• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.269-275
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• 2015

The adsorption characteristics of ions were evaluated for the nitrate-selective carbon electrode (NSCE) in accordance with power supply methods. The NSCE was fabricated by coating the surface of a carbon electrode with anion-exchange resin powders with high selectivity for the nitrate ion. Capacitive deionization (CDI) experiments were performed on a mixed solution of nitrate and chloride ion in constant voltage (CV) and constant current (CC) modes. The number of total adsorbed ions in CV mode was 15% greater than that in CC mode. The mole fraction of adsorbed nitrate ion showed the maximum 58%, though the mole fraction was 26% in the mixed solution. This indicates that the fabricated NSCE is highly effective for the selective adsorption of nitrate ions. The mole fraction of adsorbed nitrate was nearly constant value of 55-58% during the adsorption period in CC mode. In the case of CV mode, however, the values increased from the initial 30% to 58% at the end of adsorption. We confirmed that the current supplied to cell is important factor to determine the selective removal of nitrate.

• Journal of Digital Convergence
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• v.13 no.9
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• pp.225-233
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• 2015

The convergence social app manufacturing platform for both demander and developer in worldwide provides a collective collaborative development approach. This platform can bring enhanced productivity with exchange of views among participants. If the assessment is not fair that many participants will leave the collective collaborative project. The previous studies verified the reliability of the evaluation based on statistical techniques. Because the previous studies did not consider the task performance of participants, do not reflect the feature of project tasks. So, the contribution scores of the participants can be distorted. In this study, we suggest the method for evaluating the development contributions value. This is considered the task performance of participants and involved the method of equitable and consistency peer assessment.

• Journal of the Korean Magnetics Society
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• v.19 no.3
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• pp.81-84
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• 2009

We examine the effect of U term (U = 3 eV) describing the Coulomb interactions between electrons on the results of electronic band structure calculations carried out for bcc Fe bulk, monolayer, and chain. We investigated the properties of the three Fe structures by using the all-electron total-energy full-potential linearized augmented plane wave method. The U term was included in the exchange - correlation functionals constructed on the basis of local density approximation (LDA) and general gradient approximation (GGA). We found that in the case of bcc Fe bulk structure inclusion of the U term leads to the overestimated values of magnetic moment on Fe atom. The values of magnetic moment calculated for Fe in monolayer and chain are in accordance with calculations in which the U term was not included. In general, for each system the calculated values of magnetic moment on Fe sites were larger when the U term was incorporated in the energy functional. In Fe bulk, the value of magnetic moment $2.54{\mu}_B$ for LDA+U larger than $2.25{\mu}_B$ for LDA.

• The Korean Journal of Zoology
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• v.38 no.4
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• pp.443-448
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• 1995

Playback experiments were performed to clarify the degree of song recognition using inter - and intra-populatlon songs of Bush Warbler at Cheongwon, Chungbuk area. Six territorial males were strongly responded to inter- as well as intrapopulation songs. Their responses to the inter- and Intra-population songs were not differed significantly in all measures of latency time, staying time, and closest distance. This result imply that Bush Warbiers in the region did not discriminate the difference between intra- and inter-population songs. It may be the reason that the regional males have little Interactions In song exchange with neighbors by keeping a long Individual distance. In order to investigate the signal value as species recognition releaser, playback of partial songs, prepared from tow distinct regional populations of the spedes were presented to males of the study area. The partial songs presented were made of two portions for each presentation, a whlsde portion only, and a complex syllable portion only. Territorial males responded stronger to the complex syllable portion than the whistle portion of the song. This result indicate that the complex syllable portion conveys more information on the species recognition. As 'releaser' hypothesis suggested formerly, a function of the complex syllable portion In Bush Warbler song is understood In which conveys most spedesIdentifying information. Thus, the result of this playback experiments supports the releaser hypothesis.

• Korean Journal of Plant Resources
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• v.28 no.1
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• pp.93-100
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• 2015

The objective of this study was to determine the effectiveness of rapeseed meal in controlling soil nematode. Two different rapeseed meals (Jeju local rape varieties and 'Sunmang' variety) were mixed with the soil to control nematodes environmentally. When soil physical properties in the rapeseed meal-mixed soils were analyzed, OM (organic matter), $P_2O_5$, Ca, Mg, CEC (Cation Exchange Capacity) value increased. Especially, the level of OM was 3-fold higher than control soil. Glucosinolate content of rapeseed meal was higher in Jeju local rape varieties than 'Sunmang' variety. The major components of glucosinolates were consisted of progoitrin, gluconapin, glucobrassiaca napin, and sinigrin. These components were likely to be involved in reducing nematode density.

