• Journal of the Korean Wood Science and Technology
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• 제20권3호
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• pp.11-20
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• 1992

Steam explosion is one of the most effective pretreatment for fractionating wood. This leads to the total utilization of wood basic components; cellulose, hemicellulose and lignin. The amount of sugar and lignin extracted with the hot water method was very low. The lignin content of residues after extraction with using a sodium hydroxide treatment, increased delignification of carbohydrate as the concentration of alkali was increased. Oak, pretreated with steam exploded at 25kg/$cm^2$ for 6 min. then 1% alkali for 2hrs. showed a delignification rate up to 95%. A sodium chlorite treatment of steam exploded pine and oak also afforded a high deligninfication effect. Pine, treated 10% sodium chlorite for 2hrs. showed high delignification. However, by using a sodium hydroxide treatment, a 2% retreatment for Ihr. after a 2% for 2hrs. afforded remarkable delignification effect on exploded wood at 30kg/$cm^2$ for 9min. and at 35kg/$cm^2$ for 3-6min. In oak, an initial 2hrs. treatment of 2% sodium chlorite was followed by a second 2hrs. treatment at 10%. This showed a delignification rate of 96%.

• 한국건설관리학회논문집
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• 제11권2호
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• pp.15-24
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• 2010

건설 사업관리의 자료 수집 및 분석에 있어 아직도 많은 부분이 현장관리자의 수작업에 의존하고 있다. 이런 수작업에 의한 관리 방법의 대표적인 문제점으로서는, 자세한 현장자료의 획득이 어려울 뿐만 아니라, 가능하더라도 이를 위해서는 상당한 비용과 노력이 소요된다. 따라서 효율적인 사업관리를 위한 첨단 DAT(Data Acquisition Technology) 기술이 적용을 통한 자료수집 자동화가 시도되고 있으나, 대부분 기존 연구가 단일 공종이나 혹은 일부 주요 관리만을 대상으로 한 DAT 적용 연구로 이루어져 프로젝트 전체관점에서 분석한 종합적 연구는 전무한 상태이다. 따라서 본 연구는 DAT를 건설 사업관리와 관련하여 포괄적으로 분석함으로써 활용분야를 살펴보고 대체 활용 방향을 제안한다.

• 대한안전경영과학회지
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• 제11권2호
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• pp.167-178
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• 2009

De facto standards can be divided into the U.S. group standards' and 'forum and the consortium standard. mainly applies to high-tech industry forums, and a consortium standard of the industry given the nature of the standard are frequently revised, the country Due to the introduction of standard time. Economic loss to consider when in reality, the introduction of national standards of the United States is limited to the desirable standard, and the fact the actual award of standards, national standards, or if you want to introduce standard, each of depending on the type of attitude and strategy for standards by category, based on the characteristics of each body strategy and are needed. Through this study on utilization of de facto standards for national standards, it is researched that major de facto standards bodies status and domestic industrial fields which need utilization of de facto standards for national standards. Through overseas Case, effective usage of de facto standards will be obtained.

• 한국환경과학회지
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• 제11권12호
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• pp.1267-1274
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• 2002

This study was carried out to evaluate the pollutant removal efficiencies of the advanced drinking water treatment using ozonation process. For raw water, Nakdong River was used. By conducting batch test of ozonation, the following results were obtained. When ozone dosage of $5 mg/{\ell}$ was used, ozone transfer and utilization efficiencies of the ozonation were 94 to 92%, respectively. Removal efficiencies of single VOC compound or mixed VOC compounds in the raw water were 80% to 90% by the ozonation with $2 mg/{\ell}$ dosage and 10 minutes contact time. Removal efficiencies of ABS by the ozonation with $1 mg/{\ell}$, $3 mg/{\ell}$ dosage and 20 minutes contact time were 83% to 96%, respectively. Almost 67% of chlorophyll-a at the concentration of $38.4\mu\textrm{g}/{\ell}$ was removed by ozonation at ozone dosage of $1 mg/{\ell}$ for 20 min. Considering the efficiency of ozone utilization and water treatment, the most effective ozonation could be obtained with high ozone dosage and short contact time.

• 한국입자에어로졸학회지
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• 제15권4호
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• pp.183-190
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• 2019

Here, we introduce porous graphene balls (PGB) showing superior electrochemical properties as supercapacitor electrode materials. PGB was fabricated via activation of graphene oxides (GO) by H₂O₂ and aerosol spray drying in series. Effect of activation on the morphology, specific surface area, pore volume, and electrochemical properties were investigated. As-prepared PGB showed spherical morphology containing pores, which lead to the effective prevention of restacking in graphene sheets. It also exhibited a large surface area, unique porous structures, and high electrical conductivity. The electrochemical properties of the PGB as electrode materials of supercapacitor are investigated by using aqueous KOH under symmetric two-electrode system. The highest specific capacitance of PGB was 279 F/g at 0.1 A/g. In addition, the high rate capability (93.8% retention) and long-term cycling stability (92.2%) of the PGB were found due to the facilitated ion mobility between the porous graphene layers.

