基于双波长像面数字全息显微的微通道检测

针对微流控芯片通道三维形貌的可视化测量需求,搭建了一套反射式离轴双波长像面数字全息显微测量系统。首先,利用分辨率靶和标准样片对系统的横向、纵向分辨率和放大倍数进行标定实验,结果表明双波长全息显微系统在横向宽度及纵向深度测量中具有较好的准确性和可行性。然后,利用该系统分别对由PDMS材料制成的直通道、圆形小室结构微流控芯片以及硅基底微流控芯片通道进行三维形貌检测,并得到定量结果：直通道结构深度为48.6μm,宽度为75.8μm;圆形小室微通道深度为48.5μm,宽度为76.6μm;硅基底微流控芯片测量得到通道深度为61.6μm。上述结果与白光干涉仪的测量结果具有良好的一致性,说明双波长全息显微系统具有较高的可靠性和准确性,可为微流控芯片微通道检测提供新的成像检测方法。     

面向冰盖剖面的高空间分辨率分布式光纤测温系统设计

针对现有冬季冰盖垂直剖面温度检测技术的不足,设计了一种具有高空间分辨率的分布式光纤测温系统,介绍了系统的测量原理和总体结构,提出使用反卷积校正算法,避免了因受系统有限带宽影响而导致的测温不准,从而提升空间分辨率。同时进行了相关测温实验。该算法可以在保证温度测量精度的前提下,将系统的空间分辨率从1.3 m提升至0.5 m。设计了一种具有垂直高分辨率的温度测量装置,可以精确检测冰盖内部垂直方向上的温度变化,实现对冰盖厚度的识别。     

一种提高分布式光纤测温系统空间分辨率的线性修正算法

由于分布式光纤喇曼测温系统带宽不足,导致系统的空间分辨率低;当光纤的感温区域长度接近空间分辨率的时候,系统温度响应幅值不够,导致测温不准.为解决此问题,本文提出了一种线性修正算法;在分析温度与喇曼比值关系及系统的频率响应特性的基础上,建立了该算法的数学模型,搭建了基于单模光纤的10 km分布式测温系统,并利用该算法进行了相关测温实验.实验结果与理论分析一致,该算法能有效修正3~6 m光纤的温度响应幅值,使系统测温准确度达1℃,测量时间为40 s.本算法在不增加效系统成本的同时,克服了系统带宽不足,优化了空间分辨率、温度分辨率及测量时间.     

一种提高分布式光纤测温系统空间分辨率的线性修正算法

由于分布式光纤喇曼测温系统带宽不足,导致系统的空间分辨率低;当光纤的感温区域长度接近空间分辨率的时候,系统温度响应幅值不够,导致测温不准.为解决此问题,本文提出了一种线性修正算法;在分析温度与喇曼比值关系及系统的频率响应特性的基础上,建立了该算法的数学模型,搭建了基于单模光纤的10km分布式测温系统,并利用该算法进行了相关测温实验.实验结果与理论分析一致,该算法能有效修正3～6m光纤的温度响应幅值,使系统测温准确度达1℃,测量时间为40s.本算法在不增加效系统成本的同时,克服了系统带宽不足,优化了空间分辨率、温度分辨率及测量时间.     

基于红蓝宝石光纤传感头的多通道光纤温度传感器

为了实现从室温到1000℃范围内的多点温度实时测量,基于红蓝宝石光纤传感探头,研制了一种连续快速温度测量的多通道光纤温度传感器.该系统结合了荧光测温和辐射测温原理,可同时测量8个传感探头的温度随时间的变化信号.提出基于面积平衡计算的数字迭代算法用来计算荧光寿命.与快速傅里叶变换算法的仿真对比结果表明,该算法计算速度快、抗噪声能力强、结果稳定性好、测量精度高.对系统进行长期的温度和稳定性实验,结果表明该系统具有较高的稳定性和测量精度,测温范围从室温到1000℃,精度达±1℃.     

