the classical greek period 600-350 bce
the Hellenistic Greek period 350 - 150 bce
the 'imperial' period 150 bce - whenever ce
Virtually all of the great scientific and technical achievements of antiquity were from the Hellenistic Greek society - the society of euclid, eratosthenes, archimedes, ctesibius, hipparchus, chrysippus, herophilus, supported by the Ptolemies in north Africa.
All this scientific work came to an abrupt end around 150bce due to the roman conquests, and the political atmosphere they created. Carthage (itself a cosmopolitan center of learning with close ties to the greek world) was not he only north african city razed to its foundations by Rome. Its easier to list the survivors: (1) Alexandria and (2) Rhodes. This completes the list. And the academics didn't survive: in 145bce Ptolemy VIII persecuted the city's greek elite so all the intellectuals fled, and the romans made a hobby of enslaving greek intellectuals, to have them work as copyists and teach their children to read.
Thus in a very short span of time, virtually all of the physical books were destroyed when the cities were destroyed, and the intellectual culture that understood the ideas was eliminated. There was a partial renaissance during the Pax Romana (ptolemy, galen, etc), but the understanding of the science was much more primitive and quickly faded with no state and cultural support.
As for technology - roman engineering was typically less advanced than greek engineering, and for technically difficult things the latin writing are both crude and wrong: their scientific engineering was done by importing engineers from the east. The antikythera mechanism (late 2nd century bce) is a good example of the decline: there is nothing of comparable mechanical complexity from the roman period, neither in archeology or in Heron.
See Russo for very readable up to date academic scholarship on this kind of thing.