• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.16 no.2_3
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• pp.59-65
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• 2010

Starch was modified with epichlorohydrin(ECH) to improve the miscibility with LDPE and LLDPE. Native starch or epichlorohydrin treated starch was mixed with grycerol and LDPE/LLDPE resin using a kneader and extruded using a single screw extruder to make pallets. The pallets were compression-molded at 145 into composite boards to evaluate their color, oxygen permeation, mechanical and thermal properties, and degradability under UV irradiation. Sheets with epichlorohydrin treated starch generally showed higher L-value than that of native starch blend sheets. The hunter b-values in both native starch blends and epichlorohydrin treated starch blends increased with Increasing starch contents. Tensile strength and percent elongation of sheets decreased with increasing starch contents. Tensile strength and percent elongation of sheets decreased with increasing starch contents. The degradability of blends under UV radiation increased with increasing starch contents in both blend types. The results represents that crosslinking of starch with epichlorohydrin may be a good method to improve miscibility of starch with petroleum-based materials.

• Journal of The Korean Digital Architecture Interior Association
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• v.12 no.3
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• pp.59-66
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• 2012

Autoclaved Lightweight Concrete(ALC) features such as a high performance insulation, the fire resistance, the advantage of easy handing construction, and lightweight panels applied the curtain wall system. ALC materials are certified as non-toxic environmental and eco-friendly productions. But ALC external panels mixed with blast furnace slag pounder and silica fume have to be coated with a stucco compound or plaster because of resisting the ambient environment. This study is that mixing tests to evaluate a performance analysis of exterior paints to be make-up pigments(organic or inorganic) coated with panel surface. Testing compared by KS F 2476; flow test, KS F 2426; compression strength test, KS F 2762; bond strength test. In results, the case of the inorganic binder, ratio of alumina cement : anhydrite is 90:10 to 80:20 at the highest level of intensity. In the case of the organic binder, adhesive strength rating at surface of ALC, the pullout strength is below 0.5 $N/mm^2$ but the normal concrete is over 2.0$N/mm^2$. A contents ratio of EVA resin is more than 3% and then bond strength is effectively.

• Journal of the Korean Chemical Society
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• v.15 no.2
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• pp.49-54
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• 1971

It is shown that the impurities of Cu(II), Pb(II), Zn(II) and Ag(I) in Bismuth metal and the components of Pb(II), Zn(II) and Sn(IV) in Bismuth alloy are separated into their components from each other by elutions through $3.14cm^2{\times}10cm$ cation exchange resin, $Dowex\;50w\;{\times}\;8$ (100~200 mesh), column with the mixed solutions of HAc and NaAc as the eluents. The elution curve of Fe(III) has a long tailing and is not separated quantitatively from Bi(III). The eluents used for this separation are as follows; 1M HAc + 0.1M NaAc (pH 3.36) for Fe(III) and Bi (III). 0.3M HAc + 0.3M NaAc (pH 4.70) for Cu(II), Pb(II) and Zn(II). 0.5M HAc + 0.5M NaAc (pH4.70) for Ag(I) and Sn(IV). The analysis of cations eluted are carried out by spectrophotometry and EDTA titrimetry. Their recoveries are more than 99%.

• Journal of the Korean Chemical Society
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• v.16 no.6
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• pp.354-360
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• 1972

Formation of the complexes of barium, strontium and calcium ions with dibasic organic acid ions in dilute solution was studied at room temperature, utilizing the equilibrium exchange technique which involved the uses of radioactive alkaline earth metal ions and cation excbange resin. The organic acids used in this study were succinic and tartaric acids, and the solvents used were water, 20 % acetone-water and 20 % ethanol-water. The pH of the solutions was controlled to 7.2∼7.4, and the ionic strength of the solutions was kept at approximately 0.1. The experimental results indicated that the alkaline earths formed one-to-one complexes in solution with the dibasic acids examined, and that the relative stabilities of the complexes increased in the order: $Ba^{++}; succinic

• Journal of the Korean Ceramic Society
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• v.33 no.9
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• pp.1003-1011
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• 1996

Hydroxyapatite powder was synthesized by a citrate method, . Char-like precursor composed of Ca8(HPO4)2(PO4)4.5H2O (OCP) and CaCo3 was found via viscous resin-like intermediate by heating the mixed aqueous solution of Ca(NO3)2.4H2O(NH4)2HPO4 and citric acid. Resulted powder was transformed into hydroxyapatite phase by firing over 120$0^{\circ}C$-135$0^{\circ}C$ for 4 hr using the powder calcined at 90$0^{\circ}C$ for 10 hr composed of mostly single hydroxyapatite phase. The sintered densities increased with firing temperature up to 130$0^{\circ}C$ but the highest relative density was about 94% of theoritical value. indicating the presence of closed pores. The maximum 96 MPa of flexural strength was obtained at 120$0^{\circ}C$ firing but the flexural strength showed lower values over the above sintering condition. Vitro test was performed by immersing of two jointed specimens in SBF for seven days and adhesion was observed between two specimens.

