You remember the Algorans had just figured a way to put a double barrier on the channels.

By this time, all three of them were settled in their shelter under the rock, the entrance sealed with a double barrier of thorny bushes.

They drove out of the airport, passing through a double barrier and a gate.

The combination of p16 and p27 in naked mole rats cells is a double barrier to cell proliferation.

This cell had a double barrier; steel within, bulletproof glass without.

On the fifth night after leaving the Bogdanovists, they approached the equator, and the double barrier of the fallen elevator cable.

A double barrier of steel fencing was erected around the convention hall.

The peninsula was guarded on the mainland side by double barrier reinforced with towers.

But communications had a double barrier on Serieve.

One wall of his room is a double barrier which opens on the hall.