聚甲基丙烯酸甲酯(PMMA)微流控芯片DNA分析系统的研制

生物分析是微流控芯片分析最具进一步发展及商品化前景的分支领域之一。报道了基于聚甲基丙烯酸甲酯(PMMA)微流控芯片DNA分析系统的研制。采用简易热压法自制的PMMA芯片,以小型光纤式激光诱导荧光为检测器,以四触点可切换1 800 V高压电源为电驱动系统,以2%羟乙基纤维素(HEC)为筛分介质,通过用于DNA分析的TO-PRO-3荧光染料和激光诱导荧光检测器670 nm截止滤光片的选择,构建了微流控芯片DNA分析系统。芯片凝胶电泳分离φX174-HaeⅢRF DNA片段, 以603 bp片段计算理论塔板数n为1.14×106·m-1, 271/281 bp的分离度R为1.2。建立的PMMA微流控芯片DNA分析系统具有制作和运行成本低,芯片可重复使用,分析重现性好等特点。该研究可用于制作微型化便携式DNA分析仪,应用于临床诊断、疾病筛查等领域。     

基于微流控技术的双颗粒体散射函数测量实验研究

本文通过流体力学及COMSOL等仿真软件分析,以PDMS为材料,设计制作了用于捕获两个球形颗粒样品的微流控芯片,并基于光电倍增管(PMT)和电动位移平台,搭建了角度扫描式大动态范围散射光测量装置。该系统可以快速捕获两个球形颗粒,在颗粒捕获后对微流控芯片内沟道与外轮廓进行折射率匹配,持续测量实际捕获颗粒的1°至170°的散射光。对23.75μm、31.10μm、40.01μm三种粒径的聚苯乙烯标准颗粒样品进行了实验研究,并多次重复测量同一粒径双颗粒的散射光分布。基于微流控芯片的双颗粒体散射函数测量方法可以稳定的捕获、释放双颗粒,实验操作简单且具有较好的重复性,在颗粒物体散射函数研究方面具有很大的潜力。     

时域两维荧光寿命显微测量研究

提出了一种新的时域两维荧光寿命显微测量技术,建立了一套荧光寿命成像显微系统,介绍了这种测量技术的数据处理方法。用标准样品对该系统进行了测试,实验表明,该系统的时间分辨率为2ps,在放大倍率为100倍的情况下,该系统的空间分辨率为8um。如果在现有的设备下采用更细的网格板和微位移系统,那么该系统的空间分辨率可小于1um.     

用于微流控液滴检测的共焦激光诱导荧光检测系统

以发射波长为473nm的二极管泵浦激光器为激发光源,搭建适于微流控液滴检测的共聚焦激光诱导荧光检测系统.系统玻璃芯片采用简易加工技术加工而成.并用2%十八烷基三氯硅烷将微通道处理为具有强疏水性质.荧光素钠溶液在T形通道交叉处被十四烷剪切形成液滴,液滴流经检测点时被激光诱导荧光系统检测.荧光素钠的检出限为1.1×10<'...     

炸药爆轰瞬态温度的光谱法测定

在双谱线原子发射光谱测温原理的基础上,设计了对炸药爆轰的瞬态温度进行实时测量的光纤光谱测试系统,利用光学纤维将炸药爆轰的光谱信号传入测光系统,用多通道数据采集器处理数据,系统的时间分辨率可高达0.1μs,所选择的两条谱线的波长分别为CuI 510.5和CuI 521.8nm,为炸药爆温的测量提供了一种简单有效的方法。利用该测温系统,通过对炸药爆轰光谱的测量,获得了实时瞬态爆轰温度-时间分布曲线。     

The future of 3-D range image measurement using binary-encoded pattern projection

3-D range image measurement using image processing is well established in a variety of applications as a reliable industrial measurement technique. Various triangulation-based techniques have been developed, using temporal or spatial binary encoding to uniquely identify each measured point. These are reviewed, and a new adaptive technique using a binary encoded sequence, combining spatial and temporal variation, is described.     

Studies on Temporal Resolution Characteristics of Flame Temperature for Flame Atomic Absorption Spectroscopy

In this paper we report a method and experiment system developed by us to useful for temporal and spatial temperature distribution of the flame for atomic obsorption spectroscopy in detail. The method and system principle is based on the modified sodium line reversal method. The studies on temporal (20–50 μsec range) and spatial (π 1mm) resolution of the flame temperature aim at establishing optimum analysis conditions and improving analysis characteristics of flame atomic absorption/emission spectroscopy.     

