With the springing up of new technologies and materials in aircraft,the thermal management of aircraft is facing the dilemma of heat load increase and effective heat sink decrease.Hence the limiting factor of certain ...With the springing up of new technologies and materials in aircraft,the thermal management of aircraft is facing the dilemma of heat load increase and effective heat sink decrease.Hence the limiting factor of certain advanced aircraft is gradually changing from fuel to heat,and increasing emphasis on addressing the issue of aircraft environmental control should be placed.To reduce the energy consumption and improve the endurance of aircraft systems,this study reviews the development of aircraft environmental control technologies and analyzes the solutions in a human-machine cooperative manner.The comfortable temperature and humidity for personnel is generally between 18∼29℃and 20%∼30%respectively,and the normal working temperature of equipment is usually 15∼90℃.Using multiple indexes to evaluate the personnel comfort,equipment cooling and system energy consumption levels of existing aircraft environmental control technologies,it is found that the environmental needs of personnel and equipment cabin can be basically met with significant progress made in various technologies,e.g.equipment cooling,dehumidification and humidification,anti-freeze defrost and etc.Whereas there is rare research on the energy cascading utilization technology for human-machine synergistic environment and there exists challenges in applying the environmental control technology for cooling high-powered equipment to the personnel cabin.Finally,it is proposed that the future aircraft environmental control should develop cascading energy utilization,efficient cooling and shared control technologies,to take advantages of the humanmachine collaborative regulation and cope with the challenges caused by transient thermal load impacts on the system.展开更多
Based on the results of seven corroded reinforced concrete(RC)shear walls with a high shear-span ratio under an artificial climatic environment(ACE)that were subjected to pseudo-static cyclic loading tests,the effects...Based on the results of seven corroded reinforced concrete(RC)shear walls with a high shear-span ratio under an artificial climatic environment(ACE)that were subjected to pseudo-static cyclic loading tests,the effects of corrosion degree,as well as the reinforcement ratio of horizontal distribution bars and boundary columns longitudinal bars on seismic performance of corroded RC shear walls were investigated.The experimental results show that the strength,stiffness,ductility and energy-dissipating capacity of the specimen lessened with the raising of corrosion degree.As the horizontal distribution reinforcement ratio improved,bearing capability was slightly enhanced,and the deformation and energy dissipation capacities of the specimens were markedly increased.With the rising boundary column longitudinal reinforcement ratio,the bearing capacity,stiffness degradation rate and cumulative energy consumption of the specimens intensified,and deformability was not significantly increased.After contemplating the correction of corroded materials and the buckling effect of corroded longitudinal bars,a finite element model of corroded RC shear walls was created on the basis of ShellMITC4 layered shell elements.Eventually,employing the constructed numerical model,the variation laws of other parameters on the seismic performance of the corroded RC shear wall were revealed.展开更多
Study on artificial cultivation of Tricholoma matsutake carried through by the present research group in Changbai Mountains in recent years was briefly reviewed in the paper, and then, the signifycance of cultivation....Study on artificial cultivation of Tricholoma matsutake carried through by the present research group in Changbai Mountains in recent years was briefly reviewed in the paper, and then, the signifycance of cultivation. Mechanism of formation, hiberarchy, grouwth cycle and suitable living environment, were summarized.展开更多
文摘With the springing up of new technologies and materials in aircraft,the thermal management of aircraft is facing the dilemma of heat load increase and effective heat sink decrease.Hence the limiting factor of certain advanced aircraft is gradually changing from fuel to heat,and increasing emphasis on addressing the issue of aircraft environmental control should be placed.To reduce the energy consumption and improve the endurance of aircraft systems,this study reviews the development of aircraft environmental control technologies and analyzes the solutions in a human-machine cooperative manner.The comfortable temperature and humidity for personnel is generally between 18∼29℃and 20%∼30%respectively,and the normal working temperature of equipment is usually 15∼90℃.Using multiple indexes to evaluate the personnel comfort,equipment cooling and system energy consumption levels of existing aircraft environmental control technologies,it is found that the environmental needs of personnel and equipment cabin can be basically met with significant progress made in various technologies,e.g.equipment cooling,dehumidification and humidification,anti-freeze defrost and etc.Whereas there is rare research on the energy cascading utilization technology for human-machine synergistic environment and there exists challenges in applying the environmental control technology for cooling high-powered equipment to the personnel cabin.Finally,it is proposed that the future aircraft environmental control should develop cascading energy utilization,efficient cooling and shared control technologies,to take advantages of the humanmachine collaborative regulation and cope with the challenges caused by transient thermal load impacts on the system.
基金National Natural Science Foundation of China under Grant No.52278530National Key R&D Program of China under Grant No.2019YFC1509302Key R&D Project of Shaanxi Province under Grant No.2021ZDLSF06-10。
文摘Based on the results of seven corroded reinforced concrete(RC)shear walls with a high shear-span ratio under an artificial climatic environment(ACE)that were subjected to pseudo-static cyclic loading tests,the effects of corrosion degree,as well as the reinforcement ratio of horizontal distribution bars and boundary columns longitudinal bars on seismic performance of corroded RC shear walls were investigated.The experimental results show that the strength,stiffness,ductility and energy-dissipating capacity of the specimen lessened with the raising of corrosion degree.As the horizontal distribution reinforcement ratio improved,bearing capability was slightly enhanced,and the deformation and energy dissipation capacities of the specimens were markedly increased.With the rising boundary column longitudinal reinforcement ratio,the bearing capacity,stiffness degradation rate and cumulative energy consumption of the specimens intensified,and deformability was not significantly increased.After contemplating the correction of corroded materials and the buckling effect of corroded longitudinal bars,a finite element model of corroded RC shear walls was created on the basis of ShellMITC4 layered shell elements.Eventually,employing the constructed numerical model,the variation laws of other parameters on the seismic performance of the corroded RC shear wall were revealed.
文摘Study on artificial cultivation of Tricholoma matsutake carried through by the present research group in Changbai Mountains in recent years was briefly reviewed in the paper, and then, the signifycance of cultivation. Mechanism of formation, hiberarchy, grouwth cycle and suitable living environment, were summarized.
