基于DMA的数据采集系统

DMA控制器使I／O口和主存储器之间的数据直接进行读写，无需CPU的干预，系统总线由DMAC控制。由于数据不要经过CPU的中转，因此数据传送速度很高。设计基于DMA原理的数据采集系统；5-DMAC的控制下，A／D转换器的蛄果直接存入PC的主存储器；A／D的周期性启动采用定时器输出的方波自动控制，方波的频率可以根据A／D转换器的转换速度设置，提高了整个系统的工作效率。根据同样原理，可以设计出高速的数据采集系统。     

LBS在监外服刑中的应用

移动位置服务在未来几年内将成为移动运营商的主要增值手段,中国联通今年将在CDMA1x网络中启动gpsOne定位业务。通过分析比较各种定位技术,根据监外服刑监管系统的要求,提出采用中国联通的CDMA1x网络和gpsOne定位平台来进行数据传输和位置跟踪的监管系统整体解决方案,并在系统架构、电子镣铐的软硬件设计等方面进行了初步的探讨。     

DMA控制器在DSP数据采集系统中的应用

DMA控制器可以无需CPU介入而在内部存储器、外部存储器和芯片外设之间传送数据,其在DSP系统中有广泛的应用价值.基于以DSP芯片TMS320VC5509为核心的数据采集处理系统,通过对FIFO、SDRAM和TMS320VC5509 DMA控制器的介绍,分别给出了具体的接口电路硬件设计和实际软件的代码示例.     

含能粘弹体的动态力学性能与极限力学性能的关系研究

对动态力学性能与极限力学性能 (抗拉或抗压性能 )之间的关系进行了推导 ,提出了利用它们之间的关系由动态参量来预估极限力学性能的关系式 ,并以MC 1为例 ,证明了储能模量E’与抗压强度σb 之间的关系。     

The thermal decomposition studies of three Polish bituminous coking coals and their blends

The objective of this work was to investigate the thermal decomposition of various bituminous coal blends. Three Polish coals of varying rank (82.7, 86.2 and 88.7 wt.% carbon content) and caking ability (weak, moderate and strong) were collected from the Krupiński, Szczygłowice and Zofiówka mines, respectively. These coals were used to prepare binary and ternary blends. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were used. The weight loss and heat flow during pyrolysis, and storage/loss elastic modulus measured as a function of increasing temperature were related to the caking ability of coals. Parameters determined with the TGA and the DSC methods in the binary and ternary blends were correlated with the proportion of strongly-caking-coal concentration in the blend. The weight loss of coal blends was found to be additive parameter. The DSC thermograms of binary blends were found to be different from those of the ternary blends, which suggests a different course for this blend pyrolysis.