The phrase "a rather large fraction" is correct and usable in written English.
It can be used when discussing a significant portion or percentage of a whole in various contexts, such as statistics, mathematics, or general descriptions.
Example: "A rather large fraction of the population supports the new policy, indicating widespread approval."
Alternatives: "a considerable portion" or "a significant percentage".
Tires, to overcome the rolling resistance, are responsible for a rather large fraction of energy consumed by vehicles, and a 10% reduction in the rolling resistance corresponds to a 2% decline in the fuel consumption, which, for instance, would save 1 2 billion gallon of fuel per year consumed by the entire passenger vehicle fleet in the United States.
In this work, droplets containing a rather large fraction of solvents were transferred to substrates, and therefore, the films required time for solvent evaporation after the deposition.
In our study, a rather large fraction of the patients (16 out of 27) did undergo a liver resection, thereby making it impossible to correlate early changes in FLT uptake to progression-free survival.
Given the size and breadth of contributing organizations (including many substance suppliers, patent databases, natural product collections, literature databases, etc)., PubChem might be considered to represent a rather large fraction of all known (small molecule, organic) chemistry.
We showed that, as a consequence, a large fraction of hybrids offspring closely resembles one of the two parents and is equally well adapted as that parent, rather than being an unfit amalgam of the properties of the two parents.
This can be summarized by two simple notions: "what goes around, comes around" and "the golden rule". A professor who "steals" royalties from a colleague by photocopying a large fraction of a book rather than assigning the students to buy it could face repercussions in professional advancement and other matters governed by peer review.
During its rather long lifetime, a large fraction of the energy output has been in the form of multi-TeV electrons.
Borders had a highly seasonal business, with a large fraction of earnings in the fourth quarter.
However, our streamlined approach using generalized questions allowed us to rapidly survey a large fraction of the hospital worker population, rather than just medical professionals.
