• 한국도로학회논문집
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• 제19권6호
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• pp.105-115
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• 2017

PURPOSES : The occurrence of unexpected disasters, including fire events, increases as the road network becomes complicated and traffic volume increases. When a fire event occurs on and under bridges, the damage extensively influences direct damage to structures, vehicles, and human life and secondary socioeconomic issues owing to traffic blockage. This study investigated potential fire-hazard risks on bridges of the Korean national route road. METHODS : The investigation was conducted using field investigation and analysis with satellite pictures and road views from commercial websites and the Bridge Management System (BMS). From the filed investigation, various potential fire resources were identified. The satellite pictures and road views were helpful in measuring and recognizing conditions underneath bridges, stowage areas, etc. RESULTS : There are various potential fire resources underneath bridges such as piled agricultural products, parked petroleum tanks, construction equipment, and attached high-voltage cables. A total of 94.6% of bridges have underneath clearances of less than 15 m. A bridge underneath volume that can stow a potential fire hazard resource was $7,332m^3$ on average, and most bridges have about $4,000m^3$ of space. Based on the BMS data, the amounts of PSC and steel girders were 29% and 25%, respectively. CONCLUSIONS : It was found that the amount of stowed potential fire hazard resources was proportional to the underneath space of bridges. Most bridges have less than 15 m of vertical clearance that can be considered as a critical value for a bridge fire. The fire risk investigation results should be helpful for developing bridge fire-protection tools.

• 사상체질의학회지
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• 제13권2호
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• pp.165-176
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• 2001

This study demonstrates the effects of Yanggyuksanhwa-Tang, Sasang constitutional herb prescription reported its clinical effect on the stroke of the So-yang In(少陽人), on the cerebral blood flow changes induced by nitro L-arginine methyl ester (L-NAME) treatment and ischemic brain damage induced by the middle cerebral artery occlusion (MCAO) in the rats. The changes of the arterial blood pressure, cerebral blood flow, and the diameter of the pial artery were measured in rats treated with L-NAME. And the changes of the infarct size, volume, and plasma tumor necrosis factor alpha ($TNF-{\alpha}$) levels were measured in the rats that the middle cerebral artery has been occluded by the intraluminal suture thread method. Yanggyuksanhwa-Tang was administered by the i.v. injection on the L-NAME treated rats, by the i.o. administration on the MCAO rats. The results is 1. The changes of the arterial blood pressure was not different statistically between in the L-NAME treated control group and in the Yanggyuksanhwa-Tang administered group. 2. Increase in the cerebral blood flow induced by L-NAME treatment was attenuated in the Yanggyuksanhwa-Tang administered group significantly (P<0.05) as compared with the L-NAME treated control group. 3. Decrease in the diameter of the pial artery induced by L-NAME treatment was attenuated about 18% in the Yanggyuksanhwa-Tang administered group as compared with the L-NAME treated control group. 4. Ischemic damaged infarct areas were decreased significantly (P<0.05) in the interaural 12mm, 10mm, and 6mm brain sections of the Yanggyuksanhwa-Tang administered group as compared the MCA occluded control group. 5. Total ischemic infarct volume was decreased significantly (P<0.05) in the Yanggyuksanhwa-Tang administered group as compared the MCA occluded control group. 6. Plasma $TNF-{\alpha}$ levels were decreased significantly (P<0.01) in the Yanggyuksanhwa-Tang administered group as compared the MCA occluded control group.

• Clinical and Experimental Pediatrics
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• 제64권8호
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• pp.422-429
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• 2021

Background: Carnosine has antioxidative and neuroprotective properties against hypoxic-ischemic (HI) brain injury. Hypothermia is used as a therapeutic tool for HI encephalopathy in newborn infants with perinatal asphyxia. However, the combined effects of these therapies are unknown. Purpose: Here we investigated the effects of combined carnosine and hypothermia therapy on HI brain injury in neonatal rats. Methods: Postnatal day 7 (P7) rats were subjected to HI brain injury and randomly assigned to 4 groups: vehicle; carnosine alone; vehicle and hypothermia; and carnosine and hypothermia. Carnosine (250 mg/kg) was intraperitoneally administered at 3 points: immediately following HI injury, 24 hours later, and 48 hours later. Hypothermia was performed by placing the rats in a chamber maintained at 27℃ for 3 hours to induce whole-body cooling. Sham-treated rats were also included as a normal control. The rats were euthanized for experiments at P10, P14, and P35. Histological and morphological analyses, in situ zymography, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assays, and immunofluorescence studies were conducted to investigate the neuroprotective effects of the various interventional treatments. Results: Vehicle-treated P10 rats with HI injury showed an increased infarct volume compared to sham-treated rats during the triphenyltetrazolium chloride staining study. Hematoxylin and eosin staining revealed that vehicle-treated P35 rats with HI injury had decreased brain volume in the affected hemisphere. Compared to the vehicle group, carnosine and hypothermia alone did not result in any protective effects against HI brain injury. However, a combination of carnosine and hypothermia effectively reduced the extent of brain damage. The results of in situ zymography, TUNEL assays, and immunofluorescence studies showed that neuroprotective effects were achieved with combination therapy only. Conclusion: Carnosine and hypothermia may have synergistic neuroprotective effects against brain damage following HI injury.

