• 제목/요약/키워드: H atoms

검색결과 651건 처리시간 0.026초

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
    • 분석과학
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    • 제15권6호
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    • pp.540-549
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    • 2002
  • 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.

Structure and Heme-Independent Peroxidase Activity of a Fully-Coordinated Mononuclear Mn(II) Complex with a Schiff-Base Tripodal Ligand Containing Three Imidazole Groups

  • Sarkar, Shuranjan;Moon, Do-Hyun;Lah, Myoung-Soo;Lee, Hong-In
    • Bulletin of the Korean Chemical Society
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    • 제31권11호
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    • pp.3173-3179
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    • 2010
  • New complex $[Mn(II)H_{1.5}L]_2[Mn(II)H_3L]_2(ClO_4)_5{\cdot}3H_2O$ (1), where $H_3L$ is tris {2-(4-imidazolyl)methyliminoethyl} amine (imtren), has been prepared by reacting manganese(II) perchlorate hexahydrate with the imtren ligand in methanol. X-ray crystallographic study revealed that the imtren ligand hexadentately binds to Mn(II) ion through the three Schiff-base imine N atoms and three imidazole N atoms with a distorted octahedral geometry, and the apical tertiary amine N atom of the ligand pseudo-coordinates to Mn(II), forming overall a pseudo-seven coordination environment. The hydrogen-bonds between imidazole and imidazolate of $[Mn(II)H_{1.5}L]^{0.5+}$ complex ions are extended to build a 2D puckered network with trigonal voids. $[Mn(II)H_3L]^{2+}$ complex ions constitutes another extended 2D puckered layer without hydrogen bonds. Two layers are wedged each other to constitute overall stack of the crystal. Peroxidase activity of complex 1 was examined by observing the oxidation of 2,2'-azinobis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) with hydrogen peroxide in the presence of complex 1. Generation of $ABTS^{+{\cdot}}$ was observed by UV-vis and EPR spectroscopies, indicating that the complex 1, a fully-coordinated mononuclear Mn(II) complex with nitrogen-only ligand, has a heme-independent peroxidase activity.

Cyanide- and Phenoxo-Bridged Heterobimetallic Fe(III)-Mn(III) Coordination Polymer: Synthesis, Crystal Structures and Magnetic Properties

  • Zhang, Daopeng;Kong, Lingqian;Li, Yueyun;Wang, Ping;Chen, Xia
    • Bulletin of the Korean Chemical Society
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    • 제35권9호
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    • pp.2684-2688
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    • 2014
  • Two two-dimensional cyanide- and phenoxo-bridged heterometallic M(II)-Mn(III) (M = Ni, Pd) coordination polymers $\{[Mn(saltmen)]_4[Ni(CN)_4]\}(ClO_4)_2{\cdot}CH_3OH{\cdot}H_2O$ (1) and $\{[Mn(saltmen)]_4[Pd(CN)_4]\}(ClO_4)_2{\cdot}CH_3CN{\cdot}H_2O$ (2) ($saltmen^{2-}$ = N,N'-(1,1,2,2-tetramethylethylene)bis(salicylideneaminato)dianion) have been obtained by using $K_2[M(CN)_4]$ as building blocks and a salen-tpye Schiff-base manganese(III) compound as assembling segment. Single X-ray analysis reveals their isostrutural cyanide-bridged $MMn_4$ pentanuclear cationic structure. The four Schiff base manganese units of the pentanuclear entity are self-complementary through the phenoxo oxygen atoms from the neighboring complex, therefore forming cyanide- and phenoxo-bridged 2D sheet-like structure. Investigation over magnetic susceptibilities reveals the overall ferromagnetic coupling between the adjacent Mn(III) ions bridged by the phenoxo oxygen atoms with J = 2.13 and $2.21cm^{-1}$ for complexes 1 and 2, respectively.

