"is rather poor" is perfectly grammatical and perfectly usable in written English.
For example: "The quality of the food served at this restaurant is rather poor."
However, it is rather poor for the turbulent boundary layer.
This is useful for graphical material, though the image quality is rather poor.
The family is rather poor, especially since Stephen is out of work at the beginning.
However, the progress on phenoxazinone synthase and its mechanistic pathway is rather poor and has lot of scope for improvement.
Certain field investigations have shown that the correlation between the extent of annoyance due to road traffic noise and the noise dose expressed in Leq is rather poor.
In contrast, there are only few publications on the higher order modes and the current knowledge about their propagation characteristics is rather poor.
Mechanical property of semicrystalline polymer with large-size spherulites is rather poor, and needs to be improved by adding nucleating agent to make spherulites smaller.
In CEC, sensitivity for UV detection is rather poor due to the short optical path length for on-column detection in capillary separation techniques.
Experiments in a pilot plant coker have suggested that the initial particle/liquid mixing, in the spray jet, is rather poor.
However, the principal understanding of the relevant damage mechanisms and of the influence of the microstructure on the fatigue lives in this regime is rather poor.
In contrast, the positive predictive value of isolated prodromal symptoms is rather poor (much less than the 80% required for clinical validation).
