Price anomalies in the used car market.

[Dataset available: http://hdl.handle.net/10411/15566]

Nylon 46-polytetramethylene oxide segmented block copolymers

Block copolymers were synthesized from amine-terminated polytetramethylene oxide (PMTO) (Mw 800 and 1130) and polyamide 4,6 salt. First prepolymers were prepared at 200–210°C in the presence of a solvent (pyrrolidone). The prepolymers were postcondensed at 255°C (where possible in the solid state) to a high molecular weight. In the materials the endgroups were analysed, and the inherent viscosities and ethanol extraction values measured. The thermal properties were determined with d.s.c. and d.m.a. With ethanol, polyether could be extracted. Thus it seems that not all the polyether is present as part of the block copolymer. Melt phasing seems to have taken place and occurs even more with the higher molecular weight PTMO. With d.m.a. two glass transitions were observed; one of the polyether phase and one of the polyamide-rich phase. The melting temperatures of these polyamide 4,6 block copolymers are high (200–270°C), and the torsion modulus remained fairly constant up to these high melting temperatures

‘Giant’ magnetoresistance in obliquely co-evaporated Co-Ag films

Magnetoresistance (MR) measurements at room temperature have been performed on obliquely (co-) evaporated Ag-Co films deposited at room- and elevated-temperatures. The ‘giant’ magnetoresistance ratio (max. 13% for a composition of about Co35Ag65) over a wide range of compositions has been measured. The films are polycrystalline and grown in a columnar morphology. The columnar diameter depends on the thickness and is < 20 nm at 400 nm thickness. From XRD, NMR and saturation magnetization (Ms) vs. at% Ag, one can conclude that the films consist of Co-Co and Ag-Ag clusters. The coercivity depends on the thickness of the films (100–700 nm) and varies from 5 to 15 kA/m

Neutron reflectometry on Co-Cr layers

Polarized neutron reflection experiments were performed on a thin in-plane magnetized Co-Cr layer deposited on a quartz substrate. Data taken at a low magnetic field ( 0.1 T) clearly indicate the existence of an initial layer at the substrate side, whereas data at saturation ( 0.7 T) are consistent with a rather homogeneous magnetization

Correlated non-perturbative electron dynamics with quantum trajectories

An approach to electron correlation effects in atoms that uses quantum trajectories is presented. A comparison with the exact quantum mechanical results for 1D Helium atom shows that the major features of the correlated ground state distribution and of the strong field ionization dynamics are reproduced with quantum trajectories. The intra-atomic resonant transitions are described accurately by a trajectory ensemble. The present approach reduces significantly the computational time and it can be used for both bound and ionizing electrons.Comment: 9 pages, 4 figure

Giant magnetoresistance in Co/Cu multilayers sputtered with Kr

This paper presents some results of magnetoresistance measurements on Kr-sputter-deposited Co/Cu multilayers. We find that Co/Cu MLs sputtered with Kr gas show a larger GMR effect than those sputtered with Ar gas

Domain wall theory and exchange stiffness in Co/Pd multilayers

The stripe model of domain structure in multilayers is studied by micromagnetic simulation. The results indicate a strong reduction of the effective domain wall energy (by dipolar effects). Domain width measurements on sputtered Co/Pd multilayers are compared with the theory. The estimated exchange stiffness is comparable with that of bulk Co. The effects of interface roughness and of interlayer exchange are discussed