强度解调型光纤光栅温度传感实验

光纤光栅在工程上应用广泛,但由于存在解调系统复杂、成本高,尤其是需要使用光纤光谱仪等波长解调仪器,使得光纤光栅很难走入本科教学的实验课堂.本文提出了一种基于窄线宽DFB激光器的强度解调方案,极大地简化了光纤光栅传感器的解调系统,完全满足较高分辨率和实时检测的系统要求.合理安排的温度传感实验可以非常直观地展示光纤光栅的线性传感性能,使得工程化的光纤光栅传感技术轻松走进本科教学课堂,具有极高的推广和应用潜力.     

工业SO2及碳黑颗粒紫外成像遥感监测技术

为了准确有效监测工业烟囱排放,基于SO2及碳黑颗粒物的光学特性,设计并研制出一套双通道紫外成像遥感监测系统.该成像系统的两个光谱通道的中心波长分别定于310 nm和330 nm,利用两个通道的光学厚度之差反演SO2浓度图像,颗粒物浓度图像由330 nm通道获取,根据浓度图像结合光流法获取烟羽运动速度,进而计算得出SO2和碳黑颗粒物的排放速率.结果表明,该工业烟囱的SO2及碳黑颗粒物排放速率分别为72.48±3.16 kg/h和6.33±1.18 kg/h.实验采用紫外相机同时对工业烟囱排放的SO2及碳黑颗粒物进行监测,实验表明双通道紫外成像遥感监测兼具高时间分辨率与高空间分辨率,测量结果准确直观,在工业废气污染、船舶尾气污染以及火山喷发污染排放遥感监测中具有非常明显的技术优势及巨大的应用前景.     

Enhancing optomechanical force sensing via precooling and quantum noise cancellation

We theoretically investigate optomechanical force sensing via precooling and quantum noise cancellation in two coupled cavity optomechanical systems.We show that force sensing based on the reduction of noise can be used to dramatically enhance the force sensing and that the precooling process can eifectively improve the quantum noise cancellation.Specifically,we examine the effect of optomechanical cooling and noise reduction on the spectral density of the noise of the force measurement;these processes can significantly enhance the performance of optomechanical force sensing,and setting up the system in the resolved sideband regime can lead to an optimization of the cooling processes in a hybrid system.Such a scheme serves as a promising platform for quantum back-action-evading measurements of the motion and a framework for an optomechanical force sensor.     

THE MODIFIED TRIPLES ALGORITHM FOR FLUSH AIR DATA SENSING SYSTEM APPLIED TO THE VEHICLE WITH BLUNT FORE-BODIES1)

针对传统的用于钝头体飞行器的嵌入式大气数据传感系统的经典三点式算法对测压孔配置约束性严格的特点,对经典三点式算法进行了改进及验证。首先,对于经典三点式算法及改进算法进行了论述;其次,针对不同测压孔配置对算法精度的影响进行了系统的评估;最后,对于传统的经典三点式算法与改进三点式算法的优劣进行了比较。结论为：(1)改进的三点式算法对于测压孔的配置敏感性变差,即对测压孔约束很宽松,可用测压孔数增加,从而使得算法的适用性更强;(2)改进的三点式算法的精度与三点式算法相当,但是需要对测压孔进行系统选取及对比验证。     

一种新型双参量光纤布喇格光栅传感器的研制

介绍了一种新型的具有双参量测量功能的光纤布喇格光栅传感器.该传感器采用了特殊的结构,安装了两个不同中心波长的光纤布喇格光栅,可以实现两曲面之间狭小间隙的微小位移和温度的同时测量.实验表明,该传感器结构紧凑、体积小,具有良好的重复性和稳定性,位移测量误差不超过±10 μm,温度测量误差不超过±2℃.     

熊猫型保偏光纤光栅温度和压力传感特性的实验研究

对熊猫型保偏光纤光栅的传感特性进行了深入的实验研究,采用温箱和压力罐分别进行了温度和压力传感特性的实验研究.实验结果表明:在0～2.5 MPa的压强范围内,熊猫型保偏光纤光栅两个偏振方向上的压力敏感系数分别为0.004 88 nm/MPa和0.003 52 nm/MPa;在15～50 ℃的温度范围内,两个偏振方向上的温度敏感系数为0.01018 nm/℃和0.008 8 nm/℃.该光纤光栅两偏振态对温度和压力的不同敏感特性可用于解决光纤光栅的交叉敏感问题.     

内陆水体叶绿素a含量定量检测的研究

以武汉东湖为实验基地,通过对其水体的多次检测,获得了从2006年6月到9月4个月的东湖水体透射光谱,并与蒸馏水透射光谱进行比较,对东湖水富营养化程度进行了定性分析.采用一种新的测量方法得到叶绿素a浓度与677 nm和703 nm处相对强度的差值和比值有很好的线性相关性,建立了东湖水体叶绿素a含量的准确定量检测模型,为实现对东湖水实时、快速、准确监测提供了基础,为高精度遥感水质分析提供了参考.     

高灵敏度高选择性气敏材料--金属酞菁配合物

酞菁配合物是一类重要的光电功能材料.由于它的特殊结构使其成为高灵敏度高选择性气敏材料,具有极好的应用前景.本文在介绍酞菁配合物的结构特点、合成方法、气敏特性及其最新研究进展的基础上,讨论了酞菁配合物的气敏机理及膜结构、中心金属和取代基对气敏性的影响,并对酞菁配合物作为气敏材料的发展趋势进行了展望。     

Convergence of hormones and autoinducers at the host/pathogen interface

Most living organisms possess sophisticated cell-signaling networks in which lipid-based signals modulate biological effects such as cell differentiation, reproduction and immune responses. Acyl homoserine lactone (AHL) autoinducers are fatty acid-based signaling molecules synthesized by several Gram-negative bacteria that are used to coordinate gene expression in a process termed “quorum sensing” (QS). Recent evidence shows that autoinducers not only control gene expression in bacterial cells, but also alter gene expression in mammalian cells. These alterations include modulation of proinflammatory cytokines and induction of apoptosis. Some of these responses may have deleterious effects on the host’s immune response, thereby leading to increased bacterial pathogenesis. Prokaryotes and eukaryotes have cohabited for approximately two billion years, during which time they have been exposed to each others’ soluble signaling molecules. We postulate that organisms from the different kingdoms of nature have acquired mechanisms to sense and respond to each others signaling molecules, and we have named this process interkingdom signaling. We further propose that autoinducers, which exhibit structural and functional similarities to mammalian lipid-based hormones, are excellent candidates for mediating this interkingdom communication. Here we will compare and contrast bacterial QS systems with eukaryotic endocrine systems, and discuss the mechanisms by which autoinducers may exploit mammalian signal transduction pathways.     

Microfluidic differential resistive pulse sensors

This study demonstrates an on-chip resistive pulse-sensing scheme with a design of symmetric mirror channels, which significantly reduces the noise and achieves better signal-to-noise ratio. Polystyrene particles of different sizes have been detected with the developed sensing scheme and a record low volume ratio of the particle to the sensing channel, or 0.0004%, has been detected with particles of 520 nm in diameter in a sensing aperture of 50x16x20 microm3. This volume ratio is about ten times lower than the lowest volume ratio reported in the literature including that specified for commercial Coulter counters.