• Journal of Life Science
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• v.25 no.9
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• pp.1027-1035
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• 2015

A strain GP32 which produces a highly viscous extracellular polysaccharide was conducted with soil samples and identified as Pseudomonas species. The culture flask conditions for the production of extracellular polysaccharide by Pseudomonas sp. GP32 were investigated. The most suitable carbon and nitrogen source for extracellular polysaccharide production were galactose and (NH₄)₂SO₄. The optimum carbon/nitrogen ratio for the production of extracellular polysaccharide was around 50. The optimum pH and temperature for extracellular polysaccharide production was 7.5 and 32℃, respectively. In batch fermentation using a jar fermentor, the highest extracellular polysaccharide content (15.7 g/l) was obtained after 70 hr of cultivation. The extracellular polysaccharide produced by Pseudomonas sp. GP32 (designated Biopol32) was purified by ethanol precipitation, cetylpyridinium chloride (CPC) precipitation, and gel permeation chromatography. Biopol32, which has an estimated molecular weight of over 3×10⁷ datons, is a novel polysaccharide derived from sugar components consisting of galactose, glucose, gulcouronic acid and galactouronic acid in an approximate molar ratio of 1.85 : 3.24 : 1.00 : 1.42. The solution of Biopol32 showed non-Newtonian characteristics. The viscosity of Biopol32 exhibited appeared to be higher at all concentration compared to that of zooglan from Zoogloea ramigera. An analysis of the flocculating efficiency of Biopol32 in industry wastewater (food, textile, and paper wastewater) revealed chemical oxygen demand (COD) reduction rates 58.4-67.3% and suspended solid (SS) removal rates 82.6-91.3%. Based on these results, Biopol32 is a possible candidate for industrial applications such as wastewater treatment.

• Journal of Food Hygiene and Safety
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• v.29 no.3
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• pp.234-240
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• 2014

Fluxapyroxad is classified as carboxamide fungicide that inhibits succinate dehydrogenase in complex II of mitochondrial respiratory chain, which results in inhibition of mycelial growth within the fungus target species. This study was carried out to assure the safety of fluxapyroxad residues in agricultural products by developing an official analytical method. A new, reliable analytical method was developed and validated using High Performance liquid Chromatograph-UV/visible detector (HPLC-UVD) for the determination of fluxapyroxad residues. The fluxapyroxad residues in samples were extracted with acetonitrile, partitioned with dichloromethane, and then purified with silica solid phase extraction (SPE) cartridge. Correlation coefficient($R^2$) of fluxapyroxad standard solution was 0.9999. The method was validated using apple, pear, peanut, pepper, hulled rice, potato, and soybean spiked with fluxapyroxad at 0.05 and 0.5 mg/kg. Average recoveries were 80.6~114.0% with relative standard deviation less than 10%, and limit of detection (LOD) and limit of quantification (LOQ) were 0.01 and 0.05 mg/kg, respectively. All validation parameters were followed with Codex guideline (CAC/GL 40). LC-MS (Liquid Chromatograph-Mass Spectrometer) was also applied to confirm the analytical method. Base on these results, this method was found to be appropriate fluxapyroxad residue determination and can be used as the official method of analysis.

• The Journal of the Petrological Society of Korea
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• v.11 no.3_4
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• pp.259-270
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• 2002

A small granodiorite-quartz monzonitic stock containing sericitic and propylitic alteration assemblages hosts a Cu-W breccia-pipe deposit in the southeastern Cyeongsang basin. The mineralized breccia-pipe contains angular to subangular brecciated fragments of granitic rocks showing clast-supported textures. An assemblage of quartz, tourmalines, sulfide minerals (mainly chalcopyrite, arsenopyrite and pyrrhotite) and calcite was precipitated as a hydrothermal cement between the brecciated fragments. A tourmaline aureole surrounds the breccia pipe. Extensive tourmalinization of the granitic rocks near and within the pipe and no tourmalinization in the sedimentary and volcanic rocks. The tourmalines are marked by Fe-rich, black charcoal-like schorl (80 mol% schorl relative) nearer the schorl-dravite solid solution. The chemical changes in the hydrothermal fluid are reflected by variations in compositional Boning from cores to rims. They generally contain cores with low values of Fe/(Fe+Mg) and high values of Na/(Na+ca) relative to rims. This is because of an increase Fe and Ca contents toward rims. The main trend of these variations is a combination of the exchange vectors Ca(Fe, Mg) $(NaAl)_{- }$ $_1$ and $Fe^{3}^{+}$ $Al_{[-10]}$ $_1$ It is thought that boiling causes the loss of $H_2$ into the vapor phase resulting in the oxidation of Fe in the aqueous phase. pH of the melt would be one of important controlling factors for the tourmaline stability. The tourmalines could be precipitated when the system evolved to the acidic hydrothermal regime as most hydrothermal brines and acidic gases exsolved from the magma. The Ilgwang tourmaline crystallization is products of hypogene orthomagmatic hydrothermal processes that were strongly pipe-controlled.

