• 월간 기계설비
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• 통권44호
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• pp.86-89
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• 1994

• 대한기계학회논문집B
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• 제41권9호
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• pp.615-622
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• 2017

충격파관에서 발생하는 충격파는 저압관단으로 전파하며, 관단에서 반사한다. 반사 충격파와 경계층의 간섭으로 반사 충격파에 분지가 발생하게 되고, 분지한 반사 충격파는 접촉면과 간섭하며, shock train이 발생하게 된다. 그러나 충격파관에서 발생하는 shock train 현상에 대한 연구는 미흡한 실정이다. 본 연구에서는 2차원 축대칭 충격파관을 사용하여 비정상, 압축성 Navier-Stokes 방정식을 적용한 수치해석을 수행하였으며, shock train의 상세한 특성을 조사하기 위하여, 고정된 압력비에서 충격파관의 길이 및 직경을 변화시켰다.

• 대한기계학회논문집B
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• 제22권5호
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• pp.618-626
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• 1998

This paper describes a series of fundamental studies on reflection and emission of weak pressure waves from an open end of a pipe. Acoustical theories which have been employed in the plane pressure waves inside a pipe are applied to the present study. The objective of the present study is to investigate the reflection or emission coefficient of pressure wave at an open end of a pipe, the length of open end correction, and the directivity characteristics of the pressure waves emitted from the pipe. The results show that the reflection coefficient of pressure wave at an open end and the length of open end correction decrease for the wave length of pressure wave to increase. It is also found that the reflection coefficient for a baffle plate at the exit of pipe is larger than that for no baffle plate.

• 산업경영시스템학회지
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• 제33권3호
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• pp.71-78
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• 2010

The end shape of tube for automobile power steering system has influence on the ability of performance. In this case study, we attempted to optimize the forming process of a small tube using Taguchi experimental design methodology. A preliminary experiment was conducted and four main control factors were selected. The experiment was set up as an $L_9(3^4)$ orthogonal array, and determined the optimal levels of the four factors through the analysis of the experimental results. As a result, the performance characteristic(close adhesion power) of the product was improved about 36%. In addition, the process capability index $C_{pk}$ is enhanced from 0.94 to 6.85.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.544-549
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• 2003

When a shock wave arrives at an open end of tube, an impulse wave is discharged from the tube exit and causes serious noise and vibration problems. In the current study, the effect of the cross-sectional area of tube on the impulse wave is numerically investigated using a CFD method. The Harten-Yee's total variation diminishing(TVD) scheme is used to solve the axisymmetric, two-dimensional, unsteady, compressible Euler equations. With three different cross-sectional areas of tube, the Mach number of the incident shock wave $M_{s}$ is varied between 1.01 and 1.5. The results obtained show that the directivity and magnitude of impulse wave strongly depend upon the Mach number of incident shock wave and are influenced by the tube area. It is also known that the tube cross-sectional area significantly affects the magnitude of impulse wave at or near the tube axis.

• 물과 미래
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• 제22권4호
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• pp.435-440
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• 1989

단면이 급축소되는 관에서 액체의 급속한 채움에 의한 수격현상을 연속, 운동량, 그리고 에너지 방정식들을 이용하여 해석적으로 표시하였다. 이러한 관에 기존 수학모형인 MOC와 RCT를 적용한 결과에 의하면, 이러한 관단면의 급변화에 의하여 수격작용이 예상되는 경우의 부정류해석에는 Rigid Column Method의 사용은 제한되어야 하며 Method of Characteristic를 사용하여야 한다.

• 건축역사연구
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• 제16권2호
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• pp.99-118
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• 2007

Kyedan(戒壇) is an altar to perform a rite of Buddhist Initiation which gives Precept to a Buddhist monk. Sometimes it is called the Place of Precept and Mandala by Sanskrit. In this study, the Sutra of the Tang(唐) Dosun(道宣) regarding First Kyedan of Jetavana-anathapindasyarama(祇園精舍), which was the first temple such as, Kyedandokyung(戒壇圖經), Kiwonsadokyung(祇洹寺圖經), Sabunyul(四分律) were analyzed to find out original form and layout. Ultimately, the study was intended to examine the spatial formation-principle by comparing with Kyedan Temple. The results of this study could be summarized as below. First. Except for Kyedan in Bakryensa, the height of lower stone plate of Buddhist Bell-Shaped Stupa of Korean Kyedan is higher than three storied Kyedan that described in Kyedandokyung. Second. Buddhist Bell-Shaped Stupa above Kyedan was presumed that embodied image of Bell Pedestal and symbolism of overturned-bowl were combined together, when Kyedandokyung and Kiwonsadokyung were referred. It could be examined by the existence of stone lantern. Third. In Korea, the rite of Buddhist initiation that gives Precept in Kyedan has been considered impossible. However, when the rite was conducted, there was a possibility to establish wood stair. It is because that the Buddhist Stupa of Silleuuksa(神勒寺) and Woljeongsa(月精寺), which reflected the image of Kyedan had stone stair. Fourth, The method to build Kyedan of Dosun divided into Large Region and Small Region was applied to the method to construct Stone terrace behind Jeongmyeolbogung(寂滅寶宮) like Tongdosa(通度寺) and complete Kyedan on the stone terrace. In other words, Jeongmyeolbogung became Kyedanwon(戒壇院) and Kyedan, itself became Small Region. The area of Stone terrace became Large Region and naturally, they constituted an Institution. Fifth, Korean Kyedan which is consist of Jeongmyeonlbogung and Kyedan is a Korean original composition principles of Kyedangaram(戒壇伽藍) that can satiate all the functions of Kyedan as a religious subject and the place of the rite of Buddhist initiation, as it had complex of Outdoor Kyedan, which was suggested by the sutra of Dosun and Institution of Kyedan.