• Journal of the Korean institute of surface engineering
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• v.49 no.4
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• pp.368-375
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• 2016

MoN-Cu thin films were prepared to achieve appropriate properties of high hardness and low friction coefficient, which could be applied to automobile engine parts for reducing energy consumption as well as solving wear problems. Composite thin films of MoN-Cu have been deposited by various processes using multiple targets such as Mo and Cu. However, those deposition with multiple targets revealed demerits such as difficulties in exact control of composition and homogeneous deposition. This study is aiming for suggesting an appropriate process to solve those problems. A single alloying target of Mo-Cu (10 at%) was prepared by powder metallurgy methods of mechanical alloying (MA) and spar plasma sintering (SPS). Thin film of MoN-Cu was then deposited by magnetron sputtering using the single alloying target of Mo-Cu (10 at%). Properties of the resulting MoN-Cu thin film were examined and compared to those of MoN-Cu thin films prepared with double targets of Mo and Cu.

• Korean Journal of Materials Research
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• v.27 no.4
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• pp.179-183
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• 2017

$2ZrO_2{\cdot}P_2O_5$ powder, which is not synthesized by solid reaction method, was successfully synthesized through PVA solution method. In this process, the firing temperature and the PVA content strongly affected the crystallization behavior and final particle size. A stable ${\alpha}$-phase $2ZrO_2{\cdot}P_2O_5$ was synthesized at a firing temperature of $1200^{\circ}C$ and holding time of 4 h. ${\beta}$-phase $2ZrO_2{\cdot}P_2O_5$ was observed, with un-reacted $ZrO_2$ phases, for firing temperatures lower than $1200^{\circ}C$. In terms of the PVA content effect, the powder prepared with a PVA mixing ratio of 12:1 showed stable ${\alpha}$-phase $2ZrO_2{\cdot}P_2O_5$; however, the ${\beta}$-phase was found to co-exist at relatively higher PVA content. The synthesized ${\alpha}$-phase $2ZrO_2{\cdot}P_2O_5$ powder showed an average particle size of 100~250 nm and an average thermal expansion coefficient of $-2.5{\times}10^{-6}/^{\circ}C$ in the range of room temp. ${\sim}800^{\circ}C$.

• Resources Recycling
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• v.23 no.4
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• pp.30-36
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• 2014

300,000 tons of waste tires are annually being produced with development of the automotive industry in Korea. Landfill and incineration treatment system are causing the economic problem through secondary environmental pollution and waste. Therefore, as one of the ways to take advantage of this, Thermo-Plastic Vulcanized (TPV) composite was prepared by the ground waste tire and plastic powders. The waste tire powder was gained by mechanical fracturing through crushers. The waste tire powder was ground by a shear crushing method and a 2-stage disk mill method instead of cutting crushing one. The waste tire powder of 50 mesh was mixed with Polypropylene(PP) in various proportions. TPVs were prepared by an extrusion, and tensile and impact tests were performed. In addition, the same experiments were repeated in 40, 80, 140 mesh conditions in order to observe size effect of waste tire powders.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.3 no.2
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• pp.25-31
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• 1996

Various treaments such heating, acid tenting, acid healing, alkaline treating, acid+alkaline renting were attempted to investigate their effects on molar ratio, chemical composition, DTA and specific surface area(SSA) of natural zeolite poder. Molar ratio, Si to AI. of natural zeolite was 4.78, which represented high silica type. Composition of natural zeolite showed that $SiO_2$ was 66.34% $Al_2O_3$ was 13.89%, $Fe_2O_2$ was 1.55% X-ray diffraction showed that main component of natural zeolite was mordenite and clinoptliolite. Differential Thermal Analysis and Thermogravimetry curve of natural zeolite was showed to peak of endothermic peak at $80^{\circ}C$ and it means to the peak of dehydrate reaction, but recristalization was not formed below at $1,000^{\circ}C$. Weight loss during calcination was 16% at $1,000^{\circ}C$. Thermal treatments on SSA of natural zolite powder decreased from $75.2m^2/g\;to\;2.1m^2/g$. In contrast chemical treatments on SSA showed to increase to $300.2m^2/g$(1 N HCl treating), $54.9m^2/g$(1 N NaOH) and $90.9m^2/g$(HCl+NaOH)tudy, it could be proposed to employ acid tret method as packaging materisls for MA packaging.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.19 no.2
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• pp.87-94
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• 2013

To investigate the effects of functional MA films (FMA) masterbatched by zeolite powder treated with 1 N HCl, 0.5 N NaCl solution and anti-fogging agent (NA) compared with control on the freshness extension of 'Fuji' apples during storage at $15^{\circ}C$. Preference, weight loss, total ascorbic acid, sugar content, acidity, change of gas composition in package were measured. After 150 days of storage, the weight loss of control (L) apples was 1%, that of apple in FMA film (NA) was 1.5% after 150 days. Total ascorbic acid content of apples in control (L) after 150 days was 2.09 mg%, those of apple in FMA film (NA) was 2.72 mg%. The titratable acidity of apple in FMA film was higher than that in control, while soluble solids content of apples in FMA film was lower than that in control after 150 days. Ethylene gas adsorbability in control was 192.2 ppm and those in FMA film was 141.4 ppm after 150 days. Overall, apples in FMA film was better than that of control. It was verified that apples packed with LLDPE film (control) lasted about 130days, while those with FMA films lasted about 170 days. Also, FMA films treated with anti-fogging agent few different compare to nontreated film, but commerdity on the display in market was considered higher than that of non-treated anti-fogging agent.

