Battas, ManaleEl Jald, El MustaphaSoumahoro, IbrahimaRegragui, Mohammed...
9页
查看更多>>摘要：Herein, structural, and optical properties of the sprayed Zn1-xFexO (ZFO) thin films, with 0 < x < 0.15, have been investigated, by combining experimental characterizations, and theoretical calculations of the light scattering properties. The X-ray diffraction patterns displays a hexagonal wurtzite structure of the polycrystalline films, with c-axis orientation. The iron ions substitution of Zn2+ ions, was confirmed by XRD, Raman and photoluminescence measurements. Furthermore, an obvious redshift in the near band edge emission peak was also observed by photoluminescence analysis which is attributed to the band structure deformation in ZnO thin films. The resulting optical data indicated a strong correlation between the haze factor, crystalline quality, and the surface morphology feature. The scalar scattering theory within the Rayleigh scattering formula, was used to calculate the simulated haze factor, for the two optimized ZFO thin films, through crystalline quality and surface roughness, namely, the synthetized ZFO film with a 5at% and 7at% iron concentration. A good agreement with the scalar scattering theory is obtained, for the haze factor relative to the transmission.
查看更多>>摘要：One of the current trending devices running the market leads to photovoltaic (PV) applications. Their potentials have been well exploited over the years to attain the best output out of them. Moreover, the concept of introducing 2D graphene derivative, graphene quantum dots (GQDs) in such applications is much preferable nowadays, as it has extensive applications in PVs. The performance of PV applications with GQDs is enhanced on contrary to those without GQDs. On that note, several researchers have developed solar cells by applying GQDs either alone or associating with other functionalizing solvents as photoelectrode or any other components obtaining different optical, chemical, structural and electrical characterization results to study the corresponding properties. Hence, the main aim of this paper is based on the comparative study and discussion on these results attained via GQDs and their impact on the performance followed by stating the perspective regarding the yield, efficiency, and future projections, especially focusing on PV applications.
查看更多>>摘要：Inspired by the traditional bulk-boundary correspondence that can be broken by the non Hermitian skin effect, we study the topological properties of the non-Hermitian Su-SchriefferHeeger (SSH) model with spin-orbit coupling (SOC). Considering the relationship of the non Hermitian skin effect and the non-Hermitian Aharonov-Bohm (AB) effect, the topological counterpart is constructed. It finds that the system can be studied in the two subspaces. The analytical forms of the topological invariants are obtained to distinguish different topological phases. The numerical solutions verify the above analysis. The method is expected to apply the system with the non-Hermitian skin effect.
Al-Azzawi, Alabbas A.Almukhtar, Aya A.Hmood, Jassim K.Das, S....
6页
查看更多>>摘要：A broadband amplified spontaneous emission (ASE) source is demonstrated experimentally by using hafnia-bismuth based erbium co-doped fibers (HB-EDFs) with a total length of 200-cm as an active medium. Both of parallel and series configurations are used to generate a broadband ASE source, operating at 1.5 mu m and that cover S-, C-, and L-bands. The comparison proves that the series configuration provides a relatively larger ASE bandwidth, higher output power, higher efficiency, and lower complexity. At the optimum total pumping power of 280 mW, a broadband ASE source of 57 nm with a power ripple of +/- 7.5 dB is achieved. Besides, a total ASE power of 20.8 mW is obtained, which is equivalent to 7% of the pumping efficiency.
查看更多>>摘要：Potential-induced degradation (PID) of photovoltaic (PV) modules is a severe form of degradation in PV modules, where power losses depend on the strength of the electric field, the relative humidity, and temperature. Therefore, understanding how PID influence the performance of PV modules is fundamental to reducing problems caused by such degradation. Previous studies have only considered single effects of PID; however, this work investigates the power losses and the development of hotspots in two different monocrystalline silicon PV modules. The origin of the hotpots is when the examined modules are being affected by severe PID, which results in cracks and materials deterioration. The first module is SiO2-free, and the second module contains this thin film layer. In addition, a PID mitigation procedure of + 1000 V has been applied and its effect examined on the modules. The modules were examined under electroluminescence (EL) and thermal imaging. Following these PID experiments, it was found that the SiO(2 )layer is suitable for deploying commercial PV modules to prevent hotspots and PID. However, applying + 1000 V PID mitigation does not necessarily improve the modules' performance after being affected by PID.
