• Bulletin of the Korean Chemical Society
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• v.15 no.9
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• pp.782-785
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• 1994

The dissociation kinetics of linear polyaminopolycarboxylate complexes of lanthanide ions (L$n^{3+}: Ce^{3+},\;Eu^{3+}\;and\;Yb^{3+}$) has been studied in an aqueous solution of 0.10 M (NaCl$O_4$) at 25.0${\pm}0.1^{\circ}C$ using Cu(II) ions as a scavenger. The dissociation rates of acid-catalyzed pathway decrease in the order Ln(EPDTA$)^- > Ln(DPOT)^- > In(TMDTA)^- > Ln(MPDTA)^- > Ln(EDTA)^- > Ln(PDTA)^- > Ln(DCTA)^-$ according to the present and literature data. An increase in the N-Ln-N chelate ring from 5 to 6 and substitution of two methyl groups, one ethyl and hydroxyl group on a chelate ring carbon of these ligands leads to a decrease in kinetic stabilities of the complexes. The substitution of one methyl group and cyclohexyl ring on a ring carbon, however, results in a significant increase in the kinetic stability of the resulting $Ln^{3+}$ complexes. Individual reaction steps taking place for each system, with different copper, acetate buffer concentration and pH dependence, are also discussed.

• Bulletin of the Korean Chemical Society
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• v.19 no.2
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• pp.197-201
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• 1998

The complex formation from Cu(Ⅱ) ion and 1,3-bis(tris(hydroxymethyl)methylamino)propane (bistrispropane) in aqueous solution has been studied potentiometrically and spectrophotometrically. Bistrispropane (btp) coordinates to Cu(Ⅱ) as multidentate. In the btp (L) complex CuL2+, two of the hydroxyl oxygen atoms as well as the amine nitrogens of the ligand are coordinated. In neutral and weakly acidic media, one of the coordinated hydroxyl groups is deprotonated. In basic media, an additional hydroxyl group undergoes deprotonation. The equilibrium constants for the formation of CuL2+, CuLH-1+, and CuLH-2 have been determined. The nature of the coordinate bonds has been deduced from the potentiometric data and the spectra of these complexes.

• Bulletin of the Korean Chemical Society
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• v.16 no.3
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• pp.243-248
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• 1995

Single crystal EPR spectra of K12[As2W18O66Cu3(H2O)2]${\cdot}$11H2O exhibit an orientation-dependent fine structure of an S = 3/2 system which is accounted for by the exchange and magnetic dipole interactions among the three Cu2+ ions. The hyperfine structure and the lines from the S = 1/2 manifolds have not been observed. The isotropic exchange parameters determined from the magnetic susceptibility data at 5-300 K are J1 = J2 =-7.8 cm-1. The magnitude of J values suggests that the unpaired electrons on three Cu2+ ions interact through a sequence of six bonds involving two tungsten atoms and three oxygen atoms. The Cu-Cu distance, 4.37 $\AA$, determined from the EPR spectra is considerably smaller than the value from the X-ray crystal structure determination, 4.76 $\pm$ 0.03 $\AA$, indicating that the point-dipole model underestimates the dipolar interaction.

• Journal of the Korean Chemical Society
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• v.61 no.1
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• pp.29-33
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• 2017

Formation of Au particles in nonstoichiometric $Cu_{2-x}{^I}Cu{_2}^{II}O_{3-{\delta}}$ ($x{\approx}0.20$; ${\delta}{\approx}0.10$) oxide from aniline + hydrochloric acid mixtures and chloroauric acid in the ratios 30 : 1; 60 : 1; 90 : 1 (S1-S3) by volume and 0.01 mol of copper acetate, $Cu(OCOCH_3)_2.H_2O$, in each case is performed by sol-gel growth. Powder x-ray diffraction (XRD) results show Au particles are dispersed in tetragonal nonstoichiometric dicopper (I) dicopper (II) oxides, $Cu_{2-x}{^I}Cu{_2}^{II}O_{3-{\delta}}$ ($x{\approx}0.20$; ${\delta}{\approx}0.10$). Average crystallite sizes of Au particles determined using Scherrer equation are found to be in the approximate ranges ${\sim}85-140{\AA}$, ${\sim}85-150{\AA}$ and ${\sim}80-150{\AA}$ in S1-S3, respectively which indicate the formation of Au nano-micro size particles in $Cu_{2-x}{^I}Cu{_2}^{II}O_{3-{\delta}}$ ($x{\approx}0.20$; ${\delta}{\approx}0.10$) oxides. Hysteresis behaviour at 300 K having low loop areas and magnetic susceptibility values ${\sim}5.835{\times}10^{-6}-9.889{\times}10^{-6}emu/gG$ in S1-S3 show weakly ferromagnetic nature of the samples. Broad and isotropic electron paramagnetic resonance (EPR) lineshapes of S1-S4 at 300, 77 and 8 K having $g_{iso}$-values ${\sim}2.053{\pm}0.008-2.304{\pm}0.008$ show rapid spin-lattice relaxation process in magnetic $Cu^{2+}$ ($3d^9$) sites as well as delocalized electrons in Au ($6s^1$) nano-micro size particles in the $Cu_{2-x}{^I}Cu{_2}^{II}O_{3-{\delta}}$ ($x{\approx}0.20$; ${\delta}{\approx}0.10$) oxides. Broad and weak UV-Vis diffuse reflectance optical absorption band ~725 nm is assigned to $^2B_{1g}{\rightarrow}^2A_{1g}$ transitions, and the weak band ~470 nm is due to $^2B_{1g}{\rightarrow}^2E_g$ transitions from the ground state $^2B_{1g}$(${\mid}d_{x^2-y^2}$>) of $Cu^{2+}$ ($3d^9$) ions in octahedral coordination having tetragonal distortion.

• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1439-1444
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• 2006

A $Cu^{2+}$ ion-selective membrane microelectrode has been fabricated from poly vinyl chloride (PVC) matrix membrane containing a new symmetrical hexadentate Schiff,s base 2-{1-(E)-2-((Z)-2-{(E)-2-[(Z)-1-(2-hydroxyphenyl)ethylidene]hydrazono}-1-methylpropylidene)hydrazono]ethyl}phenol (HDNOS) as a neutral carrier, Potassium tetrakis(4-chlorophenyl) borate (KTpClPB) as an anionic excluder and o-nitrophenyloctyl ether (NPOE) as a plasticizing solvent mediator. The microelectrode displays linear potential response in the concentration range of $1.0\;{\times}\;10^{-5}-1.0\;{\times}\;10^{-11}$ M of $Cu^{2+}$. The microelectrode exhibits a nice Nernstian slope of 25.9 ${\pm}$ 0.3 mV $decade^{-1}$ in the pH range of 3.1-8.1. The sensor has a relatively short response time in whole concentration ranges ($\sim$5 s). The detection limit of proposed sensor is $5.0\;{\times}\;10^{-12}$ M (320 pg/L), and it can be used over a period of eight weeks. The practical utility of the sensor has been demonstrated by using it as an indicator electrode in the potentiometric titration of $Cu^{2+}$ with EDTA. The proposed membrane electrode was used for the direct determining of $Cu^{2+}$ content in black and red pepper, and in waste water samples.

• Environmental Mutagens and Carcinogens
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• v.11 no.2
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• pp.99-106
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• 1991

Facilitated transport of lipophilic benzo(a)pyrene into human fibroblast cells by low density lipoproteins (LDL) was examined. Amounts of [3H]-labeled B(a)P taken up by the Hep 2 fibroblast was increased 3 folds by the addition of LDL (100ng of protein/105 cells) in the media. However, we have found that the facilitated B(a)P transport into cells were diminished by the addition of LDL of which the apoproteins were modified by copper(II) ion-catalyzed oxidation in 10nM copper sulfate. The results of the present study suggest that lipophilic compounds are taken up via adsorptive endocytosis which is mediated by interactions between apoproteins on LDL.

• Current Photovoltaic Research
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• v.1 no.2
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• pp.109-114
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• 2013

$Cu_2ZnSnS_4$ (CZTS) nanoparticles were synthesized by a solvothermal method using copper (II) acetate, zinc acetate, tin chloride, and sulfur in diethylenetriamine solvent. Binary sulfide particles such as CuS, ZnS, SnS, and $SnS_2$ were obtained at $180^{\circ}C$; single-phase CZTS nanoparticles were obtained at $280^{\circ}C$. CZTS nanoparticles with spherical shape and grain size of 40 to 60 nm were obtained at $280^{\circ}C$. In the middle of 180 and $280^{\circ}C$, CZTS and ZnS phases were found. The time variation of reaction at $280^{\circ}C$ revealed that an amorphous state formed first instead of binary phases and then the amorphous phase was converted to crystalline CZTS state; it is different reaction path way from conventional solid-state reaction path of which binary phases react to form CZTS. CZTS films deposited and annealed from single-phase nanoparticles showed porous microstructure and poor adhesion. This indicates that a combination of CZTS and other flux phase is necessary to have a dense film for device fabrication.

