• Economic and Environmental Geology
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• v.47 no.3
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• pp.275-289
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• 2014

Recent scaled-up onshore and offshore field production tests revealed that the expectancy to produce gas from the gas hydrate deposits is gradually increasing, recognizing its potentials as one of the future energy resources. The total produced gas was approximately $480m^3$ by the hot water circulation method for 6 days' operation in Mallik 2002 project in Canada. In Mallik 2006-2008 project, the gas was successfully produced stably by the depressurization method for 6 days, up to $13,000m^3$ cumulatively. The depressurization method applied in the Mallik test was revealed as an effective way to produce gas from gas hydrates. The Alaska North Slope field trial in 2012 to inject mixed gas of $CO_2$ and $N_2$ to exchange $CH_4$ was successfully completed for the first time to produce maximum $1,270m^3$ per day. The remarkable achievement is that Japan has completed first offshore production test in the Eastern Nankai Trough, and produced approximately $120,000m^3$ of methane by the depressurization method for 6 days in March 2013. The technical challenges and uncertainties obtained from Nankai Trough production test give Korea more considerations in the aspects of well completion, reservoir formation and seafloor stability, sand control, flow assurance, and etc., due to the different geological environments and geomechnical properties in Ulleung Basin in Korea.

• Korean Journal of Food Science and Technology
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• v.35 no.2
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• pp.320-324
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• 2003

Combined effect of modified atmosphere packaging and gamma irradiation on color characteristics of emulsion-type cooked pork sausage were investigated. Nitrosomyoglobin (NO-Mb) contents and CIE color values of sausage with aerobic, $CO_2, \;N_2$, and $CO_2/N_2$ packagings were observed during storage for 4 weeks. Irradiation reduced NO-Mb content in sausage, inducing denitrosylation of nitrite-cured meats. $CO_2$ and $CO_2/N_2$ packagings were effective for maintaining NO-Mb content. In CIE color values, $a^*$ was significantly reduced by irradiation at 5 kGy and above. The $a^*$ values of sausages with $CO_2$ and $CO_2/N_2$ packagings were higher than those of aerobic or $N_2$ packaging. Results indicated that modified atmosphere packaging, such as $CO_2$ or $CO_2/N_2$ packaging, was effective for minimizing the loss of red color in sausage caused by irradiation.

• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.5
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• pp.413-430
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• 2011

Consideration on the explosion resistant design of infrastructure has increased in the recent years. The explosion load is caused by gas explosion or bomb blast. In this study an analytical model is developed, whereby the tunnel structure is divided in several elements that are schematized as single degree of freedom mass-spring-dashpot systems on gas explosion. Using this simple model a sensitivity analysis has been carried out on tunnel structure design parameters such as explosive peak pressure, duration of the load, thickness of structure, burial depth. Finite element method was used to investigate the dynamic response and plastic zone of a tunnel under gas explosion. And it was found from the comparison of the analysis results that there are slight differences in the response of the intermediate wall between the single degree of freedom mass-spring-dashpot model and FEM.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.188-191
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• 2008

There have been many methods for producing natural gas from gas hydrate reservoirs in permafrost and sea floor sediments. It is well knownthat the depressurization should be a best option for Class 1 gas hydrate deposit, which is composed of tow layers: hydrate bearing layer and an underlying free gas. However many of gas hydrate reservoirs in sea floor sediments are classified as Class 2 that is composed of gas hydrate layer and mobile water, and Class 3 that is a single gas hydrate layer. The most appropriate production methods among the present methods such as thermal stimulation, inhibitor injection, and controlled oxidation are still under development with considering the gas hydrate reservoir characteristics. In East Sea of Korea, it is presumed that the thick fractured shale deposits could be Class 2 or 3, which is similar to the gas hydrate discovered offshore India. Therefore it is needed to evaluate the possible production methods for economic production of natural gas from gas hydrate reservoir. Here we would like to present the production of natural gas from gas hydrate deposit in East Sea with industrial flue gases from steel company, refineries, and other sources. The existing industrial complex in Gyeongbuk province is not far from gas hydrate reservoir of East Sea, thus the carbon dioxide in flue gas could be used to replace methane in gas hydrate. This approach is attractive due to the suggestion of natural gas productionby use of industrial flue gas, which contribute to the reduction of carbon dioxide emission in industrial complex. As a feasibility study, we did the NMR experiments to study the replacement reaction of carbon dioxide with methane in gas hydrate cages. The in-situ NMR measurement suggeststhat 42% of methane in hydrate cages have been replaced by carbon dioxide and nitrogen in preliminary test. Further studies are presented to evaluate the replacement ratio of methane hydrate at corresponding flue gas concentration.

