• Conservation Science in Museum
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• v.4
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• pp.23-32
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• 2003

As the kettle excavated from a site in Hwangnam-dong, Gyeongju was presumed to have been used as a melting crucible in a glass production workplace, we decided to prove its usage by scientific analysis. First, we performed conservation treatment to find the original status of the kettle, and then SEM-EDS and XRD analysis of the five corrosions created on the surface of the kettle. The fragment of the spout, which played a crucial role for the kettle to be considered as a melting crucible, was discovered during the conservation treatment. So the mouth rim of the kettle was restored to perfection. When we observed the microstructure of the metal sample, it was proved to be cast iron gradually cooled without heat treatment. In the corrosion products, the main components were Fe and O and other components such as P, Si, Ca, and S were found. The main compounds were quartz, vivianite, goetheite, akaganite, lepidocrocite, hematite, etc. Although these components were used as raw materials for making glass, these were found not in the melting status but mere raw materials. This can be an evidence to show these site where the kettle was excavated had been a glass production workplace. However, it is not sure that the kettle was used as a melting crucible. Moreover, if we consider the organic mold and sand clay accumulated in the well site when the kettle was excavated at first, we can see this as a formative factor of the corrosions of the kettle. Therefore, we concluded that the kettle is a typical cast iron and was not used as a melting crucible of glass.

• Journal of Conservation Science
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• v.34 no.1
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• pp.39-50
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• 2018

This study replicated traditional smelting methods to produce iron blooms from sand iron. The metallurgical properties of the slag and the iron blooms were analyzed. The sand iron materials used in the smelting experiments, which were based on ancient documents, were collected from Gyeong-Ju and Pohang. Analysis by WD-XRF and XRD showed that Gyeong-Ju's sand iron contains a high-titanium, with magnetite, and Pohang's sand iron contains a low-titanium, which magnetite and ilmenite were mixed. Analysis of the slag with XRD, and the micro-structure with metal microscopes and SEM-EDS, confirmed that the major compounds in the slag of the Gyeong-Ju's sand iron were fayalite and $w\ddot{u}stite$, and those in the slag of the Pohang's sand iron were titanomagnetite and fayalite. The differences in the main constituents were confirmed according to the Ti quantity. Finally, we observed the microstructures of the iron blooms. In the case of the iron bloom produced from Gyeong-Ju's sand iron, the outside was found to be dominantly a pearlite of eutectoid steel, while the inside was a hypo-eutectoid steel where ferrite and pearlite were mixed together. While, the major component of the iron bloom produced from Pohang's sand iron was ferrite, which is almost like pure iron. However, there were many impurities inside the iron blooms. Therefore, this experiment confirmed that making ironware required a process that involved removing internal impurities, refining, and welding. It will be an important data to identify the characteristics of iron by-products and the site through traditional iron-making experiments under various conditions.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2010.03a
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• pp.40-40
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• 2010

Studies on attractive color changing property of dye chromophore and fluorophore have been greatly enjoyed in the related industrial and research fields such as optoelectronics, chemosensor, biosensor and so on. The optical property based on D-$\Pi$-A intramolecular charge transfer (ICT) system of chromophore molecules can be utilized as suitable sensing probes for checking media polarity and determining colorimetric chemosensing effect, especially heavy metal detection. These finding are obtained by absorption and emission properties. In this work, donor-acceptor D-$\Pi$-A type fluorescent dyes were designed and synthesized with the corresponding donor and acceptor groups. The selected donor moieties might be provided prominent amorphous properties which are very useful in designing and synthesizing functional polymers and in fabricating devices. Another reasons to choose are commercial availabilities in high purity and low price. Donor-bridge-acceptor (D-A) type dyes can produce impressive optical-physical properties, yielding them potentially suitable for applications in the synthesis of small functional organic molecules. Small organic functional molecules have unique advantages, such as better solubility, amorphous character, and represent an area of research which needs to be explored and developed. Currently, their applications in metalorganic compounds is rapidly expanding and becoming widespread in self-assembly processes, photoluminescence applications, chiral organocatalysts, and ingrafts with nanomaterials. Colloidal nanoparticles have received great attentions in recent years. The photophysical properties of nanoparticles, particularly in terms of brightness, photostability, emission color purity and broad adsorption range, are very attractive functions in many applications. To our knowledge background, colloidal nanoparticles have been enjoyed their applications in bio-probe research fields. This research interest can be raised by the advantages of the materials such as high photoluminescence quantum yields, sharp emission band, long-term photostability and broad excitation spectra. In recent, the uses of nanoparticles being embedded in a polymer matrix and binded on polymer surface have been explored and their properties such as photo-activation and strong photoluminescence have been proposed. The prepared chromophores and nanoparticles were investigated with absorption and emission properties, solvatochromic behaviors, pH induced color switching effects, chemosensing effects and HOMO/LUMO energy potentials with computer simulation. In addition, synthesized fluorophore dyes and particles were applied onto PE/Aramid fiber fluorescing colorations. And the related details were then discussed.

