The oxidation behavior of alloy 690 exposed to high-temperature and high-pressure steam and water at 280℃ for 1 h was investigated by scanning electron microscopy （SEM）, atomic force microscopy （AFM） and X-ray ph...The oxidation behavior of alloy 690 exposed to high-temperature and high-pressure steam and water at 280℃ for 1 h was investigated by scanning electron microscopy （SEM）, atomic force microscopy （AFM） and X-ray photoelectron spectroscopy （XPS）. In high-temperature and high-pressure steam, the oxide film is composed of an outermost Ni-rich hydroxides layer, an intermediate layer of hydroxides and oxides enriched in Cr, an inner oxide layer. The film formed in high-temperature water is similar to that in steam, except for missing the Ni-rich hydroxides layer. Samples with different surface finishes （electropolished, mechanically polished, ground, and as-received） were prepared for comparison. A general increase of the oxide thickness with the degree of surface roughness is observed. The equivalent oxide thicknesses lie in the range of 100-200 nm for the as-received samples, 150-250 nm for the samples ground to 400# and 10-20 nm for the samples ground to 1500#, mechanically polished, and electropolished.展开更多
There have been considerable advances in the understanding of species concepts in the genus Colletotrichum.This has lead to the need to carry out fresh surveys of Colletotrichum species associated with important hosts...There have been considerable advances in the understanding of species concepts in the genus Colletotrichum.This has lead to the need to carry out fresh surveys of Colletotrichum species associated with important hosts.Colletotrichum species are associated with Citrus plants as saprobes,important pre-harvest and post-harvest pathogens,as well as endophytes.In this study,a total of 312 Colletotrichum strains were isolated from leaves,shoots and fruits of cultivated Citrus and Fortunella species with or without disease symptoms across the main citrus production areas in China.The morphology of all strains were studied and multilocus(ACT,TUB2,CAL,GAPDH,GS,ITS)phylogeny established.Strains were from four important species complexes of Colletotrichum,namely C.gloeosporioides species complex,C.boninense species complex,C.acutatum species complex and a final group including C.truncatum,which was rare on Citrus species.The species belonging to the C.gloeosporioides species complex comprised C.gloeos porioides and C.fructicola,the C.boninense complex comprised C.karstii and a new species C.citricola and the C.acutatum complex included a new species,C.citri.The ability of strains to cause anthracnose on citrus fruits was tested by inoculation and strains of Colletotrichum gloeosporioides,C.fructicola and C.truncatum were pathogenic.展开更多
基金supported by the Special Funds for the Major State Basic Research Projects(G2011CB610502)the National Natural Science Foundation of China (No.51025104)
文摘The oxidation behavior of alloy 690 exposed to high-temperature and high-pressure steam and water at 280℃ for 1 h was investigated by scanning electron microscopy （SEM）, atomic force microscopy （AFM） and X-ray photoelectron spectroscopy （XPS）. In high-temperature and high-pressure steam, the oxide film is composed of an outermost Ni-rich hydroxides layer, an intermediate layer of hydroxides and oxides enriched in Cr, an inner oxide layer. The film formed in high-temperature water is similar to that in steam, except for missing the Ni-rich hydroxides layer. Samples with different surface finishes （electropolished, mechanically polished, ground, and as-received） were prepared for comparison. A general increase of the oxide thickness with the degree of surface roughness is observed. The equivalent oxide thicknesses lie in the range of 100-200 nm for the as-received samples, 150-250 nm for the samples ground to 400# and 10-20 nm for the samples ground to 1500#, mechanically polished, and electropolished.
基金supported by the China Agriculture Research System (CARS-27)L. Cai acknowledges grantsKSCX2-YW-Z-1026 ⁄ NSFC31070020K.D. Hyde thanks theNational Research Council of Thailand, Colletotrichum grant number54201020003 for financial support.
文摘There have been considerable advances in the understanding of species concepts in the genus Colletotrichum.This has lead to the need to carry out fresh surveys of Colletotrichum species associated with important hosts.Colletotrichum species are associated with Citrus plants as saprobes,important pre-harvest and post-harvest pathogens,as well as endophytes.In this study,a total of 312 Colletotrichum strains were isolated from leaves,shoots and fruits of cultivated Citrus and Fortunella species with or without disease symptoms across the main citrus production areas in China.The morphology of all strains were studied and multilocus(ACT,TUB2,CAL,GAPDH,GS,ITS)phylogeny established.Strains were from four important species complexes of Colletotrichum,namely C.gloeosporioides species complex,C.boninense species complex,C.acutatum species complex and a final group including C.truncatum,which was rare on Citrus species.The species belonging to the C.gloeosporioides species complex comprised C.gloeos porioides and C.fructicola,the C.boninense complex comprised C.karstii and a new species C.citricola and the C.acutatum complex included a new species,C.citri.The ability of strains to cause anthracnose on citrus fruits was tested by inoculation and strains of Colletotrichum gloeosporioides,C.fructicola and C.truncatum were pathogenic.
