Seismic Response Control of Offshore Platform Structures with Shape Memory Alloy Dampers

In this study, the seismic response control of offshore platform structures with Shape Memory Alloy (SMA) dampers is investigated. A new SMA damper and its restoring force medel are introduced for the calculation of seismic response reduction. Based on an actual platform structure and its mechanical medel, the parameters which may affect the rate of shock absorption are analyzed, such as the number, position and characteristics of the SMA dampers and the condition of the site where the platform is located. The results show that the SMA damper is an effective control device for offshore platforms and satisfactory control can be achieved by proper selection of the parameters.     

全数字十二相稳压稳流微机控制系统

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。     

养殖对虾病毒性疾病的细菌并发症防治研究

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。     

海洋沉积物中石英单矿物的化学分离

海洋沉积物中的石英作为陆源物质的标志性矿物,是古环境和古气候演化的信息载体,已成为古环境和古气候演化研究的重要替代指标.提供了改进了的化学分离海洋沉积物中石英单矿物的方法流程.在流程中的不同阶段可有效去掉全样中的生物组分、粘土矿物和长石等,取得海洋沉积物全样的总陆源矿物、石英+长石、石英的相对和绝对含量,通过计算可获得各种组分的通量,通过粒度分析可获得粒度数据.同一样品的17次重复实验表明,含量结果的平均相对误差仅为2.36%;显微镜和X射线衍射分析检查所分离出的石英纯度可达98%以上;激光粒度分析表明,化学试剂对石英的溶蚀作用不明显,不影响粒度分析结果.     

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

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.     

藻体海水培养液中铜的化学存在形式

采用金属络合物通式模型,在IBM-PC计算机上计算了不同pH(7.5～9.5)、碱度(2.3～2.5mmol dm~(-3))和加入不同浓度的铜离子(1.0×10~(-4)～1.0mg dm~(-3))条件下,海水培养液中铜的主要化学存在形式分配的百分数。还给出了计算机程序框图和主要化学存在形式含量的百分数随pH、碱度和铜浓度变化图。     

A Preliminary Study of Oceanic Bomb Radiocarbon Inventory in the North Pacific during the Last Two Decades

Radiocarbon and total carbonate data were obtained near the 1973 GEOSECS stations in the North Pacific along 30°N and along 175°E between 1993 and 1994. In these stations, we estimated radiocarbon originating from atomic bomb tests using tritium, trichlorofluoromethane and silicate contents. The average penetration depth of bomb radiocarbon during the two decades has deepened from 900 m to 1300 m. Bomb radiocarbon inventories above the average value for the whole North Pacific were found widely in the western subtropical region around 30°N both in the 1970s and 1990s, and its area in the 1990s was broader than that in the 1970s. In most of the North Pacific, while the bomb radiocarbon has decreased above 25.4, the bomb radiocarbon flux below 25.4 was over 1 × 10¹² atom m^-2yr^-1 in the subtropical region around 30°N. In the tropical area south of 20°N, the bomb radiocarbon inventory below 25.4 increased from zero to over 10 × 10¹² atom m^-2 during the last three decades. These distributions suggest that the bomb radiocarbon removed from the surface is currently accumulated with bomb ¹⁴C flux of over 1 × 10¹² atom m^-2yr^-1 below 25.4 in the subtropical region, mainly by advection from the higher latitude, and that part of the accumulated bomb ¹⁴C gradually spread southward with about 30 years.     

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

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.     

扇贝肝胰腺化学成分的初步研究

通过多种化学分析方法 ,初步探讨了扇贝肝胰腺组织的化学成分。结果表明 :该组织中含有较丰富的营养物质 ,并含有重要生理活性的 EPA和 DHA,微量元素含量也很丰富。这些结果为扇贝加工后下脚料的利用 ,提供了基础资料     

水下智能潜器的神经网络运动控制

本文介绍一种基于神经网络的水下智能潜器的运动控制方法，该方法通过在线学习，融控制与滤波为一体。计算机仿真与水池实验验证表明，该方法的控制与滤波性能良好，对环境的学习与适应能力强。该方法事实上可用于一般动力系统的控制。