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Effect of Different Inorganics on Polyimide-based Bragg Grating Humidity Sensor
摘要： Effect of activated carbon and lithium chloride on polyimide-based fiber Bragg Grating relative humidity sensor has been experimentally investigated. Through dip coating process, organic-inorganic hybrid coatings were deposited on fiber Bragg grating to form different relative humidity sensors. Experimental results show that the addition of activated carbon or lithium chloride alone could increase the humidity sensitivity (1.67 times and 1.61 times, respectively), but the structure which contains both lithium chloride and activated carbon increases the sensitivity most (3.9 times). In the 14-day stability test, the fluctuation of pure polyimide sensor is ± 6.5%, while the ones of activated carbon sensor, lithium chloride sensor, activated carbon and lithium chloride sensor are ± 3%, ± 8%, and ± 1.6%.
关键词： lithium chloride,fiber Bragg grating,activated carbon,polyimide,humidity sensor
更新于2025-09-23 15:22:29
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Photo-refreshable electrochemical sensor based on composite electrode of carbon nanotubes and TiO2 nanoparticles
摘要： Surface fouling and passivation on the electrode during electrochemical process is a major challenge for the practical applications of electrochemical sensors. Herein, a photo-refreshable electrochemical sensor was presented based on carbon nanotubes/TiO2 nanoparticles (CNTs/TiO2-NPs) composite electrode, which not only exhibits high electrochemical activity towards the determination of 5-hydroxytryptamine and dopamine, but also displays excellent reproducibility in the surface electrochemical monitoring without damaging microstructure. The linear range for 5-hydroxytryptamine determination is 0.5-400 μM (R=0.991) under UV light irradiation with a detection limit of 0.47 μM (S/N=3). The CNTs/TiO2-NPs electrode also shows excellent response to dopamine, with the linear range of 0.05 μM to 100 μM and a detection limit of 0.022 μM (S/N =3). The high performance of this photo-refreshable electrochemical sensor should be attributed to the excellent photocatalytic activity of the TiO2-NPs and the high electrochemical activity of CNTs.
关键词： carbon nanotubes,photocatalysis,TiO2 nanoparticles,electrochemical sensors,surface fouling
更新于2025-09-23 15:22:29
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Porosity Determination of Carbon and Glass Fibre Reinforced Polymers Using Phase-Contrast Imaging
摘要： This paper presents multi-modal image data of different fibre reinforced polymer samples acquired with a desktop Talbot-Lau grating interferometer (TLGI) X-ray computed tomography (XCT) system and compare the results with images acquired using conventional absorption-based XCT. Two different fibre reinforced polymer samples are investigated: (i) a carbon fibre reinforced polymer (CFRP) featuring a copper mesh embedded near the surface for lightning conduction and (ii) a short glass fibre reinforced polymer (GFRP) sample. The primary goal is the non-destructive detection of internal defects such as pores and the quantification of porosity. TLGI provides three imaging modalities including attenuation contrast (AC) due to absorption, differential phase contrast (DPC) due to refraction and dark-field contrast (DFC) due to scattering. In the case of the CFRP sample, DPC is less prone to metal streak artefacts improving the detection of pores that are located close to metal components. In addition, results of a metal artefact reduction (MAR) method, based on sinogram inpainting and an image fusion concept for AC, DPC and DPC, are presented. In the case of the GFRP sample, DPC between glass fibres and matrix is lower compared to AC while DPC shows an increased contrast between pores and its matrix. Porosity for the CFRP sample is determined by applying an appropriate global thresholding technique while an additional background removal is necessary for the GFRP sample.
关键词： Porosity,Carbon and glass fibre reinforced polymers,Talbot-Lau grating interferometer,X-ray computed tomography,Differential phase contrast
更新于2025-09-23 15:22:29
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Enhanced solar steam generation using carbon nanotube membrane distillation device with heat localization
摘要： High-efficiency solar steam generation through interfacial solar heating of the membrane is a promising approach to alleviate the shortage of freshwater resources. In this work, we developed a membrane distillation device (MDD), consisting of a carbon nanotube (CNT) membrane as solar absorption layer, a qualitative filter paper as water transmission pipeline and an aerogel blanket as thermal insulator to achieve efficient solar harvesting and heat localization for enhancing water evaporation. The results illustrated that the MDD achieved a thermal conversion efficiency of up to 84.6% at a light intensity of 1 kW m?2 and showed superior cyclic stability for 10 cycles test. As a consequence, the self-assembled and reusable MDD was suitable as a promising candidate for seawater desalination.
