海运精矿粉及含水矿产品运输安全的几点建议

从2010年10月下旬到12月上旬,我国从菲律宾、印尼进口红土镍矿的船舶连续在巴士海峡和台湾海域发生了5起船翻人亡的重大事故,这给船公司和进口国港口国监督机构提出了一个不能回避的问题。作为进口红土镍矿粉的港口国,我国颁布的相关规定     

起重船数据库系统的开发研究

针对起重船设计开发中对母船选型及改造技术的需要,提出了采用关系型数据库Access构建起重船数据库系统.用户可通过VBA使用ADO获取数据库中的信息,并利用系统与Excel的无缝连接导出完整数据,达到了船舶型值信息输入输出自动化的目的.该数据库能够方便快速的存储和查询所需要的船型信息,提高船体与起重负荷的相互匹配,缩短母船选型与改造的研制周期.     

挖泥船绞刀二维清水流场数值模拟

基于时均N-S方程对绞刀内部及周边流场进行二维数值模拟分析,采用标准k-ε湍流模型与多参考系模型对绞刀进行动静耦合的定常数值计算,获得不同绞刀转速与泵吸流量组合时的流场状态。以定常湍流计算作为初始条件应用RNG k-ε模型和滑移网格技术进行了绞刀流场的非定常数值计算,得到了流场参数随时间变化及动静区域间的影响与干涉。研究成果有助于初步认识绞刀内部及周边流场,可供绞刀设计及挖泥船施工参考。     

Improving travel efficiency by parking permits distribution and trading

In this paper, we study various parking management schemes in a many-to-one network, where each origin is connected to the destination by a highway with a bottleneck and a parallel transit line. First, we derive a model to compute the morning commuting pattern when the destination has inadequate parking space to accommodate potential private cars. Second, we propose and compare the following three schemes of distributing parking permits to commuters residing in different origins: uniform, Pareto improving, and system optimum distribution of parking permits. Third, free trading of parking permits among commuters in a free market is introduced to better cater for commuters’ parking needs. Numerical examples show that parking permits distribution and trading are very efficient in traffic management.     

Research on the strategy of underwater united detection fusion and communication using multi-sensor

In order to solve the distributed detection fusion problem of underwater target detection, when the signal to noise ratio (SNR) of the acoustic channel is low, a new strategy for united detection fusion and communication using multiple sensors was proposed. The performance of detection fusion was studied and compared based on the Neyman-Pearson principle when the binary phase shift keying (BPSK) and on-off keying (OOK) modes were used by the local sensors. The comparative simulation and analysis between the optimal likelihood ratio test and the proposed strategy was completed, and both the theoretical analysis and simulation indicate that using the proposed new strategy could improve the detection performance effectively. In theory, the proposed strategy of united detection fusion and communication is of great significance to the establishment of an underwater target detection system.     

人工气泡船水动力性能试验研究

文章通过试验途径研究了人工大气泡船的水动力性能,试验包括气泡船流量测试试验、气泡船通气对比试验、气泡船与其原型船静水及波浪中对比试验。结果表明,气泡船充气后阻力能大大下降;对于气泡船有一最经济的充气流量;气泡船在静水及波浪中的综合性能均优于常规船型,特别是阻力下降很多。根据试验结果还分析了气泡降阻的原理:具有一定压力的气泡腔,除了减小船底的摩擦阻力之外,还支撑了艇的一部分重量,减小了艇体的吃水,从而阻力也相应地减少。     

磁阻传感器在载波相位测姿中的应用

GPS载波测姿精度高、启动快,但容易受干扰影响,存在固有的周跳现象.为此提出了一种利用磁阻传感器辅助GPS测姿的新方法,基于载波测量的双差方程,通过基线长度和磁阻航向的双重约束,提高模糊度估计的可靠性和测量的稳定性.实际测试结果表明,该方法有效地剔除了载波姿态测量的异常值,具有应用价值.     

远离大陆辐射沙洲人工岛建设关键技术的探讨

江苏洋口离岸13 km外海辐射沙洲上建设大型人工岛,具有浅海、无遮掩、风浪大、潮差大、工程量大、工期急迫、施工依托条件差等特点。通过对建设过程中采用的主要关键技术实施情况、效果评价以及工程实施过程中遇到的技术问题及分析,探讨和总结外海辐射沙洲上建设人工岛的关键技术,为人工岛后续建设和类似工程提供借鉴。     

高比转速轴流式和斜流式泵喷水推进器推进特性分析

对比比转速同为ns=769的两个轴流式叶轮和斜流式叶轮的水力性能和推进性能,分析其做为泵喷水推进器叶轮的适用性。分析结果表明,就所研究的两个叶轮而言,斜流式叶轮的高效区更宽,当做为泵喷水推进器叶轮使用时,轴流式叶轮的结构更紧凑、最大推力更大、最大推功比也更大。因此轴流式叶轮比斜流式叶轮更适合于用做泵喷水推进器的工作叶轮。