The size and shape of rice grains influence their yield and commercial value.We investigated the role of OsDA1,a rice homolog of the Arabidopsis DA1 gene,in regulating grain size and shape.OsDA1 was highly expressed i...The size and shape of rice grains influence their yield and commercial value.We investigated the role of OsDA1,a rice homolog of the Arabidopsis DA1 gene,in regulating grain size and shape.OsDA1 was highly expressed in young spikelets and glumes.Its overexpression led to enlarged seeds with increased width and decreased length/width ratio(LWR)and knocking out OsDA1 reduced grain width and increased grain length and LWR.A R310K point mutation in the DA1-like domain is a potential target for breeding for increased grain width and length.OsDA1 interacted with TCP gene-family proteins to regulate grain size and shape.Our findings deepen our understanding of the molecular mechanisms underlying grain size regulation and provide useful information for improving grain yield.展开更多
The research was conducted to determine the relationships of protein and starch accumulation dynamics in grains of wheat to post-heading leaf SPAD values and canopy spectral reflectance. The results showed that leaf n...The research was conducted to determine the relationships of protein and starch accumulation dynamics in grains of wheat to post-heading leaf SPAD values and canopy spectral reflectance. The results showed that leaf nitrogen accumulation was exponentially related to leaf SPAD values and linearly related to canopy spectral reflectance, and that there was negative linear relationship between leaf nitrogen accumulation and grain protein accumulation, but positive linear relationship between post-heading leaf nitrogen transloca-tion and grain protein accumulation at maturity. In addition, leaf SPAD values were parabolically related with and ratio indices R(l 500,610)and R(l 220,560)were exponentially related with protein and starch accumulation in grains. These results indicate that leaf SPAD values and canopy spectral reflectance should be good indicators of quality formation dynamics in wheat grains.展开更多
The microstructure and mechanical properties of AZ31 Mg alloy processed by high ratio extrusion (HRE) were investigated. General extrusion with extrusion ratio of 7 and high ratio extrusion with extrusion ratio 100 we...The microstructure and mechanical properties of AZ31 Mg alloy processed by high ratio extrusion (HRE) were investigated. General extrusion with extrusion ratio of 7 and high ratio extrusion with extrusion ratio 100 were contrastively conducted at 250,300 and 350℃. The results show that HRE process may be applied successfully to AZ31 Mg alloy at temperatures of 250, 300 and 350℃and this leads to obvious grain refinement during HRE process. The strength of HRE process is improved obviously compared with that of general extrusion. The grain refining mechanism of HRE process was also discussed. The current results imply that the simple high ratio extrusion method might be a feasible and effective processing means for refining the microstructure and improving the mechanical properties of AZ31 Mg alloy.展开更多
The modern Yellow River delta is formed near the estuary of the Yellow River with the characteristics of short formation time, efficient sedimentation rate and loose structure which make sediments prone to be compacte...The modern Yellow River delta is formed near the estuary of the Yellow River with the characteristics of short formation time, efficient sedimentation rate and loose structure which make sediments prone to be compacted and consolidate under the geostatic stress and overburden stress. It is one of the key areas with land subsidence disasters in China, bringing a series of safety hazards to production and living. Based on the data of massive surface cores and ten drill holes ranging from 12 to 40 m obtained from the northern modern Yellow River subaqueous delta, the inversion method suitable for the calculation of consolidation settlement characteristics of the modern Yellow River subaqueous delta is discussed, and the consolidation settlement characteristics of the delta sediments are inversed and predicted in this paper. The actual void ratio of the delta sediments at the depth from 3 to 15 m shows a significant power function relationship with the depth, while the void ratio of the sediments below 15 m changes little with depth. The pre-consolidation settlement(from deposition to sampling) of the delta sediments is between 0.91 and 1.96 m, while the consolidation settlement of unit depth is between 9.6 and 14.0 cm m^(-1). The post-consolidation settlement(from sampling to stable) of the subaqueous delta sediments is between 0.65 and 1.56 m in the later stage, and the consolidation settlement of unit depth is between 7.6 and 13.1 cm m^(-1) under the overburden stress. The delta sediments with a buried depth of 3 to 7 m contribute the most to the possible consolidation settlement in the later stage.展开更多
In order to examine the effect of extrusion ratio on the microstructure and mechanical behavior in Al-Cu-Mg-Ag alloy, the Al-6.3 Cu-0.48 Mg-0.4 Ag alloy was subjected to extruding with different extrusion ratios of 17...In order to examine the effect of extrusion ratio on the microstructure and mechanical behavior in Al-Cu-Mg-Ag alloy, the Al-6.3 Cu-0.48 Mg-0.4 Ag alloy was subjected to extruding with different extrusion ratios of 17, 30 and 67. The results indicate that the grains are refined and the strength is improved effectively with increasing extrusion ratio. However, further investigation shows that the extrusion ratio of 30 is more effective than the lower extrusion ratio(17) and the higher extrusion ratio(67) to refine the grains in the T6-temper alloy. Moreover, the sample with an extrusion ratio of 30 obtains more precipitates and superior mechanical properties after T6 treatment. This study supports the idea that there exists a critical extrusion ratio for grain refinement and improvement of mechanical properties for the T6-temper alloy. Recrystallization and precipitation during T6 treatment were introduced to explain the effects of extrusion ratio on the microstructure and mechanical properties of the Al-Cu-Mg-Ag alloys.展开更多
