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Novel Ag/TiO <sub/>2</sub> Hierarchical Hollow Spheres Composite with Enhanced Photocatalytic Performance
摘要： Novel Ag nanoparticles and hierarchical TiO2 (Ag/TiO2) hollow spheres composite was prepared via a facile chemical deposition route and their photocatalytic performance in degradation of Rhodamine 6G (R6G) was investigated. The results show that the photocatalytic activity of Ag/TiO2 hierarchical hollow sphere composites is superior to that of pure TiO2 hollow spheres and P25, which is attributed to the unique hollow morphology with high surface area and the reduction of photoelectron–hole pair recombination in TiO2 with the introduction of Ag NPs.
关键词： Ag/TiO2,Hierarchical Hollow Spheres Composite,Photocatalysis
更新于2025-09-10 09:29:36
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Performance of PVDF/TiO<SUB align="right">2 nano-composite film in the application of energy harvester
摘要： The compression mode and shear mode for energy harvesting experimental platform was estabished. The energy collection efficiency of PVDF/TiO2 nano-composite film in the two mode and nonlinear piezoelectric effect were analysed. Experimental results show that the energy collection efficiency of the shear mode was higher than the compressed mode. The Piezoelectric constant and piezoelectric coupling coefficient have nonlinear changes under large stress. In this paper, the experimental data establish a relationship electromechanical coupling coefficients and parameters of composite thin film piezoelectric stress.
关键词： nano-composite film,PVDF,TiO2,energy harvester
更新于2025-09-10 09:29:36
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Fast method for analysing nonlinear composite right/left-handed transmission lines based on finite-difference time-domain method
摘要： In this study, a new finite-difference time-domain (FDTD) scheme is presented for analysing nonlinear composite right/left-handed (CRLH) transmission lines, with reduction of the central processing unit time. A step by step analysis is demonstrated to solve the equations for nonlinear CRLH transmission lines based on the FDTD method. The proposed method is applied to a nonlinear CRLH transmission line as an example and the results are confirmed by those of the conventional FDTD method. The comparisons reveal that the presented solution efficiently decreases by about 82% of the computational time consumption.
关键词： finite-difference time-domain (FDTD),computational time reduction,nonlinear composite right/left-handed (CRLH) transmission lines
更新于2025-09-10 09:29:36
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A compact dual-band bandpass SIW filter using uniplanar combination of the CRLH and resonant type metamaterials
摘要： A new manner of obtaining dual bandpass behaviour in substrate-integrated waveguide (SIW) using a uniplanar combination of composite right/left-handed (CRLH) transmission line and complimentary double split single ring resonator (CDSSRR) is presented and analysed in this paper. The proposed dual band structure has the advantage of miniaturisation due to the presence of both the passbands below the characteristic cuto? frequency of the SIW.A high passband transmission zero overcomes the poor frequency selectivity, and the two resonant frequencies are independently controllable. There are very low insertion losses in both passbands as compared to DGS structures and fabrication simplicity is ensured due to an intact ground. The potential for application of the proposed structure to the design of completely planar miniaturised dual band bandpass metamaterial ?lters has been veri?ed by fabricating a two-stage ?lter based on the proposed combination. The measured results are in good agreement with the simulation results.
关键词： band pass ?lter,complementary split-ring resonators (CSRRs),Metamaterials,Substrate-integrated waveguide (SIW),composite right/left-handed (CRLH),dual-band,miniaturised planar waveguide ?lters
更新于2025-09-10 09:29:36
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Preparation of ZnO nanoparticle-reinforced polyamide 6 composite by <i>in situ</i> -coproduced method and their properties
摘要： Polyamide 6/ZnO nanocomposites (noted as PA6/ZnO) were prepared by an in situ co-producing method, during which Zn2(OH)2CO3 decomposed into nano-ZnO in the process of the opening-ring polymerization of caprolactam at high temperature. Transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry were used to analyze the size and dispersive properties of nano-ZnO, the crystallization and melting properties, the thermal properties, and crystal structure of PA6/ZnO composite, respectively. The results showed that the nano-ZnO derived from Zn2(OH)2CO3 via in situ polymerization of PA6-ZnO was uniformly dispersed in PA6 matrix. However, the overall nano-ZnO crystallization rate and crystal size in the PA6 matrix were hindered by the bulky PA6 molecular chains. The mechanical properties were evaluated using universal tensile and impact testing instruments. The results revealed that PA6/ZnO composite with 0.2% nano-ZnO content possessed excellent tensile strength, enhanced by 75% in comparison with the pure PA6. The nano-ZnO had little influence on the impact strength of PA6.
