• Journal of the Korean Ceramic Society
• /
• v.54 no.3
• /
• pp.217-221
• /
• 2017

Improvement studies of existing phosphors are needed for use in light emitting diodes (LEDs). Among the phosphors discovered recently, the SLA ($SrLiAl_3N_4:Eu^{2+}$) is a phosphor that has a narrow width. It is now known as a good red phosphor that meets the industry's needs for warm white (color temperature ranging from 2700 to 4000 K) and high CRI (> 80). However, SLA phosphors are obtained from difficult synthetic methods. All commercially available phosphors should be derived from the general solid state synthesis method. The phosphors produced by difficult synthetic methods will inevitably fall out of price competitiveness and will be scrapped. This study succeeded in synthesizing SLA ($SrLiAl_3N_4:Eu^{2+}$) phosphors by using a general solid phase synthesis method based on the reaction energy obtained from DFT calculations. As a result, we found an optimal solid state synthesis method for SLA phosphors.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09a
• /
• pp.350-351
• /
• 2006

A solid stage sinterizacion model of the WC-Co is applied on this work. These results are compaired with the experimental data obtained for nanometric and micrometric sinter powder in an electric furnace and micrometric in a plasma reactor (using Abnormal Glow Discharge AGD). The correlations obtained allow the prediction of the sintering behavior in AGD for nanometric powder. The activation of the solid state sintering is shown with the decraease of the WC size and the use of AGD

• Mycobiology
• /
• v.36 no.3
• /
• pp.183-189
• /
• 2008

The production of aerial conidia of Lecanicillium lecanii 41185, a highly virulent fungus, by solid-state fermentation was studied for use as a biocontrol agent against aphids. Among several agro-industrial solid media, steamed polished rice was found to produce the highest amount of aerial conidia. The optimal conditions for aerial conidia production were determined to be a 28.5% moisture content in the rice, 25$^{\circ}C$ culture temperature, rice pH of 6.0, 75% ambient relative humidity, 4-dold seeding culture, 0.6% $KNO_3$, and 12 d of culture time. The conidia yield increased from $5.7\times10^9$ conidia/g polished rice to 18.2 $18.2\times10^9$ conidia/g polished rice following application of these optimized conditions.

• Journal of the Korean Electrochemical Society
• /
• v.25 no.3
• /
• pp.105-112
• /
• 2022

For the commercialization of all-solid-state batteries, it is essential to develop a solid electrolyte that can be operable at room temperature, and it is necessary to manufacture all-solid-state batteries by adopting materials with high ionic conductivity. Therefore, in order to increase the ionic conductivity of the existing oxide-based solid, Li₇La₃Zr₂O₁₂ (LLZO) doped with heterogeneous elements was used as a filler material (Al and Nb-LLZO). An electrolyte with garnet-type inorganic filler doped was prepared. The binary metal element and the polymer mixture of poly(ethylene oxide)/poly(propylene carbonate) (PEO/PPC) (1:1) are uniformly manufactured at a ratio of 1:2.4, The electrochemical performance was tested at room temperature and 60 ℃ to verify room temperature operability of the all-solid-state battery. The prepared composite electrolyte shows improved ionic conductivity derived from co-doping of the binary elements, and the PPC helps to improve the ionic conductivity, thereby increasing the capacity of all-solid-state batteries at room temperature as well as 60 ℃. It was confirmed that the capacity retention rate was improved.

• Bulletin of the Korean Chemical Society
• /
• v.28 no.3
• /
• pp.439-442
• /
• 2007

A solid state Hg(Au)/HgO reference electrode was prepared utilizing gold amalgam solid particles. Solid fine powder of the gold amalgam was prepared by chemical reduction of Au(III) with NaBH4 followed by reduction of Hg(II) in the presence of gold fine particles. The solid content in the suspension of the gold amalgam particles and fine mercury oxide particles in DMF containing PVC was precipitated by the addition of a large amount of water to give solid Hg(Au)/HgO/PVC mixture. After drying, the mixture was pressure-molded to a physically stable Hg(Au)/HgO composite reference electrode material. The electrochemical characteristics of the electrode as a reference electrode were very similar to an ordinary Hg/HgO reference electrode. The electrode material can be molded and fabricated in any desired shape and size. The surface can be renewed by a simple polishing process whenever contaminated or deactivated. The applicability of the electrode in the electrochemical detection of carbohydrates after anion exchange separation was evaluated.

• Bulletin of the Korean Chemical Society
• /
• v.17 no.11
• /
• pp.1074-1077
• /
• 1996

• Journal of the Korean Ceramic Society
• /
• v.39 no.1
• /
• pp.1-11
• /
• 2002

A bibliographical review of inorganic lithium ion conductors is presented with a focus on those potential candidates for lithium battery application. A wide variety of inorganic lithium ion conductors, both crystalline ceramics and non-crystalline glasses, are considered.

• Journal of the Korean Ceramic Society
• /
• v.19 no.2
• /
• pp.109-114
• /
• 1982

Fluoro-phlogopite crystals (Mica) were synthesized by two different methods; firstly the crystal was crystallized from the melts, and secondly mica crystalline was obtained from the direct solid state reaction. Addition of $CaF_2$ in the mica batch revealed the lowering the solid state reaction temperature. SEM and XRD were employed to observe mica crystalline flakes and solid solution forms. As a starting raw material Pyrophyllite was used resulting in the formation of mica crystals.

• Journal of the Korean Ceramic Society
• /
• v.47 no.1
• /
• pp.66-70
• /
• 2010

This article presents a brief review of our recent studies on flowerlike nanostructured $CeO_2$ materials. These materials are monodispersed microspheres with peony appearance, open mesoporous structure, large specific surface area and nano-crystalline feature. The applications of this type of novel material to SOFC, ethanol steam reforming and CO oxidation are introduced.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2006.06a
• /
• pp.134-135
• /
• 2006