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TRANSMISSION WINDOW PARTITION MECHANISM IN A FOUR-WAVE MIXING BASED WDM/DWDM NETWORK
摘要： This research work proposes an e?cient four-wave mixing (FWM) based routing and wavelength assignment (RWA) scheme for the improvement of connection blocking probability in WDM/DWDM networks. However, the traditional RWA schemes are less e?cient for the better quality of transmission, and the proposed RWA scheme partitions the entire ?ber transmission window into N number of bands and assigns wavelength randomly from one of the band based on connection length. Finally, the analytical result proves that the mechanism reduces the FWM e?ect signi?cantly in terms of connection blocking probability with higher partition, lower FWM e?ect and better performance.
关键词： connection blocking probability,WDM/DWDM networks,routing and wavelength assignment,four-wave mixing
更新于2025-09-09 09:28:46
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Near-infrared spectra quantitative analysis for flue gas of thermal power plant based on wavelength selection
摘要： This paper proposed a near-infrared (NIR) spectra quantitative analysis method for flue gas of thermal power plant based on wavelength selection. For the proposed method, the self-adaptive accelerated particle swarm optimization is presented for determining the most representative wavelengths of NIR spectral signals and is combined with partial least square for predicting the various contents of the real flue gas dataset. The proposed method chooses the current own optimal or the current global optimal as the reference state randomly and accelerated updates of the flight velocity by the reference state, then the particle state is updated based on the new velocity self-adaptively. The experimental results of a real flue gas dataset verified that the proposed method has higher predictive ability and could overcome the premature convergence.
关键词： near-infrared spectrum,wavelength selection,fuel gas,Thermal power plant,self-adaptive accelerated discrete particle swarm optimization
更新于2025-09-09 09:28:46
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Photocatalytic reduction of uranyl: Effects of organic ligands and UV light wavelengths
摘要： Although previous studies demonstrate the photochemical reduction of uranyl (UO2) in the presence of various organic compounds, the actual roles of organic molecules as ligands and electron donors during the photoreaction are poorly understood. In this study, photochemical reduction of uranyl is examined with respect to organic ligands as electron donors and complexing agents, the role of titanium oxide (TiO2) nanoparticles as a photocatalyst, and the influence of UV light irradiation with emission peaks in the UV-A, UV-B, and UV-C ranges. Organic compounds with different binding affinities to uranyl such as acetate, ethylenediaminetetracetate (EDTA), oxalate, and hydroquinone were selected. Uranyl solutions prepared with one organic compound in a 1:8 molar ratio were irradiated under anoxic and acidic conditions (O2 < 1 ppm, pH 2.5). Uranyl removal by UV irradiation was better than 70 percent in the presence of oxalate and acetate, followed by hydroquinone (≈ 45 %) and EDTA (≈ 10 %). Uranyl removal was nearly constant at the UV-A, UV-B, and UV-C regions in the presence of acetate and oxalate whereas greater removal was observed in the EDTA and hydroquinone solutions exposed to UV-C and UV-A, respectively. These results reveal that uranyl reduction is mediated primarily by TiO2 nanoparticles and is highly dependent on the electron-donor compound. Addition of acetate enhances the uranyl photoreaction in hydroquinone solution. Dissolved EDTA species act as good electron donors at limited EDTA concentrations (1:2 to 1:4 uranyl to EDTA ratios) but at higher concentrations (for example, 1:8), uranyl-EDTA complexes such as [(UO2)HEDTA] compete for the surface sites on the TiO2 nanoparticles, hindering the photoreduction of uranyl. X-ray photoelectron spectroscopy (XPS) of the dried TiO2 powder shows that more than 70 percent of uranium partitioned into the solid phase is present as reduced forms with oxidation states (V) and (IV). The U4f spectra of U partitioned to the solid phase from the photoreaction with acetate reveal the predominance of U(IV) over U(V), whereas U(V) is the dominant oxidation state as a result of the photoreduction with EDTA. Our results suggest that formation of uranium-ligand complexes plays a critical role in controlling the reactivity of uranyl species and the stability of reduced uranium species in the course of the photoreaction.
