• Journal of Environmental Health Sciences
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• v.28 no.2
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• pp.23-39
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• 2002

This study focuses on the structure of geographical conditions, the riverbed, the meterological and atmospheric examination, the ecological environment, the food chain and the ecosystem, in order to establish a basic plan for preparing a natural learning area of environmental ecosystem in Bukchun and its surroundings, Gyeongju. The results could be summarized as follows. Bukchun is a first grade which extends 6km along the road from Bomun bridge to the junction of Hyungsangang. The basin area is 7.10$\textrm{km}^2$ and the slope is 1/200~1/300. Gyeongju has good atmospheric conditions, i.e. SO$_2$0.011 ~0.017ppm, CO 0.8~ 1.5ppm, NO$_2$0.013~0.019ppm, $O_3$0.013~0.020ppm, TSP 85~142$\mu\textrm{g}$/㎥, PM-10 47~90$\mu\textrm{g}$/㎥ and Pb 0.057 ~0.129$\mu\textrm{g}$/㎥, which is below the annual and daily averages, and is little lower than those of Pohang and Ulsan. The ecosystem of Bukchun is based on the structure of the food chain, which includes birds such as the grey and white herons at the top of the food chain. This study also considers the development of the river's in terms of culture, environment and ecology concept.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.159.1-159.1
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• 2014

We report a simple method for preparing hydrophobic mesoporous silica and its use as a pre-concentrating agent of gas analytes. Hydrophobic mesoporous silica was prepared by coating PDMS (polydimethylsiloxane) thin layer on commercial mesoporous silica with thermal deposition method in a sealed chamber. By using this method, we were able to coat PDMS layer on inner-walls of pores larger than 15 nm. Also, contact angle measured on a surface consisting of PDMS-coated mesoporous silica exceeded $150^{\circ}$, implying that the surface has high water repellency. Pre-concentration ability of PDMS-coated mesoporous silica and baremesoporous silica was tested under dry and humid conditions. Adsorption and molecular desorption of gas analytes was much enhanced by PDMS-coating on mesoporous silica under both dry and humid conditions. Therefore we suggest that PDMS-coated mesoporous silica can be an efficient pre-concentration agent in order to enhance sensitivity of various detectors.

• Journal of Environmental Health Sciences
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• v.28 no.2
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• pp.11-22
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• 2002

This study analyzes the river system and water quality conditions of Bukchun in order to establish a basic plan for Preparing a natural learning and experimental area of environmental ecosystem in Bukchun, Gyeongju. It also tries to establish an integrated plan for water management of Bukchun stream based on water contaminants. In addition, after analysing the water quality at 13 points during the non-rainy season, the effluent of municipal wastewater was of relatively better quality with I ~ II grade, below the water quality standard of the river, except in points near Samsung apartments. However, analysing the Hyeongsangang and the effluent of Bomunho and Duckdongdam in rainy season, the water quality was II ~ III grade according to environmental standard. The water Quality of those samples was strongly dependent of non-point source.

• Journal of the Korean Society for information Management
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• v.34 no.1
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• pp.263-289
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• 2017

The purpose of this study is to enhance the understanding of the provisions for library exceptions in copyright laws and to suggest the direction for the revision of provision in the Copyright Act of Korea. This study compares and analyzes the provisions for library exceptions in several countries' copyright law including Korea, Japan, UK, Australia and USA. This study found that the most common issues in library exception provisions are providing reproduction for users, reproduction for preservation, reproduction for interlibrary loan and digitization of library collections but the conditions for each issue are quite different. The suggestions for the revision of the library exceptions in the Copyright Act of Korea are as follows: changing the amount of reproduction of unpublished works, of works which cannot be obtained at a fair price and of periodicals for users, the transmitting digital reproduction to the user under limited conditions, preparing conditions for reproduction for preservation in libraries, preparing the applicable provisions for reproductions for interlibrary loans and for the limitation of works to be digitized and extending their use at the same time.

• Journal of the Korean Physical Society
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• v.73 no.9
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• pp.1340-1345
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• 2018

Mo-10 at.% Cu nanocomposite powders were fabricated by using planetary ball-milling (PBM), a mechanical alloying technique for preparing nanocomposite alloy powders of metals with mutual insolubility, and the variations in the physical and the chemical characteristics with the process conditions were investigated. We observed that Mo-10 at.% Cu was an appropriate composition to ensure a good alloying grade and minimal welding between particles. The influences of the temperature and the milling conditions on the mechanical alloying process and the phase change of Mo-10 at.% Cu composite powders were investigated, and the particle and the grain sizes of the powders after mechanical alloying were confirmed. The Mo-10 at.% Cu powders showed homogeneous elemental distributions and no phase changes up to $1200^{\circ}C$; their compositions were retained after the mechanical alloying process. The finest grain size obtained was about 5 nm for powders processed using optimum PBM processing conditions: ball-to-powder weight ratio of 5 : 1, ambient air atmosphere, a milling time of 20 h, a rotation speed of 200 rpm, and a stearic acid content of 4 wt.% produced superfine-grained Mo-10 at.% Cu nanocomposite powders with an average grain size of 5 nm (which is smaller than that of other similar materials reported in the literature). The analytical results confirmed that the PBM technique presented here is a promising method for preparing superfine-grained Mo-10 at.% Cu powders with improved properties.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.697-702
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• 1995

