• 한국정밀공학회지
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• 제11권2호
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• pp.95-103
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• 1994

The purpose of this paper is to provide the experimenters who use the oblique incidence ultrasonic method for anisotropic elastic constants measurement eith some useful relations. In particular, the equivalence of the times of flight by the energy ad phase velocities, which is key to the oblique incidence method, is proved explicitly. This equivalence greatly simplifies the analysis of immersion measurement results. In oredr to correctly measure the transit time of an immersed sample using the oblique incidence, the receiving transducer should be shifted laterally, and an expression in given for this shift. A method for determining all nine elastic constants of an orthotropic material is briefly described and the measurement results are listed for SiC particulate reinforced A1 matrix composites.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2008년도 추계 학술논문 발표대회
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• pp.13-16
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• 2008

This paper is to present the performance data for improved direct setting method using tile bond for application of porcelain tile under 1 percent absorptance. For this purpose, improved direct setting method type 1 & 2(tile bond curing time 0, 24H) were compared with the conventional setting methods(including direct setting method and improved pressure setting method) in the sight of the adhesive stability of porcelain tile. It tested for tiles after 14, 28days under standard condition and severe conditions. The severe conditions were water immersion, heat ageing(70℃) and freeze-thaw cycle. On the basis of test results, the adhesive strength of direct setting method was lowest for the conventional setting methods. But improved direct setting method using tile bonds(A, B) came close to the result of improved pressure setting method using tile bonds.

• 한국멀티미디어학회논문지
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• 제22권8호
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• pp.950-959
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• 2019

The purpose of this study was to investigate the effect of integrated teaching and learning method using augmented reality for effective promotion of child - friendly attitude and environmental preservation attitude and explored its applicability. For this purpose, based on the augmented reality fairy tale, we designed an experience - oriented integrated teaching and learning method such as reading book, story - telling, drawing, environmental conservation practice activity. The experimental group was divided into two groups: augmented reality reading fairy tales (A) and children's book reading fairy tales (B). First, interest, immersion, and empathy were higher in the application environment of integrated learning teaching method based on Augmented Reality. Second, there was no difference between the two groups in content understanding. Third, in terms of expressiveness, it was verified that various expressions were expressed in the applying environment of the integrated teaching - learning method based on augmented reality through drawing activities. Fourth, in practice activities, more students were practicing in the augmented reality - based integrated teaching - learning method applied environment, and the number of practice activities of individual students was also confirmed. This study suggests that the application of the integrated teaching and learning method can enhance the effect of education when using the smart teaching media using the augmented reality in early childhood education.

• 보존과학회지
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• 제25권4호
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• pp.399-409
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• 2009

외부 환경에 노출된 철제문화재는 환경오염요인에 직접적으로 영향을 받아 부식에 취약하다. 특히 철제유물에 있어서 활성부식을 일으키는 염화이온($Cl^-$)은 반드시 제거되어야 하지만 옥외 철제문화재는 유물의 특성상 탈염의 대상에서 제외되고 있다. 그러므로 본 연구에서는 조선시대 철비를 대상으로 보존처리 및 탈염실험을 실시하였으며, 탈염은 흡습지를 이용한 탈염방법과 기존의 침적탈염방법을 함께 실시하여 그 효율성을 비교하였다. 탈염의 평가는 실체 금속 현미경, SEM-EDS, pH측정과 이온크로마토그래피(IC), XRD분석을 통하여 알아보았다. 실체 금속현미경으로 조사된 결과 부식은 층을 이루고 있으며 금속조직은 백주철로 확인된다. 또한 탈염 전 부식물에 대한 SEM-EDS분석결과 Fe와 O가 주로 검출되었으며 특히 Cl이 2.48wt%까지 측정되었다. 탈염용액에 대한 pH와 음이온을 분석한 결과에서는 흡습지를 이용한 탈염방법도 침적탈염방법과 유사한 탈염효과를 볼 수 있었다. 마지막으로 탈염 전 후 부식물에 대한 XRD분석 결과 탈염전에는 goethite, magnetite, lepidocrocite와 akaganeite가 검출되었으나 탈염 후에는 akaganeite가 검출되지 않아 흡습지를 이용한 탈염의 효과를 확인할 수 있었다. 그러므로 본 연구를 통하여 흡습지를 이용한 탈염방법에서도 기존의 침적탈염방법과 유사한 탈염효과를 확인할 수 있었다.

