Isfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-69573420200202Structure and physical properties of layered ferrofluidsStructure and physical properties of layered ferrofluids2572731475FAM. GhominezhadM. AkhavanJournal Article20200202We have successfully synthesised and studied the bilayer ferrofluids with sodium oleate C18H33O2-Na+ as the first layer and sodium dodecyle sulfate C12H25Na+SO-4 (SDS) as the second layer surfactants. The solid phase of the ferromagnetic colloidal system was formed based on quick chemical growth. The adsorption of oleate molecule on the surface of the solid solution has been investigated by IR spectroscopy. The XRD analysis of the oxides and titration by KMnO4 show that the closest stoichiometry of Fe3O4 is achieved by the increase of Fe3+/Fe2+ molar ratio up to 2/3 with extra acidifying for prevention of uncontrolled Fe2+ excitation. The X-ray diffraction and magnetic measurements by VSM were employed for determining the particle magnetic and crystal sizes. The particle size was determined to be 9-13 nm. The magnetisation measurement of the ferrofluid indicate a saturation magnetisation of about 1.5 emu/g and reduced initial susceptibility of 6 10-3 Oe-1, which are the proper values for a superparamagnet. However, the saturation magnetisation shows a local maxima at SDS concentration about 0.07M, which is different from the behaviour presented by the mono-layer ferrofuids.We have successfully synthesised and studied the bilayer ferrofluids with sodium oleate C18H33O2-Na+ as the first layer and sodium dodecyle sulfate C12H25Na+SO-4 (SDS) as the second layer surfactants. The solid phase of the ferromagnetic colloidal system was formed based on quick chemical growth. The adsorption of oleate molecule on the surface of the solid solution has been investigated by IR spectroscopy. The XRD analysis of the oxides and titration by KMnO4 show that the closest stoichiometry of Fe3O4 is achieved by the increase of Fe3+/Fe2+ molar ratio up to 2/3 with extra acidifying for prevention of uncontrolled Fe2+ excitation. The X-ray diffraction and magnetic measurements by VSM were employed for determining the particle magnetic and crystal sizes. The particle size was determined to be 9-13 nm. The magnetisation measurement of the ferrofluid indicate a saturation magnetisation of about 1.5 emu/g and reduced initial susceptibility of 6 10-3 Oe-1, which are the proper values for a superparamagnet. However, the saturation magnetisation shows a local maxima at SDS concentration about 0.07M, which is different from the behaviour presented by the mono-layer ferrofuids.https://ijpr.iut.ac.ir/article_1475_c8143b804376a90f6ca0e577edfadc05.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-69573420200202Helmholtz free energy and equation of state of an fcc crystal with the interaction of hard sphere Yukawa potentialHelmholtz free energy and equation of state of an fcc crystal with the interaction of hard sphere Yukawa potential2752791476FAM. MoradiH. ShahriJournal Article20200202 The Helmholtz free energy and equation of the state of an fcc crystal are calculated, where the interaction between the molecules is hard sphere-Yukawa potential. Here the perturbational density functional method is used. This method is introduced by Ebner and co-workers. In this method the density functional Taylor expansion is applied for the crystal configuration up to second order. And for the uniform parts an exact expression is used. The results are compared with those obtained by Monte Carlo computer simulation. The agreement is good. The Helmholtz free energy and equation of the state of an fcc crystal are calculated, where the interaction between the molecules is hard sphere-Yukawa potential. Here the perturbational density functional method is used. This method is introduced by Ebner and co-workers. In this method the density functional Taylor expansion is applied for the crystal configuration up to second order. And for the uniform parts an exact expression is used. The results are compared with those obtained by Monte Carlo computer simulation. The agreement is good.https://ijpr.iut.ac.ir/article_1476_d845af3d66881ad9bca68f2f5562b3f3.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-69573420200202QCD model and comparison with the results of e+e- of annihilation in 60 GeV centre of mass energyQCD model and comparison with the results of e<sup>+</sup>e<sup>- </sup>of annihilation in 60 GeV centre of mass energy2812871477FAW. HayatiM. E. ZomorrodianH. SharafiM. KhosraviJournal Article20200202 We present the QCD models based on the hadronization of final states of e+e- annihilations, in 60 GeV centre of mass energy in the AMY detector at the KEK collider TRISTAN. To achieve this, we first find the jet axis by using the momentum tensor and diagonilizing it for each event. The models under consideration are the Webber, the Matrix Elements and the Parton Shower. In most cases our results are consistent with the models. Our results are also consistent with those obtained from other experiments. We present the QCD models based on the hadronization of final states of e+e- annihilations, in 60 GeV centre of mass energy in the AMY detector at the KEK collider TRISTAN. To achieve this, we first find the jet axis by using the momentum tensor and diagonilizing it for each event. The models under consideration are the Webber, the Matrix Elements and the Parton Shower. In most cases our results are consistent with the models. Our results are also consistent with those obtained from other experiments.https://ijpr.iut.ac.ir/article_1477_ce6d22aad9b83b64ca053c8617148cde.