• Asian-Australasian Journal of Animal Sciences
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• 제10권1호
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• pp.15-19
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• 1997

An experiment was conducted to clarify the effects of dietary supplementation of monensin or salinomycin on mineral utilization of growing goats. Six goats weighing 10.54 kg initially were randomly assigned to treatments in a replicated $3{\times}3$ Latin square design. Treatments were a basal diet, basal plus 30 ppm monensin and basal plus 20 ppm salinomycin on a DM basis. The basal diet was a mixture of Italian ryegrass wafer, soybean meal, ground maize and $CaCO_3$ with DM proportions of 50, 13.76, 36 and 0.24%, respectively. Each period lasted for 21 days, and the apparent absorption and retention of minerals were measured during the last 7 days of each period. Salinomycin supplementation improved NDF digestibility and plasma glucose. The apparent absorption and retention of Ca, P, Mg, Na and K were not influenced by the treatments. The concentrations of plasma Ca, P, Mg, Na, K and Cl were similar in all treatments. The ionophore supplementation had no significant effect on acid excretion. The results suggest that 30 ppm monensin or 20 ppm salinomycin supplementation is not effective in improving the utilization of Ca, P, Mg, Na and K in growing goats fed a diet composed of the 50% concentrate.

• 한국식생활문화학회지
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• 제17권5호
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• pp.605-618
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• 2002

The purposes of this research were to; (a) identify useful information source; (b) assess the usefulness of the Internet as an information source; and (c) assess the degree of Internet utilization for purchasing process in food service industry. The results were as follows; 1. 'personal experience and colleague recommendation' was perceived as the most useful information source, whereas the most frequently used source was 'Internet web site' for real purchasing practice. 2. the most frequently used purchasing activity through Internet was 'online ordering', followed by 'gathering product/component information', however e-marketplace or Internet bidding were less performed by Internet. 3. acquisition of real time information, rapidity, accuracy, and increasing effectiveness of purchasing process were reported the advantages of Internet utilization. 4. respondents somewhat or strongly agreed with the importance of Internet in terms of present and future purchasing management. The results of the research suggest that Internet should be able to improve purchasing process and enhance buyer-supplier relationship directly or indirectly, therefore food service industry should consider making attempt to new purchasing systems through Internet for strategic sourcing and effective procurement management.

• 한국환경교육학회지:환경교육
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• 제19권3호
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• pp.165-182
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• 2006

Demands for developing diverse teaching methods and materials which can lead to active participation of students in classes have been emerged for environmental education in secondary schools. In order for more effective environmental education, a variety of programs in the mass media including public broadcasting have been used. Advantages associated with the broadcasted TV programs include compensation of temporal and spatial limits embedded with the printing media, improvement of studying efficiency, and provision of diverse studying opportunities, leading to the promotion of the awareness of environmental issues. In this study, 256 environmental issues related TV programs being aired via major public broadcasting companies such as EBS, KBS, MBC and SBS between years of 2003 and 2004 were analyzed. During the present research, selection of the programs was made based on the weight of the environmental issues in independent programs being aired for at least 10 minutes. A survey as a primary means was carried out for the utilization of the audio-visual educational materials in order to provide a new method employing the TV programs which were related to the environmental issues during the instruction in secondary schools.

• 소성∙가공
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• 제19권6호
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• pp.329-336
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• 2010

Ring forging process is more appropriate for high-length and thin walled ring, because it utilizes the forging press and hence does not require heavy-duty ring rolling mill. Although ring forging process is very simple and economic for facilities, the process is not efficient because of multi-forging-step and low material utilization. An effective ring forging process is developed using a hollow ingot. When a hollow ingot is used with a workpiece, the ingot can be forged into a final ring without multi-stage pre-forging process, such as, cogging, upsetting, and piercing, etc.. Finally it has advantages of the material utilization and process improvement because a few reheating and forging process are not necessary to make workpiece for ring forging. The important design variables are the applied plastic deformation energy to eliminate cast structure and make uniform properties. In this study, the mechanical properties after forging of hollow cast ingot were investigated from the experiment using circumferential sectional model. Also, the effects of process variables were studied by FEM simulation on the basis of thermo-visco-plastic constitutive equation. Applied strain is different at each position in length direction because diameter of hollow ingot is different in length direction. The different strain distribution become into a narrow gap by additional plastic deformation during diameter extension process.

• 한국농공학회지
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• 제29권2호
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• pp.30-38
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• 1987

Because the development of Korea's water resources will reach its limit in the near future, preparations should now be begun to deal with problems that may come as a result. It will be too late to start preparations when the water resources have already reach their limitation and, as the preparations cannot be done in a day, it will take a long time to provide them. Now is the great turning point to accumulate our technical experiences and attain our plans gradually. The preparations against this are summarized as follows; 1)The transitory use of water should be turn into the recurrent use for the future. 2)A cooperative water control system of an area should be arranged. 3)Water saving, control of water demand, and the multiple use of water should be encouraged. To do this effectively, people should be informed of the value and rarity of water. 4)The development of freshwater reserviors at estuaries is closely related to the development of water utilization in the whole river basin. The development of water resources by the construction of freshwater reservoirs at the estuaries should be started, when the development of upstream water resources reaches their limitation. 5)The existing water utilization structures should be reorganized by water resources exchange planning, so the effective use of water in large areas be attained.