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Light and flexible composite nanofibrous membranes for high-efficiency electromagnetic absorption in a broad frequency
摘要： With the fast advancement of up-to-date communication technologies, electromagnetic wave (EMW) absorption materials are widely required for various applications. However, it is still a big challenge to produce lightweight, flexible and high efficiency EMW absorption materials in a broad-ranging frequency. Herein, we designed to fabricate the magnetic and dielectric nanofibrous membranes which can be effectively used as EMW absorption materials by facile electrospinning process. The as-fabricated composite carbon nanofibers (CNFs), which combined the components of nickel, cobalt antioxidant nanoparticles and carbon nanotubes, exhibited outstanding magnetic, dielectric properties and strong absorption ability in a wide frequency range. These nanoparticles encapsulated in CNFs are extremely beneficial to the electrical conductivity of the composites through decreasing the contact loss within the CNFs by formation the metal-metal interfaces. Correspondingly, the RL value of -46.60 dB was reached at 4.88 GHz frequency range with a layer thickness of 5.5 mm for these mechanically light and flexible membranes. The enhanced absorption performance (<?10 dB) in the wide frequency band (4.16-18 GHz) can be achieved by selecting a suitable thickness of the material. Results demonstrate that the permittivity and permeability of developed samples have been largely improved due to the integrated interaction of all introduced components in the structure. The composite membranes are a promising candidate for scalable, lightweight and high performance EMW absorption materials in the frequency range from C band to Ku band (4?18 GHz).
关键词： Magnetic and dielectric properties,permeability,permittivity,carbon nanotubes,electromagnetic wave absorption
更新于2025-09-10 09:29:36
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Synthesis Optimization and Characterization of Visible-light Responsive Ce-doped Titanate Nanotubes for Enhanced Degradation of Polluting Dyes in Aqueous Environment
摘要： For the decomposition organic substrates in the reaction container, we developed Ce-doped titanate nanotubes as visible light responsive photo catalyst. Anatase titania and titanate nanotubes were prepared using the sol-gel method and hydrothermal method. The photoactivity of Ce-doped titanate nanotubes under visible light were dramatically improved than anatase titania and titanate nanotubes. All titania and titanate nanotubes were characterized using X-ray diffraction, field emission scanning electron microscopy, inductively coupled plasma-atomic emission spectroscopy and UV-Vis absorption spectroscopy. Their’s photocatalytic activities were investigated by the degradation rate of methylene blue solution under UV and visible light condition. The crystalinity of the titanate nanotubes were increased by Ce-doping compared with that of pure titania nanotube. In addition, the UV-Vis absorption ranges of Ce-doped anatase titania and Ce-doped titania nanotube were red shifted by Ce-doping. These morphology changes to nanotubes with Ce-doping will be very useful for practical application for decomposing color dyes included amino group in the wasted water.
关键词： visible light photoactivity,titanate nanotubes,Ce doping,photocatalyst,TiO2
更新于2025-09-10 09:29:36
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Facile Synthesis of Carbon Nanotubes Covalently Modified with ZnO Nanorods for Enhanced Photodecomposition of Dyes
摘要： Utilizing a one-pot solvothermal procedure novel one-dimensional zinc oxide-carbon nanotube nanohybrids (ZnCT) were synthesized in alcohol-alkali solution, free of catalytic assistance. The ZnCT hybrids were prepared through covalent modification of zinc oxide nanorods (ZnO NRs) with functionalized carbon nanotubes (f-CNTs). The morphology and microstructure of as-prepared ZnCT hybrids were characterized by scanning electron microscopy (SEM), powder X-ray diffraction, Raman, X-ray photoelectron and UV-vis absorption spectroscopies. SEM images of the ZnCT hybrids indicated that the ZnOethanol NRs grew longer along the vertical radial (0001) surface and aggregated to a lesser extent than the analogous ZnOmethanol NRs. Photodegradation analysis showed that the off-white ZnCTethanol hybrid with ascendant UV-visible light absorption had displayed superior photocatalytic activity towards Rhodamine B (RhB) dyes than either pure ZnOethanol, ZnOmethanol NRs or ZnCTmethanol hybrid, among which the photocatalytic activity of ZnOethanol NRs was better than that of ZnOmethanol NRs. Raman and X-ray photoelectron spectroscopy analyses confirmed a strong interaction between f-CNTs and ZnOethanol NRs in ZnCTethanol hybrid, in which Zn ions were chemically bonded to negatively charged oxygen-containing groups at the graphene-like surface of f-CNTs. The enhanced separation lifetime of the photogenerated electron-hole observed by surface photovoltage and photocurrent measurements of the ZnCTethanol hybrid was attributed to the efficient covalent linking of Zn-O-C and close contact configuration between the f-CNTs and ZnOethanol NRs. Further controlled photodegradation and electron spin resonance (ESR) analyses revealed that the photodegradation of RhB dyes resulted from photogenerated holes, and radical species, such as ?O2?、?OH?, which were formed in-situ. Details of the photocatalytic mechanism were also explored herein.
