共查询到20条相似文献，搜索用时 19 毫秒
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Kinematics in Finsler space is used to study the propagation of ultra high energy cosmic rays particles through the cosmic microwave background radiation. We find that the GZK threshold is lifted dramatically in Randers-Finsler space. A tiny deformation of spacetime from Minkowskian to Finslerian allows more ultra-high energy cosmic rays particles to arrive at the earth. It is suggested that the lower bound of particle mass is related with the negative second invariant speed in Randers-Finsler space. 相似文献
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Thermal fluctuations in angular momentum due to excitation is investigated. Shape changes or structural rearrangement are observed as a consequence of fluctuation in second moment of spin. The uncertainty in angular momentum is considerably enhanced due to thermal fluctuation and is strongly dependent on spin and structural changes. 相似文献
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光纤截止波长是单模光纤的一个重要参数，它与许多因素如模场直径、长度、弯曲、衰减等有关。本文分析研究与截止波长相关的这些因素后，指出在制造光纤光缆时要尽可能减少对光纤截止波长不利的因素，将最小工作波长提高到60－70nm作为设计光纤的截止波长上限，从而有利于降低光纤弯曲损耗。 相似文献
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用数值计算了 W型单模单偏振光纤基模截止归一化频率 ,分析了基模截止归一化频率与光纤结构参数的关系 ,得出了在外包层远离纤芯的情况下 ,基模截止归一化频率仅与内包层折射率深度有关 ,同时给出了其相应的近似函数关系和曲线 相似文献
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Muhammad Zahir Iqbal Jordi Prez‐Puigdemont Jonghwa Eom Nuria Ferrer‐Anglada 《physica status solidi b》2014,251(12):2461-2465
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George Svetlichny 《Foundations of Physics Letters》2004,17(2):197-202
We point out that the presence of energetic cosmic rays above the GZK cutoff may be explained by fundamental non-linearities in quantum mechanics at the Planck level. 相似文献
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本文研究了在耐酸不锈钢基体上采用激光熔覆和等离子喷焊二种工艺形成的涂层对耐腐蚀性的影响。使用５ｋＷ横流ＣＯ２激光器对预置在基体上的Ｃｏ基自熔合金粉末进行熔覆加工,得到的熔层与等离子焊层对比：激光熔层缺陷率低,被机体稀释率更小,成品率更高。其组织致密均匀,晶粒细小,熔层硬度与强韧性更高。性能试验证明：激光熔层有更好的耐腐蚀性能。 相似文献
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Jun Hu Qiang Li Shiyang Shao Lixiang Wang Xiabin Jing Fosong Wang 《Advanced Optical Materials》2020,8(11)
White‐emitting polymers hold great promise for the production of low‐cost and large‐area light sources via solution process. However, the development of efficient and stable white‐emitting polymers has been a formidable challenge yet. Here a strategy for single white‐emitting polymers is demonstrated with high efficiency, low roll‐off, and enhanced device stability by using through‐space charge transfer (TSCT) polymer with small singlet‐triplet energy splitting and blue thermally activated delayed fluorescence as host for yellow phosphor. This strategy not only combines delayed fluorescence and phosphorescence in one polymer to make full use of excitons but also enables the long‐range Förster resonant energy transfer from polymer host to phosphor for suppressing triplet quenching at high luminance, leading to state‐of‐the‐art luminous efficiency of 50.9 cd A−1 at 1000 cd m−2 (corresponding to a low roll‐off of 1.9%) for white‐emitting polymers, together with a tenfold increase in device lifetime over the control polymers based on a conventional polymer host. These results shed light on the prospect of using TSCT polymer with delayed fluorescence as host for developing efficient and stable white‐emitting polymers for solution‐processed white organic light‐emitting diodes. 相似文献
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基于Wolf近轴传输理论, 导出离轴径向偏振光束光强的解析表达式, 并研究离轴量对离轴径向偏振光束传输中光强分布的影响, 同时根据一阶矩质心位置的定义推导出离轴径向偏振光束的质心坐标, 研究其质心位置的变化规律. 结果表明, 与径向偏振光束不同, 离轴径向偏振光束在近场处传输时光强分布不均匀, 随着传输距离的增加, 光强分布均匀性逐渐得到改善, 而径向偏振光束在传输中始终保持空心对称光斑. 离轴量较小时, 近场处光强分布呈非对称空心面包圈形, 随着传输距离增达到一定程度, 光强分布演化为对称空心面包圈形, 离轴量越小, 演变距离越短; 离轴量较大时, 随着光束的传输离轴径向偏振光束的空心部分消失, 逐渐由空心面包圈形向高斯型演变, 径向偏振光束特性消失. 另一方面, 离轴径向偏振光束的质心不随传输距离的改变而改变. 质心纵坐标恒为零, 质心横坐标与光斑尺寸及离轴量相关. 随着光斑尺寸增大, 质心横坐标成线性增长. 当离轴量较小时, 质心横坐标随离轴量的增大呈非线性增长, 增长量不明显; 离轴量较大时, 质心横坐标随离轴量的增大呈线性增长, 且变化明显. 相似文献