pneumatic shaking table, a liquefaction test on saturated sand was conducted. During liquefaction, both the stiffness and acceleration response of the ground greatly decreased. In comparison to the sharp increase in excess pore water pressure (EPWP) when liquefaction started, the dissipation process lasted for a much longer time period.     

抗差估计在自由落体式绝对重力仪中的应用

针对自由落体式绝对重力仪中的异常数据,提出抗差参数估计的数据处理方法。对比分析传统最小二乘拟合与抗差最小二乘拟合计算的重力值,结果表明,抗差参数估计通过合理调整权重因子抑制了异常数据的影响,提高了重力测量精度。     

渤海复杂断块油藏精细挖潜的实践与认识

位于渤海的渤西复杂断块油田群由4个储量均为约1 000×10^4m^3的复杂断块油田组成。油田群内部断层发育,含油层系多,油气水关系复杂。经过长期衰竭开发,地层能量下降快、各层采出不均衡、剩余油分布复杂,开发效果逐渐变差。为了解决开发过程中出现的诸多突出矛盾,通过动静结合、精细地质研究寻找剩余油;通过晚期加强注水、细分开发层系缓解层间矛盾;通过老井上返、滚动勘探开发等方法实现产量接替。这些方法的研究与应用,延长了海上老油田的开发寿命,提高油田采收率5%～12%,对于海上复杂断块油田的精细挖潜和高产稳产具有重要的指导作用。