构造煤结构与煤层气赋存研究进展

碎软煤的完整原样制取困难,需要加工制成重塑煤体,为了研究不同压制荷载对煤体物性特征的影响,以重塑煤体为研究对象,基于低温液氮的孔隙测试实验和高压容量法的甲烷吸附实验,探讨不同成型荷载而成的重塑煤体的微小孔结构及其吸附特性的差异。结果表明：不同成型荷载压制而成的重塑煤体,其微孔和小孔的孔容随着成型荷载的增大而略微减少,孔比表面积随着成型荷载的增大而略微增加,总孔体积减少和孔比表面积增加的幅度不大;通过分形理论发现无论高压段还是低压段,孔隙结构具有明显的分形特征,且在高压段的分形维数普遍低于低压段,不同荷载压制而成的重塑煤体的分形维数差别不大;等温吸附线均符合第Ⅰ类等温吸附曲线,Langmuir模型适用于描述重塑煤体的等温吸附,成型荷载对煤的吸附常数有一定的影响,其对吸附常数b值的影响大于对a值的影响。研究不同成型荷载下重塑煤体的吸附特性,为不同条件下型煤制作及冷冻取心实验提供参考。     

New high-resolution 2D seismic imaging of fluid escape structures in the Makran subduction zone,Arabian Sea

Seabed fluid escape is active in the Makran subduction zone, Arabian Sea. Based on the new high-resolution 2D seismic data, acoustic blanking zones and seafloor mounds are identified. Acoustic blanking zones include three kinds of geometries: Bell-shaped, vertically columnar and tilted zones. The bell-shaped blanking zone is characterized by weak and discontinuous reflections in the interior and up-bending reflections on the top, interpreted as gas chimneys. Vertically columnar blanking zone is interpreted as side-imaged gas chimneys associated with focused fluid flow and topped by a seafloor anomaly expressed as a localized reflection discontinuity, which may together serve as a vent structure. Tilted acoustic blanking zone could be induced by accretionary thrust activity and rapid sedimentation surrounding slope. Seafloor mounds occur at the sites of bell-shaped acoustic blanking zone and may be associated with the material intrusion. Bottom simulating refectors (BSRs) are widely distributed and exhibit a series of characteristics including diminished amplitude, low continuity as well as local shoaling overlapping with these acoustic blanking zones. The large amount of gases dissociated from the gas hydrates migrated upwards and then arrived at the near-seafloor sediments, followed by the formation of the gas hydrates and hence the seafloor mound.     

耐久性设计下水土腐蚀性评价体系的一种解决方案

水土腐蚀性评价标准与混凝土结构耐久性设计的防护标准是相互作用,相互影响的。本文通过2个地下水实例,比较了桩基础和地下室底板在不同规范体系下水土腐蚀性评价标准和防护标准的差异。腐蚀环境越严重,混凝土结构耐久性设计差异越大,因此,有必要统一水土腐蚀性评价标准和混凝土结构耐久性设计的防护标准。针对SO42-和CL-腐蚀性评价差异较大的情况,本文给出了干湿交替作用及其强度的定义,提出了一种统一水土腐蚀性评价指标及其分级的建议方案。干湿交替作用是指在固体表面能够形成液相水与气相水交替转换或持续转换的一种现象,干湿交替作用强度定义为固体表面液态水的相对蒸发速率和固体表层饱和度的乘积。     

南海东北部洋陆过渡区域地震折射波衰减特征

地震波衰减研究是了解岩石圈构造特征的有效方法.本文基于OBS2016-2测线的海底地震仪(OBS)数据, 首次对南海东北部洋陆过渡区域地震波衰减特征进行研究, 通过正演模拟获得该区域二维纵波衰减(Q_P)结构.结果表明, 下陆坡的上地壳存在一个宽约40 km, 厚度约为4~5 km的高衰减区, 其特征为低纵波和横波速度(V_P为5.5~6.3 km·s^-1和V_S为3.1~3.6 km·s^-1)以及较低的波速比(V_P/V_S为1.72~1.80), 对应较低的Q_P(280~410), 推测与断裂发育有关, 且受到火山活动的影响.洋陆过渡及洋壳区域的上地壳高衰减区具有低Q_P(300~400)和高V_P/V_S(1.90~1.96)特征, 可能对应较多的断裂发育及流体运移.洋陆过渡区域下地壳高速异常体表现为相对低的Q_P(550~600), 对应较高的V_P(7.0~7.8 km·s^-1)和V_S(3.5~3.8 km·s^-1)以及较高的V_P/V_S(1.85~1.96), 推测与蛇纹石化作用有关.蛇纹石化可能进一步增加岩石的孔隙度并导致更多的流体运移, 使得洋陆过渡及洋壳区域存在较高的地震波衰减.Q_P结构有助于我们分析南海大陆边缘的地震波衰减特征, 结合V_P、V_S以及V_P/V_S, 可以更好地了解该区域地质结构和岩石属性, 对进一步挖掘OBS数据信息有重要参考价值.