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-69573420200202Energy eigenvalues of carriers in rectangular quantum wires with spatially effective massEnergy eigenvalues of carriers in rectangular quantum wires with spatially effective mass2892931478FAE. SadeghiJournal Article20200202 Energy eigenvalues of carriers have been calculated for rectangular quantum wires with finite barrier potentials using the effective mass approximation. and systems are considered, and a spatially dependent effective mass is included in effective mass approximation. Calculated values are compared with those obtained earlier by other methods. Experimental values of the energy shift of wires are also compared with the calculations. Energy eigenvalues of carriers have been calculated for rectangular quantum wires with finite barrier potentials using the effective mass approximation. and systems are considered, and a spatially dependent effective mass is included in effective mass approximation. Calculated values are compared with those obtained earlier by other methods. Experimental values of the energy shift of wires are also compared with the calculations.https://ijpr.iut.ac.ir/article_1478_c745007effce3a1bca4d401243754a52.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-69573420200202Heavy meson fragmentation at LHCHeavy meson fragmentation at LHC2952991479FAM. A. Gomshi NobaryM. DoustiJournal Article20200202 Large Hadron Collider (LHC) at CERN will provide excellent opportunity to study the production and decay of heavy mesons and baryons with high statistics. We aim at the heavy mesons in this work and calculate their fragmentation functions consistent with this machine and present their total fragmentation probabilities and average fragmentation parameters. Large Hadron Collider (LHC) at CERN will provide excellent opportunity to study the production and decay of heavy mesons and baryons with high statistics. We aim at the heavy mesons in this work and calculate their fragmentation functions consistent with this machine and present their total fragmentation probabilities and average fragmentation parameters.https://ijpr.iut.ac.ir/article_1479_849594eecc402d506600fefe4a1a3818.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-69573420200202Electrostatics in wormhole spacetimesElectrostatics in wormhole spacetimes3013081480FAB. Nasr EsfahaniJournal Article20200202 Regarding the static form of Maxwell’s equations in wormhole background geometry, we obtain a generalised form of Laplace’s equation. Because of peculiar geometry of the throat, lines of force that enter the wormhole at one mouth and emerge from the other, initially converge and then diverge. So, for a remote observer the wormhole can act as a charge distribution that modifies the potential, mainly around the throat. Here, the exact solutions for the potential are obtained and by considering an equivalent dielectric media and finding polarisation charge distributions the effect of the wormhole geometry on the potential is justified. It is assumed that real sources of the potential are distributed far from the throat and do not contribute to the stress-energy tensor of the wormhole. Regarding the static form of Maxwell’s equations in wormhole background geometry, we obtain a generalised form of Laplace’s equation. Because of peculiar geometry of the throat, lines of force that enter the wormhole at one mouth and emerge from the other, initially converge and then diverge. So, for a remote observer the wormhole can act as a charge distribution that modifies the potential, mainly around the throat. Here, the exact solutions for the potential are obtained and by considering an equivalent dielectric media and finding polarisation charge distributions the effect of the wormhole geometry on the potential is justified. It is assumed that real sources of the potential are distributed far from the throat and do not contribute to the stress-energy tensor of the wormhole.https://ijpr.iut.ac.ir/article_1480_cd28f5b660db380380293509cacb1811.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-69573420200202Selection of candidate sites for Iranian national observatory by wind-rose studiesSelection of candidate sites for Iranian national observatory by wind-rose studies3093151481FAS. NasiriA. AbediniJournal Article20200202 The site selection procedure for optical observatories housing a telescope with a sizeable aperture is described. The theory of seeing is briefly introduced and a special type of seeing monitor that is widely used for seeing measurements is discussed. The results of the meteorological studies mainly based on the wind-rose diagrams are presented. These are done for 31 preliminary selected candidate sites using the data obtained from meteorological synoptic stations during the last 20 years. The site selection procedure for optical observatories housing a telescope with a sizeable aperture is described. The theory of seeing is briefly introduced and a special type of seeing monitor that is widely used for seeing measurements is discussed. The results of the meteorological studies mainly based on the wind-rose diagrams are presented. These are done for 31 preliminary selected candidate sites using the data obtained from meteorological synoptic stations during the last 20 years.https://ijpr.iut.ac.ir/article_1481_eb55beadd7c1fdf16ec1b2600f75f36a.