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- 摘要
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- 实验方案
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Synthesis and Consolidation of Nanostructured Nb <sub/>2</sub> C–Al <sub/>2</sub> O <sub/>3</sub> Composite
摘要： Although an extremely hard ceramic material, niobium carbide has low fracture toughness to use wide applications. To fabricate nanostructured composite is common method to improve fracture toughness. Nanopowder mixture of Nb2C and Al2O3 were synthesized according to the reaction from Al4C3 and Nb powders by high-energy ball milling. The synthesized mixture of Nb2C and Al2O3 powders was consolidated by pulsed current activated sintering method within two min under the 80 MPa pressure. Nb2C and Al2O3 in the composite were nano-sized phases. The fracture toughness of a nanostructured Nb2C–Al2O3 composite of this study is better than that of previous study.
关键词： Rapid Sintering,Composite,Mechanical Properties,Nb2C–Al2O3,Nanomaterial
更新于2025-09-23 15:22:29
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Nanoparticle TiO2 size and rutile content impact bioconcentration and biomagnification from algae to daphnia
摘要： Little information is available about effect of particle size and crystal structure of nTiO2 on their trophic transfer. In this study, 5 nm anatase, 10 nm anatase, 100 nm anatase, 20 nm P25 (80% anatase and 20% rutile), and 25 nm rutile nTiO2 were selected to investigate the effects of size and crystal structure on the toxicity, bioconcentration, and trophic transfer of nTiO2 to algae and daphnia. In the exposed daphnids, metabolic pathways affected by nTiO2 and nTiO2-exposed algae (nTiO2-algae) were also explored. The 96 h IC50 values of algae and the 48 h LC50 values of daphnia were 10.3, 18.9, 43.9, 33.6, 65.4 mg/L and 10.5, 13.2, 37.0, 28.4, 60.7 mg/L, respectively, after exposed to nTiO2-5A, nTiO2-10A, nTiO2-100A, nTiO2-P25, and nTiO2-25R, respectively. The bioconcentration factors (BCFs) for 0.1, 1, and 10 mg/L nTiO2 in daphnia ranged from 21,220 L/kg to 145,350 L/kg. The nTiO2 biomagnification factors (BMFs) of daphnia fed with 1 and 10 mg/L nTiO2-exposed algae were consistently greater than 1.0 (5.7-122). The results show that the acute toxicity, BCF, and BMF all decreased with increasing size or rutile content of nTiO2. All types of nTiO2 were largely accumulated in the daphnia gut and were not completely depurated within 24 h. At the molecular level, 22 Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways of daphnia were impacted by the nTiO2 and nTiO2-algae treatments, including glutathione metabolism, aminoacyl-tRNA biosynthesis, among others. Six and four KEGG metabolic pathways were significantly disturbed in daphnids exposed to nTiO2 and nTiO2-algae, respectively, indicating the presence of algae partially alleviated the negative impact of nTiO2 on metabolism. These findings increase understanding of the impacts of physicochemical properties of nTiO2 on the food chain from molecular scale to that of the whole organism, and provide new insight into the ecological effect of nanomaterials.
关键词： Trophic transfer,Bioaccumulation,Algae,Nanomaterial,Water flea
更新于2025-09-23 15:22:29
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Tin Diselenide Molecular Precursor for Solution-Processable Thermoelectric Materials
摘要： In the present work, we detail a fast and simple solution-based method to synthesize hexagonal SnSe2 nanoplates (NPLs) and textured SnSe2 nanomaterials. We also demonstrate that the same strategy can be used to produce orthorhombic SnSe nanostructures and nanomaterials. NPLs are grown through a screw dislocation-driven mechanism. This mechanism typically results in pyramidal structures, but we demonstrate here that the growth from multiple dislocations results in flower-like structures. Crystallographically textured SnSe2 bulk nanomaterials obtained from the hot pressing of these SnSe2 structures display highly anisotropic charge and heat transport properties and thermoelectric (TE) figures of merit limited by relatively low electrical conductivities. To improve this parameter, SnSe2 NPLs are blended here with metal nanoparticles. The electrical conductivities of the blends are significantly improved with respect to bare SnSe2 NPLs, what translates into a three-fold increase of the TE figure of merit, reaching unprecedented ZT values up to 0.65.
