On the Survivability of Self-repairing Control System for a Hybrid Underwater Vehicle

A hybrid remotely operated underwater vehicle （HROV） capable of working to the full ocean depth has been developed. In order for the vehicle to achieve a certain survivability level, a self-repairing control system （SRCS） has been designed. It consists of two basic technologies, fault diagnosis and isolation （FDI） and reconfigurable control. For F＇DI, a model-based hierarchical fault diagnosis system is designed for the HROV. Then, control strategies which reconfigure the control system at intervals according to information from the FDI system are presented. Combining the two technologies, it can obtain the fundamental frame of SRCS for the HROV. Considering the hazardous underwater environment at the limiting depth and the hybrid operating modes, an assessment of the HROV＇ s survivability is vitally needed before it enters operational service. This paper presents a new definition of survivability for underwater vehicles and develops a simple survivability model for the SRCS. As a result of survivability assessment for the SRCS, we are able to figure out the survivability of SRCS and make further optimization about it. The methodology developed herein is also applicable to other types of underwater vehicles.     

一种基于HowNet的词语语义相似度计算方法

目前基于How Net的词语语义相似度计算多是根据上下位关系计算语义距离的方法,其结果与人的主观认识存在差异。提出了一种词语语义相似度计算的改进方法,在原有方法基础上,同时考虑影响词语相似度的多种因素,如How Net中义原的深度和密度等,进而挖掘义原间关系,改进原有计算方法。实验结果表明,利用所提出的改进方法计算的词语语义相似度更加贴合人的主观认识。     

基于无线传感网的水下地形监测系统设计

水库、航道等水域的水下地形测量对安全生产至关重要,针对传统方法采用人工测船周期长、成本高的缺点,设计了基于无线传感器网络的水下地形监测方法.该方法利用自行设计的无线水深测量节点,首先采用二维定位算法计算节点平面坐标,并利用超声波测距传感器获得垂直深度坐标,然后利用所有节点的三维坐标进行曲面拟合,重建水下地形.试验和仿真结果表明：该方法有效可行,具有一定的实用价值.     

基于路面使用性能评价的车辙指标研究

文章基于现有沥青路面使用性能评价规范和标准,运用简化的车辙积水模型,围绕高速公路沥青路面车辙深度主观评价标准,针对现有车辙评价模型的不足,通过采用Sigmoid函数,主要探索了车辙深度指数RDI评价模型。结果表明:结合求解的车辙内不致积水的临界车辙深度,将路面车辙深度等级划分为更精细的"轻、中、重"三个等级更加合理;优化的沥青路面车辙深度指数RDI评价模型弥补了现有车辙评价指标的不合理性;在保留现有车辙深度指数评价模型的同时,通过分析路面车辙槽的几何特征增加了车辙的其他指标,初步构建了车辙综合评价模型,对全面评价车辙的危害性及进行路面车辙的养护管理更具有实际意义。     

开采沉陷中采深偏移系数的性质分析

在处理倾斜煤层的开采沉陷数据时,往往采用平均采深代替走向主断面实际开采深度,此时存在着采深偏移系数的情况,不可避免地造成了开采沉陷预测的不准确性.为了提高开采沉陷预测精度,通过理论推导,给出了采深偏移系数计算公式,分析了上覆岩层岩性、煤层倾角、松散层厚度等地质采矿条件对采深偏移系数的影响.同时,结合11个矿区的开采工作面资料,求取了以平均采深代替走向主断面实际采深时各地表移动变形值的偏差.结果表明,采深偏移系数随着覆岩强度和煤层倾角的增加而增加,随基深比的减小而减小.当煤层倾角达到20°以上时,应该考虑采深偏移系数对各移动变形值造成的影响,为矿山开采沉陷准确预测提供参考.     

