The plasma synthetic jet is a novel flow control approach which is currently being studied. In this paper its characteristic and control effect on supersonic flow is investigated both experimentally and numerically. I...The plasma synthetic jet is a novel flow control approach which is currently being studied. In this paper its characteristic and control effect on supersonic flow is investigated both experimentally and numerically. In the experiment, the formation of plasma synthetic jet and its propagation velocity in quiescent air are recorded and calculated with time resolved schlieren method. The jet velocity is up to 100 m/s and no remarkable difference has been found after changing discharge parameters. When applied in Mach 2 supersonic flow, an obvious shockwave can be observed. In the modeling of electrical heating, the arc domain is not defined as an initial condition with fixed temperature or pressure, but a source term with time-varying input power density, which is expected to better describe the influence of heating process. Velocity variation with different heating efficiencies is presented and discussed and a peak velocity of 850 m/s is achieved in still air with heating power density of 5.0 · 1012W/m3. For more details on the interaction between plasma synthetic jet and supersonic flow, the plasma synthetic jet induced shockwave and the disturbances in the boundary layer are numerically researched. All the results have demonstrated the control authority of plasma synthetic jet onto supersonic flow.展开更多
Background Tamsulosin, an alpha-1 receptor antagonist, has been demonstrated effective in promoting distal ureteral stone passage and in reducing pain associated with stone expulsion. This study aimed to evaluate the ...Background Tamsulosin, an alpha-1 receptor antagonist, has been demonstrated effective in promoting distal ureteral stone passage and in reducing pain associated with stone expulsion. This study aimed to evaluate the effect of tamsulosin in comparison with nifedipine and extracorporeal shock wave lithotripsy （ESWL） on the expulsion rate of distal ureteral stones at different sizes. Methods We assigned 314 patients to three categories： Ⅰ, the stone with maximal diameter of 4.0-5.9 mm; Ⅱ, 6.0-7.9 mm, and Ⅲ, 8.0-9.9 mm. Patients in each category were randomly subdivided into three treatment subgroups： group A （nifedipine group）, group B （tamsulosin group）, and group C （ESWL group）. Stone-free rate and the dose of analgesics were recorded weekly during the 4-week follow-up period. Results Three hundred and three patients completed the study. The results showed that nifedipine and tamsulosin treatments promoted a small （4-8 mm, categories Ⅰ and Ⅱ） stone expulsive rate that was comparable with ESWL treatment. Nonetheless, when the stone diameter was 8.0-9.9 mm, ESWL showed a greater stone free rate than nifedipine and tamsulosin treatments; no significant difference existed between the latter two therapies. Although the ESWL treatment group required the least analgesics, tamsulosin treatments required less pain medication than nifedipine （P 〈0.05）. Conclusions Tamsulosin treatment is recommended for patients with the stone diameter smaller than 8 mm because of its feasibility, effectiveness and safety. ESWL is more appropriate than tamsulosin therapy for the patients whose stones are larger than 8 mm.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51407197,11472306,11372352)
文摘The plasma synthetic jet is a novel flow control approach which is currently being studied. In this paper its characteristic and control effect on supersonic flow is investigated both experimentally and numerically. In the experiment, the formation of plasma synthetic jet and its propagation velocity in quiescent air are recorded and calculated with time resolved schlieren method. The jet velocity is up to 100 m/s and no remarkable difference has been found after changing discharge parameters. When applied in Mach 2 supersonic flow, an obvious shockwave can be observed. In the modeling of electrical heating, the arc domain is not defined as an initial condition with fixed temperature or pressure, but a source term with time-varying input power density, which is expected to better describe the influence of heating process. Velocity variation with different heating efficiencies is presented and discussed and a peak velocity of 850 m/s is achieved in still air with heating power density of 5.0 · 1012W/m3. For more details on the interaction between plasma synthetic jet and supersonic flow, the plasma synthetic jet induced shockwave and the disturbances in the boundary layer are numerically researched. All the results have demonstrated the control authority of plasma synthetic jet onto supersonic flow.
文摘Background Tamsulosin, an alpha-1 receptor antagonist, has been demonstrated effective in promoting distal ureteral stone passage and in reducing pain associated with stone expulsion. This study aimed to evaluate the effect of tamsulosin in comparison with nifedipine and extracorporeal shock wave lithotripsy （ESWL） on the expulsion rate of distal ureteral stones at different sizes. Methods We assigned 314 patients to three categories： Ⅰ, the stone with maximal diameter of 4.0-5.9 mm; Ⅱ, 6.0-7.9 mm, and Ⅲ, 8.0-9.9 mm. Patients in each category were randomly subdivided into three treatment subgroups： group A （nifedipine group）, group B （tamsulosin group）, and group C （ESWL group）. Stone-free rate and the dose of analgesics were recorded weekly during the 4-week follow-up period. Results Three hundred and three patients completed the study. The results showed that nifedipine and tamsulosin treatments promoted a small （4-8 mm, categories Ⅰ and Ⅱ） stone expulsive rate that was comparable with ESWL treatment. Nonetheless, when the stone diameter was 8.0-9.9 mm, ESWL showed a greater stone free rate than nifedipine and tamsulosin treatments; no significant difference existed between the latter two therapies. Although the ESWL treatment group required the least analgesics, tamsulosin treatments required less pain medication than nifedipine （P 〈0.05）. Conclusions Tamsulosin treatment is recommended for patients with the stone diameter smaller than 8 mm because of its feasibility, effectiveness and safety. ESWL is more appropriate than tamsulosin therapy for the patients whose stones are larger than 8 mm.
