The low laser induced damage threshold of the KH2PO4 crystal seriously restricts the output power of inertial confinement fusion.The micro-waviness on the KH2PO4 surface processed by single point diamond turning has a...The low laser induced damage threshold of the KH2PO4 crystal seriously restricts the output power of inertial confinement fusion.The micro-waviness on the KH2PO4 surface processed by single point diamond turning has a significant influence on the damage threshold.In this paper,the influence of micro-waviness on the damage threshold of the KH2PO4 crystal and the chief sources introducing the micro-waviness are analysed based on the combination of the Fourier modal theory and the power spectrum density method.Research results indicate that among the sub-wavinesses with different characteristic spatial frequencies there exists the most dangerous frequency which greatly reduces the damage threshold,although it may not occupy the largest proportion in the original surface.The experimental damage threshold is basically consistent with the theoretical calculation.For the processing parameters used,the leading frequency of micro-waviness which causes the damage threshold to decrease is between 350-1 μm-1 and 30-1 μm-1,especially between 90-1 μm-1 and 200-1 μm-1.Based on the classification study of the time frequencies of microwaviness,we find that the axial vibration of the spindle is the chief source introducing the micro-waviness,nearly all the leading frequencies are related to the practical spindle frequency（about 6.68 Hz,400 r/min） and a special middle frequency（between 1.029 Hz and 1.143 Hz）.展开更多
为提高清洁能源利用率、降低高渗透率可再生能源型微网成本,基于分时电价背景,在综合考虑风电、光伏、燃气轮机、大电网联络线等多类型电源运行特性的基础上,以经济成本为目标,建立了冷热电联供(combined cooling,heating and power,CC...为提高清洁能源利用率、降低高渗透率可再生能源型微网成本,基于分时电价背景,在综合考虑风电、光伏、燃气轮机、大电网联络线等多类型电源运行特性的基础上,以经济成本为目标,建立了冷热电联供(combined cooling,heating and power,CCHP)型微网协同优化模型,同时提出一种结合粒子群思想、协同进化理论框架和天牛须搜索(beetle antennae search,BAS)算法的改进优化算法——CoPSO-BAS算法。该算法同时兼顾了BAS算法、协同进化算法与粒子群算法的优点,具有良好的全局最优解搜索能力与收敛性。以我国西北某微网系统作为实际算例,应用CoPSO-BAS算法进行计算,并与经典BAS算法对比,验证了CoPSO-BAS算法的全局最优解搜索能力和收敛性能上的优越性。展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 50875066)
文摘The low laser induced damage threshold of the KH2PO4 crystal seriously restricts the output power of inertial confinement fusion.The micro-waviness on the KH2PO4 surface processed by single point diamond turning has a significant influence on the damage threshold.In this paper,the influence of micro-waviness on the damage threshold of the KH2PO4 crystal and the chief sources introducing the micro-waviness are analysed based on the combination of the Fourier modal theory and the power spectrum density method.Research results indicate that among the sub-wavinesses with different characteristic spatial frequencies there exists the most dangerous frequency which greatly reduces the damage threshold,although it may not occupy the largest proportion in the original surface.The experimental damage threshold is basically consistent with the theoretical calculation.For the processing parameters used,the leading frequency of micro-waviness which causes the damage threshold to decrease is between 350-1 μm-1 and 30-1 μm-1,especially between 90-1 μm-1 and 200-1 μm-1.Based on the classification study of the time frequencies of microwaviness,we find that the axial vibration of the spindle is the chief source introducing the micro-waviness,nearly all the leading frequencies are related to the practical spindle frequency（about 6.68 Hz,400 r/min） and a special middle frequency（between 1.029 Hz and 1.143 Hz）.
