• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1063-1067
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• 1997

This study was performed to assess the levels of the trace elements(Fe, Cu, Zn, Cr, Co, Mn, Pb, and Cd) in salt-fermented fish products from some areas of the west coast in Korea. Seven samples were Shrimp(Seawoo-jeot), Clam(Jogai-jeot), Oyster(Orikul-jeot), big eyed horring(Bendeng-ie jeot), Mysis(Gonjeng-ie jeot), Hwangandali(Hwangsegi-jeot), and Squid, Han Chi(Han chi-jeot). They were ashed with ternary solution. After ashing the samples, the amount of trace elements in the samples were measured by ICP. The moisture content of the 7 samples before freezing dry were 68.36, 71.52, 81.19, 62.27, 71.30, 64.27, and 66.74%, respectively. Jogai-jeot and Gonjeng-ie jeot contained the most amount of moisture among the samples. Fe contents were 66.46, 309.10, 27.03, 23.01, 132.45, 35.75, and 9.72ppm, respectively. Jogai-jeot contained the most amount of Fe among the samples. Cu contents were 4.60, 4.36, 3.75, 2.21, 10.36, 2.71, and 58.15ppm, respectively. Hanchi-jeot contained the most amount of Cu among the samples. Zn contents were 16.02, 75.06, 37.43, 28.43, 132.45, 35.75, and 9.72ppm, respectively. Gonjeng-ie jeot contained the most amount of Zn among the samples. Cr contents were 0.80, 1.61, 0.84, 0.96, 1.12, 0.96, and 0.59ppm, respectively. Jogai-jeot contained the most amount of Cr among the samples. Co contents were 0.13, 0.54, 0.31, 0.46, 0.50, 0.63, and 0.35ppm, respectively. Hwangsegi-jeot contained the most amount of Co among the samples. Mn contents were 7.30, 10.69, 14.87, 4.12, 8.03, 2.94 and 1.54ppm, respectively. Origkul-jeot contained the most amount of Mn among the samples. Pb contents were 1.80, 4.30, 2.53, 4.61, 3.08, 5.04, and 2.74ppm, respectively. Hwangsegi-jeot contained the most amount of Pb among the samples. Cd contents were 0.005, 0.03, 0.06, 0.005, 0.01, 0.00, and 0.10ppm, respectively. Hanchi-jeot contained the most amount of Cd among the samples. This study is limited within 7 samples caught and producted from the some areas of the west coast in Korea. Therefore, I hope there will be broader experiments concerned with this study to make clear not only nutritional aspect(the contents of Fe, Cu, Zn, Cr, Co, and Mn) but also toxicological aspect(the contents of Pb and Cd).

• Journal of the Korean Chemical Society
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• v.47 no.4
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• pp.315-324
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• 2003

In this study, a new method is presented to produce stable hydrophobic metal alloy nanocluster in chloroform solution including surfactant NaAOT(sodium bis(2-ethylhexyl)-sulfosuccinate) via the chemical reduction of metal salt $(HAuCl_4,\AgNO_3,\Cu(NO_3)_2)$ by sodium borohydride. For the alloy nanocluster, several samples were prepared by changing the molar ratio of Au/Cu, Au/Ag alloy nanocluster, 3:1, 1:1, 1:3. The alloy nanoclusters were characterized by UV-Visible spectrophotometer, TEM(Transmission Electron Microscope), and XPS(X-ray Photoelectron Spectrometer). With the change of the mole ratio of the alloy component, the wavelengths of the surface plasmon absorption shift linearly from 520 nm of the pure Au nanocluster to 570 nm of the pure Cu nanocluster for Au/Cu alloy nanoclusters and from 405 nm to 520 nm for Au/Ag alloy nanoclusters. The chemical shifts of the Au4f, Ag3d, Cu2p XPS peaks were observed with changing the molar ratio of the alloy element. The alloy nanoclusters in chloroform solution were made uniformly in size and colloidally stable for long periods of time. These results indicate that the method here is a very effective method for synthesizing hydrophobic alloy nanoclusters with uniform or nearly uniform particle size distribution.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.2
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• pp.105-112
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• 2005

The electrolytic reduction of uranium oxide in a LiCl-Li$_{2}$O molten salt system has been studied in a 10 g U$_{3}$O$_{8}$ /batch-scale experimental apparatus with an integrated cathode assembly at 650$^{\circ}C$. The integrated cathode assembly consists of an electric conductor, the uranium oxide to be reduced and the membrane for loading the uranium oxide. From the cyclic voltammograms for the LiCl-3 wt$\%$ Li$_{2}$O system and the U$_{3}$O$_{8}$-LiCl-3 wt$\%$ Li$_{2}$O system according to the materials of the membrane in the cathode assembly, the mechanisms of the predominant reduction reactions in the electrolytic reactor cell were to be understood; direct and indirect electrolytic reduction of uranium oxide. Direct and indirect electrolytic reductions have been performed with the integrated cathode assembly. Using the 325-mesh stainless steel screen the uranium oxide failed to be reduced to uranium metal by a direct and indirect electrolytic reduction because of a low current efficiency and with the porous magnesia membrane the uranium oxide was reduced successfully to uranium metal by an indirect electrolytic reduction because of a high current efficiency.

