The dilaton in Weyl-Scale induced gravitational theory is regarded as a candidate of dark energy. When the potential of dilaton field is taken as the form Wσ ＋ σ^2e^-βσ2, that there exist attractor solutions to t...The dilaton in Weyl-Scale induced gravitational theory is regarded as a candidate of dark energy. When the potential of dilaton field is taken as the form Wσ ＋ σ^2e^-βσ2, that there exist attractor solutions to the canonical dilatonic dark energy model and the phontam model, and these attractors correspond to an equation of state ω = -1 and a cosmic density parameter Ωσ = 1, which are important features for a dark energy model and can fit with the current observations. We find a sufficient condition of the existence of a late time de Sitter attractor. The attractor behaviors, the evolutions of the state parameter ω and the cosmic density parameter Ω, the evolution of X （σ/σ0） and Y （σ/σ0^2） with respect to N（ln a）are shown numerically.展开更多
Complexity and implementation of design norms in Cameroon required a proven foreign expertise, but nowadays local engineers are mastering modern construction techniques. They are turning to pile foundations to solve t...Complexity and implementation of design norms in Cameroon required a proven foreign expertise, but nowadays local engineers are mastering modern construction techniques. They are turning to pile foundations to solve the problem of construction sites on weak soils. The objective of this work is to present the trend of the country pile-driving capacity of some foundations design and construction companies. The proposed analytical method is based on Finite Element Method and on the theory of wave＇s propagation and transmission along the pile taking into account experimental data on the construction site. The proposed method is validated through recorded data during the construction of the Mungo Bridge in Cameroon, and obtained analytical results are in agreement with experimental results.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.10573012, 10575068)the Science Foundation of Shanghai Municipal Commission of Science and Technology (Grant No.04dz05905)
文摘The dilaton in Weyl-Scale induced gravitational theory is regarded as a candidate of dark energy. When the potential of dilaton field is taken as the form Wσ ＋ σ^2e^-βσ2, that there exist attractor solutions to the canonical dilatonic dark energy model and the phontam model, and these attractors correspond to an equation of state ω = -1 and a cosmic density parameter Ωσ = 1, which are important features for a dark energy model and can fit with the current observations. We find a sufficient condition of the existence of a late time de Sitter attractor. The attractor behaviors, the evolutions of the state parameter ω and the cosmic density parameter Ω, the evolution of X （σ/σ0） and Y （σ/σ0^2） with respect to N（ln a）are shown numerically.
文摘Complexity and implementation of design norms in Cameroon required a proven foreign expertise, but nowadays local engineers are mastering modern construction techniques. They are turning to pile foundations to solve the problem of construction sites on weak soils. The objective of this work is to present the trend of the country pile-driving capacity of some foundations design and construction companies. The proposed analytical method is based on Finite Element Method and on the theory of wave＇s propagation and transmission along the pile taking into account experimental data on the construction site. The proposed method is validated through recorded data during the construction of the Mungo Bridge in Cameroon, and obtained analytical results are in agreement with experimental results.
