- 标题
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- 实验方案
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Cyclic Microwave-Assisted Metathetic Synthesis and Characterization of Ag-SrWO4/Zeolite Composites
摘要： Silver incorporated SrWO4/zeolite (Ag-SrWO4/zeolite) composites were successfully synthesized by a cyclic microwave-assisted metathetic route followed by heat treatment. The crystallized Ag-SrWO4/zeolite composites were formed at 600 oC for 3 h, showing a well immobilized morphology with particle sizes of 3-5 μm. The synthesized Ag-SrWO4/zeolite composites were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. The optical properties were examined using photoluminescence emission and Raman spectroscopy.
关键词： Cyclic microwave-assisted metathetic synthesis,Ag-SrWO4/zeolite composite,Raman spectroscopy,Photoluminescence
更新于2025-09-09 09:28:46
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DUAL-BAND BANDPASS FILTER USING COMPOSITE COUPLING STRUCTURE FOR CPW/MICROSTRIP
摘要： By using a composite coupling structure for coplanar waveguide (CPW)/microstrip, a new dual-band bandpass ?lter (DBBPF) stacking inverted Y-shaped CPW resonators and rectangular ring resonators is proposed. Two resonant frequency bands are simultaneously excited by the CPW feed line. However, it can be convenient to tune individually. Several transmission zeros are realized to improve the selectivity of the ?lter and achieve wide stopband rejection. Good agreement between simulated and measured results demonstrates the validity of this DBBPF.
关键词： rectangular ring resonators,inverted Y-shaped CPW resonators,composite coupling structure,CPW/microstrip,dual-band bandpass filter
更新于2025-09-09 09:28:46
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Composite spiral zone plate
摘要： A new kind of optical element, i.e., composite spiral zone plate (CSZP), is proposed to generate a twin-vortex beam along the optic axis in this paper. The axial diffraction property of the CSZP is analyzed theoretically and experimentally. The results demonstrate that the CSZP can possess two focused vortices with the same intensity peak, different topological charges, and customized axial positions. The proposed optical device exhibits significant potential for various applications including three-dimensional optical manipulation.
关键词： Composite spiral zone plate (CSZP),Focusing property,Spiral zone plate (SZP)
更新于2025-09-09 09:28:46
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[IEEE 2018 15th European Radar Conference (EuRAD) - Madrid, Spain (2018.9.26-2018.9.28)] 2018 15th European Radar Conference (EuRAD) - Initial Design of Phase-Frequency Scanned Array Using CRLH Leaky-Wave Antennas
摘要： Initial design of phase-frequency scanned array using composite right/left-handed (CRLH) waveguide leaky-wave antennas (LWAs) is studied in this paper. The array consists of 32 frequency scanning CRLH LWAs that are fed by a phased feed system. Two-dimensional (2D) beam steering capability is achieved in the plane normal to the array aperture and verified by the full-wave simulations. This array is capable of scanning to 61° from backward to forward directions in the frequency-scan plane and 17° in the phase-scan plane. The beamwidth is approximately 2° with ?20 dB sidelobe level (SLL) in the frequency-scan plane and 2.5° with maximum ?10 dB SLL in the phase-scan plane. Compared with traditional 2D scanning array, the feed system of this phase-frequency scanned array can be simplified significantly.
关键词： phase-frequency scanned array,leaky-wave antenna (LWA),two-dimensional (2D) beam steering,composite right/left-handed (CRLH),phased array
更新于2025-09-09 09:28:46
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HIGH IMPEDANCE PROPERTIES OF TWO-DIMENSIONAL COMPOSITE RIGHT/LEFT-HANDED TRANSMISSION LINES
摘要： The electromagnetic characteristics of two-dimensional composite right/left-handed transmission lines (2D CRLH TLs) were investigated for the normal incidence of plane waves. The measured characteristic impedance and re?ection phases exhibited resonant high impedance properties (equivalent to zero re?ection phase) at a frequency within the left-handed mode for one-dimensional CRLH TL. An equivalent circuit was proposed to explain the measured characteristics. The relationship between the resonant frequency and the circuit parameters for 2D CRLH TLs was clari?ed by deriving an approximate equation for the resonant frequency.