• International Journal of Automotive Technology
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• 제8권3호
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• pp.343-349
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• 2007

One of the useful technologies for light-weightening of components required in the automobile and machine industry is to use high strength materials. To improve material properties, the carbonizing treatment, nitrifying treatment, and shot-peening method are representatively applied. However, the shot-peening method is generally used to remove surface defect on steel and to improve the fatigue strength of the surface. Benefits of shot-peening are increasing resistance against fatigue, stress corrosion cracking, fretting, galling, erosion and closing of pores. In this paper, the effect of shot-peening on the corrosion of SUP-9 steel immersed in a 3.5% NaCl solution and corrosion characteristics from heat treatment during the shot peening process has been investigated. The immersion test was performed on four kinds of specimens. Corrosion potential, the polarization curve, residual stress etc. Were analyzed from the experimental results.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.181-181
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• 2006

We developed a novel method to fabricate a nerve guide conduit (NGC) with the porosity of submicron pore sizes (to prevent fibrous tissue infiltration) and hydrophilicity (for effective oxygen and nutrient permeation) using poly(lactic-co-glycolic acid) (PLGA) and Pluronic F127 by a modified immersion precipitation method designed by our laboratory. It was recognized that the hydrophilized PLGA/F127 (3 wt%) tube can be a good candidate as a NGC from the analyses of its morphology, mechanical strength, hydrophilicity, model nutrient permeability and in vivo nerve regeneration behavior using a rat model.

• 한국식품조리과학회지
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• 제20권6호
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• pp.684-694
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• 2004

The purpose of this study was to estimate the microbial and physicochemical quality of some raw vegetables and suggest safer methods of sanitization and storage for foodservice operations. Three sanitization methods were utilized during pre-preparation (tap water, chlorine water and electrolyzed water). Leek and Chicory were monitored as ingredient, with different storage temperatures $(3,\;10^{\circ}C)$ and periods (1, 2, 3, 4 and 7 days). The largest reduction in the microbial counts was shown with the electrolyzed water and for the case before immersion in chlorine water, performing a first washing was more effective in reducing the microbial counts than with no washing. The results showed that the storage temperature, pH, moisture content and microbial loads were important factors affecting the quality of vegetables.

• Earthquakes and Structures
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• 제15권4호
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• pp.361-367
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• 2018

In this paper, dynamic analysis of concrete pipe submerged in the fluid and conveying fluid is studied subjected to earthquake load. The structure is modeled by classical shell theory and the force induced by internal fluid is obtained by Navier-Stokes equation. Applying energy method and Hamilton's principle, the motion equations are derived. Based on Navier and Newmark methods, the dynamic deflection of the structure is calculated. The effects of different parameters such as mode number, thickness to radius ratios, length to radius ratios, internal and external fluid are discussed on the seismic response of the structure. The results show that considering internal and external fluid, the dynamic deflection increases.

• 한국해양공학회지
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• 제14권1호
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• pp.60-66
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• 2000

In order to study for corrosion behavior of reinforcing steel with oxidation layer. Experiments were done with various NaCl concentrations and with immersion time in simulated concrete pore solution(SPS) the characteristics of corrosion behavior were measured by polarization resistance method and cyclic potentiodynamic method. reinforcements were coated by epoxy except corrosion without oxidation layer and it also showed two anodic-nose. by the result of potention dynamic test the potential curve shift to low with time and anodic-nose was appeared with 3% NaCl solution after 15 days. By result of cyclic Potentiodynamic test the type of corrosion was different accoding to concentration.

• 한국전기전자재료학회논문지
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• 제12권1호
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• pp.1-10
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• 1999

In this paper, we have investigated the effects of the environmental factors on Low Molecular Weight (LMW) silicone fluid contents existing in high temperature vulcanized (HTV) silicone rubber sample, using dipping method and contact angle, current measurement. Artificial treatments such as immersion in water, elevated temperature, UV irradiation and dry band arcing under salt-fog condition are selected as the environmental factors. This results will be helpful to investigate the degradation with time and to expect a life time, because the LMW silicone content, which is important to recovery the hydrophobicity of silicone rubber surface, show different results by each environmental factors.