• The Journal of the Petrological Society of Korea
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• v.26 no.2
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• pp.143-152
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• 2017

As weathering processes, micro-cavities are formed on the surface of rocks, and in particular, the porous structure is increased in feldspar. Adsorption and antibacterial tests were carried out to clarify the environmental function of porous feldspar porphyry. Almost all the heavy metals were adsorbed in the feldspar filter and the adsorption rate could be controlled by changing the filter length. The shake flask method of fabric coated with 5% and 7% feldspar powder showed very high antibacterial activity of 98% and 99.9%, respectively. The cation exchange capacity at a particle size of $10{\mu}m$ was 114.63 meq/100g probably due to the porous structure. The potential value of porous feldspar porphyry as a resource is sufficient based on the results of the experiment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5671-5676
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• 2011

Volatility Index is the index that represents future volatility of underlying asset implied in option price and expected value of market that measures the possibility of stock price's change expected by investors. The Korea Exchange announces a volatility Index, VKOSPI, since April, 13, 2009. This paper used daily data from January, 2002 through December, 2008 and tested power of Volatility index for future returns of portfolios sorted by size, book-to-market equity and beta. As a result, VKOSPI has the predictive power to future returns and then VKOSPI may be determinants of returns. Also if beta is included when sorting portfolio, the predictive power of VKOSPI is stronger for future portfolio returns.

• Journal of Korean Port Research
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• v.12 no.2
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• pp.303-312
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• 1998

It is necessary to quantitatively asses the influence of tidal currents to analysis the coastal current patterns before or after constructing offshore structures like as breakwaters. This assesment can be made through the use of simulation models designed to reproduce the water movements of the area. And it is very important to predict a phenomenon of pollutant dispersion in the area. In this study, in order to predict the changes of sea water quality for the port development plan, Ilgwang harbour, located at the east coast of Pusan, the numerical computations were carried out. The flow patterns were investigated before and after the development of the harbour bay and coastal area connected on it. The computational models are an extension of earlier work on the flow which used the ADI Method (Alternating Direction Implicit Method) in appling to Osaka Bay by KANEKO et al. The transport of pollutant constituents depends upon the currental characteristics of the water-transporting medium. In the currental flow model, water velocities and water levels are computed throughout the regions of it. These value are then used in the mass-balance equation to obtain the pollutant-constituent transport. As a result of this research, the present water quality of Ilgwang harbour and the coastal areas connected on it was proved out some good condition. The changes of sea water quality due to the port development plan of the Ilgwang habour bay and the coastal area were not large compared with the present condition, but it will be likely able to get worse by increasing the semi-enclosed areas in the harbour bay. In order to improve the water quality of the area after development, the method to activate tidal exchange in the area can be needed, as a mitigation technique.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.5
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• pp.344-352
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• 2020

Covertness and performance are very important design goals in the underwater communications. To satisfy both of them, we proposed efficient underwater communication model which combined multiband and direct sequence spread spectrum method in order to improve performance and covertness simultaneously. Turbo coding method with 1/3 coding rates is used for channel coding algorithm, and turbo equalization method which iterately exchange probabilistic information between equalizer and decoder is used for receiver side. After optimal threshold value was set in Rake processing, this paper analyzed the performance by varying the number of chips were 8, 16, 32 and the number of bands were from 1 to 4. Through the simulation results, we confirmed that the performance improvement was obtained by increasing the number of bands and chips. 2~3 dB of performance gain was obtained when the number of chips were increased in same number of bands.

• Journal of the Korean Institute of Gas
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• v.21 no.1
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• pp.1-5
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• 2017

In the event of toxic gas accidents, soil deposition is a main factor which has an effect on extent of the damage. In this study, it presents the influence of soil deposition properties according to the change of soil depth and the organic matter contents in soil. In this experimentation, the soil deposition device developed in Air Force Research Laboratory in USA is recreated. The tested samples of mixing soil have each value of the organic matter contents. After a variety of synthetic soil were exposed to constant Cl2 concentration, the chlorinity is measured using an anion exchange chromatography(ICS-1100) to quantify the mount of deposition. As the results, the increase of soil depth causes an decreased soil deposition and the increase of exposure time causes an increased soil deposition in surface. Also, the increase of soil deposition mainly depended on the organic matter contents in surface.