• 한국구조물진단유지관리공학회 논문집
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• 제25권3호
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• pp.31-39
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• 2021

본 연구에서는 후크형 강섬유(HSF)와 스무스형 섬유(SSF)의 혼합 비율과 변형속도가 하이브리드 섬유보강 시멘트복합체의 인장 특성 시너지 효과에 미치는 영향을 평가하기 위하여, HSF와 SSF를 각각 1.5+0.5, 1.0+1.0, 0.5+1.0vol.%의 혼합 비율로 혼입한 하이브리드 섬유보강 시멘트복합체를 제작하였다. 실험 결과, HSF를 보강한 시멘트복합체(HSF2.0)은 변형속도가 증가함에 따라 섬유 주변 매트릭스에 발생하는 마이크로 균열의 증가에 의해 직선형으로 인발되는 섬유의 수가 감소하고, 인장강도 점 이후 응력 저하가 급격하게 발생하였다. SSF가 0.5vol.% 혼입되는 경우, 준정적에서 마이크로 균열을 효과적으로 제어하지만, 고속에서는 마이크로 균열 제어 및 후크형 강섬유의 인발저항성능 향상에 효과적이지 않은 것으로 확인되었다. 반면, HSF 1.0vol.%와 SSF 1.0vol.%를 혼입한 시험체(HSF1.0SSF1.0)은 마이크로 및 매크로 균열에 대해 각각의 섬유가 효과적으로 제어하고, SSF가 HSF의 인발저항성능을 향상시킴으로써 고속에서 변형능력 및 에너지 흡수 능력에 대한 섬유 혼합 효과가 크게 증가하였으며, 인장강도, 변형능력 및 피크인성의 변형속도 민감도가 가장 높은 것으로 나타났다. 반면, SSF 1.5vol.%의 혼입은 매트릭스 내의 섬유 혼입 개체 수를 증가시키고, HSF의 인발저항성능을 향상시켜 가장 높은 인장강도 및 연화인성 시너지 효과를 나타내었지만, 매크로 균열을 제어하는 HSF의 혼입률이 0.5vol.%로 낮아 변형능력 및 피크인성 시너지에는 효과적이지 않은 것으로 확인되었다.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2001년도 The Seoul International Simulation Conference
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• pp.280-287
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• 2001

There have been some studies about hybrid production system, which integrate push system and pull system. Most of them are based on the simple production system considering one product line. Though there are many studies about hybrid production system, it\`s not practical to implement them for real factory, because most of them did not consider various factors about real factory. On this study we designed hybrid production system considering some factor - one is automatic kanban generation, the other is dispatching rule for Multi-tasking worker, and the last one is the priority of kanban. At last, We give simulation results fur a real company, which produce various cameras in Korea.

• JSTS:Journal of Semiconductor Technology and Science
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• 제2권4호
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• pp.288-294
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• 2002

This paper presents the design, fabrication and characterization of a 32 by 32 electroplated micromirror array on a glass, a low cost substrate. Approaches taken in this work for the fabrication of micromachined mirror arrays include a line addressing scheme, a seamless array design for high fill factor, planarization techniques of polymeric interlayers, a high yield methodology for the removal of sacrificial polymeric interlayers, and low temperature and chemically safe fabrication techniques. The micromirror is fabricated by aluminum and the size of a single micromirror is 200 $\mu\textrm{m}{\;}{\times}200{\;}\mu\textrm{m}$. Static deflection test of the micro-mirror has been carried out and pull-in voltage of 44V and releasing voltage of 30V was found.

• 한국유기농업학회지
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• 제22권1호
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• pp.47-65
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• 2014

Environment-friendly agricultural products in villages for rural tourism not only are very crucial as a pull factor that attracts tourists but also can serve as a way out for the development of rural areas. Experiences of agricultural products and local dishes can revitalize rural tourism and act as attractors that draw tourists to farm villages for tourism consistently. This study examines factors affecting rural experience tourists' purchase of environment-friendly agricultural products, thereby suggesting marketing strategies for promoting the consumption of environment-friendly agricultural products of villages for rural tourism.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.333-337
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• 2008

This study investigates crack propagation behavior of Sn-3.0Ag-0.5Cu solder under pull-push loading conditions. Fatigue Crack Growth (FCG) tests were conducted on Center Cracked Plate (CCP) specimens in fast-fast (pp) strain waveform. The fast-slow (pc), slow-fast (cp) and slow-slow (cc) strain waveforms were also used to study the effect of strain rates. The crack propagation rates for the four strain waveforms were correlated with J-integral range and a scatter band of factor 4 was found. The crack growth rates for the pc waveform was highest, followed by cp, cc and then pp waveforms.

