• 한국항공우주학회지
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• 제37권2호
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• pp.193-200
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• 2009

본 논문에서는 소형항공기용 유-공압 방식(oleo pneumatic type) 착륙장치의 낙하특성을 연구하였다. 본 연구대상의 착륙장치의 방식은 미터링 핀이 없는 단순 유-공압 방식댐퍼 이다. 일반적으로 유-공압 방식의 착륙장치는 단순한 구조로 되어 있어 무게가 가볍고 좋은 충격흡수 효율을 가진다. 낙하해석을 위하여 상용 코드인 MSC ADAMS를 이용하여 모델링 하였다. 모델링한 후에 해석과 시험결과의 상사성을 검증하기 위하여 일련의 시험이 수행되었다. 시험과 해석결과의 보다 좋은 일치성을 얻기 위하여 해석 모델에 공동현상 효과가 고려되었다. 공동현상을 고려한 착륙장치의 동적 거동 시뮬레이션 결과들이 현저하게 개선되었으며 시험결과와 보다 잘 일치함을 확인하였다. 이러한 과정을 통해 신뢰성이 검증된 해석모델을 이용하여 경사면에 대해서 해석적 방법을 통해 낙하특성을 예측하였다.

• 조명전기설비학회논문지
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• 제23권12호
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• pp.176-183
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• 2009

대형병원의 에너지 소비패턴을 분석한 후 마이크로가스터빈을 적용할 경우 기존 시스템 대비 냉난방에너지 절감량 및 전기에너지 절감량과 경제성분석을 통해 대형병원의 에너지 소비량을 절감하기 위한 에너지성능평가 모의연구를 수행하였다. 0.5[MW]급 마이크로 가스터빈을 설치한 후 에너지 성능분석을 한 결과 터빈에서의 발전효율은 30[%]이며, 전기는 건물에서 사용되는 조명에너지 뿐만 아니라 전체 전기에너지의 40[%]을 절감할 수 있는 것으로 분석되었다. 또한 터빈에서 발전되는 전기량과 배열을 냉난방에너지원으로 이용할 경우 전체 시스템효율은 70[%]로 상승할 뿐만 아니라 난방에너지의 56[%], 냉방에너지의 67[%]를 절감할 수 있는 것으로 분석되었으며 현가등가법에 의한 시스템 투자회수 기간이 약 9년으로 분석되었다.

• 한국표면공학회지
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• 제37권6호
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• pp.307-312
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• 2004

Extensive efforts have been made in an attempt to utilize photocatalytic properties of $TiO_2$ in visible range. $TiO_2$ and TiO-N thin films were made by the DC reactive magnetron sputtering method at $300^{\circ}C$. Various gases (Ar, $O_2$ and $N_2$) were used and Ti target was impressed by 0.6 kW-5.8 kW power range. The hysteresis phenomenon of the $TiO_2$ thin film as a function of the discharge voltage characteristic was observed to be higher as applied power increases. That of TiO-N thin film was occurred at the 5.8 kW power. The cross section and surface roughness of thin films were observed by FE-SEM and AFM. Average surface roughness of TiO-N thin film was observed as $15.9\AA$ and that of $TiO_2$ as $13.2\AA$. The crystal phases of both $TiO_2$ and TiO-N thin films were found to be anatase structure. The atomic $\beta$-N (396 eV peak in N 1s XPS) was shown in the rutile crystal of TiO-N and was considered acting as the origin of wavelength shift to the visible light.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.414-415
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• 2005

A solar cell is an element to transform the solar light energy into the electric energy in a moment. The single crystal element of high quality on which many studies were conducted in the past has a high efficiency of energy transformation, but its price competitiveness is so poor that it has failed to be popularized However, recently, in terms of an environment-friendly alternative energy, studies on applicability of the polycrystal solar cell have been actively under way. Among subject substances for such solar cell, $CuInSe_2$ has several good physical properties so that the greatest attention is paid to it as an optical absorption layer material for a low-cost solar cell of high efficiency. In order to manufacture the $CuInSe_2$ compound thin film, the unit element was deposited by using the sputtering method and the evaporation method and the heat treatment process was used in an electric furnace. Thereby, we intended to get a single-phase $CuInSe_2$ compound thin film.

