In engineering applications (Like an ocean riser), fluid flow around bluff bodies generates substantial resistance, which can jeopardize structural integrity, lifespan, and escalate resource consumption. Therefore, em...In engineering applications (Like an ocean riser), fluid flow around bluff bodies generates substantial resistance, which can jeopardize structural integrity, lifespan, and escalate resource consumption. Therefore, employing drag reduction measures becomes particularly crucial. This paper employs the immersed boundary method to investigate the impact of transversely oriented appendage plate flexibility on the drag of cylinders under different Reynolds numbers and distances. The results indicate that flexible appendage plate exerts drag reduction effects on the downstream cylinder, with this effect gradually diminishing as Reynolds numbers increase. At identical Reynolds numbers, the drag reduction effect initially increases and then decreases with distance, with the optimal drag reduction distance observed at D = 2.5. Compared to cylinders without appendage plate, the maximum drag reduction achieved is 30.551%. Addressing the drag reduction issue in cylinders holds significant importance for ensuring engineering structural integrity, enhancing engineering efficiency, and developing novel underwater towing systems.展开更多
For the quad tilt rotor aircraft, a computational fluid dynamics method based on multiple reference frames (MRF) was used to analyze the influence of aerodynamic layout parameters on the aerodynamic characteristics of...For the quad tilt rotor aircraft, a computational fluid dynamics method based on multiple reference frames (MRF) was used to analyze the influence of aerodynamic layout parameters on the aerodynamic characteristics of the quad tilt rotor aircraft. Firstly, a numerical simulation method for the interference flow field of the quad tilt rotor aircraft is established. Based on this method, the aerodynamic characteristics of isolated rotors, rotor combinations at different lateral positions on the wing, and rotor rotation directions under different inflow velocities were calculated and analyzed, in order to grasp their aerodynamic interference laws and provide reference for the design and control theory research of such aircraft.展开更多
Rapid detection and identification of Escherichia coli(E.coli)is essential to prevent its quickly spread.In this study,a novel fluorescence probe based on ZnTe quantum dots(QDs)modified by mannose(MAN)had been prepare...Rapid detection and identification of Escherichia coli(E.coli)is essential to prevent its quickly spread.In this study,a novel fluorescence probe based on ZnTe quantum dots(QDs)modified by mannose(MAN)had been prepared for the determination of E.coli.The results showed that the obtained QDs showed excellent selectivity toward E.coli,and presented a good linearity in range of 1.0×10~5~1.0×10~8 CFU/mL.The optimum fluorescence intensity for detecting E.coli was found to be at pH 7.0 with a temperature of25℃and incubation time of 20 min.Under these optimum conditions,the detection limit of E.coli was4.6×10~4 CFU/mL.The quenching was discussed to be a static quenching procedure,which was proved by the quenching efficiency of QDs decreased with the temperature increasing.展开更多
Tomato plant waste（TPW） was used as the feedstock of a batch anaerobic reactor to evaluate the effect of anaerobic digestion on Ralstonia solanacearum and Phytophthora capsici survival. Batch experiments were carrie...Tomato plant waste（TPW） was used as the feedstock of a batch anaerobic reactor to evaluate the effect of anaerobic digestion on Ralstonia solanacearum and Phytophthora capsici survival. Batch experiments were carried out for TS（total solid） concentrations of 2%, 4% and 6% respectively, at mesophilic（37 ± 1°C） and room（20–25°C） temperatures. Results showed that higher digestion performance was achieved under mesophilic digestion temperature and lower TS concentration conditions. The biogas production ranged from 71 to 416 L/kg VS（volatile solids）. The inactivation of anaerobic digestion tended to increase as digestion performance improved. The maximum log copies reduction of R. solanacearum and P. capsici detected by quantitative PCR（polymerase chain reaction） were 3.80 and 4.08 respectively in reactors with 4% TS concentration at mesophilic temperatures. However, both in mesophilic and room temperature conditions, the lowest reduction of R. solanacearum was found in the reactors with 6% TS concentration, which possessed the highest VFA（volatile fatty acid） concentration. These findings indicated that simple accumulation of VFAs failed to restrain R. solanacearum effectively, although the VFAs were considered poisonous. P. capsici was nearly completely dead under all conditions. Based on the digestion performance and the pathogen survival rate, a model was established to evaluate the digestate biosafety.展开更多
文摘In engineering applications (Like an ocean riser), fluid flow around bluff bodies generates substantial resistance, which can jeopardize structural integrity, lifespan, and escalate resource consumption. Therefore, employing drag reduction measures becomes particularly crucial. This paper employs the immersed boundary method to investigate the impact of transversely oriented appendage plate flexibility on the drag of cylinders under different Reynolds numbers and distances. The results indicate that flexible appendage plate exerts drag reduction effects on the downstream cylinder, with this effect gradually diminishing as Reynolds numbers increase. At identical Reynolds numbers, the drag reduction effect initially increases and then decreases with distance, with the optimal drag reduction distance observed at D = 2.5. Compared to cylinders without appendage plate, the maximum drag reduction achieved is 30.551%. Addressing the drag reduction issue in cylinders holds significant importance for ensuring engineering structural integrity, enhancing engineering efficiency, and developing novel underwater towing systems.
