In this research, the centrifugal compressor of a turbocharger is investigated experimentally and numerically. Performance characteristics of the compressor were obtained experimentally by measurements of rotor speed ...In this research, the centrifugal compressor of a turbocharger is investigated experimentally and numerically. Performance characteristics of the compressor were obtained experimentally by measurements of rotor speed and flow parameters at the inlet and outlet of the compressor. Three dimensional flow field in the impeller and dif- fuser was analyzed numerically using a full Navier-Stokes program with SST turbulence model. The performance characteristics of the compressor were obtained numerically, which were then compared with the experimental results. The comparison shows good agreement. Furthermore, the effect of area ratio and tip clearance on the performance parameters and flow field was stud- ied numerically. The impeller area ratio was changed by cutting the impeller exit axial width from an initial value of 4.1 mm to a final value of 5.1 mm, resulting in an area ratio from 0.792 to 0.965. For the rotor with exit axial width of 4.6 mm, performance was investigated for tip clearance of 0.0, 0.5 and 1.0 mm. Results of this simula- tion at design point showed that the compressor pressure ratio peaked at an area ratio of 0.792 while the effi- ciency peaked at a higher value of area ratio of 0.878. Also the increment of the tip clearance from 0 to 1 mm resulted in 20 percent efficiency decrease.展开更多
Malaria is 1 mosquito-borne disease,which is most commonly caused by a parasite called Plasmodium falciparum(P.falciparum).Cerebral malaria is the most severe neurological complication presented in
Fog is a highly complex weather phenomenon influenced by numerous factors.This study investigated the impact of the Changbai Mountains’topography on the formation and development of spring fog in the Bohai Sea.From 1...Fog is a highly complex weather phenomenon influenced by numerous factors.This study investigated the impact of the Changbai Mountains’topography on the formation and development of spring fog in the Bohai Sea.From 12 to 14 May 2021,the Bohai region experienced a sea fog event.Utilizing Himawari-8 satellite data,ERA5 reanalysis dataset,land and sea station observations,the WRF model,a topography sensitivity experiment,and backward trajectory tracking,the influence of the Changbai Mountains’topography on the evolution of this sea fog event was assessed.Results indicated that the Changbai Mountains’topography significantly impacted the propagation and concentration of the sea fog through dual effects—namely,the Venturi Effect and Foehn Clearance Effect.Comparative simulations incorporating and excluding the Changbai Mountains revealed that its topography favored weak convergence(Venturi Effect)of low-level airflow over the Bohai Sea induced by a high-pressure system,promoting westward fog expansion.Additionally,the backward trajectory analysis further indicated that the Foehn Clearance Effect of the Changbai Mountains extended its influence far beyond the immediate lee side,contributing to significant changes in atmospheric conditions such as reductions in relative humidity and increases in potential temperature.The dry,warm foehn contributed to a reduction in the liquid water content,ultimately leading to the weakening or even dissipation of the sea fog in the region close to the Changbai Mountains.This study emphasizes the crucial role of the Changbai Mountains’topography in the development and evolution of fog,providing valuable insights for forecasting fog in regions with complex terrain.展开更多
Helicobacter pylori colonizes over 50%of people worldwide.Biofilm formation through penetrating gastric mucus and resistance acquired by H.pylori markedly reduces the efficacy of traditional antibiotics.The present tr...Helicobacter pylori colonizes over 50%of people worldwide.Biofilm formation through penetrating gastric mucus and resistance acquired by H.pylori markedly reduces the efficacy of traditional antibiotics.The present triple therapy and bismuth-based quadruple therapy inevitably causes intestinal flora disturbance and fails to address the excessive H.pylori-triggered inflammatory response.Herein,a mucus-permeable therapeutic platform(Cu-MOF@NF)that consists of copper-bearing metal-organic framework(Cu-MOF)loaded with nitrogen-doped carbon dots and naturally active polysaccharide fucoidan is developed.The experimental results demonstrate that Cu-MOF@NF can penetrate the mucus layer and hinder H.pylori from adhering on gastric epithelial cells of the stomach.Notably,released Cu2+can degrade the polysaccharides in the biofilm and interfere with the cyclic growing mode of"bacterioplankton↔biofilm",thereby preventing recurrent and persistent infection.Compared with traditional triple therapy,the Cu-MOF@NF not only possesses impressive antibacterial effect(even include multidrug-resistant strains),but also improves the inflammatory microenvironment without disrupting the balance of intestinal flora,providing a more efficient,safe,and antibiotic-free new approach to eradicating H.pylori.展开更多
The aim of this experimental study is to investigate the effects of hydraulic parameters on the formation of air-entraining vortices at horizontal intake structures without approach flow induced circulation. Six intak...The aim of this experimental study is to investigate the effects of hydraulic parameters on the formation of air-entraining vortices at horizontal intake structures without approach flow induced circulation. Six intake pipes of different diameters were tested in the study. The intake pipe to be tested was horizontally mounted to the front side of a large reservoir and then for a wide range of discharges experiments were conducted and critical submergences were detected with adjustable approach channel sidewalls. Empirical equations were derived for the dimensionless critical submergence as a function of the relevant dimensionless parameters. Available data is also checked for the possible scale effect. Then, these obtained equations were compared with the similar ones in the literature which showed a quite good agreement.展开更多
文摘In this research, the centrifugal compressor of a turbocharger is investigated experimentally and numerically. Performance characteristics of the compressor were obtained experimentally by measurements of rotor speed and flow parameters at the inlet and outlet of the compressor. Three dimensional flow field in the impeller and dif- fuser was analyzed numerically using a full Navier-Stokes program with SST turbulence model. The performance characteristics of the compressor were obtained numerically, which were then compared with the experimental results. The comparison shows good agreement. Furthermore, the effect of area ratio and tip clearance on the performance parameters and flow field was stud- ied numerically. The impeller area ratio was changed by cutting the impeller exit axial width from an initial value of 4.1 mm to a final value of 5.1 mm, resulting in an area ratio from 0.792 to 0.965. For the rotor with exit axial width of 4.6 mm, performance was investigated for tip clearance of 0.0, 0.5 and 1.0 mm. Results of this simula- tion at design point showed that the compressor pressure ratio peaked at an area ratio of 0.792 while the effi- ciency peaked at a higher value of area ratio of 0.878. Also the increment of the tip clearance from 0 to 1 mm resulted in 20 percent efficiency decrease.
