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自聚焦效应对激光内切割质量的影响
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作者 王安平 李正佳 任清荣 《激光杂志》 CAS CSCD 北大核心 2001年第6期68-70,共3页
本文介绍了一种新型RP技术—激光内切割技术。这种技术由于它自身的特性会引起光束在材料内部传输时产生自聚焦效应 ,从而影响激光内切割的切割质量。这种影响可以通过对数控程序中机床步距进行修正来削弱或者消除。
关键词 激光内切割 自聚集效应 步距 切割质量
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Nematicidal Effects of Azadirachta indica Seed Extract on Meloidogyne spp.
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作者 F. T. Gravanis I. K. Vagelas S. V. Leontopoulos D. Natsiopoulos 《Journal of Agricultural Science and Technology(A)》 2011年第1X期136-141,共6页
Root-Knot Nematodes (RKN) Meloidogyne spp. significantly affects glasshouse tomatoes in Central Greece. Elimination or halting J2s could be an efficient strategy to control RKN. Recently, it was reported that a comm... Root-Knot Nematodes (RKN) Meloidogyne spp. significantly affects glasshouse tomatoes in Central Greece. Elimination or halting J2s could be an efficient strategy to control RKN. Recently, it was reported that a commercial product of Neem (Azadirachta indica) seed extract (Azadirachtin 1% Emulsion Concentrate-EC) significantly reduced the number of galls on tomato roots and egg masses, compared to the untreated control. In the present study neem proved to have a direct immobilising effect on RKN J2s. Different concentrations (0, 0.05, 0,1, 0.25, 0.5, I, 5, 10, 25 and 50%) of the tested neem product were applied with water containing fresh J2s and in soil naturally infected with RKN. Records of immobilised J2s were taken after 10 min, 1 h, 6 h, 24 h and 72 h of Neem application in water and after six days of neem application into the soil. Neem solution concentrations 5% and 10%, resulted in 85% ± 3.2 and 100% of immobilised J2s. The same concentrations of neem when were added in the water for nematode extraction from the soil, resulted 14.25% ± 4.01 and 1.7%, of J2s extracted from the soil with a significant concentration effect (P = 0.008), compared to the untreated control. However, the neem product at high application dose significant damage the tomato plants caused phytoxicity. 展开更多
关键词 Azadirachta indica natural products botanical pesticides phytoparasitic nematodes BIOCONTROL
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对数型非线性电介质中的一维空间亮孤子 被引量:6
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作者 卫青 王奇 《光学学报》 EI CAS CSCD 北大核心 2003年第10期1172-1175,共4页
研究了对数型非线性电介质中空间亮孤子 ,认为对数型电介质中可支持亮空间孤子 ,并对其束宽变化作了分析 ,指出其束宽变化与光源峰值功率成反比 :当功率较低时 ,束宽随功率的增大而急剧减小 ,表现出良好的非线性效应 ;当功率不断增大时 ... 研究了对数型非线性电介质中空间亮孤子 ,认为对数型电介质中可支持亮空间孤子 ,并对其束宽变化作了分析 ,指出其束宽变化与光源峰值功率成反比 :当功率较低时 ,束宽随功率的增大而急剧减小 ,表现出良好的非线性效应 ;当功率不断增大时 ,束宽的减小趋势逐渐放慢直至停止 。 展开更多
关键词 对数型非线性电介质 一维空间亮孤子 束宽变化 非线性光学 自聚集效应 稳态分析法
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