An improved radiation transmission and thermal efficiency model for solar ponds has been proposed based on both the Hull Model and Wang/Seyed-Yagoobi Model in this paper.The new model is more accurate to actual measur...An improved radiation transmission and thermal efficiency model for solar ponds has been proposed based on both the Hull Model and Wang/Seyed-Yagoobi Model in this paper.The new model is more accurate to actual measured conditions because multiple reflections and turbidity effects are included.Absorption penetration,thermal conductivity loss and thermal efficiency under different Non-Convective Zone thicknesses are numerically analyzed and thoroughly discussed.The results show thatΔT/I0 plays a critical role for the thermal efficiency of solar pond.Furthermore,it is found through calculation that there is an optimum thickness of the Non-Convective Zone.When the Non-Convective Zone thickness is less than this critical threshold,both temperature and thermal efficiency are decreased with increasing turbidity.However,when the Non-Convective Zone thickness is greater than this critical threshold,the increasing turbidity within a certain range will be beneficial to improve the thermal efficiency of solar pond.In addition,optimum Non-Convective Zone thickness is also related to the temperature,turbidity,salinity variation and bottom reflectivity.展开更多
Deep vein thrombosis(DVT)is a common complication following traumatic fracture with a 0.5%–1%annual incidence.Low molecular weight heparin(LMWH)is the most commonly used anticoagulation drug for DVT prevention,but tr...Deep vein thrombosis(DVT)is a common complication following traumatic fracture with a 0.5%–1%annual incidence.Low molecular weight heparin(LMWH)is the most commonly used anticoagulation drug for DVT prevention,but treatment with LMWH is invasive.Our aim is to compare the antithrombotic effect of dragon’s blood,an oral botanical anticoagulant medicine approved by the Chinese FDA,with LMWH in patients undergoing hip fracture surgery and to explore the molecular mechanisms of anticoagulation treatment.Our study recruited patients and divided them into LMWH and dragon’s blood treatment group.Coagulation index tests,Doppler ultrasound and mRNA sequencing were performed before and after anticoagulation therapy.There was no significant difference in postoperative DVT incidence between the two groups(23.1%versus 15.4%,P=0.694).D-dimer(D-D)and fibrinogen degradation product(FDP)showed significant reductions in both groups after anticoagulation treatments.We identified SLC4A1,PROS1,PRKAR2B and seven other genes as being differentially expressed during anticoagulation therapy in both groups.Genes correlated with coagulation indexes were also identified.Dragon’s blood and LMWH showed similar effects on DVT and produced similar gene expression changes in patients undergoing hip fracture surgery,indicating that dragon’s blood is a more convenient antithrombosis medicine(oral)than LMWH(hypodermic injection).展开更多
Fuel cell vehicles(FCVs)are facing severe heat dissipation challenges because fuel cell stacks are required to operate at a narrower temperature range and higher heat dissipation than those in the internal combustion ...Fuel cell vehicles(FCVs)are facing severe heat dissipation challenges because fuel cell stacks are required to operate at a narrower temperature range and higher heat dissipation than those in the internal combustion engine.This study conducts a numerical analysis of a tube-strip heat exchanger applied in a high-performance FCV.The typical unit cell of the tube-strip heat exchanger is selected to numerically optimize the cell-level thermal performance of the heat exchanger.Effects of structural parameters and operational conditions are investigated.The optimal structure is obtained by focusing on the heat transfer rate and fan power at the air side,where the overall heat transfer rate of heat exchanger is determined by the effectiveness number of transfer unit method and the theoretical framework of volume averaging.The results show that the heat exchanger with rectangular fins exhibits a greater heat transfer rate than those with trapezoidal and triangular fins at an inlet air velocity of 4 m/s.Compared with the fin without a louver,the heat exchangers equipped with louvers parallel and vertical with the air flow achieve heat transfer rates of 33.1 and 42.8 kW,respectively,which increase by 2.0 kW(6.4%)and 11.7 kW(37.5%)in heat transfer rate.For high-power heat dissipation,the louvered heat exchanger with a fin pitch of 2 mm shows the best thermal performance given the same fan power.展开更多
基金supported by Natural Science Foundation of Hebei Province(E2019203527)Department of Education of Hebei Province(ZD2018062).
