Morphology and crystal structure of β precipitate phase in Mg-7Gd-5Y-1Nd-0.5Zr (mass fraction, %) alloy were characterized by optical microscopy, scanning electron microscopy and transmission electron microscopy. Com...Morphology and crystal structure of β precipitate phase in Mg-7Gd-5Y-1Nd-0.5Zr (mass fraction, %) alloy were characterized by optical microscopy, scanning electron microscopy and transmission electron microscopy. Compositions were determined for β phase using thin foil energy dispersive spectroscopy. Precipitation at 400 ℃ involves formation of platelet and block-shaped β phase. The orientation relationship is and between β precipitate phase and α-Mg matrix with habit planes parallel to , and a composition of Mg5(Y0.4Gd0.4Nd0.2) is suggested for the β phase in Mg-7Gd-5Y-1Nd-0.5Zr alloy.展开更多
The seasonal and interannual variations of the vertical distribution of the Kuroshio velocity and its formative mechanism were studied by analyzing the Global Ocean Reanalysis Simulation 2 （GLORYS2） dataset in the P...The seasonal and interannual variations of the vertical distribution of the Kuroshio velocity and its formative mechanism were studied by analyzing the Global Ocean Reanalysis Simulation 2 （GLORYS2） dataset in the Pollution Nagasaki （PN） section （126.0°E-128.2°, at depths less than 1000 m）. The results indicated that： 1） the maximum transport in the PN section occurs in summer, followed by spring, and the minimum transport occurs in fall and winter; the maximum velocities are located at the subsurface in both winter and summer and velocities are relatively larger and at a shallower depth in summer; and the velocity core is located at the surface in spring and fall. The isopycnic line has a clear depression around the Kuroshio axis in winter. The depth of maximum velocity and the zero horizontal density gradients both exhibit substantial seasonal and interannual variations, and the interannual variations are larger. 2） The distributions of velocity and density are in accordance with the therma~ wind relation. Although Kuroshio transport is determined by the large-scale wind field and mesoscale motion in the Pacific Ocean; local heat flux and thermohaline circulation influence the density field, modify the vertical structure of the Kuroshio velocity, and adjust the allocation of water fluxes and nutrients transport. 3） Shelf-water offshore transport into the Kuroshio upper layer induced by southwest monsoons might contribute to the maximum velocity up to the surface in summer. Nonlinear and nongeostrophic processes are not considered in the present study, and the thermal wind relation accounts for part of the vertical structure of the Kuroshio velocity.展开更多
[Objective] This study was conducted to explore the internal relationship among root biological traits of sweetpotato, as well as the regularity in their formation and differentiation. [Method] The root traits of 10 s...[Objective] This study was conducted to explore the internal relationship among root biological traits of sweetpotato, as well as the regularity in their formation and differentiation. [Method] The root traits of 10 sweetpotato cultivars were measured through hydroponic culture in a greenhouse and field survey, and then their correlations were analyzed by statistical methods. [Result] The root morphological traits of sweetpotato at seedling stage such as projected area, surface area, average diameter and volume processed the highest contribution rate （80.56%） 10 d after transplanting, and the contribution rate of root average diameter reached 27.79% 20 d after transplanting. Storage root fresh weight per plant shared extremely significant positive correlations with storage root fresh weight of penultimate node and storage root fresh weight of antepenultimate node, and a significant positive corre- lation with commercial storage root number, and a significant negative correlation with storage root number of penultimate node. Among them, the correlation coeffi- cient of storage root fresh weight per plant with storage root fresh weight of antepenultimate node was the highest （0.659 5）. Fifteen days after transplanting, storage root fresh weight per plant had significant negative correlations with root projected area, surface area and volume. There was a significant positive correlation between root dry weight and storage root fresh weight per plant 25 d after transplanting. Root dry weight, volume, length, average diameter of sweetpotato seedlings had higher relational degrees with storage root fresh weight per plant. Ten and twenty days after transplanting were important time for the growth and differentiation of sweetpotato roots. In addition, node length and planting depth had certain influence on sweetpotato yield, and direct relationship existed between the seedling root biological traits and storage root yield of sweetpotato. [Conclusion] The results provide theoretical support for standard cultivation and new variety breeding of sweetpotato.展开更多
