• Journal of Korea Foundry Society
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• 제30권6호
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• pp.231-234
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• 2010

The effect of $C_2Cl_6$ for preventing to the surface oxidation and ignition of molten Mg alloy was studied with metallographic analysis, X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The alloy used for this study was AM100A Mg casting alloy with high strength. In order to investigate the surface protective characteristic of this molten alloy by $C_2Cl_6$ addition, we added them into molten AM100A alloy at $700^{\circ}C$ and then the melts were slowly cooled under a protective atmosphere of air containing Ar gas and $C_2Cl_6$ flux addition. The result found that the surface oxidation and ignition reaction of molten AM100A Mg alloy by adding $C_2Cl_6$ flux was more slowly occurred than that of the only a protective atmosphere of containing Ar gas with increasing time. This result was due to a dense protective film formed containing $MgCl_2$ on surface of molten Mg alloy during casting and solidification. The $MgCl_2$ was formed by a reaction of $C_2Cl_6$ with molten Mg.

• The Korean Journal of Zoology
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• 제33권3호
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• pp.297-302
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• 1990

The effects of ginseng saponin on the activity of serum alanine aminoiransferase (ALT) in trained rats were examined. The trained group was given a chronic swimming bout (approx. 90 min/day) for 50 days, and ginseng group was given an oral administration of ginseng saponin (150mg/kg/day) for 2 weeks. Ginseng treated-trained group was given an oral administration of ginseng saponin for 2 weeks prior to the termination of a swimming bout. In this experiment, male rats of Sprague-Dawley strain (250 $\pm$ 20 g) were used. The activities of serum ALT in trained and in ginseng groups increased 72.89% (P < 0.01) and 57.14% (P < 0.01) than in control groups, respectively. Also, the activities of serum ALT increased 69.66% (P <0.01) in saline treated-trained group, and 79.31% (P < 0.01) in ginseng treated-trained group than in control groups which were given saline solution and kept sedentary. The effect of ginseng saponin, as revealed by comparing the ginseng treated-trained group with the saline treated-trained group, was not significant. The present study suggests that training and ginseng saponin significantly increased the activity of serum ALT in rats, but that, in ginseng treated-trained group, ginseng saponin did not raise any further the increased activity of serum ALT by training.

• Korean Journal of Optics and Photonics
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• 제4권4호
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• pp.442-446
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• 1993

A flashlamp pumped Ti: sapphire laser was designed and fabricated in the laboratory. In order to find out the optimum pumping condition, three kinds of discharge circuits of which the pulse width are 10${\mu}s$, 45${\mu}s$, 65${\mu}s$ were designed. The fluorescent energy converter LD-490 of which the fluorescence spectra is coincident to the absorption band of Ti: sapphire was used to improve the laser efficiency. The laser output characteristics for three different concentrations of LD-490 and for three different pumping pulse widths were measured. As a result, the shorter the flashlamp pulse width, the higher the overall efficiency was achieved. When pumping light pulsewidth was 10${\mu}s$, the best efficiency was obtained at the concentration 1.0${\times}10^{-3}$mol/l of LD-490 dye. At lower concentrations the efficiencies were decreased.

• Journal of the Korean Magnetics Society
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• 제16권1호
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• pp.1-5
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• 2006

The crystallographic properties and cation distribution of oxyspinels ferrite $Co_xFe_{1-x}O_4$ thin films have been explored by X-ray diffraction, vibrating sample magnetometer (VSM), and conversion electron $M\"{o}ssbauer$ spectroscopy (CEMS). Thin films are prepared by sol-gel method. Normal spinel structure is transformed to inverse spinel structure with increasing Co concentration CEMS results indicate that most of $Fe^{3+}$ ions are substituted to $Co^{3+}$ions. Accordingly $Co^{2+}$ ions on octahedral site migrate to tetrahedral site. Magnetic moment is decreased with increasing Co concentration, which means high spin $Fe^{3+}$ ions are replaced by low spin $Co^{3+}$.

• Korean Journal of Veterinary Research
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• 제39권3호
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• pp.554-559
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• 1999

The purpose of this study was to evaluate effect of chitosan-oligosaccharides (CHIOL) on hydrophobicity of pathogenic E coli including a field isolate from suckling piglet with diarrhea, E coli-O157 : H7, and E coli-O149 : K88ac. E coli field isolate appeared adhesion of 100% to n-hexadecane between 0.00125% and 0.05% CHIOL. E coli-O157 : H7 occurred adhesion of 69% and 64% under the level of 0.00125% and 0.025% CHIOL, respectively. E coli-O149 : K88ac showed adhesion of 100% in higher than 0.025% CHIOL. For cationic action, the adhesion of E coli isolate and E coli-O149 : K88ac to n-hexadecane were inhibited at level of higher than 10mM $Ca^{2+}$ but did not induce any difference among the concentrations used(p < 0.01). However, the adhesion of E coli-O157 : H7 to n-hexadecane was inhibited at level of higher than 50mM $Ca^{2+}$. In a field trial, control piglets showed average mortality of up to 58% during 3 days after the onset of diarrhea. In contrast, the prevalence of E coli-induced diarrhea in CHIOL-treated groups without mortality was dropped down to average 34% on the 1st day after the treatment of CHIOL, and average 2% on the 4th day. After then, piglets with diarrhea was not present. In conclusion, the low concentrations of CHIOL were most likely to associate with the enhancement of hydrophobicity to pathogenic E coli. Calcium inhibited the hydrophobicity of E coli by CHIOL. These results suggested that CHIOL could be played an efficient and reliable role in treating enteric colibacillosis of piglets.