文摘An improved radiation transmission and thermal efficiency model for solar ponds has been proposed based on both the Hull Model and Wang/Seyed-Yagoobi Model in this paper.The new model is more accurate to actual measured conditions because multiple reflections and turbidity effects are included.Absorption penetration,thermal conductivity loss and thermal efficiency under different Non-Convective Zone thicknesses are numerically analyzed and thoroughly discussed.The results show thatΔT/I0 plays a critical role for the thermal efficiency of solar pond.Furthermore,it is found through calculation that there is an optimum thickness of the Non-Convective Zone.When the Non-Convective Zone thickness is less than this critical threshold,both temperature and thermal efficiency are decreased with increasing turbidity.However,when the Non-Convective Zone thickness is greater than this critical threshold,the increasing turbidity within a certain range will be beneficial to improve the thermal efficiency of solar pond.In addition,optimum Non-Convective Zone thickness is also related to the temperature,turbidity,salinity variation and bottom reflectivity.
基金supported by the National Natural Science Foundation of China(81788101)the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences(2017-I2M-1-009).
文摘Deep vein thrombosis(DVT)is a common complication following traumatic fracture with a 0.5%–1%annual incidence.Low molecular weight heparin(LMWH)is the most commonly used anticoagulation drug for DVT prevention,but treatment with LMWH is invasive.Our aim is to compare the antithrombotic effect of dragon’s blood,an oral botanical anticoagulant medicine approved by the Chinese FDA,with LMWH in patients undergoing hip fracture surgery and to explore the molecular mechanisms of anticoagulation treatment.Our study recruited patients and divided them into LMWH and dragon’s blood treatment group.Coagulation index tests,Doppler ultrasound and mRNA sequencing were performed before and after anticoagulation therapy.There was no significant difference in postoperative DVT incidence between the two groups(23.1%versus 15.4%,P=0.694).D-dimer(D-D)and fibrinogen degradation product(FDP)showed significant reductions in both groups after anticoagulation treatments.We identified SLC4A1,PROS1,PRKAR2B and seven other genes as being differentially expressed during anticoagulation therapy in both groups.Genes correlated with coagulation indexes were also identified.Dragon’s blood and LMWH showed similar effects on DVT and produced similar gene expression changes in patients undergoing hip fracture surgery,indicating that dragon’s blood is a more convenient antithrombosis medicine(oral)than LMWH(hypodermic injection).
基金Natural Science Foundation of China(51876113)project is acknowledged.
文摘Fuel cell vehicles(FCVs)are facing severe heat dissipation challenges because fuel cell stacks are required to operate at a narrower temperature range and higher heat dissipation than those in the internal combustion engine.This study conducts a numerical analysis of a tube-strip heat exchanger applied in a high-performance FCV.The typical unit cell of the tube-strip heat exchanger is selected to numerically optimize the cell-level thermal performance of the heat exchanger.Effects of structural parameters and operational conditions are investigated.The optimal structure is obtained by focusing on the heat transfer rate and fan power at the air side,where the overall heat transfer rate of heat exchanger is determined by the effectiveness number of transfer unit method and the theoretical framework of volume averaging.The results show that the heat exchanger with rectangular fins exhibits a greater heat transfer rate than those with trapezoidal and triangular fins at an inlet air velocity of 4 m/s.Compared with the fin without a louver,the heat exchangers equipped with louvers parallel and vertical with the air flow achieve heat transfer rates of 33.1 and 42.8 kW,respectively,which increase by 2.0 kW(6.4%)and 11.7 kW(37.5%)in heat transfer rate.For high-power heat dissipation,the louvered heat exchanger with a fin pitch of 2 mm shows the best thermal performance given the same fan power.
