• The korean journal of orthodontics
• /
• v.28 no.1 s.66
• /
• pp.135-142
• /
• 1998

The purpose of the present study was to evaluate the effect of incisor protrusion on the mucogingival parameters including the width of attached gingiva. Thirty-seven young adults with lower anterior crowding were selected for this study. From the study model, the degrees of relative and absolute protrusions were measured for each lower incisor. Clinical non height, the width of keratinized gingiva, probing depth and the width of attached gingiva were measured with digital vernier calipers and Florida Probe System. Through comparing the difference of the above measurements between protruded and non-protruded incisors, and correlation analysis between each measurement, following results were obtained: 1. The protruded incisor showed narrow width of keratinized and attached gingiva comparing to non-protruded incisor. 2. The protruded incisor showed greater clinical crown height comparing to non-protruded side while there was no difference in the probing depth between protruded and non-protruded side. 3. The difference in the width of attached gingiva between protruded and non-protruded incisors showed higher significance in the lateral incisor than in the central incisor. 4. The degree of relative protrusion showed higher correlation with the width of attached gingiva than the degree of absolute protrusion. 5. Clinical crown height showed higher correlation with the width of attached gingiva than the degree of protrusion.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.7
• /
• pp.1106-1115
• /
• 2021

In this study, a fin that controls ship stern flow was attached on stern hull of a 80k bulk carrier to improve resistance performance. The rectangular cross-sectional fin was attached at several locations on the hull, and angle to streamline was changed with constant length, breadth, and thickness. The resistance performance and wake on propeller plane of the hull with and without the fin were analyzed using model-scale computational fluid dynamics simulation. The analysis results were extrapolated to full-scale to compare the performance and wake of the full-scale ship. First, the fin changed path of bilge vortex that flowed into the propeller along the stern hull without the fin to transom stern. This change increased pressure of the stern hull and upper region of the propeller, so pressure resistance and total resistance of the hull were reduced - the nearer the fin location to after perpendicular (AP) and base line of the hull, the larger the reduction of the resistances. Second, nominal wake fraction of the hull with the fin was lower than that without the fin. This dif erence was in proportion to the angle of the fin, but the total resistance reduction was in proportion until a certain angle at which the reduction was maximum. The largest total resistance reduction was approximately 2.1% at 12.5% of length between perpendiculars from the AP, 10% of draft from the base line, and 14° with respect to the streamline.

• The korean journal of orthodontics
• /
• v.28 no.1 s.66
• /
• pp.99-111
• /
• 1998

The purpose of this study was to evaluate the positioning errors according to the method of bonding lingual brackets. Dental models of twenty orthodontic patients with malocclusion were selected for this study. The positioning errors were measured on each model that brackets were bonded to. Three different bonding methods were used. For the first method the bracket was bonded intimately to the lingual surface of the model. For the second method, the bracket was bonded intimately to the lingual surface after setting up using articulator. The passive bracketing, bonding the bracket ligated first to ideal archwire, was used after setting up as the last method. The results were as follows: 1. The brackets bonded without setting up showed greater angulation errors in the upper 1st premolar and the lower canine than those in other bonding methods. The brackets bonded without passive bracketing showed greater positioning errors in upper central incisor, lower 1st and End premolars. 2. The brackets bonded without setting up showed greater torque error in lower 2nd premolar than those in other bonding methods. The brackets bonded without passive bracketing showed greater torque errors in all upper teeth, lower 1st and 2nd premolars. 3. The brackets bonded without passive bracketing showed greater rotation errors between upper central incisors, lower central incisors, lower lateral and central incisor, lower canine and lateral incisor. 4. The brackets bonded without setting up showed greater in-out errors between upper canine and lateral incisor than those in other bonding methods. The brackets bonded without passive bracketing showed greater in-out errors between upper central incisors, upper central and lateral incisors, upper 1st and 2nd premolars, lower lateral and central incisors, lower canine and lateral incisor. These results suggest that there is a large amount of positioning error in lingual brackets even by an indirect bonding technique, and it may be reduced by passive bracketing.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.12 no.6
• /
• pp.109-118
• /
• 2008

Carbon fiber reinforced polymer(CFRP) can be bonded to the soffit of a concrete beam as a means of repairing and strengthening the beam. In such beams, materials, concrete and carbon fiber sheets, are different in coefficient of thermal expansion. Consequently, interfacial shear stresses can be increased and debonding failure may occur at the plate ends due to temperature rising. This paper presents a method of approximate closed-form solutions for the interfacial shear stresses and conducts a beam test to compare the numerical results. In case of temperature rising over $30^{\circ}C$, interfacial stress of 0.91MPa is occurred at the end of sheet. Therefore, using carbon fiber sheet for strengthening the concrete beam, it is necessary to consider the thermal effects and to evaluate the long time behavior of the concrete beam by temperature change.

