The morphology of early allergic contact dermatitis reactions was studied in formaldehyde allergic individuals exposed to a cream product preserved with 4 different concentrations of diazolidinyl urea. The study was m...The morphology of early allergic contact dermatitis reactions was studied in formaldehyde allergic individuals exposed to a cream product preserved with 4 different concentrations of diazolidinyl urea. The study was made using a dose-escalating design in 3 different anatomical regions, the upper arm, neck and face. On the arm and neck, the dominant initial morphology was an eczematous papular eruption. In the face, the initial skin changes were more homogeneous and infiltrated erythema.展开更多
In this study,the rotary movement of the tungsten needle in gas tungsten arc welding(GTAW)process was realized by direct current motor.The arc characteristics,the flow of molten pool and the microstructure and propert...In this study,the rotary movement of the tungsten needle in gas tungsten arc welding(GTAW)process was realized by direct current motor.The arc characteristics,the flow of molten pool and the microstructure and properties of the weld bead were studied.The results showed that the rotary motion of the tungsten needle transferred circumferential momentum to the arc as well as the molten pool,thereby conferring the latter with rotating fluid flow characteristics.Under the action of a relatively spiraling shielding gas,arc constriction occurred,and molten pool width dropped considerably.A finer and more uniform precipitated phase in the matrix,as well as a fewer large-medium pores,were achieved in the 5A06 aluminum alloy weld metal using this modified GTAW process,which noticeably increased the bending strength and tensile strength of weld metal and the microhardness of fusion zone.展开更多
文摘The morphology of early allergic contact dermatitis reactions was studied in formaldehyde allergic individuals exposed to a cream product preserved with 4 different concentrations of diazolidinyl urea. The study was made using a dose-escalating design in 3 different anatomical regions, the upper arm, neck and face. On the arm and neck, the dominant initial morphology was an eczematous papular eruption. In the face, the initial skin changes were more homogeneous and infiltrated erythema.
基金supported by National Natural Science Foundation of China(52175305)National Natural Science Foundation of China(U22B20127)Taishan Scholars Project(tstp20230618).
文摘In this study,the rotary movement of the tungsten needle in gas tungsten arc welding(GTAW)process was realized by direct current motor.The arc characteristics,the flow of molten pool and the microstructure and properties of the weld bead were studied.The results showed that the rotary motion of the tungsten needle transferred circumferential momentum to the arc as well as the molten pool,thereby conferring the latter with rotating fluid flow characteristics.Under the action of a relatively spiraling shielding gas,arc constriction occurred,and molten pool width dropped considerably.A finer and more uniform precipitated phase in the matrix,as well as a fewer large-medium pores,were achieved in the 5A06 aluminum alloy weld metal using this modified GTAW process,which noticeably increased the bending strength and tensile strength of weld metal and the microhardness of fusion zone.
