991 research outputs found
Parton Branching in Color Mutation Model
The soft production problem in hadronic collisions as described in the
eikonal color mutation branching model is improved in the way that the initial
parton distribution is treated. Furry branching of the partons is considered as
a means of describing the nonperturbative process of parton reproduction in
soft interaction. The values of all the moments, and , for q=2,...,5,
as well as their energy dependences can be correctly determined by the use of
only two parameters.Comment: 8 pages (LaTeX) + 2 figures (ps files), submitted to Phys. Rev.
Enhancement of vortex pinning in superconductor/ferromagnet bilayers via angled demagnetization
We use local and global magnetometry measurements to study the influence of
magnetic domain width w on the domain-induced vortex pinning in
superconducting/ferromagnetic bilayers, built of a Nb film and a ferromagnetic
Co/Pt multilayer with perpendicular magnetic anisotropy, with an insulating
layer to eliminate proximity effect. The quasi-periodic domain patterns with
different and systematically adjustable width w, as acquired by a special
demagnetization procedure, exert tunable vortex pinning on a superconducting
layer. The largest enhancement of vortex pinning, by a factor of more than 10,
occurs when w ~ 310 nm is close to the magnetic penetration depth.Comment: 5 pages, 3 figures, accepted to Phys. Rev. B, Rapid Communication
A Color Mutation Model of Soft Interaction in High Energy Hadronic Collisions
A comprehensive model, called ECOMB, is proposed to describe multiparticle
production by soft interaction. It incorporates the eikonal formalism, parton
model, color mutation, branching and recombination. The physics is conceptually
opposite to the dynamics that underlies the fragmentation of a string. The
partons are present initially in a hadronic collision; they form a single,
large, color-neutral cluster until color mutation of the quarks leads to a
fission of the cluster into two color-neutral subclusters. The mutation and
branching processes continue until only pairs are left in each small
cluster. The model contains self-similar dynamics and exhibits scaling behavior
in the factorial moments. It can satisfactorily reproduce the intermittency
data that no other model has been able to fit.Comment: 24 pages including 11 figures in revtex epsf styl
Dual Stimuli-Responsive Polysaccharide Hydrogels Manufactured by Radiation Technique
Featured Application Stimuli-responsive hydrogels encompassing biobased polymers are anticipated for utilization in various fields, starting from drug delivery systems through temporal actuators and water reservoirs to biodegradable microelements and nutrient delivery depots. This paper describes the results of the radiation-induced crosslinking of polysaccharides modified with hydroxypropyl and carboxymethyl functional groups, hydroxypropylcellulose (HPC) and carboxymethylcellulose (CMC), respectively, without and with poly(ethylene glycol) diacrylate (PEGDA) as a crosslinking agent, to obtain dual stimuli-responsive hydrogels. The gels were characterized in terms of water uptake and gel fraction, parameters that mainly depend on the HPC-CMC compositions, but also on the macromer crosslinker content and the absorbed dose. The swelling of hydrogels is controlled by both the temperature, due to the amphiphilic character of HPC and pH, due to the anionic functional groups of CMC. In spite of a similar degree of substitution in both cellulose derivatives, 1.4 for HPC and 1.2 for CMC, the pH response of hydrogels with an equal content of both polysaccharides is considerably higher-a reduction in swelling of up to 95% with a decrease in the pH to 2 was recorded-than the response to thermal-stimulus-wherein a reduction in swelling of less than 70% with an increasing in temperature to 55 degrees C was found. These biopolymers-based hydrogels of specific, stimuli-responsive swelling properties are anticipated in applications where a combination of two stimuli is essential and biodegradation may be required
Tuning Vortex Confinement by Magnetic Domains in a Superconductor/Ferromagnet Bilayer
We use a line of miniature Hall sensors to study the effect of magnetic-domain-induced vortex confinement on the flux dynamics in a superconductor/ferromagnet bilayer. A single tunable bilayer is built of a ferromagnetic Co/Pt multilayer with perpendicular magnetic anisotropy and a superconducting Nb layer, with the insulating layer in-between to avoid the proximity effect. The magnetic-domain patterns of various geometries are reversibly predefined in the Co/Pt multilayer using the appropriate magnetization procedure. The magnetic-domain geometry strongly affects vortex dynamics, leading to geometry-dependent trapping of vortices at the sample edge, nonuniform flux penetration, and strongly nonuniform critical current density. With the decreasing temperature, the magnetic pinning increases, but this increase is substantially weaker than that of the intrinsic pinning. The analysis of the initial flux penetration suggests that vortices may form various vortex structures, including disordered Abrikosov lattice or single and double vortex chains, in which minimal vortex-vortex distance is comparable to the magnetic penetration depth
