基于多小波基维纳滤波图像去噪

提出一种多小波基维纳图像去噪方法。它把多个小波基用于小波维纳滤波图像去噪，利用多个小波各自独有的特性和维纳滤波估计最小误差估计的优点，达到对图像更有效去噪的目的。实验结果表明，该方法可以有效降低图像噪声，同时，较好地保持图像视觉效果。     

载荷对接触热导的影响的实验研究

接触界面热导是工程热设计中的一个重要参数,目前国内外普遍采用稳态法进行测量。但该法不能测试大塑性变形下的接触热导。在许多工程应用如双辊连续铸轧中,材料发生大应变塑性变形,其变形率达到50％以上,本文利用瞬态法对大变形条件下的接触热导进行了测试,测试结果表明当接触压力远远超过接触试样中硬度较小的试样的屈服极限以后接触热导变化趋于平缓,接触热导值相对于小压力条件有显著提高。     

阳极氧化处理增强Al-Li合金胶接板剪切强度的机理

为揭示磷酸阳极氧化处理后Al-Li合金胶接接头剪切强度大幅度增强的机理,分别对其进行机械打磨和磷酸阳极化表面处理,并选用不同的分析仪器对表面处理后的Al-Li合金表面微观形貌、粗糙度、表面润湿性和表面自由能进行测试计算和分析。结果表明,机械打磨后仅在Al-Li合金表面留下纵横交错的沟槽,而磷酸阳极化处理后使得Al-Li合金表面产生了微观粗糙的多孔膜,增加了胶层与合金表面的接触面积,改善了胶质分布的均匀性;磷酸阳极化处理后Al-Li合金表面自由能明显提高,改善了粘接界面的润湿性能。两方面的共同作用,使得胶接界面的抗剪切能力大幅提高。     

Rheological behavior of continuous roll casting process of aluminum alloy

The rheological behavior of aluminum alloy and its influencing factors in physical simulation of continuous roll casting process were studied by using a Gleeble-1500 thermal-mechanical simulation tester with a set of special clamp system. The relationships between the flow stress and the strain rate in the deformation process of simulating roll casting experiment were obtained. The results show that four different characteristic stages exist in the temperature range of the whole rheological process. The first occurs when the temperature is higher than 600℃, which belongs to the creep deformation stage; the second occurs when the temperature lies in the range of 500 - 600℃, and it can be regarded as the high temperature and low stress level deformation stage; the third occurs when the temperature decreases to the range of 300 - 500℃, it is considered to be the middle stress level deformation stage; the last occurs when the temperature is less than 300℃ and the strain rate is less than 1.00 s^-1 , it belongs to middle stress level deformation stage. But when the strain rate is larger than 1.00 s^-1, it belongs to the high stress level deformation stage. And the relative constitutive models suitable for the four different stages of continuous roll casting process were established through multivariate linear regression analysis of the experimental data.     

浅谈校园网的规划设计与管理

随着网络技术迅速发展,校园网的建设已成为各级各类学校实现教育现代化、管理信息自动化不可缺少的基础设施之一。概述了校园网的规划设计方法,对校园网的硬件和软件的设施提出了需求,最后介绍了校园网的安全、故障维护和流量管理的方法,并对校园网的日常管理维护提出了自己的见解。     

Model-based parameter identification of comprehensive friction behaviors for giant forging press

A new experimental apparatus was set up to investigate the actual fi-iction characteristics on the basis of speed control of the serve system.A modified friction model was proposed due to real time varying deformation resistance.The approach to identify the parameters of comprehensive friction behaviors based on the modified model was proposed and applied to the forging press.The impacts on parameters which the external load had were also investigated.The results show that friction force decreases with velocity in the low velocity regime whereas the friction force increases with the velocity in the high velocity regime under no external load.It is also shown that the Coulomb friction force,the maximum static friction force and the vicious friction coefficient change linearly with the external load taking the velocity at which the magnitude of the steady state friction force becomes minimum as the critical velocity.     

基于SQL Server的SQL注入攻击防范方法

在基于SQL Server服务器的Web应用程序中,确保安全性是一个重要而复杂的问题。该文针对SQL Server数据库的安全性,介绍了SQL注入攻击概念及几种常用的攻击方法,从两个方面提出了一些防范SQL注入攻击方法,最大限度地减少SQL注入攻击的可能性,尽可能保证SQL Server数据库的安全性。     

基于SOL Server的SOL注入攻击防范方法

在基于SQL Sepvep服务器的Web应用程序中,确保安全性是一个重要而复杂的问题。该文针对SQL Sepvep数据库的安全性,介绍了SQL注入攻击概念及几种常用的攻击方法,从两个方面提出了一些防范SQL注入攻击方法,最大限度地减少SQL注入攻击的可能性,尽可能保证SQL Sepvep数据库的安全性。     

模糊PID在液压机位置控制系统中的应用

大型模锻液压机活动横梁的位置控制与运行可靠性对产品精度至关重要,针对活动横梁位置控制高精度、大滞后和大惯性等特点,提出了基于位移反馈的五驱动缸主动平衡系统.结合PID和模糊控制的优点,设计开发了基于S7-300 PLC的模糊PID参数自整定控制算法,利用模糊推理对PID参数K<,P>,T<,I>和T<,D>进行在线自整...     

基于AMESim的模锻液压机驱动系统动态特性分析

模锻液压机系统是一个多重耦合的非线性系统,影响参数众多,很难建立精确的数学模型进行研究.本文基于系统工程高级建模和仿真平台AMESim建立了Y32-315T型四柱液压机驱动系统的仿真模型,通过实验验证了模型的合理性;在此基础上对液压机驱动系统的阶跃响应进行了仿真分析,结果表明系统响应速度较快,具有较好的动态品质.