关键词： Solvothermal synthesis,ZnO nanorods,Carbon nanotubes,Dyes,Photodegradation
更新于2025-09-10 09:29:36
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Preparation and characterization of poly (3-hexylthiophene) / carbon nanotubes hybrid material via in-situ click chemistry
摘要： The poly(3-hexylthiophene) - multiwalled carbon nanotube hybrid material (P3HT-MWCNT) was successfully prepared in the Cu(I) / DBU catalyst system via in-situ click reaction. The properties of P3HT-MWCNT were measured by FTIR, 1H-NMR, UV-vis, XRD, TEM, SEM and AFM. The fluorescence spectrum of P3HT-MWCNT proved the covalent bond between P3HT and MWCNT, and P3HT could be coated on the surface of MWCNT. Compared with the physical blends of P3HT and MWCNT, P3HT-MWCNT prepared by click chemistry exhibited better thermal stability and a higher melting point of 243.2 oC. TG results also indicated that P3HT content of P3HT-MWCNT was 21.4%. It was expected to prepare novel organic-inorganic donor-acceptor hybrid material with good solubility, optical and thermal stability, which may be a promising material applied in preparation of organic photoelectron in the future.
关键词： multiwalled carbon nanotubes,chemical modification,poly(3-hexylthiophene),organic-inorganic hybrid material,Click chemistry
更新于2025-09-10 09:29:36
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Improvement of the third order nonlinear optical properties of nematic liquid crystal under the influence of different compositional percentage of doped SWCNT and the external electric field
摘要： In this research, the nematic liquid crystal (NLC) was doped with varying concentration (0-1 % wt.) of single walled carbon nanotubes (SWCNTs) at room temperature to study the nonlinear optical (NLO) properties of E5CN7@CNT cell.The third order NLO properties such as the nonlinear susceptibility, the nonlinear refraction (NLR) and the nonlinear absorption (NLA) were determined by using Z-scan techniques. The nonlinear studies have been done using a continuous wave (CW) He: Ne laser at 632.8 nm.Doping SWCNTs to eutectic uniaxial NLC (E5CN7) enhanced the third order nonlinear susceptibility, ??(3) and consequently the nonlinearity properties of composite systems improved.It is found that at lower concentration of CNTs (c< 0.75 % wt.), the third order nonlinear susceptibility are increased, but for concentration 0. 5<c<1 % wt., the third order nonlinear susceptibility are decreased. The negative sign of the observed NLR index, indicates that the E5CN7@CNT exhibits self-defocusing type optical nonlinearity. The two photon absorption (TPA) behavior, corresponding to negative sign NLA of samples. The reorientation of samples molecules amplifies upon the application of electric field, then nonlinearity increases.
关键词： Composite materials,Nematic liquid crystal,Carbon nanotubes,Third order nonlinear susceptibility,Nonlinear optics,Electric field,Z-scan method
更新于2025-09-10 09:29:36
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Simulation and experiment of field emission based on carbon nanotubes
摘要： In view of the bearing current of motor, a method of suppressing the bearing current using the ?eld emission characteristics of carbon nanotubes is proposed. Firstly, the advantages of carbon nano-materials and their ?eld emission properties are introduced. Secondly, the in?uence of the distance between the emitter tips and the anode metal plate on the electric ?eld intensity is analyzed by software simulation. Finally, ?eld emission experiments of TNF300 type carbon nanotube ?bers under non vacuum conditions were carried out by means of probes, microscopes and other experimental equipment. After obtaining the voltage and current of carbon nano-materials at di?erent distances, the volt-ampere characteristic curves and the ?eld emission characteristic curve were drawn, and the experimental results from di?erent distances were compared and analyzed.
