Study of the ionic Peierls-Hubbard model using density matrix renormalization group methods

Density matrix renormalization group methods are used to investigate the quantum phase diagram of a one-dimensional half-filled ionic Hubbard model with bond-charge attraction, which can be mapped from the Su-Schrieffer-Heeger-type electron-phonon coupling at the antiadiabatic limit. A bond order wave (dimerized) phase which separates the band insulator from the Mott insulator always exists as long as electron-phonon coupling is present. This is qualitatively different from that at the adiabatic limit. Our results indicate that electron-electron interaction, ionic potential and quantum phonon fluctuations combine in the formation of the bond-order wave phase

Numerical Study on Shear Flow in Sliding Bearing with Partial Slip Surface

AbstractFor revealing the effects of slip on such characteristics as friction force and load-bearing capacity of sliding bearing, shear flows of a Newtonian fluid with a varying partial slip surface were computed using finite volume method. Calculation results showed that slip would decrease the friction force, which however was not affected by the location of slip region. The load-bearing capacity of sliding bearing closely depended on the location of slip region, especially the locations of the starting and end points of slip region. A well-designed partial slip surface can improve the load-bearing capacity, otherwise slip would cause lubrication failure

Teaching evaluation: a complicated issue

To justify/quantify/qualify on teaching evaluation may be difficult and not objective as there are so much variables. Comparing teaching evaluations obtained by individual lecturer may not be meaningful, as each staff facing independent course with different students, course and other variables (or statistically, each is an independent event and a single mean value must not be compared directly with another)

Hawking Radiation of an Arbitrarily Accelerating Kinnersley Black Hole: Spin-Acceleration Coupling Effect

The Hawking radiation of Weyl neutrinos in an arbitrarily accelerating Kinnersley black hole is investigated by using a method of the generalized tortoise coordinate transformation. Both the location and temperature of the event horizon depend on the time and on the angles. They coincide with previous results, but the thermal radiation spectrum of massless spinor particles displays a kind of spin-acceleration coupling effect.Comment: 8 pages, no figure, revtex 4.0, revisted version with typesetting errors and misprint correcte

Numerical simulation study on the impact area of six-hole oxygen lance in a 260 t converter

In the process of converter smelting, the impact area formed when the jet sprayed by the oxygen lance hits the molten pool to a large extent determines the steel quality. In this study, six sets of oxygen lance models with different inclination angles were established based on the a 260 t converter, and the influence of the jet angle and position of the oxygen lance nozzle on the jet impact area was studied by numerical simulation, and the law of the change of the impact area with the lance position under different impact velocity was explained through theoretical analysis. It was found that the effective impact area of the jet with an inclination angle of 15° was the largest, and the stirring of the molten pool was more uniform