• Korean Journal of Materials Research
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• v.9 no.9
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• pp.926-931
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• 1999

The microstructure, wettability, shear strength and aging effect of Sn-3.5Ag/Cu and Alloy42 lead-frame solder joints were measured for comparison. In the case of Sn-3.5Ag/Cu, $Ag_3Sn and Cu_6Sn_5$ phases in the matrix Sn and $1~2\mu\textrm{m}$ thick $Cu_6Sn_5$ phase at the interface of solder/lead-frame were formed. In the case of Sn-3.5Agl Alloy42, only AgJSn phase of low density in the matrix Sn and $0.5~1.5\mu\textrm{m}$ thick $FeSn_2$, phase at the interface of solder/leadframe were formed. Comparing to Cu, Alloy42 showed wider area of spread and smaller contact angle, thus better wet­tability. But shear strength and ductility of Alloy 42 solder joints were only 33% and 75% of those of Cu, respectively After aging at $180^{\circ}C$ for 1 week, $\xi-Cu_3Sn$ layer on $\eta-Cu_6Sn_5$ layer was formed on Cu lead-frame, while coarsened cir­cular $Ag_3Sn$ phase in the matrix and thickened $FeSn_2$, at the interface were formed on Alloy42 lead- frame.

• Korean Journal of Food Science and Technology
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• v.46 no.6
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• pp.702-709
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• 2014

Normal alcoholic fermentation took place at $20-25^{\circ}C$ in yakju (traditional Korean rice wine) prepared without the addition of protease (non-addition group). The total concentration of organic acids increased by 1.0-2.7 fold in the non-addition group. While the concentration of lactic acid and acetic acid increased, the pyroglutamic acid concentration decreased by 51.1 fold. Consequently, the total acidity and volatile acid concentration increased, and the overall pH decreased. Compared to the addition group, the non-addition group showed a 3.0-5.2 fold increase in the amount of amino acids; however, the total estimated concentrations of free-form amino acids were 5.2-11.9 times lower than those in the latter group. The major amino acids found in the non-addition group were alanine, arginine, leucine, and phenylalanine. The yakju preparation from the non-addition group showed a 1.2-3.0 fold decrease in the final color intensity as compared to that from the addition group.

• Korean Journal of Materials Research
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• v.10 no.12
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• pp.799-806
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• 2000

Cu$_{6}$Sn$_{5}$-dispersed 63Sn-37Pb solder bumps of 760$\mu\textrm{m}$ size were fabricated on Au(0.5$\mu\textrm{m}$)/Ni(5$\mu\textrm{m}$)/Cu(27$\pm$20$\mu\textrm{m}$) BGA substrates by screen printing process, and their shear strength were characterized with variations of dwell time at reflow peak temperature and aging time at 15$0^{\circ}C$ . With dwell time of 30 seconds at reflow peak temperature, the solder bumps with Cu$_{6}$Sn$_{5}$ dispersion exhibited higher shear strength than the value of the 63Sn-37Pb solder bump. With increasing the dwell time longer than 60 seconds, however the shear strength of the Cu$_{6}$Sn$_{5}$-dispersed solder bumps became lower than that the 63Sn-37Pb solder bumps. The failure surface of the solder bumps could be divided into two legions of slow crack propagation and critical crack propagation. The shear strength of the solder bumps was inversely proportional to the slow crack propagation length, regardless of the dwell time at peak temperature, aging time at 150 $^{\circ}C$ and the volume fraction of Cu$_{6}$Sn$_{5}$ dispersion.> 5/ dispersion.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.4
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• pp.313-319
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• 2015

This study relates to an investigation into semi-dry manufacturing process of BP sludge based on non-heating production method. In this study, we conducted a research into reduction of water content ratio which arose from mixture of BP by-products of high water content ratio(50% or higher) with industrial by-products to use such BP by-products as construction materials in large quantity. We measured the reduction rate of water content ratio at the feeding ratio of water content reduction agent(1:0.5) in BP by-products. The results showed that water content ratio was the lowest with 18.5% in the mixture of PA+CFA(1:0.5). Moreover, water content ratio ranged between approximately 9.2% and 11.4% at the age of 1 day to 2 days at the aging temperature of $20-30^{\circ}C$, suggesting that the water content ratio was in the range within 10% which was a level suitable for use as construction material in this study. Meanwhile, we compared and evaluated the physical properties of non-heated BP by-products based on post-aging pulverization method. The results showed that there was no significant difference, depending on pulverization method. When production efficiency and economic feasibility were taken into consideration, it was found desirable to use fine particle pulverizer or pin mill enabling continuous production.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.1
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• pp.86-92
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• 2014

