• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1541-1548
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• 2015

In this study, strengthening methods of floor surface finishing mortar are investigated to prevent the cracks using crack inhibitor agents, water reducer agent and resin. As a results, The number of crack and compressive strength of the specimen containing water reducer agent or resin had more effective than other specimens containing inhibitor agents at 7 days. And the highest compressive strength specimen showed the relatively no crack, but the lowest compressive strength specimen showed a lot of crack. Therefore the relationship between the crack growth and the compressive strength had proportional connection. A base on the mock-up test, long-term monitoring of the on-site applied to mixing design type3 showed the few cracks.

• Journal of Korea Water Resources Association
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• v.40 no.3
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• pp.215-221
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• 2007

The main purpose of this study is to find the appropriate method to prevent the reduction of infiltration capacity due to sealing of soil surface. The study results indicate that installation of gravel or larger soil facilitates the drainage of infiltrated rainwater. However, considering that the infiltration capacity has been reduced since the installation, it seems that the sealing of soil surface is caused by the inflow of suspended soil into the lower sand layer. To promote the infiltration capacity by reducing the pounding of lower natural soil layer, the sand soil should be placed above the natural soil layer with shallow depth just below the larger gravel. Furthermore, the crust generated above the soil surface should be removed regularly and the sand layer above the natural soil layer should be replaced with new one so that the original infiltration capacity can be maintained properly.

• Tuberculosis and Respiratory Diseases
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• v.40 no.4
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• pp.390-394
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• 1993

Background: Bronchiectasis is characterized by chronic sputum production and complications such as hemoptysis and repeated infections. Even though some patients are cured by surgical resection of bronchiectatic lesions, most bronchiectasis patients can not be treated surgically because of multiple site involvement, and they are treated by medical measures such as postura1 drainage and antibiotics when indicated. Recently there have been some reports that low-dose longterm erythromycin treatment is effective on bronchiectsis, and it is well known that low-dose longterm erythromycin treatment is the treatment of choice in diffuse panbronchiolitis which is characterized by chronic sputum production and dyspnea. To evaluate the efficacy of erythromycin, we tried erythromycin on twenty five stable bronchiectasis patients for more than six months. Methods: We tried erythromycin 250 mg b.i.d. for more than 6 months. We checked respiratory symptoms, chest PA, spirometry, and side effects before treatment and after 3 and 6 months of treatment. Results: 1) 32% of the patients showed marked improvement of symptoms and PFT. 32% showed slight improvement of symptoms with little change of PFT, and 36% showed no change of symptoms and signs. 2) Analysis of the patients showing marked improvement revealed that most of them had diffuse bronchiectasis and paranasal sinus involvement. Conclusion: These results suggest that low-dose longterm erythromycin treatment can be tried on diffuse bronchiectasis patients with sinus involvement. And further studies will be followed on the mechanism of erythromycin in bronchiectasis.

• Journal of Veterinary Clinics
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• v.15 no.2
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• pp.370-377
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• 1998

본 연구는 황색포도상구균의 병원성 인자인 alpha-toxin, casular polysaccharides (CPS)와 fibronectin-binding protein (FnBP)을 이용해 실험동물인 토끼에서의 항체가 형성 능과 공격접종 후 방어능에 관한 연구를 위하여 수행되었으며 향후 젖소 유방염 아단위 항원 을 이용한 백신개발 가능성을 탐색하고자 수행되어졌다. 황색포도상구균의 alpha-toxin, capsu18r polysaccharides (CPS)91 fibronectin-binding protein (FnBP) 항원을 이통재 효소면 역측정법을 통한 혈중 IgG 항체가수준을 측정하였으며 alpha-toxin, capsular polysaccharides (CPS)와 fibronectin-binding protein (FnBP)으로 면역시킨 토끼에서 대조군의 토끼보다 혈 중 항체가 수준이 1차 면역 이후 유의성 있게 높았다 (p<0.05). 백신에 사용된 alpha-toxin, capsular polysaccharides (CPS)와 fibronectin-binding protein (FnBP) 항원중 capsular polysaccharides (CPS)가 다른 alpha toxin과 fibronectin-binding protein (FnBP)의 혈중항 체가 수준과 비교하여 볼 때 비교적 낮은 수준이었다. 세균을 혈중으로 공격접종한 후 대조군 과 백신접종군의 혈중내 세균제거율에 있어 대조군에 비해 백신접종군에서 유의성 있게 낮은 균수를 보였다 (p<0.05). 또한 장기내 균수측정실험결과 대조군의 장기보다 백신접종군에서 유의성 있게 세균수가 낮게 출현하였다 (p<0.05). 결론적으로 본 연구결과 황색포도상구균의 3가지 항훤 alpha-toxin, capsular polysaccharide와 재조합 fibronectin binding protein을 이 퐁한 실험동물에서 안단위 유방염 백신은 방어능이 있다고 생각된다.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.27 no.2
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• pp.75-81
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• 2018

The aim of this study was to evaluate the biomechanical behavior and long-term safety of high performance polymer PEKK as an intraradicular dental post-core material through comparative finite element analysis (FEA) with other conventional post-core materials. A 3D FEA model of a maxillary central incisor was constructed. A cyclic loading force of 50 N was applied at an angle of $45^{\circ}$ to the longitudinal axis of the tooth at the palatal surface of the crown. For comparison with traditionally used post-core materials, three materials (gold, fiberglass, and PEKK) were simulated to determine their post-core properties. PEKK, with a lower elastic modulus than root dentin, showed comparably high failure resistance and a more favorable stress distribution than conventional post-core material. However, the PEKK post-core system showed a higher probability of debonding and crown failure under long-term cyclic loading than the metal or fiberglass post-core systems.

