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1.
光纤传感振动检测系统及其实验研究 总被引:3,自引:0,他引:3
实际工程结构中的振动检测是十分重要的,也是十分复杂的,常用的结构振动检测传感器易受工程现场恶劣环境的影响.而光纤传感器具有小巧、抗电磁干扰、灵敏度高、适合长期监测等优点。本文建立了基于马赫—曾德(Mech-Zehnder)干涉原理的光纤传感振动检测系统.研制了运用先进的数字信号处理技术采集和处理数据的专用软件,并在典型结构件——钢制悬臂梁结构上进行了外加信号作用下的强迫振动检测和冲击载荷作用下的自由衰减振动检测,测量了该结构件的频率及振幅,其结果与同时进行的成熟的电测结果相近,说明光纤传感器用于结构件的振动测量是可靠的。本文为光纤传感器应用于实际工程的振动检测提供了新的技术装置,具有工程应用前景。 相似文献
2.
A. Di Maio A. Rocco P. Ferraro M. De Rosa P. De Natale S. De Nicola A. Finizio G. Pierattini G. Coppola M. Iodice V. Striano 《Optics and Lasers in Engineering》2007,45(3):385
In view of the growing interest for non-destructive tests of materials, geodynamical monitoring and in general remote sensing, there is a great effort to bring practical optical sensors from research labs to industrial and environmental applications. In this paper, we employ digital holographic technique as an efficient tool for evaluating the strain measurement capability of fiber Bragg gratings (FBG). A cantilever beam has been employed as a test structure under loading test. The strain measurements results obtained by fiber-based sensors have been compared to those obtained by using full-field digital holographic technique and point-wise strain gauge sensors glued on the same cantilever beam. A simple theoretical model is also presented to interpret and compare the experimental results coming from different techniques. 相似文献
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CCD光谱谱线标定方法研究 总被引:9,自引:5,他引:4
CCD作为光谱分析和测色仪器的光谱接收器件 ,光谱谱线定位受单色仪狭缝和CCD光敏元尺寸影响。提出采用最小二乘法做曲线拟合和质心法来确定光谱线在CCD上的精确定位 ,使光谱谱线的定位精度得到提高 ,并且不受CCD光敏元尺寸限制。实验结果表明 ,两种方法对光谱线的定位 ,具有重复性高 ,稳定性好等特点。在定位精度上 ,两者具有一致性。 相似文献
5.
Dispersion Compensation in Externally Modulated Transmission System Using Chirped Fiber Grating 总被引:1,自引:0,他引:1
We present an externally modulated NTSC AM-VSB erbium-doped fiber amplifier (EDFA)-repeated system in the 1550 nm region which uses a chirped fiber grating (CFG) as a dispersion compensation device. In contrast to the conventional externally modulated fiber optical CATV systems, either with or without dispersion compensation fiber (DCF), good performances of carrier-to-noise ratio (CNR) ≥50 dB, composite second order (CSO) ≥74 dB, and composite triple beat (CTB) ≥65 dB were achieved for the full channel band after a 100-km single-mode fiber (SMF) transmission. 相似文献
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Daniel E. Vogler Ana Lorencak Julien M. Rey Markus W. Sigrist 《Optics and Lasers in Engineering》2005,43(3-5):527
A novel sensitive technique for the determination of losses in fiber cavities is presented. The method is based on the cavity ringdown scheme implemented in silica-based single-mode fibers. Bending losses of fiber cavities of different lengths have been measured showing all an oscillating behavior with respect to the curvature radius of the fiber as predicted by a theoretical model. The best minimum detectable absorbance per cavity pass achieved by this new method is 1.72×10−3 dB within a 10 m-long cavity. This limit suffices well for an accurate determination of optical bending losses even in bend-insensitive fibers. Furthermore, the comparison of the measured bending losses with a theoretical model allows the extraction of different fiber parameters. Good agreement has been found between the experimentally derived parameters and literature data. 相似文献
8.
The analysis of a demodulation system for Fiber Bragg Grating sensors based on two fixed spectral filters has been carried out both theoretically and experimentally. Different system configurations were analyzed by modifying the spectral position of the filters as well as the optical power-level of the signal reaching the two photo-detectors. Measurements with integration times that varied from 0.01 to 1 s have been compared with the low-frequency limit predicted for long-term operation. Comparisons between simulated and experimental results show good agreement, and extrapolations indicate that it should be possible to achieve an operating spectrum range of the order of 7 nm, with uncertainties equivalent to less than 2 pm in measurements of the sensor peak position. 相似文献
9.
Michael Binnewies Marion Jerzembeck Andreas Kornick 《Angewandte Chemie (International ed. in English)》1991,30(7):745-753
One of the modern high technologies which has advanced enormously in the last few years is glass fiber technology. This is used in the manufacture of glass fibers for lighting purposes and for the optical transfer of analog and digital data with a high transfer density. The technical demands made on the glass fibers required for data transfer, the optical waveguides, are extremely high and are already fulfilled to a large extent by industry. At present about four million kilometers of fiber, worth ca. 800 million DM are produced worldwide (10% in the Federal Republic of Germany). Numerous chemical processes take place during the manufacture of optical waveguides. However, in contrast both to the high and constantly growing demands on the quality and to the increasing production volume of such fibers, little is in fact known about the reactions involved. The present article will attempt to develop a picture of the multifarious reactions occurring in the course of this technical process on the basis of literature data and our own studies. 相似文献
10.
The aim of this work was to investigate, for the first time, the potential of the enzyme glutathione S-transferase I (isoenzyme GST-I) for uses in analytical chemistry. A novel fiber-optic biosensor for the detection and determination of the triazine herbicide atrazine was developed based on maize GST-I expressed in E. coli. The sensing bioactive material was a three-layer mini-sandwich. The enzyme was immobilized on the outer layer that consisted of a hydrophilic polyvinylidenefluoride membrane. This membrane was supported on an inner glass disk by means of an intermediate binder sol–gel layer that incorporated bromcresol green (BCG). The biosensor operated in a static mode at 25 °C and the rate of the enzymatic reaction, using atrazine as a substrate, served as an analytical signal. A calibration curve was obtained for atrazine, with analytically useful concentration range 2.52–125 μM. The sensor detection limit was 0.84 μM. The reproducibility of atrazine sensing was in the order of ±3–5%. The method was successfully applied to the determination of this herbicide in real water samples, without sample preparation steps. Atrazine recovery ranged between 85 and 110%. No interference from other pesticides, such as alachlor and carbaryl was observed in the absence of atrazine. The immobilized enzyme retained about 75% of its original activity after 1 month use. Simply unscrewing the terminal holding ring of the probe and placing a new bioactive sandwich could easily replace a deteriorated mini-sandwich. 相似文献