• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 추계학술발표회논문집(1)
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• pp.309-314
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• 1996

Feasibility study has been accomplished to evaluate the effectiveness of the in-vessel core debris cooling through lower cavity flooding using two dimensional finite difference scheme. The volume of cerium pool and decay power rate generated in corium pool were evaluated as important parameters to the temperature distribution on the reactor vessel lower head through previous works. In this study, the corium volume based on the System 80＋ core structure and time dependent decay power rate are considered for feasibility evaluation. In addition, preliminary plans for the in-vessel core debris cooling through lower cavity flooding as severe accident management strategy, i.e. flooding timing, method and capacity, are suggested based on the result of the numerical study, international tendency related to in-vessel core debris cooling through lower cavity flooding.

• 한국분말재료학회지
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• 제29권3호
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• pp.219-225
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• 2022

An alternative fabrication method for carburizing steel using spark plasma sintering (SPS) is investigated. The sintered carburized sample, which exhibits surface modification effects such as carburizing, sintered Fe, and sintered Fe-0.8 wt.%C alloys, is fabricated using SPS. X-ray diffraction and micro Vickers tests are employed to confirm the phase and properties. Finite element analysis is performed to evaluate the change in hardness and analyze the carbon content and residual stress of the carburized sample. The change in the hardness of the carburized sample has the same tendency to predict hardness. The difference in hardness between the carburized sample and the predicted value is also discussed. The carburized sample exhibits a compressive residual stress at the surface. These results indicate that the carburized sample experiences a surface modification effect without carburization. Field emission scanning electron microscopy is employed to verify the change in phase. A novel fabrication method for altering the carburization is successfully proposed. We expect this fabrication method to solve the problems associated with carburization.

• Genomics & Informatics
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• 제2권2호
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• pp.86-91
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• 2004

Even though it represents $6-13\%$ of human genomic DNA, Alu sequences are rarely found in coding regions. When in exon region, over $80\%$ of them are found in 3' untranslated region (UTR). Pseudogenes are an important component of human genome. Their functions are not clearly known and the mechanism of how they are generated is still debatable. Both the Alu and Pseudogenes are important research problems in molecular biology. mRNA is thought to be a prime source of pseudogene and active research is going on its molecular mechanism. We report, for the first time, that mRNAs containing Alu repeats at 3' UTR has a significantly high correlation with processed pseudogenes, suggesting a possibility that Alu containing mRNAs have a high tendency to become processed pseudogenes. It is known that about $10\%$ of all human genes have been transposed. Transposed genes at 3' UTR without Alu repeat have about two processed pseudogenes per gene on average while we found with statistical significance that a transposed gene with Alu had over three processed Pseudogenes on average. Therefore, we propose Alu repeats as a new and important factor in the generation of pseudogenes.

• 한국의상디자인학회지
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• 제9권1호
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• pp.23-33
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• 2007

Clothing exports of Korea has grown rapidly till the latter half of the 1980's, contributing Korean economic development. However from the 1990's, the amount, the world market share and the international competitiveness of clothing exports have declined. Based on these phenomena, the purpose of this study was to identify the characteristics of export articles in Korean Clothing Trade focused on the 1990's. Statistical data of clothing articles(SITC 84 : Articles of apparel & clothing accessories) were used. The relative importance, trade orientation tendency and unit price of each export clothing articles were analyzed. The results of the study were as follows. On the relative importance, trade orientation tendency and unit price of each export clothing articles, outer garments or products that required complicated production process(e.g., coats, suits, ensembles, jackets, dress) had been decreased in the portion and weakened in the export orientation tendency. But one item in a set or casual wear like trousers, skirts, blouses, shirts, Jerseys, pullovers, T-shirts has been increased in the portion and risen in the unit price. These trends means that clothing exports of Korea were more focused on those category and the international competitiveness on those articles were advanced. From these results, this study can be contributed to establish the concrete clothing export articles strategies of Korean firms.

• 대한산업공학회지
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• 제39권6호
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• pp.546-553
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• 2013

A clear increase in the average annual temperature is observed worldwide, and climate changes take place in response to that increase. This affects not only the ecosystem, but also to mankind. Of all those aspects of climate change, people are especially interested in the length of each season, and people acknowledge that the duration of spring and fall has been shortened over the past several years. Still, it is difficult to observe this kind of phenomenon with the simple analysis of dividing the seasons and calculating the duration. Therefore, this study attempted to set up a more intuitive standard which well reflects the current situation. This study also divided the daily climate into 4 states using the daily maximum and minimum temperature. Moreover, using the Hidden Markov Model, this study calculated the duration of each season and analyzed its tendency based on the daily temperature data of the last 53 years (1960~2012). According to the result, the duration of spring and fall showed mild decreasing tendency over the past 53 years, and the duration of fall decreased even more during the past 30 years in the Korean peninsula. After 1960, the start of spring was advanced, which decreased the length of winter for about 11 days. On the other hand, the duration of summer increased for about 25 days, which is consistent with the worldwide tendency of temperature increase.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.106-109
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• 2005

