The overall effect of temperature gradients is stressed for the Earth's core and surface, but also for the Sun's surface. Using Rayleigh–Bénard convection in helium and mercury, we measured all of the scaling properties of the period-doubling cascade and quasiperiodicity. Hard turbulence scaling properties are presented in an experiment using helium gas at low temperature. A [Formula: see text] scaling law is measured and also an exponential distribution for temperature fluctuations is observed. We present a study of a Rayleigh–Bénard convection cell with an open top and a floater. One of the simplest limit cycles is observed for the floater position. It follows a model proposed by Wilson for continent motion. Using the Soret effect, we study how temperature differences lead to strong accumulation of DNA suspensions. Also using polyethylene glycol concentration gradients, we measured local DNA and RNA accumulation. Finally, using thermal convection, we build one of the smallest PCR machines.

中文翻译：

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非线性动力学之旅：温度梯度的情况


温度梯度的整体影响对地核和表面以及太阳表面都造成了压力。使用氦和汞中的 Rayleigh-Bénard 对流，我们测量了周期倍增级联和准周期性的所有缩放特性。在低温下使用氦气的实验中提出了硬湍流结垢特性。测量了 [公式：见正文] 缩放定律，并观察到温度波动的指数分布。我们提出了一个关于具有开口顶部和浮子的 Rayleigh-Bénard 对流单元的研究。最简单的极限循环之一是浮动位置。它遵循 Wilson 提出的大陆运动模型。利用 Soret 效应，我们研究了温差如何导致 DNA 悬液的强烈积累。同样使用聚乙二醇浓度梯度，我们测量了局部 DNA 和 RNA 积累。最后，使用热对流，我们构建了最小的 PCR 机器之一。