• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.11a
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• pp.486-489
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• 2011

건축물 내 외벽에 주로 사용되는 건축용 자재 중 샌드위치 패널은 양면으로 도장한 철판 사이에 심재로 단열재를 넣어 구성된 합성복합자재이다. 샌드위치 패널의 사용범위는 창고시설 및 공업용 건축 등의 용도로 많이 사용되고 있으며, 최근에는 시공에 따른 이점으로 주택 및 상업용등으로 널리 확대되어 사용되고 있다. 본 연구에서는 화재초기의 연기밀도는 인명 대피 시 시야확보에 있어 중요한 역할을 하기에 현재 국내에서 사용되는 건축용 외장재를 용도별로 선정하여 시간에 따른 연기밀도의 값을 구하고 용도에 따른 화재 연기의 확산 정도를 예측하는데 목적을 두었다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.04a
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• pp.424-428
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• 2010

본 연구에서는 통계적 분석방법을 이용하여 수도권지역(서울특별시, 인천광역시, 경기도)의 화재발생 유형에 대한 분석을 통하여 체계적이고 효율적인 소방정책을 수립하기 위한 기초 자료를 확보하는데 주안점을 두었다. SPSS와 Clementine 프로그램을 이용하여 소방방재청 국가화재정보시스템의 2007년과 2008년 화재발생 자료를 대상으로 기초통계분석(교차분석, 빈도분석)을 비롯하여 의사결정트리 분석 등을 수행하였다. 분석결과로서, 수도권지역의 화재건수는 2007년 이후부터 감소하거나 유지하는 경향을 보이고 있으며, 화재유형은 50% 이상이 건축/구조물에 의한 것으로 나타났다. 또한, 인명피해를 보면 서울시는 다른 수도권지역과 달리 2007년 대비 2008년 부상자와 사망자 수가 감소하였으며, 재산피해의 경우, 서울을 비롯한 대부분의 수도권지역에서 감소한 것을 확인할 수 있었다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.04a
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• pp.433-437
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• 2010

가을철 산불조심기간 중 영동지방(동해, 삼척) 침엽수림에 대하여 임분밀도별(소임분 800본/ha, 중임분 800-2000본/ha, 밀임분 2000본/ha 이상) 직경별 지표연료를 0.6cm 이하, 0.6~3.0cm, 3.0~6.0cm, 6.0cm 이상에 대하여 연료습도 변화를 실측한 결과 0.6cm 이하의 경우소임분은 3일차 되는 날 중, 밀입분은 4,5일차에 산불 초기 발화위험성이 나타났으며, 0.6~3.0cm의 경우 강우 익일 후 62-75%의 높은 연료습도를 보이고 있었으며, 소임분은 강우 후 5일차에 산불 초기발화 위험성이 시작되었다. 0.6~3.0cm의 경우 강우 익일에는 75-98%의 연료습도를 나타냈고, 소임분의 경우 6일차에 산불 초기발화 위험성이 시작되었다. 6.0cm 이상의 경우는 6일이 경과하여도 임분별 35-50%의 연료습도를 유지하고 있어서 산불 초기발화 위험성이 적은 것으로 조사 되었다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.04a
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• pp.429-432
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• 2010

본 연구에서는 산불발생 시 산림 내 연료들의 화재위험성을 분석하고자 산불에 취약한 소나무류(적송, 해송, 리기다소나무)의 솔방울을 대상으로 착화특성과 발연특성을 고찰하였다. 연료는 대형 산불이 빈번하게 발생하는 강원도 동해안 지역에서 채취하였다. 적송과 해송의 솔방울은 26%와 27%로서 함수율 차이가 크지 않았으며, 발화온도는 $380^{\circ}C$ 정도인 것으로 나타났다. 반면, 리기다소나무의 솔방울은 33%의 수분을 함유하였으며, 발화온도는 $352^{\circ}C$ 정도인 것으로 나타났다. 또한, 적송 솔방울의 최대연기밀도는 924Ds로서 해송의 599Ds와 리기다소나무의 605Ds 보다 상대적으로 높았으며, 690s~732s 시간영역에서 최대값을 보이는 것으로 나타났다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.04a
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• pp.55-58
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• 2007

This study investigates the spatting properties of high strength concrete, $60\sim80MPa$ class, designed with diverse aspect ratios and fiber content of nylon(NY). Test showed that increase of fiber content and aspect ratio in concrete decreased the fluidity of fresh concrete, especially for 1580 and 3000 aspect ratio of fiber. As for the compressive and tensile strength, adding NY fiber did not significantly affect the values In the range of high strength. After completing the fire test, the specimens containing both 750 and 1000 aspect ratios of fiber protected the spatting occurrence even in 0.05vol.% of fiber content. This specimens indicated the residual compressive strength ratio at 37%, showing the most favorable value among other specimens. Therefore, it is demonstrated that to protect the spalling in high strength concrete considering the effective fluidity, strength and economic efficiency altogether, adding 0.05vol.% of NY fiber with 750 aspect ratio Is beneficial.

