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- 摘要
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- 实验方案
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Red-light Emission of Li-doped Ga2O3 One-dimensional Nanostructures and the Luminescence Mechanism
摘要： Li-doped Ga2O3 one-dimensional nanostructures were synthesized by thermal evaporation. The observation results of morphology show that there are plenty of one-dimensional nanostructures in the sample. Raman spectra of samples show excellent crystallinity and the Raman peaks of the Li-doped Ga2O3 have red-shifted compared to the “undoped” Ga2O3 in the low wavenumber section. Comparing the photoluminescence behavior of the two samples at room temperature, they were found to have blue light emission peaks, but the emission peak of Li-doped Ga2O3 is blue-shifted. Additionally, there is a strong red light emission peak centered at 692 nm in the spectrum of Li-doped Ga2O3.
关键词： Li-doped,Nanostructures,Photoluminescence,Ga2O3,Raman spectrum
更新于2025-09-23 15:23:52
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Design and development of a novel level transmitter utilizing lithium niobate (LiNbO3) Mach-Zehnder modulator for hazardous regions
摘要： In the proposed work, a very low-cost transducer and a novel photonic based transmission technique have developed for liquid level measurement. Two copper parallel plates are used to measure the liquid level in the sensing tube. For transmission of the measured quantity to the remote location, electrical (1–5 V DC), as well as optical technique, has been used. A lithium niobate (LiNbO3) based Mach Zehnder interferometer has been used for the optical transmission. In the proposed method 40GHz, Photline made MXAN-LN-40 light intensity Mach-Zehnder modulator was used. The optical output was analyzed with the help of optical spectrum analyzer (MS9710B) as well as optical meter. Optical transmission was not affected by EMI interference and very advantageous in the inflammable regions. With the help of the proposed method, the sensitivity of 7.02 pF/cm. from the sensor and ?0.236 dBm/cm. from the modulator were achieved. The output of the sensor, signal conditioning, and optically transmitted data has been analyzed experimentally.
关键词： Level transmitter,Optical intensity modulator,Optical spectrum analyzer (OSA),Level sensor,Optical power meter
更新于2025-09-23 15:23:52
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Dynamic spectrum nonlinear modeling of VIS & NIR band based on RBF neural network for noninvasive blood component analysis to consider the effects of scattering
摘要： Dynamic spectrum (DS) is expected to achieve non-invasive analysis of blood components by extracting the absorbance of arterial blood at multiple wavelengths. However, the nonlinearity caused by scattering of blood components is still a factor that limits the detection accuracy. According to the idea of “overlay modeling” in the “M + N” theory, theoretically, the consideration of nonlinear factor in modeling analysis can further improve the prediction accuracy of calibration model. But there is currently no recognized formula to describe this nonlinear relationship. In this paper, the ability of RBF neural network to approximate arbitrary nonlinear functions with arbitrary precision is used to approximate the nonlinear relationship between the spectrum and the component concentration from the perspective of ?tting. The calibration sets and prediction sets were randomly selected from the VIS & NIR band DS data of 231 volunteers, and 10 groups of modeling experiments were carried out. The results showed that compared with the conventional partial least squares (PLS) modeling method, the modeling indicators (correlation coe?cient (R) and root mean square error(RMSE)) of prediction set using radial basis function (RBF) neural network modeling have been signi?cantly improved. The modeling experiments suggest that the nonlinearity caused by scattering should not be ignored in DS non-invasive blood component analysis. By ?tting the nonlinear relationship, RBF neural network can better re?ect the actual mapping relationship between the spectrum and the component concentration, because it can not only consider the general part (Linear factor) in DS, but also the details (Nonlinear factor), which can e?ectively improve the accuracy of the non-invasive blood component analysis based on DS.
关键词： Scattering,Nonlinearity,RBF neural network,Dynamic spectrum (DS),Non-invasive detection
更新于2025-09-23 15:23:52
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Scattering of an Airy light-sheet by a non-spherical particle using discrete dipole approximation
摘要： The scattering of an Airy light-sheet by a non-spherical particle is investigated using the discrete dipole approximation (DDA). The internal and near-surface fields of the cube placed in an Airy light-sheet are calculated, and the effects of the transverse dimension factor w0, the attenuation factor a, and beam center z0 are mainly discussed. w0 can increase the number of side lobes incident on the target, thereby increase the wave jet energy. Increasing the attenuation coefficient a leads to less wave jet energy. By moving the light-sheet, the side lobe of the incident light-sheet increases, and the wave jet energy increases. Potential applications include optical manipulation of particles, particle sizing, optical imaging, etc.