关键词： organic ligand,rutile,P25,UV wavelength,electron donor,photocatalytic reduction of uranyl,anatase
更新于2025-09-09 09:28:46
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A NEW EQUAL POWER QUADRATURE BRANCH LINE COUPLER FOR DUAL-BAND APPLICATIONS
摘要： We present a new equal power quadrature branch line coupler (BLC) for dual-band applications in this paper. A new topology of the dual-band quarter wavelength transmission lines (TL) with the derivation of design equations is also introduced. The proposed BLC is designed using Advanced Design System (ADS) and fabricated on Rogers 5870 at 0.9 GHz and 2.4 GHz center frequencies. The design approach for the proposed dual-band BLC is endorsed by the simulated and measured results. A comparative analysis of this BLC with the previous BLCs is also carried out.
关键词： Advanced Design System,quarter wavelength transmission lines,equal power quadrature branch line coupler,Rogers 5870,dual-band applications
更新于2025-09-09 09:28:46
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EXTREMELY SUB-WAVELENGTH NEGATIVE INDEX METAMATERIAL
摘要： We present an extremely sub-wavelength negative index metamaterial structure operating at radio frequency. The unit cell of the metamaterial consists of planar spiral and meandering wire structures separated by dielectric substrate. The ratio of the free space wavelength to unit cell size in the propagation direction is record breaking 1733 around the resonance frequency. The proposed metamaterial also possesses the most extreme refractive index of ?109 that has been recorded to date. Underlying magnetic and electric response originate from the spiral and meandering wire, respectively. We show that the meandering wire is the key element to improve the transparency of the negative index metamaterial.
关键词： radio frequency,negative index metamaterial,sub-wavelength,spiral,meandering wire
更新于2025-09-09 09:28:46
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Vis-NIR spectroscopy Combined with Wavelengths Selection by PSO Optimization Algorithm for Simultaneous Determination of Four Quality Parameters and Classification of Soy Sauce
摘要： The performance of Vis-NIR techniques combined with variable select by a simple modified particle swarm optimization (PSO) algorithm for the determination of four quality parameters in soy sauce was evaluated. Compared with full-spectral support vector machine regression (Full-SVMR) and SVMR based on competitive adaptive reweighted sampling (CARS-SVM) method, the application of PSO wavelength selection provided a notably improved SVM regression model. The root-mean-square error of amino acid nitrogen, salt, total acid content, and color ratio obtained by PSO-SVMR are 0.0075 g/100 ml, 0.2176 g/100 ml, 0.0077 g/100 ml, and 0.0506 in predicted sets, respectively. The correlation coefficients of predicted sets obtained by PSO-SVMR reached 0.9997, 0.9462, 0.9996, and 0.9998, respectively. Meanwhile, a classification study constructed with principal component analysis and SVM classification model based on the feature wavelengths selected by PSO shows that Vis-NIR spectra can be used to classify soy sauce according to their brands and quality. The result showed that the Vis-NIR spectroscopy technique based on PSO wavelength selection has high potential to predict the quality parameters in a nondestructive way. This analytical tool may also contribute to the detection of fraud and mislabeling in the soy sauce market and certainly contribute to improvement in quality and reliability of the soy sauce market.
关键词： Quality parameters,Wavelength selection,Modified particle swarm optimization algorithm,Visible and near-infrared spectroscopy,Soy sauce
更新于2025-09-09 09:28:46
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Noninterleaved Metasurface for (2 <sup>6</sup> -1) Spin- and Wavelength-Encoded Holograms
摘要： Nanostructured metasurfaces demonstrate extraordinary capabilities to control light at the subwavelength scale, emerging as key optical components to physical realization of multitasked devices. Progress in multitasked metasurfaces has been witnessed in making a single metasurface multitasked by mainly resorting to extra spatial freedom, for example, interleaved subarrays, different angles. However, it imposes a challenge of suppressing the cross-talk among multiwavelength without the help of extra spatial freedom. Here, we introduce an entirely novel strategy of multitasked metasurfaces with noninterleaved single-size Si nanobrick arrays and minimalist spatial freedom demonstrating massive information on 6-bit encoded color holograms. The interference between electric dipole and magnetic dipole in individual Si nanobricks with in-plane orientation enables manipulating six bases of incident photons simultaneously to reconstructed 6-bit wavelength- and spin-dependent multicolor images. Those massively reconstructed images can be distinguished by pattern recognition. It opens an alternative route for integrated optics, data encoding, security encryption, and information engineering.
