期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
一种基于fMRI激活实验数据分析的新方法
1
作者 雷震 胡德文 +1 位作者 朱文珍 夏黎明 《中国医学物理学杂志》 CSCD 2002年第2期85-87,112,共4页
多种有关用统计学原理来分析fMRI数据这方面的方法已经被提出,并且得到了广泛的应用。这些分析方法的目的是为了产生一幅图像以用于确定任务相关的显著信号变化区。本文提出了一种控制—参考—频率法,该方法通过对时间序列的谱密度进行... 多种有关用统计学原理来分析fMRI数据这方面的方法已经被提出,并且得到了广泛的应用。这些分析方法的目的是为了产生一幅图像以用于确定任务相关的显著信号变化区。本文提出了一种控制—参考—频率法,该方法通过对时间序列的谱密度进行非参数估计来测试任务频率和血液动力学响应之间的关系,从而达到激活区定位的目的。之后本文通过分析同一组fMRI数据将这种方法和统计参数映射法和相关法进行了比较。实验结果证明了本文所提出的方法在探测由于运动任务所产生的激活区方面是有效的。该方法非常适合探测刺激任务是以周期序列的形式产生时的激活区。 展开更多
关键词 FMRI 激活实验 数据分析 功能磁共振成像 统计参数映射 设计矩阵 控制-参考-频率 大脑皮层
下载PDF
Advance Electronic Load Controller for Micro Hydro Power Plant
2
作者 Dipesh Shrestha Ankit Babu Rajbanshi Kushal Shrestha Indraman Tamrakar 《Journal of Energy and Power Engineering》 2014年第10期1802-1810,共9页
Most of the MHP (micro hydro power) plants use ELC (electronic load controller) for speed control. Various types of ELC have been developed so far. A dummy ballast load is connected across each phase of generator ... Most of the MHP (micro hydro power) plants use ELC (electronic load controller) for speed control. Various types of ELC have been developed so far. A dummy ballast load is connected across each phase of generator terminals and ELC controls the power consumed by the ballast load to result in constant speed operation. The ELC developed so far uses thyristor switches in each phase to control ballast load power. The ELC senses the system frequency and comparing it with reference frequency, it generates a common value of firing angle for all three thyristor pairs of each phase. The performance of such ELC is not perfect for unbalanced consumers load connected in each phase, which overloads the generator. This paper presents an advanced type of ELC which senses frequency as well as consumer's load current of each phase and fires the thyristor pairs with different value of firing angles for different phases. This solves the problem of overloading of the generator with unbalanced consumer's load. Simutink model is developed to perform transient analysis of the proposed scheme and the prototype of hardware is also fabricated. The simulation results and experimental results are presented. 展开更多
关键词 MHP ELC current balancing thyristor.
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部