Current Issue : April - June Volume : 2015 Issue Number : 2 Articles : 8 Articles
Porous conductors with large surface-volume ratios have been applied to a variety of fields, including absorbents, flexible heaters,\nand electrodes for super capacitors. In this study, we implemented sensitive pressure sensors using the mechanical and electrical\ncharacteristics of conductive porous structures manufactured by immersing sponges into a carbon nano tube solution and then\nmeasured the change in resistance. When pressure was applied to conductive sponges, carbon nano tubes were attached to each\nother and the resistance was reduced by up to 20%. The carbon nano tube sponges, which were soft and had superior elasticity,\nwere quickly stabilized without any changes taking place in their shape, and they showed consistent change in resistance during\nexperiments of repetitive pressure. The pressure devices based on conductive porous sponges were connected to single-walled\ncarbon nano tube field effect transistors (SWCNT-FETs) and changes in their characteristics were investigated according to external\npressure....
Carbon nanotubes were synthesized via carbon suboxide disproportionation using iron as a catalyst at a low temperature of 160°C. In this procedure carbon suboxide used as a carbon source, through disproportionation free carbon clusters are formed, after the hydrothermal treatment the free carbon clusters developed as a nanotubes using iron catalyst. The reaction is as follows diethyl malonate dehydrates to produce carbon suboxide in the presence of phosphorous pentoxide and carbon suboxide disproportionate to carbon and carbon dioxide. The obtained product was characterized using FE-SEM, XRD, FTIR and Raman spectroscopy....
Magnetically recyclable materials should be ideal support in photo catalytic system because they permit the photo catalysts to be\nrecovered rapidly and efficiently by applying an external magnetic field such as,MnF2. In this paper,MnF2 and SiO2 layers constitute\na one-dimensional quasiperiodic photonic crystal according to Fibonacci. When the electromagnetic wave irradiates obliquely,\nthe transmission peak moves to higher frequency direction with the angle increasing. Both the number of transmission peaks\nand the transmission peaks of double-forked structure increase with the increase of structural progression. We also found that\nthe polarization of electromagnetic waves has influence on the transmission properties; TM wave transmission peak half wide is\nsignificantly greater than TE wave transmission peak half wide. The band gap near anti ferromagnetic (AF) resonance frequency\nbecomes narrow as the intensity of the applied static magnetic field increases. The as-prepared photonic crystal has tremendous\npotential practical use to eliminate organic pollutants from waste water....
Investigations and use of nano particles (NPs) as photo thermal (PT) agents in laser and optical nanotechnology are fast growing\nareas of research and applications. The potential benefits of NPs applications include possibility for thermal imaging and treatment\nof materials containing of NPs, applications of NPs for light-to-thermal energy conversion, in catalysis, laser nano medicine,\nand chemistry. Efficiency of applications of metallic NPs for laser and optical nanotechnology depends on plasmonic and\nthermophysical properties ofNPs, characteristics of radiation, and surrounding medium.Herewe present the results of comparative\nanalysis of NP properties (plasmonic, thermooptical, and others) allowing selecting their parameters for thermoplasmonic and\nphotonic applications. Plasmonic and thermooptical properties of several metallic (aurum, silver, platinum, cobalt, zinc, nickel,\ntitanium, cuprum, aluminum, molybdenum, vanadium, and palladium) NPs are theoretically investigated and analysis of them is\ncarried out. Investigation of the influence of NPs parameters (type of metal, radii, optical indexes, density, and heat capacity of NP\nmaterial), characteristics of radiation (wavelength and pulse duration), and ambient parameters on plasmonic and thermophysical\nproperties of NPs has been carried out. It was established that maximum value of thermooptical parameter (maximum NP\ntemperature) can be achieved with the use of absorption efficiency factor of NP smaller than its maximum value....