• The Journal of the Korea Contents Association
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• 제13권4호
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• pp.23-34
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• 2013

This study would verify the validity of two transmission technology, 'Clear QAM' and '8VSB'. 'Clear QAM' and '8VSB', the transmisson technology, have been suggested as the concrete alternatives in the situation that half of subscriber of multi channel tv service have been still out of benefit from digital convert. In this study, we have shown that the introduction of 'Clear QAM' and '8VSB' should ease economical burdens and information minority group without extra set-top box. But there is another concern that it should negatively affect on the contents industry by a devaluation of the multi channel tv service or by an infringement of copyright. In these reasons, it is still difficult to solve the related concern, though the government have to set up the politic goal for the related industry as well digital convert. This study suggested that Korea Communication Commission consider above-mentioned technology temporarily, and reconsider 'Clear QAM' around the completion of the digital convert project.

• The Journal of the Korea Contents Association
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• 제13권7호
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• pp.190-202
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• 2013

Government has been doing policy PR to acquire policy support and government trust of people. Because it is believed that policy support and government trust of people can be a driving force of government activity. In this perspective, this study analyzed the effects of government's policy PR on the policy support and government trust of people focusing on the corporation partnership policy. According to the results, first people who have more positive attitude to the policy PR activity and its result, they have more positive attitude to the policy and its support. Second, people who have positive attitude to the corporation partnership policy, they have more positive attitude to the policy support. Third, people who have more positive attitude to policy support, they have more government trust(professionalism, ethicality, reliability). These results show that policy PR is effective method for inducing policy support and government trust of people. And for improving government trust. it is needed not only policy PR but also fair and transparent execution of policy.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제20권5호
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• pp.15-23
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• 2020

Automated driving car is drawing attention as a seminal service representing 4th industrial revolution era based on 5G network, AI, IOT and sensor technology. automated driving car is expected to evolve into the final level which does not require driver's input. Drivers are able to consume new additional time in private space. Many industries started to compete to control these time and space. Media industry is expecting quite big change due to the introduction of automated driving cars. This research examines the impact of the media industry and social & institutional issues of automated driving cars based on depth interviews of experts. The introduction of automated driving cars is giving new opportunity for media industry as contents provider. Telcos and IT corporations are expected to compete each other to get the control of infotainment systems of automated driving cars. The reform of current regulations regarding car driving is pointed as important task to protect private information and the introduction of automated driving cars.

• Journal of Digital Convergence
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• 제12권5호
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• pp.501-515
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• 2014

The enforcement of the digital switch been two years, but more than half of the viewers are still not enjoying the benefits of it. Therefore, the government proposed that 8VSB transmission method so that majority of the viewer is able to enjoy the benefits of a digital switch. However, the claim has been suggested that 8VSB transmission method will have negative impacts on broadcast market feedback. In this regard, this study verified the effect of 8VSB and the method of minimization on the broadcast market. This study has conducted in-depth interviews concerned experts to achieve this purpose. Results of an interview revealed that the negative impact on the market of content and platforms, network is very small. In other words, the majority of the experts argued that the policy of government about 8VSB transmission are inadequate and it is improved to broaden the choice of the broadcast consumer.

• Research in Community and Public Health Nursing
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• 제14권1호
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• pp.55-65
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• 2003

Purpose: The purpose was to investigate the factors influencing the alcohol consumption behavior of adolescents to provide basic data for a nursing intervention program to improve health management and prohibit alcohol consumption. Method: The subjects were 306 university students, living in K city in Chungnam province from April 1 to 20th, 2002. The instruments used were the alcohol consumption behavior scale, that is the drinking intensity score, and developed by Shin(1998)'s scale of drinking problem, refusal self-efficacy scale by Aas et. al.(1995), alcohol expectancy by Goldman et. al. (1989), TPQ scale by Cloninger(1991), depression scale by Zung(1974), family cohesion scale by Olson et. al. (1983). The data were analyzed using descriptive statistics, Pearson correlation coefficient, t-test, ANOVA, and stepwise multiple regression by using SPSS & SAS program. Results: The multiple regression analysis revealed that the most powerful predictor of alcohol consumption behavior was the influence of friends (drinking everyday) (17.0%). A combination of alcohol expectancy (8.0%), influence of friends (4.0%), father's influence (2.0%), depression(2.0%), refusal self-efficacy (1.0%), personality of harm avoidance(1.0%), and monthly pocket money (2.0%) accounted for 38.6% of the variance in alcohol consumption behavior. Conclusion: From the results, we recommend to use the database that develops nursing intervention program for decreasing the alcohol consumption behavior including the influencing factors in university students.