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- 摘要
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- 实验方案
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Dynamic Diffusion of Disperse Dye in a Polyethylene Terephthalate Film from an Infrared Spectroscopic Perspective
摘要： The di?usion behavior of a typical disperse dye, disperse red 9 (DR 9), in the polyethylene terephthalate (PET) ?lm at di?erent temperatures was investigated by attenuated total re?ection?Fourier transform infrared spectroscopy and 2D correlation spectroscopy (2Dcos) analyses. According to the Fickian di?usion model, the calculated di?usion coe?cients of DR 9 in the PET ?lm at di?erent temperatures were observed to increase with temperature, which might be attributed to the increased free volume and thermal motion in the PET matrix and the rapid movement of DR 9 molecules at higher temperatures. In-detail analysis of the di?usion spectra discerned various kinds of molecular interactions, including intramolecular hydrogen bonding interactions of DR 9 and dipole?dipole and π?π interactions between DR 9 and PET. Among these, the dipole?dipole interactions between CO groups of DR 9 and PET occurred ?rst and played a vital role during the di?usion process of DR 9, as deduced from the sequence order of group motions in 2Dcos analysis.
关键词： ATR-FTIR spectroscopy,2D correlation spectroscopy,polyethylene terephthalate,diffusion,disperse dye
更新于2025-09-23 15:19:57
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Mechanical response of a Laser Cladding repaired structure: localization of plastic strain due to microstructure gradient
摘要： Laser Cladding is an additive manufacturing technology enabling to repair complex metallic components by removing the worn region and reconstructing locally the initial geometry. The aim of this work is to study the mechanical response of Inconel 718 repaired thin walls. More precisely, we perform an EBSD imaging and in-situ SEM tensile tests on specimen whose gauge section contains the interface between base material and repaired area. We observe the multiaxial strain patterns until failure at the grain level using a Digital Image Correlation method and superpose this pattern with the microstructure gradient induced by repair. The observations highlight a strain localization phenomenon in repaired structures mainly due to grain size effect.
关键词： SEM tensile tests,Laser Cladding,Inconel 718,strain localization,EBSD,microstructure gradient,Digital Image Correlation
更新于2025-09-23 15:19:57
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Resolution-enhanced imaging using interferenceless coded aperture correlation holography with sparse point response
摘要： interferenceless coded aperture correlation holography (i-coAcH) is a non-scanning, motionless, incoherent digital holography technique. in this study we use a special type of i-coAcH in which its point spread hologram (pSH) is ensemble of sparse dots. With this pSH an imaging resolution beyond the classic diffraction limit is demonstrated. This resolution improvement is achieved due to the position of the coded aperture between the object and the lens-based imaging system. the coded aperture scatters part of the light, that otherwise is blocked by the system aperture, into the optical system, and by doing that, extends the effective numerical aperture of the system. The use of sparse PSH increases the signal-to-noise ratio of the entire imaging system. A lateral resolution enhancement by a factor of about 1.6 was noted in the case of I-COACH compared to direct imaging.
关键词： resolution enhancement,signal-to-noise ratio,interferenceless coded aperture correlation holography,incoherent digital holography,sparse point response
更新于2025-09-23 15:19:57
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Over 10 Gbps VLC for long-distance applications using a GaN-based series-biased micro-LED array
摘要： Our motivation is the design of efficient algorithms to process closed curves represented by basis functions or wavelets. To that end, we introduce an inner-product calculus to evaluate correlations and L2 distances between such curves. In particular, we present formulas for the direct and exact evaluation of correlation matrices in the case of closed (i.e., periodic) parametric curves and periodic signals. We give simplifications for practical cases that involve B-splines. To illustrate this approach, we also propose a least-squares approximation scheme that is able to resample curves while minimizing aliasing artifacts. Another application is the exact calculation of the enclosed area.
关键词： Area,basis functions,correlation,splines,inner product,compact support
更新于2025-09-23 15:19:57
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[IEEE 2020 IEEE Texas Power and Energy Conference (TPEC) - College Station, TX, USA (2020.2.6-2020.2.7)] 2020 IEEE Texas Power and Energy Conference (TPEC) - Performance Evaluation of Photovoltaic Grid-connected Microgrid with Hybrid Energy Storage using Predictive Current Control
摘要： We propose and prove a theorem that allows the calculation of a class of functionals on Poisson point processes that have the form of expected values of sum–products of functions. In proving the theorem, we present a variant of the Campbell–Mecke theorem from stochastic geometry. We proceed to apply our result in the calculation of expected values involving interference in wireless Poisson networks. Based on this, we derive outage probabilities for transmissions in a Poisson network with Nakagami fading. Our results extend the stochastic geometry toolbox used for the mathematical analysis of interference-limited wireless networks.
关键词： interference,Wireless networks,time diversity,correlation,Poisson point process,Nakagami fading,stochastic geometry,Rayleigh fading
更新于2025-09-23 15:19:57
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Low-Loss Waveguide Bends by Advanced Shape for Photonic Integrated Circuits
摘要： A novel quantization watermarking method is presented in this paper, which is developed following the established feature modulation watermarking model. In this method, a feature signal is obtained by computing the normalized correlation (NC) between the host signal and a random signal. Information modulation is carried out on the generated NC by selecting a codeword from the codebook associated with the embedded information. In a simple case, the structured codebooks are designed using uniform quantizers for modulation. The watermarked signal is produced to provide the modulated NC in the sense of minimizing the embedding distortion. The performance of the NC-based quantization modulation (NCQM) is analytically investigated, in terms of the embedding distortion and the decoding error probability in the presence of valumetric scaling and additive noise attacks. Numerical simulations on artificial signals confirm the validity of our analyses and exhibit the performance advantage of NCQM over other modulation techniques. The proposed method is also simulated on real images by using the wavelet-based implementations, where the host signal is constructed by the detail coefficients of wavelet decomposition at the third level and transformed into the NC feature signal for the information modulation. Experimental results show that the proposed NCQM not only achieves the improved watermark imperceptibility and a higher embedding capacity in high-noise regimes, but also is more robust to a wide range of attacks, e.g., valumetric scaling, Gaussian filtering, additive noise, Gamma correction, and Gray-level transformations, as compared with the state-of-the-art watermarking methods.
