Based on Reddy higher-order shear deformation theory, a general refined shell theory suitable to nonlinear analysis of tire structure is developed in this paper. The piece-wise Rayleigh-Ritz procedure and Bezier polyn...Based on Reddy higher-order shear deformation theory, a general refined shell theory suitable to nonlinear analysis of tire structure is developed in this paper. The piece-wise Rayleigh-Ritz procedure and Bezier polynomials are applied to analyze deformations and stress distributions of the multlayered tire subjected to uniform inflation in detail. Furthermore, 3-dimension FEM analysis of laminated tire by standard software ANSYS is adopted to compare with the present model. It is demonstrated that both two solutions are in fairly good agreement.展开更多
The authors investigate the influence of a harmonic potential and random perturbations on the nonlinear Schr6dinger equations. The local and global well-posedness are proved with values in the space ∑（R^n）={f E HI...The authors investigate the influence of a harmonic potential and random perturbations on the nonlinear Schr6dinger equations. The local and global well-posedness are proved with values in the space ∑（R^n）={f E HI（R^n）, ｜·｜f ∈ L^2（R^n）}. When the nonlinearity is focusing and L2-supercritical, the authors give sufficient conditions for the solutions to blow up in finite time for both confining and repulsive potential. Especially for the repulsive case, the solution to the deterministic equation with the initial data satisfying the stochastic blow-up condition will also blow up in finite time. Thus, compared with the deterministic equation for the repulsive case, the blow-up condition is stronger on average, and depends on the regularity of the noise. If φ = 0, our results coincide with the ones for the deterministic equation.展开更多
Based on eddy covariance measurements over two kinds of land surfaces(a degraded grassland and a maize cropland)in a semiarid area of China in 2005 and 2008,the effects of different gap filling methods,energy balance ...Based on eddy covariance measurements over two kinds of land surfaces(a degraded grassland and a maize cropland)in a semiarid area of China in 2005 and 2008,the effects of different gap filling methods,energy balance closure and friction velocity threshold(u*)on annual net ecosystem exchange(NEE)were analyzed.Six gap filling methods,including mean diurnal variation(MDV),marginal distribution sampling(MDS),and nonlinear regressions method,were investigated by generating secondary datasets with four different artificial gap lengths(ranging in length from single half-hours to 12 consecutive days).The MDS generally showed a good overall performance especially for long gaps,with an annual sum bias error less than 5 g C m-2 yr-1.There was a large positive annual sum bias error for nonlinear regressions,indicating an overestimate on net ecosystem respiration.The offset in the annual sum NEE for four nonlinear regressions was from 8.0 to 30.8 g C m-2 yr-1.As soil water content was a limiting factor in the semiarid area,the nonlinear regressions considering both soil temperature and soil water content as controlling variables had a better performance than others.The performance of MDV was better in daytime than in nighttime,with an annual sum bias error falling between-2.6 and-13.4 g C m-2 yr-1.Overall,the accuracy of the gap filling method was dependent on the type of the land surface,gap length,and the time of day when the data gap occurred.The energy balance ratio for the two ecosystems was nearly 80%.Turbulent intensity had a large impact on energy balance ratio.Low energy balance ratio was observed under low friction velocity during the night.When there was a large fetch distance in a wind direction,a low energy balance ratio was caused by mismatch of the footprints between the available energy and turbulent fluxes.The effect of energy balance correction on CO2 flux was evaluated by assuming the imbalance caused by the underestimation of sensible heat flux and latent heat flux.The results showed an average increase of 10 g C m-2 yr-1 for annual NEE in both ecosystems with an energy balance correction.On the other hand,the u*threshold also have a large impact on annual sum NEE.Net carbon emission increased 37.5 g C m-2 yr-1 as u*threshold increased from 0.1 to 0.2 m s-1,indicating a large impact of imposing u*threshold on net ecosystem carbon exchange.展开更多
In this paper, a periodic difference equation with saturable nonlinearity is considered. Using the linking theorem in combination with periodic approximations, we establish sufficient conditions on the nonexistence an...In this paper, a periodic difference equation with saturable nonlinearity is considered. Using the linking theorem in combination with periodic approximations, we establish sufficient conditions on the nonexistence and on the existence of homoclinic solutions. Our results not only solve an open problem proposed by Pankov, but also greatly improve some existing ones even for some special cases.展开更多
文摘Based on Reddy higher-order shear deformation theory, a general refined shell theory suitable to nonlinear analysis of tire structure is developed in this paper. The piece-wise Rayleigh-Ritz procedure and Bezier polynomials are applied to analyze deformations and stress distributions of the multlayered tire subjected to uniform inflation in detail. Furthermore, 3-dimension FEM analysis of laminated tire by standard software ANSYS is adopted to compare with the present model. It is demonstrated that both two solutions are in fairly good agreement.
