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保护窗口是深海视频采集系统的关键组件。为提高深海视频采集系统的整体性能,保障深海资源的勘探和开发利用,文章通过力学分析、理论对比和打压试验等过程,对保护窗口进行设计和优化。研究结果表明:球扇形窗口更适合全海深均匀高压环境;与主流窗口材料蓝宝石相比,我国自主研制的YAG透明陶瓷在性能和成本上具有优势;以第四强度理论作为充分准则进行设计,以第一和第二强度理论作为必要条件进行校验,结合有限元力学分析结果,外径为96mm的半球形保护窗口的最优内径为76mm;对采用该内径尺寸透明陶瓷保护窗口的深海视频采集系统进行全海深压强水下打压试验,有力证实相关理论和设计思想的合理性和可靠性。 相似文献
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Michael J. Cruickshank 《Marine Georesources & Geotechnology》2013,31(1):85-86
Abstract The engineering properties of deep continental margin sediments were determined on a worldwide basis. Deep Sea Drilling Project (DSDP) core data and material were utilized from over 900 cores obtained from 89 sites, primarily on the continental margins. Cores were recovered from penetrations to 200 m in water depths averaging 3000 m. Supplementary laboratory testing on selected cores was directed toward determining index properties and shear strength properties of the sediments. The study included a literature review of deep‐sea soil properties, the results of which are to be used by DSDP to evaluate foundation conditions for reentry cones with long casing strings. The results will also be used for a feasibility study of an ultradeepwater marine riser and well‐control system. The marine sediments examined can be divided into three main types: clay, calcareous ooze, and siliceous ooze. Sediment distribution consisted of 48% calcareous ooze, 43% clay, 6% siliceous ooze, and 3% volcanic ash. Because of the sample disturbance inherent in the deepwater coring operation, emphasis was placed on analyzing sediment properties not significantly affected by changes in in situ stresses and structure caused by sampling. Averages and ranges in values of water content and unit weight are presented for the three main sediment types. Plasticity and strength characteristics are discussed in detail and the elastic and compression properties are outlined. The geotechnical properties of deep continental margin soils are summarized. 相似文献
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利用25年(1993—2017)的卫星高度计资料, 采用复经验正交函数(complex empirical orthogonal function, CEOF)方法, 分析南海北部海区海面高度季节内变异的时空分布及传播特征。标准差分析表明, 南海北部海面高度的季节内变异(intra-seasonal variability of sea level anomalies, SLA-ISV)在沿陆坡外侧区较强, 且SLA-ISV表现出明显的季节性变化, 冬半年强于夏半年。CEOF前两个主要模态能较好地揭示研究海区SLA-ISV的时空分布及其传播特征, 并表明SLA-ISV的强度受到季节性变化和年际变化的调制。全年CEOF的第一模态揭示SLA-ISV从台湾岛西南至西沙群岛以东区域的冬半年西南向传播特征; 而全年CEOF的第二模态则表现了SLA-ISV分别在台湾岛西南和东沙群岛西南的西南向传播特征。南海北部中尺度涡季节变化统计分析表明, CEOF的分解结果与南海北部的涡旋活动一致。 相似文献
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Using observations and numerical simulations, this study examines the intraseasonal variability of the surface zonal current(u ISV) over the equatorial Indian Ocean, highlighting the seasonal and spatial differences, and the causes of the differences. Large-amplitude u ISV occurs in the eastern basin at around 80°–90°E and near the western boundary at 45°–55°E. In the eastern basin, the u ISV is mainly caused by the atmospheric intraseasonal oscillations(ISOs), which explains 91% of the standard... 相似文献
