• Title/Summary/Keyword: paramagnetic

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Magnetism in the Layered Structure Compound (C_18H_37NH_3)_2 MNCL_4

  • Lee, K. W.;Lee, C. H.;C. Rhee;Lee, Cheol-Eui;J. K. Kang;Lee, K.-S.
    • Journal of Magnetics
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    • v.2 no.4
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    • pp.126-129
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    • 1997
  • We have studied magnetostructural phase transitions in the perovskite-type layered structure compound (C18H37NH3)2 MnCl4 by means of electron paramagnetic resonance (EPR) and superconducting quantum interference device (SQUID) measurements. Distinct slopes were observed in the linear temperature dependences of the Mn++ EPR linewidth in the low and high temperature phases. Besides, linewidth anomalies at the transition temperatures sensitively reflect the magnetic changes arising from the MnCl6 octahedra.

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Valence State of the Sm Metal

  • Jang, Y.R.;Min, Byung-Il
    • Journal of Magnetics
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    • v.3 no.1
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    • pp.1-3
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    • 1998
  • Valence state of the Sm metal is investigated using the total energy linearized muffin-tin orbital (LMTO) band method for the observed Sm-type crystal structure. We have considered both the relativistic and the semi-relativistic description of 4f-core electrons. We have found that, in the paramagnetic phase of bulk Sm, the trivalent valence state is more stable at the observed lattice constant than the divalent valence state.

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Interaction of Cytochrome c and $Mn^{2+}$ -Cytochrome c Peroxidase

  • Kim, Mun-kyoung;M. Kwon;Kim, K.;Sanghwa Han
    • Proceedings of the Korean Biophysical Society Conference
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    • 1999.06a
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    • pp.44-44
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    • 1999
  • Yeast cytochrome c peroxidase (CcP) was cloned and overexpressed in E. coli, and purified by a Ni$^{2+}$-affinity column. HoloCcP was obtained by reconstituting apoCcP with Mn$^{3+}$-protoporphyrin IX (MnPP). Electron paramagnetic resonance (EPR) spectra of spin-labeled holoCcP showed a slightly more immobilized signal than spin-labeled apoCcP.(omitted)

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Magnetic Force Control Technique for Recycling and Environmental Preservation

  • Nishijima, Shigheiro
    • Progress in Superconductivity and Cryogenics
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    • v.14 no.4
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    • pp.1-4
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    • 2012
  • The applicability of the two types of magnetic separation system, high gradient magnetic separation (HGMS) and Magneto Archimedes method were studied considering the magnetic susceptibility of targeted substances. It was noted that the combination of the two methods can control the almost all the substances, paramagnetic and diamagnetic in addition to ferromagnetic substances. The principle of the methods was given and the conceput of the magnet force control technology is discussed. The practical applications of the technique were introduced together with the new application of HGMS.

The NMR Pseudocontact Shift of Tetrahedral and Pseudo-Tetrahedral Complex of Cu(II)

  • Kim, Dong Hui;Lee, Gi Hak
    • Bulletin of the Korean Chemical Society
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    • v.17 no.1
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    • pp.69-72
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    • 1996
  • The NMR dipolar shift in tetrahedral and tetragonally-distorted tetrahedral complexes for Cu(Ⅱ) has been calculated adopting nonmultipole expansion method. The exact solution of ΔB/B(ppm) is exactly in agreement with multipolar results when R, the distance between the paramagnetic ion and the nucleus, is larger than 0.2 nm. The major contribution to the dipolar shift arises from 1/R3 term but the other terms, 1/R5 and 1/R7, contribute significantly to the pseudocontact shift when R is shorter than 0.5 nm. The shift is mainly due to the 3d orbitals and sensitive to distortion parameters at short range of R.

Contact-Only and Dipolar-Only Mixtures of Lanthanide NMR Shift Reagents

  • Lee, Man-Ho
    • Bulletin of the Korean Chemical Society
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    • v.7 no.6
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    • pp.433-438
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    • 1986
  • Two new types of NMR shift reagents, one giving dipolar-only and the other giving contact-only shifts, can be prepared simply by mixing two appropriate $Ln(fod)_3$(Ln = Pr, Nd, Eu, and Yb) reagents in certain ratios. The $^1H$ and $^{13}C$ NMR spectra of pyridine-type substrates, quinoline and isoquinoline, whose paramagnetic shifts are normally a composite of contact and dipolar contributions with single lanthanide shift reagents, show the feasibility of this approach.

Syntheses of Piperidinyloxyl Diradicals Containing Squaric Acid Moieties and Their Magnetic Properties

  • Jeong Soo Kim;Lothar Dulog
    • Bulletin of the Korean Chemical Society
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    • v.14 no.4
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    • pp.465-468
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    • 1993
  • Four compounds containing two 2,2,6,6-tetramethylpiperidin-1-yloxyl radicals were synthesized. They are all chemically bonded with squaric moieties. The diradical compounds show fundamentally the paramagnetic behaviors satisfying the theoretical magnetic susceptibility according to Curie's law. A diradical compound of salf-form 4 however shows a relatively strong antiferromagnetic interaction in comparison with other reported organic radicals. The antiferromagnetic interaction of diradical 4 approximates a value of J/k= -50 K by the theoretical analysis of its temperature dependence.

ESR and Magnetization Study of $La_0.7Ca_0.3MnO_3$

  • Joh, Keon Woo;Lee, Chang Hoon;Lee, Cheol Eui;Jeong, Yoon Hee
    • Journal of Magnetics
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    • v.5 no.1
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    • pp.9-12
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    • 2000
  • Electron spin resonance and magnetization measurements were carried out on $La_0.7Ca_0.3MnO_3$ in the ferromagnetic as well as paramagnetic phases. Evidence of an inhomogeneous magnetic structure, consisting of ferro-magnetic microregions embedded in an antiferromagnetic matrix near $T_c$, as well as similar local magnetic structures above and below $T_c$, were found.

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