• 한국항공우주학회지
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• 제36권8호
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• pp.790-796
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• 2008

고체 추진기관은 고정된 추진제 그레인 형상과 노즐목 때문에 정해진 단순 추력을 가지게 된다. 핀틀 노즐은 기존의 고체 추진기관의 장점을 가지면서도 추력 조절이 불가능한 단점을 보완하기 위해 제안된 방법이다. 본 연구에서는 핀틀 형상이 노즐 성능에 미치는 영향을 실험과 수치해석 방법으로 평가하였다. 핀틀 형상은 단순성의 원리에 근거하여 변경하였으며 각각의 형상에 대한 내부 유동장은 난류모델을 적용하여 Fluent로 해석하였다. 본 연구로부터 핀틀 형상이 노즐내의 충격파 구조 및 유동박리 영향을 주어 노즐 추력 및 핀틀 하중에 영향을 미침과 최적의 노즐 성능을 발휘할 수 있는 핀틀 형상이 존재함을 확인하였다.

• 한국항공운항학회지
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• 제18권3호
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• pp.9-20
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• 2010

Surveillance is an enabler of safety with respect to aircraft separation and as a consequence capacity and efficiency with respect to aircraft operations. The new emerging technology among modern civil aviation surveillance is Multilateration (MLAT) which would affect on the surveillance capacity with both side of surveillance signal and operational properties. Multilateration system is needed to receive the signal which must reach at least 3 ground receivers simultaneously and has the effect that will have on with the ultimate accuracy. In this paper, the principle and the system configuration are reviewed. And its benefit of development is considered with use in situations where it is difficult to locate tranditional radar. This MLAT requires no additional avionics equipment to supply service with more accurate and less expensive. And it is able to enhance performance that meets international standards and extend the investment of air navigation service providers with reducing environmental impact by utilizing a small footprint on existing structures. Finally, it can be added to meet a wide range of coverage requirements and future surveillance needs.

• 건축역사연구
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• 제11권1호
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• pp.65-84
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• 2002

This study has main purpose to understand and interpret the house Nok-U-dang, an upper class built in Chosun dynasty, not by outsider researcher's view but insider dweller's view. To interpret correctly, dweller's everyday life in the space and form is examined on a microscale beyond the physical space and form of the house, main object of architectural history To understand the present form exactly, the study restore traditional life in past era, 1940s. Main method of restoration is the ethnographic interview, based on cultural anthropology. Like any other upper-class house, the house has been influenced under ruling Confucian ideology in Chosun dynasty: separation of man's and woman's quarters and hierachical arrangement by generation, and worshipping ceremony for ancestor. However, it is by practical management for agricultural production that every court and building of the Noku-Dang can be explained correctly; preparing seed for sowing, tool storing, preparing and serving meal for laborers, making manure, harvesting, threshing grain, storing grain and so on. Precedent studies interpreted the house by the Confucian principle too much and made conclusion of dignity and austerity of ritual: woman's quarter, is closed and serene space. However this study shows that the space is semi-opened and composite space by agricultural works. And the Sarangchae, master's quarter, is located properly at visual center to control every agricultural activity.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권5호
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• pp.362-368
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• 2004

A new one-column chromatography process, analogous to a four-zone simulated moving bed (SMB), was presented. The basic principle of the process was identical to that of a four-zone SMB. The process consisted of one chromatographic column and four tanks, instead of the four columns in the four-zone SMB (1-1-1-1), and has been used for the separation of two amino acids, phenylalanine and tryptophan, using an ion exchange resin. The operating parameters for the one-column process and four-zone SMB were obtained from equilibrium theory. Computer simulations were used to compare the performances of the new one column process to that of the general four-zone SMB, using Aspen $Chromatography^{TM}$ v 11.1. The differences between the one-column and SMB processes in terms of the purities and yields of phenylalanine and tryptophan were less than 4 and about $6\%$, respectively. The lower purities of the one-column process were due to the loss of the developed concentration profiles in the column when the liquid was stored in tanks. The one-column process gave great flexibility, and would be useful for reconstructing an existing conventional chromatography process to one of a SMB.

• 공업화학
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• 제24권3호
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• pp.239-246
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• 2013

기존의 발포유리 제조공정의 원리는 원료유리분말을 거푸집에 담아 발포소성시키며, 발포소성 후에 발포체를 거푸집과 분리 후에 서냉 열처리를 하는 것이다. 이러한 이유로 기존의 발포유리 제조공정은 연속생산이 불가능하다. 본 연구에서는, 발포유리의 연속생산공정을 개발하기 위해서 거푸집을 사용하지 않는 대신, 원료유리분말을 가압성형하여 먼저 성형체를 만들고, 이 성형체를 발포시켜 발포유리를 생산하는 새로운 발포유리제조공정의 가능성을 타진하였다. 수화된 소다석회 유리분말을 사용하고 유리의 발포에 가장 핵심적인 발포제를 달리한 가압성형체를 발포소성시키는 실험 결과를 통해서, 거푸집을 사용하지 않고서도 발포유리의 연속생산공정이 가능할 수 있음을 확인하였다.

