• Bulletin of the Korean Chemical Society
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• v.22 no.8
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• pp.793-794
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• 2001

• Journal of Digital Convergence
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• v.15 no.11
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• pp.199-207
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• 2017

The business environment changing very fast with technology advance and convergence makes the role of R&D become more and more important to firms' success. By analyzing the 683 firm-level data of small and medium venture firms with the ordinary least squares regression, this study sheds new light on the following four points. First, small and medium venture firms' exterior R&D collaboration network heterogeneity positively impacts their import substitution from technology development. Second, the existence of the corporate R&D center moderates the positive impact of small and venture firms' exterior R&D collaboration network heterogeneity on their import substitution from technology development. Third, small and venture firms' exterior R&D information network heterogeneity positively impacts their import substitution from technology development. Fourth, The existence of the corporate R&D center moderates the positive influence of small and venture firms' exterior R&D information network heterogeneity on their import substitution from technology development.

• Journal of Families and Better Life
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• v.5 no.2
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• pp.45-64
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• 1987

In this study the phenomenon of commodity substitution of housework is approach in the contexts of economic system, patriachal family system and housework-related human resources. the objectives of this study are as follows: (1) To measure the level of commodity substitution of housework in large cities. (2)To investigate the factors influencing commodity substitution of housework. The samples were composed of 982 housewives dwelling in 6 large cities including Seoul. The statistics used for data analysis were frequency distribution, percetile. multiple regression analysis. The major findings are the following; (1) When the housework was divided into two subdomains , in the domain of food the purchase level was for below average while in the domain of clothes, the level was quite higher than average. This result hows that commodity substitution has become more common in the domain of clothes by mass production of clothes on a commercial scale. (2) the level of commodity substitution of housework was influenced by the family attribute variables such as housewife's age, family income. housewife's education, family types, housewife's brought-up regions, presence of sewing machine, employment status of housewife, by one patriarchal norm variable such as home-orientedness, and by tow human resource variables such as importance of housework and household tasks performance competnecy. Among variables house wife's age was the most influential one and such variables as family income, housewife's education, household task performance competency, importance of housework, and home-orientedness were also important. Considering that the influence of home-orientedness demonstrates the importance of patriarchy and that importance of housework and that performance competency also are determined by the patriarchal variables such as sex-role attitude and home-orientedness, we can conclude that Hartmann's theoretical approach with which the changes of housework were explained in the two contexts of economic system and family system is applied to the changes of housework in Korea.

• Korean Journal of Materials Research
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• v.26 no.4
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• pp.200-206
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• 2016

This study was carried out to investigate the effect of W substitution on the precipitation behavior of ${\chi}$ and ${\sigma}$ phases in super duplex stainless steel. The ${\chi}$ phase was precipitated at the interface of ferrite / austenite phases and inside the ferrite phase at the initial stage of aging. With an increase in the aging time, the volume fraction of the ${\chi}$ phase increased, and then decreased with the transformation from the ${\chi}$ phase to the ${\sigma}$ phase. The ${\sigma}$ phase was precipitated later than the ${\chi}$ phase, and the volume fraction of x phase increased with the increase in the aging time. The ferrite phase was decomposed into the new austenite (${\gamma}2$) and ${\sigma}$ phases by aging treatment. The decomposition of the ferrite phase into the ${\gamma}2$ and ${\sigma}$ phases was retarded by W substitution for Mo. The volume fraction of the ${\chi}$ phase increased and that of the ${\sigma}$ phase decreased due to W substitution. The ${\chi}$ and ${\sigma}$ phases were intermetallic compounds, which had lower nickel concentration, and higher chromium, molybdenum, and tungsten concentrations. The ${\chi}$ phase has higher molybdenum and tungsten concentrations than those of the ${\sigma}$ phase. The amounts of chromium and nickel in the ${\chi}$ and ${\sigma}$ phases did not change, but these phases have higher concentrations of molybdenum and tungsten due to W substitution for Mo.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.3
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• pp.204-209
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• 2003

Utilization of soluble protein recovered from surimi wastewater using calcium powder of cuttle bone were examined. The crude ash content of the heat-induced surimi gel was increased linearly by increasing substitution ratio of recovered protein-ATC toward commercial surimi. Moisture (approximately $76\%$) and lipid $(0.2\%)$ contents were not change, but their protein contents were decreased 15.7 to $14.3\%$ depend on increasing of substitution ratio. The white index of the heat-induced surimi gel by color meter was increased up to $10\%$ of substitution ratio. There were no difference between $0\%\;and\;5\%$ substituted surimi gel in the gel strength. The sensory score on white index and texture of the heat-induced surimi gel did not change in 0 to $10\%$ as a substitution ratio of recovered protein-ATC toward commercial surimi, while decreased in more $15\%.$ The optimal substitution ratio of recovered protein-ATC as a bulking agent was $10\%.$ The heat-induced surimi gel prepared with $10\%$ substitution of recovered protein-ATC was similar to the content and composition of total amino. acids, and superior to calcium content and the ratio of calcium and phosphorus toward those of commercial surimi.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.1
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• pp.35-39
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• 2006

