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Technology evolution and long waves: investigating their relation with spectral and cross-spectral analysis
摘要： The present paper is an empirical exercise that contributes to the debate on whether long-lasting cyclical economic development can be viewed as a deterministic phenomenon or a stochastic process. First, we search for longer lasting, periodically reappearing cycles of GDP per capita in four countries: USA, UK, Germany and France. Second, based on theoretical arguments that stress applied knowledge as a significant driving force, we test its dynamic interrelationship with these countries’ economic performance by applying spectral and cross-spectral methodologies. We confirm the existence of periodical long waves both in terms of GDP per capita as well as of applied knowledge. Moreover, we find strong interrelations between them and modest evidence for which is the leading force in the long term.
关键词： applied research,cross-spectral analysis,Long waves
更新于2025-09-23 15:22:29
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[IEEE 2018 China International SAR Symposium (CISS) - Shanghai (2018.10.10-2018.10.12)] 2018 China International SAR Symposium (CISS) - Two Dimensional Image Formation of Interrupted FMCW SAR Through Spectral Analysis
摘要： Most of spaceborne Synthetic Aperture Radar (SAR) systems are based on pulsed mode of operation. Such systems are quite expensive and large sized. Frequency Modulated Continuous Wave (FMCW) based SAR is a light weight and less expensive solution, but the disadvantage is that it requires two antennas – one for transmit and other for receive. Interrupted-FMCW is a recently proposed idea for spaceborne SAR that uses a single antenna for transmission and reception. The main problem of this approach is discontinuity of data in azimuth. This paper proposes a two-dimensional image formation algorithm that uses spectral analysis methods for processing of interrupted-FMCW SAR data. The algorithm has been tested on simulated point target data as well as on a real FMCW data, and the results have been discussed.
关键词： spectral analysis,synthetic aperture radar,interrupted-FMCW,all-pole model,image formation
更新于2025-09-23 15:22:29
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Broad Range and High Precision Self-Mixing Interferometer Based on Spectral Analysis with Multiple Reflections
摘要： In this paper, a novel self-mixing interferometer is proposed with spectral analysis by multiple reflection vibration technique. The relationship between the vibration amplitude, the dominant frequency and the reflection time is deduced, which indicates that the theoretical minimum measurable vibration amplitude is 0.21λ/G(N,θ) and the precision is about 0.08λ/G(N,θ). The displacement sensitivity gain G(N,θ) increases with the reflection time. Theoretical analysis results show that the proposed method for vibration measurement has the advantages of high precision and broad measurement range, especially for the measurement of amplitude much smaller than λ/2. The validity of the method is tested by several experiments with different amplitudes and reflection times. An amplitude of 75 nm has been proved to be measurable and the absolute error is 5.43 nm, which is within the theoretical error range. The proposed method plays an important role in high precision and nanoscale measurement.
关键词： self-mixing,multiple reflections,spectral analysis
更新于2025-09-23 15:21:21
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Quantification of Vortex Generation Due to Non-Equilibrium Electrokinetics at the Micro/Nanochannel Interface: Spectral Analysis
摘要： We report on our investigation of a low Reynolds number non-equilibrium electrokinetic ?ow in a micro/nanochannel platform. Non-equilibrium electrokinetic phenomena include so-called concentration polarization in a moderate electric ?eld and vortex formation in a high electric ?eld. We conducted a spectral analysis of non-equilibrium electrokinetic vortices at a micro/nanochannel interface. We found that periodic vortices are formed while the frequency varies with the applied voltages and solution concentrations. At a frequency as high as 60 Hz, vortex generation was obtained with the strongest electric ?eld and the lowest concentration. The power spectra show increasing frequency with increasing voltage or decreasing concentration. We expect that our spectral analysis results will be useful for micromixer developers in the micromachine research ?eld.
关键词： spectral analysis,concentration polarization,micromixer,Vortex generation,electrokinetics,micro/nanochannel
更新于2025-09-23 15:21:21
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[Springer Series in Optical Sciences] Fano Resonances in Optics and Microwaves Volume 219 (Physics and Applications) || Study of Fano Resonance in the Core-Level Absorption Spectrum in Terms of Complex Spectral Analysis
摘要： We study theoretically the core absorption spectrum of an impurity embedded in a tight-binding chain in terms of complex spectral analysis. The absorption spectral pro?le associated with the resonance states in principle exhibits an asymmetric Fano-type structure, even without apparent multiple interference transition paths. The asymmetric Fano absorption pro?le is attributed to the complex-valued oscillator strength of the transition to the resonance state belonging to the extended Hilbert space. The boundary condition on the continuum causes a large energy dependence of the self-energy, so that it enhances the nonlinearity of the eigenvalue problem of the effective Hamiltonian, yielding several non-analytic resonance states. The optical transitions to these resonance states constitute the overall absorption spectrum structure.
