• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.1
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• pp.545-551
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• 2011

Recently, demands for generating high quality tap waters are increasing with high concern of water pollution and corrosion of water pipelines. For the reasons, developing water quality stabilization technique in water purification system is sought rather than replacing to a new pipelines. In this study, high-purity liquid lime($Ca(OH)_2$) was introduced for a water quality stabilization technique in water purification process and simulated water distribution system of pilot-scale size was applied to evaluate anti-corrosion control effect. The effect of anti-corrosion control was calculated in terms of LSI(Langelier Saturation Index) In conclusion, the result of pilot plant showed improvement of corrosiveness by liquid lime($Ca(OH)_2$) with reduction of released iron(Fe). Application of anti-corrosion control technique to the mild steel coupon and the copper coupon were effective by indicating 35.4, 44.5% of improvements. Besides, sample pipes which were treated with liquid lime had formated more thicker layer of corrosion product inside of pipes. As a result, the process of injecting water stabilizer can greatly contribute to the high quality of tap water.

• Journal of Korean Society of Forest Science
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• v.87 no.2
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• pp.188-193
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• 1998

Soil pH change is an important factor which determines soil chemical properties. It is an indicator of the effect of urban environmental pollution on soils and plant growth. The objective of this study was to assess the effect of air pollution on the soil of Seoul urban forests during the course of the air pollution being dipersed toward suburb area. Study sites were divided into four sections of concentric circles with 5km interval. Soil samples were collected from A and B horizons in the urban forests, and analyzed for soil pH, soil buffer capacity, cation exchange capacity, and base saturation. Soil pH ranged from 3.96 to 5.08 for A horizon and from 4.10 to 5.25 for B horizon, which were not significantly different among the sections. However, there was a trend of soil pH lowered at the sections close to the urban center. Soil buffer capacity was lower at 0-5km and 5-10km sections compared to that at the outer sections. Cation exchange capacity and base saturation were not different significantly among the sections. Following the pattern of air pollutants being dispersed from urban center to suburb, soil acidification was observed at the urban forests in Seoul area. Low level of soil buffer capacity toward the urban center was an indicator of soil acidification at the urban forests.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.9 no.2
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• pp.169-175
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• 2006

Purpose: Esophagogastroduodenoscopy (EGD) is a very useful procedure in diagnosing gastrointestinal diseases. However, there can be some difficulty in performing this procedure in children due to the associated discomfort. Recently, sedative agents such as midazolam have been introduced to alleviate this problem quite successfully. In our study, we attempted to confirm the safety and efficacy of midazolam use by monitoring the vital signs of children undergoing endoscopy. Methods: We analyzed data on 244 children who received EGD in the department of pediatrics at Severance Hospital, Yonsei University between August 2003 and July 2005. We evaluated $O_2$ saturation, heart rate and change of mental status before and during the procedure and analyzed the results using the SPSS 12.0 package (Chi-square test, cross table method, etc.). Results: There was no significant difference in vital signs measured before and during EGD between midazolam treated and non treated children. There was no significant relationship between the amount of midazolam given and $O_2$ saturation or a change of mental status. Regarding the $O_2$ saturation, it was decreased during EGD in both groups with p<0.01 though no difference was noted between the groups; the $O_2$ level was maintained above 95% in all patients. The heart rate was also increased during EGD in both groups with a p<0.01; however, no significant difference was noted between the groups. Conclusion: We confirmed the safety of low dose midazolam by evaluating the vital signs of children during endoscopies. However, the doses used were not sufficient for sedation or to obtain an amnestic effect.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.1
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• pp.11-16
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• 2012

