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1.
J Colloid Interface Sci ; 209(2): 374-379, 1999 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-9885265

RESUMO

The contribution of the pulse and alternating magnetic fields on the magnetic effects is examined and compared with that of the static field, using a rotational device by which the pulse and alternating fields are able to be applied to the stationary sample. The followings are found: (i) the substantial time required to reach the maximum magnetic effect in the pulse and alternating fields is much smaller than the time in the static field, (ii) the magnetic effect does depend on the frequency of magnetic field, and (iii) the pulse and alternating magnetic fields make the quasi-stable structure more stable than the static field. The results are discussed and compared with the magnetic effects in flow loops reported elsewhere. Copyright 1999 Academic Press.

2.
J Colloid Interface Sci ; 210(1): 1-7, 1999 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-9924102

RESUMO

Effects of magnetic exposure on an ion-exchange process are investigated, employing ion-exchange resins. The electrolyte solution, resin suspension, and water are mixed in a container, and the mass transfer coefficient is determined by measuring the change of the ionic concentration in the bulk. Two methods of magnetic exposure are performed: case (1) in which only the electrolyte solution is exposed to the magnetic field and case (2) in which only the resin suspension is exposed to the magnetic field. The following features are found in both cases: (i) the film mass transfer rate reduces by about 5% when the exposure time is greater than 25 min, (ii) the magnetic effect is reduced by adding the alcohol, (iii) the magnetic effect remains for about 3 days but disappears after 6 days, and (iv) the magnetic effect is observable in the solutions of structure-disordering ions, but not in the solutions of structure-ordering ions. As for the temperature dependence, the magnetic effect decreases with temperature in case (1) but it stays constant in case (2). It is postulated that the magnetic effects are attributable to the stabilization of water molecules around the structure-ordering ion and those on the resin surface. Copyright 1999 Academic Press.

3.
J Colloid Interface Sci ; 204(2): 363-8, 1998 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-9698416

RESUMO

The short-range interaction force between a mica surface and an AFM probe tip in electrolyte solutions was measured by atomic force microscopy (AFM) to directly evaluate the thickness of the adsorbed layer on the surface. The magnetic effects were estimated by comparing the thickness in the magnetized solution with that in nonmagnetized solution. It was found that (i) the magnetic exposure thickens the adsorbed layer on the surface in electrolyte solutions, (ii) the magnetic effects are easily destroyed by the external disturbance, (iii) there exists a memory in the magnetic effects, which remains for at least a day, (iv) the magnetic effects appear mostly in the solutions of structure-disordering cations, such as Cs+, Rb+, and K+, and (v) the results are consistent with those obtained in preceding macroscopic experiments. It is hypothesized from these results that the water molecules weekly bound around the structure-disordering ions are quasistabilized and structured by the magnetic exposure and that the magnetic thickening of the adsorbed layer is caused by the adsorption of those structured ions on the surface. Copyright 1998 Academic Press.

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