• Applied Chemistry for Engineering
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• v.18 no.5
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• pp.467-474
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• 2007

The palladium and gold nanoparticles containing PAN-based active carbon fiber (ACF) with a high specific surface area were prepared. Using the BET, TEM, FE-SEM, and XPS, their specific surface area and pore volume, pore structure, and the change in surface oxygen groups with time were analyzed and $SO_2$ adsorption performances were investigated. Because of the impregnating process, the micropore volume was mostly decreased from 95.5% to 30.5~43.7% compared with the total pore volume. And the change in surface oxygen groups with time was higher for the metal salt than the nanoparticles. Also, $SO_2$ breakthrough time of PAN-ACFs impregnated with Au nanoparticles and metal salts did not change compared with that of the non-impregnated PAN-ACF. But the PAN-ACF impregnated with Pd nanoparticles (100 ppm) showed good $SO_2$ adsorption performance as the breakthrough time of 880 sec. These results indicated that the $SO_2$ adsorption performance depended on the change in surface oxygen groups with time and the moderate impregnation of Pd nanoparticles on the PAN-ACF caused the increase in the $SO_2$ adsorption performance by a catalytic action.

• Journal of the Korean Wood Science and Technology
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• v.37 no.3
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• pp.245-254
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• 2009

As a substitute for CCA, which is inhibited due to its environmental pollution and human harmfulness, and CuAz and ACQ with a high cost, okara-based wood preservatives were formulated with okara hydrolyzates using copper sulfate and/or borax as a metal salt. The efficacy of the preservatives and X-ray microanalysis of wood specimens treated with the preservatives were examined to confirm the potential of the okara-based wood preservatives. Most of the preservatives showed excellent decay resistance against brown-rot fungi, Postia placenta and Gloeophyllum trabeum. The efficacy was improved when the acid concentration and temperature used for the hydrolysis of okara increased. In addition, when borax was added into copper sulfate/okara hydrolyzates preservative formulations, any decay was not found in the specimens. From the microscopic observation of the specimens treated with okara-based wood preservatives, it seems that okara is contributed to the fixing of metal salts in wood blocks. Therefore, it is speculated that okara-based wood preservatives can effectively protect wood against fungal attack as CuAz, and that the preservatives are sufficient to use as an alternative wood preservative of CCA, ACQ and CuAz.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.588-588
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• 2013

Nanoscale noble-metals have attracted enormous attention from researchers in various fields of study because of their unusual optical properties as well as novel chemical properties. They have possible uses in diverse applications such as devices, transistors, optoelectronics, information storages, and energy converters. It is well-known that nanoparticles of noble-metals such as silver and gold show strong absorption bands in the visible region due to their surface-plasmon oscillation modes of conductive electrons. Silver nanocubes stand out from various types of Silver nanostructures (e.g., spheres, rods, bars, belts, and wires) due to their superior performance in a range of applications involvinglocalized surface plasmon resonance, surface-enhanced Raman scattering, and biosensing. In addition, extensive efforts have been devoted to the investigation of Gold-based nanocomposites to achieve high catalytic performances and utilization efficiencies. Furthermore, as the catalytic reactivity of Silver nanostructures depends highly on their morphology, hollow Gold nanoparticles having void interiors may offer additional catalytic advantages due to their increased surface areas. Especially, hollow nanospheres possess structurally tunable features such as shell thickness, interior cavity size, and chemical composition, leading to relatively high surface areas, low densities, and reduced costs compared with their solid counterparts. Thus, hollow-structured noblemetal nanoparticles can be applied to nanometer-sized chemical reactors, efficient catalysts, energy-storage media, and small containers to encapsulate multi-functional active materials. Silver nanocubes dispersed in water have been transformed into Ag@Au nanoboxes, which show highly enhanced catalytic properties, by adding $HAuCl_4$. By using this concept, $SiO_2$-coated Ag@Au nanoboxes have been synthesized via galvanic replacement of $SiO_2$-coated Ag nanocubes. They have lower catalytic ability but more stability than Ag@Au nanoboxes do. Thus, they could be recycled. $SiO_2$-coated Ag@Au nanoboxes have been found to catalyze the degradation of 4-nitrophenol efficiently in the presence of $NaBH_4$. By changing the amount of the added noble metal salt to control the molar ratio Au to Ag, we could tune the catalytic properties of the nanostructures in the reduction of the dyes. The catalytic ability of $SiO_2$-coated Ag@Au nanoboxes has been found to be much more efficient than $SiO_2$-coated Ag nanocubes. Catalytic performances were affected noteworthily by the metals, sizes, and shapes of noble-metal nanostructures.

