• 한국지반공학회지:지반
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• 제12권6호
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• pp.65-78
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• 1996

한반도 중부지역에 위치한 청평양수발전소의 상부저수지는 준공후 16년이 경과한 사력댐으로 매일 수위 상승 및 저하를 경험하므로써, 제체의 거동이 일반 댐과는 달리 여러 가지 지반공학적 관심을 불러 일으키고 있다. 침투류에 대한 안정성을 판단하기 위하여 종래에는 심벽만을 대상으로 하여 저수지의 수위변동을 고수위 및 저수위의 두 경우로 고정시킨 정상상태의 해석을 주로 사용함에 따라 임의의 시간에서의 전체적인 침투현상 규명이 어려웠으나, 본 연구에서는 수위변동을 경계조건에 반영한 2차원 비정상류 유한요소해석을 댐 전체단면을 대상으로 수행하여 정상상태의 해석과 비교하였으며, 수위 변동에 따라 해당시간에서의 동수 경사, 침투력 벡타, 간극수압 등을 정량적으로 규명하였고, 산정된 침투수량을 계측치와 비필하였다. 그 결과 본 댐은 파이핑, 내부 침식 또는 제체 내부로의 투수 등에 대하여 안전하다고 판단된다.

• 한국지반환경공학회 논문집
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• 제13권1호
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• pp.37-43
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• 2012

일반적으로 수면과 접해 있는 호안이나 제방의 법면은 강우 침투로 인해 지반이 포화되어 침식에 약하고 유수로 인한 붕괴가 발생하기 쉽다. 따라서 사면 및 호안 제방을 축조할 경우, 비탈면 침식 및 세굴로 인해 붕괴가 발생하지 않도록 법면보호용 보강재를 설치해야 한다. 본 논문에서는 이러한 법면보호 보강재 중에서 기존의 3차원 지반보강재인 지오셀의 단점을 보완하고, 보다 친환경적인 보강재로 개발된 지오콤의 원지반과의 마찰특성, 수평투수능력, 식생의 뿌리활착 능력을 파악하기 위해 실내시험을 수행하였다. 중형전단시험 결과, 지오콤 보강지반의 내부마찰력은 기존 보강지반의 강도정수보다 증가하는 것으로 나타났고, 수평투수시험에서도 기존의 보강재보다 수평투수계수가 큰 것으로 나타났다. 이러한 결과는 셀 끝단의 구조가 기존 보강재와 달리 날카로운 돌기를 형성하고 있고, 셀의 내부표면이 망상 구조를 형성하고 있기 때문으로 판단된다.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제21권2호
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• pp.147-153
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• 2018

Epstein-Barr virus (EBV) infection can be presented with various clinical manifestations and different levels of severity when infected. Infectious mononucleosis, which is most commonly caused by EBV infection in children and adolescents, is a clinical syndrome characterized by fatigue, malaise, fever, sore throat, and generalized lymphadenopathy. But rarely, patients with infectious mononucleosis may present with gastrointestinal symptoms and complicated by gastritis, splenic infarction, and splenic rupture. We encountered a 16-year-old girl who presented with fever, fatigue, and epigastric pain. Splenic infarction and EBV-associated gastritis were diagnosed by using esophagogastroduodenoscopy and abdominal computed tomography. Endoscopy revealed a generalized hyperemic nodular lesion in the stomach, and the biopsy findings were chronic gastritis with erosion and positive in situ hybridization for EBV. As splenic infarction and acute gastritis are rare in infectious mononucleosis and are prone to be overlooked, we must consider these complications when an infectious mononucleosis patient presents with gastrointestinal symptom.

• 한국세라믹학회지
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• 제39권6호
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• pp.558-565
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• 2002

국내화력발전소의 비산재를 재활용하고자 결정화유리를 제조하여 그 물리적 특성을 평가하였다. 용융석탄재의 융점을 낮게 하기 위하여 CaO와 유리의 결정화를 유도하기 위하여 TiO$_2$를 첨가하였다. 저융점의 유리를 제조 후, 일단계 열처리 (950~105$0^{\circ}C$에서 30~240분)에 의하여 결정화유리를 제조하였다. 그 결과로, 제조된 결정화유리는 새로운 미세한 결정상(a=7.4480, b=10.2381, c=4.3940 A, $\alpha$=94.9, $\beta$=98.6, ${\gamma}$=108.5$^{\circ}$)을 갖고, 높은 경도(7.1~7.6 GPa)와 고 내마모성을 나타냈다. 이처럼 화력발전소의 비산재와 CaO의 공급원인 조개껍질로 제조된 결정화유리는 자원 재활용, 건축자재로 사용될 수 있는 새로운 응용성을 보여주었다.

