涵洞基坑降水方案比选与参数分析

结合哈大铁路客运专线DK651+972涵洞施工的实例,论述了根据实际水文地质条件确定降水方案,对以往经验参数进行修改,以达到降水目的及确保工程顺利进行。     

无石棉隔膜在碱性电解水领域的应用

介绍了碱性固体电解质和聚苯硫醚非织布两种无石棉隔膜在碱性电解水领域的应用,它们耐高温、耐腐蚀、隔膜电阻低、测试时间内电性能优良,作为石棉隔膜的替代物具有一定研究价值。     

充分发挥道路客运在综合运输体系中的比较优势

以石太客运专线的开通为例,分析了高速铁路的开通对道路运输业造成的冲击,阐述了道路运输相对于铁路运输的优势,并从充分发挥道路运输业比较优势的角度提出了切实可行的建议。     

Water entry of a bow-flare ship section with roll angle

The two-dimensional water entry of a bow-flare ship section with constant roll angle, or heel angle, was studied by using a boundary element method. The fully nonlinear free surface conditions and exact body boundary conditions were satisfied. Nonviscous flow separation from the knuckles of the section or from the curved bottom could be simulated. The numerical calculations were compared with existing experimental results. First, the effects of roll angle were investigated and then the characteristics associated with large roll angles were examined in particular. The evolution of the free surfaces and the pressure distributions on the section surface are illustrated and the influence of nonviscous flow separation from the leeward section surface is discussed.     

基于LM算法的组合导航系统的故障诊断

LM (Levenberg-Marquardt)算法是梯度下降法与高斯-牛顿法的结合,在训练次数与精度上明显优于标准的BP算法.介绍了BP神经网络,采用LM算法对标准BP算法进行改进,并应用于船舶组合导航系统的故障诊断.仿真结果表明,LM算法可有效地提高学习速度,缩短训练时间,诊断效果好.     

深水试验水池大型升降平台多电机同步控制

深水试验水池是开展深海装备开发必不可少的试验手段,大型升降平台是其中的关键设备.大型高精度、高转速传动系统的多电机同步控制是最为核心的问题之一.同步控制算法的优劣直接影响系统的性能与可靠性.提出深水试验水池大型升降平台多电机同步协调控制系统构成方案,并提出一种新的基于拉力死区误差均衡及中心耦合误差的升降平台多电机同步协调控制策略,实现了拉力控制和位置控制的解耦;同时,提出了多电机控制的升降平台仿真系统,其仿真结果表明:所提出的控制策略同步稳定性能高、收敛速度快,具有很高的应用价值.     

基于博弈论的船舶电力系统脆性负熵流分析

将博弈论引入到船舶电力系统性负熵流研究中,研究表明,船舶电力系统务子系统对负熵的获取是满足极大熵准则下的非合作博弈.通过仿真表明船舶电力系统务子系统对负熵流的合理获取对船舶电力系统的安全稳定性至关重要.     

Unsteady finite-depth effects during resistance tests on a ship model in a towing tank

This paper covers an extension of the study of Doctors et al. (J Ship Res 52(4):263–273, 2008) on oscillations in wave resistance during the constant-velocity phase of a towing-tank resistance test on a ship model to the case of relatively shallow water. We demonstrate here that the unsteady effects are very prominent and that it is essentially impossible to achieve a steady-state resistance curve in a towing tank of typical proportions for a water-depth-to-model-length ratio of 0.25. This statement is particularly true in the speed region near a depth Froude number of unity. However, on the positive side, we show here that an application of unsteady linearized wave-resistance theory provides an excellent prediction of the measured total resistance, when one accounts for the form factor in the usual manner. Finally, a simple application of the results to the planning and analysis of towing-tank tests is presented.     

无人水下航行器实时系统设计

针对集中式体系结构已不能满足无人水下航行器(UUV)越来越复杂的水下任务,设计并实现了UUV实时系统,该实时系统以分布式结构为基础,在硬件上采用CAN总线技术,减少了通信时间,提高了实时性,简化了系统,并提供了良好的扩展性;在软件设计上采用μC/OS实时操作系统,方便地实现了逻辑复杂的程序,并进一步满足了系统的实时性.仿真和实时性测试试验结果表明,该系统软、硬件设计满足程序运算、数据存储和实时性的要求,并具有较高的可靠性.     

一种自带能源的观察型ROV控制体系结构

介绍一种自带能源的观察型微细光缆遥控潜水器控制系统的结构和组成.FROV自身携带锂离子电池用于水下系统的供电,同时采用细光缆进行水下、水面系统的通讯.FROV具有水下机动性较好,活动范围较大等特点.