Current Issue : January - March Volume : 2015 Issue Number : 1 Articles : 7 Articles
Solid supported 2D assembly of silver nano cubes was fabricated by Langmuir-Blodgett technique and employed to investigate its\nsurface enhanced Raman scattering (SERS) and surface enhance fluorescence (SEF) activities by detecting Rh6G in solution of\nvaried concentrations, that is, 10?12 M, 10?9 M, 10?6 M, and 10?3 M. SERS was detected from a nanomolar concentration of Rh6G\nwhereas SEF was detected from a picomolar concentration. Further, the substrate was subjected to thermal annealing to fabricate\nplasmonic thin film. The formation of thin film was followed by monitoring its surface plasmon resonance spectra and atomic force\nmicroscopic images. It was observed that the characteristic spectral peaks of silver nanocubes merged into a broad spectral band\nas the annealing time was increased and the intensity of the band decreased with the formation of thin film. The obtained result\nimplies that thermal annealing could be a simple approach to create nanoscale gaps in SERS substrate and to engineer continuous\nthin film from the assembly of discrete nano particles....
The results of carbon-doped zinc oxide nanoparticles synthesized by CO2 microwave plasma at atmospheric pressure are presented.\nThe 2.45-GHz microwave plasma torch and feeder for injecting Zn granules are used in the synthesis of zinc oxide nanoparticles. The\nZn granules (13.5 g/min) were introduced into the microwave plasma by CO2 (5 l/min) swirl gas. The microwave power delivered\nto the CO2 microwave plasma was 1 kW. The synthesis of carbon-doped zinc oxide nanoparticles was carried out in accordance\nwith CO2 + Zn ? carbon-doped ZnO + CO. The synthesized carbon-doped zinc oxide nanoparticles have a high purity hexagonal\nphase. The absorption edge of carbon-doped zinc oxide nanoparticles exhibited a red shift from a high-energy wavelength to lower\nin the UV-visible spectrum, due to band gap narrowing. A UV-NIR spectrometer, X-ray diffraction, emission scanning electronmicroscopy,\nenergy dispersive X-ray microanalysis, Fourier transform infrared spectroscopy, and a UV-Vis-NIR spectrophotometer\nwere used for the characterization of the as-produced products....
Electrospraying (electrohydrodynamic spraying) is a method of liquid atomization by electrical forces. Spraying solutions or\nsuspensions allow production of fine particles, down to nanometer size. These particles are interesting for a wide variety of\napplications, thanks to their unprecedented chemical and physical behaviour in comparison to their bulk form. Knowledge of the\nparticle size in powders is important in many studies employing nanoparticles. In this paper, the effect of some process parameters\non the size of electrosprayed polyacrylonitrile particles is presented in the form of response surface model.The model is achieved\nby employing a factorial design to evaluate the influence of parameters on the polyacrylonitrile nanoparticle size and response\nsurface methodology. Four electrospraying parameters, namely, applied voltage, electrospraying solution concentration, flow rate,\nand syringe needle diameter were considered....
Iron oxide nanoparticles (Fe3O4-NPs) were synthesized using chemical coprecipitation method. Fe3O4-NPs are located in\ninterlamellar space and external surfaces of montmorillonite(MMT)as a solid supported at room temperature.The size of magnetite\nnanoparticles could be controlled by varying the amount of NaOH as reducing agent in the medium. The interlamellar space\nchanged from 1.24 nm to 2.85 nm and average diameter of Fe3O4 nanoparticles was from 12.88nm to 8.24 nm. The synthesized\nnanoparticles were characterized using some instruments such as transmission electron microscopy, powder X-ray diffraction,\nenergy dispersive X-ray spectroscopy, field emission scanning electron microscopy, vibrating sample magnetometer, and Fourier\ntransform infrared spectroscopy....
Perfluoropolyethers (PFPEs) are widely used as hard disk lubricants for protecting carbon overcoat reducing friction between the\nhard disk interface and the head during themovement of head during reading and writing data in the hard disk.Due to temperature\nrise of PFPE Zdol lubricant molecules on a DLC surface, how polar end groups are detached from lubricant molecules during\ncoating is described considering the effect of temperatures on the bond/break density of PFPE Zdol using the coarse-grained bead\nspring model based on finitely extensible nonlinear elastic potential. As PFPE Z contains no polar end groups, effects of temperature\non the bond/break density (number of broken bonds/total number of bonds) are not so significant like PFPE Zdol. Effects of\ntemperature on the bond/break density of PFPE Z on DLC surface are also discussed with the help of graphical results. How\nbond/break phenomenonaffects the end bead density of PFPE Z and PFPE Zdol on DLC surface is discussed elaborately. How the\noverall bond length of PFPE Zdol increases with the increase of temperature which is responsible for its decomposition is discussed\nwith the help of graphical results. At HAMR condition, as PFPE Z and PFPE Zdol are not suitable lubricant on a hard disk surface,\nit needs more investigations to obtain suitable lubricant.We study the effect of breaking of bonds of nonfunctional lubricant PFPE\nZ, functional lubricants such as PFPE Zdol and PFPE Ztetrao, and multidented functional lubricants such as ARJ-DS, ARJ-DD, and\nOHJ-DS on a DLC substrate with the increase of temperature when heating of all of the lubricants on a DLC substrate is carried\nout isothermally using the coarse-grained bead spring model by molecular dynamics simulations and suitable lubricant is selected\nwhich is suitable on a DLC substrate at high temperature....
Carbon nanotubes (CNTs) have been widely utilized as a novel drug carrier with promising future applications in biomedical\ntherapies due to their distinct characteristics. In the present work, carboxylic acid-functionalized single-walled carbon nanotubes\n(f-SWCNTs) were used as the starting material to react with anticancer drug, BA to produce f-SWCNTs-BA conjugate via ????-????\nstacking interaction. The conjugate was extensively characterized for drug loading capacity, physicochemical properties, surface\nmorphology, drug releasing characteristics, and cytotoxicity evaluation. The results indicated that the drug loading capacity was\ndetermined to be around 20 wt% and this value has been verified by thermogravimetric analysis.Thebinding of BA onto the surface\nof f-SWCNTs was confirmed by FTIR and Raman spectroscopies. Powder XRD analysis showed that the structure of the conjugate\nwas unaffected by the loading of BA.Thedeveloped conjugate was found to release the drug in a controlled manner with a prolonged\nrelease property. According to the preliminary in vitro cytotoxicity studies, the conjugate was not toxic in a standard fibroblast cell\nline, and anticancer activity was significantly higher in A549 than HepG2 cell line. This study suggests that f-SWCNTs could be\ndeveloped as an efficient drug carrier to conjugate drugs for pharmaceutical applications in cancer chemotherapies....
In this work, we study the synthesis of monodispersed Fe nanoparticles (Fe-NPs) in situ functionalized with oleic acid. The\nnanoparticles were self-assembled by inert gas condensation (IGC) technique by using magnetron-sputtering process. Structural\ncharacterization of Fe-NPs was performed by transmission electron microscopy (TEM). Particle size control was carried out\nthrough the following parameters: (i) condensation zone length, (ii) magnetron power, and (iii) gas flow (Ar and He). Typically\nthe nanoparticles generated by IGC showed diameters which ranged from ?0.7 to 20 nm. Mass spectroscopy of Fe-NPs in the\ndeposition system allowed the study of in situ nanoparticle formation, through a quadrupole mass filter (QMF) that one can use\ntogether with a mass filter.When the deposition system works without quadrupole mass filter, the particle diameter distribution is\naround +/?20%.When the quadrupole is in line, then the distribution can be reduced to around +/?2%....
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