线性代数网上学习系统的开发与研究

本文简要介绍线性代数学习网站的系统研究与开发设计．涉及到网络数据库、ASP、界面设计等多种技术.该线性代数网上学习系统为老师和学生提供了交流平台，其界面美观、操作简便．具有良好的应用前景.     

Evaluation of the stability and analysis of halogenated furanones in disinfected drinking waters

A refined method for the sub-nanomolar analysis of 13 halogenated furanones in chlorinated drinking water is proposed which uses liquid-liquid extraction, methylation where necessary, gas chromatographic separation, and either micro-electron capture or ion trap mass spectrometric detection. Liquid-liquid extraction with methyl tert-butyl ether was demonstrated to be effective for recovery of halogenated furanones. Confirmation of the halogenated furanones identity and reduction of natural organic matter interference were achieved by ion trap tandem mass spectrometry. Compound stabilities and procedural efficiencies were evaluated to permit optimization of the method for reasonable sample volumes and a 1000:1 pre-concentration factor that would permit feasible sample collection in the field. Both chlorinated and brominated analogues of MX (3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone) were included in a suite of compounds targeted in a national occurrence study of disinfection by-products.     

基于i.MX35的工程机械显示终端设计

工程机械显示终端是重要的人机交互界面,随着工程机械控制系统信息化和智能化水平的不断提高,对车载显示终端也提出了越来越高的要求。为了满足需求,研制了基于i.MX35的工程机械显示终端,该显示终端以i.MX35多媒体应用处理器为核心,采用CODESYS作为应用编程平台,实现了人机界面显示、CAN总线通信、摄像头视频采集、大容量数据存储等功能,具有显示性能强大、启动速度快、应用编程灵活、易于扩展等特点,可以广泛应用于各种工程机械控制系统中。     

基于i.MX35的挖掘机视频监控系统设计

挖掘机等工程机械需要对施工现场的视觉盲区进行视频监控,确保作业安全.为了满足安全需求,研制了基于i.MX35的挖掘机视频监控系统,使用i.MX35作为视频主处理器、ADV7180作为NTSC/PAL摄像头输出视频的解码芯片、eMMC或PATA接口固态硬盘作为视频存储介质,实现对挖掘机等工程机械作业现场的视频监控、记录与回放等功能,能够显著提高生产效率、保证作业安全,可以广泛应用于挖掘机等工程机械的控制系统中.     

一种开源嵌入式Linux集成开发环境定制

嵌入式软件交叉编译和调试环境要求编辑和编译软件在主机上进行,编译好的软件在目标机上运行,同时,主机和目标机建立起通信连接,并传输调试命令和数据。首先介绍了一种以GNU工具链为核心的开源嵌入式集成开发环境Eclipse/Target Builder/Esto系统,然后讨论了其结构框架和功能,最后以Motorola M9328MX1ADS开发板为例,详细介绍了构建Eclipse/Target Builder/Esto开发环境的具体方法以及为开发板定制BSP(板极支持包)的过程。     

基于i.MX27的无线视频监控系统的设计与实现

介绍了一种以i.MX27为硬件平台的处理器,嵌入式Linux为操作系统的无线视频监控系统的实现方案.给出了系统的总体结构与软硬件模块,重点阐述了视频采集及编码的过程;针对i.MX27硬件编码单元输出的H.264视频流,设计并实现了在RTP协议下视频流的实时传输.客户端通过接收、解码及显示监控前端传送的H.264视频流,实时显示监控场景.经实验测试,该系统达到了较好的实时性和可靠性.     

EBoot下USB下载功能的实现

在基于WinCE构建的嵌入式系统中EBoot下载功能尤为重要。EBoot原始方案中具有网口与串口下载的实现而缺乏通过USB进行下载的功能。在USB功能单元层次上提出一种数据传输协议,并基于此协议在SEP5010嵌入式平台上实现EBoot下的USB数据传输,从而实现EBoot对USB下载功能的支持。实验结果表明,该方案可以达到799 kB/s的数据平均传输速度,在不增加额外电路的前提下实现了SEP5010平台上EBoot的USB数据下载功能。     

Electronic structures and chemical bonding in diatomic ScX to ZnX (X = S, Se, Te)

Bond distances, vibrational frequencies, electron affinities, ionization potentials, dissociation energies, and dipole moments of the title molecules in neutral, positively, and negatively charged ions were studied using density functional method. Ground electronic state was assigned for each molecule. The bonding patterns were analyzed and compared with both the available data and across the series. It was found that, besides ionic component, covalent bonds are formed between the metal s, d orbitals, and the p orbital of S, Se, and Te. For neutral and cationic molecules, the covalent character increases from ScX to CrX and from FeX to CuX with an exception of decrease at MnX and ZnX, while for anionic molecules, the trend is not obvious. For both neutral and charged molecules, the sulfides have the shortest bond distance and largest vibrational frequency, while tellurides have the largest bond distance and smallest vibrational frequency. For neutral and anionic molecules, the dissociation energy of sulfides is the largest, that of tellurides is the smallest, while this only remains true for cationic molecules from ScX(+) to FeX(+).     

New derivatization method for determination of 3-chloro-4(dichloromethyl)-5-hydroxy-2(5H)-furanone in water

An extremely potent mutagen, 3-chloro-4(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) is commonly present in chlorinated drinking water. Due to its high mutagenic activity and according to World Health Organization guidelines its concentration should be controlled in drinking waters. Determination of MX is difficult due to ppt levels at which the compound usually exists in drinking waters. Derivatization of MX with 2-propanol is presented as a method which significantly lowers the GC–MS detection level compared to other alcohol derivatization agents.