فهرست مطالب

  • Volume:10 Issue:3, 2019
  • تاریخ انتشار: 1398/04/10
  • تعداد عناوین: 10
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  • Mathi Vathani Arunananthan, Dhanalakshmi Selvaraj, Prithivikumaran Natarajan * Pages 230-241
    In this study, we report an effective uric acid (UA) electrochemical biosensor using Cu-TiO2 electrode. UA is a biomedical compound that plays a vital role in human metabolism. The abnormal level of UA leads to several diseases. TiO2 and Cu-TiO2 with various concentrations were deposited on glass substrates by spray pyrolysis technique. The structural study shows by X-ray diffraction analysis shows that all the films are in anatase phase with tetragonal structure and confirm the incorporation of Cu ions into TiO2 lattice. The morphology and chemical composition of TiO2 and Cu-TiO2 were characterized by scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS). These studies reveal that the aggregation of particles occurs due to doping and confirm the presence of Cu. The optical analysis was studied by UV-Vis absorption and photoluminescence spectroscopy, which indicates the band gap changes, shift in absorption peak and defects. Cyclic voltammetry (CV) was used to analyse the performance of the Cu-TiO2 as the electrochemical biosensor. Cu-TiO2 electrochemical biosensor exhibits good sensitivity, linearity and high stability for the detection of UA.
    Keywords: Cu- TiO2, Electrochemical studies, Sensing, Spray pyrolysis, Thin films, Uric acid
  • Gopal Suresh, Rajagemberam Sathishkumar, Baskaran Iruson *, Balaraman Sathyaseelan, Krishnmoorthy Senthilnathan, Elayaperumal Manikandan Pages 242-251
    In this paper, we report the synthesis of tin oxide (SnO2) nanoparticles by co-precipitation technique. The structural, surface morphology, thermal and optical properties of the SnO2 samples were analysed using X-ray diffraction (XRD), High-resolution transmission electron microscopy (HRTEM), Fourier transformed infrared (FTIR) spectrum, thermo gravimetric analysis (TGA/DTA), photoluminescence spectrum (PL) and UV–Vis spectroscopy techniques. X-ray diffraction patterns showed the SnO2 crystallites with the tetragonal rutile structure and UV-Vis analysis showed the characteristic absorbance peak at 345 nm. In the PL emission spectrum, three peaks were found at 500, 605 and 651nm, due to the oxygen vacancy defect. Finally, Hall coefficient was also estimated for various values of an applied magnetic field and bias current applied to the SnO2 sample. From the detailed study, it has been found that the prepared sample is an n-type semiconductor.
    Keywords: Hall Effect, Luminescence, nanoparticles, Semiconducting materials, Tin Oxide
  • Hilal Demir Kivrak *, Nahit Akta?, Aykut Caglar Pages 252-259
    Herein, graphene oxide is produced by electrochemical oxidation method from graphite rod to examine its hydrogen peroxide sensing ability. The electrochemically produced graphene oxide is characterized by SEM and XRD. A few layers of Graphene Oxide(GO) sheets and corrugations in graphene sheets appeared intensely crumpled and folded into a typical wrinkled structure after electrochemical oxidation. Electrochemical measurements are carried out cyclic voltammetry (CV) and chronoamperometry (CA) on graphene oxide and graphite. As a result, graphene oxide exhibits the highest performance toward electrochemical oxidation of H2O2 in 0.1 M phosphate buffered solution (PBS). In addition, CA is employed for the determination of H2O2 at the applied potential of 0.0 V (vs. Ag/AgCl). The electrochemical sensor exhibits fast and selective responses to H2O2 concentration.