基于GF-4PMI数据的亮温差校正火点检测方法研究

高分四号PMI可为防灾减灾提供稳定数据,其搭载的中红外传感器可以很好地应用于快速火灾监测中。但由于缺少传统火灾监测的热红外波段,高分四号提供的光谱信息大多作为灾中监测的辅助数据,且现有的火点识别研究所构建的火点自适应阈值检测算法受单一波段的影响,错检率和漏检率均偏高。为进一步探究高分四号数据在林火监测中的应用方法,提高火点识别精度,本研究分析高分四号数据的特点,结合单通道红外光谱的火点监测方法,应用上下文思想提出一种基于双时相影像的亮温差校正火点检测的方法来进一步提高检测精度。该方法使用灾前和灾中两期影像,具体分为时间尺度上基于空间插值的亮温补偿获取,空间尺度上的上下文自适应阈值分割以及火点判识三个部分。首先将两期影像做差值处理,并将潜在火点周围动态邻域内其他无污染像元的亮温差作为采样点进行空间插值,随后将插值结果带入灾前影像中得到灾中未发生火灾时的背景亮温,最后利用判别条件进行火点判别和虚警剔除,得到最终火点检测结果。其中在灾中背景亮温的预测研究对比了反距离加权插值(inverse distance weigh)、简单克里金插值(simple kriging)和普通克里金插值(ordinary kriging)三种插值方法,从拟合结果来看普通克里金插值既体现了像素区域的波动性又有一定的平滑效果避免峰值过高,是较为理想的拟合结果。实验以目视解译的火点数据为参照验证了山西沁源县和内蒙古呼伦贝尔新巴尔虎左旗地区的两起火灾,对比最新提出的单时相火点检测算法,研究结果表明引进的亮温差校正数据可以更好地拟合背景亮温,减少错分误差至3%,并保持综合评价指标F_β分数在0.9以上。该方法有效结合了高分四号空间和时间的信息,未来可用于高分四号PMI数据自动化火点检测与快速提取。     

On the coherence measurement of a narrow bandwidth dye laser

In this paper, we report a new technique for spatial and temporal coherence measurement of narrow bandwidth sources. In particular, coherence measurement of a narrow bandwidth dye laser using Young’s double slit method and the Fabry–Perot interferometer has been carried out. In the spatial coherence measurement, a central fringe visibility of 0.85 was observed, and from this measurement, the dye gain medium source size was estimated. The variation in the visibility with slit separation (0.1–3.0 mm) for different source sizes (0.1–0.2 mm) was also analyzed. The temporal coherence length of the tunable dye laser was measured to be 10 and 60 cm for multimode and single-mode operations, respectively. The technique, in general, can also be used for spatial and temporal measurement of broadband spectrum source.     

激光等离子体温度测量方法设计

为了获得高时间和空间分辨率的激光等离子体温度测量结果,基于等离子体温度测量的二谱线法,设计了一种激光等离子体温度测量方法。介绍了该方法的测量原理及时间空间分辨率实现方法。利用这种方法获得了空间分辨率微米量级、时间分辨率纳秒量级的激光等离子体温度测量结果,测量得到的激光等离子体温度为10^4K量级。实验结果表明,该方法能够获得具有很高时间空间分辨率的温度测量结果,具有较好的可行性。     

Inverse analysis of non-uniform temperature distributions using multispectral pyrometry

Optical diagnostics can be used to obtain sub-pixel temperature information in remote sensing. A multispectral pyrometry method was developed using multiple spectral radiation intensities to deduce the temperature area distribution in the measurement region. The method transforms a spot multispectral pyrometer with a fixed field of view into a pyrometer with enhanced spatial resolution that can give sub-pixel temperature information from a “one pixel” measurement region. A temperature area fraction function was defined to represent the spatial temperature distribution in the measurement region. The method is illustrated by simulations of a multispectral pyrometer with a spectral range of 8.0–13.0 μm measuring a non-isothermal region with a temperature range of 500–800 K in the spot pyrometer field of view. The inverse algorithm for the sub-pixel temperature distribution (temperature area fractions) in the “one pixel” verifies this multispectral pyrometry method. The results show that an improved Levenberg–Marquardt algorithm is effective for this ill-posed inverse problem with relative errors in the temperature area fractions of (–3%, 3%) for most of the temperatures. The analysis provides a valuable reference for the use of spot multispectral pyrometers for sub-pixel temperature distributions in remote sensing measurements.     