关键词： Fano resonance,core-level absorption spectrum,complex spectral analysis,extended Hilbert space,resonance states
更新于2025-09-23 15:21:21
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[IEEE 2019 SBFoton International Optics and Photonics Conference (SBFoton IOPC) - Sao Paulo, Brazil (2019.10.7-2019.10.9)] 2019 SBFoton International Optics and Photonics Conference (SBFoton IOPC) - Spectral Analysis of a Nanodipole Array above the Surface Impedance of Graphene by Greena??s Function
摘要： In this paper, we present a spectral analysis of a nanodipole array above a graphene layer by the Periodic Green’s Function (PGF) method. The graphene layer deposited on a dielectric substrate is modeled as a surface impedance with conductivity described by the Kubo model. The Green’s function is obtained by the complex two-dimensional Fourier series transform, with impedance condition at the interface between the dielectric media. We performed a parametric analysis of the in?uence of chemical potential on the absorbance and the electromagnetic ?elds in the spectral domain. For the modeling used, the dispersion characteristic of graphene is also veri?ed. From the spectral analysis we investigated the emergence of the Surface Plasmon Polariton (SPP) pole in the spectral representation. Finally, we compared the model based on impedance condition with a formulation that considers graphene with a ?nite thickness.
关键词： Spectral Analysis,Plasmonics,Green’s Function,Graphene
更新于2025-09-23 15:21:01
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Investigation of the multi-elemental self-absorption mechanism and experimental optimization in laser-induced breakdown spectroscopy
摘要： The self-absorption effect reduces the accuracy of elements measurement in laser-induced breakdown spectroscopy (LIBS) experiments. In this paper, the mechanism of the self-absorption effect was studied. First, we established a plasma concentration distribution model and plasma dynamics model of the plasma expansion in three directions during LIBS based on physical laws. By coupling a plasma concentration distribution model with a self-absorption model, the LIBS self-absorption effect value model was obtained. Second, the models were applied in a numerical simulation to determine plasma spatial distribution characteristics during LIBS. The self-absorption effect values of spectral lines were calculated. Finally, experiments were conducted with an optical spectrometer to obtain the Na, K, and Al atomic emission spectra. On the theoretical plane, the Boltzmann plot method and the Stark broadening method were used to obtain the plasma characteristic parameters. The spectral line intensities of the Na, K and Al atom lines were obtained without and with microwave-assisted LIBS experiments for comparison. The experimental analysis showed that during the LIBS process, microwave assistance can enhance the emission spectroscopy intensity and inhibit or reduce the LIBS self-absorption effect. The experimental samples were in good agreement with those of theoretical simulation, indicating the effectiveness and practicability of the created LIBS self-absorption effect value model, which can improve the optimization of the LIBS process.
关键词： Self-absorption,LIBS,Numerical simulation,Spectral analysis,Material surface
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - CAOL 2019 Contents
摘要： Manifold learning, especially spectral embedding, is known as one of the most effective learning approaches on high dimensional data, but for real-world applications it raises a serious computational burden in constructing spectral embeddings for large datasets. To overcome this computational complexity, we propose a novel efficient embedding construction, Diverse Power Iteration Embedding (DPIE). DPIE shows almost the same effectiveness of spectral embeddings and yet is three order of magnitude faster than spectral embeddings computed from eigen-decomposition. Our DPIE is unique in that 1) it finds linearly independent embeddings and thus shows diverse aspects of dataset; 2) the proposed regularized DPIE is effective if we need many embeddings; 3) we show how to efficiently orthogonalize DPIE if one needs; and 4) Diverse Power Iteration Value (DPIV) provides the importance of each DPIE like an eigen value. Such various aspects of DPIE and DPIV ensure that our algorithm is easy to apply to various applications, and we also show the effectiveness and efficiency of DPIE on clustering, anomaly detection, and feature selection as our case studies.
关键词： Approximated spectral analysis,power iteration
更新于2025-09-23 15:19:57
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ALK positive lung cancer identification and targeted drugs evaluation using microscopic hyperspectral imaging technique
摘要： It is important to distinguish ALK positive lung cancer from ALK negative lung cancer and to monitor the efficacy of targeted drugs. This paper applies a microscopic hyperspectral imaging technique to identify ALK positive lung cancer cells and evaluate the therapeutic effect. The hyperspectral images of five groups of lung tissues are captured by the home-made microscopic hyperspectral imaging system. A preprocessing algorithm is proposed to reduce obvious banding noise and noise particles from original data. Then a segmentation algorithm, which assembles Supported Vector Machine (SVM) and Majority analysis together with the Clumping processing, is presented. The ALK positive and negative lung cancers can be distinguished by both the fluctuation of spectral curves and the relative proportion between cytoplasm and cell nucleus. In addition, the treatment efficacy can be surveyed in the same way. The experimental results show that the relative proportion of cytoplasm in Group ALK-neg is 77.3%, while that in Group ALK-pos is 40.6%. It is obvious that there exist differences in contents and spectra between Group ALK-neg and Group ALK-pos. Moreover, the experimental results of quantitative analysis and spectral curves analysis show that ALK positive lung cancer cells treated with the low concentration of targeted drugs will be developed towards the ALK negative lung cancer. This paper shows the potential of using hyperspectral images to detect the ALK positive lung cancer cells and evaluate the therapeutic effect of targeted drugs.
关键词： Spectral analysis,Therapeutic effect evaluation,Microscopic hyperspectral imaging,ALK positive lung cancer
更新于2025-09-19 17:15:36
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Absolute continuity of the spectrum in a twisted Dirichlet-Neumann waveguide
摘要： Quantum waveguides with the shape of a planar infinite straight strip and combined Dirichlet and Neumann boundary conditions on the opposite half-lines of the boundary are considered. The absence of the point as well as of the singular continuous spectrum is proved.
关键词： spectral analysis,Quantum waveguides,Mourre theory,Dirichlet-Neumann boundary conditions
更新于2025-09-19 17:13:59