• Journal of the Korean Chemical Society
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• v.32 no.6
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• pp.593-602
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• 1988

Polymer-supported crown ethers (Ps-CE) which can be used for phase-transfer catalyst (PTC) were synthesized for the purpose of allowing reusable function to ordinary crown ethers, and the kinetics of the liquid-solid-liquid triphase-catalyzed nucleophilic displacement reaction of iodide (aqueous phase) on 1-bromooctane (organic phase) using synthesized Ps-CE (solid) were studied. Ps-CE were obtained by grafting of hydroxymethyl crown ethers to 1~2% cross-linked chloromethylated polystyrene. All reactions followed a pseudo-first order dependency on the 1-bromooctane concentration and the observed rate constants $(k_{obsd})$ were linearly related to the molar equivalents of Ps-CE, and were subjected to the influence of cross-linking density of polymer backbone, solvent and the reaction temperature. The catalytic activity of Ps-CE was also compared with that of structurally similar soluble crown ethers, and used Ps-CE were easily recovered after the reaction by simple filtration and could be reused without loss of catalytic activity in the same anionic displacement reaction. Enthalpies and entropies of activation associated with the displacement were 10~20kcal $mol^{-1}, 20~55eu. respectively, and the free energy of activation was ~30kcal mol^{-1}$.

• Journal of Korea Port Economic Association
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• v.35 no.4
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• pp.187-206
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• 2019

After reviewing the concept and previous studies related to green ports, this study analyzes the implications of green port policy of advanced ports in foreign countries and analyzes problems in terms of environmentally-friendly green port policy for Ulsan port, and to present sustainable green logistics establishment measures. The literature survey and Benchmarking methods are adopted as research methodology and the results are as follows. First, the pan-government climate change response management system, legislation of relevant laws, implementation of fiscal support policies, and roadmaps should be established. Second, the foundation for eco-friendly green growth should be established through the discovery of business models in conjunction with leading industries in the Southeastern Metropolitan Economic Area. Third, the Ulsan Port Greenport, such as AMP, in-port LNG propulsion ship, and ESI vessel incentive, should be built. Fourth, a low-carbon, high-efficiency sea-shuttle service shall be established through the introduction of the sea-shuttle service along the sea route. Fifth, energy self-reliant ports, including all institutions in the metropolitan Ulsan port area that have exceeded the level of Ulsan port Authority, should be built. Finally, water-type ports need to be built through the creation of coastal forests, the purification of marine water quality, and the introduction of colors to port.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.3
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• pp.304-311
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• 2014

In this study, to apply hydrogen energy to ship engine and to generate effective hydrogen production, we investigated the effects of high temperature $H_2SO_4$ feed rate and cooling water rate to pump parts with fixed frequency needed to reciprocate motion and a simulation was conducted at each condition. In the fixed frequency and cooling water inlet flow rate of 0.5 Hz and 3.9 kg/s, we changed the high temperature $H_2SO_4$ flow rate to 47.46 kg/s (it is 105 % of 45.2 kg/s), 49.72 kg/s (110 %), and 51.98 kg/s (115 %). Also, at 0.5 Hz and 45.2 kg/s of frequency and high temperature $H_2SO_4$ flow, the thermal hydraulic analysis was performed at the condition of 95 % (3.705 kg/s), 90 % (3.51 kg/s), and 85 % (3.315 kg/s). In overall simulation cases, the physical properties of materials are more influential to the temperature increase in the pump part rather than the changes on the feed rate of high temperature $H_2SO_4$ and cooling water. A continuous operation of pump was also capable even if the excess feed of high temperature $H_2SO_4$ of about 15 % or the less feed of cooling water of about 15 % were performed, respectively. When the increasing feed of high temperature $H_2SO_4$ of up to 5 %, 10 %, and 15 % were compared with base flow (45.2 kg/s), the deviation of time period rose to a certain temperature and ranged from 0 to 4.5 s in the same position (same material). In case of cooling water, the deviation of time period rose to a certain temperature and ranged from 0 to 5.9 s according to the decreasing feed changes of cooling water at 5 %, 10 %, and 15 % compared to a base flow (3.9 kg/s). Finally, the additional researches related to the two different materials (Teflon and STS for Pitch and End-plate), which are concerned about the effects of temperature changes to the parts contacting different materials, are needed, and we have a plan to conduct a follow-up study.

