As an efficient passive anti-icing method,the superhydrophobic surface can reduce icing process on metals in low temperatures.However,the usual organic low-surface-energy decorations are often prone to age especially ...As an efficient passive anti-icing method,the superhydrophobic surface can reduce icing process on metals in low temperatures.However,the usual organic low-surface-energy decorations are often prone to age especially in harsh environments,leading to a decrease or complete failure of the anti-icing performance.Here,we adopt a fabrication method of femtosecond laser element-doping microstructuring to achieve inor-ganic superhydrophobic aluminum alloys surfaces through simultaneously modifying the surface profile and compositions of aluminum alloys.The obtained bionic anthill tribe structure with the low thermal conductiv-ity,exhibits the superior delayed freezing time(803.3 s)and the low ice adhesion(16μN)in comparison to the fluorosilane modified and bare Al surfaces.Moreover,such an inherently superhydrophobic metal sur-face also shows the exceptional environmental durability in anti-icing performance,which confirms the ef-fectiveness of our superhydrophobic surface without the need for organic coatings.展开更多
De-icing technology has become an increasingly important subject in numerous applications in recent years.However,the direct numerical modeling and simulation the physical process of thermomechanical deicing is limite...De-icing technology has become an increasingly important subject in numerous applications in recent years.However,the direct numerical modeling and simulation the physical process of thermomechanical deicing is limited.This work is focusing on developing a numerical model and tool to direct simulate the de-icing process in the framework of the coupled thermo-mechanical peridynamics theory.Here,we adopted the fully coupled thermo-mechanical bond-based peridynamics(TM-BB-PD)method for modeling and simulation of de-icing.Within the framework of TM-BB-PD,the ice constitutive model is established by considering the influence of the temperature difference between two material points,and a modified failure criteria is proposed,which takes into account temperature effect to predict the damage of quasi-brittle ice material.Moreover,thermal boundary condition is used to simulate the thermal load in the de-icing process.By comparing with the experimental results and the previous reported finite element modeling,our numerical model shows good agreement with the previous predictions.Based on the numerical results,we find that the developed method can not only predict crack initiation and propagation in the ice,but also predict the temperature distribution and heat conduction during the de-icing process.Furthermore,the influence of the temperature for the ice crack growth pattern is discussed accordingly.In conclusion,the coupled thermal-mechanical peridynamics formulation with modified failure criterion is capable of providing a modeling tool for engineering applications of de-icing technology.展开更多
The anti——icing and de·-icing methods of insulator strings are still under laboratory studies while many technologies are applied in operation to overhead conductors.The anti—icing method using semiconducting ...The anti——icing and de·-icing methods of insulator strings are still under laboratory studies while many technologies are applied in operation to overhead conductors.The anti—icing method using semiconducting silicone rubber coating applied to the bottom side of the insulators could get good results in a climate chamber.However,the resistance of the coating is an important factor influencing the anti—icing performance of the coated insulators.Thus the coating resistance should be determined.展开更多
Fetal liver tissues obtained from 28 human fetuses with gestation age from 3 to 6 months and fetal bone marrow from 35 human fetuses from 3 to 7 months were observed by immunochemical staining with anti-platelet GPⅡ ...Fetal liver tissues obtained from 28 human fetuses with gestation age from 3 to 6 months and fetal bone marrow from 35 human fetuses from 3 to 7 months were observed by immunochemical staining with anti-platelet GPⅡ b / Ⅲa monoclonal antibody and ABC technique. In the fetal liver, megakaryocytes were wholly located among growing fetal liver cells and near foci of hemopoiesis. Some megakaryocytes in the fetal liver were small7890- lymphoid-like megakaryocytes. The size of megakaryocytes both in the fetal liver (14.79 ± 4.52μm) and in the fetal bone marrow (16.08±7.39 μm) was small, which did not vary significantly over the gestation age ranging from 3 to 6 or 7 months. However, the maturation stage of megakaryocytes in the fetal liver shifted to more mature stage with the advancement of gestation, although the maturation stage of megakaryocytes in the fetal bone marrow did not change with the advancement of gestation from 4 to 7 months, the megakaryocyte in the fetal bone marrow was less mature展开更多
文摘As an efficient passive anti-icing method,the superhydrophobic surface can reduce icing process on metals in low temperatures.However,the usual organic low-surface-energy decorations are often prone to age especially in harsh environments,leading to a decrease or complete failure of the anti-icing performance.Here,we adopt a fabrication method of femtosecond laser element-doping microstructuring to achieve inor-ganic superhydrophobic aluminum alloys surfaces through simultaneously modifying the surface profile and compositions of aluminum alloys.The obtained bionic anthill tribe structure with the low thermal conductiv-ity,exhibits the superior delayed freezing time(803.3 s)and the low ice adhesion(16μN)in comparison to the fluorosilane modified and bare Al surfaces.Moreover,such an inherently superhydrophobic metal sur-face also shows the exceptional environmental durability in anti-icing performance,which confirms the ef-fectiveness of our superhydrophobic surface without the need for organic coatings.
