Fiber optic humidity sensors for high-energy physics applications at CERN

This work is devoted to a feasibility analysis for the development of novel fiber optic humidity sensors to be applied in high-energy physics (HEP) applications and in particular in experiments actually running at the European Organization for Nuclear Research (CERN). On this line of argument and due to the wide investigations carried out in the last years aimed to assess the radiation hardness capability of fiber optic technology in high energy physics environments, our multidisciplinary research group has been recently engaged in the development of near-field fiber optic sensors based on particle layers of tin dioxide to perform the monitoring of low values of relative humidity RH even at low temperatures.While this sensor type has been successfully employed for ppm and sub-ppm chemical detection in air and water environments, it is the first reported use for relative humidity measurements.The RH sensing performance of fabricated probes was analyzed during a deep experimental campaign carried out in the laboratories of CERN, in Genève. A very good agreement was observed between humidity measurements provided by the optical fiber sensors and commercial polymer-based hygrometers at 20 °C and 0 °C, with limits of detection for low RH regimes below 0.1%.     

光纤微弯传感器技术的发展与应用研究

光纤微弯传感器是一种强度调制型光纤传感器,通过光纤微弯曲导致传输光强度的损耗变化,来测量压力、温度、加速度、应变、流量、速度等环境参量;介绍了光纤微弯传感器的工作原理和特点,并详细论述了国内外光纤微弯传感器技术的发展与应用,最后,分析了光纤微弯传感器存在的局限性。     

光纤化学pH 传感技术的现状和进展

本文综述了光纤化学 pH传感器的现状和发展 .分别从 pH指示剂的试剂固定化方法和传感信号的产生与检测方式来阐述近年来光纤化学pH传感器新技术的发展 ;同时也介绍了其他 pH传感器的发展现状 .     

光纤微弯传感器研究

本文阐述了光纤微弯损耗机理和光纤微弯传感器的工作机理,并在此基础上提出了光纤微弯应变传感器系统设计模型。     

光纤瓦斯气体传感器评述—现状与未来

用于检测瓦斯浓度的光纤气体传感器在采矿、化工、石油和很多其它工业中,尤其在恶劣和危险的环境中具有广阔的应用前景。本文综述了光纤瓦斯气体传感器领域的近期发展。     

两种典型的光纤传感器研究现状与发展趋势

介绍了两种典型光纤传感器的研究和应用情况,提出了光纤传感器存在的问题及发展方向,为光纤传感器的深入研究提供了有益参考。     

外接光纤传感器应用于碳纤维智能复合材料结构的研究

在碳纤维复合材料结构的固化过程中,埋入其中的光纤将承受恶劣的环境,这将影响碳纤维智能复合材料结构中光纤传感系统的性能,并使光纤容易发生断裂。为解决这一问题,本文对几种外接式光纤传感器进行了初步探讨,并对外接式干涉光纤传感器进行了试验。结果表明外接式干涉光纤传感器可以完成检测碳纤维复合材料结构内部应变的任务,并能避免结构内光纤断裂造成传感器的失效,降低智能结构的制作成本,对智能结构的发展具有一定的促进作用。     

Tapered plastic multimode fiber sensor for salinity detection

A simple tapered plastic multimode (PMM) fiber optic sensor is proposed and demonstrated for continuous monitoring of salinity based on different concentration of sodium chloride (NaCl) in de-ionized water. The working mechanism of such device is based on the observed increment in the transmission of the sensor that is immersed in sodium chloride solution of higher concentration which also reflects an increase in its refractive index. The tapered PMM fiber is fabricated using heat-pulling method to achieve a waist diameter and a length of 0.187 mm and 5 mm, respectively. As the solution concentration varies from 0% to 12%, the output voltage of the sensor increases linearly from 0.109 mV to 1.142 mV with a sensitivity of 0.0024 mV/% and a linearity of more than 98%. The main advantages of this sensor are the feasibility of using PMM fiber which makes the sensor tougher, easier to fabricate and handle.     

