[Objective] The aim of this study was to investigate the content changes and their correlations of the photosynthetic pigment,phenols,including total phenols,total flavonoids and anthocyanins,and total saponins of the...[Objective] The aim of this study was to investigate the content changes and their correlations of the photosynthetic pigment,phenols,including total phenols,total flavonoids and anthocyanins,and total saponins of the one-year-old P.notoginseng plants under supplemental UV-B stress in fields.[Method] The one-year-old plants were irradiated by UV-B in field for 1 min per day,and the plants under the UV-B lamp were regarded as a circle center,achieving an annular leaf-sampling.The photosynthetic pigment,phenols and total saponins of the leaves were determined spectrophotometrically.[Result] With the increase of sampling radius,the supplemental UV-B intensity decreased significantly,the contents of chlorophyll （Chl） a,Chl b,Chl （a＋b）,carotenoid （Car） and total photosynthetic pigment （Chl＋Car） of the leaves increased extremely significantly,the Chl a/b and total phenol content （TPC） decreased extremely significantly,but the Chl （a＋b）/Car changes were not significant.The contents of total flavonoids,anthocyanins and saponins all increased due to the increasing of UV-B,displaying dose effects.The UV-B intensity was positively correlated with the Chl a/b,and negatively with the Chl a,Chl b,Chl （a＋ b）,Car and （Chl＋Car） contents; and the two of TPC,total flavonoid content （TFC）,total anthocyanin content （TAC） and total saponin content （TSC） were positively correlated,all reaching extremely significant level.The UV-B intensity was positively and significantly correlated with the total flavonoid content （TFC）,negatively and significantly with the Chl （a＋b）/Car,and positively and insignificantly with the TPC,TAC and TSC.[Conclusion] For one-year-old plants of P.notoginseng,UV-B can decrease the contents of the Chl a,Chl b,Chl （a＋b）,Car and （Chl＋Car） and increase the Chl a/b and TPC,and,furthermore,induce the increases of the TFC,TAC and TSC in a dose-dependent manner.However,UV-B can hardly change the Chl （a＋b）/Car.The supplemental UV-B of well-suited dose might be one of the effective measures to improve the TSC of P.notoginseng.展开更多
[Objective] This study was to realize high-density culture of Chlorella sp. as well as the culture with high lipid yield. [Method] Through analyzing the growth curve of Chlorella sp. cells, dextrose consumption curve,...[Objective] This study was to realize high-density culture of Chlorella sp. as well as the culture with high lipid yield. [Method] Through analyzing the growth curve of Chlorella sp. cells, dextrose consumption curve, change curves of pH and dissolved oxygen, a fed-batch culture was conducted, followed by a nitrogen-deficient culture aiming at accumulating the lipids in Chlorella sp. cells when a high density of Chlorella sp. cells was obtained. [Result] After four batches of feeding were pro- vided, the biomass of Chlorella sp. reached up to 65.25 g/L, and the lipid content increased from 42.75% to 63.82% in Chlorella sp. cells, with the yield of 43.37 g/L in the following 12 hours of nitrogen-deficient culture. [Conclusion] Reasonable fed- batch can significantly improve the biomass of Chlorella sp., and the nitrogen-defi- cient culture further raises the lipid yield of Chlorella sp.展开更多
On the basis of detailed analysis of a novel harmonic counteracting method which can be used to effectively compensate the supply line harmonic currents of a passive single phase diode bridge rectifier, this paper pr...On the basis of detailed analysis of a novel harmonic counteracting method which can be used to effectively compensate the supply line harmonic currents of a passive single phase diode bridge rectifier, this paper presents two simpler single phase diode bridge rectifier configurations and their alternatives which can achieve low supply line current THD(total harmonic distortion) too. Moreover, this paper also proposes a few passive hamonic counteracting networks for multi single phase rectifiers which are connected in parallel.展开更多
The Upper Chao Phraya River Basin, Thailand, has been facing continuous groundwater level decreases due to over-extraction for irrigation. MAR （managed aquifer recharge） using infiltration pond was investigated and ...The Upper Chao Phraya River Basin, Thailand, has been facing continuous groundwater level decreases due to over-extraction for irrigation. MAR （managed aquifer recharge） using infiltration pond was investigated and constructed. A recharge experiment at the pilot site at Ban Nong Na, Phitsanulok Province, was conducted during 2009 to 2011 to mitigate the declining shallow groundwater level. The HELP3 and MODFLOW models were applied to explore the current groundwater recharge. The MODFLOW was used to simulate the recharge mechanism of the experiment in the 1,260 m2 infiltration pond during July to November, 2010. The simulated results showed the groundwater influx and outflux for the year 2010 were 1.34 Mm3 1.57 Mm3, respectively. The annual shallow groundwater extraction was 1.40 Mm3 resulting in the groundwater system deficit of 0.23 Mm3 and causing groundwater level decline at the rate of 0.25 m/yr. The critical zone with groundwater level deeper than 8 m from the ground surface covers 19% of the study area of 4.12 km2 and it would be increased up to 85% within the next 10 years （2020）. To achieve the groundwater system balance, the deficit amount of 0.23 Mm3 is needed and six infiltration ponds are required.展开更多
