• 대한치과보철학회지
• /
• 제35권4호
• /
• pp.674-696
• /
• 1997

There're many cases that should be reconstructed with post and core when clinical crown is destructed. But this post and core restoration may cause damaging stress on the teeth. Previous finite element study was restricted to normal bone model relatively close to cemen-toenamel junction. Moreover, the test of a model with diminished bone support was rare. The purpose of this study is to test the effects of alveolar bone loss on the magnitude, stress distribution and displacement of post reconstructed teeth. In this study, it was assumed that the coronal portion of upper incisor was severely destructed. After conventional endodontic treatment, it was restored with post and core. The PFM restoration was made on it. This crown was cemented with ZPC. Alveolar bone was classified by 4 types of bone, such as normal, 2 mm, 4 mm, 6 mm bone, according to the bone loss. Meanwhile, the material of post are divided into 2 types of materials, such as gold, co-cr. Force was applied to two directions. One was fuctional maximum bite force (300 N) applied to the spot just lingual to the incisal edge with the angle of 45 degree to the long axis of the tooth, and the other one was horizontal force (300 N) applied to the labial surface. The results analyzed with three dimensional finite element method were as follows : 1. Stress was concentrated on the adjacent dentin of the post apex, one third portion of the post apex and the labial & lingual mid-portion of the root in all case. The stress of middle third of the root was apparently concentrated on the labial aspect. 2. The stress on adjacent dentin of the post apex and one third of the post apex increased as alveolar bone height moved apically. This increase was dramatic beyond 4 mm bone loss model. 3. The stress of the post apex was spreaded to the middle third of the post and greater than gold post in the case of metal post. 4. The displacement of the neck of post was the greatest in one of the post-cement interface and this increased as alveolar bone height moved apically. Besides the displacement of the metal post is slightly lower than one of the gold post.

• 한국화재소방학회논문지
• /
• 제27권5호
• /
• pp.75-79
• /
• 2013

임신부의 경우 심폐소생술동안 좌측 기울림을 적용하도록 권장하고 있다. 하지만, 이 좌측으로 기울리면 임신부의 자궁 뿐만이 아니라 좌심실도 좌측으로 편위되어 심폐소생술의 심장펌프기능이 떨어질 가능성이 있다. 이에 좌측 기울림이 심폐소생술동안 흉골 운동 방향을 대변하는 전후축과 좌심실의 공간적 관계에 미치는 영향을 알아보고자 하였다. 컴퓨터 단층촬영을 이용한 가상내시경검사를 받은 90명의 환자를 대상으로 의무기록과 컴퓨터단층촬영결과를 후향적으로 조사하였다. 가상내시경은 앙와위와 좌측 기울림 위치 모두에서 실시되었다. 좌심실 단면적이 가장 넓은 축면에서 전후축과 좌심실축사이의 각도($Angle_{AP-LV}$), 전후축과 좌심실 중앙사이 최단거리($D_{AP-MidLV}$), 및 전후축과 좌심실첨부사이 최단거리($D_{AP-Apex}$)를 측정하였다. 대상환자 중 87명(96.7%)에서는 앙와위에서 좌심실이 전후축의 좌측에 위치하였다. 좌측으로 기울인 영상에서의 기울림 각도는 $43.4{\pm}11.0^{\circ}$였다. $D_{AP-MidLV}$와 $D_{AP-Apex}$는 좌측 기울린 위치에서 의미있게 길었지만 (p<0.001), AngleAP-LV는 두 자세 사이에 비슷했다. 심장정지인 임신부에서 좌측으로 기울림은 흉부압박의 심장펌프 효과를 떨어뜨릴 수도 있다.

• 한국농공학회논문집
• /
• 제63권6호
• /
• pp.1-16
• /
• 2021

Global warming due to climate change is expected to significantly affect the hydrological cycle of agriculture. Therefore, in order to predict the magnitude of climate impact on agricultural water resources in the future, it is necessary to estimate the water demand for irrigation as the climate change. This study aimed at evaluating the future changes in water demand for irrigation under two Shared Socioeconomic Pathways (SSPs) (SSP2-4.5 and SSP5-8.5) scenarios for paddy rice in Gimje, South Korea. The APEX-Paddy model developed for the simulation of paddy environment was used. The model was calibrated and validated using the H₂O flux observation data by the eddy covariance system installed at the field. Sixteen General Circulation Models (GCMs) collected from the Climate Model Intercomparison Project phase 6 (CMIP6) and downscaled using Simple Quantile Mapping (SQM) were used. The future climate data obtained were subjected to APEX-Paddy model simulation to evaluate the future water demand for irrigation at the paddy field. Changes in water demand for irrigation were evaluated for Near-future-NF (2011-2040), Mid-future-MF (2041-2070), and Far-future-FF (2071-2100) by comparing with historical data (1981-2010). The result revealed that, water demand for irrigation would increase by 2.3%, 4.8%, and 7.5% for NF, MF and FF respectively under SSP2-4.5 as compared to the historical demand. Under SSP5-8.5, the water demand for irrigation will worsen by 1.6%, 5.7%, 9.7%, for NF, MF and FF respectively. The increasing water demand for irrigating paddy field into the future is due to increasing evapotranspiration resulting from rising daily mean temperatures and solar radiation under the changing climate.

