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Two Experiments in Dissipative Systems of Many Degrees of Freedom

多自由度耗散系统的两个实验

基本信息

批准号：
09440146
负责人：
SANO Masaki
金额：
$ 7.55万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

项目摘要

We chose two typical experiments from Dissipative Systems with many degrees of freedom.The one is an experiment on developed thermal turbulence in a closed cell. The second is cultured neuron network in vitro.1. Developed thermal turbulence is created in Rayleigh-Benard configuration by using a low Prandtl number fluid, mercury. Achieved Rayleigh number (Ra) is 10^<11> and Reynolds number of the box is 5x which is the highest value among ever existing laboratory experiments for low Prandtl number fluid and compatible with the highest one for other fluid. We found a new state in thermal turbulence in which two boundary layers are inverted, i.e. viscous boundary layer is totally included within thermal boundary layer. In spite of this inversion, net heat transport across the cell (Nusselt number, Nu) was found to be proportional to Ra^<0.29> which contradicts to the theoretical prediction that Nu is proportional to Ra^<1/2> when two boundary layers are inverted. We concluded that the observed state is the asymptotic state of thermal turbulence.2. We made cultures of neurons from 1 8days rat embryos. Network of neurons are regenerated on a glass substrate. By using Ca sensitive fluorescent dye and confocal microscope, dynamics of Ca concentration activity in neurons are measured and analyzed. We found three types of synchronous firing of neural network ; (1) Periodic (2)Non-periodic (3) Propagating synfiring pattern. We also proposed a new way of analyzing multi-point time series of neural activities. It enabled us to identify different clusters of neurons firing with different synchronous modes.

我们从耗散系统中选择了两个典型的多自由度实验。第一个是在封闭单元中产生热湍流的实验。二是体外培养神经元网络。 1．通过使用低普朗特数流体汞，在瑞利-贝纳德配置中产生发达的热湍流。箱体达到的瑞利数(Ra)为10^<11>，雷诺数为5x，是现有低普朗特数流体实验室实验中的最高值，并与其他流体的最高值兼容。我们发现了热湍流的一种新状态，其中两个边界层是倒置的，即粘性边界层完全包含在热边界层内。尽管存在这种反演，但发现穿过电池的净热传输（努塞尔数，Nu）与 Ra^<0.29> 成正比，这与当两个边界层反转时 Nu 与 Ra^<1/2> 成正比的理论预测相矛盾。我们得出结论：观测到的状态是热湍流的渐近状态。 2．我们从 1 个 8 天的大鼠胚胎中培养了神经元。神经元网络在玻璃基板上再生。利用Ca敏感荧光染料和共聚焦显微镜，测量和分析神经元中Ca浓度活性的动态。我们发现了神经网络同步触发的三种类型； (1) 周期性 (2) 非周期性 (3) 传播同步点火模式。我们还提出了一种分析神经活动多点时间序列的新方法。它使我们能够识别以不同同步模式放电的不同神经元簇。