• 한국방사선학회논문지
• /
• 제13권5호
• /
• pp.675-681
• /
• 2019

근골격계 수술 전 CT 촬영 후 3차원 체적영상을 Increment별로 구현하는 과정에서 시간이 많이 소요되지 않고 데이터의 양도 많지 않은 적절한 Increment를 찾아 제안하고자 한다. 이에 본 연구에서는 손, 무릎, 발인체팬텀을 CT로 검사후, MMWP 프로그램을 사용하여 3차원 체적영상을 구현하여 재현성 평가를 하였다. 첫 실험으로는 각 Increment에 따른 세 가지 인체팬텀 별 데이터양을 분석하였다. 두번째 실험으로는 재현성평가와 실측 길이를 비교하였다. Increment에 따라 각 팬텀별로 이미지 데이터양을 분석한 결과 Increment를 0.1mm 로 설정했을 때보다 1.0mm 로 설정하였을 때 1/10 정도로 데이터양이 줄어드는 것을 확인할 수 있었다. 구현성 평가를 하였을 때 손 팬텀은 0.7mm, 무릎 팬텀과 발 팬텀은 0.6mm 부터 gap이 생성되었고 실제 팬텀과 실측 길이를 비교하였을 때 길이가 많이 차이나서 구현성이 낮아지는 것을 확인할 수 있었다. Increment가 1.0mm 에 가까울수록 이미지 수가 적고, 3D 구현 시간이 적게 소요되지만 gap이 생성되면 구현성이 급격이 낮아지는 것을 확인할 수 있었다. 따라서 영상의 gap이 생성되기 전 Increment를 알아내어 적용하는 것이 수술 전 진단을 내리기에 가장 적합하다. 본 연구를 통해 CT 촬영후 VRT Rendering을 통한 3D 영상 구현시 정확한 Increment 설정을 증명할 수 있는 지표가 되기를 기대한다.

• Nuclear Engineering and Technology
• /
• 제27권3호
• /
• pp.344-357
• /
• 1995

핵연료 소결체와 피복관 사이의 간극 크기에 크게 좌우되는 간극 열전도도는 연료봉내 초기 저장에너지 양에 중요한 영향을 끼친다. 정상상태 계산용 ELESTRES 코드에서 사용 중인 수정된 Ross-Stoute 의 간극 열전도도 모델은 단순한 열적 변형 모델에 기초한다. 최근의 실험에서 핵연료 소결체가 연소됨에 따라서 균열, 소결체 재배열 등이 발생되고, 피복관 내부의 편심에 위치하게 된다는 것이 알려졌다. 본 논문에서는, 최근에 제안된 편심형 간극 모델과 소결체 재배열형 간극 모델 등이 기술되었고, 실험 조건과 중수로 핵연료봉의 운전조건 하에서의 소결체와 피복관 사이의 간극 열전도도를 계산하는데 이용되었다. 실험 치와 계산치가 잘 일치됨으로써, 수정된 Ross-Stoute 모델이 ELESTRES 코드 내에서 사용된 열전달 관련 가정들과 잘 부합됨을 보여 주었다. 출력 경계곡선을 따라서 수정된 Ross-Stoute 모델로 계산된 간극내 열전달과 핵연료 표면 온도 등이 편심형 간극 모델과 소결체 재배열형 간극모델에 의한 예측치보다 보수적이었다.

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2004년도 추계학술발표대회 개요집
• /
• pp.76-78
• /
• 2004

The phenomenon of weld shrinkage mainly occurs owing to residual stress by heating, which largely effects on welding quality, Actually as the shrinkage rate depends on the weld deposit amount, so it is desired that the sectional area of weld joint shall be reduced. In this respect the Electron beam welding has more profitable position compare to Narrow-gap TIG welding which is even superior to other arc welding processes. In case of thick austenitic stainless steel the shrinkage rate of Electron beam welding has about $10\%$ of Narrow-gap TIG welding's, which means that residual stress is a lot less than that of Narrow-gap TIG welding. And heat input and welded section area also indicate large difference between two processes.