• Microbiology and Biotechnology Letters
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• v.24 no.3
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• pp.304-310
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• 1996

For a probiotic yoghurt it is desirable to utilize lactic acid bacteria with a high survival rate and beneficial function to human beings. We have examined a variety of lactic acid bacteria to assess the acid and bile tolerance and antibiotic resistance. In addition, an in vitro culture experiment was performed to evaluate their ability to reduce cholesterol levels in the growth medium. Thirteen strains were selected from in vitro cholesterol assays and fed to Sprague-Dawley rats with a high-cholesterol diet. Among the 13 strains tested, 8 strains were shown to reduce serum cholesterol levels significantly after 24 days of administration in vivo. Rats were fed lyophilized yoghurt powder fermented with a combination of 3 selected strains: Bifidobacterium infantis AM-220, Lactobacillus AM-245, and Styeptococcus MA-1. The levels of total cholesterol and low density lipoprotein were significantly lower (p$\leq$0.05) in rats fed the yoghurt powder compared with control group. These studies suggest that yoghurt fermented with appropriately selected lactic acid bacteria may have a anticholesterolemic effect.

• Journal of Powder Materials
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• v.12 no.4 s.51
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• pp.266-272
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• 2005

Transition metal ions($Ni^{2+}$, $Cr^{3+}$ and $V^{5+}$) doped $TiO_2$ nanostructured powders were synthesized by mechanical alloying(MA) to shift the adsorption threshold into the visible light region. The synthesized powders were characterized by XRD, SEM, TEM and BET for structural analysis, UV-Vis and photoluminescence spectrum for the optical study. Also, photocatalytic abilities were evaluated by decomposition of 4-chlorophenol(4CP) under ultraviolet and visible light irradiations. Optical studies showed that the absorption wavelength of transition metal ions doped $TiO_2$ powders moved to visible light range, which was believed to be induced by the energy level change due to the doping. Among the prepared $TiO_2$ powders, $NiO^{2+}$ doped $TiO_2$ powders, showed excellent photooxidative ability in 4CP decomposition.

• Journal of Powder Materials
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• v.18 no.6
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• pp.482-487
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• 2011

Alloy 617, Ni-22Cr-12Co-9Mo base oxide dispersion strengthened alloy was fabricated by using mechanical alloying, hot isostatic pressing and hot rolling. Uniaxial tensile tests were performed at room temperature and at $700^{\circ}C$. Compared with the conventional Alloy 617, ODS alloy showed much higher yield strength and tensile strength, but lower elongation. Fracture surfaces of the tensile tested specimens were investigated in order to find out the mechanism of fracture mode at each test temperature. Grain adjustment during tensile deformation was analyzed by electron backscattered diffraction mapping, inverse pole figures and TEM observation.

• Archives of Pharmacal Research
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• v.29 no.12
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• pp.1096-1101
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• 2006

Armeniacae Semen not only contains amygdalin, but emulsin also, which is an enzyme that hydrolyzes amygdalin. The extraction yield of amygdalin from Armeniacae Semen was low, due to the presence of emulsin, when extracted with water. When Schizandrae Fructus solution was used as the extractant; however, amygdalin was almost completely extracted, regardless of the cutting size, due to the absence of the influence of emulsin. In addition, when the crude powder or small piece forms were used with Schizandrae Fructus solution, on epimerization of the D-amygdalin into neoamygdalin occurred. D-amygdalin and its conversion product, neoamygdalin, were quantitatively analyzed by reverse-phase, high-performance liquid chromatography (HPLC), with an optimized eluent of 10 mM sodium phosphate buffer (pH 2.3), containing 11.5% acetonitrile. The concentration and detector response were linearly correlated over the range 0.05 to 2 mM. The detection limits for both D-amygdalin and neoamygdalin were approximately $5\;{\mu}M$ for the amount injected.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.957-958
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• 2006

Fe doped skutterudite $CoSb_3$ with a nominal composition of $Fe_xCo_{1-x}Sb_{12}(0{\leq}x{\leq}2.5)$ have been synthesized by mechanical alloying (MA) of elemental powders, followed by vacuum hot pressing. Phase transformations during mechanical alloying and vacuum hot pressing were systematically investigated using XRD. Single phase skutterudite was successfully produced by vacuum hot pressing using as-milled powders without subsequent annealing. However, second phase of $FeSb_2$ was found to exist in case of $x\geq2$, suggesting the solubility limit of Fe with Co in this system. Thermoelectric properties as functions of temperature and Fe contents were evaluated for the hot pressed specimens. Fe doping up to x=1.5 with Co in $Fe_xCo_{4-x}Sb_{12}$ appeared to increase thermoelectric figure of merit (ZT) and the maximum ZT was found to be 0.78 at 525K in this study.