无线Ad Hoc网络中一种基于簇结构的多播路由算法

在无线Ad Hoc网络中，采用分簇的方法将移动自组网进行簇划分，形成由簇头、簇间节点和簇内节点构成的分簇网络结构，从而提供对无线Ad Hoc网络资源进行管理的一种简便构架，文中基于无线AdH oc网络簇结构的特点，提出了一种在无线AdHoc网络中实现的多播路由算法，该算法通过对无线AdHoc网络分簇，形成由簇头和簇间节点构成的虚拟骨干网，再对其进行回路检测和冗余剪枝算法处理，最终得到一个能满足多播要求的多播树．通过对仿真实验结果的分析，该算法具有稳定的数据包发送率，较低的路由建立时间。     

葎草花粉cDNA表达文库的构建和初步鉴定

目的构建葎草花粉cDNA表达文库,为进一步筛选葎草花粉的主要致敏蛋白组分、制备重组变应原奠定基础。方法采集新鲜葎草花粉,过筛后液氮保存,利用Trizol法抽提葎草花粉总RNA,纯化后PCR法反转录合成cDNA。经SfiⅠ酶切,过凝胶柱层析,去除小于400 bp的片断,收集大于400 bp的cDNA片段,加工后与λTripIEx2连接,文库体外包装,取出一小部分感染宿主菌XL1-Blue MRF,检测文库容量;PCR分析插入的cDNA片段的大小及多样性。结果成功构建一个含有5×105重组子的葎草花粉表达文库,重组率为90%,平均插入片段长度约为1.02 kb。结论所建文库容量及插入片段大小合适,适用于筛选克隆的目的cDNA。     

光网络业务恢复算法研究

光网络拓扑结构的变化破坏网络中端到端的连接业务和业务环．根据原有业务路由和结构改变后的网络结构，从原有业务的正向和反向搜索，找出原有业务路由的正向和反向断点；通过回溯法和路由算法搜索出断点之间的路由，连接正向断点之前的路由、断点之间的路由和反向断点之后的路由实现业务恢复。     

一种平面二次包络环面蜗轮副的特征建模方法

平面二次包络环面蜗轮副三维实体属复杂曲面造型，文章在坐标变换公式的基础上，讨论了环面蜗杆螺旋齿面方程，建立了环面蜗杆螺旋线参数方程，并用VBA编程建模．按此建模，用平面包络环面蜗杆产型齿的特征模型，在MDT6．0三维绘图软件环境中实现平面包络环面蜗杆和二次包络蜗轮副的三维建模，并以断面图检验了其良好的接触啮合状态．所生成的实体模型具有给定参数的数字信息，可用于此类环面蜗杆的齿廓形状分析和进一步应用研究．     

电力系统选择性保护仿真研究

针对船舶电力系统的特性,建立了电力系统选择性保护的断路器和熔断器数学模型,利用电磁暂态仿真软件搭建了全系统仿真模型。仿真分析了典型故障下各种瞬动保护设置方案的保护结果,得出了最优的瞬动保护设置方案。     

One-dimensional model on fuel penetration in diesel sprays with gas flow

In diesel engine, spray penetration is usually changed by in-cylinder gas flow. Accurate prediction on diesel spray with gas flow is important to the optimal design of diesel fuel injection system. This paper presents a theory investigation focusing on the penetration of diesel spray with gas flow. In order to understand the effect of gas flow on the penetration of diesel spray, a one-dimensional spray model is developed from an idealized diesel spray, which is able to predict the spray behavior under different gas flow conditions. The ambient gas flow is simplified as ideal flow that has only constant flow velocity along x-axial and y-axial directions of spray. The x-axial and y-axial directions are respectively defined as along and vertical spray directions. The main assumption is that the y-axial direction gas flow has no effect on the penetration of spray along x-axial direction. The principles of conservation of mass and momentum are used in the derivation. Momentum of in-cylinder air flow is also taken into consideration. Validation of the model at stable condition is achieved by comparing model predictions with experimental measurements of diesel spray without gas flow from Naber's experiments. Furthermore, CFD simulations on penetration of diesel spray with gas flow were performed with the commercial code AVL-fire. The onedimensional model is validated by the penetration results with gas flow from CFD calculation. Results show that a reasonable estimation of the spray evolution can be obtained for both with and without ambient gas flow conditions.     

Estimation of maximum road friction coefficient based on Lyapunov method

With the real time and accurate information of motor torque and rotation speed of the four-in-wheel-motordrive electric vehicles, a slip based algorithm for estimating maximum road friction coefficient is designed using Lyapunov stability theory. Modified Burckhardt tire model is used to describe longitudinal slip property of the tire. By introducing a new state variable, a nonlinear estimator is proposed to estimate the longitudinal tire force and the maximum road friction coefficient simultaneously. With the appropriate selection of estimation gain, the convergence of the estimation error of the tire longitudinal force and maximum road friction coefficient is proved through Lyapunov stability analysis. In addition, the error is exponentially stable near the origin. Finally the method is validated with Carsim-Simulink co-simulation and real vehicle tests under multi working conditions in acceleration situation which demonstrate high computational efficiency and accuracy of this method.     

客滚船EEDI研究

能效设计指数(EEDI)对客滚船的要求于2014年4月的第66次环保会上给出。与常规船不同,客滚船属于定制型船舶,影响EEDI结果的参数众多,而且参数之间相互影响、制约。文章首先对计算公式做了详细分析,之后针对几型具有代表性的客滚船的载重量、航速、吃水、主机功率,分析其变化对EEDI的影响敏感度,得出国内航行及中韩航线客滚船当前的EEDI水平,并对如何有效地提高EEDI给出了合理的建议。此外,还对EEDI于客滚船的意义及当前规范存在的某些不合理之处给予了适当评价。     

地下水水力特征对土自重应力计算的影响分析

利用太沙基的有效应力原理,根据地层中地下水的不同水力特征,论述了地下水位以下土自重应力的计算方法.分析认为:常规方法仅适用于潜水含水层和不透水层.实际工程中应根据地下水的埋藏条件等采取合理的计算方法.     

CFD在船舶两种不同推进器中的应用研究

根据船舶螺旋桨和喷水推进器工作的特点,界定了两者数值计算流场控制体的范围.运用结构化与非结构化网格相结合的方法对流场计算区域进行网格划分.通过求解雷诺时均的控制方程,预报了2种推进器的外特性,分析了2种推进器流场的特点,比对了预报结果和试验数据间的吻合程度.比较了CFD在2种推进器上应用的不同点,说明了CFD在螺旋桨和喷水推进上应用的可行性与优缺点.