5,037 research outputs found
Quantum Correction in Exact Quantization Rules
An exact quantization rule for the Schr\"{o}dinger equation is presented. In
the exact quantization rule, in addition to , there is an integral term,
called the quantum correction. For the exactly solvable systems we find that
the quantum correction is an invariant, independent of the number of nodes in
the wave function. In those systems, the energy levels of all the bound states
can be easily calculated from the exact quantization rule and the solution for
the ground state, which can be obtained by solving the Riccati equation. With
this new method, we re-calculate the energy levels for the one-dimensional
systems with a finite square well, with the Morse potential, with the symmetric
and asymmetric Rosen-Morse potentials, and with the first and the second
P\"{o}schl-Teller potentials, for the harmonic oscillators both in one
dimension and in three dimensions, and for the hydrogen atom.Comment: 10 pages, no figure, Revte
Isospin dependence of projectile-like fragment production at intermediate energies
The cross sections of fragments produced in 140 MeV Ca + Be
and Ni + Be reactions are calculated by the statistical
abration-ablation(SAA) model and compared to the experimental results measured
at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State
University. The fragment isotopic and isotonic cross section distributions of
Ca and Ca, Ni and Ni, Ca and Ni, and
Ca and Ni are compared and the isospin dependence of the
projectile fragmentation is studied. It is found that the isospin dependence
decreases and disappears in the central collisions. The shapes of the fragment
isotopic and isotonic cross section distributions are found to be very similar
for symmetric projectile nuclei. The shapes of the fragment isotopic and
isotonic distributions of different asymmetric projectiles produced in
peripheral reactions are found very similar. The similarity of the
distributions are related to the similar proton and neutron density
distributions inside the nucleus in framework of the SAA model.Comment: 7 pages, 4 figures; to be published in Phys Rev
Digital Quantum Simulation of Yang-Mills Theory and Hadronization
A quantum algorithm with polynomial complexity to non-perturbatively
calculate the Dyson series of SU(N) Yang-Mills theory is formulated in terms of
quantum circuits. Applying it to the quantum simulation of quantum
chromodynamics (QCD), the quark and gluon's wave functions evolved from the
initial states by the interactions can be observed and the information from
wave functions can be extracted at any discrete time. This may help us
understand the natures of the hadronization which has been an outstanding
question of significant implication on high energy phenomenological studies.Comment: 8 pages, 1 figur
Effective DBHF Method for Asymmetric Nuclear Matter and Finite Nuclei
A new decomposition of the Dirac structure of nucleon self-energies in the
Dirac Brueckner-Hartree-Fock (DBHF) approach is adopted to investigate the
equation of state for asymmetric nuclear matter. The effective coupling
constants of , , and mesons with a density
dependence in the relativistic mean field approach are deduced by reproducing
the nucleon self-energy resulting from the DBHF at each density for symmetric
and asymmetric nuclear matter. With these couplings the properties of finite
nuclei are investigated. The agreement of charge radii and binding energies of
finite nuclei with the experimental data are improved simultaneously in
comparison with the projection method. It seems that the properties of finite
nuclei are sensitive to the scheme used for the DBHF self-energy extraction. We
may conclude that the properties of the asymmetric nuclear matter and finite
nuclei could be well described by the new decomposition approach of the G
matrix.Comment: 16 pages, 5 figure
Scaling of Anisotropic Flows and Nuclear Equation of State in Intermediate Energy Heavy Ion Collisions
Elliptic flow () and hexadecupole flow () of light clusters have
been studied in details for 25 MeV/nucleon Kr + Sn at large
impact parameters by Quantum Molecular Dynamics model with different potential
parameters. Four parameter sets which include soft or hard equation of state
(EOS) with/without symmetry energy term are used. Both number-of-nucleon ()
scaling of the elliptic flow versus transverse momentum () and the scaling
of versus have been demonstrated for the light clusters
in all above calculation conditions. It was also found that the ratio of
keeps a constant of 1/2 which is independent of for all the
light fragments. By comparisons among different combinations of EOS and
symmetry potential term, the results show that the above scaling behaviors are
solid which do not depend the details of potential, while the strength of flows
is sensitive to EOS and symmetry potential term.Comment: 5 pages, 5 figure
A hybrid control method to suppress the three time fundamental frequency neutral-point voltage fluctuation in a VIENNA rectifier
This paper presents a solution to the control of the three times fundamental frequency fluctuation of the neutral-point in a VIENNA rectifier. A hybrid method combining a dynamic adjustment factor with a voltage deviation control of the split DC-link is proposed. The fluctuation of the neutral-point has been analyzed and the reason for the three times fundamental frequency fluctuation has been described using a mathematic model. As well as minimizing the three times fundamental frequency component in the neutral-point voltage the proposed control method also provides immunity to the influence of changes in the capacitor voltage. Furthermore, significant fluctuation in the neutral-point voltage caused by asymmetric capacitor parameters or unbalanced load can be effectively reduced by using a hybrid control method combining additional adjustment coefficients. The feasibility and effectiveness of the proposed strategy has been verified through the presented simulation and experimental results
Analysis of bacterial diversity in two oil blocks from two low-permeability reservoirs with high salinities
The community diversities of two oil reservoirs with low permeability of 1.81 x 10 \u273 and 2.29 x 10 \u273 1/4m 2 in Changqing, China, were investigated using a high throughput sequencing technique to analyze the influence of biostimulation with a nutrient activator on the bacterial communities. These two blocks differed significantly in salinity (average 17,500 vs 40,900 mg/L). A core simulation test was used to evaluate the effectiveness of indigenous microbial-enhanced oil recovery (MEOR). The results indicated that in the two high salinity oil reservoirs, one reservoir having relatively lower salinity level and a narrow salinity range had higher bacterial and phylogenetic diversity. The addition of the nutrient activator increased the diversity of the bacterial community structure and the diversity differences between the two blocks. The results of the core simulation test showed that the bacterial community in the reservoir with a salinity level of 17,500 mg/L did not show significant higher MEOR efficiency compared with the reservoir with 40,900 mg/L i.e. MEOR efficiency of 8.12% vs 6.56% (test p = 0.291 \u3e 0.05). Therefore, salinity levels affected the bacterial diversities in the two low permeability oil blocks remarkably. But the influence of salinity for the MEOR recovery was slightly
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