We investigated the solid–liquid suspension characteristics in the tank with a liquid height/tank diameter ratio of 1.5 stirred by a novel long-short blades(LSB) impeller by the Euler granular flow model coupled with...We investigated the solid–liquid suspension characteristics in the tank with a liquid height/tank diameter ratio of 1.5 stirred by a novel long-short blades(LSB) impeller by the Euler granular flow model coupled with the standard k–ε turbulence model. After validation of the local solid holdup by experiments,numerical predictions have been successfully used to explain the influences of impeller rotating speed,particle density, particle size, liquid viscosity and initial solid loading on the solid suspension behavior,i.e. smaller particles with lower density are more likely to be suspended evenly in the liquid with higher liquid viscosity. At a low impeller rotating speed(N), increase in N leads to an obvious improvement in the solid distribution homogeneity. Moreover, the proposed LSB impeller has obvious advantages in the uniform distribution of the solid particles compared with single Rushton turbine(RT), dual RT impellers or CBY hydrofoil impeller under the same power consumption.展开更多
The low power and narrow speed range remain bottlenecks that constrain the application of small-scale wind energy harvesting.This paper proposes a simple,lowcost,and reliable method to address these critical issues.A ...The low power and narrow speed range remain bottlenecks that constrain the application of small-scale wind energy harvesting.This paper proposes a simple,lowcost,and reliable method to address these critical issues.A galloping energy harvester with the cooperative mode of vibration and collision(GEH-VC)is presented.A pair of curved boundaries attached with functional materials are introduced,which not only improve the performance of the vibration energy harvesting system,but also convert more mechanical energy into electrical energy during collision.The beam deforms and the piezoelectric energy harvester(PEH)generates electricity during the flow-induced vibration.In addition,the beam contacts and separates from the boundaries,and the triboelectric nanogenerator(TENG)generates electricity during the collision.In order to reduce the influence of the boundaries on the aerodynamic performance and the feasibility of increasing the working area of the TENG,a vertical structure is designed.When the wind speed is high,the curved boundaries maintain a stable amplitude of the vibration system and increase the frequency of the vibration system,thereby avoiding damage to the piezoelectric sheet and improving the electromechanical conversion efficiency,and the TENG works with the PEH to generate electricity.Since the boundaries can protect the PEH at high wind speeds,its stiffness can be designed to be low to start working at low wind speeds.The electromechanical coupling dynamic model is established according to the GEH-VC operating principle and is verified experimentally.The results show that the GEH-VC has a wide range of operating wind speeds,and the average power can be increased by 180%compared with the traditional galloping PEH.The GEH-VC prototype is demonstrated to power a commercial temperature sensor.This study provides a novel perspective on the design of hybrid electromechanical conversion mechanisms,that is,to combine and collaborate based on their respective characteristics.展开更多
A congenital coronary artery fistula(CCAF)combined with giant coronary aneurysm(CAA)is a rare congenital cardiac abnormality.We reported an 8-year-old patient who underwent transcatheter closure of both inlet and outl...A congenital coronary artery fistula(CCAF)combined with giant coronary aneurysm(CAA)is a rare congenital cardiac abnormality.We reported an 8-year-old patient who underwent transcatheter closure of both inlet and outlet of a proximal left coronary artery(LCA)-to-left ventricular(LV)fistula with CAA of 41 mm×28 mm in diameter,during which acute occlusion of left anterior descending coronary artery(LAD)occurred immediately after device implantation at the inlet of fistula.We managed to prevent the patient from major adverse cardiac events by conservative therapy with dual antiplatelet agents instead of surgical removal of the device.The patient recovered well and had been follow-up for 2 years with no late complications reported.展开更多
Background:Limited data are available regarding intermediate and long-term outcomes of transcatheter closure(TCC)of coronary cameral fistulas(CCFs)in the pediatric patients.Methods:All pediatric patients diagnosed wit...Background:Limited data are available regarding intermediate and long-term outcomes of transcatheter closure(TCC)of coronary cameral fistulas(CCFs)in the pediatric patients.Methods:All pediatric patients diagnosed with CCFs who were scheduled to undergo TCC between 2005 and 2019 were retrospectively enrolled in the study.Results:A total of 66 patients(median age:3.93 years,median weight:15 kg)underwent attempted TCC of CCFs.Immediate successful device implantation was achieved in 62 patients,and immediate complete occlusion was achieved in 44 patients(44/62%,71.0%).The closure procedure was waived in 2 patients due to anatomical factors.A total of 6 periprocedural complications occurred in 5 patients,including acute myocardial infarction(n=3),procedure-related death(n=1),device embolization(n=1),and rupture of tricuspid chordae tendineae(n=1).The acute procedural success rate was 89.4%(59/66),while the acute complication rate was 9.1%(6/66).Follow-up data were collected for 58(93.5%)out of 62 patients at a median of 9.3 years(range:3.0–15.7 years).10 adverse events occurred in 9 patients,including 5 follow-up complications(1 aortic valve perforation,1 coronary thrombosis,1 progressive aneurysmal dilation after reintervention,and 2 cases of new-onset tricuspid valve prolapse with significant regurgitation),and 5 closure failure with large residual shunts.The intermediate and long-term adverse event rate was 17.2%(10/58).The anatomical features associated with both acute and follow-up adverse events were large CCFs(p=0.005),and giant coronary artery aneurysms(CAAs)(p=0.029).Conclusions:TCC of CCFs in infants and children appears to be effective and is associated with a relatively low complication rate.Large CCFs and giant CAAs represent a higher risk of both acute and intermediate and long-term adverse events after closure.