关键词： 6-bit hologram,spin-wavelength encoding,multitasked metasurface,Noninterleaved metasurface
更新于2025-09-09 09:28:46
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Granular lesions of short-wavelength and near-infrared autofluorescence in diabetic macular oedema
摘要： Objectives To document and characterise hyper- and hypo-re?ective lesions, which we describe as ‘granular’ on short-wavelength auto?uorescence (SW-AF) and near-infrared (NIR)-AF images in diabetic macular oedema (DMO). Methods Consecutive 103 eyes of 78 patients suffering from centre-involving DMO were reviewed retrospectively. Mosaics of hyper- and hypo-?uorescent dots on both SW-AF and NIR-AF signals were delineated and de?ned as granular lesions in the macula. We evaluated the association of such lesions with the logarithm of the minimum angle of resolution visual acuity (logMAR VA) and spectral-domain optical coherence tomography (SD-OCT) images. Results Diffuse mosaics of hyper- and hypo-?uorescent dots were delineated in 36 and 45 eyes on SW-AF and NIR-AF images, respectively, and both AF images de?ned granular lesions in 33 eyes. These lesions were delineated in both the fovea and extrafoveal areas on NIR-AF images but were limited to the parafoveal and perifoveal sub?elds on SW-AF images. There was a signi?cant difference in logMAR VA between eyes with and without granular lesions (0.358 ± 0.269 vs. 0.185 ± 0.234; P = 0.001). Granular lesions were associated with the mosaic pattern on NIR-AF images (P < 0.001) but not with other parameters on SW-AF and NIR-AF images. The retinal thickness in the central sub?eld was greater in eyes with granular lesions (538.0 ± 163.6 μm vs. 448.8 ± 120.2 μm; P = 0.003). Granular lesions were associated with ELM disruption and hyper-re?ective foci in the outer retinal layers (P = 0.004 and P = 0.037, respectively). Conclusions Granular lesions de?ned on both SW-AF and NIR-AF images were related to retinal oedema with photoreceptor damage and concomitant VA reduction in DMO.
关键词： diabetic macular oedema,photoreceptor damage,near-infrared auto?uorescence,granular lesions,short-wavelength auto?uorescence
更新于2025-09-09 09:28:46
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Studies on Temperature and Strain Sensitivities of a Few-mode Critical Wavelength Fiber Optic Sensor
摘要： This paper studied the relationship between the temperature/strain wavelength sensitivity of a fiber optic in-line Mach-Zehnder Interferometer (MZI) sensor and the wavelength separation of the measured wavelength to the critical wavelength (CWL) in a CWL-existed interference spectrum formed by interference between LP01 and LP02 modes. The in-line MZI fiber optic sensor has been constructed by splicing a section of specially designed few-mode fiber (FMF), which support LP01 and LP02 modes propagating in the fiber, between two pieces of single mode fiber. The propagation constant difference, Δβ, between the LP01 and LP02 modes, changes non-monotonously with wavelength and reaches a maximum at the CWL. As a result, in sensor operation, peaks on the different sides of the CWL then shift in opposite directions, and the associated temperature/strain sensitivities increase significantly when the measured wavelength points become close to the CWL, from both sides of the CWL. A theoretical analysis carried out has predicted that with this temperature/strain sensor approach, the temperature/strain wavelength sensitivities are governed by the wavelength difference between the measured wavelength and the CWL. This conclusion was seen to agree well with the experimental results obtained. Combining the wavelength shifts of the peaks and the CWL in the transmission spectrum of the SFS structure, this study has shown that this approach forms the basis of effective designs of high sensitivity sensors for multi-parameter detection and offering a large measurement range to satisfy the requirements needed for better industrial measurements.
关键词： few mode fiber,temperature sensitivity,In-line Mach-Zehnder interferometer,strain sensitivity,critical wavelength
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE Photonics Conference (IPC) - Reston, VA, USA (2018.9.30-2018.10.4)] 2018 IEEE Photonics Conference (IPC) - Modeling and Analysis of SOI Grating Coupler for Bio-sensing Applications
摘要： This work presents, analysis of SOI optical grating structure operating at 1310 nm wavelength. Power coupling analysis between optical source and grating structure is done. The maximum power coupling efficiency of 55.2% is achieved for 500nm grating pitch having 50% duty cycly on 220nm Si-layer.
关键词： Broadband wavelength,Injection angle,Grating coupler,Multi beam,bio-sensor
更新于2025-09-05 23:14:25