• Economic and Environmental Geology
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• v.11 no.3
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• pp.89-98
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• 1978

Mineralogy, beneficiation, and processes of titanium ores are reviewed from petrographic viewpoints. The most important titanium minerals are ilmenite ($FeTiO_3$) and rutile ($TiO_2$). Ilmenite will play major role :for raw material, because rutile are rapidly diminishing. Thus, there is a need to develope a successful process for producing high grade Ti02 from ilmenite. Commercial, as well as R and D processes to treat more abundant ilmenite ores fall in three general classess: 1. Iron in ilmenite is partially or completely reduced and separated either physically or chemically. 2. Iron is reduced to ferrous state and chemically leached away from the titanium. 3. Ore is treated to make chlorides either selectively or with subsequent separation and purification of $TiC_4$. Routes and efficiencies of these process technologies are primarily influenced by the particular ore deposit to be mined and secondly by environmental considerations. One deposit parameters which influence ilmenite process technologies are: 1. Complexity of microtextures of ilmenite intergrown with Fe-oxide minerals. 2. Composition of concentrates; ilmenites contain minor amounts of substituted Mg, Mn, and V. These elements plus iron and gangue minerals can cause difficulties to complete reactions, substantial acid consumption, difficulties of removing waste solids, and waste disposal problems. Major contributions to be made by petrologists for process optimization are: characterization and interpretation of compositional and physical changes of raw materials and solids derived from process streams. These informations can play significant role in selecting and improving process steps for titania production.

• Applied Microscopy
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• v.32 no.3
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• pp.265-273
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• 2002

The purpose of this study was to observe the influences of the water fluoride concentration on the growth changes, the histologic characteristics of osteoblast in the tibia of growing newborn rats by using electron microscopy and on the composition changes of bone matrix in those by using energy dispersive x-ray system (EDX). The water fluoride concentration was respectively 0 ppm (contrast group), 100 ppm (100 ppm group), 200 ppm (200 ppm group) and 300 ppm (300 ppm group). The results of the investigation by using electron microscopy were as followed. In contrast group, the traditional cuboidal osteoblasts were observed. In 100 ppm group, several reversal line, the newly formed osteoid by the strongly activated osteoblast and the well developed rough endoplasmic reticulum, mitochondria in cytoplasm of osteoblast were observed. Also, many secretory vesicle around cell membrane were observed and some fused with cell membrane released secretory granule out of cell. In 200 ppm group, the depressed osteoblasts were observed, mitochondria in cytoplasm were expanded and cristae shape in mitochondria were destroyed. Also, the ribosome at the surface of rough endoplasmic reticulum were not observed. In 300 ppm group, the adjacent osteoblasts with endosteum were irregularly arranged, the cell membrane were destroyed and organelles were flowed out of cell. On the other hand, the results of the investigation by using energy dispersive x-ray system were as followed. P and Ca concentrations in 100 ppm group were increased more than those in contrast group. But, in 200 and 300 ppm group were not increased more than those in 100 ppm group. Therefore, the activities of the osteoblasts were increased, the bone matrix were actively synthesized by the supplied water fluoride. But, the osteoblasts were destroyed, inhibited by the higher water fluoride concentration.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.7
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• pp.854-862
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• 2016

In summer 2010, we measured the concentration of dissolved oxygen (DO) and nutrients in the water collected at the bottom of Cheonsu Bay, off the west coast of Korea. We also measured nutrient fluxes across the sediment-water interface by deploying a fully-automated benthic lander, which collected time-series water samples inside a benthic chamber. We confirmed on-going hypoxia in the northern parts of the bay where polluted lake water was discharged. DO content in the water at the bottom was 2 mg/l, compared to 5 mg/l at the mouth of the bay in the south. Nutrient concentrations showed a trend that was opposite to that of DO. The variation of N/P ratios implies phosphate desorption and a release of nutrients caused by hypoxia. The organic carbon oxidation rate and oxygen consumption rate in the northern parts of the bay were about twice as fast as those at the mouth of the bay. Benthic fluxes of nutrients in the northern part of the bay were 4 to 6 times higher than those at the mouth. Our results imply that it is important to understand the role of hypoxia events to make an accurate estimation of material fluxes across the sediment-water interface.

