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化学文献检索课八年教学回顾 总被引:1,自引:0,他引:1
化学文献检索课八年教学回顾杨洪武,吴庆安,杨素勤(郑州大学化学系河南450052)国家教委1992年下发教高司44号文件,提出“文献检索课教学的基本要求”,旨在增强学生的情报意识、改善知识结构、提高自学和科研能力。根据文件精神,我们对八年来化学文献检... 相似文献
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We design and analyze a novel multiband left-handed metamaterial based on a fishnet-like structure at terahertz (THz) frequencies.The metamaterial exhibits simultaneous negative refractions around the frequencies of 0.48,1.05,and 1.19 THz for the electromagnetic (EM) wave normal incidence,and around the frequencies of 0.20,0.79,and 1.13 THz for parallel incidence.The simulated results verify the left-handed properties.A particularly important observation is the capability of the proposed metamaterial with a single geometrical structure to display multifrequency operations in a unit cell.The compact metamaterial is a major step toward the miniaturization of THz materials and devices suitable for multifrequencies. 相似文献
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