关键词： Scattering,Airy light-sheet,Angular spectrum decomposition method,Discrete dipole approximation (DDA)
更新于2025-09-23 15:23:52
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - High-Frame-Rate Single-Shot Spectrum Measurement for Ultrafast Optical Pulses Based on Optical Signal Processing
摘要： The pulse-by-pulse single-shot spectrum measurement for high-repetition rate optical pulses with femtosecond or picosecond pulse width is important for capturing non-repetitive and rare phenomena of substances. Conventional optical spectrum analyzers cannot acquire the spectrum for each pulse at high-repetition rate without missing due to the low processing speed. Several high-speed optical signal processing techniques can help to acquire pulse-by-pulse single-shot spectrum. The high-speed spectrum measurement using a fiber chromatic dispersion-based time stretch dispersive Fourier Transform (TS-DFT) technique is a powerful tool for such measurements. In this paper, we present a record pulse-by-pulse single-shot spectrum measurement for 1 GHz repetition-rate optical pulses with a less than 67-pm spectral resolution based on the TS-DFT technique.
关键词： time stretch dispersive Fourier Transform,single-shot spectrum measurement,optical signal processing
更新于2025-09-23 15:23:52
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Low-rank Bayesian tensor factorization for hyperspectral image denoising
摘要： In this paper, we present a low-rank Bayesian tensor factorization approach for hyperspectral image (HSI) denoising problem, where zero-mean white and homogeneous Gaussian additive noise is removed from a given HSI. The approach is based on two intrinsic properties underlying a HSI, i.e., the global correlation along spectrum (GCS) and nonlocal self-similarity across space (NSS). We first adaptively construct the patch-based tensor representation for the HSI to extract the NSS knowledge while preserving the property of GCS. Then, we employ the low rank property in this representation to design a hierarchical probabilistic model based on Bayesian tensor factorization to capture the inherent spatial-spectral correlation of HSI, which can be effectively solved under the variational Bayesian framework. Furthermore, through incorporating these two procedures in an iterative manner, we build an effective HSI denoising model to recover HSI from its corruption. This leads to a state-of-the-art denoising performance, consistently surpassing recently published leading HSI denoising methods in terms of both comprehensive quantitative assessments and subjective visual quality.
关键词： Hyperspectral image denoising,Global correlation along spectrum,Full Bayesian CP factorization,Nonlocal self-similarity,Variational Bayesian inference,Tensor rank auto determination
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE 3rd International Conference on Signal and Image Processing (ICSIP) - Shenzhen, China (2018.7.13-2018.7.15)] 2018 IEEE 3rd International Conference on Signal and Image Processing (ICSIP) - A Two-frequency Subtraction Method to Improve Spectral Peak Identifications
摘要： We discuss a two-frequency subtraction technique to reduce the energy leakage in a Fourier spectrum. In our method, frequency components are determined by finding the periodogram over an interval such that the two frequencies will not interfere with each other. Such a method allows the subtraction of the two main frequency components more accurately from the original signal. The energy leakage from the main components is minimized to allow identification and more accurate determination of weaker components. Statistical error from the subtraction technique can be several times smaller than the FFT method. We show that the subtraction method is relatively robust for signals with varying amplitude or frequency.
关键词： time-frequency analysis,Fourier transform,spectrum estimation,spectral leakage
更新于2025-09-23 15:23:52
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The design of a polyaniline-decorated three dimensional W18O49 composite for full solar spectrum light driven photocatalytic removal of aqueous nitrite with high N2 selectivity
摘要： Photocatalysis using solar energy is the most promising green technology for nitrite removal. However, effective photocatalytic performance is often challenged by the limited light absorption, utilization of expensive noble metals and undesired products (nitrate and ammonium). Here, we report for the first time that a full solar light response polyaniline-decorated three dimensional W18O49 composite (PANI@W18O49), a noble metal-free photocatalyst, possesses excellent photocatalytic activity for aqueous nitrite removal with high N2 selectivity. The prepared sample was thoroughly identified via XRD, Raman, FTIR, SEM, TEM, UV–vis DRS and PL. The catalytic results demonstrated that over 80% N2 selectivity (initial concentration 1.0 mM) was achieved through the PANI@W18O49 without sacrificial agent under 300 W Xe lamp irradiation for 60 min. Such advantages were attributed to the built-in junction between n-type W18O49 and p-type PANI, offering suitable redox levels of electron-hole pairs for NO2? reaction. The modification of PANI also benefited the light harvesting ability and activated carriers migration, the calculated rate constant of PANI@W18O49 is about four times as high as that of W18O49. The current study not only prepared a promising photocatalyst, but also provides new insights into improving the photocatalytic activity and N2 selectivity for nitrite treatment.
关键词： Nitrite,Polyaniline,Tungsten oxide,Full solar spectrum light driven,Photocatalysis
更新于2025-09-23 15:23:52
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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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Changes in the IR Spectra of Drinking Water, Melt Water from Snow, and Heavy Water Irradiated by a Nanosecond Electron Beam
摘要： The absorption spectra of drinking water, melt water from snow, and heavy water are studied during irradiation by a nanosecond electron beam. With repeated irradiation of water, a change in the absorption spectrum of the substance was observed. The analysis of water absorption spectra in the IR region shows differences between the absorption spectra of irradiated and nonirradiated water.
关键词： water conductivity,water absorption spectrum in the infrared region,nanosecond electron beam
更新于2025-09-23 15:23:52