• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.708-715
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• 2017

Recently, in order to meet the stricter emission regulations, the proportion of after-treatments for vehicles and vessels has been increasing gradually. The objective of this study is to investigate the improvement of $CH_4$ reduction ability of natural gas oxidation catalyst (NGOC), which reduces toxic gases emitted from CNG buses. Thirteen NGOCs were prepared, and the conversion performance of noxious gases according to the type of supports, the loading amount of noble metal, and surfactant and aging were determined. Support Zeolite supported on No. 3 $NGOC(1Pt-1Pd-3MgO-3CeO_2/(46TiO_2+23Al_2O_3+23Zeolite)$ is an anionic alkali metal/earth metal component that improved the oxidation reactivity between CO and NO and noble metal dispersion, and thus enhanced the $CH_4$ reduction ability. As the loading amount of Pd, a noble metal with a high selectivity to $CH_4$, was increased, the number of reaction sites was increased and the ability to reduce $CH_4$ was improved. No. 11 $NGOC(1Pt-1Pd-3MgO-3CeO_2/(Z20+Al80)$(pH=8.5), to which nitrate surfactant had been added, exhibited well dispersed catalyst particles with no agglomeration and improved the $CH_4$ reduction ability by 5-15%. The $NGOC(2Pt-2Pd-3Cr-3MgO/90Al_2O_3)$(48h aging), which was mildly thermal aged for 48h, increased the $CH_4$ reduction ability to about 10% or less as compared with No. 12 NGOC(Fresh).

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1144-1152
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• 1999

In order to investigate the content of preservative components occurred naturally in foods, the content of benzoic acid and sorbic acid in 48 kinds of plants which used as commercial teas or spices was determined according to the method of 'Korean Food Code' and analyzed with a gas chromatograph. The recoveries of the benzoic and sorbic acid were 82.5% and 94.5%, respectively. The naturally occurring benzoic acid was less than 50 ppm in most of the plants used as commercial teas. The content of benzoic arid in spices and the content of sorbic acid in teas or spices were less than 10 ppm. The average contents of benzoic acid and sorbic acid in edible part of each plant were as followed ; leaf 12.5 ppm and 8.1 ppm, root 16.8 ppm and 3.7 ppm, seed 9.8 ppm and 2.3 ppm, fruit 33.8 ppm and 1.2 ppm, fungus 18.3 ppm and 14.6 ppm, respectively. The contents of benzoic acid and sorbic acid in several plants used at teas or spices extended over a wide range.

• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.436-442
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• 2017

Fischer-Tropsch synthesis is the technology of converting a syngas (CO+$H_2$) derived from such as coal, natural gas and biomass into a hydrocarbon using a catalyst. The catalyst used in the Fischer-Tropsch synthesis consists of active metal, promoter and support. The types of these components and composition affect the reaction activity and product selectivity. In this study, we manufactured an iron catalyst using ${\gamma}-Al_2O_3/SiO_2$ mixed support (100/0 wt%, 75/25 wt%, 50/50 wt%, 25/75 wt%, 0/100 wt%) by an impregnation method to investigate how the composition of ${\gamma}-Al_2O_3/SiO_2$ mixed support effects on the reaction activity and product selectivity. The physical properties of catalyst were analyzed by $N_2$ physical adsorption and X-Ray diffraction method. The Fischer-Tropsch synthesis was conducted at $300^{\circ}C$, 20bar in a fixed bed reactor for 60h. According to the results of the $N_2$ physical adsorption analysis, the BET surface area decreases as the composition of ${\gamma}-Al_2O_3$ decreases, and the pore volume and pore average diameter increase as the composition of ${\gamma}-Al_2O_3$ decreases except for the composition of ${\gamma}-Al_2O_3/SiO_2$ of 50/50 wt%. By the results of the X-Ray diffraction analysis, the particle size of ${\alpha}-Fe_2O_3$ decreases as the composition of ${\gamma}-Al_2O_3$ decreases. As a result of the Fischer-Tropsch synthesis, the CO conversion decreases as the composition of ${\gamma}-Al_2O_3$ decreases, and the selectivity of C1-C4 decreases until the composition of ${\gamma}-Al_2O_3$ was 25 wt%. In contrast, the selectivity of C5+ increases until the composition of ${\gamma}-Al_2O_3$ is 25 wt%.

• Korean Journal of Pharmacognosy
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• v.40 no.3
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• pp.196-204
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• 2009

This study was carried out to investigate the in vivo and in vitro inhibitory effect of a traditional herbal complex (HC) extract prepared from a mixture of four oriental herbs (Dioscorea Rhizoma, Glycine soja Sieb. et Zucc, Bombycis corpus, Fermented Glycine soja) that have been widely used for the treatment and prevention of diabetes mellitus on hyperglycemia. The water extract of HC showed potent inhibitory effect on $\alpha$-glucosidase with $IC_{50}$ value of 1.24 mg/mL. Additionally, the ethanol extract of HC was also found to exhibit significant inhibitory effect against protein tyrosine phosphatase $1{\beta}$ ($PTP1{\beta}$), which is known as a major regulator of both insulin and leptin signaling. In the $PTP1{\beta}$ inhibitory assay, the most active n-hexane fraction obtained from the ethanol extract of HC, was identified as a mixture of fatty acid derivatives by gas chromatography-mass spectrometry (GC-MS). In high-fat diet-low dose streptozotocin (STZ)-induced diabetic rat, the water extract of HC improved the oral glucose intolerance as compared with rosiglitazone. HC also caused a marked decrease of body weight and fasting blood glucose and a significant improvement on glucose tolerance in metabolic syndrome mice model. These findings support that this traditional HC may be useful in the control of blood glucose in diabetes mellitus and metabolic syndrome.