关键词： quantization watermarking,valumetric scaling,Decoding error probability,normalized correlation,spread transform
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Feasibility Analysis Using Load Profile Modeling Scenarios of Achieving Peak Shaving Using Grid-Tied PV for a Small Utility in Boone, North Carolina
摘要： The distributed Brillouin analysis of an 8.8-km-long fiber with a spatial resolution of 2 cm is presented. All 440 000 potential resolution points are addressed in the measurement. A 7-cm-long hot-spot, located toward the output end of the pump wave, is properly identified in the experiment. The experimental error in the estimate of the local values of the Brillouin frequency shift is ±3.5 MHz. The analysis is based on the simultaneous generation and analysis of Brillouin interaction in more than 2000 correlation peaks, induced by periodic phase modulation of the pump and signal waves. The Brillouin amplifications at individual peaks are resolved using radar-like coding of pump wave magnitude by a 10000 bit-long aperiodic sequence, and postdetection compression at the receiver end. Extensive numerical simulations of the Brillouin interactions over kilometers of fiber with centimeter resolution are reported as well. The results are at the state of the art for high-resolution distributed Brillouin sensors.
关键词： All-optical signal processing,fiber-optic sensors,correlation-domain analysis,stimulated Brillouin scattering,distributed fiber sensors,sequence compression
更新于2025-09-23 15:19:57
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[IEEE 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - Fukuoka, Japan (2019.7.7-2019.7.11)] 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - Progress in InP-based Photonic Integration
摘要： A novel quantization watermarking method is presented in this paper, which is developed following the established feature modulation watermarking model. In this method, a feature signal is obtained by computing the normalized correlation (NC) between the host signal and a random signal. Information modulation is carried out on the generated NC by selecting a codeword from the codebook associated with the embedded information. In a simple case, the structured codebooks are designed using uniform quantizers for modulation. The watermarked signal is produced to provide the modulated NC in the sense of minimizing the embedding distortion. The performance of the NC-based quantization modulation (NCQM) is analytically investigated, in terms of the embedding distortion and the decoding error probability in the presence of valumetric scaling and additive noise attacks. Numerical simulations on artificial signals confirm the validity of our analyses and exhibit the performance advantage of NCQM over other modulation techniques. The proposed method is also simulated on real images by using the wavelet-based implementations, where the host signal is constructed by the detail coefficients of wavelet decomposition at the third level and transformed into the NC feature signal for the information modulation. Experimental results show that the proposed NCQM not only achieves the improved watermark imperceptibility and a higher embedding capacity in high-noise regimes, but also is more robust to a wide range of attacks, e.g., valumetric scaling, Gaussian filtering, additive noise, Gamma correction, and Gray-level transformations, as compared with the state-of-the-art watermarking methods.
关键词： Decoding error probability,valumetric scaling,normalized correlation,spread transform,quantization watermarking
更新于2025-09-23 15:19:57
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Uniformity and isotropy of speckle pattern cause the doubled random error phenomenon in digital image correlation
摘要： For subset-based digital image correlation, the random error of second-order shape function roughly doubles that of first-order shape function, termed doubled random error phenomenon. In this work, we suggest that the fundamental cause of this phenomenon is the uniformity and isotropy of speckle pattern. Specially, we prove that the ratio of random error of second-order shape function to that of first-order shape function, from a view of statistic, is expected to be √7∕2 (≈1.87), which is quite close to the empirical value 2. Numerical experiments demonstrate the correctness of propose theoretical analysis.
关键词： Speckle pattern,Digital image correlation,Random error,Statistical analysis
更新于2025-09-23 15:19:57
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Performance of Localized Coupled Cluster Methods in a Moderately Strong Correlation Regime: H??ckel-M??bius Interconversions in Expanded Porphyrins
摘要： Localized orbital coupled cluster theory has recently emerged as a nonempirical alternative to DFT for large systems. Intuitively, one might expect such methods to perform less well for highly delocalized systems. In the present work, we apply both canonical CCSD(T) and a variety of localized approximations thereto to a set of flexible expanded porphyrins — macrocycles that can switch between Hückel, figure-eight, and M?bius topologies under external stimuli. Both minima and isomerization transition states are considered. We find that M?bius(-like) structures have much stronger static correlation character than the remaining structures, and this causes significant errors in DLPNO-CCSD(T) and even DLPNO-CCSD(T1) approaches, unless TightPNO cutoffs are employed. If sub-kcal mol-1 accuracy with respect to canonical relative energies is required even for M?bius-type systems (or other systems plagued by strong static correlation), then Nagy and Kallay’s LNO-CCSD(T) method with “tight” settings is the suitable localized approach. We propose the present POLYPYR21 dataset as a benchmark for localized orbital methods, or more broadly, for the ability of lower-level methods to handle energetics with strongly varying degrees of static correlation.
关键词： topology interconversions,nondynamical correlation,expanded porphyrins,localized coupled cluster,canonical coupled cluster
更新于2025-09-23 15:19:57