基于Mach-Zehnder干涉的光子晶体光纤传感技术研究进展

近年来,随着光纤传感器技术研究领域的不断发展,各式各样的光纤传感结构脱颖而出.其中,采用光子晶体光纤与Mach-Zehnder干涉相结合方式的传感研究引起了学术界广泛关注.分析了国内外基于Mach-Zehnder干涉的光子晶体光纤传感技术的研究进展,介绍了这种技术在折射率测量、温度和多参数测量、应变与曲率测量等应用的传感结构,并对其发展前景进行了展望.     

黑体腔光纤高温传感器的原理与应用

光纤传感技术是近年来测量领域的热点之一。由于测量环境的恶劣和限制，使得在某些工业环境中，光纤传感技术的抗电磁干扰、耐腐蚀、防燃防爆等优势得以发挥，得到广泛的应用。本文研究了光纤温度传感的原理，并介绍了一种新型的光纤高温传感器。     

空芯光子带隙光纤在甲烷检测中的应用

本文所提出的新型的全光纤甲烷检测系统是依托空芯光子带隙光纤作为检测气体传感的探头,利用谐波检测技术处理信号的一种甲烷检测方式。旨在正确分析甲烷气体在空芯光子带隙光纤中的扩散特性,从而对传感气室实现优化设计。另外,研究通过实际的试验成果证实利用空芯光子带隙光纤进行甲烷检测具有一定的可行性。     

光纤布喇格光栅传感器应用系统

综述了光纤布喇格光栅及在传感技术领域的应用，包括光纤布喇格光栅传感器原理及特点，光纤传感单参量测量，双参量测量及分布式多点测量系统。提出并实现了一种用PZT－应变片组合型高线性度光纤光栅探测反射波长移位的方法。     

基于嵌入式的布里渊分布式光纤传感远程网络控制系统

光纤传感器正向多点检测、远程控制、网络化方向发展,本文提出一种基于嵌入式的光纤传感远程网络控制系统设计方案,对传感原理、FPGA控制、数据的远程传输和采集参数控制进行了分析,并针对分布式光纤传感节点多、数据流量大的特点,应用多线程和线程槽技术到系统构建,完成了光纤传感网络的实际检测.     

一种基于光纤光栅压力传感阵列的飞机燃油液位测量方法研究

本文提出了一种基于光纤光栅压力传感器阵列的飞机燃油液位传感系统,研究了基于聚氨酯材料的压力敏感薄膜和光纤光栅压力传感器的制造工艺,通过光纤光栅(FBG)压力传感器阵列搭建了燃油液位传感系统,开展了液位传感实验。实验结果表明,该系统在75cm液位量程范围内可实现16.09pm/cm的测量灵敏度,最大相对误差<４％。论文提出的基于线性拟合曲线截距测量的液位高度计算方法,可以克服实际应用中测量液体密度和重力加速度变化对液位测量精度的影响,保证了系统的检测精度。该光纤光栅液位传感器为飞机燃油液位检测提供了一种新的技术思路。     

光纤光栅传感器技术及其在电力系统中的应用

在分析Bragg光纤光栅和长周期光纤光栅传感测试技术工作原理的基础上,系统总结了光纤光栅传感器在电力系统中的应用.对光纤光栅传感技术在电力电缆监测、汽轮机内部湿度场监测、高压开关柜隔离触头温度监测、线圈绕组温度监测、风力发电机叶片的监测及发电机绕组端部的振动测量几个方面的应用做了具体的阐述和实用价值的分析,本文还提出了基于磁致伸缩材料GMM的光纤光栅电流传感器的测量模型,理论计算灵敏度达到了0.0888nm/A.     

黑体腔光纤高温传感器的原理与应用

光纤传感技术是近年来测量领域的热点之一。由于测量环境的恶劣和限制,使得在某些工业环境中,光纤传感技术的抗电磁干扰、耐腐蚀、防燃防爆等优势得以发挥,得到广泛的应用。本文研究了光纤温度传感的原理,并介绍了一种新型的光纤高温传感器。     

分布式光纤传感器应变传递性能分析及试验研究

分布式光纤传感技术是一种新型光电监测技术,可实现应变、温度的长距离分布式检测,适用于土木工程结构的健康监测.应变量测的准确性是进行结构健康诊断和评估的关键,其中影响分布式光纤传感技术应变测量精度的因素除了设备自身性能,还与感应结构应变信号的分布式光纤传感器的应变传递性能有关.从理论上分析了传感光纤特性、粘结剂物理性质、...     

