全数字十二相稳压稳流微机控制系统     

史重光 《中国海洋大学学报(自然科学版)》1994,(Z2)

提出用于十二相可控整流器的８０９８单片机控制系统的电路原理和软件策略。包括自适应控制算法和触发相序计算在内的多种操作全部用软件实现．与通常的方法相比，此系统的成本更低，动态性能和静态性能更好。  相似文献   

养殖对虾病毒性疾病的细菌并发症防治研究   总被引：1，自引：0，他引：1  

苏国成  陈金翠 《台湾海峡》1996,15(2):200-204

本文研究报道了发病对虾肝胰腺分离菌物敏感性，采用防台细菌人工感染方法进行药物饲料的筛选，在实验室及养殖池中进行药物饲料的防治效果试验。结果表明，在对虾病毒流行期间，采用药物饲料可有效防止对虾爆发性大量死亡，提高对虾存活率。  相似文献   

Fuzzy Fatigue Reliability Analysis of Offshore Platforms in Ice-Infested Waters   总被引：3，自引：3，他引：3  

方华灿  段梦兰  贾星兰  谢彬 《中国海洋工程》2003,17(3)

1 .IntroductionTheBohaiGulfisinfestedbyiceinthewholewinter,andoffshorestructuresthereexperiencenotonlywind ,waves ,currentsandearthquake ,butalsoiceloadswhicharecomplicatedbecauseofthedynamicinteractionbetweenicesheetsandstructures.Duanetal.( 2 0 0 0 )hadacomprehensivere viewofthelatestadvancesonice inducedvibration ,fatigueandfractureofoffshorestructures ,payingmuchattentiontothedifferencesinicebreakingmodeanddynamicsofstructuresindifferentice in festedwaters .Theypresentedcriticallythelates…  相似文献   

Robust adaptive control of underactuated ships on a linear course with comfort     

K. D. Do  J. Pan  Z. P. Jiang   《Ocean Engineering》2003,30(17):2201-2225

This paper addresses an important problem in ship control application—the robust stabilization of underactuated ships on a linear course with comfort. Specifically, we develop a multivariable controller to stabilize ocean surface ships without a sway actuator on a linear course and to reduce roll and pitch simultaneously. The controller adapts to unknown parameters of the ship and constant environmental disturbances induced by wave, ocean current and wind. It is also robust to time-varying environmental disturbances, time-varying change in ship parameters and other motions of the ship such as surge and heave. The roll and pitch can be made arbitrarily small while the heading angle and sway are kept to be in reasonably small bounds. The controller development is based on Lyapunov’s direct method and backstepping technique. A Lipschitz continuous projection algorithm is used to update the estimate of the unknown parameters to avoid the parameters’ drift due to time-varying environmental disturbances. Simulations on a full-scale catamaran illustrate the effectiveness of our proposed controller.  相似文献   

浅海桶形基础平台抗拔力与抗倾稳定分析     

薛万东 《海洋科学进展》2001,19(3):87-92

平台在海上受风、浪、流、冰等水平载荷作用产生倾斜 ,而土壤粘接力、摩擦力和土抗力是平台的抗拔和抗倾力 ,桶基平台应满足抗拔、抗倾稳定的要求 ,以保证平台的整体稳定性。讨论了桶基平台受水平力作用时 ,桶形基础的破坏模式及其计算方法 ,阐述了抗倾稳定计算方法  相似文献   

Shear Failure of a Clamped Dented Tubular Beam Under Lateral Impact   总被引：1，自引：0，他引：1  

Wang Deyu  Zhang Shanyuan Associate Prof.  Depart  of Naval Archi.  Ocean Engineering  Shanghai Jiaotong University  Shanghai Prof.  Research Institute of Applied Mechanics  Taiyuan University of Technology  Taiyuan 《中国海洋工程》1996,(2)

