• Economic and Environmental Geology
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• v.40 no.5
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• pp.587-604
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• 2007

In order to investigate the vertical variations and speciations of trace elements, and their correlations in Hoidong reservoir, sediment cores (21-41 cm below surface) and interstitial water samples were collected from five sampling locations. The total average concentrations of trace metals in sediment core samples were $232{\pm}30.8mg/kg$ for Zn, $119{\pm}272mg/kg$ for Cu, $58.4{\pm}4.1mg/kg$ for Pb, $15.7{\pm}3.3mg/kg$ for Ni and $1.6{\pm}0.3mg/kg$ for Cd. The total concentrations of trace metals in core sediments generally decreased toward the center of the Hoidong reservoir. The total concentrations of Mn, Pb and Zn decreased with depth for all the sample locations, while Cu and Fe concentrations increased. The trace metal concentrations of interstitial water sample were in the order of Fe>Mn>Cu>Zn, but Cd, Ni and Pb were not detected. The concentrations of Zn, Cu, Fe and Mn in the interstitial water samples showed a tendency of increasing toward the bottom of the core, suggesting a possible upward diffusion. This migration of trace metals may lead to their transfer to the sediment-water interface. These trace elements would be subsequently fixed onto amorphous Fe and Mn-oxides and carbonates in the topmost layer of sediment. Based on the $K_D$ values, the relative mobilities of the studied metals were in the order of Mn>Cu>Zn>Fe. Geochemical partitioning confirmed that surface enrichment by trace metals mainly resulted from a progressive increase of the concentrations in the fractions II and III. Copper, Fe, Mn and Zn concentrations of interstitial water were closely correlated with their exchangeable fractions of sediments.

• Mineral and Industry
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• v.26
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• pp.13-21
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• 2013

This study is carried out experiments on various factors for improving the grade of low grade scheelite by Knelson concentrator prior to the main beneficiation process. Even though there are several gravity separators such as Jig, Spirals and etc. for rougher concentrate, the KC3 Knelson Concentrator was adopted to get better separation efficiency and beneficiating effects for pre-concentration of the low grade scheelite ore. The feed samples was prepared to minus 1mm in size by crushing and grinding. The important factors in the KC3 Knelson Concentrator test were examined in terms of the variations such as number of treatment, feed rate, rotation speed of bowl(G force), water flow rate, pre-removal of magnetic minerals, feed size and feed grade. According to the result of experiment, it shows that the important technical variations are limited in terms of number of treatment, feed rate, feed size and feed grade. The final result shows that the KC3 Knelson Concentrator obtains the scheelite pre-concentrate of about $3%WO_3$ grade and 90% recovery, respectively, from the feed containing about $0.8-1.0%WO_3$ grade.

• Korean Journal of Mineralogy and Petrology
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• v.36 no.2
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• pp.107-115
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• 2023

Cobalt can be released into the natural environment as industrial waste from the alloying industry and as acid mine drainage, and it is also a radionuclide (⁶⁰Co) that constitutes high-level radioactive waste. Smectite is a mineral that can be useful for adsorption and isolation of this element. In this study, Cheto-type montmorillonite (Cheto-MM), which is the source clays of The Clay Mineral Society (CMS) and already well-characterized, was used. The effect of the adsorption site affected by the presence of interlayer water on the adsorption of cobalt before and after dehydration by heating was evaluated and the adsorption mechanism of cobalt on Cheto-MM was studied by applying adsorption kinetics and adsorption isotherm models. The results showed that the adsorption characteristics changed with dehydration and subsequent shrinkage, and cobalt was found to be adsorbed at the edge of Cheto-MM for about 38% and adsorbed at the interlayer site for about 62%, suggesting that the cobalt adsorption of Cheto-MM is significantly influenced by the interlayer. By applying the adsorption kinetic models, the cobalt adsorption kinetics of Cheto-MM is explained by a pseudo-second-order model, and the concentration-dependent adsorption was best described by the Langmuir isotherm adsorption model. This study provides basic knowledge on the adsorption characteristic of cobalt on montmorillonite with different adsorption sites and is expected to be useful in predicting the adsorption behavior of smectite in high-level radioactive waste disposal sites in the future.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.8 no.1
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• pp.69-78
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• 2013