基于长周期光栅滤波的全光纤光纤光栅传感器研究

设计了一种全光纤传感测试系统,采用长周期光纤光栅作为边带滤波器,对光纤布拉格光栅的传感信息进行解调,结合高信噪比的光电测量系统,传感测量的波长检测灵敏度为１．９４ｄＢ／ｎｍ,波长测量分辨率可达０．０５ｎｍ。     

啁啾光纤光栅的光谱特性研究

在啁啾光栅中2个模式之间会发生耦合,要了解啁啾光栅的物理和传感特性,提高反射谱的精度,就必须对啁啾光栅的耦合模理论做深入研究。通过啁啾光栅的耦合方程,并采取合适的坐标变换,利用Matlab进行了数值模拟仿真研究,分别讨论了啁啾光栅耦合模型在不同的折射率调制、不同光栅长度、不同光栅周期和啁啾系数对啁啾光纤光栅反射谱的影响,进一步的研究了啁啾光栅的光谱特性。     

Quantitative monitoring of inland water using remote sensing of the upper reaches of the Huangpu River,China

In this paper, a quantitative framework using common and readily available remote sensing data, including ground hyperspectral data, multispectral remote sensing images and a regular in situ water quality monitoring programme, is proposed to monitor inland water quality. The entire framework has three steps: (1) collecting and processing basic data, including remote sensing data and water quality data; (2) examining the relationships between water quality parameters and water reflectance from both remote sensing images and in situ measurement data. According to their relationships with ground hyperspectral reflectance, the water quality parameters are classified into three categories, and the corresponding monitoring models using remote sensing data are presented for these three categories; and (3) analysing the spatial distribution by using water quality concentration maps generated with the monitoring models. The upper reaches of the Huangpu River were chosen as our study area to test this framework. The results show that the concentration maps inverted by the proposed models are in accordance with the actual situation. Therefore, we can conclude that the proposed framework for quantifying water quality based on multisource remote sensing data and regular in situ measurement data is an effective and economic tool for the rapid detection of changes in inland water quality and subsequent management.     

Inversion of vegetation canopy reflectance models for estimating agronomic variables. I. Problem definition and initial results using the suits model

An important but relatively uninvestigated problem in remote sensing is the inversion of vegetative canopy reflectance models to obtain agrophysical parameters, given measured reflectances. The problem is here formally defined and its solution outlined. Numerical nonlinear optimization techniques are used to implement this inversion to obtain the leaf area index using Suits' canopy reflectance model. The results for a variety of cases indicate that this can be done successfully using infrared reflectances at different views or azimuth angles or a combination thereof. The other parameters of the model must be known, although reasonable measurement errors can be tolerated without seriously degrading the accuracy of the inversion. The application of the technique to ground based remote-sensing experiments is potentially useful, but is limited to the degree to which the canopy reflectance model can accurately predict observed reflectances.     

基于地表参数真实性的GF-1和SPOT-7多光谱影像质量评价

目的 遥感影像中地表信息表达真实程度决定了影像信息提取和定量化应用水平,传统的从像素灰度和视觉特性角度的影像质量评价方法难以评价影像对地表信息表达能力,本文从地表反射率和NDVI（normalized difference vegetation index）两种地表参数真实性角度评价GF-1和SPOT-7多光谱影像质量。方法 提出了一种基于地表参数真实性的多光谱影像质量评价方法,完成GF-1和SPOT-7卫星对实验区同步成像,地面同步测量大气光学特性和典型地物样区光谱,获取同步观测数据并对多光谱影像进行辐射误差处理,计算地物样区在影像上的反射率和NDVI,通过与地面实测光谱数据比较分析了地表参数真实性,评价GF-1和SPOT-7多光谱影像质量。结果 人工靶标中GF-1影像在4个波段反射率误差均在5%内,精度优于SPOT-7;植被地物中SPOT-7影像在蓝绿红波段反射率误差在4%内,近红外波段误差在15%内,NDVI误差在16%内,反射率和NDVI精度均优于GF-1;硬地地物中GF-1影像在4个波段反射率误差在6%内,精度优于SPOT-7;评价结果表明SPOT-7多光谱影像对植被类地物光谱表达真实度更高,GF-1对硬地类地物光谱表达真实度更高。结论 提出的基于地表参数真实性的遥感影像质量评价方法,能够有效地从地物光谱信息表达精度的角度评价影像质量。     

