• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.249-256
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• 2006

New infrastructures and buildings are being constructed increasingly in congested urban areas, and excavation-induced ground movements often cause distortion and damage to adjacent buildings. Protection of adjacent structures occupies a major part of the cost, schedule and third-party impacts of urban development. To limit damage or mitigate their effects on nearby structures, it is highly important to understand the whole mechanism from excavation to building damage, and to estimate building damage reliably before excavation and provide appropriate measures. This paper investigates the effects of excavation-induced ground movements on nearby structures, considering soil-structure interactions for ground and structures, and a building damage criterion, which is based on the state of strain, is proposed. The criterion is compared with other existing damage estimation criteria and a procedure is finally provided for estimating building damage due to excavation-induced ground movements.

• 터널과지하공간
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• 제18권6호
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• pp.457-464
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• 2008

암반 굴착기술의 고속화 및 정밀한 암반손상평가를 위해서는 암석의 동적파괴 메커니즘에 관한 연구가 중요하다. 본 연구에서는 충격파형 제어 Split Hopkinson Pressure Bar (SHPB) 시스템을 이용하여 모의 암석시료에 단계별 충격하중을 가하여 취성재료의 동적파괴 특성 및 동적손상메커니즘을 분석하였다. 실험시료의 손상도 평가를 위하여 충격실험 전후에 모든 시료에 대하여 P파 및 S파 속도를 측정하였으며, 탄성파 속도 감쇠정도에 따른 손상도를 평가하였다. 모의 연암 시료와 경암 시료의 탄성파 속도 감쇠비는 충격하중이 증가함에 따라 비슷한 수준으로 증가하는 경향을 보였으나, 최종 변형률의 경우 모의 연암 시료에서 현저히 높은 값을 나타내었다.

• 대한한의학원전학회지
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• 제31권4호
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• pp.1-16
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• 2018

Objectives : The paper studies the epistemology of Wind Herbs, its origin, its drug category and medicinal property, attempted to understand Lidongyuan's framework of mechanism of internal damage and treatment principle, and why he used it from his viewpoint. Methods : His suggestion was based on this treatment of internal damage suing wind herbs. Therefore, it cannot be viewed as a simple herbological concept. It rather displays the characteristics of medication based on clinical pathology. Therefore, wind herb should be comprehensively understood from the understanding of the mechanism of internal damage. That is why the paper studied around Piweilun, where Lidongyuan's concept on internal damage is established with finality. Additionally, the paper also referred to Wanghaogu's Tangyenbencao, a text that comprehensibly assembles the authors of Zhangyuans, Yixuqiyan's and Yishuixuepi's knowledge o herbology. Results : The origin of wind herb is 'herbs that uses the unique nature of wind in treatment of disease.' Medication unfolds yang qi, and this signifies the Shengyang function. This means that it starts from the lower energizer yin aspect, which is the beginning point of yang qi, and unfolds to the whole body through upbearing and effusion. Instead of producing yang qi directly similar to pungent, sweet and warm formula, however, it contributes to the achievement of the final purpose of the way of Shengyang through forming a ascending mechanism in the whole body via yin aspect's yang qi upbearing and effusion. Conclusions : Wind herb is within the scope of clinical herbology selected by Lidongyuan, for the purpose of achieving comprehensive clinical purposes, in order to treat internal damage. In this way, wind herb is distinguished from the application of other medicines that are limited in usage depending on Qiwei.

• Geomechanics and Engineering
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• 제38권1호
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• pp.57-68
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• 2024

Tunnels offer myriad benefits for modern countries, and understanding their behavior under loads is critical. This paper analyzes and evaluates the damage to buried horseshoe tunnels under soil pressure and traffic loading. To achieve this, a numerical model of this type of tunnel is first created using ABAQUS software. Then, fracture mechanics theory is applied to investigate the fracture and damage of the horseshoe tunnel. The numerical analysis is based on the damage plasticity model of concrete, which describes the inelastic behavior of concrete in tension and compression. In addition, the reinforcing steel is modeled using the bilinear plasticity model. Damage contours, stress contours, and maximum displacements illustrate how and where traffic loading alters the response of the horseshoe tunnel. Based on the results, the fracture mechanism proceeded as follows: initially, damage started at the center of the tunnel bottom, followed by the formation of damage and micro-cracks at the corners of the tunnel. Eventually, the damage reached the top of the concrete arch with increasing loading. Therefore, in the design of this tunnel, these critical areas should be reinforced more to prevent cracking.

• 생물정신의학
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• 제14권4호
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• pp.221-231
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• 2007

Recent researches have shown that important cellular-based autoprotective mechanisms are mediated by heat-shock proteins(HSPs), also called 'molecular chaperones'. HSPs as molecular chaperones are the primary cellular defense mechanism against damage to the proteome, initiating refolding of denatured proteins and regulating degradation after severe protein damage. HSPs also modulate multiple events within apoptotic pathways to help sustain cell survival following damaging stimuli. HSPs are induced by almost every type of stresses including physical and psychological stresses. Our nervous system in the brain are more vulnerable to stress and damage than any other tissues due to HSPs insufficiency. The normal function of HSPs is a key factor for endogenous stress adaptation of neural tissues. HSPs play an important role in the process of neurodevelopment, neurodegeneration, and neuroendocrine regulation. The altered function of HSPs would be associated with the development of several neuropsychiatric disorders. Therefore, an understanding of HSPs activities could help to improve autoprotective mechanism of our neural system. This paper will review the literature related to the significance of HSPs in neuropsychiatric field.

