• Nuclear Engineering and Technology
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• 제53권6호
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• pp.1731-1735
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• 2021

The operation of the nuclear reactor requires accurate and fast methods and techniques for analysing its kinetics. These techniques become even more important when the MOX-fuel is used due to the lower value of delayed neutron fraction 𝛽 for ²³⁹Pu. Based on a Birth-and-Death process review, the mathematical model of thermal reactor core has been proposed different from existing ones. The analytical method for thermal point-reactor parameters evaluation is described within this work. The proposed method is applied for analysis of the unsteady transient processes taking place in a thermal reactor at its start-up or shutdown power change, as well as during small accidental power variation from the rated value. Theoretical determination of MASURCA reactor core reactivity through the analysis of experimental data on neutron time spectra was made.

• East Asian Economic Review
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• 제28권2호
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• pp.143-174
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• 2024

This paper empirically examines the relationship between outward foreign direct investment (OFDI) of Korean manufacturing firms and the servicification of domestic employment using a firm-level panel data. In this study, considering the issue of low productivity in the Korean service sector, we categorize service employment into core and non-core services and investigate their relationship with OFDI using the firm-fixed effects model. The empirical results show that the share of core service employment exhibits a positive correlation with the extensive OFDI. On the other hand, the share of non-core service employment, which is expected to generate relatively low value-added, does not show a significant relationship with the extensive OFDI. When we divide the samples based on host countries and the type of subsidiaries, the impact on servicification varies depending on the technological capabilities of host countries and their participation in global value chains. Our study suggests that Korean manufacturing firm's internationalization strategies may facilitate a transition from labor-intensive employment, like the cases in advanced countries, to technology-intensive employment through OFDI and other means.

• Steel and Composite Structures
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• 제35권5호
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• pp.659-670
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• 2020

This paper proposes the use of a porous core between layers of laminated composite plates to examine its effect on the natural frequencies of the resulted porous laminated composite sandwich plate (PLCSP) resting on a two-parameter elastic foundation. Moreover, it has been suggested that the dispersion of porosity has two different functionally graded (FG) patterns which are compared with a uniformly dispersed (UD) profile to find their best vibrational efficiency in the proposed PLCSPs. In FG patterns, two types of dispersions, including symmetric (FG-S) and asymmetric (FG-A) patterns have been considered. To derive the governing Eigen value equation of such structures, the first order shear deformation theory (FSDT) of plates has been employed. Accordingly, a finite element method (FEM) is developed to solve the derived Eigen value equation. Using the mentioned theory and method, the effects of porosity parameters, fiber orientation of laminated composite, geometrical dimensions, boundary conditions and elastic foundation on the natural frequencies of the proposed PLCSPs have been studied. It is observed that embedding porosity in core layer leads to a significant improvement in the natural frequencies of PLCSPs. Moreover, the natural frequencies of PLCSPs with FG porous core are higher than those with UD porous core.

• Asian Journal of Business Environment
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• 제7권2호
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• pp.17-20
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• 2017

Purpose - This paper will go deep into the analysis of Korean Cultural industry development, and the result of the analysis shows that the cultural value of cultural product, competitive product lines and mature Market Mechanism are core competences of Korean Cultural industry. Research design, data, and methodology - This is a case study in the era of knowledge based economy, Cultural industry has become a new increasing point of economic development. Cultural industry, commonly regarded as an industry with high-ended value, is occupying more important role in economic development and social welfare promotion process. Results - Moreover the increasingly important role of cultural industry will hopefully help to promote industrial upgrading process and finally become a driving force for economic growth and technological innovation. During the process of cultural development, improving core competence of Cultural industry is a key consideration to help the development of Cultural industry in a positive way. Conclusions - From the study above, we find that in order to ensure sustainable development of Cultural industry, emphasis should be put on finding and improving core competence. Core competence of Korean Cultural industry is important and inspiring to the development of Chinese Cultural industry and regional integration in the East Asian area.

