• Bulletin of the Korean Chemical Society
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• v.9 no.2
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• pp.84-87
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• 1988

The Photophysical and photochemical properties of Ruthenium bipyridine with two long hydrocarbon chains, $[Ru(bipy)_2(dhbipy)]^{2+}$ and transient phenothiazine derivative cation radical $(PTD^+)$ in the cationic vesicle were studied. Transient absorption spectra of cation radical of phenothiazine derivative in the vesicle system containing the $Ru^{2+}$ complex, $[Ru(bipy)_2(dhbipy)]^{2+}$, (1) as sensitizer and phenothiazine derivative as electron donor was observed by XeCl excimer laser photolysis system. Thus the excited ruthenium complex would be quenched by phenothiazine derivative(PTD) reductively in the vesicle system. The quenching rate constant($K_Q$) of $Ru^{2+}$ with two long hydrocarbon chains in the vesicle by PTD was $9.6{\times}10^8M^{-1}S^{-1}$. The absorption decay kinetics showed that lifetime of phenothiazine derivative cation radical is a value in the 4-8m sec range.

• Bulletin of the Korean Chemical Society
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• v.8 no.3
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• pp.144-145
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• 1987

The relative stability as function of geometry in the rigid tricyclopropylcarbinyl cations with varied bond angle (${\alpha}$) between the plane of cyclopropane ring and the bond connecting cyclopropane ring to cationic carbon was examined by $^{19}F$ nmr spectroscopy. 7-p-Fluorophenyltricyclo[2.2.2.$0^{2,6}$]octan-7-yl(4) and 8-p-fluorophenyltricyclo[3.2.2.$0^{2,7}$]nonan-8-yl cation (8) were generated from corresponding tertiary alcohols under stable ion conditions, and their $^{19}F$ chemical shifts were compared with those of model compounds such as 7-nortricyclyl cation (3) and tricyclo[3.3.1.$0^{2,7}$]octan-8-yl cation (7). Consequently, it is concluded that the varied orientation of bond angle (${\alpha}$) within in the bisected conformation does not affect degree of the charge delocalization into cyclopropane ring.

• Bulletin of the Korean Chemical Society
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• v.14 no.6
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• pp.692-696
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• 1993

Prediction of retention times in transition metal-mandelate and transition metal-tartrate complex systems were studied on the cation exchanger. Plots of k' vs [mandelate] and k' vs [tartrate] were obtained under the condition of a constant competing cation concentration. The equation to predict the retention time of transition metal ion was derived from the ion exchange equilibria. Individual capacity factors (${k_1}',\;{k_2}'$) and stability constants ($K_1,\;K_2$) of the complexes were calculated from the non-linear least square method. Good resolution of the transition metals was predicted by the stepwise equation in the gradient method. The values of retention times from the calculation and the experiment agreed well each other.

• Bulletin of the Korean Chemical Society
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• v.17 no.5
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• pp.452-457
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• 1996

The effects caused by the ionization on the electronic structure and geometry on C60 are studied by the modified Su-Schriffer-Heeger (SSH) model Hamiltonian. After the ionization of C60, the bond structure of the singly charged C60 cation is deformed from Ih symmetry of the neutral C60 to D5d, C1, and C2, which is dependent upon the change of the electron-phonon coupling strength. The electronic structure of the C60+ cation ground state undergoes Jahn-Teller distortion in the weak electron-phonon coupling region, while self-localized states occur in the intermediate electron-phonon region, but delocalized electronic states appear again in the strong electron-phonon region. In the realistic strength of the electron-phonon coupling in C60, the bond structure of C60+ shows the layer structure of the bond distortion and a polaron-like state is formed.

• Bulletin of the Korean Chemical Society
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• v.18 no.6
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• pp.636-640
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• 1997

The structure and conformational behavior of the oxyanions of calix[4]arene have been studied by the NMR spectrum. The structure of the oxyanions of calix[4]arene was completely dependent upon the counter cation in present. All of the anions derived from in the presence of NaH and KH appear to exist as a cone conformation, whereas those produced with lithium cation such as n-butyllithium and LiOD show a more varied conformational behavior. The mono and tetraanions with lithium cation exist as a cone conformation, the trianions appear to exist as a partial cone conformation, and the dianions appear to disproportionate to the mono and trianions. The conformational stability decreases in the order of $Li^+$ oxyanion > $Na^+$ oxyanion > $K^+$ oxyanion.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.6
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• pp.653-662
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• 2017

Copper(II) acetate spectrophotometry method (CASM) was used for the rapid and convenient determination of cation exchange capacity (CEC) in soils. This method is composed of a single-step exchange reaction that adsorbs copper and is measured through spectrophotometry. The CEC of 16 Korean soils were measured using 1M ammonium acetate method (AAM) and the CASM. The CEC values determined by CASM and AAM were not significantly different, and were highly correlated ($r=0.966^{**}$). Due to the convenience, cost effectiveness, and time saving analysis of CASM, this method is recommended for most soil laboratories to measure CEC in Korean soils. However, CASM may not be applicable for soils that have a much higher CEC (greater than $20cmol_c\;kg^{-1}$).