• 대한기계학회논문집B
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• 제30권5호
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• pp.413-421
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• 2006

The bubble dynamics induced by direct laser heating is experimentally analyzed as a first step to assess the technical feasibility of laser-based ink-jet technology. To understand the interaction between laser light and ink, the absorption spectrum is measured for various ink colors and concentrations. The hydrodynamics of laser-generated bubbles is examined by the laser-flash photography. When an Ar ion laser pulse (wavelength 488 nm) with an output power up to 600 mW is incident on the ink solution through a transparent window, a hemispherical bubble with a diameter up to ${\sim}100{\mu}m$ can be formed with a lifetime in a few tens of microsecond depending on the laser power and the focal-spot size. Parametric study has been performed to reveal the effect of laser pulse width, output power, ink concentration, and color on the bubble dynamics. The results show that the bubble generated by a laser pulse is largely similar to that produced by a thin-film heater. Consequently, the present work demonstrates the feasibility of developing a laser-actuated droplet generation mechanism for applications in ink-jet print heads. Furthermore, the results of this work indicate that the droplet generation frequency is likely to be further increased by optimizing the process parameters.

• Food Science and Biotechnology
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• 제17권6호
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• pp.1254-1260
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• 2008

The aim of the present study was to prepare nanosample of fucoidan using lecithin as encapsulated material and to investigate the anticancer and immunomodulatory activity of nanoparticle in vitro. The nanoparticles have been characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Confocal microscopy confirmed the internalization of the fucoidan conjugates into the immune cells. The uptake of nanoparticles was confirmed with confocal microscopy demonstrating their localization in the cells. The anticancer activity was increased over 5-10% in different cancer cells of fucoidan nanoparticle as compare with fucoidan. The human B and T cells growth and the secretion of interleukin-6 and tumor necrosis factor-a from B cell were also improved by fucoidan nanoparticle because of the rapid absorption of nanoparticle into the cells as compare to fucoidan. At 0.6 mg/mL concentrations, the fucoidan nanoparticle showed better activity than 1.0 mg/mL concentration in T cell growth because the cells reached their saturation capacity. When the fucoidan was encapsulated in lecithin, its anticancer as well as its immunomodulatory activity proved to be superior from that of itself in pure form.

• 한국염색가공학회지
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• 제8권3호
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• pp.8-15
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• 1996

Three pieces of cotton fabrics used for this study were exhumed in the Mt.Moo Deung near Kwang Ju in 1965. The fabrics were remains of Jang Heung Lim Si-the nephew's wife of General Kim Deok Ryeong. It was reported that Jang Heung Lim Si died in 1615. The cotton fabrics were classified into three, A, B and C, according to their color. The fabric A was inherent color of cotton, the fabric B was that of light brown and the fabric C was that of dark brown. The physical and chemical characteristics of the cotton fabrics were examined. In the meantime the construction of cotton fabrics and traditional dyeing of Yi dynasty were studied through various records. The results were as follows: 1. According to electromicroscopic examination, the lumen in the cotton fiber had not been developed enough, therefore the quality of cotton at that time was supposed to be not so excellent. 2. The results of chemical analysis indicated that: (1) While the copper number of the cotton fabric A was similar to that of bleached cotton, that of the fabric C was extremely high. (2) The amount of methylene blue absorption was much more than that of normal cotton. (3) The content of cellulose was less than that of normal cotton. (4) The degree of polymerization was less than that of normal cotton. From the results mentioned above, it was concluded that the cotton fabrics were oxidized slowly in the closed lime coffin for a long period of time. From this process of oxidization and deterioration, the degree of polymerization was decreased through depolymerization, and carboxyl groups were produced by the oxidization at reducing end groups. 3. It was confirmed that the cotton fabric C was dyed by the juice of immature persimmon. Thus, it was inferred that the large amount of copper number of cotton fabric C was derived from phenolic OH groups of tannins having high reducing properties in persimmon.

