• 소성∙가공
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• 제33권1호
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• pp.18-35
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• 2024

In the present work, the evolution rules for the internal variables including continuum damage factors are obtained using the thermodynamic framework, which are in turn facilitated to derive the elastic-plastic constitutive relation for the particulate composites. Using the Mori-Tanaka scheme, the homogenization on state and internal variables such as back-stress and damage factors is carried out to procure the rate independent plasticity relations. Moreover, the degradation of mechanical properties of constituents is depicted by the distinctive damages such that the phase and interfacial damages are treated individually accordingly, whereas the kinematic hardening is depicted by combining the Armstrong-Frederick and Phillips' back-stress evolutions. On the other hand, the present constitutive relation for each phase is expressed in terms of the respective damage-free effective quantities, then, followed by transformation into the damage affected overall nominal relations using the aforementioned homogenization concentration factors. An emphasis is placed on the qualitative analyses for strain localization by observing the perturbation growth instead of the conventional bifurcation analyses. It turns out that the proposed constitutive model offers a wide range of strain localization behavior depending on the evolution of various internal variable descriptions.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2010년 춘계학술발표회 논문집
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• pp.355-358
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• 2010

The objective of this study is to predict and minimize annual damage by flood. We approached this problem by implementing simple algorithm instead of using commercial programs. The biggest weak area was selected as the simulated damage range per rainfall scenario.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 춘계 학술발표회논문집
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• pp.93-100
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• 2003

Seismic isolation systems can improve the seismic safety of nuclear power plants by decreasing seismic force transmitted to structures and equipment. This study evaluates the effectiveness of equipment seismic isolation systems by the comparison of core damage frequencies in non-isolated and isolated cases. It can be found that the seismic isolation systems increase seismic capacity of nuclear equipment and decrease core damage frequencies significantly. The effect of equipment isolation is more significant in the PGA range of 0.3g to 0.5g.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.181.1-181.1
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• 2003

Polyphenolic compounds have been reported to exhibit a wide range of pharmacological properties. In this study. we investigated the hepatoprotective effect of skin and seed of grape which contain abundant polyphenol compounds on dimethylnitrosamine(DMN)-induced liver damage in rats. Ingestion of skin and seed of grape (10％ diet, daily for 4 weeks) into the DMN-treated rats remarkably prevented the elevation of serum alanine transaminase, aspartate transaminase and alkaline phosphatase, and bilirubin levels. (omitted)

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.180.1-180.1
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• 2003

Proanthocyanidins, one of the major natural polyphenolic compounds of grape has been reported to exhibit a wide range of pharmacological properties. In this study, we investigated the hepatoprotective effect of proanthocyanidins on the dimethylnitrosamine (DMN)-induced liver damage in rats. Oral administration of proanthocyanidins (20, 50mg/kg daily for 4 weeks) into the DMN-treated rats remarkably prevented the elevation of serum alanine transaminase, aspartate transaminase and alkaline phosphatase, and bilirubin levels. (omitted)

• 대한원격탐사학회지
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• 제36권5_4호
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• pp.1255-1266
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• 2020

본 연구에서는 화학사고에 따른 인명피해 저감을 위해서 신속하고 정확한 화학물질 확산 범위 예측을 위한 복합시뮬레이션 프로토타입을 개발하였다. 복합시뮬레이션은 화학물질의 누출 특성을 고려하고자 근거리 확산과정에서 누출 운동량을 고려하였다. 원거리 확산과정에서는 사고지점 주변의 기상 및 지형정보를 이용하여 획일적으로 제시되었던 기존 모델의 바람 분포를 개선하여 실제와 유사한 바람장을 구현하였다. 개선된 근·원거리 확산과정에 따라 최종적으로 피해확산 범위는 기존의 모델에 비해서 정밀한 분포를 나타냈다. 본 연구에서 개발된 복합시뮬레이션의 시간대별 피해 범위 예측 결과 통해서 화학사고 발생 후 주민 대피 및 복귀 등 정책적 의사결정의 지원시스템으로서 활용도가 높을 것으로 기대된다.