文摘Malaria is 1 mosquito-borne disease,which is most commonly caused by a parasite called Plasmodium falciparum(P.falciparum).Cerebral malaria is the most severe neurological complication presented in
基金jointly supported by the National Natural Science Foundation of China[grant number 42205009]the Open Grants of the State Key Laboratory of Severe Weather[grant number 2024LASWB23]+1 种基金the Collaborative Innovation Project for Marine Meteorological Science and Technology in the Bohai Rim Region[grant number QYXM202315]the Research and Development Project of Hebei Provincial Meteorological Bureau[grant number 22ky26]。
文摘Fog is a highly complex weather phenomenon influenced by numerous factors.This study investigated the impact of the Changbai Mountains’topography on the formation and development of spring fog in the Bohai Sea.From 12 to 14 May 2021,the Bohai region experienced a sea fog event.Utilizing Himawari-8 satellite data,ERA5 reanalysis dataset,land and sea station observations,the WRF model,a topography sensitivity experiment,and backward trajectory tracking,the influence of the Changbai Mountains’topography on the evolution of this sea fog event was assessed.Results indicated that the Changbai Mountains’topography significantly impacted the propagation and concentration of the sea fog through dual effects—namely,the Venturi Effect and Foehn Clearance Effect.Comparative simulations incorporating and excluding the Changbai Mountains revealed that its topography favored weak convergence(Venturi Effect)of low-level airflow over the Bohai Sea induced by a high-pressure system,promoting westward fog expansion.Additionally,the backward trajectory analysis further indicated that the Foehn Clearance Effect of the Changbai Mountains extended its influence far beyond the immediate lee side,contributing to significant changes in atmospheric conditions such as reductions in relative humidity and increases in potential temperature.The dry,warm foehn contributed to a reduction in the liquid water content,ultimately leading to the weakening or even dissipation of the sea fog in the region close to the Changbai Mountains.This study emphasizes the crucial role of the Changbai Mountains’topography in the development and evolution of fog,providing valuable insights for forecasting fog in regions with complex terrain.
基金funded by the National Natural Science Foundation of China(grant no.82170580 to Y.Z.)the Key Research and Development Program of Jiangxi Province(20212BBG73004 to X.W.)the Postdoctoral Fellowship Program of CPSF(GZB20230283 to W.Z.).
文摘Helicobacter pylori colonizes over 50%of people worldwide.Biofilm formation through penetrating gastric mucus and resistance acquired by H.pylori markedly reduces the efficacy of traditional antibiotics.The present triple therapy and bismuth-based quadruple therapy inevitably causes intestinal flora disturbance and fails to address the excessive H.pylori-triggered inflammatory response.Herein,a mucus-permeable therapeutic platform(Cu-MOF@NF)that consists of copper-bearing metal-organic framework(Cu-MOF)loaded with nitrogen-doped carbon dots and naturally active polysaccharide fucoidan is developed.The experimental results demonstrate that Cu-MOF@NF can penetrate the mucus layer and hinder H.pylori from adhering on gastric epithelial cells of the stomach.Notably,released Cu2+can degrade the polysaccharides in the biofilm and interfere with the cyclic growing mode of"bacterioplankton↔biofilm",thereby preventing recurrent and persistent infection.Compared with traditional triple therapy,the Cu-MOF@NF not only possesses impressive antibacterial effect(even include multidrug-resistant strains),but also improves the inflammatory microenvironment without disrupting the balance of intestinal flora,providing a more efficient,safe,and antibiotic-free new approach to eradicating H.pylori.
基金supported by the TUBITAK (The Scientific and Technological Research Council of Turkey) (Grant No. 110M676)
文摘The aim of this experimental study is to investigate the effects of hydraulic parameters on the formation of air-entraining vortices at horizontal intake structures without approach flow induced circulation. Six intake pipes of different diameters were tested in the study. The intake pipe to be tested was horizontally mounted to the front side of a large reservoir and then for a wide range of discharges experiments were conducted and critical submergences were detected with adjustable approach channel sidewalls. Empirical equations were derived for the dimensionless critical submergence as a function of the relevant dimensionless parameters. Available data is also checked for the possible scale effect. Then, these obtained equations were compared with the similar ones in the literature which showed a quite good agreement.
