针对目前采用单一步长跟踪的最大功率跟踪(maximum power point tracking,MPPT)控制策略中,存在步长选取的差异无法兼得系统动态性能和稳态精度的问题,提出了恒压启动法与双指数函数步长算法结合的改进的MPPT控制策略。在启动时采用恒...针对目前采用单一步长跟踪的最大功率跟踪(maximum power point tracking,MPPT)控制策略中,存在步长选取的差异无法兼得系统动态性能和稳态精度的问题,提出了恒压启动法与双指数函数步长算法结合的改进的MPPT控制策略。在启动时采用恒定电压法快速定位在最大功率点(maximum power point,MPP)附近,然后利用双指数函数改变步长并精确跟踪光伏最大功率点,利用两种指数函数的函数特性实时调整MPP两侧的步长叠加量,进一步优化变步长跟踪效果。最后在MATLAB/Simulink平台中进行对比分析。结果表明:所提出的算法对提高光伏MPPT的快速性和减小稳态波动是有效的。展开更多
A series of soy protein isolate(SPI)films plasticized by glycerol(Gly)were studied using attenuated total reflectance-Fourier transform infrared spectroscopy(ATR/FTIR).Perturbation-correlation movingwindow two-dimensi...A series of soy protein isolate(SPI)films plasticized by glycerol(Gly)were studied using attenuated total reflectance-Fourier transform infrared spectroscopy(ATR/FTIR).Perturbation-correlation movingwindow two-dimensional(PCMW2D)and two-dimensional correlation(2DCOS)analyses were applied to the amideⅠband and thus the hydrogen bond interaction between SPI and Gly was systematically investigated.When Gly concentrations were in the range 0~35%,the hydrogen bond amongβ-sheets was replaced by the one between SPI chain and Gly molecule,which caused these protein chains being changed toα-helix.However,the transformation ofβ-sheet toα-helix was saturated and both of them tend to change to random coil when Gly concentrations were in the range 35%~60%.展开更多
利用第一次全国水利普查对湖北省水面面积10 km 2以上湖泊详查的测量成果,在外业测量和内业整理的基础上,统计了50个主要湖泊高水位条件下的湖泊面积、容积、湖泊岸线长度、湖长、湖泊宽度、平均水深;分析了湖泊的水面率、补给系数、发...利用第一次全国水利普查对湖北省水面面积10 km 2以上湖泊详查的测量成果,在外业测量和内业整理的基础上,统计了50个主要湖泊高水位条件下的湖泊面积、容积、湖泊岸线长度、湖长、湖泊宽度、平均水深;分析了湖泊的水面率、补给系数、发育系数、水深、面积及容积增长率等形态特征参数。湖北省的主要湖泊形态特征集中反映了湖北省湖泊水深浅、湖底平坦、坡度平缓、容积有限、调蓄能力较弱的特性。分析成果为湖北省湖泊的未来研究、开发、利用、保护以及促进区域经济社会可持续发展提供翔实的基础资料。展开更多
文摘针对目前采用单一步长跟踪的最大功率跟踪(maximum power point tracking,MPPT)控制策略中,存在步长选取的差异无法兼得系统动态性能和稳态精度的问题,提出了恒压启动法与双指数函数步长算法结合的改进的MPPT控制策略。在启动时采用恒定电压法快速定位在最大功率点(maximum power point,MPP)附近,然后利用双指数函数改变步长并精确跟踪光伏最大功率点,利用两种指数函数的函数特性实时调整MPP两侧的步长叠加量,进一步优化变步长跟踪效果。最后在MATLAB/Simulink平台中进行对比分析。结果表明:所提出的算法对提高光伏MPPT的快速性和减小稳态波动是有效的。
文摘A series of soy protein isolate(SPI)films plasticized by glycerol(Gly)were studied using attenuated total reflectance-Fourier transform infrared spectroscopy(ATR/FTIR).Perturbation-correlation movingwindow two-dimensional(PCMW2D)and two-dimensional correlation(2DCOS)analyses were applied to the amideⅠband and thus the hydrogen bond interaction between SPI and Gly was systematically investigated.When Gly concentrations were in the range 0~35%,the hydrogen bond amongβ-sheets was replaced by the one between SPI chain and Gly molecule,which caused these protein chains being changed toα-helix.However,the transformation ofβ-sheet toα-helix was saturated and both of them tend to change to random coil when Gly concentrations were in the range 35%~60%.
文摘利用第一次全国水利普查对湖北省水面面积10 km 2以上湖泊详查的测量成果,在外业测量和内业整理的基础上,统计了50个主要湖泊高水位条件下的湖泊面积、容积、湖泊岸线长度、湖长、湖泊宽度、平均水深;分析了湖泊的水面率、补给系数、发育系数、水深、面积及容积增长率等形态特征参数。湖北省的主要湖泊形态特征集中反映了湖北省湖泊水深浅、湖底平坦、坡度平缓、容积有限、调蓄能力较弱的特性。分析成果为湖北省湖泊的未来研究、开发、利用、保护以及促进区域经济社会可持续发展提供翔实的基础资料。