فهرست مطالب

Journal of Nano Structures
Volume:2 Issue: 1, Winter 2012

  • تاریخ انتشار: 1391/01/20
  • تعداد عناوین: 16
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  • A. R. Badiei*, G. Mohammadi Ziarani, A. R. Abbasi, M. Jafarabadi Pages 1-7
    The phenylthiourea-substituted triethoxysilane as a silane agent was synthesized and grafted on highly ordered nanoporous silica (LUS- 1) with a textured morphology and hexagonal array. This material (Tu-LUS-1) contained 0.8 mmol/g of soft base phenylthiourea group and surface area 760 m2g-1 and was able to adsorb 0.75 mmolHg/g of TU-LUS-1 in endothermic reaction.
    Keywords: Nanoporous silica, Water pollution, LUS, 1, MCM, 41, Mercury, Heavy metal ion
  • A. Tadjarodi *, H. Kerdari, M. Imani Pages 9-17
    Cadmium oxide rhombus-shaped nanostructure was synthesized using hydrothermal process followed by heating treatment. Clearly, X-ray diffraction pattern demonstrated the formation of CdO crystalline phase. Scanning electron microscopy (SEM) showed that the obtained rhombus-like structure is composed of nanoparticles with the average size of 29 nm. In addition, we evaluated adsorption of organic dye i.e. Congo red from water using the prepared CdO rhombus like microstructure. UV-visible absorption spectroscopy was used to record the adsorption behavior. It was found that the removal process is performed via electrostatic absorption mechanism. The maximum adsorption capacity of CdO rhombus structures (0.01 g) for Congo Red (CR) in the concentration range (5-50 mg L-1) studied, as calculated from the Langmuir isotherm model at 25 °C and neutral pH, was found to be 41.20 mg g−1.
    Keywords: Nanostructures, Semiconductor, Adsorption, Cadmium oxide, Congo Red
  • M. Malekshahi Byranvand*, A. Nemati Kharat, A. R. Badiei Pages 19-26
    The dye-sensitized solar cells (DSSC) have been regarded as one of the most promising new generation solar cells. Tremendous research efforts have been invested to improve the efficiency of solar energy conversion which is generally determined by the light harvesting efficiency, electron injection efficiency and undesirable electron lifetime. In this review, various characteristics of dyesensitized nanostructured TiO2 solar cells, such as working principle, electron transport and electron lifetime, were studied. The review avoids detailed mathematical and spectroscopic discussion, but rather tries to summarize the key conclusions relevant to materials design.
    Keywords: Dye, Sensitized Solar Cells (DSSC), Electron transport, Nanostructured TiO2, Electron lifetime, Nanocrystal
  • F. Bustanafruz, M. Jafar, Tafreshi*, M. Fazli Pages 27-33
    Ammonium carbonate and ammonium sulfate have been proposed and used as two new fuels for synthesizing gamma alumina nanoparticles. The prepared samples have been characterized by X-ray diffraction (XRD), 2 N adsorption (BET) and Transmission electron microscopy (TEM). A comparison has been made between the properties of the nanoparticles synthesized by these two fuels and other conventional fuels. These two mineral fuels showed to be suitable for replacing organic fuels in combustion synthesis because they reduce the size and increase specific surface area of alumina nanoparticles effectively.
    Keywords: Alumina, Nanoparticles, Solution combustion synthesize, Mineral fuels, Specific surface area
  • P. Nooraei, B. Shareghi*, M. Salavati, Niasari, H. R. Shahbazkiaa, A. Semnani Pages 35-41
    The interaction of copper oxide nanoparticles and copper ions and proteinase K from Tritirachium album Limber has been investigated employing UV spectroscopy and kinetics measurements. The aim of this study was to evaluate the effect of nanoparticles of CuO for proteinase K. In this paper we compare the effect of copper oxide nanoparticles with the effect of copper ions on proteinase K stability and activity. Copper oxide nanoparticles had more inhibitory and destabilization effect than copper ions on proteinase K. We used thermodynamic parameter such as Tm and ΔG0 and kinetic studies to emphases the effect of nanoparticles CuO and copper ions on stability and activity of proteinase-K.