• 한국의류산업학회지
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• 제16권1호
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• pp.145-152
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• 2014

The usage of textile-based sensors has increased due to their many advantages (compared to IT sensors) when applied to body assessment and comfort. Textile-based sensors have different detecting factors such as pressure, voltage, current and capacitance to investigate the characteristics. In this study, textile-based sensor fabrics with sheath-core type conductive yarns were produced and the relationship between capacitance changes and applied load was investigated. The physical and electric properties of textile-based sensor fabrics were also investigated under various laminating conditions. A textile based pressure sensor that uses a sheath-core conductive yarn to ensure the stability of the pressure sensor in the textile-based sensor (the physical structure of the reaction characteristic of the capacitance) is important for the stability of the initial value of the initial capacitance value outside the characteristic of the textile structural environment. In addition, a textile based sensor is displaced relative to the initial value of the capacitance change according to pressure changes in the capacitance value of the sensor due to the fineness of the high risk of noise generation. Changing the physical structure of the fabric through the sensor characteristic of the pressure sensor via the noise generating element of laminating (temperature, humidity, and static electricity) to cut off the voltage output element to improve the data reliability could be secured.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문발표회
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• pp.31-34
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• 2003

Sandwich panel is composed of the facing sheets which support the external load, the cellular core with the low thermal conductivity and the adhesive agent to bond them. The cellular core was produced by binding lightweight cellular aggregates with cement and two types of acrylic base St/BA emulsion were added with a view to improving the workability ion due to high absorption of light weight aggregate and to develope more strength, respectively. This investigation is to comprehend the effect of the addition of two types of St/BA on thermal conductivity, calorific value and exhaustion content of noxious gas in addition re compressive and flexural strength. Flexural strength of the specimen made with St/BA-2 ranged 20kgf/cm2 to 25kgf/cm2 and was about 50% to 100% as high as that of the non-fiber specimen. Thermal conductivity was recorded from 2.0 to 3.0 kcal/mh$^{\circ}C$ and calorific value of St/BA modified specimen was much lower than that of commercial sandwich panel core of EPS and urethane. Careful caution has to be taken because generation of noxious gas such as CO, NO and SO2 tend to increase with addition of polymer cement ratio.

• 대한치과보철학회지
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• 제33권4호
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• pp.634-644
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• 1995

The purpose of this study is to evaluate the color differences in the In-Ceram according to coping thickness and various abutment core materials ; amalgam, precious alloy, composite resin, non-precious alloy. After the porcelain was built up on the In-Ceram coping at the thicknes of 0.3mm and 0.5mm then it was cemented with glass ionomer cement to the post & core materials. The following results were obtained. 1. There were significant differences in the $L^*$ values $a^*$ and $b^*$ values in the cementation of different cores, to the In-Ceram(P<0.01). $L^*$ values were not significantly different between the composite resin to the In-Ceram and the $a^*\;b^*$ values were not significantly different between the amalgam and the non-precious alloy. 2. All of cementations of In-Ceram to the core materisal had color difference(${\Delta}E^*ab$) compared to the In-Ceram. In the 0.3mm thickness of the In-Ceram copping non-precious alloy indicated the greatest value, while the composite resin core showed the lowest value with a thickness of 0.5mm In-Ceram copping. 3. By controlloing the In-Ceram coping thickness $L^*$ value was significatly different(P<0.01), but not in $a^*$ and $b^*$ values. 4. In an amalgam, precious & non-prcious alloys there was a 1,74 to 3.06 range color difference in the controlled thickness of In-Ceram coping at the thickness of 0.3mm and 0.5mm. The above results suggest that the requirement of the sufficient thickness of In-Ceram coping and the suitable core material in order to get an estheti restoration by In-Ceram and also to intercept the original core color.

• 한국철학논집
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• 제23호
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• pp.67-97
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• 2008

