• 접착 및 계면
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• 제4권2호
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• pp.1-9
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• 2003

Epoxy-amine liquid prepolymers are extensively applied onto metallic substrates and cured to obtain painted materials or bonded joint structures. Overall performances of such systems depend on the created interphase between the organic layer and the substrate. When epoxy-amine liquid mixtures are applied onto more or less hydrated metallic oxide layer, concomitant amine chemical sorption and hydroxide dissolution appear lending to the chelate formation. As soon as the chelate concentration is higher than the solubility product, these species crystallize as sharp needles. Moreover, intrinsic and thermal residual stresses are developed within painted or bonded systems. When residual stresses are higher than the organic layer/substrate adhesion, buckling, blistering, debonding may occur leading to a catastrophic drop of system performances. Practical adhesion can be evaluated with either ultimate parameters (Fmax or Dmax) or the critical strain energy release rate, using the three point flexure test (ISO 14679-1997). We observe that, for the same system, the ultimate load decreases while residual stresses increase when the liquid/solid time increases. Ultimate loads and residual stresses depend on the metallic surface treatment. For these systems, the critical strain energy release rate which takes into account the residual stress profile and the Young's modulus gradient remains quite constant whatever the metallic surface treatment was. These variations will be discussed and correlate to the formation mechanisms of the interphase.

• 한국염색가공학회지
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• 제3권3호
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• pp.34-43
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• 1991

The dyeing property of milling type acid dyes with various chemical constitution were studied in one bath dyeing of Wool/Nylon blended fabrics and the proper dyeing condition to get solid color by using reserving agent was also examined. The result of the experiments can be summarized as follows; 1) Although the effect of pH on dyeing of wool with a highly hydrophiilic dye is great in the dyeing of wool and nylon, the proper pH of dyeing bath is weakly acidic 5, in which levelling dye can be obtained by increasing the solubility product. 2) Under a constant pH, the dye with fewer numbers of sulfonic acid groups increases the dyeing amount of nylon as the concentration of the dye is increased. Thus the appropriate dye for light color is the one with many numbers of sulfonic acid groups and the proper dye for medium and deep color is of fewer sulfonic acid groups for one-bath dyeing. 3) When the dye concentration is greater than the critical depth, the K/S value of wool and nylon was almost not effected or slightly increased.

• 한국정밀공학회지
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• 제17권9호
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• pp.196-201
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• 2000

There is a great demand for reducing the amount of material used in mass-produced plastics parts for material cost constitutes a large percentage of the total cost of a product up to 75% It may be noted that the price of plastics is directly related to the price of petroleum. Material reduction therefore decreases the amount of oil needed for the manufacture of plastics and thus help conserve this natural resource. Therefore microcellular foaming process(MCPs) was studied for solving this problems alternatively in 1980's at M. I. T. Until now in microcellular plastics processes carbon dioxide gas was mainly used for microcellular foaming Because carbon dioxide has more solubility than any other gases such as nitrogen gas or helium gas. The purpose of the this research is measurement of changing of the microcellular plastics' weight by using nitrogen gas in injection molding an comparing weight reduction of microcellular foamed plastics for using carbon dioxide gas with nitrogen gas.

• Journal of Pharmaceutical Investigation
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• 제12권2호
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• pp.37-44
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• 1982

In order to enhance water solubility, ketoprofen was made as lysine salt, such as acetylsalicylic acid lysine salt, ibuprofen lysine salt and amino acid salt of phenylbutazone. The purpose of this study was to make a comparison between ketoprofen lysine salt in aspects of analgesic, anti-inflammatory, and antipyretic effect. The experimental results were summerized as followings. 1. Ketoprofen lysinate was composed of one molecule of ketoprofen and one molecule of lysine. The product was water soluble and melting point was $92^{\circ}C{\sim}94^{\circ}C$. 2. Ketoprofen lysinate showed about 2 times stronger analgesic effect than that of ketoprofen while no difference in antipyretic effect was observed. 3. $LD_{50}$ of ketoprofen lysinate was higher than that of ketoprofen, suggesting ketoprofen lysinate as safer drug. 4. Blood concentration of ketoprofen lysinate was $156{\mu}g/ml$ while the concentration of ketoprofen was $116{\mu}g/ml$ in 30 min., suggesting long acting as well as high blood concentration.

• 열처리공학회지
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• 제9권1호
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• pp.19-26
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• 1996

Melt-quenching of steels leads to various metallographic effects such as refinement of grain size, extension of the solid solubility of carbon and alloying elements, and is expected to improve the mechanical properties of conventional steels. Furthermore, this technique is a useful method for producing sheet directly from liquid state. And it will lend itself to development as a continuous cast process which offers significant savings in energy and product costs. The purpose of this study is to present the microstructures of melt-quenched austenitic stainless steels. As the results of this study, the morphology of melt-quenched microstructure show that the roll contact area is columnar structure, and the free surface area is dendrite structure. As the line speed increases, the ratio of $d_{colunnar}/d_{total}$ increases from 0.12 to 0.60, but the ribbon thickness decreases from $150{\mu}m$ to $30{\mu}m$.

