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61.
The solutions of the strongly nonlocal spatial solitons with several types of nonlocal response functions 总被引:3,自引:0,他引:3
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The fundamental and second order strongly nonlocal solitons of the
nonlocal nonlinear Schr\"{o}dinger equation for several types of
nonlocal responses are calculated by Ritz's variational method. For
a specific type of nonlocal response, the solutions of the strongly
nonlocal solitons with the same beam width but different degrees of
nonlocality are identical except for an amplitude factor. For a
nonlocal case where the nonlocal response function decays in direct
proportion to the $m$th power of the distance near the source point,
the power and the phase constant of the strongly nonlocal soliton are
in inverse proportion to the $(m+2)$th power of its beam width. 相似文献
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针对目前紫外光谱仪热工况优化研究缺乏的问题,该文设计出一款探测范围为200 nm~450 nm、全波段分辨率不低于0.2 nm的罗兰圆光谱仪,并耦合光、热、结构模拟对其光室热工况开展优化研究。热仿真结果表明:在无加热、无入口风速下光谱仪底座温度、温差随时间不断增加,难以达到热平衡;优化光室入口风速,发现当入口风速为0.8 m/s时,整体温度降至36.103℃~39.859℃;基于光学器件间的热变形量的计算,光学器件截距总热变形量为0.203 mm;优化加热方式,发现顶层式加热方式最佳,整体温度降至34.241℃~36.139℃,光学器件截距总热变形量降至0.122 mm。对此进行光学仿真,结果表明,优化工况后的罗兰圆光谱仪工作热变形后可清晰分辨出两束波长相差0.2 nm的光束。 相似文献
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多参数位移反分析优化设计与约束反演 总被引:7,自引:0,他引:7
针对岩土工程位移反分析,提出一般地应力场优化设计的数学形式,构造了岩层变形破坏的结构性计算模型。应用以有限元和约束优化为基础的正定式化方法进行了多参数约束反演,并编制了计算程序。通过地应力参数和岩层结构模量的数值反演算例,说明优化设计和约束反演能同时有效地识别多个参数,可提高反演可靠性和准确度,且能保障计算稳定性。 相似文献
66.
一种基于HHT的信号周期性分析方法及应用 总被引:3,自引:1,他引:2
提出了一种基于HHT(Hilbert-Huang Transform)的信号周期性分析方法,通过分析信号的非线性对主频分布的影响,找到了具有丰富高频含量的近似周期信号的主频与其周期性的近似对应关系,实验表明,根据信号的主频分布来估计信号的周期性具有很好的精确性.将其应用于自然纹理图像的分析,能很好地提取纹理图像的周期特征,为纹理分类、分割、识别和图像检索提供了新的解决途径. 相似文献
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Modification of spontaneous emission rate of micrometer-sized light sources using hollow-core photonic crystal fibers
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We investigate numerically and experimentally the modification of
the spontaneous emission rate for micrometer-sized light sources
embedded in a hollow-core photonic crystal fiber (HCPCF). The
diameter of the light source is deliberately chosen such that they
could be easily introduced into the central hole of the hollow-core
photonic crystal fiber by capillary force. The photoluminescence
from the microparticles is measured by using an inverted microscope
in combination with a spectrometer. The modification of the spontaneous
emission rate is observed in a wavelength region where there is no
band gap. The experimental observations are consistent with
the simulation results obtained by the plane wave expansion and
finite-difference time-domain techniques. 相似文献
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吴立军 《中国新技术新产品精选》2009,(12):22-23
GSM-R工程建设中频率规划意义重大,本文对三种常见GSM—R无线网络的组网方式的频率规划进行了研究。 相似文献