• Magazine of the Korea Concrete Institute
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• v.8 no.3
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• pp.219-229
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• 1996

Recent construction activity of infrastructures has been booming and accelerating to incur shortage of river sand for concrete works. Thus, sea sand has been excessively used instead of river sa.nd, that directly causes to decrease the quality and the durability of concrete, and then might lead to the collapse of concrete structures. The purpose of this experimental research is not only to develop high-strength concrete using sea sand, but also to investigate mechanical properties of high-strength concrete, such as elastic moduli, compressive strength and etc, which could be used for important design data of concrete structures. Rational analytic formula for elastic moduli have been proposed together with those for the splitting tensile strength and the flexural strength, which are to be predicted from compressive strength of concrete cylinder. Optimum water-cement and water-binder ratio have been experimentally obtained so as to develop high compressive strength with and without using silica fume as a admixture for concrete. It is noted that experimental elastic moduli for high strength concrete above aCk=330kgf /cm2 are less than those by the Code. Appropriate amount of concrete mixture has been experimentally investigated so as to develop maximum compressive, flexural and splitting tensile strength.

• The Korean Journal of Food And Nutrition
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• v.17 no.3
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• pp.278-285
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• 2004

The effects of water, rye flour and vital gluten on the sensory properties of bread were studied by response surface methodology and sensory evaluations. A response surface model was used to evaluate the effects observed and to determine the optimum variations for rye bread. The study included 12 combinations of the following independent variables: Water(57, 62, 67%), Rye flour(0, 10, 30, 50%), and Vital gluten(0, 1, 3, 5%). Bread quality attributes determined were specific volume, color, texture, appearance, taste, chewiness, moisture, overall. Rye bread specific volume, sensory evaluation values and Instrumental testing results were significantly affected by variety (water, rye flour and vital gluten). Rye bread with a high specific volume was produced using water 67%, rye flour 10% and vital gluten 3%. Whereas, rye breads with a high overall sensory evaluation were water 62 %, rye flour 10 % and vital gluten 5%. And Specific volume predicted and overall preference also was shown high. It was shown that the experimental design used provided information about the rye bread of variation of water, rye flour and vital gluten and can be a useful supplement to standardized and optimized formulas in rye bread making. The results suggest that water, rye flour, vital gluten can be combined in rye bread making at various levels, contributing to optimize the functional properties of rye bread. These result represents that breads loaf volume related to directly consumer preference.

• Korean journal of food and cookery science
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• v.14 no.2
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• pp.168-176
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• 1998

The breadmaking characteristics of composite flour containing 30% of buckwheat and 70% of wheat with the addition of vital wheat gluten and water-soluble gums, were studied to establish the optimum formula for the development of buckwheat bread. The addition of vital wheat gluten or/and gums led to successful formation of buckwheat bread, giving loaf volume increase and improvement of sensory quality, especially texture determined by QDA (Quantitative Descriptive Analysis). Among those additives, xanthan gum showed the best volume expansion. Synergistic effects on bread quality were observed when the vital wheat gluten and xanthan gum or guar gum were used together. As buckwheat flour was substituted for wheat flour, gelatinization started early and the maximum viscosity increased measured by an amylography. The addition of gluten and gums caused the initial gelatinization to occur at a higher temperature and maximum viscosity to decrease.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.5
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• pp.736-742
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• 2009

The purpose of this study was to improve the quality of yellow layer cake by adding the Adenophora remotiflora powder. The effects of the Adenophora remotiflora powder in on the final product quality of yellow layer cake and the optimum amount of the Adenophora remotiflora powder in the yellow layer cake formula were investigated. The more increased amounts of Adenophora remotiflora powder was added to the samples, the resulted in "L", and Hunter's "a" and "b" values of the crust color of yellow layer cake were significantly decreased (p<0.05). In the case of crumb color, the more increased levels of Adenophora remotiflora powder led to the samples, the "L" and "a" values were significantly decreased (p<0.05), but "b" value increased significantly (p<0.05). As more Adenophora remotiflora powder was added to the cake samples, the Hardness, Gumminess and Chewiness were significantly increased (p<0.05), but Springiness and Cohesiveness were did not. The results of sensory evaluation showed revealed that the addition of 2% of Adenophora remotiflora powder of overall acceptability were most preferred. Larger scanning electron microscopy revealed the presence of numbers of greater concentrations of cells with different sizes were observed for in samples from products that received 1 % Adenophora remotiflora powder addition. Collapsed cells and cell coalescence with big large and irregular shapes were shown observed in samples that were amended with at 2, 4, and 8% addition Adenophora remotiflora power. The addition of Adenophora remotiflora powder was shown to improved the functionality and quality characteristics such as color, taste and flavor of yellow layer cake. Therefore, it was expected that the 2% addition of Adenophora remotiflora powder will improve the preference to the yellow layer cake.