• 대한치과교정학회지
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• 제23권4호
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• pp.645-660
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• 1993

In this study, effects of incision of retrodiscal tissue and unilateral occlusal reduction on temporomandibular joint of rabbit were investigated. Twenty-seven adult New Zealand White Rabbits, weighing over 3.5kg, were utilized in this study. Temporomandibular joint surgery was performed in left temporomandibular joint of 24 rabbits to displace disc anteriorly through incising the retrodiscal tissue 1-2mm posterior to the disc. They were divided into two groups : twelve were left untreated after surgery, occlusal reduction was performed on left posterior teeth every 2 weeks in the other twelve rabbits, The remaining three served as the control group. The sample were sacrificed by 8, 12, and 16 weeks after surgery. Histologic examinations were performed after sacrificing them. The results were as follows : 1. Histologic findings which were manifested by flat articular fossa, broad articular surface, generalized recession of articular cartilage and sclerosis of subchondral bone were observed. These findings were similar to internal derangement. 2. In the rabbits untreated after surgery, thin cartilagenous layer and necrotic tissue were observed in 8 weeks group, calcifying cartilagenous layer was observed in 12 weeks group, and cartilagenous layer on anterior portion was observed in 16 weeks group. So, it showed gradual healing pattern into the normal tissue except displaced disc. 3. Occlusal trauma after surgery resulted in generalized recession of upper and lower articular surface. Necrosis and vertical split on condylar process of mandible were observed in 8 weeks group. Osteoclasts, exposure of subchondral bone due to erosion on upper and lower articular surface, and degenerative changes on retrodiscal tissue were observed in 16 weeks group. So, it showed continuous prowess pattern of osteoarthrosis.

• 한국환경복원기술학회지
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• 제12권2호
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• pp.106-113
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• 2009

In this study, stability of the new gabion system with vegetation base materials was analysed. New gabion system with vegetation base materials is a new approach which has been developed to achieve lope stabilization and revegetation of forest road cut-slope by making the best use of advantages of gabion systems with vegetation base materials. Results from stability analysis are as follows. For the soil density, the angle of internal friction and unit weight of the rock fill was assumed to be $1.90g/cm^3$, $30^{\circ}$ and $2.30t/m^3$, respectively, the slope stability analysis showed that the new gabion system couldn't require any poles to fix it up, and could keep stable during both rainy and dry seasons. As the results of checks against overturning and sliding, the retaining wall with. the new gabion system could produce suitable factors of safety for overturning and sliding. Vegetation established on the surface of the new gabion systems indirectly can help to increase slope stability by prevention of surface erosion. Consequently, the new gabion system with vegetation base materials could achieve the desired effect on slope stabilization as much as existing gab ion system could do, and could promote rapid establishment of vegetation on cut-slopes.

• 대한한의학회지
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• 제28권2호통권70호
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• pp.166-184
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• 2007

Objectives : This study was conducted to investigate the effects of Daegeum-eumja, Igwi-tang, and Sihosogan-san on gastric mucosal lesions induced by alcohol, indomethacin, and burn-stress in mice. Methods : Experimental mice were divided into six groups. The normal group (NOR) did not receive any treatment to elicit gastropathy. In the control group (GE), gastropathy was elicited by alcohol, indomethacin, and stress. In the misoprostol group (MS), misoprostol was administered after gastropathy was elicited by alcohol, indomethacin, and stress. In the Daegeum-eumja group (DG), Daegeum-eumja was administered after gastropathy was elicited by alcohol, indomethacin, and stress. In the Igwi-tang group (IW), Igwi-tang was administered after gastropathy was elicited by alcohol, indomethacin, and stress. In the Sihosogan-san group (SH), Sihosogan-san was administered after gastropathy waselicited by alcohol, indomethacin, and stress. The effects on gastric mucosal lesions were evaluated by the morphological change of gastric mucosa, the anti-oxidant effect, HSP 70, $NF-{\kappa}B$ p65, $I{\kappa}B$, COX-1, PNA, BrdU, and iNOS. Results : Hemorrhage erosion, HSP70, and $NF-{\kappa}B$ in the DG, IW and SH groups decreased more than that of the control. The $I{\kappa}B$, COX-1, PNA, BrdU, and iNOS in the DG, IW, and SH groups increased more than that of the control. DG showed the most effect against gastric mucosal lesions induced by alcohol; IW against gastric mucosal lesions induced by indomethacin; and SH against gastric mucosal lesions induced by burn-stress. Conclusions: Daegeum-eumja, Igwi-tang, and Sihosogan-san extracts have excellent effects on gastric mucosal lesions induced by alcohol, indomethacin, and burn-stress, respectively.