关键词： equivalent circuit,plane waves,resonant frequency,two-dimensional composite right/left-handed transmission lines,high impedance properties
更新于2025-09-09 09:28:46
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Nanotechnology in Water and Wastewater Treatment || Photocatalytic Decolorization of Two Remazol Dyes Using TiO2 Impregnated Pumice Composite as Catalyst
摘要： This study, as a first attempt, aimed to evaluate photocatalytic decolorization of of two remazol dyes (blue and red) using TiO2 impregnated pumice composite catalyst. The SEM-EDX analysis showed that TiO2 nanoparticules were mostly impregnated on the pores of pumice with a ratio of 1.60% Ti. A 97.8% and 97.6% of color removal was achieved for RB and RR at pH 3, respectively, whereas those color removal percentages decreased to 57.4% and 53.9%, respectively, at pH 11 after 2 hours illumination. The color removal efficiencies of 97.8%, 82.7%, and 75.3% for RB dye and of 97.6%, 85.3%, and 84.0% for RR dye were observed after first, second, and third cycles reuse of the synthesized catalyst. Toxicity of photocatalytic treated samples of both dyes decreased below 50% after 90 and 120 minutes irradiation when they were diluted at 75%. This result indicate there is an urgent need to prolong the irradiation time and/or for increasing catalyst dose to completely remove toxicity in the undiluted samples.
关键词： TiO2 impregnated pumice composite,Remazol dyes,Photocatalytic decolorization,Toxicity,UV-A illumination
更新于2025-09-09 09:28:46
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Novel photocatalytic system Fe-complex/TiO2 for efficient degradation of phenol and norfloxacin in water
摘要： Photocatalysis is one of the effective strategies to eliminate various organic pollutants in water body. In this paper we have prepared a series of new composite photocatalysts to degrade phenol and norfloxacin under visible light irradiation. They were [FeII(dpbpy)2(H2O)2]/TiO2, [FeII(dpbpy)(phen)2]/TiO2 and [FeII(dpbpy)(bpy)2]/TiO2 (dpbpy: 2,2′-bipyridine-4,4′-diphosphoric acid, phen: 1,10-phenanthroline, bpy: 2,2-bipyridyl). The results show that their photocatalytic performance and cyclic stability are much better than that of pure TiO2 or P25. Phenol can be degraded almost completely and the active groups or substituents of norfloxacin (NOR) can be destroyed also, which greatly reduced the biological toxicity of phenol and norfloxacin in water. The possible mechanisms of improving the photocatalytic activity and stability of TiO2 by using Fe-complex are proposed based on free radical capture test and density functional theory calculation. It is clearly that the interfacial interaction between Fe-complex and titanium dioxide directly affects the photocatalytic activity and stability of the composite photocatalyst. The conjugated structure of the complexes plays a crucial role.
关键词： Photocatalystic degradation under visible light,Phenol,Norfloxacin,Fe-complex/TiO2 composite
更新于2025-09-09 09:28:46
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Probing the dielectric, piezoelectric and magnetic behavior of CoFe2O4/BNT-BT0.08 composite thin film fabricated by sol-gel and spin-coating methods
摘要： We investigated in this paper a novel bilayer composite obtained by sol-gel and spin coating of the ferroelectric 0.92Na0.5Bi0.5TiO3–0.08BaTiO3 (abbreviated as BNT-BT0.08) and ferromagnetic CoFe2O4 phases, for miniature low-frequency magnetic sensors and piezoelectric sensors. This heterostructure, deposited on Si-Pt substrate (Si-Pt/CoFe2O4/BNT-BT0.08), was characterized using selected method such as: X-ray diffraction, dielectric spectroscopy, piezoelectric force microscopy, SQUID magnetometry, atomic force microscopy/magnetic force microscopy, and advanced methods of transmission electron microscopy. CoFe2O4/BNT-BT0.08 ferromagnetic–piezoelectric thin films show good magnetization, dielectric constant and piezoelectric response. The results of analyses and measurements reveal that this heterostructure can have applications in high-performance magnetoelectric devices at room temperature.
