WTO體制下의 貿易과 環境 論議

徐英哲,崔文燦 東亞大學校 經營問題硏究所 1995 經營論叢 Vol.16 No.-

품질보증수준확보를 위한 최적검사설비대수의 결정

송서일,조영찬 동아대학교 공과대학부설 생산기술연구소 1998 生産技術硏究所硏究論文集 Vol.3 No.1

As the rapid growth of industrial society, many enterprises are inclined to 100 ppm management, even more to ppm management from the traditional 3σ management method. Therefore, it needs to extend process capability index for guarantee of high quality assurance level to ppm unit. Thus, in this paper, using the probability of standard normal distribution from 3σ tp 6σ, which was developed by an author, the optimal numbers of inspection facility is determined for guarantee of process capability index and quality assurance level. Also, high quality assurance level is determined by considering the precision of inspection when one and two sided specification is given for the probability which is out of the specification limit.

公害規制가 貿易패턴에 미치는 影響

崔文燦,徐英哲 東亞大學校 經營問題硏究所 1994 經營論叢 Vol.15 No.-

대기 중 휘발성 유기화합물의 Advanced Technology에 대한 실험비교

최금찬,안병주,김석택,김찬훈,정창훈,서정민,유수영 동아대학교 환경문제연구소 2000 硏究報告 Vol.23 No.1

Nowaday, Advanced technology has been applied to organic destruction technologies that are alternatives to incineration. Plasma, photolysis, and Photocatalytic oxidation processes are an emerging advanced technologies for the abatement of volatile organic compounds(VOCs) in atmospheric pressure air streams, so we has been used these technologies for destruction of VOCs. TCE, Benzene, Toluene, and Xylene were selected as objective materials. We have been studied each process and found many types of reaction parameters which effect on treatment efficiency. So combination processes, which are plasma-photocatalytic oxidation process and photolysis-photocatalytic oxidation process, have been used to increase destruction efficiency. Analysis of above materials and byproducts was carried out by GC-FID.

L1210 세포증식에 대한 Glycyrrhizin의 억제작용 기전

殷載淳,徐龍勳,權鎭,柳東和,吳贊鎬,蘇俊魯,全焄,黃甲洙 우석대학교 의약품개발연구소 1996 藥學硏究誌 Vol.1 No.-

The purpose of this research was to investigate the mechanism of inhibitory action of Glycyrrhizin(GZ) on the proliferation of mouse leukemia cell-line, L1210 cells. The cytotoxic activity was tested using a colorimetric tertrazolium assay(MTT assay), the apoptosis was tested using flow cytometry. Nitric oxide(NO) production form mouse peritoneal macrophage was tested using a Griess method and the phagocytosis of human polymorphonuclear cells was tested using a lucigenin chemiluminescence. GZ ingibited the proliferation of L1210, BALB/c 3T3 cells and mouse thymocytes at 50 ug/ml/ GZ did not affect nitric oxide production from mouse peritoneal macrophages in vitro, but ingibited nitric oxide production from lipopolysaccharide and y-interferon treated macrophages. Macrophages of GZ-administered mice accelerated NO production. The proliferation of L1210 cells apoptosis of L1210 cells were induced by co-culture with macrophage of GZ-administered mice. The apoptosis of L1210 cells were induced by co-culture with macrophage of GZ-administered mice. GZ increased the phagocytosis of human polymorphonuclear cells. These results suggest that GZ inhibit the proliferation of L1210 cells not only as a direct cytotoxic agent o tumor cells, but also by the enhancement of NO production and phagocytic activity.

FWD를 이용한 콘크리트 덧씌우기 줄눈부에서의 하중전달효과 연구

양홍석,서영찬 漢陽大學校 工學技術硏究所 1998 工學技術論文集 Vol.7 No.1

콘크리트포장의 구조적 능력을 평가하는 가장 중요한 요소 중의 하나는 하중전달효과이다. 하중전달효과는 양쪽 슬래브의 처짐량비로 결정된다. 하중전달효과가 낮은 슬래브에서는 하중이 한쪽 슬래브에만 부하되어 콘크리트포장의 파괴를 촉진시키고 포장수명을 단축시킨다. 본 연구에서는 슬래브 온도, 다우월바 시공유무, 줄눈틈이 하중전달효과에 미치는 영향을 알아보기 위해 88 고속도로에서 FWD(Falling Weight Deflectometer)를 이용하여 다양한 온도조건에서 하중 전달효과 조사틀 실시하였다. 연구결과 다우월바를 시공한 구간에서는 온도변화에 관계없이 하중전달효과가 큰 차이를 보이지 않은 반면, 다우월바를 시공하지 않은 구간에서는 저온에서 하중전달효과 감소가 컸다. 또한 다우월바를 시공한 구간이라도 포장이 노후화되면 하중전달효과는 온도가 하락함에 따라 감소하는 것으로 나타났다. 본 조사대상 구간에서는 슬래브 단위온도 하락시 하중전달효과는 2.6% 감소하는 것으로 나타났다. One of the most important factors accounting for the structural capacity of concrete pavement is load transfer. Load transfer efficiency is determined by measuring deflection ratio across the slabs. In joints where load transfer efficiency is low, stress is concentrated in the loaded slab and accelerates the deterioration of the concrete, reducing the life of the pavement. In this study load transfer efficiencies were measured at various temperature conditions on 88 Express Highway using FWD(Falling Weight Deflectometer) in order to find the effects of slab temperature, construction of dowel bars, crack width at the joint on the load transfer efficiency. For the sections with dowel bars, there were little differences in load transfer efficiency regardless of temperature changes. For the sections without dowel bars, however, there were great losses of load transfer efficiency at low temperatures. For the old pavement, even in the sections with dowel bars, the load transfer efficiency reduced as the temperature dropped. For the sections in this study, 2.6% reduction of the load transfer efficiency was observed for each 1 ℃ drop in the slab temperature.

