An analysis was performed of the turbulent data obtained from Yucheng experimental station in the Shandong Province in 1984. [t is shown that at variant wind speed, the spectra of streamwise velocity remain similar an...An analysis was performed of the turbulent data obtained from Yucheng experimental station in the Shandong Province in 1984. [t is shown that at variant wind speed, the spectra of streamwise velocity remain similar and the intensity of wind fluctuations is proportional to wind speed in the downwind area of shelter belt. Therefore, we may decide the similarity of wind fluctuations by a speed scale and a length scale which is not correlated with stability, σu /V0 = F(X / H). The -5/3 power range of temperature spectra extends to lower frequency. The variation of ratio σ0 /T. with stability becomes σ0 / T . = C(X / H)( - Z / L)-1/3 . There is not such an extension of -5 / 3 power range in the humidity spectra.展开更多
The Mg-air batteries face limitations with pronounced hydrogen evolution and low anodic utilization efficiency from Mg anodes in conventional NaCl electrolytes.The corrosion performance,surface composition,and dischar...The Mg-air batteries face limitations with pronounced hydrogen evolution and low anodic utilization efficiency from Mg anodes in conventional NaCl electrolytes.The corrosion performance,surface composition,and discharge properties of commercial purity Mg anodes were thoroughly investigated in KNO_(3)electrolytes with and without sodium 5-sulfosalicylate and compared to NaCl electrolyte.The addition of sodium 5-sulfosalicylate to KNO_(3)-based electrolyte results in efficient inhibition of H_(2)evolution,consequently enhancing anodic utilization efficiency to 84%and specific capacity to 1844 mAh/g,compared to NaCl(24%and 534 mAh/g,respectively)under discharge condition of 10 mA/cm^(2)in half cell.Furthermore,the chelating ability of sodium 5-sulfosalicylate can significantly improve the Mg surface dissolution kinetics and discharge product deposition rate at the Mg anode/electrolyte interface,yielding formation of a thinner discharge layer as confirmed by time-of-flight secondary ion mass spectrometry.The discharge voltage is increased to 1.60 V,compared to 1.35 V in KNO_(3)at 0.5 mA/cm^(2)in full cell.However,higher concentration of sodium 5-sulfosalicylate can accelerate Mg anode dissolution,impeding the improvement of anodic utilization efficiency,specific capacity,and energy density.Hence,determining optimal additive concentration and current density is crucial for enhancing the discharge properties of Mg-air batteries and mitigating excessive Mg dissolution in chloride-free electrolytes.展开更多
The objective of the present investigation is to predict the nonlinear buckling and postbuckling characteristics of cylindrical shear deformable nanoshells with and without initial imperfection under hydrostatic press...The objective of the present investigation is to predict the nonlinear buckling and postbuckling characteristics of cylindrical shear deformable nanoshells with and without initial imperfection under hydrostatic pressure load in the presence of surface free energy effects.To this end, Gurtin-Murdoch elasticity theory is implemented into the irst-order shear deformation shell theory to develop a size-dependent shell model which has an excellent capability to take surface free energy effects into account. A linear variation through the shell thickness is assumed for the normal stress component of the bulk to satisfy the equilibrium conditions on the surfaces of nanoshell. On the basis of variational approach and using von Karman-Donnell-type of kinematic nonlinearity, the non-classical governing differential equations are derived. Then a boundary layer theory of shell buckling is employed incorporating the effects of surface free energy in conjunction with nonlinear prebuckling deformations, large delections in the postbuckling domain and initial geometric imperfection. Finally, an eficient solution methodology based on a two-stepped singular perturbation technique is put into use in order to obtain the critical buckling loads and postbuckling equilibrium paths corresponding to various geometric parameters. It is demonstrated that the surface free energy effects cause increases in both the critical buckling pressure and critical end-shortening of a nanoshell made of silicon.展开更多
文摘An analysis was performed of the turbulent data obtained from Yucheng experimental station in the Shandong Province in 1984. [t is shown that at variant wind speed, the spectra of streamwise velocity remain similar and the intensity of wind fluctuations is proportional to wind speed in the downwind area of shelter belt. Therefore, we may decide the similarity of wind fluctuations by a speed scale and a length scale which is not correlated with stability, σu /V0 = F(X / H). The -5/3 power range of temperature spectra extends to lower frequency. The variation of ratio σ0 /T. with stability becomes σ0 / T . = C(X / H)( - Z / L)-1/3 . There is not such an extension of -5 / 3 power range in the humidity spectra.
基金the China Scholarship Council(CSC)for funding(No.202209350006).
文摘The Mg-air batteries face limitations with pronounced hydrogen evolution and low anodic utilization efficiency from Mg anodes in conventional NaCl electrolytes.The corrosion performance,surface composition,and discharge properties of commercial purity Mg anodes were thoroughly investigated in KNO_(3)electrolytes with and without sodium 5-sulfosalicylate and compared to NaCl electrolyte.The addition of sodium 5-sulfosalicylate to KNO_(3)-based electrolyte results in efficient inhibition of H_(2)evolution,consequently enhancing anodic utilization efficiency to 84%and specific capacity to 1844 mAh/g,compared to NaCl(24%and 534 mAh/g,respectively)under discharge condition of 10 mA/cm^(2)in half cell.Furthermore,the chelating ability of sodium 5-sulfosalicylate can significantly improve the Mg surface dissolution kinetics and discharge product deposition rate at the Mg anode/electrolyte interface,yielding formation of a thinner discharge layer as confirmed by time-of-flight secondary ion mass spectrometry.The discharge voltage is increased to 1.60 V,compared to 1.35 V in KNO_(3)at 0.5 mA/cm^(2)in full cell.However,higher concentration of sodium 5-sulfosalicylate can accelerate Mg anode dissolution,impeding the improvement of anodic utilization efficiency,specific capacity,and energy density.Hence,determining optimal additive concentration and current density is crucial for enhancing the discharge properties of Mg-air batteries and mitigating excessive Mg dissolution in chloride-free electrolytes.
文摘The objective of the present investigation is to predict the nonlinear buckling and postbuckling characteristics of cylindrical shear deformable nanoshells with and without initial imperfection under hydrostatic pressure load in the presence of surface free energy effects.To this end, Gurtin-Murdoch elasticity theory is implemented into the irst-order shear deformation shell theory to develop a size-dependent shell model which has an excellent capability to take surface free energy effects into account. A linear variation through the shell thickness is assumed for the normal stress component of the bulk to satisfy the equilibrium conditions on the surfaces of nanoshell. On the basis of variational approach and using von Karman-Donnell-type of kinematic nonlinearity, the non-classical governing differential equations are derived. Then a boundary layer theory of shell buckling is employed incorporating the effects of surface free energy in conjunction with nonlinear prebuckling deformations, large delections in the postbuckling domain and initial geometric imperfection. Finally, an eficient solution methodology based on a two-stepped singular perturbation technique is put into use in order to obtain the critical buckling loads and postbuckling equilibrium paths corresponding to various geometric parameters. It is demonstrated that the surface free energy effects cause increases in both the critical buckling pressure and critical end-shortening of a nanoshell made of silicon.
