排序方式: 共有37条查询结果,搜索用时 31 毫秒
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Goodchild I Collier L Millar SL Prokes I Lord JC Butts CP Bowers J Webster JR Heenan RK 《Journal of colloid and interface science》2007,307(2):455-468
The surface, phase and aggregation behaviour of mixtures of 1-alkyl-3-methylimidazolium halide, [C(n)mim]X, where n is the alkyl chain length, with water has been explored using a variety of methods. Critical micelle concentrations (cmc) and micelle structures have been determined for aqueous [C(n)mim]Br solutions for n=2, 4, 6, 8, and 10. Small-angle neutron scattering (SANS) measurements reveal that for the n=8 and 10 systems, at concentrations just above the cmc, small near-spherical aggregates exist, which, after initial growth, possess core radii (aggregation numbers) at intermediate concentrations of 10.5+/-0.5 Angstrom (22+/-2) and 13.2+/-0.5 Angstrom (40+/-3), respectively, for n=8 and n=10. Towards higher concentrations, the aggregates appear to grow, with the aggregates in the [C(10)mim]Br system becoming increasingly elongated (prolate) with increasing concentration. No evident aggregates are formed in the systems with n=2 and 4. In the n=6 system, it appears that oblate aggregates with radius approximately 9 Angstrom form at the cmc and that the radius increases with increasing concentration. For longer alkyl chain lengths, at high concentrations lyotropic mesophases form in some systems. The mesophase region for the [C(8)mim]Cl system has been explored across the composition range using X-ray diffraction and (2)H NMR spectroscopy. Both techniques suggest that a major hexagonal phase with lattice parameter of 29.5+/-0.5 Angstrom coexists with a minor lamellar phase (23.5+/-0.3 Angstrom) or possibly a second hexagonal phase (27.1+/-0.4 Angstrom). The area per adsorbed molecule at the surface of [C(8)mim]Br solutions has been measured as a function of concentration using neutron reflectometry. A minimum in the area per molecule behaviour is coincident with a minimum identified in the surface tension isotherm occurring close to the cmc. The data suggest depletion of [C(8)mim]Br from the surface region occurs at concentrations immediately above the cmc. 相似文献
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Llobet A Christianson AD Bao W Gardner JS Swainson IP Lynn JW Mignot JM Prokes K Pagliuso PG Moreno NO Sarrao JL Thompson JD Lacerda AH 《Physical review letters》2005,95(21):217002
The heavy fermion system exhibits properties that range from an incommensurate antiferromagnet for small to an exotic superconductor on the Ir-rich end of the phase diagram. At intermediate where antiferromagnetism coexists with superconductivity, two types of magnetic order are observed: the incommensurate one of and a new, commensurate antiferromagnetism that orders separately. The coexistence of -electron superconductivity with two distinct -electron magnetic orders is unique among unconventional superconductors, adding a new variety to the usual coexistence found in magnetic superconductors. 相似文献
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Jack Emerson-King Dr. Ivan Prokes Dr. Adrian B. Chaplin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(25):6317-6319
The synthesis and characterisation of a homologous series of rhodium 2,2′-biphenyl complexes featuring intramolecular dative bonding of the nominally inert and weakly coordinating trifluoromethyl group are described. Presence of these interactions is evidenced in the solid state using X-ray diffraction, with Rh−F contacts of 2.36–2.45 Å, and in solution using NMR spectroscopy, through hindered C−CF3 bond rotation and the presence of time-averaged 1JRhF and 2JPF coupling. 相似文献
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Ch. Binek T. Kato W. Kleemann O. Petracic D. Bertrand F. Bourdarot P. Burlet H. Aruga Katori K. Katsumata K. Prokes S. Welzel 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,15(1):35-40
In order to clarify the nature of the additional phase transition at H
1
(
T
) <
H
c
(
T
) of the layered antiferromagnetic (AF) insulator FeBr
2
as found by Aruga Katori et al. (1996) we measured the intensity of different Bragg-peaks in different scattering geometries. Transverse AF ordering is observed
in both AF phases, AF I and AF II. Its order parameter exhibits a peak at T
1
=
T
(
H
1
) in temperature scans and does not vanish in zero field. Possible origins of the step-like increase of the transverse ferromagnetic
ordering induced by a weak in-plane field component when entering AF I below T1 are discussed.
Received 27 September 1999 and Received in final form 6 December 1999 相似文献
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K. Prokes R.T. Gramsma Y. Janssen E. Brück K.H.J. Buschow F.R. de Boer 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,16(3):429-434
Neutron-diffraction experiments reveal that ErFe6Ga6 forms in the tetragonal ThMn12-type of structure (space group I4/mmm). The Fe sublattice orders ferromagnetically below K. The Er moments order antiparallel to the Fe moments which, below about 250 K, leads to a decrease of the total magnetization.
The easy magnetization direction of ErFe6Ga6 is perpendicular to the c-axis in the whole temperature range. Refinement at 2 K shows that ErFe6Ga6 orders ferrimagnetically with Er moments of 8.5 (2) and Fe moments at the 8(j) site of 1.9 (1) and at the 8(f) site of 1.7 (1) , respectively. At room temperature, ErFe6Ga6 exhibits the same type of magnetic order, however with substantially lower Er moments of 1.0 (4) and Fe moments at the 8(f) site of 1.2 (2) . The Fe moments at the 8(j) site amount to 1.9 (5) /Fe.
Received 24 November 1999 and Received in final form 27 March 2000 相似文献
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V.K. Birulev V. Genchev N.N. Govorun T.S. Grigalashvili B.N. Guskov J. Hladky I.M. Ivanchenko V.D. Kekelidze D. Kiss V.G. Krivokhizhin V.V. Kukhtin M.F. Likhachev E. Nagy M. Novak A. Prokes Yu.I. Salomatin I.A. Savin L.V. Silvestrov J. Votruba 《Nuclear Physics B》1976,115(2):249-268
The energy dependence of the modulus and phase of the KL0-KS0 regeneration amplitude on hydrogen in the range of 14–50 GeV has been investigated at the Serpukhov 70 GeV accelerator.It has been established that the modulus of the modified regeneration amplitude decreases with increasing momentum as . The amplitude phase is energy-independent and its mean value is ?210 = ?132° ± 5°. The results obtained are compared with other experiments and with predictions of different theoretical models. 相似文献
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