Kosar University of Bojnord

Bojnord, Iran

Kosar University of Bojnord

Bojnord, Iran
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Ghalenovi Z.,Kosar University of Bojnord | Moazzen M.,Kosar University of Bojnord
International Journal of Modern Physics E | Year: 2017

Masses and magnetic moments of N and Δ resonances are calculated employing the hyperspherical approach. We extend our scheme to obtain the helicity amplitudes and transition magnetic moments of the Δ → Nγ process. We also compute the radiative decay widths and branching ratios of Δ baryons. A comparison of our results with the predictions obtained in recent theoretical models is also presented. © 2017 World Scientific Publishing Company.


Moazzen M.,Kosar University of Bojnord
International Journal of Modern Physics A | Year: 2017

In this paper, we investigate Kalb-Ramond field localization in two types of five-dimensional braneworld models given by sine-Gordon potentials. The sine-Gordon (SG) and double sine-Gordon (DSG) branes are generated by a real scalar field coupled to gravity minimally. In both scenarios, we employ two localization mechanisms. One is the well-known dilaton coupling and the other is based on a five-dimensional Stueckelberg-like action. With two mechanisms, we find that the massless zero mode of Kalb-Ramond field is localized on the SG and DSG branes. Also, it is shown that both the mechanisms can result in a volcano-like potential of the Kalb-Ramond massive modes. Furthermore, we study the effects of the dilaton coupling constant on the mass spectrum of the Kalb-Ramond field. © 2017 World Scientific Publishing Company.


Moazzen M.,Kosar University of Bojnord | Ghalenovi Z.,Kosar University of Bojnord
Annals of Physics | Year: 2017

In this paper, we investigate localization of bulk scalar fields in two types of five-dimensional braneworld models given by sine–Gordon potentials (SG). The sine–Gordon and Double sine–Gordon (DSG) branes are employed to produce different thick brane setups. In both scenarios, we include the bulk mass and non-minimally coupled terms in the global action and obtain some implications on the volcano-like potentials of the Kaluza–Klein modes associated to the corresponding Schrödinger-like equations. Also, we find that minimally and non-minimally coupled massive bulk scalar fields can be localized on SG and DSG branes if their bulk mass obeys an upper bound. Furthermore, it is shown that at the critical value of the non-minimal coupling constant the bulk scalar field cannot be localized on the branes. © 2017 Elsevier Inc.


Sobhani A.,Kosar University of Bojnord | Salavati-Niasari M.,University of Kashan
Journal of Alloys and Compounds | Year: 2014

The cubic MnSe2/Se nanocomposites were produced under hydrothermal condition, by reduction of SeCl4 to Se and Se 2-, and reaction of the reduced selenium with Mn2+ ion during the next step, in the presence of different surfactants using hydrazine as reductant. The main factors affecting the morphology, the particle size and the phase of the products, such as surfactant, reductant and its amount, reaction temperature and time were studied. The pure Se or a mixture of Se and MnSe2 nanorods were obtained in the presence of different surfactants and small amounts of hydrazine. The cubic MnSe2/Se nanocomposites were formed at 120 °C for 12 h or longer periods of time, in the presence of polyethylene glycol (PEG) and large amounts of hydrazine. The size of the as-prepared cubes decreases with increasing the reaction time. With increasing temperature of reaction from 120 °C to 180 °C, the morphology of the products changes from cubes to the mixture of nanorods and nanoparticles. © 2014 Elsevier B.V. All rights reserved.


Sobhani A.,Kosar University of Bojnord | Salavati-Niasari M.,University of Kashan
Materials Research Bulletin | Year: 2014

In this paper, we report a convenient and controllable synthetic method based on a reaction in an aqueous system, which can produce CdSe nanostructures of different sizes and shapes at 180 C for 12 h. SeCl4 and 3CdSO 4·8H2O are used as reactants in this hydrothermal method. By using appropriate surfactants and reductants as controlling reagents and also adjusting molar ratio of Cd/Se and amount of reductant, the morphology, particle size and structural phase of products can be easily controlled. Because of high yield, simple reaction apparatus, and low reaction temperature, this method will have a good prospect in future large-scale application and surely can be used to synthesize other metal selenide nanostructures. © 2014 Elsevier Ltd.


Ansari F.,University of Kashan | Sobhani A.,Kosar University of Bojnord | Salavati-Niasari M.,University of Kashan
Journal of Magnetism and Magnetic Materials | Year: 2016

Copper hexaferrite (CuFe12O19) nanostructures were prepared by a simple route utilizing maltose-assisted sol-gel process. The morphology, phase structure, composition and purity of nanostructures can be controlled by type of surfactant and also adjusting the Cu:surfactant, Cu:Fe and Cu:reductant ratios. The bean-shape structures are formed in the absence of the surfactant when the molar ratio of Cu:Fe and Cu:reductant are 1:12 and 1:26, respectively. The agglomerated spherical nanoparticles with diameters ranging from 7 to 20 nm are obtained in the presence of triplex, when ratio of Cu:reductant is 1:26. In the absence of surfactant and also in the presence of triplex, the samples are found to be CuFe12O19. When polymer is used, there are still the peaks of CuFe12O19 and also some boad peaks in XRD patterns, because of the small size and encapsulation of nanostructures with polymer. Magnetic measurments show superparamagnetic behavior for the all samples. The Ms for the samples obtained in the presence of polymer shows that the coating of magnetic nanostructures does not always increase Ms. FT-IR frequency bands in the range 463-626, 607 and 542 cm-1 correspond to the formation of metal oxides in ferrites. © 2015 Elsevier B.V.


