The phrase "attach firmly" is correct and usable in written English.
It can be used when giving instructions or describing the action of securing something in place.
Example: "Please ensure that you attach firmly the brackets to the wall to support the shelf."
Alternatives: "secure tightly" or "fasten securely".
Overall, the oligomers attach firmly to the surface.
(3) Mesenchymal amniocytes attach firmly to polyglycolic acid polymer.
These cells proliferate as rapidly as fetal mesenchymal amniocytes in vitro and attach firmly to polyglycolic acid scaffolds.
A major disadvantage of most polymers used in tissue engineering is their hydrophobicity; hydrophobic surfaces do not allow cells to attach firmly and, therefore, do not allow normal proliferation rates.
The microbe carries specialized proteins that help it attach firmly to the surface of cells and other proteins that blunt a host's immune-system response and prevent white blood cells from ingesting and degrading it.
As can be seen in Figure 5 both strains attach firmly to both sugarcane bagasse (left) and HT fibers (right).
These fibres reach the adjacent parts of the vertebral bodies and are attached firmly to them.
It is proved that the paints attached firmly even in severe environment with high temperature and high velocity gas flushed and recorded the temperature profile successfully.
The constant strain-rate tests were conducted with transparent end pieces attached firmly to the upper and lower ends of the specimens.
The cells attached firmly to the bottom as well as the top surface of the film and were well spread out.
The end mass is attached firmly to the beam structural layer so that the mass centre of gravity does not coincide with the point of attachment.