• Applied Biological Chemistry
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• v.43 no.3
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• pp.163-168
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• 2000

To remove phosphate accumulated in the soil and water, Acinetobacter lwoffi PO8 possessing a high ability to accumulate phosphate was isolated from a active sludge. Bacterium was cultured in the liquid medium containing $150\;{\mu}g/mL$ of phosphate at $30^{\circ}C$ in different culture conditions to examine intracellular phosphate uptake. The initial pH in the range of $7.5{\sim}8.5$ was effective on the growth and phosphate uptake of the strain. Glycerol and arabinose used as a carbon sources showed 93 and 91% the phsphate uptake, respectively. Among the nitrogen sources, ammonium salt such as $NH_4NO_3$ and $(NH_4)_2SO_4$ was effectively utilized on the phosphate uptake compared with amino compounds. The rate of phosphate uptake of $NH_4NO_3$, and $(NH_4)_2SO_4$, was 95 and 96%, respectively The growth and Phosphate uptake ability in the strain were significantly promoted when metal ions were added in the medium; $Co^{2+}$, however, was not utilized by the strain. The capacity of phosphate uptake was enhanced to $10{\sim}20%$ when arginine, methionine, or lysine was added. Using $^{32}P$ to examine the uptake Pattern of intracellular phosphate, experiment result showed that polyphosphate was largely found in the fraction of intracellular inorganic phosphate of Acinetobacter lwoffi PO8.

• Bulletin of the Korean Chemical Society
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• v.15 no.11
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• pp.961-966
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• 1994

Oligomerization of phenylacetylene is catalyzed by $Rh(ClO_4)(CO)(PPh_3)_2$ (Rh-1), $[Rh(CO)(PPh_3)_3]ClO_4$ (Rh-2), $[Rh(COD)L_2]ClO_4 (L_2=(PPh_3)_2$, Rh-3; $(PPh_3)(PhCN)$, Rh-4; $(PhCN)_2$, Rh-5), $[Rh(C_3H_5)(Cl)(CO)(SbPh_3)_2]ClO_4$ (Rh-6), $[Ir(COD)L_2]ClO_4 (L_2=(PPh_3)_2$, $Ir-1; (PPh_3)(PhCN)$, $Ir-2; (PhCN)_2$, Ir-3; (AsPh_3)(PhCN)$, $Ir-4; Ph_2PCH_2CH_2PPh_2$, Ir-5; COD, Ir-6 and 2,2'-dipyridyl, Ir-7), $Ir(ClO_4)(CO)(PPh_3)_2$, $Ir-8, [Ir(PhCN)(CO)(PPh_3)_2]ClO_4$, Ir-9 to produce dimerization products, 1,3-diphenylbut-1-yn-3-ene, 1, (E)-1,4-diphenylbut-1-yn-3-ene, 2 and (Z)-1,4-diphenylbut-1-yn-3-ene, 3, and cyclotrimerization products, 1,3,5-triphenylbenzene, 4 and 1,2,4-triphenylbenzene, 5. Product distribution of the oligomers varies depending on various factors such as the nature of catalysts, reaction temperature, counter anions and excess ligand present in the reaction mixtures. Increasing reaction temperature in general increases the yield of the cyclotrimerization products. Exclusive production of dimer 1 and trimer 4 can be obtained with Ir-1 at 0 $^{\circ}$C and with Ir-2 in the presence of excess PhCN (or $CH_3CN$) at 50 $^{\circ}$C, respectively. Dimer 2 (up to 81%) and trimer 5 (up to 98%) are selectively produced with Rh-1 at 50 and 100 $^{\circ}$C respectively. Production of 3 is selectively increased up to 85% by using $PF_6$- salt of $[Ir(COD)(PPh_3)_2]$+ at 25 $^{\circ}$C. Addition of $CH_3I$ to Rh-1 produces $CH_3PPh_3^+I-$ and increases the rate of oligomerization(disappearance of phenylacetylene). Among the metal compounds investigated in this study, Ir-1 catalyzes most rapidly the oligomerization where the catalytically active species seems to contain lr(PPh3)2 moiety. The stoichiometric reaction of phenylacetylene wth Ir-9 at 25 $^{\circ}$C quantitatively produces hydridophenyl-ethynyl iridium(III) complex, $[lr(H)(C{\equiv}CPh)(PhCN)(CO)(PPh_3)_2]ClO_4$ (Ir-11), which seems to be an intermediate for the oligomerization.

