The bending moment acting on the overhung shaft of a gas-sparged vessel stirred by a Rushton turbine,as one of the results of fluid and structure interactions in stirred vessels,was measured using a moment sensor equi...The bending moment acting on the overhung shaft of a gas-sparged vessel stirred by a Rushton turbine,as one of the results of fluid and structure interactions in stirred vessels,was measured using a moment sensor equipped with digital telemetry.An analysis of the shaft bending moment amplitude shows that the amplitude distribution of the bending moment,which indicates the elasticity nature of shaft material against bending deformation,follows the Weibull distribution.The trends of amplitude mean,standard deviation and peak deviation characteristics manifest an "S" shape versus gas flow.The "S" trend of the relative mean bending moment over gas flow rate,depending on the flow regime in gas-liquid stirred vessels,resulted from the competition among the nonuniformity of bubbly flow around the impeller,the formation of gas cavities behind the blades,and the gas direct impact on the impeller when gas is introduced.A further analysis of the bending moment power spectral density shows that the rather low frequency and speed frequency are evident.The low-frequency contribution to bending moment fluctuation peaks in the complete dispersion regime.展开更多
We demonstrate the effects of electron-electron （e-e） interactions in monolayer graphene quantum capacitors. Ultrathin yttrium oxide showed excellent per-formance as the dielectric layer in top-gate device geometry....We demonstrate the effects of electron-electron （e-e） interactions in monolayer graphene quantum capacitors. Ultrathin yttrium oxide showed excellent per-formance as the dielectric layer in top-gate device geometry. The structure and dielectric constant of the yttrium oxide layers have been carefully studied. The inverse compressibility retrieved from the quantum capacitance agreed fairly well with the theoretical predictions for the e--e interactions in monolayer graphene at different temperatures. We found that electron-hole puddles played a significant role in the low-density carrier region in graphene. By considering the temperature-dependent charge fluctuation, we established a model to explain the round-off effect originating from the e-e interactions in monolayer graphene near the Dirac point.展开更多
文摘The bending moment acting on the overhung shaft of a gas-sparged vessel stirred by a Rushton turbine,as one of the results of fluid and structure interactions in stirred vessels,was measured using a moment sensor equipped with digital telemetry.An analysis of the shaft bending moment amplitude shows that the amplitude distribution of the bending moment,which indicates the elasticity nature of shaft material against bending deformation,follows the Weibull distribution.The trends of amplitude mean,standard deviation and peak deviation characteristics manifest an "S" shape versus gas flow.The "S" trend of the relative mean bending moment over gas flow rate,depending on the flow regime in gas-liquid stirred vessels,resulted from the competition among the nonuniformity of bubbly flow around the impeller,the formation of gas cavities behind the blades,and the gas direct impact on the impeller when gas is introduced.A further analysis of the bending moment power spectral density shows that the rather low frequency and speed frequency are evident.The low-frequency contribution to bending moment fluctuation peaks in the complete dispersion regime.
文摘We demonstrate the effects of electron-electron （e-e） interactions in monolayer graphene quantum capacitors. Ultrathin yttrium oxide showed excellent per-formance as the dielectric layer in top-gate device geometry. The structure and dielectric constant of the yttrium oxide layers have been carefully studied. The inverse compressibility retrieved from the quantum capacitance agreed fairly well with the theoretical predictions for the e--e interactions in monolayer graphene at different temperatures. We found that electron-hole puddles played a significant role in the low-density carrier region in graphene. By considering the temperature-dependent charge fluctuation, we established a model to explain the round-off effect originating from the e-e interactions in monolayer graphene near the Dirac point.
