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Type-II heterojunction constructed by Ag2S-coupled ZnO microspheres with visible light-responsive antibacterial activity
摘要： ZnO nanorods-assembled microspheres were photosensitized with a layer of low bandgap Ag2S nanoparticles on the branched nanorods to get a type-II core/shell heterojunction (ZnO@Ag2S). The heterojunction with unique band configuration exhibited better visible light-responsive antibacterial activity than pure ZnO, which is attributed to the inhibition of photocarrier recombination and efficient charge separation and transfer. Scavenger test confirmed that the photoinactivation of bacteria was directed by the (cid:1) radicals and photogenerated holes. The growth of Gram-negative bacteria was more effectively restrained by ZnO@Ag2S than that of Gram-positive bacteria and fungi because of structural difference of cell walls.
关键词： ZnO@Ag2S,Composite materials,Mechanism,Semiconductors,Photocatalytic activity
更新于2025-09-23 15:21:01
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Preparation of NiO/TiO2 Composite Films for Enhanced Dye Sensitized Solar Cell Efficiency
摘要： Spray pyrolysis technique has been applied for preparing many kinds of thin films because this technique offers a lot of advantages, such as inexpensive cost, uncomplicated process and large scale production. Therefore, the spray pyrolysis technique is used for making pure TiO2 and NiO/TiO2 composite films in this report. A NiO/TiO2 composite film is getting attention to be used as a compact layer in dye sensitized solar cell (DSSC) because NiO can be used as a hole collector and a barrier for energy recombination properties. Moreover, the NiO/TiO2 composite film exhibits superhydrophilic properties that can increase absorption efficiency for a dye solution. This study has an objective to improve the efficiency of DSSC by changing the ratio of NiO/TiO2 in the composite films. The pure TiO2 and NiO/TiO2 composite films were prepared at 200℃ by spray pyrolysis technique using a Ti(OCH(CH3)2)4 solution and a mixture of Ti(OCH(CH3)2)4 solution with Ni(NO3)2?6H2O powder, respectively. The effect of the ratio between Ni(NO3)2?6H2O powder and Ti(OCH(CH3)2)4 solution (0.5 atm%, 1 atm%, 2 atm%, and 4 atm% of Ni(NO3)2?6H2O) on the efficiency of DSSCs were studied. The surface morphology, crystal structure and optical properties of TiO2 and NiO/TiO2 composite films on FTO and glass substrates were characterized by using field-emission scanning electron microscope (FE-SEM), X-ray diffractometer (XRD), and UV-VIS spectrophotometer, respectively. The FE – SEM images showed that the films were smooth surface and dense when prepared at 200 ℃. The XRD results of TiO2 and NiO/TiO2 composite films on the FTO substrates showed that the TiO2 crystals were anatase phase because the peak at 25.30 corresponds to (101) planes of anatase. The spectrophotometer results showed that the optical transmittance for all samples were about 80%. For the energy conversion efficiency characterization, it was found that the NiO/TiO2 composite films that were prepared from 0.5 atm% of Ni(NO3)2?6H2O solution had the better energy conversion efficiency than TiO2 films.
关键词： NiO/TiO2 composite film,Dye sensitized solar cell,Spray pyrolysis technique
更新于2025-09-23 15:21:01
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Mechanistic Origin of the High Performance of Yolk@Shell Bi2S3@N-Doped Carbon Nanowire Electrodes
摘要： High-performance lithium-ion batteries are commonly built with the heterogeneous composite electrodes that combine multiple active components for serving various electrochemical and structural functions. Engineering these heterogeneous composite electrodes toward drastically improved battery performance is hinged on a fundamental understanding of the mechanisms of multiple active components and their synergy or tradeoff effects. Herein, we report a rational design, fabrication, and understanding of yolk@shell Bi2S3@N-doped mesoporous carbon (C) composite anode, consisting of a Bi2S3 nanowire (NW) core within a hollow space surrounded by a thin shell of N-doped mesoporous C. This composite anode exhibits desirable rate performance and long cycle stability (700 cycles, 501 mAhg-1 at 1.0 Ag-1, 85% capacity retention). By in-situ transmission electron microscopy (TEM), X-ray diffraction, and NMR experiments and computational modeling, we elucidate the dominant mechanisms of the phase transformation, structural evolution, and lithiation kinetics of the Bi2S3@C NW anode. Our combined in-situ TEM experiments and finite-element simulations reveal that the hollow space between the Bi2S3-NW core and carbon shell can effectively accommodate the lithiation-induced expansion of Bi2S3-NWs without cracking C shells. This work demonstrates an effective strategy of engineering the yolk@shell-architectured anodes and also sheds light onto harnessing the complex multistep reactions in metal sulfides to enable high-performance lithium-ion batteries.