平行螺旋传输线用于岩土形变分布式测量的机理研究

提出了一种平行螺旋传输线作为传感电缆用于岩土形变位移的分布式测量,基于建立的拉伸分布参数模型,推导了传感电缆特性阻抗与岩土拉伸量的关系并给出了拟合函数。根据编写的上位机程序计算出其特性阻抗的变化从而实现了岩土拉伸位置的定位测量,再利用拟合函数,确定拉伸量的大小,最终求得岩土形变的拉伸总量。为了验证理论分析的正确性,设计了基于时域反射技术的形变测量系统,对平行螺旋传输线进行了局部多点拉伸的定位及形变测量实验,实验测量结果和理论计算结果吻合度很好,为平行螺旋传输线在岩土形变分布式测量的应用提供了有力的理论分析和实验验证。     

基于蚀刻结构的强度调制型光纤传感器􀀂

本文介绍了有着蚀刻结构的光纤传感器在应变测量以及薄结构振动测量中的应用和检测机理 .并且在非对称蚀刻结构的光纤曲率传感器的基础上提出了分布式光纤模态曲率传感器研究     

基于同步实测光谱数据的ASTER影像邻近效应校正研究

2008年6月在甘肃省张掖市开展的天-空-地同步大型遥感实验“黑河综合遥感联合实验”中,用自己设计的装置在兰州大学草地观测站开展了卫星同步邻近效应测量实验,用逆最小二乘算法求算了邻近效应校正系数,并将系数应用于影像真实反射率转换方程,对同步获取的ASTER影像进行了邻近效应校正,校正结果影像质量有所改善。将校正的结果影像与SHDOM方程的邻近效应校正结果影像对比,结果表明,经过邻近效应校正系数校正后影像的反射率、归一化植被指数产生较大差异,像元之间的相关性也明显降低。     

Spectral discrimination of healthy and Ganoderma-infected oil palms from hyperspectral data

Although hyperspectral remote sensing has been used to study many agricultural phenomena such as crop stress and diseases, the potential use of this technique for detecting Ganoderma disease infestations and damage to oil palms under field conditions has not been explored to date. This research was conducted to investigate the feasibility of using a portable hyperspectral remote-sensing instrument to identify spectral differences between oil-palm leaves with and without Ganoderma infections. Reflectance spectra of samples representative of three classes of disease severity were collected. The most significant bands for spectral discrimination were selected from reflectance spectra and first derivatives of reflectance spectra. The significant wavelengths were identified using one-way analysis of variance. Then, a Jeffries–Matusita (JM) distance measurement was used to determine spectral separability between the classes. A maximum likelihood classifier method was used to classify the three classes based on the most significant wavelength spectral responses, and an error matrix was finally used to assess the accuracy of the classification.     

A novel portable LCD using a new AFFS technology for outdoor readability

Abstract— The advanced fringe‐field switching (AFFS) mode is suitable for portable display devices. It has high transmittance, wide viewing angle, low power consumption, high contrast ratio, and a ripple‐free property resistant to pressure. Recently, a 10.4‐in. XGA prototype which demonstrates excellent transmittance and very good outdoor readability has been developed. To obtain these properties, a new pixel structure has been designed which has a large aperture and a metal embossing pattern for inner reflectance without the use of a black matrix on the embossing metal pattern. Precise control of the liquid‐crystal electrodynamics and surface reflectance using an AR polarizer was achieved. This new panel shows distinguished characteristics for outdoor readability with the backlight on under a bright outside light source.     

基于数据融合的倾斜光纤光栅应变测量

倾斜光纤光栅的透射谱中除了纤芯模之外还有一系列包层模。倾斜光纤光栅各个模式的应变传感特性是不同的,因此,可将每一个模式作为一只应变传感器测量应变。提出了利用倾斜光纤光栅的多个模式作为应变测量的多只传感器,在此数据测量基础上,采用数据融合方法提高数据测量的精度,从而得到应变的准确信息。这种方法计算简便,编程容易,在实际测量系统中具有很好的应用价值。