• Journal of agricultural medicine and community health
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• v.21 no.1
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• pp.61-73
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• 1996

This study conducted to determine the attitude on environment pollution by Pohang city citizens. 1,059 Pohang city citizens in the age group 20 and over were chosen and surveyed by officials's interview at Up, Myun and Dong during the period 6 September to 20 September 1995. The issue problems to be solved in Pohang city were traffic control 47.3%, environment pollution 22.7%, cultural institutions 11.6%, water service 9.9%, education system 5.1% and community security 2.1%. The 55.1% of subjects responded that responsibility for environment pollution is every citizens duty. The trash from houses were 'garbage'(48.1%), 'waste of life'(21.8%), 'reuse trash'(15.6%) and 'one use thing'(14.5%) in order. The 66.9% of subjects responded that the trash's standard envelopes can be easily tear and its texture is not good. The respondents sometimes or often had experienced foreign bodies, sediment in the water service supply. The 45.9% of the respondents use natural water as drinking water, and the water service supply(26.7%), underground water(17.0%) and buying water(9.3%) were followed. Pertaining to the air pollution(by percent) was pollution of the steel industry complex 78.0%, combustive gas 16.6% and construction dust 1.7%. The respondents at southern district complained of respiratory tract by air pollution and the respondents at northern district complained of the visual disturbance and the offensive odor(P<0.05). Water pollution problem is factory's wastewater 56.2%, home wastewater 36.4% and livestock's wastewater 5.6% in order. The respondents at southern district complained of the noise pollution by airplanes and factories at the afternoon and the respondents at northern district complained of the noise pollution by vehicles(P<0.05).

• Journal of Korean Society of Environmental Engineers
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• v.30 no.10
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• pp.999-1005
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• 2008

The main reaction for soil washing with using sodium hydroxide(NaOH) and hydrogen peroxide(H$_2$O$_2$) was desorption and flotation of petrochemical contaminant by means of oxygen bubble. We found the rate of decomposition by rate constant according to various temperature. For the purpose of optimizing the operation factor, we examined the effect of concentration of NaOH and H$_2$O$_2$, washing time, and soil:water ratio. The rate of decomposition for H$_2$O$_2$ in liquid phase is the first order reaction by its concentration. The rate constant of k$_1$ was 0.9439 $\times$ exp(-1376.82/RT) when concentration of NaOH was lower than 0.1 M, and the rate constant of k$_2$ was 17.3588 $\times$ exp(-2320.06/RT) when it was higher than NaOH of 0.1 M. It found that NaOH was facilitated at the beyond of specific concentration. We confirmed the optimum concentration of NaOH/H$_2$O$_2$ by means of rate constants during soil washing. Also, the optimum conditions during soil washing were washing time of 15 min, soil : water ratio of 1 : 3, and NaOH/H$_2$O$_2$ concentration of 0.25 M/0.1 M.

• Economic and Environmental Geology
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• v.51 no.1
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• pp.67-76
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• 2018

This study reviews three eco-friendly energy towns with hybrid thermal energy supply systems and borehole thermal energy storage (BTES) in Canada and Denmark. The district heating and cooling systems were designed by using multi-source energy for the higher efficiency and reliability as well as environment. ADEU (Alexandra District Energy Utility) located at the developing area in the city of Richmond, Canada was designed to supply district energy with the installation of 726 borehole heat exchangers (BHEs) and a backup boiler using natural gas. DLSC (Drake Landing Solar Community) located in the town of Okotoks, Canada is a district system to store solar thermal energy underground during the summer season by seasonal BTES with 144 BHEs. Brædstrup Solpark district heating system located in Denmark has been conducted energy supply from multiple energy sources of solar thermal, heat pump, boiler plants and seasonal BTES with 48 BHEs. These systems are designed based on social and economic benefits as well as nature-friendly living space according to the city based energy perspective. Each system has the energy center which distribute the stored thermal energy to each house for heating during the winter season. The BHE depth and ground thermal storage volume are designed by the heating and cooling load as well as the condition of ground water flow and thermophysical properties of the ground. These systems have been proved the reliance and economic benefits by providing consistent energy supply with competitive energy price for many years. In addition, the several expansions of the service area in ADEU and Brædstrup Solpark have been processed based on energy supply master plan. In order to implement this kind of project in our country, the regulation and policy support of government or related federal organization are required. As well as the government have to make a energy management agency associated with long-term supply energy plan.