• Food Science and Preservation
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• v.13 no.2
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• pp.174-179
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• 2006

The objective of the study was to investigate the effect of steaming pressure (0.5, 1.0, and 1.5 bar), steaming time (5, 10, and 15 min), and storage period on Hardness, hardness rate constant and sensory characteristics of Baeksulgi prepared with optimum formula (rice new 100%, water 60%, salt 1.5%, and sugar 15%). Although the hardness was slowly increased during storage period from 0 hr to 8 hr and sharply increased after 12 hr of storage in case of 0.5 bay steam pressure, it was slowly increased after 12 hr storage time in case of steaming pressure at 1.0 ban Hardness rate constant of Baeksulgi was $0.217{\sim}0.184hr^{-1}$ at range of steaming time for $8{\sim}10$ min and pressure at $0.8{\sim}1.0$ bar which was relatively low. Hardness and elasticity of sensory evaluation were increased with the increases in steaming pressure, steaming time, and storage period but cohesiveness was decreased The highest overall preference was steaming pressure at 10 bar, steaming time for 10 min, and storage period for 12 hr. In conclusion, steaming pressure, steaming tim, and storage period influenced Baeksulgi quality such as hardness and sensory characteristics.

• Journal of the Korean Ceramic Society
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• v.50 no.3
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• pp.231-237
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• 2013

Thermodynamic modeling of the $Ni_{0.5}Zn_{0.4}Cu_{0.1}Fe_2O_4$ complex ferrite system has been adopted as a rational approach to establish routes to better synthesis conditions for pure phase $Ni_{0.5}Zn_{0.4}Cu_{0.1}Fe_2O_4$ complex ferrite. Quantitative analysis of the different reaction equilibria involved in the precipitation of $Ni_{0.5}Zn_{0.4}Cu_{0.1}Fe_2O_4$ from aqueous solutions has been used to determine the optimum synthesis conditions. The spinel ferrites, such as magnetite and substitutes for magnetite, with the general formula $MFe_2O_4$, where M= $Fe^{2+}$, $Co^{2+}$, and $Ni^{2+}$ are prepared by coprecipitation of $Fe^{3+}$ and $M^{2+}$ ions with a stoichiometry of $M^{2+}/Fe^{3+}$= 0.5. The average particle size of the as synthesized $Ni_{0.5}Zn_{0.4}Cu_{0.1}Fe_2O_4$, measured by transmission electron microscopy (TEM), is 14.2 nm, with a standard deviation of 3.5 nm the size when calculated using X-ray diffraction (XRD) is 16 nm. When $Ni_{0.5}Zn_{0.4}Cu_{0.1}Fe_2O_4$ ferrite is annealed at elevated temperature, larger grains are formed by the necking and mass transport between the $Ni_{0.5}Zn_{0.4}Cu_{0.1}Fe_2O_4$ ferrite nanoparticles. Thus, the grain sizes of the $Ni_{0.5}Zn_{0.4}Cu_{0.1}Fe_2O_4$ gradually increase as heat treatment temperature increases. Based on the results of Thermogravimetric Analysis (TGA) and Differential Scanning Calorimeter (DSC) analysis, it is found that the hydroxyl groups on the surface of the as synthesized ferrite nanoparticles finally decompose to $Ni_{0.5}Zn_{0.4}Cu_{0.1}Fe_2O_4$ crystal with heat treatment. The results of XRD and TEM confirmed the nanoscale dimensions and spinel structure of the samples.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.2
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• pp.169-175
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• 1992