• Journal of Soil and Groundwater Environment
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• v.7 no.1
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• pp.53-62
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• 2002

The physical and chemical properties of cover soils of 10 waste landfill sites in Kyonggi-Do area, where social circumstances at present forces to consider the reuse of landfill, were investigated to provide the informations of soil environment which are necessary to establish the appropriate ecological restoration plan of waste landfills. The pH and electrical conductivity of soils were higher in landfills sites than in reference sites (area around landfill sites), indicating the salt accumulation in surface soil. However, total-N and organic matter contents were lower in landfills sites than in reference sites. In landfill sites, the total-N and plant available-P contents were less than 0.15% and 20mg/kg, respectively. Exchangeable cations (K, Ca, Mg and Na) and heavy metal (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) contents varied between the landfill sites, but were higher in landfills sites than in reference sites. The major exchangeable cation of soil was Ca. Heavy metal contents were much lower than the critical concentration which phytotoxicity is considered to be possible and the standard for agricultural land of Korean Soil Environmental Preservation Act. Therefore, the proper soil management plan to increase the soil fertility is recommended for the ecological restoration of landfill using natural or artificial vegetation.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1442-1445
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• 2000

This study was carried out to investigate the contents of minerals and heavy metals in the sea salts of Korean products and imported products. NaCl was major component, which ranged from $80.31{\sim}89.84%$ for Korean products and from $91.59{\sim}97.66%$ for imported products. Minerals and heavy metals of Korean products and imported products were analyzed with ICP-AES and AAS, respectively. Mineral contents of K and Mg in Korean products were relatively higher than those in imported ones, but no significant differences were found for heavy metals between them.

• Journal of the Korean Magnetics Society
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• v.8 no.6
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• pp.335-340
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• 1998

Colossal magnetoresistance $La_{0.67}Ca_{0.33}Mn_{0.99}^{57}Fe_{0.01}O_3$ material has been produced by a metal-salt routed sol-gel process method. Magnetic properties of $La_{0.67}Ca_{0.33}Mn_{0.99}^{57}Fe_{0.01}O_3$ have been studied with x-ray diffraction, Rutherford back-scattering spectroscopy(RBS), vibrating sample magnetometer, and Mossbauer spectroscopy. Crystalline $La_{0.67}Ca_{0.33}Mn_{0.99}^{57}Fe_{0.01}O_3$ was perovskite cubic structure with a lattice parameter $a_0=3.868$\AA$$. And there was no appreciable change in the value of the lattice parameter when a small amount (x=0.01) of iron was added. However, Mossbauer and VSM data indicate the Curie temperature of the $La_{0.67}Ca_{0.33}Mn_{0.99}^{57}Fe_{0.01}O_3$ decreased from 282 to 270 k and also the saturation magnetization from 84 to 81 emu/g at 77 K. Mossbauer spectra of $La_{0.67}Ca_{0.33}Mn_{0.99}^{57}Fe_{0.01}O_3$ have been taken at various temperatures ranging form 4.2 K to room temperature. Analysis of $^{57}Fe$ Mossbauer data in terms of the local configurations of Mn atoms has permitted the influence of the magnetic hyperfine interactions to be monitored. The isomer shifts show that the charge state of all Fe ions are ferric. The magnetoresistance of $La_{0.67}Ca_{0.33}Mn_{0.99}^{57}Fe_{0.01}O_3$ was about 33 % at semiconductor-metal transition temperature $T_{SC-M}=250K$.

• Membrane Journal
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• v.33 no.4
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• pp.149-157
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• 2023

Covalent organic frameworks (COFs) have shown promise in various applications, including molecular separation, dye separation, gas separation, filtration, and desalination. Integrating COFs into membranes enhances permeability, selectivity, and stability, improving separation processes. Combining COFs with single-walled carbon nanotubes (SWCNT) creates nanocomposite membranes with high permeability and stability, ideal for dye separation. Incorporating COFs into polyamide (PA) membranes improves permeability and selectivity through a synthetic interfacial strategy. Three-dimensional COF fillers in mixed-matrix membranes (MMMs) enhance CO₂/CH₄ separation, making them suitable for biogas upgrading. All-nanoporous composite (ANC) membranes, which combine COFs and metal-organic framework (MOF) membranes, overcome permeance-selectivity trade-offs, significantly improving gas permeance. Computational simulations using hypothetical COFs (hypoCOFs) demonstrate superior CO₂ selectivity and working capacity relevant for CO₂ separation and H₂ purification. COFs integrated into thin-film composite (TFC) and polysulfonamide (PSA) membranes enhance rejection performance for organic contaminants, salt contaminants, and heavy metal ions, improving separation capabilities. TpPa-SO₃H/PAN covalent organic framework membranes (COFMs) exhibited superior desalination performance compared to traditional polyamide membranes by utilizing charged groups to enable efficient desalination through electrostatic repulsion, suggesting their potential for ionic and molecular separations. These findings highlight COFs' potential in membrane technology for enhanced separation processes by improving permeability, selectivity, and stability. In this review, COF applied for the separation process is discussed.