• Journal of the Korean Magnetics Society
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• v.18 no.1
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• pp.14-18
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• 2008

Bismuth-substituted yttrium iron garnet(Bi:YIG) films, which show excellent magnetic and magneto-optical properties as well as low optical losses by optimizing their deposition and post-annealing condition, have been attracting great attention in optical device research area. In this study, the Bi:YIG thick films were deposited with the aerosol deposition method for the final purpose of applying them to optical isolators. Since the aerosol deposition is based on the impact adhesion of sub-micrometer particles accelerated by a carrier gas to a substrate, the flow rate of carrier gas, which is in proportion to mechanically collision energy, should be treated as an important parameter. The Bi:YIG($Bi_{0.5}Y_{2.5}Fe_5O_{12}$) particles with $100{\sim}500$ nm in average diameter were carried and accelerated by nitrogen gas with the flow rate of 0.5 l/min${\sim}$10 l/min. The coercive force decreased from 51 Oe to 37 Oe exponentially with increasing gas flow rate. This is presumably due to the fact that the optimal collision energy results in reduction of impurity and pore, which makes the film to be soft magnetically. The saturation magnetization decreased due to crystallographical distortion of the film with increasing gas flow rate.

• Resources Recycling
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• v.23 no.4
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• pp.37-46
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• 2014

Carbon dioxide generated from construction materials and construction material industry among the fields of construction is approximately 67 million tons. It is about 30% of the carbon dioxide generated in the fields of construction. In order to reduce carbon dioxide in the fields of construction, it is necessary to control the use of fossil fuel consumed and decrease carbon emission by reducing the secondary and tertiary curing generating carbon dioxide in construction material industry. Therefore, this study manufactured mortar by having cement as the Plain and substituting three binding materials up to 50% and then adopted different curing methods to analyze congelation and strength characteristics. Test results for strength property by changing binding materials showed that specimens with blast furnace slag, CSA 15% and CAMC 5% resulted in positive effect for strength.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.4
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• pp.178-184
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• 2010

The $12CaO{\cdot}7Al_2O_3$(C12A7) powders were successfully synthesized using combustion method with microwave-assistant and C12A7:H were fabricated by post-annealed process in Ar/H atmosphere. X-ray diffraction patterns and TGDSC were used for investigating to the precursors of crystalline and reaction depending on temperature. C12A7:H that was treated post-annealed process were investigated TG-MS and Hall-measurement for confirming H ions doping and checking electrical resistivity of C12A7:H. H ion substituted to $O^{2-}$ ions in the C12A7 cages were confirmed at $289.5^{\circ}C$ by TG-MS and C12A7:H calcined at $1000^{\circ}C$ in Ar/H=8:2 atmosphere for 8~10 h has low electrical resistivity about $10^2{\Omega}{\cdot}cm$ at room temperature.

• Analytical Science and Technology
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• v.16 no.5
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• pp.368-374
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• 2003

Halogen gases such as $BCl_3$ and $CF_4$ are among the most problematic gases used in semiconductor process. They raise serious environmental and health problems due to their extreme toxicity. This study is to develop a method to effectively remove those gases during the process by using various types of inorganic gas adsorption agents such as zeolite A, modified AgA zeolite, ZnO, and $AgMnO_3$, which have not been attempted in the conventional methods. The removal efficiencies of the gases were both qualitatively and quantitatively measured by a FT-IR spectrophotometer. The whole device for the measurement has been designed and built in our lab. The removal efficiencies of the gases were compared between those used resins. The experimental result revealed that ZnO showed the best removal efficiency for BCl3 gas that had removed 0.094 g per 1 g of the resin used. For $CF_4$ gas, none of the solid resins was able to remove the gas effectively. However, liquid $CHCl_3$ showed some removal ability of the $CF_4$ gas.

• Korean Journal of Food Science and Technology
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• v.34 no.5
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• pp.792-798
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• 2002

Investigations on the microbiological, physicochemical, and sensory characteristics of seasoned Galbi using various packaging methods during storage at $-1^{\circ}C$ revealed no significant differences in pH values and acidities of seasoned Galbi depending on packaging methods and storage periods. Increments of thiobarbituric acid values of seasoned Galbi with non-evacuated packaging and modified atmosphere packaging were superior to those of vacuum packaging and double-film vacuum packaging during storage. Seasoned Galbi with non-evacuated packaging showed the highest volatile basic nitrogen value, and total plate count significantly increased compared to other packaging methods after 15 days storage. Coliform bacteria showed an average count of 2.35 log CFU/g at the beginning of storage, which increased slightly from 7 to 15 days, and was maintained under 4.0 log CFU/g after 15 days storage. The sensory evaluation revealed that non-evacuated packaging scored relatively lower than other methods in color, flavor, off-odor, and overall acceptability after storage.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.380-386
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• 2011

Tip burn has been reported as one of the most serious physiological disorder in Chinese chives (Allium tuberosum Rottl.) cultivated in plastic film house. In this study, a physiography and chemical properties of 132 plastic film house soils were investigated to elucidate factors affecting tip burn symptom. Also influence of soil properties on tip burn was statistically determined by path analysis and association analysis including a chi-square test or logistics analysis. Probability distribution of inorganic aqueous species, such as ammonia (g) was calculated using MINTEQ program. Soil order and chemical properties, especially pH, exchangeable calcium and inorganic nitrogen, showed a significant relationship with tip burn of Chinese chives. Tip burn symptoms occur mainly in an alkaline soil classified as Alfisols. Result of linear regression and path analysis exhibited that formation of ammonia (g) from soil solution depend upon soil pH and were associated with ammonium resulting from soil organic matter or nitrate. These results indicate that tip burn symptom of Chinese chives is directly affected by ammonia gas originated from alkaline soil condition.