A high-temperature and high-pressure valve is the key equipment of a wind tunnel system;it controls the generation of high-temperature and high-pressure gas.To reduce the adverse impact of high-temperature and high-pr...A high-temperature and high-pressure valve is the key equipment of a wind tunnel system;it controls the generation of high-temperature and high-pressure gas.To reduce the adverse impact of high-temperature and high-pressure gas on the strength of the valve body,a cooling structure is set on the valve seat.This can significantly reduce the temperature of the valve body and valve seat.The effects of its structure on the cooling characteristics and stress of the valve seat are studied,and six main parameters that can completely describe the geometry of the cooling structure are proposed.The central composite design method is used to select sample points,and the multi-objective genetic algorithm(MOGA)method is used for optimal structural design.A modification method according to the main parameters for the valve seat is proposed.The results show that the cooling structure weakens the pressure-bearing capability of the valve seat.Among the six main parameters of the valve seat,the distance from the end face of the lower hole to the Z-axis and the distance from the axis of the lower hole to the origin of the coordinates have the most obvious effects on the average stress of the valve seat.An optimum design value is proposed.This work can provide a reference for the design of high-temperature and high-pressure valves.展开更多
Ultrathin two-dimensional （2D） porous Zn（OH）2 nanosheets （PNs） were fabricated by means of one-dimensional Cu nanowires as backbones. The PNs have thickness of approximately 3.8 nm and pore size of 4-10 nm. To f...Ultrathin two-dimensional （2D） porous Zn（OH）2 nanosheets （PNs） were fabricated by means of one-dimensional Cu nanowires as backbones. The PNs have thickness of approximately 3.8 nm and pore size of 4-10 nm. To form ＂smart＂ porous nanosheets, DNA aptamers were covalently conjugated to the surface of PNs. These ultrathin nanosheets show good biocompatibility, effident cellular uptaker and promising pH-stimulated drug release.展开更多
基金supported by the National Natural Science Foundation of China(No.52175067)the Zhejiang Key Research&Development Project(No.2021C01021)+1 种基金the Natural Science Foundation of Zhejiang Province(No.LY20E050016)the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(CPSF)(No.GZC20241478)。
文摘A high-temperature and high-pressure valve is the key equipment of a wind tunnel system;it controls the generation of high-temperature and high-pressure gas.To reduce the adverse impact of high-temperature and high-pressure gas on the strength of the valve body,a cooling structure is set on the valve seat.This can significantly reduce the temperature of the valve body and valve seat.The effects of its structure on the cooling characteristics and stress of the valve seat are studied,and six main parameters that can completely describe the geometry of the cooling structure are proposed.The central composite design method is used to select sample points,and the multi-objective genetic algorithm(MOGA)method is used for optimal structural design.A modification method according to the main parameters for the valve seat is proposed.The results show that the cooling structure weakens the pressure-bearing capability of the valve seat.Among the six main parameters of the valve seat,the distance from the end face of the lower hole to the Z-axis and the distance from the axis of the lower hole to the origin of the coordinates have the most obvious effects on the average stress of the valve seat.An optimum design value is proposed.This work can provide a reference for the design of high-temperature and high-pressure valves.
基金The authors are grateful to Dr. Kathryn Williams for her critical comments during the preparation of this manuscript. This work is supported by grants awarded by the National Institutes of Health （No. GM079359 and CA133086）. This work is also supported by the National Basic Research Program of China （No. 2011CB911000）, National Natural Science Foundation of China （Nos. 21221003 and 21327009） and China National Instrumentation Program （No. 2011YQ03012412）.
文摘Ultrathin two-dimensional （2D） porous Zn（OH）2 nanosheets （PNs） were fabricated by means of one-dimensional Cu nanowires as backbones. The PNs have thickness of approximately 3.8 nm and pore size of 4-10 nm. To form ＂smart＂ porous nanosheets, DNA aptamers were covalently conjugated to the surface of PNs. These ultrathin nanosheets show good biocompatibility, effident cellular uptaker and promising pH-stimulated drug release.