关键词： Heat localization,Solar steam generation,Solar harvesting,Carbon nanotube
更新于2025-09-23 15:22:29
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[IEEE 2018 International Semiconductor Conference (CAS) - Sinaia (2018.10.10-2018.10.12)] 2018 International Semiconductor Conference (CAS) - Metal-Insulator Transition in Monolayer M<inf>o</inf>S<inf>2</inf> for Tunable and Reconfigurable Devices
摘要： In this paper, we show the electromagnetic design of a small patch antenna based on a molybdenum disulphide (MoS2) monolayer, with an area of only 22mm2, that exhibits high radiation efficiency and large tunability in microwaves at 10GHz thanks to a metal-insulator transition (MIT) induced by electrostatic gating. Furthermore, the MIT in MoS2 is used to reconfigure a tunable carbon nanotube-based filter, conferring it different functionalities: low-pass, high-pass and band-pass around 2GHz, while its carbon nanotube varactors allow tuning the cutoff frequency or central frequency.
关键词： tunable filters,carbon nanotubes,Microstrip antennas,molybdenum compounds
更新于2025-09-23 15:22:29
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Composite materials based on active carbon/TiO2 for photocatalytic water purification
摘要： The present work describes the preparations of active carbon (AC) – titania composites with different AC/TiO2 ratio, their characterization using XRD, BET and SEM and evaluation of adsorption capacity and photocatalytic activity in aqueous solution using azo-dye Acid Orange 7 (AO7). Composite materials based on AC/TiO2 were prepared from commercial active carbon (1737 m2/g) and TiO2 (P25, 45 m2/g) materials by the mixing method. The studied parameters were the ratio of AC/TiO2, hydrothermal treatment and milling of as-prepared composites. The composites show increased BET surface area proportional to the content of AC in the material. The disappearance of AO7 is due to the combination two processes, e. g. adsorption and photocatalytic oxidation which takes place in parallel. Thus the overall removal of AO7 has been corrected on adsorption (measured in dark) to obtain the rate of AO7 disappearance due to photocatalytic oxidation (PO). The optimum ratio of AC/TiO2 was found to be 0.23 where PO rate is only slightly lower than that for P25 and overall AO7 removal is twice higher than for P25 itself. The less intensive (low-frequency) milling of the composite results in the decrease of carbon particle size, increase in AO7 adsorption and decline in the PO of AO7. More intensive milling (high-frequency) results in the decrease of the anatase content, appearance of the small amount of brookite and almost negligible PO rate of AO7. Irradiation of low-frequency milled AC/TiO2 composite in aqueous suspensions resulted in the generation of a comparable concentration of hydroxyl radical spin-adduct (?DMPO-OH) as non-milled composite, high-frequency milled composite revealed substantially lower ?DMPO-OH concentration which can be explained by the increased concentration of carbon-centered radicals in AC acting as scavengers of photogenerated electrons.
关键词： adsorption,Active carbon,P25,EPR spectroscopy,AO7,photocatalytic oxidation
更新于2025-09-23 15:22:29
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Effects of low-temperature sintering on surface morphology and electrical performance of silver nanoparticle/carbon nanotube composite films
摘要： Silver nanoparticle (AgNP)/carbon nanotube (CNT) composites are drawing increasing attention for several applications, especially where transparency is required. However, interfacial interaction and stability of the AgNP/CNT composites have been scarcely investigated. In the present study, transparent coatings were prepared from dispersed AgNP-coated multiwalled CNTs and exposed to different annealing conditions. The changes in surface morphology and evolution of interfacial configuration of AgNP-decorated CNT transparent composite films were investigated. Under certain conditions, CNT ropes were glued to one another by the melted AgNP aggregates, resulting in the improvement of the measured electrical properties. The in situ measurements of the electrical properties allowed correlating the AgNPs sintering mechanism with the morphological observations. Notably, at a given temperature, increasing the initial film density increased the time necessary to complete the AgNPs sintering. The obtained results show that the electrical resistance can be used as a tool to indirectly monitor the network state of transparent AgNP-decorated CNT composite films, hence paving the way to tuning the composite film properties with a high precision for the desired application. These findings also explain the mechanism of reinforcement of polymer nanocomposites by the current nanofillers.
