The Optimal Design of TMD for Offshore Structures

This paper presents the optimal design procedure of Tuned Mass Damper(TMD)for re-ducing vibration of an actual steel jacket offshore platform excited by random wave loading.In this study,a frequency domain is taken.The force on the structure is determined by use of the linearized Morisonequation for an input Power Spectral Density(PSD)of wave elevation.The sensitivity of optimum valuesof TMD to characteristic parameters of random wave spectrum is analyzed.An optimized TMD designfor the modeled platform is given based on design conditions and the findings of the study.     

南海东北部海陆深地震联测与滨海断裂带两侧地壳结构分析

南海东北部首次成功实施海陆联合深地震探测,填补了海陆过渡带深地震探测的空白. 利用该次海陆联测地震数据,通过数据处理、震相分析、射线追踪、走时模拟等方法,获得了滨海断裂带附近的纵波地壳速度结构,探明了海陆联测剖面中滨海断裂带可能位置. 地壳速度结构为陆壳结构,地壳厚度由陆地向海区逐步变薄;在上地壳下部普遍存在一层速度为5.5～5.9km·s-1、厚度为2.5～4.0km的低速层,并向海区方向减薄,该区未发现明显的高速层. 滨海断裂带为一纵向低速带,位于南澳台东南35km处,对应于重、磁异常带,断裂带断至莫霍面,是华南陆区正常型陆壳与海区减薄型陆壳的分界地壳断裂.     

Meso-scale circulation at the intermediate-depth east of Mindanao observed by Argo profiling floats

The meso-scale circulation at the intermediate depth east of Mindanao is studied using Argo profiling floats observations. The trajectories and the parking-depth velocities of Argo floats show that the intermediate-depth circulation east of Mindanao contains significant meso-scale features that are highly variable both in space and in time. Both cyclonic and anticyclonic eddies at the intermediate depth (1000–2000 m) are indicated by the trajectories east of Mindanao. The mean tangential velocities of these eddies are about 10 cm/s at 2000 m and over 20 cm/s at 1000 m, which indicates that the geostrophic calculation may contain large errors due to the vigorous eddy activity at the reference levels. The analyses also suggest that these eddies might play an important role in mass and vorticity balances of the intermediate-depth circulation east of Mindanao.     

Heavy mineral stratigraphy of sediments from the southern outer shelf of the East China Sea since the last glaciation using fuzzy C-means cluster method

Correspondence analysis and fuzzy C-means cluster methods were used to divide the stratigraphy of heavy mineral assemblages,and the sediment sources and depositional dynamics of the environment reconstructed.The assemblages were taken from marine sediments from the late Pleistocene to the Holocene in Core Q43 situated on the outer shelf of the East China Sea.Based on the variable boundaries of the mineral assemblage at 63 and 228 cmbsf (cm below sea floor),the core might have previously been divided into th...     

Anti-proliferative activity of phlorotannin extracts from brown algae Laminaria japonica Aresch

In this study,we evaluated the anti-proliferative activity of phlorotannins derived from brown algae Laminaria japonica Aresch extracts on the human hepatocellular carcinoma cell (BEL-7402) and on murine leukemic cells (P388) by MTT assay.Cells were incubated with 100 μg/mL of the phlorotannin extract (PE) for 48 h.The inhibitory rate of PE on BEL-7402 and P388 cells was 30.20±1.16% and 43.44±1.86%,respectively,and the half-inhibitory concentration of PE (IC50) on P388 and BEL-7402 cells was 120 μg/mL and >...     

Tectonics and Mechanisms of Uplift in the Central Uplift Belt of the Huimin Depression

The Huimin (惠民) depression is a third-level tectonic element of the Bohai (渤海) Bay basin in eastern China. The central uplift belt is the most important oil and gas accumulation zone in the depression, but the lack of adequate geological studies in the area has greatly hindered exploration and development. In this article, using seismic data, fracture mechanics, and a combination of data on fault growth indices and fault throws, we present an analysis of tectonic activity in the central uplift belt and adja...     

Effect of nitrogen to phosphorus ratios on cell proliferation in marine micro algae

The ratio of nitrogen/phosphorus (N/P) is known to affect cell proliferation of some marine micro algae. We evaluated the effect of N/P ratios on the proliferation and succession of phytoplankton using five marine micro algae species. We used two sources of nitrogen, NH4Cl (N1) and urea (N2), and a single source of phosphorous, NaH2PO4(P). The optimal N/P ratio that differed among the five species was affected by the source of nitrogen, being as follows (N1/P, N2/P in order): Thalassiosira sp. (30/1, 20/1),...     

热带西太平洋海域上层海洋热含量的CSEOF分析

基于月平均Argo温、盐度剖面、纬向风和Ni o3.4指数等资料,利用循环平稳经验正交函数(CSEOF)分解法、最大熵谱分析和相关分析等方法,研究了热带西太平洋海域上层(0—700m)海洋热含量的时空变化特征,并探讨了其年际变化的可能原因。结果表明,热带西太平洋海域上层海洋热含量距平场具有显著的东-西向反位相振荡,且这种振荡除了具有较明显的季节变化外,还存在着较强的准2a振荡。此外,热含量距平场还存在着负-正-负的三极式经向模态,该模态除了具有明显的季节变化外,还存在着显著的准4a振荡。进一步分析表明,热含量的准2a振荡与ENSO事件的发生有着非常密切的联系,并对赤道西太平洋纬向风异常有1—2月的滞后响应。     

末次冰消期以来东海内陆架沉积速率及其气候环境响应

对位于东海内陆架浙-闽沿岸泥质带的EC2005孔岩性、粒度以及AMS14C年代进行了分析,着重探讨了研究区自末次冰消期以来的沉积速率变化,划分出4个大的沉积阶段和4次快速沉积事件.千年时间尺度上大的沉积阶段主要受控于物源供应、海平面变化以及可容空间的大小.百年时间尺度上揭示的4次快速沉积事件主要受控于东亚冬季风的增强或...     

峨眉山玄武岩的地幔热柱成因

根据峨眉山玄武岩的岩石组合、岩相学特征将峨眉火成岩省分为盐源-丽江岩区、攀西岩区、贵州高原岩区和松潘-甘孜岩区。通过对研究区二叠世的区域地质背景和古地理环境的分析，对峨眉山玄武岩喷发与地幔热柱的关系及其火山喷发的大地构造背景进行了进一步系统归纳和总结。根据地层学关系大致确定峨眉山玄武岩的主喷发期是阳新世（中二叠）晚期-乐平世（晚二叠）早期，时限大致为259Ma-257Ma。峨眉山玄武岩微量元素地幔标准化曲线特征与OIB基本一致，反映出其成因与地幔热柱活动有密不可分的关系。