    Keywords: Electrochemical, Graphene oxide, Graphite, Hydrogen peroxide, Nonezymatic sensor
  • Fatemeh Soleimani, Mahdi Salehi *, Ahmad Gholizadeh Pages 260-271
    In this study phase- pure new spinel structure, Mn0.5Cu0.5Cr2O4 was prepared by hydrothermal method successfully and the degradation of Malachite green as an organic pollutant was investigated and compared with CuCr2O4. Purification of obtained nanoparticles was measured by using X-ray diffraction method (XRD) in which crystal structure and the structural properties were studied by using X’Pert package and Fullprof program. Also, the morphology of obtained materials was modified by field-effect scanning electron microscopy (FESEM). These materials were characterized by Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA), respectively. UV-vis diffuse reflectance analysis was done for determination of band gape which evaluated 1.37eV.The photocatalytic application of synthesized materials was evaluated by the degradation of malachite green (MG) in the presence of H2O2 that were assessed by UV–vis spectroscopy analysis. The comparison study of photocatalytic result reviled that Mn0.5Cu0.5Cr2O4 has higheractivity than CuCr2O4.
    Keywords: CuCr2O4, Hydrothermal method, Malachite green, Mn0.5Cu0.5Cr2O4, Photocatalytic activity
  • Durgadevi Ganesan, Ajaikumar Samikannu, Chandran Muthaiah, Kuppusamy Muniyan Ramasamy, Dinakaran Kannaiyan * Pages 272-280
    An efficient photocatalyst consisting of CdS nanoparticle dispersed mesoporous silica-titania was prepared using amphiphilic triblock copolymer P123 as template and silica-titania sol–gel precursors. The CdS nanoparticle was incorporated into silica-titania mesoporous nanosturctures by post impregnation method. The synthesized catalyst has been characterized by FTIR, TEM, SEM, and EDAX analysis. The CdS nanoparticles incorporated silica-titania mesoporous particles exhibited an enhanced light harvesting, large surface area and excellent photocatalytic activity. Photocatalytic degradation experiments on methyleneblue solution at different pH of the medium revealed that, the catalyst ST0.5CdS0.2 is more effective in basic medium with a degradation efficiency of 98%. In addition, the catalyst is also tested for dye degradation against a raw textile dye effluent containing multiple dye molecules, and their results indicated that the raw effluent can be decolorized within 90min using ST0.5CdS0.2 catalyst.
    Keywords: Cadmium sulfide, Mesoporous material, Methylene blue, Photocatalyst, Photodegradation, Silica-titania, Textile effluent
  • Ali Rahnamaei, Gholamreza Zare Fatin *, Abdollah Eskandarian Pages 281-290
    A novel and robust scheme for radix-4 Booth scheme implemented in Carbon Nanotube Field-Effect Transistor (CNTFET) technology has been presented in this paper. The main advantage of the proposed scheme is its improved speed performance compared with previous designs. With the help of modifications applied to the encoder section using Pass Transistor Logic (PTL), the corresponding capacitances of middle stages have been reduced considerably. As a result, total transistor count along with power consumption has been decreased illustrating the other advantages of the designed structure. For evaluation of correct functionality, simulations using CNTFET 32nm standard process have been performed for the designed scheme which depict the latency of 195ps for critical path. Meanwhile, comparison with previous works using the Power Delay Product (PDP) criteria demonstrates the superiority of the proposed structure suggesting that our circuitry can be widely utilized for high speed parallel multiplier design.
    Keywords: CNTFET, High speed, Low Power, Parallel multiplier, Radix-4 Booth scheme
  • Arunkumar Lagashetty *, Amruta Pattar, Sangappa Ganiger Pages 291-296
    Nanomaterials are attracted a great deal of attention from scientific community due to its unique properties and applications. The small size ferrites have opened the door for intensive research to utilize their properties for biomedical applications. Cobalt ferrite nanomaterials and its silver doped (Ag-doped) nanocomposites have been prepared using solid state combustion method. This combustion method was carried out using polyvinyl alcohol (PVA) as a fuel for combustion reaction. The structure of the prepared cobalt ferrite and its silver nanocomposites were characterized by using X-ray diffraction (XRD) tool and morphology by Scanning Electron Micrograph (SEM) tool respectively. Bonding nature of the sample was studied by Fourier transfer infra-red (FT-IR) studies. Presence of the metals in the composites was confirmed by Energy dispersive X-Rays (EDX) pattern.
