"direct proportionality" is an appropriate and usable term in written English.
You can use it to refer to the relationship between two variables that increase or decrease at the same rate. For example, "The amount of time spent studying is in direct proportionality to the success of the exam."
It can be deduced that there must exist a direct proportionality between the rate of reaction and the concentration of the reacting species and at the same time an exponential proportionality between the rate of reaction and the electrode potential.
There is a linear relationship (i.e., direct proportionality) between the intensity distribution in the image plane and that existing in the object, when the object is illuminated with incoherent light (e.g., sunlight or light from a large thermal source).
Note that there is no direct proportionality between oxygen fugacity and X O fluid.
Several researchers have reported the direct proportionality relation of hardness with wear resistance.
This shows the direct proportionality of multiple features with learning capability for machine learning algorithms.
Fluids that do not exhibit a direct proportionality between shear stress and shear rate are classified as non-Newtonian.
Even at a fine scale average LD was very low with consequent impacts on power to detect untyped causal variants via LD with typed markers because of the direct inverse proportionality between r2 and sample size in association analyses.
Often the relation was one of proportionality, as, for example, when the price level rose in direct proportion to an increase in money.
For simplicity, we assume that the proportionality is direct (see section 3 in supporting information S1 for details about this assumption).
In the second case, it is worth mentioning that even though the proportionality is a direct consequence of force balance and a visco-contractile rheology, it hadn't been verified before, to the best of our knowledge.
The bandgap energy was estimated by using Equation (1) 1 where α is the absorption coefficient, hν the photon energy (h is Planck's constant, ν is the frequency), n a constant with a value of 2 for direct-bandgap semiconductors, A a proportionality constant related to the material, and Eg the bandgap energy.