• Journal of Veterinary Science
• /
• 제25권2호
• /
• pp.26.1-26.6
• /
• 2024

Bone loss from the kerf of the sawblade may influence the final outcomes when employing three-dimensional-printed surgical guides. However, no studies have systematically addressed saw blade-induced bone loss. This study aims to quantify bone loss and propose a reduction guide to minimize the fracture gap. The postoperative gap tended to decrease as the amount of gap compensation increased. Osteotomy gaps can be attributed to the thickness of the saw blade, and the proposed methodology addresses this surgical error. Surgeons can proactively plan and design reduction guides with applied compensation using the method described in this study.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2003년도 춘계학술대회논문집
• /
• pp.164-167
• /
• 2003

Profile ring rolling process is simulated by using the general purpose commercial finite element analysis software MSC.Superform Because the deforming region is restricted to the vicinity of the roll gap, only a ring segment spanning the roll gap is analysed in order to save computation time and cost. A profile ring with an external round groove is chosen as an example to be analysed. The rolls with and without groove were analysed to compare the amount of side spread. It is found that the grooves in the rolls reduce the amount of side spread.

• 소성∙가공
• /
• 제12권7호
• /
• pp.631-639
• /
• 2003

Ring rolling process is simulated by using the general-purpose commercial finite element analysis software, MSC.Superform. Because the deforming region is restricted to the vicinity of the roll gap, only a ring segment spanning the roll gap is analyzed in order to save computation time and cost. First, a plain ring rolling of rectangular cross-section is simulated. Comparisons between computation and experiment show good agreement in the cross-sectional configuration of the deformed ring. Then, a profile ring with an external round groove is analyzed. The rolls with and without groove have been analyzed to compare the amount of side spread. It is found that the grooves in the rolls are effective in reducing the amount of side spread.

• 한국의류학회지
• /
• 제29권11호
• /
• pp.1399-1409
• /
• 2005

The purpose of this study was to analyze the shape of gathered skirts using a three-dimensional measurement system. And in this experiment, I try to accumulate three-dimensional data of wearing model and to figure out analyzing method made by shape of clothes. The experimental design consists of two factorial designs. I set up three different kinds of fabrics, ratio of gathers. Therefore nine samples were made. The instrument and tools for three-dimensional measurement was whole body 3D scanner. Analysis program used in experiment is RapidForm 2004 PP1 and Pattern Design 2000. Data analysis utilizes SPSS WIN 10.0 Package. T-test to effect an inspection of evidence, there was difference about measurement times. One-way ANOVA to analysis effect of gather made by gathering conditions. The following results were obtained; 1. As a result of inspecting an error several times using a three-dimension measurement system, convinced data was obtained. 2. At front, distribution of gap amount was larger than back. And as ratio of gathers increased, distribution of gap amount showed regularly. 3. After analyzing horizontal sectional figure of skirts, as a height of skirt changed from waist to the bottom of skirts, the results showed as follows. While section width, section thickness, node width, node depth increased, node count decreased. 4. With the horizontal section levels of gather skirt, the silhouette on middle hip section was similar with the silhouette of body line. And as ratio of gathers around hip section increased, nodes showed regularly. At the bottom of skirts showed different nodes by different gathering condition.

• 한국구조물진단유지관리공학회 논문집
• /
• 제25권6호
• /
• pp.199-208
• /
• 2021

3D 프린팅 콘크리트의 출력성능 및 부재 강도는 물시멘트비(Water cement ratio, W/C)와 레이어의 프린팅 시간 간격(Printing Time Gap, PTG)에 의하여 큰 영향을 받을 수 있다. 이 연구에서는 W/C와 PTG를 변수로 하여 제작된 프린팅실험체와 몰드 실험체의 표면수분량과 전단부착강도와의 관계를 측정·고찰하였으며, 그 결과, 레이어표면수분량이 전단부착강도에 큰 영향을 주는 것으로 나타났다. 따라서, 3D 프린팅 출력 시 요구되는 레이어 계면 전단부착성능을 확보하기 위해서는 PTG에 따라 적절한 레이어표면수분량이 유지될 수 있도록 유의해야 하며, 레이어표면수분량에 영향을 줄 수 있는 여러 가지 프린팅 환경인자들 대한 후속 연구도 필요할 것으로 판단된다.

