International Insurance Seminar 12 참석보고(參席報告)

유호선 한국보험학회 1977 保險學會誌 Vol.13 No.-

성능선도에 의한 다통로 판형열교환기의 간이설계법

유호선,이근휘,방보청 대한설비공학회 1999 설비공학 논문집 Vol.11 No.2

Based on a set of performance plots relating the design variables to the imposed conditions, an easy-to-use and versatile design procedure for chevron-type multipass plate heat exchangers is developed. In order for the present procedure to cover multipass with unequal passes and non-unity ratio of heat capacity rate, each stream number of transfer unit is adopted as the basic design variable instead of the exchanger number of transfer unit. It is found that there exists a unique relation between the stream and exchanger number of transfer units regardless of the chevron angle and the plate length. In addition, for a given value of the pressure drop the heat transfer area per unit mass flow rate can be expressed in terms of the stream number of transfer unit only. These two relationships in the form of simple plots constitute the framework of design. The sample results in comparison with the available data indicate that the present procedure includes the previous ones as a subset, and that every design method is affected essentially by the selection of specific correlations for the heat transfer coefficient and the friction factor.

변온유입 성층축열조의 충전과정에 대한 해석적 접근

유호선,Yoo, Hoseon 대한설비공학회 1997 설비공학 논문집 Vol.9 No.1

This paper presents an approximate analytical solution to a two-region one-dimensional model for the charging process of stratified thermal storage tanks with variable inlet temperature in the presence of momentum-induced mixing. Based on the superposition principle, an arbitrary-varying inlet temperature is decomposed into inherent discontinuous steps and continuous intervals approximated as a finite number of piecewise linear functions. This approximation allows the temperature of the upper perfectly-mixed layer to be expressed in terms of constant, linear and exponential functions with respect to time. Applying the Laplace transform technique to the model equation for the lower thermocline layer subject to each of three representative interfacial conditions yields compact-form solutions, a linear combination of which constitutes the final temperature profile. A systematic method for deriving solutions to the plug-flow problem having polynomial-type boundary conditions is also established. The effect of adiabatic exit boundary on solution behaviors proves to be negligible under the actual working conditions, which justifies the assumption of semi-infinite domain introduced in the solution procedure. Finally, the approximate solution is validated by comparing it with an exact solution obtained for a specific variation of inlet temperature. Excellent agreements between them suffice to show the necessity and utility of this work.

추사 김정희의 불교시 연구

유호선 한국불교학회 2006 韓國佛敎學 Vol.46 No.-

This study argued about the Buddhistic poems of Kim, Jeong-hee, a Confucian scholar in late Joseon dynasty. In this period, there were various changes in politic, economic, cultural field and that result, there was the moderate eyes on the Buddhism, unlike the Western Learnings(西學), which had been considered heresy until then. Kim, Jeong-hee accepted the Buddhism which ranged over Hinayana, Mahayana and Zen-meditation. The famous Zen-controversy with Back-pa(白坡) showed his concerns and his own Buddhistic opinions however this study didn’t deal with it because it had rooms for any interpretation of argument. This study tried to work that supposed his Buddhistic ideas through analysis on his Buddhistic poetry. He thought that the confucianism is confucianism itself, Buddhism is Buddhism itself majesticly. In result, he criticized the diagramaic unification of confucianism and Buddhism. It is a matter of course that Zen is also Zen itself, Hwa-eom(華嚴) is Hwa-eom itself and Prajna(般若) is prajna itself. In brief, his Buddhistic mind we can read in his poetry is classified as follows. The first is the stop of judgment and the enthusiasm of ascetic exercises. The second is the superiority of division and the pursuit of the agreement. The third is the Hwa-eom world view that never have any obstacles. And we are compelled to refer the association with the monks who helped to conduct detonation to Buddhism. 추사 김정희가 활동한 19세기 전반의 조선은 청조 학문의 유입과 국내의 다기한 사상의 영향으로 정치, 사회, 문화 전반에 걸친 변화가 일었고, 사상계에서도 이단시되던 불학에 대해 서학(西學)과는 달리 온건한 시선을 보내게 되었다. 추사는 성리학 뿐 아니라 불교사상을 수용하여, 소승과 대승, 선의 영역에까지 학문 범위를 넓혔다. 추사에게 유교는 유교만의 장처(長處)를 지니며 불교는 불교만의 장처를 지니는 엄연한 독립체였고 따라서 유불 사상의 도식적인 회통을 비판하였다. 불교 안에서도 추사에게 있어 선(禪)은 선 자체이고, 화엄은 화엄이며, 반야는 반야로 존재하지 그것들은 섞이지 않았다. 이에 본고에서는 그의 시문과 게송을 통해 불교인식을 추체험해 보는 작업을 시도해 보았다. 추사의 시에서 읽게 되는 불교적 정신세계란, 요컨대 사고나 판단이 정지된 몰입의 경지 즉 선적(禪的) 깨달음에 대한 희구와 수행이 모습으로, 진속(眞俗), 동정(動靜), 청탁(淸濁)의 분별을 지양하고 초월하는 불이평등(不二平等)의 현실인식으로, 분별과 분별없음이 넘나들고 육진(六塵)과 선(禪)의 파격이 장애를 일으키지 않는 화엄법계의 세계관으로 대별할 수 있을 것이다. 또한 이러한 정신세계를 촉발하도록 조력한 승려들과의 교유를 언급하는 일도 빼놓을 수 없을 것이다.

