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91.
The effect of test panel submersion season on the colonization of biofouling communities in a tropical coast revealed that the effects of panel submersion time should be taken into consideration for modelling fouling community recruitment dynamics in coastal systems or during the field trials of antifouling coatings. Wooden test panels fitted onto a raft were submerged during pre-monsoon, monsoon and post-monsoon seasons for the development of the biofouling community. Results showed considerable variation in the colonization of fouling communities on test panels submerged during different seasons. Barnacles, tubeworms, ascidians and seaweeds were the major fouling communities that colonized the test panels. The total biomass of the fouling communities that settled on the post-monsoon season panels varied from the initial value of 2.72 g dm−2 to a maximum of 44.5 g dm−2. On the panels submerged during monsoon season, the total biomass of fouling communities varied between 0.78 g dm−2 and 69.9 g dm−2. The total fouling biomass on the pre-monsoon season panels varied between 2.95 and 33.5 g dm−2. Barnacles were the initial colonizers on the panels submerged during pre-monsoon and post-monsoon seasons. Soft-bodied organisms such as ascidians dominated the monsoon season-initiated panel series during the initial period. 相似文献
92.
Robust control based on feedback linearization for roll stabilizing of autonomous underwater vehicle under wave disturbances 总被引:1,自引:0,他引:1
In the case of Autonomous Underwater Vehicle(AUV) navigating with low speed near water surface,a new method for design of roll motion controller is proposed in order to restrain wave disturbance effectively and improve roll stabilizing performance.Robust control is applied,which is based on uncertain nonlinear horizontal motion model of AUV and the principle of zero speed fin stabilizer.Feedback linearization approach is used to transform the complex nonlinear system into a comparatively simple linear system.For parameter uncertainty of motion model,the controller is designed with mixed-sensitivity method based on H-infinity robust control theory.Simulation results show better robustness improved by this control method for roll stabilizing of AUV navigating near water surface. 相似文献
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Shannon H. Nudds Jennifer A. Shore 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(11):1060-1068
Mesoscale eddies can distribute nutrients, heat and fresh water into the Gulf of Alaska (GOA) from the coastal margins. While many studies have investigated the physical characteristics of GOA eddies, their effects on passive-dispersive particles have not been previously simulated to investigate eddy induced upwelling. A climatologically forced Parallel Ocean Program simulation of the north Pacific Ocean with an online particle tracking scheme was used to simulate passive-dispersive particles in the Gulf of Alaska. In-eddy vertical Lagrangian velocities of the particles were calculated both inside and outside the eddies and showed upwelling rates are generally greater inside the eddies where the vertical velocities of the particles ranged from 0.2 to 0.7 m/day. 相似文献
95.
在对研究区地震资料精细解释的基础上,对原阳江凹陷及其南缘低凸起重新进行了构造单元划分。阳江低凸起北支将原阳江凹陷分隔为阳江东、西两个凹陷,阳江东凹陷可以进一步分为东1洼和东2洼。阳江北断裂是阳江东、西两个凹陷主要的控凹断裂,根据断裂走向拐点和阳江东、西凹陷的分界可以把阳江北断裂划分为3段,分别是西段、中段和东段,西段控制阳江西凹陷,中段控制东1洼,东段控制东2洼。断裂各段活动规律不同,其中断裂中段控制的东1洼的主要活动期在晚始新世和早渐新世,控制文昌组和恩平组的湖相沉积,勘探潜力最好。继承、叠加发育的伸展构造样式是阳江东、西两凹陷的主要构造样式,断层型圈闭和披覆背斜型圈闭是该地区发育的主要圈闭类型。勘探实践表明,垂向运移和近源成藏是阳江东、西两凹陷主要的成藏规律。 相似文献
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97.
研究路面粗糙度扰动作用下的汽车主动悬挂系统的减振控制问题。首先简化单自由度四分之一悬挂系统模型,建立路面粗糙度扰动模型。然后基于内模原理设计汽车主动悬挂系统的减振控制结构,并利用线性系统的极点配置方法设计系统的减振控制律。最后利用数字仿真验证了减振控制律的有效性。 相似文献
98.
99.
目标跟踪中参考模型的初始化大多需要手动完成,现有的自动初始化方法也存在明显缺陷,针对这些问题提出了一种自动、精确初始化参考模型的方法。首先采用连通组分标记算法对目标进行计数,并计算每个目标的位置;然后根据回转半径张量法求出包含目标的最小外接矩形;最后从最小外接矩形的参数出发用蒙特卡洛算法求出参考模型的估计。实验结果表明在不同的场景下算法均能准确完成参考模型的初始化,计算出的模型能够体现目标的视觉特征。 相似文献
100.
WANG Qing LU Zhanguo . Key Laboratory of Geo-detection of Ministry of Education China University of Geosciences Beijing China 《东北亚地学研究》2011,(2)
In the conditions of low Signal-to-Noise Ratio(SNR) of seismic data and a small quality of log information,the consequences of seismic interpretation through the impedance inversion of seismic data could be more precise. Constrained sparse spike inversion(CSSI) has advantage in oil and gas reservoir predication because it does not rely on the original model. By analyzing the specific algorithm of CSSI,the accuracy of inversion is controlled. Oriente Basin in South America has the low amplitude in geological... 相似文献