In this study, in order to develop the multilayer piezoelectric actuator and ultrasonic resonator, PMN-PNN-PZT ceramics were fabricated by sintering with $Li_2CO_3-Na_2CO_3$ as sintering aids at $950^{\circ}C$ and their piezoelectric and dielectric characteristics were investigated as a function of PNN substitution. With increasing PNN substitution, dielectric constant(${\epsilon}_r$), electromechanical coupling factor(kp), and piezoelectric d constant($d_{33}$) were increased to $12 mol\%$ PNN substitution and then showed a tendency to decrease rapidly With increasing PNN substitution, crystal structure changed from tetragonal to rhombohedral at $12 mol\%$ PNN substitution and then secondary phase was appeared and its intensity was increased. At the $12 mol\%$ PNN substituted PMN-PZT composition ceramic sintered at $950^{\circ}C$, density, kp, $d_{33}$ and Qm showed the optimum value of $7.79 g/cm^3$, 0.599, 419 pC/N, and 894, respectively for multilayer piezoelectric actuator application.

• Membrane Journal
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• v.27 no.2
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• pp.138-146
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• 2017

The new types of phenoxy-carboxylatophenoxy cosubstituted polyphosphazene were synthesized with various substitution rates. Diabetic diagnostic membranes were prepapared with these types of polyphosphazenes and final absorbances at 680 nm through these membranes were measured at various concentrations of glucose in blood. Basically, the end-point results of varying absorbance values according to time (K/S) had a linear relationship to the glucose concentration. The effects of substitution rates with hydrophilic carboxylatophenoxy groups and hydrophobic phenoxy groups on the glucose concentration measurements were examined. It was very difficult to measure glucose concentration in less than 10% of the hydrophilic substitution rates, because the glucose penetration rate was too slow. But dose-response slope (DRS) values between glucose concentration and K/S values increased as the hydrophilic substitution rates increased in more than 10% of the hydrophilic substitution rates. However, in more than 30% of the hydrophilic substitution rates, DRS value was too rapidly increased, because glucose penetration rate was too fast.

• Korean Journal of Materials Research
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• v.20 no.2
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• pp.55-59
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• 2010

$Na^+$ ion conductivity can be improved by the substitution of an Mg atom for an Al atom to form a nonstoichiometric $Na^+$ $\beta$-alumina. We performed a first principles study to investigate the most stable substitution site of an Mg atom and the resulting structural change of the nonstoichiometric $Na^+$ $\beta$-alumina. Al atoms were classified as four different layers in the spinel block that are separated by conduction planes in the nonstoichiometric $Na^+$ $\beta$-alumina. The substitution of an Mg atom for an Al atom at a tetragonal site was more favorable than that at an octahedral site. The substitution in the spinel block was more favorable than that close to the conduction plane. This result was well explained by the volume changes of the polyhedrons, by the standard deviation of the Mg-O distance, and by the comparison with bulk MgO structure. Our result indicates that the most preferable site for the Mg atom was the tetrahedral site at the spinel block in the nonstoichiometric $Na^+$ $\beta$-alumina.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.10a
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• pp.304-316
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• 2004

When new services are introduced, one of the drivers for market performance of them is the interactions among existing and new services. They are characterized by the substitution or complementary effects among existing and new service or the cannibalization of existing services by new services. This paper analyzes these issues in the telecommunications service industry context. To analyze them, a simple graphical tool or State Transition Diagram(STD) is developed and used. The diagram helps to clearly represent and explain the substitution, complement and cannibalization impact. Then, using the face-to-face survey of 1,200 people, a new wireless internet access service or WiBro is analyzed to identify the substitution/complement and cannibalization impacts in relation with the other competing services. Additionally, the important factors explaining customer subscription and substitution behavior are identified. The analysis results indicate that males, students or on-line game users are more likely to subscribe WiBro. Also, among the potential WiBro subscribers, customers who are less satisfied with the existing fixed line broadband internet access services are more likely to stop subscribing the fixed line service, which implies substitution by a new service. Additionally, this raises the issue of cannibalization if the existing and new services are provided by the same company. In fact we find the cannibalization effect is more serious for the cost sensitive group. We believe that our tool, approach, analysis results and their implications would be very helpful to devise a winning strategy for the new services in the highly uncertain telecommunications business environment.

• Environmental and Resource Economics Review
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• v.12 no.3
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• pp.427-452
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• 2003

Demand analyses often assume perfect substitution and some level of aggregation before analysis and data collection. Earlier works on this subject are carried out in the context of ordinary demand systems. However, perfect substitution is a degenerate special case in the systems and it is much more easily handled in a system of marginal value functions and no previous analysis has used the marginal value functions to test for perfect substitution and make possible aggregation with prior restrictions. In this article, we present the empirical results on a system of marginal value functions in fisheries and pose testable results of perfect substitution and aggregation. The contribution of this article is new establishment of a set of restrictions implying perfect substitutability among all commodities and the application to the problem of commodity aggregate. A system of marginal value functions is estimated in fisheries and its implication of perfect substitution is reasonably drawn.