• Title/Summary/Keyword: Sharp margin

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THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS OF STRESS DISTRIBUTION IN ALL-CERAMIC CROWNS WITH VARIOUS FINISH LINE DESIGNS AND INCISAL REDUCTIONS UNDER DIFFERENT LOADING CONDITIONS (전부 도재관을 위한 지대치의 마무리선 형태와 절단연 삭제량 및 교합력 작용점에 따른 응력 분포에 관한 삼차원 유한요소법적 연구)

  • Koh, Eun-Suk;Lee, Sun-Hyang;Yang, Jae-Ho;Chung, Hun-Young
    • The Journal of Korean Academy of Prosthodontics
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    • v.35 no.4
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    • pp.742-766
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    • 1997
  • The purpose of this study was to determine the effect of finish line design, amount of incisal reduction, and loading condition on the stress distribution in anterior all-ceramic crowns. Three-dimensional finite element models of an incisor all-ceramic crown with 3 different finish line designs : 1) shoulder with sharp line angle 2) shoulder with rounded line angle 3) chamfer : and 2 different incisal reductions : 2mm and 4mm were developed. 300 N force with the direction of 45 degree to the long axis of the tooth was applied at 3 different positions : A) incisal 1/3, B) incisal edge, C) cervical 1/5. Stresses developed in ceramic and cement were analyzed using three-dimensional finite element method. The results were as follows : 1. Stresses were concentrated in the margin region, which were primarily compressive in the labial and tensile in the lingual. 2. Stresses were larger in the area near line angle than on the crown surface of the margin region. In case of shoulder with sharp line angle, stresses were highly concentrated in the porcelain near line angle. 3. At the interface between porcelain and cement and at the porcelain above the margin on crown surface, stresses were the highest in chamfer, and decreased in shoulder with sharp line angle and shoulder with rounded line angle, respectively. 4. At the interface between cement and abutment on crown surface, stresses were the highest in shoulder with sharp line angle, and decreased in shoulder with rounded line angle and chamfer, respectively. 5. The amount of incisal reduction had little influence on the stress distribution in all-ceramic crowns. 6. When load was applied at the incisal edge, higher stresses were developed in the margin region and the incisal edge than under the other loading conditions. 7. When load was applied at the cervical 1/5, stresses were very low as a whole.

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A Report of Carcinus aestuarii (Decapoda: Brachyura: Carcinidae) from Korea

  • Lee, Sang-kyu;Lee, Sang-Hui;Kim, Hyun Kyong;Song, Sung Joon
    • Animal Systematics, Evolution and Diversity
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    • v.36 no.4
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    • pp.420-423
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    • 2020
  • As a result of continuous taxonomic studies on the Korean crabs, Carcinus aestuarii Nardo, 1847 belonging to the superfamily Portunoidea is newly reported from Korean waters. Carcinus aestuarii has characteristics as followings: cardiac, hepartic and brachial regions are divided by deep furrow; shape of three lobes in frontal area is flatter with hairy; inside of carpus is with one sharp tooth; the posterior-lateral margin of the carapace is concave, and so on. The examined specimen doesn't have hairy and bump on outer margin of the chelipeds which differed from the previous description of the specimens collected from Tokyo Bay, Japan. Here, the diagnosis and the picture of Korean specimen is provided. Korean portunoids currently consist of 20 species belonging to 10 genera.

Two Omaliine Species (Coleoptera: Staphylinidae) New to Korea

  • Kim, Tae-Kyu;Ahn, Kee-Jeong
    • Animal Systematics, Evolution and Diversity
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    • v.30 no.2
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    • pp.151-157
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    • 2014
  • A taxonomic study of two omaliine genera Acruliopsis Zerche and Omalium Gravenhorst in Korea is presented. Two species (Acruliopsis ussuriensis Zerche and Omalium japonicum Sharp) are reported for the first time in Korea. Diagnoses of those two genera with redescriptions of the species are presented. Acruliopsis ussuriensis is distinguished by more or less short elytra, a pair of conspicuous processes on male sternite VII and emargination of outer lateral margin of paramere at base. Omalium japonicum is distinguished by brown elytra and structure of aedeagus with swollen median lobe and expanded paramere. Habitus photographs and illustrations of diagnostic characters are provided.

