gradient freeze growth apparatus

例句：

1. 1. The temperature gradient between the two regions is quite significant.
   这两个地区之间的温度梯度相当显著。
2. 2. The chemical reaction follows a gradient of concentration.
   化学反应遵循浓度的梯度。
3. 3.The path follows a gentle gradient up the mountain.
   这条路线沿着山丘缓缓上升。