深水球形接头密封的结构设计和性能分析（英文）

To overcome the current difficulties of high-precision machining and the high manufacturing and maintenance costs of spherical seals for deep-water drilling ball joints, a new spherical seal technique is proposed in this paper. The spherical seal is mainly composed of silicone rubber and polytetrafluoroethylene(PTFE). Rational structural design makes the seal independent from the ball and other components, making it easy to replace if leakage occurs at its surface. PTFE can elastically deform over a certain deformation range, which guarantees that two sealing surfaces fit tightly together. O-Ring and PTFE elasticity makes up for any lack of accuracy during spherical machining and decreases the machining precision requirements for spherical surfaces. Using a finite element technique and nonlinear theory, the performance of the spherical seal under the influence of various factors is determined. The results show that the spherical seal designed in this paper exhibits excellent sealing performance under lowtemperature and high-pressure conditions. The spherical seal, a combination of an O-ring and PTFE, has the advantages of cheap manufacturing and maintenance costs and excellent sealing performance.     

Structural Design and Performance Analysis of a Deep-Water Ball Joint Seal

To overcome the current difficulties of high-precision machining and the high manufacturing and maintenance costs of spherical seals for deep-water drilling ball joints, a new spherical seal technique is proposed in this paper. The spherical seal is mainly composed of silicone rubber and polytetrafluoroethylene (PTFE). Rational structural design makes the seal independent from the ball and other components, making it easy to replace if leakage occurs at its surface. PTFE can elastically deform over a certain deformation range, which guarantees that two sealing surfaces fit tightly together. O-Ring and PTFE elasticity makes up for any lack of accuracy during spherical machining and decreases the machining precision requirements for spherical surfaces. Using a finite element technique and nonlinear theory, the performance of the spherical seal under the influence of various factors is determined. The results show that the spherical seal designed in this paper exhibits excellent sealing performance under low-temperature and high-pressure conditions. The spherical seal, a combination of an O-ring and PTFE, has the advantages of cheap manufacturing and maintenance costs and excellent sealing performance.     

基于相空间重构的冻土路基变形预测

应用最大Lyapunov指数预测多年冻土路基变形,分析冻土路基变形的相空间重构方法和不同延迟时间及嵌入维数对最大Lyapunov指数的影响。发现当延迟时间为1,嵌入维数为5时,最大Lyapunov指数趋于稳定,其值为0．00528。运用该指数,进行冻土路基变形预测,比较预测变形量和实测变形量,得到最大相对误差为0．749％,最小为0．135％。结果表明最大Lyapunov指数能够较好地反映冻土路基变形的混沌特征,利用其进行冻土路基变形预测是可行的。     

基于实时数据的港口电能分析系统

1秦皇岛港电能计量现状秦皇岛港现用电能计量系统的主要功能是电能计费,电能计量数据来自各单位每月上报的《电能消耗统计表》,它是按照电力公司的收费数据填写的,这个数据包含了损耗数据,不是实际发生的电耗（见图1）。现用电能计量系统存在以下问题：     

粉沙质海岸港口航道骤淤防治标准研究

介绍粉沙质海岸界定标准中的泥沙中值粒径参数值,以及粉沙质海岸不同类型划分。结合港口航道淤积特点,提出粉沙质海岸港口航道泥沙骤淤防治设计标准问题;将重现期概念应用于骤淤统计,以此衡量骤淤的强弱;同时,对骤淤重现期的合理防治标准进行论证,给出建议标准值。     

浅谈天津港的纳泥区与泥土利用问题

天津港作为需要常年进行航道、泊位清淤维护的港口,在新建、改建项目实施的同时,应尽快考虑解决能较长期保证清淤维护需要的纳泥区问题。本研究结合天津港南疆港区和北疆港区泊位的清淤纳泥区现状,探讨解决港口纳泥区的必要性,并提出清淤泥土开发利用的建议。     

基于层次分析法的舰船电力系统设计方案决策

文中介绍了一种利用层次分析法进行舰船电力系统设计方案决策的方法。利用层次分析法建立舰船电力系统设计方案决策模型,综合考虑设计方案的经济性、可行性、可靠性、安全性、可维修性等指标,并对设计方案的各项指标进行量化,寻找最优设计方案,为电力系统设计方案决策提供依据。     

基于改进图分解法的多材料车身结构优化设计方法

针对概念设计阶段的车身结构轻量化设计,提出了一种可实现车身多材料结构设计的分层迭代优化方法。该优化方法的设计变量中,除常见的板厚、材料外,还包括装配设计中的拓扑连接,以实现“将合适的材料用在合适的部位”的要求。分层迭代优化的第1层以拓扑连接为设计变量,采用图分解和NSGA-II对车身装配拓扑结构进行多目标优化,最大化车身弯扭刚度和1阶固有频率;第2层对板厚和材料进行多目标优化,最小化车身质量和材料成本。最终采用基于模糊集合的评分公式选定综合最优解,实现了考虑成本的车身结构轻量化设计。     

基于PLC和工控机的船舶电力系统故障诊断装置设计

为保证船舶的安全航行,故提高船舶电力系统的安全性和可靠性十分重要。文中设计了一套基于施耐德M340 PLC、XBTG7340触摸屏和工控机的电力系统故障诊断装置。该套故障诊断装置主要由施耐德M340 PLC、电力系统参数测量装置、XBTG7340触摸屏、工控机、NI数据采集仪、以太网等器件所组成,本诊断装置通过施耐德M340PLC、电力参数测量仪PM800、7个与互感器相连的模拟仪表和NI数据采集仪对船舶电力系统的参数进行相应的采集,将采集到的数据信息通过Modbus现场总线、工业以太网进行数据共享,实现对船舶电力系统装置的监视与检测,并将实时数据导入工控机matlab中进行故障程度与故障类别的判断。     

价格指数法调整利用外资铁路建设项目土建工程价差的操作方法

根据以往铁路建设项目利用外资土建工程采用价格指数法调整价差的实际情况，通过和铁道部实行的价差系数法进行价差调整进行对比分析。归纳出价格指数法调整价差存在的7个方面的差异和问题。分别为调整范围的差异，非调整因子的差异，调整年度的差异，劳务费调整的差异，钢材、木材、水泥及其他材料权重的差异，机械使用费调整的差异，调差地区划分的差异。并针对上述差异和问题进行分析，找出存在差异的主要影响因素，总结出一套既符合铁路项目投资管理及真实反映工程造价水平，又符合铁路实际情况及与国际惯例接轨的外资土建工程价格调整公式。