• Journal of the Korean Ceramic Society
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• v.50 no.4
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• pp.280-287
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• 2013

Plate-type phosphor is a promising substitute in overcoming the issues related to the powder phosphor paste mixed with resin. In this research, $Ca-{\alpha}-SiAlON:Eu^{2+}$ plate phosphor ($Ca_xSi_{12-(m+n)}Al_{m+n}O_nN_{16-n}:Eu_y$) was investigated for the varied compositions (m,n) of the host crystal with the fixed Eu content (y). Densification was promoted for the compositions with increasing 'm' values for the m=2n relationship. Dictated by the Eu concentration inside the phosphor crystal, photoluminescence intensity was stronger in ${\alpha}2$ specimen (m = 3.0, n = 1.5) containing the second phases when compared to ${\alpha}1$ specimen (m = 1.5, n = 0.75) comprising a single-phase ${\alpha}$-SiAlON. The concentration of Eu in the non-emitting amorphous interfacial glass phase was 2~4 times of the designed Eu concentration inside the ${\alpha}$-SiAlON crystal.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.05a
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• pp.113-118
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• 2005

Recycle methodology was researched on the HIPS(High Impact Poly Styrene) materials which are used in modern industry widely, For the various mixing ratio between virgin pellets of HIPS and recycled ones, tensile strength and shrinkage ratio were analyzed with injection molding experiments and numerical simulations. In addition, the deviations of dimensional accuracy were observed in accordance with various molding conditions. Molding conditions such as mold and melt temperature were changed by 3 steps. Mixing ratio between virgin pellets of HIPS and recycled ones were under controlled with 15%, 30% and 45%.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2008.04a
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• pp.191-197
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• 2008

In this study, as a fuel filter for automobiles, base paper which can filtrate the polluted particles must satisfy with the standards of each vehicle. and a filter of impregnation paper made that combining the base paper with the resin. Therefore, They were wanted to found out the factors that affect base paper and impregnation paper according to content of HPZ, Mulberry pulp(MP), Laub holze bleached kraft pulp(LBKP). The most important things we wanted to find out in base paper and impregnation paper test were weight, thickness, air permeability, burst and tensile strength, maximum pore size and mean pore size, stiffness. we wanted to measure a rate of change of these condition by adjusting a rate of mixing for HPZ, MP and LBKP. Moreover, It suited for an impregnation paper mixed with a rate of mulberry pulp 20%, HPZ 40% and LBKP 40%. Used resins in this study was Phenol, Acryl, PVAc. And as every resins, sample was divided into existence and nothing of embossing. as a fuel filter for automobiles, It was appeared that the suitable condition of base paper was a rate of mixing for HPZ(40%), MP(20%) and LBKP(40%).

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.12
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• pp.49-55
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• 2020

In order to improve the electromagnetic shielding rate of Carbon Fiber (CF), it was produced using the nickel nano-powder impregnating method. Using two types of nickel powder having thicknesses of 50 ㎛ and 100 ㎛, and a thermoplastic elastomer resin, a compound containing 10-20% nickel content was mixed and then manufactured through an extruder. The CF coated with the compound was woven and manufactured using a 1-ply specimen. The final nickel content of the specimen was verified using TGA and the distribution of nickel powder on the CF surface was verified using SEM. The metal shows a high shielding rate in the low-frequency band, but the shielding rate decreases at higher-frequency bands. The CF improves at the higher frequency band, and metals reflect electromagnetic waves while carbon absorbs electromagnetic waves. The study of shielding materials, which are stronger and lighter than metal, by using CF lighter than metal and enabling the shielding rate from low-frequency band to high-frequency band, confirmed that the larger the area coated with nickel nano-powder, the better the electromagnetic shielding performance. In particular, CF coated with a thickness of 100 ㎛ has a shielding rate similar to that of copper and can also be used for EV/HEV automotive cables and other applications in the future.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1544-1551
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• 2024

A unique brick series based on Vietnamese clay was manufactured at 114.22 MPa pressure rate for γ-ray attenuation purposes, consisting of (x) metallic waste & (90%-x) red clay mineral & 10% (hardener mixed with epoxy resin), where (x) is equal to the values 0%, 20%, 40%, 50%, and 70%. The impacts of industrial metal waste ratio in the structure and radiation protective characteristics were evaluated experimentally. The increase in metallic waste doping concentrations from 0% to 70% was associated with an increase in the manufactured brick's density (ρ) from 2.103 to 2.256 g/cm³ while the fabricated samples' porosity (Φ) decreased from 11.7 to 1.0%, respectively. Together with a rise in fabricated brick's density and a decrease in their porosities, the manufactured bricks' γ-ray attenuation capacities improved. The measured linear attenuation coefficient (μ, cm^-1) was improved by 30.8%, 22.1%, 21.6%, and 19.7%, at E_γ equal to the values respectively 0.662, 1.173, 1.252, and 1.332 MeV, when the metallic waste concentration increased from 0% to 70%, respectively. The study demonstrates that manufactured bricks exhibit superior radiation shielding properties, with radiation protection efficiencies of 88.4%, 90.0%, 91.7%, 92.1%, and 92.4% for bricks with industrial metal waste contents of 0%, 20%, 40%, 50%, and 70%, respectively, at γ-ray energy (E_γ) of 1.332 MeV.