深水拖曳式大功率时频发射与多链缆多分量电磁探测系统

海洋可控源电磁探测方法是目前海洋油气资源勘探和海底地质构造调查中不可或缺的物探手段之一.本文研究的深水拖曳式大功率时频电磁发射与多链缆多分量电磁探测系统,是深水双船拖曳式可控源海洋电磁勘探系统的关键组成部分.发射系统利用深拖缆实现了电能在复杂海洋环境下长距离、大功率和低损耗传输,基于大功率变流拓扑结构攻克了2000 A量级、0.01~16 Hz可控的时频域大电流冲击脉冲发射;接收系统建立了主节点与最多5个从节点的数据链接,单个从节点记录到了三轴正交的电磁场分量以及运动姿态信息.海洋试验表明,深水双船拖曳式海洋可控源电磁勘探系统借助发射系统与接收系统之间的时间同步、时频观测、可变收发距和观测装置等技术优势,显著提升了数据质量和有效的数据数量,为后续处理和反演提供了硬件支撑.经过海上试验,整套系统的技术性能得到多次验证,未来有望在深水油气、天然气水合物和海底硫化物等资源勘查以及海底地质构造调查领域获得广泛应用.

     

Geophysical Well-Log Evaluation in the Era of Unconventional Hydrocarbon Resources: A Review on Current Status and Prospects

Surveys in Geophysics - Geophysical well-log evaluation in the era of unconventional hydrocarbon resources (mainly tight oil and gas, shale oil and gas) is complicated and challenging. This review...     

Temporal and spatial statistics of travelling eddy variability in the South China Sea

Ocean Dynamics - The variability across decades of years of migrating eddy activities in the South China Sea (SCS) has not yet been documented. We employ a daily global eddy-resolving (0.1°)...     

Hydrogeochemical Evolution of Interaction Between Surface Water and Groundwater Affected by Exploitation

Hydrogeochemical evolution of interactions between surface water and groundwater is crucial for guaranteeing water supply quality in a riverside water source area. This study focuses on the seasonal and spatial characteristics of hydrogeochemical evolution affected by groundwater exploitation in the Hulan water source area using hydrochemical analyses and stable isotope tracers. Results show that the concentrations of major ions and total dissolved solids (TDS) increase considerably during the dry season. A bicarbonate water type is primarily produced by the dissolution of calcite, dolomite and gypsum, as well as the cation exchange and human activities. Along the typical infiltration path, the proportions of surface water increase with proximity to the river from 8%-63% during the wet season to 11%-84% during the dry season, which are attributed to an increased hydraulic gradient by exploitation. The typical path is classified into two zones. The first is the intensive mixing zone (within 1 km) with increasing concentrations of major ions and TDS due to mixing effect. The second is the exploitation influence zone (1-3.3 km) with increased concentrations of Ca²⁺, Mg²⁺, SO₄²⁻, and HCO₃⁻ during the dry season due to two reasons of seasonal variations in evaporation, stronger water-rock interactions and mixing effects with increased surface water by exploitation.     

宁波站DDL-2与FD-105K测氡仪对比观测研究

测氡仪对比观测研究是探索仪器运行规律和提供可靠地震研究数据的支撑。文章基于使用AlphaGUARD P2000测氡仪作为无源标定仪器对DDL-2测氡仪进行溶解氡的校准实验,开展DDL-2测氡仪氡浓度响应研究以及DDL-2测氡仪和FD-105K测氡仪对比观测研究。结果表明：(1)校准K值的偏差值都在4.827 6%以内,满足目前地震监测观测技术要求和仪器标定要求;(2)DDL-2测氡仪可描述动态的水氡浓度,使用Origin 2018数据分析软件对氡浓度绘制拟合曲线,为氡值变化过程提供数学模型,鼓泡过程中水氡浓度经历迅速上升期、平缓期和稳定期,稳定后氡浓度变化幅度约为5.0 Bq/L,并且变化形态不尽相同;(3)使用Origin 2018对比分析数据,发现DDL-2测氡仪与AlphaGUARD P2000测氡仪较FD-105K测氡仪氡浓度日变化响应更灵敏且氡测值曲线吻合度更高。     

Comprehensive Combustion Performances of Water Hyacinth and Pistia stratiotes Pellet Fuels

For efficient combustion of aquatic biomass, the effects of heating rate on the combustion and dynamic characteristics of two typical aquatic species (water hyacinth, Pistia stratiotes), and the effects of temperature and additives on ash K and Cl concentrations are studied. The two types of pellets have ignition temperatures of 252.7 and 250.3 °C, respectively. At a heating rate of 10 °C min⁻¹, where combustion is most stable, the comprehensive combustion efficiencies reach their maximum at 4.7 × 10⁻⁶ and 2.2 × 10⁻⁶ mg²min⁻¹°C⁻², respectively. The K and Cl concentrations in the ash decrease steadily with increasing temperature, falling to 10.3% and 0.41% for water hyacinth and 11.1% and 1.85% for P. stratiotes, respectively. X-ray diffraction (XRD)shows that abundant Ca minerals form in the ash after the addition of CaO, which inhibit KCl formation, and K and Al silicates form in the ash after the addition of kaoline, which reserve K in the ash. These findings provide a starting point for the development of efficient aquatic biomass combustion.     

改进的一阶弹性波方程交错网格高阶差分解法

本文对董良国、马在田等人发表在<地球物理学报>上的一阶弹性波方程交错网格高阶差分解法一文进行了差分格式的改进.发现原文对一阶空间导数采用2N阶差分精度,而对高阶导数却采用简单的中心差分,即对同一方程中的各阶导数的处理存在有的采用高阶格式、有的采用低阶格式的不一致性问题,本文的改进点正是消除了这种不一致性,建立了时间和空间均为四阶精度的差分格式.该方法具有编程简便、易于计算机实现和精度较高的特点.     

钢筋笼长度检测技术现状及展望

详细介绍了电磁波法、声波法、瞬变电磁感应法、磁法和电法的灌注桩中钢筋笼无损长度检测地球物理方法,并对每一种方法进行了评价.提出了磁测井法和电测井法是目前可靠和实用的钢筋笼长度无损地球物理检测方法.鉴于检测前需要在桩旁或桩中钻孔导致检测速度慢、检测费用高,使得钢筋笼长度无损地球物理检测大规模实施困难,建议利用电法中的二极装置开展在地面上能进行钢筋笼长度检测方法的研究.     

大庆台网观测效果分析与振动事件研究

应用周期－频度谱和复查分析等方法对大庆台网观测资料进行详细研究，从而取得了对台网的监测能力，其些小事件的性质等问题的明确认识。     

东北地区浅源中强震及深震与西太平洋板块俯冲

本文研究了１９９０年以来东北地区的浅源中强震和深震的相关关系，还讨论了板块俯冲对东北地区的影响，结果表明，东北地区浅源地震与深源地震存在着相关活动的特点。