몰리브덴이 첨가된 Stellite 6 합금의 마모와 부식특성

申種喆,金在洙,李德悅,梁在雄,尹珍國,盧大虎,李種權 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.10

Hardfacing layers of Stellite 6 with different molybdenum content are deposited on AISI 1045-carbon steel using Plasma Transferred Arc welding(PTA) machine. The microstructures, wear and corrosion resistances of the hardfacing layer are investigated in order to clarify the effect of molybdenum in Stellite 6 alloys. The microstructural characterizations of the hardfacing layers are performed using X-ray diffraction, back scattered electron images, and scanning electron microscopy. With an increase of Mo contents, M_6C type carbide are formed instead of Cr-rich type carbides, and so this microstructural change enhanced the mechanical properties such as wear and corrosion resistance of a Mo-modified Stellite 6 alloy.

음악 감상 교육에서 관현악 작품의 이해 연구 : 6차 교과서를 중심으로

이종웅 대구교육대학교 2001 論文集 Vol.36 No.-

인공 고관절 전치환술시 미세포말형 비구컵의 초기 안정성에 관한 생역학적 연구

박종웅,변영수 고려대학교 의과대학 1998 고려대 의대 잡지 Vol.35 No.2

The initial postoperative stability and intimate contact between the acetabular component with surrounding bone are essential for the bone ingrowth into porous-coated acetabular component. To achieve these goals in cementless acetabular component, press-fit of the acetabular component with or without adjuvant screw fixation is generally recommended. Many different models of acetabular components have been developed to achieve more bone ingrowth but they have been used without proven definite superiority over the others and different opinions exist in the advantage of adjuvant screw fixation. The purpose of this study is to investigate the gaps of bone-acetabular component interface, the initial mechanical stability and the effects of adjuvant screw fixation in the press-fitted two different shaped porous-coated acetabular components. Two different shaped cups: semi-hemispherical Harris-Galante Ⅱ cup and full hemispherical Trilogy cup, were press-fitted under 2mm under-reaming with or without adjuvant screw fixation in 40 bovine femur trabecular bone blocks. The implanted 40 specimens were divided into four groups with equal numbers of specimen. Harris-Galante Ⅱ cup was press-fitted in group 1. Harris-Galante Ⅱ cup was press-fitted with three adjuvant screws fixation in group 2, Trilogy cup was press-fitted in group 3 and Trilogy cup was press-fitted with three adjuvant screws fixation in group 4. In each radiography of all prepared specimen, the gaps of bone-implant interface were measured at polar portion, polar 1/3, middle 1/3 and peripheral 1/3. Implanted bone blocks were embedded in steel box and axial compression tests were per formed under 300kg load using servohydraulic tension-compression machine(Instron®-1331, Canton, Massachusetts, USA). The micromotions were determined in 5 specimens of each group using strain gauge transducer. Rotational stability tests were performed by determining the yield strengths in 5 specimens of each group. The results obtained were as follows; 1. Most of specimens had some visible gap at polar portion, polar 1/3 and middle 1/3 except peripheral 1/3, but there was significantly smaller gap at polar 1/3 region in the specimen implanted with Trilogy cup(p<0.05). The adjuvant screw fixation did not affect the amount of gap. 2. In the axial load test, the mean micromotion under 300kg axial load was 110.6±22.6㎛(range: 84.5㎛~136.0㎛) in group 1, 76.1±10㎛(range: 65.5㎛~91.5㎛) in group 2, 75.8±24.3㎛(range: 59.5㎛~118㎛) in group 3 and 95.5±26.4㎛(range: 74.0㎛~138.0㎛) in group 4 but there was no statistical difference in each group. 3. In the rotation test, the mean yield strength was 59.4F±22.3N.m(range: 37.2N.m~86.4N.m) in group 1, 62.6±15.7N.m(range: 42.3N.m~82.0N.m) in group 2, 41.8±14.0N.m(range: 23.7N.m~60.9N.m) in group 3 and 61.7±18.9N.m(range: 43.6N.m~90.2N.m) in group 4 but there was no statistical difference in each group. This study demonstrates that the initial mechanical stability is not influenced by the shape of semi-hemispherical Harris-Galante Ⅱ cup and full hemispherical Trilogy cup and also independent of adjuvant screw fixation. But smaller gap of Trilogy cup at the polar 1/3 region indicates the possibility that less amout of wear debris of polyethylene or metal will be deposited and therefore less osteolysis or cup loosening will occur, but this hypothesis should be confirmed by the long-term clinical follow-up.

