热处理作用下碳钢氢腐蚀裂纹愈合规律

对含氢腐蚀裂纹的碳钢进行再热处理后,SEM观察表明,氢蚀裂发生了不同程度的愈合,实验结果表明：长度约为10μm的碳钢氢蚀裂纹完全愈合的热处理条件下是从室温到1000℃热循环5次,共10h,氢蚀裂纹的愈合机制是热扩散,发生氢蚀裂纹愈合的动力是氢蚀气泡或裂纹长大导致的塑性变 能E8。在铁、碳和氢原子扩散都足够快的情况下,氢蚀裂纹愈合的条件是E8大于裂纹愈合所必须克服的表面张力能。     

Behavioural and electrophysiological evaluation of oviposition attractants forCulex quinquefasciatus say (Diptera: Culicidae)

The attraction of gravidCulex quinquefasciatus by the oviposition pheromone,erythro-6-acetoxy-5-hexadecanolide, and by polluted water is described. Both materials increase oviposition and when combined the effect is additive. The oviposition behaviour is reflected by the antennal sensitivity to these compounds.     

Enemy-induced dispersal in a parasitic wasp

Females of the parasitic waspAphidius uzbekistanicus, a specialist aphid primary parasitoid, react to the presence of their specialist hyperparasitoid enemyAlloxysta victrix by leaving the area. The wasps leave to increase their reproductive success, because only their offspring, but not the wasps themselves, are threatened by enemy attack. Furthermore, this dispersal is elicited through the action of volatile chemical cues produced by the hyperparasitoids. We provide evidence for 6-methyl-5-hepten-2-one being one of the volatiles eliciting dispersal. The tendency of the wasps to leave areas which are being colonized by their enemies reduces their efficiency as aphid antagonists.     

Mating attempts between the Scarlet Tiger Moth,Callimorpha dominula L., and the Cinnabar Moth,Tyria jacobaeae L. (Lepidoptera: Arctiidae), involve a common sex pheromone composition

It has been suggested that a common sex pheromone composition may account for interspecific sexual interactions observed with certain moths in the Arctiidae. In this study, it is demonstrated that the sex pheromones released by females of the Scarlet Tiger Moth,Callimorpha dominula L., and the Cinnabar Moth,Tyria jacobaeae L., have similar activities and elute at the same retention time on analysis by coupled gas chromatography (GC)-electrophysiology with males from each species. Peak enhancement on GC, chiral GC and coupled GC-mass spectrometry using authentic compounds show that the sex pheromone for bothC. dominula andT. jacobaeae is (3Z,6Z,9S,10R)-9,10-epoxyheneicosa-3,6-diene.