• 생명과학회지
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• 제31권2호
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• pp.137-143
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• 2021

근육 위축증은 근섬유의 손상으로 인한 근육세포의 감소에 의해 일어나며 심장질환, 당뇨, 각종 노인성 만성질환을 일으킨다고 알려져 있다. 본 연구는 미역 추출물 및 이의 성분인 알긴산의 근육세포보호, 근육감소억제 및 근육재생효과를 확인하고자 하였다. 미역 추출물 및 알긴산을 분화된 C2C12 myoblast 세포에 처리한 결과 TNF-α에 의한 근육섬유의 감소가 억제하였고murf1과 MaFbx의 발현량도 감소하였다. 또한, 마우스에 미역 추출물 및 알긴산을 10주간 급여한 결과 cardiotoxin에 의한 다리부종이 감소하였으며 근육단백질인 MyHC와 PGC-1α의 발현량이 증가 하였다. 따라서 미역 추출물 및 알긴산은 근감소 억제 및 근육재생 효과를 나타내어 기능성소재의 활용 가능성을 확인하였다.

• 한국안전학회지
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• 제36권4호
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• pp.71-79
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• 2021

In this study, a real-scale fuel-cell room of volume 1.36 m³ is constructed to confirm the explosion characteristics of hydrogen-air mixture gas in a hydrogen-powered house. A volume concentration of 40% is applied in the fuel-cell room as the worst-case scenario to examine the most severe accident possible, and two types of doors (made of plastic sheet and wood) are fabricated to observe their effects on the overpressure and impulse. The peak overpressure and impulse based on distance from the ignition source are experimentally observed and assessed. The maximum and minimum overpressures with a plastic-sheet door are about 20 and 6.7 kPa and those with a wooden door are about 46 and 13 kPa at distances of 1 and 5 m from the ignition source, respectively. The ranges of impulses for distances of 1-5 m from the ignition source are about 82-28 Pa·s with a plastic-sheet door and 101-28 Pa·s with a wooden door. The amount of damage to people, buildings, and property due to the peak overpressure and impulse is presented to determine the safe distance; accordingly, the safe distance to prevent harm to humans is about 5 m based on the 'injuries' class, but the structural damage was not serious.

• Journal of Acupuncture Research
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• 제21권4호
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• pp.207-215
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• 2004

Objective : In order to prove the effect of Hirudin Herbal-acupuncture this experimental studies were performed by using rats that had neuronal damage due to the Middle Cerebral Artery Occulsion(MCAO). Methods : Microdialysis probes were implanted into the coordinate of striatum of anesthetized rats which consist of sham-operated 8 rats, MCAO-operated 8 rats and Hirudin Herbal-acupuncture administrated 8 rats before MCAO operating. The Hirudin Herbal-acupuncture(0.5mg/kg) was administrated to rats 30 minutes before having an operation causing the MCAO. The surgical excision lead the cross resected brain to the acute ischemic state. The brain was sliced in 2mm thickness and stained with cresyl violet buffer for the measurement of cerebral infarcted area and volume. Results : Based on the result of the tissue inspection for the cerebral ischemic cell, Hirudin Herbal-acupuncture significantly protect neurocytes. Conclusion : We suggest Hirudin Herbal-acupuncture produces protective effects against the neuronal damage induced by MCAO. Therefore, Hirudin Herbal-acupuncture may prevent delayed neuronal death(DND) in selectively vulnerable focal areas of the brain effectively.

