Seasonal polyphenism is a common phenomenon observed among members of the Lepidopteran subfamily Satyrinae. Melanitis leda, being a member of that subfamily, exhibits seasonal variation in terms of wing patterning. In...Seasonal polyphenism is a common phenomenon observed among members of the Lepidopteran subfamily Satyrinae. Melanitis leda, being a member of that subfamily, exhibits seasonal variation in terms of wing patterning. In butterflies, wing patterning is due to the nanostructural architecture of the scales, which reflects and refracts incident light, with or without the combination of pigments. The current scanning electron, fluorescence and optical microscope study divulge fine structural and signal changes that occur with different season in the scales of M. leda and give rise to the different wing pattern in butterfly. The structural and consequent signal changes are likely to be correlated with behavioural processes such as mate selection and escape from predation.展开更多
When analyzing the theme of"Leda and the Swan"written by William Butler Yeats, some scholar has concluded that the poem expresses Yeats's sexual desire for Maud Gonne and it is a work filled with an imag...When analyzing the theme of"Leda and the Swan"written by William Butler Yeats, some scholar has concluded that the poem expresses Yeats's sexual desire for Maud Gonne and it is a work filled with an imagination of his rape of her. However, this argument can be proved to be false from five respects:the different periods of Yeats's Poems;Yeats's life experience;the form of the poem;the tone of the poem;and its historical situation and Yeats's attitude toward the situation. Hence a poem should be inter-preted by returning to the text and should not be over-interpreted without taking into account its situation and related factors .展开更多
针对锁相环同步的弱连接电压源变流器(weakgrid connected voltage source converter,WG-VSC)系统的暂态稳定问题,该文首先应用线性矩阵不等式优化法构建WG-VSC系统的最大估计吸引域(largest estimated domain of attraction,LEDA),并将...针对锁相环同步的弱连接电压源变流器(weakgrid connected voltage source converter,WG-VSC)系统的暂态稳定问题,该文首先应用线性矩阵不等式优化法构建WG-VSC系统的最大估计吸引域(largest estimated domain of attraction,LEDA),并将LEDA与基于LaSalle不变集定理的能量函数法和平方和规划法构建的LEDA进行详细对比,验证了所提方法在刻画LEDA方面具有更低的保守性。然后从保证故障穿越控制过程中的锁相环暂态同步稳定作为切入点,首次提出WG-VSC系统在电网对称故障大扰动下的有功/无功电流设定值可行域概念,并基于线性矩阵不等式方法刻画的LEDA,提出该可行域的求解算法,分析了典型参数对该电流设定值可行域的影响。该可行域为故障过程中的有功和无功电流设定值提供了切实可行的指导依据。最后在PSCAD/EMTDC中搭建了基于详细开关模型的WG-VSC系统仿真算例,通过多种暂态仿真工况验证了该文所构建的LEDA和电流设定值可行域的有效性和可行性。展开更多
文摘Seasonal polyphenism is a common phenomenon observed among members of the Lepidopteran subfamily Satyrinae. Melanitis leda, being a member of that subfamily, exhibits seasonal variation in terms of wing patterning. In butterflies, wing patterning is due to the nanostructural architecture of the scales, which reflects and refracts incident light, with or without the combination of pigments. The current scanning electron, fluorescence and optical microscope study divulge fine structural and signal changes that occur with different season in the scales of M. leda and give rise to the different wing pattern in butterfly. The structural and consequent signal changes are likely to be correlated with behavioural processes such as mate selection and escape from predation.
文摘When analyzing the theme of"Leda and the Swan"written by William Butler Yeats, some scholar has concluded that the poem expresses Yeats's sexual desire for Maud Gonne and it is a work filled with an imagination of his rape of her. However, this argument can be proved to be false from five respects:the different periods of Yeats's Poems;Yeats's life experience;the form of the poem;the tone of the poem;and its historical situation and Yeats's attitude toward the situation. Hence a poem should be inter-preted by returning to the text and should not be over-interpreted without taking into account its situation and related factors .
文摘针对锁相环同步的弱连接电压源变流器(weakgrid connected voltage source converter,WG-VSC)系统的暂态稳定问题,该文首先应用线性矩阵不等式优化法构建WG-VSC系统的最大估计吸引域(largest estimated domain of attraction,LEDA),并将LEDA与基于LaSalle不变集定理的能量函数法和平方和规划法构建的LEDA进行详细对比,验证了所提方法在刻画LEDA方面具有更低的保守性。然后从保证故障穿越控制过程中的锁相环暂态同步稳定作为切入点,首次提出WG-VSC系统在电网对称故障大扰动下的有功/无功电流设定值可行域概念,并基于线性矩阵不等式方法刻画的LEDA,提出该可行域的求解算法,分析了典型参数对该电流设定值可行域的影响。该可行域为故障过程中的有功和无功电流设定值提供了切实可行的指导依据。最后在PSCAD/EMTDC中搭建了基于详细开关模型的WG-VSC系统仿真算例,通过多种暂态仿真工况验证了该文所构建的LEDA和电流设定值可行域的有效性和可行性。
