• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.2
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• pp.117-123
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• 2012

This paper discusses two different techniques used to measure the mechanical properties of thin films: the bulge test and the nanoindentation test. In the bulge test, a uniform pressure is applied to one side of the film. Measurement of the membrane deflection as a function of the applied pressure allows one to determine the mechanical properties such as Young's modulus, and the residual stress. A nanoindentation test is performed by pushing an indenter tip into the specimen and then withdrawing it, and then recording the indentation force as a function of the indenter position. A modified King's model is used to estimate the mechanical properties of the thin film in order to avoid the effects of the substrate layers. A combination of both the bulge test and the nanoindentation test can determine both Young's modulus and Poisson's ratio simultaneously.

• Journal of the Korean Society of Propulsion Engineers
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• v.1 no.2
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• pp.1-11
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• 1997

During hydroproof test of composite pressure vessel, acoustic emission signal was measured and analyzed to evaluate structural integrity of composite motor case. When pressure was held for 1 min. at constant pressure from low pressure level to high pressure level, the pattern of hit rate of good composite pressure vessel is increased with higher value than that of bad composite pressure vessel. This report also presents detection possibility of burst location approximately in the range of 25∼36％ of burst pressure using energy rate. In case that it is difficult to detect burst location of composite motor case, it is possible to detect burst location, i.e. structurally weak location of composite pressure vessel with applying same pressure lower than maximum expected operating pressure(MEOP) repeatedly.

• Journal of the Korean Wood Science and Technology
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• v.43 no.1
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• pp.43-51
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• 2015

Wood shrinkage, an important study subject with regard to the use of wood, has long been studied by researchers. However, when the size of a wood specimen is measured, distortion must be taken into account, which can be accomplished by applying external force on the wood specimen. However, when measuring a large number of specimens, this technique can be a lengthy process. If the size is measured and the shrinkage is calculated from images acquired with a flatbed scanner, it is possible to reduce the error in the measurement and to shorten the measurement time because the images of many specimens can be acquired with one scan. To clearly establish the boundary between a wood specimen and the background in a scan, an image threshold method was applied here. The size of a wood specimen measured by means of a scanner image was found to be longer than the value determined with a vernier caliper. The maximum pixel size of a scan image for highly accurate shrinkage calculations compared with the use of a vernier caliper was 0.053 mm/pixel.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.3
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• pp.51-55
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• 2023

Measurement of the ferroelectric polarization hysteresis curve is an important means of overall evaluation and interpretation of the ferroelectric structure and dielectric properties. If a resistive component is included in the ferroelectric sample, an error is included in the measured value of the spontaneous polarization. When configuring the electrical circuit to measure the polarization, by properly utilizing the external resistance corresponding to the resistive component included in the sample, the error due to the resistive loss of the sample was excluded and the size of the ferroelectric polarization induced inside could be accurately measured. It is expected that the displacement and dielectric characteristics of ions inside the ferroelectric can be more accurately evaluated through the evaluation of such an accurate polarization hysteresis curve.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1999.10a
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• pp.11-11
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• 1999

Sach의 Boring out 측정방법은 튜브 또는 실린더 등의 축대칭 부품의 3차원 잔류 응력을 측정하는데 적용할 수 있다. 이 방법은 잔류응력이 층제거시 이완된 변형율로부터 결정된다는 원리에 근거하고 있다. 적용시 가정사항으로는 1) 잔류응력 분포가 축대칭이어야 하고 2) 응력 분포가 축방향을 따라 균일해야 한다는 것이다. 그러나 실제부품은 길이가 제한되어 있기 때문에 잔류응력 분포가 균일하다는 가정이 적용될 수 없다. 본 연구에서는 시편의 길이 대 외경 비를 변화시켰을 때 유한요소해석을 이용하여 층제거시 이완된 변형율로부터 계산된 측정값과 유한요소 해석값을 비교하여 이 측정방법의 적용한계와 타당성을 조사하였으며 얻어진 결론은 다음과 같다. Sach의 Boring out 측정방법을 적용하기 위해서는 부품의 외경 대 길이 비가 3이상일 경우 측정값과 해석값은 거의 일치하는 경향을 보이며 비가 증가할수록 측정오차가 줄어들 것으로 판단된다.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.11a
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• pp.15-19
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• 2002

기존 형상의 미세 가열기를 이용한 마이크로 시스템 패키징의 문제점을 해결하기 위해 새로운 형상의 미세 가열기를 제작하여 패키징 실험을 실시하였다. 기존 형상의 미세 가열기와 새로운 미세 가열기의 형상을 각각 제작하여 접합시에 미세 가열기에 발생하는 열분포를 IR 카메라를 이용하여 실험하였다. 기존 형상의 미세 가열기가 불균일하게 가열되는 반면, 새로운 형상의 미세 가열기는 매우 균일하게 가열되는 형상을 나타내었다. IR 카메라 실험을 바탕으로 접합 실험을 실시하였다. 접합 실험시 사용한 미세 가열기는 폭 50$\mu\textrm{m}$, 두께 2$\mu\textrm{m}$로 제작하였으며, 0.2 Mpa의 압력을 Pyrex glass cap에 가한 상태에서 150 mA의 전류를 공급함으로서 접합을 완료하였다. 접합이 완료된 시편들에 대해서 IPA를 통한 leakage 실험을 실시하였으며, 기존 형상의 미세 가열기를 이용한 시편들은 66%가 테스트를 통과한 반면 새로운 형상의 미세 가열기를 이용한 시편들은 85% 이상이 테스트를 통과하였다. Leakage 실험을 통과한 각각의 시편들에 대해서 접합력 측정을 실시한 결과, 기존 형상의 미세 가열기를 이용한 시편들은 15~21 Mpa의 접합력을 나타내었고, 새로운 형상의 미세 가열기를 이용한 시편들은 25~30 Mpa의 우수한 접합력을 나타내었다.

