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1

Synthesis and Characterization of a Water-Soluble Ionic Polyacetylene Derivative

100%

Gal Y., Jin S., Park J., Lim K.

Acta Physica Polonica A

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2016

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vol. 129

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issue 4

642-646

EN

A new water-soluble ionic polyacetylene was synthesized by the acid-catalyzed polymerization of 2-ethynylpyridine using acrylic acid. The polymerization proceeded well to give a high yield of polymer. The acetylenic C ≡ C bond stretching (2110 cm¯¹) and acetylenic ≡ C-H bond stretching (3293 cm¯¹) peaks of 2-ethynylpyridine monomer were not seen in the FT-IR spectrum of polymer. The electro-optical and electrical properties of the ionic polyacetylene were measured and discussed. The resulting polymer showed strong maximum at 513 nm in the UV-Visible absorption, which is corresponding to photon energy of 2.42 eV. The energy gap width of polymer was estimated to be of 2.08 eV. It was observed that the electrochemical process of polymer is reproducible in the potential range of -1.80 to 1.60 V vs Ag/AgNO₃. HOMO and LUMO levels of polymer were 4.85 eV and 2.77 eV, respectively.

2

Evolution Of Precipitate Morphology During Extrusion In Mg ZK60A Alloy

88%

Park J., Ahn B., Jung K. H., Lee G. A., Kawasaki M.

Archives of Metallurgy and Materials

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2015

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issue 2

3

Frustrated Zig-Zag Spin Chains Formed by Hydrogen Bonds in [Cu(H₂O)(OH)(tmen)]₂[Pd(CN)₄]·2H₂O

76%

Čižmár E., Orendáčová A., Orendáč M., Kuchár J., Feher A., Park J., Meisel M.

Acta Physica Polonica A

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2017

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vol. 131

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issue 4

940-942

EN

The magnetic properties of the novel dimeric compound [Cu(H₂O)(OH)(tmen)]₂[Pd(CN)₄]·2H₂O (tmen=N,N,N',N'-tetramethylethylenediamine) with modulated crystal structure were studied in the temperature range from 95 mK to 300 K. Magnetic measurements revealed a presence of weak antiferromagnetic exchange coupling in the compound. The temperature dependence of specific heat is characterized by the presence of a Schottky-like maximum at 0.47 K and a λ-anomaly at 0.28 K, indicating the formation of long-range order in the system. The comparison of the experimental data with theoretical predictions revealed the presence of antiferromagnetic intradimer exchange coupling J/k_{B}= -1.2 K and interdimer coupling of a similar strength mediated via hydrogen bonds between dimeric units forming a frustrated magnetic zig-zag chain structure.

4

The Effect Of Grain Size On The Mechanical Properties Of Aluminum

76%

Jeong G., Park J., Nam S., Shin S.-E., Shin J., Bae D., Choi H.

Archives of Metallurgy and Materials

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2015

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issue 2

5

CuBr_2(C_{10}H_8N_2) - S = 1/2 Two-Dimensional Rectangular Heisenberg Antiferromagnet

64%

Čižmár E., Kajňaková M., Orendáčová A., Orendáč M., Feher A., Anders A., Park J., Meisel M.

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issue 5

973-974

EN

Magnetic susceptibility and X-band electron spin resonance study of a two-dimensional Heisenberg antiferromagnetic system CuBr_2(bipy), where bipy = C_{10}H_8N_2 is 4,4'-bipyridyl, has been performed in the temperature range from 300 K down to 2 K. A rhombic anisotropy of the g-factor was obtained from X-band EPR measurements with g_{x} = 2.037, g_{y} = 2.100 and g_{z} = 2.219. The temperature dependence of the magnetic susceptibility with a round maximum observed at 28 K suggests antiferromagnetic type of short-range order. No signature of the magnetic long-range order in studied compound was observed. The comparison of the magnetic susceptibility data with a two-dimensional rectangular Heisenberg model yields the values of intralayer exchange couplings J/k_{B} = - 47 K and J'/k_{B} = - 9.4 K.

6

Magnetic Response of Mn(III)F(salen) at Low Temperatures

52%

Park J., Risset O., Shiddiq M., Peprah M., Knowles E., Andrus M., Beedle C., Ehlers G., Podlesnyak A., Čižmár E., Nagler S., Hill S., Talham D., Meisel M.

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vol. 126

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issue 1

228-229

EN

The low temperature magnetic response of Mn(III)F(salen), salen = H_{14}C_{16}N_{2}O_{2}, an S=2 linear-chain system, has been studied. Using a single crystal with the field applied perpendicular to the chain direction, torque magnetometry, down to 20 mK and up to 18 T, revealed a feature at 3.8 T when T ≤ 400 mK. ESR ( ≈200 GHz) studies, using single crystals at 4 K and in 5 T, have not detected any signal. In 10 mT, the temperature dependence of the susceptibility of powder-like samples can be reasonably fit when J/k_{B}=50 K and g=2. In addition, these data are unchanged for P ≤1.0 GPa. Using a randomly-oriented, powder-like, deuterated (12 of 14 H replaced by D) sample of 2.2 g at 270 mK, neutron scattering data, acquired with the Cold Neutron Chopper Spectrometer at the Spallation Neutron Source, show several well defined excitations that may be from the zero-field energy levels of antiferromagnetic S=2 spins with g=2, J/k_{B}=50 K, D/k_{B}=2.8 K, and E/k_{B}=0.5 K.

Refine search results

Synthesis and Characterization of a Water-Soluble Ionic Polyacetylene Derivative

Evolution Of Precipitate Morphology During Extrusion In Mg ZK60A Alloy

Frustrated Zig-Zag Spin Chains Formed by Hydrogen Bonds in [Cu(H₂O)(OH)(tmen)]₂[Pd(CN)₄]·2H₂O

The Effect Of Grain Size On The Mechanical Properties Of Aluminum

CuBr_2(C_{10}H_8N_2) - S = 1/2 Two-Dimensional Rectangular Heisenberg Antiferromagnet

Magnetic Response of Mn(III)F(salen) at Low Temperatures