• Polymer(Korea)
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• v.32 no.1
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• pp.70-76
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• 2008

The PES-g-BTCA membrane was synthesized by UV irradiation method and then used to be modified into the PES anion exchange membrane by the amination reaction. Their chemical structures and adsorption properties were investigated. The degree of grafting and amination were increased with increasing the reaction time and had the maximum values of 138% and 1.20 mmol/g at 80 min, respectively. The initial thermal degradation temperature of PES membrane was $400^{\circ}C$. Which was reduced as the surface modification reaction had proceeded. The values of contact angle for PES membrane were decreased from 68.1 to $40.2^{\circ}$ with increasing the extent of amination, the water up-take and ion exchange capacity were also increased with increasing UV irradiation time until 80 min. The average pore size and BET surface area were decreased in order of PES, PES-g-BTCA, and aminated PES ion exchange membrane. Their average pore sizes were 624.8, 359.7, and 138.5 ${\AA}$, and their surface areas were 10.1,9.7 and 1.7 $m^2/g$, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.1
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• pp.1-10
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• 2001

In this paper, a multistage parallel interference canceller (MPIC) and a partial multistage parallel interference canceller (PMPIC) are employed as a technique for improving the performance of the asynchronous DS-CDMA systems. The degree of the effect of the timing errors and phase errors on the interference cancellation capability of two types of cancellers is theoretically analyzed and the computer simulation is performed to confirm the analytical results. From the results, the large performance improvement is obtained by employing MPIC and PMPIC with perfect synchronization over the conventional matched filter, and the performance improvement obtained by MPIC and PMPIC is very close to each other as the number of the stage of MPIC and PMPIC increases. When the timing errors and phase errors are considered (in the case of imperfect synchronization), the performance improvement reduces as the performance degradation at the first stage (no cancellation) has a bad effect on the decision statistics at each stage. However MPIC and PMPIC have the strong interference cancellation capability in spite of imperfect synchronization as the number of the stage increases. An interference canceller, which has the strong interference cancellation capability as well as lower complexity for the implementation, is needed for practical systems with timing errors and phase errors because the perfect synchronization is impossible. Therefore, the excellent tradeoff between complexity and performance offered by PMPIC makes it an attractive approach for practical systems.

• Journal of Soil and Groundwater Environment
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• v.27 no.spc
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• pp.51-63
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• 2022

In this study, the TPH(Total Petroleum Hydrocarbon) contamination and microbial ecological characteristics in petroleum-contaminated site were investigated through the correlation among the vertical TPH contamination distribution of the site, the geochemical characteristics, and the indigenous microbial ecology. The high TPH concentration showed in the vicinity of 3~4 m or less which is thought to be affected by vertical movement due to the impervious clay layer. In addition, the TPH concentration was found to have a positive correlation with Fe²⁺, TOC concentration, and the number of petroleum-degrading bacteria, and a negative correlation with the microbial community diversity. The microbial community according to the vertical distribution of TPH showed that Proteobacteria and Firmicutes at the phylum level were dominant in this study area as a whole, and they competed with each other. In particular, it was confirmed that the difference in the microbial community was different due to the difference in the degree of vertical TPH contamination. In addition, the genera Acidovorax, Leptolinea, Rugoshibacter, and Smithella appeared dominant in the samples in which TPH was detected, which is considered to be the microorganisms involved in the degradation of TPH in this study area. It is expected that this study can be used as an important data to understand the contamination characteristics and biogeochemical and microbial characteristics of these TPH-contaminated sites.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.9
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• pp.1822-1829
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• 2016

DGPS Reference station is established in Korea for improvement of GPS navigation accuracy and needs of integrity. Recently, DGPS stations provide user positioning information on land as well as ocean. However, this paper investigated visibility and interference environment for performance degradation of Chung-ju DGPS reference station. In case of Young-do reference station, visibility and interference environment were satisfied with reference standard. In case of Chung-ju reference station, visibility was satisfied with 7 degree elevation angle. However, interference environment was not satisfied with reference standard of -50dBm. This paper proposed time differential measurement analysis method excluding error of signal noise for analyzing measurement error. Chung-ju reference station measurement analysis result is three times the error than on Young-do in Dec, 2015. In addition, this paper has confirmed measurement performance degradations because of reference station equipment problem. Future study will be carried out performance analysis of 17 DGPS reference station.

• 전자공학회논문지 IE
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• v.44 no.3
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• pp.23-34
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• 2007

For an effective phase multiplexing in a volume holographic system, four types of phase code, pseudo random code(PSC), Hadamard matrix(HAM), pure random code(PRC), equivalent random code(ERC), used as reference beams are generated. In case of $32{\times}32$ address beam, a phase error with 0%, 5%, 10%, 15%, 20%, and 25% error rate, is purposely added to the real phase values in order to consider the practical SLM's nonlinear characteristics of phase modulation in computer simulation. Crosstalks and SNRs(signal-to-ratio) are comparatively analyzed for these phase codes by the auto-correlation and cross-correlation. PSC has the lowest cross-correlation mean value of 0.067 among four types of phase code, which means the SNR of the pseudo random phase code is higher than other phase codes. Also, the standard deviation of the pseudo random phase code indicating the degree of recalled data degradation is the lowest value of 0.0113. In order to analyze the affect by variation of pixel size, simulation is carried out by same method for the case of $32{\times}32$, $64{\times}64$, $128{\times}128$, $256{\times}256$ address beams.

