فهرست مطالب

Sciences, Islamic Republic of Iran - Volume:24 Issue: 3, 2013
  • Volume:24 Issue: 3, 2013
  • 96 صفحه،
  • تاریخ انتشار: 1392/05/01
  • تعداد عناوین: 8
|
|
  • N. Seyedi, M.Kalantari Page 205
    In this work, a green, simple and highly efficient procedure for the synthesis of bis(indolyl)methanes is described. The condensation of indoles with carbonyl compounds catalyzed by citric acid in water affords bis(indolyl)methanes in high yields and relatively short reaction times. The advantages of this method are using of water as a low cost solvent and efficient recyclability of the catalyst.
    Keywords: Bis(indolyl) methane, Indole, Citric acid, Water
  • S. Pirsa, A.Afshar Asl, A.Khani, A.Allahverdi Pur Page 209
    Determination of 1, 1-dimethylhydrazine (DMH) in air is carried out by spectrophotometry, GC or HPLC analysis, but in this study DMH was analyzed by a gas sensor based on nanostructure conducting polyaniline. Determination of DMH has been done very simplely and quickly in recent work. Electrically conductive fibers have been prepared by polymerization of aniline on surfaces of commercial polymer fibers in the presence of an oxidizing agent. The resistance of poly aniline (PANI) coated fiber sensor (PANI-FS) was investigated and related to coating conditions, which was controlled by adjusting the reactant concentrations. The morphology of the conducting film on the surface of the fibers was examined by scanning electron microscope (SEM). The sensing behavior of PANI in the presence of some volatile organic compounds (VOCs) is studied experimentally. The PANI sensor had demonstrated to have good sensitivity for DMH and good reproducibility when reused.
    Keywords: Poly aniline, Gas sensor, 1, 1, dimethylhydrazine, Nanostructure
  • M. Moazzen, R.Hajialioghli, A.Moller, G.T.T.Droop, R.Oberhansli, U.Altenberger, A.Jahangiri Page 217
    U-Pb ages obtained on zircons from the investigated migmatites place new constraints on the evolution of the crustal rocks in the Takab area. SHRIMP U-Pb dating of inherited zircon in the melanosome parts of mafic migmatites from the Takab complex gives a discordant age with an upper intercept of 2961±72 Ma (MSWD=0.5) and a lower intercept of 24.2±5.7 Ma (MSWD=1.7). In the concordia diagram, the melt-grown zircons yield a more precise age of 25.67±0.74 Ma (MSWD=1.7), similar to the lower intercept age of the discordia. At least part of the scatter along the concordia for the new zircon generations may be real, caused by an extended period of melting and crystallization, in which case the oldest age of c. 29 Ma dates the onset of partial melting. The Oligocene ages for the younger zircons show the importance of partial melting in these mafic rocks. The typical euhedral to subhedral shapes are features related to crystallization and resorption of the grains due to in situ melting. These processes were most likely related to the generation of the Tertiary granitoids of the Takab complex.
    Keywords: SHRIMP dating, mafic migmatites, Takab
  • M. Nemati Page 229
    In 2012 August 11 (12:23 UTC) a moderate earthquake with MW=6.4 (USGS) occurred between Ahar and Varzaghan towns in Azarbayjan Province at northwest of Iran. After eleven minutes another earthquake shook the area with MW=6.2 (USGS). These consecutive earthquakes followed by intensive sequences of aftershocks whereas the strongest one had MW=5.3 (USGS). In data processing including depth modification and focal mechanism solution, we used regional (Institute of Geophysics, University of Tehran (IGUT) and International Institute of Earthquake Engineering and seismology (IIEES) of Iran) and worldwide (ISC) seismological data. After processing westward fault propagation estimated using Building and House Research Center (BHRC) of Iran strong-motion records. Also depth of the mainshocks and some important aftershocks modified using pP phase travel times recorded with ISC stations (10-14 km) which are nicely situated in seismogenic part of crustal structure of the area. The focal mechanisms processed using first P motion method for the two mainshocks and dominant mechanisms calculated for the intense aftershocks (MN>4.0, IGUT) manifestly displayed a strike-slip movement on a steep south dipping nodal plane with near E-W strike without any interpretation using earthquakes location. These are associated with the Geological Survey of Iran (GSI) field observations.
    Keywords: Earthquake, Focal mechanism, Aftershocks, Strike, slip, Steep dipping
  • J.Noorbakhsh Razmi, A.A.Aryaei, M. Taherpour Khalil Abad, A.R.Ashouri Page 243
    Abderaz Formation is one of the Upper Cretaceous formations in the Kopet-Dagh sedimentary basin. A stratigraphic section from the mentioned formation is selected for detailed systematic description with regard to echinoids. Numerous well preserved representatives of the families Mircrasteridae wright, 1857 and Echinocorythidae Lambert, 1920 are described from the Ghaleh-Zoo stratigraphic section in the Kopet-Dagh sedimentary basin, northwest of Shirvan township (NE Iran). The age of the fossil assemblage is determined as Turonian-Santonian based on four echinoid species: Micraster (Micraster) coranguinum Leske, 1778, Micraster (Micraster) cortestudinarium (Goldfuss, 1829), Echinocorys gravesi (Agassiz & Desor, 1847) and Echinocorys ex gr. scutata Leske, 1778.
    Keywords: Echinoids, Late Cretaceous, Kopet, Dagh, NE Iran
  • G. H. Shirdel Shirdel, N.Kahkeshani Pages 269-273
    In the maximum flow network interdiction problem, an attacker attempts to minimize the maximum flow by interdicting flow on the arcs of network. In this paper, our focus is on the nodal interdiction for network instead of the arc interdiction. Two path inequalities for the node-only interdiction problem are represented. It has been proved that the integrality gap of relaxation of the maximum flow network interdiction problem is not bounded below by a constant, even when strengthened by the path inequalities. We show that this result is also established for the nodal interdiction problem.
    Keywords: Nerwork flows, Nodal interdiction, Path inequalities
  • A.Zare, A. Golchin, H.Mohammadzadeh Page 275
    In this paper firt of all we introduce a generalization of torsion freeness of acts over monoids, called -torsion freeness. Then in section 1 of results we give some general properties and in sections 2, 3 and 4 we give a characterization of monoids for which this property of their right Rees factor, cyclic and acts in general implies some other properties, respectively.
    Keywords: R, torsion free, Rees factor act, cyclic act