• Journal of the Korean earth science society
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• v.21 no.1
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• pp.59-66
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• 2000

In Kyeongsang basin, there were very dynamic magmatic activities, resulting to form volcanic and plutonic rocks. A plutonic recycle appeared in this region. Presumption of the pressure for hornblende-bearing granitic rock among the plutonic rocks, can support important informations for the emplacement depth of Cretaceous Bulgugsa granites in Kyeongsang basin. $Al^T$(Al total) contents of hornblende is related to the pressure, oxygen fugacity, and compositions of other minerals having the solid solution. So we apply the $Al^T$ content of hornblende to several empirical and experimental geobarometer systems to presume the pressure and to determine the emplacement depth of Cretaceous Bulgugsa granites in Kyeongsang basin from the inferred pressure. With the result that we applied the $Al^T$ contents of hornblende to the various geobarometers, there was a positive relationship between the pressure and $Al^T$. The minimum pressure value ranges from 0.73 to 1.70kbar in Kyeongju and the maximum value from 2.02 to 3.16kbar in Kimhae. And then the tectonic setting in Kyeongsang basin has no relation to the emplacement depth of Cretaceous granites and means variations with the movement of vertical component in each area. As we suppose that the density of earth's crust is $2.8g/cm^3$, the average values of the emplacement depth ranges in each area range from 2.6 to 11.4km. These data confirm the previous idea about the emplacement depth of Cretaceous granites in Kyeongsang basin, and these geobarometers using the $Al^T$ contents of hornblende is available though they have much limits. Therefore Cretaceous Bulgugsa granites in Kyeongsang basin was the shallow depth intrusive rut and the exposed granites was the shallow depth crust.

• Journal of Plant Biotechnology
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• v.32 no.1
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• pp.37-44
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• 2005

Microspores were isolated from pepper (Capsicum annuum L.) anthers by using a micro-blender and cultured in modified NLN medium at $25^{\circ}C$. The influence of pretreatment period at $32^{\circ}C$, adding the 2-hydroxynicotinic acid to a pretreatment medium, and co-pretreatment anthers with microscopes on the induction of embryo were examined. Globular and torpedo embryos were observed from 3 weeks after culture. Embryo development was not synchronized within culture. After 4 weeks in culture, in addition to globular and torpedo embryos, cotyledonary embryos were observed. Normal cotylodonary embryos developed into plantlets when transferred to a solid hormone free B5 medium containing $2\%$ sucrose. Embryo yields were significantly higher after 1- and 2-day pretreatment at $32^{\circ}C$. However the development of embryo ceased at the globular or heart stage. In contrast, embryo yields were lower after 3- to 6-day pretreatment at $32^{\circ}C$ and embryo developed at the cotyledonary stage. After adding the 2-hydroxynicotinic acid to anther pretreatment solution, embryo yields were slightly increased. However most embryos occurred were at the globular or heart stage. Co-pretreatment of microspores with anthers was deleterious for embryo induction and development. AS far as we know, this is the first report of success in obtaining high frequency of embryogenesis and plantlets formation from isolated microspores of pepper. Although the culture conditions have to be optimized further, this promising microspore culture system can be used for genetic transformation, selection for dominant and recessive traits as well as for the production of homozygous doubled haploid plants.

• Journal of Plant Biotechnology
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• v.45 no.2
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• pp.110-116
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• 2018

This study was conducted to develop a simple, rapid, and reliable method for in vitro propagation of disease-free and true-to-type clones from sucker explants of thornless blackberry (Rubus fruticosus L. ${\times}$ R. parvifolius L.). To induce multiple shoots, the sucker explants were sterilized in 1% NaOCl solution, and then were aseptically cultured on the full and 1/2 MS solid medium supplemented with BAP (0.1, 0.5, 1.0, 2.0 mg/L). After six weeks of culture, the highest frequency (85.4%) of shoot formation from sucker explants was obtained on the full-strength MS medium with 1.0 mg/L BAP. Node explants obtained from multiple shoots were cultured on the various media of full- or half-strength of AD, B5, MS, SH, QL, WPM media, respectively. After 30 days of culture, plant growth was good on the half-AD, half-QL medium. After 90 days of culture, plant growth was good on the full MS and full SH medium. The survival rate of the plantlets after transfer to plastic pots containing soil mixture (sand: soil: vermiculite was 1:1:1, vol.) in the greenhouse was 98%. The results indicate that a multiple-shoot procedure can be applied for an efficient mass propagation of Rubus fruticosus L. ${\times}$ R. parvifolius L.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.3
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• pp.135-151
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• 1977