• Journal of Conservation Science
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• v.29 no.1
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• pp.47-54
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• 2013

The following study tests for the effects of mordants on the production of restoration papers during the conservation process of damaged paper artifacts. For this, four different types of synthetic mordants that are being marketed currently ($K_2CO_3$, $AlK(SO_4)_2{\cdot}12H_2O$, $Cu_2SO_4{\cdot}5H_2O$, $FeSO_4$) were selected to produce samples for measuring variable properties through artificial degradation. The research conducts tests for changes in color, tensile index, and pH level (degree of acidity). The results for changes in color have shown that the value of ${\Delta}E^*ab$ of $K_2CO_3$ mordant sample was the highest, and the tests for tensile index have shown that the strength of dyeing sample was decreased in accordance with the aging time, but Changes according to the mordant was not evident. Finally, the findings for pH level have shown that samples with $Cu_2SO_4{\cdot}5H_2O$ and $FeSO_4$ have pH levels drop below 6. As a result, the research have concluded that mordants used for dyeing restoration paper were identified to have an affect in the dyeing and aging characteristics of the paper.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5088-5094
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• 2014

Hovenia dulcis extract (HDE) has positive effects on alcohol degradation, recovery of liver damage and antioxidant activities. This study examined whether HDE exerts an ameliorative effect on inflammatory orifacial pain in an animal algesic model with formalin. The animals (rats) were divided into four groups: group I (control), group II (right facial subcutaneous injection of 5% formalin, inflammatory orifacial pain group), group III (5% formalin + distilled water administration), and group IV injection (5% formalin + 4.5 ml/kg of HDE), respectively. The scores from the scratch and effleurage tests were applied to evaluate the differences between three groups. The expression of p38 MAPK, iNOS and Nrf2 in the brain and medulla oblongata, which are involved in pain regulation, inflammation, antioxidation and nitric oxide production, were analyzed by western blot. The degree of orifacial pain was significantly lower in group IV than in groups I, II and, III. The expression of p38MAPK, iNOS and Nrf2 in the brain and medulla were also lower in group IV than in the other groups. These findings suggested that a Hovenia dulcis extract can attenuate inflammatory orifacial pain by suppressing the expression of p38 MAPK, iNOS and Nrf2.

• Management & Information Systems Review
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• v.31 no.4
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• pp.261-286
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• 2012

Rumors are widely prevalent in marketplace and It can be problematic and dangerous for the company's reputation and damages their image. Recently, many companies are given trouble by rumors. As getting invigorates the social media, there is high possibility to shape the vicious rumors without any confirmation whether information is true or not. It affects the companies' reputation and trust they have built for long time, also sales drop off. Despite numerous denials, the rumor persisted, keeping occur again and again all the times. Refutation purposes to decrease levels of belief in a rumor. First, establish Study 1 that a variation in identification influences the impact of a rumor on individuals' beliefs. Furthermore, we analyze the effectiveness of a refutation under varying degree of one's level of identification with the rumor object. According to research result, the response pattern of identification and disidentificaion consumers are very different. Disidentifiers, who engaged in systematic processing, believed the rumor less only when the refutation contained strong arguments. Identifiers, processing heuristically, remained unbelieving in the rumor. Study found that identification is an important moderator of consumer response to negative rumors. These defensive processes alleviate the bad influence of that information, and also can reduce the likelihood of attitude degradation.

• Applied Biological Chemistry
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• v.40 no.2
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• pp.95-100
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• 1997

This study was aimed to survey inexpensive and reliable sources of chitinase from the animal origin. The stomach and its content of the broiler, the cod, the yellowtail and ${\beta}-glucuronidase$ from snail gut showed a considerable chitinolytic activity, while those of the bas didn't have any detectable activity. These crude enzymes was found to have both endo- and exochitinase activity. The effects of pH and temperature on the enzyme activity were variable. The hydrolytic products of colloidal chitin by the enzyme preparation from the broiler and the cod were chitooligomers having the degree of polymerization between 3 and 5. Furthermore we observed the chitosanolytic activity from these enzymes. In the degradation of chitosan the chyme of the broiler had the highest activity and ${\beta}-glucuronidase$ from snail gut followed. On the basis of the fact that the by-product of the broiler was not only commercially available but also the most potent in the endochitinase activity and the lowest in the exochitinase activity, we conclude that the gizzard and its chyme are considered as the most suitable source of the industrial chitinase among animals studied in this paper.

• Applied Biological Chemistry
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• v.38 no.1
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• pp.42-48
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• 1995

The experiment was carried out to purify and to investigate the properties of the cyclodextrinase produced from Bacillus megaterium KFCC 11855. The enzyme was partially purified with $(NH_4)_2SO_4$ and chromatography on DEAE-trisacryl, Ultrogel AcA 34, DEAE-trisacryl and Ultrogel HA. The optimum temperature and pH of the purified enzyme were $60^{\circ}C$ and 6.0, respectively. The enzyme was stable at the temperature of $45^{\circ}C$ below and at the pH range of $6.0{\sim}9.0$, respectively. The Km value for ${\gamma}-cyclodextrin$ was 0.903 mM. The enzyme activity was increased by $Mg^{2+}$ and $Mn^{2+}$, but decreased by $Hg^{2+}$ and $Cu^{2+}$. The enzyme degraded ${\gamma}-cyclodextrin$ but not ${\alpha}-cyclodextrin$. The degree of ${\beta}-CD$ degradation by the enzyme was very low. The decomposed products of ${\gamma}-cyclodextrin$ by the enzyme were mainly glucose, maltose and a little amount of maltotriose.