The phrase 'has been frequently employed' is correct and usable in written English.
You can use it when you want to express that something has been frequently used, relied on, or resorted to in the past. For example: "The technique of using fish as fertilizer has been frequently employed in this region."
Using a method that has been frequently employed to measure discrimination in hiring, I also gave the bots characteristically white or characteristically black first and last names.
In the past studies, MHz-order ultrasound has been frequently employed in the ultrasound separation techniques and the flocculation mechanism of particles due to the acoustic radiation force has been reported.
This concept has been frequently employed to prove existence theorems on common fixed points.
Foucault (1978) developed the concept of governmentality, which has been frequently employed in policy analyses.
It is worth mentioning that the one-sided Lipschitz condition has been frequently employed in the study of synchronization of complex networks [25, 26].
In particular, silver film has been frequently employed because of its intrinsic properties such as low contact resistance and low refractive index.
Albedo dosemeters, usually based on thermo-luminescence detectors, have been frequently employed in personal neutron dosimetry.
Noticeably, a large number of oxazole compounds as clinical drugs or candidates have been frequently employed for the treatment of various types of diseases, which have shown their large development value and wide potential as medicinal agents.
PEG based thermosetting phase change materials (PCMs) have been frequently employed for thermal energy storage in building and other fields due to the low cost, no toxic, no corrosive, good thermal properties and no leakage in phase change process.
Hydrogels, which are highly hydrophilic three-dimensional network of polymers, have always been regarded as one of the most promising biomaterials composite for biomedical applications, and redox-responsive hydrogels have been frequently employed in areas such as tissue engineering and drug delivery.
Equations (1.1 - 1.3 1.1 - 1.3n frequently employed in real-world applications.
