• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2006년 추계학술발표대회 개요집
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• pp.26-28
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• 2006

When materials such as metal are into the secondary side of steam generator, they, so called foreign objects, may have influences on the integrity of the steam generator tubes. They cause the tube wear due to the relative motion between the tubes and foreign objects and the tube impact due to flow. The best way to avoid the effects is to remove all the foreign objects. However, it is not easy to remove the foreign materials thoroughly due to their condition such as the location. Considering the wear and impact by the foreign materials, KEPRI(Korea Electric Power Research Institute) developed the methodology to evaluate the foreign materials analytically. This methodology was described with a computer program in order to obtain the fast results. The program informs whether the tubes have the structural integrity when the foreign material strikes the tubes. Moreover, this gives us the remaining life of the steam generator tubes. In this paper, the program, which evaluates the effects of the foreign objects in the secondary side of steam generator, is introduced.

• 제어로봇시스템학회논문지
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• 제20권9호
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• pp.964-970
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• 2014

In this study we have developed an anthropomorphic robot hand and arm by using tendon-tubes which can be used for people's everyday life as a robot's dynamic power transmission device. Most previous robot hands or arms had critical problem on dynamic optimization due to heavy weight of power transmission parts which placed on robot's finger area or arm area. In order to resolve this problem we designed light-weighted robot hand and arm by using tendon-tubes which were consisted of many articulations and links just like human's hand and arm. The most prominent property of this robot hand and arm is reduction of the weight of robot's power transmission part. Reduction of weight of robot's power transmission parts will allow us to develop energy saving and past moving robot hands and arms which can be used for artificial arms. As a first step for real development in this study we showed structural design and demonstration of simulation of possibility of a robot hand and arm by tendon-tube. In the future research we are planning to verify practicality of the robot hand and arm by applying sensing and controlling method to a specimen.

• 한국정밀공학회지
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• 제30권9호
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• pp.969-975
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• 2013

As energy shortage is getting more serious, wind energy source is more promoted around the world. Blade is a key component of wind turbine. Local breakages and/or contamination in the blade bring degradation in aerodynamic efficiency and life-time. However, it is not easy and even dangerous for human workers to access the blade for inspection and maintenance since its size is huge and located at high mountains and rough sea, which are windy places. This paper deals with a novel moving mechanism that efficiently carries human workers or robots to the wind turbine blade. The proposed mechanism utilizes flexible tube with pressurized air that rolls and climbs over the blade surface. So, the tube naturally adapts the changing surface of the blade and acts no harm to it. This paper discusses about its concept, detail design, and advantages. The feasibility of the proposed mechanism is proved through experiments prototype.

• Smart Structures and Systems
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• 제19권4호
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• pp.371-382
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• 2017

Concrete filled steel tubes are extensively applied in engineering structures due to their resistance to high tensile and compressive load and convenience in construction. But one major flaw, their vulnerability to environmental attack, can severely reduce the strength and life of these structures. Degradation due to corrosion of steel confining the concrete is one of the major durability problems faced by civil engineers to maintain these structures. The problem accelerates as inner surface of steel tube is in contact with concrete which serves as electrolyte. If it remains unnoticed, it further accelerates and can be catastrophic. This paper discusses a non-destructive degradation monitoring technique for early detection corrosion in steel tubes in CFST members. Due to corrosion, damage in the form of debonding and pitting occurs in steel sections. Guided ultrasonic waves have been used as a feasible and attractive solution for the detection and monitoring of corrosion damages in CFST sections. Guided waves have been utilized to monitor the effect of notch and debond defects in concrete filled steel tubes simulating pitting and delamination of steel tubes from surrounding concrete caused by corrosion. Pulse transmission has been used to monitor the healthy and simulated damaged specimens. A methodology is developed and successfully applied for the monitoring of concrete filled steel tubular sections undergoing accelerated chloride corrosion. The ultrasonic signals efficiently narrate the state of steel tube undergoing corrosion.

• 한국군사과학기술학회지
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• 제14권4호
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• pp.615-621
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• 2011

In this paper, the proper quantity of conditioning rounds has been studied using the statistical analysis on the basis of the acceptance test data of K676 and K677 propelling charge for K9 self propelled howitzer. In general, the muzzle velocity of the initial rounds tends to be a little lower than that of the succeeding rounds. The latter rounds are likely to have the constant velocities after firing the appropriate conditioning rounds. The main cause of velocity difference was proved to be the proper quantity of conditioning rounds by doing the correlation analysis among the initial tube temperature, the tube life and the quantity of conditioning rounds. The result of paired t-test shows that two rounds of conditioning projectiles are proved to be enough to maintain the constant velocity in the case of the acceptance test of K676 and K677 propelling charge.