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对我国近年出现的几种新型码头结构的研究进行了综述和分析。其中,遮帘式板桩码头结构减小了作用于前板桩上的土压力,使板桩码头在大水深情况下得以应用;双排大管桩码头结构使大管桩较高的轴向承载力和抗弯强度得到充分发挥;架空直立式码头解决了内河大水位差情况下建造码头的难题;椭圆型沉箱的应用避免了采用2个圆沉箱产生前后不均匀沉降的技术难题。最后,对上述新型结构的应用进行了总结。 相似文献
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受大深度水体的影响,传统的海面拖曳式多道地震技术在进行深水地层探测时,目标地层深度处的菲涅耳半径非常大,水平分辨率低,难以满足海域天然气水合物高精度探测需求。针对海面拖曳式地震探测技术存在的上述问题,设计了一套可以在2000 m水深近海底作业的地震探测系统。应用耐压透声发射阵技术,克服了20 MPa外压环境和瞬时内压冲击对等离子体震源子波幅频特性的不利影响,研制的深拖等离子体震源的声源级达到214 dB,主频低于1000 Hz;水下控制中心采用集成SoC片上系统设计,可以对震源进行定距激发控制,进行近海底多道地震数据的连续采集。系统在2019年深海试验拖曳最大深度达2025 m,测试剖面数据显示最大地层穿透深度达380 m,纵向分辨率<2 m,横向分辨率<10 m,为深水海域沉积地层的深拖高分辨率地震探测提供了技术支撑。 相似文献
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利用1993~2017年海表面高度异常数据集,分析研究了西北太平洋季节内变化(20~120d)的整体分布特征,结果表明空间上季节内信号在20°N附近海域(16°~24°N)最强,时间上在6~8月达到一年中的最大值。在吕宋海峡东侧(123.875°E,20.125°N)季节内信号周期(70d)和传播速度(10.7~12.7cm/s)均大于吕宋海峡西侧(119.625°E, 20.125°N)(60 d, 6.5~7.8cm/s)。在大洋内部(123°~140°E, 18°~24°N)存在准90d的周期信号,传播速度约10.3cm/s。传播路径受黑潮的影响发生改变,由沿纬度西传转向向西北方向传播。第一斜压Rossby波理论对海表面高度季节内变化的周期和传播速度具有很好的解释性。 相似文献
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基于该系列文章前文研究中构建的海气耦合气候模式和所揭示的北大西洋热盐环流年代际振荡机制,针对海气要素对该振荡机制的影响问题进行了重点的探讨。为细致准确的研究北大西洋海洋要素同北大西洋热盐环流年代际振荡的关系,有针对性的定义了副极地海区表层密度指数和北大西洋暖流强度指数并对模式结果进行了全面分析。分析结果表明副极地海区表层密度变化领先大西洋径向翻转环流(MOC)变化7 a,北大西洋暖流的变化领先 MOC变化4 a,格陵兰－苏格兰海脊溢流水强度(包括丹麦海峡溢流水和法鲁海峡溢流水,是北大西洋深层水的重要来源)的变化领先 MOC的变化3 a;北大西洋大气要素变化对北大西洋热盐环流年代际振荡有非常重要的调制作用,当副极地流环和北大西洋暖流(NAC)达到最强的2 a之前,高纬度地区大气为气旋式环流异常,中纬度地区大气为反气旋式环流异常,海表热通量在大西洋副极地海区是负异常,这都有利于副极地流环和NAC的加强,更多高盐度的北大西洋水进入格陵兰-冰岛-挪威海(GIN)海域,由此可以导致GIN海域表层密度上升,使水体的层结稳定性减弱,有利于深层对流的发生,同时大气变化通过风应力旋度和海表热通量也直接影响GIN海域深层水的生成,进而导致格陵兰－苏格兰海脊溢流水的强度增加。 相似文献
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Ruijie Ye Feng Zhou Xiao Ma Dingyong Zeng Feilong Lin Hongliang Li Chenggang Liu Soe Moe Lwin Hlaing Swe Win Soe Pyae Aung 《海洋学报(英文版)》2023,42(2):83-93
Preparis Channel is the very important exchange path of energy and materials between the northern Bay of Bengal and Andaman Sea(AS). A set of hydrographic measurements, a microstructure profiler, and a deep mooring were used to determine the characteristics of water masses, turbulent mixing, and flows in the Preparis Channel. The unprecedented short-term mooring data reveal that a deep current in the deep narrow passage(below 400 m) of the Preparis Channel flows toward the Bay of Bengal(BoB) wit... 相似文献
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Shizuo Tsunogai Kentaro Kawada Shuichi Watanabe Takafumi Aramaki 《Journal of Oceanography》2003,59(5):685-693
The distributions of CFC (chlorofluorocarbon) in the water column was determined twice in 2000 and 2001 in the northwestern
Japan Sea. In 2000 the CFC-11 concentration decreased almost exponentially with depth from 6 pmol/kg at a few hundred m deep
to 0.3 pmol/kg or less at the bottom of about 3400 m depth at three stations (40–41°N, 132–133°E) about 300 km off Vladivostok.