Muller's Muscle-Levator Aponeurosis Advancement Procedure for Blepharoptosis (뮐러근과 거근건막의 전진술에 의한 안검하수의 교정)

  • Baik, Bong Soo;Kim, Tae Bum;Hong, Wang Kwang;Yang, Wan Suk
    • Archives of Plastic Surgery
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    • v.32 no.2
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    • pp.219-226
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    • 2005
  • Muller's muscle-levator aponeurosis advancement procedure was performed to correct mild to moderate congenital blepharoptosis with moderate to good levator function and to correct severe aquired blepharoptosis with poor levator function. Through the blepharoplasty incision, the upper half of the tarsal plate was exposed and the orbital septum was opened to show the levator aponeurosis. The Muller's muscle was dissected from the superior margin of the tarsal plate and from the posteriorly located conjunctiva with sharp scissors. The Muller's muscle and levator aponeurosis were advanced on the anterior surface of the tarsal plate as a composite flap and fixed approximately 3 to 4 mm inferior to the upper edge of the tarsal plate with three horizontal 6-0 nylon mattress sutures. The amount of advancement of the composite flap was controlled by the location of the upper eyelid margin 2 mm below the upper limbus in primary gaze after the first suture in the middle portion of the flap. The excess flap was trimmed off with scissors, but trimming was usually not necessary in cases of mild to moderate ptosis. Nine cases underwent this Muller's muscle-levator aponeurosis advancement procedure from September 2003 to September 2004. Five cases were congenital blepharoptosis with 2-4 mm ptosis and more than 5 mm of levator function, but three of the four acquired ptosis cases had more than 4 mm ptosis with poor levator function. The age of the patients ranged from 7 to 81 years. In operative results, all patients except one traumatic case were within 1 mm of the desired eyelid height in primary gaze. This procedure can provide not only tightening of the Muller's muscle but also advancement and firm fixation of the levator aponeurosis to the tarsal plate, yielding predictable results.

A Treatment Case of Delayed Aortic Injury: The Patient with Posterior Rib Fracture

  • Park, Hyun-Seok;Ryu, Se-Min;Cho, Seong-Joon;Park, Sung-Min;Lim, Sun-Hye
    • Journal of Chest Surgery
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    • v.47 no.4
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    • pp.406-408
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    • 2014
  • A 66-year-old male patient arrived at the emergency room with a crush injury to his chest. Multiple rib fractures, hemothorax on both sides, left scapular fracture, liver laceration, and retroperitoneal hematoma were found upon the radiologic examination. After closed thoracostomy, the patient had been initially admitted to the intensive care unit, but he was transferred to the general ward on the next day. On the 4th post-trauma day, the patient complained of severe pain and there was bloody drainage through the chest tube. This case is an exploration with the consideration of the possibility of major bleeding and the subsequent repair of the descending thoracic aorta. This case is regarded as a case in which the aorta wall was damaged as the sharp margin of the fractured ribs caused continuous irritation.

Photoelastic Determination of Stress Intensity Factors by Teflon Molding Method - Evaluation of The Method In Terms of Two Dimensional Mode I and Mode II - (테프론 모울딩법 에 의한 S .I .F.의 광탄성 실험해석 - 이차원 S .I .F. 문제에 대한 실험방법 의 정도평가 -)

  • 최선호;황재석;채영석
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.7 no.1
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    • pp.1-10
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    • 1983
  • The photoelastic determination of S.I.F. in Fracture mechanics has been regarded as one of the most effective and practical experimental methods in which stresses are read directly, except a few shortcomings involved in the process of experiment; the difficulties of making a sharp crack tip similar to the practical one and nearly impossibilities of carving an arbitrarily shaped crack on the test plate, etc. To eliminate flaws mentioned above, recently, Kitagawa and Watanabe of Tokyo Univ.developed a new method named"Teflon Insert Method". which has improved experimental accuracy to a considerable extent byt remaining still room for further improvement, that is, the elimination of bonding boundary scars which render photoelastic fringes obscure. In this paper, a newly exploited"Teflon Molding Method" was attempted for the completion of teflon-epoxy experimental method. The experimental results obtained by this method are compared with existent theoretical and experimental values to evaluate its accuracy. As result, 1-6% of margin of errors were appeared in a series of photoelastic experiments which defied any other conventional method in terms of experimental accuracy.perimental accuracy.