• Bulletin of the Korean Chemical Society
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• v.16 no.11
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• pp.1067-1074
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• 1995

Reaction of arachno-S2B7H8- with either THF or 1,2-dimethoxyethane upon refluxing condition results in the formation of the previously known compound hypho-S2B7H10-. Protonation of hypho-S2B7H10- with HCl/Et2O generates hypho-2,5-S2B7H11 in good yield. This hypho-S2B7H10- anion has been employed to generate a series of new nido-, arachno-, and hypho-metalladithiaborane clusters. Reaction of the anion with Cp(CO)2FeCl results in direct metal insertion and the formation of a complex containing the general formula (η5-C5H5)FeS2B7H8. Spectroscopic studies of nido-6-CpFe-7,9-S2B7H8 Ⅰ demonstrated that compound Ⅰ was shown to have an nido-type cage geometry derived from an octadecahedron missing one vertex, with the iron atom occupying the three-coordinate 6-position in the cage and the two sulfurs occupying positions on the open face of the cage. Reaction of hypho-S2B7H10- with CoCl2/Li+[C5H5]- gave the previously known complex arachno-7-CpCo-6,8-S2B6H8 Ⅱ. Also, the reaction of the anion with [Cp*RhCl2]2 gave the complex arachno-7-Cp*Rh-6,8-S2B6H8 Ⅲ, the structure of which was shown to be that of complex Ⅱ. The similarity of the NMR spectra of Ⅱ and Ⅲ suggest that Ⅲ adopts cage structure similar to that previously confirmed for Ⅱ. A series of 9-vertex hypho clusters in which the sulfur atoms are bridged by different species isoelectronic with a BH3 unit, such as HMn(CO)4 or SiR2 have been prepared. Compounds Ⅳ,Ⅴ and Ⅵ are each 2n+4 skeletal electron systems and would be expected according to skeletal electron counting theory to adopt hypho-type polyhedral structures derived from an icosahedron missing three vertices. The complex hypho-1-(CO)4Mn-2,5-S2B6H9 Ⅳ was obtained by the reaction of the anion with (CO)5MnBr and has been shown from spectroscopic data to consist of a (CO)4Mn fragment bound to the two sulfur atoms S2 and S5 of hypho-S2B7H10-. Also, similar hypho-type complexes hypho-1-R2Si-2,5-S2B6H8 (R=CH3 Ⅴ, R=C6H5 Ⅵ) have been prepared from the reaction of hypho-S2B7H10- with R2SiHCl.

• Korean Journal of Microbiology
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• v.55 no.1
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• pp.69-73
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• 2019

During screening of microbes for compounds having cosmetic benefits, we isolated Marinobacter salarius HL2708#2 from lava seawater on Jeju Island, Republic of Korea. The complete genome sequence was determined. Strain HL27080#2 features a circular chromosome of 4,304,603 bp with 57.21% G+C content and a 244,163 bp plasmid with 53.14% G+C. There were 4,180 protein coding sequences identified, along with 49 transfer RNA and 18 ribosomal RNA noncoding genes. The genome harbored genes for the utilization of alcohol, maltose/starch, and monosaccharide as sole carbon sources. Genes responsible for halophilic characteristics and heavy metal resistance could be annotated, as well as aromatic and alkane hydrocarbons. Contrary to the prior report that M. salarius is negative for nitrate and nitrite reduction, nitrate/nitrite reductase along with nitrate/nitrate transporters and nitronate monooxygenase were evident, suggesting that strain HL2708#2 may be able to denitrify extracellular nitroalkenes to ammonia.

