• Proceedings of the KWS Conference
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• 2004.05a
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• pp.141-143
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• 2004

본 실험에서 SA508 CL.3 강재의 서브머지드아크 용접부에 대한 연구로 입열량의 차이에 따라서 인성과 미세조직과의 관계를 조사하였다. 강도가 크면 인성이 작아지고 연성이 작아지는 것을 확인하고, 입열량이 3-5kJ/$\textrm{mm}^2$를 표준으로 하는데, 본 실험에서는 1.6kJ/$\textrm{mm}^2$, 3.2kJ/$\textrm{mm}^2$, 5.0kJ/$\textrm{mm}^2$ 세 가지 조건으로 실험해 보았다. (중략)

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.1
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• pp.96-104
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• 1989

The behaviors of acoustic emission emitted in the tests of the fracture toughness and fracture stability are observed by using the specimens of aluminum 2024-T351 and 7039-T6 alloys. The empirical eqution of J-R curve is derived. It is demonstrated from the comparison of the fracture toughness obtained from J-R curve with that from ASTM standard E813-81 that the latter is larger than the former. The discontinuous point in the log-log graph of J-integral vs. total acoustic emission count is observed in between the two offset lines referred from ASTM standard E813-81, but it's physical meaning is uncretain. An empirical material tearing modulus is derived in terms of the total acoustic emission count and proved to be valid in fracture instability test.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.5778-5788
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• 2015

In this study, wet surface heat transfer and friction characteristics of compound enhanced fin-and-tube heat exchangers were experimentally investigated. Louver-finned heat exchangers were also tested for comparison purpose. The effect of fin pitch on j and f factor was negligible. Both j and f factor decreased as number of tube row increased. Compound enhanced fin samples yielded higher j and f factors than louver fin samples. For one row, j and f factors of compound enhanced fin samples were 11% and 43% higher than those of louver fin samples. For two row, those were 8% and 50%, and for three row, those were 17% and 53%. Heat transfer capacities at the same pressure drop of the compound enhanced fin samples were 2.0% for one row, 3.1% for two row and 8.4% for three row larger than those of louver fin samples, Data were compared with predictions of existing louver fin correlations.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.1
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• pp.73-80
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• 2022

In this study, details of NRC beam-column connections were developed in which beam and columns pre-assembled in factories using steel angles were bolted on site. The developed joint details are NRC-J type and NRC-JD type. NRC-J type is a method of tensile joining with TS bolts to the side and lower surfaces of the side plate of the NRC column and the end plate of the NRC beam. NRC-JD type has a rigid joint with high-strength bolts between the NRC beam and the side of the NRC column for shear, and with lap splices of reinforcing bar penetrating the joint and the beam main reinforcement for bending. For the seismic performance evaluation of the joint, three specimens were tested: an NRC-J specimen and NRC-JD specimen with NRC beam-column joint details, and an RC-J specimen with RC beam-column joint detail. As a result of the repeated lateral load test, the final failure mode of all specimens was the bending fracture of the beam at the beam-column interface. Compared to the RC-J specimen, the maximum strength of the specimen by the positive force was 10.1% and 29.6% higher in the NRC-J specimen and the NRC-JD specimen, respectively. Both NRC joint details were evaluated to secure ductility of 0.03 rad or more, the minimum total inter-story displacement angle required for the composite intermediate moment frame according to the KDS standard (KDS 41 31 00). At the slope by relative storey displacemet of 5.7%, the NRC-J specimen and the NRC-JD specimen had about 34.8% and 61.1% greater cumulative energy dissipation capacity than the RC specimen. The experimental strength of the NRC beam-column connection was evaluated to be 30% to 53% greater than the theoretical strength according to the KDS standard formula, and the standard formula evaluated the joint performance as a safety side.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.297-301
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• 2000

ELF 전자파의 생물학적인 영향 평가를 위한 in vitro 세포 실험에서 노출장치의 설계는 코일내피 유도기전력(E)과 전류밀도(J) 해석과 함께 이루어져야 한다. 균일 자기장 속에서 세포를 배양할 경우애도 배양기내의 전도성 매질로 인해 균일한 E와 J가 분포하지 않는다. 따라서 균일한 ELF 자기장 노출장치로부터 발생되는 샘플 매질 내에서의 E나 J를 정확히 예측하는 것은 in vitro 세포실험의 성공여부를 가늠 할 정도로 매우 중요한 정보가 된다. 이에 본 논문에서는 in vitro 실험에 적합한 ELF in vitro 노출 장치를 설계하고 노출 장치에 대한 전자기학적 평가를 수행하였다. 코일 내에서 샘플 매질의 유무와 샘플 내에서도 세포가 놓여질 임의의 위치에 따라 E와 J를 예측하고 검증을 위한 측정과 시뮬레이션을 시도하였다. 노출장치는 헬름 홀쯔 코일로 제작되었고 자기장의 세기는 1-2OG 범위 내에서 가변이 가능하다. 또한 코일내의 자기장의 분포가 균일(uniform), 비균일(nonuniform)만 두 가지모드를 각각 제작하여 보았다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4364-4374
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• 2015