• Hwankyungkyoyuk
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• v.11 no.2
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• pp.130-143
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• 1998

This study was conducted as a preliminary step to establish a model for the practical application of environmental education related to food wastes collected from elementary school foodservices. Methods of treatment and present recycling status of food wastes in elementary schools in Kyonggido were surveyed. The consciousness of dieticians who have been serving for elementary school foodservices was also analyzed through the survey questions concerning environmental education for the reduction and recycling of food wastes. The results derived from this survey were as follows: The major portion of food wastes from elementary school foodservices was constituted with vegetables and soup, and an average amount of food wastes per day was highest in June and July. Therefore environmental education related to reduction of wastes was needed in the first semester of school terms, and the possible reduction of food wastes achieved through the proper planning of school foodservice menu was also needed. In most cases food wastes were collected and treated by animal growing farmers or composted by machines in school. In operating composting machines microorganism inoculant was mostly used but dieticians pointed out the problem of a nasty odor, insects, and high energy consumption. This situation means it has not been operated efficiently and suggests an efficiency problem of machine composting in elementary schools because composting itself is based on the aerobic digestion and high temperature fermentation which kills insects and harmful microorganisms. Elementary school dieticians in Kyonggido were aware that food wastes cause main pollution problem, and that food wastes are valuable resources which can be recycled, and recycling of food wastes is inevitable. But more than half of the schools surveyed have not been reused food wastes in school, so a proper model for recycling and reuse of food wastes in school grounds was thought to be needed. Environmental education programs related to food wastes have not been peformed in more than half of the schools surveyed. It was concluded that the following three plans will be helpful to reduce school food wastes. First, environmental education should be enforced, second, teachers' and dieticians' intensive teaching concerning food wastes should be needed, and finally establishment of a model for recycling and reuse of food wastes in school grounds and its application to environmental education would offer a valuable field experience to school students.

• Journal of the Korean Society for Railway
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• v.19 no.1
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• pp.38-45
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• 2016

The power transformation system of High Speed rolling stocks like KTX-Sancheon has shown excellent control capacities in the areas of riding comfortability, switching efficiency, safety and energy consumption due to technical developments in power-electronics, high speed & large scale integrated semiconductors and microprocessors. However, harmonics from IGBT, a high speed switching device used in the Convertor & Invertor equipment of rolling stocks have given rise to various problems in transformer substations, signaling systems, data transmission systems and facility monitoring systems. Especially, TI21 non-insulated track circuits have malfunctioned due to the influence of returning current harmonics which were generated at around of integer times of the number of power transformation equipment in the frequency domain. This paper, measures and analyzes various schemes to analyze the traveling path of the returning current harmonics generated due to the relationship between the rolling stocks and track circuits on site. Ultimately, theseschemes will be used to design high speed rolling stocks, AF track circuits and a common grounding network.

• Journal of Digital Convergence
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• v.14 no.8
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• pp.37-46
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• 2016

Patent application as achievements from R&D institutions in public sector have quantitatively increased by expanding R&D investment for enhancing competitiveness but there have been few tangible outputs from the investment. From this reason, TLO(Technology Transfer&Licensing Organization) and its operation becomes more important to implement technology transfer and commercialization and to bring success in the related business. To get work done more efficiently and to improve utilizing products of the R&D in the TLO, this research is to draw domains and activities of TLO and establish its task systems by prioritizing activities. From literature reviews and expert interviews, we generated 6 work domains and 21 task items. Applying AHP analysis, we discriminated the relative importance from task items and analyzed its priority. The finding of this research can provide implications for TLO to increase work efficiency and improve its performance.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.6
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• pp.1056-1062
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• 2008