In 2001 the CFC-11 concentration increased sharply up to 2 pmol/kg in the bottom water, while it did not increase at a station
(42.0°N, 136.5°E) about 450 km away to the northeast. This is due to the renewal of the bottom water which is replaced by
the surface water flowing down along the continental slope, as suggested by Tsunogai et al. (1999), who proposed the continental shelf pump. Furthermore, an increase in the CFC-11 concentration was observed throughout
the entire water column above 3000 m depth, although the proportion of the increase was about 20%, which was one order of
magnitude smaller than that in the bottom water. The increase in inventory is almost four times larger than that in the bottom
water below 3000 m depth which is equivalent to about 1/6 of the total inventory found in 2000. The increase also means that
3% of the deep water was replaced by the recent surface water, or, if the turnover occurs every year, that the turnover time
of the deep water to be about 30 years.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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A coupled ocean-ice-wave model is used to study ice-edge jet and eddy genesis during surface gravity wave dissipation in a frazil-pancake ice zone. With observational data from the Beaufort Sea, possible wave dissipation processes are evaluated using sensitivity experiments. As wave energy dissipated, energy was transferred into ice floe through radiation stress. Later, energy was in turn transferred into current through ocean-ice interfacial stress. Since most of the wave energy is dissipated at the ice edge, ice-edge jets, which contained strong horizontal shear, appeared both in the ice zone and the ocean. Meanwhile, the wave propagation direction determines the velocity partition in the along-ice-edge and cross-ice-edge directions, which in turn determines the strength of the along-ice-edge jet and cross-ice-edge velocity. The momentum applied in the along-ice-edge(cross-ice-edge)direction increased(decreased) with larger incident angle, which is favorable condition for producing stronger mesoscale eddies, vice versa. The dissipation rate increases(decreases) with larger(smaller) wavenumber, which enhances(reduces) the jet strength and the strength of the mesoscale eddy. The strong along-ice-edge jet may extend to a deep layer(> 200 m). If the water depth is too shallow(e.g., 80 m), the jet may be largely dampened by bottom drag, and no visible mesoscale eddies are found. The results suggest that the bathymetry and incident wavenumber(magnitude and propagation direction) are important for wave-driven current and mesoscale eddy genesis. 相似文献
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Angus I. Best William Powrie Toby Hayward Max Barton 《Marine Georesources & Geotechnology》2013,31(4):315-331
Abstract Recent marine forensic investigations have largely unravelled the sequence of events concerning the sinking of the R.M.S. Titanic and its descent through nearly 3800 m of water to the seafloor on the morning of 15 April 1912. In particular, the velocity and attitude of the Titanic's bow section (at present lying upright, reasonably intact, and embedded by ～12 m at the prow) as it hit the bottom are of general interest to marine accident investigators. During the 1998 Titanic Science Expedition, a single sediment sample was retrieved from the seafloor (depth 20–30 cm) near the wreck by the deep water submersible, Nautile. Published geological studies suggest the seafloor in this area has remained largely undisturbed since 1912. Geotechnical analysis of the sediment sample reveals that the impact was probably a substantially undrained event and that the characteristic undrained shear strength of the sediment is ～25kPa within 10–16 m below the seafloor. A simple analytical model was used to calculate the embedment of a cuboid with dimensions and mass of the water-filled bow as a function of impact velocity, impact angle, and the undrained shear strength of the sediment. The results indicate the impossibility of a steep angle of impact and fast velocity. The most likely scenario is an impact velocity of 5–10 m/s at a fairly shallow angle (<40°), which corroborates the results of hydrodynamic investigations. 相似文献
