• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2004년도 학술대회지
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• pp.350-354
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• 2004

In this study, the wear characteristics of five different dental composite resins cured by conventional halogen light and LED light sources were investigated. Five different dental composite resins of Surefil, Z100, Dyract AP, Fuji II LC and Compoglass were worn against a zirconia ceramic ball using a pin-on-disk type wear tester with 15 N contact force in a reciprocal sliding motion of sliding distance of 10 mm/cycle at 1Hz under the room temperature dry condition. The wear variations of dental composite resins were linearly increased as the number of cycles increased. It was observed that the wear resistances of these specimens were in the order of Dyract AP > Surefil > Compoglass > Z100 > Fuji II LC. On the morphological observations by SEM, the large crack formation on the sliding track of Fuji ?LC specimen was the greatest among all resin composites. Dyract AP showed less wear with few surface damage. There is no significant difference in wear performance between conventional halogen light curing and light emitting diodes curing sources. It indicates that a light emitting diodes (LED) source can replace a halogen light source as curing unit for composite resin restorations.

• 열처리공학회지
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• 제19권1호
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• pp.30-36
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• 2006

Fretting fatigue behavior of SCM420 steel commonly used in the automotive industry for structural applications was investigated in this study. In addition, the effect of bridge pad on the fretting fatigue test was evaluated from different pad materials and following conclusions were drawn. Simple fatigue limit of SCM 420 steel was determined to be 350 MPa while this value was 225 MPa and 285.5 MPa with SCM420H and with SM45C pad, respectively. Reduction in fatigue limit was, thus found to be 35.7% and 17.9% with SCM 420H pad and SM45C pad, respectively. Results of fracture surface observation revealed that typical striation pattern of fatigue failure existed as well as dimpled and cleavage frature appearance was found in final fractured region. From the EDS compositional analysis, test sample and pad part all had high signals for oxygen and iron, suggesting that worn particles might be iron oxide, although exact chemical composition has to be confirmed. Considerable reduction in fatigue life was apparent in SCM 420 steel under fretting fatigue against simple fatigue. Such reduced fatigue life by fretting damage should be considered as an important factor not only in the viewpoint of repairing but also inevitably in the design stage of structural components.

• 한국콘텐츠학회논문지
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• 제17권1호
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• pp.740-749
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• 2017

금석문(金石文)이란 금속이나 석재에다 새긴 글씨 또는 그림을 말한다. 금석문(金石文) 판독에 널리 사용되고 있는 탁본은 간편하다는 장점을 가지고 있다. 하지만 해상도나 노이즈 관점에서 볼 때 탁본은 금석문 판독에 최적의 방법이라고 할 수는 없다. 본 연구에서는 각자된 글자의 입체적 특징을 반영하여 판독 가능성을 높여주는 새로운 조사기법을 제시하였다. 금석문에 각자된 글자의 정밀한 입체 데이터를 얻기 위해 3차원 스캐닝 기술을 적용하고 획득된 3차원 깊이 데이터에 따라 음영을 표현하는 Ambient Occlusion 시각화 기법을 적용하였다. 이 과정에서 훼손 및 마모가 포함된 바탕영역정보와 글자영역정보를 분리하여 판독 가능성을 향상시켰다. 개발된 방법은 국보318호인 포항중성리신라비의 판독에 적용하여 그동안 판독에 논란이 있어왔던 특정 문자의 판독 뿐 아니라 추독 범위를 좁히는데 기여하였다.

• Nuclear Engineering and Technology
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• 제6권4호
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• pp.239-247
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• 1974

방사선 안전관리의 효과적인 연구를 위해 유사인체 모형을 설계, 제작하였다. 이 모형의 치수는 한국인의 체격과 근사하게 맞추었으며 두께 2.5cm인 포리에칠렌판 35매로 구성되었다. 유사인체모형의 표면에 착용한 열형광 설량계(Disc type TLD)로써 외부 ${\gamma}$-방사선에 의한 신체특정부위의 피폭선량을 측정하였으며, 아울러 깊이에 따른 흡수선량에 대해서 열형광 선량계(micro rod type TLD)로써 측정하여 결정장기 부위의 각단면에 대한 등가선량선을 얻었다. 선량측정은 방사선 작업자의 작업환경조건에 유사하도록 유사인체 모형에 대해 배치하고 여러 입사방항에 대해서 실시하였다. 그 결과 Cs-137, ${\gamma}$-방사선에 대하여 두께 20cm인 유사인체 모형에서의 감쇄는 0.439였으며 이는 보고된 자료들과 잘 일치하였다.