关键词： carbon nanotubes,bearing current suppression,simulation and experiment,Field emission
更新于2025-09-10 09:29:36
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Light-Tuned DC Conductance of Anatase TiO2 Nanotubular Arrays: Features of Long-Range Charge Transport
摘要： Experimental results related to the photoactivated dc conductance of anatase TiO2 nanotubular arrays (aTNTAs) under pulsed irradiation by a laser light inside and outside the fundamental absorption band are presented. It is found that the mobility and diffusion coefficients of charge carriers in the examined aTNTA are extremely low due to a strong charge-phonon coupling, abundance of shallow traps, and hopping conductivity between adjacent nanotubes. We consider that the confining electric field appeared within the array structure due to the difference in the local concentrations of excess electrons and holes at large values of the dc conductance suppresses the drift current. In this case, the dc conductance of such aTNTAs is mainly matured by the diffusion of mobile carriers. A recurrent kinetic model for evolution of the dc conductance of aTNTAs under laser irradiation has been proposed to interpret the experimental results.
关键词： anatase nanotubes,laser irradiation,dc conductance,Urbach energy,drift current,inter-band transition,diffusion current,charge mobility
更新于2025-09-10 09:29:36
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Interfacial nanocomposite sensors (sQRS) for the core monitoring of polymer composites’ fatigue and damage analysis
摘要： The quick development of the smart factory and prognostic and health management (PHM), in the fields of aeronautic, automotive and green energies, is evidencing a need for sensors able to monitor the behavior of composite materials all along their life at the closest of the matter. In situ fabricated conductive polymer nanocomposite (CPC) sensors are bringing an interesting solution to this prospect as they can be integrated homogeneously in the core of composites to probe their deformations and damage. In particular fatigue which is one important mode of failure of polymer composites can be monitored from early signs of damage until the final breakage by analyzing the piezo-resistive response of quantum resistive strain sensors (sQRS) made of carbon nanotubes. We have developed all these aspects in the paper taking the example of a classical glass fibers/epoxy composite instrumented in its core with two sQRS to monitor its short and long term fatigue behavior.
关键词： damage detection,fatigue,structural health monitoring,Piezo-resistive strain sensors,conductive polymer nanocomposites,carbon nanotubes,polymer composites
更新于2025-09-10 09:29:36
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A facile method toward potentially next-generation bacteria detectors using polymer/MWCNT/Au nanocomposite films: A possibility to detecting ability through the shift in resonance frequency
摘要： The global market demands for new disposable wireless sensors for food, clinical, tissue, and drug industries in the near future. Gelatin-based multi-layer films were successfully prepared using a room temperature solution casting method. Anticipating future developments, we have looked at the potential applications of cost-effective passive RFID tags in the detection of bacteria (here trypsin was used for biosensing tests) in body fluids, foods, medicines, and much more. This paper is concerned with the measurement of the dielectric constant of materials remotely by using the frequency shift of RFID tags, in the first step. In continue, we establish a setup along with a novel multi-layer structure of gelatin films determining whether there exists any bacterium in a biological fluid or not, by using a physical approach. For this, penetration of bacterium through gelatin multi-layer films causes the RFID tags to be exposed to the biological fluid changing the dielectric constant, detected as a frequency shift. Samples were characterized utilizing FTIR, XRD, TGA, FESEM, tensile, and VNA analyzes. Our proposed wireless biomimetic sensor is able to detect trypsin within a few minutes. The immediate application of our designed biosensor is for the elderly and infants diapers, but further applications in biomedicine, biomedical engineering, food industry, and things like that can be anticipated.
关键词： Gelatin,Vector Network Analyzer,Au Nanoparticles,Trypsin,Carbon nanotubes
更新于2025-09-10 09:29:36
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European Microscopy Congress 2016: Proceedings || High resolution EELS on individual carbon nanotubes by monochromated TEM
摘要： Single-walled carbon nanotube (SWNT) has been known to exhibit a wide range of electronic properties upon its atomic arrangement [1,2]. However it is still difficult to directly correlate the distinct electronic properties with its atomic structure from an individual carbon nanotube. Here, we successfully demonstrate highly localized electronic properties of individual carbon nanotubes with precise atomic structures by means of transmission electron microscopy (TEM) consisting of a monochromator.
关键词： low-voltage,quantum object,Monochromator,carbon nanotubes,EELS
更新于2025-09-10 09:29:36