8,520 research outputs found
Novel Non-equilibrium Phase Transition Caused by Non-linear Hadronic-quark Phase Structure
We consider how the occurrence of first-order phase transitions in
non-constant pressure differs from those at constant pressure. The former has
shown the non-linear phase structure of mixed matter, which implies a particle
number dependence of the binding energies of the two species. If the mixed
matter is mixed hadron-quark phase, nucleon outgoing from hadronic phase and
ingoing to quark phase probably reduces the system to a non-equilibrium state,
in other words, there exists the imbalance of the two phases when deconfinement
takes place. This novel non-equilibrium process is very analogous to the
nuclear reactions that nuclei emit neutrons and absorb them under appropriate
conditions. We present self-consistent thermodynamics in description for the
processes and identify the microphysics responsible for the processes. The
microphysics is an inevitable consequence of non-linear phase structure instead
of the effect of an additional dissipation force. When applying our findings to
the neutron star containing mixed hadron-quark matter, it is found that the
newly discovered energy release might strongly change the thermal evolution
behavior of the star.Comment: 18pages,3figures;to be accepted for publication in Physics Letters
QRD-Assisted Adaptive Modulation-Aided MIMO Systems
Abstract—In this paper, we propose QR-decomposition (QRD)-based adaptive modulation (AM)-aided multiple-input–multiple-output (MIMO) systems. The proposed algorithm yields a tight lower bound of the free distance (FD), which determines the error probability of the detector in thehigh-signal-to-noise-ratio (SNR) region. Thus, this QRD-based AM algorithm is capable of achieving near-optimal performance at low complexity because the full QRD, which imposes high complexity, is performed only once for each channel realization, regardless of the number of AM modes.Our simulation results show that the proposed algorithm exhibits a better bit-error-rate (BER) performance and reduced complexity compared with the existing algorithms
Anatomy of decays and effects of next-to-leading order contributions in the perturbative QCD factorization approach
In this paper, we will make systematic calculations for the branching ratios
and the CP-violating asymmetries of the twenty one decays
by employing the perturbative QCD (PQCD) factorization approach. Besides the
full leading-order (LO) contributions, all currently known next-to-leading
order (NLO) contributions are taken into account. We found numerically that:
(a) the NLO contributions can provide enhancement to the LO PQCD
predictions for and , or a reduction to
\calb(\bar{B}_s^0 \to \pi^{-} K^{*+}), and we confirmed that the inclusion of
the known NLO contributions can improve significantly the agreement between the
theory and those currently available experimental measurements, (b) the total
effects on the PQCD predictions for the relevant transition form
factors after the inclusion of the NLO twist-2 and twist-3 contributions is
generally small in magnitude: less than enhancement respect to the
leading order result, (c) for the "tree" dominated decay and the "color-suppressed-tree" decay ,
the big difference between the PQCD predictions for their branching ratios are
induced by different topological structure and by interference effects among
the decay amplitude and : constructive for the
first decay but destructive for the second one, and (d) for \bar{B}_s^0 \to
V(\eta, \etar) decays, the complex pattern of the PQCD predictions for their
branching ratios can be understood by rather different topological structures
and the interference effects between the decay amplitude \cala(V\eta_q) and
\cala(V\eta_s) due to the \eta-\etar mixing.Comment: 18 pages, 2 figures, 3 tables. Some modifications of the text.
Several new references are adde
Numerical simulation and experimental research of flow-induced noise for centrifugal pumps
The experimental system of exterior performances for centrifugal pumps is built in this paper to verify the reliability of the numerical simulation. Then, the pressure fluctuation inside centrifugal pumps is computed numerically. The computational results indicate that higher peaks of pressure fluctuation are mainly at the rotation frequency, blade frequency and double blade frequency. Comparing the computational results between the coupled and uncoupled boundary element methods, the influence of the coupling on the distribution of sound pressure level cannot be ignored. Finally, the coupling acoustic boundary element method is adopted to compute the sound field of centrifugal pumps, and its result is also verified by experiment. The pressure fluctuation of the volute plays a greater influence on the sound pressure at the outlet of centrifugal pumps. The sound pressure has shown peaks in both the blade frequency and double blade frequency. It thus indicates that interferences between the impeller and tongue are the main reasons for the flow-induced noise of centrifugal pumps
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