• 전기의세계
• /
• v.46 no.5
• /
• pp.3-10
• /
• 1997

뇌파, 즉 뇌전도는 뇌에서 일어나는 전위의 변화를 기록하는 것이다. 이는 두개골의 두피에 전극을 부착하거나 뇌 표면 또는 뇌속에 전극을 삽입하여 기록할 수 있다. 종래에는 뇌파는 활동전위의 동기화와 통합의 결과로서, 어떤 피질 영역에서의 뉴론의 활동을 직접 반영하는 것이라고 생각되어 왔다. 그러나 EEG 활동에서 상당한 부분은 뉴론의 막전위에 기인하며, 특히 느린 시냅스 후 전위의 가중에 기인한다고 할 수 있다. 그렇지만 활동전위가 EEG에 전혀 공헌하지 않는 것은 아니다. EEG는 그 파형에 따라 동기화 또는 비동기화로 나눌 수 있는데, 그 근간을 이루는 뇌 구조물은 상이하다. 그리고 피질의 활동에서 유래한 EEG는 피질하 구조물에 의해서도 영향을 받는다. 이러한 EEG를 활용한 연구는 인간 정신 과정을 이해하는데 이바지하는 바가 클 것이다.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2001.05a
• /
• pp.240-243
• /
• 2001

괘도차량에 부착된 물분사추진기의 유동해석을 실험과 포텐셜해석 그리고 점성해석을 사용하여 그 결과를 비교하였다. 예인수조에서 여러 차량 전진속도에 대해서 임펠러 회전수를 조정하여 제트속도를 변화시키면서 덕트표면에서의 정압을 계측하였다. 이는 제트시스템의 효율을 추정하기 위함이고 관로를 통한 에너지분포를 알 수 있다. 점성유동해석을 위해 지배방정식은 비압축성 Navier-Stokes 방정식을 유한체적법을 사용하여 이산화하고 해석하였으며 난류영향은 표준 ĸ-$\varepsilon$난류모형을 사용하여 유동을 해석하고 실험결과 및 포텐셜 해석결과와 비교하였다.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 1984.10a
• /
• pp.62-65
• /
• 1984

The radiation characteristics of flanged parabolic antenna with microwave absorber are examined in order to reduce the backward scattered field. As a result, the unwanted radiation is suppressed and the wide angle radiation pattern from 100 is improved by about 10 - 18 dB in comparison with the ordinary antenna.

• The Bulletin of The Korean Astronomical Society
• /
• v.36 no.1
• /
• pp.32-32
• /
• 2011

파묻힌 성단 NGC1333은 광학영역에서는 성운이 별을 가리고 있어서 관측 연구가 힘든 천체이다. 이 연구에서는 광학영역이 아닌 근적외선영역의 관측 자료를 이용하여 NGC1333 내 전주계열(pre-main sequence) 변광성을 찾아내었다. 관측 자료는 2005년11월부터 2007년 10월까지 미국 버지니아대학 Fan mountain 관측소의 31인치 반사망원경에 부착된 근적외선 카메라 Fancam에서 얻어졌다. Stetson 변광 지수(Stetson, 1996)를 이용해 변광 여부를 정하였다. 별 탄생 지역에서의 등연령곡선 모형을 적용한 색-등급도를 그리고 등연령곡선과 소광 현상 보정을 이용해 각 별들의 질량을 추정하였다.

• Proceedings of the Korean Society of Fisheries Technology Conference
• /
• 2001.05a
• /
• pp.43-44
• /
• 2001

프레임에 그물감을 부착하여 구성되어 있는 가두리 시설은 파랑과 조류 등에 의해 유체력을 많이 받기 때문에, 만 입구 또는 외만에 설치하는 경우에는 작용 유체력에 의하여 이것을 계류하고 있는 계류삭이 절단되거나 고정용 닻이 끌리게 되며 프레임 끼리 서로 충돌함으로써 결국 구조물이 파손된다. 이와 같은 문제점을 해결하기 위해서는 파랑과 조류에 의해 발생되는 유체력에 충분히 견딜 수 있도록 시설물을 설계해야 한다. (중략)

• Journal of Technologic Dentistry
• /
• v.2 no.1
• /
• pp.31-33
• /
• 1980

의치(denture) 파절조각(fracture segment)의 조립을 정확하고 쉽게 부착시킬 수 있는 cyanoacrylate의 사용을 권장하고 싶다. 이 수리 방법은 환자가 오랜기간 동안 보철물 없이 존속하는 것을 막기 위해 석고모형(stone cast)을 부울 필요없이 신속하게 수리하는 방법이다. 더불어 의치(denture)가 많은 조각으로 파절 되었기 때문에 전통적인 방법에 의해서는 수리가 가능치 않다고 생각 될 경우에는 이 방법이 좋으리라 생각되어 소개하는 바 입니다.