• 한국터널지하공간학회 논문집
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• 제9권3호
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• pp.299-307
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• 2007

본 논문에서는 터널 숏크리트 라이닝의 장기 화학적 열화에 의한 물리적 손상을 수치적으로 모델링하기 위한 새로운 개념의 해석기법이 제안되었다. 이러한 물리적 손상은 내부균열 발생, 재료 강성과 강도의 저하에 의해 주로 유발되며, 이들은 장기 화학적 열화반응에 의한 체적팽창 및 시멘트질의 침식에 의해 발생된다. 결과적으로, 이러한 숏크리트 라이닝의 손상 메카니즘은 터널내에서 발생할 수 있는 다양한 종류의 열화반응들에서 유사하게 나타난다. 따라서, 본 연구에서는 일련의 화학적 열화 반응에 기인한 물리적 손상 메카니즘을 일반화 하였으며, 열역학에 기반한 수치모델을 수학적으로 유도 하였다. 유도된 수치모델은 3차원 유한요소 프로그램으로 코드화되었으며, 외력과 장기 화학적 열화를 겪고 있는 터널 구조물의 시간의존성 거동 시뮬레이션에 적용된다. 개발된 코드는 몇 개의 예제 수행을 통해 터널설계상에서의 적용성을 검토하였으며, 동일한 열화조건하에서도 주변 지반응력상태에 따라 물리적 손상 속도와 정도가 크게 달라짐을 보였다.

• 한국방재학회 논문집
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• 제7권4호
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• pp.59-66
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• 2007

하천을 횡단하는 교량은 하천의 배수위를 증가시키는 중요한 요인으로 작용한다. 더욱이 산지하천에 시공된 교량은 유송잡물에 의한 폐색으로 인하여 교량 직상류부에 홍수피해를 가중시킨다. 본 연구에서는 교각에 집적되는 유송잡물의 영향으로 인해 발생할 수 있는 홍수피해 규모를 확인하고자 대상하천에 대한 HEC-RAS 모형과 HEC-GeoRAS 모형을 구축하여 모의하였다. 교각에 집적된 유송잡물에 의한 폐색이 하천의 범람을 일으키는 원인으로 가정하여 범람 시나리오 별로 부정류 모의를 실시한 결과 월류지점 및 홍수용량을 산정하였고, 이에 따라 대략적인 범람예상구역을 작성하였다. 그러나 범람구역의 침수면적과 침수심에 대하여 실제 분석결과를 제대로 반영하지 못하는 한계가 있었다. 따라서 수치지형도와 위성사진을 이용하여 범람예상구역을 재설정하고 수치고도자료 내에서 월류용량과 동일 용량의 침수면적과 침수심을 갖는 범람구역을 재작성하는 과정을 수행함으로써 좀 더 정확한 홍수피해 규모를 산정하였다.

• 대한기계학회논문집A
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• 제26권9호
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• pp.1787-1794
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• 2002

TiNi alloy fiber was used to solve the problem of the tensile residual stress as the reinforced material. TiNi alloy fiber improves the tensile strength of composite by occurring compressive residual stress in the matrix using shape memory effect. In order to generate compressive residual stress in TiNi/Al6061 shape memory alloy(SMA) composite, 1, 3 and 5% pre-strains were applied to the composite in advance. It was also evaluated the effect of compressive residual stress corresponding to the pre-strain variation and the volume fraction of TiNi alloy. AE technique was used to clarify the microscopic damage behavior at high temperature and the effect of pre-strain in TiNi/Al6061 SMA composite. The results of the microscopic damage evaluation of TiNi/Al6061 SMA composite under various pre-strain using AE technique can be divided into three stage corresponding to the AE signals. AE counts and events were useful parameters to evaluate the fracture mechanism according to the variation of pre-strain. In addition, two dimensional AE source location technique was applied for monitoring the crack initiation and propagation in composite.

• Korean Journal of Acupuncture
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• 제21권3호
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• pp.89-96
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• 2004

Objectives : In order to prove the effect of Phospholipase $A_2(PLA_2)$ Herbal-acupuncture, this experimental studies were performed by using rats that had neuronal damage due to the Middle Cerebral Artery Occulsion(MCAO). Methods : Microdialysis probes were implanted into the coordinate of striatum of anesthetized rats which consist of sham-operated 8 rats, MCAO-operated 8 rats and $PLA_2$ Herbal-acupuncture administrated 8 rats before MCAO operating. The $PLA_2$ Herbal-acupuncture(0.5mg/kg) was administrated to rats 30 minutes before having an operation causing the MCAO. The surgical excision lead the cross resected brain to the acute ischemic state. The brain was sliced in 2mm thickness and stained with cresyl violet buffer for the measurement of cerebral infarcted area and volume. Results : Based on the result of the tissue inspection for the cerebral ischemic cell, $PLA_2$ Herbal-acupuncture significantly protect neurocytes. Conclusions : We suggest $PLA_2$ Herbal-acupuncture produces protective effects against the neuronal damage induced by MCAO. Therefore, $PLA_2$ Herbal-acupuncture may prevent delayed neuronal death(DND) in selectively vulnerable focal areas of the brain effectively.