PEMFC의 효율적 시뮬레이션을 위한 Matlab/Simulink와 PSIM기반의 Co-Simulation

임채홍,이우택 국립7개대학공동논문집간행위원회 2005 공업기술연구 Vol.5 No.-

Fuel Cell system is expected to use widely in the near future. Proton Exchange Membrane Fuel Cell(PEMFC) system is broadly investigated due to low operating temperature and fast start up characteristics. To shorten the time and effort putting into development, the simulation procedure is needed, For Simulating Fuel Cell system, specified tools are necessary because Fuel Cell system consists of control system, power generation system and power conversion system. Matlab/Simulink is useful to simulate Fuel Cell's control algorithm and V-I characteristics. PSIM is useful to simulate Fuel Cell system's power conversions. This paper, focuses on Co-Simulation of PEMFC system using Matlab/Sumulink and PSIM. Co-Simulation is an effective method to simulate PEMFC's complicated characteristics.

폐철을 이용한 크롬(VI)의 환원적 제거

임우택,정용식,유건상,김종현,김영훈 7개 국립대학교 환경연구논문집 공동발행 위원회 2005 공업기술연구 Vol.5 No.-

Cr(VI) is a known toxic heavy metal which is found frequently in many industrial sites. Contaminates soil and ground water with Cr(VI) is a big enviromental concern due to the high toxicity. Permeable Reactive Barrier(PRB)is an innovative remedial technology intensively studied and developed recenty. The most popular PRB material is zero-valent iron which is environmentally favorable and cheap. Scrapped steels and precleaned scrapped steels were tested in this study for Cr(VI). Scrapped steels were precleaned wuth detergent, acetone, hexane.The precleaned scrapped steel showed relatively high reactivity for Cr(VI). The results indicate that the scrapped steel could be used as PRB material after proper pretreatments.

Crystallinity of large single crystals of FAU-type zeolites with a wide range of Si/Al ratios

Lim, Woo Taik,Seo, Sung Man,Okubo, Tatsuya,Park, Man Springer-Verlag 2011 Journal of porous materials Vol.18 No.3

Synthesis and Crystal Structure of Ag₄Br₄ Nanoclusters in the Sodalite Cavities of Fully K⁺-Exchanged Zeolite A (LTA)

Lim, Woo-Taik,Choi, Sik-Young,Kim, Bok-Jo,Kim, Chang-Min,Lee, In-Su,Kim, Seok-Han,Heo, Nam-Ho Korean Chemical Society 2005 Bulletin of the Korean Chemical Society Vol.26 No.7

$Ag_4Br_4$ nanoclusters have been synthesized in about 75% of the sodalite cavities of fully $K^+$-exchanged zeolite A (LTA). An additional KBr molecule is retained in each large cavity as part of a near square-planar $K_4Br^{3+}$ cation. A single crystal of $Ag_{12}$-A, prepared by the dynamic ion-exchange of $Na_{12}$-A with aqueous 0.05 M $AgNO_3$ and washed with $CH_3OH$, was placed in a stream of flowing 0.05 M KBr in $CH_3OH$ for two days. The crystal structure of the product ($K_9(K_4Br)Si_{12}Al_{12}O_{48}{\cdot}0.75Ag_4Br_4$, a = 12.186(1) $\AA$) was determined at 294 K by single-crystal X-ray diffraction in the space group Pm m. It was refined with all measured reflections to the final error index $R_1$ = 0.080 for the 99 reflections for which $F_o\;{\gt}\;4_{\sigma}\;(F_o)$. The thirteen $K^+$ ions per unit cell are found at three crystallographically distinct positions: eight $K^+$ ions in the large cavity fill the six-ring site, three $K^+$ ions fill the eight-rings, and two $K^+$ ions are opposite four-rings in the large cavity. One bromide ion per unit cell lies opposite a four-ring in the large cavity, held there by two eight-ring and two six-ring $K^+$ ions ($K_4Br^{3+}$). Three $Ag^+$ and three $Br^-$ions per unit cell are found on 3-fold axes in the sodalite unit, indicating the formation of nano-sized $Ag_4Br_4$ clusters (interpenetrating tetrahedra; symmetry $T_d$; diameter ca. 7.9 $\AA$) in 75% of the sodalite units. Each cluster (Ag-Br = 2.93(3) $\AA$) is held in place by the coordination of its four $Ag^+$ ions to the zeolite framework (each $Ag^+$ cation is 2.52(3) $\AA$ from three six-ring oxygens) and by the coordination of its four $Br^-$ ions to $K^+$ ions through six-rings (Br-K = 3.00(4) $\AA$).

