• 한국산업융합학회 논문집
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• 제26권1호
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• pp.193-199
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• 2023

In this study, an analysis was conducted to analyze the structural stability of the piezoelectric power generation module and to determine the optimal burying hole interval for concrete, the installation site of the power generation module. A piezoelectric element refers to a functional ceramic having a piezoelectric direct effect that converts mechanical energy into electrical energy and a piezoelectric reverse effect. In the analysis of the piezoelectric power generation module, the load condition was applied with about 16 tons and a total of 10 wheels in consideration of the container trailer. The purpose was to evaluate the stability of major components of the piezoelectric power generation module through finite element analysis. In order to determine the optimal burying location of the concrete ground for burying the piezoelectric power generation module, the stability of the ground structure according to the distance of the holes was determined. As a result of the analysis, the maximum stress of the piezoelectric power generation module was generated in the support spring, showing a stress of about 276.7 MPa. It was found that the spacing of holes for embedding the piezoelectric power generation module should be set to a minimum of 100 mm or more.

• 한국의류산업학회지
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• 제18권6호
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• pp.878-888
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• 2016

In this study, wool/nylon(50/50%) blend yarn and its fabrics for tra-biz(complex word of travel+business) garment were prepared, and its wear comfort characteristics were investigated through thermal manikin and human-body wearing experiment. In addition, tactile wearing performance from fabric mechanical properties and the dimensional stability and the pilling of the fabric specimen during wearing and dry-cleaning were measured and compared with those of wool 100% fabric specimen. Heat keepability of the wool/nylon(50/50%) blend fabric by thermal manikin experiment was superior than that of wool 100% fabric, this result was verified with human-body wearing experiment and its result coincided well with this experimental result. Tactile wearing performance of the wool/nylon(50/50%) fabric from fabric mechanical properties measured by FAST system was better than that of the wool 100% fabric. The dimensional stability of the wool/nylon(50/50%) fabric was more stable than that of the wool 100% fabric. Because relaxation shrinkage was lower and hygral expansion of wool 100% fabric was more high. However, the breathability and pilling property of the wool/nylon(50/50%) fabric were inferior than those of the wool 100% fabric. The possibility of application for tra-biz garment of wool/nylon(50/50%) blend fabric was observed because of good heat keepability, tactile wearing performance and washing fastness.

• 한국산업융합학회 논문집
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• 제12권2호
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• pp.91-97
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• 2009

The productivity and the precision machining are the major concerns of the machine tools, and the importance of those features will be even more emphasized with the needs of the modern industries. In this paper the dynamic properties of a lathe have been investigated through the frequency analysis test and the computer simulation to minimize the transmission of vibration generated during the machining process. The modifications have been applied to the original structure to suppress the vibration transmission and further for the structure to achieve less vibrations and higher precision machining. The result shows that the machine can have much less vibrations with simple design alterations for minor expenses, the result can also be readily applied to many similar machines for improved stability.

• 펄프종이기술
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• 제43권2호
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• pp.40-48
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• 2011

To build up the conservativeness of aged paper heritages, the strength reinforcement treatment using various cellulose derivative solutions was considered. Hand-made Hanji prepared by traditional papermaking technique was firstly simulated in order to modify the overall of paper properties like aged paper heritages by accelerated ageing treatment at $150^{\circ}C$ for 24 hours, and then the ageing stability of Hanji was verified through the secondary accelerated ageing at $150^{\circ}C$ for 12 hours. The physical properties of aged Hanji were improved by applying with cellulose derivative solutions. The ageing stability for physical, optical (L, brightness, opacity, yellowness) and chemical (oxidation index, degree of polymerization) properties of aged Hanji treated with all kinds of cellulose derivative solutions was also good compared to those of untreated samples, especially using MC solution. Therefore, it was that a kind of MC solution would be well-suited for the strength reinforcement treatment of aged paper heritages.

• 한국산업융합학회 논문집
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• 제13권4호
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• pp.197-203
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• 2010

Laser welding is widely used for precision welding because of superior mechanical properties and high productivity. Generally the accuracy of the welding is determined by the distribution of the bead which is affected by the structural vibrations of the equipment. This study was originated to stabilize a laser welding machine to minimize the bead distribution for the precise joining. The structural properties of the laser welding machine have been investigated to analyze the major factors of the vibrations to cause the bead distribution. The ideas for the design improvement have been applied to the simulation model to identify the effects and further to achieve the stability design and to minimize the bead distribution. The result shows that a few simple design alterations can substantially suppress the structural vibrations and improve the welding accuracy. The procedure used for this study can also be applied to similar welding equipments for improving the structural stability and the welding accuracy.