关键词： friction property,mechanical performance,nanocomposites,polyamide 6,nano-ZnO,polyamides,composite
更新于2025-09-09 09:28:46
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Thermal behaviour of poly(methyl methacrylate)/fullerene composite films
摘要： Poly(methyl methacrylate)/fullerene composite films were fabricated by casting from toluene solutions. The mass fraction of fullerene (C60) was varied from 0.05–3 wt. %. The effect of the fullerene (C60) content on the thermal degradation parameters of the composite films was evaluated by thermogravimetric (TG) analysis. It was found that the incorporation of C60 improved the thermal stability of the polymers. The films eventually decomposed in three stages. Incorporation of fullerene caused a change in the distribution of mass loss over the stages of degradation in comparison with the pristine polymer. Using differential scanning calorimetry (DSC), the phase transitions from the glassy state to the elastic one was studied for the examined polymeric materials. New data relating to the effect of C60 on the glass transition temperature of composites with low weight fractions of filler were obtained. Specifically, for films containing up to 0.1 wt. % of C60, a single glass transition temperature was found, whereas for composites with a higher concentration of filler, two glass transition temperatures were recorded.
关键词： Composite materials,thermogravimetric (TG) analysis,glass transition,DSC,fullerenes,thermal stability
更新于2025-09-09 09:28:46
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Analysis of Second-Harmonic Generation of Low-Frequency Dilatational Lamb Waves in a Two-Layered Composite Plate
摘要： We analyze the effect of second-harmonic generation (SHG) of primary Lamb wave propagation in a two-layered composite plate, and then investigate the influence of interfacial properties on the said effect at low frequency. It is found that changes in the interfacial properties essentially affect the dispersion relation and then the maximum cumulative distance of the double-frequency Lamb wave generated. This will remarkably influence the efficiency of SHG. To overcome the complications arising from the inherent dispersion and multimode natures in analyzing the SHG effect of Lamb waves, the present work focuses on the analysis of the SHG effect of low-frequency dilatational Lamb wave propagation. Both the numerical analysis and finite element simulation indicate that the SHG effect of low-frequency dilatational Lamb wave propagation is found to be much more sensitive to changes in the interfacial properties than primary Lamb waves. The potential of using the SHG effect of low-frequency dilatational Lamb waves to characterize a minor change in the interfacial properties is analyzed.
关键词： composite plate,interfacial properties,low frequency,second-harmonic generation,Lamb waves
更新于2025-09-09 09:28:46
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POWER PERFORMANCE AND SPURIOUS FREQUENCIES ANALYSIS OF COMPOSITE RIGHT-/LEFT-HANDED (CRLH) DISTRIBUTED OSCILLATORS
摘要： This paper concerns the analysis of the performance of a Composite Right-/Left-Handed (CRLH) distributed oscillator. In order to increase its output power, a modification of the standard configuration is proposed. The basic idea is to combine the signals from the two output ports of the structure by means of a Wilkinson combiner, so obtaining a single output generator. The power performance of the conventional two output oscillator and the power performance of the new configuration are numerically compared by changing the number of employed transistors. The same procedure is adopted to analyze the amplitude of the higher order harmonics in the generated signals as a function of the number of active elements. On the basis of simulated data an increase of the output power, together with a second harmonic reduction, is expected for the single output oscillator with respect to the standard CRLH topology. Experimental results fully confirm these numerical predictions.
关键词： output power,Composite Right-/Left-Handed (CRLH),Wilkinson combiner,harmonics,distributed oscillator
更新于2025-09-09 09:28:46
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Compositing Two-Dimensional Materials with TiO2 for Photocatalysis
摘要： Energy shortage and environmental pollution problems boost in recent years. Photocatalytic technology is one of the most effective ways to produce clean energy—hydrogen and degrade pollutants under moderate conditions and thus attracts considerable attentions. TiO2 is considered one of the best photocatalysts because of its well-behaved photo-corrosion resistance and catalytic activity. However, the traditional TiO2 photocatalyst suffers from limitations of ineffective use of sunlight and rapid carrier recombination rate, which severely suppress its applications in photocatalysis. Surface modification and hybridization of TiO2 has been developed as an effective method to improve its photocatalysis activity. Due to superior physical and chemical properties such as high surface area, suitable bandgap, structural stability and high charge mobility, two-dimensional (2D) material is an ideal modifier composited with TiO2 to achieve enhanced photocatalysis process. In this review, we summarized the preparation methods of 2D material/TiO2 hybrid and drilled down into the role of 2D materials in photocatalysis activities.
关键词： TiO2,composite,2D materials,photocatalysis
更新于2025-09-09 09:28:46
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PHASE ENHANCEMENT FOR MULTI-RESONANCE COMPACT METAMATERIAL ANTENNAS
摘要： In this paper, a nonlinear phase enhancement of multi-resonance composite right/left-handed unit cell for multi-band antennas is presented. Di?erent antennas with nonlinear enhanced phase which can operate up to ?ve di?erent frequency bands are introduced. Meanwhile, the proposed antennas have compact size so that they can demonstrate size reduction up to 60% compared to conventional patch antennas operating at the same frequencies. The achieved phase enhancement has been validated by comparing two di?erent con?gurations of composite right/left-handed cells. The analysis, electromagnetic full wave simulations and experimental results are discussed. A reasonable agreement is achieved between the measured and simulated results.
关键词： compact metamaterial antennas,phase enhancement,composite right/left-handed (CRLH),multi-resonance,multi-band
更新于2025-09-09 09:28:46