폐콘크리트 재활용을 위한 재생골재 혼합에 따른 강도특성분석

조규태,서영찬 漢陽大學校 工學技術硏究所 2002 工學技術論文集 Vol.11 No.-

본 연구에서는 최근들어 다량으로 증가되고 있는 폐콘크리트의 재활용 여부를 판단하기 위해서 천연골재에 대한 재생골재를 중량비로 0%, 30%, 50%, 70%, 100%비율로 혼합한 재생콘크리트의 강도특성을 비교하였다. 재생골재 각 조합의 물성시험을 통해 골재의 물성치를 확인한 다음 콘크리트의 배합설계를 하였다. 배합설계는 상대비교를 위해 단위골재량 값만을 변화시키고 다른조건들은 동일하게 하였다.또한 플라이애쉬, 고성능 감수제를 첨가한 혼합물의 내구성과 작업성 문제에 대해서 고찰하였다. 재생골재의 물리적 특성 시험결과 재생굵은골재와 재생잔골재 모든 조합에서 비중은 KS의 1종 재생골재,흡수율은 2종 재생골재 기준을 만족하였으며, 특히 재생골재 대체율 50%까지는 자연골재와 동일한 물성값이 나타났다. 기존의 폐콘크리트는 대지조성재, 기초 매립재등으로 이용하고 있으나 본 시험을 통해 재생골재를 사용한 콘크리트의 적용이 도로포장재료로서 가능하다는 결론을 얻었다. The strength characteristics of recycled concrete is compared to study the feasibility of the recycled aggregate made of the scrapped dump cement concrete for five compound aggregate types consisted of natural aggregate and recycled aggregate as the ratio of weight(0%, 30%, 50%, 70%, 100%). First of all, the physical characteristics of recycled aggregate compounds were tested and the mix design was conducted. Every factors, except the unit aggregate amount, were fixed for the relative comparison. Fly-ash and the super water reducing agent were added to the recycled concrete to ensure the workability. The results of test, the recycled coarse aggregate, recycled fine aggregate and all compounds of recycled aggregate were satisfied with the specification(KS) of the type Ⅰ recycled aggregate in terms of the specific gravity, and the type Ⅱ specification in terms of the absorption. Especially, up to the maximum 50% replacement of recycled aggregate, the properties were equal to natural aggregate. Although most of recycled concrete were used for the land fill, this study showed the feasibility of recycled aggregate as the concrete mix.

도로포장시공시 세립분 함유량변화에 따른 입상재료의 적용성 연구

조규태,서영찬 漢陽大學校 工學技術硏究所 2002 工學技術論文集 Vol.11 No.-

도로포장재료중 보조기충과 동상방지층 재료로 강자갈등의 천연재료 사용이 일반적이었으나 90년대이후 하천골재의 고갈로 인하여 석산에서 채취한 파쇄골재를 사용하고있다. 골재 생산과정에서 세립분의 혼입은 보조기층 및 동상방지층 재료의 역학적 특성과 동상에 많은 영향을 미치게 된다. 본 연구에서는 보조기층 및 동상방지층 재료의 중량비로 세립분 함유중량을 10%, 20%로 변화시키고 소성지수갑(pl)을 6, 10, 15로 변화시켜 재료의 물성시험, 다짐시험, 실내CBR시험, 투수시험, 동결융해시험을 하였다. 실내시험을 통하여 얻은 결론은 지지력, 투수성, 동결융해저항성을 만족한 보조기층은 소성지수 10, 세립분 함유량 10%까지 적용이 가능하며, 동상방지층은 소성지수 15, 세립분 함유량 10%까지 사용이 가능한 것으로 판단되었다. Generally natural materials such as river gravel are used for the subbase and non-frostsusceptible base of the pavement. However, site substitute of the crushed stone for natural materials, due to the shortage of aggregate resources has been prevail since 1990_s. The clayey soil mingles with crushed stone during the process of production, and this affects on the mechanical characteristics and the freezing of pavements. Lab tests conducted includes materials test, compaction test, CBR test, permeabillity test, and freezing & thawing test. The ratio of clay content of the specimens were 10% and 20%. the plastic index values were 6, 10, and 15. Considering the bearing capacity, permeability, and the resistance of freezing & thawing, the plastic index of 10 and the clay content of 10% for the subbase and the plastic index of 15, the day content of 10% for non-frost layer showed satisfactory results, respectively.