To evaluate the effect of irradiation on restructured pork jerky containing paprika and Japanese apricot extracts, the quality of protein was determined in vitro based on the formation of trypsin indigestible substrate inhibitor (TIS) and the computed protein efficiency ratio (C-PER) as determined based on the protein digestibility and amino acid analysis. In addition, we compared the effects of electron beam irradiation to those of gamma irradiation. Approximately 3% of the moisture content of pork jerky was reduced in response to irradiation with 3kGy administered using an electron beam however, no additional reduction was observed in samples that were subjected to higher doses of irradiation. In addition, there were no notable differences in the crude protein and fat content of pork jerky samples that were subjected to irradiation, regardless of dose. Furthermore, the total amino acids profiles did not change in response to electron beam irradiation. However, the in vitro protein digestibility increased by 7% in response to 3kGy of electron beam irradiation and 5kGy of gamma irradiation, but no significant changes in digestibility were not observed in response to treatment with higher doses. TIS quantified as trypsin inhibitors were formed in response to irradiation using the electron beam (3kGy) and gamma rays (5kGy), although there was a slight reduction in the production of TIS inhibitors in samples irradiated with higher doses. Moreover, only samples irradiated with 10kGy (electron beam and gamma ray) showed higher TBA values than those of the control samples. Finally, the C-PERs $(2.50{\sim}2.60)$ were greater in all of the irradiated pork jerky samples than in the control samples (2.22). Taken together, these results suggest that electron beam irradiation and the incorporation of extracts (paprika and Japanese apricot) may be useful methods of improving the nutritional quality of pork jerky.

• Clean Technology
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• v.21 no.4
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• pp.271-277
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• 2015

A photocatalyst which mixed by the commercialized P25-TiO₂ and a synthesized Ag_xO was used in an appropriate weight ratio to effectively produce hydrogen gas in this study. The Ag_xOs were synthesized with the conventional sol-gel method, and tetramethylammonium hydroxides were added at the synthesis process in order to stabilize the solutions, and then the solutions were heat-treated at the temperatures of -5, 25, and 50 ℃, resulted to obtain the three types of silver oxides. Physicochemical properties of the synthesized Ag_xOs were identified through X-ray diffraction analysis (XRD), scanning emission microscopy (SEM), ultraviolet-visible spectroscopy, and X-ray photoelectron spectroscopy (XPS). In the photolysis results of water/methanol (weight ratio 1:1) solution, the mixture of P25-TiO₂/Ag_xO exhibited a significantly higher hydrogen gases evolution, compared to that of pure P25-TiO₂. Additionally, the addition of H₂O₂ as an supplement oxidant and in Ag_xO synthesized at 50 ℃ improved the hydrogen production efficiency. In particular, the emitted hydrogen gases reached to 13,000 μmol during 8 hours when a mixed catalyst, Ag_xO of 0.1 g and P25-TiO₂ of 0.9 g, were used.

• Clean Technology
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• v.23 no.2
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• pp.188-195
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• 2017

This research studied the adsorption of basic dye, Basic Blue 3 (BB3) by using coal-based granular activated carbon (C-GAC) from aqueous solution. All experiments were performed in batch processes, and adsorption parameters such as C-GAC dosage, contact time, initial dye concentration and temperature were evaluated. The removal efficiency of BB3 was increased with increasing the C-GAC dosage and 100% of initial concentration, $50mg\;L^{-1}$ was removed above 0.2 g of C-GAC. Also, the time to reach equilibrium depended on the initial dye concentration. According to the Langmuir model, the maximum uptakes of C-GAC were calculated to be 66.45, 84.97 and $87.19mg\;g^{-1}$ at 25, 35 and $45^{\circ}C$, respectively. In addition, thermodynamic parameters such as Gibbs free energy change, enthalpy change and entropy change were investigated.

• Polymer(Korea)
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• v.31 no.3
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• pp.215-220
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• 2007

The control of the surface energy by electrohydrodynamic force provides electrospraying with various potential advantages such as simple particle size control, mono-dispersity, high recovery, and mild processing conditions. The advantages are quite helpful to improve the stability of protein drug and control its release. Herein, the nano-encapsulation of protein drugs using electrospraying was investigated. Albumin as a model protein was processed using uniaxial and co-axial electrospraying, and chitosan, polycaporlactone (PCL), and poly (ethylene glycol) (PEG) were used as encapsulation materials. The major processing parameters such as the conductivity of spraying liquids, flow rate, the distance of electrical potential gradient, etc were measured to obtain the maximum efficiency. In the chitosan systems, mean particles size decreases as flow rate and the distance between nozzle and the collecting part decreases. In the uniaxial technique of the PCL systems, mean particles size decreases as flow rate decreases. In the coaxial technique of the PCL systems, it was found that the particles size gets larger under the application of the higher ratio of inner-to-outer liquid flow rates. The primary particles formed out of an electrospraying nozzle showed narrow particle size distribution, but once they arrived to the collecting part, aggregation behavior was observed obviously. Efficient nano-encapsulation of albumin with PCL, PEG, and chitosan was conveniently achieved using electrospraying at above 12 kV.