Cordycepin is the major functional component of Cordyceps species and is widely used in traditional oriental medicine. Cordycepin has been shown to possess many pharmacological properties, such as enhancement of immune function along with anti-inflammatory, antioxidant, anti-aging, and anti-cancer effects. Here, we investigated the inhibitory effects of cordycepin on cell migration and invasion, which are two critical cellular processes that are often deregulated during metastasis, using HCT116 human colorectal carcinoma cells. According to our data, cordycepin at non-cytotoxic concentrations markedly inhibited the motility and invasiveness of HCT116 cells in a time-dependent manner. RT-PCR and Western blotting results indicated that cordycepin reduced the levels of claudin proteins, which are major components of tight junctions (TJs), and induced tightening of TJs. Cordycepin also attenuated the expression and activities of matrix metalloproteinases (MMPs)-2 and -9, whereas levels of tissue inhibitor of metalloproteinases (TIMPs)-1 and -2 were simultaneously elevated. These findings suggest that cordycepin reduces the migration and invasion of HCT116 cells by modulating the activities of TJs and MMPs.

• Journal of the Korean Ceramic Society
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• v.38 no.11
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• pp.1008-1014
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• 2001

Nanosize YIG powders added by Cerium which is exellent element in magneto-optical effect were synthesized by Sol-Gel method using Ethylene Glycol solvent. In 120 to 150 minute reaction time, stable sol solution which showed no change in viscosity, pH, and aging time was obtained. Monolithic YIG was synthesized at 80$0^{\circ}C$ with DTA and XRD measurement and its lattice parameter had a tendency to increase from 12.3921 $\AA$. Increasing annealing temperature from 80$0^{\circ}C$ to 105$0^{\circ}C$, average particle size was in the range of 40 nm to 330 nm. Saturation magnetization (M$_{s}$) value was increased from 18.37 to 21.25 emu/g due to enhancement of YIG crystallity and decreasing of orthoferrite phase. On the other hand, coercivity (H$_{c}$) value increased up to 90$0^{\circ}C$ and then decreased above 90$0^{\circ}C$. With increasing Ce addition, coercivity was almost not changed but saturation magnetization value was maximum at Ce 0.1 mol% and then decreased because of increasing a orthoferrite amount. Also, curie temperature (T$_{c}$) of YIG were not changed with Ce addition.ion.

• Journal of Life Science
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• v.17 no.10
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• pp.1347-1353
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• 2007

The changes of glycoconjuagates (GCs) in rat kidney due to maturation were studied from samples of fetal and postnatal kidneys by lectin histochemistry. Rat kidneys of perinatal ages and adults were fixed in 4% paraformaldehyde and were stained with nine kinds of biotinylated lectins. The immature forms of the renal developmental stage such as vesicles and ureteric bud were observed in the cortex as late as day 14 of postnatal life, but the histological appearance of the weaning kidney was similar to that observed in adults. As for histochemical properties of GCs in the glomeruli, Con A affinity tended to increase with aging, but both RCA-1 and LCA affinities showed a transient increase in immature glomeruli of neonatal rats. DBA affinity with SBA, PNA, BSL-1 and RCA-1, additional Con A one in proximal tubule, were increased in both proximal and distal tubules according to maturation. In contrast to this, transient intensive LCA affinity were demonstrated in immature proximal and distal tubule of neonatal rats. In the collecting tubules, DBA, SBA, PNA and sWGA affinities tended to increase according to maturation, but transient increase for BSL-1, RCA-1 and LCA affinities were detected in neonatal rats. The present results suggest that the mature glycosylation pattern of the kidney undergoes profound changes during maturation and is probably associated with functional maturation of the kidney.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.1
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• pp.79-87
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• 2010