Tuning Vortex Confinement by Magnetic Domains in a Superconductor/Ferromagnet Bilayer
We use a line of miniature Hall sensors to study the effect of magnetic-domain-induced vortex confinement on the flux dynamics in a superconductor/ferromagnet bilayer. A single tunable bilayer is built of a ferromagnetic Co/Pt multilayer with perpendicular magnetic anisotropy and a superconducting Nb layer, with the insulating layer in-between to avoid the proximity effect. The magnetic-domain patterns of various geometries are reversibly predefined in the Co/Pt multilayer using the appropriate magnetization procedure. The magnetic-domain geometry strongly affects vortex dynamics, leading to geometry-dependent trapping of vortices at the sample edge, nonuniform flux penetration, and strongly nonuniform critical current density. With the decreasing temperature, the magnetic pinning increases, but this increase is substantially weaker than that of the intrinsic pinning. The analysis of the initial flux penetration suggests that vortices may form various vortex structures, including disordered Abrikosov lattice or single and double vortex chains, in which minimal vortex-vortex distance is comparable to the magnetic penetration depth
Transesterification of PHA to Oligomers Covalently Bonded with (Bio)Active Compounds Containing Either Carboxyl or Hydroxyl Functionalities
© 2015 The Authors. Published by Public Library of Science. This is an open access article available under a Creative Commons licence.
The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1371/journal.pone.0120149This manuscript presents the synthesis and structural characterisation of novel biodegradable polymeric controlled-release systems of pesticides with potentially higher resistance to weather conditions in comparison to conventional forms of pesticides. Two methods for the preparation of pesticide-oligomer conjugates using the transesterification reaction were developed. The first method of obtaining conjugates, which consist of bioactive compounds with the carboxyl group and polyhydroxyalkanoates (PHAs) oligomers, is "one-pot" transesterification. In the second method, conjugates of bioactive compounds with hydroxyl group and polyhydroxyalkanoates oligomers were obtained in two-step method, through cyclic poly(3-hydroxybutyrate) oligomers. The obtained pesticide-PHA conjugates were comprehensively characterised using GPC, 1H NMR and mass spectrometry techniques. The structural characterisation of the obtained products at the molecular level with the aid of mass spectrometry confirmed that both of the synthetic strategies employed led to the formation of conjugates in which selected pesticides were covalently bonded to PHA oligomers via a hydrolysable ester bond
Density saturation and the decrease of the normalised width of the multiplicity distribution in high energy pp collisions
It is experimentally observed that the width of the KNO multiplicity
distribution --or the negative binomial parameter 1/k-- for pp collisions, in
the energy region 10 to 1800 GeV, is an increasing function of the energy. We
argue that in models with parton or string saturation such trend will necessary
change: at some energy the distribution will start to become narrower. In the
framework of percolating strings, we have estimated the change to occur at an
energy of the order of 5--10 TeV.Comment: 10 pages, 4 figures, uses elsart and amsmath; comparison with some
other models was added; version accepted by PL
Generalized Relativistic Meson Wave Function
We study the most general, relativistic, constituent meson
wave function within a new covariant framework. We find that by including a
tensor wave function component, a pure valence quark model is now capable of
reproducing not only all static pion data (, )
but also the distribution amplitude, form factor , and structure
functions. Further, our generalized spin wave function provides a much better
detailed description of meson properties than models using a simple
relativistic extension of the nonrelativistic wave function.Comment: 17 pages, REXTeX 3.0 file, (uuencoded postscript files of 8 figures
appended
Scenarios for multiplicity distributions in pp collisions in the TeV energy region
Possible scenarios based on available experimental data and phenomenological
knowledge of the GeV energy region are extended to the TeV energy region in the
framework of the weighted superposition mechanism of soft and semi-hard events.
KNO scaling violations, forward-backward multiplicity correlations, Hq vs. q
oscillations and shoulder structures are discussed.Comment: 10 pages, 10 figures, talk given at "Focus on Multiplicity" (Bari,
Italy, June 2004
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