韓國産 미꾸리에 關한 育種·繁殖學的 硏究 : Ⅴ. Ultrastructures Changes of Pituitary Gland and Testes in Male Loach Ⅴ. 미꾸리 수컷의 腦下垂體와 精巢의 微細構造

윤종만,노순창,김계웅,박홍양 건국대학교 동물자원연구센터 1993 動物資源硏究誌 Vol.18 No.-

본 연구는 1992년 3월부터 5월까지 자연채광 상태의 건국대학교 양어실습장에서 사육중인 한국산 미꾸리 수컷(Misgurnus anguillicaudatus)의 뇌하수체와 정소의 조직형태학적 변화를 이해하기 위해서 실시되었다. 미성숙 시기인 3월의 뇌하수체와 정소의 미세구조와 5월경의 성숙단계인 각 조직간의 발달상황을 비교 분석하기 위해서 광학 및 투과형 전자현미경을 이용하였다. 뇌하수체의 성선자극 호르몬이 분비되는 부위(GTH)의 발달은 정소의 주기적인 발달단계와 대체로 일치한다. 성성숙 지수(GSI)는 4월부터 5월에 이르는 시기에 증가하다가 정자세포와 정자의 수가 증가되는 5월에 가장 높게 나타났다. 하나의 小葉 속에 발달단계가 다른 nest가 들어있더라도 같은 정자형성 단계에 속한다. 미성숙 단계에서는 이형염색질이 분산되어 있다가 성숙 단계에서는 핵이 진하고 균질한 상태로서 존재한다. 핵막은 분화초기에 나타난다. 제1차 정모세포에는 15개 이상의 작은 미토콘드리아가 두부의 세포질 주변에 있다가 발달함에 따라 2개의 커다란 미토콘드리아로 변화되면서 한쪽으로 튀어나온 부위 주변에 위치하게 된다. 정자 중편부의 주위에는 미토콘드리아초와 외측 섬유소로 둘러싸여져 있다. This study was undertaken to understand the histomorphological changes of pituitary gland and testis of Korea loach(Misgurnus anguillicaudatus) under natural circumstances from March to May 1992. Sexual maturation was studied on 50 males Korean loach(Misgurnus anguillicaudatus). The results obtained in this study were as follows: The ultrastructures of the gonadotrophs largely parallel the cyclical changes in the testes. Gonadosomatic indices(GSI) increased from April to May, and showed the peak in May, coinciding with the increase of spermatids and spermatozoa in male. Each nest of cells belongs to one spermatogenetic stage, although nests at different stages can be found within the one lobule. At first heterochromatin is dispersed and then is condensed. In mature gamete, the nucleus is dense and homogeneous. The nuclear membrane appeared at the beginning of differentiation. In the primary spermatocytes, the small mitochondria are abundant over the outer cytoplasm. In the latter, the two large mitochondria are located over the cytoplasm. During cell differentiation, the cytoplasm decrease and the nucleus increases. Sperm mitochondria are assembled into an organized sheath surrounding the outer dense fibres and axoneme of the flagellar midpiece.

