2,244 research outputs found
An on-line harmonics elimination PWM scheme for three-phase voltage source inverters
An on-line harmonic elimination PWM (HEPWM) scheme for three-phase voltage source inverters is proposed. It is based on curve fitting method derived from the trajectories of the exact (off-line) HEPWM angles. The
main advantage of the technique is its fast and efficient
realization using a microprocessor. An outline to obtain the switching angles is presented. The method is proven by
experimental result
The spread of the gluon k_t-distribution and the determination of the saturation scale at hadron colliders in resummed NLL BFKL
The transverse momentum distribution of soft hadrons and jets that accompany
central hard-scattering production at hadron colliders is of great importance,
since it has a direct bearing on the ability to separate new physics signals
from Standard Model backgrounds. We compare the predictions for the gluonic
k_t-distribution using two different approaches: resummed NLL BFKL and DGLAP
evolution. We find that as long as the initial and final virtualities (k_t)
along the emission chain are not too close to each other, the NLL resummed BFKL
results do not differ significantly from those obtained using standard DGLAP
evolution. The saturation momentum Q_s(x), calculated within the resummed BFKL
approach, grows with 1/x even slower than in the leading-order DGLAP case.Comment: 24 pages, 8 figures, An improved, slightly more precise NLL
resummation is used and the figures are updated accordingly. The conclusions
are unchange
Field Redefinition Invariance in Quantum Field Theory
The issue of field redefinition invariance of path integrals in quantum field
theory is reexamined. A ``paradox'' is presented involving the reduction to an
effective quantum-mechanical theory of a -dimensional free scalar field
in a Minkowskian spacetime with compactified spatial coordinates. The
implementation of field redefinitions both before and after the reduction
suggests that operator-ordering issues in quantum field theory should not be
ignored.Comment: 7 page
Vector boson mass generation without new fields
Previously a model of only vector fields with a local U(2) symmetry was
introduced for which one finds a massless U(1) photon and a massive SU(2)
vector boson in the lattice regularization. Here it is shown that quantization
of its classical continuum action leads to perturbative renormalization
difficulties. But, non-perturbative Monte Carlo calculations favor the
existence of a quantum continuum limit.Comment: 4 pages, 3 figures, 2 tables. Revised after referee reports. One
error eliminate
Physiological Responses of Blood and Immune Organs of Broiler Chicken Fed Dietary Black Cumin Powder (Nigella Sativa) During Dry Seasons
This study was designed to determine the physiological response of blood and immune organs ofbroiler chickens fed on various concentration of dietary black cumin powder (BCP) during the dryseason. A total number of 100 unsexed one-day old Cobb broiler chicks were used and distributed to 5treatments (control, antibiotics and without BCP, 20 g/kg BCP, 40 g/kg BCP and 60 g/kg BCP) and 4replications (5 birds for each). Physiological responses of blood and immune organs were measured at30 day of age. Addition of BCP to broiler ration did not significantly effects on physical properties ofblood (leukocytes count, erythrocytes count, haemoglobin, hematocrit, monocytes, and eosinophils) andrelative weights of thymus and bursa of fabricius, but significantly (P<0.05) increased relative weightsof spleen when compared to control. It was concluded that the black cumin grinds (Nigella sativa) as afeed additive could not change the physical properties of blood, relative weights of thymus and bursa offabricius, but it increased the relative weight of spleen at the level of 60 g/kg BCP, which could reduceadverse effects of infectious diseases in broiler chicken
Phase Transition in Asymmetrical Superfluids I: Equal Fermi Surfaces
In this paper, we study phase transitions in asymmetrical fermion
superfluids. In this scenario, the candidates to form pair are particles with
mismatched masses and chemical potentials. We derive an expression for the
critical temperature in terms of the gap and masses (or chemical potentials)
when the constraint of equal Fermi surfaces is imposed.Comment: RevTex, 11 pages, 2 figures, typos corrected and an appendix added,
accepted for publication in Phys. Rev.
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