- 标题
- 摘要
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- 实验方案
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Quantitative cosmetic evaluation of long-lasting foundation using multispectral imaging
摘要： Background: We tried to search appropriate wavelength to quantitatively evaluate the ability of long- lasting foundation using a hyperspectral imager (HSI) which can simultaneously measure position and wavelength information. Materials and methods: A good reputable long- lasting foundation was applied to the skin of 10 healthy volunteers. Their skin was measured by our newly developed HSI every 2 hours from immediately after application to 6 hours. The application state of the foundation was quantified using the standard deviation of reflectance. Results: A high correlation between standard deviation and the application state of the foundation was confirmed at many wavelengths. In particular, it was suggested that by using the standard deviation of 800 nm, the application state of the foundation can be evaluated quantitatively without depending on the subject’s oxygen saturation level. Conclusion: By quantitatively evaluating the cosmetic- applied skin by our system, further efficiency improvement of the volunteer experiment is expected.
关键词： cosmetic evaluation,spectrum analysis,long-lasting foundation,hyperspectral imaging
更新于2025-09-23 15:23:52
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In Situ Formed Gradient Bandgapa??Tunable Perovskite for Ultrahigha??Speed Color/Spectruma??Sensitive Photodetectors via Electrona??Donor Control
摘要： Integration of various photodetectors with different light-sensitive materials and detection capacity is an inevitable way to achieve entire color/spectrum detection. However, the uneven capacity of each photodetector would drag the overall performance behind, especially the response speed. A response time down to nanosecond level has not previously been reported for a filter-free color/spectrum-sensitive photodetector, as far as is known. Here, a self-powered filterless color-sensitive photodetection array based on an in situ formed gradient perovskite absorber film with continuously tunable bandgap is demonstrated. Ultrahigh-speed response at nanosecond level is achieved in all the ingredient photodetectors. The junction capacitance being influenced by carrier concentration in the absorber is identified to be responsible for the detection speed. Without any optic or mechanical supporting system, the designed color detector exhibits an external quantum efficiency (EQE) up to 94% and a high spectral resolution of around 80 nm for the whole visible spectrum. This work offers a guidance to achieve fast response of perovskite-based photodetectors from the point of view of carrier-donor control and demonstrates a new avenue to establish color-sensitive photodetectors/spectrometers.
关键词： photodetectors,self-powered devices,color-sensitive photodetection,spectrum analysis,perovskites
更新于2025-09-23 15:19:57
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High sensitivity sensing system theoretical research base on waveguide-nano DBRs one dimensional photonic crystal microstructure
摘要： In this paper, we propose a novel wavelength modulation system dedicated to improve the performance of the integrated silicon microsensor. This system includes light source, waveguide, distributed Bragg reflectors (DBRs) and optical spectrum analyzer. Here, the silicon waveguide and two nano DBRs were designed to be one dimensional photonic crystal structure, which can implement wider modulation range in the photonic band gap. The rigorous coupled wave analysis (RCWA) method was used to quantitatively calculate transmissivity of each wavelength photon, and then spectral data in different displacement were obtained. By analyzing the defect modes in the spectrum, typical performance indicators of this modulation system are demonstrated as follows: The wavelength defect mode can be modulated from 1.2 μm to 2.7 μm, corresponding displacement is from 0 to 1.5 μm; System sensitivity is up to 1.23-1.41, linearity ranges from 0.99 to 0.9999 for order 1 defect mode; The minimum peak transmittance of defect mode is greater than 0.68 based on 1 pm wavelength calculated step. Compared with the same type of system reported, the performance indicators have obvious advantages, and it is expected to directly improve the sensor performance by combining with the existing micro-mechanical structure.
关键词： Optical instruments,Optical spectrum analysis,Optical systems,Optical design of instruments
更新于2025-09-23 15:19:57
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FOG De-Noising Algorithm Based on Augmented Nonlinear Differentiator and Singular Spectrum Analysis
摘要： A novel algorithm based on singular spectrum analysis (SSA) and augmented nonlinear differentiator (AND) for extracting the useful signal from a noisy measurement of fiber optic gyroscope (FOG) is proposed in this paper. As a novel type of tracking differentiator, augmented nonlinear differentiator (AND) has the advantages of dynamical performance and noise-attenuation ability. However, there is a contradiction in AND, i.e., selecting a larger acceleration factor may cause faster convergence but bad random noise reduction, whereas selecting a smaller acceleration factor may lead to signal delay but effective random noise reduction. To overcome the contradiction of AND, multi-scale transformation is introduced. Firstly, the noisy signal is decomposed into components by SSA, and the correlation coefficients between each component and original signal are calculated, then the component with biggest correlation coefficient is reserved and other components are filtered by AND with designed selection criterion of acceleration factor, finally the de-noising result is obtained after reconstruction process. There are mainly two prominent advantages of the proposed SSA-AND algorithm: (i) Compared to traditional tracking differentiators, better de-noising ability can be achieved without signal delay; and (ii) compared to other widely used hybrid de-noising methods based on multi-scale transformation, a parameter determination method is given based on the correlation coefficient of each decomposed component, which improves the reliability of the proposed algorithm.
