Newton's polynomial interpolation may be the favorite linear interpolation,associated continued fractions interpolation is a new type nonlinear interpolation.We use those two interpolation to construct a new kind of ...Newton's polynomial interpolation may be the favorite linear interpolation,associated continued fractions interpolation is a new type nonlinear interpolation.We use those two interpolation to construct a new kind of bivariate blending rational interpolants.Characteristic theorem is discussed.We give some new blending interpolation formulae.展开更多
极小种群植物扣树(Ilex kaushue S. Y. Hu)是分布于中国南方的特有树种,易受到气候变化的影响。为加强扣树的保护,有必要研究气候变暖背景下其生境适宜性范围的变化。通过对10种物种分布模型的预测精度进行对比,选择3种预测性能较好的...极小种群植物扣树(Ilex kaushue S. Y. Hu)是分布于中国南方的特有树种,易受到气候变化的影响。为加强扣树的保护,有必要研究气候变暖背景下其生境适宜性范围的变化。通过对10种物种分布模型的预测精度进行对比,选择3种预测性能较好的物种分布模型(GBM、MaxEnt和RF)的平均值来评估气候变暖对扣树生境适宜性的影响。当前气候下扣树适宜生境区的预测结果表明,扣树的分布较为集中,最冷月最低温度(bio6)、降雨量季节性变化(bio15)和最干旱月降雨量(bio14)对模型贡献最大,说明扣树对温度和降水较为敏感。在未来气候情景下,扣树的生境适宜区呈现向北迁移的趋势,适宜分布范围存在不同程度的缩小;预测到2070年,随着温室气体排放增加,扣树的适生范围由RCP2.6情景下的92.70%缩小到RCP8.5情景下的51.52%,特别是在低纬度的海南省, 4种情景的平均适生生境缩减了93.67%。因此,在制定极小种群植物扣树的保护策略时应考虑气候变暖的影响。展开更多
该文基于双馈风电机组(doubly-fed induction generator,DFIG),在电网电压对称骤升下,对电网电压与转子电流之间的暂态过程进行详细的理论推导,提出一种有效抑制转子过电流的控制策略,并针对网侧变换器传统控制方法作出相应的改进。在...该文基于双馈风电机组(doubly-fed induction generator,DFIG),在电网电压对称骤升下,对电网电压与转子电流之间的暂态过程进行详细的理论推导,提出一种有效抑制转子过电流的控制策略,并针对网侧变换器传统控制方法作出相应的改进。在不增加任何硬件设备的情况下,转子侧和网侧分别附加转子电流抑制(rotor current suppression,RCS)和外环电网电压控制(grid voltage suppression,GVS)措施,并给出详细的控制框图。该控制方法不仅可以减少Crowbar装置频繁动作致使转子侧变换器快速短接的问题,而且充分发挥风电机组自身的动态无功支撑能力,保证风电机组在电网电压故障骤升期间不脱网运行,有效提高双馈风力发电机的高电压穿越(high voltage ride through,HVRT)能力及风电机组运行的可靠性。最后,在PSCAD/EMTDC中对所提出的控制策略进行仿真建模分析,验证了该控制方案的有效性和可行性。展开更多
We construct general structures of one and two variable interpolation function, without depending on the existence of divided difference or inverse differences, and we also discuss the block based osculatory interpola...We construct general structures of one and two variable interpolation function, without depending on the existence of divided difference or inverse differences, and we also discuss the block based osculatory interpolation in one variable case. Clearly, our method offers marly flexible interpolation schemes for choices. Error terms for the interpolation are determined and numerical examples are given to show the effectlveness of the results.展开更多
基金Supported by the Project Foundation of the Department of Education of Anhui Province(KJ2008A027,KJ2010B182,KJ2011B152,KJ2011B137)Supported by the Grant of Scientific Research Foundation for Talents of Hefei University(11RC05)Supported by the Grant of Scientific Research Foundation Hefei University(11KY06ZR)
文摘Newton's polynomial interpolation may be the favorite linear interpolation,associated continued fractions interpolation is a new type nonlinear interpolation.We use those two interpolation to construct a new kind of bivariate blending rational interpolants.Characteristic theorem is discussed.We give some new blending interpolation formulae.
文摘极小种群植物扣树(Ilex kaushue S. Y. Hu)是分布于中国南方的特有树种,易受到气候变化的影响。为加强扣树的保护,有必要研究气候变暖背景下其生境适宜性范围的变化。通过对10种物种分布模型的预测精度进行对比,选择3种预测性能较好的物种分布模型(GBM、MaxEnt和RF)的平均值来评估气候变暖对扣树生境适宜性的影响。当前气候下扣树适宜生境区的预测结果表明,扣树的分布较为集中,最冷月最低温度(bio6)、降雨量季节性变化(bio15)和最干旱月降雨量(bio14)对模型贡献最大,说明扣树对温度和降水较为敏感。在未来气候情景下,扣树的生境适宜区呈现向北迁移的趋势,适宜分布范围存在不同程度的缩小;预测到2070年,随着温室气体排放增加,扣树的适生范围由RCP2.6情景下的92.70%缩小到RCP8.5情景下的51.52%,特别是在低纬度的海南省, 4种情景的平均适生生境缩减了93.67%。因此,在制定极小种群植物扣树的保护策略时应考虑气候变暖的影响。
文摘该文基于双馈风电机组(doubly-fed induction generator,DFIG),在电网电压对称骤升下,对电网电压与转子电流之间的暂态过程进行详细的理论推导,提出一种有效抑制转子过电流的控制策略,并针对网侧变换器传统控制方法作出相应的改进。在不增加任何硬件设备的情况下,转子侧和网侧分别附加转子电流抑制(rotor current suppression,RCS)和外环电网电压控制(grid voltage suppression,GVS)措施,并给出详细的控制框图。该控制方法不仅可以减少Crowbar装置频繁动作致使转子侧变换器快速短接的问题,而且充分发挥风电机组自身的动态无功支撑能力,保证风电机组在电网电压故障骤升期间不脱网运行,有效提高双馈风力发电机的高电压穿越(high voltage ride through,HVRT)能力及风电机组运行的可靠性。最后,在PSCAD/EMTDC中对所提出的控制策略进行仿真建模分析,验证了该控制方案的有效性和可行性。
基金The Grant (11RC05) of Scienti/fic Research Foundation for Talents of Hefei Universitythe Grant (11KY06ZR) of Scientific Research Foundation Hefei University+1 种基金the Key Project Foundation (KJ2008A027) of the Department of Education of Anhui Provincethe Project Foundation (KJ2010B182,KJ2011B152, KJ2011B137) of the Department of Education of Anhui Province
文摘We construct general structures of one and two variable interpolation function, without depending on the existence of divided difference or inverse differences, and we also discuss the block based osculatory interpolation in one variable case. Clearly, our method offers marly flexible interpolation schemes for choices. Error terms for the interpolation are determined and numerical examples are given to show the effectlveness of the results.