Temperature measurement of air convection using a Schlieren system

In this work, we have developed a procedure for full-field measurement of temperature of a fluid flow by using the schlieren technique. The basic idea is to relate the intensity level of each pixel in a schlieren image to the corresponding knife-edge position measured at the exit focal plane of the system. The method is applied in the measurement of temperature fields of the air convection caused by a heated rectangular metal plate (7.3 cm×12 cm). Our tests are carried out at plate temperatures of 50 °C and 80 °C. To validate the proposed method, the schlieren temperature results are compared to those obtained by a thermocouple. Thermocouple data are obtained along two mutually perpendicular directions (one direction along the optical axis, z-direction, and other direction along the x-axis, which is perpendicular to the optical axis) at points located on a 9×9 grid with a variable spacing. The thermocouple measurements were integrated along the z-axis in order to be compared with the measurements obtained by the schlieren technique. The results from the two methods show good agreement between them.     

Real-time imaging of the spatial distribution of rf-heating in NMR samples during broadband decoupling

Continuous radio-frequency (rf) irradiation during decoupling and spin-lock periods in NMR pulse sequences may lead to undesired sample heating. Heat-sensitive samples can suffer damage from the sudden temperature rise which cannot be adequately compensated by the temperature control system. Moreover, as the heating is spatially inhomogeneous, higher temperature increases can arise locally than are indicated by the average increase detected by the temperature controller. In this work we present a technique that allows measurement of a real-time 2D-image of the temperature distribution inside an NMR sample during an experiment involving rf-heating. NMR imaging methods have previously been used to project the temperature distribution inside an NMR sample onto a single spatial axis or to acquire steady-state 2D- temperature distributions. The real-time 2D-temperature profiles obtained with our procedure provide much more detailed data. Our results show, that not only inhomogeneous heating but also inhomogeneous sample cooling contribute to the build-up of temperature gradients across the sample. The technique can be used to visualize rf-heating in order to protect sensitive samples and to experimentally test new coil geometries or to guide probehead design.     

Measurement of impurity and temperature variations in water by interferometry technique

Refractive index is an important optical parameter of liquids, which is temperature, concentration and wavelength-dependent. Therefore, precise measurement of refractive index variation can be used for precise determination of the above parameters. In this paper a laser-based interferometry technique was introduced for accurate measuring of the refractive index variation due to temperature, and concentration changes. Distilled water was used as a test liquid sample, however the technique can be applied for any similar liquids. The concentration variations of distilled water due to three different impurities i.e. ethanol, salt water and tap water were examined. The technique gives measurement for concentration and temperature variations typically at the order ∼10⁻⁴(g/l)⁻¹ and 10⁻⁵ K⁻¹ respectively. The results show the variations of refractive index with respect to temperature or concentration can be measured typically with an accuracy of ∼6%, and 10% respectively. The method is useful for fast and precise monitoring of temperature and concentration variations in transparent liquids.     

On the proposal of quantitative temperature measurement by using three-color technique combined with several infrared sensors having different detection wavelength bands

We developed the previous infrared sensing technique, the two-color technique, to establish further a more general technique to measure the temperature quantitatively under near-ambient conditions. The quantitative temperature measurement, three-color technique, was newly proposed by combining three kinds of infrared radiometers having different detection wavelength bands. The measurement can also be done by adding three infrared filters to one infrared radiometer. The radiometers have a selective detection wavelength band of several μm in width which is in the range of 2–13 μm. The method was confirmed using numerical simulation to allow a parametric study of how the result varies for different values of emissivity corresponding to the respective infrared radiometers. An experimental investigation was also performed to evaluate the measurement error and the adaptability of the technique. As this technique has a feature that can perform quantitative temperature measurement for objective surfaces at each picture element without presuming any emissivity, reflectivity and ambient conditions, there is a possibility that the technique will be useful for various medical or engineering disciplines.