共查询到19条相似文献,搜索用时 125 毫秒
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介绍采用光纤波分耦合器解调技术的全光纤FBG应变传感器可检测应变范围100με时动态分辨牢达0.5με/√H,静态分辨率达1με.采用强耦合型光纤波分耦合器,则性能还可进一步提高.光纤熔融拉锥工艺强耦合技术业已成熟,为本方案的实现打下坚实基础.此方案的优点是全光纤型,能量损耗低、结构紧凑、测量精度较高、成本低、性价比好、有竞争力,可满足一般工程应用,其发展前途值得注意. 相似文献
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耦合腔半导体激光器具有频率调制特性,本文根据这一原理,讨论了利用外差检测技术的Michelson型光纤应变测量原理及方法.该方法避免了一般干涉型光纤传感器存在的位相正交问题,可实现大动态范围高精度的应变测量. 相似文献
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耦合腔半导体激光器具有频率调制特性,本文根据这一原理,讨论了利用外差检测技术的Michelson型光纤应变测量原理及方法。该方法避免了一般干涉型光纤传感器存在的位相正交问题,可实现大动态范围高精度的应变测量。 相似文献
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设计了一种由封闭在光纤内的纺锤型空气腔和其周围的SiO2构成的三明治结构全光纤马赫-曾德尔干涉仪,并将其用于应变传感.纺锤型空气腔利用光子晶体光纤和普通单模光纤熔接后再拉锥形成.由于干涉仪的两个干涉臂介质为空气和SiO2,因此超短的干涉臂长使光传输损耗大大降低,构成了超紧凑马赫-曾德尔干涉仪.该干涉仪用于应变传感可大大减小弯曲带来的串扰,提高系统的稳定性.建立了超紧凑马赫-曾德尔干涉仪模型,基于FDTD算法对干涉仪输出的干涉条纹以及各部分的电场分布进行了仿真,得到了应变传感器干涉条纹波谷波长与应变的关系,为设计制作超紧凑全光纤马赫-曾德尔应变传感器提供了理论依据. 相似文献
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目的探讨肝癌患者血清瘦素(Leptin)的变化及其意义。方法研究分肝癌组(104例)、肝癌术后组(86例)及正常对照组(100例),采用全自动生化分析仪检测各组血清中总胆固醇(TC)、甘油三酯(TG)、碱性磷酸酶(ALP)及总胆红素(STB)等生化指标并用放射免疫法检测Leptin及甲胎蛋白(AFP)。结果与正常对照组相比,肝癌组血清TG、TC、ALP、STB、Leptin、AFP及肝癌术后组TG、Leptin、AFP含量均显著升高(P〈0.05),同时与肝癌组相比,肝癌术后组Leptin、AFP含量明显降低(P〈O.05),TC、TG、ALP、STB含量无明显改变。Leptin与TC、TG呈正相关,而与AFP、ALP、STB无相关性。结论Leptin参与肝癌的发生发展,其作用机制可能与促进肝癌组织新生血管形成有关。 相似文献
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激光脉冲制作的长周期光纤光栅/法布里-珀罗高温-应变组合传感器 总被引:2,自引:2,他引:2
在很多高温环境应用中,诸如发动机、飞机和宇航器、复合材料的健康监测,需要精确测量应变。针对这种场合提出了一种基于激光脉冲制作的长周期光纤光栅/法布里-珀罗(LPFG/F-P)温度-应变组合光纤传感器。该传感器由长周期光纤光栅与光纤法布里-珀罗干涉传感器级联构成,其中长周期光纤光栅由高频CO2激光脉冲制作,用于监测温度;光纤法布里-珀罗干涉传感器由157nm准分子激光脉冲制作,用于监测应变。这种新型组合光纤传感器最大的特点是能承受500℃的高温并能在高温环境下实现应变的精确测量,可望在高温恶劣环境条件下的结构(如飞机发动机)健康监测、复合材料生产过程监测等应用中发挥重要作用。 相似文献
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相位压缩技术在光纤应变传感器中的应用 总被引:1,自引:1,他引:0
介绍了相位压缩技术在光纤应变传感器中的应用,对其工作原理进行了分析,给出了数学模型,并进行了实验研究。理论分析及实验表明。与普通干涉仪相比该系统的动态测量范围扩大了数百倍,并且系统不受外界缓变量的影响;该系统的线性度为0.18%,精度为0.17%。 相似文献
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Materials with structurally integrated fiber-optic sensors, the first step toward smart structures, which continuously monitor their own vibration, internal strain and deformation, temperature, and structural integrity are described. It is shown that the Fabry-Perot fiber-optic strain sensor has capabilities that far exceed those of conventional foil strain gauges, which holds the promise of responding to acoustic emission signals while simultaneously tracking the high loads likely to be encountered in practical structures such as aircraft wings. The same sensing system may be able to monitor the degree of cure during fabrication of thermoset composite structures. The fabrication and characterization of such all-fiber, intrinsic Fabry-Perot strain sensors are discussed. Passive and active homodyne signal recovery techniques used in the fiber-optic sensor systems are also described 相似文献
