• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.216-219
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• 2008

As a future clean substitute energy, the Gas hydrate development projects are world widely carried out to prepare the shortage of petroleum and natural gas resources. The OIIP of gas hydrate is estimated approximately 10 Trillion LNG equivalent ton and it reaches almost the amount of 5 thousand years use for the world people. To develop the commercial production technology, several research projects like Malik and Alaska project have been carried by several advanced countries and teams, but nobody have succeeded it yet due to the technical problems and the high risks. The technologies developed up to now for the hydrate production are categorized to four methods, such as depressurization method, thermal recovery method, inhibitor injection method and replacement method. As these methods are highly related to the costs and the environmental problems, many other researches including the safety, environment and disaster prevention are actively fulfilled as well.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.75.1-75.1
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• 2011

Coal gasification is considered as one of the most prospective technologies in energy field since it can be utilized for various products such as electricity, SNG (Synthetic Natural Gas or Substitute Natural Gas) and other chemical products. Among those products from coal gasification, SNG is emerging as a very lucrative product due to the rising prices of oil and natural gas, especially in Asian countries. The process of SNG production is very similar to the conventional IGCC in that the overall process is highly dependent on the type of gasifier and coal rank. However, there are some differences between SNG production and IGCC, which is that SNG plant requires higher oxygen purity from oxygen plant and more complex gas cleanup processes including water-gas shift reaction and methanation. Water-gas shift reaction is one of the main process in SNG plant because it is a starting point for the latter gas cleanup processes. For the methanation process, syngas is required to have a composition of $H_2$/CO = 3. This study reviewed various considerations for water-gas shift process in a conceptual design on an early stage like a feasibility study for a real project. The factors that affect the design parameters of water-gas shift reaction include the coal properties, the type of gasifier, the overall thermal efficiency of the plant and so on. Water-gas shift reaction is a relatively proven technology compared to the other processes in SNG plant so that it can reduce technological variability when designing a SNG project.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.10
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• pp.1002-1010
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• 2015

Natural gas hydrates are newly emerging as an environment-friendly source of energy to substitute for fossil fuels in the 21stcentury.NGHs are reported to holds much amounts of natural gas (up to 182 standard volumes of gas per volume of hydrate); they are easy to store and safe to carry at about minus 20 degree Celsius under atmospheric pressure because of the self-preservation phenomenon of gas hydrates. The transporting method by gas-ice-hydrate ship carriers has been introduced and developed by a variety of industry and research institutions. Our team has been conducted to develop NGH total systems, including a breakthrough NGH carrier for sea transportation, since 2011. The NGH pellet carrier does not require a separate cooling system for cargo, and the initial temperature is maintained through insulation of the cargo tanks throughout the transport to the final destination. The heat conducted from the exterior and passing through the insulation material of the hull should be cut off as much as possible, but heat inflow inside the cargo tank from an external source is inevitable during transport. In this study, the heat transfer in a cargo tank of a 115K NGH carrier was analyzed through simulation with a commercial CFD code to estimate the boil-off gas/boil-off rate on the developed carrier and understand major hazards that could significantly impact the safety of the vessel.

• Journal of the Korean Graphic Arts Communication Society
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• v.12 no.1
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• pp.159-168
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• 1994

The Aggregation State of thin vapor deposite Film made by Cyanine Dye were changed into Monomeric molecular state(M) and Dimeric Aggregation(D) at the acidic treatment, into reversible H-Aggregation (H) at alkalic gas or heat treatment. Photo-electric properties were higher H than D and M, this stats were effective in enhancing Photoelectric-conversion characteristic. Substitute group of Meso-Position being stronger electronic Donors, Electronic density is higher and Electric conductivity is enhanced, we confirmed Oscillator Strength calculated by PPP-Molecular Orbital Calculation and Absorption Spectra at solvent stats were agreed good.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.2
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• pp.94-94
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• 1999

Natural gas is considered to be on e of the most promising candidates for a clean substitute fuel and a great amount of research on the compressed natural gas(CNG) fueled vehicle has been performed. In this s tudy, we try to understand the property of CNG fuel with using CNG engine experiment. In order to present the direction and application of CNG, we experiment with various operating conditions that is, spark timing, A/F ratio, air quantity and fuel quantity, etc. 11,967 cc engine was used in the experiment and the engine fuel ratio was determined in the way that the performance of dedicated CNG engine is corresponded to that of existing diesel engine. The performance and dedicated CNG engine were measured by changing the fuel injection timing. The dedicated CNG engine was proved to be good in describing the experimental results and according to the actual road test, acceleration and constant speed driving for dedicated CNG engine was better than existing diesel engine.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.74.1-74.1
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• 2011

