为了提高鸡蛋中的血斑和肉斑的检测准确率,给消费者提供高品质的鸡蛋,该文利用微型光纤光谱仪采集鸡蛋的透射光谱,在单分类器的基础上,通过多分类器的融合对异物蛋进行检测?首先根据差异性度量选取朴素贝叶斯,adaboost 和svm 分类器作为单分类器,然后通过特征级融合选取了5 个基分类器?最后,5 个基分类器以加权投票机制进行决策级融合?多分类器融合对正常蛋和异物蛋的检测准确率分别为92.86%和 91.07%?试验结果表明,利用多分类器融合所建立的模型优于单一分类器的模型,提高了对异物蛋的检测准确率?
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随着工业的发展，产品的测量精度有待进一步提高，绝对距离的测量装置在近几年更是需要改善。为此本课题研究了一种基于白光干涉测量装置来测量绝对距离。本论文从理论研究和实用角度出发，深入研究了白光谱域干涉的原理和特性，介绍了通过分析白光干涉光谱进行绝对距离测试的方法。文章主要研究白光干涉测量系统：利用白光michelson干涉仪组成的干涉系统，usb2000光纤光谱仪来接受与绝对距离相关的干涉光谱信号。文章详细论述了系统的测量原理、测量装置、数据处理及实验验证。在本论文研究的系统的最后输出信号只与干涉仪的臂长差有关，而与其在测量光路的相位无关，因此，该测量系统有效地提高了系统的抗振能力；同时，利用频谱域白光干涉原理提高了测量范围和抗干扰能力。
以南疆红枣颜色快速分级为研究对象,采用美国海洋光学usb650 红潮光谱仪来测量红枣的颜色特征值,采用红枣颜色按l[微软拥护1]值分级时,一级红枣的l 值为30. 2 ~ 35. 4,二级红枣的l 值为35. 5 ~ 39. 9,三级红枣的l 值为40. 0 ~44. 6,按l 值分级与人工分级的一致度为93. 65%; 以红枣的l?a?b 值作为特征值,应用bp 人工神经网络进行分级,bp 人工神经网络分级与人工分级的一致度达到了94. 76%?结果表明,以l?a?b 三个颜色值分级效果要好于仅以l 值分级,bp 人工神经网络分级效果优于人工分级,较好地满足红枣颜色分级的需求,对南疆红枣产品的加工?销售具有一定的理论指导和实际应用意义?
根据色度学原理,利用美国ocean optics公司的usb2000 光纤光谱仪对黄色翡翠进行测量与分析,量化黄色翡翠颜色的参数指标,包括其cie 1931色度坐标?主波长?彩度?明度和cie1931色品图等?依据主波长及色调角,可区分黄色翡翠颜色的主色调?实验结果表明,利用光纤光谱仪?适当的照明方式及光谱采集方法,应用色度学原理,可以客观?定量地描述黄色翡翠的颜色,可作为评价黄色翡翠颜色的适用技术?
采用usb2000 微型光纤光谱仪测试了湖北秦古绿松石样品的可见吸收光谱, 结果表明, 该样品在可见光范围内存在a1(425 ～ 428 nm)和a2(683 ～ 688 nm)两处特征的吸收宽谱带,其可见吸收光谱主波长和纯度的变化与颜色特征具有一定的对应关系。根据变温实验中样品的可见变温吸收光谱和差热测试结果推测,秦古绿松石的颜色特征与其所含fe 离子价态、水的存在形式及其质量分数有一定的关系。
a new method using surface enhanced raman spectroscopy (sers) with au nanoparticles was established for the rapid detection of benzylpenicillin potassium (pg) residues in duck meat. au nanoparticles were used as sers enhancement substrate, and the maximum absorption peak of au nanoparticles using the uv-vis spectrophotometer was 548 nm. in the research, the sers spectra of pg solutions and pg duck meat extract as well as their vibrational assignment were analyzed. the effects of au nanoparticles addition, sample addition, nacl solution addition, and adsorption time on the sers intensities of pg duck meat extract were discussed. it is revealed that a good linearity can be obtained between the sers intensities at 993 cm?1 and the pg residues concentrations (0.5?15.0mg?l?1) detected in duck meat extract.the linear equation was ?? = 831.68?? 1997.1, and the determination coefficient was 0.9553. the determination coefficient of pg in duck meat extract between the actual values and the predictive values was 0.9757, and the root mean square error (rmsep) was 0.6496mg/l. the recovery rate of pg in duck meat extract was 90?121%.the results showed that the method using sers with au nanoparticles could pave a new way for the rapid detection of pg residues in duck meat.
