With rapid growth of power demand, transmission capacity is also in urgent need of upgrading. In some cases, converting existing AC transmission lines to DC lines can Improve the transmission capacity and reduce the c...With rapid growth of power demand, transmission capacity is also in urgent need of upgrading. In some cases, converting existing AC transmission lines to DC lines can Improve the transmission capacity and reduce the construction investment. In this paper, the upstream finite element method was expanded to calculate the total electric field of same tower multi-circuit DC lines converted from double-circuit AC lines, and the validity of the algorithm was confirmed by experiments. Taking a DC line converted from a typical same tower 500 kV double-circuit AC transmission line as an example, the surface electric field and the ground total electric field in different pole conductor arrangement schemes were calculated and analyzed, and the critical height of pole conductors for DC lines in residential and non-residential area were determined. Then, the corridor width of DC and AC lines at critical height in residential and non-residential areas before and after AC-DC line transformation were compared. The results indicate that for DC lines converted from common 500 kV double-circuit AC lines, the ground total electric field can meet the requirements of corresponding standard with appropriate pole conductor arrangement schemes.展开更多
[Objective] The study was to analyze functional components in improved barley grains. [Method] Genetic variations of functional components in grains among 629 barley improved lines from four continents were determined...[Objective] The study was to analyze functional components in improved barley grains. [Method] Genetic variations of functional components in grains among 629 barley improved lines from four continents were determined with DU640-type ultraviolet spectrophotometry (BECKMAN). [Result] The contents (mg/100 g) of total flavones and GABA in grains of Asian barley lines (123.09±29.56, 9.49±4.34) were significantly higher than that of American barley lines (103.85±22.33, 7.38±3.59), while no significant difference was observed between Asia/Americas and Europe (115.47±11.41, 9.66±3.98) and Australia (104.20±4.76, 8.83±3.41); furthermore, there was no significant difference of resistant starch content (%) in barley grains among four continents [Asia (1.63±1.44), America (1.54±1.13), Europe (1.20±0.85) and Australia (0.27±0.26)]. The contents (%) of resistant starch in grains of two-rowed barley (ssp. Hordeum distichon Koern., 1.45±1.20) was significantly lower than that of poly-rowed barley (ssp. Hordeum vulgare Orlov., 1.95±1.24). On the contrary, the content of total flavones in two-rowed lines (111.43±27.79 mg/100 g) was significantly higher than that of poly-rowed lines (102.15±14.95 mg/100 g), and the content of GABA in two-rowed lines (8.55±3.73 mg/100 g) was also significantly higher than that of poly-rowed lines (5.96±3.95 mg/100 g). There was the most significant correlation between GABA content and resistant starch (-0.21**)/total flavones content (0.12**, P<0.01, n=629). There were great genotype differences among the functional components in barley grains. The coefficient of variation (78.60%) and range (0-9.29%) of resistant starch (1.56±1.22%) were relatively large, including 11 high-resistant starch lines above 5%; the coefficient of variation (49.00%) and range (0-30.67 mg/100g) of GABA (8.00±3.92 mg/100 g) were also relatively large, including 26 lines with GABA higher than 15 mg/100 g; the coefficient of variation (23.63%) and range (58.44-236.91 mg/100 g) of total flavones (109.44±25.85 mg/100 g) was relatively small, including 14 lines with total flavones higher than 176 mg/100 g. [Conclusion] There are zonal and genotypic differences in the contents of of functional components in barley grains.展开更多
文摘With rapid growth of power demand, transmission capacity is also in urgent need of upgrading. In some cases, converting existing AC transmission lines to DC lines can Improve the transmission capacity and reduce the construction investment. In this paper, the upstream finite element method was expanded to calculate the total electric field of same tower multi-circuit DC lines converted from double-circuit AC lines, and the validity of the algorithm was confirmed by experiments. Taking a DC line converted from a typical same tower 500 kV double-circuit AC transmission line as an example, the surface electric field and the ground total electric field in different pole conductor arrangement schemes were calculated and analyzed, and the critical height of pole conductors for DC lines in residential and non-residential area were determined. Then, the corridor width of DC and AC lines at critical height in residential and non-residential areas before and after AC-DC line transformation were compared. The results indicate that for DC lines converted from common 500 kV double-circuit AC lines, the ground total electric field can meet the requirements of corresponding standard with appropriate pole conductor arrangement schemes.
文摘[Objective] The study was to analyze functional components in improved barley grains. [Method] Genetic variations of functional components in grains among 629 barley improved lines from four continents were determined with DU640-type ultraviolet spectrophotometry (BECKMAN). [Result] The contents (mg/100 g) of total flavones and GABA in grains of Asian barley lines (123.09±29.56, 9.49±4.34) were significantly higher than that of American barley lines (103.85±22.33, 7.38±3.59), while no significant difference was observed between Asia/Americas and Europe (115.47±11.41, 9.66±3.98) and Australia (104.20±4.76, 8.83±3.41); furthermore, there was no significant difference of resistant starch content (%) in barley grains among four continents [Asia (1.63±1.44), America (1.54±1.13), Europe (1.20±0.85) and Australia (0.27±0.26)]. The contents (%) of resistant starch in grains of two-rowed barley (ssp. Hordeum distichon Koern., 1.45±1.20) was significantly lower than that of poly-rowed barley (ssp. Hordeum vulgare Orlov., 1.95±1.24). On the contrary, the content of total flavones in two-rowed lines (111.43±27.79 mg/100 g) was significantly higher than that of poly-rowed lines (102.15±14.95 mg/100 g), and the content of GABA in two-rowed lines (8.55±3.73 mg/100 g) was also significantly higher than that of poly-rowed lines (5.96±3.95 mg/100 g). There was the most significant correlation between GABA content and resistant starch (-0.21**)/total flavones content (0.12**, P<0.01, n=629). There were great genotype differences among the functional components in barley grains. The coefficient of variation (78.60%) and range (0-9.29%) of resistant starch (1.56±1.22%) were relatively large, including 11 high-resistant starch lines above 5%; the coefficient of variation (49.00%) and range (0-30.67 mg/100g) of GABA (8.00±3.92 mg/100 g) were also relatively large, including 26 lines with GABA higher than 15 mg/100 g; the coefficient of variation (23.63%) and range (58.44-236.91 mg/100 g) of total flavones (109.44±25.85 mg/100 g) was relatively small, including 14 lines with total flavones higher than 176 mg/100 g. [Conclusion] There are zonal and genotypic differences in the contents of of functional components in barley grains.
