共查询到19条相似文献,搜索用时 78 毫秒
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本文报导一种以SEC快门摄象管为图像传感器,CA5300图像卡为图像数据帧存贮体,微型计算机为控制中心的新型荧光光电成像系统。运用系统中独特的快门装置,做出了时间分辨成像,消除了背景荧光对成像的影响,并由微机对采集到的荧光图像进行必要的图像增强和噪声消除等处理后输出再显示,效果良好。文章最后给出系统在潜指纹荧光探测和细胞结构荧光探测两方面的应用研究及其结果。 相似文献
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在实验室建立了激光诱导荧光系统的氢氧自由基内标定方法,通过理论和证和实验检验,标定技术可以在较宽的浓度范围内对LIF系统进行标定,是一种原理简单的LIF标定技术。 相似文献
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介绍了毛细管电泳芯片的构造和原理,提出激光诱导荧光检测系统的设计方案及其主要器件的选择。分析了光电倍增管电压和共焦针孔对检测系统影响,并给出结果。实验表明,该系统主要技术指标达到了设计要求。 相似文献
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利用电磁波技术,设计了基于电磁波原理的同轴线相位传感器,提出了含气率测量的相移原理,给出了含气率与相位差的函数关系,并在内径50.0 mm的不锈钢测量管段进行了48个实验点的垂直管气液两相流截面含气率测量实验。实验结果表明:通过对3种现有模型的测量结果进行分析比较,Lockhart-Martinelli模型的测量结果与预测结果的平均绝对误差为18.32%,相较于其他2种模型更适用于弹状流的流型,该测量方法和测量模型具有一定的有效性和准确性。 相似文献
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针对生命科学研究中测试样品量极少的关键问题,以毛细管作为样品检测池,采用入射光与荧光原位进出的系统设计方案;以半导体泵浦固体激光器作为激发光源、高分辨紧凑型光谱仪作为探测器,构建了用于纳升级微量样品检测的原位激光诱导荧光系统。利用水溶液中罗丹明B浓度的测量来验证系统性能。结果表明,罗丹明B浓度在93pg/mL~15ng/mL范围内与荧光强度有良好的线性关系,相关系数为0.9982,检出限为28pg/mL,证实该系统具有低噪声、低试剂消耗、低检出限、高灵敏度和精确度等优点,可满足生物测试的实际使用要求。 相似文献
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氢氧自由基(OH)是对流层大气中最重要的氧化剂,对其浓度的测量具有重要意义。本文利用气体扩张激光诱导荧光技术(FAGE)建立了 OH 测定系统,并对可能存在的干扰进行了讨论。 相似文献
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A capacitance void fraction sensor (CVS) is applied to measure the volumetric averaged void fraction in a packed bed of spheres. The void fraction in the packed bed is one of the most important parameters to evaluate cooling characteristics in a porous debris bed during a severe accident of nuclear reactors, and the quantitative void fraction measuring technique for such porous flow channels should be developed. The CVS is a very simple method, and the void fraction is estimated from the electrical capacitance measured between the electrodes installed on the pipe. Generally, the linear relationship or Maxwell equation could be applied to estimate the void fraction from the capacitance measured by the CVS. However, the electrical field in the packed bed becomes complex due to the existence of spheres. Therefore, they may not be applied to the void fraction estimation in the packed bed. In this study, the CVS with a ring-type electrode configuration is used for the sphere-packed beds, and the applicability of the CVS is investigated. At first, the particle size and the pipe diameter are varied in the packed test section, and X-ray transmission imaging is used to clarify the relation between the void fraction and the capacitance in the packed bed. Then, it is found that the void fraction can be obtained by the coefficient in Maxwell's equation, depending on the packed bed properties. Finally, the measurement accuracy of the CVS for the sphere-packed bed is estimated by comparing it with a volumetric method, and the availability of the proposed method is shown. 相似文献
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为解决刑事案件中附着于渗透性纸张上的无色微量物证探测难的问题,分析常用纸张的紫外荧光特性,为滤除纸张上的强背景荧光提供依据,研制基于紫外光诱导荧光的渗透性纸张上微量物证检测装置。检测装置中,为有效激发各种微量物质荧光,采用光子能量高的深紫外激光作为激发光源;为获得更准确的痕迹信息,装置接收多光谱荧光并进行结果比对;同时,提出以背景灰度标准差来衡量纸张荧光的均匀性,以图像痕迹对比度评价痕迹的检测效果。使用本装置对常用纸张上的指印、明矾等5种无色痕迹开展实验验证,结果表明,所提方法能清晰显现纸张上的潜指印,且获得的指印条纹对比度与纸张背景灰度标准差成反比;同时,学生作业纸上的10%明矾溶液痕迹信息、复印纸上的2.5%谷氨酸钠溶液痕迹信息、便利贴上的2.5%磺酸钠溶液痕迹信息、便利贴上的0.004%硫酸铜溶液痕迹信息均能清晰显现。所提方法具有检测灵敏度高、非接触性、非破坏性、多光谱等优点,能快速获得高荧光纸张上多种微弱痕迹的清晰图像,为刑事侦查提供有力的帮助。 相似文献
