复合材料箱梁非线性分析的本构方程研究

在考虑几何非线性的前提下,计入各种耦合效应,利用复合材料层合板理论对薄壁层合箱梁的约束扭转进行了分析,给出了杆端内力的计算公式,并指出能量方法在解此类复杂问题时不易解出其精确解.     

射击误差分析及仿真

射击误差仿真,是解决命中问题的关键。文章通过对射击误差源的分析,将误差分为系统误差和随机误差分别进行仿真,针对复杂外形目标介绍了两种处理方法,论述了解析积分法和蒙特卡洛法两种在仿真中的应用。     

CFD理论黏性流场中三维振动水翼的非定常水动力性能(英文)

The motion of the fins and control surfaces of underwater vehicles in a fluid is an interesting and challenging research subject. Typically the effect of fin oscillations on the fluid flow around such a body is highly unsteady, generating vortices and requiring detailed analysis of fluid-structure interactions. An understanding of the complexities of such flows is of interest to engineers developing vehicles capable of high dynamic performance in their propulsion and maneuvering. In the present study, a CFD based RANS simulation of a 3-D fin body moving in a viscous fluid was developed. It investigated hydrodynamic performance by evaluating the hydrodynamic coefficients (lift, drag and moment) at two different oscillating frequencies. A parametric analysis of the factors that affect the hydrodynamic performance of the fin body was done, along with a comparison of results from experiments. The results of the simulation were found in close agreement with experimental results and this validated the simulation as an effective tool for evaluation of the unsteady hydrodynamic coefficients of 3-D fins. This work can be further be used for analysis of the stability and maneuverability of fin actuated underwater vehicles.     

改进的BP神经网络在路基沉降预测中的应用

针对传统BP神经网络存在的缺点,提出基于遗传优化的变梯度反向传播的BP神经网络预测方法,采用遗传算法优化BP神经网络的初始权重,建立路基沉降预测模型。该模型可克服BP神经网络模型存在的收敛速度慢、易陷入局部极小点等缺点。结合现场实测数据,将该优化模型与指数曲线模型、双曲线模型、灰色预测模型和传统BP神经网络预测模型对比,结果表明改进的BP神经网络在路基沉降预测中精度最高,适宜于广泛推广应用。     

船用柴油发电机模拟机的设计

柴油发电机是舰船上重要的电源装置,它的性能直接影响到船上的电力系统性能。本文以某船用12相、8极柴油发电机为原型,详细阐述了其模拟机的设计方法。其模拟机的研制,对船上电力系统动态模拟和研究、船用柴油发电机的设计和研制提供了新的手段。     

黄土地区既有铁路基床病害整治加固技术研究

分析了黄土地区既有铁路基床病害类型及产生原因,提出了基床病害防治及整治基本思路和措施,并在宝中铁路防洪加固中进行了应用,取得了较好的技术、经济效果。     

大烧失量粉煤灰在石安高速公路建设中的应用

通过对大烧失量粉煤灰化学成分及工程性质分析,结合工程实例中粉煤灰填筑路堤及二灰砂底基层施工经验,总结出大烧失量粉煤灰在高速公路建设中的若干经验。     

双灰桩加固黄土路堤边坡稳定性分析及应用

边坡溜坍是土质路基常见的一种病害现象。本文利用双灰桩法加固既有铁路黄土路堤边坡,分析了压实黄土、双灰材料强度特性及变化规律;建立了双灰桩加固路堤边坡浅层溜坍分析计算方法;并结合实际工程应用研究了加固效果。     

Separation and visualization of arteries and heart in 3D computed tomography angiography images

The visualization of arteries and heart usually plays a crucial role in the clinical diagnosis, but researchers face the problems of region selection and mutual occlusion in clinical visualization. Therefore, the arteries and the heart cannot be easily visualized by current visualization methods. To solve the problems, we propose a new framework for arteries and cardiac visualization by combining a priori knowledge and the set operations. Firstly, a suitable region can be easily determined in the transfer function space with a priori knowledge and the visual feedback results. Secondly, the arteries and the heart can be directly extracted by the marked seed point. Finally, the arteries and the heart are separated for solving mutual occlusion through the set operations. This framework can easily solve the mutual occlusion problem in clinical visualization and greatly improve the region selection method in the transfer function space. Its effectiveness has been demonstrated on the basis of many experimental results.     

城市轨道交通应急能力影响因素及评价研究

为分析和评价城市轨道交通应急能力的影响因素,构建了城市轨道交通应急能力影响因素三级指标.提出了一种集成DEMATEL-ISM-TOPSIS(决策试验分析与评价-解释结构模型-优劣解距离)法用于分析与评价,厘清了评价因子的层级关系和主从逻辑关系以探究各指标的属性.通过原因度和中心度得分分析了城市轨道交通应急能力的关键因素和核心影响因素,构建了应急能力因素象限分布图;通过ISM分析了表层和深层次的影响因素,基于各评价因子的逼近理想解对指标客观赋权;最后对3条轨道交通线路打分评价,表明了评价指标的适用性和研究方法的科学性.