Ventricular Septal Defect by Penetrating Chest Trauma - Report of One Case - (관통성 흉부 자상에 의한 심실중격 결손증: 증례보고)

  • Kim, Mun-Hwan;Lee, Cheol-Ju
    • Journal of Chest Surgery
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    • v.25 no.4
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    • pp.429-434
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    • 1992
  • We experienced a rare case of traumatic ventricular septal defect by penetrating stab injury The patient was 26-year-old women who got stab wound at the left anterior third intercostal space and left sternal border with a knife. seven hours after admission, the patient was undertaken an emergency thoracotomy due to hypovolemic shock caused by massive bleeding from transected left internal mammary artery, vein, and right ventricular outflow tract. On postoperative second day, the patient was suffered from moderate dyspnea, and arterial blood gas analysis and chest X-ray revealed hypoxemia and pulmonary edema. Right heart cardiac catheterization with Swan-Ganz Cathater showed oxygen step-up between right atrium and main pulmonary artery and a 1.6:1 ratio of pulmonary to systemic blood flow. At operation, harsh systolic thrill was palpable along right ventricular outflow tract. Through small vertical right ventriculotomy, the linear ventricular septal laceration on infundibular septum was noticed, and its size was 1.5cm with sharp margin This defeat was repaired by three interrupted matress sutures using Prolene 4-O with pledget. Her postoperative course was uneventful, and she discharged with good physical condition.

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Minimally Invasive Surgery for Hallux Valgus Deformity Using Intramedullary Low Profile Plate Fixation: A Case Report (소형 금속판의 골수강 내 고정을 통한 최소 침습적 무지 외반증 교정 수술: 증례 보고)

  • Cho, Sung Tan;Suh, Jin Soo;Choi, Jun Young
    • Journal of Korean Foot and Ankle Society
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    • v.23 no.3
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    • pp.135-138
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    • 2019
  • According to a recent systemic review, hallux valgus deformity has a prevalence rate of about 23% among adults aged 18 to 65 years. To date, more than 100 operative methods have been reported for the correction of hallux valgus deformity. For young female with mild to moderate hallux valgus deformity, minimally invasive surgery can be considered for aesthetic demands. Here, we report a case of a young female patient with mild hallux valgus deformity treated by minimally invasive surgery using intramedullary low profile plate fixation. This can be the favorable method for secure fixation of the osteotomy site and prevention of medial skin irritation symptoms derived from a sharp osteotomy margin.

Development of 3D Measuring System for Artificial Pontic using Spherical Coordinate System Mechanism (구면좌표계식 기구를 이용한 인공치아의 3차원 측정시스템 개발)

  • Maeng, Hee-Young;Sung, Bong-Hyun
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.19 no.4
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    • pp.427-433
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    • 2010
  • With recent increased demand for reverse engineering in dental machining, the 3D laser scanner is widely used for inspection of artificial pontic. In order to overcome the optical drawback of laser scanner, such as irregular scatter, direction of beam, and the influence of surface integrity, it is developed in this study a new 3D measuring system for artificial pontic using spherical coordinate system mechanism by point laser sensor, which keeps the direction of beam normal to surface consistently. The comprehensive integrated system is established to evaluate the improvement of accuracy with data acquisition system. The experimental results for measuring a master ball and pontic models shows the excellent form accuracy and repeatability compared with conventional apparatus. Also, these results shows the possibility to apply this system for the measuring purpose within 0.05mm accuracy of pontic at the sharp edge or margin contour, which was difficult to measure at the conventional systems.

The Physical Penumbra of the 6MV X-ray (6MV 방사선의 물리학적 Penumbra)

  • Cho Moon-June;Kang Wee-Saing
    • Radiation Oncology Journal
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    • v.9 no.2
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    • pp.333-336
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    • 1991
  • High energy Photon beam has a sharp beam margin due to a less side scatter and the other things. But there still remains a penumbra where the dose changes rapidly in the region near the edge of a radiation beam, although it is short in width. It is suggested that the width of the penumbra depends on the source size, distance from source to diaphragm, source to skin distance, and depth in tissue. However, it is also supposed that the other factors influence the penumbra width. In this paper, we investigate changes of the physical penumbra widths according to various field sizes and depths, by using the three dimensional dosimetry system. As a result, we found that as field size and depth increase, the physical penumbra width also increases.

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