The microstructure and tensile properties of Sn-9Zn solder under different cooling and aging condition were studied. During solidification,the distribution of Zn-rich phases and grain size in the microstructure of Sn-...The microstructure and tensile properties of Sn-9Zn solder under different cooling and aging condition were studied. During solidification,the distribution of Zn-rich phases and grain size in the microstructure of Sn-9Zn solder were decided by the cooling rate. The Zn-rich phase in Sn-9Zn solder under furnace cooling,air cooling and water cooling media was separately existed as coarsen dendritic and needle like shape,fine needle like shape and very fine rod-like shape,respectively. After aging,the coarsen dendritic was broken and the coarsen needle like Zn-rich phase was partly changed into fine distribution of Zn-rich phase for Sn-9Zn solder with furnace cooling,and the rod-like Zn phase in the Sn-9Zn solder under water cooling was changed to conglomerated Zn with needle shape. During tensile testing on Sn-9Zn solder,tensile strength and ductility reached the best with water cooling,but decreased with aging effect. Meanwhile,the ductility of solder with air cooling and the strength of solder with furnace cooling increased with aging. The fracture mode was ductile and was independent of cooling media and aging effect. The size and depth of dimples decreased from water,furnace to air cooling.After aging,number and size of dimples increased on the solder with furnace cooling and air cooling. The change on the size of dimples for the Sn-9Zn solder under different cooling condition and with aging effect was accordance to the tensile properties.展开更多
Mating behavior is crucial for most insects,as it is closely tied to reproduction and population growth and relies heavily on chemical communication via cuticular hydrocarbons(CHCs)between individuals.However,little i...Mating behavior is crucial for most insects,as it is closely tied to reproduction and population growth and relies heavily on chemical communication via cuticular hydrocarbons(CHCs)between individuals.However,little is known about the mating behavior of Eupeodes corollae,a natural enemy insect,and how CHCs help it communicate.In this study,we performed a behavioral assay of the mating process of hoverfly E.corollae.The cuticular hydrocarbons of both male and female hoverflies were identified by gas chromatography-mass spectrometry(GC-MS).The electrophysiological activities of these compounds on the antennae of hoverflies were further determined by gas chromatography coupled with electroantennogram detection(GC-EAD)and electroantennogram(EAG).The effects of these compounds on the behavioral selection and mating of hoverflies were also determined.The results showed that the mating process of hoverflies was divided into five stages:orientation,approaching,wing fanning,mounting,and copulation.Fifth-aged individuals exhibited the highest copulation and mating success rates,the shortest male latency,and stable mating duration.The results of the determination of cuticular compounds showed that the CHCs of male and female hoverflies exhibited sexually monomorphic chemical profiles,and two compounds of(Z)-9-tricosene and n-tricosane could cause significant electrophysiological responses in both male and female hoverflies.Behavioral bioassay results showed that(Z)-9-tricosene can significantly induce the attraction response of male and female E.corollae and can effectively regulate the courtship behavior of male E.corollae.This finding provides a new perspective for a deeper understanding of hoverflies'chemical communication mechanism and a valuable scientific basis and potential application prospect for developing a pheromone-based behavior strategy to control pests.展开更多
Fifteen subspecies of the wood tiger moth, Arctia plantaginis (Lepidoptera: Erebidae: Arctiinae), have been recorded in the Northern Hemisphere. An analysis of crude pheromone extracts by GC equipped with an electroan...Fifteen subspecies of the wood tiger moth, Arctia plantaginis (Lepidoptera: Erebidae: Arctiinae), have been recorded in the Northern Hemisphere. An analysis of crude pheromone extracts by GC equipped with an electroantennographic (EAG) detector showed four EAG-active components (Comps. I–IV) that were commonly involved in the pheromone glands of two subspecies inhabiting Japan and Finland. Comp. I is a major component (>75%) and the others are minor components (3% - 15%). Their mass spectra, measured by GC/MS, revealed the chemical structures of C21 unsaturated hydrocarbons as follows: 3,6,9-triene for Comp. I, 4,6,9-triene for Comp. II, 1,3,6,9-tetraene for Comp. III, and 2,4,6,9-tetraene for Comp. IV. Comps. I and III are known Type II pheromone compounds, and their retention times coincide with those of the authentic standards with all Z configurations. As a next step, the extract was analyzed by GC/FT-IR to determine the configuration of Comps. II and IV. Their IR spectra showed two characteristic C-H bending absorptions around 990 and 945 cm-1 due to the conjugated dienyl moieties;thus, Z and E configurations were assigned to the double bonds at the 2- and 4-positions, respectively. Their Z double bonds at the 6- and 9-positions are indicated by no absorptions around 970 cm-1, due to the isolated double bonds with E configurations. Finally, the structures of Comps. II and IV were confirmed by synthesis using a double Wittig reaction. The synthetic (4E,6Z,9Z)-4,6,9-triene and (2Z,4E,6Z,9Z)-2,4,6,9-tetraene showed strong EAG activity, and their chemical data coincided well with those of the natural Comps. II and IV, indicating the correctness of the structure determination by GC/FT-IR analysis and its usefulness for Type II pheromone compounds.展开更多
基金supported by the Natural Science Foundation of Jiangsu Province(Grant No.BK2012163)University Science Research Project of Jiangsu Province(Grant No.11KJB460003)
文摘The microstructure and tensile properties of Sn-9Zn solder under different cooling and aging condition were studied. During solidification,the distribution of Zn-rich phases and grain size in the microstructure of Sn-9Zn solder were decided by the cooling rate. The Zn-rich phase in Sn-9Zn solder under furnace cooling,air cooling and water cooling media was separately existed as coarsen dendritic and needle like shape,fine needle like shape and very fine rod-like shape,respectively. After aging,the coarsen dendritic was broken and the coarsen needle like Zn-rich phase was partly changed into fine distribution of Zn-rich phase for Sn-9Zn solder with furnace cooling,and the rod-like Zn phase in the Sn-9Zn solder under water cooling was changed to conglomerated Zn with needle shape. During tensile testing on Sn-9Zn solder,tensile strength and ductility reached the best with water cooling,but decreased with aging effect. Meanwhile,the ductility of solder with air cooling and the strength of solder with furnace cooling increased with aging. The fracture mode was ductile and was independent of cooling media and aging effect. The size and depth of dimples decreased from water,furnace to air cooling.After aging,number and size of dimples increased on the solder with furnace cooling and air cooling. The change on the size of dimples for the Sn-9Zn solder under different cooling condition and with aging effect was accordance to the tensile properties.
