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Full-Spectrum Photocatalytic Activity of ZnO/CuO/ZnFe2O4 Nanocomposite as a PhotoFenton-Like Catalyst
摘要： Deriving photocatalysts by the calcination of hydrotalcite-like compounds has attracted growing interest for extending their photocatalytic activity to the visible and even near-infrared (NIR) light regions. Herein, we describe the acquisition of a ZnO/CuO/ZnFe2O4 nanocomposite with good photoFenton-like catalytic activity under UV, visible and near-infrared (NIR) light irradiation by optimizing the calcination temperature of the coprecipitation product of Zn2+, Cu2+ and Fe3+. The ZnO/CuO/ZnFe2O4 nanocomposite is composed of symbiotic crystals of ZnO, CuO and ZnFe2O4, which enable the nanocomposite to show absorption in the UV, visible and NIR light regions and to produce a transient photocurrent in the presence of H2O2 under NIR irradiation. The full-spectrum photoFenton-like catalyst shows improved performance for the degradation of methyl orange with an increasing amount of H2O2 and is very stable in the recycling process. We believe that the ZnO/CuO/ZnFe2O4 nanocomposite is a promising full-spectrum photoFenton-like catalyst for the degradation of organic pollutants.
关键词： ZnO/CuO/ZnFe2O4,photodegradation,Full-spectrum,nanocomposite,photoFenton-like catalyst,near-infrared light,photocatalysis
更新于2025-09-10 09:29:36
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Global Optimization of All-Optical Hybrid-Casting in Inter-Datacenter Elastic Optical Networks
摘要： In inter-datacenter elastic optical networks (IDC-EONs), routing, modulation-level, and spectrum assignment (RMLSA) is one of the key measures to increase network capacity and flexibility of spectrum resource management. The coexistence of unicast, anycast, multicast, and manycast traffic in IDC-EONs forms a more complex network communication scheme called hybrid cast. However, the majority of the previous RMLSA approaches focused on the network communication scheme with single traffic type and optimized network performance on the specific network metric, which leads to less practicability and a limit to one-sided network performance improvement. To achieve better network performance, we investigate the hybrid-cast RMLSA (HC-RMLSA) problem with the objective of improving IDC-EON overall performance. Specifically, a criterion is defined to estimate the overall network performance by considering both the overall network service and operation effectiveness and the network cost. An ILP model is formulated to solve the HC-RMLSA problem under static network scenario. Then, we propose an independent optimization genetic algorithm with priority-based rationality adaption (IOGA-PRA) by coordinating a set of hybrid-cast requests simultaneously to solve the HC-RMLSA problem under both static and dynamic network scenarios. Numerical results show that the performance of IOGA-PRA is very close to the optimal solutions obtained by the ILP model on the network cost-effectiveness in static network scenario. The IOGA-PRA also achieves outstanding improvement of the overall network performance compared with benchmark algorithms in the dynamic network scenario.
关键词： global optimization,hybrid-cast,modulation level,spectrum assignment (RMLSA),inter-datacenter,routing,Elastic optical networks (EONs)
更新于2025-09-10 09:29:36
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Nonlinear process-induced spectral changes in hydrogenated amorphous silicon core optical fibre
摘要： In this paper, the spectral properties of temporal double pulses centred at the same central wavelength and two different central wavelengths are numerically presented based on hydrogenated amorphous silicon core optical fibre. In order to characterise the output spectra of double pulses, the group velocity dispersion and various nonlinear processes including self-phase modulation, cross-phase modulation, two-photon absorption, free carrier absorption and free carrier dispersion are considered in the theoretical model. Numerical results show that, under fixed fibre length condition, the widths of the outcome spectra are strongly dependent on the delay times, peak powers and initial chirps of input double pulses, i.e. widths of the output spectra are proportional to the launched peak powers, and the delay times control the separation between two pulses, resulting in the spectral change within a proper delay time, and the spectral widths are compressed or extended by judiciously adjusting the initial chirps imposed on the input pulses.