완전혼합영역을 갖는 성층축열조의 충전과정에 대한 이론적인 해석

유호선,박이동,Yoo, H.,Pak, E.T. 대한설비공학회 1995 설비공학 논문집 Vol.7 No.2

A theoretical one-dimensional model for the charging process in stratified thermal storage tanks is established presuming that the fluid ensuing from the tank inlet creates a perfectly mixed, layer above the thermocline. Both the generic and asymptotic closed-form solutions are obtained via the Laplace transformation. The asymptotic solution describes the nature of the charging pertaining to the case of no thermal diffusion, whereas the generic solution is of practical importance to understand the role of operating parameters on the stratification. The present model is validated through comparison with available experimental data, where they agree well with each other within a reasonable limit. An interpretation of the exact solution entails two important features associated with the charging process. The first is that an in-crease in the mixing depth $h_m$ causes a relatively slow temperature rise in the perfectly mixed region, but on the other hand it results in a faster decay of the overall temperature gradient across the thermocline. Next is the predominance of the mixing depth in the presence of the prefectly mixed region. In such a case the effect of the Peclet number is marginal and there-fore the thermal characteristics are solely dependent on the mixing depth paticularly for large $h_m$. The Peclet number affects significantly only for the case without mixing. Variation of the storage efficiency in response to the change in the mass flow rate agrees favorably with the published experimental results, which confirms the utility of the present study.

체적수축유동이 있는 포정합금의 방향성주조에 대한 상사해

유호선,정재동,이준식 대한기계학회 2001 大韓機械學會論文集B Vol.25 No.4

This paper presents a similarity solution for the directional casting of binary peritectic alloys in the presence of shrinkage-induced flow. The present model retains essential ingredients of alloy solidification, such as temperature-solute coupling, macrosegregation, solid-liquid property differences, and finite back diffusion in the primary phase. An algorithm for simultaneously determining the peritectic and liquidus positions is newly developed, which proves to be more efficient and stable than the existing scheme. Sample calculations are performed for both hypo- and hyper-peritectic compositions. The results show that the present analysis is capable of properly resolving the solidification characteristics of peritectic alloys so that it can be used for validating numerical models as a test solution.

재래시장 활성화를 위한 u-Market 서비스 수용성에 영향을 미치는 요인 연구

유호선,김재경,김민용,권오병,조혜경 한국경영정보학회 2008 Information systems review Vol.10 No.2

유희적인 유비쿼터스 서비스 수용에 영향을 미치는 요인에 관한 연구

유호선,김민용,권오병 한국경영정보학회 2009 한국경영정보학회 학술대회논문집 Vol.2009 No.-

전기화학적 양극분극시험에 의한 고온 설비부재의 열화손상 평가

유호선,송문상,송기욱,류대영,Yu, Ho-Seon,Song, Mun-Sang,Song, Gi-Uk,Ryu, Dae-Yeong 대한기계학회 2000 大韓機械學會論文集A Vol.24 No.6

The structural steels of power plant show the decrease of mechanical properties due to degradation such as temper embrittlement, creep damage and softening during long-term operation at high temper ature. The typical causes of material degradation damage are the creation and coarsening of carbides(M23C6, M6C) and the segregation of impurities(P, Sb and Sn) to grain boundary. It is also well known that material degradation induces the cleavage fracture and increases the ductile-brittle transition temperature of steels. So, it is very important to evaluate degradation damage to secure the reliable and efficient service condition and to prevent brittle failure in service. However, it would not be appropriate to sample a large test piece from in-service components. Therefore, it is necessary to develop a couple of new approaches to the non-destructive estimation technique which may be applicable to assessing the material degradation of the components with not to influence their essential strength. The purpose of this study is to propose and establish a new electrochemical technique for non-destructive evaluation of material degradation damage for Cr-Mo steels which is widely used in the high temperature structural components. And the electrochemical anodic polarization test results are compared with those of semi-nondestructive SP test.

이원합금의 수지상응고에 대한 일반화된 Scheil식

유호선,Yu, Ho-Seon 대한기계학회 1996 大韓機械學會論文集B Vol.20 No.7

A generalized Scheil equation for the solute redistribution in the absence of the back diffusion during the dendritic solidification of binary alloys is derived, in which coarsening of the secondary dendrite arms is taken into account. The obtained equation essentially includes the original Scheil equation as a subset. Calculated results for typical cases show that the coarsening affects the microsegregation significantly. The eutectic fraction predicted for coarsening is considerably smaller than that for fixed arm spacing. The most important feature of the present equation in comparison with the Scheil equation lies in the fact that there exists a lower limit of the initial composition below which the eutectic is not formed. Based on the generalized Scheil equation and the lever rule, a new regime map of the eutectic formation on the initial composition-equilibrium partition coefficient plane is proposed. The map consists of three regimes: the eutectic not formed, conditionally formed and unconditionally formed, bounded by the solubility and diffusion controlled limit lines.