微-纳米复合陶瓷超声振动磨削的塑性-脆性 转变特征研究

基于工件超声振动磨削的单磨粒运动模型,建立超声振动磨削单磨粒最大切削厚度agm ax公式;基于压痕断裂力学,给出硬脆材料超声振动磨削塑性-脆性转变临界条件,进行超声振动磨削与普通磨削对比试验,应用SEM和AFM分析陶瓷磨削表面微观形貌特征,重点研究磨削参数对其塑性-脆性转变特征的影响。研究结果表明,砂轮平均磨粒尺寸是影响塑性-脆性转变最为主要的因素,砂轮速度对其影响次之,磨削深度对塑性-脆性转变的影响最小;得出只有当agm ax小于临界切削深度agc时,才能实现硬脆材料塑性域磨削的重要结论。     

聚合物微球在油田深部调驱技术中的研究进展

深部调驱技术作为目前提高低渗非均质油藏采收率的有效办法之一,聚合物微球因具有良好的封堵性能和深入性能得到了广泛研究。本文详细介绍了聚合物微球在地层中的深部调驱机理,介绍了聚合物微球的制备方法,综述了聚合物微球的研究内容和研究现状,并指出引入纳米材料合成功能性聚合物微球能有效解决聚合物微球的稳定性,对低渗油藏后期开发具有重要意义。     

钢件的甲酰胺高温气体碳氮共渗

应用气体渗碳的计算机精确控制技术，对常用低碳钢（AISI8720）进行了高温气体碳氮共渗试验，对不同渗碳条件（在不同时间加入不可比例的甲酰胺）下低碳钢的渗层深度和硬度进行了测定和比较分析，得出渗氮介质比较例、时间等因素对于高温气体碳氮共渗过程的影响规律。     

Investigation of Creep Feed Grinding Parameters and Heat treatment Effects on the Nickel-base Superalloys

The Nickel base Superalloys are the most famous complicated and useable of Superalloys to make hot zone components of the gas turbines. The complicated dimensional tolerances, specially at the root of the blade show importance of grinding processes at the production of blades root. The prediction of the effect of machining parameters on the soundness of component surface strengthening for reaching to a suitable surface finishing and avoiding from crack formation at the work part during machining operation often is not easy and feasible so needs to more industrial investigation.This research is about frame 5 blade designed by GE and made from Superalloy IN738LC has been investigated. The formation of a plastically deformed and heat affected zone during grinding of Superalloy IN738LC with a high depth of cut but slow work speed (creep feed grinding) was investigated. Parameters such as work speed, depth of cut and radial dressing speed have been considered as variables and their effects have been studied. During experimental performed, the voltage and current of motor measured and power and special energy calculated.Some samples heat-treated (of the 1176℃ for 1 hr under neutral argon gas and cooling rate of 15℃/min up to 537℃ and then air cooling) to study grains recrystallization. Other samples have been created from the roots of blades and then coated by Nickel to measure boundary layer micro-hardness. The results show that increasing work speed leads to increasing the use power. Increasing the depth of cut, by increasing material removal rate, and the radial dressing speed, by decreasing power, lead to decreasing special energy. The temperature created by grinding lead to decreasing plastic deformation and boundary layer formation. When the radial dressing speed changes from 1 to 0.6μm/rev and other parameters are kept unchanged the roughness of surface increases and the special energy decreases. Sufficient dressing is very essential in limiting the width of the molten zone to few micrometers. As a result, it was found that local melting at contact spots to be a rather common mechanism during grinding of superalloys, lead to so-called white layers which can easily be observed on metallographic cross sections.     

TIG焊和PAW焊中活性剂对焊缝熔深的影响

针对常规TIG焊生产效率低、熔深小等问题，研究了TIG焊和PAW焊中应用活性剂对焊缝熔深的影响。结果表明，应用活性剂后，在同样的参数下，同传统TIG相比，活性剂能够大幅度提高不锈钢、铝合金和钛合金的焊缝熔深。对于PAW焊，熔深也有增加，但是增加的幅度不如TIG效果明显，但对焊缝成形有很好的改善。同时，活性剂对铝合金焊接背面能够起到保护作用。对于钛合金，活性剂除了增加焊缝的熔深外，还能够大幅度地消减焊缝产生的气孔。