Using reanalysis data provided by the U.S. National Centers for Environmental Prediction/National Center for Atmospheric Research, the potential relationship between the E1 Nifio-Southern Oscillation （ENSO） cycle an...Using reanalysis data provided by the U.S. National Centers for Environmental Prediction/National Center for Atmospheric Research, the potential relationship between the E1 Nifio-Southern Oscillation （ENSO） cycle and blocking highs in three key regions of Eurasia （Ural, Baikal, and Okhotsk） from 1950 to 2008 is analyzed. Composite analysis of 500 hPa geopotential height field during different stages of ENSO reveals that in the winters of E1 Nifio （EN） years, there is significant negative anomaly of geopotential height in the three key regions. In the winters of La Nifia （LN） years, on the other hand, significant positive anomaly of geopotential height is observed in Eastern Ural, Baikal, and Okhotsk. In summer, Okhotsk exhibits positive anomaly, which is significant at a confidence level of 90% by Student＇s t-test during the developing stage of an LN year. In the developing stage of an EN year, geopotential height field at 500 hPa manifests positive （negative） anomaly in Baikal （Ural and Okhotsk）, while the geopotential height field at 500 hPa exhibits positive （negative） anomaly in Ural and Okhotsk （Baikal） during the decaying stage of both EN and LN years. However, these abnormities are insignificant in a developing EN year, decaying EN year, and the summer of a decaying LN year. By analyzing 500 hPa geopotential height field during different phases of the ENSO cycle, it is observed that results of the case study are consistent with those of composite analysis. Annual average blocking is likewise examined during the different stages of ENSO from 1950 to 2008. Combined with composite analysis and case study, results indicate that blockings in the three key regions are suppressed （enhanced） during the winters of EN （LN） years. In summer, the influence of ENSO on the blockings in the three key regions is not as significant as that in winter. Evidently, developing LN may enhance blockings in Okhotsk. Influence factors on blockings are various and complex. This paper indicates that the influence of ENSO on blockings cannot be neglected, and that it is crucial to related operational forecasting as a potential signal.展开更多
基金Project (2011DAE22B01) supported by the Key Technologies Program of China during the 12th Fire-Year Plan Period
文摘Morphology and crystal structure of β precipitate phase in Mg-7Gd-5Y-1Nd-0.5Zr (mass fraction, %) alloy were characterized by optical microscopy, scanning electron microscopy and transmission electron microscopy. Compositions were determined for β phase using thin foil energy dispersive spectroscopy. Precipitation at 400 ℃ involves formation of platelet and block-shaped β phase. The orientation relationship is and between β precipitate phase and α-Mg matrix with habit planes parallel to , and a composition of Mg5(Y0.4Gd0.4Nd0.2) is suggested for the β phase in Mg-7Gd-5Y-1Nd-0.5Zr alloy.
文摘The seasonal and interannual variations of the vertical distribution of the Kuroshio velocity and its formative mechanism were studied by analyzing the Global Ocean Reanalysis Simulation 2 （GLORYS2） dataset in the Pollution Nagasaki （PN） section （126.0°E-128.2°, at depths less than 1000 m）. The results indicated that： 1） the maximum transport in the PN section occurs in summer, followed by spring, and the minimum transport occurs in fall and winter; the maximum velocities are located at the subsurface in both winter and summer and velocities are relatively larger and at a shallower depth in summer; and the velocity core is located at the surface in spring and fall. The isopycnic line has a clear depression around the Kuroshio axis in winter. The depth of maximum velocity and the zero horizontal density gradients both exhibit substantial seasonal and interannual variations, and the interannual variations are larger. 2） The distributions of velocity and density are in accordance with the therma~ wind relation. Although Kuroshio transport is determined by the large-scale wind field and mesoscale motion in the Pacific Ocean; local heat flux and thermohaline circulation influence the density field, modify the vertical structure of the Kuroshio velocity, and adjust the allocation of water fluxes and nutrients transport. 3） Shelf-water offshore transport into the Kuroshio upper layer induced by southwest monsoons might contribute to the maximum velocity up to the surface in summer. Nonlinear and nongeostrophic processes are not considered in the present study, and the thermal wind relation accounts for part of the vertical structure of the Kuroshio velocity.