• Journal of Radiation Protection and Research
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• v.36 no.4
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• pp.200-208
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• 2011

The neutron fluence measurement and evaluation technology is very important for material irradiation test. The most essential technology in this study is the neutron irradiation evaluation method using a fluence monitor. The fluence monitors were fabricated with metal wires of the purity ${\geq}$ 99.9%, whose dimensions were 0.1mm diameter, about 3 mm length, and around 150-200 ${\mu}g$ mass range. Three wire samples (Fe, Ni, Ti) were prepared for one irradiation aluminum capsule. Five capsules were irradiated in the OR5 hole of the HANARO reactor at 30 MW power for about 25 days. After irradiation tests, radiation activities were measured with the high purity germanium (HPGe) detector. The reaction rates were calculated by using the measured radiation activity data, and then neutron fluence were obtained from the reaction rates and the weighted neutron cross section with calculated neutron spectrum at the fluence monitor position.

• Electrical & Electronic Materials
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• v.6 no.2
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• pp.109-114
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• 1993

본 논문에서는 0.05Pb(Sn$_{1}$2/Sb$_{1}$2/)-0.35PbTiO$_{3}$-0.60PbZrO $_{3}$+0.4[wt%] MnO$_{2}$ 조성을 갖는 3성분계 압전세라믹스에 Cr$_{2}$O$_{3}$ 의 첨가량을 변화시켜서 지연선을 제작하고 탄성표면파를 여기시켜 전파속도를 측정하였으며 EMMAS 기준에 따라 각 시편의 재료정수를 측정하고 이를 압전방정식에 적용하여 매질에 따라 여기되는 탄성표면파의 계산속도를 이론적으로 산출한 후 이를 지연선에서 측정된 실험속도와 비교하여 재료의 특성이 탄성표면파의 전파특성에 미치는 영향을 조사하였다. 그 결과 SAW 지연선에서 측정된 탄성표면파는 Generalized Rayleigh Wave였으며 재료의 특성이 우수한 시편일 수록 계산속도와 측정속도와의 차가 적었던 것으로 나타났고 오차한도는 평균 99.39[%]였으므로 실험속도 측정방법이 feed through 현상없이 우수한 측정방법이었음을 알 수 있었다.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.04a
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• pp.220-225
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• 1998

레이다를 이용한 콘크리트 구조믈의 지진으로 인한 손상도를 파악하기 위해, 콘크리트의 전자기적 특성(dielectric properties)을 레이다 작용 주파수 대역인 200MHz에서 6GHz 영역까지 측정하였다. 이의 측정을 위해 실험실에서 콘크리트의 전자기적 특성 계측을 가능하게 하는 회로망분석기(network analyser)를 사용하였다. 콘크리트의 전자기적 특성은 open-ended coaxial probe를 회로망 분석기에 연결하여 측정하였고, 실험전 측정값을 보정(calibration)하는 기법을 찾아내었다. 주파수의 변화와 함께 콘크리트 시편안에 포함된 수분의 양을 조절함으로써, 실제 콘크리트 구조물이 가질 수 있는 상태를 시편을 통해 측정하였다. 측정결과는 콘크리트의 전자기적 특성이 주파수와 수분함량에 따라 변하는 것을 보여주었으며, 이는 레이다를 이용한 콘크리트 구조물의 지진 손상도 파악 방법 개발에 필요한 자료를 제공하였다.

• Journal of Adhesion and Interface
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• v.2 no.4
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• pp.32-38
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• 2001

Effects of the ratio of rubber composition on covulcanization and ozone resistance were studied in this study. Specimens used in this study were rubber compounds(specimen-A) blended with various ratio of NR, SBR, BR, IIR, and EPDM, unsaturated rubber compounds(specimen-B) with NR/BR/SBR, and saturated rubber compounds(specimen-C) with NR/IIR/EPDM. PAD adhesion specimen was prepared from vulcanizing specimen-A and B, and specimen-A and C, respectively. Using same adhesion specimen, peel strength was measured and tested ozone resistance. In specimen-A, peel strength was higher with increasing NR ratio for NR and BR contained blends. In other specimen-A containing NR and SBR, the peel strength was also increased with increasing SBR ratio. NR/BR/IIR/EPDM rubber compounds had also better adhesion property than NR/SBR/IIR/EPDM compounds. As more unsaturated rubber was blended, the peel strength was higher but ozone resistance was worse. Optimum ratio of unsaturated and saturated rubbers for the peel strength and ozone resistance was 60/40.