• KSBB Journal
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• v.26 no.3
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• pp.193-198
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• 2011

Polyester was prepared through the esterification reaction between watsepaper liquefied by ethylene glycol and carboxylic acid. Liquefaction was carried out at the previously determined condition of 100 minutes, $160^{\circ}C$, and 3% sulfuric acid, and the hydroxyl value of the liquefied product was 411 mg KOH/g. In order to remove bubbles produced during the curing step, the method to introduce a slight nitrogen stream into reaction vessel and/or the method to preheat a polyester film at $85^{\circ}C$ before curing step were used alone or in combination. But if curing temperature was $130^{\circ}C$, simple method to cure a film for 5 hours at $130^{\circ}C$ without using both methods was found to be most effective. The polyesters prepared with various carboxylic acids showed significant different physical properties, and maleic acid was best among them. Also, the effect of reaction time and temperature, C/H (carboxyl group/hydroxyl group) ratio, and type of additive on the crosslinkage of polyester was investigated. Lithium hydroxide or citric acid as additive was used to enhance the crosslinkage of polyester and citric acid was proved to be much more effective than lithium hydroxide. The effect of reaction temperature on the crosslinkage was marginal, but the crosslinkage decreased above $130^{\circ}C$. The crosslinkage was 86% when the polyester was prepared at an optimum condition such as $130^{\circ}C$ and 15 minutes of reaction condition, 1.5 of C/H ratio, $130^{\circ}C$ and 5 hours of curing condition, and 10% addition of citric acid.

• KSBB Journal
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• v.22 no.1
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• pp.43-47
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• 2007

The effect of surfactant on the hydrolysis of used newspaper was investigated. The most suitable surfactant for the pretreatment stage was found to be NP-series surfactants among 9 kinds of non ionic surfactants. Process parameters such as surfactant concentration, mixing speed, pretreatment temperature and time were tested to optimize for maximum digestibility and 0.5%, 100rpm, 30$^{\circ}C$, and 1 h were found to be optimum, respectively. In order to maximize digestibility, substrate was pretreated with NP-20 and then the pretreated substrate was hydrolyzed by adding TW-80. The effect of surfactant on the hydrolysis of previously surfactant-pretreated newspaper was marginal. Therefore, the digestibility with the addition order of enzyme and surfactant was investigated by using surfactant only in hydrolysis stage. The results show that digestibility was more lowered as the surfactant addition after adding enzyme to substrate was more delayed.

• International Commerce and Information Review
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• v.13 no.3
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• pp.301-323
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• 2011

There have been 20 cases of trade disputes related to zeroing in WTO. In these day, it was judged that the use of zeroing in the calculation of dumping margin is against ADA. Recently, WTO decided in favor of Korea in regards to Korea's stainless steel products on January, 2011. There finally was a high possibility of zeroing being changed. In December 2010, the American government announced it would revise zeroing system through an federal register. Many researchers, such as Linsey and Ikenson(2000), William W. Nye(2009) already clarified through empirical analysis that no use of zeroing leads to a large decline in the margin of dumping. If zeroing is abolished in the future, the margin of dumping imposed on Korea's stainless steel will drop sharply. According to this empirical study, the margin of dumping in 6 stainless steel among 12 products commodities subject to Anti Dumping regulation from US reduced below de-minimis or 3%. These stainless steel is likely to be excluded from the Anti Dumping regulation through review investigation and Korea's export of steel to America is expected to be increased steeply in the future.

• Microbiology and Biotechnology Letters
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• v.20 no.1
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• pp.14-19
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• 1992

The xylanase producing microorganisms occurring on rotten woods were selectively isolated on the modified Czapek-Dox medium supplemented with 0.5% xylan as a sole carbon source. Among more than three-hundred isolates of xylanase producing microorganisms, only two bacterial isolates were turned out to be more potent xylanase producer than the reference strain of xylanase producer, Aureobaszdium pullulans NRRL Y-2311. The exo-xylanase producer, bacterial isolate No. 33 was identified as a strain of Pseudomonas sp. on the basis of morphological and biochemical characterizations as well as cellular fatty acid composition. Optima of pH and of temperature for enzyme reactions of xylanase were 5.5 and $50^{\circ}C$ respectively. The enzyme was stable in a range of pH 5.0~7.0 and below $45^{\circ}C$. Among the number of carbohydrate substrates, xylose was turned out to be a potent inducer of Pseudomonas sp. No.33 exo-xylanase. Among the raw materials tested, rice straw was the best material for xylanase production by Pseudomonas sp. strain No. 33.

• Journal of the Korea Convergence Society
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• v.11 no.8
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• pp.173-182
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• 2020

The government continuously improves the RPS system to expand the supply of renewable energy, but there has been criticism that more environmental aspects should be considered to reduce GHG emission. REC weights are differentiated according to renewable energy sources. Greenhouse gas emission is one of the decisive factors, and its value is set by experts' opinion. This study assigns LCA to get accurate value of GHG emission. The LCA calculates emitted greenhouse gases from entire process of fuel production, transportation, power plant construction, operation, and decommission. This study suggests a method to change the greenhouse gas reduction effect from the existing qualitative method to the quantitative method and evaluates them. As a result, the evaluation score is changed, but the tier interval is so large that it does not affect the REC weight. Therefore, this study suggests the way that directly reflect the greenhouse gas reduction effect in the REC weight.

