流形上的空间密度聚类算法研究     

刘峰  刘希玉  刘弘 《中国海洋大学学报(自然科学版)》2007,37(4):681-684,626

研究流形上的聚类分析，针对基于密度的空间聚类引入了流形概念，提出1种基于流形的密度聚类算法，该方法将流形的概念与聚类相结合，可以适用于样本为复杂分布的聚类。文中通过实例证明此算法的有效性。  相似文献   

疏浚物倾倒区海水水质级别的模糊综合评价     

刘现明  徐恒振 《海岸工程》1995,14(2):33-37

应用模糊综合评价方法对大连臭水套海域疏浚物预选倾倒区的水质状况进行了评价，得到了有益的结论。  相似文献   

Ex situ target strength of rockfish (Sebastes schlegeli) and red sea bream (Pagrus major) in the Northwest Pacific   总被引：2，自引：0，他引：2  

Kang  Donhyug; Hwang  Doojin 《ICES Journal of Marine Science》2003,60(3):538-543

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Hammerstein型非线性积分方程解的存在性     

白锦东  刘秀元 《中国海洋大学学报(自然科学版)》2002,32(1):152-158

该文采用化为积分方程组的方法 ,利用锥上不动点指数计算 ,在不要求非线性项 f (x,u)非负的情况下 ,证明 Hammerstein型非线性积分方程 φ(x) =∫Gκ(x,y) f (y,φ(y) ) dy非平凡解和多解存在性的一些新的结果。此结果可用来证明非线性常微分方程两点边值问题解的存在性。  相似文献   

The impact of salt water inflows on the distribution of polycyclic aromatic hydrocarbons in the deep water of the Baltic Sea     

Gesine Witt  Wolfgang Matthus 《Marine Chemistry》2001,74(4):246

Salt-water inflows into the Baltic Sea are important events for renewing the deep and bottom waters of the deep basins of the Baltic Sea. These events occur only at irregular intervals. The last strong event was in January 1993 followed by minor inflows in winter 1993/1994. As a result of these inflows, the deep water of the central Baltic basins was completely renewed.Based on extensive observations of polycyclic aromatic hydrocarbons (PAHs) in water, fluffy layer material and surface sediments between 1992 and 1998, the transformation of PAHs and the modification of their distribution in the Baltic deep water is discussed in connection with the spreading of the inflowing highly saline and oxygen-rich water along its pathway from the sills into the central basins. In the course of the inflows in 1993/1994, the PAH concentration in the deep water of the different basins increased significantly. The concentrations were elevated, at least by a factor of 2 and as much as seven to eight times (for the four-ring PAHs) compared to the previous and the following years. Two hypotheses for the causes were discussed: the inflowing salt water may have entrained more highly polluted surface water in the western Baltic Sea, or it may have entrained contaminated fluffy layer material or sediment particles along the route of transport.  相似文献   

Should total landings be used to correct estimated catch in numbers or mean weight-at-age?     

Lewy  Peter; Lassen  Hans 《ICES Journal of Marine Science》1997,54(3):462-470

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汕尾市100kW波力电站空气透平与气室匹配设计   总被引：3，自引：0，他引：3  

梁贤光 《海洋工程》2005,23(1):53-61

根据用1/15模型,在造波水槽中进行试验获得气室的Δ Pi- Q、ηA- Q、 NA- Q特性,以及用300mm透平模型,在1000mm活塞式往复流透平试验台进行试验获得的对称翼透平、双向固定导叶冲动透平和双向自调节导叶冲动透平的CP-、ηT-特性,进行了气室与三种空气透平的匹配设计。表明在设计波况下,采用1.025m的双向自调节导叶冲动透平时,ηT·ηA达50.43%;采用0.975m的双向自调节导叶冲动透平时,ηT·ηA达46.66%;采用0.975m的双向固定导叶冲动透平时,ηT·ηA达33.66%;采用1.45m对称翼透平时,ηT·ηA仅为29.9%。并对四种不同匹配方案进行了对比分析。  相似文献   

裙带菜配子体基因工程选择标记的研究          下载免费PDF全文

张亦陈  高江涛  张喆  姜鹏  秦松 《海洋科学》2007,31(12):64-68

研究了裙带菜(Undaria pinnatifida)配子体对除草剂草丁膦的敏感性以及温度对草丁膦处理效果的影响。结果表明,裙带菜配子体对草丁膦敏感;统计学分析得出了草丁膦在不同温度条件下处理裙带菜配子体的半致死浓度(LD50)及95%可信限;温差达到10℃时,相同处理时间各组内不同处理温度样品的LD50之间呈现显著差异,第6天的LD50由10℃组的15.78 mg/L降为20℃组的11.56 mg/L和25℃组的10.33 mg/L。研究发现可以尝试采用草丁膦作为裙带菜配子体遗传转化的选择试剂。  相似文献   

Microhabitat preferences and depth distribution of combtooth blennies (Blenniidae) in the Gulf of Trieste (North Adriatic Sea)     

Martina Orlando-Bonaca  & Lovrenc Lipej 《Marine Ecology》2007,28(3):418-428

The microhabitat preferences and depth distribution of blenniid species (Blenniidae) in the Gulf of Trieste (North Adriatic Sea) were surveyed using the all‐occurrence sampling method, a non‐destructive visual census method, aided by SCUBA diving. Fourteen species were identified during the entire survey. Four species showed to be indiscriminate in their microhabitat choice while 10 species were classified as infrequent in the surveyed coastal area. A statistically significant correlation was found between the blenniid assemblage and nine microhabitat variables. The blenniid assemblage was divided in two main groups, by the use of canonical correspondence analysis, electivity index, and the depth distribution analysis. The first group comprises species that dwell in surface waters and show a high positive correlation with boulders, the presence of Mytilus galloprovincialis, cirripeds and empty holes bored by Lithophaga lithophaga. The second group includes species that mostly inhabit deeper waters and show a high positive correlation with rocks covered by precoralligenous bioformations.  相似文献   

欧式鳕鱼排的研制   总被引：2，自引：0，他引：2  

桑卫国  吴汉民  韩素珍 《海洋学研究》2002,20(1):55-59

以鳕鱼为原料 ,经过鱼糜制作、调味、速冻、切片、浸液、沾粉、二次速冻等工艺研制开发了欧式鳕鱼排。探讨了原、辅料和漂洗条件对产品质量的影响 ,测定了评价产品质量的感官、理化和微生物指标。  相似文献