The phrase "a first measurement" is correct and usable in written English.
It can be used when referring to the initial data point or observation taken in a series of measurements or experiments.
Example: "In our experiment, a first measurement was taken to establish a baseline for comparison."
Alternatives: "an initial measurement" or "the primary measurement".
We also report on a first measurement of aging with the MCP PMT.
Our group has done a first measurement of the full temperature dependence of the superheating field of niobium using SRF cavities and has shown that it depends strongly on the preparation of the niobium surface.
Elegant experiments are being carried out, or are in preparation, to improve the precision with which the solar and atmospheric neutrino-oscillation parameters are known, and to attempt to make a first measurement of the small mixing angle θ13.
"For a first measurement, which is of the same accuracy as KTeV, we will need 6 to 9 months of collecting data," he says.
Then a first measurement was taken at pH about 6. Subsequently the pH was increased again and a downward titration was carried out.
A first measurement series was performed 5/7 days after the end of irradiation with measurement times of 3000 and 9000 s for sample for determining As, Au, Br, Cd, La, Mo, Sb, Sm, W [7, 13, 40].
To ensure that true MVIC was measured, a second measurement session was conducted.
For all measurements, the mean of the two measurements was used, unless a third measurement was taken (if the two measures differed by more than the prescribed amount).
Height will be measured in duplicate with a third measurement taken if the difference is ≥ 0.5 cm.
If a third measurement was taken, the average of the two nearest measures was used.
A second measurement of the same urinary bladder section (adjacent area) was measured with a pixel size of 5 μm.