    Keywords: Proteinase, K, Copper oxide, Nanoparticles, Thermodynamic parameter, Nanostructures
  • M. Masteri, Farahani* Pages 43-50
    Covalent grafting of the nanoporous molecular sieve MCM-41 with 3- aminopropyl trimethoxysilane and acetyl acetone (acac) successively gave modified MCM-41 (acacAmpMCM-41). Reaction of the resulted material with glycine afforded the corresponding supported glycine Schiff base ligand and subsequent reaction with [bis(acetylacetonato)dioxomolybdenum(VI)] was lead to molybdenum complex supported on MCM-41 through propyl chain spacer.Characterization of the resulting material was carried out with FT-IR, atomic absorption spectroscopy, powder X-ray diffraction and BET nitrogen sorption methods. The XRD and BET analyses revealed that textural properties of support were preserved during the grafting experiments. The resulted material successfully catalyzed the epoxidation of olefins with tert-butyl hydroperoxide to the corresponding epoxides.
    Keywords: Molybdenum, MCM, 41, Epoxidation, Glycine, Schiff base
  • A. A. Abbasian, G. A. Sheikhzadeh, R. Heidary, N. Hajialigol *, M. Ebrahim, Qomi Pages 51-60
    In the present study, mixed convection laminar flow around an adiabatic body in a Lid-driven enclosure filled with nanofluid using variable thermal conductivity and variable viscosity is numerically investigated. The fluid around the body in the enclosure is a waterbased nanofluid containing Al2O3 nanoparticles. The Vertical enclosure’s walls are maintained at constant cold temperature and the horizontal bottom enclosure’s wall is kept constant at hot temperature. Top enclosure’s wall is insulated and moving with uniform velocity. The ratio of body’s length to enclosure’s length is kept constant at 1/3. The study has been carried out for the Richardson number of 0.01 to 100, the solid volume fraction of 0 to 0.06 and the Grashof number of 104. Various results for the streamlines and isotherms as well as the local and average Nusselt numbers are presented. By the use of variable properties in this study Interesting results are observed.
    Keywords: Variable properties, Lid, driven enclosure, Mixed convection, Nanofluid, Enclosure with body
  • G. A. Sheikhzadeh, M. Ebrahim Qomi, N. Hajialigol*, A. Fattahi Pages 61-68
    The fluid flow and heat transfer in a three-dimensional microchannel filled with Al2O3- water nanofluid is numerically investigated. The hybrid scheme is used to discretize the convection terms and SIMPLER algorithm is adopted to couple the velocity and pressure field in the momentum equations. The temperature fields, variation of horizontal velocity along the centre line of the channel, average Nusselt number and the thermal resistance in different aspect ratios are presented. It is observed that aspect ratio mainly affected the temperature gradient as well as heat transfer. Analyzing the results of numerical simulations indicates that with increasing aspect ratio, horizontal velocity along the centre line increased and then, average Nusselt number and the inlet and outlet thermal resistance decrease in the microchannel.
    Keywords: Mixed convection, Microchannel, Nanofluid, Microchannel, Alumina
  • A. Akbari *, A. Yunessnia Lehi, M. Bojaran Pages 69-77
    Poly(vinylidene fluoride) (PVDF) nanofibers were prepared via electrospinning process. Several different factors influence on this process and application of experimental design for its optimization is of great importance. The central composite design (CCD) was used for planning and optimizing of the experiments and also, the analysis of variance (ANOVA) was employed for the statistical validation of regression models. In this research, we found optimal condition for the effects of four factors, i.e. PVDF concentration, flow rate, voltage and interval on the fiber diameter. The model indicated that the flow rate (negatively) and solution concentration (positively) influence extremely on the fiber diameter, whereas the voltage and interval influence equally together on the response (negatively).
    Keywords: Central Composite Design, Electrospinning Process, Expert Design, Nanofibers, Optimization, Poly(vinylidene fluoride)
  • J. Safaei, Ghomi*, S. Rohani, A. Ziarati Pages 79-83
    CuI nanoparticles as an expedient and recyclable catalyst for the synthesis of N-cyclohexyl-3-aryl-quinoxaline-2-amines in ethanol via a multi-component reaction are established. The products were separated from the catalyst simply by filtration. The catalyst could be recycled and reused for several times without noticeably decreasing the catalytic activity.
    Keywords: CuI, nanoparticles, Multi, component reactions, Heterogeneous catalyst, One, pot
  • M. Najafi, A. Abbasi*, A. Badiei Pages 85-100
    A number of redox-active coordination polymers (CPs) or metalorganic frameworks (MOFs) have been successfully synthesized using transition metals and bridging ligands. This article aims to deal with gathering the aforementioned disperse issues regarding the electroactive CPs. It also goes towards illustrating the effects of various factors on the electrochemical behavior of CPs including nature of the ligand and its substitutes, metal centers, nanoporous coordination cages, coordinating atoms, solvent and temperature. Electrochemical investigations of CPs could bring insights into metal interactions and electronic communications caused by π-conjugated backbone insights into metal interactions and electronic communications caused by π-conjugated backbone of the bridging ligand. Furthermore, some fundamental aspects of electrochemistry and a few interesting applications of CPs will be addressed in this paper.