基金supported by the National Natural Science Foundation of China (Nos. 10871175,10931007,10901137)the Zhejiang Provincial Natural Science Foundation of China (No. Z6100217)the Specialized ResearchFund for the Doctoral Program of Higher Education (No. 20090101120005)
文摘The authors investigate the influence of a harmonic potential and random perturbations on the nonlinear Schr6dinger equations. The local and global well-posedness are proved with values in the space ∑（R^n）={f E HI（R^n）, ｜·｜f ∈ L^2（R^n）}. When the nonlinearity is focusing and L2-supercritical, the authors give sufficient conditions for the solutions to blow up in finite time for both confining and repulsive potential. Especially for the repulsive case, the solution to the deterministic equation with the initial data satisfying the stochastic blow-up condition will also blow up in finite time. Thus, compared with the deterministic equation for the repulsive case, the blow-up condition is stronger on average, and depends on the regularity of the noise. If φ = 0, our results coincide with the ones for the deterministic equation.
基金supported by the National Natural Science Foundation of China(Grant Nos.41275023,41021004))Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA05110102)
文摘Based on eddy covariance measurements over two kinds of land surfaces(a degraded grassland and a maize cropland)in a semiarid area of China in 2005 and 2008,the effects of different gap filling methods,energy balance closure and friction velocity threshold(u*)on annual net ecosystem exchange(NEE)were analyzed.Six gap filling methods,including mean diurnal variation(MDV),marginal distribution sampling(MDS),and nonlinear regressions method,were investigated by generating secondary datasets with four different artificial gap lengths(ranging in length from single half-hours to 12 consecutive days).The MDS generally showed a good overall performance especially for long gaps,with an annual sum bias error less than 5 g C m-2 yr-1.There was a large positive annual sum bias error for nonlinear regressions,indicating an overestimate on net ecosystem respiration.The offset in the annual sum NEE for four nonlinear regressions was from 8.0 to 30.8 g C m-2 yr-1.As soil water content was a limiting factor in the semiarid area,the nonlinear regressions considering both soil temperature and soil water content as controlling variables had a better performance than others.The performance of MDV was better in daytime than in nighttime,with an annual sum bias error falling between-2.6 and-13.4 g C m-2 yr-1.Overall,the accuracy of the gap filling method was dependent on the type of the land surface,gap length,and the time of day when the data gap occurred.The energy balance ratio for the two ecosystems was nearly 80%.Turbulent intensity had a large impact on energy balance ratio.Low energy balance ratio was observed under low friction velocity during the night.When there was a large fetch distance in a wind direction,a low energy balance ratio was caused by mismatch of the footprints between the available energy and turbulent fluxes.The effect of energy balance correction on CO2 flux was evaluated by assuming the imbalance caused by the underestimation of sensible heat flux and latent heat flux.The results showed an average increase of 10 g C m-2 yr-1 for annual NEE in both ecosystems with an energy balance correction.On the other hand,the u*threshold also have a large impact on annual sum NEE.Net carbon emission increased 37.5 g C m-2 yr-1 as u*threshold increased from 0.1 to 0.2 m s-1,indicating a large impact of imposing u*threshold on net ecosystem carbon exchange.
基金supported partially by the Specialized Fund for the Doctoral Program of Higher Eduction (Grant No.20071078001)Key Project of National Natural Science Foundation of China (Grant No. 11031002)+1 种基金Natural Science and Engineering Research Council of Canada (NSERC)Project of Scientific Research Innovation Academic Group for the Education System of Guangzhou City
文摘In this paper, a periodic difference equation with saturable nonlinearity is considered. Using the linking theorem in combination with periodic approximations, we establish sufficient conditions on the nonexistence and on the existence of homoclinic solutions. Our results not only solve an open problem proposed by Pankov, but also greatly improve some existing ones even for some special cases.