Digital Imaging Fiber-Optic Trans-Illumination을 이용한 초기 법랑질 우식병소의 조기 진단

염혜웅,김종수,유승훈 大韓小兒齒科學會 2004 大韓小兒齒科學會誌 Vol.31 No.4

치아 우식증의 발생과 관련된 분야에 대한 연구는 지난 20년간 활발히 진행되어 괄목할만한 발전을 이루었다. 그러나 치아 우식증의 원천적인 예방을 이루기 위해서는 보다 새로운 실험 장비와 기구를 이용한 다각적인 연구가 요구되며, 이러한 흐름에 부응하여 미국의 인디아나 치과대학을 중심으로 초기 법랑질 우식증에 관한 재조명이 집중적으로 이루어지고 있다. 또한 세계적으로 치과계의 지속적인 대민 교육과 홍보 및 불소화 사업 등의 우식 예방에 대한 노력과 구강 보건에 대한 대중의 인식 향상을 통해 치아 우식증이 감소하는 추세에 있으며, 이로 인해 치아 우식증이 기존의 교합면보다 인접면에서 더 많이 발견되는 추세로 변화되고 있다. 치아 우식증의 조기 진단을 목적으로 새로운 진단 장비들이 속속 개발되고 있으며 이미 성능의 우수성이 실험실 연구를 통해 입증된 바 있다. 본 연구의 목적은 초기 인접면 우식증의 진단에 있어 새로 개발된 DIFOTI^(TM) 시스템의 효능을 기존의 방법인 사진 및 교익방사선사진과 비교 평가하고, 임상 적용시의 문제점을 파악하여 차후 DIFOTI^(TM) 시스템 개발에 필요한 개선안을 제시함과 아울러 치아 우식증의 예방 및 불소를 이용한 초기 우식증 재광화 방법에 대한 기초 연구 자료를 마련하고자 하였다. 학동기 연령에 있는 유치 탈락 시기에 근접한 것으로 기대되는 23명의 아동을 대상으로 구강 검진 2회, 구치부 교익 방사선 필름 판독 2회 그리고 전치부 및 구치부 DIFOTI^(TM) 이미지 판독 2회를 실시하고 각 방법에 대한 신뢰도 평가를 시행한 결과 다음과 같은 결론을 얻었다. 1. 구강 검진시 검사자간 신뢰도는 교합면에서 평균 0.8470으로 가장 높았으며, 근심면 평균 0.6430 원심면 평균 0.5727, 설면 평균 0.2807 그리고 협면 평균 0.2339 순으로 나타났다. 구치부에 국한시킨 경우 교합면에서는 평균 0.8577이었으며, 원심면 평균 0.8211, 설면 평균 0.7728, 협면 평균 0.7152, 근심면 평균 0.6782 순으로 나타났다. 2. 구치부 교익 방사선 사진 판독 결과에 대한 검사자간 신뢰도는 교합면 평균 0.8346, 근심면 평균 0.8675, 원심면 평균 0.8482 순으로 나타났다. 3. DIFOTI^(TM) 이미지 판독 결과에 대한 검사자간 신뢰도는 교합면 평균 0.8437, 협면 평균 8379, 근심면 평균 0.8223, 설면 평균 0.7766, 원심면 평균 0.6781 순으로 나타났다. 4. 치아 우식증 진단율을 비교한 결과 교합면, 협면, 설면에서는 DIFOTI^(TM) 이미지 판독이 가장 우수한 것으로 나타났으며(p<0.05), 근심면과 원심면에서는 방사선 판독이 가장 우수한 것으로 나타났다(p<0.05). Over the past 20 years, great strides have been made in research regarding the mechanisms involved in the progression of carious lesions, but new equipment and research tools need to be developed to continue these advancements in caries research. Various methods have been applied to reduce the incidence of carious lesions, which have led to a significant decrease in the number of occlusal caries, but a concurrent increase in the proportion of proximal carious lesions. New diagnostic equipment has been developed to detect early stage carious lesions, and these have demonstrated excellent laboratory results and show promise in clinical applications. The research presented here examines the efficacy of the newly developed DIFOTI^(TM) system in detecting proximal carious lesions compared to traditional intraoral exam and bitewing radiography, possible problems or deficiencies of using the system in clinic, possible improvements that can be made to the system, and the efficacy of detecting early, reversible carious lesions that can be remineralized by preventative fluoride applications. The subject pool consisted of 23 grammer school age patients just prior to entering the mixed dentition phase. Each patient was given a thorough oral examination, radiographic examination consisting of bitewing radiographs of the posterior teeth, and DIFOTIR examination of the anterior and posterior teeth. Each examination was carried out two times by two examiners, and the data were statistically analyzed. The results are as follows: 1. The mean alpha value of reliability test of the visual oral examination was as follows: occlusal surface was 0.8470, mesial surface was 0.6430, distal surface was 0.5727, lingual surface was 0.2807 and distal surface was 0.2339. When the examination was limited to posterior teeth, the mean alpha value was as follows: occlusal surface was 0.8577, distal surface was 0.8211, lingual surface was 0.7728, buccal surface was 0.7152 and mesial surface was 0.6782. 2. The alpha value of reliability test of the radiographic analysis of carious lesions of the occlusal, mesial, and distal surfaces was 0.8500. 3. The alpha value of reliability test of the DIFOTI^(TM) diagnostic analysis of carious lesions of the occlusal, buccal, lingual, mesial, and distal surfaces was determined to be 0.7917. 4. The DIFOTI^(TM) diagnostic system was found to be the most accurate means of detecting occlusal, buccal, and lingual surface carious lesions (p<0.05), while mesial and distal proximal carious lesions were most accurately assessed using bitewing radiography (p<0.05).