• The Journal of the Korea Contents Association
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• v.11 no.4
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• pp.164-176
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• 2011

To get an implication for desirable direction for Collaboration between Reporter & Producer, I found that had 4 modes of collaboration such as, Producer System, Reporter System, Double Reporting System, Co-Work System, and each was distinguished by field cover, on-mic, editing, writing. Producer system and Reporter system got no chemical synergy because of simple array of single reports due to physical assemble. The achievements of collaboration was birth of new news which had different duration, visual, sound & perspective. It also offered fertile soil for new program and genre literacy of 8 o'clock news. The success factor of collaboration was surprisingly turned out to be personnel rather than system. The balance of reporter & producer was also good factor. But the wall between 2 groups was so high that, after disappearance of extraordinary leader, system began to crumble and at last program was repealed.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.2 s.115
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• pp.52-60
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• 2006

Environment-friendly shock-absorbing materials were made of wastepaper such as Korean old corrugated containers(KOCC) and Korean old newsprint (KONP) with a vacuum forming method. The plate-like cushioning materials made of KOCC and KONP respectively by vacuum forming showed superior shock-absorbing properties with lower elastic moduli compared to expanded polystyrene (EPS) and pulp mold. Even though the plate-like materials had many free voids in their fiber structure, their apparent densities (${\approx}0.1g/cm^3$) were a little higher than that of EPS (${\approx}0.03g/cm^3$) and much lower than that of pulp mold(${\approx}0.3g/cm^3$). However, the elastic moduli of the cushioning materials made of wastepaper were much lower than that of EPS or pulp mold. This finding implies that the cushioning materials made of KOCC fibers containing more lignin than KONP show better shock-absorbing properties than KONP. Moreover, the cushioning materials made of KOCC and KONP respectively showed greater porosity than pulp mold. The addition of cationic starch to the cushioning materials contributed to the increase in the elastic modulus to the same level as that of EPS. Furthermore, the deterioration in fiber quality by repeated use of wastepaper played a positive role in improving shock-absorbing ability.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.4
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• pp.82-90
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• 2009

It is very important to utilize effectively fibrous waste paper in terms of cost savings, environmental effects, and governmental policies. The quality of final products and runnability of papermaking process are primarily affected by constitutions of fibrous raw materials. In specific, board grade paper depends directly on compositions of waste paper bales. At present, the raw materials of board grade paper are mainly derived from lots kinds of wastepaper. Some papermaking countries, like EU, USA and Japan have advanced classification and management systems of recycled fiber, but Korea has not yet organized systematically. In this study, evaluation of wastepaper bale compositions and their fiber properties were carried out for effective utilization of fibrous raw materials for board grade paper production. 3 kinds of wastepaper bales were classified to fibrous or non-fibrous materials. In case of fibrous materials, KOCC, kraft sack paper and white duplex board matters were main component in total weight basis, and in case of non-fibrous materials, vinyl, plastic and cloth matters were main component, in turns. 3 representative kinds of waste paper were disintegrated and classified, and then prepared to handsheet for evaluation of recycled fiber property. Consequently, fines and ash content of waste paper, isolated from KOCC and white duplex board were higher than that of kraft sack paper. pH values of all kinds of waste fibers were neutral or weak alkaline.

• Journal of Engineering Education Research
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• v.12 no.4
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• pp.93-101
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• 2009

Many engineering professors are forced to execute ABEEK activities. Engineering professors are evaluated by their educational, research and service activities, but are mainly by their research papers published in professional journals. The gap between the duties and the evaluation criteria exists among engineering professors. This paper deals with the possible ways of including the ABEEK activities in the engineering professor evaluation system. Among the five ways suggested for a simple survey, tenured professors prefer to reduce the lecture time but junior professors prefer to reduce the research burden for the benefit from executing ABEEK activities. Based on logical reasoning and the preference among the surveyed professors, ABEEK related activities may be included in the educational part for the professor evaluation system before the ABEEK system is matured. However, ABEEK related activities have to be converted to the duties of engineering professors in the long run as in the US universities.

• Proceedings of KOSOMES biannual meeting
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• 2006.05a
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• pp.53-58
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• 2006

Recently, vessel's average speed in the sea becomes fast because of the increasing of high-speeds vessel like a container ship and ferry. So, it is considered that speed control in the korean narrow waterway isn't the proper vessel traffic management, now. And, there is a rare paper studied about speed control quantitatively and numerically, especially speed control is discussing continuously, as abrogation of Incheon Port's speed control and alleviation of Kwangyang Port's speed control a according to navigating mariner's request. After this paper replayed the navigation traffic flow in the straight waterway using marine traffic flow simulation, the Environmental Stress Model is introduced to evaluate difficulty of each vessel's traffic.