Synthesis and Characterization of the Large Single Crystal of Fully K⁺-exchanged Zeolite X (FAU), |K₈₀|[Si₁₁₂Al₈₀O₃₈₄]-FAU (Si/Al=1.41)

Lim, Woo-Taik,Jeong, Gyo-Cheol,Park, Chang-Kun,Park, Jong-Sam,Kim, Young-Hun Korean Chemical Society 2007 Bulletin of the Korean Chemical Society Vol.28 No.1

Large colorless single crystals of sodium zeolite X, stoichiometry |Na80 |[Si112Al80O384]-FAU, with diameters up to 200 μm and Si/Al = 1.41 have been synthesized from gels with the composition of 2.40SiO2 : 2.00NaAlO2 : 7.52NaOH : 454H2O : 5.00TEA. One of these, a colorless octahedron about 200 μm in cross-section has been treated with aqueous 0.1 M KNO3 for the preparation of K+-exchanged zeolite X. The crystal structure of |K80|[Si112Al80O384]-FAU per unit cell, a = 24.838(4) A, dehydrated at 673 K and 1 × 10-6 Torr, has been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd at 294 K. The structure was refined using all intensities to the final error indices (using only the 707 reflections for which Fo > 4σ (Fo)) R1 = 0.075 (based on F) and R2 = 0.236 (based on F2). About 80 K+ ions per unit cell are found at an unusually large number of crystallographically distinct positions, eight. Eleven K+ ions are at the centers of double 6-rings (D6Rs, site I; K-O = 2.492(6) A and O-K-O (octahedral) = 88.45(22)o and 91.55(22)o). Site-I' position (in the sodalite cavities opposite D6Rs) is occupied by five K+ ions per unit cell; these K+ ions are recessed 1.92 A into the sodalite cavities from their 3-oxygen planes (K-O = 2.820(19) A, and O-K-O = 78.6(6)o). Twety-three K+ ions are found at three nonequivalent site II (in the supercage) with occupancies of 5, 9, and 9 ions; these K+ ions are recessed 0.43 A, 0.75 A, and 1.55 A, respectively, into the supercage from the three oxygens to which it is bound (K-O = 2.36(13) A, 2.45(13) A, and 2.710(13) A, O-K-O = 116.5(20)o, 110.1(17)o, and 90.4(6)o, respectively). The remaining sixteen, thirteen, and twelve K+ ions occupy three sites III' near triple 4-rings in the supercage (K-O = 2.64(3) A, 2.94(3) A, 2.73(5) A, 2.96(6) A, 3.06(4) A, and 3.08(3) A).

[Chemistry] Crystallographic Analysis of Ar Encapsulate within Cs₃ - A Zeolite

Woo Taik Lim,Bok Jo Kim,Jong Sam Park,Chang Hwan Chang,Sung Wook Jung,Nam Ho Heo 한국분석과학회 2002 분석과학 Vol.15 No.6

Crystallographic Analysis of Ar Encapsulate within Cs₃-A Zeolite

Lim, Woo Taik,Kim, Bok Jo,Park, Jong Sam,Chang, Chang Hwan,Jung, Sung Wook,Heo, Nam Ho The Korean Society of Analytical Science 2002 분석과학 Vol.15 No.6

The arrangement of encapsulated Ar atoms in the molecular-dimensioned cavities of fully dehydrated zeolite A of unit-cell composition $Cs_3Na_8HSi_{12}Al_{12}O_{48}$ ($Cs_3$-A) has been studied crystallographically to probe the confinement effect of guest species in microporous environment. Atoms of Ar were encapsulated in the cavities of $Cs_3$-A by treatment with 410 atm of Ar at $400^{\circ}C$ for two days, followed by cooling at room temperature. The crystal structure of $Cs_3Na_8H$-A(4Ar) ($P_e$ = 410 atm, $a=12.245(2){\AA}$, $R_1=0.0543$, and $R_2=0.0552$) has been determined by single crystal X-ray diffraction technique in the cubic space group $Pm\bar{3}m$ at 21 (1) $^{\circ}C$ and 1 atm. Encapsulated Ar atoms are distributed in three crystallographic distinct positions: 1.5 Ar atoms per unit cell opposite 6-rings, 1.5 opposite four-rings in the large cavity, and finally 1.0 in the sodalite-unit. The possible structures of argon clusters, such as $Ar_2$, $Ar_3$, and $Ar_4$, are proposed.