變數選擇 技法에 관한 硏究

崔鍾碩,申敏雄 충남대학교 자연과학연구소 1979 學術硏究誌 Vol.6 No.1

Statistical procedure for selecting variable in regression is discussed in this article. we deals the problem of establishing a linear regression equation for a particular response Y in terms of "independent" variables X_(1), X_(2), . . ., X_(k). There is no unique statistical procedure for doing this. There may be the following procedures; (1) all possible regression (2) backward elimination (3) forward selection (4) stepwise regression (5) two variations on the four previous methods (6) stagewise regression We mainly discussed the stepwise regression and applied the principal component analysis for selecting some variables. Especially, in 1973 Alan B. Forsytle introduced a stopping rule for variable selection in multiple regression. The stopping rule dealed with the notion of householder rotation and permutation test. In this article we solved some problem by this rule.

혼합물실험계획에 의한 커피혼합비율 최적화에 대한 연구

이종성,문제웅 江原大學校 産業技術硏究所 2002 産業技術硏究 Vol.22 No.A

Many industrial products such as paints, ink and adhesives are composed of the ingredients of a mixture. In mixture experiments, the characteristics of quality(response) depends only on the proportions of the ingredients and does not depend on the total amount of the mixture. This article discusses the constrained mixture experimental design, the data analysis, and the optimum formulation of ingredients based on the two quality characteristics - taste and flavor. It is shown that efficient designs can be constructed from D-optimal criterion. Special cubic models were selected as the final mixture response surfaces for both reponses. The desirability function was used for the optimization of the two responses.