Seeding Method를 이용한 인이 도우핑된 Amorphous-Si에서의 HSG형성 조건 (Hemispherical Grained Silicon formation Condition on In-Situ Phosphorous Doped Amorphous-Si Using The Seeding Method)

  • 정양희;강성준
    • 한국정보통신학회논문지
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    • 제5권6호
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    • pp.1128-1135
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    • 2001
  • 본 논문에서는 HSG형성을 위한 Si$_2$H$_{6}$의 조사와 어닐링을 통한 seeding method를 64Mbit DRAM에 적용하였다. 이 기술을 사용함으로서 인이 도우핑된 Amorphous 실리콘의 전극에 HSG grain 크기를 조절할 수 있었고, 이 새로운 HSG형성조건은 기존의 stack 캐패시터보다 약 2배의 정전용량을 확보할 수 있었다. 이와같은 방법을 이용한 HSG형성에서 인농도, 저장폴리 증착온도 및 HSG의 두께에 대한 공정 최적 조건으로는 각각 3.0-4.OE19atoms/㎤ , 53$0^{\circ}C$ 및 400$\AA$이었다. 이들 최적화된 공정조건으로 64M bit DRAM 캐패시터에 적용시 질화막의 두께 한계는 65$\AA$으로 확인되었다.

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Measurement of the excited Xe atoms density of matastable state$(1S_5)$ under various binary gas mixtures(Ne-Xe) by Laser Absorption Spectroscopy.

  • Lee, Jun-Ho;OH, P.Y.;Moon, M.W.;Ko, B.D.;Jeong, J.M.;Lee, H.J.;Choi, E.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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    • pp.1218-1220
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    • 2005
  • We have developed laser absorption spectroscopy system for the measurement of excited Xe atoms in micro-discharged AC-PDP plasma. In this study, we have measured the absorption signals for the $1S_5$ xenon metastable state in the PDP cell with the various gas mixtures of Ne-Xe(1%), Ne-Xe(4%) and Ne-Xe(10%) under fixed gas pressure of 350 Torr and the eletrode gap distance of 50um. It is found that the maximum excited xenon densities are $1.2^{\ast}10^{12}\;cm^{-3}$, $1.8^{\ast}10^{12}\;cm^{-3}$ and $2.7^{\ast}10^{12}cm^{-3}$ for gas mixtures of Ne-Xe(1%), Ne-Xe(4%) and Ne-Xe(10%) respectively, in this experiment.

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Hydrothermal Synthesis, Crystal Structure and EPR Property of Tetranuclear Copper(II) Cluster [Cu4OCl6(C14H12N2)4]

  • Jian, Fang-Fang;Zhao, Pu-Su;Wang, Huan-Xiang;Lu, Lu-De
    • Bulletin of the Korean Chemical Society
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    • 제25권5호
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    • pp.673-675
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    • 2004
  • The tetranuclear copper(II) cluster compound $[Cu_4OCl_6(C_{14}H_{12}N_2)_4]$ has been synthesized by hydrothermal reaction and studied by X-ray diffraction. The four copper(II) atoms locate four capsheaves of a tetrahedral skeletal structure and a oxygen atom as interstitial atom occupies the center position of the same tetrahedron, and each edge of the Cu-Cu tetrahedron is bridged by one ${\mu}_2$-Cl anion. The copper atom possesses slightly distorted trigonal bipyramidal geometry with three ${\mu}_2$-Cl atoms in equatorial position and the interstitial O atom and one N atom from 3-benzyl-benzimidazole ligand occupying axial position. The Cu-Cu distances are in the range of 3.0986-3.1162 ${\AA}$. The EPR spectrum suggested that the copper(II) ground state $d_{x2-y2}$ and the coordination geometry was trigonal bipyramidal.

The influences of film density on hydration of MgO protective layer in plasma display panel

  • Lee, Jung-Heon;Eun, Jae-Hwan;Park, Sun-Young;Kim, Soo-Gil;Kim, Hyeong-Joon
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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    • pp.228-231
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    • 2002
  • We report the effect of density of thin films on moisture adsorption and hydration of MgO thin film, usually used as a protective layer in AC-PDP After hydration, lots of hemispherical shaped clusters, $Mg(OH)_2$, formed on the surface of MgO thin films. However clusters formed on low-density thin films were bigger than those on high-density films. From ERD spectra, it seemed that the concentration of hydrogen was very high in the region 20 nm from the surface of MgO thin film. The low-density thin film had more hydrogen than high-density thin film. From simulation results of ERD and RBS it was found that hydration reaction also occurred in the inner part of the film. So diffusion of Mg atoms from the inner part of the film to the surface and $H_2O$ molecules from the surface to the inner part of the film is important. And because low density thin film has many short paths for diffusion of Mg atoms and $H_2O$ molecules, low-density thin film is more hydrated. So to suppress hydration of MgO thin films, high-density thin film is needed.

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