The phrase "has mostly concentrated on" is grammatically correct and can be used in written English.
It is typically used when discussing a specific area or topic that someone has focused on primarily. Example: "Throughout his career, the author has mostly concentrated on writing historical non-fiction books."
This work has mostly concentrated on the architecture of connections between brain areas.
Despite recent increases in social spending, especially on education, the government has mostly concentrated on building up industry and infrastructure, subsidizing a host of manufacturing costs.
Previous work in the literature has mostly concentrated on the minimal wavelength assignment or the minimal add/drop wavelength assignment problem at the optical layer.
While China has engaged in extensive cooperation with Pakistan in nuclear power, its industry has mostly concentrated on an enormous building program at home.
While prior work in this field has mostly concentrated on information residing in the kernel space (process lists, network connections, and so on) and in particular on the Microsoft Windows operating system, this work focuses on Linux user space processes as they might also contain valuable information for an investigation.
The focus of the existing literature has mostly concentrated on optimizing the choices of cluster heads to meet some constraints.
Other teams have also analyzed such markers, called haplogroups, but they have mostly concentrated on the five most common ones, which have failed to resolve the issue.
Historical and philosophical analyses of control experiments have mostly concentrated on randomized controlled trials as "gold standard" for experiment-based inferences in medicine and specifically on the concept of randomization (e.g. Cartwright, Keating & Cambrosio).
Observers of the Belle saga have mostly concentrated on two aspects: they've castigated her for ostensibly glorifying vice or the exploitation of women; or they've mined her tale for morals about the perils of online anonymity.
Fish have taken these tiny Chimarra sedges consistently, but have mostly concentrated on their emerging pupae in the surface meniscus, with almost imperceptible sips and dimples in the quiet shallows.