关键词： A. Silver nanoparticle,B. Carbon nanotube,E. In situ monitoring,D. Sintering,F. Electrical properties,C. Nanocomposite
更新于2025-09-23 15:22:29
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Fabrication of new metal-free materials for the hydrogen evolution reaction on base of the acridine derivatives immobilized on carbon materials
摘要： The process of adsorption on carbon material (Vulcan XC-72 (VU)) of organic heterocyclic compounds: acridine (I) and its derivatives 9-phenylacridine (II) and N-methyl-9-phenylacridium iodide (III) was studied in detail. Quantitative data on physical adsorption were obtained for all compounds. Based on the adsorption isotherms of Langmuir, the adsorption equilibrium constants K, the parameter A∞ and ΔG0 ad were calculated. It has been shown that the adsorption of compounds I and II is a structurally dependent process that depends on the nature and size of the functional substituents in the molecule, and the adsorption of compound III has a complex mechanism and partially proceeds through the stabilization stage by the functional groups present on the surface (-COOH, -COH, -OH). With the use of quantum chemical calculations, it has been established that the process of adsorption of compounds on the surface of a carbon materials having sections with a graphite-like structure is thermodynamically unprofitable because of the high difference in the energies of the adsorbent's boundary orbitals and the substrate. Using the cyclic voltammetry method, the electrochemical properties of organic compounds immobilized on the surface of a carbon material were studied.
关键词： Electocatalysis,Acridine derivatives,Immobilization,Adsorption,Carbon materials,Hydrogen evolution reaction
更新于2025-09-23 15:22:29
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Reaction Packaging CoSe <sub/>2</sub> Nanoparticles in N-Doped Carbon Polyhedra with Bifunctionality for Overall Water Splitting
摘要： Water electrolysis is a promising approach for green and large-scale hydrogen production; however, there are still challenges for developing efficient and stable bi-functional electrocatalysts towards the hydrogen and oxygen evolution reactions. Herein, zeolitic imidazolate framework-67 (ZIF67) was used as the precursor for the construction of CoSe2 nanoparticles trapped in N-doped carbon polyhedra (NC). Among as-obtained CoSe2-NC hybrid, highly active CoSe2 nanoparticles in sizes of 10-20 nm are encapsulated in N-doped few-layer carbon shell, avoiding their easy aggregations of CoSe2 nanoparticles as well as enhancing the long-term stability. The unique nanostructured CoSe2-NC hybrid with a hierarchical porosity and 3D conductive framework thus fully exerts outstanding bi-functional catalytic activity of CoSe2 centers. As a result, the CoSe2-NC hybrid as bi-functional catalysts for overall water splitting delivers a high current density of 50 mA cm-2 with applied voltage of ~1.73 V in alkaline electrolyte, with a promising stability over 50000 s.
关键词： selenide reaction,ZIF67,bifunctional electrocatalyst,overall water splitting,carbon polyhedra
更新于2025-09-23 15:22:29
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Catalytic synthesis of SiC nanowires in an open system
摘要： SiC nanowires (NWs) are usually synthesized in a closed vacuum reaction system which limits the yield of SiC NWs. In this work, SiC NWs and carbon nanotubes were synthesized in an open tube furnace at 1550 ℃ with Si powder as silicon sources, ethanol as carbon sources and ferrocene as catalyst. The as-synthesized products were ultralong β-SiC NWs with the diameter about 80-100 nm and the length up to several tens micrometers. The diameter of the carbon nanotubes was about 20-30 nm. The carbon nanotube yarns about 20 cm in length were obtained at the end of the tube furnace. The growth mechanism of SiC NWs and carbon nanotubes were proposed. Compared with the traditional synthetic techniques in the high vacuum closed system, the novel synthesis method in the open system provided a new approach to the synthesis of SiC NWs.
关键词： Carbon nanotubes,SiC nanowires,Open reaction system,Growth mechanism
更新于2025-09-23 15:22:29