• 한국산업융합학회 논문집
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• 제24권3호
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• pp.289-294
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• 2021

Tungsten (W) is used as a facing material for nuclear fusion reactors, and it is used in conjunction with structural materials such as copper alloy (CuCrZr), graphite, or stainless steel. On the other hand, since tungsten is a material with a high melting point, a method that can be manufactured at a lower temperature is important. Therefore, in this study, tungsten, which is a facing material, was attempted to be manufactured using a pressure sintering method. Material properties of sintered tungsten materials were analyzed for each solvent using two types of solvents, acetone and polyethylene glycol. The sintered tungsten material using acetone as a solvent exhibited a hardness value of about 255 Hv, and when polyethylene glycol was used, a hardness value of about 200 Hv was shown. The flexural strength of the sintered tungsten material was 870 MPa and 307 MPa, respectively, when acetone and polyethylene glycol were used as solvents. The sintered tungsten material using acetone as a solvent caused densification between particles, which served as a factor of increasing the strength.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.699-702
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• 2001

The increasing demand in industry to produce rectangular cans at the reduction by the rectangular backward extrusion process involves better understanding of this process. In 2-D die deflection and dimensional variation of the component during extrusion, punch retraction, component injection and cooling was conducted using a coupled thermal-mechanical approach for the forward extrusion of aluminum alloy and low-carbon steel in tools of steel. Backward extrusion FE simulation and experimental simulation by physical modeling using wax as a model material have been performed. These simulations gave good results concerning the prediction of th flow modes and the corresponding surface expansions of the material occuring at the contact surface between the can and the punch. There prediction are the limits of the can height, depending on the reduction, the punch geometry, the workpiece material and the friction factor, in order to avoid the risk of damage caused by sticking of the workpiece material to the punch face. The influence of these different parameter on the distribution of the surface expansion along the inner can wall and bottom is already determined. This paper deals with the influence of the geometry changes of the forming tool and the work material in the rectangular backward using the 3-D finite element method.

• 한국산업융합학회 논문집
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• 제10권3호
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• pp.143-147
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• 2007

In recents years, the statistical properties has become an important quantity for reliability based design of a component. The effects of the materials and test conditions for parameter estimation in residual strength degradation model are studied in carbon/epoxy laminate. It is shown that the correlation between the experimental results and the theoretical prediction on the fatigue life distribution using the life distribution convergence method is very reasonable.

• 펄프종이기술
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• 제35권2호
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• pp.58-64
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• 2003

Because of its tendency of making strong Hoc on the fiber surface with fines, Meogujaengi has not been valued as a material of Hanji. As an attempt to manufacture high value-added products using the material made from Jumchihanji, this study performed morphological classification and chemical component analysis and selection of pulping of Meogujaengi method. As a result, it can be concluded as follows, 1. Meogujaengi is assumed to be a local variety of Broussonetia karinoki and its outward appearance is distinguished from Broussonetia kazinoki. 2. The bast fiber of Meogujaengi is longer and thinner than that of Broussonetia papyrifera or Broussonetia kazinoki. However, because of the coarse linear of fiber tissue, there are many clusters. 3. The cluster phenomenon of Meogujaengi is nothing to do with its chemical components. Although the contents of its chemical components are different from those of Broussonetia kazinoki, no component was found that obstructs pulping. 4. The pretreatment for suppressing the occurrence of clusters of Meogujaengi was effective, and it was necessary to do secondary beating using hollander beater after beating mixed with PAM using knife beater.

• Journal of Microbiology and Biotechnology
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• 제27권11호
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• pp.1961-1970
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• 2017

Lespedeza cuneata G. Don is a traditional herb that has been associated with multiple biological activities. In this study, we investigated the antioxidative/antiaging activities and performed an active component analysis of the non-fermented and fermented (using Lactobacillus pentosus) extracts of Lespedeza cuneata G. Don. The antioxidative activities of the fermented extract were higher than those of non-fermented extracts. The elastase inhibitory activity, inhibitory effects on UV-induced MMP-1 expression, and ability to promote type I procollagen synthesis were investigated in Hs68 human fibroblasts cells. These tests also revealed that the fermented extract had increased antiaging activities compared with the non-fermented extract. A component analysis of the ethyl acetate fractions of non-fermented and fermented extracts was performed using TLC, HPLC, and LC/ESI-MS/MS to observe changes in the components before and after fermentation. Six components that were different before and after fermentation were investigated. It was thought that kaempferol and quercetin were converted from kaempferol glucosides and quercetin glucosides, respectively, via bioconversion with the fermentation strain. These results indicate that the fermented extract of L. cuneata G. Don has potential for use as a natural cosmetic material with antioxidative and antiaging effects.

