The influence of gravity (including 0 G, 0.16 G, 0.38 G, 1 G and 1.8 G) on the antisolvent crystallization of L-histidine was investigated in a self-designed micro-channel crystallizer on a zero-G flight, which was successfully launched on June 13th, 2018. The stable form of L-histidine was obtained under microgravity, while only the metastable form can be observed in the ground experiments with the same inlet conditions. The possible reason is the extremely ordered flow field of the system in microgravity environment. A large amount of small particles aggregated at 1.8 G due to the enhanced micromixing, which favors nucleation. Bigger particles crystalized at Moon gravity (0.16 G) without the excessive consumption of the supersaturation by explosive nucleation and with moderate convection of the system. It is concluded that both nucleation and crystal growth were influenced by the micromixing status in the system due to the altered gravity extent.

中文翻译：

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微重力作用下微通道反应器中L-组氨酸的反溶剂结晶

在自行设计的微通道结晶器中以零重力飞行研究了重力（包括0 G，0.16 G，0.38 G，1 G和1.8 G）对L-组氨酸反溶剂结晶的影响，并成功地对其进行了研究。于2018年6月13日推出。L的稳定形式-组氨酸是在微重力下获得的，而在地面实验中，在相同入口条件下只能观察到亚稳形式。可能的原因是在微重力环境下系统的流场极为有序。由于增强的微混合，大量小颗粒在1.8 G处聚集，这有利于成核。在月球重力（0.16 G）下，较大的颗粒结晶，而不会因爆炸形核而过度消耗过饱和度，并且系统的对流程度适中。结论是，由于重力程度的改变，成核和晶体生长都受系统中微混合状态的影响。