فهرست مطالب

  • Volume:2 Issue:4, 2009
  • تاریخ انتشار: 1387/12/11
  • تعداد عناوین: 8
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  • Jamali Sheini, Peleman Al Tabbakh, Joag, More Page 1
    Cu/ZnO nanostructures have been synthesized by cathodic electrodeposition technique. The field emission characteristics of the as-synthesized films, obtained by planar diode configuration, showed high emission current and stable field emission over long hours of operation. The analysis of the field emission characteristics, based on variationof the Fowler-Noedheim plots parameters and SEM images, suggests an emission evolution during operation time. The evolution of the field emission is explained on the basis of the field induced diffusion/activation of the Cu nanoparticles.
  • Kashani, Miyamoto, Tanimura Page 6
    The calibration procedure of silver activation detectors using a mono energetic neutron source with 5MeV beam energy at FRS of JAERI (Japan Atomic Energy Research Institute) is described in this paper. These detectors are fabricated for measuring fusion neutron burst emitted of z-pinch and plasma focus devices in ASRL (the AtomicScience Research Laboratory).
  • Jali, Golnabi, Jafari Page 11
    senor is based on a CCD camera and offers the color images from the object under study and also provides quantitative information concerning the image profile. It is possible to obtain reflection and image data by using single or double light sources for object illumination. In order to test the potential of the reported vision for color grading and surface analysis of fruits some of the related results are presented in this report. For this study different objects with typical diameters of 0.5-1.5 mm are placed in front of the white light source beam and the reflectance and the transmission shading images are captured. Using two light sources the reflection and image data for different sample fruits are presented in this study. Theoretical analysis of the image concerning the light source, lighting direction, and surface characteristics are also studied by using the MATLAB simulation potential. In agreement with the simulation results, experimental results show that the reported method is very sensitive to the lighting effects, surface material, shape and color that can be used for color recognition and grading of different objects such as color fruits and vegetables.
  • Yousefi, Thornhill, Sakai, Nishino, Ito, Masugata Page 17
    The origin, shape and dynamics of the ubiquitous barred-spiral galaxy remains an enigma for gravitational theorists who must resort to invisible dark matter to explain their origin and dynamics and an unphysical central black hole to power the jets issuing from active galactic nuclei (AGNs). Based upon the observation of spiral plasma forms in the laboratory, we propose the dense plasma focus (DPF) as a laboratory model of formation of barred-spiral galaxies and an AGN and its jets.
  • Ghahramany, Ghanaatian, Olamaei Page 21
    The Rosenbluth separation method is applied to calculate the longitudinal and transverse cross sections in neutral pion electroproduction for four measured energy and square momentum values where the latest data is available, namely W=1.2-1.5 (GeV) and Q2=1.15-1.01 (GeV/c)2.
  • Alizadeh Eslami, Moradi, Abroomand Azar, Abedini Khorrami, Nasiri Laheghi Page 24
    This work concentrates on the growth of carbon nanowalls (CNWs) using hot filament chemical vapour deposition (HF-CVD) technique on a glass substrate coated with Al nanocatalyst. A combination of CH4/NH3/H2 and C2H2/NH3/H2 renders the growth of carbon nanostructures such as diamond nanocrystals, carbon nanowalls, and carbon nanotubes. Parameters affecting the growth of CNTs such as C2H2 flow ratio, deposition time, and temperature are investigated. Low temperature plasma is applied for deposition of Al nanocatalyst on the glass substrate.Surface morphology of the substrate is observed by atomic force microscopy (AFM). Samples are characterized by scanning electron microscopy and Raman spectroscopy. One of important conclusions in this work is that the growth of diamond nanocrystals and CNTs depend on the hydrocarbon gas species in the fed gas and process parameters,respectively. It is also determined that, an increase of the hydrocarbon gas flow rate from 10 sccm to 20 sccm causes the formation of the CNWs on the substrate.
  • Dorranian, Heydari, Sari, Dadras, Torkamany, Sabbaghzadeh Page 29
    In this work the characteristics of nanosecond laser ablation of bulk Cu is reported. Bulk Cu is irradiated by a Q-switched Nd:YAG laser at 1064 nm wavelength in atmospheric air in single pulse and sweep mode. The temperature of the plasma, formed on Cu surface during the experiment is calculated from the spectroscopy measurement by relative intensity line method. Formation of copper oxide and changes in topology of the target surface are discussed in details using metallographic and SEM images. The hole drilled by laser pulse on the Cu surface is scanned. It is found out that the dept of the hole is independent of temperature and is affected by the laser peak power.
  • Ghorannevis, Kato, Kaneko, Hatakeyama Page 33
    In situ plasma analysis was performed during the single-walled carbon nanotubes (SWNTs) growth from nonmagnetic catalysts with plasma chemical vapor deposition (PCVD). The system based on optical emission spectroscopy (OES) was dedicated for in situ diagnostics of PCVD processes. The SWNTs growth were performed for a various H2 flow rates with 50W of an radio frequency (RF) power. Nonmagnetic metal particles were found to havecatalytic activity for the growth of SWNTs under a specific plasma condition. The plasma analysis revealed that the intensities of Hα and CH radicals remarkably increased and decreased by increasing the H2 flow rate, respectively.Based on the comparison between the growth condition of SWNTs and results of plasma analysis, it was found that the intensity ratio of CH/Hα shows fairly similar tendency to the yield of SWNTs as a function of H2 flow rate, i.e.SWNTs could be grown from nonmagnetic catalysts only when CH/Hα is high. This indicates that the intensity ratio of CH/Hα could be useful to optimize the growth condition of SWNTs with Au catalyst.