• 한국생산제조학회지
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• 제18권3호
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• pp.241-247
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• 2009

It is important to satisfy the requirements and standards for the protections of passengers in a car accident. There are lots of studies on the crushing energy absorption of a structure members in automobiles. We have studied to investigate collapse characteristics and moisture absorption movements of CFRP(Carbon Fiber Reinforced Plastics) hat shaped sectional members when CFRP laminates are under the hygrothermal environment. In particular, the absorbed energy, mean collapse load and deformation mode were analyzed for side members which absorbed most of the collision energy. Variation of CFRP interlaminar numbers is important to increase the energy absorption capability. Therefore we have made a static collapse experiment to research into the difference of absorbed energy and deformation mode between moisture absorbed specimen and non-moisture absorbed.

• 한국생산제조학회지
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• 제18권5호
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• pp.507-513
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• 2009

It is important to satisfy the requirements and standards for the protections of passengers in a car accident. There are lots of studies on the crushing energy absorption of structure members in automobiles. We have investigated collapse characteristics and moisture absorption movements of CFRP(Carbon Fiber Reinforced Plastics) hat shaped sectional members when CFRP laminates are under the hygrothermal environment. The absorbed energy, mean collapse load and deformation mode were analyzed for side members which absorbed most of the collision energy. Therefore we have made a static collapse experiment to research into the difference of absorbed energy and deformation mode between moisture absorbed specimen and non-moisture absorbed specimen.

• Composites Research
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• 제26권6호
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• pp.349-354
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• 2013

본 논문에서는 Carbon/Epoxy 복합재 적층판에 대하여 실사격 실험을 수행하였으며, 복합재 적층판의 흡수에너지를 예측하기 위한 개선된 방법을 제시하였다. 고속충격실험 과정에서 충격체의 질량손실을 고속카메라를 통하여 거시적으로 확인하였으며, 따라서 이를 고려하여 복합재 적층판의 흡수에너지를 계산하였다. 고속충격을 받는 복합재 적층판의 흡수에너지를 예측하기 위한 모델을 제시하였으며, 복합재 적층판의 흡수에너지는 크게 정적에너지와 동적에너지로 분류하였다. 정적에너지 계산은 섬유의 파손과 정적 탄성에너지와 관련 있는 준정적 관통실험식을 통해 구한 관통에너지를 사용하였다. 동적에너지는 변형되는 시편의 운동에너지와 손실된 파편 질량들의 운동에너지로 나뉠 수 있다. 최종적으로 충격체 질량손실을 고려하여 예측된 흡수에너지와 실험결과를 비교/분석하였다.

• Carbon letters
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• 제16권4호
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• pp.241-246
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• 2015

Rapid industrial development in recent times has increased the demand for light-weight materials with high strength and structural integrity. In this context, carbon fiber-reinforced plastic (CFRP) composite materials are being extensively used. However, laminated CFRPs develop faults during impact because CFRPs are composed of mixed carbon fiber and epoxy. Moreover, their fracturing behavior is very complicated and difficult to interpret. In this paper, the effect of the direction of lamination in CFRP on the absorbed impact energy and impact strength were evaluated, including symmetric ply (0°/0°, −15°/+15°, −30°/+30°, −45°/+45°, and −90°/+90°) and asymmetric ply (0°/15°, 0°/30°, 0°/45°, and 0°/90°), through drop-weight impact tests. Further, the thermal properties of the specimens were measured using an infrared camera. Correlations between the absorbed impact energy, impact strength, and thermal properties as determined by the drop-weight impact tests were analyzed. These analyses revealed that the absorbed impact energy of the specimens with asymmetric laminated angles was greater than that of the specimens with symmetric laminated angles. In addition, the asymmetry ply absorbed more impact energy than the symmetric ply. Finally, the absorbed impact energy was inversely proportional to the thermal characteristics of the specimens.

• 한국생산제조학회지
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• 제19권6호
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• pp.782-789
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• 2010

It is important to satisfy the requirements and standards for the protections of passengers in a car accident. There are lots of studies on the crushing energy absorption of a structure member in automobiles. In this paper, we have studied to investigate collapse characteristics and moisture absorption movements of CFRP( carbon fiber reinforced plastics) structure members when CFRP laminates are under the hygrothermal environment. In particular, the absorbed energy, mean collapse load and deformation mode were analyzed for CFRP members which absorbed most of the collision energy. Also, variation of stacking angle is important to increase the energy absorption capability. The purpose of this study is to evaluate the strength reduction and moisture absorption behavior of CFRP hat shaped member. Therefore we have made a impact collapse experiment to research into the difference of absorbed energy and deformation mode between moisture absorbed specimen and non-moisture absorbed. As a result, the effect of moisture absorption and impact loads of approximately 50% reduction in strength are shown.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2003년도 제27회 추계학술대회
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• pp.69-69
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• 2003