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Shanwei Ke Peng Wang Xueyue Geng Jun Hai Jinqiang Jin 《Marine Georesources & Geotechnology》2020,38(8):970-979
AbstractCompared with traditional vacuum preloading, air booster vacuum preloading is more effective at strengthening dredged slurry and improving the consolidation process. Although many engineering practices have shown that the pressurized duration has a significant effect on the reinforcement effect, there is no standard available for determining the pressurized duration. In this study, five dredged slurry samples were tested to examine the effect of different pressurized durations on the consolidation. An extensive monitoring system was used to measure the vacuum pressure, pore water pressure, settlement, and water discharge during the test, while the water content and shear strength were measured after the test. The collected monitoring data were comprehensively analyzed to evaluate the reinforcement effect. The results revealed that the pressurization system can be used to reinforce deep dredged slurry and make the whole soil layer more homogeneous. If the pressurized duration is too short, the dissipation of pore water pressure is too little to achieve the pressurization effect. If the pressurized duration is too long, too much gas will be in the soil and enter the vacuum system, which will significantly reduce the vacuum pressure and thus the reinforcement effect. Based on these findings, the optimal pressurized duration was obtained. 相似文献
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Severe hypoxia was observed in the submarine canyon to the east of the Changjiang estuary in July 14, 2015, two days after typhoon Chan-hom. The oxygen concentration reached as low as 2.0 mg/L and occupied a water column of about 25 m. A ROMS model was con?gured to explore the underlying physical processes causing the formation of hypoxia. Chan-hom passed through the Changjiang estuary during the neap tide. The strati?cation was completely destroyed in the shallow nearshore region when typhoon passing. However, it was maintained in the deep canyon, though the surface mixed layer was largely deepened. The residual water in the deep canyon is considered to be the possible source of the later hypoxia. After Chan-hom departure, not only the low salinity plume water spread further of fshore, but also the sea surface temperature(SST) rewarmed quickly. Both changes helped strengthen the strati?cation and facilitate the formation of hypoxia. It was found that the surface heat ?ux, especially the solar short wave radiation dominated the surface re-warming, the of fshore advection of the warmer Changjiang Diluted Water(CDW) also played a role. In addition to the residual water in the deep canyon, the Taiwan Warm Current(TWC) was found to ?ow into the deep canyon pre-and soon post-Chan-hom, which was considered to be the original source of the hypoxia water. 相似文献
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本文使用加拿大气候模拟与分析中心(Canadian Center for Climate Modeling and Analysis,CCCma)的耦合模式预报产品,应用以信息论为基础的可预报性理论框架,诊断、分析了耦合模式中Madden-Julian Oscillation(MJO)的预报率,包括实际预报技巧和潜在预报率,以及热带季节内尺度变率(Intraseasonal Variability,ISV)最可预报模态的空间分布。并在此基础上讨论了不同时间尺度平均对MJO预报技巧的影响。结果表明:本文使用的2个耦合模式中,MJO的预报技巧与目前全球主要使用的预报模式相近,约为10 d。潜在可预报技巧可以达到30 d以上。随着时间尺度从日平均增加到10 d平均,MJO的实际预报技巧与潜在可预报技巧都相应提高,尤其是潜在可预报技巧的提高更加显著。进一步分析发现,影响实际预报技巧的一个重要因素是初始条件MJO信号的强弱,当MJO信号很强时,预报技巧较高,反之则较低。本文最后分析了模式中ISV最可预报模态的空间分布,并讨论了如何利用这种最可预报空间分布提高ISV的实际预报技巧。 相似文献
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为适应中国南海深水区域的油气田开发,研发出了一种具有渐变式立柱的深吃水干树式半潜钻井/生产平台(TCDDSemi)。平台的浮体采用了深吃水、变截面长立柱构型,即向底部逐渐扩大的渐变截面形式。结合干树式深吃水半潜平台的研发过程,通过采用压缩空气压载系统、全注水下浮体、压缩空气水密检测以及水密面板的三级正交加强筋设计等新兴技术,极大地提高了钢材的利用效率,达到了节省材料、减轻浮体自重的目的。对浮体的有限元(FEM)整体分析结果表明,浮体结构设计满足各工况强度要求。 相似文献
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根据1979,1996和2009年3个时期水深地形数据,利用GIS软件分析了岱山水道西部潮滩、水下岸坡和深槽区2个时段的冲淤变化。结果显示:1979-1996年的17 a间,研究区大部分区域冲淤幅度-般在±1 m以内,只有深槽局部区域冲刷大于2 m;1996-2009年的13 a间,潮滩区冲淤变化与1979-1996年间类似,有±1 m冲淤变化,而水下岸坡和深槽区的冲刷幅度明显加大,水下岸坡平均冲刷幅度达2 m,深槽区平均冲刷幅度达3 m。据分析, 1996年以后,水下岸坡和深槽区冲刷幅度明显加大的主要原因有两个:-是岱山水道水流流速较快,粘土质的底质容易遭受冲刷;另-个是在潮滩区至水下岸坡间建设了码头和栈桥,浅水区水流部分受阻,导致深水区域流速加大,从而加剧了水下岸坡和深槽区域的冲刷幅度。 相似文献