Springback is a common phenomenon in sheet metal forming, caused by the elastic recovery of the internal stresses after removal of the tooling. Recently, advanced high strength steels (AHSS) such as TRIP and DP are finding acceptance in the automotive industry because their superior strength to weight ratio can lead to improved fuel efficiency and assessed crashworthiness of vehicles. The major troubles of the automotive structural members stamped with high strength steel sheets are the tendency of the large amount of springback due to the high yield strength and the tensile strength. The amount of springback is mainly influenced by the type of the yield function and anisotropic model induced by rolling. The discrepancy of the deep drawn product comparing the data of from the product design induced by springback must be compensated at the tool design stage in order to guarantee its function and assembly with other parts. The methodology of compensation of the low shape accuracy induced by large amount of springback is developed by the expert engineer in the industry. Recently, the numerical analysis is introduced in order to predict the amount of springback and to improve the shape accuracy prior to tryout stage of press working. In this paper, the tendency of springback is evaluated with respect to the blank material. The stamping process is analyzed fur the front side member formed with AHSS sheets such as TRIP60 and DP60. The analysis procedure fully covers the binderwrap, stamping, trimming and springback process with the commercial elasto-plastic finite element code LS-DYNA3D.

• 한국디지털건축인테리어학회논문집
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• 제8권2호
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• pp.39-46
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• 2008

Current architecture can receive support of and command various ways of expression by more advanced technology of the present time, this means the formation of changeable external design of building, and has the tendency to be interactive non-rheological shape. Accordingly surface of building is decorated not only by the basic function and the expression of information, but also by complex narrative image structure or text, so far as recognizes human as the subject of communication, and is trying the artistic expression interacting with the general public. In various expressive tendency of current architecture surface design, such an approach from a view of an interactive art trying the communication between architecture, art, and human has the meaning of suggesting the direction of directing emotional architecture giving a present to the morderners who are growing more and more an earnest desire for experiencing culture and art in their daily life.

• Corrosion Science and Technology
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• 제7권6호
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• pp.344-349
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• 2008

Epoxy coatings were prepared to give a different corrosion protection by reacting it with two different kinds of curing agent, and then effects of the curing agents on the structure, surface hydrophobic tendency, water transport behavior and hence corrosion protection of epoxy coatings were examined using hygrothermal cyclic test, and impedance analysis. In the results of EIS, the corrosion protection of epoxy coating cured by polyamide shows better than epoxy coating cured by polyamide epoxy adduct. It was well agreed with its water transport behavior and hydrophobic tendency.

• 한국분말재료학회지
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• 제10권6호
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• pp.383-389
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• 2003

As in other areas of materials technology, the tendency towards light weight constructions becomes more and more important also for powder metallurgy. The development is mainly driven by the automotive industry looking for mass reduction of vehicles as a major factor for fuel economy. Powder metallurgy has to offer a number of interesting areas including the development of sintered materials of light metals. PM aluminium alloys with improved properties are on the way to replace ferrous pars. For high temperature applications in the engine, titanium aluminide based materials offer a great potential, e.g. for exhaust valves. The PM route using elemental powders and reactions sintering is considered to be a cost effective way for net shape parts production. Furthermore it is expected that lower costs for titanium raw materials coming from metallurgical activities will offer new chances for sintered parts with titanium alloys. The field of cellular metals expands with the hollow sphere technique, that can provide materials of many metals and alloys with a great flexibility in structure modifications. These structures are expected to be used in improving the safety (crash absoption) and noise reduction in cars in the near future and offer great potential for many other applications.

• 열처리공학회지
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• 제21권2호
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• pp.87-93
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• 2008

A variety of minor alloying elements such as Zr, Sr, Y, and Gd were added to Mg-3%Zn-0.5%Sn base alloy to form various fine precipitates and their effects on the microstructure, tensile properties, and sheet metal formability were investigated. Various very fine precipitates along with fine second phases were observed by the additions. It was found that Zr or Gd additive has a role to suppress the grain coarsening of alloy sheets during the hot working process. The Zr-added alloy showed the highest tensile elongation at $250^{\circ}C$ whereas the Gd-added alloy exhibited the best sheet metal forming characteristics in terms of CCV (conical cup value) and spring-back tendency.