• Restorative Dentistry and Endodontics
• /
• 제20권2호
• /
• pp.432-461
• /
• 1995

The basic principles in the design of Class II amalgam cavity preparations have been modified but not changed in essence over the last 90 years. The early essential principle was "extension for prevention". Most of the modifications have served to reduce the extent of preparation and, thus, increase the conservation of sound tooth structure. A more recent concept relating to conservative Class II cavity preparations involves elimination of occlusal preparation if no carious lesion exists in this area. To evaluate the ideal ClassII cavity preparation design, if carious lesion exists only in the interproximal area, three cavity design conditions were studied: Rodda's conventional cavity, simple proximal box cavity and proximal box cavity with retention grooves. In this study, MO amalgam cavity was prepared on maxillary first premolar. Three dimensional finite element models were made by serial photographic method. Linear, eight and six-nodal, isoparametric brick elements were used for the three dimensional finite element model. The periodontal ligament and alveolar bone surrounding the tooth were excluded in these models. Three types model(B option, Gap option and R option model) were developed. B option model was assumed perfect bonding between the restoration and cavty wall. Gap option model(Gap distance: $2{\mu}m$) was assumed the possibility of play at the interface simulated the lack of real bonding between the amalgam and cavity wall (enamel and dentin). R option model was assumed non-connection between the restoration and cavty wall. A load of 500N was applied vertically at the first node from the lingual slope of the buccal cusp tip. This study analysed the displacement, 1 and 2 direction normal stress and strain with FEM software ABAQUS Version 5.2 and hardware IRIS 4D/310 VGX Work-station. The results were as followed. 1. Rodda's cavity form model showed greater amount of displacement with other two models. 2. The stress and strain were increased on the distal marginal ridge and buccopulpal line angle in Rodda's cavity form model. 3. The stress and strain were increased on the central groove and a part of distal marginal ridge in simple proximal box model and proximal box model with retention grooves. 4. With Gap option, Rodda's cavity form model showed the greatest amount of the stress on distal marginal ridge followed by proximal box model with retention grooves and simple proximal box model in descending order. 5. With Gap option, simple proximal box model showed greater amount of stress on the central groove with proximal box model with retention grooves. 6. Retention grooves in the proximal box played the role of supporting the restorations opposing to loads.

• 한국전기전자재료학회논문지
• /
• 제37권3호
• /
• pp.292-296
• /
• 2024

In this study, Iron (III) oxide-hydroxide (δ-FeOOH) was successfully synthesized using hydrogen peroxide (H₂O₂) as an oxidizing agent. The synthesis of δ-FeOOH was carried out by controlling the amount of H₂O₂, and pure δ-FeOOH was successfully synthesized in ranges from 0.2 mL to 0.6 mL of H₂O₂. The size of the synthesized δ-FeOOH particles was compared by controlling the amount of oxidant H₂O₂. The average particle size of the synthesized pure δ-FeOOH particles increased from 875.1 nm to 897.2 nm as the amount of H₂O₂ was increased. The optical properties of δ-FeOOH synthesized under these specific conditions were investigated. All δ-FeOOH showed a similar trend of increasing and decreasing light absorption from 800 nm to 400 nm, although there was a slight difference in the amount of light absorption, with the largest amount of light absorption at 410 nm. The band gap energy of δ-FeOOH through the Tauc plot method was about 2.1~2.2 eV when H₂O₂ was 0.2~1.4mL. With a sufficient small particle size, simple control of that particle size, and a small band gap energy enough to absorb light in the visible spectrum, δ-FeOOH could be useful in a variety of applications, including photoelectrochemistry and battery electrodes.