基金Supported by the National Natural Science Foundation of China(31060045,31260091)~~
文摘[Objective] The aim of this study was to investigate the content changes and their correlations of the photosynthetic pigment,phenols,including total phenols,total flavonoids and anthocyanins,and total saponins of the one-year-old P.notoginseng plants under supplemental UV-B stress in fields.[Method] The one-year-old plants were irradiated by UV-B in field for 1 min per day,and the plants under the UV-B lamp were regarded as a circle center,achieving an annular leaf-sampling.The photosynthetic pigment,phenols and total saponins of the leaves were determined spectrophotometrically.[Result] With the increase of sampling radius,the supplemental UV-B intensity decreased significantly,the contents of chlorophyll （Chl） a,Chl b,Chl （a＋b）,carotenoid （Car） and total photosynthetic pigment （Chl＋Car） of the leaves increased extremely significantly,the Chl a/b and total phenol content （TPC） decreased extremely significantly,but the Chl （a＋b）/Car changes were not significant.The contents of total flavonoids,anthocyanins and saponins all increased due to the increasing of UV-B,displaying dose effects.The UV-B intensity was positively correlated with the Chl a/b,and negatively with the Chl a,Chl b,Chl （a＋ b）,Car and （Chl＋Car） contents; and the two of TPC,total flavonoid content （TFC）,total anthocyanin content （TAC） and total saponin content （TSC） were positively correlated,all reaching extremely significant level.The UV-B intensity was positively and significantly correlated with the total flavonoid content （TFC）,negatively and significantly with the Chl （a＋b）/Car,and positively and insignificantly with the TPC,TAC and TSC.[Conclusion] For one-year-old plants of P.notoginseng,UV-B can decrease the contents of the Chl a,Chl b,Chl （a＋b）,Car and （Chl＋Car） and increase the Chl a/b and TPC,and,furthermore,induce the increases of the TFC,TAC and TSC in a dose-dependent manner.However,UV-B can hardly change the Chl （a＋b）/Car.The supplemental UV-B of well-suited dose might be one of the effective measures to improve the TSC of P.notoginseng.
文摘[Objective] This study was to realize high-density culture of Chlorella sp. as well as the culture with high lipid yield. [Method] Through analyzing the growth curve of Chlorella sp. cells, dextrose consumption curve, change curves of pH and dissolved oxygen, a fed-batch culture was conducted, followed by a nitrogen-deficient culture aiming at accumulating the lipids in Chlorella sp. cells when a high density of Chlorella sp. cells was obtained. [Result] After four batches of feeding were pro- vided, the biomass of Chlorella sp. reached up to 65.25 g/L, and the lipid content increased from 42.75% to 63.82% in Chlorella sp. cells, with the yield of 43.37 g/L in the following 12 hours of nitrogen-deficient culture. [Conclusion] Reasonable fed- batch can significantly improve the biomass of Chlorella sp., and the nitrogen-defi- cient culture further raises the lipid yield of Chlorella sp.
文摘On the basis of detailed analysis of a novel harmonic counteracting method which can be used to effectively compensate the supply line harmonic currents of a passive single phase diode bridge rectifier, this paper presents two simpler single phase diode bridge rectifier configurations and their alternatives which can achieve low supply line current THD(total harmonic distortion) too. Moreover, this paper also proposes a few passive hamonic counteracting networks for multi single phase rectifiers which are connected in parallel.
文摘The Upper Chao Phraya River Basin, Thailand, has been facing continuous groundwater level decreases due to over-extraction for irrigation. MAR （managed aquifer recharge） using infiltration pond was investigated and constructed. A recharge experiment at the pilot site at Ban Nong Na, Phitsanulok Province, was conducted during 2009 to 2011 to mitigate the declining shallow groundwater level. The HELP3 and MODFLOW models were applied to explore the current groundwater recharge. The MODFLOW was used to simulate the recharge mechanism of the experiment in the 1,260 m2 infiltration pond during July to November, 2010. The simulated results showed the groundwater influx and outflux for the year 2010 were 1.34 Mm3 1.57 Mm3, respectively. The annual shallow groundwater extraction was 1.40 Mm3 resulting in the groundwater system deficit of 0.23 Mm3 and causing groundwater level decline at the rate of 0.25 m/yr. The critical zone with groundwater level deeper than 8 m from the ground surface covers 19% of the study area of 4.12 km2 and it would be increased up to 85% within the next 10 years （2020）. To achieve the groundwater system balance, the deficit amount of 0.23 Mm3 is needed and six infiltration ponds are required.
