• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.1
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• pp.111-117
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• 2010

The purpose of this study was to investigate the effect of garlic(Allium sativum L.) extracts with extraction conditions on antioxidant and anticancer activity. The extracts prepared for garlic by hot temperature extraction (HG), low temperature extraction (LG), UMPM extraction (UG), fermentation (FG) and black garlic hot temperature (BG) method. Content of total polyphenol compound was the BG higher than other extracts. The EDA (electron donating ability) and SOD-like activity was increased in dose-dependent manners, and the activity of BG and UM was significantly higher than LG and FG. We examined cytotoxicity, nitric oxide production of Raw 264.7 cell and inhibition of HT 1080 cell by MTT assay. All extracts does not have any toxic effects in macrophages(Raw 264.7). And UG inhibited the production of nitrite in Raw 264.7 cells activated with LPS. The antitumor effects of LG and UG on HT 1080 cell was indicated a significantly inhibition activity. These results suggested that UG (UMPM extraction of garlic) have activities of antioxidant, anticancer effects.

• Journal of the Korean Society of Clothing and Textiles
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• v.5 no.1
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• pp.15-21
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• 1981

The effect of fatty acid content in oily soil and conditions of washing on the removal of triglyceride have been studied. Cotton lawn was soiled with the four-component soil-tripalmitin, palmitic acid, dodecyl alcohol and dodecane-and washed in constant temperature waterbath shaker. The detergency was estimated by analysis of triglyceride labelled carbon-14 on fabrics before and after washing by means of liquid scintillation counting. It was shown that the detergency of triglyceride washed with the nonionic, nonylphenol poly (10)-ethylene oxide and soap was increased steadily with increasing temperature, whereas with the anionics Na-DBS and SLS, the detergency was rather decreased when the temperature was elevated above $40^{\circ}C$. To investigate the effects of free fatty acid content in soil on the removal of triglyceride, the fabrics were soiled altering palmitic acid content, and then washed. From the results, the detergency of triglyceride was developed with increasing free fatty acid content. With soils containing less than $30\%$ of free fatty acid, of the three detergents tested, the nonionic was by far the most effective soil removal. Soap was intermediate and the synthetic anionic was the poorest. With soil containing $45\%$ of free fatty acid, soap was the most effective soil removal. When NaOH was added to detergent solution. the detergency of triglyceride was improved without regard to detergents. The optimum alkalinity was obtained according to free fatty acid content. And the alkalinity changed to low NaOH concentration with increasing free fatty acid content. From the results mentioned above, it could be concluded that the major removal mechanisms of triglyceride containing oily soil were mesomorphic phase formation, solubilization and soap forma-tion when alkali was added in detergent solution.

• Corrosion Science and Technology
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• v.11 no.6
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• pp.280-285
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• 2012

Aluminum is on active metal, but it is well known that its oxide film plays a role as protective barrier which is comparatively stable in air and neutral aqueous solution. Thus, aluminum alloys have been widely applied in architectural trim, cold & hot-water storage vessels and piping etc., furthermore, the aluminum alloy of AC8A have been widely used in mold casting material of engine piston because of its properties of temperature and wear resistance. In recent years, the oil price is getting higher and higher, thus the using of low quality oil has been significantly increased in engines of ship and vehicle. Therefore it is considered that evaluation of corrosion resistance as well as wear resistance of AC8A material is also important to improve its property and prolong its lifetime. In this study, the effect of solution and tempering heat treatment to corrosion and wear resistance is investigated with electrochemical method and measurement of hardness. The hardness decreased with solution heat treatment compared to mold casting condition, but its value increased with tempering heat treatment and exhibited the highest value of hardness with tempering heat treatment temperature at $190^{\circ}C$ for 24hrs. Furthermore, corrosion resistance increased with decreasing of the hardness, and decreased with increasing of the hardness reversely. As a result, it is suggested that the optimum heat treatment to improve both corrosion and wear resistance is tempering heat treatment temperature at $190^{\circ}C$ for 16hrs.