展开更多
Efficient regulation of thermal radiation is an effective way to conserve energy consumption of buildings.Because windows are the least energy-efficient part of buildings,their thermal radiation regulation is highly d...Efficient regulation of thermal radiation is an effective way to conserve energy consumption of buildings.Because windows are the least energy-efficient part of buildings,their thermal radiation regulation is highly demanded,especially in the changing environment,but is still a challenge.Here,by employing a kirigami structure,we design a variable-angle thermal reflector as a transparent envelope of windows for their thermal radiation modulation.The envelope can be easily switched between heating and cooling modes by loading different pre-stresses,which endow the envelope windows with the ability of temperature regulation,and the interior temperature of a building model can be reduced by~3.3°C under cooling mode and increased by~3.9°C under heating mode in the outdoor test.The improved thermal management of windows by the adaptive envelope provides an extra heating,ventilation,and air-conditioning energy savings percentage of 13%to 29%per year for buildings located in different climate zones around the world,making the kirigami envelope windows a promising way for energy-saving utilization.展开更多
基金the financial support from the National Natural Science Foundation of China (22078058)Open Research Fund Program of CAS Key Laboratory of Energy Regulation Materials (ORFP2020–02)
文摘We investigated the solid–liquid suspension characteristics in the tank with a liquid height/tank diameter ratio of 1.5 stirred by a novel long-short blades(LSB) impeller by the Euler granular flow model coupled with the standard k–ε turbulence model. After validation of the local solid holdup by experiments,numerical predictions have been successfully used to explain the influences of impeller rotating speed,particle density, particle size, liquid viscosity and initial solid loading on the solid suspension behavior,i.e. smaller particles with lower density are more likely to be suspended evenly in the liquid with higher liquid viscosity. At a low impeller rotating speed(N), increase in N leads to an obvious improvement in the solid distribution homogeneity. Moreover, the proposed LSB impeller has obvious advantages in the uniform distribution of the solid particles compared with single Rushton turbine(RT), dual RT impellers or CBY hydrofoil impeller under the same power consumption.
基金the National Natural Science Foundation of China (Nos. 11802091and 12172127)the Hunan Province Science and Technology Innovation Program of China(Nos. 2020JJ3019 and 2019RS2044)the Scientific Researchof Hunan Provincial Department of Education of China (No. 21A0463)
文摘The low power and narrow speed range remain bottlenecks that constrain the application of small-scale wind energy harvesting.This paper proposes a simple,lowcost,and reliable method to address these critical issues.A galloping energy harvester with the cooperative mode of vibration and collision(GEH-VC)is presented.A pair of curved boundaries attached with functional materials are introduced,which not only improve the performance of the vibration energy harvesting system,but also convert more mechanical energy into electrical energy during collision.The beam deforms and the piezoelectric energy harvester(PEH)generates electricity during the flow-induced vibration.In addition,the beam contacts and separates from the boundaries,and the triboelectric nanogenerator(TENG)generates electricity during the collision.In order to reduce the influence of the boundaries on the aerodynamic performance and the feasibility of increasing the working area of the TENG,a vertical structure is designed.When the wind speed is high,the curved boundaries maintain a stable amplitude of the vibration system and increase the frequency of the vibration system,thereby avoiding damage to the piezoelectric sheet and improving the electromechanical conversion efficiency,and the TENG works with the PEH to generate electricity.Since the boundaries can protect the PEH at high wind speeds,its stiffness can be designed to be low to start working at low wind speeds.The electromechanical coupling dynamic model is established according to the GEH-VC operating principle and is verified experimentally.The results show that the GEH-VC has a wide range of operating wind speeds,and the average power can be increased by 180%compared with the traditional galloping PEH.The GEH-VC prototype is demonstrated to power a commercial temperature sensor.This study provides a novel perspective on the design of hybrid electromechanical conversion mechanisms,that is,to combine and collaborate based on their respective characteristics.