关键词： multiple computational modeling,lithiation mechanism,in-situ experiments,yolk@shell composite anode,lithium-ion battery
更新于2025-09-23 15:21:01
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In situ synthesis of a cadmium sulfide/reduced graphene oxide/bismuth Z-scheme oxyiodide system for enhanced photocatalytic performance in chlorinated paraben degradation
摘要： An efficient reduced graphene oxide (rGO)-based cadmium sulfide/reduced graphene oxide/bismuth oxyiodide (CdS/rGO/BiOI) Z-scheme system was fabricated by an in-situ growth method. Solid interactions between the rGO and nanoparticles promoted the transmission of photoinduced carriers, which separated and accumulated electrons from CdS and holes from BiOI. Moreover, the Z-scheme system enabled CdS electrons to maintain a high reduction capability and BiOI holes to maintain a high oxidation capability. Therefore, the CdS/rGO/BiOI composite exhibited better photocatalytic activity in the degradation of methyl 3,5-dichloro-4-hydroxybenzoate (MDHB) than that of pure CdS and BiOI under visible light irradiation. In particularly, the identification of active species and transformation products revealed that the accumulated photoinduced electrons promoted the reductive dechlorination of MDHB. The dechlorinated byproducts were then oxidatively split and degraded into harmless small-molecule carboxylic acids or inorganic substances by photoinduced holes. This work provided a favorable in situ growth method to design and synthesize Z-scheme photocatalysts for simultaneous chlorinated paraben dechlorination and degradation under visible light irradiation.
关键词： Dechlorination,Visible light photocatalysis,CdS/rGO/BiOI composite,Z-scheme,Chlorinated paraben
更新于2025-09-23 15:21:01
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Estimation of damage thickness in fibre-reinforced composites using pulsed thermography
摘要： Non-destructive-testing (NDT), including active thermography, has become an inevitable part of composite process and product verification, post-manufacturing. However, there is no reliable NDT technique available to ensure the interlaminar bond integrity during laminates integration, bonding or repair where the presence of thin airgaps in the interface of dissimilar polymer composite materials would be detrimental to structural integrity. This paper introduces a novel approach attempting to quantify the damage thickness of composites (the thickness of air gaps inside composites) through a single-side inspection of pulsed thermography. The potential of this method is demonstrated by testing on three specimens with different types of defect, where the Pearson Correlation Coefficients of the thickness estimation for block defects and flat-bottom holes are 0.75 and 0.85, respectively. This approach will considerably enhance the degradation assessment performance of active thermography by extending damage measurement from currently two dimensions to three dimensions, and become an enabling technology on quality assurance of structural integrity.
关键词： Active thermography,system identification,bonded repair,nonlinear correlation analysis,composite damage detection
更新于2025-09-23 15:21:01
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Wave propagation of the perturbed nonlinear Schr?dingers equation in the nonlinear left-handed transmission lines
摘要： This paper secures chirped dark and bright solitons of the perturbed nonlinear Schr¨odinger equation with parabolic law nonlinearity and self-steepening effect in the nonlinear left-handed metamaterials (NLHMs). We use the ansatz method, sine-cosine, csch function method and the auxiliary equation method to fall out the various soliton solutions. In view of the results obtained, rational, hyperbolic and trigonometric solutions emerge and there are new in CRLH TL. The existence criteria of these solutions are also discussed. Finally, we observed that the use of the auxiliary equation method leads to the abundant and efficient solutions than the other methods.
关键词： integrability,composite right/left-handed transmission lines,Soliton
更新于2025-09-23 15:21:01
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Synthesis, Characterization of SiO2/TiO2 and SiO2/Al2O3 Nano-Composites for the Photo-Degradation of Acid Brown- 43 dye with Irradiation of Solar Light
摘要： In this study we have found that photo degradation of Acid brown- 43 dye with irradiation Solar light Using synthesized SiO2/ TiO2 and SiO2/Al2O3 Nano-composites which prepared by chemical precipitation technique using microwave irradiation. The structure and morphology of SiO2/TiO2 and SiO2/Al2O3) Nano composites were characterized by SEM, EDAX & TEM analysis. The similarities in photo degradation mechanism, SiO2, Al2O3 and TiO2 have as good as band gap energy, and possess worthy standing as photo-catalysts. SiO2/TiO2 and SiO2/Al2O3 nanoparticles have large surface area and thus provide a large number of active sites for interaction among the particles of different oxides. This synthesized Nano-composites of SiO2/TiO2 and SiO2/Al2O3 photo-catalyst sample showed tremendous photo-catalytic activity for the degradation of Acid Blue-43 under direct exposure to solar irradiation with respect to exposed time and dose of Nano-composites.
