The entropy analysis of viscoelastic fluid obeying the simplified Phan-ThienTanner(SPTT)model with variable thermophysical properties are obtained for laminar,steady state and fully developed Couette-Poiseuille flow.T...The entropy analysis of viscoelastic fluid obeying the simplified Phan-ThienTanner(SPTT)model with variable thermophysical properties are obtained for laminar,steady state and fully developed Couette-Poiseuille flow.The homotopy perturbation method(HPM)allows us to solve nonlinear momentum and energy differential equations.The Reynold’s model is used to describe the temperature dependency of thermophysical properties.Results indicate that the increase of the group parameter(Br=U)and the Brinkman number(Br)which show the power of viscous dissipation effect;increases the entropy generation while increasing fluid elasticity(εDe2)decreases the generated entropy.Increasing the Reynolds variational parameter(a)which control the level of temperature dependence of physical properties attenuate entropy generation when moving plate and applied pressure gradient have the opposite direction and decreases entropy generation when moving plate and applied pressure gradient have the same direction or both plates are at rest.Also,increasing elasticity reduces the difference between variable and constant thermophysical properties cases.These results may give guidelines for cost optimization in industrial processes.展开更多
This paper deals with finite element study of the scanning induction heating of the magnetic steel sheets in transversal flux devices,taking into account the magnetic nonlinearity and the dependence on temperature of ...This paper deals with finite element study of the scanning induction heating of the magnetic steel sheets in transversal flux devices,taking into account the magnetic nonlinearity and the dependence on temperature of steel properties.The decrease of the non-uniformity of the transversal profile of sheet heating as effect of the magnetic or electromagnetic screening of the sheet lateral sides was proved.展开更多
Sm22Co78/Fe65Co35/Sm22Co78/Fe65Co35 multilayer films were prepared by magnetron sputtering. The temperature dependence of coercivity (Hc), remanence (Mr) and reduced remanence (Mr/Ms) has been measured. The coercivit...Sm22Co78/Fe65Co35/Sm22Co78/Fe65Co35 multilayer films were prepared by magnetron sputtering. The temperature dependence of coercivity (Hc), remanence (Mr) and reduced remanence (Mr/Ms) has been measured. The coercivity decreases with increasing of temperature. The remanence decreases with increasing the temperature from 26 to 100℃, and then increases with continuously increasing the temperature from 100 to 150℃. The reduced remanence increases with increasing the temperature.展开更多
The temperature-dependent photoluminescence （PL） spectra of Baln204, prepared by coprecipitation, are measured and discussed. Aside from the reported 3.02-eV violet emission, the 1.81-eV yellow emission in- volved w...The temperature-dependent photoluminescence （PL） spectra of Baln204, prepared by coprecipitation, are measured and discussed. Aside from the reported 3.02-eV violet emission, the 1.81-eV yellow emission in- volved with oxygen vacancy is also observed at room temperature wherein the deep donor level is at 1.2 eV. With the temperature increasing, the peak energies for both emissions show a red shift. Moreover, the yel- low emission intensity decreases while the violet emission intensity increases. The temperature dependence of the yellow emission intensity fits very well into the one-step quenching process equation, indicating a fitted activation energy at 19.2 meV.展开更多
文摘The entropy analysis of viscoelastic fluid obeying the simplified Phan-ThienTanner(SPTT)model with variable thermophysical properties are obtained for laminar,steady state and fully developed Couette-Poiseuille flow.The homotopy perturbation method(HPM)allows us to solve nonlinear momentum and energy differential equations.The Reynold’s model is used to describe the temperature dependency of thermophysical properties.Results indicate that the increase of the group parameter(Br=U)and the Brinkman number(Br)which show the power of viscous dissipation effect;increases the entropy generation while increasing fluid elasticity(εDe2)decreases the generated entropy.Increasing the Reynolds variational parameter(a)which control the level of temperature dependence of physical properties attenuate entropy generation when moving plate and applied pressure gradient have the opposite direction and decreases entropy generation when moving plate and applied pressure gradient have the same direction or both plates are at rest.Also,increasing elasticity reduces the difference between variable and constant thermophysical properties cases.These results may give guidelines for cost optimization in industrial processes.
文摘This paper deals with finite element study of the scanning induction heating of the magnetic steel sheets in transversal flux devices,taking into account the magnetic nonlinearity and the dependence on temperature of steel properties.The decrease of the non-uniformity of the transversal profile of sheet heating as effect of the magnetic or electromagnetic screening of the sheet lateral sides was proved.
文摘Sm22Co78/Fe65Co35/Sm22Co78/Fe65Co35 multilayer films were prepared by magnetron sputtering. The temperature dependence of coercivity (Hc), remanence (Mr) and reduced remanence (Mr/Ms) has been measured. The coercivity decreases with increasing of temperature. The remanence decreases with increasing the temperature from 26 to 100℃, and then increases with continuously increasing the temperature from 100 to 150℃. The reduced remanence increases with increasing the temperature.
基金supported by the National "973" Program of China (No.2010CB933700)the National Natural Science Foundation of China (Nos.10804117 and 60221502)+1 种基金the Shanghai Natural Science Foundation(No.08ZR1421900)the Knowledge Innovation Program of the Chinese Academy of Sciences
文摘The temperature-dependent photoluminescence （PL） spectra of Baln204, prepared by coprecipitation, are measured and discussed. Aside from the reported 3.02-eV violet emission, the 1.81-eV yellow emission in- volved with oxygen vacancy is also observed at room temperature wherein the deep donor level is at 1.2 eV. With the temperature increasing, the peak energies for both emissions show a red shift. Moreover, the yel- low emission intensity decreases while the violet emission intensity increases. The temperature dependence of the yellow emission intensity fits very well into the one-step quenching process equation, indicating a fitted activation energy at 19.2 meV.