• 디지털산업정보학회논문지
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• 제15권1호
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• pp.9-20
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• 2019

Korea's R&D investment has significantly increased in recent years. However, the efficiency of R&D investment is still in question. In order to examine the ways to improve the efficiency of R&D investment, this paper presents dynamic analysis on both quantitative and qualitative efficiency of R&D projects. A Data Envelopment Analysis(DEA)/Window method is used to analyze static and dynamic efficiencies of Industrial Material R&D projects in Korea from 2012 to 2016. As a result, statistically significant differences between quantitative and qualitative efficiency have been found. It has been observed that characteristics of Decision Making Units(DMUs) have an impact on both static and dynamic efficiencies. In particular, textile and ceramic projects showed relatively stable qualitative efficiency for a short-term perspective, while steel and chemical projects showed such stability for a long-term perspective. Among the types of project principals, universities showed relatively stable efficiency, compared with private sectors and research institutes. The results of this paper can be used as a guideline to manage the performance and stability of R&D projects' efficiency.

• 한국환경농학회지
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• 제40권3호
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• pp.194-202
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• 2021

BACKGROUND: Towards achievement of sustainable agriculture, using microbial inoculants may present promising alternatives without adverse environmental effects; however, there are challenging issues that should be addressed in terms of effectiveness and ecology. Viability and stability of the bacterial inoculants would be one of the major issues in effectiveness of microbial pesticide uses, and the changes within the indigenous microbial communities by the inoculants would be an important factor influencing soil ecology. Here we investigated the stability of the introduced bacterial strains in the soils planted with barley and its effect on the diversity shifts of the rhizosphere soil bacteria. METHODS AND RESULTS: Two different types of bacterial strains of Bacillus thuringiensis and Shewanella oneidensis MR-1 were inoculated to the soils planted with barley. To monitor the stability of the inoculated bacterial strains, genes specific to the strains (XRE and mtrA) were quantified by qPCR. In addition, bacterial community analyses were performed using v3-v4 regions of 16S rRNA gene sequences from the barley rhizosphere soils, which were analyzed using Illumina MiSeq system and Mothur. Alpha- and beta-diversity analyses indicated that the inoculated rhizosphere soils were grouped apart from the uninoculated soil, and plant growth also may have affected the soil bacterial diversity. CONCLUSION: Regardless of the survival of the introduced non-native microbes, non-indigenous bacteria may influence the soil microbial community and diversity.

• 한국항만경제학회지
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• 제39권2호
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• pp.97-110
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• 2023

본 연구는 거시경제 충격이 우리나라 해운기업 안정성에 미치는 영향을 분석하였다. 우리나라 해운기업의 부실 발생 빈도가 상대적으로 적다는 점을 고려하여 퍼스로짓모형을 통해 해운기업의 부실 확률을 추정하였다. 부실 예측모형 추정 결과, 총자산은 부실 확률과 음의 상관관계를 지닌 것으로 나타난 한편, 총부채는 부실 확률과 유의한 양의 상관관계가 있는 것을 확인할 수 있었다. 부실 예측모형 추정결과를 바탕으로 총매출, 총자산 및 총부채 충격이 해운기업 부실 확률에 미치는 영향을 스트레스 테스트하였다. 스트레스 테스트 결과, 매출 및 총자산 감소는 해운기업의 재무 안정성을 크게 악화시키는 것을 확인할 수 있었다.

• 한국수소및신에너지학회논문집
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• 제34권5호
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• pp.389-397
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• 2023

This study compares domestic and foreign research on renewable energy-based water electrolysis clean hydrogen. Domestic studies from 2010 to 2023 focused on technological efficiency, energy efficiency, and system efficiency, with few analyzing infrastructure and technology trends. Overseas research initially focused on technological efficiency and stability, but has since shifted to economic and environmental impact, policy effectiveness, industry-university-research cooperation, and sustainability. To improve water electrolysis technology production, this study suggests prioritizing technology stability over efficiency, resolving government regulations and resident acceptance issues, promoting industry-university-institute cooperation for rapid commercialization of research results, and developing a strategy for sustainable development of renewable energy-based water electrolysis technology.

• 한국산업융합학회 논문집
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• 제26권5호
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• pp.895-905
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• 2023

Mud tanks used for storing and supplying mud in mud supply systems are essential to secure structural stability according to the mud loads inside the tank. In terms of structural stability of the mud tank can be ensured by increasing the thickness of the structure. However, increasing the thickness may cause a problem of increasing production costs. In addition, this increases the weight of the tank, which can cause problems with the trailer loading weight limitation during transportation. To satisfy both these problems and structural stability, the mud tank should be optimally designed. Therefore, this study conducted an optimum design in consideration of the load of the mud tank through the structural analysis and response surface optimization method in ANSYS.