도핑온도에 따른 폴리아날린 필름의 전기전도도

유광선,여철현,Ryu, Kwang Sun,Yo, Chul Hyun 대한화학회 2001 대한화학회지 Vol.45 No.3

$Sr_{1+x}Ho_{1-x}FeO_{4-y}$계의 비화학량론적 조성과 그 물성에 관한 연구

유광선,유광현,노권선,여철현,Kwang Sun Ryu,Kwang Hyun Ryu,Kwon Sun Roh,Chul Hyun Yo 대한화학회 1993 대한화학회지 Vol.37 No.11

$K_2NiF_4$형 구조를 갖는 $Sr_{1+x}Ho_{1-x}FeO_{4-y}$ (x = 0.00, 0.25, 0.50, 0.75 및 1.00) 고용체계를 대기압과 1550$^{\circ}$C에서 제조하였다. 이 시료들의 X-선 회절도는 전 x 영역에서 모든 시료와 결정학적 상이 정방정계임을 나타내고 있다. 격자부피는 $Sr^{2+}$ 이온이 치환되는 양이 증가함에 따라 계속적으로 증가한다. 전체 철이온에 대한$ Fe^{4+}$ 이온의 몰비인${\tau}$</TE>값은 시료의 Mohr 염 적정으로 결정하였으며 x값과 ${\tau}$</TE>값으로부터 산소비화학량인 y값을 계산하였다. ${\tau}$</TE>값과 y값은 x값의 증가에 따라서 증가함을 알 수 있었다. x값, ${\tau}$</TE>값 y값을 일반식 $Sr_{1+x}Ho_{1-x}Fe^3_{1-}\;^+_{\tau}Fe_{\tau}^{4+}O_{4-y}$에 대입하여 비화학량론적 화학식을 결정하였다. Mossbauer 스펙트라는 $Fe^{3+}$ 이온과 $Fe^{4+}$ 이온의 혼합원자가 상태와 배위상태를 나타낸다. 각 시료들의 자기적 성질은 상온에서 상자성임을 알 수 있다. 전기전도도는 1.0 ~ 1 ${\times}\;10^{-9}{\Omega}^{-1}cm^{-1}$의 범위의 반도체 영역에서 변한다. 전기전도도의 활성화 에너지는${\tau}$</TE>값이 증가함에 따라 감소함을 알 수 있다. 전도성 메카니즘은 $Fe^{3+}$ 와 $Fe^{4+}$ 이온간에 전도성 전자의 건너뜀 모델로 설명되어야 한다. The series of solid solutions in the $Sr_{1+x}Ho_{1-x}FeO_{4-y}$ (x = 0.00, 0.25, 0.50, 0.75 and 1.00) systems with $K_2NiF_4$ type structure have been prepared at 1550$^{\circ}$C under an atmospheric air pressure. The X-ray powder diffraction spectra of these samples assign that the crystallographic phases are tetragonal system over the whole x range. The lattice volume was increased with increasing the substitution amount of the $Sr^{2+}$ ion. The mole ratio of the $Fe^{4+}$ ion to total iron ions or ${\tau}$ value has been determined by Mohr salt titration of the sample and then the y value was calculated from x and ${\tau}$ values. The ${\tau}$ and y values have been increased with x values. The nonstoichiometric chemical formula are formulated from the general formula of $Sr_{1+x}Ho_{1-x}Fe^3_{1-}\;^+_{\tau}Fe_{\tau}^{4+}O_{4-y}$ replaced by x,${\tau}$ and y values. Mossbauer spectra show the mixed valence state and coordination state of $Fe^{3+}\;and\;Fe^{4+}$ ions. It is found out that the magnetic property of the samples is paramagnetic at room temperature. Electrical conductivity varied within the semiconductivity range of 1.0 to 1 ${\times}\;10^{-9}{\Omega}^{-1}cm^{-1}$. Activation energy of the electrical conductivity was decreased with the $\tau$ value. The conduction mechanism should be explained by the hopping model of the conduction electrons between the valence states of $Fe^{3+}\;and\;Fe^{4+}$ ions.

이동식 크레인 붐의 최적설계

유광선,박정완,히다카 신이치,한석영,Yoo, Kwang-Seon,Park, Jeong-Wan,Sinichi, Hidaka,Han, Seog-Young 한국생산제조학회 2010 한국생산제조학회지 Vol.26 No.1

Optimum design of movable hydraulic crane's booms for weight reduction was performed in this study. Since the boom weight of the present used booms is very heavy, it is needed to make them lighter structure as possible as we can. Optimum design was performed for the booms by changing from the hexagonal cross section to triangular truss structure under the conditions, which are the allowable stress for the present cross section must be maintained, and the optimized weight must be minimized. CATIAV5 was used for stress analysis and design variables were established as the height and width of the triangular truss structure. As the results, it is found that the height of the truss structure is increased in proportion to the height of the booms and the maximum stress for optimal truss structure was obtained as 412MPa, which is lower than the allowable stress for the present hexagonal cross section. The optimized weight of the booms is reduced to about 19.88% comparing to the original weight.