• Journal of Periodontal and Implant Science
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• v.32 no.4
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• pp.847-855
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• 2002

It has been reported that Magnoliae cortex extract has antibacterial and antimicrobial activity against pathogenic microbes and Zea Mays L. extract is effective for improving gingival tissue health. The purpose of this study was to examine the anti-inflammatory and antimicrobial effects of Zea Mays L. and Magnoliac cortex extract mixtures through experimental peridontitis induced beagle dog model. Nine beagle dogs with experimentally induced periodontitis were selected. Baseline clinical indices which includes plaque index, gingival index, probing pocket depth, clinical attachment level, gingival fluid flow rate were recorded and microbial assays were done. Magnoliac cortex and Zea Mays L., mixed at 2:l ratio in 105mg capsular dosage, were taken by 3 capsule (Group I) or 6 capsule dosages (Group II) three times a day. After 4,8,12 weeks, clinical indices were recorded. All data of clinical indices were compared through one-way ANOVA with 95% confidence level. Clinical indices of group I and II showed significantly better results than those of control group. There were no significant differences between group I and II. In conclusion, it was confirmed that mixture of Magnoliae cortex and Zea May L. (mix ratio 2:1) possessed clinical improving effects to periodontitis.

• The Journal of the Korean dental association
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• v.21 no.10 s.173
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• pp.805-812
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• 1983

For the assessment of peripheral blood leukocyte chemotaxis dysfunction in rapidly progressive periodontitis, peripheral blood leukocyte of 13 patients were isolated, and tested by the method of blind well chamber technique which was recently developed by Park. Data analysis was performed from the speed of cell migration from the bottom of filter paper to the top for 18 minutes at the condition of chemo-attractant(Zymosan-activated serum). Eight of the 13 patients (62%) exhibited statistically significant inhibition of leukocyte chemotaxis, 4 patients revealed normal function and the other one patients showed elevated leukocyte chemotaxis. Four of the 8 patients in chemotaxis dysfunction showed significant inhibition of random migration and chemotaxis dysfunction both. Two of these 4 patients exhibited random migration impairment, elevation of C.D.I. and chemotaxis dysfunction. The results indicated that the progression of rapidly progressive periodontitis was influenced by the leukocyte chemotaxis dysfunction, and half of these dysfunction was associated with cell-defect of leukocyte.

• The Korea Journal of Herbology
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• v.25 no.1
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• pp.9-12
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• 2010

Objectives : To evaluate the extraction efficiency of water decoction with or without non-woven fabric underlying comparison of the HPLC (high-performance liquid chromatography) profiles of the hesperidin which is the standard of Citri Pericarpium. Methods : Pyungwisan, which is comprised of Atractylodis Rhizoma, Magnoliae Cortex, Citri Pericarpium, Glycyrrhizae Radix, Zingiberis Rhizoma, and Ziziphy Fructus, was extracted in boiling water with non-woven fabric or without non-woven fabric. Then hesperidin content was analyzed by HPLC. Results : The contents of hesperidin in the water extract of Pyungwisan which was decocted without non-woven fabric showed $219.57{\pm}2.51\;mg/g$ and $138.90{\pm}6.32\;mg/g$ in with non-woven fabric decoction. Conclusions : These results suggest that herbal decoction without non-woven fabric might increase extraction efficiency.

• Journal of Adhesion and Interface
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• v.10 no.4
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• pp.174-181
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• 2009

The viscosity for hi-solid pressure sensitive adhesive to improve water soluble low viscosity pressure sensitive adhesive polymerized using seeded polymerization. While seed binder polymerizing it produces an optimum polymerization condition, and acrylic acid and seed binder concentration changed were measurement of viscosity variation and adhesive power at the substrate (SUS420J) as flowing results. In adhesive polymerization, seed binder concentration 7 wt%/monomer was recovered 60% of solid content, 2,100 cps of low viscosity and clear adhesive film. When acrylic acid content was 4 wt%/monomer, it was turned excellent adhesive power and holding power.

• Journal of Power System Engineering
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• v.1 no.1
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• pp.80-90
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• 1997

The purpose of this study is to evaluate the validity examination of the J-R curve characteristics for the nuclear reactor pressure vessel steels and Al alloys by the load ratio analysis. The results of the load ratio analysis are compared with those of the J-R curve which are obtained by the ASTM unloading compliance method. The crack length calculated by the load ratio analysis is agree well with the measured final crack length. The slope of the exponential J-R curve estimated by the load ratio analysis is slightly smaller than that by the ASTM unloading compliance method. The J-R curve obtained by the ASTM unloading compliance method is over-predicted and should be offsetted due to the initial negative crack. On the other hand, the load ratio analysis method can evaluate the J-R curve by only load-displacement curve without particular crack measurement equipment.