Ultraviolet is the one of the main environmental factors promoting aging process via increased intracellular generation of reactive oxygen species (ROS) and decreased expression of endogenous antioxidant enzymes and molecules. Therefore, in this study, we tried to search for natural skin-protective antioxidant materials from marine origins (Porphyra Thalli, Laminariae japonicae thallus, Ostreae Concha, Sargassum Thallus, Undaria thallus, Haliotidis Concha, Codium thalli, Syngnathoides biaculeatus, Hippocampus, Stichopus Stichopus, Thalli, Hizikia fusiforme thalli) which exhibit free radical scavenging activity and protect against UVB-induced cytotoxicity and oxidative cell death. Free radical scavenging activity was shown in order of Undaria thallus. Sargassum Thallus, Laminariae japonicae thallus, Hippocampus, Haliotidis Concha, Ostreae Concha, Syngnathoides biacuJeatus. In another experiment, UVB-induced cytotoxicity and cell death were effectively suppressed by treatment of Sargassum Thallus, Haliotidis Concha, Codium thalli, or Hippocampus water extract. Furthermore, UVB-induced cell death was mediated by intracellular accumulation or ROS, which was significantly inhibited by treatment with aforementioned extracts. The protective effect of these marine natural products seemed to be mediated by increased expression of antioxidant enzymes such as catalase, superoxide dismutase, and heme oxygenase-1. These results suggest that Sargassum Thallus, Haliotidis Concha, Codium thalli, and Hippocampus may have preventive and protective potentials as new functional cosmetics against oxidative stress-mediated skin damages and aging with antioxidant properties.

• Journal of Convergence for Information Technology
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• v.11 no.12
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• pp.236-243
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• 2021

The aim of this study was to evaluate the anti-oxidant and anti-wrinkle effect of the black carrot(BC) extracted by supercritical dioxide(SC-CO₂). DPPH/ABTS radical scavenging and total polyphenol contents were measured to investigate the anti-oxidant activity of the BC supercritical extract. Collagen production and MMP-1 expression were assessed in normal human dermal fibroblasts(NHDF) for anti-wrinkle activity, The black carrot extract showed the highest total phenolic content(9.037±1.123 mg GAE/g extract) and the best antioxidant properties as shown by DPPH and ABTS assay. The supercritical fluid extracts of black carrot exhibited low toxicity to NHDF cells. In addition, the supercritical fluid extracts showed MMP-1 inhibition and type I pro-collagen synthesis inducing activities in a dose-dependent manner, respectively. Therefore, these results suggest that the black carrot is a potential source of high anti-oxidative, solvent-free and anti-aging material with promising applications in cosmetic, food, and beauty-food industries.

• Korean Journal of Metals and Materials
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• v.47 no.3
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• pp.147-154
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• 2009

The effect of carbon addition on the microstructures and mechanical properties of $Ni_3Al$ and TiAl intermetallic alloys have been characterized. It is shown that carbon is not only an efficient solid solution strengthener in $Ni_3Al$ and TiAl, it is also an efficient precipitation strengthener by fine dispersion of carbide. Transmission electron microscope investigation has been performed on the particle-dislocation interactions in $Ni_3Al$ and TiAl intermetallics containing various types of fine precipitates. In an $L1_2$-ordered $Ni_3Al$ alloy with 4 mol.% of chromium and 0.2~3.0 mol.% of carbon, fine octahedral precipitates of $M_{23}C_6$ type carbide, which has the cube-cube orientation relationship with the matrix, appear during aging. Typical Orowan loops are formed in $Ni_3Al$ containing fine dispersions of $M_{23}C_6$ particles. In the L10-ordered TiAl containing 0.1~2.0 mol.% carbon, TEM observations revealed that needle-like precipitates, which lie only in one direction parallel to the [001] axis of the $L1_0$ matrix, appear in the matrix and preferentially at dislocations. Selected area electron diffraction (SAED) patterns analyses have shown that the needle-shaped precipitate is $Ti_3AlC$ of perovskite type. The orientation relationship between the $Ti_3AlC$ and the $L1_0$ matrix is found to be $(001)_{Ti3AlC}//(001)_{L10\;matrix}$ and $[010]_{Ti3AlC}//[010]_{L10\;matrix}$. By aging at higher temperatures or for longer period at 1073 K, plate-like precipitates of $Ti_2AlC$ with a hexagonal structure are formed on the {111} planes of the $L1_0$ matrix. The orientation relationship between the $(0001)_{Ti2AlC}//(111)_{L10\;matrix}$ is and $[1120]_{Ti2AlC}//[101]_{L10\;matrix}$. High temperature strength of TiAl increases appreciably by the precipitation of fine carbide. Dislocations bypass the carbide needles at further higher temperatures.