鋼纖維補强 시멘트 複合體의 力學的 特性

차희석 경남대학교 신소재연구소 1997 論文集 Vol.9 No.-

본 연구에서는 강섬유보강 시멘트 복합체의 고성능화를 위한 기초적 연구의 일환으로 두 종류의 실험적 프로그램이 수행되었다. 시리즈 1에서는 실리카 흄과 폴리머의 첨가량을 변화시켜 강섬유가 혼입된 시멘트 복합체에 대해 역학적 특성을 고찰하므로서 모체성능을 개선하기 위한 시험이며, 시리즈 2에서는 앞의 결과에서 결정된 범위내에서 모체내에 길이가 다른 두 종류의 섬유를 첨가하여 역학적 거동을 비교, 고찰하였다. 얻어진 결과로는 모체내에서 실리카 흄의 첨가는 강섬유의 부착특성을 개선시켰으며, 폴리머는 모체의 연성을 증진시켰다. 또한 직경이 동일한 경우에 긴 섬유의 혼입은 복합체의 인성을 증가시키기는 하나 워커빌리티가 감소하므로 짧은 섬유를 다량 첨가하는 것이 역학적으로 특성을 더욱 개선시킬 수 있는 방법임을 알았다. This study has two purposes. One is to investigate the effects of concrete admixture such as silica fume and polymer on mechanical properties of concrete. The other is to analyze the effect of length of steel fiber on fracture toughness. This study found that addition of silica fume improved the bonding properties, and addition of polymer increased the ductility of matrix. It also found that composites with long fibers had higher fracture toughness than those with short fibers. However the workability of composites with longer fibers was inadequate.

한국인 국소유년형 치주염환자의 치료 전후 임상, 미생물 및 면역학적 연구

손성희,정종평 대한구강생물학회 1989 International Journal of Oral Biology Vol.13 No.1

To investigate on the factors associated with disease progression of 9 early juvenile periodontitis, clinical, microbiological and immunological studies were performed at the mesial pocket of a first molar on the day of first visit, 9 months after observation without treatment and 6 months after treatment. Clinical parameters are included in sulcus bleeding index (S.B.I.), plaque index, alveolar bone resorption, and attachment loss. Microbiological studies are included in the proportion of bacterial morphotype and anaerobic culture of predominant cultivable microflora. Immunological studies are also performed with the assay of PMN chemotaxis dysfunction, and IgG, and IgM antibody levels to A. actinomycetemcomitans. Through subdivision of 9 subjects with non-progressing and progressing based on the changes in value of alveolar bone resorption and attachment loss, 1. Progressing group showes higher values of S.B.I than non-progressing group. 2. In bacterial morphotype analysis, the distribution of spirochetes are higher in the progressing group than non-progressing group based on alveolar bone resorption. 3. The proportion of anaerobic microflora shows higher in the progressing group than non-progressing group based on alveolar bone resorption. 4. A. actinomycetemcomitans revealed significantly higher frequency in progressing group than non-progressing group, and no detection after treatment. 5. There is no significant differences of PMN chemotaxis dysfunction between progressing and non-progressing group, and suggested to be no correlation with disease progression. 6. IgG antibody levels show significantly higher in non-progressing group than progressing group. However, IgM antibody levels show significantly higher in progressing group than non-progressing group based on alveolar bone resorption, and significantly reduced antibody levels after surgery. These results suggested that infection of A. actinomycetemcomitans and their negligible antibody levels might be relevant factors for progression of early juvenile periodontitis.