• 한국산업융합학회 논문집
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• 제25권6_2호
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• pp.987-992
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• 2022

STS 410, a representative martensitic stainless steel, contains 13 % chromium and is used for building materials, automobile parts, office equipment, kitchen utensils, and tableware. In general, the strength of STS 410 changes by the carbon content, and STS 410 of low carbon has excellent toughness and high carbon has excellent abrasion resistance. In this study, a fatigue test was performed on the STS 410 material to evaluate the exact fatigue limit and to evaluate the behavior of the material against fatigue. In addition, the effect on burnishing, a kind of plastic processing that creates a smooth surface by pressing a ball or roller on the inner and outer surfaces of the material was evaluated. The fatigue limit was 509 MPa for the STS 410 material, and the result was 54.5 % of the tensile strength. The fatigue limit was 542 MPa for the specimen of diamind burnished STS 410 material, and it was 58.5 % of the tensile strength.

• Journal of Welding and Joining
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• 제32권3호
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• pp.53-59
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• 2014

The mechanical stability of solder joints in electronic devices with Sn-Ag-Cu is a continuous issue since the material was applied to the industry. Various shock test methods were developed and standardized tests are used in the industry worldwide. Although it is applied for several years, the detailed mechanism of the shock induced failure mechanism is still under investigation. In this study, the effect of external temperature was observed on large Flip-chip BGA components. The weight and size of the large package produced a high strain region near the corner of the component and thus show full fracture at around 200G level shock input. The shock performance at elevated temperature, at $100^{\circ}C$ showed degradation based on board pad designs. The failure mode and potential failure mechanisms are discussed.

• 한국정보시스템학회지:정보시스템연구
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• 제12권2호
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• pp.129-149
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• 2003

One of the important applications in Enterprise Resource Planning(ERP) systems is the Manufacturing Resource Planning(MRPII) system using Bill of Material(BOM). The manufacturing resource planning determines the quantity and timing of the production or purchase of subassemblies and raw materials needed to support the Master Production Scheduling(MPS). The bill of material is the recipe, a list of the materials needed to make a product. This paper intends to suggest a component-based materials management system using Unified Modeling Language(UML), as an application system for automobile part industry. Applying component based materials management systems designed with UML methodology, we analyzed the workflow and the document on materials management process from production planning to inventory management, and implemented a prototype of efficient materials management system, as a surrogate of existing material requirement planning(MRPI) system. To produce many other assemblies for a automobile part firm, component parts are assembled into subassemblies that are joined to assemble the finished product. Through the system suggested in this study, the level of inventory has cut down and the cost of inventory management has decreased. Also, the development method using UML makes the analysis and design phase to shorten in implementation period of MRPII system. The implementation of materials management system using CBD shows the ease of use in software reuse and the interoperability with corporate Internal information system. The result of applying object-oriented CBD technique is to minimize the risk of life cycle and facilitate the reuse of software as mentioned to limitation of information engineering methodology.

• 한국산업융합학회 논문집
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• 제24권3호
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• pp.283-288
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• 2021

A tungsten material using a pressure sintering process and a titanium sintering additive was prepared to evaluate the microstructure, and mechanical properties of flexural strength and hardness. In addition, the reliability on each hardness data was evaluated by analyzing the distribution of the hardness of the tungsten material using the Weibull probability distribution. In particular, the optimal manufacturing conditions were analyzed by analyzing the correlation between the sintering temperature and the mechanical properties of the tungsten sintered body. Although the sintering density of the tungsten material was hardly changed up to 1700 ℃, but it was increased at 1800 ℃. The hardness of the tungsten sintered material increased as the sintering temperature increased, and in particular, the tungsten material sintered at 1800 ℃ showed a high hardness value of about 1790 Hv. It showed relatively excellent flexural strength at a sintering temperature of 1800 ℃.

• 한국산학기술학회논문지
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• 제21권1호
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• pp.401-408
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• 2020

현재 우리나라의 대내외 경제여건상 소재·부품산업의 지역경쟁력을 분석해 보는 것이 매우 중요하고 필요한 연구라고 판단하고, 국내 소재·부품산업의 지역경쟁력을 분석해 보고자 하였다. 우리나라 소재·부품산업의 지역경쟁력을 분석하기 위해 5대 권역별로 다양한 산업분석을 통해 권역별 소재·부품산업의 지역경쟁력을 비교분석하였다. 다양한 산업분석을 실시해본 결과, 수도권은 산업규모는 아직 작지만 성장률이 높은 성장기 기업들이 많이 분포하고 있는 것으로 나타났다. 충청권은 산업규모도 크고 성장률도 높은 성숙기의 기업들이 많은 것으로 나타났고, 호남제주, 대경강원 및 동남권은 대체로 산업규모는 크지만 성장률이 떨어지고 있는 쇠퇴기 산업의 분포가 큰 것으로 파악되었다. 입지계수(LQ)와 노동의 상대적 효율성(RLQ)를 분석해본 결과, 지역 내 산업인력 재배치나 산업구조조정 문제는 산업의 생산성을 제고시키는 방향으로 산업정책이 수립·운용되어야 할 것을 제안하였으며, 지역의 경쟁요인(RCC)을 분석하여 권역별로 지역경쟁력을 확보한 소재·부품산업을 도출하였다. 소재·부품산업의 지역경쟁력을 분석한 본 연구는 현재 우리나라의 대내외 경제여건에서 향후 국내 지역별 소재·부품산업에 대한 지원 방향을 모색함에 있어 의미있는 시사점을 제공해 줄 수 있을 것으로 기대한다.