Coherence of Disordered Bosonic Gas with Two-and Three-Body Interactions

We theoretically and numerically investigate the coherence of disordered bosonic gas with effective two- and three-body interactions within a two-site Bose-Hubbard model. By properly adjusting the two- and three-body interactions and the disorder, the coherence of the system exhibits new and interesting phenomena, including the resonance character of coherence against the disorder in the purely two- or three-body interactions system. More interestingly, the disorder and three-body interactions together can suppress the coherence of the purely three-body interactions system, which is different from the case in which the disorder and two-body interactions together can enhance the coherence in certain values of two.body interaction. Furthermore, when two- or three- body interactions are attractive or repulsive, the phase coherence exhibits completely different phenomena. In particular, if two- or three-body interactions are attractive, the coherence of the system can be significantly enhanced in certain regions. Correspondingly, the phase coherence of the system is strongly related to the effective interaction energy. The results provide a possible way for studying the coherence of bosonic gas with multi-atoms＇ interactions in the presence of the disorder.

Numerical simulations and comparative analysis of two- and three-dimensional circulating fluidized bed reactors for CO2 capture

Carbon dioxide(CO2),the main gas emitted from fossil burning,is the primary contributor to global warming.Circulating fluidized bed reactor(CFBR)is proved as an energy-efficient method for post-combustion CO2 capture.The numerical simulation by computational fluid dynamics(CFD)is believed as a promising tool to study CO2 adsorption process in CFBR.Although three-dimensional(3D)simulations were proved to have better predicting performance with the experimental results,two-dimensional(2D)simulations have been widely reported for qualitative and quantitative studies on gas-solid behavior in CFBR for its higher computational efficiency recently.However,the discrepancies between 2D and 3D simulations have rarely been evaluated by detailed study.Considering that the differences between the 2D and 3D simulations will vary substantially with the changes of independent operating conditions,it is beneficial to lower computational costs to clarify the effects of dimensionality on the numerical CO2 adsorption runs under various operating conditions.In this work,the comparative analysis for CO2 adsorption in 2D and 3D simulations was conducted to enlighten the effects of dimensionality on the hydrodynamics and reaction behaviors,in which the separation rate,species distribution and hydrodynamic characteristics were comparatively studied for both model frames.With both accuracy and computational costs considered,the viable suggestions were provided in selecting appropriate model frame for the studies on optimization of operating conditions,which directly affect the capture and energy efficiencies of cyclic CO2 capture process in CFBR.

Emission of high-energy alpha particles in nuclear reactions of ^(48)Ca and ^(56)Fe ions on ^(181)Ta and ^(238)U targets

The results of experiments on measuring the energy spectra of alpha particles in reactions with heavy ions are presented.The measurements were performed using the high-resolution magnetic analyzer MAVR with beams of ^(48)Ca(280 MeV)and ^(56)Fe(320 and 400 MeV)on ^(181)Ta and ^(238)U targets at an angle of 0°.A strong dependence of the double differential cross sections for production of alpha particles on the atomic number of the target nucleus was observed,which indicates that fast alpha particles are mainly emitted from the target nucleus;this conclusion was also confirmed by calculations within the time-dependent Schrödinger equation approach.An analysis of the obtained experimental data was carried out within the model of moving sources modified to consider the kinematic limits for two-body and three-body exit channels.