• Journal of the Korean GEO-environmental Society
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• v.12 no.7
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• pp.23-29
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• 2011

The oxidation slag has been widely used in civil engineering project, whereas the reduced slag from electric furnace has yet to be applied. Consequently in order to find out the recycling method in civil engineering field, the mineral compositions of the reduced slag were analyzed and some tests on water quality were performed to estimate the potential release of toxic compounds. Slag-soil mixtures of 0, 10, 20 and 30%(dry weight) soil were prepared in lysimeter columns and the effluents were collected with the period of one, two and four week options in closed system, respectively. The result from qualitative and quantitative analysis using X-ray Diffraction(XRD) and X-ray Fluorescence(XRF) indicates that the main mineral of the reduced slag is $Ca_2(SiO_4)$, a kind of calcium silicate. Also, the leaching medium analyzed by Inductively Coupled Plasma Optical Emission Spectroscopy(ICP-OES) showed that main heavy metals such as Al, Fe and Mn are included in the reduced slag due to the effect of steel production process. It can be seen that the leachate does not violate the regulation guide line of waste material of heavy metal. Also the pH levels were increased from pH 6.9 for 0% soil to pH 10 for 30% soil. However the influence on leachate circulation period of one through four weeks was negligible.

• Korean Journal of Poultry Science
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• v.49 no.4
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• pp.221-228
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• 2022

Major egg white proteins and their hydrolysates serve as functional food ingredients that have certain metal-chelating properties. Employing egg white proteins and their hydrolysates to scavenge dietary oxalates is anticipated to have beneficial effect in the prevention of kidney stones. The objective of this study was to determine the biogenic oxalate-chelating activity of ovalbumin, ovomucin, and ovotransferrin and their hydrolysates. To prepare oxalate extracts, 30 mL of 0.25 N HCl was added to separately to 0.5 g of dried spinach and starfruit powders followed by boiling for 15 min, and after cooling, the addition of a further 20 mL of 0.25 N HCl. Having prepared these extracts, ovalbumin, ovomucin, and ovotransferrin and their hydrolysates were separately mixed with oxalate extracts and incubated at 3℃ for 24 h. Following centrifugation, supernatants were analyzed by HPLC using a reverse-phase C18 column coupled with a diode array detector. We found that all assessed proteins and their hydrolysates showed biogenic oxalate-chelating activity against the oxalates of spinach. In contrast, however, only ovalbumin, ovalbumin-hydrolysate, and ovomucin showed chelating activity (57.10%±8.84%, 85.44%±5.30%, 73.20%±4.13%, respectively) against the oxalates of starfruit (P<0.05). Overall, hydrolyzed ovalbumin was identified as the most effective chelator of the oxalates both spinach and starfruit. In this study, we thus established that the assessed egg white proteins and their hydrolysates have oxalate-chelating activity in vitro, thereby indicating that these compounds have potential utility as nutraceuticals for the chelation of dietary oxalate. However, further research will be necessary to verify their oxalate-chelating activities against different fruits and vegetables and under specific in vivo conditions and against purified oxalate.

• Clean Technology
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• v.28 no.2
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• pp.174-181
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• 2022

Biomass is a sustainable alternative resource for production of liquid fuels and organic compounds that are currently produced from fossil fuels including petroleum, natural gas, and coal. Because the use of fossil fuels can increase the production of greenhouse gases, the use of carbon-neutral biomass can contribute to the reduction of global warming. Although biological and chemical processes have been proposed to produce petroleum-replacing chemicals and fuels from biomass feedstocks, it is difficult to replace completely fossil fuels because of the high oxygen content of biomass. Production of petroleum-like fuels and chemicals from biomass requires the removal of oxygen atoms or conversion of the oxygen functionalities present in biomass derivatives, which can be achieved by catalytic hydrodeoxygenation. Hydrodeoxygenation has been used to convert raw biomass-derived materials, such as biomass pyrolysis oils and lignocellulose-derived chemicals and lipids, into deoxygenated fuels and chemicals. Multifunctional catalysts composed of noble metals and transition metals supported on high surface area metal oxides and carbons, usually selected as supports of heterogeneous catalysts, have been used as efficient hydrodeoxygenation catalysts. In this review, the catalysts proposed in the literature are surveyed and hydrodeoxygenation reaction systems using these catalysts are discussed. Based on the hydrodeoxygenation methods reported in the literature, an insight for feasible hydrodeoxygenation process development is also presented.