基金funded by the National Natural Science Foundation of China(32272621)the Key Project of Inter-Government International Science&Technology Innovation Cooperation,China(2019YFE0105800)+1 种基金the Major Special Projects for Green Pest Control,China(110202201017(LS-01))the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences。
文摘Mating behavior is crucial for most insects,as it is closely tied to reproduction and population growth and relies heavily on chemical communication via cuticular hydrocarbons(CHCs)between individuals.However,little is known about the mating behavior of Eupeodes corollae,a natural enemy insect,and how CHCs help it communicate.In this study,we performed a behavioral assay of the mating process of hoverfly E.corollae.The cuticular hydrocarbons of both male and female hoverflies were identified by gas chromatography-mass spectrometry(GC-MS).The electrophysiological activities of these compounds on the antennae of hoverflies were further determined by gas chromatography coupled with electroantennogram detection(GC-EAD)and electroantennogram(EAG).The effects of these compounds on the behavioral selection and mating of hoverflies were also determined.The results showed that the mating process of hoverflies was divided into five stages:orientation,approaching,wing fanning,mounting,and copulation.Fifth-aged individuals exhibited the highest copulation and mating success rates,the shortest male latency,and stable mating duration.The results of the determination of cuticular compounds showed that the CHCs of male and female hoverflies exhibited sexually monomorphic chemical profiles,and two compounds of(Z)-9-tricosene and n-tricosane could cause significant electrophysiological responses in both male and female hoverflies.Behavioral bioassay results showed that(Z)-9-tricosene can significantly induce the attraction response of male and female E.corollae and can effectively regulate the courtship behavior of male E.corollae.This finding provides a new perspective for a deeper understanding of hoverflies'chemical communication mechanism and a valuable scientific basis and potential application prospect for developing a pheromone-based behavior strategy to control pests.
文摘Fifteen subspecies of the wood tiger moth, Arctia plantaginis (Lepidoptera: Erebidae: Arctiinae), have been recorded in the Northern Hemisphere. An analysis of crude pheromone extracts by GC equipped with an electroantennographic (EAG) detector showed four EAG-active components (Comps. I–IV) that were commonly involved in the pheromone glands of two subspecies inhabiting Japan and Finland. Comp. I is a major component (>75%) and the others are minor components (3% - 15%). Their mass spectra, measured by GC/MS, revealed the chemical structures of C21 unsaturated hydrocarbons as follows: 3,6,9-triene for Comp. I, 4,6,9-triene for Comp. II, 1,3,6,9-tetraene for Comp. III, and 2,4,6,9-tetraene for Comp. IV. Comps. I and III are known Type II pheromone compounds, and their retention times coincide with those of the authentic standards with all Z configurations. As a next step, the extract was analyzed by GC/FT-IR to determine the configuration of Comps. II and IV. Their IR spectra showed two characteristic C-H bending absorptions around 990 and 945 cm-1 due to the conjugated dienyl moieties;thus, Z and E configurations were assigned to the double bonds at the 2- and 4-positions, respectively. Their Z double bonds at the 6- and 9-positions are indicated by no absorptions around 970 cm-1, due to the isolated double bonds with E configurations. Finally, the structures of Comps. II and IV were confirmed by synthesis using a double Wittig reaction. The synthetic (4E,6Z,9Z)-4,6,9-triene and (2Z,4E,6Z,9Z)-2,4,6,9-tetraene showed strong EAG activity, and their chemical data coincided well with those of the natural Comps. II and IV, indicating the correctness of the structure determination by GC/FT-IR analysis and its usefulness for Type II pheromone compounds.