• Nuclear Engineering and Technology
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• 제52권4호
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• pp.827-834
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• 2020

Damage of tungsten due to helium ions of a PF device was studied. The tungsten was analyzed by SEM and AFM after irradiation. SEM revealed fine bubbles of helium atoms with diameters of a few nanometers, which join and form larger bubbles and blisters on the surface of tungsten. This observation confirmed the results of molecular dynamics simulation. SEM analysis after etching of the irradiated surface indicated cavities with depth range of 35-85 nm. The average fluence of helium ion of the PF device was calculated about 5.2 × 10¹⁵ cm^-2 per shot, using Lee code. Energy spectrum of helium ions was estimated using a Thomson parabola spectrometer as a function of dN/dE ∝ E^-2.8 in the energy range of 10-200 keV. The characteristics of helium ion beam was imported to SRIM code. SRIM revealed that the maximum DPA and maximum helium concentration occur in the depth range of 20-50 nm. SRIM also showed that at depth of 30 nm, all of the tungsten atoms are displaced after 20 shots, while at depth of higher than 85 nm the destruction is insignificant. There is a close match between SRIM results and the measured depths of cavities in SEM images of tungsten after etching.

• 대한물리치료과학회지
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• 제28권2호
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• pp.19-29
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• 2021

Background: The purpose of this study was to investigate the effects of pulsed-ultrasound intervention and continued-ultrasound on the MVIC (maximal voluntary isometric contraction) and active ROM (range of motion) recovery of before EIMD (exercise-induced muscle damage). Design: Randomized controlled trial. Methods: Thirty subjects who are student in their 20s at a university participated in this study, these subjects were assigned into three groups, a control group (n=10), experiment group I (n=10) and experiment group II (n=10). The subjects in experimental group were intervened by pulsed-ultrasound and continued-ultrasound, while ones on control group weren't by any intervention after induced EIMD. Results: First, In comparison of the MVIC, in the among group comparison, the MVIC of continued-ultrasound group was significantly larger than those of other groups (p<.005). Second, In the among group comparison, the active extension angle of continued-ultrasound group was significantly smaller than those of other groups (p<.005). Third, In the among group comparison, the active flexion angle of continued-ultrasound group was significantly lager than those of other groups (p<.05). Conclusion: The above results revealed that the continued-ultrasound intervention before an exercise had a significantly improve of muscle function after EIMD. Therefore we can consider the continued ultrasound as a considerable intervention method to prevent or reduce an exercise injury.

• 항공우주정책ㆍ법학회지
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• 제27권1호
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• pp.103-122
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• 2012

오늘날 우주과학과 기술의 급격한 발달로 선진국을 비롯한 국제사회에서는 우주활동을 통한 다양한 서비스와 이익을 제공되는 반면, 각종 우주물체의 충돌과 폐기물 증가 등으로 인해 인류의 활동과 우주환경 보존면에서 피해발생 가능성이 높아지고 있다. 우주활동으로 인한 사고 및 위험으로부터 피해를 입은 자에게 정당하고 충분한 배상을 해주기 위해 현재의 국제법 질서를 형성하고 있는 우주조약과 우주책임협약의 내용을 먼저 검토하고, 이를 토대로 배상의 핵심적인 요건이 되고 있는 손해의 개념과 범위를 제시하였다. 손해의 개념은 육체적 침해만이 아니라 정신적 사회적 안녕의 침해가 포함된다고 보아야 할 것이다. 따라서 고통을 수반하는 정신적 침해도 당연히 손해의 범주에 포함된다고 할 수 있을 것이다. 따라서 책임협약상 인적 손해로는 사망은 물론 우주활동의 결과로 희생자들이 입은 육체적, 정신적 손해에 대해 직접손해이던 간접손해이던 배상할 의무가 있다. 이 근거에 의해 실제로 피해 배상을 청구할 때 그 피해자는 사고가 일어나지 않았던 상태로 회복하는 것이 최선의 보상이라는 개념과 연결된다고 볼 수 있다. 아울러, 환경오염의 배상 가능성, 위성자료 전송과 관련된 문제, 손해발생의 장소 등과 같은 문제들에 대한 논의를 시도하였다. 또한, 우주법재판소와 지역적 협력 기구를 설립하는 방안을 제안한다.

• Journal of Advanced Research in Ocean Engineering
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• 제1권4호
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• pp.198-210
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• 2015

This paper presents the damage assessment of a free-fall dropped object on the seabed. The damage to a dropped object totally depends on the relationship between the impact energy and the soil strength at the mudline. In this study, unexpected dropping scenarios were first assumed by varying the relevant range of the impact velocity, structure geometry at the moment of impact, and soil strength profile along the penetration depth. Theoretical damage assessments were then undertaken for a free-fall dropping event with a fixed final embedment depth for the structure. This paper also describes the results of a three-dimensional large deformation finite element analysis undertaken for the purpose of validation. The analyses were carried out using the coupled Eulerian-Lagrangian approach, modifying the simple elastic-perfectly plastic Tresca soil model. The validation exercises for each dropping scenario showed good agreement, and the present numerical approach was capable of predicting the behavior of a free-fall dropped object.