Results 21 to 30 of about 2,130 (150)
Guangtongxin yanjiu, 2014 为了确定多模光纤布里渊频移的取值范围,进而评价多模光纤布里渊分布式传感系统的性能,从多模光纤的结构出发,根据射线光学理论分析了多模光纤中的布里渊散射过程,提出了确定布里渊散射角取值范围的方法,得到了阶跃型和渐变型多模光纤布里渊散射角的取值范围为两倍的全反射临界角到π,进而得到布里渊频移的变化范围为10.97811.083GHz,该结论为多模光纤布里渊分布式传感系统的设计和优化提供了理论依据。
李永倩, 赵旭, 赵丽娟
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Guangtongxin yanjiu, 2016 以实现柱矢量光横向选模为目标,研究了非均匀折射率分布的少模光纤的光学特性。利用有限元法分析了U型折射率分布和弯曲少模光纤的模场特性:前者结合1 550nm泵浦光可支持LP11模式并抑制LP01模式;后者包括二模光纤和四模光纤,当二者弯曲半径分别为4和2cm时,仅支持LP01和LP11模式。结合理论和实验研究了四模和二模FBG（光纤布拉格光栅）,对于二模FBG,当透射波长位于1 549.79nm附近时,可获得呈两瓣分布的LP11模式;对于四模FBG,其反射谱峰值波长个数随尾纤弯曲半径的减小而减少 ...
李宏业 +4 more
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Internal deformation characteristics and full section monitoring for extremely thick loose layers under mining conditions [PDF]
Mining subsidence represents the primary environmental geological challenge in coal mining, particularly at high water level mining areas in the eastern regions of China.
Pingsong ZHANG +3 more
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Guangtongxin yanjiu, 2011 基于光中继传感技术提出一种超远程分布式光纤拉曼温度传感器方案,采用在分布式光纤传感器的多段传感光缆之间嵌入多级光中继放大传感装置的方式,利用中继放大传感装置的增益克服光纤损耗,增强了光纤中自发拉曼散射光的强度,传感光缆分段分时进行测量。当在多段传感光缆之间引入N个远程光中继放大传感装置进行级联时,可实现分布式光纤传感器的N×L（L为每段传感光纤的长度）超远程监测。文章最后给出了实际测量结果,结果表明,该系统能在60 km的传感探测长度上获取具有较高信噪比的传感信号。
杨斌 +4 more
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Review on idler fault diagnosis and coordinated control in belt conveyors [PDF]
As a critical component of belt conveyors, idlers are prone to frequent failures, significantly impacting the efficiency and safety of coal mine operations.
BAO Jianjun +6 more
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Research on key architecture and model of coal mine water hazard intelligent early warning system [PDF]
, 2023 In order to ensure the safe production of mine threatened by water hazard, speed up the intelligent process of mine water hazard prediction and early warning technology, and improve the effect of mine water hazard prediction and early warning, based on ...
Hao QIU +5 more
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Guangtongxin yanjiu, 2009 文章作者在对光纤背向喇曼散射温度效应进行理论分析的基础上,对基于反斯托克斯/斯托克斯散射光强比值型的光纤分布式喇曼温度传感系统作了详细的研究,对系统主要器件的要求进行了计算,研制了基于单模光纤的5 km分布式温度传感器。实验表明,系统能精确地进行分布式测温,温度分辨率为1℃,空间分辨率为2 m。
国兵, 牟志华, 姜明顺, 隋青美
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, 2011 采用电聚合过氧化聚吡咯(Ox-PPy)于铅笔芯电极(PGE),并将酞菁钴(CoPc)对其修饰,制作了一种新型无酶电流型葡萄糖生物传感器。实验结果表明:在优化条件下,传感器的灵敏度为6.42μA/(mmol/L),线性范围0～10 mmol/L,线性相关度R=0.992 9,响应时间小于10 s,最低检测限为70.1μmol/L.该传感器具有较高的灵敏度 ...
林丞 +4 more
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A review of underground coal fire detection technology and engineering application [PDF]
Underground coal fires have a serious impact on coal resources and the environment, and the accurate detection of the location of fire areas is the premise and key to carrying out coal fire control. Based on the formation process of coal fire, this paper
CAO Shilong +3 more
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Zhendong Ceshi yu Zhenduan为了提高分布式光纤传感器监测结构动态响应的精度并提高损伤诊断的准确性，运用长短期记忆神经网络，建立布里渊增益谱‑频率数据关系模型，确定布里渊光时域分析技术中振幅传输模式扫描的固定频率。基于分布式光纤振动传感信息沿光纤密集分布特点，通过计算应变传递率梯度，提出了基于分布式动应变传递率梯度的损伤指标。不同损伤程度的悬臂梁分布式光纤振动传感实验表明，该方法能够实现结构损伤位置的诊断，且对毫米级裂纹仍有较强的敏感性。
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