Results 81 to 90 of about 2,130 (150)
Guangtongxin yanjiu, 2016 为了探究延长光纤机械寿命的关键技术,研究了光纤机械可靠性及寿命评估模型。影响光纤机械寿命的主要因素是光纤裂纹生成和光纤裂纹在应力腐蚀下不断生长。根据光纤机械强度计算公式以及光纤疲劳试验的威布尔分布特性,建立光纤筛选实验寿命评估模型。运用该寿命评估模型对OPGW（光纤复合架空地线）线路寿命进行模拟计算和评估,探究了延长OPGW线路寿命的关键技术。结果表明,提高光纤疲劳参数和降低光纤使用时的应力水平,均可显著提高光纤寿命。
陈黎明, 刘骋, 侯继勇, 冯学斌
doaj
Multi-Robot exploration for coal mine rescue based on the extension of undirected graph [PDF]
After coal mine disasters, the environment deteriorates and rescue tasks are complex and arduous, resulting in numerous threats to the rescue personnel.
Chunyu YANG +4 more
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Guangtongxin yanjiu, 2017 通过实验实现了一个2 000km的16阶正交振幅调制传输系统,该系统采用后向分布式拉曼放大器对信号进行放大,单段跨距为80km,并在接收端采用数字背向传输算法补偿光纤传输过程中的非线性效应。采用分布式拉曼放大后,信号在光纤中的功率分布不再是指数衰减,采用的数字背向传输算法对此做了优化。实验结果表明,采用数字背向传输算法后,信号的Q2值提升了2.1dB。
邓沌华, 郑强, 李蔚
doaj
Fracture structure of the overburden in the layered mining of extremely thick coal seams: Developmental patterns of caving zones and hydraulically conductive fracture zones and fracture characteristics [PDF]
ObjectiveThe Zhunnan Coalfield, a coalfield on the southern margin of the Junggar Basin in Xinjiang, boasts abundant coal resources. However, water hazards in mines severely constrain the safe and efficient coal production in the coalfield.
Hailun MENG +8 more
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Guangtongxin yanjiu, 1989 本文通过平均光纤材料双折射分布,导出了计算bow—tie和Panda光纤双折射和偏振模色散的近似表达式。本文结果与有限元得到的结果吻合得非常好。
陈智浩, 瞿燕, 姚慧海
doaj
Analysis of spatiotemporal evolution characteristics of floor rock mass and roadway failure under mining influence [PDF]
Clarifying the distribution law of mining induced stress in the working face floor, achieving precise grasp of the degree of damage to the floor rock mass and roadway under the influence of mining, can effectively prevent deformation and instability of ...
Baojie FU +4 more
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Guangtongxin yanjiu, 2017 为了实现每基杆塔的光纤定位,从而更精准地实时监测光纤架空地线复合缆的运行状态,提出了一种基于分布式光纤传感技术的杆塔光纤定位方法。通过对实时监测频移数据进行分析,并结合光纤架空地线复合缆自身结构和架设特点发现,在杆塔连接位置由于金具等的连接原因,使得光纤频移变化量较档距中间更小,因而可以从差异化出发识别杆塔的位置,实现输电线路杆塔精确定位。最后通过与线路资料进行对比,验证了定位方式的可行性。
黄良 +6 more
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Coal burst risk monitoring method based on the drilling powder of destressing drilling in coal seam and its application [PDF]
The drilling powder monitoring method is one commonly used method for coal burst risk evaluation in coal mines. The construction method of large-diameter destressing drilling is similar to that of the drilling powder monitoring method.
Jiuguo GAO +5 more
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Dianci bileiqi, 2018 电位分布及温度分布情况是对避雷器健康运行进行评价的重要指标,直接关系到整支避雷器的运行寿命,在无均压措施的情况下,将导致老化速度加快,甚至发生热崩溃。对避雷器的电位分布情况进行测试是对避雷器进行均压的首要条件,但传统检测手段均为基于有线光纤方式进行电位分布采集。本项目基于高性能AVR微处理器,便携式单片微型计算机采样,无线通信,同步采样分析等手段,成功研制了避雷器电位分布及温度分布无线检测系统。对避雷器电位分布及温度分布情况以无线同步方式进行测试,避免了测试现场繁琐的光纤布线 ...
李佳奇 +5 more
doaj
Characteristics and mechanism of overlying rock and surface damage in gently inclined thick coal seam mining [PDF]
In order to scientifically guide the disaster prevention and ecological environment protection of the gently coal seam mining in the west of Ordos Basin, and to realize the green and safe mining of coal.
Bingchao ZHAO +5 more
core +1 more source