• Tribology and Lubricants
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• 제12권4호
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• pp.13-17
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• 1996

립실의 중요 설계 변수인 접촉력의 측정에는 스플릿트축장치가 흔히 사용된다. 축과 립실의 간섭량은 두 개 스플릿트축의 간격으로서 조절된다. 두 축을 초기 위치로부터 측정하고자 하는 임의 위치로 이동시킬 때 정확한 원을 이루지 못해 측정되는 접촉력은 오차를 포함되게 된다. 본 연구에서는 작은 간섭량 범위 내에서 접촉력을 이론적으로 예측할 수 있는 수식을 유도하고 측정 오차 값을 예측하였다. 측정된 립실의 접촉력은 측정 간섭량이 초기간섭량과 일치하는 경우 외에는 항상 오차를 포함하고 있음을 밝혔다. 이 오차는 작은 간섭량 범위 내에서 립실의 재료 특성이나 형상에 무관하며, 10% 이내의 측정 오차 유지를 위해서는 측정 간섭량이 초기 간섭량의 68%에서 187% 범위 내에 들어야 함을 확인하였다.

• Tribology and Lubricants
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• 제10권2호
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• pp.39-42
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• 1994

This paper deals with the distributions of the contact stress in oil seals. The distributions of the contact stress due to the temperature effects are analyzed for various values of the interference for a nitrile rubber seal. The calculated FEM results show that the relative maximum stresses occur at the contacting area against the shaft, the flex zone, and the contacting area of the garter spring grooves. Using the coupled temperature-stress FEM a nalysis, the contact force of a radial lip seal with and without the garter spring are studied as a function of shaft diameter. The calculated results of mechanical analysis show good correspondence with those of the coupled thermal-mechanical analysis method except small values of the interference. And the calculated results indicated that the thermal stresses only have a very minor influence on the deformed shape of the lip seal as the interference increases. But the coupled temperature-stress analysis will be very useful tool to predict the contact behaviors of rubber lip seals for small values of the interference.

• 대한구순구개열학회지
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• 제7권2호
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• pp.107-121
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• 2004

Midface and maxillary distraction osteogenesis (DO) can be an alternative treatement modality for the craniofacial syndrome patients and cleft lip and palate patients. Rigid External Distraction (RED) II system has more advantages in the force vector control than the other types of distraction systems. Despite of increasing popularity of RED system there is few report on the failure factors. Some considerations should be pointed out in using RED II system for successful treatment; the rigidity of intraoral splint, complete separation of bony segment, and the cooperation of patients. Orthodontists, surgeons, and patients have the same amount of responsibility for the successful midface and maxillary DO using RED II system from the beginning to the end of the treatment.

• 대한기계학회논문집
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• 제14권1호
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• pp.119-129
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• 1990

본 연구에서는 선적분화 된 체적력항을 갖는 경계요소법을 이용하여, Griffi- th균열에 대한 열응력세기계수를 구하여 Sumi의 결과와 비교 검토하고, 유무한체내의 대칭 입술형및 대칭 익형 커스프균열들(symmetric lip and airfoil cusp cracks)의 열 응력세기계수를 균열묘면이 단열된 경우와 일정 온도로 유지된 경우에 대해 계산하고 자 한다.

• 대한치과교정학회지
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• 제21권2호
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• pp.287-307
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• 1991

This study aimed at examining speech defects of openbite patients, which were analized in terms of formant frequency for vowels and word pronunciation length for consonants. In addition, the upper and lower lip (perioral m.) activity was tested by the EMG. The tongue force was measured by the strain gauge, and the speech discrimination test was carried out. One experimental group and one control group were used for this study and they were respectively composed of six female openbite patients and six normal-occlusion females. Eight monophthongs, two fricatives and two affricatives were chosen for speech analysis. Speeches of the above-mentioned groups were recorded and then analized by the ILS/PC-1 software. Four hundred most frequently used monosyllables were also chosen for discrimination score. Openbite patients showed the following characteristics: 1. Abnormality in case of /a/, $/\varepsilon/$, /e/, /i/ $F_2$ and /e/, /a/ $F_1$. 2. Significantly elongated length in their pronunciation of /h/ and $/C^h/$ and somewhat elongated length also in their pronunciation of /s/ and /c/. 3. Significant upper lip activity according to the EMG test during pronunciation of the bilabial consonants. 4. Relatively weak tongue force according to the strain gauge measurement. 5. According to the speech discrimination test, high rate of misarticulation in case of (a) initial /p/ /s'/ and /ts'/, (b) /a/,$/\varepsilon/$,/e/,/je/,/o/, $/\phi/$,/jo/,/u/,/we/, and /i/ (c) final (equation omitted).