• The Journal of Natural Sciences
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• v.8 no.2
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• pp.119-127
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• 1996

The effect of sodium hydroxide treatment on some physicochemical properties of zeolite mordenite mineral was studied with chemical analyses, powder X-ray diffraction, thermal analyses, infrared analysis, measurement of carbon dioxide adsorption and gas chromatography. Mordenite mineral from tuffaceous rocks in Yeongil and Wolsung area was used as a starting material and treated with 0.1-5N NaOH aqueous solution at about $95^{\circ}C$ in the water bath for three hours.At the concentration of sodium hydroxide below 0.5N, all chemical compositions in the tuff were virtually insoluble and the mordenite structure did not change. At the concentration above 1N, the chemical compositions such as silica, alumina, etc., were dissolved. The dissolution ratio of silica was lager than that of alumina, and the ratio of silica to alumina in the tuff decreased sharply in the concentration range of 2 to 3N. Intensity of X-ray diffraction peak of mordenite (202) plane and the adsorbed amount of carbon dioxide also decreased with the increasing concentration of sodium hydroxide above 1N. These decreases corresponded to the degree of mordenite structure collapsed.The separation of gas chromatography of nitrogen, oxygen and carbon monoxide was not affected by the sodium hydroxide treatment, but elution peaks of methane and krypton tended to be broadened and their retention time was shortened. The elution peaks of both methane and krypton tended to be overlapped with those of nitrogen and oxygen.

• Polymer(Korea)
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• v.32 no.1
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• pp.13-18
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• 2008

For the evaluation of brominated flame retardants included in polymeric electronic devices, we investigated the extraction methods and solvent systems for four different types of polymers of PC (polycarbonate), PP (polyropylene), PET (poly(ethylene terephthalate)) and PBT (poly(butylene terephthalate)) using different solvent systems of hexane/acetone, THF, toluene, and THF/toluene. In order to compare the extraction efficiency of different methods and solvent systems, the deca-BDE (decabromo diphenyl ether) flame retardant was included in PC, PP, PET and PBT systems and subsequently extracted by soxhlet, ultrasonic, accelerated solvent, microwave and supercritical fluid extraction methods. The amount of the extracted flame retardant was monitored to evaluate the extraction efficiency. The ultrasonic extraction method was found not to be acceptable as an extraction method for the polymer systems mainly due to a low salvation efficiency of the organic solvents. Soxhlet, accelerated solvent and microwave extraction methods exhibited over 80% of extraction efficiency for toluene. The supercritical fluid extraction method, which has been used as an extraction method for flame retardants in polymers, showed the extraction efficiencies of ca. 100% for PC and PP in the optimal extraction conditions of $60^{\circ}C$ and 120 bar.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.3
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• pp.466-472
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• 1997

Peptides separated from fish paste washing liquid of an Alaska pollak (Theragria chalcogramma) were purified and characterized. The fish paste washing liquid (supernatant) was separated by centrifugation of fish paste homogenate. The fish paste washing liquid of $0.5\%$ concentration was hydrolyzed for 24 hour at $50^{\circ}C$ by immobilized protease in bioreactor and decomposing liquid of protein having $50\%$ decomposing rate (OPA method) was obtained. The crude peptide fractions were obtained from this liquid by Dowex 50w $(H^+)$ column chromatograpy. Purified peptides (SP-fraction peptides) were fractionated by using SP-Sepadex C-25 $(H^+)$ column chromatography. Molecular weights and amino acid compositions of these peptides were estimated by Sephadex G-50 column chromatography and HPLC, respectively. when the washed peptides was eluated with $0.6\~0.9\%\;and\;1.2\~2.0\%$ of NaCl, peptides composed of weakly basic amino acids and strongly basic amino acid were respectively eluted. Molecular weights of each peptide fractions showed the broad distribution from 1,000 Da to 3,000 Da in the order of SP-4>SP-3>SP-2>SP-1. Peptides contained a large quantity of glycine, arginine, glutamic acid, and alanine in the washed peptide and its SP-tractions, respectively.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.789-792
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• 2008