关键词： fiber optic gyroscope,augmented nonlinear differentiator,de-noising,singular spectrum analysis
更新于2025-09-19 17:15:36
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Simultaneous Measurements of Light Hydrocarbons Using Supercontinuum Laser Absorption Spectroscopy
摘要： Simultaneous measurements of light hydrocarbon species based on near-infrared (near-IR) supercontinuum laser absorption spectroscopy (SCLAS) are demonstrated. SCLAS is a broadband absorption diagnostic technique that provides significant advantages over existing absorption diagnostic techniques. Coupled with a fast spectrum analysis strategy, accurate measurements of multiple hydrocarbon concentrations can be made concurrently. Methane (CH4), acetylene (C2H2), ethylene (C2H4), and their mixtures were probed near ambient temperature and pressure conditions. Light hydrocarbons are found in many fuel and energy applications, and a sensor that can accurately and simultaneously probe multiple species’ concentrations and temperature would greatly enhance measurement versatility. Absorption spectra of the three hydrocarbon species were measured between 1.5 and 1.7 μm in this study. These spectra can be very convoluted, where broad absorption features interfere with neighboring features, be it from the same or different species. Species concentrations and temperatures were resolved using a spectrum analysis strategy based on linear regression. Experimental results showed good agreement with test conditions even in the presence of significant spectral overlap.
关键词： supercontinuum laser absorption spectroscopy,light hydrocarbons,spectrum analysis strategy,simultaneous measurements,near-infrared
更新于2025-09-19 17:13:59
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Optical Spectrum Measurement and Analysis for Flexible WDM System Using Faster R-CNN-based Object Detection
摘要： An optical spectrum measurement and analysis method using faster R-CNN-based object detection technique is proposed. This method can simultaneously analyze OSNR, bandwidth, and center wavelength of FWDM system. The average accuracy reaches 98.6%.
关键词： Optical performance monitoring,Object detection,Optical spectrum analysis
更新于2025-09-16 10:30:52
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Josephson Arbitrary Waveform Synthesizer as a Reference Standard for the Measurement of the Phase of Harmonics in Distorted Signals
摘要： We use the Josephson arbitrary waveform synthesizer to provide traceability for the phase of the harmonics, relative to its fundamental, of a distorted waveform. For distorted waveforms with rms values in the range from 0.154 V to 0.2 V and harmonic magnitudes from 5% to 40 % of the fundamental, our system can generate odd harmonics up to the 39th with phase uncertainties from 0.002° to 0.010° (k=2.0), depending on the harmonic number and harmonic magnitude.
关键词： Josephson junction array,measurement techniques,measurement quantum voltage standards,standards,phase measurement,spectrum analysis
更新于2025-09-10 09:29:36
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?Lab on a Chip“; Lab on a Chip;
摘要： Background. Miniaturization has not only driven microelectronics and generated new unforeseen options but has also dramatically changed sensors and analytics. Developments. The Lab on a Chip (LOC) technology enables laboratory processes to run fully automated in canals in the micrometre range. The biggest challenge for LOC is to keep production costs low despite miniaturization and application-specific design. If this is achieved medical laboratory analyses can usually be carried out faster and with less hands on time. This explains why LOCs are already integrated into many laboratory instruments and why point-of-care testing (POCT) can no longer be imagined without it. New markers, such as in liquid biopsies and measurement techniques, such as Raman spectroscopy and mass spectroscopy, create further potentials that will enable faster and more specific laboratory analyses to be made using LOC technology. Conclusion. The LOC technology has the potential of changing the medical practice especially in cases when the central laboratory is not available or is unable to provide results fast enough.
关键词： Laboratory diagnostics,Mass spectrometry,Point-of-care testing,Spectrum analysis, Raman,Microfluidics
更新于2025-09-10 09:29:36
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Environmentally-friendly technology for rapid on-line recycling of acrylonitrile-butadiene-styrene, polystyrene and polypropylene using near-infrared spectroscopy
摘要： The recovery of waste acrylonitrile-butadiene-styrene (ABS), polystyrene (PS) and polypropylene (PP) from waste white goods was inefficient due to their similar chemical and physical property. In this work, an environmental friendly equipment based on on-line dynamic recognition for recycling the waste white goods plastic stream (i.e. ABS, PS and PP mixture) was established. It included the recognition process utilizing the near infrared (NIR) range 1050nm-1350nm and separation process using the air ejection. In particular, NIR spectrum of waste plastic stream were acquired on-line and analyzed dynamically with the self-designed software. Results showed that although ABS, PS and PP share very similar chemical and physical property, it is possible to separate them with a high accuracy up to 99%. Meanwhile, the optimized operating parameters of the separation process were studied to guide the further industrial recycling process. The study revealed the potentiality of NIR technique as mechanical methods in recycling of plastics from the waste white goods.
关键词： on-line recognition,plastic separation,plastic recycling,NIR spectrum analysis
更新于2025-09-04 15:30:14
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Extracting Displacement and Strain Fields from Checkerboard Images with the Localized Spectrum Analysis
摘要： The performance of white-light full-field measurement methods strongly depends on the nature of the pattern used to mark the surface on which displacements and strains are measured. Finding optimized patterns is therefore a topical question. The aim of this study is to examine the case of the checkerboard pattern. It is first shown that this periodic pattern can be processed with a Fourier-based technique such as LSA. Experiments are then carried out to compare the noise level in displacement and strain maps obtained by processing classic 2D grid and checkerboard images. The conclusion is that the noise level observed in displacement and strain maps is significantly lower with a checkerboard than with a classic 2D grid. A notched specimen is finally tested to illustrate that very low strain levels can be measured with checkerboard patterns.
关键词： Grid method,Checkerboard,Localized spectrum analysis,Optimal pattern,Digital image correlation,Heteroscedastic noise,Metrology,Pattern optimization,Windowed Fourier transform
更新于2025-09-04 15:30:14