Sobhani A.,Kosar University of Bojnord | Salavati-Niasari M.,University of Kashan
Ceramics International | Year: 2014

In this paper copper selenide nanostructures were synthesized via a simple hydrothermal method based on the reaction between copper salt and SeCl 4 in water. The reduction reaction of SeCl4 to Se and then Se2- was carried out by three types of reductants: N 2H4.H2O, KBH4, and metallic Zn. Different compositions of copper selenides were obtained by changing the molar ratio of the precursors. At the temperature of 120 °C for a 12 h period of time, when the molar ratio of Cu/Se is 1:1 or 2:1, the product is pure and found to be CuSe and Cu1.8Se, respectively. A mixture of the different phases of copper selenides is obtained by making use of 1:2, 3:2 and 3:1 M ratios between Cu and Se. With an increasing reaction temperature up to 210 °C, the mixture of Cu3Se2 and CuSe is prepared from 1:1 M ratio of precursors. The effects of copper salt, surfactant, amount of hydrazine, reaction time and temperature on the morphology and particle size of products are also investigated. The synthesis can be performed conveniently and safely. The products are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS) analysis. Photoluminescence (PL) is used to study the optical property of copper selenides. © 2014 Elsevier Ltd and Techna Group S.r.l.


Sobhani A.,Kosar University of Bojnord | Salavati-Niasari M.,University of Kashan
Superlattices and Microstructures | Year: 2014

A series of nickel selenides (NiSe and NiSe2) has been successfully synthesized from the reaction of SeCl4 with NiCl 2×6H2O in the presence of cetyltrimethyl ammonium bromide (CTAB) as surfactant and hydrazine hydrate (N2H 4×H2O) as reductant at 180 C for 12 h through a simple hydrothermal method. The morphology, phase structure and composition of NixSey can be controlled by adjusting the Ni/Se ratio of the raw materials, the quantity of reductant, the reaction temperature and so forth. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS) analysis. It was found that when the ratio of Ni/Se is 1:1 or 3:2, flower-like assemblies of NiSe nanosheets are formed, at 180 C for 12 h. When the ratio of Ni/Se is 1:2 at 180 C, the products are found to be the mixture of hexagonal NiSe and cubic NiSe2. With decrease of nickel content in molar ratio of 1:2 (Ni:Se), nanospheres are agglomerated and microstructures are formed. With the reaction temperature decreasing from 180 C to 120 C, we reach pure NiSe2 nanoparticles. The formation mechanism of the nickel selenides has been investigated in detail by means of XRD and SEM analyses. © 2013 Elsevier Ltd. All rights reserved.


Sobhani A.,Kosar University of Bojnord | Salavati-Niasari M.,University of Kashan
Journal of Alloys and Compounds | Year: 2014

FeSe2 nanoparticles and FeSe2/FeO(OH) nanocomposites have been synthesized through a novel controllable hydrothermal method with FeSO4·7H2O and SeCl4 as precursors. In this procedure, H2SeO3 (obtained from aqueous solution of SeCl4) is gradually reduced to Se and Se2- by reductant. The reduced Se and Se2- ions are combined with Fe2+ ion to give FeSe2. By varying the surfactant, reaction time, temperature, reductant and amount of hydrazine hydrate (N2H4·H2O), the method permits us to synthesize different products. The FeSe2 nanoparticles are synthesized in the presence of PEG4000 at 140 °C for 13 h. Using PEG600 (at 140 °C or 110 °C for 13 h) and sodium dodecyl sulfate (at 140 °C for 7 h), FeSe2/FeO(OH) nanocomposites are synthesized. SEM and TEM images show the morphology and size of the as-synthesized samples. Chemical composition of the samples is characterized by XRD, XPS and EDS. Ultraviolet-visible and photoluminescence spectra exhibit optical properties of nanostructures. Magnetization measurement shows a twofold behavior, ferromagnetic and paramagnetic behaviors, for FeSe2 nanoparticles. © 2014 Elsevier B.V.


Ansari F.,University of Kashan | Sobhani A.,Kosar University of Bojnord | Salavati-Niasari M.,University of Kashan
RSC Advances | Year: 2014

A new way of preparing lead hexaferrite (PbFe12O19) nanoplates and nanoparticles has been developed using the sol-gel auto-combustion route, without adding external surfactant. For the first time, maltose has been applied as reductant to form PbFe12O19. In this work, we have chosen lead nitrate and iron nitrate as starting reagents. The morphology, phase structure, composition and phase purity of PbFe12O19 can be controlled by adjusting the Pb/Fe and Pb:reductant ratios and also calcination temperature. When the molar ratio of Pb/Fe is 1:6 and calcination temperature is 900 °C, the product is pure and found to be PbFe12O19 nanoplates. The size and agglomeration of the nanoplates increase with decreasing maltose content. On decreasing the calcination temperature to 600 °C, nanoparticles with spherical morphology are obtained. The PbFe12O19 nanostructures are characterized using SEM, TEM, EDS and XRD. Products with a high coercive force of 5609 Oe are obtained when the Pb/maltose and Pb/Fe ratios are 1:26 and 1:6, respectively, and calcination temperature is 900 °C. © 2014 The Royal Society of Chemistry.

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