Korean | English

pISSN : 1225-1429 / eISSN : 2234-5078

2020 KCI Impact Factor : 0.17
Home > Explore Content > All Issues > Article List

2014, Vol.24, No.2

  • 1.

    The current status in the silicon crystal growth technology for solar cells

    A-Young Lee | 이동규 | KIM YOUNG KWAN | 2014, 24(2) | pp.47~53 | number of Cited : 2
    Abstract PDF
    Three kinds of crystalline silicon have been used for the solar cell grade. First of all, single crystalline silicon isthe main subject to enhance the production yield. Most of the efforts are focused on the control of the melt-crystalinterface shape affected by the crystal-crucible rotation rate. The main subject in the multi-crystalline silicon ingot is thecontamination control. Faster Ar gas flow above the melt surface will lower the carbon contamination in the crystal. Andalso, twin boundary electrically inactive is found to be more effective than grain boundary for the improvement of theMCLT. In the case of mono-like silicon material, propagation of the multi-crystalline silicon growing from the inner sidecrucible is the problem lowering the portion of the single crystalline part at the center of the ingot. Crystal growingapparatus giving higher cooling rate at the bottom and lower cooling rate at the side crucible was suggested as theoptimum solution obtaining higher quality of the mono-like silicon ingot. Proper application of the seeds at the bottom ofthe crucible would be one of the solutions.
  • 2.

    A study on the crystalline phases of AlN single crystals grown by PVT method

    Kang, Seung-Min | 2014, 24(2) | pp.54~58 | number of Cited : 3
    Abstract PDF
    AlN (Aluminum Nitride) crystals were grown by a PVT (Physical Vapor Transport) method and were characterizedto phases on the growth temperature. The crystals phase and morphology were analyzed using an optical stereo-microscopeand the optimum temperature for the growing was determined. In this report, the characteristics of the AlN crystals grownat various temperatures were reported.
  • 3.

    Effect of process conditions on crystal structure of Al PEO coating. I. Unipolar pulse and coating time

    KIM BAE YEON | 함재호 | DeukYong Lee and 6other persons | 2014, 24(2) | pp.59~64 | number of Cited : 3
    Abstract PDF
    Crystallographic phases of Plasma electrolytic oxidized Al alloy, A1050, were investigated. The electrolyte ofPEO was Na2Si2O3 and KOH. Unipolar pulse, 2000 μsec with 400 μsec + 420 V impulse, were applied for 2 min, 5 min,15 min, and 30 min. γ-Alumina, as well as α-alumina, was main crystal phase. γ-Alumina was appeared in the beginning,then the amount of α-alumina was increased with time, but the amount of γ-alumina remained constant without anyincreasing. So, it is concluded that plasma gas produce γ-alumina at the first, and then γ-alumina transform α-aluminafinally. During the transformation, high temperature of micro plasma gives transformation energy.
  • 4.

    Effect of process conditions on crystal structure of Al PEO coating. II. Bipolar and electrolyte

    KIM BAE YEON | 함재호 | DeukYong Lee and 6other persons | 2014, 24(2) | pp.65~69 | number of Cited : 2
    Abstract PDF
    Crystallographic phases of Plasma electrolytic oxidized Al alloy, A1100, A5052, A6061, A6063, A7075, wereinvestigated. Two types of electrolyte Na2Si2O3 and Na2P2O7 were also compared. Bipolar pulse, 2000 μsec with 400 μsec +420 V impulse and 300 μsec − impulse were applied for 20 min. α-Alumina, γ-alumina, η-alumina, Al4.95Si1.05O9.52, and(Al0.9Cr0.1)2O3 were mainly observed. Si, component of electrolyte, were moved into the PEO layer by bipolar pulse. Glassyphase was also observed at the surface of Na2Si2O3 electrolyte treated PEO layer, and increased with the Mg content of Alalloy. It is concluded that at first glassy phase was formed by the micro plasma, and the high temperature of plasma turnsglassy phase to several crystalline phases. And we could expect that many other crystalline phase could be formed by PEOprocess.
  • 5.

    The effect of Zn2TiO4 on willemite crystalline glaze

    Lee,Chi-Youn | Lee Hyun Soo | 신경현 | 2014, 24(2) | pp.70~76 | number of Cited : 3
    Abstract PDF
    Zn2TiO4, using an anatase form of TiO2 on zinc crystalline glaze, was shown as effective nuclear agent. Thus theeffects on glaze were studied with synthesized Zn2TiO4 at low temperature. First, the chromophore elements were employedin synthesized Zn2TiO4 then add them in the zinc crystalline glaze. Crystal creation and development of color by Zn2TiO4addition on the zinc crystalline glaze were more effective. Addition of Zn2TiO4, which is developed in low rangetemperature, is effected as zinc crystalline nuclear in the willemite glaze. When 5 wt% of synthesized Zn2TiO4 was addedto the willemite glaze, nuclear creation increases and steadily retains. Therefore addition of respectively doped Zn2TiO4 withCoO, NiO, and CuO would increase doped effects in the glaze, various color willemite crystal were obtained.
  • 6.

    Bloating mechanism for coal ash with iron oxide

    Lee,Ki-Gang | 2014, 24(2) | pp.77~83 | number of Cited : 4
    Abstract PDF
    The purpose of this study was to figure out the impacts of iron oxide types and dosages to bloating whenproducing artificial lightweight aggregates by utilization of recycled resources such as bottom-ash, reject-ash and dredgedsoil. In order to figure out chemical characteristics of raw materials, XRD and XRF analyses were performed. 50 wt% ofdredged-soil, 15 wt% of bottom-ash and 35wt.% of reject-ash were mixed, then the amount of iron oxide was varied at 5to 30 wt% with intervals of 5 wt% with Fe2O3 and Fe3O4 respectively. As molded aggregates were sintered by rapidsintering in intervals of 40oC from 1060oC to 1180oC, specific gravity and water absorption were measured. As a result,the artificial lightweight aggregate with iron oxide of 10~15 vol% showed the lowest specific gravity, and it was identifiedthat the more iron oxide vol% increases, the more specific gravity increases because of liquid phase sintering.
  • 7.

    A simple route for synthesis of SnO2 from copper alloy dross

    Lee, Jung-il | 이보슬 | 이지영 and 3other persons | 2014, 24(2) | pp.84~87 | number of Cited : 2
    Abstract PDF
    Separation/recovery of valuable metals such as zinc, nickel or tin from copper alloy dross has recently attractedfrom the viewpoints of environmental protection and resource recycling. In this study, preliminary investigation onseparation of tin (Sn) from copper alloy dross using selective dissolution method was performed. The tin in the copperalloy dross did not dissolve in an aqueous nitric acid solution which could allow the concentration/separation of tin fromthe copper alloy dross. Precipitation of tin as H2SnO3 (meta stannic acid)occurred in the solution and transformed to tindioxide (SnO2) after drying process. The dried sample was heat-treated at low temperature and its crystal structure, surfacemorphology and chemical composition were investigated.