In situ velocity profiles in gassy sediments: Kiel Bay

Acoustic behavior of gas-bearing sediments is significantly different from that of gas-free sediments. In situ velocity profiles and acoustic signal characteristics in gas-bearing sediments of the upper several meters of the sea floor in Kiel Bay are presented in this study. Observed velocities in gas-bearing sediments are both higher and lower than those of the gas-free sediments. Small amounts of gas appear to cause signal reverberation without much attenuation. whereas large amounts of gas cause substantial attenuation.     

沉积物粒度参数的无偏估计及其在长乐海岸的应用

根据数理统计方法对粒度参数进行无偏估计,使之较以往参数估计更符合无系统误差的这一估计量的评选标准,并用这一方法对长乐东部海岸的风沙进行了系统的粒度参数分析,结果表明长乐海岸风沙沉积物的主要粒级为细沙,分选好,偏度为近对称,峰态很窄等特征,说明研究区域海岸风沙的搬运风动力主要为NE向、而且动力强度较稳定。     

The evolution of the coral reefs in the middle and north parts of the South China Sea and its relation with tectonic and eustatic movements

In this paper, the morphogenesis, stratigraphic sequences and dates of the coral reefs in the middle and north parts of the South China Sea are discussed, the position of the distributary regions of Cenozoic coral reefs in plate tectonics, the relationships of coral-reef evolutionary characteristics and dates with sea-basin spreading. Neogene sea-water transgression and Quaternary global climate-eustatic fluctuation are expounded and proved, and the latitudinal variation of the distribution of coral reefs in various geologic times are summed up.     

Gradation affects basic mechanical characteristics of Chinese calcareous sand as airport subgrade of reefs

Abstract

Construction of the reefs in the South China Sea is a significant foundation to the secure stability and economic development of China. The construction of an airport runway is necessary for this realization. The calcareous sand is the main primary material in the runway construction. A certain type of calcareous sand near a certain reef of the South China Sea was studied in this paper. To investigate this specific calcareous sand, quartz sand was used as a reference for comparison. Microscopic 3-D imaging, compression and triaxial tests were conducted to test the micro, squeezing and shear properties. The effect mechanism of gradation on the calcareous sand’s compressibility and shear characteristics are discussed from a mesoscopic viewpoint using 3-D morphology. Calcareous sand particles are multiangular and flatter in comparison with quartz sand. The larger the particle sizes are, the more different the two sands’ morphologies are. The compressibility of calcareous sand is greater, and the effect of the coarse fraction (5–1?mm) content in the gradation plays the most significant role in this feature. When the coarse particles’ content is less than 25% and the mass ratio of the middle and fine particles (M) is constant, there is the worst coarse fraction content causing the calcareous sand to be most likely compressed. The worst coarse fraction content decreases with the increase in M, and an empirical formula is proposed. When the gradation, relative density and confining pressure are the same, the peak shear stress and strain of calcareous sand are all at a high level. The effect of confining pressure is manifested in calcareous sand. The shear strength and dilation of calcareous sand are also most affected by the medium coarse fraction (5–0.25?mm) content.     

A fuzzy approach to the lectotype optimization of offshore platforms

Lectotype optimization of offshore platforms is of particular importance in the concept design process. Lectotype optimization involves multiple objectives with uncertainty and so is a problem of multiple attribute decision making. To date, there have been few published works on this topic in the context of offshore engineering. This paper develops a framework and methodology for evaluation of offshore platform alternatives, where a fuzzy optimum model is proposed to integrate the influence of each objective in the criteria set, and a new weight-assessing method is developed to mimic the decision maker’s experience and preference based on complementary pairwise comparisons. A case study shows that the new framework and methodology is scientific, reasonable and easy to use in practice.     

生物胺对锯缘青蟹大颚器发育的调节作用

雌性锯缘青蟹(Scylla serrata)于实验的第1天、第5天、第10天，分别注射100μL剂量为1μg／g体质量的5-HT，OA和DA，第15天解剖。结果表明，5-HT对锯缘青蟹大颚器发育具有显的促进作用，OA和DA的作用不明显。经免疫细胞化学检测，大颚器内存在5-HT免疫阳性细胞，免疫阳性细胞多数为卵圆形，少数具有很长的胞突，该结果首次为5-HT参与大颚器的生理活动提供了形态学证据。     

潮汐测量与验潮技术的发展

潮汐是由各天体作用于地球上的引潮力所产生，不仅海洋中有潮汐，大气圈和地球固体部分也同样存在着潮汐。海道测量中的潮汐测量仅指海洋潮汐测量仅指海洋潮汐测量，潮汐测量的手段很多，主要包括采用水尺；浮子式、引压钟式、声学式、压力式验潮仪验潮。而GPS验潮及潮汐遥感测量等技术研究国内外正在开展。所有这些验潮技术各有自己的特点。     

A Unified Variational Principle of Fluid Mechanics and Application on Solitary Subdomain or Point

-According to basic equations of fluid mechanics, this paper presents a unified variational principle of fluid mechanics (UVPFM) by using the optimization method of weighted residuals (OMWR). The advantages are as follows, the establishment of the functional and the variational principle is easy, it can change various problems of fluid mechanics derived by basic equations into a unified optimization problem, and the solution is the optimum one in some sense. According to the OMWR for the solitary subdomain, this paper uses UVPFM onto any solitary subdomain and gives the solution of the hydrodynamics equation which is suitable only for that solitary subdomain. According to the OMWR for solitary point, this paper uses UVPFM to any solitary point and gives the solution of the hydrodynamics equation (point solution) which is suitable only for that solitary point. As the solution for the solitary subdomain or solitary point is developed independently, the compatibility with other subdomain or other points, do     

厦门海沧海岸地区采石废弃地生态恢复研究

本文分析了厦门海沧海岸地区花岗岩资源开发利用现状和存在的问题，运用生态恢复理论讨论了矿山采石高难度地生态恢复技术途径和模式。     

南沙群岛海区冬夏季中、深层海流的计算

根据１９８８年夏季和１９８９年冬季南沙群岛海区两个航次的温、盐度调查资料，运用β螺旋方法对调查海区的海流进行了计算。计算结果表明，该海区表、中层环流相对比较一致，深层流动状态与表、中层的差异较大，其中的局地环流的季节变化不明显。此外，在北康暗沙与南薇滩之间，夏季中、深层和冬季深层都明显反映出存在着一个迄今未见报道的局地反气旋式环流。文章对上述结果与该海区已有的一些海流分析结果作了比较。