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Jianzhong Zhang Peng G.D. Libo Yuan Weimin Sun Wencai Jin 《Photonics Technology Letters, IEEE》2007,19(14):1084-1086
A novel fiber-optic sensor unit by combining fiber-optic white-light interferometry and fiber Bragg gratings is proposed for simultaneous long- and short-gauge strain measurements. A new demodulation scheme based on spectral coherence theory for fiber-optic white-light interferometric sensors is proposed. This makes it possible that two quite different types of sensors in one unit can be simultaneously demodulated in the spectral domain. An experimental sensor unit has been built and tested. The results demonstrated that the spectral demodulation of the sensor unit is readily realized and that the sensor scheme is feasible. 相似文献
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结合波纹膜片的压力敏感特性和光纤Bragg光栅(FBG)的应变传感特性,设计了一种新型的FBG渗压传感器。传感器通过拉杆式结构将波纹膜片在应力下的挠度变形转化为FBG的轴向应变,通过恒温条件下的压强标定试验,得出传感器的压强灵敏度约为20 nm/MPa,和普通光栅相比,其压强灵敏度提高了6 000多倍。对传感器探头内部的光栅进行了温度特性标定试验,通过温度补偿光栅消除外界温度对渗压测量结果的影响。将该传感器用于隧道涌水模型的开挖试验,测得模型注水过程中测点的渗压值不断增大并趋于稳定,隧道开挖过程中渗压值轻微波动,提升水位时渗压值急剧增大。 相似文献
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宽带光纤/4波片是一种特殊的变速旋转型双折射光纤。当其旋转速度由小到大逐渐增加时,可将输入的线偏振光转换为圆偏振光,同时具有理想的偏振变换带宽。结合全光纤电流互感器的光路模型,分析了宽带光纤/4波片的特性对互感器标度因数稳定性的影响。通过在邦加球上的轨迹,对宽带光纤波片快转端的本征态及两正交本征态间的耦合系数进行了实验研究,测量了其随温度的变化。实验结果表明,当波片转速变化曲线满足一定条件时,宽带光纤/4波片的温度效应对电流互感器标度因数稳定性的影响小于0.2%,远小于窄带光纤/4波片的影响。利用宽带光纤/4波片可有效提高光纤电流互感器系统的温度稳定性。 相似文献
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Xiaoyi Bao DeMerchant M. Brown A. Bremner T. 《Lightwave Technology, Journal of》2001,19(11):1698-1704
The structural strain measurement of tension and compression in the steel beam was demonstrated with a distributed fiber-optic sensor system based on Brillouin scattering. The experiments were conducted both in the laboratory and outdoors. When it is in the outdoor environment, the temperature compensation has been taken into account for the strain measurement due to sunlight radiation. The compressive strain has been measured, without needing pretension on the fiber with a Brillouin scattering-based distributed sensor system, when the fiber is glued to the steel beam at every point. The dynamic range in the strain measurement has been increased, due to the elimination of the pretension requirement. The spatial resolution of the strain measurement is 0.5 m. The strain measurement accuracy is ±10 με(μm/m) in the laboratory environment with nonuniform-distributed strain. With uniform strain distribution, the strain accuracy for this system can be. ~±5 με. These results were achieved with the introductions of a computer-controlled polarization controller, a fast digitizer-signal averager, a pulse duration control, and the electrical optical modulator bias setting in the software 相似文献