• 대한화학회지
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• 제7권2호
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• pp.170-173
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• 1963

A tri-thiocyanate molybdenum (Ⅴ) complex containing pyridine has been prepared by one step process; namely, the solvent extraction of molybdenum (Ⅴ)-thiocyanate complex into organic solvents followed by precipitation of the compound by addition of pyridine to the extract. It is concluded that the compound has a definite composition regardless of the various mole ratios of molybdenum to thiocyanate ion employed in the preparation. The use of hydrazine as the reducing agent eliminates the necessity of working under inert atmosphere and of further purification of the product. Molybdenum (Ⅴ)-thiocyanate (1:3) complex can be quantitatively and selectively extracted with slightly polar organic solvents such as ethyl acetate, and the pyridine complex is quantitatively obtained due to the insolubility of the compound in them. The oxidation state of molybdenum in the compound is + 5 and the formula appears to be $MoH_2O_2(NCS)_3Py_2$ from the contents of Mo and NCS in the compound. The solubility of the compound in various has been studied at $25^{\circ}C$.

• 대한화학회지
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• 제64권5호
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• pp.259-266
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• 2020

The main purpose of this study is to examine the different physicochemical properties of spray-dried products. The carrier agents and powders after the spray-drying process were analyzed for encapsulation yield, moisture content, color parameters, total polyphenol content (TPC), antioxidant capacity (AC), bulk density, flowability, wettability, hygroscopicity, water solubility index (WSI), particle size and microstructure. The spray-drying process was carried out with different carrier agents including maltodextrin (MD) and the combination of maltodextrin and gum arabic (MD-GA) with MA/GA ratio of 70/30, dried at the inlet/outlet air temperature of 160 ℃/70 ℃, 4 bar, airflow rate of 70 ㎥·h^-1 and feed flow rate of 750 mL·h^-1. The results showed that the different carrier agents have significant influences on the physicochemical properties of the powder produced by the spray-drying method. In there, while the values of recovery efficiency and flowability of spray-dried products from MD are higher than those of spray-dried products from MD-GA combination, the opposite is true for the values of TPC, AC, bulk density and wettability, whereas hygroscopicity and WSI values are equally represented in both products.

• Nuclear Engineering and Technology
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• 제42권4호
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• pp.434-441
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• 2010

The activation products of aluminum and argon are key radionuclides for operational and environmental radiological safety during the normal operation of open-tank-in-pool type research reactors using aluminum-clad fuels. Their activities measured in the primary coolant and pool surface water of HANARO have been consistent. We estimated their sources from the measured activities and then compared these values with their production rates obtained by a core calculation. For each aluminum activation product, an equivalent aluminum thickness (EAT) in which its production rate is identical to its release rate into the coolant is determined. For the argon activation calculation, the saturated argon concentration in the water at the temperature of the pool surface is assumed. The EATs are 5680, 266 and 1.2 nm, respectively, for Na-24, Mg-27 and Al-28, which are much larger than the flight lengths of the respective recoil nuclides. These values coincide with the water solubility levels and with the half-lives. The EAT for Na-24 is similar to the average oxide layer thickness (OLT) of fuel cladding as well; hence, the majority of them in the oxide layer may be released to the coolant. However, while the average OLT clearly increases with the fuel burn-up during an operation cycle, its effect on the pool-top radiation is not distinguishable. The source of Ar-41 is in good agreement with the calculated reaction rate of Ar-40 dissolved in the coolant.

• Animal Bioscience
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• 제34권11호
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• pp.1859-1869
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• 2021

Objective: The effects of a crude protease extracted from Cordyceps militaris (CM) mushrooms on the postmortem tenderization mechanism and quality improvement in spent hen breast were investigated. Methods: Different percentages of the crude protease extracted from CM mushrooms were introduced to spent hen breast via spray marination, and its effects on tenderness-related indexes and proteolytic enzymes were compared to papain. Results: The results indicated that there was a possible improvement by the protease extracted from CM mushroom through the upregulation of endogenous proteolytic enzymes involved in the calpain system, cathepsin-B, and caspase-3 coupled with its nucleotide-specific impact. However, the effect of the protease extracted from CM mushroom was likely dose-dependent, with significant improvements at a minimum level of 4%. Marination with the protease extracted from CM mushroom at this level led to increased protein solubility and an increased myofibrillar fragmentation index. The sarcoplasmic protein and collagen contents seemed to be less affected by the protease extracted from CM mushroom, indicating that substrate hydrolysis was limited to myofibrillar protein. Furthermore the protease extracted from CM mushroom intensified meat product taste due to increasing the inosinic acid content, a highly effective salt that provides umami taste. Conclusion: The synergistic results of the proteolytic activity and nucleotide-specific effects following treatments suggest that the exogenous protease derived from CM mushroom has the potential for improving the texture of spent hen breast.

• 한국산업융합학회 논문집
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• 제26권3호
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• pp.509-515
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• 2023

This study examind the product quality characteristics and industrial application of arrowroot powder added Yanggaeng before its industrial application. Several preliminary experiments were conducted by applying manufacturing conditions and varying the amount of arrowroot powder(1%, 2%, 3%, 4%) added to produce Yanggaeng recipes that can be sold commercially. The moisture content of the produce Yanggaeng was low due to the manufacturing standards, but it showed a significant increase with an increase in the ratio, which was similar to the results of other studies on Yanggaeng. The solubility, particale size distribution, and pH also showed a significant increasing trend. The hardness of arrowroot powder added Yanggaeng decreased with an increase in the amount of arrowroot powder, while springiness, gumminess, and chewiness increased with the addition of arrowroot powder. In terms of color, arrowroot powder showed a dark color, which was well suited to white bean paste and could also be used with black bean paste without any problem. These results were due to the manufacturing ratio being adjusted to meet commercial sales standards, resulting in a lower amount of water being used, and the characteristics of arrowroot powder being applied as they were.