文摘For the quad tilt rotor aircraft, a computational fluid dynamics method based on multiple reference frames (MRF) was used to analyze the influence of aerodynamic layout parameters on the aerodynamic characteristics of the quad tilt rotor aircraft. Firstly, a numerical simulation method for the interference flow field of the quad tilt rotor aircraft is established. Based on this method, the aerodynamic characteristics of isolated rotors, rotor combinations at different lateral positions on the wing, and rotor rotation directions under different inflow velocities were calculated and analyzed, in order to grasp their aerodynamic interference laws and provide reference for the design and control theory research of such aircraft.
基金the grants from National Natural Science Foundation of Guangdong Province(Nos.2017A030310666 and 2018A030307003)Guangdong Medical University Nanhai Marine Biomedical Resources R&D Public Service Platform Open Fund Project(Nos.2HC18013 and 2HC18016)+4 种基金"Group-type"Special Support Project for Education Talents in Universities(No.4SG19045G)Foundation of Young Innovative Talents in Guangdong Province Colleges(No.2018KQNCX091)Undergraduate Science&Technology Innovation Foundation of Guangdong Province(Nos.201810571046 and 201810571073)Medical Science and Technology Development Foundation of Guangdong Province(No.A2016355)The Opening Project of State Key Laboratory of Polymer Materials Engineering of Sichuan University(No.sklpme2018-4-23)。
文摘Rapid detection and identification of Escherichia coli(E.coli)is essential to prevent its quickly spread.In this study,a novel fluorescence probe based on ZnTe quantum dots(QDs)modified by mannose(MAN)had been prepared for the determination of E.coli.The results showed that the obtained QDs showed excellent selectivity toward E.coli,and presented a good linearity in range of 1.0×10~5~1.0×10~8 CFU/mL.The optimum fluorescence intensity for detecting E.coli was found to be at pH 7.0 with a temperature of25℃and incubation time of 20 min.Under these optimum conditions,the detection limit of E.coli was4.6×10~4 CFU/mL.The quenching was discussed to be a static quenching procedure,which was proved by the quenching efficiency of QDs decreased with the temperature increasing.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest (No. 201503135-17)
文摘Tomato plant waste（TPW） was used as the feedstock of a batch anaerobic reactor to evaluate the effect of anaerobic digestion on Ralstonia solanacearum and Phytophthora capsici survival. Batch experiments were carried out for TS（total solid） concentrations of 2%, 4% and 6% respectively, at mesophilic（37 ± 1°C） and room（20–25°C） temperatures. Results showed that higher digestion performance was achieved under mesophilic digestion temperature and lower TS concentration conditions. The biogas production ranged from 71 to 416 L/kg VS（volatile solids）. The inactivation of anaerobic digestion tended to increase as digestion performance improved. The maximum log copies reduction of R. solanacearum and P. capsici detected by quantitative PCR（polymerase chain reaction） were 3.80 and 4.08 respectively in reactors with 4% TS concentration at mesophilic temperatures. However, both in mesophilic and room temperature conditions, the lowest reduction of R. solanacearum was found in the reactors with 6% TS concentration, which possessed the highest VFA（volatile fatty acid） concentration. These findings indicated that simple accumulation of VFAs failed to restrain R. solanacearum effectively, although the VFAs were considered poisonous. P. capsici was nearly completely dead under all conditions. Based on the digestion performance and the pathogen survival rate, a model was established to evaluate the digestate biosafety.
