This study investigates the aerodynamic performance of the NACA 633-421 airfoil and the effectiveness and feasibility of intermittent disturbance flow control methods on laminar separation bubbles(LSBs).It is found th...This study investigates the aerodynamic performance of the NACA 633-421 airfoil and the effectiveness and feasibility of intermittent disturbance flow control methods on laminar separation bubbles(LSBs).It is found that the average velocity and influence range of the synthetic jet actuator increase with the increasing of driving frequency and driving amplitude.LSB occurs at Re=1.0×10^(5),and ruptures atα=6°.But with intermittent disturbance control,the stall angle of attack(AoA)increases while significantly reducing drag.Research shows that although certain disturbance cannot fully recover from LSB stall,decreasing driving amplitude partially restores wing aerodynamic performance,more effectively than increasing driving amplitude.展开更多
Commercial3D reticular nickel foam and its composite structure were investigated on the sound absorption at200-2000Hz.The absorption performance of foam plates1?5layers(1-layer thickness:2.3mm;porosity:89%;average por...Commercial3D reticular nickel foam and its composite structure were investigated on the sound absorption at200-2000Hz.The absorption performance of foam plates1?5layers(1-layer thickness:2.3mm;porosity:89%;average pore-diameter:0.57mm)was found to be poor,and could be improved by adding backed cavum or front perforated thin sheet.The absorption coefficient could reach about0.4at1000-1600Hz for the composite structure of5-layer foam with a backed5mm-thick cavum,and even0.68at about1000Hz for that of2-layer foam with the same cavum and a perforated plate closely in front of the foam.展开更多
The study was conducted to determine the viability of producing organic onion under the fully converted area of Ramon Magsaysay Center for Agricultural Resources and Environment Studies （RMC-ARES）, Central Luzon Sta...The study was conducted to determine the viability of producing organic onion under the fully converted area of Ramon Magsaysay Center for Agricultural Resources and Environment Studies （RMC-ARES）, Central Luzon State University, Philippines. Specifically, the study aimed to establish the fi＇equency of organic fertilizer and Trichoderma spp. application, employing split application, and determine the yield performance of red onion （bulb type）. The research was conducted for two consecutive dry seasons （2014 and 2015）. Red Creole variety was used with the following treatments： T1--organic fertilizer alone （8 ton/ha） at planting; T2--organic fertilizer （8 ton/ha） applied twice （at basal and 30 d after transplanting （DAT））; T3---organic fertilizer （8 ton/ha） applied twice （at basal and 30 DAT） ＋ Trichoderma spp. at the rate of 526 kg/ha applied at planting; T4----organie fertilizer at 8 ton/ha rate ＋ Trichoderma spp. at the rate of 526 kg/ha, both applied twice （at planting and 30 DAT）; T5--organic fertilizer at 8 ton/ha rate applied twice （at planting and 30 DAT） ＋ Trichoderma spp. at the rate of 526 kg/ha applied thrice （at planting, 30 DAT and during bulb formation）. Results of the study showed that application of the recommended rate of organic fertilizer twice （at planting and 30 DAT） ＋ three times application of Trichoderma spp. （at planting, 30 DAT and during bulb formation） consistently produced bigger bulb during the first and second trial of the study, compared to other treatments evaluated. Consequently, higher marketable yield was produced with 15.33 ton/ha during the first trial and 14.50 ton/ha on the second trial.展开更多
The development of low-frequency ultrasound imaging technology and the improvement of ultrasound contrast agent production technology mean that they play an increasingly important role in tumor therapy. The interactio...The development of low-frequency ultrasound imaging technology and the improvement of ultrasound contrast agent production technology mean that they play an increasingly important role in tumor therapy. The interaction between ultrasound and microbubbles and their biological effects can transfer and release microbubbles carrying genes and drugs to target tissues, mediate the apoptosis of tumor cells, and block the embolization of tumor microvasculature. With the optimization of ultrasound parameters, the development of targeted microbubbles, and the emergence of various composite probes with both diagnostic and therapeutic functions, low-frequency ultrasound combined with microbubble contrast agents will bring new hope for clinical tumor treatment.展开更多
LES (Large-Eddy Simulation) computations were preformed to investigate the mechanisms of a kind of spanwisegroove for the passive control of laminar separation bubble on the suction surface of a low-speed highly loade...LES (Large-Eddy Simulation) computations were preformed to investigate the mechanisms of a kind of spanwisegroove for the passive control of laminar separation bubble on the suction surface of a low-speed highly loadedlow-pressure turbine blade at Re = 50,000 (Reynolds number, based on inlet velocity and axial chord length).Compared with the smooth suction surface, the numerical results indicate that: (1) the groove is effective toshorten and thin the separation bubble, which contributes the flow loss reduction on the groove surface, by thinningthe boundary layer behind the groove and promoting earlier transition inception in the separation bubble; (2)upstream movement of the transition inception location on the grooved surface is suggested being the result of thelower frequency at which the highest amplification rate of instability waves occurs, and the larger initial amplitudeof the disturbance at the most unstable frequency before transition; and (3) the viscous instability mode ispromoted on the grooved surface, due to the thinning of the boundary layer behind the groove.展开更多
文摘This study investigates the aerodynamic performance of the NACA 633-421 airfoil and the effectiveness and feasibility of intermittent disturbance flow control methods on laminar separation bubbles(LSBs).It is found that the average velocity and influence range of the synthetic jet actuator increase with the increasing of driving frequency and driving amplitude.LSB occurs at Re=1.0×10^(5),and ruptures atα=6°.But with intermittent disturbance control,the stall angle of attack(AoA)increases while significantly reducing drag.Research shows that although certain disturbance cannot fully recover from LSB stall,decreasing driving amplitude partially restores wing aerodynamic performance,more effectively than increasing driving amplitude.