Changes of physicochemical properties during the preparation of persimmon pickles and its optimal preparing conditions including salt concentration, soaking temperature, soaking time, amount of fermented soy paste, and ripeness of fresh pesimmon were investigated. The salinity and pH of soaking solution were rapidly dropped during 40 days of soaking, while their changes were negligible after 40 days of soaking. When the fermented soy paste was added to the soaking solution with $10{\sim}40%$ the pH dropped more slowly. Salt content in persimmon pickles was gradually increased during soaking and soluble tannin content was rapidly decreased during the first 10 days of soaking. L value of persimmon pickles was gradually decreased, but a/b value was slightly increased. The hardness of persimmon pickles was slightly increased up to the 20th day of soaking and then decreased. Most acceptable persimmon pickles were prepared when the less ripened fresh persimmons were soaked in 10% salt solution at $15^{\circ}C$ for 40 days, and the suitable amount of soy paste added to the soaking solution for preparing persimmon pickles was 20%.

• Journal of Pharmaceutical Investigation
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• v.15 no.2
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• pp.83-90
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• 1985

The effects and the optimum manufacturing conditions for the preparation of synthetic aluminum silicate which has acid-consuming power and adsorbing capacity were investigated. The results are as follows: 1. The adsorbing capacity was affected by the mixing order of the reactants, that is, the excellent ones were obtained by the method which add the sodium silicate solution to the potassium alum solution. 2. Even though preparing by the bane manufacturing condition, the acid-consuming power is superior to the adsorbing capacity. 3. According to the Box-Wilson Plan, the optimum reaction conditions are concentration of sodium silicate solution; 38% w/w, settling time; 43 hours at room temperature, drying time; 13 hours at $110^{\circ}C$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.1
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• pp.36-43
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• 2015

We examined sensory characteristics to determine the optimal conditions for flounder Verasper moseri Jordan et Gilbert sikhe preparation, using response surface methodology. Our aim was to develop the optimum mixing rates and materials for producing highly palatable flounder sikhe. The optimal fermentation temperature, salt concentration, and fermentation period for preparing flounder sikhe of acceptable quality were $11.63^{\circ}C$, 4.66% and 9.12 days, respectively. The optimal percentages of red pepper powder, garlic, monosodium glutamate, ginger, radish and foxtail millet were 16.08%, 7.21%, 2.96%, 3.70%, 10.12% and 13.72% respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.6
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• pp.627-634
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• 2012

Squid Sikhae is traditional salt-fermented food in Korea. We evaluated the standardization of optimal processing conditions for desirable quality-controlled squid Sikhae using analyses of physiochemical properties, microbiological species, and organoleptic tests. Among several squid Sikhae preparation processes, the optimal fermentation temperature sun-dried sea salt concentration, and fermentation period for squid Sikhae of acceptable quality were $10^{\circ}C$, 4%, and 6 days, respectively. Amino-N and volatile basic nitrogen (VBN) contents of the acceptable quality squid Sikhae were 162.51 mg/100 g and 15.25 mg/100 g, respectively.

• Transactions on Electrical and Electronic Materials
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• v.5 no.1
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• pp.11-14
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• 2004

An rf triode magnetron sputtering system is designed and installed its construction in vacuum chamber. In order to calibrate the rf triode magnetron sputtering for thin films deposition processes, the effects of different glow discharge conditions were investigated in terms of the deposition rate measurements. The basic parameters for calibrating experiment in this sputtering system are rf power input, gas pressure, plasma current, and target-to-substrate distance. Because a knowledge of the deposition rate is necessary to control film thickness and to evaluate optimal conditions which are an important consideration in preparing better thin films, the deposition rates of copper as a testing material under the various sputtering conditions are investigated. Furthermore, a triode sputtering system designed in our team is simulated by the SIMION program. As a result, it is sure that the simulation of electron trajectories in the sputtering system is confined directly above the target surface by the force of E${\times}$B field. Finally, some teats with the above 4 different sputtering conditions demonstrate that the deposition rate of rf triode magnetron sputtering is relatively higher than that of the conventional sputtering system. This means that the higher deposition rate is probably caused by a high ion density in the triode and magnetron system. The erosion area of target surface bombarded by Ar ion is sputtered widely on the whole target except on both magnet sides. Therefore, the designed rf triode magnetron sputtering is a powerful deposition system.