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分别利用速率方程理论和六温度模型理论对Q开关CO2 激光器动力学过程进行了理论分析比较 ,实验上测得电光调Q射频波导CO2 激光器脉冲激光建立时间及峰值功率与速率方程理论和六温度模型理论计算结果一致 .但速率方程理论计算的激光脉冲宽度较“窄” ,并且几乎没有拖尾 ,而六温度模型理论计算的脉冲激光波形有明显的拖尾 ,符合实际测量的波形 .另外 ,六温度模型理论可以全面反映激光器工作气体中不同分子能级的能量转移过程 ,因此六温度模型理论分析更全面 相似文献
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在综述相关国际文献的基础上,通过对化学教育研究与化学研究、一般教育研究、其他化学教育活动的辨析,讨论了化学教育研究的特征、化学教育研究者的专业要求以及化学教育研究设计在理论基础、研究问题和研究方法等方面所应遵循的基本规范,以期提高对化学教育研究的认识,提升我国化学教育研究的科学化水平,促进化学教育研究领域的发展。 相似文献
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通过银促进的傅-克反应可以合成系列C3α-位为不同类型芳基取代的四氢吡咯并吲哚骨架的类天然产物.在该合成方法的基础上,发现C3α-位分别为对乙酰氨基苯基取代和甲基吲哚取代的四氢吡咯并吲哚类衍生物3a和3b对多种肿瘤细胞均表现出微摩尔级的活性,是具有重要临床应用前景的药物候选化合物.为了进一步研究该类化合物的成药性及其构效关系,以化合物3a为前体化合物合成了一系列类天然产物(化合物4~17),对其抗肿瘤活性进行了研究,并初步探讨了其构效关系.所合成化合物的结构经1H NMR、13C NMR和HRMS分析确证.本研究为该类化合物的临床前研究奠定了基础. 相似文献
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Ho and Ti co-doped BiFe03 multiferroic ceramics with enhanced magnetization and ultrahigh electrical resistivity 下载免费PDF全文
Bio.9HOo.lFeo.9503 and Bio.9HOo.lFeo.9Tio.0503 ceramics were prepared and compared to reveal the effects of Ho and Ti codoping in BiFeO3. X-ray diffraction indicated that both ceramics had a high rhombohedral perovskite phase content, and microstructural analyses showed that the grains of the Bio.9HOo.lFeo.9Tio.0503 ceramics were much smaller than those of Bio.9HOo.lFeo.9503. An electrical resistivity of more than 1 × 1014.cm at room temperature, and a magnetic hysteresis loop with a remnant magnetization 2Mr of 0.485 emu/g were obtained for Bi0.9HO0.1Fe0.9Ti0.0503; both were much higher than those of Bio.9Hoo.1Feo.9503. Changes in the defect subsystem of BiFeO3 induced by Fe-deficiency and (Ho,Ti) codoping are proposed as being responsible for the improvement in the properties. 相似文献
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Ho and Ti co-doped BiFeO_3 multiferroic ceramics with enhanced magnetization and ultrahigh electrical resistivity 下载免费PDF全文
Bi0.9Ho0.1Fe0.95O3 and Bi0.9Ho0.1Fe0.9Ti0.05O3 ceramics were prepared and compared to reveal the effects of Ho and Ti codoping in BiFeO3. X-ray diffraction indicated that both ceramics had a high rhombohedral perovskite phase content, and microstructural analyses showed that the grains of the Bi0.9Ho0.1Fe0.9Ti0.05O3 ceramics were much smaller than those of Bi0.9Ho0.1Fe0.95O3. An electrical resistivity of more than 1 × 1014?·cm at room temperature, and a magnetic hysteresis loop with a remnant magnetization 2Mr of ~ 0.485 emu/g were obtained for Bi0.9Ho0.1Fe0.9Ti0.05O3; both were much higher than those of Bi0.9Ho0.1Fe0.95O3. Changes in the defect subsystem of BiFeO3 induced by Fe-deficiency and(Ho,Ti) codoping are proposed as being responsible for the improvement in the properties. 相似文献
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为了解决靶场姿态测量系统中远距离单站测量易出现不稳定解或解不收敛的难题,从而为靶场常规中远距离光学单站姿态处理提供可行方案,在某参与计算特征点物距可获取的前提下,提出了一种物距辅助的单站姿态信息获取方法;首先提出物面连续离散化等效计算像长的方法,在此基础上,以像长为匹配元素建立单站透视姿态测量模型,然后以炮管为例对算法进行试验验证,最后对关键影响因素进行误差分析。结果表明:偏航角、俯仰角相对真值的均方根误差分别为0.97°、0.90°;所提方法可拓展至飞机类非轴对称回转体目标单站飞行姿态的处理。 相似文献
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