Experimental Study on A Sloshing Mitigation Concept Using Floating Layers of Solid Foam Elements

A sloshing mitigation concept taking advantage of floating layers of solid foam elements is proposed in the present study. Physical experiments are carried out in a liquid tank to investigate the hydrodynamic mechanism of this concept. Effects of the foam-layer thickness, excitation amplitude, and excitation frequency on the sloshing properties are analyzed in detail. It is found that the floating layers of solid foam elements do not evidently affect the fundamental natural sloshing frequency of the liquid tank evidently among the considered cases. At the resonant condition, the maximum wave height and dynamic pressure are greatly reduced as the foam-layer thickness increases. Higher-order pressure components on the tank side gradually vanish with the increase of the foam-layer thickness. Cases with different excitation amplitudes are also analyzed. The phenomenon is observed when the wave breaking in the tank can be suppressed by solid foam elements.     

近千年来台湾以东黑潮主流区沉积物来源及其对气候波动的响应

基于AMS¹⁴C定年结果,对近千年来台湾以东黑潮主流区沉积物的粒度、黏土矿物组成及结晶学特征等进行研究,分析该区沉积特征、物质来源及近千年来环境演化的沉积记录。结果表明,台湾以东黑潮主流区沉积物主要为细粒的粉砂和黏土,沉积速率平均为34.44 cm/ka,低于东海陆架和冲绳海槽南部,高于开阔大洋,具有从陆架向大洋过渡的沉积特征。黏土矿物组成的分析结果表明,台湾以东黑潮主流区沉积物黏土矿物组成以伊利石(平均57%)和蒙脱石(平均25%)为主,含有少量绿泥石(平均16%),几乎不含高岭石(平均2%),其中蒙脱石主要来源于吕宋岛弧物质输送和附近海域原位的基性火山物质蚀变,伊利石和绿泥石主要来源于亚洲大陆风尘输送和台湾东部河流输入,高岭石主要来源于台湾东部河流和吕宋岛弧物质输入。黏土矿物的物源定量识别研究表明,研究站位的黏土矿物有26%～72%来源于亚洲大陆风尘输送,11%～55%来源于台湾东部河流输入,11%～26%来源于吕宋岛弧物质输送。近千年来沉积物物源的变化特征较好地反映了中世纪暖期、小冰期和现代暖期这3个百年尺度的全球性气候变化阶段。亚洲大陆风尘输送和台湾东部河流输入对研究区沉积物的相对贡献量变化反映了中世纪暖期较强的东亚冬季风特征和台湾地区较为干旱的气候环境,同时也反映了小冰期逐渐减弱的东亚冬季风强度和台湾地区较为湿润的气候环境。现代暖期和中世纪暖期在东亚热力差异和降水异常上的差别反映了人类活动对沉积物的扰动。而研究区小规模的沉积特征突变事件主要与暴雨、台风和地震活动相关。     

文本地理编码关键技术研究与分析

随着互联网应用的发展,所产生的非结构化文本大多与地理位置相关联,因此,地理信息检索(GIR)成为当前GIS和IR领域研究的热点。文本地理编码是建立文本与地理位置坐标对应关系的过程,是实现GIR的基础。本文对文本地理编码涉及的地理实体识别、地理实体消歧、文本位置聚焦、区域语言建模等关键技术进行分类总结,提出了该领域未来研究工作和面临的挑战,为文本地理编码进一步相关研究提供新思路。     

AR模型中AO类异常值探测及其在GPS卫星钟差预报中的应用

基于EM算法,提出一种AR模型中AO类异常值(additive outlier)探测的算法。该算法可同时进行AR模型拟合与AO类异常值探测,并可有效地解决成片AO类异常值探测时所产生的掩盖和淹没问题。最后,将本文算法应用于GPS卫星钟差预报之中。本文算法可以准确探测出钟差历史观测序列中的AO类异常值,并可对卫星钟差进行精确预报。     

Functional characterization of a Δ6 fatty acid desaturase gene and its 5′-upstream region cloned from the arachidonic acidrich microalga Myrmecia incisa Reisigl (Chlorophyta)

Journal of Oceanology and Limnology - It is suggested that Δ6 fatty acid desaturase (FAD) plays a critical role in the biosynthesis of polyunsaturated fatty acids in plants and microalgae. But...     

Analysis of Buoyancy Module Auxiliary Installation Technology Based on Numerical Simulation

To reduce the requirement for lifting capacity and decrease the hoist cable force during the descending and laying process of a subsea production system (SPS), a buoyancy module auxiliary installation technology was proposed by loading buoyancy modules on the SPS to reduce the lifting weight. Two models are established, namely, the SPS lowering-down model and the buoyancy module floating-up model. The main study results are the following: 1) When the buoyancy module enters the water under wave condition, the amplitude of tension fluctuation is twice that when SPS enters water; 2) Under current condition, the displacement of SPS becomes three times larger because of the existence of the buoyancy module; 3) After being released, the velocity of the buoyancy module increases to a large speed rapidly and then reaches a balancing speed gradually. The buoyancy module floats up at a balancing speed and rushes out from the water at a pop-up distance; 4) In deep water, the floating-up velocity of the buoyancy module is related to its mass density and shape, and it is not related to water depth; 5) A drag parachute can reduce floating-up velocity and pop-up distance effectively. Good agreement was found between the simulation and experiment results.     

