We analyze the shock wave refraction in a spatially developing shocked mixing layer by means of direct numerical simulation.Both regular and Mach reflections can occur depending on the relative strength of the induced...We analyze the shock wave refraction in a spatially developing shocked mixing layer by means of direct numerical simulation.Both regular and Mach reflections can occur depending on the relative strength of the induced shock wave over the vorticity of interacting vortex in the mixing layer.The stronger incident shock wave frequently refracts Mach reflection.The shock polar diagram is used to determine the shock wave refraction patterns.Moreover,the vortices are deformed and compressed by the shock wave,and their vorticities are increased.The interaction of shock wave and coherent structure can be helpful to enhance the mixing process.展开更多
Four kinds of presumed probability-density-function (PDF) models for non-premixed turbulent combustion are evaluated in flames with various stoichiometric mixture fractions by using large eddy simulation (LES).The LES...Four kinds of presumed probability-density-function (PDF) models for non-premixed turbulent combustion are evaluated in flames with various stoichiometric mixture fractions by using large eddy simulation (LES).The LES code is validated by the experimental data of a classical turbulent jet flame (Sandia flame D).The mean and rms temperatures obtained by the presumed PDF models are compared with the LES results.The β-function model achieves a good prediction for different flames.The predicted rms temperature by using the double-δ function model is very small and unphysical in the vicinity of the maximum mean temperature.The clip-Gaussian model and the multi-δ function model make a worse prediction of the extremely fuel-rich or fuel-lean side due to the clip at the boundary of the mixture fraction space.The results also show that the overall prediction performance of presumed PDF models is better at mediate stoichiometric mixture fractions than that at very small or very large ones.展开更多
Turbulent flow over rough walls is investigated through acoustic doppler velocimeter measurements.Smooth rods with a diameter of 6 mm are used as roughness elements.The rods are arranged at the channel bottom wall in ...Turbulent flow over rough walls is investigated through acoustic doppler velocimeter measurements.Smooth rods with a diameter of 6 mm are used as roughness elements.The rods are arranged at the channel bottom wall in three ways:longitudinally(along the flow direction);transversely(orthogonally to flow direction);and mesh-shaped(in a staggered mesh).The transverse roughness elements produce higher disturbance and flow drag than longitudinal roughness.Both turbulence intensity and flow drag for mesh-shaped roughness are not significantly different from those of transverse roughness,indicating that the transverse roughness elements mainly affect turbulence characteristics.Both turbulence intensity and flow drag are greatest for transverse rough walls at w/k=7;likewise,both increase with decreasing w/k for longitudinal rough walls.Compared with channel flow over a smooth wall,the turbulence intensity increases considerably,while the flow drag only increases slightly when w/k is small for the three arrangements.This is beneficial for enhancing heat transfer and mixing in channel flows with relatively small flow resistance.展开更多
An n-TiO_(2)/n−Si isotype heterojunction is fabricated by depositing TiO_(2) thin films onto n−Si substrates.Obvious photovoltaic behaviors are observed in this isotype heterojunction.The open circuit voltage and shor...An n-TiO_(2)/n−Si isotype heterojunction is fabricated by depositing TiO_(2) thin films onto n−Si substrates.Obvious photovoltaic behaviors are observed in this isotype heterojunction.The open circuit voltage and short circuit current of the heterojunction can reach 123 mV and 20µA/cm^(2),respectively.The mechanism for the photovoltaic behaviors can be understood in terms of the band alignment of the heterojunction.The results reported may provide a feasible route to easily available and low-cost isotyped photovoltaic devices.展开更多
Objective: To assess the efficacy and safety of Bufei Jiedu(BFJD) Granules as adjuvant therapy for patients with multidrug-resistant pulmonary tuberculosis(MDR-PTB). Methods: A large-scale, multi-center, double-blinde...Objective: To assess the efficacy and safety of Bufei Jiedu(BFJD) Granules as adjuvant therapy for patients with multidrug-resistant pulmonary tuberculosis(MDR-PTB). Methods: A large-scale, multi-center, double-blinded, and randomized controlled trial was conducted in 18 sentinel hospitals in China from December 2012 to December 2016. A total of 312 MDR-PTB patients were randomly assigned to BFJD Granules or placebo groups(1:1) using a stratified randomization method, which both received the long-course chemotherapy regimen for 18 months(6 Am-Lfx-P-Z-Pto, 12 Lfx-P-Z-Pto). Meanwhile, patients in both groups also received BFJD Granules or placebo twice a day for a total of 18 months, respectively. The primary outcome was cure rate. The secondary outcomes included time to sputum-culture conversion, changes in lung cavities and quality of life(QoL) of patients. Adverse reactions were monitored during and after the trial. Results: A total of 216 cases completed the trial, 111 in the BFJD Granules group and 105 in the placebo group. BFJD Granules, as adjuvant treatment, increased the cure rate by 13.6% at the end of treatment, compared with the placebo(58.4% vs. 44.8%, P=0.02), and accelerated the median time to sputum-culture conversion(5 months vs. 11 months). The cavity closure rate of the BFJD Granules group(50.6%, 43/85) was higher than that of the placebo group(32.1%, 26/81;P=0.02) in patients who completed the treatment. At the end of the intensive treatment, according to the 36-item Short Form, the BFJD Granules significantly improved physical functioning, general health, and vitality of patients relative to the placebo group(all P<0.01). Overall, the death rates in the two groups were not significantly different;5.1%(8/156) in the BFJD Granules group and 2.6%(4/156) in the placebo group. Conclusions: Supplementing BFJD Granules with the long-course chemotherapy regimen significantly increased the cure rate and cavity closure rate, and rapidly improved QoL of patients with MDR-PTB(Registration No. ChiCTR-TRC-12002850)展开更多
文摘We analyze the shock wave refraction in a spatially developing shocked mixing layer by means of direct numerical simulation.Both regular and Mach reflections can occur depending on the relative strength of the induced shock wave over the vorticity of interacting vortex in the mixing layer.The stronger incident shock wave frequently refracts Mach reflection.The shock polar diagram is used to determine the shock wave refraction patterns.Moreover,the vortices are deformed and compressed by the shock wave,and their vorticities are increased.The interaction of shock wave and coherent structure can be helpful to enhance the mixing process.
