共查询到11条相似文献，搜索用时 78 毫秒
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癫痫是一种常见神经系统疾病,其发病机制尚不完全清楚.研究表明,星形胶质细胞在癫痫发作中起到关键作用,可能作为癫痫治疗的靶点.基于临床癫痫脑电特征,建立相匹配的神经元集群-星形胶质细胞集群耦合模型,有助于癫痫发作机制的进一步研究以及癫痫控制技术的发展.本文基于局灶性癫痫发作动力学模型,考虑星形胶质细胞Ca2+波动与神经元集群发放频率的关系,建立神经元集群-星形胶质细胞群耦合动力学模型,探讨了星形胶质细胞群对癫痫发作动力学行为的影响,并模拟刺激治疗,对局灶性癫痫进行抑制.研究发现：星形胶质细胞群与神经元集群的耦合参数驱动模型表现出三种类型的局灶性癫痫发作模式,其共同特点为星形胶质细胞群的谷氨酸过表达;第一种癫痫放电形式可以通过调节星形胶质细胞群与神经元集群耦合参数进行抑制,而其余两种无法通过参数调节进行抑制;常数刺激可以使三种癫痫放电转变为周期放电,但过大或过小的刺激无法完全抑制第一种癫痫放电;高频、强幅值的方波刺激能够有效抑制三种癫痫放电. 相似文献
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某燃煤电厂烟气脱硫采用石灰石—石膏湿法脱硫工艺。针对在石灰石氧化钙含量测定时发现一批次的石灰石氧化钙含量超标,氧化钙含量高达60%,且折算成碳酸钙含量则大幅超过100%,明显不符合常理的问题。通过一系列的化学分析试验,验证了试验方法、检测试剂、试验过程以及铁铝杂质含量并不是造成氧化钙含量超标的原因。最后通过对检测原理的进一步分析和试验,得出主要原因是石灰石中掺入了生石灰或熟石灰,人为添加钙成分类似于牛奶中添加三聚氰胺,干扰了石灰石中氧化钙的测定。通过定性检测样品的水溶液是否含有钙离子,可快速有效的检测石灰石中是否掺入了生石灰或熟石灰,保证了石灰石的质量验收和脱硫系统的安全运行,很大程度上弥补了国标测定方法《化工用石灰石中氧化钙和氧化镁含量的测定》的不足 相似文献
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在神经元的生理实验中经常观察到丰富的钙振荡模式,本文详细综述了产生这些现象的钙流交换机理和各类通道调节机理,以及描述这些生理机理的数学表达式.介绍三类典型的研究钙振荡的非线性动力学模型,即电压动力学与钙动力学相耦合的模型,多个钙存储单元之间钙流平衡的模型和考虑信使物质IP3的振荡与钙振荡相互作用的模型;并针对第一个模型简要地讨论其复杂的动力学行为;最后对神经元钙振荡的非线性动力学研究提出了一些展望. 相似文献
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本文以具有典型黄土丘陵特征的砖窑沟流域为例,对该流域梁峁地主要土壤类型上不同土地利用方式下0～200cm层土壤剖面CaCO3含量进行了分析。结果表明:土壤CaCO3含量耕地>林地>荒草地;耕地土壤CaCO3有明显的累积层,累积深度约在20～100cm之间;林地累积层深度约在20～60cm之间;而荒草地无明显累积层。这种现象与一般干旱半干旱地区不同。 相似文献
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EEG signal analysis involves multi-frequency non-stationary brain waves from multiple channels. Segmenting these signals, extracting features to obtain the important properties of the signal and classification are key aspects of detecting epileptic seizures. Despite the introduction of several techniques, it is very challenging when multiple EEG channels are involved. When many channels exist, a spatial filter is required to eliminate noise and extract relevant information. This adds a new dimension of complexity to the frequency feature space. In order to stabilize the classifier of the channels, feature selection is very important. Furthermore, and to improve the performance of a classifier, more data is required from EEG channels for complex problems. The increase of such data poses some challenges as it becomes difficult to identify the subject dependent bands when the channels increase. Hence, an automated process is required for such identification.The proposed approach in this work tends to tackle the multiple EEG channels problem by segmenting the EEG signals in the frequency domain based on changing spikes rather than the traditional time based windowing approach. While to reduce the overall dimensionality and preserve the class-dependent features an optimization approach is used. This process of selecting an optimal feature subset is an optimization problem. Thus, we propose an adaptive multi-parent crossover Genetic Algorithm (GA) for optimizing the features used in classifying epileptic seizures. The GA-based approach is used to optimize the various features obtained. It encodes the temporal and spatial filter estimates and optimize the feature selection with respect to the classification error. The classification was done using a Support Vector Machine (SVM).The proposed technique was evaluated using the publicly available epileptic seizure data from the machine learning repository of the UCI center for machine learning and intelligent systems. The proposed approach outperforms other ones and achieved a high level of accuracy. These results, indicate the ability of a multi-parent crossover GA in optimizing the feature selection process in EEG classification. 相似文献
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以棕壤为供试土壤进行施用钙素的盆栽试验结果表明,与对照相比,每公斤土施钙２００ｍｇ和８００ｍｇ时,花生分别增产４５％和５２％;每公斤土施钙２００ｍｇ的处理花生果仁中蛋白质含量较对照增加７．１％,从经济高效施肥观点出发,该处理较好。在花生开花下针期以前,每日单株吸钙量逐渐增加,而生育后期呈下降趋势。在苗期花生植株地上部含有的钙元素占整个植株体的比率较高,开花下针期居中,成熟期偏少一些。 相似文献
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Steffen Hergert Max Linkor Markus Korny Norbert Fruehauf 《Journal of the Society for Information Display》2007,15(6):421-429
Abstract— A calcium measurement setup was built for testing encapsulation especially for OLED applications. This setup is able to measure both reflective and transmissive cells. For the characterization of sealants, a method to compare them with other sealing products will be described. This includes the use of spacers, a homogeneous surface energy, and the geometry of the sealant line. The effects of different geometries will be discussed. The setup was designed to achieve good accuracy at a very reasonable component cost, which will allow other facilities to replicate this setup. Therefore, the construction plan as well as the list of components can be downloaded from our website (Ref. 3). 相似文献
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中国林蛙的某些生理生化指标随季节变化而有所不同,繁殖期是其个体发育的一个特殊时期。本试验对中国林蛙春季繁殖期研究结果表明,其血清钙、钾离子浓度排卵前分别为l23.69±14.9lmg·L-1,4.096±0.200mmol·L-1;排卵后分别为69.37±9.11mg·L-1,2.515±0.178mmol·L-1。这与中国林蛙生殖活动密切相关。 相似文献
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