Effect of supplementary intranasal midazolam on oral sedation of children The purpose of this study was to compare the cardiopulmonary parameters of two sedation regimens during dental treatment: (1) Oral chloral hydrate(CH) and hydroxyzine(HZ) with nitrous oxide-oxygen($N_2O/O_2$) inhalation(CH-HZ group); (2) Oral chloral hydrate(CH) and hydroxyzine(HZ) with nitrous oxide-oxygen($N_2O/O_2$) inhalation and supplementary intranasal(IN) midazolam administration(MIDA group). Among the patients of OO hospital who received dental treatment under sedation over the past 5 years, 44 patients were selected for each group of CH-HZ and MIDA according to their age, gender and weight. Following parameters that were recorded every 5 minutes were compared: 1) Heart rate(HR) 2) $O_2$ saturation 3) End tidal carbon dioxide concentration($EtCO_2$) 4) Respiratory rate(RR) 33 patients of Group MIDA who have complete data of 15 minutes before and after supplementary IN midazolam administration were selected. And measurements 15 minutes before and after midazolam administration in same patient were evaluated. The results were as follows: 1. Heart rate was significantly higher in MIDA group than in CH-HZ group, but it was within normal range. 2. Comparing HR, $O_2$ saturation, EtCO2, RR between before and after of supplementary IN midazolam administration in the same patient, the differences were not statistically significant.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3006-3013
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• 2015

Flat tube heat exchangers can improve the thermal performance significantly compared with round tube heat exchangers. For proper design of flat tube heat exchangers, one should know the tubeside heat transfer coefficients. In this study, convective boiling heat transfer coefficients of R-410A were obtained in a flat extruded aluminum tube with $D_h=1.41mm$. The test range covered mass flux from 200 to $600kg/m^2s$, heat flux from 5 to $15kW/m^2$ and saturation temperature from $5^{\circ}C$ to $15^{\circ}C$. The heat transfer coefficient curve shows a decreasing trend after a certain quality(critical quality). The critical quality decreases as the heat flux increases, and as the mass flux decreases. The early dryout at a high heat flux results in a unique 'cross-over' of the heat transfer coefficient curves. The heat transfer coefficient increases as the mass flux increases. At a low quality region, however, the effect of mass flux is not prominent. The heat transfer coefficient increases as the saturation temperature increases. The effect of saturation temperature, however, diminishes as the heat flux decreases. Both the Shah and the Kaew-On et al. correlations reasonably predicted the present data.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.5
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• pp.423-430
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• 2005

In this paper, we have simulated a Symmetric Dual-gate Single-Si TFT which has three split floating $n^{+}$ zones. This structure reduces the kink-effect drastically and improves the on-current. Due to the separated floating $n^{+}$ zones, the transistor channel region is split into four zones with different lengths defined by a floating $n^{+}$ region. This structure allows an effective reduction of the kink-effect depending on the length of two sub-channels. The on-current of the proposed dual-gate structure is 0.9 mA while that of the conventional dual-gate structure is 0.5 mA at a 12 V drain voltage and a 7 V gate voltage. This results show a $80 {\%}$ enhancement in on-current by adding two floating $n^{+}$ zones. Moreover we observed the reduction of electric field In the channel region compared to conventional single-gate TFT and the reduction of the output conductance in the saturation region. In addition we also confirmed the reduction of hole concentration in the channel region so that the kink-effect reduces effectively.

• Journal of the Korean Wood Science and Technology
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• v.2 no.2
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• pp.5-7
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• 1974