关键词： Acid brown–43,Photo-degradation,solar irradiation,Nano-composite
更新于2025-09-23 15:21:01
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Exact impact response of multi-layered cement-based piezoelectric composite considering electrode effect
摘要： Multi-layered cement-based piezoelectric composites could enable accurate real-time detection of the concrete structure deformation induced by impact load. An analytical method for quantifying the impact response of the multi-layered cement-based piezoelectric composite is established based on the piezo-elasticity, and a general transfer matrix description for the composite with any number of layers is derived. The motion of the composite is decomposed into natural modes according to its physical significance of vibration modes. The mechanical and electrical solutions are obtained via the mode summation method and the virtual work principle. In order to give a clear demonstration, some numerical simulations are conducted to verify the validity of the theoretical analysis. Moreover, the current analytical method considers the electrode as an extra layer and evaluates the effect of its thickness and material on the performance of the multi-layered cement-based piezoelectric composite. It can be seen that the mathematical model presented in this article provides a rigorous tool for the analysis of the multi-layered cement-based piezoelectric composite and therefore could benefit the design of certain types of smart devices under impact load.
关键词： multi-layered cement-based piezoelectric composite,Exact impact response,piezo-elasticity,electrode effect
更新于2025-09-23 15:21:01
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Poly (Vinyl Alcohol) Decorated Lithium Doped Stannous Oxide Nanocomposites as Highly Flexible UVA Shieldants
摘要： Herein, we report the successful fabrication of a series of mechanically flexible poly (vinyl alcohol) (PVA) nanocomposite films with varying amounts of lithium doped stannous oxide (Li0.4Sn0.8O) nanofillers (i.e., 0.0, 0.5, 1.0, 2.0 and 4.0 wt %) by mechanical shearing followed by film casting. The structural characterizations (FTIR) ascertain the success of lithium doped stannous oxide integrations with PVA matrix. While, electronic spectral studies sheds light on the changes in electronic band structure leading to a gradual decrease in optical band gaps associated electronic transition from valence band to conduction band. The UV-visible transmittance study substantiates the ability of nano fabricated polymeric films to efficiently shield UV radiations, in particular UVA radiations and thereby act as highly flexible and visible transparent UVA protective coatings.
关键词： Lithium doped stannous oxide,UVA protective coatings,Nano composite
更新于2025-09-23 15:21:01
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PERFORMANCE PREDICTION OF BUNDLE DOUBLE-WALLED CARBON NANOTUBE-COMPOSITE MATERIALS FOR DIPOLE ANTENNAS AT TERAHERTZ FREQUENCY RANGE
摘要： In this paper, the double-walled carbon nanotube composite material (DWCNTs-composite) and bundle of DWCNT-composite material (CB-DWCNTs) for antenna applications at terahertz frequency range are presented and investigated. The mathematical modeling and analysis of DWCNTs-composite material is presented for the purpose of modelling and simulation approach. The bundle of DWCNTs-composite material is constructed and designed, based on this modeling approach. The DWCNT-composite material consists of double-walled carbon nanotube coated by a thin jacket of another di?erent material. The dependency of the electrical conductivity of B-DWCNTs-composite on di?erent parameters is presented and investigated. The performance evaluation of B-DWCNTs-composite and CB-DWCNTs materials are presented based on their electromagnetic properties. For this purpose, the dipole antennas of these composite materials are designed and implemented using CST (MWS), where the cross sections of B-DWCNTs-composite and CB-DWCNT materials are circular geometry. Furthermore, comparative studies are performed to show the dependency of size and frequency of the DWCNT-composite material. The results obtained from the DWCNTs-composite and CB-DWCNTs dipole antennas are presented based on S11 parameters, resonant frequency, gain, bandwidth, and e?ciency.
关键词： terahertz frequency,dipole antennas,electromagnetic properties,composite material,double-walled carbon nanotube
更新于2025-09-23 15:19:57