"closely focused on" is correct and usable in written English.
It is typically used to describe someone or something that is highly attentive or concentrating on a specific task or topic. Example sentence: "The team was closely focused on improving their sales strategy for the upcoming quarter."
The article is closely focused on bond strength experiments using high strength concrete up to class C50/60 or higher.
It is also closely focused on the rig itself.
"The major national banks are closely focused on their own problems and situations," he said.
He then spent five years at the Royal Academy Schools, where teaching was closely focused on technique.
And he insisted that Microsoft was closely focused on adapting to that change — and learning from the legacy of companies that failed to do so.
Remuneration in the finance sector needs to be more closely focused on long-term value than on short-term financial performance.
Because of the terrain, you need to keep your eyes closely focussed on the ground.
Todd Harris, one of McCain's strategists in 2000, told me that he has never worked on a campaign more closely focussed on a candidate's biography, and on that candidate's ability to project integrity.
Logitech just took to the wires to announce an "organizational alignment" that will closely focus on new "strategic priorities".
Part of future work is to study possible CHP control schemes more closely, focusing on stable CHP operation, optimal sustainability, and optimal profitability in relation to varying external grid prices.
Another example is the importance of attentiveness, especially for the smaller farms mentioned, which refers to the impact of closely focusing on sensory impressions such as unusual odors, noises, etc.
