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海底表层沉积物具有多相、多颗粒、多形态的组成结构,导致其声学特性复杂多样。通过分析压缩波速度和切变波速度特性的研究现状,指出有待于解决的科学问题和关键技术问题。在分析国内外有关海底沉积层声速特性研究基础上,提出采取系统、可控的实验测量手段解决当前测量存在的4点问题。综合分析了压缩波速度和切变波速度存在的统计回归关系和理论分析关系,探讨了当前地声反演、采样样品声学测量、原位声学测量3种方法存在的测量尺度、测量频率、测量状态等的差异,探讨建立不同测量方法和测量技术对测量结果进行统一性解释的方法,从而获得不同类型、不同区域的海底表层沉积物真实的声速特性。最后,从实验室声学测量、物理力学参数测量、流固耦合特性分析、原位测量及海底监测、采样测量与原位测量的误差分析及校正、海底大纵深声学测量6个方面提出技术需求,为提高声学探测海洋和海底的精度服务,推动海洋声学探测和海洋工程发展。 相似文献
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金枪鱼是一种具备快速游泳能力的洄游性经济鱼类,其心血管系统存在血管逆流热交换器,并具备高心率、高心输出量、高血氧输送速率等特点。同时,作为区域恒温动物,金枪鱼对低温、低氧等环境有着独特的适应能力。为了系统地了解金枪鱼心血管系统的结构与功能特性及其环境适应性,本文综合国内外相关研究进展,阐述了金枪鱼独特的心血管系统组成与结构特点,分析了其高心输出量、高心率和高血氧输送速率的结构基础,并重点论述其支持高代谢率、调节体温、强低氧耐受能力等心血管功能,旨在为金枪鱼心血管系统方面的研究提供参考。 相似文献
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琼东南盆地陵南低凸起深水钻井岩心的稀土元素地球化学特征及其意义 总被引:2,自引:0,他引:2
A geochemical analysis of rare-earth elements(REEs) in 97 samples collected from the core of deep-water Well LS-A located at the Lingnan Low Uplift Area of the Qiongdongnan Basin is conducted, with the purpose of revealing the changes of sedimentary source and environment in the study region since Oligocene and evaluating the response of geochemical characteristics of REEs to the tectonic evolution. In the core samples, both ∑REE and ∑LREE(LREE is short for light-group REEs) fluctuate in a relatively wide range, while ∑HREE(HREE is short for heavy-group REEs) maintains a relatively stable level. With the stratigraphic chronology becoming newer, both ∑REE and ∑LREE show a gradually rising trend overall. The ∑REE of the core is relatively high from the bottom of Yacheng Formation(at a well depth of 4 207 m) to the top of Ledong Formation, and the REEs show partitioning characteristics of the enrichment of LREE, the stable content of HREE, and the negative anomaly of Eu to varying degrees. Overall the geochemical characteristics of REEs are relatively approximate to those of China's neritic sediments and loess, with significant "continental orientation". The ∑REE of the core is relatively low in the lower part of Yacheng Formation(at a well depth of 4 207–4 330 m), as shown by the REEs partitioning characteristics of the depletion of LREE, the relative enrichment of HREE, and the positive anomaly of Eu; the geochemical characteristics of REEs are approximate to those of oceanic crust and basalt overall, indicating that the provenance is primarily composed of volcanic eruption matters. As shown by the analyses based on sequence stratigraphy and mineralogy, the provenance in study region in the early Oligocene mainly resulted from the volcanic materials of the peripheral uplift areas; the continental margin materials from the north contributed only insignificantly; the provenance developed to a certain extent in the late Oligocene. Since the Miocene, the provenance has ceaselessly expanded from proximal to distal realm, embodying a characteristic of multi-source sedimentation. In the core strata with 31.5, 28.4, 25.5, 23, and 16 Ma from today, the geochemical parameters of REEs and Th/Sc ratio have significant saltation, embodying the tectonic movement events in the evolution of the Qiongdongnan Basin. In the tectonic evolution history of the South China Sea, the South China Sea Movement(34–25 Ma BP, early expansion of the South China Sea), Baiyun Movement(23 Ma BP), late expansion movement(23.5–16.5 Ma BP), expansion-settlement transition, and other important events are all clearly recorded by the geochemical characteristics of REEs in the core. 相似文献
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Chen Shangji 《海洋学报(英文版)》1993,12(3):359-377
The aim of this paper is to study whether the features of perennial summer over the South China Sea remain constant all the year round or not , and whether there are any seasonal differences throughout the year or not. According to the characteristics of remarkable monsoon and frequent typhoon, the influences of monsoon and tropical cyclone on the hydrological features and the seasonal structure over the South China Sea are analysed by using examples. It may be considered that in the perennial summer area over the South China Sea, it is summer all the year round, but it does not remain constant throughout the year. On the basis of index dates of developing stages for winter and summer monsoons as well as the seasonal characteristics of typhoon frequency,the perennial summer season over the South China Sea may be divided into four periods, namely, early summer, midsummer, sweltering summer and late summer. The concrete classification and the hydrological seasonal feature of each period are discussed. 相似文献
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产学研合作是促进海洋科技成果转化的重要措施.开展产学研合作应积极发挥产学研合作各方的优势.选择适当的合作模式.实现有效的产学研合作关键在于解决产学研合作的动力机制问题.以确保各方利益共享、风险共担.同时实现整体收益最大化的目标. 相似文献
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微塑料在海洋中的污染情况已经受到了人们广泛关注,但其与重金属相互作用产生的潜在生态风险依然需要进一步研究。本文主要综述了海洋中微塑料的来源及海水、沉积物和生物体内微塑料的污染现状,总结了部分海域微塑料上的重金属富集特征,并介绍了部分微塑料对重金属的吸附模型,最后总结分析了微塑料单独及与重金属协同作用对海洋生物的毒性效应。微塑料与重金属相互作用的结果依然存在许多不确定性,对生物体产生的毒性效应是协同、拮抗还是其他交互作用仍需更多的实验研究。本文旨在为评估微塑料与重金属相互作用造成的生态风险提供支撑,并为今后相关研究的开展提供参考。 相似文献
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利玛原甲藻(Prorocentrumlima,P.lima)是全球广泛分布的有害赤潮藻类,也是腹泻性贝毒(DiarrheticShellfish Toxins,DSTs)的主要产生藻之一,其产生的DSTs给海洋环境、渔业及人类健康带来了严重的危害。研究发现,全球范围内不同P.lima藻株的产毒能力具有显著差异,多种环境因子如营养盐、盐度、光照等因素均会对P.lima的产毒能力产生影响,从而决定了不同区域贝类中DSTs的风险。本文比较分析了全球范围内P.lima的产毒差异,并重点解析了环境因子对其产毒能力的影响,对于全球范围内P. lima产毒能力差异及影响因素形成了较为系统的科学认知,对未来开展P. lima海洋生态学及食品安全研究具有重要的借鉴意义。 相似文献