    Keywords: Metal‐organic, Polymer, Nanostructure, Electrochemical behavior, Cyclic voltammetry
  • A. Bamoniri*, B. F. Mirjalili, S. Nazemiana Pages 101-105
    Two simple protocols for the synthesis of 1, 2, 4, 5- tetrasubstitutedimidazoles using nano-SPA as a reusable, ecofriendly, inexpensive, and efficient catalyst are reported. Short reaction times, high yields, scale-up and easy workup are the advantages of these protocols.
    Keywords: Tetrasubstitutedimidazoles, Multi, component reactions, Nano silica, Phosphoric acid, Sonication condition
  • A. Hojabri, F. Hajakbari, M. A. Moghri Moazzen*, S. Kadkhodaei Pages 107-112
    Copper thin films with nano-scale structure have numerous applications in modern technology. In this work, Cu thin films with different thicknesses from 50–220 nm have been deposited on glass substrate by DC magnetron sputtering technique at room temperature in pure Ar gas. The sputtering time was considered in 4, 8, 12 and 16 min, respectively. The thickness effect on the structural, morphological and electrical properties were studied by X-ray diffraction (XRD), atomic force microscope (AFM) and four point probe (FPP) measurements, respectively. The results show that by increasing thickness, the copper films crystallinity in (111) direction increases. Also by varying the films thickness the significant changes were observed in the films surface morphology due to the mechanism of films growth. Finally, the relationship between film resistivity and Cu film thickness are investigated in this paper.
    Keywords: Copper Thin film, Nanoscale, Thickness, Morphology, Resistivity
  • A. Ghorbanpourarani *, A. Haghshenas, S. Amir, M. Azami Pages 113-124
    Electro-thermo-elastic stress analysis of piezoelectric polymeric thick-walled cylinder reinforced by boronnitride nanotubes (BNNTs) subjected to electro-thermo-mechanical fields is presented in this article. The electro-thermo-elastic properties of piezoelectric fiber reinforced composite (PEFRC) was studied by a modified XY micromechanical model capable of exhibiting full coupling relation between electric, thermal and elastic fields. Assuming the basic relation for the axisymmetric deformation of a thick-wall cylinder subjected to uniform internal and external pressures, an axial electrical load, a temperature change ΔT between inner and outer radius are derived. The stress results suggest that increasing BNNTs content in longitudinal direction reduces the effective stress. Also, displacement along radial direction indicates an optimum content of 5% BNNT for this. Furthermore, at normal working conditions, the influence of thermal and mechanical fields are much higher than the electric one on the effective stress; hence, this smart structure is best suited for applications as sensors than actuators.
    Keywords: Boron Nitride Nanotube, Piezoelectric cylinder, Electro, thermo, mechanicalanalysis, Micromechanical model
  • P. Sadeghi, Alavijeh, M. Monemzadeh*, N. Tazimi Pages 125-129
    In this paper, using Monte Carlo Fortran code, we have obtained the binding energies for three different systems of diquark–antidiquark in distances from 0.01 to 15 nm. In [0.1 - 15] nm interval, we made use of Coulomb potential because in this interval, strong interaction is negligible. We have compared the binding energies of the systems with one another. The results of these comparisons were close to our anticipations. We also obtained the binding energy of one of the systems in the interval below 1 fm, where diquark-antidiquark systems comprise a tetraquark and the potential is of strong interaction type. Because of weak Coulomb interaction, strong interaction has been used as the basis of the calculations. The binding energy resulted is consistent with the existing references.
    Keywords: Tetraquark System, Lippman, Schowinger, Equation, Binding Energy
  • M. Zahedifar *, Z. Chamanzadeh Pages 131-137
    Tm3+, Yb3+ and Tm3+/Yb3+ doped LaVO4 nanostructures were synthesized for the first time by using the hydrothermal method with the aid of La(CH3CO2)3 as lanthanum source in presence of oleic acid as surfactant. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL) spectroscopy and UV– Vis diffuse reflectance spectroscopy. Besides, the effects of activator concentration and sensitizer on the emission intensity were investigated. The PL spectrum revealed that the emission intensity decreases with increase in the concentration of Tm3+, while adding Yb3+ as sensitizer causes the emission intensity to increase. The LaVO4: Tm3+/Yb3+ may possibly have potential application in enhancing the conversion efficiency of dye-sensitized solar cells by increasing the absorption of dyes.
    Keywords: LaVO4 Tm3+, Yb3+, Nanosheets, Downconversio, Nanostructures, Hydrothermal