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Xiao K.,Hunan Institute of Technology | He X.-K.,Hunan First Normal University | Zhu J.-Y.,Beijing Normal University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

Phenomenological effect of the super-inflation in loop quantum cosmology (LQC) is discussed. We investigate the case that the Universe is filled with the interacting field between massive scalar field and radiation. Considering the damping coefficient Γ as a constant, the changes of the scale factor during super-inflation with four different initial conditions are discussed, and we find that the changes of the scale factor depends on the initial values of energy density of the scalar field and radiation at the bounce point. But no matter which initial condition is chosen, the radiation always dominated at the late time. Moreover, we investigate whether the super-inflation can provide enough e-folding number. For the super-inflation starts from the quantum bounce point, the initial value of Hubble parameter H(ti)~0, then it is possible to solve the flatness problem and horizon problem. As an example, following the method of [18] to calculate particle horizon on the condition that the radiation dominated at bounce point, and we find that the Universe has had enough time to be homogeneous and isotopic. © 2013 Elsevier B.V.

Guo Y.,Hunan Institute of Technology
International Journal of Innovative Computing, Information and Control | Year: 2016

This paper deals with a stochastic two-species competitive model of plankton alleopathy. Some very verifiable criteria on the uniformly weakly persistent in the mean almost surely (a.s.) and extinction for each species are obtained. Moreover, we also prove that there is a stationary distribution to this system and it has the ergodic property. Finally, some sufficient conditions for global asymptotic stability of the positive solution are established. An example is given to illustrate our main theoretical findings. Our results are new and complement previously known results. © 2016, ICICI International .

Zhang Q.,Guizhou University of Finance and Economics | Yang L.,Hunan City University | Liao D.,Hunan Institute of Technology
Information Sciences | Year: 2014

This paper deals with the existence, the boundedness and the asymptotic behavior of the positive solutions to a first order fuzzy Ricatti difference equation xn+1=A+xnB+xn,n=0,1,...where { xn} is a sequence of positive fuzzy numbers, A,B and the initial value x0 are positive fuzzy numbers. Moreover an example is given to demonstrate the effectiveness of the results obtained.

Li L.,Hunan Institute of Technology
Journal of Alloys and Compounds | Year: 2013

Microstructure and texture evolution during super plastic deformation of Mg-Gd-Y-Zr extruded rods were investigated in the study. For the purposes, the tensile tests under super plastic deformation condition were conducted at different strain levels. The static annealing tests were performed to reveal the micro structural evolution only influenced by thermal load. Grain structure analysis proves that initial grain refinement during the preheating stage is driven by store energy inherited from extrusion deformation. Microstructure and texture analysis suggests that deformation mechanisms are initial grain boundary sliding and subsequent slip creep. Moreover, the β phases (Mg5 (Gd, Y)) on (sub) grain boundaries hinder grain boundary sliding and continuous dynamic recrystallization. Macro-texture evolution shows that texture components varied according to the transition of deformation mechanisms. Micro-texture measurement using EBSD proves that β phase has undergone severe deformation before elongation-to-failure. © 2012 Elsevier B.V. All rights reserved.

Hu L.H.,Anhui University of Science and Technology | Tang W.,Anhui University of Science and Technology | Chen L.F.,Anhui University of Science and Technology | Yi L.,Hunan Institute of Technology
Applied Thermal Engineering | Year: 2013

This paper presents an experimental investigation and non-dimensional global correlation of maximum gas temperature beneath ceiling with blockage (vehicle) at different distance from fire source in a longitudinal ventilated tunnel. Experiments are conducted in a 1/5 model tunnel (72 m long) with a simulated vehicular blockage (1.3 m × 0.4 m × 0.5 m) whose (upstream or downstream) distance from the fire ranged in 1-6 m. It is found that the blockage placed downstream has no effect on the maximum gas temperature. However, as the upstream blockage-fire distance increases, the maximum temperature decreases and then approaches an asymptotic value (similar to that with no blockage). Li model [Y.Z. Li, B. Lei, H. Ingason, The maximum temperature of buoyancy-driven smoke flow beneath the ceiling in tunnel fires, Fire Saf. J. 46 (2011) 204-210] better predicts the measured values than Kurioka model [H. Kurioka, Y. Oka, H. Satoh, O. Sugawa, Fire properties in near field of square fire source with longitudinal ventilation in tunnels, Fire Saf. J. 38(4) (2003) 319-340.] with no blockage. However, they both cannot well predict, even after amended by the (cross-section) blockage ratio proposed by Lee, the measurements with upstream blockage at different distances. Then, a non-dimensional correlation between a modification coefficient α and normalized blockage-fire distance (L) by the hydraulic diameter (D) of the tunnel is further proposed to account for different upstream blockage distances. A global model is finally developed with both blockage ratio and blockage-fire distance included, as shown to well collapse and predict the measured values. © 2013 Elsevier B.V. All rights reserved.

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