• Fisheries and Aquatic Sciences
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• 제17권3호
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• pp.305-311
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• 2014

Dieckol is a polyphenol compound isolated from brown algae that has anti-oxidant, anti-inflammatory, and anti-tumor activity. We examined the anti-angiogenic effects of dieckol in endothelial cells under hypoxic conditions. Treatment with $CoCl_2$, a hypoxic mimetic agent, increased proliferation, adhesion, migration, and tube formation in HUVECs, as well as vessel sprouting in rat aortic rings, which correlated well with increased expression of hypoxia-inducible factor 1-alpha ($HIF1{\alpha}$) and ${\beta}1$-integrin. Dieckol suppressed $CoCl_2$-induced adhesion, migration, and tube formation in HUVECs and vessel sprouting in rat aortic rings. Dieckol treatment decreased $CoCl_2$-induced overexpression of $HIF1{\alpha}$ and its downstream signaling molecules, including ${\beta}1$-integrin/Fak, Akt/eNOS, and p38 MAPK. These results suggest that dieckol is a novel angiogenesis inhibitor and a potential treatment for angiogenesis-dependent diseases in humans, such as malignant tumors.

• Journal of Chest Surgery
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• 제29권6호
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• pp.672-674
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• 1996

유미흉은드물지만 심장수술,횡격막의 식도,대동맥 열공 부위의 수술합병증으로잘알려졌다. 특히 식도의 양성 또는 악성 종양에서 식도제거술이 필요한 영양 결핍상태의 환자에서 유미흥은호흘기능, 영양상태, 면역학적 인 면에서 치사율이 높은 위 험한 질병 이다. 본교실에서는 식도헙착 환자에서 식도열공을 통한 식도 제거술후 발생한 유미흥 1례를 경험하였다. 유미홍의 진단은 공장루를 통한 영양공급후 흥막 삼출액의 변화와 술후 5일째 흉막액의 Triglyceride 치의 증가로 진단하였다. 금식 상태에서도 하루 1500내지 2000cc의 유미삼출액이 배액되어 13일째 우 측 개흉술을 통해 횡격막 상부 흉관 결찰을 시 행하였으며, 좋은 결과를 얻을 수 있었다.

• 한국항공우주학회지
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• 제40권3호
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• pp.237-242
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• 2012

극저온이 요구되는 우주용 탑재장비의 냉각을 위해 일반적으로 Pulse Tube-type 압축기가 적용되고 있으며, 궤도상에서 압축기의 냉각성능, 임무수명 및 비대칭 온도분포에 의한 미소진동발생 방지를 위해 압축기를 허용온도 범위로 유지하는 열제어가 필요하다. 압축기는 궤도 운용 시 미소진동을 발생하여 관측성능이 요구되는 탑재체의 지향성능을 저하시키는 원인으로 작용한다. 본 논문에서는 압축기의 미소진동 방지를 목적으로 적용된 진동절연기의 성능유지 및 압축기의 허용온도범위 유지를 위한 열제어 성능을 동시에 만족하는 우주용 압축기 조립체의 열설계를 제안하였으며, 설계의 유효성을 해석적으로 입증하였다.

• Journal of Medicine and Life Science
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• 제17권1호
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• pp.25-28
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• 2020

The prevalence of pulmonary pargonimiasis in Korea has been steadily decreasing due to develop of the public health, and there have been few clinical cases of paragonimiasis infections, especially in pneumothorax. A 22-year-old man referred to emergency department for dyspnea and chest pain. The right lung was totally collapsed on a chest X-ray. We emergently performed a closed thoracostomy with a 28-Fr chest tube. However, the air leak from the chest tube persisted for three days after the closed thoracostomy. A chest computed tomography showed multiple subpleural consolidative nodular lesions and mixed ground-glass attenuation nodules. We potentially suspected a secondary pneumothorax resulting from pulmonary paragonimiasis infection because the patient was a Chinese man who was working at a Korean restaurant. We decided to perform a medical treatment instead of pulmonary wedge resections. The air leak was discontinued three days after the prescription of praziquantel. The patient was discharged nine days after the admission. We suggest that anti-parasitic drugs are very effective in the secondary pneumothorax resulting from paragonimiasis.

• Molecules and Cells
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• 제39권4호
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• pp.292-298
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• 2016

Aquaporin 1 (AQP1) is expressed in most microvasculature endothelial cells and forms water channels that play major roles in a variety of physiologic processes. This study aimed to delineate the transcriptional regulation of AQP1 by Mef2c in endothelial cells. Mef2c cooperated with Sp1 to activate human AQP1 transcription by binding to its proximal promoter in human umbilical cord vein endothelial cells (HUVEC). Over-expression of Mef2c, Sp1, or Mef2c/Sp1 increased HUVEC migration and tube-forming ability, which can be abolished AQP1 knockdown. These data indicate that AQP1 is a direct target of Mef2c in regulating angiogenesis and vasculogenesis of endothelial cells.