Gallium nanoparticles (Ga NPs) are currently the subject of vigorous research as possible substrates in surface-enhanced Raman\nscattering (SERS) experiments in the ultraviolet spectral domain. Verification of any comprehensive model of the interaction of\nelectromagnetic radiation with Ga NPs requires that complete polarimetric measurements be made. These spectropolarimetric\nproperties can be obtained using a Mueller matrix spectropolarimeter (MMSP). The position of localized surface plasmon\nresonances (LSPRs) and spectral depolarization data of Ga NPs in the 300 to 1100 nm spectral region are presented. Spectral\ndepolarization data may be of value in creating a better understanding of how light couples to individual nanoparticles, as well\nas the role played by in terparticle coupling and the connection to phenomena such as SERS....
Platinum (Pt) nanoparticles have been synthesized from a precursor solution of potassium tetrachloroplatinate (K2PtCl4) using\na matrix of bacterial cellulose (BC). The formation of Pt nanoparticles occurs at the surface and the inside of the BC membrane\nby reducing the precursor solution with a hydrogen gas reductant.The Pt nanoparticles obtained from the variations of precursor\nconcentration, between 3mMand 30 mM, and the formation of Pt nanoparticles have been studied using X-ray diffraction (XRD),\nscanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), and thermogravimetry analysis (TGA). Based on\nX-ray diffraction patterns, Pt particles have sizes between 6.3nm and 9.3 nm, and the Pt particle size increases with an increase in\nprecursor concentration. The morphology of the Pt nanoparticles was observed by SEM-EDS and the content of Pt particles inside\nthe membrane is higher than that on the surface of BC membranes. This analysis corresponds to the TGA analysis, but the TGA\nanalysis is more representative in how it describes the content of Pt particles in the BC membrane....
High-dose ther moluminescence dosimetry properties of novel zinc oxide nano phosphors synthesized by a solution combustion\nmethod in a glycine-nitrate process are presented for the very first time in this work. Sintered particles with sizes ranging between\n?500 nmand ?2 ????mwere obtained by annealing the synthesized ZnO at 900?C during 2 h in air. X-ray diffraction patterns indicate\nthe presence of the ZnO hexagonal phase, without any remaining nitrate peaks observed. The rmoluminescence glow curves of\nZnO obtained after being exposed to beta radiation consists of two maxima: one located at ?149?C and another at ?308?C, the latter\nbeing the dosimetric component of the curve. The integrated TL fading displays an asymptotic behavior for times longer than 16 h\nbetween irradiation and the corresponding TL readout, as well as a linear behaviour of the dose response without saturation in the\nstudied dose interval (from12.5 up to 400Gy). Such features place synthesized ZnOas a promising material for high-dose radiation\ndosimetry applications....
The dispersion state of in dividual MWCNT in the polymer matrix influences the mechanical, thermal, and electrical properties of\nthe resulting composite. One method of obtaining a good dispersion state of MWCNT in a polymer matrix is to functionalize the\nsurface of MWCNT using various treatments to enhance the surface energy and increase the dispersibility ofMWCNT. In this study,\nwett ability and surface energy of UV/O3 and acid-treated multi wall carbon nano tubes(MWCNTs) and its poly methyl me tha cry late\n(PMMA) polymer nano composites were measured using contact angle analysis in various solvent media. Contact angle analysis\nwas based on ethylene glycol-water-glycerol probe liquid set and data was further fitted into geometric mean (Fowkes), van Oss-\nChaudhury-Good (GvOC), and Chang-Qing-Chen (CQC) models to determine both non polar and acid base surface energy\ncomponents. Analysis was conducted on MWCNT thin films subjected to different levels of UV/O3 and acid treatments as well as\ntheir resulting MWCNT/PMMA nano composites. Contact angle analysis of thin films and nano composites revealed that the total\nsurface energy of all samples was well fitted with each other. In addition, CQC model was able to determine the surface nature and\npolarity of MWCNT and its nano composites. Results indicated that the wett ability changes in the thin film and its nano composites\nare due to the change in surface chemistry. Finally, electrical properties of nano composites were measured to investigate the effect\nof surface functionality (acid or basic) on the MWCNT surfaces....
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