• Animal Systematics, Evolution and Diversity
• /
• 제38권1호
• /
• pp.46-49
• /
• 2022

This study newly records a deep-sea coral, Flabellum (Ulocyathus) deludens from Korea. The specimens were collected by trawling at a depth of 100 m off Jejudo Island in 2019. The newly recorded species is described and compared with the other similar consubgeneric species in detail based on morphological characteristics, including corallum size, calicular diameter, calicular edge, face angle, edge angle, and septal arrangement. Flabellum(Ulocyathus) deludens is characterized by its solitary, highly compressed, wedge-shaped corallite with a small cylindrical pedicel, radiating inverse chevron-patterned lateral stripes on thecal faces, highly jagged calicular edges, and hexameral septal arrangement in five cycles. As a result of this study, five species in the family Flabellidae have been recorded from Korea.

• 한국재난정보학회 논문집
• /
• 제9권2호
• /
• pp.188-194
• /
• 2013

철도의 고속화가 진행됨에 따라 보다 경제적인 고속선용 교량 시스템의 개발을 위한 연구가 활발히 진행되고 있다. 이 논문에서는 기존의 프리스트레싱기법에 새로운 방식으로 추가적인 프리스트레스를 도입할 수 있는 바이프리스트레싱기법을 이용한 신형식 거더를 소개하였다. 추가적인 인장력은 단면 상부에 설치된 강봉 사이에 쐐기형 핀바를 삽입하여 도입할 수 있다. 신형식 거더가 적용된 철도교량의 고속선 적용성은 동적해석을 통한 안정성 검토를 통하여 수행하였다. 동적안정성 검토는 30m, 35m 및 40m 경간의 교량시스템에 대한 KTX 이동하중해석을 통하여 수행하였다. 검토 결과 개발된 교량은 구조적 안정성, 주행안전성, 승차감 확보를 위하여 검토되고 있는 제한값을 모두 만족하는 것으로 나타났다.

• Geomechanics and Engineering
• /
• 제24권5호
• /
• pp.457-470
• /
• 2021

In this study, the pull-out behavior of a tunnel-type anchorage for suspension bridges was investigated using experimental tests and image processing analyses. The study focused on evaluating the initial failure behavior and failure mode of the tunnel-type anchorage. In order to evaluate the failure mode of tunnel-type anchorage, a series of scaled model tests were conducted based on the prototype anchorage of the Ulsan Grand Bridge. In the model tests, the anchorage body and surrounding rocks were fabricated using a gypsum mixture. The pull-out behavior was investigated under plane strain conditions. The results of the model tests demonstrate that the tunnel-type anchorage underwent a wedge-shaped failure. In addition, the failure mode changed according to the differences in the physical properties of the surrounding rock and the anchorage body and the size of the anchor plate. The size of the anchor plate was found to be an important parameter that determines the failure mode. However, the difference in physical properties between the surrounding rock and the anchorage body did not affect its size. In addition, this study analyzed the initial failure behavior of the tunnel-type anchorage through image analysis and confirmed that the failure was sequentially transferred from the inside of the tunnel to the surrounding rock according to the image analysis. The reasonable failure mode for the design of the tunnel-type anchorage should be wedge-type rather than pull-out type.

• Wind and Structures
• /
• 제23권6호
• /
• pp.505-521
• /
• 2016

The objective of this study is to investigate numerically the effect of building roof shaps on wind flow and pollutant dispersion in a street canyon with one row of trees of pore volume, $P_{vol}=96%$. A three-dimensional computational fluid dynamics (CFD) model is used to evaluate air flow and pollutant dispersion within an urban street canyon using Reynolds-averaged Navier-Stokes (RANS) equations and the Explicit Algebraic Reynolds Stress Models (EARSM) based on k-${\varepsilon}$ turbulence model to close the equation system. The numerical model is performed with ANSYS-CFX code. Vehicle emissions were simulated as double line sources along the street. The numerical model was validated by the wind tunnel experiment results. Having established this, the wind flow and pollutant dispersion in urban street canyons (with six roof shapes buildings) are simulated. The numerical simulation results agree reasonably with the wind tunnel data. The results obtained in this work, indicate that the flow in 3D domain is more complicated; this complexity is increased with the presence of trees and variability of the roof shapes. The results also indicated that the largest pollutant concentration level for two walls (leeward and windward wall) is observed with the upwind wedge-shaped roof. But the smallest pollutant concentration level is observed with the dome roof-shaped.

• Journal of Periodontal and Implant Science
• /
• 제34권3호
• /
• pp.647-657
• /
• 2004

A non-carious cervical lesion(NCCL) is the loss of tooth structure at the cementoenamel junction level that is unrelated to dental caries. This study was to evaluate the occlusal and periodontal status of teeth with non-carious cervical lesions. We evaluated 105 teeth with non-carious cervical lesions in 35 subjects aged 38-75 years and characterized them based on the shape and dimension, plaque retention, bleeding on probing(BOP), probing pocket depth(PPD), occlusal status, brushing type, hypersensitivity and wear facet. The results of this study were as follows 1. No significant association was observed between cervical lesions and occlusal contact in lateral excursions. 2. No significant difference occurred in plaque retention, PPD, BOP between teeth with and without cervical lesions. 3. Test teeth had a significantly higher percentage of hypersensitivity and occlusal wear facet than teeth without cervical lesions. 4. Wedge shaped lesions had a significantly higher percentage of plaque than saucer shaped lesions. 5. Teeth with plaque were found to have significantly deeper PPD than teeth without plaque retention in cervical regions. 6. Teeth with occlusal contacts were found to have significantly deeper PPD than teeth without occlusal contacts. 7. No significant association was observed between cervical lesions and PPD independent of plaque retention and occlusal contacts Although more knowledge is necessary, our results suggest that occlusal contact and bacterial plaque may influence on periodontal tissue, but NCCL is not directly associated with periodontal health

