High levels of extracellular glutamate are present in retina during neonatal development

The three major classes of neurons which comprise the primary visual pathway in retina are glutamatergic. These cells are generated in two separate developmental stages, with one subclass of photoreceptors (cones) and ganglion cells generated before birth; and the other subclass of photoreceptors (rods) and bipolar cells generated during the first week after birth. Gas chromatography/mass spectroscopy analysis coupled with a new method for collecting small samples of extracellular fluids from retina were used to determine the levels of endogenous glutamate present during differentiation and synaptogenesis of these different cell types. As expected the total retinal content of glutamate increased during the postnatal period in synchrony with the generation and maturation of glutamatergic cells. However, a significant proportion of the endogenous pool was found extracellularly at birth. Intracellular glutamate is localized within cell bodies and growing processes of cones and ganglion cells at this time but few glutamatergic synapses are present. The extracellular concentration of glutamate actually declined during the most active period of synaptogenesis, reaching very low levels in the adult. The high concentrations of extracellular glutamate in neonatal retina could play an important role in a variety of developmental events such as dendritic pruning, programmed cell death and neurite sprouting.     

基于测后模拟原理的半波长输电线路暂态量纵联保护

针对特高压半波长超长的输电距离带来的继电保护难题,提出基于测后模拟原理的半波长输电线路暂态量纵联保护方法.特高压半波长交流输电具有传输距离远、输送容量大、全线无功自平衡等优点,可以作为未来清洁能源电力输送的一种可选方案.通过分析现有输电线路保护方法对于半波长交流输电线路的不适用性,对特高压半波长输电线路在区内外故障情况...     

红外测温技术在氧化锌避雷器故障诊断中的应用

发热是电力设备最典型的故障特征之一,借助红外测温技术能够有效诊断变电站内部电力设备的早期缺陷.近几年来,孝感供电公司将红外测温技术应用于设备的状态检修,效果显著,先后发现了多起设备的严重缺陷.重点介绍一起220 kV氧化锌避雷器(MOA)异常红外测温结果的详细处理情况.对该MOA的带电检测、停电试验以及解体检查与分析表明,通过红外测温与阻性电流测量可及时、准确发现MOA受潮故障,提高了MOA的工作可靠性.     

大时滞系统的智能控制研究

在实际控制应用中常常有大时滞存在，用传统控制方法较难获得满意的控制效果。为解决这个问题，该文提出了基于模糊神经网络控制器，模拟手动控制过程，根据过程状态的动态变化实施控制器的在线调整，仿真和实践结果均表明了该控制方案的优越性。     

基于无线通信技术的路灯监控系统设计

结合合肥市经开区路灯监控系统工程,介绍了一种基于PLC与GPRS的无线路灯监控系统的设计,对该系统的组成构架及其功能作了详细说明。     

配电网网格化自动成图的实现

为给调控员的调控运行工作提供良好的人机界面,实现无人干预或者少人干预的图形维护工作,提出了网格化的自动成图概念。文中主要介绍了网格化自动成图的实现方法及应用效果,先是给出了系统的总体框架,然后详细介绍了模型抽取、节点布局和图形布线三项自动成图的基本过程,同时针对各种类型的图形成图作了相关阐述,并以单线图、系统联络图为例分别叙述了树状层次布局、边界层次布局算法及通道轨道布线算法的具体应用情况,最后展示了网格化自动成图的应用效果。