Diffractive interaction for short pulses in 2 × 2 system

This paper studies the asymptotic behavior of the diffractive interaction of pulses with two linear phases of length ε << 1 in 2 × 2 semilinear strictly hyperbolic system with constant coefficients. By a formal analysis, it derives problems of profiles in the expansion of the pulse like solution with respect to the length ε, and obtains that the leading profile satisfies a nonlinear Schrodinger type system. The problems of profiles are solved, and the formal expansion is justified. It is observed that there is interaction between two phases starting at the third order profiles.     

Dynamic response of a surface ship structure subjected to an underwater explosion bubble

Bubble load in a noncontact underwater explosion can cause the ship hull global response and local response. In current literature, the ship hull is usually simplified as a hull girder to analyze its global response. However, literature dealt with the local response of a 3-D surface ship hull subjected to an underwater bubble were limited. This investigation develops a procedure which couples the finite element method with doubly asymptotic approximation (DAA) method to study the problem of transient responses of a ship hull structure subjected to an underwater explosion bubble. Using a 3-D ship model as examples, the global and local responses of the ship model in vertical, transverse and longitudinal directions are performed in detail. The acceleration, velocity and displacement time histories are presented. The characteristics of both the global and local responses of the ship model are discussed. The numerical results show that besides global whipping response, the ship hull also sustains severe local responses in different directions subjected to underwater explosion bubble jetting, which should be taken into consideration.     

网络互动在《船舶高级消防》实操教学中的探索

从《船舶高级消防》实操教学中＂呼吸器＂单项实训入手,总结了网络互动教学在《船舶高级消防》实操教学中的实施过程,并对实施后的教学效果进行了评述。     

摊铺机工作装置与碾压砼相互作用动态特性研究

研制了大型室内碾压砼路面摊铺成型试验设备 ,采用正交试验法 ,在室内进行大量的碾压砼路面实际摊铺试验 ,研究了工作装置的机械参数和碾压砼配合比参数对碾压砼路面的初压实度和可碾性 (综合指标 )的影响规律 ,得出了工作装置与碾压砼相互作用效果最好、路面摊铺成型质量 (指初压实度、提浆性和可碾性 )最佳时的机械参数及碾压砼配合比参数 .     

论哈贝马斯关于劳动与相互作用理论及其现实意义

哈贝马斯在关于劳动与相互作用的理论中,着重探讨了以抽象性的劳动概念为代表的有关人类及其社会的经济活动方式和以相互作用为代表的人类理性实践性之间的关系,并由此表现出：经济社会的发展既是一个体制化,规范化的技术活动,同时也是一个应依据具体的国家、民族 、社会以及化的社会实践。这种观念对一个国家如何在当今经济全球化,一体化中找到最为现实,最为合理的发展形式,具有相当重大的理论指导意义。     

区间测试评估平台的三维交互虚拟场景子系统软件设计

区间信号系统测试评估平台是对铁路区间自动闭塞信号系统进行可靠性、安全性测试及评估的平台。三维交互的虚拟场景子系统是铁路区间信号系统测试平台的一个子系统 ,它为该平台提供了一个虚拟的现场环境。场景子系统划分为 3个子模块 :底层部分、三维模型库、铁路区间仿真部分。底层部分的设计应用了一种支持三维图形重用的动态链接库 (DLL)层次设计方法 ,从而使系统的结构更为合理。基于OpenGL的DLL能提供显示三维图形所必需的各种必要条件 ;能对三维模型库中的基本三维模型进行读取 ,并在OpenGL中重现等。场景子系统的设计中 ,描述了实体的运动层次链接关系和数据结构 ,并实现了三维虚拟场景的建模和铁路区间自动闭塞的仿真。     

不同地质条件下河流对临近建筑物的地震反应影响分析

为了研究不同地质条件下临近河流建筑物的抗震能力及河流存在对建筑物地震反应的影响，分别采用三种适合于软弱场地、中软场地、中硬场地的地震波，对三种场地土、河流与建筑物构成的相互作用体系进行时域内数值分析。计算结果表明，建筑物靠近河流时，体系顶层总位移明显增大，且软弱场地时基础平动与摆动引起的水平位移成分的幅度明显大于中软、中硬场地;场地土越软，基础转动引起的摆动分量和平动分量在体系顶层总加速度中所占比重越大，而结构顶层弹性变形加速度分量则不断减小。     

Dynamic response analysis of a small-scale model tension leg platform

Experimental tests performed on a hydroelastic small-scale model of a tension leg platform for deep water are reported. Comparison between the processed experimental dynamic signals and theoretical responses obtained with a simplified six degrees of freedom model are made. Moreover, some effects of fluid-structure interaction are briefly discussed in the light of results from both impact and wave loading tests.     

An idealized model of interaction between fronds of the large seaweed Durvillaea antarctica

The effect of interactions between individual fronds in a bed of the large intertidal seaweed Durvillaea antarctica, when forced by breaking waves, is studied using a computational model. The model simulates the response of a seaweed bed using a sequence of connected oscillators which are excited by a propagating forcing function representing a breaking ocean wave. Two new facets of the interplay between seaweeds and hydrodynamics are considered: (i) wave forcing due to breaking waves is often not sinusoidal in the rocky intertidal zone and (ii) a frond interaction term is included. The addition of frond interaction reduces the maximum loading on individuals within the bed by around 30% using estimated biomechanical parameters. The rate of change of the loading on the holdfast (equivalent to the “jerk”) is affected in a similar or greater fashion.