усовершенствование

см. тж. вносить усовершенствование; улучшение

Teams are working on the advancement of the technology of gas-cooled reactors.

Refinements (or Improvements) in observational procedure (or in apparatus) ...

Efforts are directed towards refining (or perfecting) present techniques.

Источник: Русско-английский научно-технический словарь на Gufo.me