치주염의 원인균 및 정상상주균간의 길항기전 규명 및 치주치료에의 응용

손성희,정종평,김각균,김강주 대한구강생물학회 1991 International Journal of Oral Biology Vol.15 No.1

It has been reported that microbial distribution and colonization in oral cavity have a relation to antagonism, synergism or symbiosis among microorganisms and bacterial antagonism have a relation to bacteriocin, hydrogen peroxide and bacterial metabolic end-products. The purpose of this study is to investigate on the in vivo and in vitro ecological interrelation and to detect the growth inhibition subatance and to clarify the antagonistic mechanism of the periodontopathic bacteria. In vivo ecological interrelation was studied by bacterial isolation & identification and in vitro ecological was studied by stab culture method. Bacteriocin-like substance was examined, purified, electrophoresed, and stained with silver stain. After the producer microorganism was cultured in various conditions, the pH & bacterial end-products of it was examined and the susceptibility of indicator bacteria by pH was measured. The presence of plasmid DNA was investigated by hot-boiling method. In in vivo ecologic interrelationship, Actinobacillus actinomycetemcomitans(Aa) was not isolated, black-pig-mented Bacteroides was less in the presence of Actinomyces species than in the absence of it in refractory periodontitis. In in vitro ecologic interlationship, S. mutans showed strong growth inhibitory activity against Porphyromonas gingivalis and Aa strains and more strong growth inhibitory activity against Aa Korean isolates than S. sanguis. After bacteriocin-like substance was examined, purified, electrophoresed, and stained with silver stain, a band was appeared whose molecular weight was 36 kd, pH and the production rate of lactic acid was varied according to the presence and absence of oxygen and glucose. These results suggested that there exists in vivo and in vitro growth inhibition among oral microorganisms and growth inhibition was affected by bacteriocin-like substance, pH and bacterial end-products of producer strains and sensitivity of indicator strains. Animal study is needed by using strains of growth inhibition and growth inhibitory substance.

HPSFRC 引張部材 擧動豫測 모델 開發

車熙石,姜枰求 경남대학교 신소재연구소 1997 論文集 Vol.9 No.-

본 연구에서는 기존에 제안된 모델을 이론적으로 고찰하므로서 그 특성을 파악하고, 고성능 강섬유보강 콘크리트의 인장거동을 예측하기 위하여 확률론적 개념을 도입하여 인장모델을 제안하였다. 시험에서 얻어진 결과치로 보다 정확하고 합리적인 인장모델을 적용하였으며, 이론적으로 유도되는 모델의 계수산정을 위해 인장시험 데이터를 회귀분석하였다. 제안된 모델은 실험결과치를 만족스럽게 표현하였으며, 강섬유보강 콘크리트의 역학적 특성을 개선할 수 있도록 섬유의 기하학적 설계, 경화특성을 규정하여 구조적인 설계에 기초적 자료로 사용될 것으로 기대된다. In this study, an analytical model to predict the tensile behavior of High Performance Steel Fiber Reinforced Concrete(HPSFRC) was developed. From literature review and experimental results pull-out mechanism and mechanical behavior under tension were studied. This model predicts the elastic and post-cracking behavior of HPSFRC by considering the tensile stress-strain responses, and simulation results by this model were in line with experimental results. It is expected that this model will be a useful tool in designing new fiber geometries.

DAF공정의 궤적분석에서 유선과 운동함수의 적용이 기포와 플록의 충돌효율에 미치는 영향

김성진,곽동희,임영환 한국물환경학회 2004 한국물환경학회지 Vol.20 No.6

Many researchers have been carrying on study to figure out the exact collision efficiency between bubble and floc. Collision efficiency can has generally been quantified by using trajectory analysis which uses the hydrodynamic, the electrostatic and van der waals forces. Two types of method are considered to induce the hydrodynamic force in the trajectory analysis. One is to use stream function and the other is to use mobility function. There was some difference between stream and mobility function depending upon modelling factors and conditions in trajectory analysis.

원수중의 천연유기물이 부상분리공정에 미치는 영향

곽동희,정팔진,이성우 全北大學校 附設 都市및環境硏究所 1997 都市 및 環境硏究 Vol.12 No.1

Many water bodies used for water supply may contain solid particles with a lower density. These solids are hardly removed in the sedimentation unit due to the own tendency of floating. In order to treat this type of water, the flotation process in known to be an effective method. A series of laboratory experiments has been performed to investigate the effect of natural organic matter(NOM) in raw water on flotation process. Foam formation potential(FFP) could be increase by NOM in raw water, alum is stimulate the trend of FFP to increase. Results of DAF treatment studies show that flotation efficiency can be increase by AOM, such as ethyl ester, sodium propionate, sodium dodecylbenzenesulfonate. Meanwhile, flotation efficiency can be decrease by AOM, such as glycerol, starch, pentane, peptone, isoamyl alcohol, humic acid etc. Also, the flotation efficiency by AOM corresponds well the tendency of FFP.

