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Facile fabrication of well-polarized Bi <sub/>2</sub> WO <sub/>6</sub> nanosheets with enhanced visible-light photocatalytic activity
摘要： Designing a templating strategy for directing mesopore growth along different crystallographic directions is essential for fabricating two- or three-dimensional single-crystalline mesoporous zeolites. However, so far, mesopores formed in MFI zeolites by soft templates have mostly been generated by disrupting growth along the b axis; generating mesopores by disrupting growth along the a axis is rare. Herein, a single-crystalline mesoporous MFI zeolite (SCMMZ) with sheet-like mesopores layered along the a and b axes was synthesized using a triply branched surfactant with diquaternary ammonium groups connected to 1,3,5-triphenylbenzene by a six- and eight-carbon alkyl chain (TPB-6 and 8). The sheet-like mesopores were embedded in the MFI framework and were retained even after calcination. Molecular mechanics calculations provided evidence of low binding energy configurations of the surfactant that directed the growth of straight and zigzag channels along the b and a axes, respectively. The formation of nanosheets was attributed to the geometric matching of the arrangement of the aromatic groups to the zeolite framework.
关键词： mesoporous zeolite,transmission electron microscopy,surfactants,self-assembly,MFI
更新于2025-09-19 17:15:36
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AIP Conference Proceedings [AIP Publishing 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fes, Morocco (25–27 March 2019)] 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Comparison of magnetic field imaging (MFI) and magnetic field simulation of silicon solar cells
摘要： In solar cells, electric currents are generated by electric injection or light flow distributed over the whole area. Each flowing current generates a magnetic field depending on the strength and the direction of the electric current. Recently, a new measuring technology, called magnetic field imaging (MFI) was presented showing the potential to measure the electric current strength and direction by imaging the resulting magnetic fields. The method was applied to various defects, e.g. missing or defect solder point between solar cell interconnector and cross-connector. Here, MFI measurements of various solar cell configurations and solar cell defects are compared with a finite elemental magnetic field simulation. The results are qualitatively and quantitatively interpreted and discussed. The model is used to obtain limits in resolution depending on measuring height and measurable defects (connector brakeage or defect soldering point) of the MFI method. The variation of geometry and material parameters (within reasonable boundaries) on the current flow and the corresponding magnetic field distribution show negligible influence of manufacturing tolerances regarding layer thicknesses and ribbon/connector width as well as material fluctuations resulting in variation of electrical resistance. Measuring height and electrical current have the biggest influence on magnetic field strength and are therefore starting points for process and product optimization.
关键词： magnetic field imaging,FEM,finite element method,MFI,solar cell defects,silicon solar cells
更新于2025-09-16 10:30:52
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A novel modulation format identification based on amplitude histogram space
摘要： In this paper, we proposed a novel modulation format identification method for square M-quadrature amplitude modulation (M-QAM) signals which is based on amplitude histogram space of the incoming data after analog-to-digital conversion, chromatic dispersion compensation at the receiver. We demonstrated the identification of quadrature phase-shift keying (QPSK), 16-QAM, 64-QAM formats with an amplitude histogram space. Simulation results show that it achieve 100% identification accuracy when the incoming signal OSNR is 14 dB to identify the modulation format of QPSK, 16-QAM, and 64-QAM signals in digital coherent systems. The method has low complexity and small delay.
关键词： amplitude histogram space,high-order modulation format,optical performance monitoring,modulation format identification (MFI)
更新于2025-09-10 09:29:36