• 대한구순구개열학회지
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• 제16권1호
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• pp.1-8
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• 2013

Purpose : To introduce a more effective and efficient protocol for protraction of maxillary complex in CLP patient and demonstrate it by case presentation. Methods : Miniplates are placed on zygomatic buttress and anterior part of mandible, at the time of secondary alveolar bone graft. During the night time, the orthopedic force is applied by wearing elastics from maxillary miniplates to facemask (500 g per side). During the day time, the intermaxillary elastics connecting maxillary miniplates to mandibular miniplates are applied (200 g per side). During the orthopedic treatment, dental alignment is possible. Results and conclusion : By the new protocol, the intermaxillary relation and occlusion are improved due to the stable intraoral anchorage and better cooperation of patients.

• 대한치과교정학회지
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• 제19권3호
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• pp.147-160
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• 1989

Long face patients are characterized by excessive anterior facial height, lip incompetence at rest, anterior open bite, and gummy smile. A major problem is an inferior rotation of the posterior maxilla and upper molars. Long face patients have been the most difficult for orthodontist to treat successfully. In growing patients, the methods for impeding excessive vertical growth have been used high pull head gear, functional appliance, and combined type of two. One significant improvement comes from using a full arch splint to deliver force to the maxilla more vertically. In adult patients, orthodontic camouflage treatment is biomechanically difficult and doesn't work when the problem is primarilly vertical. Surgical maxillary impaction provides a means for successfully treating most of problems. Also, superior reposition of the chin via a mandibular inferior border osteotomy is effective in decrease of lower anterior facial height and correction of the poor chin-lip balance. Post-surgical stability and the physiologic response are good. The coordinated orthodontic and surgical treatment is necessary for solution the difficult skeletal deformity.

• 대한치과교정학회지
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• 제51권6호
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• pp.428-434
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• 2021

Craniofacial clefts are extremely rare deformities. Tessier's classification is a widely accepted system that is based on clinical, radiographical, and surgical observations. The Tessier No. 0 cleft most commonly affects the upper lip, nose, and palate. This case presentation aims to report the outcome of a modified presurgical alveolar molding (PAM) appliance used in the treatment of an infant with Tessier No. 0 cleft as an alternate approach to mold such defects before surgery. The modified PAM appliance consisted of reciprocal parts connected by a helix. The segments were approximated by stripping the appliance at the midline in a V-shaped manner and the force was exerted by the extraoral elastics. The procedure gave results in 8 weeks, which may be regarded as a reasonable duration. The anterior cleft gap, which was 13 mm before the treatment, was reduced to 3 mm after the treatment by using modified PAM appliance. On a 21-month follow-up period, oral reshaping was regarded successful due to stability of the improved oral mold.

• 대한치과교정학회지
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• 제50권4호
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• pp.290-290
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• 2020

• 구강회복응용과학지
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• 제33권4호
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• pp.284-290
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• 2017

구순구개열 환자에게 가철성 보철치료는 중요한 치료 선택 중 하나이다. 구순구개열 환자에서 만족스러운 기능적 및 심미적 결과를 얻기 위해서는 전통적인 보철 치료법에서 약간의 수정이 필요할 수 있는데, 치주 질환에 이환되어 있으며 소수의 구치만 잔존해 있는 구개열 환자의 경우 이중관에 연결된 가철성 보철이 치료 선택의 대안이 될 수 있다. 이중관이 가철성 국소의치에 연결되면 보철적 안정성과 유지를 증가시키고 치아 장축에 유리한 힘 전달을 최적화하며 심미성도 향상시킨다. 그리고 이중관 의치의 횡단치열궁안정(cross arch stabilization)은 구순구개열 환자의 갈라진 치조제의 안정화에도 도움을 준다. 본 증례는 성인 구순구개열 환자에서 마찰핀(friction pin)을 사용한 혼성 이중관 가철성 국소의치를 제작하여 유지 및 안정성과 함께 심미성도 향상시켜 만족할 만한 결과를 나타낸다.