The phrase "under different periods" is correct and usable in written English.
You can use it when referencing something that has happened or been observed at multiple points in time, such as a person's behavior across different life stages. For example, "John's behavior towards his parents changed drastically under different periods of his life."
But having come under siege during different periods, the Maltese have also shown resilience and defiance of the odds.
In order to obtain different levels of condensates/adsorbates, steel substrates were heated in a vacuum chamber (at 250 torr) and allowed to cool under vacuum for different periods of time, ranging from 1 to 62 h before splat deposition.
To analyse the anatomopathological characteristics of the tumours undergoing LG treatment, mice were killed under anaesthesia after different periods of time.
The regime kept Ms Suu Kyi under house arrest during different periods for a total of 15 years.
Multi-wall carbon nanotubes (MWCNT) were carboxylated by heating MWCNT powder in a mixture of HNO3 and H2SO4 (1:3 v/v) at 70 °C under constant sonication for different periods.
1O2 generation was observed using ABDA (9,10-anthracenediyl-bis methylene dimalonic acid) indicator at pH 7.4 and 5.0 under irradiation and over different periods.
The photocatalytic activity of the samples was determined by assessing the decomposition rate of methylene blue (MB) solutions under UV light for different periods of time.
The products of piperazine-directed synthesis of two-dimensional (2D) aluminophosphates, AP2pip and AlPO-CJ9, that were crystallized under different conditions for different periods of time were freeze-dried and characterized using XRD and NMR techniques.
Based on the Mindlin plate theory and Wiener Hopf technique, a solution for hydroelastic responses of 2D floating plates with hinge connection is presented under the action of different periods of monochromatic incident waves on a fluid of finite depth.
