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1 .IntroductionOpen oceanaquacultureis becominga newfisheriesindustryasthe human demandfor seafoodin-creases .Consideringthe requirement of environmental protection,thelackof suitable shelteredsitesisforcingfishfarmers to move to more exposed offshore loc… 相似文献
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用流函数理论计算缓坡上波浪的破碎位置 总被引：1，自引：0，他引：1
本文通过理论计算及实验验证发现,在计算缓坡上波浪的变形、特别是确定波浪破碎点时,流函数波浪理论明显优越于线性波液理论。 相似文献
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A three-dimensional non-hydrostatic model based on volumed-averaged, Reynolds-averaged Navier-Stokes (VARANS) equations in sigma coordinate, is applied to simulate the propagation process of irregular wave over a typical fringing coral reef profile, with emphasis on the changes of wave height and wave setup on the reef flat. Compared with the laboratory measured data of several groups of wave and water level parameters, the model is shown to be capable of simulating well the wave transformation over the reef profile with and without porous media. Across all cases, the porous cases decrease the wave height by 12% around the breaking point, and by 28% on the reef flat than the smooth cases. As for the mean water level, the results show that the maximum setdown decreases by 43% on average for the porous cases than the smooth cases, while the wave setup on the reef flat for corresponding porous and smooth simulations is found to agree with an average difference of only 6%. In addition, the variation of porosity in the range 0.47?0.87 auses little effect on the wave setup. 相似文献
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一、Solo分类评价法为地理高考自选模块命题献谋献策
1．Solo分类评价理论概述Solo分类评价法是由比格斯（Biggs）首先提出的,是一种以等级描述为基本特征的质性评价法,在海外有广泛的应用。Solo即可观察的学习成果结构。学生在具体知识的学习过程中,都要经历一个从量变到质变的过程,每发生一次跳跃,学生对于知识的认知就进入更高一级的阶段,可以根据学生回答问题的表现来判断他们所处的思维发展阶段,进而给予合理的评分。基于结构主义学,Solo分类法把学习成果划分为五种结构层次,如表1所示。 相似文献
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3发展土地资源保障与支撑能力分析3.1发展用地预测以2005年为基期,2020年为目标年,分析未来15年内经济圈发展及用地情况。全省人口总量将在2020年左右达到峰值,也将是土地资源承载力的峰值,因此,分析预测2020年左右的用地需求情况对认识经济圈的土地资源保障与支撑能力具有较强的说服力。根据对过去15年经济圈人口与经济增长变化的趋势分析,参考各市“十一五”计划、城市规划及其他相关研究成果,预测到2010年,经济圈内总人口3309万人,其中城镇人口1 661万人,城市化水平50.2%;到2020年,经济圈内总人口达到3 522万人,其中城镇人口2 194万人,城镇化水平62.3%。3.1.1农用地需求预测农用地需求预测的原则是首先确保粮食生产和粮食安全,在此前提下以市场和生态为导向鼓励土地资源的多元化利用。(1)耕地需求量预测。普遍认为小康水平的人均粮食占有量为420 kg/a左右,省会城市经济圈内的德州、聊城两市是全省乃至全国的商品粮基地,因此经济圈在满足区域粮食自给的前提下,还应略有节余,供应区外。由此将人均粮食占有量420 kg/a外推10%,即人均粮食占有量460 kg/a作为2020年目标值。以2... 相似文献
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Numerical Analysis on the Effects of Submerged Depth of the Grid and Direction of Incident Wave on Gravity Cage 总被引：1，自引：0，他引：1
In this paper,the numerical model of the net cage with the grid mooring system in waves is set up by the lumped mass method and rigid kinematics theory,and then the motion equations of floating system,net system,mooring system,and floaters are solved by the Runge-Kutta fifth-order method.For the verification of the numerical model,a series of physical model tests have been carried out.According to the comparisons between the simulated and experimental results,it can be found that the simulated and experimental results agree well in each condition.Then,the effects of submerged depth of grid and direction of incident wave propagation on hydrodynamic behaviors of the net cage are analyzed.According to the simulated results,it can be found that with the increase of submerged depth of grid,the forces acting on mooring lines and bridle lines increase,while the forces on grid lines decrease;the horizontal motion amplitudes of floating collar decrease obviously,while the vertical motion amplitudes of floating collar change little.When the direction of incident wave propagation changes,forces on mooting lines and motion of net cage also change accordingly.When the propagation direction of incident wave changes from 0° to 45°,forces on the main ropes and bridle ropes increase,while the forces on the grid ropes decrease.With the increasing propagation direction of incident wave,the horizontal amplitude of the forces collar decreases,while the vertical amplitude of the floating collar has little variation. 相似文献
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