关键词： ferroelectric,spin coating,ferromagnetic,bilayer composite,magnetoelectric devices,sol-gel
更新于2025-09-09 09:28:46
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Composite GaN-C-Ga (‘GaCN’) Layers with Tuneable Refractive Index
摘要： This article describes novel composite thin films consisting of GaN, C and Ga (referred to as ‘GaCN’, as an analogue to BCN and other carbonitrides) as a prospective material for future optical applications. This is due to their tuneable refractive index that depends on the carbon content. The composites are prepared by introducing alternating pulses of trimethylgallium (TMG) and ammonia (NH3) on silicon substrates to mimic an atomic layer deposition process. Since the GaCN material is hardly reported to the best of our knowledge, a comprehensive characterization is performed to investigate into its chemical nature, primarily to determine whether or not it exists as a single-phase material. It is revealed that GaCN is a composite, consisting of phase-segregated, nano-scale clusters of wurtzitic GaN polycrystals, in addition to inclusions of carbon, nitrogen and gallium, which are chemically bonded into several forms, but not belonging to the GaN crystals itself. By varying the deposition temperature between 400 and 600 oC, and the NH3 partial pressure between 0.7×10-3 and 7.25 mbar, layers with a wide compositional range of Ga, C and N are prepared.
关键词： composite thin films,atomic layer deposition,optical applications,GaCN,tuneable refractive index
更新于2025-09-09 09:28:46
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Redox-Mediated Shape-transformation of Fe3O4 Nanoflake to Chemically Stable Au-Fe2O3 Composite Nanorod for High-Performance Asymmetric Solid-State Supercapacitor Device
摘要： Development of a stable and highly active metal oxide based electrochemical supercapacitor is a major challenge. Herein, we report Au-Fe2O3 nanocomposite having tiny amount of gold (3 atomic % Au) by employing a simple redox-mediated synthetic methodology using modified hydrothermal system. Structural and morphological studies of the synthesized Au-Fe2O3 nanocomposite have been performed both experimentally (XRD, IR, Raman, XPS, TEM and FESEM analyses) and theoretically (WIEN2K). A probable dissolution-nucleation-recrystallization growth mechanism has been suggested to explain the morphological transformation from Fe3O4 nanoflake to Au-Fe2O3nanorod. We have observed the superior chemical stability of Au-Fe2O3 nanocomposite in acidic medium due to composite formation. The electrochemical measurement of the synthesized Au-Fe2O3 nanocomposite exhibits specific capacitance of ~570 F g-1 at the current density of 1 A g-1 in 0.5 M H2SO4 electrolyte. The result is superior compared to the mother component i.e., Fe2O3 (138 F g-1) under identical condition. It is credited to its higher specific surface area and composite effect. Theoretically, decrease in band gap associated with increase in conductivity support the superiority of Au-Fe2O3 nanocomposite compared to the mother compound i.e., Fe2O3. In addition, electrochemical kinetic analysis showed that the charge-storage mechanism is mostly from a dominant capacitive process (78 % at 1.5 mV s-1). Solid-state asymmetric supercapacitor device has been fabricated using synthesized Au-Fe2O3 composite nanorod as positive and activated carbon as negative electrodes. The asymmetric solid-state device exhibits maximum energy density of 34.2 Wh kg-1 and power density of 2.73 kW kg-1 at current densities 1 A g-1 and 10 A g-1, respectively. Thus, the synthesized nanocomposite shows excellent activity as a supercapacitor with long term durability (91% capacitance retention) up to 5000 cycles even in acidic medium.
关键词： Shape-transformation,Redox mediated synthesis,Chemical stability,High power density/energy density,Au-Fe2O3 composite nanorod,Asymmetric supercapacitor
更新于2025-09-09 09:28:46