• 대한교통학회:학술대회논문집
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• 대한교통학회 2007년도 제57회 학술발표회논문집
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• pp.870-877
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• 2007

• 콘크리트학회지
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• 제7권1호
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• pp.32-36
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• 1995

• 대한치과보철학회지
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• 제31권2호
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• pp.249-270
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• 1993

For understanding of anatomy, physiology, and diseases of human TMJ, it is required to evaluate quantitatively the movement of the disc and condyle head of mandible. The histologic section of cadaver TMJ were examined, and the magnification of the MR image and its details of anatomy were evaluated. And then a quantitative analytic method, by comparing the Sectograph and the MR image of vital human TMJ, was proposed. For this study, 15 subjects(Male, 24~35years) were selected from a prosthodontic examination randomly, and each subject’s five interocclusal rubber registration records were made on the ICP, and 5, 10, 15, and 20mmjaw opening positions. All subjects were radiographed with a Denar Quint Sectograph Image System(Denar Corp., USA), and imaged with a MRP-20EX MR Image System(0.2T, Permanent Magnet Type, Hitachi Medical Corp., Japan) using an 100mm diameter bilateral type surface coil. These images were traced on the acetate tracing paper, and analyzed In this study, the findings led to the following conclusions. 1. In comparison of the histologic section of autopsy specimen with the MR image at the same section, the size(dimension) of MR image was 70% of the real one. It was possible to recognize the shape of articular disc, anterior and posterior attachments, and adjacent soft tissues, because of the excellent reproducibility of anatomical structure. 2. When we compared the amount of joint space on MR image with that of joint space on sectograph, the amount of joint space on sectograph was significantly greater than that of joint space on MR image, except at the top of condylar head. 3. The position of minimum joint space on sectograph at intercuspal position didn't coincide with the middle position of articular disc on MR image, and was approximately in the anterior third of posterior band of articular disc. 4. The amount of condylar movement on MR image at opening movement was greater than that of articular disc movement. From Intercuspal position to 5mm jaw-opening movement, the condylar movement showed hinge one, and over the range 5mm jaw-opening it suggested hinge & translatory one. 5. In terms of area variation of articular disc measured on MR image in sagittal plane, the area of posterior band increased with increasing the amount of Jaw opening, but the area of anterior band decreased conversely.

• Imaging Science in Dentistry
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• 제32권2호
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• pp.113-118
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• 2002

Ankylosis of joint is defined as limited movement due to infection, trauma, or surgical procedure. A 59-year-old female with a chief complaint of limited movements during mouth opening had a positive history of trauma to her right TMJ area about 5 years ago. From that time, progressive mouth opening limitation and intermittent pain have occurred. At the time of admission the patient showed mandibular deviation to the right side during mouth opening, with a maximum opening limited to 5 mm. On plain radiographs, right condylar enlargement and joint space reduction by newly formed bony tissues were observed. CT scans showed right condylar enlargement, cortical sclerosis, and thickening of the condyle, articular fossa and articular eminence.

• 한국전산유체공학회지
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• 제19권1호
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• pp.21-26
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• 2014

Butterfly valve is a valve that controls fluid flow depending on the size of the opening angle. In general, the size of the opening angle of the valve increases, the fluid flow has also increased sharply. However, sometimes, in a specific piping system, a particular operating condition is needed that the fluctuation of the fluid flow should not have large amount although the size of opening angle of the valve become larger. In butterfly value, the shape of a typical thin plate, it is impossible to control a minute fluid, but in thick plate type, it is possible. In this study, we got the fluid flow control characteristics and pressure drop through both a numerical method and an experimental method about thick plate type. The numerical result and experimental result of flow coefficient show a similar pattern. In addition, we could find that minute fluid flow control was possible in the area of small size of the opening angle.

• 한국유체기계학회 논문집
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• 제15권6호
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• pp.5-10
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• 2012

The effect of pressure-side opening length on three-dimensional flow fields and aerodynamic losses downstream of a cavity squealer tip has been investigated in a turbine rotor cascade for the squealer rim height-to-chord ratio and tip gap height-tochord ratio of $h_{st}/c$ = 5.05% and h/c = 2.0% respectively. The opening length-to-camber ratio is changed to be $OL/c_c$ = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.7 The results show that longer OL leads not only to weaker secondary flow but also to lower aerodynamic loss in the tip leakage vortex region, while it significantly widens the area with high aerodynamic loss in the passage vortex region. The aerodynamic loss coefficient mass-averaged all over the measurement plane is kept almost constant for $0.0{\leq}OL/c_c{\leq}0.3$, whereas it increases rapidly for $OL/c_c$ > 0.3 in proportion to $OL/c_c$. There is little deterioration in flow turning with increasing $OL/c_c$.