• 한국기계가공학회지
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• 제19권3호
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• pp.86-91
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• 2020

An important factor of rough road modeling is analyzing the shear behavior properties of the rough road. These properties influence the drawbar pull of the tool when interacting with the soil used in agriculture. Furthermore, shear behavior properties are important because sinkage and shear stress are generated when wheels drive on rough roads. In this study, we performed a direct shear test to investigate the shear behavior properties of soils and compare with the direct shear simulation; shear force derived by the coupled analysis of discrete element method; and multi-body dynamics. Soil contact parameters were measured in a wheel and soil contact simulation followed by comparison of the simulated and experimentally measured shear force.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
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• pp.122-123
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• 2017

In this study, the tensile behavior of single and hybrid fiber reinforced cement composite according to strain rate was evaluated. Experimental results, in the strain rate 10-6/s, fiber reinforced cement composite showed improved of tensile strength and decrease of strain at peak stress as SSF volume content increased. In the strain rate 101/s, the single and hybrid reinforced cement composite' s tensile properties are improved, because of the improved bond strength between the fiber and matrix. And hybrid fiber reinforced cement composite showed high energy absorption capacity, because the SSF prevented the cracking and fracture of the surrounding matrix when during the HSF pull-out.

• 무역학회지
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• 제47권1호
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• pp.181-198
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• 2022

This paper investigates the arbitrage effect by the covered interest parity (CIP) deviation, as well as other push or pull factor effect on capital inflows and ouflows in the Korean bond market, by utilizing OLS, TSLS, IRF and VDC in EC model. The sample period covers February 2002 to December 2020. It is found that, the swap basis reflecting the CIP deviations have the significant effects on both debt investment inflows and debt investment outflows. Also, it is found that, the Korean risk factors have decreasing effects on foreigner's investment in the Korean bonds, while the global risk factors have decreasing effects on Korean resident's investment in the foreign bonds.

• Computers and Concrete
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• 제34권2호
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• pp.231-245
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• 2024

A 3D discrete element model integrating the rough surface contact concept with the flat-joint model is suggested to examine the mechanical characteristics of the interfacial transition zone (ITZ) in concrete. The essential components of our DEM procedure include the calculation of the actual contact area in an element contact-pair related to the bonded factor using a Gaussian probability distribution of asperity height, as well as the determination of the contact probability-relative displacement form using the least square method for further computing the force-displacement of ITZs. The present formulations are implemented in MUSEN, an open source development environment for discrete element analysis that is optimized for high performance computation. The model's meso-parameters are calibrated by using uniaxial compression and splitting tensile simulations, as well as laboratory tests of concrete from the literature. The present model's DEM predictions accord well with laboratory experimental tests of pull-out concrete specimens published in the literature.

• 미생물학회지
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• 제50권2호
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• pp.95-100
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• 2014

Hrq1은 곰팡이 유전체에서 생물정보분석에 의해 발견된 새로운 RecQ helicase이다. 이 단백질은 인간의 RECQL4와 가장 상동성이 높으며 최근의 유전학적 생화학적 연구를 통해서 유전체 안정성을 유지하는데 어떤 역할을 할 것으로 예상되었다. 본 연구에서는 RECQL4와 상호작용하는 것으로 알려진 인간 유전자들과 상동성이 있는 효모 유전자들이 Hrq1과 상호작용하는지를 yeast two-hybrid assay를 이용하여 조사하였다. 총 11개의 유전자를 조사한 결과, nucleotide excision repair (NER) 인자 중의 하나인 Rad14이 Hrq1과 상호작용하는 것을 발견하였다. 또한 정제한 단백질을 이용한 pull-down assay로 Hrq1과 Rad14 사이의 직접적인 상호작용을 확인하였다. Hrq1과 Rad14 사이의 yeast two-hybrid 상호작용은 4-nitroquinoline-1-oxide에 의한 DNA 손상으로 더욱 증가하였으며, 이러한 상호작용의 증가는 또 다른 NER 인자인 Rad4에 의존적이었다. 이러한 결과들은 Hrq1이 Rad14과의 상호작용을 통하여 NER 과정에 어떤 역할을 할 가능성을 제시하고 있다.