Synthesis, Characterization, and Application of ZeolitesA, X, andY

Woo Taik Lim,Sung Man Seo,Hu Sik Kim,Jae Myeong Lee,Dae Jun Moon,Min Ho Kang 한국암석학회 2007 한국암석학회 학술발표회 논문집 Vol.- No.-

Synthesis and Characterization of the Large Single Crystal of Fully K+-exchanged Zeolite X (FAU), |K80|[Si112Al80O384]-FAU (Si/Al = 1.41)

Woo Taik Lim*,Gyo Cheol Jeong,Chang Kun Park,Jong Sam Park,Young Hun Kim* 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.1

Large colorless single crystals of sodium zeolite X, stoichiometry |?Na80?|?[Si112Al80O384]-FAU, with diameters up to 200 mm and Si/Al = 1.41 have been synthesized from gels with the composition of 2.40SiO2 : 2.00NaAlO2 : 7.52NaOH : 454H2O : 5.00TEA. One of these, a colorless octahedron about 200 mm in cross-section has been treated with aqueous 0.1 M KNO3 for the preparation of K+-exchanged zeolite X. The crystal structure of |K80|[Si112Al80O384]-FAU per unit cell, a = 24.838(4) , dehydrated at 673 K and 1 10-6 Torr, has been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd at 294 K. The structure was refined using all intensities to the final error indices (using only the 707 reflections for which Fo > 4s(Fo)) R1 = 0.075 (based on F?) and R2 = 0.236 (based on F?2?). About 80 K+ ions per unit cell are found at an unusually large number of crystallographically distinct positions, eight. Eleven K+ ions are at the centers of double 6-rings (D6Rs, site I; K-O = 2.492(6) and O-K-O (octahedral) = 88.45(22)o and 91.55(22)o). Site-I' position (in the sodalite cavities opposite D6Rs) is occupied by five K+ ions per unit cell; these K+ ions are recessed 1.92 into the sodalite cavities from their 3-oxygen planes (K-O = 2.820(19) , and O-K-O = 78.6(6)o). Twety-three K+ ions are found at three nonequivalent site II (in the supercage) with occupancies of 5, 9, and 9 ions; these K+ ions are recessed 0.43 , 0.75 , and 1.55 , respectively, into the supercage from the three oxygens to which it is bound (K-O = 2.36(13) , 2.45(13) , and 2.710(13) , O-K-O = 116.5(20)o, 110.1(17)o, and 90.4(6)o, respectively). The remaining sixteen, thirteen, and twelve K+ ions occupy three sites III?' near triple 4-rings in the supercage (K-O = 2.64(3) , 2.94(3) , 2.73(5) , 2.96(6) , 3.06(4) , and 3.08(3) ).

Synthesis of Tellurium Sorption Complexes in Fully Dehydrated and Fully Ca²⁺-exchanged Zeolites A and X and their Single-crystal Structures

Lim, Woo-Taik,Park, Jong-Sam,Lee, Sang-Hoon,Jung, Ki-Jin,Heo, Nam-Ho Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.6

Single crystals of fully dehydrated and fully $Ca^{2+}$-exchanged zeolites A (|$Ca_6$|[$Si_{12}Al_{12}O_{48}$]-LTA) and X (|$Ca_{46}$| [$Si_{100}Al_{92}O_{384}$]-FAU) were brought into contact with Te in fine pyrex capillaries at 623 K and 673 K, respectively, for 5 days. Crystal structures of Te-sorbed $Ca^{2+}$-exchanged zeolites A and X have been determined by single-crystal X-ray diffraction techniques at 294 K in the cubic space group Pm$\overline{3}$ m (a = 12.288(2) $\AA$) and Fd $\overline{3}$ (a = 25.012(1) $\AA$), respectively. The crystal structures of pale red-brown |$Ca_6Te_3$|[$Si_{12}Al_{12}O_{48}$]-LTA and black coloured |$Ca_{46}Te_8$| [$Si_{100}Al_{92}O_{384}$]-FAU have been refined to the final error indices of $R_1/wR_2\;=\;0.1096/0.2768\;and\;R_1/wR_2$ = 0.1054/ 0.2979 with 204 and 282 reflections for which $F_o\;>\;4{\sigma}(F_o)$, respectively. In the structure of |Ca6Te3|[$Si_{12}Al_{12}O_{48}$]- LTA, 6 $Ca^{2+}$ ions per unit cell were found at one crystallographic positions, on 3-fold axes equipoints of opposite 6-rings. In |$Ca_{46}Te_8$|[$Si_{100}Al_{92}O_{384}$]-FAU, 46 $Ca^{2+}$ ions per unit cell were found at four crystallographically distinct positions: 3 $Ca^{2+}$ ions at Ca(1) fill the 16 equivalent positions of site I, 21 $Ca^{2+}$ ions at Ca(2) fill the 32 equivalent positions of site I’, 10 and 12 $Ca^{2+}$ ions at Ca(3) and Ca(4), respectively, fill the 32 equivalent positions of site II. The Te clusters are stabilized by interaction with cations and framework oxygen. In sodalite units, Te-Te distances of 2.86(10) and 2.69(4) $\AA$ in zeolites A and X, respectively exhibited strong covalent properties due to their interaction with $Ca^{2+}$ ions. On the other hand, in large cavity and supercage, those of 2.99(3) and 2.76(11) $\AA$ in zeolites A and X, respectively, showed ionic properties because alternative ionic interaction was formed through framework oxygen at one end and $Ca^{2+}$ cations at the other end.