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分段压缩平面共腔条形激光器是为了适应日益增长的信息时代的需要,使器件具有低阈值、良好的线性输出和大功率单模工作等优良特性而研制的一种新结构半导体双异质结激光器.在本发明成功之前,国外已经研制出许多种结构类型的半导体双异质结激光器.从平行p-n结的侧向波导机制上分,该激光器大体可以分为增益导引和内建实折射率导引激光器两大类.早期研制的大多数是增益导引激光器.这类结构激光器的特点是有源区是平的、无厚度变化的.其优点是:工艺简单,空间侧向模式的选择性较好,易实现基侧向横模振荡;缺点是:缺少一个稳定的侧向模式导引机制,… 相似文献
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文章介绍了小粒子核磁共振研究的意义,样品的特点,Pt小粒子的NMR谱随分散度,表面处理等变化,Pt/氧化物小粒子样品的自旋-晶格弛豫呈现Korringa机制,而Pt/沸石小粒子样品出现依赖温度的金属-非金属转变,用小粒子的NMR得到局部态密度与表面吸附之间的关系,揭示出催化金属表面的LDOS很可能与多相催化中的“活性位”相联系。不久前对Rh小粒子的NMR研究,得到的谱与尺寸有关而与温度无关。 相似文献
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The production of a polarized 7Li atomic beam in a strong magnetic field was experimentally studied by laser optical pumping of a single ground hyperfine F level. It was shown that nearly complete negative and partial positive polarizations of 7Li atoms could be realized under appropriate conditions by this pumping scheme, which was in agreement with the rate equation calculations. Based on the analyses of transition probabilities, the maximum polarizations for various transitions and light polarizations were given. 相似文献
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