In this study, heat transfer and friction characteristics of compound enhanced fin-and-tube heat exchangers were experimentally investigated. Louver-finned heat exchangers were also tested for comparison purpose. The effect of fin pitch on j and f factor was negligible. The j factor decreased as number of tube row increased. However, f factor was independent of number of tube row. Louver fin samples yielded higher j and f factors than compound enhanced fin samples. For one row, j and f factors of louver fin were 23% and 27% higher than those of compound enhanced fin. For two row, those were 11% and 8%, and for three row, those were 10% and 9%. However, heat transfer capacities at the same pressure drop of the compound enhanced fins were 6.4% for one row, 11.1% for two row and 13.6% for three row larger than those of louver fins, Existing louver fin correlation overpredicted the present j factors and underpredicted the present f factors.

• Journal of Digital Convergence
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• v.11 no.9
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• pp.365-370
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• 2013

This mouse calvarial defected model is frequently used for new scaffold development in the bone regeneration. Most experiments are carried out in this way by measuring the bone regeneration of mouse calvaria defected area. As a next step, hematoxylin and eosin staining is analyzed by sacrificing mice On the other hand, the quantitative analysis for bone regeneration is carried out by micro computed tomography. However, there are several drawbacks with the micro computed tomography. That is, it takes a long time and it is quite expensive for bone regeneration quantitative analysis. This study was performed by simply measuring the quantity of bone regeneration in mouse clavaira defected area on two-dimensional digital x-ray images via Image J. Consequentially, this experimental method by using J program might help bio-technologist researcher regarding new bone regeneration by comparing the quantity of bone regeneration quickly and precisely as well.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.165-166
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• 2006

343 kV GIS 다빈도 조작 CB 내부에 접점이 마모되어 많은 파티클이 발생한다. 이러한 파티클이 GIS 네부에 존재할 때 어떠한 영향을 미치는지 이론적으로 근거를 제시하고, 이를 실험적으로 검증을 하였다. 현장에서 수거한 파티클을 설치 운영중인 PDMS 장비와 HAEFELY 장비를 이용하여 실험용 GIS에 삽입후 발생하는 현상들을 동시에 비교 분석하고자 한다.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05a
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• pp.796-802
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• 1995

본 연구의 목적은 원자력 배관용 스테인레스강의 J-R곡선을 예측하기 위한 2가지 방법 올 제시하는 것이다. 첫 번째 방법에서는 균열길이/시편폭 비를 변수로 한 탄소성 유한요소해석을 수행하여 파괴변형률에 근거한 P-$\delta$곡선을 얻고, 이 결과로부터 일반궤적법을 응용하여 J-R곡선을 구하였다. 두 번째 방법에서는 $\sigma$-$\varepsilon$곡선과 J-R곡선의 상관관계를 통계처리하여 응력-변형률시험결과로부터 J-R곡선을 예측할 수 있는 실험식을 제시하였다. 본 연구에서 제시한 방법들을 이용하여 구한 예측결과는 실험결과와 대체로 잘 일치하였다.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.167-173
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• 2023

The purpose of this study was to analyze the accuracy of artificial respiration and chest compressions using CPR mannequins for university students. First, in the number of chest compressions, subjects A, F, H, I, and J showed similar numbers from 60 to 63, respectively, which were much lower than the standard. Subjects B, D, E, and G showed 90 to 91 times, maintaining the normal range. However, C was rather high with 119 times. Second, the depth of chest compression was 58.60mm, and most of them were deeply compressed. Subject C was close to normal at 51mm, and subjects A to J were significantly higher at 55mm to 62mm. The reason seems to be the result of an unstable psychological state with no experience of chest compressions and a lack of self-confidence. Third, in terms of accuracy, subject E showed the lowest accuracy at 12%, and A~J showed 33%~80%. Experiment subject B showed 95% accuracy, which seems to be the result of D accurately recognizing the chest compression point through theoretical training during military service.