地震微观前兆预报网络系统设计研究(4)——网络系统设计

提出了地震微观前兆预报网络系统设计的一整套详细方案,包括地震模型、基岩传感器网络和数据融合、信号处理技术和网络系统设计.本文介绍网络系统设计方案,包括光纤传感器在地震预报网络中的应用、传感器网络平台的选择和网络设计、地震源定位的相干声阵列处理技术、光数据通信技术.     

集成光路－光纤传感器及其进展

多功能集成光路技术与光纤传感器相结合，代表了光纤传感技术的一个重要发展方向。本文介绍集成光路在光纤陀螺、电场传感器、压力传感器和振动传感器等方面的应用及其进展。     

Development of silver nanorod array based fiber optic probes for SERS detection

The development of intrinsic SERS fiber optic sensors, i.e., fiber optical sensors that also serve as SERS active platforms, is challenging in that an easy, robust method that integrates the SERS active platform with fiber optics is still largely missing. There is a trade-off between implementing optimal morphology of SERS active nanostructures for best enhancement effect and preserving optical transparency that allows maximum transmission of the excitation radiation and the detected signals. In the present work, highly sensitive and reproducible silver nanorod arrays (AgNRs) have been integrated to a fiber optic probe for SERS detection. The films underlying the AgNR coating have been tailored to allow maximum light transmission while maintaining optimal SERS activity. The intense spectral background from the probe fiber core is largely eliminated by using a GRIN lens to produce a tight focus of the incident radiation at the AgNR coating. The performance of the AgNR fiber optic probes has been evaluated in a forward scattering optical configuration using BPE and adenine. The low detection limit of BPE and adenine is 10⁻⁷ M. Reproducibility and sampling methods are also discussed.     

Gas sensing properties of a clad modified fiber optic sensor with Ce, Li and Al doped nanocrystalline zinc oxides

Spectral characteristics of a clad modified fiber optic gas sensor are studied for various concentrations (0-500 ppm) of ammonia, methanol and ethanol at room temperature. Cerium, aluminum and lithium doped (6 at.%) nanocrystalline zinc oxides are replaced with a clad and used as gas sensing materials. The study shows that the spectral intensity increases linearly with concentration for ammonia whereas it decreases for methanol and ethanol. The Ce doped ZnO exhibits higher gas sensitivity compared to Al and Li doped zinc oxides. The time response of the sensor is presented for a Ce doped ZnO with ammonia gas. A model is proposed for understanding the spectral intensity variations.     

Mathematical models for assessment of the safety of steel beams based on average strains from long gage optic sensors

Most fiber optic sensors are point sensors that can measure the strain only at a local point of a beam, although strain distribution is non-uniform along the length of a beam. Long gage fiber optic sensors that measure integrated strain over a relatively long length can consider strain variation. This type of sensor was found to be efficient and useful for monitoring large-scale structures. On the other hand, the maximum strain in a beam cannot be measured with long gage optic sensors; the safety of a steel beam is analyzed by a comparison between the maximum stress measured during monitoring and the allowable stress of the beam calculated by a design code. Therefore, in this paper, simple mathematical models are presented for the determination of the maximum values of strains or stresses in a beam based on the average strains measured by long gage optic sensors. The model was tested in an experiment by comparing the maximum strain directly obtained from electrical gages and the calculated maximum strain from long gage optic sensors.     

集成光路－光纤传感器及其进展

多功能集成光路技术与光纤传感器相结合，代表了光纤传感技术的一个重要发展方向。本文介绍集成光路在光纤陀螺、电场传感器、压力传感器和振动传感器等方面的应用及其进展。     

Real-time measurement of multipoint hetero-core fiber optic binary sensors based on optical pulse loss change

Hetero-core fiber optic sensors can transmit sensing and communication signals on a single fiber optic transmission line and have numerous advantages for environmental information monitoring such as home security. Moreover, these sensors are cost effective due to their temperature independence and light-intensity-based measurements. We have previously developed a hetero-core fiber optic binary sensor that can be connected in series to detect the number of doors and windows that are opened or closed. In this paper, we propose an improved method for using hetero-core fiber optic binary sensors that are connected in series, which are referred to as binary switches. A unique pulse loss change enables the states of the connected switches to be identified. As a result, the total optical loss in the transmission line is reduced. Therefore, the number of binary switches connected in series can be increased on a single transmission line. The unique pulse loss peaks can be controlled by the action of a flat spring and by adjusting the position of the flat spring inside the binary switch module. Typical pulse peaks of each binary switch are from 0.13 to 0.75 dB in the positive direction and from −0.47 to −0.03 dB in the negative direction, while the typical insertion loss is from 2.23 to 2.61 dB, depending on the position of the hetero-core segment within the binary switch module. The connection of two binary switches in series is successfully demonstrated for monitoring the optical loss change on a single transmission line. The results of the present study show that the number of binary switches connected in series can be increased significantly on a single transmission line.     