BP神经网络精度估计及其在海洋油气资源预测中的应用

在对BP算法进行深入分析的基础上,将测量数据处理与误差理论中的精度评定方法应用到BP神经网络的精度估计中,通过分别计算BP神经网络学习训练过程及预测过程的输出层中误差,实现对神经网络模型的精度评定。最后以海洋油气资源预测为例,结合实测资料建立了BP神经网络预测模型并分别进行了学习训练过程及预测过程的精度评定,以期为神经网络模型结构的优化设计提供有效参考,为提高神经网络模型的适用性提供科学依据。     

中国海域海盘车科(棘皮动物门,海星纲)种类记述

基于中国科学院海洋生物标本馆的馆藏标本,通过传统形态学,结合扫描电子显微镜等方法,对分布于中国海域的海盘车科(Asteriidae)种类进行了系统的分类学研究,共鉴定出该科5属10种,分别为:粗钝海盘车(Asterias argonauta Djakonov, 1950)、多棘海盘车(Asterias amurensis Lütken, 1871)、罗氏海盘车(Asterias rollestoni Bell, 1881)、异色海盘车(Asterias versicolor Sladen, 1889)、日本滑海盘车(Aphelasterias japonica (Bell, 1881))、张氏滑海盘车(Aphelasterias changfengyingi Baranova Wu, 1962)、日本长腕海盘车(Distolasterias nipon(D?derlein,1902))、美丽长腕海盘车(Distolasterias elegans Djakonov,1931)、座冠海星[Coronaster volsellatus(Sladen,1889)]和尖棘筛海盘车[Coscinasterias acutispina(Stimpson,1862)]。文中对物种的鉴别特征进行了描述,并提供了地理分布和种属鉴定所需要的检索表。     

礼乐盆地碳酸盐岩时空分布特征及构造意义

对碳酸盐岩(台地与生物礁)的研究具有重要的油气地质意义和科学价值。渐新世以来, 礼乐盆地及周缘开始了大规模的碳酸盐建造, 至今还有一定规模生物礁持续发育。文章通过拖网约束、井震对比和地震相类比方法对礼乐盆地周缘碳酸盐岩的发育特征、构造背景和时空分布规律进行系统研究。结果表明, 礼乐盆地主要发育孤立、前隆、掀斜断块型台地及生物礁。碳酸盐岩时空发育特征为: 1) 渐新世—早中新世以构造前隆和掀斜断块控制的开阔台地为主, 生物礁零星发育; 2) 早中新世—中中新世表现为大量孤立台地和生物礁; 3) 中中新世之后, 发生台地和礁的淹没, 盆地内主要发育点礁。结合构造背景和重磁特征分析表明, 古隆起、掀斜断块、前隆迁移和岩浆活动为控制礼乐盆地不同时期碳酸盐岩发育的主要构造要素。现今礼乐盆地及周缘大量生长的珊瑚礁, 主要发育在上新世—更新世岩浆活动形成的海山之上。     

A statistical study towards high-mass BGPS clumps with the MALT90 survey

In this work,we perform a statistical investigation towards 50 high-mass clumps using data from the Bolocam Galactic Plane Survey(BGPS)and Millimetre Astronomy Legacy Team 90-GHz survey(MALT90).Eleven dense molecular lines(N_2H~+(1–0),HNC(1–0),HCO~+(1–0),HCN(1–0),HN~(13)C(1–0),H~(13)CO~+(1–0),C_2H(1–0),HC_3N(10–9),SiO(2–1),~(13)CS(2–1)and HNCO(4_(4,0)-3_(0,3)))are detected.N_2H~+ and HNC are shown to be good tracers for clumps in various evolutionary stages since they are detected in all the fields.The detection rates of N-bearing molecules decrease as the clumps evolve,but those of O-bearing species increase with evolution.Furthermore,the abundance ratios[N_2H~+]/[HCO~+]and log([HC_3N]/[HCO~+])decline with log([HCO~+])as two linear functions,respectively.This suggests that N~+2H~+ and HC_3N transform to HCOas the clumps evolve.We also find that C_2H is the most abundant molecule with an order of magnitude 10~(-8).In addition,three new infall candidates,G010.214–00.324,G011.121–00.128 and G012.215–00.118(a),are discovered to have large-scale infall motions and infall rates with an order of magnitude 10~(-3)M_⊙yr~(-1).