ANNALEN DER PHYSIK
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2021
·Vol. 533
·期 2
·2000464
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IF 2.987
Xinxi Zeng,Han Zhang,Xiaoqing Xi,Bo Li,Ji Zhou
The terahertz (THz) spectral range offers a platform for experimentally collecting electromagnetic pulses to analyze the intrinsic resonances of matter and has become an important field for applying intrinsic responses to future information devices. However, a lack of numerical methods for signal denoising exists in the knowledge of the THz spectral range. In this paper, numerical methods that employ the Bézier curve and its generalization ( B -spline) to denoise thermally tunable and thickness-dependent terahertz signals are proposed. Different thicknesses of ErFeO 3 are chosen and prepared. Both Bézier curves and B -splines have the ability to denoise the signals and the effect of the Bézier curves on the noise is close to but slightly less than that of the B -splines. Additionally, the B -splines show a better noise reduction effect and have better signal strength stability and robustness than do the Bézier curves. Thus, B -splines are applied to process the raw data, and quantitative insight into the trend of the resonant frequencies, peak heights, and transmittances of antiferromagnetic resonance and ferromagnetic resonance with temperature is obtained.
研究领域:
物理学
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材料科学
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DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2021
·Vol. 104
·期 7
·3325-3333
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IF 3.784
Xinxi Zeng,Yuhe Liang,Han Zhang,Xiaoqing Xi,Jianguo Cao,Bo Li,Ji Zhou
Rare-earth orthoferrites with weak ferromagnetism have become one of the most fascinating topics in antiferromagnet research because of their potential application in future information technologies. However, an appropriate and direct way to reduce the noise in the intrinsic but weak resonances of rare-earth orthoferrites is currently lacking, creating difficulties in analysis. Here, we report a numerical smoothing method to directly denoise the detected terahertz (THz) responses of orthoferrites using a B -spline algorithm. For comparison, the Savitzky–Golay smoothing method, which is a typical and widely used numerical smoothing method, was also used to process the data. The thickness-dependent signals of DyFeO 3 were processed by the above methods. LaFeO 3 , HoFeO 3 , and DyFeO 3 were chosen and prepared, and their thermally tunable signals were processed. The B -spline signal smoothing algorithm was shown to have stability and robustness to noise and was more effective than the Savitzky–Golay smoothing method at reducing noise. This work on smoothing thickness- and temperature-dependent THz signals may help provide a promising approach to reduce noise in the intrinsic but weak resonances of rare-earth orthoferrites.
研究领域:
物理学
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材料科学
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DOI
高影响因子
APPLIED OPTICS
·
2017
·Vol. 56
·期 20
·5698-5704
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IF 1.65
Y. Huang,P. Sun,Z. Zhang,C. Jin
Water vapor noise in the air affects the accuracy of optical parameters extracted from terahertz (THz) time-domain spectroscopy. In this paper, a numerical method was proposed to eliminate water vapor noise from the THz spectra. According to the Van Vleck–Weisskopf function and the linear absorption spectrum of water molecules in the HITRAN database, we simulated the water vapor absorption spectrum and real refractive index spectrum with a particular line width. The continuum effect of water vapor molecules was also considered. Theoretical transfer function of a different humidity was constructed through the theoretical calculation of the water vapor absorption coefficient and the real refractive index. The THz signal of the Lacidipine sample containing water vapor background noise in the continuous frequency domain of 0.5–1.8 THz was denoised by use of the method. The results show that the optical parameters extracted from the denoised signal are closer to the optical parameters in the dry nitrogen environment.
研究领域:
物理学
·
光谱学
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DOI
PubMed
高影响因子
OPTICS AND LASER TECHNOLOGY
·
2025
·
IF 5
Fengtong Zhu,Kun Liu,Jianying Jing,Lu Xiao,Xiaohan Zhan,Jinchang Liu,Yiyang Xiong,Junfeng Jiang,Tianhua Xu,Shuang Wang,Tiegen Liu
A SnS 2 -polydopamine (PDA) enhanced nearly guided-wave surface plasmon resonance (NGW-SPR) refractive index (RI) probe with high sensitivity and high-resolution has been proposed. For the first time, we systematically analyze the high-resolution demodulation methods for the optical fiber SPR sensor in terms of the wavelength resolution of the sensing system, rather than the spectrometer parameter. The sensor resolution is improved by increasing the sensor sensitivity and reducing the standard deviation of the resonance wavelength monitoring values. Taking advantage of the popular thermoelectric material SnS 2 with high carrier mobility and PDA with mussel adhesion properties, the composite material SnS 2 -PDA can effectively improve the sensitivity of the RI probe. To ensure accurate and high-resolution extraction of the SPR resonance wavelength, a wavelet packet denoising demodulation algorithm based on the self-calibrating polynomial fitting is developed. Experimental results demonstrate that the average sensitivity of the proposed RI probe achieves up to 3191.61 nm/RIU within the range of 1.3330 ∼ 1.3560 RIU. The probe offers a resolution of 3.47 × 10 −5 RIU, which is 1 ∼ 2 orders of magnitude higher than previously reported RI sensors. The proposed high-resolution NGW-SPR RI probe provides a new idea for the detection of small molecules interaction analysis with low limit of detection (LOD) in biochemistry.