• Tribology and Lubricants
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• 제28권6호
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• pp.315-320
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• 2012

For proper functioning, general machines usually need lubricant oil as a cooling, cleaning, and sealing agent at points of mechanical contact. The quality of lubricant oil can deteriorate during operation owing to various causes such as high temperature, combustion products and extraneous impurities. In this study, a heavy load stopped during operation, and the oil was analyzed to check whether any impurities were added. Extraction using acetonitrile followed by reaction with BSTFA(bistrimethylsilyl trifluoroacetamide) showed that, trimethylsilylated ethylene glycol was present in the lubricant oil. To quantify the ethylene glycol in the oil, deuterium-substituted ethylene glycol, which acted as an internal standard, was added to the sample and then extracted with the solvent. Next, the extract was reacted with the derivatizing agent(BSTFA) and then analyzed with GC/MS. The detection limit of this method was found to be $0.5{\mu}g/g$ and the recovery of oil containing $20,000{\mu}g/g$ of ethylene glycol was measured to be 94.8%. A damaged O-ring and eroded cylinder liner were found during the overhaul, which implied the leakage of coolant containing ethylene glycol into the lubricating system. The erosion of the cylinder liner was assumed to be due to cavitation of the coolant in the cooling system.

• Journal of Welding and Joining
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• 제28권1호
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• pp.66-71
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• 2010

With large specific strength and outstanding corrosion resistance and erosion resistance in sea water, titanium and titanium alloy are widely used in heat exchanger production. In particular, pure titanium demonstrates outstanding molding performance and may be considered optimal for production of heat exchanger. Since titanium is very vulnerable to oxidation and embrittlement during welding, processes with less heat input are widely used, and laser welding is widely applied by considering production performance and shield etc in atmosphere. So far, 1st report and 2nd report compared and analyzed embrittlement degrees by bead colors of weldment through oxygen and nitrogen quantitative analysis and hardness measurement, and evaluated welding performance and mechanical properties of butt welding. This study evaluated field applicability of lap welding to heat exchange plate of LPG re-liquefaction device for ships through tensile stress test, hardness test and internal pressure test etc after deducing optimal weding condition and applying to actual heat exchange plate. In bead overlap area, the experiment produced sound welds with no porosity or defect by increasing and decreasing laser power, and tensile-shear test results indicated virtually the same tension and yield strength as base metal. As a result of measuring hardness at lateral cross section and bead overlap zone of actual heat exchanger welds, hardness difference within 20Hv was produced at base metal, HAZ and weldment, and as a result of pneumatic and hydraulic pressure test, no leakage occurred.

• 한국정보기술학회논문지
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• 제15권12호
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• pp.165-171
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• 2017

본 논문은 서포터 생성 기법으로 형태학적 기하학 연산을 대신하여 층 단면 영상에 형태학적 영상 처리를 적용함으로 서포터를 생성하는 방법을 제안하였다. 기하학적 연산 비용은 일반적으로 형태에 의존적이지만 본 방법은 영상 내의 형태에 무관하게 적용된다. 돌출부에 대한 외부 서포터 영역을 얻는 방법으로 2개의 층 단면 영상에 대한 형태학적 영상 처리 방법 및 처리 과정의 예를 보였다. 내부 서포터 영역에 대하여 하나의 층 단면으로부터 침식과 열림을 통해 얻는 과정을 나타내었다. 그리고 이러한 서포터 영역을 얻고 서포터 구조를 통한 서포터를 생성하였다. 이어서 제작한 DLP 프린터에 서포터 구조를 가진 조형물을 제작하였다. 또, 서포터 형태에 따라 조형되는 소재의 특성이 조형에 주는 변화를 통해 소재에 따른 개별적인 서포터 구조를 통한 서포터 생성 방법의 필요성을 확인하였다.