클로르헥시딘의 접착성 수복재의 결합에 미치는 영향에 관한 비교 연구

염혜웅,김종수,권순원 大韓小兒齒科學會 2002 大韓小兒齒科學會誌 Vol.29 No.1

치아 수복 후 나타날 수 있는 술 후 동통과 치수 병변의 주원인은 수복재 자체의 독성보다는 박테리아의 침투에 의한 것으로 알려져 있으며, 와동내 항균제 처리는 잔존 박테리아를 제거하여 제 증상을 완화하는데 효과적이지만, 상아질면이나 상아세관에 잔유물을 남겨 상아질 결합제와 치질간의 긴밀한 결합을 방해하여, 미세누출을 증가시키고, 결합강도를 약화시킬 수 있다고 알려져 있다. 2% 클로르헥시딘 도포가 접착성 수복물과 치질과의 결합강도 및 미세누출에 미치는 영향을 평가하기 위하여, 건전한 소의 전치 상아질을 노출시키고 와동을 형성한 후, 클로르헥시딘을 도포하고 복합레진, 컴포머 그리고 글라스아이오노머를 각 제조사의 지시에 따라 각각 충전하고, 100회 열순환 처리 후 전단 결합 강도와 미세누출 양상을 비교 평가하였다. 상아질 전단 결합 강도와 수복재 변연 미세누출 양상에서 실험군과 대조군간에 통계학적 유의차를 보이지 않았다. Bacterialmicroleakage around restorations is considered the principal cause of pulpal inflammation associated with restorations. The rationale for using cavity disinefectant is based on its antimicrobial properties but the cavity disinfectant may leave debris on dentin surfaces. The purpose of this study was to evaluate the effect of 2% chlorhexidine on shear bond strength and microleakage of adhesive restoration. 45 sound bovine teeth were used for the shear bond strength test and 30 for the micorleakage. For the experimental groups, 2% chlorhexidine was applied before the restorations, and was not for the control groups. The result from the this study can be summarized as follows; 1. No significant difference could be found in shear bond strength of each group. 2. No significant difference could be found in microleakage of each group.

균열저감형 생석회계 바닥마감 모르타르의 배합 및 입도조건 변화에 따른 팽창 및 건조수축특성

이종열,이웅종,박석균 대전대학교 산업기술연구소 1999 산업기술연구소 論文集 Vol.10 No.2

The cement based mortar is typically used as the surface finishing material for apartment floor. By the way, the crack is easily appeared with the lapse of time in this floor mortar because of the shrinkage effect of the cement. In our country, the most popular expansive additive is hauyne(CSA) or free lime(free-CaO) system. The types of shrinkage in the surface finishing mortar is known as plastic shrinkage, dry shrinkage and autogenous shrinkage. In this study, the expansive properties of the free lime system with various size distribution is analyzed. In particular, the experiment for the expansive properties is carried out by using the soundness molds and with various humidity and dry setting conditions. In addition, the difference of dry shrinkage properties between the cement with expansive additives and OPC is investigated under different conditions of water/cement ratio and sand/cement ratio.

EU의 Biomass를 이용한 에너지 생산

이종식,고문환,박우균,안종웅 한국국제농업개발학회 2003 韓國國際農業開發學會誌 Vol.15 No.3

EU 국가들의 1993년부터 1999년까지의 6년간 재생에너지 사용량 변화를 살펴보기 위하여 절대량 증가와 증가율을 조사하였다. 많은 나라들이 높은 사용량 증가 또는 증가율을 나타내었다. 초기에 재생에너지 사용이 적었던 나라들은 1999년에도 실질적인 생산량은 적지만 기간 중 높은 증가율을 보였다. 반면에 1993년에 이미 사용량이 높았던 나라들은 낮은 증가율을 보였으나 전체사용량은 높은 수준이었다. 재생 에너지 사용의 성공 여부는 보급 확대를 위해 많은 장해물들을 극복한 후에 성취될 수 있다. 보급 확대를 위한 요인들로는 정치적, 제도적, 재정적, 행정적인 지원과 기술개발, 홍보, 교육 및 훈련 등이 있다. Biomass를 이용한 에너지 생산 및 보급에 성공한 덴마크, 핀란드, 독일, 스페인 및 스웨덴의 송공 요인들을 소개하였다. In order to identify those Member State/technology combinations where there has been most success in achieving renewable energy penetration over the six-year period 1993-1999, the two selection criteria such as absolute increase and percentage of increase have been applied. Many Member States show either a large absolute increase in renewable energy output, or a large percentage of increase. Member States with only very low initial levels of renewable energy use may demonstrate rapid growth rates even though the actual quantity of output is still only small. Conversely, Member State with levels of renewable energy use that were already relatively high in 1993 show a less rapid percentage growth rate, but these Member States may still Have added significant quantities to the overall output. Successful penetration of renewable energy can only be achieved after overcoming many varied obstacles to an increase in their exploitation. Factors, which can influence the successful implementation of renewable energy projects, include political, legislative, financial administration, technological development, information, education and training. Examples of successful penetration of biomass power were shown for Denmark, Finland, Germany, Spain and Sweden.