研究领域:
光学传感器
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材料科学
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生物化学
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DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2017
·
IF 1.753
Xiaobin Wang,Wenqian Huang,Qingyan Wang,Chen Liu,Chaopeng Wang,Guiyan Yang,Chunjiang Zhao
This study adopted a Raman hyperspectral imaging system to collect the Raman spectra and hyperspectral images of benzoyl peroxide (BPO) additive for subsequent analysis. The raw Raman spectra of BPO were preprocessed by wavelet denoising. Optimal parameters of wavelet denoising were selected by the orthogonal experimental design. The signal-noise (S/N) ratio of the optimal parameter combination was 32.848. The smoothed Raman spectra were divided into three regions (1900–1300, 1300–700, and 700–100 cm −1 ) for assignment and the band vibrational modes of BPO molecule were obtained. Wherein, the Raman bands at 1771, 1597, 1230, 999, 889 and 845 cm −1 are higher than others, and can be used as the Raman characteristic bands. Analysis of the grayscale images corresponding to different characteristic bands, it is found that the order of change of the image gray level was consistent with characteristic bands intensity. Findings of this study provide the research basics for the detection and analysis of BPO additive.
研究领域:
分析化学
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光谱学
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材料科学
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产品关联
DOI
高影响因子
Laser & Photonics Reviews
·
2025
·
IF 10
Qiang Niu,Jiarui Hu,Han Hao,Rong Zhao,Guling Zhang,Jinfeng Zhu,Yuping Yang
Enhancing the interaction between light and matter, especially at the terahertz band, is pivotal for achieving ultra-broadband trace molecular fingerprint detection. Here, an efficient scheme featuring multiple Fabry–Pérot modes with equal intervals and uniform intensity is presented to implement a resonance interaction enhancement of molecular fingerprints with long-awaited precision and flexibility. This technique constructs uniform resonant probes across the entire spectral range to reveal molecular coupling effects via frequency-selective amplitude attenuation, enabling both qualitative and quantitative detection of L-tyrosine with a detection limit of 0.11 µg mm −2 . This is an inaugural experimental achievement of quantitative THz trace fingerprint detection with dual capabilities of achieving ultra-broadband and high-efficiency. Significantly, the technology enables direct identification of molecular absorption signatures from the transmitted multiple Fabry–Pérot modes using wavelet denoising algorithms, eliminating cumbersome data postprocessing and redundant testing procedures. This advancement heralds a new, accessible era in terahertz fingerprint spectroscopy.
研究领域:
生物物理化学
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分子光谱学
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生物医学工程
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转化医学
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分析化学
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DOI
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2025
·
IF 4.6
Xiulian Yin,Yingjin Li,Mingjie Wei,Yanni Ji,Qinghua Cao,Xiangfen Xue
Spectral retrieval method plays a crucial role in spectral analysis technology. Nevertheless, research in this area has not received the requisite advancement for fluorescence excitation-emission matrix (EEM) spectroscopy, which has been widely used in environmental monitoring and other fields. In this work, we developed a spectral retrieval method, the contour line-based image pattern recognition (CLIPR) technique, to interpret the EEM spectrum. A three-level retrieval mechanism, including the primary feature Lib1, qualitation Lib2 and quantitation Lib3 has been set up. Optimization efforts have been conducted on the accuracy and efficiency of noise removing, feature extraction and image retrieval methods. To demonstrate the technique, four model pollutants with very similar chemical structures and a metal-organic framework (MOF), MOF-74 (Zn), as a fluorescence probe providing more dimensional information were used. A total of 28 × 4 EEM map images were modeled and validated using the leave-one-out cross-validation method. Two batches with 5 × 4 samples each as unknown samples were selected to evaluate the performance of the CLIPR method. When taking the weight value set with 0.8, 0.1 and 0.1, for the validation sets with the concentration greater than 50 μM, the intra class similarity is above 79.61 % and the accuracy reached 98.81 % (83/84). The best quantitative result is PhNH 2 -S1, with the RMSE/True value 3.09 % and R 2 0.99. For the unknown sets, when Batch 1 greater than 35 μM and Batch 2 greater than 50 μM, the recognition accuracy reaches 100 %. The research results indicate that the model has a certain degree of stability and generalization and it is feasible to apply spectral retrieval method to interpret EEM information. We have taken a step forward in laying the foundation for large-scale reference data preparation in this field.
研究领域:
光谱分析
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环境监测
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模式识别
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荧光光谱技术
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化学传感
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产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）