이 글에서는 풍류(風流)의 선배의 리더십 핵심가치에 대해 살펴보았다. 이번 연구에서 풍류의 선배로 포괄하여 연구한 선배는 모두 12인이다. 연구의 초점은 이들이 지닌 다양한 역량과 문화적 기여 중에서 풍류의 선배라는 하나의 틀로 정리하였을 때 공통적 가치를 발휘한 측면에 두었다. 핵심가치가 개인의 정체성을 지지하는 근간인 것처럼, 리더십 핵심가치는 리더십 발휘의 뿌리로 기능하는 측면이라 할 것이며, 리더십 발휘의 철학적 근거이다. 인격과 지식을 겸비한 우리의 선배는 자신의 인격적 성장과 리더십 발휘에서 공통적인 구도를 보여준다. 그것은 자신을 연마하는 단계(수신(修身), 개인영역Self)-타인과의 관계를 고려하는 단계(제가(齊家), 관계영역Relation) - 조직을 리드하는 단계(치국(治國), 조직영역Team) - 전체 사회를 위해 고민하고 영향을 미치는 단계(평천하(平天下), 사회영역Community)를 자신의 삶에서 구현하였다는 점이다. 각 선배들이 위의 네 영역에서 어떻게 리더십을 발휘하고 있는지를 사례별로 고찰한 다음, 그것을 종합한 내용을 밝힘으로써 풍류의 선배의 리더십 모형을 구성해 보았다. 그 결과 이들의 리더십 핵심가치로 '소통'이 찾아졌고, 그것을 '무애사방의 리더십'이라 명명하였다. 그리고 이것이 열린사회를 지향하고 다양한 문화의 어울림을 화두로 하는 오늘의 세상에서 여전히 유의미한 가치를 부여받을 수 있음을 확인하였다.

• 대한치과보철학회지
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• 제45권5호
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• pp.567-578
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• 2007

Statement of problem: The endodontically treated tooth is generally restored with post and core, owing to the brittle and the loss of large amount of tooth structure. As periodontal treatment was developed, there are many cases that periodontally involved teeth used in prosthetic treatment. Purpose: The purpose of this study was to analyze the stress distribution in the dentin and post structures by the various post materials and the amount of remaining alveolar bone height. Material and method: The 3-dimensional finite element models of mandible 1st premolars were divided into six types according to the various amount of remaining alveolar bone and post type. All types were modeled using equal length, diameter and shape of the post. Three types of post and core materials were used: prefabricated titaniumpost and amalgam core, prefabricated stainless steel post and amalgam core, and cast gold post and core. 300 Newton force was applied to functional cusp of mandible 1st premolar. Results: The results were as follows: First, there was no apparent difference in the pattern of stress distribution according to the alveolar bone condition concentrate on the post middle area. Second, there was difference in pattern of stress distribution according to the core materials, gold post and core generated same than amalgam core. Third, there was no apparent difference in the pattern of stress distribution within the dentin according to the post and core materials. But a cast gold post and core generated the lowest maximum stress value, a stainless steel post generated the highest maximum stress value. Fourth, in the reduced alveolar bone model, maximum stress value is 1.5 times than that of the normal alveolar bone model. Conclusion: Within the limitations of this study, to provide minimal stress to the root with alveolar bone reduced, the post length may be as long as apical seal was not destroyed. To prevent fracture of tooth, it is rational to use gold alloy which material was good for stress distribution for post materials.

• International Journal of Automotive Technology
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• 제7권4호
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• pp.485-492
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• 2006

The AA5182/polypropylene/AA5182(AA/PP/AA) sandwich sheets have been developed for application to automotive body panels in future lightweight vehicles with significant weight reduction. It has been reported that the AA5182 aluminum sheet shows $L\"{u}ders$ band because of dissolved Mg atoms that cause fabrication process problem, especially surface roughness. The examination of serration behavior has been made after the tensile deformation of the AA/PP/AA sandwich sheets as well as that of the AA5182 aluminum skins at room and elevated temperatures. All sandwich sheets and the AA5182 aluminum skin showed serration behavior on their flow curves. However, the magnitude of serration was significantly diminished in the sandwich sheet with high volume fraction of the polypropylene core. According to the results of the analysis of the surface roughness following the tensile test, $L\"{u}ders$ band depth of the sandwich sheet evidently showed lower than that of the AA5182 aluminum skin. The strain rate sensitivity, m-value, of the AA5182 aluminum skin was -0.006. By attaching these skins to the polypropylene core, which has relatively large positive value of 0.050, m-value of the sandwich sheets changed to the positive value. The serration mechanism of the sandwich sheets was quantitatively investigated in the point of the effect on polypropylene thickness variation, that on the strain rate sensitivity and that on the localized stress state.