光纤传感器及其在物业管理中应用

随着科技的发展,物业管理更趋于网络化、智能化,而传感器则是所有信息的来源,因此传感器在物业管理中发挥者越来越大的作用.由于光纤技术的不断发展,传输距离不断加大,价格下降,加上在技术性能上又有独到的优点,光纤传感器将在物业管理中越来越多地得到应用.本文介绍了光纤传感器及其在住宅物业安全管理中的应用的设计思想,并提出组成光纤传感器网络,利用神经网络技术对信号进行实时处理,达到实时监控的目的.     

基于键合图的光纤环绕制小张力控制结构的建模和仿真

光纤环是光纤陀螺中的核心部件。光纤环绕制的技术水平直接影响着光纤陀螺的精度,绕制过程中缠绕张力控制更是整个光纤环绕制中尤为关键的部分。介绍了键合图方法基本原理,并将其应用于光纤环绕制的张力控制分析中,通过分析全过程的键合图模型,导出了系统的状态方程,并依据一定的结构参数应用Matlab对其进行了仿真,同时对系统做了输出测试,验证了该模型的有效性,为实际工程应用和引入先进控制算法提供必要的理论基础。     

FADS压力传感器冗余配置研究

嵌入式大气数据传感器系统通过在飞行器各部位的压力传感器阵进行工作,压力传感器的数量,布局形式将对系统的工作性能产生影响.为衡量冗余配置的性能,提出两项性能指标:可靠件,噪声抑制性能,并分别给出性能指标的具体计算方法.根据现有典型的压力传感器布局类型,分别计算出不同压力传感器数量、不同布局形式的性能指标.通过对性能指标的分析得出结论:可靠性,噪声抑制性能随压力传感器数量增加而增加;放射型布局的噪声抑制性能最优.     

光纤传感器在灵巧结构与蒙皮中的应用

介绍了光纤传感器在飞行器结构上的应用，包括表面贴装与内埋光纤损伤探测系统，内埋的监测复合材料内部声波辐射的光纤应变传感器及测量复合材料的内应变张量的应变计，并介绍了光纤神经网络的初步研究。     

Contact CMOS imaging of gaseous oxygen sensor array

We describe a compact luminescent gaseous oxygen (O₂) sensor microsystem based on the direct integration of sensor elements with a polymeric optical filter and placed on a low power complementary metal-oxide semiconductor (CMOS) imager integrated circuit (IC). The sensor operates on the measurement of excited-state emission intensity of O₂-sensitive luminophore molecules tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) ([Ru(dpp)₃]²⁺) encapsulated within sol-gel derived xerogel thin films. The polymeric optical filter is made with polydimethylsiloxane (PDMS) that is mixed with a dye (Sudan-II). The PDMS membrane surface is molded to incorporate arrays of trapezoidal microstructures that serve to focus the optical sensor signals on to the imager pixels. The molded PDMS membrane is then attached with the PDMS color filter. The xerogel sensor arrays are contact printed on top of the PDMS trapezoidal lens-like microstructures. The CMOS imager uses a 32 × 32 (1024 elements) array of active pixel sensors and each pixel includes a high-gain phototransistor to convert the detected optical signals into electrical currents. Correlated double sampling circuit, pixel address, digital control and signal integration circuits are also implemented on-chip. The CMOS imager data is read out as a serial coded signal. The CMOS imager consumes a static power of 320 μW and an average dynamic power of 625 μW when operating at 100 Hz sampling frequency and 1.8 V DC. This CMOS sensor system provides a useful platform for the development of miniaturized optical chemical gas sensors.