Settled lifestyle as important to health and healing to medical tourism and wellness tourism in the 21st century has emerged as the best promising service industry. Jeju Island has a variety of local resources, and the directions was considered to spa industry promotion application it. Jeju Island has a variety of local resources which can be used for spa industry promotion. Jeju Island's beautiful natural environment, mineral resources, water resources, biological resources, agricultural products, traditional folk remedies available in Jeju's spa treatments. Using the local resources of Jeju, 'Jeju specialized spa treatments' can develop of 12 kinds of spa treatments. Namely, thalssotherapy, stone therapy, black sand poultice, hot-floored therapy using volcanic soil, thalassotherapy, drinking therapy, hydrotherapy, herbal/medicinal plants poultice, forest therapy, Spa cuisine, facial beauty, diet therapy. 12 kinds of Jeju specialized spa treatments development and service to the local resources of basic research on the physical and chemical characteristics, product development, clinical trials, efficacy studies should precede. In addition, customized spa services programs should be developed considering the propensity of customers, customer needs, and a spa type. And standardized program of spa services and need a manual painter. Medical tourism and wellness tourism in conjunction with efforts to be considered in order to increase the competitiveness of the spa industry in Jeju.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.61-66
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• 2006

Over the past 20 years there has been a revolution involving the use of nano or macro size particles as drainage and retention systems during the manufacture of paper. More recently a group of patented technologies called Synthetic Mineral Microparticles (SMM) has been invented and developed. This system has potential to further promote the drainage of water and retention of fine particles during papermaking. Prior research, as well as our on preliminary research showed that the SMM system has advantages in both of drainage and retention compared with montmorillonite (bentonite), which one of the most popular materials presently used in this kind of application. In spite of the demonstrated advantages of this SMM system, the properties and activity of SMM particles in the aqueous state have not been elucidated yet. Streaming current titrations with highly charged polyelectrolytes were used to measure the charge properties of SMM and to understand the interactions among SMM particles, fibers, fiber fines, and cationic polyacrylamide (cPAM) as a retention aid. It was found that pH profoundly affects the charge properties of SMM, due to the influence of Al-ions and the Si-containing particle surface. SEM pictures, characterizing the morphology, geometry and size distribution of SMM, showed an broad distribution of primary particle size. Dilution of SMM mixturee appeared to wash out particles smaller than 100 nm from the surface of larger particles, which themselves appeared to be composed of fused primary particles. DSC thermoporometry was used to measure the size distribution of nanopores within SMM particles.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.475-481
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• 2013

Although the lightly burnt MgO at $850{\sim}1000^{\circ}C$ has expansibility, it does not lead to unsound concrete. The expansion of MgO could compensate for shrinkage of concrete for a long-term, because the hydration of MgO occurs at a slow pace. Recently, the study and application of mineral admixture such as fly ash and blast furnace slag have increased for the hydration heat reduction, durability improvement, and reducing $CO_2$ emission in the construction industry. Thus, it is necessary to research on the concrete that contains both a mineral admixture and MgO as an expansion agent. This study investigates fundamental properties of fly ash concrete with lightly burnt MgO through various experiments. The adiabatic temperature test results showed that the fly ash concrete with MgO of the 5% replacement ratio had the slower pace of the temperature rise and the lower final temperature than the fly ash concrete. The influences of MgO on long-term compressive strength varied depending on water-binder ratio, and the long-term length change test results indicated the expansion effects of the FA concrete containing MgO.

