6,566 research outputs found
Electronic Raman scattering of Tl-2223 and the symmetry of the supercon- ducting gap
Single crystalline Tl2Ba2Ca2Cu3O10 was studied using electronic Raman
scattering. The renormalization of the scattering continuum was investigated as
a function of the scattering geometry to determine the superconducting energy
gap 2Delta(k). The A1g- and B2g-symmetry component show a linear frequency
behaviour of the scattering intensity with a peak related to the energy gap,
while the B1g-symmetry component shows a characteristic behaviour at higher
frequencies. The observed frequency dependencies are consistent with a
dx^2-y^2-wave symmetry of the gap and yield a ratio of 2Delta/k_BT_c=7.4. With
the polarization of the scattered and incident light either parallel or
perpendicular to the CuO2-planes a strong anisotropy due to the layered
structure was detected, which indicates an almost 2 dimensional behaviour of
this system.Comment: 2 pages, Postscript-file including 2 figures. Accepted for
publication in the Proceedings of the M^2SHTSC IV Conference, Grenoble
(France), 5-9 July 1994. Proceedings to be published in Physica C. Contact
address: [email protected]
Technological quality of organic wheat in Europe
The demand for high quality organic bread wheat is increasing. The quality level of organic wheat harvested in EU is mainly dependant on variety, environmental conditions and agronomic practices. In some countries, protein content and composition, influencing technological value, are equivalent to those produced under conventional practices. Beside agronomical techniques, technological processes can help to maintain a good quality. Pre-treatments before milling such as debranning were found to be efficient in reducing DON contamination. The project highlighted the necessity to redefine the methods to assess the quality of organic wheat
Evidence of breakdown of the spin symmetry in diluted 2D electron gases
Recent claims of an experimental demonstration of spontaneous spin
polarisation in dilute electron gases \cite{young99} revived long standing
theoretical discussions \cite{ceper99,bloch}. In two dimensions, the
stabilisation of a ferromagnetic fluid might be hindered by the occurrence of
the metal-insulator transition at low densities \cite{abra79}. To circumvent
localisation in the two-dimensional electron gas (2DEG) we investigated the low
populated second electron subband, where the disorder potential is mainly
screened by the high density of the first subband. This letter reports on the
breakdown of the spin symmetry in a 2DEG, revealed by the abrupt enhancement of
the exchange and correlation terms of the Coulomb interaction, as determined
from the energies of the collective charge and spin excitations. Inelastic
light scattering experiments and calculations within the time-dependent local
spin-density approximation give strong evidence for the existence of a
ferromagnetic ground state in the diluted regime.Comment: 4 pages, 4 figures, Revte
Willmore minimizers with prescribed isoperimetric ratio
Motivated by a simple model for elastic cell membranes, we minimize the
Willmore functional among two-dimensional spheres embedded in R^3 with
prescribed isoperimetric ratio
Techniques to improve technological and sanitary quality
Agronomical ways for better quality and safety
Choice of cultivar is an efficient way to obtain higher grain quality. Intercropping legumes (grain or forage) improves weed competition and N availability for wheat crop or succeeding crop. Green manure can be an effective alternative to farmyard manure. Fertilization with readily available nitrogen improves yield and quality when water is available. Reduced tillage affects soil fertility and wheat yield but has little effects on grain quality.
Technological ways for better quality and safety
Milling process strongly influences flour characteristics. Stone milling improves nutritive value; characteristics remain very stable independent of the milling yield. Flour characteristics from roller milling appear very susceptible to the milling yield. Increasing the milling yield in the aim of enriching nutritional quality has a detrimental effect either on safety (DON) or on bread-making quality (bread volume)
Investigation of bandwidth loading in optical fibre transmission using amplified spontaneous emission noise
The use of spectrally shaped amplified spontaneous emission noise (SS-ASE) as a method for emulating interfering channels in optical fibre transmission systems has been studied. It is shown that the use of SS-ASE leads to a slightly pessimistic performance relative to the use of conventionally modulated interfering channels in the nonlinear regime. The additional nonlinear interference noise (on the channel under test), due to the Gaussian nature of SS-ASE, has been calculated using a combination of the Gaussian noise (GN) and enhanced GN (EGN) models for the entire C-band (4.5 THz) and experimentally shown to provide a lower bound for transmission performance
The Effect of Cortex/Medulla Proportions on Molecular Diagnoses in Kidney Transplant Biopsies: Rejection and Injury Can Be Assessed in Medulla
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137720/1/ajt14233_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137720/2/ajt14233.pd
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