• Korean Journal of Materials Research
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• v.8 no.12
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• pp.1152-1157
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• 1998

The PZT films were deposited on the Pt/Ti/$SiO_2$/Si substrates using multi- target DC magnetron reactive sputtering. The perovskite single phase with the composition close to the stoichiometric one, was obtained even at high substrate temperature of $540^{\circ}C$ by 2-step method, which is that PZT film was deposited for a short time at low substrate temperature ($480^{\circ}C$) to promote the nucleation of perovskite phase by reducing the volatility of Pb oxide molecules, followed by the deposition at the elevated temperature to suppress the excess incorporation of Pb component in the PZT film. This two-step method, in combination with the RTA treatment, gives rise to good electrical properties of the deposited PZT films: remanent polarifaion,$18\mu$C/$\textrm{cm}^2$; coercive field, 45kV/cm; leakage current of 10$^{-4}$ A/$\textrm{cm}^2$ at high electric field of -500kV/cm.

• Korean Journal of Materials Research
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• v.13 no.4
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• pp.233-238
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• 2003

Ferromagnetic tunnel junctions, Ta/Cu/Ta/NiFe/Cu/$Mn_{75}$ $Ir_{25}$ $Co_{70}$ $Fe_{30}$/Al-oxide, were fabricated by do magnetron sputtering and plasma oxidation process. The effect of annealing temperature on the local transport properties of the ferromagnetic tunnel junctions was studied using contact-mode Atomic Force Microscopy (AFM). The current images reflected the distribution of the barrier height determined by local I-V analysis. The contrast of the current image became more homogeneous and smooth after annealing at $280^{\circ}C$. And the average barrier height $\phi_{ave}$ increased and its standard deviation $\sigma_{\phi}$ X decreased. For the cases of the annealing temperature more than $300^{\circ}C$, the contrast of the current image became large again. And the average barrier height $\phi_{ave}$ decreased and its standard deviation $\sigma_{\phi}$ increased. Also, the current histogram had a long tail in the high current region and became asymmetric. This result means the generation of the leakage current that is resulted from the local generation of a low barrier height region. In order to obtain the high tunnel magnetoresistance(TMR) ratio, the increase of the average barrier height and the decrease of the barrier height fluctuation must be strictly controlled.led.

• Korean Journal of Materials Research
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• v.30 no.11
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• pp.615-620
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• 2020

Oxide semiconductor, represented by a-IGZO, has been commercialized in the market as active layer of TFTs of display backplanes due to its various advantages over a-Si. a-IGZO can be deposited at room temperature by RF magnetron sputtering process; however, additional thermal annealing above 300℃ is required to obtain good semiconducting properties and stability. These temperature are too high for common flexible substrates like PET, PEN, and PI. In this work, effects of microwave annealing time on IGZO thin film and associated thin-film transistors are demonstrated. As the microwave annealing time increases, the electrical properties of a-IGZO TFT improve to a degree similar to that during thermal annealing. Optimal microwave annealed IGZO TFT exhibits mobility, SS, V_th, and V_H of 6.45 ㎠/Vs, 0.17 V/dec, 1.53 V, and 0.47 V, respectively. PBS and NBS stability tests confirm that microwave annealing can effectively improve the interface between the dielectric and the active layer.

• Journal of the Korean Ceramic Society
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• v.20 no.2
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• pp.99-106
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• 1983

This experiment has been carried out for the purpose of investigating the effect of $Ga_2O_3$ and $GeO_2$ additivies on sintering of magnesium oxide over the temperature range of 130$0^{\circ}C$~150$0^{\circ}C$. The effect of calcining temperature on the bulk densities of fired compacts prepared from this material was observed MgO powder has been obtained by calcining extra reagent grade magnesium carbonate(basic fired) at 90$0^{\circ}C$ for 30 minutes $Ga_2O_3$and GeO2 were added in the ratio of 1, 2, and 3 wt% to MgO and mixed with calcined MgO. The specimens were prepared by compression with pressure of $700kg/cm^2$ than fired at 130$0^{\circ}C$~150$0^{\circ}C$ for 0-5hrs. Sintering behaviour and microstructure of the fired specimens were examined. The optimum calcination temperature of magnesium carbonate was 90$0^{\circ}C$. Densification rates obeyed the equation D=K in t+c. Theoretical density in the case of addition of $Ga_2O_3$ was 23.1 kcal/mole in the case of the additive $GeO_2$ was 14.176kcal/mole. This low value would appear to support a machanism of grain boundatry diffusion The range of average grain size in the case of addition of $Ga_2O_3$ and $GeO_2$ was 21$\mu\textrm{m}$-31$\mu\textrm{m}$.

