The phrase "amount is constant" is correct and usable in written English.
It can be used in contexts where you want to indicate that a specific quantity does not change over time or under certain conditions.
Example: "In this experiment, we assume that the amount is constant throughout the duration of the study."
Alternatives: "quantity remains unchanged" or "value is fixed."
The HGO amount was constant (2.00 g) in all experiments.
While the proportion of patients reporting the payment of informal consultation fees to providers and their amount were constant over time, the proportion of patients reporting expenditures for drugs has increased, and the median amounts have doubled from 5.3 US$ to 10.7 US$.
However, in a certain forest their amounts are constant.
The values of imported Cr amounts for 20 min incubation at 37 °C were used for determining the initial rates since the import amounts are constant within 20 min. The Vmax and Km were calculated with Excel.
Assuming both A and AX have the same diffusion coefficient (k da) and adding the equations for A and AX we have (A25) This shows that the total amount of A at any location satisfies the diffusion equation, and in particular if the total amount of A is constant at every location initially, then this remains so in the subsequent dynamics.
We assume that the total amount of Smad is constant.
For the gene expression microarray analysis, data are generally normalized under an assumption that the total amount of mRNA is constant between different samples.
In a stochastic clock the probability of a certain amount of change is constant (for example, a given quantity of atoms of radium-226 is expected, through decay, to be reduced by half in 1,620 years), although some variation occurs in the actual amount of change.
In the huge oceanic volume the amount of uranium is constant, regulated by its river input (soluble) and balanced by its scavenging (particulate) on the sea floor.