콘크리트 덧씌우기 전후 비교조사에 따른 덧씌우기공법의 지지력 및 하중전달 특성 연구

권순민,서영찬 漢陽大學校 工學技術硏究所 1997 工學技術論文集 Vol.6 No.1

A 290m 2-lane experimental concrete overlay was constructed in 88 Express Highway to investigate it's feasibility in Korea. The test section consists of both bonded and unbonded type overlays. Pavement condition of the existing slab was surveyed before overlay, and construction feasibility of concrete overlay was checked during construction. After overlay, delamination, crack, deflection(using FWD), and load transfer at various temperature conditions have been measured periodically. Findings from the study can be summarized as follows. (1) The overlays performed successfully during at least 1 year after construction, (2) Overlay reduced deflection by 47% in bonded overlay section and by 57% in unbonded overlay section, (3) Unbonded overlay showed better load transfer than bonded overlay, (4) Joints transfer dowel bar showed better load transfer than those without dowel bar, and (5) Load transfer efficiency varied with temperature conditions.

완충 용액의 유산 농도와 pH가 법랑질의 재광화에 미치는 영향

권중원,서덕규,송윤정,이윤,이찬영 大韓齒科保存學會 2008 Restorative Dentistry & Endodontics Vol.33 No.6

There are considerable in vitro and in vivo evidences for remineralization and demineralization occurring Simul-taneously in incipient enamel caries. In order to "heal" the incipient dental caries, many experiments have been carried out to determine the optimal conditions for remineralization. It was shown that remineralization is affected by different pH, lactic acid concentrations, chemical composition of the enamel, fluoride concentrations, etc. Eighty specimens from sound permanent teeth without demineralization or cracks, 0.15 mm in thickness, were immersed in lactic acid buffered demineralization solutions for 3 days. Dental caries with a surface zone and subsurface lesion were artificially produced. Groups of 10 specimens were immersed for 10 or 12 days in lactic acid buffered remineralization solutions consisting of pH 4.3 or pH 6.0, and 100, 50, 25, or 10 mM lactic acid. After demineralization and remineralization, images were taken by polarizing microscopy (×100) and micro-computed tomography. The results were obtained by observing images of the specimens and the density of the caries lesions was determined. 1.As the lactic acid concentration of the remineralization solutions with pH 4.3 was higher, the surface zone of the carious enamel increased and an isotropic zone of the subsurface lesion was found. However, the total decalcification depth increased at the same time 2.In the remineralization solutions with pH 6.0, only the surface zone increased slightly but there was no significant change in the total decalcification depth and subsurface zone. In the lactic acid buffer solutions with the lower pH and higher lactic acid concentration, there were dynamic changes at the deep area of the dental carious lesion. 본 연구의 목적은 유산 완충 용액의 pH및 유산 농도 변화가 법랑질에서 인공 우식 병소의 재광화 양상에 미치는 영향을 평가하기 위함이다. 유산 완충 용액을 이용하여 법랑질을 탈회시키고, 유산의 농도가 100, 50, 25, 10 mM이고 pH가 4.3인 네 가지 재광화 용액 (Group 1, 2, 3, 4)에 10일, pH 6.0인 네 가지 재광화 용액 (Group 5, 6, 7, 8)에 12일간 처리한 후 무기질의 양적 변화를 편광 현미경에서 얻은 상에서의 탈회 깊이의 변화, 우식 표면층 깊이의 변화로 측정하였다. 또한 micro-computed tomography (micro-CT)를 이용하여 탈회 후와 재광화 후를 촬영하여 얻은 상으로부터 lesion부위의 density를 비교하였다. 1. pH 4.3에서 유산 농도가 증가할수록 우식 표면층의 증가와 표층하 탈회부 중 심층부의 isotropic zone등의 재광화 현상을 보이나, 전체 탈회 깊이 역시 증가하였다. 2. pH 6.0에서 우식 표면층에 국한된 재광화 현상을 보이고, 전체 탈회 깊이는 변화가 없었다. 이상의 실험 결과로 미루어 포화도가 일정한 유산 완충 용액으로 재광화 유도시 pH가 낮고 유산의 농도가 높을수록 표면으로부터 심층부 동역학적 변화에 더 영향을 주었으며, micro-CT를 이용한 우식 병소부위의 density 확인을 통해 무기질의 침착과 방출 현상을 객관적으로 평가할 수 있었다.