- The shear failure of a rigid-plastic dented clamped tubular beam under the lateral impact of a mass is investigated. Both the denting and the impact point are in the middle span of the beam. It is assumed that denting does not spread during the shear sliding. Numerical results show that the axial force and lateral deflection of the beam are very small at the moment of the occurence of shear failure, which means that the finite deformation effect can be neglected in the shear failure analysis. Also, some aspects of the initial impact energy are investigated.  相似文献   

一种产生Fuzzy拓扑和Smooth拓扑的方法及其应用     

岳跃利  方进明 《中国海洋大学学报(自然科学版)》2004,34(2):337-340

利用邻域度给出了1种由fuzzy拓扑产生smooth拓扑的方法;利用smooth拓扑的自身结构给出了smooth拓扑产生fuzzy拓扑的方法,讨论了它们在映射间的联系并引入了强smooth拓扑并获得了一些重要结果.  相似文献   

Effects of chemical ecological adjustment and control experiment on phytoplankton community in the Aoshan Bay     

Chen Bijuan  Zhao Jun  Xin Fuyan  Cui Yi  Guo Feng 《海洋学报(英文版)》2002,21(1):115-123

There is a low nutrient level in the Aoshan Bay. In June 1999, the chemical adjustmentand control experiment was made in the Aoshan Bay. Following tracts investigation was carried out before the experiment and on the 1st, 2nd, 4th, 5th, 6th and 45th day/after the experiment. While the variance of amount of phytoplankton, the replacement of superior species and the species composition of phytoplankton were researched. The results show that the amount of phytoplankton in the Aoshan Bay rises gradually after the experiment. Ceratium macroceros Cleve of pyrophyta was the dominant species before the experiment, its dominant index was 37.7％. Six days after the experiment, its dominant index dropped to 17.6％ . Meanwhile the dominant index of Asterionella japanics Cleve rose from 7.1％ to 39.2％ , it became the first dominant species. Forty-five days after the experiment, the amount of phytoplankton in the Aoshan Bay was 5.15 to 137.32 times more than that in 1997.  相似文献   

Fuzzy Optimum Model of Semi-Structural Decision for Lectotype Optimization of Offshore Platforms   总被引：8，自引：0，他引：8  

CHEN  Shouyu 《中国海洋工程》2001,(4):453-466

In the process of concept design of offshore platforms, it is necessary to select the best from feasible alternatives through comparison and filter. The criterion set, used to evaluate and select the satisfying alternative, consists of many qualitative and quantitative factors. Therefore, the selection is a problem of multicriteria and semi- structural decision- making. Different from traditional methods in semi- structural decision- making, a new framework and methodology is presented in this paper for evaluation of offshore platform alternatives. First, the criterion set is established for the evaluation of alternatives. Next, the approach is studied to construct the relative membership degree matrix, in which both qualitative and quantitative factors are consistent with the uniform calculating standard. And then a new weight-assessing method is developed for calculation of the weights based on the relative membership degree matrix. Finally, a multi-hierarchy fuzzy optimum model is adopted to select t  相似文献   

A dipole mode at thermocline layer in the tropical Indian Ocean     

Tian Jiwei  Liu Huiqing  Qian Weihong 《海洋学报(英文版)》2003,22(1):15-24

Temperature data at different layers of the past 45 years were studied and we found adiploe mode in the thermocline layer (DMT): anomalously cold sea temperature off the coast of Sumatra and warm sea temperature in the western Indian Ocean. First, we analyzed the temperature and the temperature anomaly (TA) along the equatorial Indian Ocean in different layers. This shows that stronger cold and warm TA signals appeared at subsurface than at the surface in the tropical Indian O-cean. This result shows that there may be a strong dipole mode pattern in the subsurface tropical Indian Ocean. Secondly we used Empirical Orthogonal Functions (EOF) to analyze the TA at thermocline layer. The first EOF pattern was a dipole mode pattern. Finally we analyzed the correlations between DMT and surface tropical dipole mode (SDM), DMT and Nino 3 SSTA, etc. and these correlations are strong.  相似文献