The phrase "are generated only when" is correct and usable in written English.
It can be used to specify a condition under which something occurs or is produced.
Example: "Reports are generated only when the data collection is complete."
Alternatives: "are produced solely when" or "are created exclusively when".
Firstly, CDRs are sparse in time because they are generated only when a transaction occurs and not at fixed periodic intervals.
AlphaLISA signals are generated only when the acceptor-bead conjugated antibody and the donor-bead conjugated biotinylated antibody bind to the same target protein molecule, which brings the acceptor and donor beads to close proximity (<200 nm) so that the single O2 molecules could be transferred from the donor to the acceptor (Bielefeld-Sevigny, 2009).
Since chemiluminescent photons are generated only when the reactants are present, very little signal is observed for the negative control sample, thereby providing a low background.
More specifically, with chemiluminescence, photons are generated only when the reactants are present, unlike fluorescence where an excitation source could induce nonspecific radiation from either scattering or background excitation of the sample matrix.
But its scope is limited by the fact that data is generated only when a physician notices something and reports it.
Runoff from an element is generated only when its saturation threshold is exceeded.
Ripples were generated only when the average sand thickness was greater than 0.7.
Previous studies have indicated that a flow-induced voltage was generated only when the electrodes were aligned parallel to the flow (type 1), while no voltage was generated when the electrodes were aligned perpendicular to the flow (type 2) [1, 6].
The experimental results showed that effective bonding could be generated only when particle velocity exceeds 500 m/s for Al alloy substrates, and 800 m/s for stainless steel 316 L substrates.
More spheres were generated only when BIO treatment was present during secondary passaging.
Some PCR products were generated only when 100 ng DNA template were used.