• 한국유기농업학회지
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• 제21권1호
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• pp.1-18
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• 2013

Animal and crop production systems were integrated on a single farm. This integrated farming system recycled nutrients on the farm. The separation of animal and crop production with the introduction of cheap commercial fertilizers, farms were not used land-applied manure. The on-line manure matching is one of the emerging business in the achievement of recycling and resource recovery. The manure matching actively promotes the reuse and recycling of by-products and manure. This study constructs to manure matching information system to solve the exchange problems between herders and croppers. Manure matching web sites designed. This paper introduces a web-based animal manure matching system. A manure matching service, part of the manure transport, links farmers who produce excess manure with farmers who can use the manure. Farmers registered with the service have requested manure. The manure matching service supports the transport project by linking farmers with excess manure with those farmers who can utilize the manure safely as a nutrient source. The goal of the service is to protect water quality by fostering efficient land application. Benefits to those who use the manure network include reduced disposal costs, lower purchase costs and recycling of manure. The manure matching is based on the principle that 'one persons waste is another person's fertilizer.' It provides a free online matchmaking service for environmentally safe manure recycling management system.

• 한국수소및신에너지학회논문집
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• 제15권3호
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• pp.220-227
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• 2004

The purpose of this paper is, based on the theoretical background of the principle of gas purification and absorption, and the absorbing ability of metals, to syudy the efficiency of gas purification of inorganic gases using Zr alloys, so as to contribute to the IT industry. To produce and distribute gas with high purity and ultra-high purity, different types of gas purifier are currently being used: distillation type, getter type, catalyst type, absorption at low-temperature type, and membrane separation equipment. From the different purification methods mentioned above, the getter type gas purifier is capable of not only high performance and capacity but also P.O.U(Point Of Use) method. The key of the getter type gas purifier is its efficiency of gas purification, which is the subject chosen for this study.

• 복식
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• 제54권5호
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• pp.125-138
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• 2004

This study has the aim of defining the special characteristics and images of the rainbow colored fashion by understanding the theoretical bases of rainbow colors and analyzing rainbow colored fashion images in historical materials. western and folk costumes. modern fashion design. Giving careful consideration to the rainbow colored fashion makes it possible to develope the innovative way of fashion design to satisfy the needs of color usual for designers and colorists. To obtain the purposes, document study and survey study have been executed. The results of this study are as follows. In document studies, the beginning of rainbow colored fashion went back in ancient Egypt. Also saikdong of korea, poncho of indians are the examples of the rainbow colored fashion. The rainbow colored fashion were put on a man of position in principle ceremony for ornaments. In survey studies, the clothing perception characteristics in rainbow colored fashion were analyzed. Main factors of perception characteristics In the rainbow colored fashion are ＇closed form＇, ＇whole＇, ＇indeterminate＇, ＇rounded＇, ＇planar separation＇ The factors that affect the perception of rainbow colored fashion are ＇closed form＇ and ＇indeterminate＇ characteristics. And rainbow colored fashion images and clothing perception characteristics can be classified into four main images : Vigorous, Colorful/fairy, Fresh, Mysterious/brilliant. Therefore. this study is to systematize the characteristics and images of rainbow colors. Based on the results makes it possible to adapt rainbow colors to fashion design efficiently, for the suggested design elements and color palettes include basic three fashion design elements color. texture. form.

• Bulletin of the Korean Chemical Society
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• 제14권4호
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• pp.515-519
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• 1993

The retention behavior of proteins was investigated by using hydrophobic interaction chromatography (HIC), comparing to the results obtained in reversed-phase chromatography (RPC) described in the previous paper. A SynChropak propyl column was employed with 0.05 M phosphate buffer (pH 7.0) containing sodium sulfate. Conformational changes were recognized by examining Z values as a function of sodium sulfate concentration over a range of temperature between 5 and 65$^{\circ}C$. Z values did not change significantly at the range of the temperature showing the consistent ${\Delta}H^{\circ}$ and ${\Delta}S^{\circ}$ values. The sign and the magnitude of ${\Delta}H^{\circ}$ and ${\Delta}S^{\circ}$ of proteins in HIC were compared with those obtained in RPC. The signs of ${\Delta}H^{\circ}$ and ${\Delta}S^{\circ}$ of proteins in HIC were all positive, while those of proteins in RPC were all negative. These results suggested that the retention of proteins in HIC and in RPC were entropy-driven and enthalpy-driven process, respectively. From the two different investigations, it was concluded that the retention mechanism of RPC and HIC was based on the same fundamental principle in which separation is dependent on hydrophobicity, but the retention behavior of the proteins in HIC is clearly different from that observed in RPC.

• 호남수학학술지
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• 제41권2호
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• pp.403-420
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• 2019

The Helmholtz equation represents acoustic or electromagnetic scattering phenomena. The Method of Lines are known to have many advantages in simulation of forward and inverse scattering problems due to the usage of angle rays and Bessel functions. However, the method does not account for the jump phenomena on obstacle boundary and the approximation includes many high order Bessel functions. The high order Bessel functions have extreme blow-up or die-out features in resonance region obstacle boundary. Therefore, in particular, when we consider shape reconstruction problems, the method is suffered from severe instabilities due to the logical confliction and the severe singularities of high order Bessel functions. In this paper, two approximation formulas for the Helmholtz equation are introduced. The formulas are new and powerful. The derivation is based on Method of Lines, Huygen's principle, boundary jump relations, Addition Formula, and the orthogonality of the trigonometric functions. The formulas reduce the approximation dimension significantly so that only lower order Bessel functions are required. They overcome the severe instability near the obstacle boundary and reduce the computational time significantly. The convergence is exponential. The formulas adopt the scattering jump phenomena on the boundary, and separate the boundary information from the measured scattered fields. Thus, the sensitivities of the scattered fields caused by the boundary changes can be analyzed easily. Several numerical experiments are performed. The results show the superiority of the proposed formulas in accuracy, efficiency, and stability.