关键词： SnSe2,reactive ink,thermoelectricity,crystallographically textured nanomaterial,modulation doping
更新于2025-09-23 15:21:01
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Stepwise Two-Photon-Induced Electron Transfer from Higher Excited States of Noncovalently Bound Porphyrin-CdS/ZnS Core/Shell Nanocrystals
摘要： There has been an increasing amount of interest in stepwise two-photon absorption (2PA)-induced photochemical reactions because of their extremely lower power thresholds compared to that of the simultaneous process and drastic reaction enhancements in some cases. However, stepwise 2PA-induced photochemical reactions were reported only in single chromophores and covalently bound bi-chromophores and there are few reports on these reactions in noncovalently bound systems because of weak electronic interactions among chromophores. This study demonstrated the stepwise 2PA-induced electron transfer from higher excited states in noncovalently bound protoporphyrin IX·CdS/ZnS core/shell nanocrystals (NCs). The electron transfer from higher excited states of porphyrin to CdS NCs successfully overcomes the activation barrier associated with the wide bandgap ZnS shell, indicating that a high reduction potential can be obtained with the stepwise 2PA process. The concept presented in this study can be applied to various noncovalently bound multi-chromophore systems to explore nonlinear photoresponses.
关键词： Nonlinear,Anti-Kasha type,colloidal nanocrystals,hybrid nanomaterial,hot electron transfer
更新于2025-09-23 15:21:01
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Clear observation of the formation of nanoparticles inside the ablation bubble through a laser-induced flat transparent window by laser scattering
摘要： To understand the formation mechanism of nanoparticles via laser ablation in liquids direct observation of the dynamics inside the ablation bubble is essential. One powerful technique for this is small-angle X-ray scattering. Applying the laser-scattering technique in a similar context faces some difficulties, because, firstly the probe laser does not easily go into the bubble due to the curved bubble surface, and secondly the extremely weak scattering signal from inside the bubble is overwhelmed by the very strong reflection at the bubble surface. In this paper we solve those two problems by sending the probe laser into the bubble through a laser-induced flat transparent window, and demonstrate the clean observation of laser-scattering signals from the inside of the ablation bubble. We observe the signature of the formation of nanoparticles around the two areas inside the bubble, i.e., around the central area and apex inside the bubble. The scattering signals originating from the centre of the bubble persist throughout the entire growth and shrinkage stages of the bubble, while practically no scattering signals are found outside the bubble and this clearly implies that almost all nanoparticles are formed inside the bubble. Interestingly, the scattering signals originating from the apex inside the bubble gradually emerge after the bubble reaches the maximum size, and they become brighter as it further shrinks. Those findings are consistent with the scenario of nanoparticle formation obtained by small-angle X-ray scattering experiments.
关键词： nanomaterial synthesis,light scattering,nanoparticles,laser ablation,bubble dynamics
更新于2025-09-23 15:19:57
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Elliptic cavity filled with hybrid nanomaterial under consideration of magnetic field
摘要： CVFEM usage for modeling of nanomaterial flow style in a permeable elliptical tank including Lorentz effect was scrutinized in current research. Hybrid material with use of homogeneous model was applied and radiation term has been involved in governing equations. Outputs have been depicted in contours and plots. In addition, new formula for Nu was reported. Augment of Nu with considering greater permeability can be explained by stronger temperature gradient in cases with higher Da. Nanomaterial flow become suppress with augment of Ha which results lower Nu. As Ha augment from 0 to 20, 18% reduction has been reported in Nu. Permeability has favor influence on nanomaterial flow and the impact of Ha is opposite of permeability.
关键词： Numerical modeling,Radiation,Hybrid nanomaterial,Lorentz
更新于2025-09-23 15:19:57
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Active control of chiral optical near fields on a single metal nanorod
摘要： Chiral optical fields (typified by circularly polarized light) localized on the nanoscale enhance the chiral light-matter interaction, which may provide novel potential applications. This property enables the development of an ultrasensitive method for characterization of chiral molecules and nanoscale magnetic control realized by an all-optical method to interconnect spintronic nano-optical devices. A local chiral light source with switchable handedness or controllable chirality is indispensable for building such applications for practical use. In the current major method used for local chiral light generation, the handedness of the light is controlled by the handedness of the nanomaterial, which is not convenient when we need to change the handedness of the light. We experimentally achieve here generation and active control of a highly chiral local optical field by using a combination of an achiral gold nanorod and achiral linearly polarized optical field. By tilting the azimuth angle for the incident linear polarization relative to the axis of the nanorod, either left- or right-handed circularly polarized local optical fields can be generated. Our work may give us a chance to pioneer analytical applications of chiral optical fields and novel spintronic nano-optical devices.