• 한국안광학회지
• /
• 제16권3호
• /
• pp.273-281
• /
• 2011

목적: RGP 렌즈의 디자인 개발 및 처방을 위한 기초자료를 제공하고자 20대의 각막 형상을 형태별, 난시도별, 각막 정점으로부터의 거리별로 분석하였다. 방법: 각막 지형도 검사(corneal topography)를 이용하여 20대 총 252안의 각막형태를 분류하고 각막 정점으로부터 일정 간격 내의 각막곡률반경을 측정한 후 난시도에 따라 비교 분석하였다. 결과: 20대의 각막형태는 원형 14.3%(36안), 타원형 31.3%(79안), 대칭 나비형 28.6%(72안), 비대칭 나비형 17.5%(44안), 부정형 8.3%(21안)로 분류되었다. 원형 및 타원형 각막은 각막난시도가 낮은 경우가 많은 반면 대칭 나비형 및 비대칭 나비형 각막은 높은 경우가 많았다. 각막 정점에서 일정 간격으로 각막곡률반경을 측정하였을 때 원형 및 타원형 각막에서는 각 구간별로 상대적인 각막곡률반경이 난시도와 상관없이 모두 일관되게 증가하는 양상을 보였다. 대칭 나비형 및 비대칭 나비형 각막에서는 각막 정점으로부터 반경 1.0-1.5 mm 범위의 상대 각막 곡률반경이 감소하여 반경 1.0 mm 이내보다 오히려 급경사를 이루었으며 이러한 양상은 난시도에 따라 차이가 있었다. 난시도 1.50-2.00 D 및 2.25-2.75 D의 나비형 각막에서는 반경 3.5 mm부터 각막 곡률의 변화가 더 심하게 나타났다. 결론: 각막 형상 및 난시 정도에 따라 각막 중심부에서 주변부로의 각막곡률반경의 변화 정도가 달라짐을 보이므로 RGP 렌즈의 제조 및 처방시 이에 대한 고려가 필요하리라 여겨진다.

• 기술사
• /
• 제36권4호
• /
• pp.62-67
• /
• 2003

• 대한치과보존학회:학술대회논문집
• /
• 대한치과보존학회 2004년도 춘계 학술대회 (제121회) 초록집
• /
• pp.315-317
• /
• 2004

• 대한치과보존학회:학술대회논문집
• /
• 대한치과보존학회 2003년도 춘계학술대회
• /
• pp.267-270
• /
• 2003

• 대한장애인치과학회지
• /
• 제3권2호
• /
• pp.97-100
• /
• 2007

In patients with cerebral palsy, dental treatments, which require absolute patient's corporation, have many difficulties because of muscle spacity, involuntary muscle movements and spasm. Especially in endodontic treatments which very meticulous instrumentation is needed, these muscle discordances may lead to unexpected accidents such as tissue damage while filing, over-instrumentation and swallowing instruments. Also, taking radiographs for measuring canal length is often hindered by walking and movement disorders. This paper is to present a clinical case of one-visit root canal treatment using electrical apex locator under general anesthesia in a cerebral palsy patient.

• Steel and Composite Structures
• /
• 제3권6호
• /
• pp.451-474
• /
• 2003

Details are given of a cold-formed steel portal framing system that uses simple bolted moment-connections for both the eaves and apex joints. However, such joints function as semi-rigid and, as a result, the design of the proposed system will be dominated by serviceability requirements. While serviceability is a mandatory design requirement, actual deflection limits for portal frames are not prescribed in many of the national standards. In this paper, a review of the design constraints that have an effect on deflection limits is discussed, and rational values appropriate for use with cold-formed steel portal frames are recommended. Adopting these deflection limits, it is shown through a design example how a cold-formed steel portal frame having semi-rigid eaves and apex joints can be a feasible alternative to rigid-jointed frames in appropriate circumstances.

• 대한치과의사협회지
• /
• 제10권3호
• /
• pp.149-153
• /
• 1972

The apical foramen is not always found on the very tip of the root. The apical foramen may make its exit on the mesial, distal, labial or lingual side of a root slightly short of the root apex rather than at the root apex itself. The author collected 43 upper first molars and 84 lower first molars as a samples. Apical foramens were carefully checked and examined these location on each tip. (table 1) 1. About 33% to 49% of upper cases were found on extreme tip of roots and the remaining cases were on the distal side or mesial side. 2. Except distal simple canal of lower molars, approximately 40% to 50% were located on the very tip of the root. The remaining cases were on distal or mesial surface. 3. On lower distal simple canal, about 51% of cases made its exit on distal side. The remaining cases located on the tip end or mesial side.