Monitoring neuronal oscillations and signal transmission betweencortical regions using time-frequency analysis ofelectroencephalographic activity

Oscillatory states in the electroencephalogram (EEG) reflect the rhythmic synchronous activity in large networks of neurons. Time-frequency (TF) methods, which quantify the spectral content of the EEG as a function of time, are well suited as tools for the study of spontaneous and induced changes in oscillatory states. The use of these methods provides insights into the temporal dynamics of EEG activity in both humans and experimental animals, and aids the study of the neuronal mechanisms that generate rhythmic EEG activity. Further the use of TF coherence analysts, which quantifies the consistency of phase relationships in multichannel EEG recordings, may contribute to the understanding of signal transmission between neuronal populations in different parts of the brain. We have used TF techniques to analyze the flow of activity patterns between two strongly connected brain structures: the entorhinal cortex and the hippocampus. Both of these structures are believed to be involved in information storage. By applying various frequencies of stimulation, we have found a peak in the spectral power in both sites at around 18 Hz, but the coherence between the EEG signals recorded from these sites was found to increase monotonically up to about 35 Hz. We have also found that long-term potentiation, a strong increase in the efficacy of excitatory synapses between these sites, either had no effect or decreased coherence     

新型显示器件进展

介绍了有源（光发射）和无源（光反射）显示器件－气体－电子－荧光粉显示，冷阴极场致发射矩阵平板显示、电泳成像显示和电化学显示器件等的发展情况。     

智能结构系统中的光纤传感技术

智能结构系统具有类似人体运动控制功能，埋置在工程结构或材料中便能获得顺应环境变化的自判断性、自适应性、自诊断性、自修复性等诸多性能。这一神奇的科学技术具有重大科学意义和广阔的应用前景。利用特性优良的光纤传感器可以构成一种特殊的光纤智能结构系统。本文较深入介绍适合智能结构系统的光纤多点式和分布式传感技术的原理、结构和实施方法。     

温度,压力对漂移室气体增益的影响

研究了温度及气体压力对漂移室（工作于正比区）气体放大倍数的影响，温度和气体压力的变化范围分别是５￣４０℃及９０￣１０５ｋＰａ。用实验数据拟合得到了函数关系并测量了几种饱和度下函数中的参数值。     

筒形件反旋工艺塑性流动刚塑性有限元分析

建立了筒形件反旋工艺平面变形刚塑性有限元分析的力学模型，比较了把反旋工艺视为正挤和本文力学模型条件下的速度场，有限元分析结果与反旋实际条件相符。     

高强度低密度大模量菲晶态Ai—Li合金

利用单辊快速凝固装置制备出高强度、低密度、大楼量的非晶态Ａｌ６１Ｌｉ２．５Ｙ２５Ｎｉ１１．５（ｗｔ－％）合金，其最大拉伸断裂强度、显微硬度和弹性模量分别为１０３９ＭＰａ、４８８ＤＰＮ和９８．７ＧＰａ．与同成分的晶态合金相比，具有较高的电极电位、较宽的电压钝化区，其腐蚀抗力为晶态合金的７倍．在恒加热速率的晶化过程中出现４个晶化峰，晶化激活能的计算表明，Ａｌ６１Ｌｉ２．５Ｙ２５Ｎｉ１１．５非晶合金的晶化过程为一级反应．     

逻辑与数据库技术概论

本文对二十余年来人们在逻辑与数据库相结合领域所作的工作进行了归纳总结,并把它们区分为三类:理论和完全关系结构方法,纯理论方法以及理论和不完全关系结构方法。本文简要介绍了这三种方法的基本思想和关键技术,并讨论了它们各自的特点和适用范围。     

地方时与区时在电离层研究中的差异

本文指出混淆地时与区时两个时间概念在电离层研究中带来的差异的严重性，建议使用地方与区时这两个名词，而抛弃“本地时”和“当地时”等容易引起混淆的名词。     

介绍两种原皮防腐方法

本文简要地介绍了美国一家公司提供的原皮防腐方法。