• Journal of Microbiology and Biotechnology
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• v.23 no.7
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• pp.942-952
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• 2013

Monoliths are functional porous materials with a three-dimensional continuous interconnected pore structure in a single piece. A monolith with uniform shape based on poly(${\gamma}$-glutamic acid) (PGA) has been prepared via a thermally induced phase separation technique using a mixture of dimethyl sulfoxide, water, and ethanol as solvent. The morphology of the obtained monolith was observed by scanning electron microscopy and the surface area of the monolith was evaluated by the Brunauer Emmett Teller method. The effects of fabrication parameters such as the concentration and molecular mass of PGA and the solvent composition have been systematically investigated. The PGA monolith was cross-linked with hexamethylene diisocyanate to produce the water-insoluble monolith. The addition of sodium chloride to the phase separation solvent affected the properties of the cross-linked monolith. The swelling ratio of the cross-linked monolith toward aqueous solutions depended on the buffer pH as well as the monolith fabrication condition. Copper(II) ion was efficiently adsorbed on the cross-linked PGA monolith, and the obtained copper-immobilized monolith showed strong antibacterial activity for Escherichia coli. By combination of the characteristic properties of PGA (e.g., high biocompatibility and biodegradability) and the unique features of monoliths (e.g., through-pore structure, large surface area, and high porosity with small pore size), the PGA monolith possesses large potentials for various industrial applications in the biomedical, environmental, analytical, and separation fields.

• Economic and Environmental Geology
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• v.36 no.2
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• pp.75-87
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• 2003

The Haman-Gunbuk mineralized area is located within the Cretaceous Gyeongsang Basin along the southeastern part of the Korean peninsula. Major ore minerals, magnetite, scheelite, molybdenite and chalcopyrite, together with base-metal sulfides and minor sulfosalts, occur in fissure-filling tourmaline, quartz and carbonates veins contained within Cretaceous sedimentary and volcanic rocks anu/or granodiorite (118{\pm}$3.0 Ma). The ore and gangue mineral paragenesis can be divided into three distinct stages: Stage 1, tourmaline+quartz+Fe-Cu ore mineralization; Stage II, quartz+sulfides+sulfosalts+carbonates; Stage 111, barren calcite. Earliest fluids are recorded in stage I and early por-tions of stage II veins as hypersaline (35~70 equiv. wt.% NaCl+KCl) and vapor-rich inclusions which homogenize from ~30$0^{\circ}C$ to $\geq$50$0^{\circ}C$. The high-salinity fluids are complex chloride brines with significant concentrations of sodium, potassium, iron, copper, and sulfur, though sulfide minerals are not associated with the early mineral assemblage produced by this fluid. Later solutions circulated through newly formed fractures and reopened veins, and are recorded as lower-salinity(less than ~20 equiv. wt.% NaCl) fluid inclusions which homogenize primarily from ~200 to 40$0^{\circ}C$. The oxygen and hydrogen isotopic compositions of fluid in the Haman-Gunbuk hydrothermal system represents a progressive shift from magmatic-hydrothermal dominance during early mineralization stage toward meteoric-hydrothermal dominance during late mineralization stage. The earliest hydrothermal fiuids to circu-late within the granodiorite stock localiring the ore body at Haman-Gunbuk could have exsolved from the crystal-lizing magma and unmixed into hypersaline liquid and $H_2O$-NaCl vapor. As these magmatic fluids moved throughfractures, tourmaline and early Fe, W, Mo, Cu ore mineralization occurred without concomitant deposition of othersulfides and sulfosalts. Later solutions of dominantly meteoric origin progressively formed hypogene copper and base-metal sulfides, and sulfosalt mineralization.

• Korean Journal of Poultry Science
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• v.16 no.1
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• pp.17-22
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• 1989

In order to dull heat sensitivity of egg albumen, metal ions (aluminium, ferric, ferrous, copper) were added and functional properties or egg albumen were determined before and after heat treatment at $60^{\circ}C$ for 5 minutes. Effect of pH on heat sensitivity of aluminium salt added egg albumen was also determined. Addition of metal ions increased turbidity of egg albumen before and after the heat treatment. Changes of the turbidity were minimized by addition of aluminium salt. The foaming power was markedly increased by addition of ferric salt before the heat treatment and increased by addition of aluminium, ferric and copper salt after the heat treatment. Before the heat treatment the foam was stable by addition of ferric and ferrous salt but after the heat treatment it was stable by addition of aluminium and ferric salt. The turbidity and foaming property of the egg albumen with aluminium salt were not largely changed after the heat treatment at pH range 7 to 8.5. Over pH 9 the turbidity and foaming power were not decreased, but the foam stability was increased before and after the heat treatment. Salmonella typhimurium ATCC 14028 (10$^{6}$ cells/$m\ell$) inoculated in egg albumen at pH range 7 to 8.5 was destructed by the heat treatment.