文摘Four kinds of presumed probability-density-function (PDF) models for non-premixed turbulent combustion are evaluated in flames with various stoichiometric mixture fractions by using large eddy simulation (LES).The LES code is validated by the experimental data of a classical turbulent jet flame (Sandia flame D).The mean and rms temperatures obtained by the presumed PDF models are compared with the LES results.The β-function model achieves a good prediction for different flames.The predicted rms temperature by using the double-δ function model is very small and unphysical in the vicinity of the maximum mean temperature.The clip-Gaussian model and the multi-δ function model make a worse prediction of the extremely fuel-rich or fuel-lean side due to the clip at the boundary of the mixture fraction space.The results also show that the overall prediction performance of presumed PDF models is better at mediate stoichiometric mixture fractions than that at very small or very large ones.
基金by the National Natural Science Foundation of China under Grant No 50876053。
文摘Turbulent flow over rough walls is investigated through acoustic doppler velocimeter measurements.Smooth rods with a diameter of 6 mm are used as roughness elements.The rods are arranged at the channel bottom wall in three ways:longitudinally(along the flow direction);transversely(orthogonally to flow direction);and mesh-shaped(in a staggered mesh).The transverse roughness elements produce higher disturbance and flow drag than longitudinal roughness.Both turbulence intensity and flow drag for mesh-shaped roughness are not significantly different from those of transverse roughness,indicating that the transverse roughness elements mainly affect turbulence characteristics.Both turbulence intensity and flow drag are greatest for transverse rough walls at w/k=7;likewise,both increase with decreasing w/k for longitudinal rough walls.Compared with channel flow over a smooth wall,the turbulence intensity increases considerably,while the flow drag only increases slightly when w/k is small for the three arrangements.This is beneficial for enhancing heat transfer and mixing in channel flows with relatively small flow resistance.
基金Supported by the National Natural Science Foundation of China under Grant No 60907046.
文摘An n-TiO_(2)/n−Si isotype heterojunction is fabricated by depositing TiO_(2) thin films onto n−Si substrates.Obvious photovoltaic behaviors are observed in this isotype heterojunction.The open circuit voltage and short circuit current of the heterojunction can reach 123 mV and 20µA/cm^(2),respectively.The mechanism for the photovoltaic behaviors can be understood in terms of the band alignment of the heterojunction.The results reported may provide a feasible route to easily available and low-cost isotyped photovoltaic devices.
基金Supported by National Major Science and Technology Projects of Infectious Diseases(Nos.2008ZX10005011 and 2012ZX10005-008)Traditional Chinese Medicine Innovation Team of Shanghai Municipal Health Commission(No.2022CX010)Three-Year Action Plan for Strengthening the Construction of the Public Health System in Shanghai(2023–2025,No.GWVI-11.1-08)。
文摘Objective: To assess the efficacy and safety of Bufei Jiedu(BFJD) Granules as adjuvant therapy for patients with multidrug-resistant pulmonary tuberculosis(MDR-PTB). Methods: A large-scale, multi-center, double-blinded, and randomized controlled trial was conducted in 18 sentinel hospitals in China from December 2012 to December 2016. A total of 312 MDR-PTB patients were randomly assigned to BFJD Granules or placebo groups(1:1) using a stratified randomization method, which both received the long-course chemotherapy regimen for 18 months(6 Am-Lfx-P-Z-Pto, 12 Lfx-P-Z-Pto). Meanwhile, patients in both groups also received BFJD Granules or placebo twice a day for a total of 18 months, respectively. The primary outcome was cure rate. The secondary outcomes included time to sputum-culture conversion, changes in lung cavities and quality of life(QoL) of patients. Adverse reactions were monitored during and after the trial. Results: A total of 216 cases completed the trial, 111 in the BFJD Granules group and 105 in the placebo group. BFJD Granules, as adjuvant treatment, increased the cure rate by 13.6% at the end of treatment, compared with the placebo(58.4% vs. 44.8%, P=0.02), and accelerated the median time to sputum-culture conversion(5 months vs. 11 months). The cavity closure rate of the BFJD Granules group(50.6%, 43/85) was higher than that of the placebo group(32.1%, 26/81;P=0.02) in patients who completed the treatment. At the end of the intensive treatment, according to the 36-item Short Form, the BFJD Granules significantly improved physical functioning, general health, and vitality of patients relative to the placebo group(all P<0.01). Overall, the death rates in the two groups were not significantly different;5.1%(8/156) in the BFJD Granules group and 2.6%(4/156) in the placebo group. Conclusions: Supplementing BFJD Granules with the long-course chemotherapy regimen significantly increased the cure rate and cavity closure rate, and rapidly improved QoL of patients with MDR-PTB(Registration No. ChiCTR-TRC-12002850)
