2,665 research outputs found
CETP-catalysed transfer of cholesterylesters from HDL to apo B-containing lipoproteins in plasma from diabetic patients
Dzyaloshinsky-Moriya interaction in vesignieite: A route to freezing in a quantum kagome antiferromagnet
We report an electron spin resonance investigation of the geometrically
frustrated spin-1/2 kagome antiferromagnet vesignieite,
BaCuVO(OH). Analysis of the line widths and line shifts
indicates the dominance of in-plane Dzyaloshinsky-Moriya anisotropy that is
proposed to suppress strongly quantum spin fluctuations and thus to promote
long-range ordering rather than a spin-liquid state. We also evidence an
enhanced spin-phonon contribution that might originate from a lattice
instability and discuss the origin of a low-temperature mismatch between
intrinsic and bulk susceptibility in terms of local inhomogeneity
Symmetric and antisymmetric exchange anisotropies in quasi-one-dimensional CuSeO as revealed by ESR
We present an electron spin resonance (ESR) study of single-crystalline spin
chain-system CuSeO in the frequency range between 9 GHz and 450 GHz. In
a wide temperature range above the N\'{e}el temperature K we observe
strong and anisotropic frequency dependence of a resonance linewidth. Although
sizeable interchain interaction ( is the intrachain
interaction) is present in this system, the ESR results agree well with the
Oshikawa-Affleck theory for one-dimensional Heisenberg antiferromagnet.
This theory is used to extract the anisotropies present in CuSeO. We
find that the symmetric anisotropic exchange and the
antisymmetric Dzyaloshinskii-Moriya (DM) interaction are
very similar in size in this system. Staggered-field susceptibility induced by
the presence of the DM interaction is witnessed in the macroscopic
susceptibility anisotropy.Comment: 8 pages, 7 figures, 2 tables, published in Phys. Rev.
Large Horizontal Displacements of Houses in Rotterdam
In 1983 it was established that six blocks of terrace houses in Rotterdam had undergone large horizontal displacements. These displacements were caused by insufficient stability of the adjacent quay and as a result one of the blocks had moved as much as 2.5 m since 1958. The foundation piles of the houses were not designed to resist any horizontal loading. As a result of these large horizontal movements the piles had deflected to such an extent that complete failure was feared. This paper describes the remedial measures that were taken to improve the stability of the quay and foundations of the houses. The present displacement behaviour is compared with the horizontal displacement predicted from creep analysis
Selective degradation of the high density lipoprotein-2 subfraction by heparin-releasable liver lipase
Quenching Spin Decoherence in Diamond through Spin Bath Polarization
We experimentally demonstrate that the decoherence of a spin by a spin bath
can be completely eliminated by fully polarizing the spin bath. We use electron
paramagnetic resonance at 240 gigahertz and 8 Tesla to study the spin coherence
time of nitrogen-vacancy centers and nitrogen impurities in diamond from
room temperature down to 1.3 K. A sharp increase of is observed below the
Zeeman energy (11.5 K). The data are well described by a suppression of the
flip-flop induced spin bath fluctuations due to thermal spin polarization.
saturates at below 2 K, where the spin bath polarization
is 99.4 %.Comment: 5 pages and 3 figure
Optimum vegetation characteristics, assimilation, and transpiration during a dry season. 2. Model evaluation
High-frequency electron paramagnetic resonance investigation of the Fe3+ impurity center in polycrystalline PbTiO3 in its ferroelectric phase
The intrinsic iron(III) impurity center in polycrystalline lead titanate was
investigated by means of high-frequency electron paramagnetic resonance (EPR)
spectroscopy in order to determine the local-environment sensitive fine
structure parameter D. At a spectrometer frequency of 190 GHz, spectral
analysis of a powder sample was unambiguously possible. The observed mean value
D = +35.28 GHz can be rationalized if Fe3+ ions substitute for Ti4+ at the
B-site of the perovskite ABO3 lattice forming a directly coordinated iron -
oxygen vacancy defect associate. A consistent fit of the multi-frequency data
necessitated use of a distribution of D values with a variance of about 1 GHz.
This statistical distribution of values is probably related to more distant
defects and vacancies.Comment: 6 pages, 3 figures, 1 table, to appear in J. App. Phys, 96 (2004
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