2672546 exch exchange 1 2672547 exch exchange event within the U 1 2672548 exch exchange repulsion E 1 2672551 exch exchange time tau 1 2672552 exch exchange, k 1 2672549 exch exist in the calculated U 1 2672550 exch experiments to probe residual hydrophobic clustering in the U 1 2672553 exch ion-exchange constants of the plasticizer-free microsphere were log K 1