• 복식문화연구
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• 제6권1호
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• pp.136-148
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• 1998

This is a study on the change of the Medievalmen's underclothes. Underclothing includes all such articles, worn by either sex, as were completely or mainly concealed from the spectator by the external costume. Throughout the Middle Ages, the underclothing of both sexes possessed characteristic inherited from earlier times. Its function was purely utilitarian. It was not used to express class distinction and only very indirectly to enhance sex attraction. The idea of underclothes was associated with the idea of the body's sinfulness. Underclothes could also symbolize the discipline of humility. To appear clad only in underclothes was a voluntary form of selfabasement often practised by pilgrims. The notion that underclothes might express the spirit of the changing times, in sympathy with the outer clothing, did not enter the medieval mind. The length of the shirt was less than that of the modern garment, especially after the middle of the fourteenth century. The sleeves were somewhat full, without cuffs, and cut straight. During the second half of the twelfth century, when braies become definitely an undergarment. In the fourteenth century braies became shorter and shorter and the shirt could no longer be tucked in but hung outside over the thighs. After 1340 the costume on the surface somewhat resembling modern 'tights', began to reveal display the shape of the male leg as a form of sex attraction. By the close of the Middle Ages, braies had become less like loincloths, and more like modern bathing trunks. The peasant and laborer did not attempt to keep pace with the changes of fashion but, continued, as a rule, to wear the long braies of their forefathers. The higher ranks how this garment reflected the changes of the mode of outer costumes.

• Journal of Periodontal and Implant Science
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• 제34권1호
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• pp.61-70
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• 2004

연구 목적: 3개월 간의 잇솔질에 따른 칫솔의 마모의 정도와 양상을 관찰하고, 이를 이용한 잇솔질 시의 치태 제거능력의 변화를 평가하여 일반적으로 권장되고 있는 3개월 주기의 칫솔 교체 주기의 근거를 실제 임상적으로 확인해보고자 하였다. 연구방법: 치주적으로 건강한 치과 대학생 52명을 대상으로 설문지를 통해 잇솔질 습관을 조사하고, 치석제거술을 시행하고 실험기간 동안 동일한 칫솔과 치약을 사용하게 하였다. 1주일 후와 2달과 3달째에 구강 내를 erythrosine으로 염색한 후 6개의 Ramfjord 치아의 plaque score를 측정하고, 3달 동안 사용한 칫솔을 수거하여 brushing surface area의 면적으로 마모도를 평가하였다. 결과: 6명이 탈락하였고 전체 부위의 plaque score는 1주 때와 비교하여 2,3 개월의 값이 통계학적으로 유의한 차이가 없었으나, 치간 부위의 plaque score는 3개월의 plaque score와 상관관계는 약하였다. 교체 주기, 잇솔질 횟수, 시간 등의 잇솔질 습관과 마모도의 연관성도 없었지만, 잇솔질 시간과 3개월째의 plaque score의 상관관계는 유의성 있는 결과를 보였다. 결론: 3개월 동안 사용한 칫솔의 치간 부위 치태제거 능력은 감소하였으며, 이의 임상적 영향에 대한 장기간의 연구가 필요하겠다.

• 복식
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• 제65권8호
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• pp.110-124
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• 2015

This study examined a phenomenon of exaggerated hairstyle in the history of Western custom through publications related with Western costume and research papers. By adopting the criteria of Delong, M. R. to analyze visual forms shown by interaction between human body and costume worn over the body, it analyzed the formative characteristics by the interaction between hairstyle and costume. In addition, it inferred the aesthetic characteristics through content analysis of examined phenomenon focusing on socio-cultural background and costume socio-psychological precedent studies. Formative characteristics of exaggerated hairstyle applied by analysis criteria of Delong, M. R. were in pursuit of the emphasis style. This was clearly and intensively recognized by forming spaces for mostly closure style, part style, three dimensional style, determinate style, and space separation style. Regarding the interaction between hair and ornamentations, 'precedence of ornamentation' was pursued as ornamentations were recognized earlier than the hair itself. It means associative meanings of the surface effect were accompanied by emotions of 'intensiveness' and the pursuit of the attractive style. As for the interaction between hairstyle and costume, there were many cases of pursuing 'continuity' mutually and visually by connecting the hairstyle and the costume. Aesthetic characteristics of exaggerated hairstyle were inferred as 1) the expression of the sprite of the age(i.e. art, culture, politics, society, ideology, religion), 2) symbols of wealth, class, authority, and excellence, 3) pursuit of addicted desire to ornament, and 4) harmony through continuity with costume. This study verified that hairstyle was connected as a part of costume, or formed as a way to express deeper human psychology beyond just a part of a costume. It was also confirmed that hairstyle was an expressive method to express the spirit of the age, such as art, culture, society, religion, ideology.

