The effects of different carbon sources(sugars) on the production and molecular properties of exopolysaccharides(EPS) were evaluated in the mycelial liquid culture of a medicinal fungus Cordyceps sinensis Cs-HK1. Gala...The effects of different carbon sources(sugars) on the production and molecular properties of exopolysaccharides(EPS) were evaluated in the mycelial liquid culture of a medicinal fungus Cordyceps sinensis Cs-HK1. Galactose or mannose was used(at 5 g·L^(-1)) as a secondary carbon source with glucose(35 g·L^(-1)) at the mass ratio of 1:7. Mannose was consumed notably since the first day of culture, but galactose was not even after glucose was exhausted.The volumetric yield of EPS in culture was increased slightly with the addition of galactose and decreased with mannose. The monosaccharide composition of EPS was also different, e.g., on day 8, the glucose contents of EPS were 76%with the addition of mannose, 59% with galactose, compared with 62% with glucose only. The molecular weight distribution of EPS was also affected by the secondary carbon source, being generally lower compared with that with glucose only. The results suggested that the addition of galactose improved the total yield of EPS in culture while mannose can improve the yield of glucan constituent of EPS.展开更多
A major challenge in Ga N based solar cell design is the lack of holes compared with electrons in the multiple quantum wells(MQWs). We find that Ga N based MQW photovoltaic devices with five different Mg-doping concen...A major challenge in Ga N based solar cell design is the lack of holes compared with electrons in the multiple quantum wells(MQWs). We find that Ga N based MQW photovoltaic devices with five different Mg-doping concentrations of 0 cm-3, 5×1017 cm-3, 2×1018 cm-3, 4×1018 cm-3 and 7×1018 cm-3 in Ga N barriers can lead to different hole concentrations in quantum wells(QWs). However, when the Mg-doping concentration is over 1×1018 cm-3, the crystal quality degrades, which results in the reduction of the external quantum efficiency(EQE), short circuit current density and open circuit voltage. As a result, the sample with a slight Mg-doping concentration of 5×1017 cm-3 exhibits the highest conversion efficiency.展开更多
基金Supported by The Hong Kong Polytechnic University internal grants(G-UC14 and G-YBB4)
文摘The effects of different carbon sources(sugars) on the production and molecular properties of exopolysaccharides(EPS) were evaluated in the mycelial liquid culture of a medicinal fungus Cordyceps sinensis Cs-HK1. Galactose or mannose was used(at 5 g·L^(-1)) as a secondary carbon source with glucose(35 g·L^(-1)) at the mass ratio of 1:7. Mannose was consumed notably since the first day of culture, but galactose was not even after glucose was exhausted.The volumetric yield of EPS in culture was increased slightly with the addition of galactose and decreased with mannose. The monosaccharide composition of EPS was also different, e.g., on day 8, the glucose contents of EPS were 76%with the addition of mannose, 59% with galactose, compared with 62% with glucose only. The molecular weight distribution of EPS was also affected by the secondary carbon source, being generally lower compared with that with glucose only. The results suggested that the addition of galactose improved the total yield of EPS in culture while mannose can improve the yield of glucan constituent of EPS.
基金supported by the Key Scientific Research Project of Higher Education of Henan Province(No.15A510033)
文摘A major challenge in Ga N based solar cell design is the lack of holes compared with electrons in the multiple quantum wells(MQWs). We find that Ga N based MQW photovoltaic devices with five different Mg-doping concentrations of 0 cm-3, 5×1017 cm-3, 2×1018 cm-3, 4×1018 cm-3 and 7×1018 cm-3 in Ga N barriers can lead to different hole concentrations in quantum wells(QWs). However, when the Mg-doping concentration is over 1×1018 cm-3, the crystal quality degrades, which results in the reduction of the external quantum efficiency(EQE), short circuit current density and open circuit voltage. As a result, the sample with a slight Mg-doping concentration of 5×1017 cm-3 exhibits the highest conversion efficiency.
