41 research outputs found
Hysteresis and Fractional Matching in Thin Nb Films with Rectangular Arrays of Nanoscaled Magnetic Dots
We have investigated the periodic pinning of magnetic flux quanta in thin Nb
films with rectangular arrays of magnetic dots. In this type of pinning
geometry, a change in the periodicity and shape of the minima in the
magnetoresistance occurs for magnetic fields exceeding a certain threshold
value. This has been explained recently in terms of a reconfiguration
transition of the vortex lattice due to an increasing vortex-vortex interaction
with increasing magnetic field. In this picture the dominating elastic energy
at high fields forces the vortex lattice to form a square symmetry rather than
being commensurate to the rectangular geometry of the pinning array. In this
paper we present a comparative study of rectangular arrays with Ni-dots,
Co-dots and holes. In the magnetic dot arrays, we found a strong fractional
matching effect up to the second order matching field. In contrast, no clear
fractional matching is seen after the reconfiguration. Additionally, we
discovered the existence of hysteresis in the magnetoresistance in the
crossover between the low and the high field regime. We found evidence that
this effect is correlated to the reconfiguration phenomenon rather than to the
magnetic state of the dots. The temperature and angular dependences of the
effect have been measured and possible models are discussed to explain this
behavior.Comment: 1 Table, 5 Figure
Pennsylvania Folklife Vol. 35, No. 1
• Grandmother\u27s Flower Garden: The Quilts of Sadie Ida Christian Laycock • Our Good Old One-Room School Days • A Parade from the Past • The Philip Arndts of Manheim (1797-1888) • Pennsylvania German Cookery • Aldes un Neieshttps://digitalcommons.ursinus.edu/pafolklifemag/1109/thumbnail.jp
Pennsylvania Folklife Vol. 35, No. 1
• Grandmother\u27s Flower Garden: The Quilts of Sadie Ida Christian Laycock • Our Good Old One-Room School Days • A Parade from the Past • The Philip Arndts of Manheim (1797-1888) • Pennsylvania German Cookery • Aldes un Neieshttps://digitalcommons.ursinus.edu/pafolklifemag/1109/thumbnail.jp
Theory of Type-II Superconductors with Finite London Penetration Depth
Previous continuum theory of type-II superconductors of various shapes with
and without vortex pinning in an applied magnetic field and with transport
current, is generalized to account for a finite London penetration depth
lambda. This extension is particularly important at low inductions B, where the
transition to the Meissner state is now described correctly, and for films with
thickness comparable to or smaller than lambda. The finite width of the surface
layer with screening currents and the correct dc and ac responses in various
geometries follow naturally from an equation of motion for the current density
in which the integral kernel now accounts for finite lambda. New geometries
considered here are thick and thin strips with applied current, and `washers',
i.e. thin film squares with a slot and central hole as used for SQUIDs.Comment: 14 pages, including 15 high-resolution figure
Neutrophils can Promote Clotting via FXI and Impact Clot Structure via Neutrophil Extracellular Traps in a Distinctive Manner in vitro
Neutrophils and neutrophil extracellular traps (NETs) have been shown to be involved in coagulation. However, the interactions between neutrophils or NETs and fibrin(ogen) in clots, and the mechanisms behind these interactions are not yet fully understood. In this in vitro study, the role of neutrophils or NETs on clot structure, formation and dissolution was studied with a combination of confocal microscopy, turbidity and permeation experiments. Factor (F)XII, FXI and FVII-deficient plasmas were used to investigate which factors may be involved in the procoagulant effects. We found both neutrophils and NETs promote clotting in plasma without the addition of other coagulation triggers, but not in purified fibrinogen, indicating that other factors mediate the interaction. The procoagulant effects of neutrophils and NETs were also observed in FXII- and FVII-deficient plasma. In FXI-deficient plasma, only the procoagulant effects of NETs were observed, but not of neutrophils. NETs increased the density of clots, particularly in the vicinity of the NETs, while neutrophils-induced clots were less stable and more porous. In conclusion, NETs accelerate clotting and contribute to the formation of a denser, more lysis resistant clot architecture. Neutrophils, or their released mediators, may induce clotting in a different manner to NETs, mediated by FXI
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Hanford Works Report HW-36734
The absorption of the important fission products by plants is quantitatively presented as a concentration factor which is defined as the ratio of the fission product concentration found in the leaves to the fission product concentration found in the nutrient substrate. Of the fission products, the isotopes of strontium were found to be the most important by virtue of their high concentration factor, long half-life, and low maximum permissible amounts for animals. Iodine and barium follow in importance, with cesium moderately important in some soils. All other fission products have concentration factors less than strontium by 100 or more. The effect on the concentration factor of different agricultural plants, as well as different organs of the same plant, causes variations of about a factor of ten or less for each isotope. The concentration factor tends to increase as the pH of the nutrient substrate is decreased. Addition of stable carrier to the substrate does not decrease the amount of the radioactive isotope that is absorbed into the plant. The presence of iodine and yttrium carrier actually causes a significant increase in the concentration of the respective radioactive isotopes in the plant tissue