The present paper summerizes the studies on clay mineralogical characteristics of Korean soil, relationship between potassium and clay minerals, potassium release pattern of clay minerals and utilization of clay minerals for soil conditioner and fertilizers, which have been carried out in this laboratory. 1. The red yellow podzolic soil is mostly abundant in the upland of Korea and mainly consists of halloysite and weathered intermediates of mica such as illite and vermiculite. 2. With regard to soil parent material, kaolin mineral occurs abundant in soils derived from granite and granite gneiss. Mica is dominant in basaltic soil. The main clay mineral of the soil, originated from the Tertiary, is found montmorillonite and the volcanic soil of Jeju Island has plenty of allophane as its main clay mineral. 3. It is confirmed that the soil fertility depends on the composition of clay minerals. The red yellow podzolic soil, containing lot of kaolin, shows low productivity while the montmorillonite soil has higher productivity. 4. The release rate of solid phase potassium (micas and fixed potassium) follows the 1st order reaction equation in the equilibrium solution of $IN-NH_4OAc$. The potassium release constant is positively correlated with the mica content of the clay but negatively correlated with the content of $14.5{\AA}$ minerals. On the other hand, the potassium release constant has very high correlation with the ratio(Kex/Kt) of exchangeable potassium(Kex) to total potassium(Kt). 5. It is also found that Kex/Kt has rather high correlation with the content of mica and $14.5{\AA}$ minerals existed in the clay as well as the mica content of the soil.

• KSBB Journal
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• v.24 no.1
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• pp.1-8
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• 2009

In the past decade, we have observed rapid advances in the development of biochips in many fields including medical and environmental monitoring. Biochip experiments involve immobilizing a ligand on a solid substrate surface, and monitoring its interaction with an analyte in a sample solution. Metal nanoparticles can display extinction bands on their surfaces. These charge density oscillations are simply known as the localized surface plasmon resonance (LSPR). The high sensitivity of LSPR has been utilized to design biochips for the label-free detection of biomolecular interactions with various ligands. LSPR-based optical biochips and biosensors are easy to fabricate, and the apparatus cost for the evaluation of optical characteristics is lower than that for the conventional surface plasmon resonance apparatus. Furthermore, the operation procedure has become more convenient as it does not require labeling procedure. In this paper, we review the recent advances in LSPR research and also describe the LSPR-based optical biosensor constructed with a core-shell dielectric nanoparticle biochip for its application to label-free biomolecular detections such as antigen-antibody interaction.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.3
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• pp.19-27
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• 2003

Surface finishes of PCB laminates are important in the solder joint reliability of flip chip package because the types and thicknesses of intermetallic compound(IMC), and compositions and hardness of solders are affected by them. In this study, effects of surface finishes of PCB on the low cycle fatigue resistance of Sn-based lead-free solders; Sn-3.5Ag, Sn-3.5Ag-XCu(X=0.75, 1.5), Sn-3.5Ag-XBi(X=2.5, 7.5) and Sn-0.7Cu were investigated for the Cu and Au/Ni surface finish treatments. Displacement controlled room temperature lap shear fatigue tests showed that fatigue resistance of Sn-3.5Ag-XCu(X=0.75, 1.5), Sn-3.5Ag and Sn-0.7Cu alloys were more or less the same each other but much better than that of Bi containing alloys regardless of the surface finish layer used. In general, solder joints on the Au/Ni finish showed better fatigue resistance than those on the Cu finish. Cross-sectional fractography revealed microcracks nucleation inside of the interfacial IMC near the solder mask edge, more frequently on the Cu than the Au/Ni surface finish. Macro cracks followed the solder/IMC interface in the Bi containing alloys, while they propagated in the solder matrix in other alloys. It was ascribed to the Bi segregation at the solder/IMC interface and the solid solution hardening effect of Bi in the $\beta-Sn$ matrix.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.1
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• pp.41-51
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• 2020

The purpose of this study was to investigate the possibility of eco-friendly/efficient recovery of valuable resources, such as Au from mine tailings, which are environmental pollutants in the Mongolian mine sector. For this purpose, this study selected 4 place of mine tailings of the Mongolian mines sector and carried out mineralogy evaluation of the valuable resources in the tailings. In this study, flotation was performed to separate and concentrate valuable resources in the tailings. Microwave nitric acid leaching was used to leach the valuable resources contained in the sample and to improve the Au grade. Chloride leaching attempted to leach Au from the leaching residues. XRD analysis of the tailings samples showed that most of the samples consisted of silicate minerals. As a result of confirming the content of the element through XRF analysis, the SiO₂ content was very high, the Fe₂O₃ content was 2.32-4.23%, and the content of PbO, CuO and ZnO components were all within 2%. As a result of flotation for the tailings samples, the recovery of Au was the highest in Bayanairag sample (95.38%). As a result of microwave nitric solution experiment on Au concentrate sample obtained by flotation, the content of Au in the microwave nitrate leaching residue increased by 12.15% from 192.72 g/ton to 216.14g/ton in Khamo sample, the highest increase was 57.58% in Bayanairag sample. TCLP tests on tailings generated after flotation showed dissolution characteristics within EPA. Chloride leaching test was performed to recover Au from solid residues. The leaching rate was 87.43-89.35% within 10 minutes. For Khamo sample, 100% Au was leached after 60 minutes of leaching time. Therefore, in order to process the tailings continuously generated in Mongolia, applying the same process as the present study is expected to effectively recover the valuable resources contained in the tailings.