可用性测试方法在IA研究中的应用

企业进行信息构建时必须研究用户，而可用性测试作为信息构建的重要组成部分，是一种研究用户的有效手段，通过规范的可用性测试过程，可了解用户行为并指导网站设计。作为可用性测试方法的一种，卡片分拣法可以探索用户对于网站信息如何分类，以此提高用户搜索成功率。     

从教学大纲到课程标准看课程功能的转变

一、问题背景 我们处于一个信息化时代、一个需要终身学习的时代、一个需要每一个人都具有终身学习和能力的时代.作为一个国家成功的基础教育应该是能够激发学生继续学习的愿望,成功的学生应该具有继续学习的愿望和能力.     

一个有关函数单调性的命题

给出一个新近发现的关于函数单调性的判别方法。     

贫困山区小学英语教学现状与思考

本文就贫困山区小学英语师资作了调查，从多个方面分析贫困山区小学英语教学的现状，并提出了相应的对策和建议，以推动贫困山区基础教育课程改革。     

基于Google Earth的车辆防碰撞虚拟仿真系统

车载自组织网络（VANET）是近年来智能交通领域的研究热点之一。在VANET网络中,智能车辆通过交互共享道路环境信息,可提高交通安全水平。在现实环境中进行大规模的车载自组织网络实验,在经济性和可行性上都具有较大困难。在SUMO交通仿真基础上开发出车辆防碰撞虚拟仿真系统,通过Google Street Map获取真实道路环境（如路网、楼宇、植被等）,并结合 GEMV2软件对智能车辆在真实道路环境下的无线通讯链路质量进行评估,实现了虚拟行车交通流与车辆间无线通讯质量评估两位一体的模拟仿真,增强了车辆对周围道路交通环境的综合感知能力。     

校企合作是中等职校自我发展的不竭动力

在党中央、国务院的高度重视下，我国的中等职业教育得到了迅猛的发展。各类中等职业学校（以下简称职校）在2004年招生564万的基础上，2005年又实现了扩招100万的目标。一大批职业技能水平较高的操作型人才走上岗位，加快了我国全面建设小康社会的步伐。但是也应看到，由于历史的原因，政府投入不足、在校生人数迅速增加、部分职校先天不足、教学与生产一线脱节等问题，也给中等职校培养社会经济发展所需的合格人才提出了严峻的挑战。笔认为，目前的条件下，要保证职校快速、健康、持续发展，除各级政府要不断加大投入、职校本身强化管理外。走校企合作之路是解决上述问题和职校发展壮大的一条很好的途径，可以说校企合作是职校发展的不竭动力。     

Basic fibroblast growth factor alleviates brain injury following global ischemia reperfusion in rabbits

The aim of this study was to explore the protective effect of basic fibroblast growth factor (bFGF) on brain injury following global ischemia reperfusion and its mechanisms. Brain injury following global ischemia was induced by four vessels occlusion and systemic hypotension. Twenty-four rabbits were randomized into three groups: group A, only dissection of vessels; group B, intravenous infusion of normal saline after reperfusion for 6 h; group C, 30 μg/kg bFGF injected intravenously at the onset of reperfusion, then infused with 10 μg/(kg·h) for 6 h. Serum neuron specific enolase (NSE), S-100B, tumor necrosis factor-α(TNF-α), interleukin-1 (IL-1), interleukin-8 (IL-8) were measured before ischemia, 30 min after ischemia, 0.5, 1, 3, 6 h after reperfusion. Brain water content was determined and cerebral histopathological damages were compared. NSE and S-100B were increased 1 h after reperfusion and reached their peaks 6 h after reperfusion, but were much higher in group B than those in group C 3, 6 h after reperfusion. In groups B and C, TNF-a was increased after ischemia and IL-1 and IL-8 were increased significantly 0.5 h after reperfusion, then reached their peaks 6 h, 3 h, 6 h after reperfusion respectively. TNF-a and IL-8 at the time points of 1 h and 3 h and IL-1 at 3 h and 6 h in group C were correspondingly lower than those in group B. These indices in group A were nearly unchanged. There were less severe cerebral histopathological damages in group C compared with group B, but no difference in brain water content. It could be concluded that bFGF alleviates brain injury following global ischemia and reperfusion by down-regulating expression of inflammatory factors and inhibiting their activities.     

普通话语音与英语语音的对比分析

本文通过对汉语普通话语音系统和英语语音系统进行对比研究,找出它们之间的不同之处, 分析这些差异对中国大学生英语语音习得的影响,并以此来指导英语语音教学。     

Quasi 1D modeling of two-phase flow and deposit formation for urea-selective catalytic reduction systems

A quasi 1D model of two-phase flow for a urea-selective catalytic reduction (SCR) system is developed which can calculate not only the generation of reducing agent but also the formation of deposits in the exhaust pipe. The gas phase flow is solved through Euler method, variables are stored on staggered grids, and the semi-implicit method for pressure-linked equation (SIMPLE) algorithm is applied to decouple the pressure and velocity. The liquid phase is treated in a Lagrangian way, which solves the equations of droplet motion, evaporation, thermolysis, and spray wall interaction. A combination of a direct decomposition model and a kinetic model is implemented to describe the different decomposition behaviors of urea in the droplet phase and wall film, respectively. A new 1D wall film model is proposed, and the equations of wall film motion, evaporation, thermolysis, and species transport are solved. The position, weight, and components of deposits can be simulated following implementation of the semi-detailed kinetic model. The simulation results show that a decrease in the exhaust temperature will increase the wall film region and the weight of deposits. Deposit components are highly dependent on temperature. The urea-water-solution (UWS) injection rate can affect the total mass of wall film and expand the film region, but it has little influence on deposit components. An increase in exhaust mass flow can decrease the total weight of deposits on the pipe wall because of the promotion of the mass and heat transfer process both in the droplets and wall film.     

Experimental and numerical investigation of flow forces in a seat valve using a damping sleeve with orifices

The power of hydraulic piston engines is much affected by the on-off valves which control the fuel injection of the piston assembly. Therefore, the opening time of the seat valve used as the on-off valve is optimized by minimizing the axial flow forces on the spool. A damping sleeve with orifices is proposed to change the valve internal geometry. Experimental and numerical investigations of the flow forces acting on the spool with and without the proposed damping sleeve are carried out to identify the differences in the flow field and to minimize the forces’ effect. The simulated results fit the experimental results well. Both results show that the proposed damping sleeve affects the pressure distribution along the spool cone surface and the jet stream direction significantly. The effects of the orifice’s width, height, and relative sleeve installation positions on the flow field and cavitation are assessed using simulation methods. As a result of the flow field changing, the damping sleeve can reduce the flow forces significantly and even reverse the forces’ direction at the cost of a little flow loss. The opening time of the seat valve can be reduced by 31% to 0.67 ms by using the proposed damping sleeve.