基金Project (C16) supported by the Testing Foundation of Beijing Normal University,China
文摘Commercial3D reticular nickel foam and its composite structure were investigated on the sound absorption at200-2000Hz.The absorption performance of foam plates1?5layers(1-layer thickness:2.3mm;porosity:89%;average pore-diameter:0.57mm)was found to be poor,and could be improved by adding backed cavum or front perforated thin sheet.The absorption coefficient could reach about0.4at1000-1600Hz for the composite structure of5-layer foam with a backed5mm-thick cavum,and even0.68at about1000Hz for that of2-layer foam with the same cavum and a perforated plate closely in front of the foam.
文摘The study was conducted to determine the viability of producing organic onion under the fully converted area of Ramon Magsaysay Center for Agricultural Resources and Environment Studies （RMC-ARES）, Central Luzon State University, Philippines. Specifically, the study aimed to establish the fi＇equency of organic fertilizer and Trichoderma spp. application, employing split application, and determine the yield performance of red onion （bulb type）. The research was conducted for two consecutive dry seasons （2014 and 2015）. Red Creole variety was used with the following treatments： T1--organic fertilizer alone （8 ton/ha） at planting; T2--organic fertilizer （8 ton/ha） applied twice （at basal and 30 d after transplanting （DAT））; T3---organic fertilizer （8 ton/ha） applied twice （at basal and 30 DAT） ＋ Trichoderma spp. at the rate of 526 kg/ha applied at planting; T4----organie fertilizer at 8 ton/ha rate ＋ Trichoderma spp. at the rate of 526 kg/ha, both applied twice （at planting and 30 DAT）; T5--organic fertilizer at 8 ton/ha rate applied twice （at planting and 30 DAT） ＋ Trichoderma spp. at the rate of 526 kg/ha applied thrice （at planting, 30 DAT and during bulb formation）. Results of the study showed that application of the recommended rate of organic fertilizer twice （at planting and 30 DAT） ＋ three times application of Trichoderma spp. （at planting, 30 DAT and during bulb formation） consistently produced bigger bulb during the first and second trial of the study, compared to other treatments evaluated. Consequently, higher marketable yield was produced with 15.33 ton/ha during the first trial and 14.50 ton/ha on the second trial.
基金Project supported by the Health and Family Planning Commission of Zhejiang Province(No.2017KY676),China
文摘The development of low-frequency ultrasound imaging technology and the improvement of ultrasound contrast agent production technology mean that they play an increasingly important role in tumor therapy. The interaction between ultrasound and microbubbles and their biological effects can transfer and release microbubbles carrying genes and drugs to target tissues, mediate the apoptosis of tumor cells, and block the embolization of tumor microvasculature. With the optimization of ultrasound parameters, the development of targeted microbubbles, and the emergence of various composite probes with both diagnostic and therapeutic functions, low-frequency ultrasound combined with microbubble contrast agents will bring new hope for clinical tumor treatment.
文摘LES (Large-Eddy Simulation) computations were preformed to investigate the mechanisms of a kind of spanwisegroove for the passive control of laminar separation bubble on the suction surface of a low-speed highly loadedlow-pressure turbine blade at Re = 50,000 (Reynolds number, based on inlet velocity and axial chord length).Compared with the smooth suction surface, the numerical results indicate that: (1) the groove is effective toshorten and thin the separation bubble, which contributes the flow loss reduction on the groove surface, by thinningthe boundary layer behind the groove and promoting earlier transition inception in the separation bubble; (2)upstream movement of the transition inception location on the grooved surface is suggested being the result of thelower frequency at which the highest amplification rate of instability waves occurs, and the larger initial amplitudeof the disturbance at the most unstable frequency before transition; and (3) the viscous instability mode ispromoted on the grooved surface, due to the thinning of the boundary layer behind the groove.
