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61.
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Fractal Dimension and Fractals in Ocean Engineering 总被引：4，自引：0，他引：4
Fu Yuhua Senior Engineer China Offshore Oil Engineering Corporation P. O. Box Beijing 《中国海洋工程》1994,(3)
- This paper discusses the application of fractal dimension and fractals in ocean engineering. To handle some ocean environment problems, the existing fractal method, in which the fractal dimension is a constant, can be used. For some complicated problems in ocean engineering, this paper presents the concept of the variable dimension fractals (D = f(r)), i. e., the fractal dimension D is the function of characteristic scale r instead of a constant. By using variable dimension fractals, several deformation and stress states of offshore structures are described. 相似文献
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Edward F. Roseman Christine A. Tomichek Tracy Maynard Jennifer A. Burton 《Journal of Sea Research》2005,53(4):309-318
Grubby (Myoxocephalus aenaeus, Cottidae) is a common benthic fish of inshore waters and estuaries of eastern Long Island Sound; however, little information exists on their life history or population demographics. This study utilised a long-term data series (1976–2002) to assess grubby life history and population demographics and explores trends in the Niantic River and Niantic Bay populations. In addition, we examined the age, size, and fecundity of adult grubby in 2001–02 to determine the population characteristics in the region. Mean grubby catch per unit effort (CPUE) in Niantic Bay ranged from 0.4 per trawl in 1976 to 2.9 per trawl in 1984 while river CPUE ranged from 0.4 per trawl in 1977 to 7.6 per trawl in 1989. Catch of grubby in bottom trawls varied seasonally with highest CPUE occurring in winter. Highest entrainment of grubby larvae occurred in 2001 while the lowest entrainment observed was in 1991. Four age classes, 0+ through III+, were derived from otolith analysis (N = 51) although length frequency analysis suggested the possibility of older fish in the population. The total number of eggs in ovaries ranged from 286 to 16 451 for grubby (N = 64) between 52 mm and 155 mm TL. Results of this study indicated a decline in abundance of adult grubby over the 26-year period, possibly related to concurrent declines in eelgrass (Zostera marina) abundance and/or increased water temperature. 相似文献
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The influences of mesoscale eddies on variations of the Kuroshio path south of Japan have been investigated using time series
of the Kuroshio axis location and altimeter-derived sea surface height maps for a period of seven years from 1993 to 1999,
when the Kuroshio followed its non-large meander path. It was found that both the cyclonic and anticyclonic eddies may interact
with the Kuroshio and trigger short-term meanders of the Kuroshio path, although not all eddies that approached or collided
with the Kuroshio formed meanders. An anticyclonic eddy that revolves clockwise in a region south of Shikoku and Cape Shionomisaki
with a period of about 5–6 months was found to propagate westward along about 30°N and collide with the Kuroshio in the east
of Kyushu or south of Shikoku. This collision sometimes triggers meanders which propagate over the whole region south of Japan.
The eddy was advected downstream, generating a meander on the downstream side to the east of Cape Shionomisaki. After the
eddy passed Cape Shionomisaki, it detached from the Kuroshio and started to move westward again. Sometimes the eddy merges
with other anticyclonic eddies traveling from the east. Coalescence of cyclonic eddies, which are also generated in the Kuroshio
Extension region and propagate westward in the Kuroshio recirculation region south of Japan, into the Kuroshio in the east
of Kyushu, also triggers meanders which mainly propagate only in a region west of Cape Shionomisaki.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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结合近年来参与有关水下工程检测和项目监理的实践体验 ,从总结水下工程项目的基本特征着手 ,分析了水下工程项目监理的主要任务 ,并结合对于实施水下工程项目监理必备装备条件的探讨 ,介绍了国内外现有水下监测技术装备的开发应用状况 相似文献
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给出并讨论了海洋系统中由于热量交换、物质交换以及外力做功引起的熵通量的表达式;同时,根据新近调整的全球海 气界面的气候平均资料,估计了全球海洋与大气界面气候年平均的熵通量(熵流),这一熵通量主要取决于海 气界面的热量和物质交换的空间不均匀性。计算结果显示,由热量交换分量引起的熵通量对海洋系统的总熵通量起到主要的贡献作用,其值约为-555.6mW·(m2·K)-1;由海表风应力做功引起的熵通量相对较小,约为-0.09mW·(m2·K)-1;由物质交换引起的熵通量最小,仅为-0.02mW·(m2·K)-1。总的来说,海洋系统从外界获得的总熵通量为-555.7mW·(m2·K)-1,这也就意味着在气候平均定态下,海洋系统内部的熵产生在量值上等于系统的熵交换,即为555.7mW·(m2·K)-1。海洋系统的负熵流与其内部的各种不可逆过程引起的熵产生取得平衡,确保了全球海洋系统处于非平衡热力学定态,并维持着海洋系统中各种尺度的时 空有序现象的消长过程。 相似文献
70.