• 한국지반공학회지:지반
• /
• 제5권1호
• /
• pp.47-60
• /
• 1989

본 논문에서는 사질토를 뒷채움한 강성연직벽에 작용하는 횡토려의 분포를 유한요소법을 이용한 탄소성해석에 의하여 구하고 벽체의 3가지 변위형태(벽체정부중심회전, 벽체양부중심회전및 평행이 동형태 및 변위의 크기가 토압분포에 미치는 영향을 연구하였다. 그리고 이들 토압을 Rankine주동 토압 및 Dubrova주동토압과 비교하였다. 벽달정부중심회전하는 경우 아아칭효과에 의하여 역5-형토려분포를 나타내고 결과적으로 벽체 전 높이에 작용하는 총토추의 작용점은 벽체람부로부터 벽체높이의 113보다 훨씬 높을 뿐만 아니라 다 른 형태의 벽체변위에 비하여 제일 높고 또한 크기도 가장 크다. 그리고 벽체변위가 증가하여 주동상태로 파괴될 때 뒷채움지반내에 발달하는 소성영역은 벽체저부중심회전형태인 경우에만 쐐기형태로 발달하고 다른 변위형태의 경우에는 쐐기형태를 보이지 않는다. 또한 뒷채움이 경사지면인 경우 몇가지 경사도에 대한 저부중심회전벽체의 토압분포를 나타내었다.

• Ocean Science Journal
• /
• 제42권4호
• /
• pp.231-240
• /
• 2007

Three marine fish species are recorded for the first time from Korean waters: a molid (Ranzania laevis, 1 specimen, 279.8 mm SL) and bramid (Pterycombus petersii, 3 specimens, 95.3-214.0 mm SL) collected from a large purse seine off Jeju Island, in the southern sea of Korea, and a carangid (Carangoides dinema, 1 specimen, 194.5 mm SL) from a set net in coastal waters off Busan, in the southeastern sea of korea. R. laevis is characterized by a wedge-shaped body and truncated clavus; P. petersii by the dorsal fin origin above or behind the posterior margin of eye, and dorsal and anal fins depressible; and C. dinema by a row of black blotches along the second dorsal fin base, the curved part of the lateral line longer than straight part, and 18 and 16 dorsal and anal fin rays, respectively. New Korean names are proposed for all three species.

• Archives of Plastic Surgery
• /
• 제45권6호
• /
• pp.572-577
• /
• 2018

Background Mandibular contouring surgery to produce a more slender and small face has become popular, especially in East Asia. Narrowing genioplasty should be simultaneously performed with mandibular angle resection to achieve satisfactory results. In Korea, T-genioplasty has been frequently performed for chin narrowing. The authors developed a new, safe, and reliable method, termed M-genioplasty, that can provide a more slender and attractive lower face. Methods From June 2013 to December 2017, 36 patients underwent M-genioplasty with mandibular angle resection for lower facial contouring. Horizontal and vertical osteotomies were performed obliquely. The resected bone segments were wedge-shaped. The remaining two bone segments were rotated and approximated centrally. The lateral mandible bony step-off was trimmed off for mandibular angle resection. Results In all patients, the facial contour sufficiently improved, and most patients were satisfied with the outcome. No severe complications took place during postoperative follow-up. Conclusions M-genioplasty can provide more mandibular angle resection and can create a more acute chin angle without bone resorption than other methods, including T-genioplasty. M-genioplasty with mandibular angle resection is a safer, more accurate, and more reliable method for lower facial contouring.

• 한국기계가공학회지
• /
• 제19권8호
• /
• pp.35-42
• /
• 2020

In discharge machining, material is removed by electrical discharge between the electrode and the workpiece. An important consideration in EDM is that the wear of the electrodes decreases the final precision of the workpiece. The edge wear of the electrodes proceeds very quickly because sparks occur more frequently at the edges with high local electrical strength. In this study, mold steel was discharged with a wedge-shaped graphite electrode to measure the edge wear of the electrode according to the depth. The electrode edge wear increased with depth during EDM and a wear model was developed. The model predicted that the edge wear can be reduced by approximately 70% using two electrodes instead of a single electrode. The model was supported by the experimental comparison of the dual electrode method and the single electrode method.

• Geomechanics and Engineering
• /
• 제5권3호
• /
• pp.241-261
• /
• 2013

The bearing mechanism of pile during installation and loading process which controls the deformation and distribution of strain and stress in the soil surrounding pile tip is complex and full of much uncertainty. It is pointed out that particle crushing occurs in significant stress concentrated region such as the area surrounding pile tip. The solution to this problem requires the understanding and modeling of the mechanical behavior of granular soil under high pressures. This study aims to investigate the sand behavior around pile tip considering the characteristics of sand crushing. The numerical analysis of model pile loading test under different surcharge pressure with constitutive model for sand crushing is presented. This constitutive model is capable of predicting the dilatancy of soil from negative to positive under low confining pressure and only negative dilatancy under high confining pressure. The predicted relationships between the normalized bearing stress and normalized displacement are agreeable with the experimental results during the entire loading process. It is estimated from numerical results that the vertical stress beneath pile tip is up to 20 MPa which is large enough to cause sand to be crushed. The predicted distribution area of volumetric strain represents that the distributed area shaped wedge for volumetric contraction is beneath pile tip and distributed area for volumetric expansion is near the pile shaft. It is demonstrated that the finite element formulation incorporating a constitutive model for sand with crushing is capable of producing reasonable results for the pile loading problem.