The phrase 'was firstly observed' is correct and can be used in written English.
It is used to indicate that something was noticed or identified before other things that followed. For example, "Alien life on Earth was firstly observed during the Apollo 11 mission to the moon."
A reversible couple of redox peaks at 3.0 V and 3.7 V was firstly observed.
The reduction of Eu3+→Eu2+ was firstly observed in the aluminate phosphor of Sr4Al14O25: Eu synthesized in air condition.
BD study demonstrated that outgrowth of thin regenerating axons into the frontal area of the tongue was firstly observed at 14 post-operative days, and presynaptic formation of neuromuscular junction (NMJ) was observed from 21 post-operative days.
Although Ti 46Al 8Nb is nominally slightly pro-peritectic composition, an axial elongated channel-like area with peritectically transformed microstructure was firstly observed in solidified ingots by SEM-BSE and EDX analyses, where Al content locally exceeds 47 at.%.
During the process of subsequent low temperature heat treatment of precursor gel, the formation of α-Al2O3 was firstly observed at temperature as low as 400 °C without the appearance of other transition phases.
Four ternary compounds (τ1, τ2, τ3, τ4) were identified in these isothermal sections, and one new phase named τ9 (Ni9Hf19Si22) was firstly observed both at 1000 °C and 1100 °C.
Interestingly, the chair-form water hexamer is firstly observed being interpenetrated by the inorganic cluster.
A well-defined cyclic voltammogram of hemoglobin at MG modified electrode has been firstly observed.
A more significant cervical elongation among sauropodomorphs is firstly observed in the minimal clade including Plateosaurus (neck length/trunk length c. 0.75) and sauropods, which typically exhibit necks longer than the trunk43.
Significantly, well separated oxidation peaks of Tyr and CysH were firstly observed at physiological pH at the OMC electrode.
In all cases where supersonic combustions were achieved, ignitions were firstly observed in the boundary layer at the expanding cross section zone.