• Composites Research
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• 제12권4호
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• pp.62-70
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• 1999

건축 구조물의 재령이 증가함에 따른 손상은 구조물의 안전성 및 신뢰성 확보에 매우 심각한 문제이다. 최근에는 이렇게 손상을 입은 콘크리트 구조물의 보수 보강을 위해 탄소섬유시트가 광범위하게 사용되고 있지만 탄소섬유시트를 보강한 콘크리트의 파괴기구가 명확하게 규명되지 않았다. 따라서 본 연구에서는 탄소섬유시트를 보강한 콘크리트의 손상거동 및 미시적 파손기구를 이해하기 위해 4가지 경우의 시험편, 즉 순수한 콘크리트, 철근 보강 콘크리트, 탄소섬유시트 보강 콘크리트, 철근과 탄소섬유시트 보강 콘크리트 시험편에 대하여 3점 굽힘 시험을 실시하였다. 이러한 시험편들의 파손기구를 명확히 하기 위해 음향방출기법이 사용되었으며 균열 발생, 성장을 모니터링하기 위해 2차원 AE 발생원 위치추정 기법이 적용되었다.

• Toxicological Research
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• 제18권2호
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• pp.159-165
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• 2002

Recently, we reported (korean J. Biomed. Lab. Sci., 6(4): 245-251, 2000) that cyclohexane (l.56 g/kg of body wt., i.p.) administration led to lung injury in rats. However the detailed mechanism remain to be elucidated. This study was designed to clarify the mechanism of lung damage induced by cyclohexane in rats. First, lung damage was assessed by quantifying bronchoalveolar lavage fluid (BAL) protein content as well us by histopathological examination. Second, activities of serum xanthine oxidase (XO), pulmonary XO and oxygen free radical scavenging enzymes. XO tope conversion (O/D + O, %) ratio and content of reduced glutathione (GSH) were determined. In the histopathological findings, the vasodilation, local edema and hemorrhage were demonstrated in alveoli of lung. And vascular lumens filled with lipid droplets, increased macrophages in luminal margin and increased fibroblast-like interstitial cells in interstitial space were observed in electron micrographs. The introperitoneal treatment of cyclohexane dramatically increased BAL protein by 21-fold compared with control. Cyclohexane administration to rats led to a significant rise of serum and pulmonary XO activities and O/D + O ratio by 47%,30% and 24%, respectively, compared witれ control. Furthermore, activities of pulmonary oxygen free radical scavenging enzymes such as superoxide dismutase, glutathione peroxidase and glutathione S-transferase, and GSH content were not found to be statistically different between control and cyclohexane-treated rats. These results indicate that intraperitoneal injection of cyclohexane to rats may induce the lipid embolism in pulmonary blood vessel and lead to the hypoxia with the ensuing of oxygen free radical generation, and which may be responsible for the pulmonary injury.

• Journal of Photoscience
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• 제9권2호
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• pp.150-153
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• 2002

Solar UV light is a well-known carcinogen. UVA radiation is probably carcinogenic to humans. In addition, recent investigations point to the importance of UVA irradiation in the photoaging. We investigated the mechanism of sequence- specific DNA damage using $\^$32/P-Iabeled DNA fragments in relation to carcinogenesis and aging. Furthermore, we investigated whether UVA accelerates the telomere shortening in human WI-38 fibroblasts. The exposure of double- stranded DNA fragments to 365 nm light in the presence of endogenous sensitizers produced sequence-specific cleavage at the 5' site of 5'-GG-3' and 5'-GGG-3' sequences. In addition, HPLC analysis revealed that sensitizers plus 365 nm light increased the 8-oxodG content of double-stranded DNA. We discuss the mechanisms of guanine-specific DNA damagecaused by excited photosensitizers in relation to carcinogenesis and aging.

• 대한한의학회지
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• 제21권1호
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• pp.91-98
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• 2000

The water extract of Seongpungtang(SPT) has commonly been used for treatment of ischemic brain damage in Oriental traditional medicine. However, little is known about the mechanism by which the water extract of SPT rescues brain cells from ischemic damage. To elucidate the protective mechanism of ischemic induced cytotoxicity, the regulation of Lipopolysaccharide (LPS) and PMA (phobol-12-myristate-13-acetate) induced iNOS expression in microglial cells was investigated. LPS and PMA treatment for 48 hr in microglial cells markedly induced nitric oxide (NO), but treatment of the cells with the water extract of SPT decreased nitrite formation. In addition, LPS and PMA treatment for 48 hr induced severe cell death in microglial cells. However treatment of the cells with the water extract of SPT did not induce significant changes compared to the control cells. Furthermore, NO production was markedly decreased by treatment of nuclear factor kappa B(NF-kB) inhibitor, pyrrolidine dithiocarbamate(PDTC). According to the above results, it is suggested that the protective effects of the water extract of SPT against ischemic brain damage may be mediated by regulation of iNOS during ischemic condition.

• 콘크리트학회논문집
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• 제12권3호
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• pp.67-75
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• 2000

It was well recognized that the damages associated mainly with the aging of civil infrastructures were one of very serious problems for assurance of safety and reliability. Recently carbon fiber sheet(CFS) has been widely used for reinforcement and rehabilitation of damaged concrete beam. However, the fundamental mechanism of load transfer and its load-resistant for carbon fiber sheet reinforced concrete are not fully understood. In this study, three point bending test has been carried out to understand the damage progress and the micro-failure mechanism of CFS reinforced mortars. For this purpose, four different types of specimens are used, that is, mortar, steel bar reinforced mortar, CFS reinforced mortar, and steel bar and CFS reinforced morter. Acoustic Emission(AE) technique was used to evaluate the characteristics of damage progress and the failure mechanism of specimens. in addition, two-dimensional AE source location was also performed to monitor crack initiation and propagation processes for these specimens.