Flat panel based digital radiography (DR) systems have recently become useful and important in the field of diagnostic radiology. For DRs with amorphous silicon photosensors, CsI(TI) is normally used as the scintillator, which produces visible light corresponding to the absorbed energy. The visible light photons are converted into an electric signal in the amorphous silicon photodiode. In order to produce good quality images, we need to understand the detailed behavior of DR detectors in radiation. We, therefore, investigated the relationship between DR outputs and X -ray in terms of absorbed energy, using the SPEC-78, X-ray energy spectrum model. We calculated the total filtration of X-ray equipment measuring air exposure and this value was used in the calculation of absorbed energy. The relationship between DR output and the absorbed energy of the X-ray was obtained by matching the absorbed energy with pixel values of real images under various conditions. It was found that the relationship between these two values was almost linear. The results were verified using phantoms made of water and aluminium. The pixel value of the phantom image was estimated and compared with previous results under various conditions. The estimated pixel value coincided with the results, although the effect of scattered photons introduced some errors.

• Nuclear Engineering and Technology
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• 제40권7호
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• pp.533-538
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• 2008

In some situations, for example at very low doses, in microbeam irradiation experiments, or around high energy heavy ion tracks, use of the absorbed dose to describe the energy transferred to the irradiated target can be misleading. Since absorbed dose is the expected value of energy per mass it takes into account all of the targets which do not have any energy deposition. In many situations that results in numerical values, in Joules per kg, which are much less than the energy deposited in targets that have been crossed by a charged particle track. This can lead to confusion about the biochemical processes that lead to the consequences of irradiation. There are a few alternative approaches to describing radiation that avoid this potential confusion. Examples of specific situations that can lead to confusion are given. It is concluded that using the particle radiance spectrum and the exposure time, instead of absorbed dose, to describe these irradiations minimizes the potential for confusion about the actual nature of the energy deposition.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.389-392
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• 2002

Digital radiography (DR) is being developed for numerous applications in medical imaging. For understanding DR image, it is necessary to comprehend DR responses to X-ray in terms of absorbed energy. This study reports on the relationship of absorbed energy in the scintillator vs. pixel value of detector. Pixel value and exposure were measured from 50 kVp to 120 kVp until the detector was saturated. For representing radiation produced at the X-ray tube, we used program Srs-78 and compared experimental exposure with calculated exposure. Absorbed energy was acquired using spectrum and we got the relation between the two values.

• Journal of Advanced Marine Engineering and Technology
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• 제12권3호
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• pp.57-67
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• 1988

Although handicapped by the inability to bridge the size gap between small laboratory sample and large engineering component, the V charpy test sample method does possess certain advantages, such as each of preparation, simplicity of test method, speed, low cost in test machinery, and low cost per test. On the other hand, the COD test method does posses advantages, which reduce the size gap between the laboratory sample and actual engineering component. Consequently, the correlation between V charpy absorbed energy and the critical COD value is required for estimating critical COD value from the simple V charpy test results. In this paper, the high tensile strength steel AH36 plate specimens having a single edge cracked notch were investigated to find out the correlation between V charpy absorbed energy and critical COD value in the welded parts under such various welding methods as shielded metal arc welding, the submerged arc welding and the electro gas welding by means of V charpy impact test and static 3-point bending test. Main results obtained are as follow ; 1. The relationships between V charpy absorbed energy Wc' and critical COD value ($\delta_c$)show; $\delta_c$=0.0065 Wc'+0.1906. 2. Ductile- brittle transition behaviours can be estimated by means of fracture appearance and general yielding behaviours. 3. The V charpy absorbed energy of SMAW is higher than that of SAW, EGW and similar relationships are obtained in the COD tests.

• 방사선산업학회지
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• 제5권4호
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• pp.359-364
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• 2011

This study was aimed to investigate the effect of oxidants on biodegradability and decomposition of acetaminophen (ACT) by gamma ray. Three kinds of chemical, potassium persulfate, hydrogen peroxide and ferrous sulfate were selected as an oxidant. The absorbed dose was ranged from 0.2 to 10 kGy and the concentration of oxidants was from 0.1 to 10 mM and the initial concentration of acetaminophen was $30mg\;l^{-1}$ in this study. The concentration of ACT was gradually decreased corresponding to the increase of the absorbed dose. However, mineralization of ACT was not occurred by the increased of the absorbed dose. When the 10 mM of oxidants applied to the ACT aqueous solution, the concentration of ACT was rapidly decreased according to absorbed dose and the mineralization was observed in potassium persulfate. Biodegradability of ACT with potassium persulfate was higher than that of ACT without potassium persulfate in lower absorbed dose and decreased according to higher absorbed dose.