We implement a binary collision approximation to study solitary wave propagation in a two-dimensional double Y- shaped granular chain. The solitary wave was transmitted and reflected when it met the interface of the b...We implement a binary collision approximation to study solitary wave propagation in a two-dimensional double Y- shaped granular chain. The solitary wave was transmitted and reflected when it met the interface of the bifurcated branches of the Y-shaped granular chains. We obtain the analytic results of the ratios of the transmitted and reflected speeds to the incident speed of the solitary wave, the maximum force between the two neighbor beads in a solitary wave, and the total time taken by the pulse to pass through each branch. All of the analytic results are in good agreement with the experimental observations from Daraio et al. [Phys. Rev. E 82 036603 （2010）]. Moreover, we also discuss the delay effects on the arrival of split pulses, and predict the recombination of the split waves traveling in branches in the final stem of asymmetric systems. The prediction of pulse recombination is verified by our numerical results.展开更多
The first-principles calculation is performed to investigate the energy band structures,density of states(DOS)and optical properties of SrBi_(2)A_(2)O_(9)(A=Nb,Ta),by using density functional theory(DFT)with the gener...The first-principles calculation is performed to investigate the energy band structures,density of states(DOS)and optical properties of SrBi_(2)A_(2)O_(9)(A=Nb,Ta),by using density functional theory(DFT)with the generalized gradient approximation(GGA).The results show that the band−gap of SrBi_(2)A_(2)O_(9) is smaller than that of SrBi_(2)A_(2)O_(9),and that there are strong hybridizations of A−O bands,which play very important roles in the electronic properties and optical responses of SrBi_(2)A_(2)O_(9).SrBi_(2)A_(2)O_(9) stimulates much higher photocatalytic activity than SrBi_(2)A_(2)O_(9),which is due to its suitable crystal structure.展开更多
A first principles study using the full potential linearized augmented plane wave(FP-LAPW)method is applied to study the structural,electronic and optical properties of BiAlxGa1−xO3.The results show that the alloys be...A first principles study using the full potential linearized augmented plane wave(FP-LAPW)method is applied to study the structural,electronic and optical properties of BiAlxGa1−xO3.The results show that the alloys become markedly hard as the Al concentration increases.The calculated structural parameters are in good agreement with the experimental data.The band structure and density of states are obtained,which indicate that BiAlxGa1−xO3 has an indirect band gap.Moreover,the optical properties are calculated and analyzed in detail.It is proposed that BiAl_(x)Ga_(1−x)O_(3) is a promising dielectric material.展开更多
The pseudo-potential plane wave(PP-PW)method with the generalized gradient approximation(GGA)is used to calculate the structural,electronic and optical properties of cubic and tetragonal BaZr_(x)Ti_(1−x)O_(3)(BZT)(x=0...The pseudo-potential plane wave(PP-PW)method with the generalized gradient approximation(GGA)is used to calculate the structural,electronic and optical properties of cubic and tetragonal BaZr_(x)Ti_(1−x)O_(3)(BZT)(x=0,0.25,0.5,0.75).The calculated structural parameters are found to be in good agreement with the experimental data.The energy band structure density of states(DOS)are obtained,which indicates that the Zr substitute can induce the band gap widening of BaTiO3.Furthermore,their optical properties are also calculated and analyzed in detail.It is shown that the dielectric imaginary part of BZT decreases as x(Zr concentration)increases.展开更多
基金Project supported by the Science Fund for Creative Research Groups of the National Natural Science Foundation of China (Grant No. 50921002)the Fundamental Research Funds for the Central Universities of China (Grant No. 2010LKWL09)
文摘We implement a binary collision approximation to study solitary wave propagation in a two-dimensional double Y- shaped granular chain. The solitary wave was transmitted and reflected when it met the interface of the bifurcated branches of the Y-shaped granular chains. We obtain the analytic results of the ratios of the transmitted and reflected speeds to the incident speed of the solitary wave, the maximum force between the two neighbor beads in a solitary wave, and the total time taken by the pulse to pass through each branch. All of the analytic results are in good agreement with the experimental observations from Daraio et al. [Phys. Rev. E 82 036603 （2010）]. Moreover, we also discuss the delay effects on the arrival of split pulses, and predict the recombination of the split waves traveling in branches in the final stem of asymmetric systems. The prediction of pulse recombination is verified by our numerical results.
基金the Fundamental Research Funds for the Central Universities(No 2010LKWL06).
文摘The first-principles calculation is performed to investigate the energy band structures,density of states(DOS)and optical properties of SrBi_(2)A_(2)O_(9)(A=Nb,Ta),by using density functional theory(DFT)with the generalized gradient approximation(GGA).The results show that the band−gap of SrBi_(2)A_(2)O_(9) is smaller than that of SrBi_(2)A_(2)O_(9),and that there are strong hybridizations of A−O bands,which play very important roles in the electronic properties and optical responses of SrBi_(2)A_(2)O_(9).SrBi_(2)A_(2)O_(9) stimulates much higher photocatalytic activity than SrBi_(2)A_(2)O_(9),which is due to its suitable crystal structure.
基金by the Fundamental Research Funds for Central Universities under Grant No 2010LKWL06the National Natural Science Foundation of China under Grant No 10947119the Youth Science Funds of China University of Mining and Technology under Grant No 2009A040。
文摘A first principles study using the full potential linearized augmented plane wave(FP-LAPW)method is applied to study the structural,electronic and optical properties of BiAlxGa1−xO3.The results show that the alloys become markedly hard as the Al concentration increases.The calculated structural parameters are in good agreement with the experimental data.The band structure and density of states are obtained,which indicate that BiAlxGa1−xO3 has an indirect band gap.Moreover,the optical properties are calculated and analyzed in detail.It is proposed that BiAl_(x)Ga_(1−x)O_(3) is a promising dielectric material.
基金by the Fundamental Research Funds for the Central Universities(No 2010LKWL06).
文摘The pseudo-potential plane wave(PP-PW)method with the generalized gradient approximation(GGA)is used to calculate the structural,electronic and optical properties of cubic and tetragonal BaZr_(x)Ti_(1−x)O_(3)(BZT)(x=0,0.25,0.5,0.75).The calculated structural parameters are found to be in good agreement with the experimental data.The energy band structure density of states(DOS)are obtained,which indicates that the Zr substitute can induce the band gap widening of BaTiO3.Furthermore,their optical properties are also calculated and analyzed in detail.It is shown that the dielectric imaginary part of BZT decreases as x(Zr concentration)increases.