고집광 태양광 발전을 위한 광학시스템 렌즈 개발

유광선(Ryu Kwang-sun),차원호(Cha Won-ho),신구환(Shin Goo-hwan),조희근(Cho HeeKeun),김용식(Kim Young-sik),강성원(Kang Seong-won),강기환(Kang Gi-Hwan) 한국태양에너지학회 2011 한국태양에너지학회 논문집 Vol.31 No.2

The artificial increase in the solar intensity incident on solar cells using lenses or mirrors can allow solar cells to generate equivalent power with a lower cost. There are two types of concentration optics for solar energy conversion. One is to use mirrors, and the other is to use Fresnel lenses. The gains that can be achieved with a Fresnel lens or a parabolic mirror are compared. The result showed the gains are comparable and the two configurations were developed competitively. In application areas of Fresnel lenses as solar concentrators, several variations of design were devised and tested. Some PV systems still use commercially available flat Fresnel lenses as concentrators. A convex linear Fresnel lens to improve the concentration ratio and the efficiency is devised and flat linear Fresnel lens in thermal energy collection is utilized. In this study, we designed and optimized flat Fresnel lens and the ‘light pipe’ to develop 500X concentrated solar PV system. In the process, we compare the transmission efficiencies according to groove types. We performed rigorous ray tracing simulation of the flat Fresnel lenses. The computer aided simulation showed the ‘grooves in case’ has the better efficiency than that of ‘grooves out case’. Based on the ray-trace results we designed and manufactured sample Fresnel lenses. The optical performance were measured and compared with ray-trace results. Finally, the optical efficiency was measured to be above 75%. All the design and manufacturing were performed based on that InGaP/InGaAs/Ge triple junction solar cell is used to convert the photon energy to electrical power. Field test will be made and analyzed in the near future.

이동식 크레인 붐의 최적설계

유광선(Kwang seon Yoo),박정완(Jeong Wan Park),히다카 신이치(Hidaka Sinichi),한석영(Seog young Han) 한국생산제조학회 2010 한국생산제조학회지 Vol.19 No.6

Optimum design of movable hydraulic crane's booms for weight reduction was performed in this study. Since the boom weight of the present used booms is very heavy, it is needed to make them lighter structure as possible as we can. Optimum design was performed for the booms by changing from the hexagonal cross section to triangular truss structure under the conditions, which are the allowable stress for the present cross section must be maintained, and the optimized weight must be minimized. CATIAV5 was used for stress analysis and design variables were established as the height and width of the triangular truss structure. As the results, it is found that the height of the truss structure is increased in proportion to the height of the booms and the maximum stress for optimal truss structure was obtained as 412㎫, which is lower than the allowable stress for the present hexagonal cross section. The optimized weight of the booms is reduced to about 19.88% comparing to the original weight.

고집광 태양광 발전을 위한 렌즈 및 광 파이프 특성 시뮬레이션

유광선(Ryu Kwang-Sun),신구환(Shin Goo-Hwan),차원호(Cha Won-Ho),명로훈(Myung Noh-Hoon),김용식(Kim Young-Sik),정호윤(Chung Ho-Yoon),김동균(Kim Dong Kyun),강기환(Kang Gi-Hwan) 한국태양에너지학회 2011 한국태양에너지학회 학술대회논문집 Vol.2011 No.4

The artificial increase in the solar intensity incident on solar cells using lenses or mirrors can allow solar cells to generate equivalent power with a lower cost. In application areas of Fresnel lenses as solar concentrators, several variations of design were devised and tested. Some PV systems still use commercially available flat Fresnel lenses as concentrators. In this study, we designed and optimized flat Fresnel lens and the 'light pipe' to develop 500X concentrated solar PV system. We performed rigorous ray tracing simulation of the flat Fresnel lens and light-pipe. The lightpipe can play imporatant roles of redistributing solar energy at the solar cell and increase the mechanical tolerance so that it can increase the lifetime of the high-concentration solar PV system and decrease the cost of manufacturing. To investigate the sensitivity of the solar power generated by the concentrated solar PV according to the performance of lens and light pipe, we performed ray tracing and executed a simulation of electrical performance of the solar cell when it is exposed to the non-uniform illumination. We could conclude that we can generate 95 % or more energy compared with the energy that can be generated by perfectly uniform illumination once the total energy is given the same.

혼합원자가 Sr$_{1+x}Er _{1-x} FeO _{4-y}$ 훼라이트계의 비화학양론과 물성연구

여철현,유광선,편무실,이성주,최중길,Chul Hyun Yo,Kwang Sun Ryu,Mu Sil Pyun,Sung Joo Lee,Joong Gill Choi 대한화학회 1991 대한화학회지 Vol.35 No.2

