4,542 research outputs found
Parametric uncertainty analysis of pulse wave propagation in a model of a human arterial network
Accepted versio
Finite-volume effects on octet-baryon masses in covariant baryon chiral perturbation theory
We study finite-volume effects on the masses of the ground-state octet
baryons using covariant baryon chiral perturbation theory (ChPT) up to
next-to-leading order by analyzing the latest lattice Quantum
ChromoDynamics (LQCD) results from the NPLQCD collaboration. Contributions of
virtual decuplet baryons are taken into account using the "consistent" coupling
scheme. We compare our results with those obtained from heavy baryon ChPT and
show that, although both approaches can describe well the lattice data, the
underlying physics is different: In HBChPT, virtual decuplet baryons play a
more important role than they do in covariant ChPT. This is because the virtual
octet baryon contributions to finite-volume corrections are larger in covariant
ChPT than in HBChPT, while the contributions of intermediate decuplet baryons
are smaller, because of relativistic effects. We observe that for the octet
baryon masses, at fixed () finite-volume corrections decrease
as approaches its physical value, provided that the strange quark mass
is at or close to its physical value, as in most LQCD setups.Comment: 15 pages, 5 figure
Theory of Interfacial Plasmon-Phonon Scattering in Supported Graphene
One of the factors limiting electron mobility in supported graphene is remote
phonon scattering. We formulate the theory of the coupling between graphene
plasmon and substrate surface polar phonon (SPP) modes, and find that it leads
to the formation of interfacial plasmon-phonon (IPP) modes, from which the
phenomena of dynamic anti-screening and screening of remote phonons emerge. The
remote phonon-limited mobilities for SiO, HfO, h-BN and
AlO substrates are computed using our theory. We find that h-BN
yields the highest peak mobility, but in the practically useful high-density
range the mobility in HfO-supported graphene is high, despite the fact
that HfO is a high- dielectric with low-frequency modes. Our
theory predicts that the strong temperature dependence of the total mobility
effectively vanishes at very high carrier concentrations. The effects of
polycrystallinity on IPP scattering are also discussed.Comment: 33 pages, 7 figure
Grain boundary ferromagnetism in vanadium-doped InO thin films
Room temperature ferromagnetism was observed in InO\,^{\circ}{\rm C}_2_3$ host lattice, thus excluding the existence of secondary phases
of vanadium compounds. Magnetic measurements based on SQUID magnetometry and
magnetic circular dichroism confirm that the magnetism is at grain boundaries
and also in the grains. The overall magnetization originates from the competing
effects between grains and grain boundaries.Comment: 12 pages, 7 figures, 1 table, accepted by Europhysics Letter
Neutrino oscillations in de Sitter space-time
We try to understand flavor oscillations and to develop the formulae for
describing neutrino oscillations in de Sitter space-time. First, the covariant
Dirac equation is investigated under the conformally flat coordinates of de
Sitter geometry. Then, we obtain the exact solutions of the Dirac equation and
indicate the explicit form of the phase of wave function. Next, the concise
formulae for calculating the neutrino oscillation probabilities in de Sitter
space-time are given. Finally, The difference between our formulae and the
standard result in Minkowski space-time is pointed out.Comment: 13 pages, no figure
Optimization of a fed-batch bioreactor for 1,3-propanediol production using hybrid nonlinear optimal control
A nonlinear hybrid system was proposed to describe the fed-batch bioconversion of glycerol to 1,3-propanediol with substrate open loop inputs and pH logic control in previous work [47]. The current work concerns the optimal control of this fed-batch process. We slightly modify the hybrid system to provide a more convenient mathematical description for the optimal control of the fed-batch culture. Taking the feeding instants and the terminal time as decision variables, we formulate an optimal control model with the productivity of 1,3-propanediol as the performance index. Inequality path constraints involved in the optimal control problem are transformed into a group of end-point constraints by introducing an auxiliary hybrid system. The original optimal control problem is associated with a family of approximation problems. The gradients of the cost functional and the end-point constraint functions are derived from the parametric sensitivity system. On this basis, we construct a gradient-based algorithm to solve the approximation problems. Numerical results show that the productivity of 1,3-propanediol can be increased considerably by employing our optimal control policy
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