Current Issue : January - March Volume : 2018 Issue Number : 1 Articles : 5 Articles
The main idea behind this work was demonstrated in a form of a new thermoelectrochromic sensor on a flexible substrate using\ngraphene as an electrically reconfigurable thermal medium (TEChrom). Our approach relies on electromodulation of thermal\nproperties of graphene on poly(ethylene terephthalate) (PET) via mechanical destruction of a graphene layer. Graphene applied\nin this work was obtained by chemical vapor deposition (CVD) technique on copper substrate and characterized by Raman and\nscanning tunneling spectroscopy. Electrical parameters of graphene were evaluated by the van der Pauw method on the transferred\ngraphene layers onto SiO2 substrates by electrochemical delamination method. Two configurations of architecture of sensors,\nwithout and with the thermochromic layer, were investigated, taking into account the increase of voltage from 0 to 50V and were\nobserved by thermographic camera to define heat energy. Current-voltage characteristics obtained for the sensor with damaged\ngraphene layer are linear, and the resistivity is independent from the current applied. The device investigated under 1000W/m2\nexhibited rise of resistivity along with increased temperature. Flexible thermoelectrochromic device with graphene presented here\ncan be widely used as a sensor for both the military and civil monitoring....
Microwave-assisted chemical bath deposition (MW-CBD) was used to deposit zinc oxide nanorods (ZnO-NRs) films by using\ndifferent microwave irradiation time.The films exhibit a good crystallinity having a hexagonal wurtzite phase formation. Although\nthe dominant preferred orientation was not observed for the ZnO-5 and ZnO-10, ZnO-8 showed (002) preferred orientation.The\nemission scanning electron microscope (FESEM) showed almost randomly oriented hexagonal nanorods on the surface. A slight\ndecrease in the length of the observed hexagonal nanorods due to the increase in the irradiation time was observed, changing from\n550 nm to 300 nm. The p-Si/n-ZnO-NRs heterojunction photodiodes were fabricated. The current-voltage characteristics of these\nphotodiodes were investigated under dark and different illumination intensity. An increase in the reverse current with increasing\nillumination intensity confirmed that the fabricated photodiodes exhibited a photoconducting behavior. In addition, the barrier\nheight and series resistance values of the photodiodes were determined from capacitance-voltage measurements....
The present study describes a novel strategy for preparing thin Silicon 2D and 3D electrodes for\nlithium ion batteries by a spin coating method. A homogeneous and stable suspension of Si nanoparticles\n(SiNPs) was prepared by dispersing the nanoparticles in 1-methyl-2-pyrrolidone (NMP) or in the room\ntemperature ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (Pyr14TFSI).\nThis proposed methodology was successfully employed to prepare 2D and 3D with different aspect ratios\nelectrodes. Both 2D and 3D materials were then used as anode materials. The 2D SiNPs anodes exhibit\na high reversible capacity, which is close to 3500 mAhÃ?·gâË?â??1 at C/10. For a higher discharge rate, the\ncapacity of the 2D anode is considerably improved by dispersing the nanoparticles in Pyr14TFSI instead\nof NMP solvent. In order to further improve the anode performances, graphene particles were added\nto the SiNPs suspension. The anodes prepared using this suspension method exhibit relatively low\ncolumbic efficiency during the first few cycles (less than 30%) and low reversible capacity (2800 mAhÃ?·gâË?â??1\nat C/10). The 3D SiNPs (NMP) electrode shows a higher intensity during cyclic voltammograms and a\nbetter stability under galvanostatic cycling than the 2D SiNPs (NMP) electrode....
The impacts of multiple slips with viscous dissipation on the boundary layer flow and heat transfer of a non-Newtonian nanofluid\nover a stretching surface have been investigated numerically. The Casson fluid model is applied to characterize the non-Newtonian\nfluid behavior. Physical mechanisms responsible for Brownian motion and thermophoresis with chemical reaction are accounted\nfor in the model. The governing nonlinear boundary layer equations through appropriate transformations are reduced into a set of\nnonlinear ordinary differential equations, which are solved numerically using a shooting method with fourth-order Runge-Kutta\nintegration scheme. Comparisons of the numerical method with the existing results in the literature are made and an excellent\nagreement is obtained. The heat transfer rate is enhanced with generative chemical reaction and concentration slip parameter,\nwhereas the reverse trend is observed with destructive chemical reaction and thermal slip parameter. It is also noticed that the\nmass transfer rate is boosted with destructive chemical reaction and thermal slip parameter. Further, the opposite influence is\nfound with generative chemical reaction and concentration slip parameter....
The effect of activation temperature on the structural properties and the electrochemical performance of KOH-activated carbon\nxerogel was investigated in range of 700 to 1000âË?Ë?C. At a high temperature (1000âË?Ë?C), the chemical activation regenerated a more\ncrystalline network structure of activated carbon xerogels, which was observed by Raman, XRD, and TEM images. Additionally,\nSEM images, BET, BJH, and ...
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