As a demand for energy, many studies are increasing about energy resource. One of these resources is coal which reserves of underground. A lot of research to use coal is going on as method of IGCC (Integrated Gasification Combined Cycle). In addition, SNG(Substitute Natural Gas) and IGFC (Integrated Gasification Fuel Cell) are also being developed for fuel & electricity. This technology which uses synthesis gas after gasification is to produce electricity from the Fuel Cell. At this point, important thing is the components of synthesis gas. The main objective is to increase the proportion of methane and hydrogen in synthesis gas. The catalytic gasification is suitable to enhance the composition of methane and hydrogen. In this study, Exxon Predevelopment catalyst gasification study was served as a good reference and then catalytic gasification simulation process is conducting using Aspen Plus in this research. For this modelling, kinetic value should be calculated from Exxon's report which is used for modeling catalytic gasification. Catalytic gasification model was performed by following above method and was analyzed by thermodynamic method through simulation results.

• Journal of Biosystems Engineering
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• v.22 no.2
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• pp.189-198
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• 1997

In order to find out the potential of LP gas as a substitute fuel for small fm engine, experiments were carried out with a four-stroke spark-ignition engine which was modified from a kerosene engine mounted on the power tiller. Performance characteristics of kerosene and LP gas engine such as torque, volumetric efficiency fuel consumption rate, brake thermal efficiency, exhaust temperature, and carbon monoxide and hydrocarbon emissions were measured and analyzed under various levels of engine speed and compression ratio. The results were summarized as follows. 1. It showed that forque of LPG engine was 41% lower than that of kerosene engine with the same compression ratio, but LPG engine with compression ratio of 8.5 it was showed similar torque level to kerosene engine with compression ratio of 4.5. 2. Fuel consumption of LPG engine was reduced by about 5.1% and thermal efficiency was improved by about 2% compared with kerosene engine with the same compression ratio. With the incrasing of compression ratio in LPG engine fuel consumption rate decreased and thermal efficiency increased. 3. Exhaust temperature of LPG engine was about 15% lower than that of kerosene engine. Concenrations of emissions from LPG engine was affected insignificantly by compression ratios, and carbon monoxide emissions from the LPG engine was not affected by engine speed so much. The carbon monoxide and hydrocarbon emissions from LPG engine were about 94% and 66% lower than those of kerosene engine, respectively.

• Journal of Animal Environmental Science
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• v.5 no.1
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• pp.37-44
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• 1999

This study was carried out to improve utilization of substitute fly-ash in bedding material of animal waste treatments. The amount used of fly-ash used in a pigpen or beef stall was 50% lower than that of existing bedding material of animal waste treatments. From the results, substitution effect of fly-ash put over the floor of the stable became much better. Effects of processed fly ash as a spread straw decreased ammonia(NH3) and Hydrogensulfide (H2S) gas at beef stall, but there was no benefit of replacement terms. Effect of processed fly ash as a spread straw increased 4∼5 times replacement terms more than control NH3 and H2S gas was decreased. A lot of maggots and porasites were grown at sawdust pig farm, but fly ash inhibited to grow maggots and paraeters. In conclusion, as substituting fly-ash for 5% sawdust(DM basis) in making animal waste into a compost with fly ash, we can reduce the sawdust purchasing costs and produce the high quality of a compost, especially a pollutant as NH3 and H2S gas, etc. from the process of biodegradation, and as substituting fly-ash(1,540 won per ton ; can be extended the replacement period of spreading straw approximatively 4∼5 times) for sawdusts(111,000 won per ton) will increase a real income in livestock house.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.5
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• pp.445-452
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• 2008

DME(Dimethyl ether) Dimethyl Ether (DME) is a new clean fuel and an environmental-benign energy resource. In comparison with other fuels, DME rapidly decomposes into carbon dioxide ($CO_2$) and water in the atmosphere without forming ozone. It can be manufactured from various energy sources including natural gas, coal, biomass and spent plastics. In addition to its environmentally friendly properties, DME is considered as one of the most promising candidates for the substitute of LPG and diesel fuel. In this work, we will be studied to find optimized condition for the catalyst of DME energy manufacture from hydrogen and carbon oxide and its chemical and physical characteristics.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.8
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• pp.1164-1171
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• 2012

Recently, machine olfactory systems as an artificial substitute of the human olfactory system are being studied actively because they can scent dangerous gases and identify the type of gases in contamination areas instead of the human. In this paper, we present an effective design method for the gas identification system. Even though dimensionality reduction is the very important part, in pattern analysis, We handled effectively the dimensionality reduction by grouping the sensors of which the measured patterns are similar each other, where genetic algorithms were used for combination optimization. To identify the gas type, we constructed the hierarchical rule base with two frames by using rough set theory. The first frame is to accept measurement characteristics of each sensor and the other one is to reflect the identification patterns of each group. Thus, the proposed methods was able to accomplish effectively dimensionality reduction as well as accurate gas identification. In simulation, we demonstrated the effectiveness of the proposed methods by identifying five types of gases.