• Journal of Food Hygiene and Safety
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• v.32 no.5
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• pp.381-388
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• 2017

In this study, we investigated the levels of natural preservatives of benzoic acid, sorbic acid, and propionic acid in spices. The quantitative analysis was performed using high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) for benzoic acid and sorbic acid and gas chromatography-mass spectrometry (GC-MS) for propionic acid. The sample was extracted with ethanol using sonication, then centrifuged and evaporated to dryness and redissolved to 1 mL with ethanol to use for the instrumental analysis. The analytical method was validated based on linearity, recovery, limit of detection (LOD), and limit of quantification (LOQ). This method was suitable to determine low amounts of naturally occurring preservatives (benzoic acid, sorbic acid, and propionic acid) in various spices. Benzoic acid, sorbic acid, and propionic acid were found in 165 samples, 88 samples, and 398 samples, respectively from the total of 493 samples. The concentration of benzoic acid, sorbic acid, and propionic acid were ranged at ND-391.99 mg/L, ND-57.70 mg/L, and ND-188.21 mg/L in spices, respectively. The highest mean levels of benzoic acid, sorbic acid, and propionic acid were found in cinnamon (167.15 mg/L), basil leaves (22.79 mg/L), and white pepper (51.48 mg/L), respectively. The results in this study provide ranges of concentration regarding naturally occurring benzoic acid, sorbic acid, and propionic acid in spices. Moreover, the results may use to the case of consumer complaint or trade friction due to the inspection services of standard criteria for the preservatives of spices.

• Journal of Korea Port Economic Association
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• v.30 no.4
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• pp.69-89
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• 2014

The business performance of port industry is steadily getting worse due to international environmental regulation. The port industry should be prepared according to ambient condition change. IMO(International Maritime Organization) is tightening up environmental regulation of vessel and maritime industry field. ECA(Emission Control Area), starting with the Baltic, has initialized and has been expanded. Korea must strengthen the control of vessel in accordance with IMO's restriction, if Korea is designated as emission control area. These situations cause the expansion of LNG-fuelled ships. Add to the larger trend of ships, Korean government should be done a preemptive action against LNG bunkering industry. This study proposes the concept of floating offshore LNG bunkering system and is conducted its economic feasibility evaluation based on empirical analysis. We examine the theoretical foundation and basic information via "A Planning Study on the Engineering Development of Floating Offshore LNG Bunkering Terminal" in 2013 and we evaluate the business potential by using the report above mentioned. The results of this study are as follows. The values of B/C analysis are between 0.679 and 2.516 depending on market share and R&D contributiveness. In case of 10.9%(market share), if market share are 50% and 60%, the value of B/C analysis are 0.697 and 0.837 respectively. Except in two cases, all remaining values are over 1.0. Moreover, the research is conducted sensitivity analysis to remove the project uncertainty. In order to maintain economical validity, a project manager have to establish business strategies which are not to cause increase of expense and sustain market share and R&D contributiveness in the scenario with normal levels.

• Journal of Korea Technology Innovation Society
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• v.12 no.4
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• pp.788-818
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• 2009

Renewable energy refers to solar energy, biomass energy, hydrogen energy, wind power, fuel cell, coal liquefaction and vaporization, marine energy, waste energy, and liquidity fuel made out of byproduct of geothermal heat, hydrogen and coal; it excludes energy based on coal, oil, nuclear energy and natural gas. Developed countries have recognized the importance of these energies and thus have set the mid to long term plans to develop and commercialize the technology and supported them with drastic political and financial measures. Considering the growing recognition to the field, it is necessary to analysis up-to-now achievement of the government's related projects, in the standards of type of renewable energy, management of sectional goals, and its commercialization. Korean government is chiefly following suit the USA and British policies of developing and distributing renewable energy. However, unlike Japan which is in the lead role in solar rays industry, it still lacks in state-directed support, participation of enterprises and social recognition. The research regarding renewable energy has mainly examinedthe state of supply of each technology and suitability of specific region for applying the technology. The evaluation shows that the research has been focused on supply and demand of renewable as well as general energy and solution for the enhancement of supply capacity in certain area. However, in-depth study for commercialization and the increase of capacity in industry followed by development of the technology is still inadequate. 'Cost-benefit model for each energy source' is used in analysis of technology development of renewable energy and quantitative and macro economical effects of its commercialization in order to foresee following expand in related industries and increase in added value. First, Investment on the renewable energy technology development is in direct proportion both to the product and growth, but product shows slightly higher index under the same amount of R&D investment than growth. It indicates that advance in technology greatly influences the final product, the energy growth. Moreover, while R&D investment on renewable energy product as well as the government funds included in the investment have proportionate influence on the renewable energy growth, private investment in the total amount invested has reciprocal influence. This statistic shows that research and development is mainly driven by government funds rather than private investment. Finally, while R&D investment on renewable energy growth affects proportionately, government funds and private investment shows no direct relations, which indicates that the effects of research and development on renewable energy do not affect government funds or private investment. All of the results signify that although it is important to have government policy in technology development and commercialization, private investment and active participation of enterprises are the key to the success in the industry.