关键词： nonlinear processes,optical spectrum,optical fibre,Nonlinear optics,hydrogenated amorphous silicon
更新于2025-09-10 09:29:36
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Fluorescence detection of boscalid pesticide residues in grape juice
摘要： According to the principle of excited fluorescence of organic compounds, the fluorescence properties of boscalid were studied. The mixed system of grape juice and boscalid was studied by fluorescence spectrometer. The fluorescence spectra of different pesticides contents in grape juice were obtained and the relationship between fluorescence intensity and pesticide contentwas analyzed. The results showed that when 292nm was used as the excitation wavelength, there was almost no fluorescence peak in grape juice, and the strong fluorescence characteristic peak of grape juice with boscalid was at 356nm. The prediction model of the content of boscalid in grape juice was obtained by dilution of boscalid in grape juice. The correlation coefficient was 0.9999, the recovery was 98 ~ 105%, the average recovery was 101.7%, and the relative standard deviation was 2.5723%.
关键词： Fluorescence spectrum,Boscalid,Pesticide detection,Grape juice
更新于2025-09-10 09:29:36
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The Analysis of Starlight (Two Centuries of Astronomical Spectroscopy) || The analysis of sunlight: the earliest pioneers
摘要： The story of solar, and hence also of astronomical spectroscopy, began in 1666 when the young Isaac Newton (1642–1726) wrote these famous words: I procured me a Triangular glass-Prisme, to try therewith the celebrated Phaenomena of Colours. And in order having darkened my chamber, and made a small hole in my window-shuts, to let in a convenient quantity of the Suns light, I placed my Prisme at his entrance, that it might thereby be refracted to the opposite wall. [1]
关键词： sunlight,solar spectrum,spectroscopy,Isaac Newton,prism
更新于2025-09-10 09:29:36
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Measurement of Argon emission spectral of ICP plasma using a diagnostic system based on photomultiplier tubes array
摘要： Optical emission spectroscopy (OES) is one of the most important diagnostic tools in plasma physics. A self-built spectroscopic diagnostic system, owning temporal and spatial resolution, has been constructed using photo multiplier tubes (PMTs) array, spectrometer and other parts. The problem of superposition between inlet plane of bundle fiber and the focal plane of the spectrometer is analyzed and solved. In addition, the synchronization regulation of output of PMTs has been completed. This system is installed on an inductively coupled (ICP) plasma chamber in order to study the Argon (Ar) emission spectrum generated from typical radio frequency (RF) and pulse discharges. The test results show that the intensity of Ar emission spectrum increases with the power and pressure, but increase less with the flow and current ratio. Under pulse discharge condition, the intensity of spectrum does not change with the frequency, neither does the broadening of spectrum with time.
关键词： PMTs array,ICP plasma,Argon emission spectrum,Optical emission spectroscopy,RF and pulse discharges
更新于2025-09-10 09:29:36
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Retrieval of absolute SO<sub>2</sub> column amounts from scattered-light spectra: implications for the evaluation of data from automated DOAS networks
摘要： Scanning spectrometer networks using scattered solar radiation in the ultraviolet spectral region have become an increasingly important tool for monitoring volcanic sulfur dioxide (SO2) emissions. Often measured spectra are evaluated using the differential optical absorption spectroscopy (DOAS) technique. In order to obtain absolute column densities (CDs), the DOAS evaluation requires a Fraunhofer reference spectrum (FRS) that is free of absorption structures of the trace gas of interest. For measurements at volcanoes such a FRS can be readily obtained if the scan (i.e. series of measurements at different elevation angles) includes viewing directions where the plume is not seen. In this case, it is possible to use these viewing directions (e.g. zenith) as FRS. Possible contaminations of the FRS by the plume can then be corrected by calculating and subtracting an SO2 offset (e.g. the lowest SO2 CD) from all viewing directions of the respective scan. This procedure is followed in the standard evaluations of data from the Network for Observation of Volcanic and Atmospheric Change (NOVAC). While this procedure is very efficient in removing Fraunhofer structures and instrumental effects it has the disadvantage that one can never be sure that there is no SO2 from the plume in the FRS. Therefore, using a modelled FRS (based on a high-resolution solar atlas) has a great advantage. We followed this approach and investigated an SO2 retrieval algorithm using a modelled FRS. In this paper, we present results from two volcanoes that are monitored by NOVAC stations and which frequently emit large volcanic plumes: Nevado del Ruiz (Colombia) recorded between January 2010 and June 2012 and from Tungurahua (Ecuador) recorded between January 2009 and December 2011. Instrumental effects were identified with help of a principal component analysis (PCA) of the residual structures of the DOAS evaluation. The SO2 retrieval performed extraordinarily well with an SO2 DOAS retrieval error of 1?2×1016 [molecules cm?2]. Compared to a standard evaluation, we found systematic differences of the differential slant column density (dSCD) of only up to ≈ 15 % when looking at the variation of the SO2 within one scan. The major advantage of our new retrieval is that it yields absolute SO2 CDs and that it does not require complicated instrumental calibration in the field (e.g. by employing calibration cells or broadband light sources), since the method exploits the information available in the measurements.