查看更多>>摘要：Herein, a novel high-temperature resistant, miniature all-fiber interferometer is experimentally demonstrated. This interferometer can be formed by an angled fiber without any additional components, which is fabricated by a simple one-step fiber polishing, thus, this angled-fiber based miniature interferometer can serve as a direct sensing probe. The qualitative relationship between fiber interferometer's visibility and fiber angle is calculated by using the coupled mode theory, and this interferometer is experimentally demonstrated, and then, the temperature response and high-temperature resistance of a 39 degrees angled-fiber based interferometer is investigated. The experimental results show that the sensitivity of this 39 degrees angled-fiber interferometer is 13.7 pm/ degrees C in the range of 500-1000 degrees C. Besides, the high-temperature resistance reveals that this all-fiber interferometer excellent high-temperature survivability while the temperature is up to 1000 degrees C.
查看更多>>摘要：In this study, a glucose biosensor based on a hydrogel optical fiber immobilized with a fluorescence indicator and glucose oxidase (GO) is presented. The Hydrogel optical fiber was fabricated by mixing 2-hydroxy-2-methyl-propiophenone as a photo initiator, polyethylene glycol diacrylate (PEGDA) as a base, and deionized water with a certain ratio, irradiated under UV light. The oxygen-sensitive fluorescent indicator, o-phenanthroline ruthenium, and GO were introduced into the core of the hydrogel optical fiber. The sensitivity and efficiency of the system were optimized by varying the concentration of GO and the fluorescent indicator, and the sensing characteristics at different pH and temperatures were investigated. The experimental results showed that the performance of the sensor head was best at 25 degrees C and a pH within the range of 4.5-6. The relationship between the glucose concentration and fluorescence ratio I/I-0 within the range of 20-100 mu g/mL is linear with a correlation coefficient of R-2 = 0.9934. Moreover, the repeatability of the sensing system is good. Due to its good molecular permeability and biocompatibility, a hydrogel optical fiber glucose sensing system can be widely used in biomedical fields.
查看更多>>摘要：Sol-gel method under ultrasonic treatment was utilized to synthesize ZnO/TiO2/ZrO2 ternary nanocomposites. The synthesized samples were characterized using the X-ray diffraction (XRD) analysis, Field Emission Scanning Electron Microscopy (FESEM), UV-VIS, and Photoluminescence (PL) spectroscopy to determine and confirm the successful synthesis of ZnO/TiO2/ZrO2 ternary nanocomposites. The calcination time, aging time, calcination temperature, and duration of ultrasonic irradiation were selected as variable parameters to optimize the nonlinear optical response of nanocomposites under continuous-wave laser irradiation using the Z-scan setup. The results suggest that ZnO/TiO2/ZrO2 ternary nanocomposites with a high third-order nonlinear optical response are potential materials that can be advantageous for photonics application purposes. The application of the statistical analysis shows that the optimum condition for the preparation procedure to achieve the highest nonlinear optical parameters for ZnO/TiO2/ZrO2 ternary nanocomposites can be obtained by selection of a calcination time of 4 h, an aging time of 24 h, calcination temperature of 400 degrees C, and 30 min of ultrasonic irradiation.
查看更多>>摘要：Photon-limited imaging a target hidden behind a scattering medium is a hot technology at present, and it has important applications in many fields. A basic problem is that the target information is annihilated by noise from the speckle captured under weak illumination conditions, which makes it difficult to reconstruct the target. In order to solve this problem, we propose a highly sensitive approach to image through scattering media based on encoding speckles. Under a light level of 0.1 Lux, the target passing through the scattering medium is encoded multiple times by the Gaussian matrix, which can better extract the effective information in speckles. Theoretically, increasing the number of encoding times can improve the ability of information extraction, but also cause time consuming. But our method only needs to encode 39.1% of the full sampling to recover the original target, which effectively improves the encoding efficiency. In addition, Our algorithm has perfect noise resistance, when artificial noise is added to the data , the average peak signal to noise ratio (PSNR) of the algorithm can get 18.16 dB, and the average structural similarity index measure (SSIM) reaches more than 0.65. We also experimentally verify the effects of the algorithm with different network parameters on target reconstruction. The strong reconstruction ability of the proposed method in a low illumination environment can provide a basis for practical application of the proposed method.
查看更多>>摘要：We report symmetric and antisymmetric solitons in the fractional nonlinear Schrodinger equation with the defocused saturable nonlinearity and the PT-symmetric potential. Both symmetric and antisymmetric solitons can exist and maintain their symmetries as the power of the soliton increases. We find that the strong saturable nonlinearity suppresses the change of the propagation constant as the soliton power increases. The stability of symmetric and antisymmetric solitons is studied by the linear stability analysis and also verified by the direct numerical simulation. The results show that the high soliton power and strong saturable nonlinearity can restrain the instability of symmetric solitons, and make symmetric solitons propagate stably and possess strong robustness. However, antisymmetric solitons become very unstable and possess less robust with the increase of the soliton power.
NSTL
Elsevier