• 대한기계학회논문집B
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• 제29권12호
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• pp.1299-1306
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• 2005

The suitable pressure regulator modeling at each opening ratio and pressure ratio is very important to obtain reliable results, especially in small scale pipeline network analysis such as a pressure regulator system. And it is needed to confirm both whether temperature recovery is achieved after passing by the pressure regulator's narrow neck and how much amount of low temperature area that can cause condensate accumulation is distributed by various PCV models and driving conditions. In this research, the numerical model resembling P company pressure regulator that is used widely for high pressure range in commercial, is adopted as the base model of CFD analysis to investigate pressure regulator's flow characteristics at each pressure ratio and opening ratio. And it is also introduced to examine pressure regulator's critical flow characteristics and possibility of condensation or freezing at each pressure ratio and opening ratio. Additionally, the comparison between the results of CFD analysis and the results of analytic solution obtained by compressible fluid-dynamics theory is attempted to validate the results of CFD modeling in this study and to estimate the accuracy of theoretical approach at each pressure ratio and opening ratio too.

• 한국환경생태학회지
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• 제29권1호
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• pp.21-28
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• 2015

This study examined the habitat status of wild birds at closed-trails and the control group of opened-trails in the national park of the Baekdudaegan mountains. After evaluating each area based on this, it's aimed at being utilized as basic data for future national park management and opening of trails. Upon field investigations and analyzing existing literary materials, it was found that there were a total of 76 bird species living around the trails. Among them, it was confirmed that 60 species can breeding and 10 species are protected by law. Upon assessing the scores of each area according to the evaluation standards of this study, Area I had 7 scores, area II had 13 scores, area III had 5 scores, and area IV had 16 scores, showing that the control group open-trail area IV between Jeongryeongchi and Seongsamjae had the highest score, and that area III of Wolyeongdae~Chotdaebong~Daeyasan~Miljae~Wolyeongdae had the lowest score. Evaluation of closed-trail according to wild bird species (Avifauna) was attempted in this study, but there were more bird species living in open-trails, while also having higher evaluation scores. Therefore, if opening trail is needed in the future due to excessive desires of visitors or inevitable social demands, it is judged that various environmental factors including mammals highly affected by people should be evaluated to open up the sector with the lowest score. Also, it is judged that through methods such as reservation systems, the number of visitors should be controlled or night-time hikes should be prohibited so that nocturnal wildlife can freely use the trails.

• International Journal of Fluid Machinery and Systems
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• 제5권3호
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• pp.109-116
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• 2012

Water hammer pumps can effectively use the water hammer phenomenon for water pumping. They are capable of providing an effective fluid transport method in regions without a well-developed social infrastructure. The results of experiments examining the effect of the geometric form of water hammer pumps by considering their major dimensions have been reported. However, these conventional studies have not fully evaluated pump performance in terms of pump head and flow rate, common measures of pump performance. The authors have focused on the effects on the pump performance of various geometric form factors in water hammer pumps. The previous study examined how the hydrodynamic characteristics was affected by the inner diameter ratio of the drive and lift pipes and the angle of the drive pipe, basic form factors of water hammer pumps. The previous papers also showed that the behavior of water hammer pump operation could be divided into four characteristic phases. The behavior of temporal changes in valve chamber and air chamber pressures according to the air volume in the air chamber located downstream of the lift valve was also clarified in connection with changes in water hammer pump performance. In addition, the effects on water hammer pump performance of the length of the spring attached to the drain valve and the drain pipe angle, form factors around the drain valve, were examined experimentally. This study focuses on the form of the lift valve, a major component of water hammer pumps, and examines the effects of the size of the lift valve opening area on water hammer pump performance. It also clarifies the behavior of flow in the valve chamber during water hammer pump operation.

• 한국도로학회논문집
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• 제10권3호
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• pp.139-147
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• 2008

1996년 천호대로 중앙버스전용차로가 시행된 이후 2008년 까지 8개 구간이 운영되고 있다. 그러나 중앙버스전용차로의 시행에 따른 직 간접적 영향권 내의 도로교통량 변화는 보고되지 않고 있다. 따라서 본 연구에서는 2004년 7월에 동시 개통된 3개 구간에 대한 사전 사후 도로교통량 변화를 분석하였다. 분석결과, 중앙버스전용차로 구간의 교통량은 중앙버스전용차로 개통 후(2004년 11월) 24.7%로 급격히 감소한 후, 개통 후 1년(2005년 11월) 1.4%로 안정화 된 것으로 분석되었다. 인접 우회도로 교통량은 개통 후(2004년 11월) 2.9% 감소한 후, 개통 후 1년(2005년 11월) 0.3%로 미비하게 증가하였다. 측정오차(${\pm}5%$)를 고려하면 중앙버스전용차로 교통수요는 안정화 단계에 들어섰으며, 자동차 수요가 인접지역으로 우회하기 보다는 타 수단으로 전환된 것으로 판단된다.