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Chenari H.M.,Urmia University | Chenari H.M.,Maraghe University | Sedghi H.,Urmia University | Talebian M.,Urmia University | And 2 more authors.
Journal of Nanomaterials | Year: 2011

It is well known that metal/Tin-dioxide/metal sandwich structures exhibit a field-assisted lowering of the potential barrier between donor-like center and the conduction band edge, known as the Poole-Frenkel effect. This behavior is indicated by a linear dependence of Iog J on V1/2, where J is the current density, and V is the applied voltage. In this study, the electrical properties of Cu/nano-SnO2/Cu sandwich structures were investigated through current-voltage measurements at room temperature. Also, an attempt to explore the governing current flow mechanism was tried. Our results indicate that noticeable feature appearing clearly in the current-voltage characterization is the Poole-Frenkel and space-charge-limited conduction mechanisms. © 2011 Hossein Mahmoudi Chenari et al. Source

Gholivand M.B.,Razi University | Abolghasemi M.M.,Razi University | Abolghasemi M.M.,Maraghe University | Piryaei M.,Razi University | And 2 more authors.
Food Chemistry | Year: 2013

To avoid the traditional and time consuming hydrodistillation, the analyses of volatile components in aerial parts of Echinophora platyloba DC was carried out by a simple microwave distillation followed by headspace single drop microextraction (MD-HS-SDME) coupled to gas chromatography-mass spectrometry (GC-MS). The headspace volatile compounds were collected after irradiation using a single drop of n-heptadecan. The extraction conditions were optimised using the relative peak areas as index. The chemical composition of the MD-HS-SDME extracts was confirmed according to their retention indexes and mass spectra. Fifty-three components were extracted and identified by using the MD-HS-SDME method. E-β-ocimene (53.81%), R-d-decalactone (12.75%), α-pinene (6.43%), n-heptanol (6.27%), β-phellanderne (2.70%) and linalool (1.89%) were the major constituents. © 2012 Elsevier Ltd. All rights reserved. Source

Mahmoudi Chenari H.,Urmia University | Mahmoudi Chenari H.,Maraghe University | Hassanzadeh A.,Urmia University | Golzan M.M.,Urmia University | And 2 more authors.
Solid State Communications | Year: 2010

An electrical junction was fabricated in sandwich configuration from a nano- SnO2 film with a grain size of thickness 0.83 mm. The sandwich junction consisted of one monolayer between two copper electrodes. At room temperature, the Cu/nano- SnO2/Cu arrangement shows current steps similar to those of a Coulomb blockade, and a Coulomb staircase IV characteristic with asymmetric behavior, which makes it a promising candidate for use in future room-temperature single-electron transistors. While the zero-conductance gap is due to the Coulomb blockade, in good agreement with semi-classical theory, the stepplateau behavior with asymmetry in the voltage spacing and current increase can be attributed to an effect from internal energy levels. Single-electron tunneling is assumed to proceed through a double tunnel barrier junction. Impedance spectroscopy was also performed within a wide frequency range from 1 Hz to 1 MHz. © 2010 Elsevier B.V. All rights reserved. Source

Gholivand M.B.,Razi University | Abolghasemi M.M.,Razi University | Abolghasemi M.M.,Maraghe University
Chemija | Year: 2012

Te characterization of an optical sensor membrane is described for the determination of sulfde ions based on the immobilization of methylene blue on an agarose membrane. Methylene blue is covalently bonded to a transparent epoxy activated aga-rose flm. Tis optode has a linear range of 6.8 × 10 -6 - 7 × 10 -3 mol L -1 at 620 nm. Te response time of the optode is about 3 min depending on the concentration of sulfde ions. Te sensor can readily be regenerated with water, and the color is fully reversible. Te sensor was successfully used to the determination of sulfde in water. Te sulfde optical sensor was mounted in a fow cell and successfully applied for on-line sulfde monitoring. No evidence of leaching of the dye or any signal drif was observed. © 2012 Lietuvos mokslu̧ akademija. Source

Gholivand M.B.,Razi University | Abolghasemi M.M.,Razi University | Abolghasemi M.M.,Maraghe University
Journal of Separation Science | Year: 2012

Highly porous polyaniline/hexagonally ordered silica sorbent was used for fabrication of the inside needle capillary adsorption trap (INCAT) device. Polyaniline/SBA-15 nanocomposite was synthesized via chemical polymerization technique. The fabricated INCAT device was evaluated to the extraction of some polycyclic aromatic hydrocarbons (PAHs) from aqueous sample solutions in combination with gas chromatography (GC)-mass spectrometry (MS). A one at-the-time optimization strategy was applied for optimizing the important extraction parameters such as extraction temperature, extraction time, ionic strength, sampling flow rate, desorption time, and desorption temperature. In optimum conditions (extraction temperature 55°C, extraction time 20 min, ionic strength 20% (w/v), flow rate 4.5 mLmin -1, desorption temperature 270°C, desorption time 3 min) the repeatability for one INCAT device (n = 4), expressed as relative standard deviation, was between 4.2 and 10.2% for the tested compounds. The quantitation limits for the studied compounds were between 1 and 5 pgmL -1. The developed method was successfully applied to spring water sample which was spiked with PAHs with the relative recovery percentages of 87.3-109.1%. The developed method offers the advantage of being simple to use, with shorter analysis times, lower cost of equipment, and thermal stability. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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