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The scattering problem involving water waves by small undulation on the porous ocean-bed in a two-layer fluid,is investigated within the framework of the two-dimensional linear water wave theory where the upper layer is covered by a thin uniform sheet of ice modeled as a thin elastic plate.In such a two-layer fluid there exist waves with two different modes,one with a lower wave number propagate along the ice-cover whilst those with a higher wave number propagate along the interface.An incident wave of a particular wave number gets reflected and transmitted over the bottom undulation into waves of both modes.Perturbation analysis in conjunction with the Fourier transform technique is used to derive the first-order corrections of reflection and transmission coefficients for both the modes due to incident waves of two different modes.One special type of bottom topography is considered as an example to evaluate the related coefficients in detail.These coefficients are depicted in graphical forms to demonstrate the transformation of wave energy between the two modes and also to illustrate the effects of the ice sheet and the porosity of the undulating bed. 相似文献
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学习贯彻十七大精神,对于动员拿党全国各族人民,存以胡锦涛同忠为总书记的党中央坚强领导下,高举中国特色社会主义伟大旗帜,奋力夺取全面建没小埭社会新胜利、圩创中国特色礼会主义事业新局而,具有重大现实意义和深远历史意义。长汀航道各级党组织要把组织学习和贯彻落实十七大精神作为当前和今后一个时期的首要政治任务,迅速把干部职工的思想和行动统一到全会精神上来, 相似文献
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<正>众所周知,三一重工股份有限公司是一家享有盛誉的上市公司,曾连续4年上榜中国最具价值品牌,是工程机械行业内的标志性企业之一。作为中国最具科研实力的工程机械制造商,三一重工拥有国家级技术中心、博士后工作站,并承接有国家863课题,取得专利400多项。三一重 相似文献
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0引言近年来全球集装箱运量的年增长率基本维持在10%以上,据初步统计2007年全球集装箱运量达1.3亿TEU,港口吞吐量达4.7亿TEU。随着集装箱制造、装卸工艺的改进,适箱货物的范围也在不断扩大。20世纪90年代,美国就开始采用集装箱运 相似文献
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美国海岸警备队港口长官(COTP)或口岸当局(OCMI)对存在缺陷的船舶,根据缺陷的严重性,决定对这些船舶采取控制行动来保证船舶、港口和环境的安全,至于控制的程度、范围以及当局的执行力则和这些缺陷的本性一致. 相似文献
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Global strength is a significant item for floatingproduction storage and offloading (FPSO) design, and steel weightplays an important role in the building costs of FPSO. It is the maintask to consider and combine these two aspects by optimizing hulldimensions. There are many optional methods for the globalstrength analysis. A common method is to use the ABS FPSOEagle software to analyze the global strength including the rulecheck and direct strength analysis. And the same method can beadopted for the FPSO hull optimization by changing the depth.After calculation and optimization, the results are compared andanalyzed. The results can be used as a reference for the futuredesign or quotation purpose. 相似文献
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由丹丹;孙丽萍;曲治国;王涛 《船舶与海洋工程学报》2013,12(4):459-462
For a large floating vessel in waves,radiation damping is not an accurate prediction of the degree of roll unlike other degrees of freedom motion.Therefore,to get the knowledge of roll motion performance of deepwater pipelay crane vessels and to keep the vessel working safety,the paper presents the relationship between a series of dimensionless roll damping coefficients and the roll response amplitude operator(RAO).By using two kinds of empirical data,the roll damping is estimated in the calculation flow.After getting the roll damping coefficient from the model test,a prediction of roll motion in regular waves is evaluated.According to the wave condition in the working region,short term statistics of roll motion are presented under different wave parameters.Moreover,the relationship between the maximal roll response level to peak spectral wave period and the roll damping coefficient is investigated.Results may provide some reference to design and improve this kind of vessel. 相似文献
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This paper discusses the numerical modeling of the dynamic coupled analysis of the floating platform and mooring/risers using the asynchronous coupling algorithm with the purpose to improve the computational efficiency when multiple lines are connected to the platform. The numerical model of the platform motion simulation in wave is presented. Additionally, how the asynchronous coupling algorithm is implemented during the dynamic coupling analysis is introduced. Through a comparison of the numerical results of our developed model with commercial software for a SPAR platform, the developed numerical model is checked and validated. 相似文献
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玻璃瓶砸过来时,37岁的轮机长杨长德(化名)脑子里只来得及闪过一个念头——死定了。杨长德是广东驳运公司(下称广东驳运)的员工。10月11日凌晨,广东驳运1000运煤经过顺德容桂水道遭遇河盗抢劫,造成船上两名船员受伤。幸亏及时躲开,要不就砸中头 相似文献
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利用Tribon系统进一步优化船舶涂装生产设计 总被引:2,自引:0,他引:2
通过分析船舶涂装生产设计现状,说明了引进Tribon系统的必要性,介绍了利用Tribon系统、Excel及AutoCAD优化作为船舶生产设计的重点设计内容--<立体分段除锈涂装清册>生产设计的具体方法.通过对实际生产的总结,量化了对船舶涂装生产设计精度与周期的优化效果. 相似文献
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The chain/wire rope/chain combination is a commonchoice for mooring offshore floating platforms. However, data ofthe drag coefficients of chain links are rather limited, resulting inuncertainties with the calculations of the drag force, and hence thedamping of the mooring system. In this paper, the importance of theselection of the drag coefficient is first investigated. Thecomputational fluid dynamics (CFD) method is then used todetermine the drag coefficients of a studless chain under steadyflows. Numerical model validation is first completed by simulatinga smooth circular cylinder under steady flows. In particular, theperformance of different turbulence models is assessed through thecomparisons between the calculations and the experimental results.The large eddy simulation (LES) model is finally selected for thesimulation of steady flows past a chain. The effects of the Reynoldsnumber on the drag coefficient of a stud-less chain is also studied.The results show that the calculated drag coefficients of a stud-lesschain are fairly consistent with the available experimental data. 相似文献
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交通运输部水运科学研究院 《中国远洋航务》2016,(9)
CPSI走势
CPSI指数8月底收于72.8点,与7月收盘相比小幅下跌0.7%,8月CPSI从73点附近震荡,如图l.8月份沪深300指数继续在3300点附近波动,收于3327.8点,CPSI 8月走势逊于沪深300点,如图2.
2016年上半年港口上市公司板块总营收增长停滞,净利润大幅下降10.4%,
其中仅深赤湾、北部湾、南京港和唐山港4家公司净利润保持增长,其余10家港口上市公司净利润均出现不同程度的下降,连云港、锦州港分别下降81.1%和77.3%,显示中型港口受到较大冲击,上港集团、天津港净利润下降幅度较小.港口行业长期以来营收、利润双增长局面即将终结. 相似文献
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在低迷中呈现新的复苏趋势
全球杂货运输需求依然疲弱,Clarkson下调2016年世界杂货海运贸易量增速至1%,其中糖、水泥、铜精矿有望保持5%以上的增幅,钢材和木材预计分别增长2%和1%.中国钢材出口延续增长,全年有望突破1亿吨;铁道机动车辆及风机出口下滑明显;但对外承包工程尤其“一带一路”沿线国家项目维持增势.目前全球共有多用途船3228艘、2962万载重吨.上半年已交付33.8万载重吨,全年预计交付1 20万载重吨,运力存量依然较大.2016上半年,Clarkson 2.1万和1.7万吨多用途船租金均值分别为9258美元/天、8217美元/天,同比下降8.3%和6%. 相似文献