Numerical investigation of the hydrodynamic response of an impermeable sea-wall subjected to artificial submarine landslide-induced tsunamis

Landslides - Landslide-induced tsunamis are common natural hazards that potentially affect the safety and stability of waterfront structures. A numerical tank was constructed using FLOW-3D to...     

广西隆安下石炭统都结微生物岩微相特征与沉积环境研究

广西隆安县都结乡发育的微生物岩产于下石炭统都安组中—上部地层,分布广、厚度大,是中国南方早石炭世报道较少的碳酸盐岩建造类型,具有较高的研究价值。该微生物岩以颗粒灰岩和粘结岩为主,生物含量丰富,包括微生物、有孔虫、棘皮类、钙球、腕足等。通过岩相分析,可识别出以下8种微相类型:MF1含亮晶胶结物的泥晶包壳生屑灰岩、MF2含腕足似球粒灰岩、MF3无纹层似球粒颗粒灰岩、MF4集合颗粒灰岩、MF5细密纹层状粘结岩、MF6内碎屑鲕粒灰岩、MF7鲕粒灰岩、MF8白云质鲕粒灰岩。伴随海平面升降变化,都结微生物岩沉积环境先后经历了FZ1台地边缘浅滩相、FZ2开阔台地相与FZ3局限台地相这三种沉积相带之间往复变化的沉积相模式。结合前人基础地质资料,该沉积相模式表明该微生物岩发育于低纬度孤立碳酸盐岩台地浅水环境,并经历了初期、主体时期和消亡期3个发育阶段,海平面虽伴有小幅波动,但整体呈下降趋势。微生物岩发育于晚古生代冰期与谢尔普霍夫生物灭绝事件前夕,该时期南盘江盆地微生物岩的富集与后生动物礁的缺失相耦合,海洋生态系统中生物组成发生显著变化。在此基础上,本文从微生物岩的角度初步探讨了冈瓦纳大陆冰川作用对北半球低纬度地区的影响。     

砂土的抗剪强度与干密度的曲线拟合

利用曲线拟合的最小二乘法原理，确定砂土在某垂直压力下的抗剪强度与干密度的关系，并绘制曲线图，可避免人工处理数据的随意性，减小了误差。     

西藏高原大地电磁深探测———亚东—巴木错沿线地区壳幔电性结构

摘 要　 展示了超宽频带大地电磁深探测所获得的西藏亚东—巴木错沿线地区电性结构图像; 阐述了西藏中、南部特殊的壳幔电性特征。     

一种地震数据多串口采集方法

地震监测系统常常使用串口异步通讯监测数据、传输命令,但由于核心器件所带的串口数量不足,通常需要扩展串口。提出以TL16C754B为核心器件的多串口数据采集方法,包括具体的系统电路的设计方法和部分驱动的编程源代码。由于该设计具有成本低、稳定性高、低耗、抗干扰能力强、电路简单等优点,已被成功地运用于微动台阵观测仪器中。     

草温、0cm地温、气温间变化规律分析

利用2008年信阳、郑州、南阳、商丘4个国家基本(准)站草温、0 cm地温和气温资料,分析了不同季节(冬、夏)、不同天气条件下草温、0 cm地温、气温的变化关系,结果表明:冬季无积雪和夏季的晴天,草温变化的振幅最大,位相靠前,0 cm地温居中,气温变幅最小;冬季有积雪时,0 cm地温在0 ℃左右变动,草温和气温表现出一定的变化幅度.从全年月平均值变化来看,0 cm地温>草温>气温;逐月极端最高值,0 cm地温>草温>气温;逐月极端最低值,草温＜0 cm地温＜气温.用草温比用0 cm地温和气温能更好地判定霜的出现.     

连续变脉宽发送激电方波与自动变周期测量二次场信号

介绍一种新的激电数据采集方式。该方式的主要特点在于一次测量操作可同时获取极化二次场随时间衰减和随深度变化的信息,同时还讨论了实现该采集方式的仪器工作原理和信号测量过程中的一些技术问题。     

三维全空间坑道直流聚焦超前探测数值模拟

应用同性点源之间的相斥和聚焦原理,设计出适合坑道空间的垂直聚焦超前探测方案。利用有限元法结合高效行压缩存储格式及迭代求解算法,对三维坑道空间中聚焦超前探测效果进行模拟研究。数值计算结果与土槽物理模拟实验结果对比,说明设计方案达到l了聚焦超前探测的目地。通过坑道复杂模型计算,表明垂直聚焦观测方案能够有效探测前方和旁侧存在的不良地质体。     

http://www.sciencedirect.com/science/article/pii/S1674987111001290

The Three Gorges Dam(TGD) of the Yangtze River.China,is one of the largest irrigation and hydroelectric engineering projects in the world.The effects of huge man-made projects like TGD on fauna and macrophyte are obvious,mainly through changes of water dynamics and flow pattern;however, it is less clear how microorganisms respond to such changes.This research was aimed to examine differences in microbial diversity at different seasons and locations(in front of and behind the TGD).In addition, differences between particle-attached and free-living communities were also examined.The community structures of total and potentially active microorganisms in the water columns behind and in front of the TGD were analyzed with the DNA- and RNA-based 16S rRNA gene phylogenetic approaches over three different seasons.Clone libraries of 16S rRNA genes were prepared after amplification from extracted DNA and.for some samples,after preparing cDNA from extracted rRNA.Differences were observed between sites at different seasons and between free-living and particle-attached communities.Both bacterial and archaeal communities were more diverse in summer than in winter, due to higher nutrient levels and warmer temperature in summer than in winter.Particle-attached microorganisms were more diverse than free-living communities,possibly because of higher nutrient levels and heterogeneous geochemical micro-environments in particles.Spatial variations in bacterial community structure were observed,i.e..the water reservoir behind the TGD(upstream) hosted more diverse bacterial populations than in front of the dam(downstream),because of diverse sources of sediments and waters from upstream to the reservoir.These results have important implications for our understanding of responses of microbial communities to environmental changes in river ecosystems affected by dam construction.