基于DSP2808的轴流风机控制器设计

针对工业用轴流风机,设计了基于DSP2808的智能轴流风机控制器,给出了DSP系统、CPLD系统、驱动电路、功率电路、故障检测与保护电路、单端反激变换器的设计方案;分析了风机调节流量的方法,控制器能够根据温度反馈通过PWM斩波实现风机宽范围无级调速,实现节能;控制器能够接收外部电位计、温度传感器、485总线的转速给定,表决后产生最终的转速给定;控制器具备电机绕组过热、IGBT过热、交流侧过欠压、直流侧过欠压、直流侧过流等故障检测与保护功能;实验结果表明:控制器能够实现风机匀加速软起动及起动与转速闭环之间的平稳过渡,有效降低了风机启动、运行过程的噪声,同时实现了节能.     

北斗定位系统在飞行试验中的应用研究

为了解决使用美国商用GPS对我国飞行试验中定位精度和速度的种种限制以及对我国国防安全的潜在危险,文章基于我国日趋成熟自主研发的北斗定位系统技术,开展其在飞行试验中的研究;文中分别对北斗的短报文通信技术、单点及事后差分技术、实时差分技术在飞行试验中的应用方法进行研究,并介绍了飞行试验中北斗定位数据的处理方法;通过试验数据与美国商用GPS数据进行对比,结果显示北斗定位系统精度与美国商用GPS精度接近;最后展望了北斗定位系统未来在我国飞行试验以及国防、科研以及交通运输等民用领域的广阔应用前景.     

过程控制系统中多条件约束的多传感器故障检测与诊断

针对工业过程控制系统中的故障具有类型多样、时空独立和非线性等特点,使得检测与诊断效率降低,系统性能下降等问题,提出了一种基于自定义多条件约束的多传感器故障检测与诊断机制;该机制,首先考虑了系统的稳态和时空特征建立了非线性过程控制系统多故障模型,并给出了满足条件判定法则;然后对于系统中的单故障,并发故障和通信故障等类型给出了多条件约束法则及独立特性判断;最后提出了通过自定义多条件约束的多传感器故障检测与诊断机制;实验结果表明,在平均检测概率、稳态特征保持能力和系统功耗等方面明显优于无条件约束的机制,可以显著改善过程控制系统性能.     

Dual Verbal Elicitation: The Complementary Use of Concurrent and Retrospective Reporting Within a Usability Test

Verbal protocols are the primary tool for understanding users' task-solving behaviors during usability testing. A qualitative study that examined the utility of combining a concurrent and retrospective think-aloud within the same usability test is described. The results indicate that although there was significant overlap between the types of utterances produced during each think-aloud, the retrospective phase produced more verbalizations that were relevant to usability analysis, for example, helpful self-assessments of performance, yielding insights into the impact of encountered difficulties. However, a small number of less desirable utterance types emerged: hypothesising, rationalizing, and forgetting. When used together, both methods contributed to an understanding of usability issues; the concurrent phase yielded more usability issues overall, and the retrospective data improved the understanding of these by (a) reinforcement: users highlighted the impact of an issue on their experience, (b) elaboration: users would provide causal explanations of encountered difficulties, and (c) context: users provided information about the product's context of use.     

光伏提水技术研究与应用

光伏提水是涉及太阳能采集与变换、电力电子、电机、水泵等多门学科专业综合配套的一门新兴技术,因其符合新能源战略发展的需要而备受关注和重视。基于研究和推广应用需要,在回顾了光伏提水技术发展历程的基础上,介绍了近年国内出现的几种有代表性的光伏提水装置,对它们的类型和系统结构进行了分析,探讨了光伏提水技术在我国特别是西部干旱缺水地区推广应用的前景和价值。     

水电站半地下厂房结构抗震设计方案比选

赤道几内亚吉部洛水电站厂房为半地下式厂房,原设计方案考虑在机组间设永久变形缝,但由于该厂房上游地下水位很高,厂房底部水头超过30 m,所以在上游边墙和楼板的分缝处会出现局部应力和变形过大。为减小应力和变形,另考虑后浇带方案,以增强其整体性。此方案下厂房成为一个整体结构,不存在变形缝,但同时也形成了超过50 m的大跨度混凝土高边墙和楼板结构,超出了厂房设计规范中允许的最大跨度,有必要对其进行论证。采用地震反应谱法并考虑动静叠加,对两方案在设计地震作用下的地震响应作了对比分析。结果表明：后浇带方案不仅能减小厂房局部应力和变形,还能使厂房满足抗震要求,优于原设缝方案。为类似存在高水头压力问题的水电站厂房设计提供可靠参考和借鉴。     

为WinPE系统集成设备驱动的一次尝试

WinPE在启动时会读取TXTSETLTP.SIF内容,用文本安装模式加载第三方驱动.利用这一功能我们可以把驱动封装到WinPE启动系统中.     

基于LPC3250的微型投影系统设计与实现

本系统以高性能ARM9处理器LPC3250为核心,HX88xx为LCOS驱动芯片。HX70xx为LCOS模块,LQ035Q1DG01为LCD模块,建立μC／OS-Ⅱ嵌入式实时操作系统,通过红外控制实现系统在投影仪和LCD之间切换。本文重点阐述了系统主要接口硬件电路的设计和系统软件的实现。实现了寿命长、成本低、可靠性高的便携式微型投影系统的设计。     

基于主动防御模式下蠕虫病毒特征码的提取模型及算法设计

从一般的网络攻击技术出发,分析现有网络安全技术的弱点,采用主动防御的新思想来应对当前反病毒技术远远落后病毒技术发展的局面。重点对基于动态陷阱生成技术的蠕虫病毒特征码的自动提取进行研究,对收集的新型蠕虫病毒特征扩充IDS的特征库,弥补入侵检测系统对未知病毒攻击无法识别问题,完善防御系统。     

Protein profiling of low-density lipoprotein from obese subjects

Although obesity and high levels of low-density lipoprotein (LDL) are well-known risk factors for cardiovascular disease, the precise role(s) of different LDL constituents in obesity has not been explored. In the present study, we compared the LDL proteome of healthy control adults (body mass index<25) and obese subjects (body mass index>30). LDL was isolated by density-gradient ultracentrifugation and proteins were separated with 2-D PAGE, quantified, and identified by peptide mass fingerprinting using MALDI-TOF MS. A new LDL-associated protein was identified as transthyretin and found to be significantly more abundant in LDL from the obese subjects. In addition, LDL from the obese subjects contained relatively more α(1) -antitrypsin, apo J, apo C-II, than LDL from controls, and also more of an acidic isoform (pI/Mr; 5.2/23 100) of apo A-I. On the other hand, the relative amounts of apo A-IV and the major isoform of apo A-I (pI/Mr; 5.3/23 100) were significantly less in LDL from the obese subjects. Apo E was less and non-sialylated apo C-III more abundant in LDL from obese men than control men, while there were no such differences between LDL from obese and control women. These findings illustrate that obesity is not only associated with increased LDL-cholesterol levels but also with alterations in the LDL protein composition. The presence of transthyretin in LDL from obese subjects may reflect over-nutrition and affect the lipid metabolism in obesity.