one of the primary advantages of nanoscale sensors is that they often can provide conceptually new ways of performing sensing that are nor feasible with their large-scale analogs. for example, the small size of nanoscale sensor elements, such as plasmonic metal nanoparticles, allows them to be combined with nanofluidic systems. among the potential applications of such a combination is the efficient delivery of analyte to the sensor surface. with this in mind, in this work we look to address the challenge of creating and positioning nanoplasmonic sensor elements within nanofluidic pores. a scheme is presented that allpws for the production of arrays of pores in a thin (220nm) silicon nitride membrane with one plasmonic nanoparticle sensor element in each pore. the high throughput fabrication protocol is parallel and enables multiple sensor chips to be produced simultaneously, yet with accurate tuning of the dimension and shape of the nanoparticles. the presented system is shown to possess polarization-sensitive plasmonic resonances that can be tuned significantly in the visible wavelength range by just varying one process parameter. the thickness of the membrane would be optimized to minimize the influence of the optical membrane interference o the plasmonic readout. the sensitivity of the plasmon resonances to changes in refractive index, which forms the basis for using the system for biosensing, was found to be competitive with other nanoplasmonic sensors.
by their very nature, optical fibers and, by extension, intrinsic and extrinsic optical fiberbased sensors are promising devices to be used in very different and complex environments considering their characteristics such as: capabilities to work under strong electromagnetic fields; possibility to carry multiplexed signals (time, wavelength multiplexing); small size and low mass; ability to handle multi-parameter measurements in distributed configuration; possibility to monitor sites far away from the controller; their availability to be incorporated into the monitored structure; wide bandwidth for communication applications. in the case of the optical fibers, the possibility to be incorporated into various types of sensors and actuators, free of additional hazards (i.e. fire, explosion), made them promising candidates to operate in special or adverse conditions as those required by space or terrestrial applications (spacecraft on board instrumentation, nuclear facilities, future fusion installations, medical treatment and diagnostics premises, medical equipment sterilization). major advantages to be considered in using optical fibers/optical fiber sensors for radiation detection and monitoring refer to: real-time interrogation capabilities, possibility to design spatially resolved solutions (the capability to build array detectors), in-vivo investigations (i.e. inside the body measurements).
surface enhanced raman spectroscopy (sers) has the potential to be utilized for the detection of a broad range of chemicals in trace quantities. however, because of the cost and complexity of sers devices, the technology has been unable to fill the needs of many practical applications, in particular the need for rapid, portable, on-site detection in the field. in this work, we review a new methodology for trace chemical detection using inkjet-printed sers substrates on paper. the detection performance of the inkjet-printed sers devices is demonstrated by detecting 1,2-di(4-pyridyl)ethylene (bpe) at a concentration as low as 1.8 ppb. we then illustrate the primary advantages of paper sers substrates as compared to conventional sers substrates. by leveraging lateral flow concentration, the detection limit of paper sers substrates can be further improved. two real-world applications are demonstrated. first, the inkjet-printed sers substrates are used as “dipsticks” for detecting the fungicide malachite green in water. then, the flexible paper-based sers devices are used as swabs to collect and detect trace residues of the fungicide thiram from a surface. we predict that the combination of ultra-low-cost fabrication with the advantages of easy-to-use dipsticks and swabs and the option of lateral flow concentration position ink-jet printed sers substrates as a technology which will enable the application of sers in solving critical problems for chemical detection in the field.
we describe a simple technique for fabricating non-emissive colour filters based on the sensitisation of a highly porous nanostructured metal-oxide film with a monolayer of dye molecules. ultrafast electron transfer at the oxide/dye interface induces efficient quenching of photogenerated excitons in the dye, reducing the photoluminescence quantum yield by many orders of magnitude. the resultant filters exhibit much less autofluorescence than conventional colour filters (where the chromophore is dispersed in a glass or polymer host), and are a viable low cost alternative to interference filters for microfluidic devices and other applications requiring non-emissive filtering.
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