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.3
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• pp.112-115
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• 2021

Herein, a correlation between B-site cation order and spin-phonon coupling in La₂NiMnO₆ double perovskite has been investigated. Raman spectra of La₂NiMnO₆ double perovskite annealed at 950 and 1400℃ have been measured in the 140-598 K range. A substantial softening of the phonon modes has been observed below the Curie temperature, which emphasized the presence of the spin-phonon coupling in the system. The spin-phonon coupling was found to be stronger in relatively more ordered La₂NiMnO₆ double perovskite. Thus, the magnitude of spin-phonon coupling was influenced by the Ni/Mn cation order.

• Journal of the Mineralogical Society of Korea
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• v.15 no.4
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• pp.329-344
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• 2002

Mineralogical and chemical characterization of some domestic bentonites, such as quantitative XRD analysis, chemical leaching experiments, pH and CEC determinations, were done without any separation procedures to understand their relationships among mineral composition, characteristics, and cation exchange properties. XRD quantification results based on Rietveld method reveal that the bentonites contain totally more than 25 wt% of impurities, such as zeolites, opal-CT, and feldspars, in addition to montmorillonite ranging 30～75 wt%. Cation exchange properties of the zeolitic bentonites are deeply affected by the content of zeolites identified as clinoptilolite-heulandite series. Clinoptilolite is common in the silicic bentonites with lighter color. and occurs closely in association with opal-CT. Ca is mostly the dominant exchangeable cation, but some zeolitic bentonites have K as a major exchangeable cation, The values of cation exchange capacity (CEC) determined by Methylene Blue method are comparatively low and have roughly a linear relationship with the montmorillonite content of the bentonite, though the correlated data tend to be rather dispersed. Compared to this, the CEC determined by Ammonium Acetate method, i.e.‘Total CEC’, has much higher values (50～115 meq/100 g). The differences between those CEC values are much greater in zeolitic bentonites, which obviously indicates the CEC increase affected by zeolite. Other impurities such as opal-CT and feldspars seem to affect insignificantly on the CEC of bentonites. When dispersed in distilled water, the pH of bentonites roughly tends to increase up to 9.3 with increasing the alkali abundance, especially Na, in exchangeable cation composition. However, some bentonites exhibit lower pH (5～6) so as to regard as ‘acid clay’. This may be due to the presence of $H^{＋}$ in part as an exchangeable cation in the layer site of montmorillonite. All the works of this study ultimately suggest that an assesment of domestic bentonites in grade and quality should be accomplished through the quantitative XRD analysis and the ‘Total CEC’measurement.

• Journal of the Korean Institute of Gas
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• v.9 no.4 s.29
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• pp.17-25
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• 2005

The dealuminated and alkali/alkaline-earth metal exchanged Y-zeolites were prepared as a catalyst. Elemental compositions and structures of the prepared catalysts were analyzed by the various spectroscopic techniques such as inductively coupled plasma-atomic emission spectroscopy(ICP-AES), X-ray fluorescence(XRF) and X-ray diffraction(XRD), and the desorption behaviors of adsorbed species on the catalyst surfaces were investigated via NO-TPD experiment. Comparing with the composition of the starting material of NaY zeolite, the magnitudes of Si/Al ratio in catalytic materials were increased after dealumination. The Si/Al ratio of catalytic materials after dealumination followed by Cs and Ba cation exchange were additionally decreased. Dealumination to catalysts induced a destruction of basic frame due to a detachment of aluminum, which results in reducing framework structure, while increasing non-framework structure. This phenomenon becomes more serious with increasing time of steam treatment and even more significant for the cation exchanged catalysts. In NO-TPD experiments, the desorption peaks of NO which indicates an activity point of catalysts shifted to the low temperature region after dealumination and cation exchange. The desorption peaks of the NO-TPD profiles taken after steam treatment also shifted to the low temperature region as the steam treatment time increased. In dealuminated and cation exchanged Y-zeolites, the catalytic activities were more influenced by exchanged cation and the formation of non-framework structure.

• Journal of the Korean Chemical Society
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• v.46 no.6
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• pp.515-522
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• 2002

Solid beta-dicalcium silicate hydrate $(\beta-C_2SH)$ synthesized under hydrothermal conditions at $240^{\circ}C$ and Ca/Si=2 molar ratio shows cation exchange properties towards divalent metal cations such as Fe, Cu, Zn, Cd, or Pb. The ability of metal cation uptake by the solid was found to be in the order: $Fe^{2+}$〉$Cu^{2+}$〉$Zn^{2+}$〉$Cd^{2+}$ = $Pb^{2+}$. Cesium selectivity of the solid was demonstrated in the presence of univalent cation such as $Li^+$, $Na^+$ and $K^+$ and divalent cations such as $Ca^{2+}$, $Mg^{2+}$ and $Ba^{2+}$, which are one hundred times more concentrated than the $Cs^+$. The uptake of $Cs^+$ is maximum in the presence of $Mg^{2+}$ whereas it is minimum in the presence of $K^+$. The different affinities of ${\beta}-C_2SH$ towards divalent metal cations can be used for the separation of those ions. Due to its selectivity for cesium it can be used in partitioning of radioactive Cs+ from nuclear wastes containing numerous cations. The mechanism of the metal cation exchange and cesium selectivity reactions by the solid is studied.