    Keywords: Ag doped, Cobalt ferrite, Energy dispersive X-Rays (EDX), Fourier transfer infra-red (FT-IR), Scanning Electron Micrograph (SEM), X-ray diffraction (XRD)
  • Kameliya Ghaffarzadeh, Pirouz Derakhshi, Mohammad Yousefi *, Ali Mahmoudi, Parviz Aberoomand Azar Pages 297-303
    In this research, first, nanoparticles of SrFe11.98Mg0.1Sn0.1O19 hexaferrite was synthesized via sol-gel auto-combustion process and then the nanocomposites of hexagonal ferrites/perovskite with the amounts of SrFe11.98Mg0.1Sn0.1O19/BaTiO3 (50/50, 40/60, 70/30 w/w) was prepared by the ball-milling method. Fourier transform infrared (FTIR) spectrums of SrFe11.98Mg0.1Sn0.1O19,was shown that the bands at about 400 and 500 cm-1 proved the formation of nano hexagonal ferrites. On the FTIR spectrum of nanocomposites, the Ti-O bond of perovskite appeared. X-ray diffraction (XRD) analysis was confirmed the formation of hexaferrite and perovskite phase of BaTiO3. Field emission electron microscopy (FESEM) pictures have represented the formation of hexagonal nanoparticles and sphere shape of BaTiO3. Vibrating sample magnetometer (VSM) hysteresis loop was revealed that SrFe11.98Mg0.1Sn0.1O19 belonged to the soft magnetic materials due to the 604.45Oe coercivity. By formation of nanocomposites, the coercivity was increased up to 1500 Oe. Vector network analyzer (VNA) analysis was revealed the maximum absorption of -16.4 db at 11.5 GHz frequency for SrFe11.98Mg0.1Sn0.1O19/BaTiO3 (60/40) nanocomposite sample.
    Keywords: Ball- milling, Coercivity, Hexaferrite, Perovskite, Vector network analyzer
  • Hadi Beitollai *, Sayed Zia Mohammadi, Somayeh Tajik Pages 304-312
    In the present work, a new sensor for morphine (MO) measurement, based on modification of screen-printed carbon electrode (SPE) by using magnetic core shell manganese ferrite nanoparticles was reported. The electrochemical behaviour of MO was investigated in phosphate buffer solution (pH 7.0) by voltammetry. The electrochemical response of the modified electrode toward morphine was studied by means of cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry (CHA). The modified electrode displayed a decrease in the overpotential (ca. 80 mV) and an obvious increase in the peak current was observed compared to the non-modified SPE. The results indicated that modified screen-printed electrode enhanced electrocatalytic activity towards the oxidation of MO. Under the optimized conditions the calibration curve for MO was linear from 0.1 – 600.0 μM and the detection limit based on 3Sb/m was 0.02 µM. The application of the proposed method in analysis of real sample was also evaluated and satisfactory results were obtained.
    Keywords: Magnetic core shell nanoparticles, Modified electrode, Morphine determination, Screen-printed carbon electrode, Voltammetry
  • Reza Shabannia * Pages 313-319
    Well-aligned Cu-doped ZnO nanorods were successfully synthesized on polyethylene terephthalate (PET) substrate using chemical bath deposition method. The structural and optical properties of Cu-doped ZnO nanorods were investigated using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX) and photoluminescence (PL) spectroscopy. A metal-semiconductor-metal (MSM) UV photodetector was successfully fabricated using high-quality Cu-doped ZnO nanorods. The dark current and photocurrent of the MSM photodetector based on Cu doped ZnO nanorods were 20.5  and 2.22 at bias voltage of 5 V, respectively.  Under bias voltage of 5 V, the responsivity of the UV photodetector was. The calculated photosensitivity of the UV photodetector was 107.4 at bias voltage of 5 V. The fast response time (191 ms) and recovery time (261 ms) of the fabricated UV photodetectors were achieved in UV turn-on/off switching measurements.
    Keywords: Chemical bath deposition, Crystal structure, Cu-doped ZnO nanorods, Polyethylene terephthalate, UV photodetector