$K_2NiF_4$형 층상 구조를 갖는 Sr$_{1+x}Er _{1-x} FeO _{4-y}$계에서 x = 0.00, 0.25, 0.50, 0.75 및 1.00인 비화학양론적 화합물 고용체를 1350$^{\circ}$C 대기압에서 제조하였다. X-선 회절 분석결과로 모든 조성에서 고용체의 결정 구조는 준정방정계(pseudo-tetragonal system)였다. 비화학양론적 조성식은 Mohr염 분석으로 결정하였다. Fe$^{4+}$ 이온의 양은 x값이 0.50까지 증가함에 따라 증가하다가 다시 감소하였고 산소 비화학량은 증가하였다. 도한 시료의 Fe$^{3+}$와 Fe$^{4+}$의 혼합원자가 상태를 298K에서 Mossbauer 분광분석으로 확인할 수 있었다. 전기전도도 측정 결과에 따르면 전기전도도는 반도체 영역인 10-2 ∼ 10-7(${\Omega}$-1cm-1)범위에서 변하였고, 활성화에너지는 Fe$^{4+}$의 몰비인 ${\tau}$값이 증가함에 따라 감소하였다. 전기전도성 메카니즘은 Fe$^{3+}$와 Fe$^{4+}$의 혼합원자가 상태간의 전도성전자 건너뜀 모델로 설명할 수 있다. Nonstoichiometric solid solutions of Sr$_{1+x}Er _{1-x} FeO _{4-y}$ system (x = 0.00, 0.25, 0.50, 0.75 and 1.00) with layered $K_2NiF_4$ type structure were prepared at 1350$^{\circ}$C under atmospheric pressure. By the analysis of X-ray diffraction, the crystallographic structures of the solid solution of all compositions were found to be pseudo-tetragonal system. Nonstoichiometric chemical formulas have been determined by Mohr salt analysis. It shows that the amount of Fe$^{4+}$ increases with increasing x up to 0.50 and then decreases, and the value of oxygen nonstoichiometry increases with increasing x value. Mixed valency states of Fe$^{3+}$ and Fe$^{4+}$ in the sample were identified again by Mossbauer spectroscopic analysis at 298 K. Electrical conductivity varied within the semiconductivity range of 10-2 ∼ 10-7(${\Omega}$-1cm-1), activation energy for electrical conduction decreased with the increment of the mole ratio of Fe$^{4+}$ or ${\tau}$ value. The conduction mechanism could be explained by the hopping model of the conduction electrons between the valency states of Fe$^{3+}$ and Fe$^{4+}$.

FIMS 타입의 우주관측용 원자외선분광기 광학설계

선광일,육인수,유광선,이대희,SEON KWANG-IL,YUK IN-SOO,RYU KWANG-SUN,LEE DAE-HEE 한국천문학회 2004 天文學論叢 Vol.19 No.1

An imaging spectrograph concept optimized for extended far-ultraviolet emission sources is presented. Although the design was originally developed for FIMS aboard the first Korean science satellite STSAT-l launched on September 27, 2003, no rigorous theoretical background of the spectrograph design has been published. The spectrograph design employs an off-axis parabolic cylinder mirror in front of a slit that guides lights to a diffraction grating. The concave grating provides moderate spatial resolution over a large field of view. This mapping capability is absent in most astronomical instruments but is crucial to the understanding of the nature of a variety of astrophysical phenomena. The aberration theory presented in this paper can be extended to holographic gratings in order to improve the spatial as well as the spectral resolutions.

비선형 정적 문제에 대한 벌군집 알고리즘의 적용

엄영섭(Young-Sop Eom),유광선(Kwang-Sun Yoo),김동연(Dong-Yeon Kim),박재용(Jae-Yong Park),한석영(Seog-Young Han) 한국생산제조학회 2010 한국공작기계학회 추계학술대회논문집 Vol.2010 No.-

In this paper, bee colony algorithm and finite element analysis are adopted for topology optimization of structural models undergoing large deformations. The objective is to obtain the stiffest structure with a certain amount of material, based on each element's contribution to the strain energy. Newton-Raphson method is used to calculate nonlinear problem. In order to prevent checkerboard pattern in the resulted optimum layout, the latest developed filter scheme is implemented. Cantilever beam was elected as numerical example. After solving example, it is found that the effectiveness and applicability of the proposed algorithm. The bee colony algorithm is well able to handle nonlinear topology optimization problems.

3차원 구조물에 대한 효율적인 신뢰성 해석법

엄영섭(Young-Sop Eom),유광선(Kwang-Sun Yoo),김동연(Dong-Yeon Kim),박재용(Jae-Yong Park),한석영(Seog-Young Han) 한국생산제조학회 2010 한국공작기계학회 추계학술대회논문집 Vol.2010 No.-

In this paper, reliability-based topology optimization (RBTO) for 3-D structures was performed by using bi-directional evolutionary structural optimization (BESO) and standard response surface method (SRSM). In order to get stable optimal topology, the latest developed filter scheme was implemented to BESO, and SRSM was used to generate an approximate limit state function. These results were compared with recently announced results of RBTO for the 2-D structures, and the differences between the results of 3-D and 2-D structures are considered. Cantilever beam and MBB beam were selected as numerical examples. From performing RBTO, it is found that the optimal topologies of DTO and RBTO for 2-D and 3-D MBB beams are obtained very differently. Especially, two-support member at the left hand side comes into being in the width direction. Therefore, it is known that RBTO for 3-D structures is necessary to be performed.