• Journal of Advanced Marine Engineering and Technology
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• 제31권6호
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• pp.753-760
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• 2007

For protection of the cylinder wall of the ball mill for grinding raw ore. the inner side of the cylinder is covered with rubber liner. The rubber is easily worn down because the rubber relatively soft compared with raw ore. So the rubber liner in the ball mill cylinder must be replaced almost every year and the cost for replacing rubber liner formidable. In this paper, for reducing or excluding the cost of replacing rubber liner the basalt liner is designed. The basalt materials are generally harder than raw ore and the basalt liner in the ball mill does not wear down and so it can be used almost permanently. The concave surfaces are made on the liner of the ball mill and the liner in the cylinder wall plays also the role of raising the steel balls mixed in the raw ore. The section profiles of the concave surface have an important effect on the performance of the ball mill. The deep concave grooves raise the steel balls to high levels and give the large potential energy to the steel balls impacting to the raw ore. But if the concave grooves are too deep. the steel balls raised too high by the concave grooves fly along the parabolic path and reach to the other side of cylinder wall and so the steel balls do not play the roles of grinding the raw ore. The forces acting to a steel ball in a concave groove of the cylinder liner are also analyzed in this paper. The formulas calculating the height and the impact point of the steel ball are introduced and presented. Based to these formulas, the optimum section profiles of the basalt liner are presented.

• 대한기계학회논문집A
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• 제37권5호
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• pp.625-630
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• 2013

본 연구는 직경 45 nm인 원통형 나노동공을 가진 산화알루미늄(AAO) 박막에 오일을 함침시켰을때 동점도가 마찰 마멸에 미치는 영향을 규명하고자 실시하였다. 양극산화법으로 제조한 AAO 박막을 직경 1 mm의 440C 스테인리스 강구를 상대재로 하여 왕복동 미끄럼 접촉시험을 실시하였다. 마찰면과 마멸입자는 주사전자현미경과 에닥스(Energy-dispersive X-ray)를 이용해 분석하였다. 높은 동점도 오일의 윤활효과가 저점도 오일에 비해 크게 향상되었다. 동점도가 낮은 경우엔 모든 하중조건에서 심한 마찰흔적과 함께 두꺼운 소성변형층이 넓게 형성되었으며 경계윤활막의 손상으로 접촉면에 물질전이와 화학적 반응 현상이 모두 발생하였다. 오일의 점도가 높은 경우 마찰면에 존재하는 경계윤활막이 파괴되지 않아 마찰흔적과 소성변형층의 형성이 매우 적었으며 물질전이와 화학적 반응이 방지되었다.

• 복식
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• 제60권5호
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• pp.117-127
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• 2010

In this study, hyperspace is a result of imagination created by means of facts and fiction, represents a transfer to determination and indetermination, and means an extension to an open form. In other words, hyperspace is a high dimensional space expanded to imagination through the combination of the viewpoint on facts in this dimension and fiction. When the 2D plane surface or 3D symmetry is destroyed, or when the frame is twisted or entangled, the non-Euclidean geometry is created eventually. And when the twisting leads to transmutation and the destruction of the form reaches the extreme; this in turn became the twisting like Mbius band. Likewise, the non-Euclidean geometry is co-related to the asymmetry of the Higgs mechanism. When the 'destruction of symmetry' is considered, symmetric theory and asymmetric world can be connected. The asymmetry in turn can maintain balance by arranging the uneven weights at different distances from the shaft. Moreover, at this the concept of the upper, lower, left and right, which was included in the original form, may be crumbled down. The destruction of the symmetry is essential in order to present forecast that coincides with the phenomenon of the real world. Non-Euclidean geometry characteristic is expressed by asymmetry, twists, and deconstruction and its representative characteristic is ambiguity. The boundary between the front, back, upper, lower, inner and outer is unclear, and it is difficult and vague to pinpoint specific location. The design that does not clearly define or determine the direction of wearing costume is indeed the non-oriented design that can be worn without getting restricted by specific direction such as front and back. Non-Euclidean geometry characteristic of hyperspace have been applied to create new shapes through the modification of the substance from traditional clothing of the eastern world to modern fashion. The way of thinking in the 'hyperspace' that used to be expressed in the costumes of the east and the west in the past became the forum for unlimited creation.