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مرکز اطلاعات علمی SID1
مرکز اطلاعات علمی SID
اسکوپوس
مرکز اطلاعات علمی SID
ریسرچگیت
strs
Author(s): 

HACHI M. | HACHI B.

Issue Info: 
  • Year: 

    2009
  • Volume: 

    3
  • Issue: 

    3
  • Pages: 

    1-6
Measures: 
  • Citations: 

    0
  • Views: 

    25868
  • Downloads: 

    27333
Abstract: 

We theoretically show that the critical temperature Tc of the critical phenomena described within the Gibbs distribution is varying linearly with the energetic parameters of the Hamiltonian. This kind of variation is due to the nature of the competition between the energy of the system and the energy kBT the thermic source. The change of this competition will lead to a different variation of the critical temperature. This linear variation has been reported by well-known theories of the simplest Ising model. In this study, we observe that this linearity concerns all well-known magnetic Hamiltonians formulated through spin-spin interactions. This competition has also a direct effect on the class of universalities in critical phenomena.

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Author(s): 

POURHOSSEINI S. | GHASEMIZAD A.

Issue Info: 
  • Year: 

    2009
  • Volume: 

    3
  • Issue: 

    3
  • Pages: 

    7-14
Measures: 
  • Citations: 

    0
  • Views: 

    17417
  • Downloads: 

    24114
Abstract: 

In this article, the physical concepts and effective parameters on direct drive have been studied. For achieving to a high core gain we have been studied central spark ignition. In isobaric model of central spark ignition we have been obtained the conditional of hot spot formation and energy gain. In isochoric model of central spark ignition we have been gained fuel gain. Finally we have been studied fast ignition and gained fuel gain.

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Author(s): 

KHOJIER K. | SAVALONI H.

Issue Info: 
  • Year: 

    2009
  • Volume: 

    3
  • Issue: 

    3
  • Pages: 

    15-19
Measures: 
  • Citations: 

    0
  • Views: 

    36722
  • Downloads: 

    9250
Abstract: 

Nitrogen ions of 10 keV with different fluxes ranging from 5 × 1017 to 2 × 1018 ions/cm2 were implanted in Ti thin films of 61.5 nm thickness deposited on glass substrate, by means of electron beam evaporation. X-ray diffraction (XRD) and atomic force microscope (AFM) were used to obtain the crystallographic characteristics and the surface morphology of the samples, respectively. Rutherford Back Scattering (RBS) technique was employed, in order to obtain film thickness and also investigate the N+ ions distribution in Ti thin films. Average electrical resistance of the samples was measured by four point probe method. The results showed that, V-Ti4N3-x phase of Titanium nitride is formed with N+ ion implantation, and intensity of this peak increased with N+ ion flux. Furthermore, grain size, surface roughness and average resistance of samples were also increased with N+ flux. RBS spectra of the samples showed that both film thickness and the film density increased with N+ ion flux. An explanation on the ion implanation process is given for this observation.

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Issue Info: 
  • Year: 

    2009
  • Volume: 

    3
  • Issue: 

    3
  • Pages: 

    20-26
Measures: 
  • Citations: 

    0
  • Views: 

    20905
  • Downloads: 

    22735
Abstract: 

Solvent extraction is a commercial method for production of pure materials such as zirconium and hafnium and their compounds from multi-component scrubber solution. In the extraction of zirconium and hafnium salts from HNO3, HCl, HClO4 and H2SO4 into neutral organophosphorus compounds (NOPC) - such as tributyl phosphate (TBP)- in case using mixtures of inorganic acids, NOPC extracts zirconium and hafnium with separation factor considerably exceeding the corresponding value for extraction from solution of individual acids. A still higher separation level is obtained when using mixture of acids, especially those of nitric-hydrochloric acids. In this paper, the extraction of zirconium from solution containing nitric-hydrochloric acids using TBP in treated kerosene as diluents has been studied. The following parameters have been investigated: effect of extractant, nitric-hydrochloric acids and zirconium concentrations, mixing time, acidification of organic phase, the organic/aqueous phase ratio and temperature on the extraction of zirconium.

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Author(s): 

GOLNABI H. | KIANI MAJD M.

Issue Info: 
  • Year: 

    2009
  • Volume: 

    3
  • Issue: 

    3
  • Pages: 

    27-30
Measures: 
  • Citations: 

    0
  • Views: 

    18258
  • Downloads: 

    22793
Abstract: 

In this paper the output beam images and intensity profiles of an optical fiber are investigated by imaging technique. Different experiments are performed for the given fiber and captured images for the white LED and red LED sources are compared. The real-time images are investigated for two types of light sources and major differences are discussed. The effect of the light source frequency bandwidth on image formation is also investigated and obtained image patterns are discussed in detail. The resulting field intensity distributions and their relative changes with respect to the illumination source are examined and the role of fiber parameters in image cross sections is discussed. Two major differences are observed in terms of base width and FWHM bandwidth of the intensity curves for white and red LED lights. The white light LED source intensity curve shows a wider bandwidth in comparison with the red light LED intensity profile for the same fiber transmissions.

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Author(s): 

TEHRANI NASAB S.

Issue Info: 
  • Year: 

    2009
  • Volume: 

    3
  • Issue: 

    3
  • Pages: 

    31-36
Measures: 
  • Citations: 

    0
  • Views: 

    21913
  • Downloads: 

    20218
Abstract: 

The field equations of general relativity can be derived from a stationary action principle. But these equations are not unique; they may be modified by adding, for example, a second order curvature term to the gravitational action. The inclusion of one such a small corrective term leads to a set of equations with four new terms (which involve up to the fourth derivative of the scale factor). When we consider the case of a radiation-filled universe, it turns out that the effects of these new terms cancel if we adhere to the Robertson-Walker mertic (which has built into it the observed features of homogeneity and isotropy). We find R(t)=Ö1(1+ltp) and R(t)=bÖt to be equally valid solutions of the modified field equations (where R(t) is the scale factor and b and l are constants; l is very much smaller than b; p =-1). Only the first and second derivatives of R turn out to be non-vanishing. The Robertson- Walker cosmology survives our modifications even for times that are long compared with the Planck time.

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Issue Info: 
  • Year: 

    2009
  • Volume: 

    3
  • Issue: 

    3
  • Pages: 

    37-41
Measures: 
  • Citations: 

    0
  • Views: 

    33398
  • Downloads: 

    29646
Abstract: 

Copper nitride films were prepared on glass by reactive direct current magnetron sputtering at various Ar/N2 contents at room temperature. Optical reflectance and transmittance spectra have been obtained in the range 200-2000 nm. The optical properties of the deposited films are influenced by the N2 partial pressure significantly. The optical transmittance of the films increases with increasing the nitrogen contents. Also by increasing the amount of nitrogen in working gas, the optical absorption coefficient of Cu3N films was increased. The optical band gap of the films is estimated by the absorption coefficients values at the absorption edge using Tauc's procedure. For deposited films both real (n) and imaginary (k) parts of the complex refractive index are calculated.

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Issue Info: 
  • Year: 

    2009
  • Volume: 

    3
  • Issue: 

    3
  • Pages: 

    42-45
Measures: 
  • Citations: 

    0
  • Views: 

    18551
  • Downloads: 

    22121
Abstract: 

The process of development of a new code to generate design parameters of the RFQ (Radio Frequency Quadruple) has been presented. With this routine the geometry of the tips of the RFQ can be calculated. The code is written in C++ under Linux to allow for future developments for high performance calculations of the beam dynamics including space charge effects.

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