• KSBB Journal
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• v.11 no.4
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• pp.453-461
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• 1996

We compared the effects of two different systems of collagen matrix protein application on the survival and the biological functions of cultured primary hepatocytes. The rat liver primary hepatocytes were grown for approximately 40 days in vitro either on single collagen gel or between collagen sandwich gels. The morphological changes were observed for this culture period. While the hepatocytes grown on single gel began to die around at 7 days of culture, the cells grown between collagen gels still maintained their viability and began to die after 15 days. As markers for liver hepatic functions, we determined the biochemical activities of hepatocytes such as the secretions of albumin, fibronectin, fibrinogen, urea, and the reduction of secreted ammonia. We found that the rat hepatocytes cultured between collagen gels maintained fairly good biochemical functions than the hepatocytes cultured on single gel did. Therefore, the application of an extracellular matrix protein, collagen, in sandwich form was confirmed as a better choice for maintaining the functional hepatocytes culture for long term in vitro.

• Tuberculosis and Respiratory Diseases
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• v.43 no.4
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• pp.491-499
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• 1996

Background : Pleural effusion is a common disease in clinical practice but its effect on pulmonary function and altered pulmonary mechanics after removal of effusion are not still largely understood. Previous studies have shown that there is little or a relatively small improvement in pulmonary function and arterial blood oxygenation after therapeutic thoracentesis. The present study was designed to assess the effect on pulmonary function of pleural effusion and to test whether there was a significant improvement in pulmonary function and arterial oxygenation after thoracentesis and to observe long tenn effect after thoracentesis. Method : We examined flow-volume curve, body box and arterial blood gas analysis according to severity of effusion, present symptom, and symptom duration. Then, we measured changes of pulmonary function after thoracentesis and observed longterm effect after thoracentesis. Result: 1) Pleural effusion cause restrictive pulmonary insufficiency. Not only functional impairment of small airway but also large airway is provoked. 2) MMFR, FEV1, Raw, POz are earlier improved than FVC and TLC after thoracentesis and patients without complication have mild restrictive pulmonary insufficiency after longterm observation. 3) FVC, FEV1, & TLC are similarly restricted as severity of pleural effusion and po, is relatively decreased. 4) Cases with symptom duration 1 week or less and cases with dyspnea have more severe pulmonary insufficiency than others. 5) The flow volume curves show a relatively greater improvement in flow rates at large lung volumes than small airway. 6) Significant relationship is shown between first thoracentesis amount and changes of FEV1, FVC, TLC. Conclusion: Pleural effusion cause restrictive pulmonary insufficiency and not only functional impairment of small airway impairment but also large airway is provoked. Then, Pulmonary function is progressively improved after thoracentesis and remained mild restrictive pulmonary insufficiency after recovery.

• Magazine of the Korean Society of Agricultural Engineers
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• v.28 no.2
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• pp.74-86
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• 1986

유동화콘크리트의 공학적 특성에서 시간-의존거동을 확인하기 위하여,나프타렌 설폰산염 폴리머 고축합물인 Rheobuild 1000과 메라민 설폰산염 고축합물인 NP-20의 고성능감수제를 사용한 유동화콘크리트와 보통콘크리트를 제조하여 비교.고찰을 행하였으며, 고성능감수제의 종류 및 함량이 콘크리트의 공학적 특성에 미치는 영향을 구명하기 위하여 재령 3일, 14일, 28일, 60일, 90일, 180일의 압축강도를 측정, 조기 및 장기압축강도를 조사하였고, 인장강도 및 탄성 변형에 미치는 영향을 조사하였다. 또한 습윤 및 에어콘디션의 양생조건하에서 시간의 경과에 따른 건조수축 및 크리이프 변형을 조사.분석함으로써 유동화콘크리트의 시간-의존거동을 확인하였다. 실험결과, 사용 고성능 감수제의 종류에 따라 차이는 있으나, 고성능 감수제의 사용은 일반적으로 워커빌리티 성능을 개선하고 압축 및 인장도를 크게 향상시키며, 탄성계수는 보통의 콘크리트에 비하여 높게 나타났다. 또한 건조수축 및 크리프 변형의 감소에 매우 양호한 결과를 나타내어 앞으로 건설용 용도로써 효과적인 것으로 판단되었다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.93-96
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• 2008

This research performed strength improvement analysis after evaluating strength characteristics by estimated temperatures to evaluate the real time strength performance of 50 to 80 MPa high performance concrete equipped with heat resistance, and the results are as follows. The lesser W/B and the lesser target slump flow value difference, compression strength was shown to increase, and the more curing temperature becomes, the strength increased accordingly. According to the correlation review result of strength improvement analysis by estimated temperature change performed using logistic analysis model, the compression strength value predicted with logistic curve expression and the compression strength value measured in experiment were shown to have similar correlation, and the strength improvement analysis value by logistic model was shown to be estimated good when W/B is high.

• Journal of the Korean Solar Energy Society
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• v.22 no.3
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• pp.77-87
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• 2002

그 열흐름의 방향이 인위적으로 조절 가능한 열다이오드 시스템에 관하여 일차원적 열전달 모델을 통하여 시스템의 열성능을 분석하였다. 열다이오드 시스템은 다수의 폐회로 유체 순환 루프로 구성되었으며 루프의 양단은 각각 태양열 흡열판과 방열판에 부착되었다. 한편, 열흐름의 방향 조절을 위하여 루프를 구성하는 튜브재의 연결 부위는 회전 가능한 조인트로 연결하였으며 열매체포는 물을 사용하였다. 본 연구에서는 열다이오드 시스템에 대하여 간단한 1차원 모델을 이용하여 시스템의 열성능을 평가하였으며 아울러 실측 결과와의 비교를 통하여 본 모델의 적용을 통한 시스템의 장기 예측에 대한 가능성을 확인하였다.