不同屈强比的冷轧DP780钢工艺调控技术分析

采用不同的工艺调控技术，实现了一种成分体系可生产具有不同屈强比的经济型冷轧DP780钢，并通过分析力学性能测试结果、TEM和SEM组织形貌特征，得到热轧初始组织、冷轧压下量、连续退火工艺对屈强比的影响。结果表明，当热轧初始组织为F＋P(铁素体＋珠光体)时，随着平均晶粒尺寸细化至约7.5 μm，屈服强度增加了50 MPa，屈强比由0.48增至0.56；当热轧初始组织变为F＋B(铁素体＋贝氏体）、以贝氏体为主时，屈服强度达到532 MPa，屈强比增至0.65，同时有利于保证DP780钢的扩孔性和塑性，扩孔率达到86%，特别适用于有扩孔翻边要求的汽车结构件和加强件。此外，适当增加冷轧压下量和降低退火保温温度，均有利于增强基体的强化效应，从而提高屈强比。     

Influences of copolymers (Copovidone,Eudragit RL PO and Kollicoat MAE 30 DP) on stability and bioactivity of spray-dried and freeze-dried lysozyme

Protein stability is the most crucial factor in protein pharmaceutical preparations. Various techniques were applied for producing stable protein formulations such as spray-drying and freeze-drying. However, heating and freezing stresses are disadvantages for proteins using these methods, respectively. Accordingly, excipients have been used to preserve therapeutic effects of proteins during processing and for long period of time. Therefore, influences of Copovidone, Eudragit^® RL-PO and Kollicoat^® MAE-30 DP (as excipients) on stability and integrity of lysozyme (as a model protein) in spray-dried and freeze-dried forms were investigated. Protein formulations in both dried forms were prepared without and with the addition of mentioned excipients at different concentrations. Protein formulations were characterized for yield determination, morphology using scanning electron microscopic (SEM), thermal analysis by Differential Scanning Calorimetry (DSC), secondary structure stability using Fourier transform infrared (FT-IR) spectroscopy and biological activity. All protein formulations were subjected to a stability study as solid protein formulations for 3 weeks at 24?°C/76% relative humidity and aqueous protein samples were stored at 50?°C for 30?min in a water bath. Results showed that Copovidone successfully preserved integrity and biological activity of lysozyme before and after storage in both spray-dried and freeze-dried forms with more advantage for using higher concentration of the same excipient. Smooth spheres of spray-dried lysozyme formulations with Copovidone were smaller than spray-dried lysozyme without and with Kollicoat^® MAE-30 DP, which affected %yield produced. Copovidone has demonstrated valuable protection ability for lysozyme.     

基于西门子数字驱动伺服611U 的钢轨锯钻床控制系统

近年来,我国铁路客运专线的建设得到高速发展,对钢轨质量提出了更高要求,对钢轨定尺的准确性和钻孔的质量要求也越来越高,通过采用西门子数字驱动伺服611U装置结合上位机PLC系统的步序逻辑控制,能够很好的完成钢轨的定尺和锯钻,大大提高了产品的加工精度.     

组合与概率的连续特征权衡量化方法

连续特征量化方法是数据挖掘方法中必要的预处理过程。呈现一种组合与概率的连续特征权衡量化方法。基于最小描述长度以及组合与概率理论,提出连续特征量化的权衡标准,能够在量化所导致的分类错误与量化区间信息之间得到合理的权衡;基于该权衡标准提出一种有效的动态规划量化算法,以找到最好的量化结果;量化后的数据采用naive贝叶斯分类器进行分类预测,与其他连续特征量化方法的对比实验结果表明,新方法得到了较高的平均学习精度。     

三角域上三次DP曲面的扩展

给出了三角域上带双参数的四次DP混合函数,它是三角域上三次DP基函数的扩展。分析了该组混合函数的性质并定义了三角域上带双形状参数的四次DP参数曲面。该组混合函数及其参数曲面分别具有与三次DP基函数及三次DP参数曲面类似的性质。当两参数为0时,可分别退化到三次DP基函数及三次DP参数曲面。研究表明,通过改变两个形状参数的取值,既可整体又可局部调整曲面的形状。     

工业设计在三维打印时代面临的发展变化

以三维打印技术在材料、工艺、成型方式等方面的发展变化与应用前景为启示,分析三维打印技术的发展趋势对未来制造业格局、生产方式、商业模式及人们生活方式带来的改变和影响。论述了面临三维打印时代的到来,未来工业设计领域在设计观念、设计过程和设计结果等方面的新变化,并在此基础上提出为应对这种发展趋势,工业设计师必须具备的新观念、新能力和新的知识构架。     

Effect of Alloying Element on Process Control of High Strength Hot-Rolled Dual Phase Steel

Microstructure evolution of C-Si-Mn-Nb,C-Si-Mn-Cr-Nb and C-Si-Mn-Cr-Mo-Nb tested steels during step-cooling process were studied.Effects of alloying element and process data on microstructure and mechanical properties of high strength Nb bearing DP steel were analyzed,to illustrate the relationship between alloy composition design and process control stability during DP microstructure and property control.It is shown that,700MPa ferrite and martensite DP steel is obtained respectively by three kinds of composition tested steel under different step-cooling process.C-Si-Mn-Nb steel with simple alloying design of low cost is provided with low hardenability,and has strong process sensibility during microstructure evolution.DP microstructure of ferrite and martensite of C-Si-Mn-Nb steel just can be obtained by coiling at low temperature of 250℃.The process control stability of C-Si-Mn-Cr-Nb steel is stronger than that of C-Si-Mn-Nb steel,to obtain DP microstructure by coiling at low temperature.C-Si-Mn-Cr-Mo-Nb steel with complex alloying design of high cost is provided with excellent process control stability.Alloy element Mo can promote stabilizing of metastable austenite to obtain F+M DP microstructure by coiling at medium temperature of 600℃.     

基于ARM-WinCE平台的时钟同步设计

时钟同步是分布式系统的核心技术之一,为实现基于ARM-WinCE嵌入式系统平台的测试仪器组建分布式测试系统,在介绍IEEE1588精确时钟协议基本原理的基础上,提出了使用具有IEEE1588协议硬件支持功能的DP83640以太网物理层收发器在基于ARM-WinCE的嵌入式系统平台上实现时钟同步的设计方案,给出了硬件设计的接口电路和软件设计框架。经测试该方案可达到不低于1μs的同步精度。     

基于TMS320DM642的硬件实现IEEE1588时钟同步

采用美国国家半导体公司推出的专用集成有IEEE1588精准时钟协议硬件支持功能的以太网收发芯片DP83640,通过在物理层标记PTP时钟同步报文发送和到达的时刻,与TI公司的内置以太网媒体接入控制器(MAC)功能的TMS320DM642芯片连接实现高精度的时钟同步功能。     

PLC软冗余技术在监控系统中的应用

冗余功能是一个工业控制网络系统成功的关键环节,是保证系统稳定、安全、可靠的重要手段。文章在西门子S7-300软冗余系统工作原理的基础上,提出了软冗余系统的硬件组成及程序实现方法,通过电源模块、CPU、冗余模块、通信模块以及I／O等相关硬件,完成相应的软件组态。