Blast furnace slag doesn't have self-hydraulicity and it needs stimulants such as alkali to hydrate. Therefore using recycled aggregates erupted calcium hydroxides and blast furnace slag acquiring alkali stimulate could make a complementarily use of a recycling architectural material possible. In this study, we have discussed about characters of blast furnace slag and recycled aggregate firstly, and make recycled aggregate mortar and concrete using blast furnace slag for the experiment. The experiment is about mortar and concrete using recycled aggregate as a substitutional material of blast furnace slag. In this experiment, I replace blast furnace slag and aggregate with recycled aggregate. Conclusions through the test results analysis are as follows. And then, we added field experiment using concrete with composited materials.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.5
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• pp.218-224
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• 2015

Recently, removing methods of red tide has been attempted by filtering the organisms using the ceramic porous bodies. However, the marine biofouling could be developed on the surfaces of porous ceramic body after use for more than one month, and it might decrease the function of the specimen. In this paper, a method of inhibiting marine biofouling by changing the physical properties or surface-modification of ceramic porous body was studied. After experiment with six different ceramic porous bodies, it was found that the specimen of lower porosity and water absorption showed the least amount of biofouling. In addition, by increasing the surface roughness with silica particles bonded to the surface of specimen, the amount of biofouling caused by large marine life such as barnacle and mussel could be decreased. On the other hand, when the surface of specimen was coated and fused by glass powder, the amount of biofouling was rather increased. This might be due to eluted inorganic ions from the glass which can promote the growth of the microorganism. In conclusion, the environmental-friendly methods to reduce the amount of marine biofouling, such as controlling the physical properties and the surface roughness of the porous ceramics, can be possible without the use of dangerous substances. So it is expected for the results obtained to be applicable to a marine structure.

• Food Science and Preservation
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• v.23 no.7
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• pp.939-944
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• 2016

The aim of this study was to establish an optimum blanching condition for outer cabbage leaves to increase utilization of the byproduct. Outer leaves of Kimchi cabbages were cut to size ($4{\times}4cm$) and blanched at 80, 90, $100^{\circ}C$ for 1, 3, and 5 min. Subsequently, weight loss, pH, total bacteria, coliform and texture properties were investigated. Sensory evaluation of a ready-to-cook soup prepared from blanched outer leaves was investigated to determine whether the quality of the blanched outer leaves was acceptable. Both weight loss and pH of outer leaves of Kimchi cabbage were increased by blanching. Compared to raw samples, total bacterial counts decreased and coliform bacteria were not detected. The hardness of raw leaf samples was $1.5kg{\cdot}force$ (N). Sample hardness was 18.7~21.7% lower after blanching for 3 min and 34.8~36.7% after blanching for 5 min. Sensory evaluation of outer leaves blanched at $100^{\circ}C$ for 5 min revealed significant differences from the other treatments (p<0.05). In addition, sensory evaluation scores for texture and appearance of outer leaves blanched at $100^{\circ}C$ for 3 min were higher than those for commercially available products. The results of this study indicate that blanching can be effective for developing a food product from the outer leaves of Kimchi cabbage.

• Korean Journal of Medicinal Crop Science
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• v.16 no.4
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• pp.211-217
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• 2008

To find up using of more efficient white ginseng, white ginseng was dried on various temperature (70, 80, 90,100, 110, 120, 130 and $140^{\circ}C$) with far-infrared drier and analyzed the composition of ginsenoside, carbohydrate, organic acid content and color. The type of ginseng shape was sliced and dried main and fine root, separately. As heating temperature increased, total ginsenoside content increased on main root, its content was the highest at $130^{\circ}C$, while decreased on fine root. Soluble carbohydrate content was the highest at $70^{\circ}C$ both on main and fine root. Increase of Re, Rc and Rb2 content was increased more high at $130^{\circ}C$, especially. But on fine root, content of Rg1, Rg3, Rf and Rb3 was increased and Re, Rc,Rb1 and Rb2 were decreased by the increased of temperature. As heating temperature increased, lightness of both main and fine root were decreased. Redness and yellowness of both main and fine root was increased to $120^{\circ}C$ and $100^{\circ}C$, respectively and decreased over this temperature.