No abstract

The temperature dependence of the dielectric constant and dissipation in potassium dihydrogen phosphate ͑KDP͒, its deuterated compound ͑DKDP͒, triglycine sulfate ͑TGS͒, and TGS doped with ␣-alanine ͑LATGS͒ has been studied at various frequencies. It is found that the relaxation time of domain freezing in KDP and DKDP in the kHz range can be described by the Vogel-Fulcher relation. Evidence of domain freezing in TGS is presented through an analysis of relaxation time related to domain walls and a comparison between TGS and LATGS. Studies of internal friction and compliance show preliminary evidence of domain freezing in CuAlZnNi alloy. A domain-freezing model is proposed based upon the collective pinning of randomly distributed pinning centers to domain walls. Some key experiments related to domain freezing, such as ͑1͒ the Vogel-Fulcher relation for relaxation time; ͑2͒ the size effect of domain freezing; ͑3͒ two kinds of relaxation in low-and high-frequency ranges, respectively; and ͑4͒ the dependence of T F on defect density and applied field, etc., are explained. ͓S0163-1829͑97͒01323-4͔

We study the effects of the nanopore size on the flow-induced capture of the star polymer by a nanopore and the afterward translocation, using a hybrid simulation method that couples point particles into a fluctuating lattice-Boltzmann fluid. Our simulation demonstrates that the optimal forward arm number decreases slowly with the increase of the length of the nanopore. Compared to the minor effect of the length of the nanopore, the optimal forward arm number obviously increases with the increase of the width of the nanopore, which can clarify the current controversial issue for the optimal forward arm number between the theory and experiments. In addition, our results indicate that the critical velocity flux of the star polymer is independent of the nanopore size. Our work bridges the experimental results and the theoretical understanding, which can provide comprehensive insights for the characterization and the purification of the star polymers.