     

GeoSwath相干多波束系统原始数据的解析

通过分析GeoAcoustics公司的GeoSwath相干多波束系统的二进制原始文件结构,使用VC 6.0设计出各传感器字段的数据结构,并编程实现相干多波束数据的提取和图形可视化。该技术方法对于GeoSwath系统多波束数据的提取和分析处理有参考意义。     

Effects of pulsed nutrient inputs on phytoplankton assemblage structure and blooms in an enclosed coastal area

The response of phytoplankton assemblage structure to terrestrial nutrient inputs was examined for the Gulf of Kalloni in the Northern Aegean Sea, a productive semi-enclosed coastal marine ecosystem. The study was focused on a typical annual cycle, and emphasis was placed on the comparative analysis between blooms developing after significant nutrient inputs from the watershed, and naturally occurring blooms. Baseline information was collected on a monthly basis from a network of stations located in the oligotrophic open sea and the interior and more productive part of the embayment. Intensive sampling was also carried out along a gradient in the vicinity of a river which was the most important source of freshwater and nutrient input for the Gulf. Phytoplankton assemblage structure was analyzed from 188 samples using diversity indices (Shannon and Average Taxonomic Distinctness), multivariate plotting methods (NMDS), multivariate statistics (PERMANOVA), and canonical correspondence analysis (CCA). Three characteristic assemblages were recognized: (1) an autumn assemblage developed under nutrient depleted conditions, having low diversity due to the dominance of two small diatoms, (2) a winter bloom of the potentially toxic species Pseudo-nitzschia calliantha occurring immediately after a nutrient peak and characterized by very low diversity, and (3) a naturally occurring early summer bloom of centric diatoms with relatively high diversity. The results of the study support the view that moderate nutrient inputs may have a beneficial effect on the functioning of coastal ecosystems, stimulating the taxonomic diversity through the growth of different taxonomic groups and taxa. On the other hand, a sudden pulse of high nutrient concentrations may greatly affect the natural succession of organisms, have a negative effect on the diversity through the dominance of a single species, and can increase the possibility of a harmful algal bloom development.     

变异函数在水深场空间结构分析中的应用

引进了地统计学中的变异函数,通过对我国多幅航海图和港湾图水深数据的计算分析,初步揭示了水深场的空间变异特征.结果表明:水深点的空间相关性与相互间的距离和所表征的海底地形有关;在不同的尺度下水深场的空间变异特征不同;水深场的空间变异存在各向异性.     

0903号台风“莲花”的风结构分析

通过对0903号台风“莲花”在登陆福建晋江并沿着海岸线北上过程中的沿海自动站逐时实况风场资料的分析,研究了该台风的风结构状况,得到以下结论：（1）台风近中心最大风速预报值比实测风速偏小,台风7级风半径则比实际的偏大．（2）实测2min平均风速最大值（Vmax）总体上呈减弱趋势,与时间（t）的回归方程式为：Vmax=28．9—0．61t（n=16,r=0．78,r005=0．50）．（3）台风最大风速半径（R）呈逐渐扩大的趋势,与时间（t）的回归方程式为：R=28．28—4．98t＋0．67t。（n=16,r=0．95,r0.05=0．50）．（4）台风最大风速区位于台风后部．认识台风风结构,有助于不断地提高预报的准确性．     

浙闽沿岸流消退时期的浮游植物群落结构特征

浙闽沿岸流对台湾海峡的水文环境意义重大.依据国家海洋局"908"补充调查专项,通过对覆盖浙闽沿岸流海洋锋面过程的海洋生物调查研究,于2008年4月实施针对浙闽沿岸流消退时期(春季)台湾海峡锋面海域的浮游植物取样分析.结果共记录3门41属86种,其中硅藻35属76种.甲藻5属9种,蓝藻1属1种.种类组成以暖水性种类和广布...