基金This work was supported by Guangdong Provincial Clinical Research Center for Cardiovascular Disease[Grant No.2020B1111170011]National Key R&D Program of China[Grant No.2016YFC1100305]Shenzhen Sanming Medical Project of China[Grant No.SZSM201612057].
文摘A congenital coronary artery fistula(CCAF)combined with giant coronary aneurysm(CAA)is a rare congenital cardiac abnormality.We reported an 8-year-old patient who underwent transcatheter closure of both inlet and outlet of a proximal left coronary artery(LCA)-to-left ventricular(LV)fistula with CAA of 41 mm×28 mm in diameter,during which acute occlusion of left anterior descending coronary artery(LAD)occurred immediately after device implantation at the inlet of fistula.We managed to prevent the patient from major adverse cardiac events by conservative therapy with dual antiplatelet agents instead of surgical removal of the device.The patient recovered well and had been follow-up for 2 years with no late complications reported.
基金Guangdong Provincial Clinical Research Center for Cardiovascular Disease[Grant No.2020B1111170011]Guangzhou Science and Technology Project[Grant No.2023A04J0485]National Key R&D Program of China[Grant No.2016YFC1100305].
文摘Background:Limited data are available regarding intermediate and long-term outcomes of transcatheter closure(TCC)of coronary cameral fistulas(CCFs)in the pediatric patients.Methods:All pediatric patients diagnosed with CCFs who were scheduled to undergo TCC between 2005 and 2019 were retrospectively enrolled in the study.Results:A total of 66 patients(median age:3.93 years,median weight:15 kg)underwent attempted TCC of CCFs.Immediate successful device implantation was achieved in 62 patients,and immediate complete occlusion was achieved in 44 patients(44/62%,71.0%).The closure procedure was waived in 2 patients due to anatomical factors.A total of 6 periprocedural complications occurred in 5 patients,including acute myocardial infarction(n=3),procedure-related death(n=1),device embolization(n=1),and rupture of tricuspid chordae tendineae(n=1).The acute procedural success rate was 89.4%(59/66),while the acute complication rate was 9.1%(6/66).Follow-up data were collected for 58(93.5%)out of 62 patients at a median of 9.3 years(range:3.0–15.7 years).10 adverse events occurred in 9 patients,including 5 follow-up complications(1 aortic valve perforation,1 coronary thrombosis,1 progressive aneurysmal dilation after reintervention,and 2 cases of new-onset tricuspid valve prolapse with significant regurgitation),and 5 closure failure with large residual shunts.The intermediate and long-term adverse event rate was 17.2%(10/58).The anatomical features associated with both acute and follow-up adverse events were large CCFs(p=0.005),and giant coronary artery aneurysms(CAAs)(p=0.029).Conclusions:TCC of CCFs in infants and children appears to be effective and is associated with a relatively low complication rate.Large CCFs and giant CAAs represent a higher risk of both acute and intermediate and long-term adverse events after closure.
基金The authors acknowledge financial support from the National Key R&D Program of China(grant no.2018YFA0209200)Key R&D Program of Hubei Province(2022BAA028)+1 种基金National Natural Science Foundation of China(62274071 and 61674064)Shenzhen Science and Technology Program(JCYJ20220530160808018).
文摘Efficient regulation of thermal radiation is an effective way to conserve energy consumption of buildings.Because windows are the least energy-efficient part of buildings,their thermal radiation regulation is highly demanded,especially in the changing environment,but is still a challenge.Here,by employing a kirigami structure,we design a variable-angle thermal reflector as a transparent envelope of windows for their thermal radiation modulation.The envelope can be easily switched between heating and cooling modes by loading different pre-stresses,which endow the envelope windows with the ability of temperature regulation,and the interior temperature of a building model can be reduced by~3.3°C under cooling mode and increased by~3.9°C under heating mode in the outdoor test.The improved thermal management of windows by the adaptive envelope provides an extra heating,ventilation,and air-conditioning energy savings percentage of 13%to 29%per year for buildings located in different climate zones around the world,making the kirigami envelope windows a promising way for energy-saving utilization.
