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

温度梯度的总体影响不仅针对地核和表面，而且也针对太阳表面。利用氦和汞中的瑞利-贝纳德对流，我们测量了倍周期级联和准周期性的所有标度特性。在低温下使用氦气的实验中展示了硬湍流缩放特性。测量了[公式：见文本]比例定律，并且还观察到了温度波动的指数分布。我们提出了一项对具有开放顶部和浮子的瑞利-贝纳德对流室的研究。对于浮子位置观察到最简单的极限环之一。它遵循威尔逊提出的大陆运动模型。利用 Soret 效应，我们研究了温度差异如何导致 DNA 悬浮液的强烈积累。我们还使用聚乙二醇浓度梯度测量了局部 DNA 和 RNA 积累。最后，利用热对流，我们建造了最小的 PCR 机器之一。