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pISSN : 1225-1429 / eISSN : 2234-5078

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2005, Vol.15, No.4

  • 1.

    Magnetic field effects of silicon melt motion in czochralski crystal puller

    Lee,Jae-Hee | 2005, 15(4) | pp.129~134 | number of Cited : 0
    Abstract PDF
    A numerical analysis was performed on magnetic field effects of silicon melt motion in Czochralski crystalpuller. The turbulent modeling was used to simulate the transport phenomena in 8" single crystal growing proces. Forsmall crucible angular velocity, the natural convection is dominant. As the crucible angular velocity increase, the forcedthe natural and forced convection near the crucible and the temperature profiles of the silicon fluids is similar to the caseof conduction.Key words Magnetic field effects, Czochralski crystal puller, Transport phenomena, Single crystal growing process,Natural convection, Forced convection, Temperature profiles, Silicon fluids, Conduction
  • 2.

    Susceptor design by numerical analysis in horizontal CVD reactor

    이정훈 | 류진복 | 배소익 | 2005, 15(4) | pp.135~140 | number of Cited : 3
    Abstract PDF
    Thermal-fluid analysis was performed to understand the thermal behavior in the horizontal CVD reactor, thereby, to design a susceptor which has a uniform deposition rate during silicon EPI growing. Four different types of susceptor designs, standard (no hole susceptor), hole #1 (240mm), hole #2 (150mm) and hole #3 (60mm), were simulated by CFD (Computational Fluid Dynamics) tool. Temperature, gas flow, deposition rate and growth rate were calculated and analyzed. The degree of flatness of EPI wafer loaded on the susceptor was computed in terms of silicon growth rate. The simulation results show that the temperature and thermal distribution in the wafer are greatly dependent on inner diameter of hole susceptor and demonstrate that the introduction of hole in the susceptor can degrade wafer flatness. Maximum temperature difference appeared around holes. As the diameter of the hole decreases, flatness of the wafer becomes poor. Among the threes types of susceptors with the hole, optimal design which resulted a good uniform flatness (5%) was obtained when using hole #1.
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  • 4.

    Color enhancement and characteristics of natural rubies originated in Africa by the hydrothermaltreatment method

    박춘원 | 2005, 15(4) | pp.145~151 | number of Cited : 0
    Abstract PDF
    Color enhancement of African rubies with dark red was caried out by the heat treatment and the hydrothermaltreatment method respectively. The heat treatment method brought about an adverse effect causing the color to bedeteriorated. However, the hydrothermal treatment method enhanced its color and clarity. The hydrothermal treatmentconditions for color enhancement of them were as follows: solvent: 0.9 M Na2CO3-1 M K2CO3, temperature: 450oC,duration: 48 hrs, filling: 30 %, presure: 375 atm. As the results of characteristics for African rubies obtained under theseconditions, it was known that the amount of Cr3+, Fe3+, Ti4+ was reduced after the hydrothermal treatment from the ICP/MSand XRF analyses. Also, it was found that the red color from the colorimeter analyses was getting lighter. These resultswere consistent with the PL analysis showing that the intensity of the luminescence peak generated by the electrontransition of Cr3+Key words African ruby, Color enhancement, Aggregation, Hydrothermal treatment method, Heat treatment method
  • 5.

    Multi-scale simulation of drying process for porous materials using molecular dynamics(part 2: material properties)

    백성민 | Young Tag Keum | 2005, 15(4) | pp.152~167 | number of Cited : 0
    Abstract PDF
    As the properties of porous materials during the drying process relate to the atomistic defects of heterogeneous materials such as dislocation, grain, grain boundary, pore, etc., the knowledge of nano-scale analysis is needed in order to accurately analyze the drying process for porous materials. In this study, the atomic behavior of porous materials is statically predicted by using the molecular dynamics simulation and the nano-scale material properties are computed. The elastic modulus, thermal expansion coefficient, and volumetric heat capacity numerically found from the molecular dynamics simulation are compared with those of experiment and theory and proved the accuracy.
  • 6.

    Multi-scale simulation of drying process for porous materials using molecular dynamics(part 3: multi-scale simulation)

    백성민 | Young Tag Keum | 2005, 15(4) | pp.152~167 | number of Cited : 0
    Abstract PDF
    In this study, the numerical simulation of drying processes for porous materials is performed by employing the hierarchical multi-scale modeling and the nano-scale material properties obtained from the molecular dynamics simulation. The multi-scale simulation system is set up using pre- and post-processors and the drying process of electric porous ceramic insulator is simulated. The temperature, moisture, residual stress, and displacement distributions are compared with those based on homogenized properties.
  • 7.

    The cultivation and characterization of akoya pearls

    박라영 | KIM PAN CHAE | 2005, 15(4) | pp.152~156 | number of Cited : 2
    Abstract PDF
    The cultivation of akoya pearls was caried out with bio bead nucleus prepared using the hydroxyapatite. Theakoya pearls cultured with bio bead nucleus were shown the color of cream. The luster and orient efect created by anaction of the light from nacre were magnificent. The result of XRD is found that the nacre is a calcium carbonate ofproperties of akoya pearls cultured with bio bead nucleus are same those of akoya pearl cultivated with bead nucleus madefrom washboard shell. Because of the bio bead nucleus developed in this study has such a high capacity in producingvarious sizes and shapes, it is very advantageous for the cultivation of akoya pearls
  • 8.

    Complex dielectric function of CdTe/GaAs thin films studied by spectroscopic ellipsometry

    진광수 | Park, Hyo-Yeol | 조재혁 | 2005, 15(4) | pp.157~161 | number of Cited : 0
    Abstract PDF
    Spectroscopic ellipsomerty measurements of the complex dielectric function of the CdTe thin films grown on GaAs(100) substrates by hot wall epitaxy have been performed in 1.5~5.5eV photon energy range at room temperature. The spectroscopic ellipsometer spectra revealed distinct structures at energies of the E1, E1 + D1, and E2 critical points. These energies were decreased with increasing thickness of CdTe thin films.