• The Korean Journal of Food And Nutrition
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• v.34 no.3
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• pp.255-262
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• 2021

Centella asiatica (CA) is a vegetable that has been used for medicinal purposes for a long time, but it is not well known in Korea. In this study, the approximate analysis, physicochemical properties, free sugars, free amino acids and minerals of native and improved CA cultivated in Chungju area were measured. And the antioxidant contents and activities of CA solvent extracts were measured. There was no significant difference between native and improved species. As for the characteristics of CA, it was confirmed that the improved species had a large weight, size and a tough texture. Glucose was detected in native CA, fructose, glucose and sucrose were detected in improved species. A total of 15 free amino acids were detected and the content was slightly higher in improved species than in native species. The mineral content in CA was slightly higher in the improved species, and the detected minerals were Na, P, Ca, K, Mg and Fe. Polyphenols, ascorbic acid and flavonoids in each extraction solvent (water, 70% and 100% ethanol) were all higher in the improved species than in native species. And it was found that the antioxidant activities of ethanol extracts were higher than that of water.

• KSBB Journal
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• v.26 no.1
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• pp.27-32
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• 2011

For the development of functional food and cosmetics using hot water extract of Muraenesox cinereus's skin, contents of vitamin, amino acid and element, and antioxidant activity were investigated. The results are shown as follows: among vitamins, A(0.21mg/100 g), C (78.12mg/100 g), $D_3$ (0.03 mg/100 g), E (1.97 mg/100 g) and Niacin (2.53mg/100 g) were detected, respectively.Mineral contents were an order of K > P > Na > Mg > Ca > Fe and Zn. Contents of total amino acids were an order of Pro > Gly > Arg > Glu > Phe > Ala. Especially, the sum of total amino acids was 27.17 mg/100 mL, which was about 4.0 fold higher than that of free amino acid. DPPH radical scavenging activity of hot water extract of M. cinereus's skin at 25 mg/mL was 63.5% and did not increase at above 50 mg/mL. Activities of antioxidant enzymes in the liver of ethanol-treated rats using hot water extract of M. cinereus's skin were investigated. Compared to control group, activities of ADH and GSH-px were decreased. In the case of CAT and SOD activity, they were increased. These results showed that the hot water extract of M. cinereus's skin can be applied to raw macterial for functional food and cosmetics.

• Journal of the Korean Institute of Gas
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• v.19 no.2
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• pp.54-65
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• 2015

China holding the world largest shale resources, has been trying to develop their domestic shale gas fields mainly with its NOCs. Chinese shale industry looks likely to have high potential to grow in the future, considering the eager support of Chinese government and the rapid development of relevant technologies by NOCs. However, there are opposite opinions as well that Chinese shale gas could not play a positive short-term results because of the complexity of structural geology, inadequacy of water resources and related infrastructure. Recently, Korean companies began to be interseted in Chinese shale gas industry, because of the special relationships with Korean industries in terms of geographic proximity and better opportunities due to the early phase of shale gas business in China. In this study, it was tried to help those companies looking out of future Chinese shale gas industry that surveying current status and problems of Chinese shale gas industry and relevant industries and investigating some trials and policies driven by China government. As a result, the various and long-term problems in Chinese shale development were reviewed and the active supports and polices of Chinese government, NOC's trials for establishments of their independent technologies and the cooperation with foreign companies or M&As were also investigated.

• Applied Biological Chemistry
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• v.41 no.2
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• pp.147-152
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• 1998

As a part of investigation for utilizing seafood processing by-products as a functional food source, we investigated the processing condition (extraction methods and autoclaving time) of a functional calcium-based powder from fish bones and its characteristics. The calcium-based powder from Alaska pollack bone by autoclaving in water showed lower in the calcium content and higher in the yields and the soluble calcium ratio than those from fish bone by the other calcium extraction methods. As the autoclaving time elapsed up to 40 min, the content and soluble ratio of calcium increased, and the yield decreased. On the other hand, there were no difference found in those among calcium-based powders autoclaved for 40 min and over. Judging from the results, the calcium-based powder from Alaska pollack autoclaved in water for 40 min (CAP) was superior to those from fish bone by the other processing condition. The CAP was mostly solublized by shaking $(37^{\circ}C)$ for 1 hr at the acidic condition (pH 2.0). The soluble calcium ratio of acid-solublized CAP was about 59% by shaking $(37^{\circ}C)$ for 3 hr and over at the neutral condition (pH 7.0).