基金the University of California at Berkeley.Ms.Y.Song gratefully acknowledges the financial support from the Chinese Scholar Council(CSC Grant No.201706680094).
文摘De-icing technology has become an increasingly important subject in numerous applications in recent years.However,the direct numerical modeling and simulation the physical process of thermomechanical deicing is limited.This work is focusing on developing a numerical model and tool to direct simulate the de-icing process in the framework of the coupled thermo-mechanical peridynamics theory.Here,we adopted the fully coupled thermo-mechanical bond-based peridynamics(TM-BB-PD)method for modeling and simulation of de-icing.Within the framework of TM-BB-PD,the ice constitutive model is established by considering the influence of the temperature difference between two material points,and a modified failure criteria is proposed,which takes into account temperature effect to predict the damage of quasi-brittle ice material.Moreover,thermal boundary condition is used to simulate the thermal load in the de-icing process.By comparing with the experimental results and the previous reported finite element modeling,our numerical model shows good agreement with the previous predictions.Based on the numerical results,we find that the developed method can not only predict crack initiation and propagation in the ice,but also predict the temperature distribution and heat conduction during the de-icing process.Furthermore,the influence of the temperature for the ice crack growth pattern is discussed accordingly.In conclusion,the coupled thermal-mechanical peridynamics formulation with modified failure criterion is capable of providing a modeling tool for engineering applications of de-icing technology.
文摘The anti——icing and de·-icing methods of insulator strings are still under laboratory studies while many technologies are applied in operation to overhead conductors.The anti—icing method using semiconducting silicone rubber coating applied to the bottom side of the insulators could get good results in a climate chamber.However,the resistance of the coating is an important factor influencing the anti—icing performance of the coated insulators.Thus the coating resistance should be determined.
文摘Fetal liver tissues obtained from 28 human fetuses with gestation age from 3 to 6 months and fetal bone marrow from 35 human fetuses from 3 to 7 months were observed by immunochemical staining with anti-platelet GPⅡ b / Ⅲa monoclonal antibody and ABC technique. In the fetal liver, megakaryocytes were wholly located among growing fetal liver cells and near foci of hemopoiesis. Some megakaryocytes in the fetal liver were small7890- lymphoid-like megakaryocytes. The size of megakaryocytes both in the fetal liver (14.79 ± 4.52μm) and in the fetal bone marrow (16.08±7.39 μm) was small, which did not vary significantly over the gestation age ranging from 3 to 6 or 7 months. However, the maturation stage of megakaryocytes in the fetal liver shifted to more mature stage with the advancement of gestation, although the maturation stage of megakaryocytes in the fetal bone marrow did not change with the advancement of gestation from 4 to 7 months, the megakaryocyte in the fetal bone marrow was less mature