• Bulletin of the Korean Chemical Society
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• 제16권12호
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• pp.1193-1203
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• 1995

In this work, we focused on the setup of the tools for the analysis of the final rotational state distribution of photofragments in vibrational predissociations of triatomic van der Waals molecules A-B2. We found that reflection principle used for the direct photodissociation processes can also be applied to find out the final rotational state distributions for indirect photodissociation processes. The quantity which represents the strength of rovibrational coupling between the quasi-bound state and the final state is reflected into the mirror of the classical angular momentum function, instead of the initial state before light absorption used in the reflection principle of direct processes. The sign change in the first derivative of the interaction potential with respect to the bond distance of B2 is found to be the source of the binodal structures in the final rotational distributions of photofragments in the model system studied in this work. In MQDT analysis, short range eigenchannel basis functions were found to be localized in angle, in the previous work [Lee, C.W. Bull. Korean Chem. Soc. 1995, 16, 957.] and may be called angle functions. Angle functions enjoy simple geometrical structures which have simple functional relations with the final state distributions of photofragments. Two processes take place along the angle functions which resemble the quasi-bound state and dominate over other processes. Two such angle functions are found to be not only localized angularly but also localized either one of ends of B2 in motions along the bond of B2. These dominating photodissociation processes, however, cancel each other. This cancellation causes photodissociation to depend sensitively on the interaction potential at other angles than the dominant one. Part of potential surface where much larger torque exists can now play an important role in photodissociation. MQDT also enables us to see which processes play important roles after cancellation. This is done by examining the amounts of time delayed by asymptotic eigenchannels.

• 한국염색가공학회지
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• 제31권3호
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• pp.135-146
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• 2019

A series of azo based disperse dyes were synthesized and applied to polyester(PET) fiber in supercritical carbon dioxide($ScCO_2$). Various aniline derivatives were used as diazo component and coupled with glycine ethylester or carbonic acid ethylester derivatives to give azo based disperse dyes. Depending on the various diazo substituents, absorption maxima varied from 415 to 529nm in acetone. Dyeing in $ScCO_2$ was carried out at $120^{\circ}C$ and 250bar pressure for 2hrs with 0.5% o.w.f. of dye concentration. Dyed PET fiber had excellent brightness and good light, washing and perspiration(acid/alkali) fastness properties.

• 한국광학회지
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• 제31권1호
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• pp.37-44
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• 2020

본 연구에서는 기본적인 평면 태양 전지 구조에 1차원 주기를 가지는 에미터 전극 배치를 통해 광학 및 전기적 효율을 최적화하는 설계방법을 제안한다. 에미터 전극의 주기가 줄어들면 애퍼처 비율이 감소해 빛 흡수율이 줄어들어 태양 전지 성능 저하에 영향을 끼친다. 본 연구에서는 시뮬레이션을 통해 가장 간단한 평판형 태양 전지 구조 내에서 에미터 전극 배열의 최적안을 제시하였다. 광학적 측면에서 에미터 전극이 없이 광흡수층 전면에서의 광흡수를 하는 레퍼런스 소자와 성능이 유사한 조건을 도출했다. 그리고 광흡수 및 전기적 효율 측면을 모두 고려하여 가장 효과적인 전극 구조를 제안하였다. 본 연구 결과는 광전 변환으로 생성된 전하를 전극으로 가장 효율적으로 전달할 수 있는 구조를 제안함으로써, 대체 에너지원에서 큰 비중을 차지하고 있는 태양 전지의 활용성을 높이는데 기여할 것이다.