6,052 research outputs found
Some aspects of global Lambda polarization in heavy-ion collisions
Large orbital angular momentum can be generated in non-central heavy-ion
collisions, and part of it is expected to be converted into final particle's
polarization due to the spin-orbit coupling. Within the framework of A
Multi-Phase Transport (AMPT) model, we studied the vorticity-induced
polarization of hyperons at the midrapidity region in
Au-Au collisions at energies GeV. Our results show
that the global polarization decreases with the collisional energies and is
consistent with the recent STAR measurements. This behavior can be understood
by less asymmetry of participant matter in the midrapidity region due to faster
expansion of fireball at higher energies. As another evidence, we discuss how
much the angular momentum is deposited in different rapidity region. The result
supports our asymmetry argument.Comment: 6 pages, 4 figures, CPOD 2017 proceedin
Geometric bionics: Lotus effect helps polystyrene nanotube films get good blood compatibility
Various biomaterials have been widely used for manufacturing biomedical applications including artificial organs, medical devices and disposable clinical apparatus, such as vascular prostheses, blood pumps, artificial kidney, artificial hearts, dialyzers and plasma separators, which could be used in contact with blood^1^. However, the research tasks of improving hemocompatibility of biomaterials have been carrying out with the development of biomedical requirements^2^. Since the interactions that lead to surface-induced thrombosis occurring at the blood-biomaterial interface become a reason of familiar current complications with grafts therapy, improvement of the blood compatibility of artificial polymer surfaces is, therefore a major issue in biomaterials science^3^. After decades of focused research, various approaches of modifying biomaterial surfaces through chemical or biochemical methods to improve their hemocompatibility were obtained^1^. In this article, we report that polystyrene nanotube films with morphology similar to the papilla on lotus leaf can be used as blood-contacted biomaterials by virtue of Lotus effect^4^. Clearly, this idea, resulting from geometric bionics that mimicking the structure design of lotus leaf, is very novel technique for preparation of hemocompatible biomaterials
Vorticity and Spin Polarization in Heavy Ion Collisions: Transport Models
Heavy ion collisions generate strong fluid vorticty in the produced hot
quark-gluon matter which could in turn induce measurable spin polarization of
hadrons. We review recent progress on the vorticity formation and spin
polarization in heavy ion collisions with transport models. We present an
introduction to the fluid vorticity in non-relativistic and relativistic
hydrodynamics and address various properties of the vorticity formed in heavy
ion collisions. We discuss the spin polarization in a vortical fluid using the
Wigner function formalism in which we derive the freeze-out formula for the
spin polarization. Finally we give a brief overview of recent theoretical
results for both the global and local spin polarization of and
hyperons.Comment: V2: 29 pages, 15 figures, published in Lecture Notes in Physics
vol.987, "Strongly Interacting Matter under Rotation", page 281-30
Chandrasekhar-Kendall-Woltjer-Taylor state in a resistive plasma
We give a criterion for the Chandrasekhar-Kendall-Woltjer-Taylor (CKWT) state
in a resistive plasma. We find that the lowest momentum (longest wavelength) of
the initial helicity amplitudes of magnetic fields are the key to the CKWT
state which can be reached if one helicity is favored over the other. This
indicates that the imbalance between two helicities at the lowest momentum or
longest wavelength in the initial conditions is essential to the CKWT state. A
few examples of initial conditions for helicity amplitudes are taken to support
the above statement both analytically and numerically.Comment: RevTex 4.1, 19 pages, 3 figure
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