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-69573420200202Calculation of rotational structure of CF4 molecule by using J Moret-Bailly theoryCalculation of rotational structure of CF<sub>4 </sub>molecule by using J Moret-Bailly theory3173221482FAE. JaafariJournal Article20200202 Here we study the rotational structure of CF4 molecule for ground state n 4 mode, fine structure step by using J. Moret-Bailly theory. First the calculated spectra are normalized to the experimentally measured spectra, for calculating the centrifugal and coriolis constants up to the third approximation, D =-3.18 ´ 10-3 cm-1, (4) x = 1.33 ´ 10-1 cm-1. Then the rotational energies are calculated for J £ 6. Here we study the rotational structure of CF4 molecule for ground state n 4 mode, fine structure step by using J. Moret-Bailly theory. First the calculated spectra are normalized to the experimentally measured spectra, for calculating the centrifugal and coriolis constants up to the third approximation, D =-3.18 ´ 10-3 cm-1, (4) x = 1.33 ´ 10-1 cm-1. Then the rotational energies are calculated for J £ 6.https://ijpr.iut.ac.ir/article_1482_bc8de52a514fc528135e09de28d1b930.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-69573420200202MIR-difference-frequency laser spectrometer for CO detection in combustionsMIR-difference-frequency laser spectrometer for CO detection in combustions3233231483FAA. KhorsandiU. WillerP. GeiserW. SchadeJournal Article20200202 Two continuous-wave (cw) single mode diode-lasers (Toshiba TOLD 9150 and Sharp LT024MDO) are applied as pump and signal sources to obtain difference-frequency generation (DFG) in the mid-infrared (MIR) region by using an AgGaS2 crystal with a length of 30 mm for 90° type I phase-matching. Tuneable MIR laser radiation around 5 µm is obtained with an output power in the order of hundred nW while the diode lasers are operated at 20 and 30 mW around their centre wavelengths 789 and 681 nm, respectively. To demonstrate the applicability of this MIR-DFG laser spectrometer we recorded the absorption spectrum of CO for the P(21) rotational line at 2055.4 cm-1 in a 10 cm long cell and in the flame of a McKenna burner in order to estimate the self-broadening coefficient of CO, the collisional-broadening of CO with CO2, and the CO concentration distribution in the flame. Two continuous-wave (cw) single mode diode-lasers (Toshiba TOLD 9150 and Sharp LT024MDO) are applied as pump and signal sources to obtain difference-frequency generation (DFG) in the mid-infrared (MIR) region by using an AgGaS2 crystal with a length of 30 mm for 90° type I phase-matching. Tuneable MIR laser radiation around 5 µm is obtained with an output power in the order of hundred nW while the diode lasers are operated at 20 and 30 mW around their centre wavelengths 789 and 681 nm, respectively. To demonstrate the applicability of this MIR-DFG laser spectrometer we recorded the absorption spectrum of CO for the P(21) rotational line at 2055.4 cm-1 in a 10 cm long cell and in the flame of a McKenna burner in order to estimate the self-broadening coefficient of CO, the collisional-broadening of CO with CO2, and the CO concentration distribution in the flame.https://ijpr.iut.ac.ir/article_1483_97b33d3104ea0b393d51d382b8cec049.pdfIsfahan University of Technology,
The Physics Society of IranIranian Journal of Physics Research1682-69573420200202Pure SU(3) potentials in the fat-centre-vortices modePure SU(3) potentials in the fat-centre-vortices mode3243241484FAS. DeldarJournal Article20200202 The potentials between static sources in various representations in SU(3) are calculated on the basis of the fat-centre-vortices model of Faber, Greensite and Olejník. At intermediate distances, potentials are in qualitative agreement with “Casimir scaling,” which says that the string tension is proportional to the quadratic operator of the representation. At large distances, screening occurs for zero-triality representations for the representations with non-zero triality the string tension equals that of the fundamental representation. The potentials between static sources in various representations in SU(3) are calculated on the basis of the fat-centre-vortices model of Faber, Greensite and Olejník. At intermediate distances, potentials are in qualitative agreement with “Casimir scaling,” which says that the string tension is proportional to the quadratic operator of the representation. At large distances, screening occurs for zero-triality representations for the representations with non-zero triality the string tension equals that of the fundamental representation.https://ijpr.iut.ac.ir/article_1484_2180ea4fabccde65149cc4e182f05a8d.pdf