| 1. |
- Delin, A, et al.
(författare)
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Optical evidence of 4f-band formation in CeN
- 1997
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Ingår i: PHYSICAL REVIEW B-CONDENSED MATTER. - : AMER INST PHYSICS. - 0163-1829. ; 55:16, s. 10173-10176
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We report ab initio calculations of the ground state and optical properties of CeN, which show that the 4f electrons in CeN are itinerant and that the intra-atomic 4f-Coulomb interaction is largely screened. A coherent 4f band of width similar to 2 eV is
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| 2. |
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| 3. |
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| 4. |
- Waltermo, Å, et al.
(författare)
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Alkyl glucosides on hydrophobic surfaces studied by surface force and wetting measurements
- 1996
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Ingår i: Journal of Colloid and Interface Science. - 0021-9797 .- 1095-7103. ; 183, s. 506-514
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Tidskriftsartikel (refereegranskat)abstract
- The wetting properties of hydrophobized surfaces in the presence of alkyl glucosides have been studied using a Wilhelmy balance technique, and the interparticle forces acting between such surfaces have been investigated using the interferometric surface force apparatus. The adsorption at concentrations well below the cmc is rather limited both for the anomerically pure octyl b-glucoside and for the technical product based on the branched octyl glucoside, 2-ethylhexyl glucoside. However, the adsorption results in a decreasing surface hydrophobicity, and consequently the force needed to separate two such surfaces from each other is reduced. At the cmc for octyl b-glucoside, a surfactant monolayer is adsorbed on each surface. The interaction between the glucose units gives rise to a short-range repulsive force. Beyond the range of this repulsive force a weak attraction is experienced. Addition of a small amount of octyl a-glucoside does not change the short-range interaction significantly. The technical 2-ethylhexyl glucoside surfactant behaves similarly to the anomerically pure surfactant at low concentrations. The solution with the technical glucoside phase-separates at high surfactant concentration. It is observed that under such conditions a thick layer is deposited on each surface.
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| 5. |
- Waltermo, Å, et al.
(författare)
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Foam and thin-liquid-film studies of alkyl glucoside systems
- 1996
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Ingår i: Langmuir. - 0743-7463 .- 1520-5827. ; 12, s. 5271-5278
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Tidskriftsartikel (refereegranskat)abstract
- The foaming behaviour of nonionic alkyl glucosides, in terms of foamability and foam stability, has been investigated using various methods. Three different foam tests, two dynamic methods: the Bikerman cylinder and the Watkins funnel, and one static method, have been employed for measuring the foamability and foam stability of nonionic surfactant solutions made from either the linear octyl b-glucoside, the linear octyl a-glucoside, or the branched octyl a-glucoside, 2-ethylhexyl a-glucoside. At low surfactant concentration there is only a small difference between the surfactants, which remains when the salt concentration increases. At high surfactant concentration octyl b-glucoside is observed to be the major foaming agent. The stability of the individual foam lamellae have also been studied with the Thin-Film-Balance technique (TFB). The stabilizing forces in these nonionic foam films is, in most cases, electrostatic double-layer forces. The thickness dependence of the repulsive forces is consistent with Poisson Boltzmann theory. As the salt concentration is increased the range of the double-layer force measured with the TFB technique decreases. This correlates with a reduction in foam stability as noticed by measuring the decay of foams formed by a shaking method. Furthermore, for the octyl b-glucoside close to cmc, only a very weak double-layer force is observed, and in this case Newton black films stabilized by steric/hydration forces are formed as noticed by TFB measurements.
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