The Maximum Dry Density (${\gamma}_{dmax}$) and the Optimum Moisture Content (${\omega}_{opt}$) of the soil samples are determined from the compaction curve plotted with the laboratory compaction test results. But in this study three reported tests, and tests on the silty clay and the sandy silt samples are reviewed through the interpolation methods using an equation of the Moisture-Density relations induced from Lagrange's Interpolation Formula without drawing the compaction curves. As the results of the study ${\gamma}_{dmax}$ and ${\omega}_{opt}$, were calculated rapidly and simply using the equation and approached to the results from the compaction curves, and also due to the differences of the ${\gamma}_{dmax}$ and ${\omega}_{opt}$, calculated from the equation between the compaction curves were within $0.01g/cm^3$(0.5%) and 0.4% respectively the method in this study be recommended as a simple method determining ${\gamma}_{dmax}$ and ${\omega}_{opt}$, during the laboratory compaction tests.

• Microbiology and Biotechnology Letters
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• v.41 no.3
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• pp.263-271
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• 2013

A xylanase-producing bacterium was isolated from a soil sample collected in Yongin city, Korea. The strain was aerobic and gram positive, and grew between pH 5.0 and 11.0, forming a yellow-colored colony. The strain was classified as a novel subspecies bacterium of Paenibacillus barcinonensis by 16S rRNA gene sequence similarity, phylogenetic analysis, phenotypic, and biochemical characteristics, and thus named Paenibacillus sp. HX-1. This strain produced extracellular endo-${\beta}$-1,4-xylanase, and the best xylanolytic activity (205.17 unit/ml) was obtained at 96 h in an optimized TNX medium containing 1% (w/v) bacto tryptone, 1% (w/v) NaCl, and 0.7% (w/v) beechwood xylan at pH 7.0, $37^{\circ}C$ and 200 rpm. The endo-${\beta}$-1,4-xylanase produced by the strain HX-1 yielded xylobiose as the end product from beechwood xylan hydrolysis. The enzyme exhibited optimum pH and temperature at pH 7.0 and $45^{\circ}C$, respectively. The remarkable enhancing effect of the TNX medium on xylanase production by HX-1, in spite of its simple formula, may have great advantages for industrial applications of xylanase.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.2
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• pp.196-200
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• 2002

In order to identify the feeding stimulants for flatfish, the feeding tests were conducted using some diets added the amino acids, nucleotides, betaine and TU and acid hydrolysates to basal diet formula, respectively, The feeding stimulant activities and synergistic effects of those compounds were evaluated by a bioassay method. The KH, a kind of acid hydrolysate, possessed a remarkable feeding stimulant activity. It's stimulant activities were increased up to the concentration of $1.05\%$ (w/v), and were independent of pH. The formulation of KH and glycine had a most synergistic effect, The feeding rate of diet with feeding stimulation was 1,4 fold than that of diet without one. The costs for optimum formulation of feeding stimulants were cheaper than some additives in diets. It suggest that the results can practically used in preparation of diet containing feeding stimulant effects for flatfish.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.1
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• pp.53-60
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• 2010

In constructing ILM(Incremental Launching Method) bridges, a launching nose is generally used in order to absorb temporary stress occurring during launching. The sectional forces of superstructure of ILM bridges, which occurs during launching, varies significantly according to the length, weight and stiffness of the launching nose. Thus in order to guarantee the safety of section of ILM bridges, the change of stress according to interaction behavior between launching nose and superstructure should be considered. However, the span division and span length are often decided based on previous cases in practice. It makes the design sections of launching nose are similar in spite of different projects. The designer's anxiety to optimize the launching nose to affect the optimum design of superstructure is also weak. In this study, an design formular to optimize the nose is proposed by using the analysis formular of nose-deck interaction and the design level of ILM bridges constructed on 00 Expressway is examined. According to the result of this study, the proposed design formulas are expected to make a significant contribution to section design that is economically efficient and at the same time guarantees the safety of the superstructure and launching noses of ILM bridges regardless of span length.