文摘[Objective] This study was conducted to explore the internal relationship among root biological traits of sweetpotato, as well as the regularity in their formation and differentiation. [Method] The root traits of 10 sweetpotato cultivars were measured through hydroponic culture in a greenhouse and field survey, and then their correlations were analyzed by statistical methods. [Result] The root morphological traits of sweetpotato at seedling stage such as projected area, surface area, average diameter and volume processed the highest contribution rate （80.56%） 10 d after transplanting, and the contribution rate of root average diameter reached 27.79% 20 d after transplanting. Storage root fresh weight per plant shared extremely significant positive correlations with storage root fresh weight of penultimate node and storage root fresh weight of antepenultimate node, and a significant positive corre- lation with commercial storage root number, and a significant negative correlation with storage root number of penultimate node. Among them, the correlation coeffi- cient of storage root fresh weight per plant with storage root fresh weight of antepenultimate node was the highest （0.659 5）. Fifteen days after transplanting, storage root fresh weight per plant had significant negative correlations with root projected area, surface area and volume. There was a significant positive correlation between root dry weight and storage root fresh weight per plant 25 d after transplanting. Root dry weight, volume, length, average diameter of sweetpotato seedlings had higher relational degrees with storage root fresh weight per plant. Ten and twenty days after transplanting were important time for the growth and differentiation of sweetpotato roots. In addition, node length and planting depth had certain influence on sweetpotato yield, and direct relationship existed between the seedling root biological traits and storage root yield of sweetpotato. [Conclusion] The results provide theoretical support for standard cultivation and new variety breeding of sweetpotato.
基金Key project of the medium-range forecasting technology of the destructive weather (freezing temperatures, rains, snows and cold damages) from China Meteorological Administration (CMATG20092D02)Key Project of National Science and Technology Support Program (2007BAC29B03)
文摘Using reanalysis data provided by the U.S. National Centers for Environmental Prediction/National Center for Atmospheric Research, the potential relationship between the E1 Nifio-Southern Oscillation （ENSO） cycle and blocking highs in three key regions of Eurasia （Ural, Baikal, and Okhotsk） from 1950 to 2008 is analyzed. Composite analysis of 500 hPa geopotential height field during different stages of ENSO reveals that in the winters of E1 Nifio （EN） years, there is significant negative anomaly of geopotential height in the three key regions. In the winters of La Nifia （LN） years, on the other hand, significant positive anomaly of geopotential height is observed in Eastern Ural, Baikal, and Okhotsk. In summer, Okhotsk exhibits positive anomaly, which is significant at a confidence level of 90% by Student＇s t-test during the developing stage of an LN year. In the developing stage of an EN year, geopotential height field at 500 hPa manifests positive （negative） anomaly in Baikal （Ural and Okhotsk）, while the geopotential height field at 500 hPa exhibits positive （negative） anomaly in Ural and Okhotsk （Baikal） during the decaying stage of both EN and LN years. However, these abnormities are insignificant in a developing EN year, decaying EN year, and the summer of a decaying LN year. By analyzing 500 hPa geopotential height field during different phases of the ENSO cycle, it is observed that results of the case study are consistent with those of composite analysis. Annual average blocking is likewise examined during the different stages of ENSO from 1950 to 2008. Combined with composite analysis and case study, results indicate that blockings in the three key regions are suppressed （enhanced） during the winters of EN （LN） years. In summer, the influence of ENSO on the blockings in the three key regions is not as significant as that in winter. Evidently, developing LN may enhance blockings in Okhotsk. Influence factors on blockings are various and complex. This paper indicates that the influence of ENSO on blockings cannot be neglected, and that it is crucial to related operational forecasting as a potential signal.