Field studies (location Au pits, sampling of different layers of sedimentary sequences filling the pits, panning of sediments), litho-stratigraphic investigations, grain size analysis and outlining of depositional con...Field studies (location Au pits, sampling of different layers of sedimentary sequences filling the pits, panning of sediments), litho-stratigraphic investigations, grain size analysis and outlining of depositional conditions revealed a characteristic fining upward sequence in all the sections of 08 Au-pits within the Betare Oya basin. A typical profile is 2.5 to 4.5 m thick and is composed of a 30 to 50 cm organic topsoil layer, underlain by a 1.5 m thick reddish brownish gold free saprolite, which is underlain by 1.5 m sandy section. From litho-stratigraphic investigations and grain size analysis results a quartz dominated gravelly 1.4 m thick layer consisting in boulders (275 mm), cobbles (2-−0.0148x2 + 1.2187x + 2.0344, R2 = 0.6929 (sandy layer);2) y = 0.0617x2 + 1.0849x + 0.8097, R2 = 0.8694 (gravelly layer);and y > R2 is satisfied in both cases. This implies that Au recovery from these layers could be effective through gravity separation using sieves mounted on classifiers of 7 cm (sandy layer) and 10 cm (gravelly layer) diameter.展开更多
Determination of the critical state line(CSL)is important to characterize engineering properties of granular soils.Grain size distribution(GSD)has a significant influence on the location of CSL.The influence of partic...Determination of the critical state line(CSL)is important to characterize engineering properties of granular soils.Grain size distribution(GSD)has a significant influence on the location of CSL.The influence of particle breakage on the CSL is mainly attributed to the change in GSD due to particle breakage.However,GSD has not been properly considered in modeling the CSL with influence of particle breakage.This study aims to propose a quantitative model to determine the CSL considering the effect of GSD.We hypothesize that the change of critical state void ratio with respect to GSD is caused by the same mechanism that influences of the change of minimum void ratio with respect to GSD.Consequently,the particle packing model for minimum void ratio proposed by Chang et al.(2017)is extended to predict critical state void ratio.The developed model is validated by experimental results of CSLs for several types of granular materials.Then the evolution of GSD due to particle breakage is incorporated into the model.The model is further evaluated using the experimental results on rockfill material,which illustrates the applicability of the model in predicting CSL for granular material with particle breakage.展开更多
基金This work is supported in part by the National Transgenic Science and Technology Program(2016ZX08010-002)National Natural Science Foundation of China(157101834)Agricultural Science and Technology Innovation Program of CAAS.
文摘The size and shape of rice grains influence their yield and commercial value.We investigated the role of OsDA1,a rice homolog of the Arabidopsis DA1 gene,in regulating grain size and shape.OsDA1 was highly expressed in young spikelets and glumes.Its overexpression led to enlarged seeds with increased width and decreased length/width ratio(LWR)and knocking out OsDA1 reduced grain width and increased grain length and LWR.A R310K point mutation in the DA1-like domain is a potential target for breeding for increased grain width and length.OsDA1 interacted with TCP gene-family proteins to regulate grain size and shape.Our findings deepen our understanding of the molecular mechanisms underlying grain size regulation and provide useful information for improving grain yield.
基金supported by the National High Tech R&D Program,China(863 Program,2002AA243011)the National Natural Science Foundation of China(30030090)the Natural Science Foundation of Jiangsu Province,China(BK2003079).
文摘The research was conducted to determine the relationships of protein and starch accumulation dynamics in grains of wheat to post-heading leaf SPAD values and canopy spectral reflectance. The results showed that leaf nitrogen accumulation was exponentially related to leaf SPAD values and linearly related to canopy spectral reflectance, and that there was negative linear relationship between leaf nitrogen accumulation and grain protein accumulation, but positive linear relationship between post-heading leaf nitrogen transloca-tion and grain protein accumulation at maturity. In addition, leaf SPAD values were parabolically related with and ratio indices R(l 500,610)and R(l 220,560)were exponentially related with protein and starch accumulation in grains. These results indicate that leaf SPAD values and canopy spectral reflectance should be good indicators of quality formation dynamics in wheat grains.
基金Project (50674067) supported by the National Natural Science Foundation of China
文摘The microstructure and mechanical properties of AZ31 Mg alloy processed by high ratio extrusion (HRE) were investigated. General extrusion with extrusion ratio of 7 and high ratio extrusion with extrusion ratio 100 were contrastively conducted at 250,300 and 350℃. The results show that HRE process may be applied successfully to AZ31 Mg alloy at temperatures of 250, 300 and 350℃and this leads to obvious grain refinement during HRE process. The strength of HRE process is improved obviously compared with that of general extrusion. The grain refining mechanism of HRE process was also discussed. The current results imply that the simple high ratio extrusion method might be a feasible and effective processing means for refining the microstructure and improving the mechanical properties of AZ31 Mg alloy.