关键词： near-field optics,chiral plasmonics,scanning near-field optical microscope,nanomaterial,polarimetry
更新于2025-09-19 17:15:36
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Efficient electrochemical detection and extraction of copper ions using ZnSe-CdSe/SiO2 core-shell nanomaterial
摘要： Development of nanostructured materials has received tremendous attention nowadays due to their unique properties and efficacious in wide range of applications. Herein, we present a facile synthesis of ZnSe-CdSe/SiO2 core-shell nanomaterial for pollutants monitoring and environmental remediation purposes. The utility of ZnSe-CdSe/SiO2 core-shell nanomaterial was explored toward electrochemical detection and adsorptive removal of copper ions from aquatic system. Experimental results reveal that both electrochemical detection and adsorption of Cu(II) using ZnSe-CdSe/SiO2 nanomaterial strongly depends on the solution pH, with an optimum pH of 5. Based on the results, the amperometric sensor based on ZnSe-CdSe/SiO2 core-shell nanomaterial modified electrode exhibited a detection limit of 50 μgL?1. Moreover, ZnSe-CdSe/SiO2 core-shell nanomaterial as adsorbent demonstrated high uptake capacity equals to 126.25 mgg?1. Thus, ZnSe-CdSe/SiO2 core-shell nanomaterial can be employed as promising material for several environmental remediation purposes.
关键词： Core-shell,Adsorption,Copper,ZnSe-CdSe/SiO2,Electrochemical Sensor,Nanomaterial,Extraction
更新于2025-09-19 17:15:36
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Influences of Mn doping on the microstructural, semiconducting and optoelectronic properties of HgO nanostructure films
摘要： Mn-doped HgO nanostructured thin films (Hg1-xMnxO) have been prepared using electron beam evaporation technique on Corning glass (1022) substrate at room temperature with different concentrations x = 0, 0.015, 0.05, 0.1, 0.15 and 0.2. The microstructural, morphological, semiconducting and optoelectronic properties of the films have been investigated. The X-ray diffraction spectra suggest a hexagonal wurtzite type structure with lattice parameters decreased with increasing Mn content. It was found that the average particle size of the films decreases with increasing Mn doping which is confirmed by FE-SEM and AFM micrographs. The optical band gap of the investigated Mn-doped HgO nanocrystalline films is determined from the absorption coefficient and found to increase with the increase of Mn concentration which is attributed to the sp-d exchange interaction and/or the quantum confinement effect. The refractive index and extinction coefficient of the Mn-doped HgO films are also reported. The refractive index dispersion n(λ) is analyzed by single-effective-oscillator dispersion model proposed by the Wemple–DiDomenico (WDD). The oscillator parameters were estimated. The obtained dispersion values are suitable for the design of optoelectronic devices.
关键词： microstructure properties,Nanomaterial,Diluted magnetic semiconductors,single oscillator parameters,optical properties
更新于2025-09-19 17:15:36
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High-performance solar vapor generation of Ni/carbon nanomaterials by controlled carbonization of waste polypropylene; ??ˉ??§?￠3????o????è???????ˉ????¤?é??/?￠3?o3?±3????????¨?o?é????????è???°?è????￠;
摘要： Solar vapor generation is emerging as a promising technology using solar energy for various applications including desalination and freshwater production. However, from the viewpoints of industrial and academic research, it remains challenging to prepare low-cost and high-efficiency photothermal materials. In this work, we report the controlled carbonization of polypropylene (PP) using NiO and poly(ionic liquid) (PIL) as combined catalysts to prepare a Ni/carbon nanomaterial (Ni/CNM). The morphology and textural property of Ni/CNM are modulated by adding a trace amount of PIL. Ni/CNM consists of cup-stacked carbon nanotubes (CS-CNTs) and pear-shaped metallic Ni nanoparticles. Due to the synergistic effect of Ni and CS-CNTs in solar absorption, Ni/CNM possesses an excellent property of photothermal conversion. Meanwhile, Ni/CNM with a high specific surface area and rich micro-/meso-/macropores constructs a three-dimensional (3D) porous network for efficient water supply and vapor channels. Thanks to high solar absorption, fast water transport, and low thermal conductivity, Ni/CNM exhibits a high water evaporation rate of 1.67 kg m?2 h?1, a solar-to-vapor conversion efficiency of 94.9%, and an excellent stability for 10 cycles. It also works well when converting dye-containing water, seawater, and oil/water emulsion into healthy drinkable water. The metallic ion removal efficiency of seawater is 99.99%, and the dye removal efficiency is >99.9%. More importantly, it prevails over the-state-of-art carbon-based photothermal materials in solar energy-driven vapor generation. This work not only proposes a new sustainable approach to convert waste polymers into advanced metal/carbon hybrids, but also contributes to the fields of solar energy utilization and seawater desalination.
关键词： synergistic effect,waste polymer,solar vapor generation,Ni/carbon nanomaterial,controlled carbonization,photothermal materials
更新于2025-09-19 17:13:59