Two-dimensional materials are widely considered to be highly promising for the development of photodetectors.To improve the performance of these devices,researchers often employ techniques such as defect engineering.H...Two-dimensional materials are widely considered to be highly promising for the development of photodetectors.To improve the performance of these devices,researchers often employ techniques such as defect engineering.Herein,pressure is employed as a clean and novel means to manipulate the structural and physical properties of EuSbTe_(3),an emerging two-dimensional semiconductor.The experimental results demonstrate that the structural phase transformation of EuSbTe_(3)occurs under pressure,with an increase in infrared reflectivity,a band gap closure,and a metallization at pressures.Combined with X-ray diffraction(XRD)and Raman characterizations,it is evident that the pressure-driven transition from semiconductor Pmmn phase to metallic Cmcm phase causes the disappearance of the charge density wave.Furthermore,at a mild pressure,approximately 2 GPa,the maximum photocurrent of EuSbTe_(3)is three times higher than that at ambient condition,suggesting an untapped potential for various practical applications.展开更多
In the current state-of-the-art,high-loss flow in the endwall significantly influences compressor performance.Therefore,the control of endwall corner separation in compressor blade rows is important to consider.Based ...In the current state-of-the-art,high-loss flow in the endwall significantly influences compressor performance.Therefore,the control of endwall corner separation in compressor blade rows is important to consider.Based on the previous research of the Blended Blade and End Wall(BBEW)technique,which can significantly reduce corner separation,in combination with a nonaxisymmetric endwall,the full-BBEW technique is proposed in this study to further reduce the separation in endwall region.The principle of the unchanged axial passage area is considered to derive the geometric method for this technique.Three models are further classified based on different geometric characteristics of this technique:the BBEW model,Inclining-Only End Wall(IOEW)model,and full-BBEW model.The most effective design of each model is then found by performing several optimizations at the design point and related numerical investigations over the entire operational conditions.Compared with the prototype,the total pressure loss coefficient decreases by 7%–9%in the optimized full-BBEW at the design point.Moreover,the aerodynamic blockage coefficient over the entire operational range decreases more than the other models,which shows its positive effect for diffusion.This approach has a larger decrease at negative incidence angles where the intersection of the boundary layer plays an important role in corner separation.The analysis shows that the blended blade profile enlarges the dihedral angle and creates a span-wise pressure gradient to move low momentum fluid towards the mainstream.Furthermore,the inclining hub geometry accelerates the accumulated flow in the corner downstream by increasing the pressure gradient.Overall,though losses in the mainstream grow,especially for large incidences,the full-BBEW technique effectively reduces the separation in corners.展开更多
In this paper we have given an analytic excitation solution of exploding wave in infinite elastic body with growing spherical inner boundary, and the convergence region of series in this solution determined. Some char...In this paper we have given an analytic excitation solution of exploding wave in infinite elastic body with growing spherical inner boundary, and the convergence region of series in this solution determined. Some characters of the displacement wave have also been discussed.展开更多
基金financially supported by the National Natural Science Foundation of China(No.U2130116)Shanghai Key Laboratory of Material Frontiers Research in Extreme Environments(MFree),China(No.22dz2260800)Shanghai Science and Technology Committee,China(No.22JC1410300)。
文摘Two-dimensional materials are widely considered to be highly promising for the development of photodetectors.To improve the performance of these devices,researchers often employ techniques such as defect engineering.Herein,pressure is employed as a clean and novel means to manipulate the structural and physical properties of EuSbTe_(3),an emerging two-dimensional semiconductor.The experimental results demonstrate that the structural phase transformation of EuSbTe_(3)occurs under pressure,with an increase in infrared reflectivity,a band gap closure,and a metallization at pressures.Combined with X-ray diffraction(XRD)and Raman characterizations,it is evident that the pressure-driven transition from semiconductor Pmmn phase to metallic Cmcm phase causes the disappearance of the charge density wave.Furthermore,at a mild pressure,approximately 2 GPa,the maximum photocurrent of EuSbTe_(3)is three times higher than that at ambient condition,suggesting an untapped potential for various practical applications.
基金sponsored by the National Natural Science Foundation of China(Nos.51676015 and 51976010)National Major Science and Technology Project of China(Nos.2017-II0006-0020 and 2017-II-0001-0013)Beijing Institute of Technology Research Fund Program for Young Scholars,China。
文摘In the current state-of-the-art,high-loss flow in the endwall significantly influences compressor performance.Therefore,the control of endwall corner separation in compressor blade rows is important to consider.Based on the previous research of the Blended Blade and End Wall(BBEW)technique,which can significantly reduce corner separation,in combination with a nonaxisymmetric endwall,the full-BBEW technique is proposed in this study to further reduce the separation in endwall region.The principle of the unchanged axial passage area is considered to derive the geometric method for this technique.Three models are further classified based on different geometric characteristics of this technique:the BBEW model,Inclining-Only End Wall(IOEW)model,and full-BBEW model.The most effective design of each model is then found by performing several optimizations at the design point and related numerical investigations over the entire operational conditions.Compared with the prototype,the total pressure loss coefficient decreases by 7%–9%in the optimized full-BBEW at the design point.Moreover,the aerodynamic blockage coefficient over the entire operational range decreases more than the other models,which shows its positive effect for diffusion.This approach has a larger decrease at negative incidence angles where the intersection of the boundary layer plays an important role in corner separation.The analysis shows that the blended blade profile enlarges the dihedral angle and creates a span-wise pressure gradient to move low momentum fluid towards the mainstream.Furthermore,the inclining hub geometry accelerates the accumulated flow in the corner downstream by increasing the pressure gradient.Overall,though losses in the mainstream grow,especially for large incidences,the full-BBEW technique effectively reduces the separation in corners.
文摘In this paper we have given an analytic excitation solution of exploding wave in infinite elastic body with growing spherical inner boundary, and the convergence region of series in this solution determined. Some characters of the displacement wave have also been discussed.