关键词： Fraunhofer reference spectrum,NOVAC,DOAS technique,principal component analysis,volcanic SO2 emissions
更新于2025-09-10 09:29:36
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Vibronic structure and photoelectron angular distribution in the photoelectron spectrum of ICN
摘要： The valence shell photoelectron spectrum of ICN has been simulated using the equation-of-motion coupled-cluster method to calculate the ionization energies and the norms of the Dyson orbitals to describe the intensity of the photoelectron bands. The simulated spectrum not only reproduces the position and intensity of the four main bands observed in the experimental photoelectron spectrum, but the vibronic structure present in the individual photoelectron bands is also reproduced to a reasonable extent. The agreement between the experimental and simulated vibronic structures at higher energies corresponding to the ?A and ?B states is particularly noteworthy. Additionally, the photoionization cross section and asymmetry parameter have been calculated for the ionization of four outermost valence molecular orbitals in the photon energy range of 0–50 eV. The computed asymmetry parameters are found to provide a qualitative description of the corresponding experimental measurements. The shape-resonance seen in the experimental asymmetry parameters and the trends seen in the calculated cross section for the four ionization channels have been explained by the partial wave analysis of the contribution of the individual angular momentum channels to the photoelectron.
关键词： ICN,photoelectron spectrum,vibronic structure,equation-of-motion coupled-cluster method,Dyson orbitals,asymmetry parameter,photoionization cross section
更新于2025-09-10 09:29:36
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-spectra
摘要： Let G be a graph with n vertices, and let A(G) and D(G) denote respectively the adjacency matrix and the degree matrix of G. Define Aα(G) = αD(G) + (1 ? α)A(G) for any real α ∈ [0, 1]. The collection of eigenvalues of Aα(G) together with multiplicities are called the Aα-spectrum of G. A graph G is said to be determined by its Aα-spectrum if all graphs having the same Aα-spectrum as G are isomorphic to G. We first prove that some graphs are determined by their Aα-spectra for 0 ≤ α < 1, including the complete graph Kn, the union of cycles, the complement of the union of cycles, the union of copies of K2 and K1, the complement of the union of copies of K2 and K1, the path Pn, and the complement of Pn. Setting α = 0 or 1/2, those graphs are determined by A- or Q -spectra. Secondly, when G is regular, we show that G is determined by its Aα-spectrum if and only if the join G ∨ Km (m ≥ 2) is determined by its Aα-spectrum for 1/2 < α < 1. Furthermore, we also show that the join Km ∨ Pn (m, n ≥ 2) is determined by its Aα-spectrum for 1/2 < α < 1. In the end, we pose some related open problems for future study.
关键词： Determined by the Aα-spectrum,Aα-spectrum,Join
更新于2025-09-09 09:28:46
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - A Modified Wave Spectrum for Modeling in Remote Sensing Problems
摘要： In this paper we present a new directional spectrum based on both oceanological and remote sensing data. The model is compared with popular ocean wave models used for remote sensing problems of T. Elfouhaily, P.A. Hwang and V. Kudryavtsev. It is shown that the modified wave spectrum is a good choice for L band RCS modeling for moderate incidence angles. It is also shown that the modeling results with the modified wave spectrum are in agreement with experimental data. In a region after spectral peak the model is presented in a form of power-law dependency of spectral density on frequency, where power is different for different wave ranges. It allows carrying out analytical transformations easily. An asymmetrical angular spreading function is used in a spectral model.
关键词： mean square slopes,directional spectrum,remote sensing,ocean surface wave spectrum,radar cross section
更新于2025-09-09 09:28:46