An experimental study on the correlation between the behavioral evidences of sequence learning and ERP effects

研究序列学习行为学习表现的脑电特征。实验中,被试对一12元素长的二阶序列进行反应任务,同时记录其脑电信号,序列中随机出现不符合序列规则的异常刺激。实验结果表明,标准刺激的反应时相对异常刺激逐渐减小,这一反应时受益即为被试学习到序列知识的行为表现。根据反应时受益程度将序列组块分类为习得组块与未习得组块后,对习得组块,异常刺激在学习前、后半段均引起了更大的N200成分,未习得组块则无此效应。实验结果说明:①序列学习的习得行为表现存在一定组块效应。②ERP波形能够体现出与习得行为表现相关的神经活动。③对习得组块,有可能学习早期即进行了一定特异的加工处理

A new technique of rehabilitation training based on motor imagine using brain computer interface-func-tional electric stimulation system and it＇s effect on plasticity of brain of a stroke patient

目的:验证脑机接口结合功能性电刺激(BCI-FES)在中枢神经康复中的可行性及其机制。方法:对1例40岁男性脑卒中后左侧上肢重度瘫痪患者进行4周的基于运动想象的BCI-FES训练,训练前后各进行一次系统上肢功能评价及包含"运动"及"想象"组块的fMRI检测,进行功能激活图的绘制。结果:经过为期1个月的训练后左手最快抓握速度提高24.7%,左手抓握运动时功能性磁共振成像(fMRI)激活表现为出现病灶同侧主要运动区(M1)及辅助运动区(SMA)的激活,病灶对侧M1区及运动前区(PMC)激活较训练前减弱。左手运动想象任务时出现了双侧SMA及病灶同侧右后顶叶的激活。结论:脑机交互技术可促进脑卒中患者的中枢神经重塑。BCI-FES应用于存在脑损伤的脑卒中患者的康复训练是可行的。Objective： To study the feasibility of brain computer interface combined with functional electric stimulation （BC1-FES） applied to a patient with stroke as a new rehabilitation training system and to explore its mechanism. Method： The participant was a 40 years old man with severe left-hand paralysis after stroke. He received 4 weeks training with BCI-FES system based on motor imagine. The motor function of upper limb was assessed and fMRI examination was conducted pre- and after training. Result： Maximum grasp-relax speed of affected hand increased by 24.7% after training. When motion task was executed the activations in primary motor area（M1） and supplement motor area（$MA） of ipsilateral hemisphere were observed with fMRI after training, and eontralateral activations in M1 and premotor eortex（PMC） decreased in addition. When motor imagine task was executed, the activations transferred to bilateral SMA and ipsilateral posterior parietal after BCI training. Conclusion： BCI-FES was a kind of feasible rehabilitation therapy for stroke survivor. The mechanism of func- tional recovery by using BCI-FES was to promote the plasticity of central nervous system

The physical characteristic study on luminance uniformity and temperature for power GaN LEDs chip

基于电流连续方程、欧姆定律及定性三维热流传导模型研究发光二极管(lEd)芯片的电流密度分布、热量、温度之间的相互交叉关系,进而测试分析gAn基蓝光lEd电流扩展效应和亮度分布的关系,认为芯片亮度变化趋势可作为判别电流扩展性能的有效手段.由于芯片表面温度、亮度分布和电流密度之间存在紧密的联结关系,通过测试芯片表面温度或亮度分布就可定性了解器件电流扩展性能,从而为优化电极结构提供一种判定依据.在不同电流和热沉温度下,进一步讨论了电流密度非均匀性和亮度分布的关系,电流密度拥挤将导致芯片局部区域热量堆积,非辐射复合作用增强,限制出射光子数目,因此热量是影响亮度分布的重要因素之一.通过载流子传输机理进一步说明温度影响亮度均匀性的原因,并通过实验说明理论分析的可行性.通过优化电极结构能改善器件的电流扩展效应以及亮度均匀性,对提高大功率lEd的可靠性具有重要作用.In this paper,we study the relationship among current density distribution,heat and temperature based on current continuity equation,ohm law and three-dimensional heat transfer model.The relationship between luminance distribution and current spreading of GaN blue light emitting diode(LED) is studied.Luminance distribution is proved to be an effective method of distinguishing the performance of current spreading.Because of the close relationship among temperature,luminance distribution and current density, a qualitative method of optimizing electrode structure and current spreading is proposed.With different currents and heat sink temperatures, the current non-uniformity and the luminance distribution of LED are analyzed.Temperature or current density crowding results in heat accumulation,increase of non-radiative recombination and the restriction of the emitting photons,hence thermal flux is an important factor influencing the luminance distribution.Through carrier transport mechanism,the reason for the temperature influence on luminance distribution is explained.Optimized contact electrode structure can improve current spreading and luminance uniformity,also considerably increase the reliability of high power LED.福建省科技计划重点项目(批准号:2011H0021;2012H0039);福建省科技项目(批准号:2011H6025);福建省自然科学基金(批准号:2011J05162);福建省教育厅A类科技项目(批准号:JA11175);漳州师范学院科学研究资助项目(批准号:SJ1017)资助的课题---