• Applied Biological Chemistry
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• v.35 no.5
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• pp.404-409
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• 1992

Hydroxypropylated starches and acetylated starches were prepared by reaction of potato starch with propylene oxide and acetic anhydride, respectively and then degree of retrogradation and swelling power were investigated in different pHs and temperature. The extent of retrogradation determined by glucoamylase method during freeze-thaw treatment and storage in low temperature $(0{\sim}5^{\circ}C)$ showed that modified potato starches were slowly retrograded as the increase of degree of substitution. The order of the retrogradation tendencies in different pHs were pH 4>pH 6>pH 8>pH 10. Retrogradation of hydroxypropylated potato starches were less than that of acetylated potato starches. Swelling power of starches were influenced more by the temperature than by the pH. The order of the swelling power tendencies in different pHs were pH 10>pH 2>pH 8>pH 4>pH 6.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.379-380
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• 2007

The characteristics of a co-sputtered indium zinc tin oxide (IZTO) films prepared by dual target dc magnetron sputtering from IZO and ITO targets at a room temperature are investigated. Film properties, such as sheet resistance, optical transmittance, surface work function and surface roughness were examined as a function of ITO dc power at constant IZO dc power of 100 W. It was shown that the increase of the ITO dc power during co-sputtering of ITO and IZO target resulted in an increase of sheet resistance of the IZTO films. This can be attributed to high resistivity of ITO film prepared at room temperature. Surface smoothness and roughness were investigated by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The synchrotron x-ray scattering results obtained from IZTO film with different ITO contents showed that introduction of ITO atoms into amorphous IZO film resulted in a crystallization of IZTO film with (222) preferred orientation due to low alc transition temperature of ITO film. However, the transmittance of the IZTO films with thickness of 150 nm is between 80 and 85 % at wavelength of 550 nm regardless of ITO content. Possible mechanism to explain the ITO and IZO co-sputtering effect on properties of IZTO is suggested.

• Journal of the Korean Society for Heat Treatment
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• v.31 no.4
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• pp.171-179
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• 2018

Copper powder dispersed with 4 vol.% of $Cr_2O_3$ was successfully produced by a simple milling at 210 K with a mixture of $Cu_2O$, Cu and Cr elemental powders, followed by Hot Pressing (HP) at 1123 K and 50 MPa for 2h to consolidate the milled powder. The microstructure of the HPed material was characterized by standard metallographic techniques such as XRD (X-ray Diffraction), TEM and STEM-EDS. The results of STEMEDS analysis showed that the HPed materials comprised a mixture of nanocrystalline Cu matrix and $Cr_2O_3$ dispersoid with a homogeneous bimodal size distribution. The mechanical properties of the HPed materials were characterized by micro Vickers hardness test at room temperature. The thermodynamic considerations on the heat of formation, the incubation time to ignite MSR (Mechanically induced Self-sustaining Reaction), and the adiabatic temperature for the heat of displacement reaction between the oxide-metal are made for the delayed formation of $Cr_2O_3$ dispersoid in terms of MSR suppression. The results of TEM observation and hardness test indicated that the relatively large dispersoids in the HPed materials are attributed to the significant coarsening for the high temperature consolidation; this leads to the low Vickers hardness value. Based on the thermodynamic calculation for the operating processes with a limited number of parameters, the formation kinetics and coarsening of the $Cr_2O_3$ dispersoid are discussed.