基金financially supported by the Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology (No. MGQNLM-KF20 1715)the National Natural Science Foundation of ChinaShandong Joint Fund for Marine Science Research Centers (No. U1606401)+1 种基金the Special Fund of Chinese Central Government for Basic Scientific Research Operations in Commonweal Research Institutes (No. 2015G08)the National Science Foundation for Young Scientists of China (No. 41206054)
文摘The modern Yellow River delta is formed near the estuary of the Yellow River with the characteristics of short formation time, efficient sedimentation rate and loose structure which make sediments prone to be compacted and consolidate under the geostatic stress and overburden stress. It is one of the key areas with land subsidence disasters in China, bringing a series of safety hazards to production and living. Based on the data of massive surface cores and ten drill holes ranging from 12 to 40 m obtained from the northern modern Yellow River subaqueous delta, the inversion method suitable for the calculation of consolidation settlement characteristics of the modern Yellow River subaqueous delta is discussed, and the consolidation settlement characteristics of the delta sediments are inversed and predicted in this paper. The actual void ratio of the delta sediments at the depth from 3 to 15 m shows a significant power function relationship with the depth, while the void ratio of the sediments below 15 m changes little with depth. The pre-consolidation settlement(from deposition to sampling) of the delta sediments is between 0.91 and 1.96 m, while the consolidation settlement of unit depth is between 9.6 and 14.0 cm m^(-1). The post-consolidation settlement(from sampling to stable) of the subaqueous delta sediments is between 0.65 and 1.56 m in the later stage, and the consolidation settlement of unit depth is between 7.6 and 13.1 cm m^(-1) under the overburden stress. The delta sediments with a buried depth of 3 to 7 m contribute the most to the possible consolidation settlement in the later stage.
基金Funded by the National Natural Science Foundation of China(No.51071075)the Deep Continental Scientific Drilling Equipment Development(Sino Probe-09-05)by the 985 Project-Automotive Engineering of Jilin University
文摘In order to examine the effect of extrusion ratio on the microstructure and mechanical behavior in Al-Cu-Mg-Ag alloy, the Al-6.3 Cu-0.48 Mg-0.4 Ag alloy was subjected to extruding with different extrusion ratios of 17, 30 and 67. The results indicate that the grains are refined and the strength is improved effectively with increasing extrusion ratio. However, further investigation shows that the extrusion ratio of 30 is more effective than the lower extrusion ratio(17) and the higher extrusion ratio(67) to refine the grains in the T6-temper alloy. Moreover, the sample with an extrusion ratio of 30 obtains more precipitates and superior mechanical properties after T6 treatment. This study supports the idea that there exists a critical extrusion ratio for grain refinement and improvement of mechanical properties for the T6-temper alloy. Recrystallization and precipitation during T6 treatment were introduced to explain the effects of extrusion ratio on the microstructure and mechanical properties of the Al-Cu-Mg-Ag alloys.
文摘Field studies (location Au pits, sampling of different layers of sedimentary sequences filling the pits, panning of sediments), litho-stratigraphic investigations, grain size analysis and outlining of depositional conditions revealed a characteristic fining upward sequence in all the sections of 08 Au-pits within the Betare Oya basin. A typical profile is 2.5 to 4.5 m thick and is composed of a 30 to 50 cm organic topsoil layer, underlain by a 1.5 m thick reddish brownish gold free saprolite, which is underlain by 1.5 m sandy section. From litho-stratigraphic investigations and grain size analysis results a quartz dominated gravelly 1.4 m thick layer consisting in boulders (275 mm), cobbles (2-−0.0148x2 + 1.2187x + 2.0344, R2 = 0.6929 (sandy layer);2) y = 0.0617x2 + 1.0849x + 0.8097, R2 = 0.8694 (gravelly layer);and y > R2 is satisfied in both cases. This implies that Au recovery from these layers could be effective through gravity separation using sieves mounted on classifiers of 7 cm (sandy layer) and 10 cm (gravelly layer) diameter.
基金supported by the National Science Foundation of the United States under a research grant (CMMI-1917238)
文摘Determination of the critical state line(CSL)is important to characterize engineering properties of granular soils.Grain size distribution(GSD)has a significant influence on the location of CSL.The influence of particle breakage on the CSL is mainly attributed to the change in GSD due to particle breakage.However,GSD has not been properly considered in modeling the CSL with influence of particle breakage.This study aims to propose a quantitative model to determine the CSL considering the effect of GSD.We hypothesize that the change of critical state void ratio with respect to GSD is caused by the same mechanism that influences of the change of minimum void ratio with respect to GSD.Consequently,the particle packing model for minimum void ratio proposed by Chang et al.(2017)is extended to predict critical state void ratio.The developed model is validated by experimental results of CSLs for several types of granular materials.Then the evolution of GSD due to particle breakage is incorporated into the model.The model is further evaluated using the experimental results on rockfill material,which illustrates the applicability of the model in predicting CSL for granular material with particle breakage.