Pilocarpine 및 Atropine이 토끼의 악하선 혈류랑에 미치는 영향에 관한 연구

이종율,손성희,이종흔 대한치과페리오학회 1975 大韓齒周學會誌 Vol.5 No.1

인슐린 비의존형 당뇨병 환자에서 혈장 Endothelin-1농도의 변화

신양수,조희충,김원식,국기용,김용화,정종훈,문철웅,배학연,양성훈 朝鮮大學校 附設 醫學硏究所 1992 The Medical Journal of Chosun University Vol.17 No.2

Endothelin(ET) is a 21-residue peptide originally isolated from the cultured porcine endothelial cells. There are at least three genes for endothelin:endothelin-1(ET-1), endothelin-2(ET-2), and endothelin-3(ET-3). Endothelins are present in various human biological fluids including plasma, urine, breast milk, and saliva and have been found elevated plasma ET concentrations in patients with diabetes mellitus, Patients undergoing maintenance hemodialysis due to chronic renal failure, patients with acute myocardial infarction, and patients with subarachnoid hemorrhage. Endothelial cell damage is suspected to occur in diabetic patients and may be one important cause of angiopathy, a major complication in diabetes mellitus. The elevation of ET in diabetic patients may be a marker of, and further exacerbate, their vascular disease. We measured the levels of ET-1 in plasma of 50 patients with non-insulin dependent diabetes mellitus(NIDDM) and 25 normal subjects by radioimmunoassay. The plasma ET-1 concentration (mean±S.D.) in NIDDM was 6.461 A2.510 f㏖/ ㎖, and was significantly higher than in normal subjects (4.567±1.155f㏖/㎖) (P<0.05). The plasma ET-1 concentration (mean±S.D.) in diabetic retinopathy group( 7.15±2.454 f㏖/ml) was significantly elevated than those in otherwise uncomplicated groups (5.348±2.390 f㏖/㎖)(P<0.01). The correlation between any clinical parameters and plasma ET-1 levels in NIDDM was not significant, In conclusion, this study suggest that the elevated levels of ET-1 in diabetic patients may be play a important role in the pathogenesis of diabetic complications.

정상 및 염증치은의 혈류량변동에 관한 연구

장계순,손성희,이종흔 대한치과페리오학회 1975 大韓齒周學會誌 Vol.5 No.1

생약 추출물이 세포성장 및 cytokine 생산에 미치는 영향

류인철,손성희,정종평,배기환 충남대학교 약학대학 의약품개발연구소 1993 藥學論文集 Vol.9 No.-

The native connective tissue attachment of the periodontium is known to be a complex consisting of gingival fibroblasts, periodontal ligament cells, gingival epithelial cells, cementum, alveolar bone and extensive extracellular matrix (collagen, glycoprotein and proteoglycans). The purpose of this study was to evaluate the effects of natural extracts on DNA, collagen and protein synthesis and inhibition of cytokine production in the gingival and periodontal ligament fibroblasts and gingival epithelial cells. Healthy gingibal tissue was obtained from orthodontic treatment patients, and gingival epithelial cells, gingival fibroblasts and periodontal ligament cells were isolated and cultured from the samples. After treated with Ginseng protein, Pluronic F-68, Scutellariae Radix, centella asiatica, PDGF, IGF, DNA synthesis, total protein and collagen synthesis, and cytokine production of gingival epithelial cell, gingival fibroblast and periodontal ligament cells were measured. MTT method for DNA synthesis, Peterkofsky and Dingerman method for total protein and collagen synthesis, and IL-1 ELISA kit for cytokine production were used. The proliferation of epithelial cells was enhanced in Centella asiatica, Ginseng protein, Pluronic F-68 and Scutellariae Radix. The activities of PDL cells were increased in PDGF, IGF, and Pluronic F-68. Higher collagen synthesis was observed in Scutellariae Radix and total protein synthesis was increased in Scutellariae Radix and PDGF. The inhibitory effects on IL-1, IL-6, TNF-α were observed in all exrracts.