分类: 物理学 >> 凝聚态:结构、力学和热性能 提交时间: 2016-06-14
摘要: Heat conduction through one-dimensional (1D) coupled rotator lattices is investigated in the presence of mass gradient. It is found that thermal current in the direction of mass increasing is not asymmetric with heat flux though mass decreasing system, which is called thermal rectification. Moreover, we find that the larger is the mass gradient, the more evident is the thermal rectification effect, which is consistent with FPU lattice with mass gradient. Based on the influences of the thermal rectification on shape parameters K and A of nearest-neighbor interactions, the average temperature of atomic chain and the system size, a optimum thermal rectifier is designed, which thermal rectification efficiency has reached 70. These investigations would contribute to controlling and manipulating thermal current.
分类: 物理学 >> 核物理学 提交时间: 2023-05-19
摘要: We provide an investigation of the spectroscopic factors of resonance states in $A =5-8$ nuclei using two distinct nuclear models, the Gamow shell model (GSM) and the no-core shell model (NCSM).Configuration mixing is treated exactly in both GSM and NCSM. GSM employs the complex-energy Berggren ensemble, which treats bound, unbound resonance, and non-resonant continuum single-particle states on an equal footing.As a result, continuum coupling is taken into account in GSM, whereas it is absent in NCSM, where the harmonic oscillator basis is used.We first calculate low-lying states of helium isotopes and isotones. The results indicate that GSM can more accurately reproduce the low-lying resonance states than NCSM.The spectroscopic factors of the resonance states are also computed.Results from the GSM and NCSM are compared and show that continuum coupling plays an important role in the calculations of spectroscopic factors of resonance states.Overlap functions related to the resonance states are also systematically calculated by the GSM and NCSM. It is then demonstratedthat wave function asymptotes can only be reproduced in GSM, where continuum coupling is taken into account.
提交时间: 2017-05-02
摘要: The electroplating pretreatment of NdFeB magnets was simulated in this study, and the effect of the pickling process on element, matrix morphology and texture was discussed. The results showed that in the ordinary circumstance the acid solution concentrat
分类: 物理学 >> 核物理学 提交时间: 2023-06-20
摘要: The stellar (n, ) cross section data for the mass numbers around A 160 are of key importance to nucleosynthesis in the main component of the slow neutron capture process, which occurs in the thermally pulsing asymptotic giant branch (TPAGB). The new measurement of (n, ) cross sections for 159Tb was performed using the C6D6 detector system at the back streaming white neutron beam line (Back-n) of the China spallation neutron source (CSNS) with neutron energies ranging from 1 eV to 1 MeV. Experimental resonance capture kernels are reported up to 1.2 keV neutron energy with this capture measurement. Maxwellian-averaged cross sections (MACS) are derived from the measured 159Tb (n, ) cross sections at kT = 5100 keV and are in good agreement with the recommended data of KADoNiS-v0.3 and JEFF-3.3, while KADoNiS-v1.0 and ENDF-VIII.0 signifificantly overestimate the present MACS up to 40% and 20%, respectively. A sensitive test of the s-process nucleosynthesis is also performed with the stellar evolution code MESA. Signifificant changes in abundances around A 160 are observed between the ENDF/B-VIII.0 and present measured rate of 159Tb(n, ) 160Tb in the MESA simulation.