The phrase "at upper layers of" is correct and usable in written English.
It can be used to describe something that exists or occurs in the higher levels or strata of a system, structure, or organization.
Example: "The analysis focused on the interactions at upper layers of the atmosphere, where weather patterns are formed."
Alternatives: "in higher levels of" or "at the top layers of".
7) In an effort to comply with strict new rules aimed at preventing crime at the upper layers of financial institutions,banks have been clearing house.
Traditional approaches to securing communications rely heavily on the data encryption at the upper layers of the protocol stack.
Both the X-ray diffraction and scanning electron microscopy analyses reveal that the a-axis grains appear at the upper layers of the films when the thickness reaches to 1,030 nm.
This was because the top profile of soil is more acidic than the deep profile and the highest EC values at the upper layers of soils may have been affected due to the decomposition of organic compounds (Nogueirol et al. 2013).
MCMV infection reduced the number of BrdU-labeled cells arriving at the upper layers of the CP in the E18.5 fetal brains, suggesting MCMV infection disturbs the development of the cortical upper layers (Fig. 7D and E).
The mitochondria were segregated to the bottom layers of the gradients (fraction 4 5)–8), as indicated by the presence of VDAC, whereas lysosome-enriched fractions were found mainly at the upper layers of the gradients (fraction 1 4), as shown by the presence of either LAMP1 or cathepsin D (Fig 3A).
Together, these features suggest an ice-rich composition for at least the upper layers of the terrain, which is currently being heavily modified through loss of ice and intense weathering, possibly by wind.
Meanwhile, in high EASMI years, reinforcement of anomalous cyclonic circulations at the lower layer of the troposphere in the western North Pacific and reinforcement of anomalous anticyclonic circulations in the mid-latitudes can be identified through differences in horizontal divergence at the lower and upper layers of the troposphere between the two groups (Fig. 9).
GRASP fluorescence in frontal sections at the lower and upper layers of the ASP (as defined in Figure 1F) confirms this pattern of contacts.
Very small or microscopic animals remain at great depths during the day and rise at dusk, concentrating in the upper layers of water during the night.