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The sectional void fraction measurement for multiphase flow is usually influenced by flow patterns. Inspired by electrical capacitance tomography (ECT) devices applied to flow imaging (whose measured capacitance data contain both the flow pattern and sectional void fraction information), a capacitive array sensor is developed to realize two functions, flow pattern recognition and void fraction measurement, simultaneously; so that the void fraction measurement can be conducted for a certain flow pattern and the measurement accuracy can be expected to be improved. The main idea of the proposed method can be described as: firstly, the proper feature vectors are extracted from the electrical signal to identify the flow pattern (the BPNN model with GDX learning algorithm is used for flow pattern identification); and then the average of electrical signal is applied to estimates the void fraction by the corresponding calibration curve. An experimental platform of air/water two-phase flow is built (on which 3 flow patterns can be generated stably) to test the performance of the proposed method. The results support the correctness and effectiveness of the proposed method. 相似文献
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Void fraction is an essential parameter of gas-liquid two-phase flow and experiments were executed to investigate the void fraction fluctuation characteristics of gas-liquid two phase flow through a sudden expansion tube. Two 16 × 16 wires mesh sensors were applied to measure the phase distribution of upstream pipe(pipe-32) and downstream pipe(pipe-50). The superficial gas velocity is in the range of 3.46 m/s - 22.46 m/s and the superficial liquid velocity ranges from 0.034 m/s to 0.414 m/s. Flow pattern evolution of upstream and downstream pipes was reconstructed and compared. The experiment results show that, in contrast to pipe-32, the void fraction of pipe-50 shows different trends with the increase of liquid and gas velocity. Liquid-carrying capacity is essential in the relationship between the void fraction of pipe-32 and pipe-50. The critical superficial liquid and gas velocities are proposed to characterize the liquid-carrying capacity. The maximum critical superficial gas and liquid velocity is 15.56 m/s and 0.207 m/s, respectively. Besides, a model is proposed to describe the relationship of void fraction between pipe-32 and pipe-50. It is found that the prediction error is less than ±10% in the case of annular flow. 相似文献
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基于压缩感知关联成像的目标检测技术 总被引:1,自引:0,他引:1
高效率的目标检测是视觉应用的重要技术,但运动目标的提取易受环境的影响。关联成像能够解决特殊环境下难以获得清晰图像和一些常规成像技术不易解决的问题。在目标检测中,利用关联成像采集图像信息并运用背景差分法在压缩域中获得目标图像的测量值,直接通过压缩感知重构出目标图像。这种方法可以解决在特殊情况下无法检测到目标的问题,同时检测到的目标图像清晰,采样次数少,信噪比也较高。 相似文献
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为提高超声成像对比度和分辨力,研究了一种利用球壳聚焦阵列进行目标散射成像的方法。球壳聚焦阵列中的部分阵元发射聚焦声波,声波作用于目标后发生散射,回波被余下的阵元所接收,阵列中的发射阵元和接收阵元随机选择,以达到抑制旁瓣的作用。借助三维自动扫描机构,可获得聚焦波束沿被测物体表面的散射回波强度,从而实现对目标的成像。计算机仿真结果表明,球壳聚焦阵列可减小主瓣宽度,并有效降低聚焦波束旁瓣。水池实验结果表明,基于该阵列的散射成像方法具有亚毫米级的成像分辨力,能够获得较高对比度的图像。 相似文献