The phrase "are not only efficient" is correct and usable in written English.
It is typically used in a comparative context to highlight that something has multiple positive attributes, with efficiency being one of them.
Example: "These new processes are not only efficient but also cost-effective and environmentally friendly."
Alternatives: "are not just efficient" or "are more than just efficient".
We show that integration-deficient lentiviral particles are not only efficient in transducing DC but also that a single immunization with these vectors coding for the secreted form of the WNV envelope can prime humoral Ag-specific responses and confers complete protection against lethal challenge.
Thus insertions of iTol2 with the resulting truncations of genomic DNA from either end are not only efficient, but also highly specific to that end.
Bdelloids, although aquatic animals, are not only efficient in tolerating desiccation, but seem somehow dependent on anhydrobiosis, a circumstance that might represent a key event in their life cycle.
The need of the hour for the technology sector is to work upon such tools that are not only efficient but also economically viable so that developing nations can benefit as, ironically, it is here that the need for such measures is most.
"What she did — through long discussions and lots of arguments into the night — was to make me think why capitalism is not only efficient and practical, but also moral," he told a reporter from the Times in 1974.
Despite the many years he spent at her side, despite his previous admission that it was Rand who persuaded him that "capitalism is not only efficient and practical but also moral", he mentioned her in his memoirs only to suggest that it was a youthful indiscretion – and this, it seems, is now the official version.
AC is not only efficient in removal of heavy metals, but also for other contaminants present in water/wastewater.
The method is not only efficient, but also provides tangible accuracy increases in tests on practical machining problems.
Numerical results are presented to demonstrate that the method is not only efficient but also very effective in solving metamaterial Maxwellʼs equations.
They illustrate that LOD-MS is not only efficient and simple in coding, but also has almost all the nature of multisymplectic integrators.
The multi-domain design approach is not only efficient for mixed-domain problems, but is also useful for addressing separate single-domain design problems with a single tool.
