3,563 research outputs found
On QCD and Effective Locality
In a recent paper it was shown how quark scattering in a quenched, eikonal
model led to a momentum-transfer dependent amplitude expressed in terms of
Halpern's functional integral; and how the requirement of manifest gauge
invariance converted that functional integral into a local integral, capable of
being evaluated with precision by a finite set of numerical integrations. We
here prove that this property of "effective locality" holds true for all quark
processes, without approximation and without exception.Comment: Expanded and Revised in REVTeX 4.1, 14 pages, follow-on work of Eur.
Phys. J. C65, pp.395-411 (2010) or arXiv:0903.2644v2 [hep-th
A new gas discharge process for preparation of non-fouling surfaces on biomaterials
A non-fouling surface containing immobilized polyethylene oxide (PEO) was achieved using an argon radio-frequency glow discharge treatment (RFGD) of polyethylene films precoated with Brij hydrocarbon-PEO surfactants. Surface wettability of RFGD-treated and washed surfaces increased the most when PEO surfactants with unsaturated and/or long alkyl tails were used. ESCA measurements of treated and washed surfaces showed increases of surface O/C ratios and ether carbon peaks in high resolution Cls spectra. These results demonstrate the retention of the PEO surfactants on the treated surfaces. Fibrinogen adsorp tion on these treated surfaces was significantly reduced, from 500 to 50 ng/cm2, indicating the non-fouling properties of the RFGD-immobilized PEO surfactants
The quantization of the symplectic groupoid of the standard Podles sphere
We give an explicit form of the symplectic groupoid that integrates the
semiclassical standard Podles sphere. We show that Sheu's groupoid, whose
convolution C*-algebra quantizes the sphere, appears as the groupoid of the
Bohr-Sommerfeld leaves of a (singular) real polarization of the symplectic
groupoid. By using a complex polarization we recover the convolution algebra on
the space of polarized sections. We stress the role of the modular class in the
definition of the scalar product in order to get the correct quantum space.Comment: 33 pages; minor correction
Modeling of convection phenomena in Bridgman-Stockbarger crystal growth
Thermal convection phenomena in a vertically oriented Bridgman-Stockbarger apparatus were modeled by computer simulations for different gravity conditions, ranging from earth conditions to extremely low gravity, approximate space conditions. The modeling results were obtained by the application of a state-of-the art, transient, multi-dimensional, completely densimetrically coupled, discrete-element computational model which was specifically developed for the simulation of flow, temperature, and species concentration conditions in two-phase (solid-liquid) systems. The computational model was applied to the simulation of the flow and the thermal conditions associated with the convection phenomena in a modified Germanium-Silicon charge enclosed in a stationary fused-silica ampoule. The results clearly indicated that the gravitational field strength influences the characteristics of the coherent vortical flow patterns, interface shape and position, maximum melt velocity, and interfacial normal temperature gradient
Immobilization of Polyethylene Oxide Surfactants for Non-Fouling Biomaterial Surfaces Using an Argon Glow Discharge Treatment
A non-fouling (protein-resistant) polymer surface is achieved by the covalent immobilization of polyethylene oxide (PEO) surfactants using an inert gas discharge treatment. Treated surfaces have been characterized using electron spectroscopy for chemical analysis (ESCA), static secondary ion mass spectrometry (SSIMS), water contact angle measurement, fibrinogen adsorption, and platelet adhesion. This paper is intended to review our recent work in using this simple surface modification process to obtain wettable polymer surfaces in general, and non-fouling biomaterial surfaces in particular
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