1. This study indicates that above the fiber saturation point the drying rate can be increased with increasing the velocity of the air circutation, i.e., the drying rate of sample boards is proportional to the air velocity, but below the fiber saturation point, the effect of the velocity of air circulation is very low as shown in Figs. 1 and 2. 2. Under the controlled temperature and humidity in the kiln, the more the sample boards have moisture, the higher drying rate of it can be obtained. In other words, this means that even though in the case of drying various moisture content of wood, at the final drying stage, approximately the same percentage of moisture content of wood can be secured by employing the higher velocity of air circulation. 3. This study shows that the rate of drying in kiln changes distinctly at the fiber saturation point, i, e., above the fiber saturation point, the drying curve shows concave aginst the X axsis, but below the fiber saturation point, in the range from 30 percent of moisture content to 20 percent of moisture content, the curve shows convex as shown in Fig. 3. As the drying progresses, however, the drying curve shows concave again below 20 percent of moisture content. This means that inflection point of drying curve may be located clearly at the fiber saturation point, i.e., 30 percent of moisture content. As mentioned above, the 30 percent of moisture content of wood at which the inflectional point appears can be recognized as a critical point, i. e., the fiber saturation point at which all free water was removed from wood. The existence of inflectional point indicates that the evaporation of hygroscopic water in a cell wall is more difficult than the evaporation of free water in a cell cavity and the minor space of cell wall. The convex curve in the range of moisture content from 30 percent to 20 percent means that the evaporation of capillary condensed water has a tendency of the same rates of drying approximately, but as approaching to the 20 percent of moisture, the transfusion of moisture from wood becomes difficult because of having less moisture in cell wall. Below 20 percent of moisture content, the drying curve shows concave again, which means that it is difficult to remove the moisture located nearer to the surface of cellulose molecules and the surface bound water. These relations were revealed in Fig. 4. In comparison AC curve which does not have the two inflection points with BD curve which has two inflection points, i.e., Band D, they are mentioned already, by existence of the inflection points, the curve BD shows that the change of drying rate in the interval from 20 percent of moisture content to 30 percent of moisture content is not greater than in the case of the curve AC in the same interval. At the inflection point of 30 percent of moisture content, it can be noticed that the changing of the drying rate is very conspicuous. This phenomenon also can be recognized, as it is noticed by the Fig. 3, the drying rate from green to 30 percent of moisture content is very great. But the inclination of the curve is very slow from 30 percent of moisture content to 20 percent of moisture content, i.e., the inclination of the curve becomes almost horizontal lines. Acknowledgments Gratitude is expressed to Fred E. Dickinson, Professor of 'Wood Technology, School of Natural Resources, University of Michigan, USA for his suggestion to carry out this study.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.3
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• pp.1043-1064
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• 2020

A kind of Subjective Imaging Effect Assessment (SIEA) method and its applications on intelligent imaging terminal design in engineering site are presented. First, some visual assessment indices are used to characterize the imaging effect: the image brightness, the image brightness uniformity, the color image contrast, the image edge blur, the image color difference, the image saturation, the image noise, and the integrated imaging effect index. A linear weighted function is employed to carry out the SIEA computation and the Analytic Hierarchy Process (AHP) technique is used to estimate its weights. Second, a SIEA software is developed. It can play images after the settings of assessment index or assessment reaction time, etc. Third, two cases are used to illustrate the application effects of proposed method: the image enhancement system design for surveillance camera and the imaging environment perception system design for intelligent lighting terminal. A Prior Sequential Stimulus (PSS) experiment is proposed to improve the evaluation stability of SIEA method. Many experiment results have shown the proposed method can realize a stable system design or parameters setting for the intelligent imaging terminal in engineering site.

• Transactions on Electrical and Electronic Materials
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• v.7 no.2
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• pp.53-57
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• 2006

In this paper, a Symmetric Dual-gate Single-Si TFT, which includes three split floating n+ zones, is simulated. This structure drastically reduces the kink-effect and improves the on-current. This is due to the separated floating n+ zones, the transistor channel region is split into four zones with different lengths defined by a floating n+ region. This structure allows effective reduction in the kink-effect, depending on thy length of the two sub-channels. The on-current of the proposed dual-gate structure is 0.9 mA, while that of the conventional dual-gate structure is 0.5 mA, at both 12 V drain and 7 V gate voltages. This result shows an 80% enhancement in on-current. In addition, the reduction of electric field in the channel region compared to a conventional single-gate TFT and the reduction of the output conductance in the saturation region, is observed. In addition, the reduction in hole concentration, in the channel region, in order for effectively reducing the kink-effect, is also confirmed.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.253-259
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• 2006

The effect of DC electric fields on the flame extinction was investigated experimentally in counterflow configurations for the methane/oxygen/nitrogen diffusion flame. The electric fields was applied by connecting the high voltage and ground terminals to the upper and lower burners, respectively. In case of having electric fields, several modes of flame extinction was observed according to the electric field intensity and strain rate defined by the exit velocity. To visualize and characterize the flame structure and intensity, planar LIF technique was adopted for OH radicals. Consequently, several length scales, including the flame width, thickness, and height from the burner tip, were introduced to explain the various flame behaviors and to characterize the flame extinctions. It was found that the variation of flame width and the chemical reaction are strongly related to a critical electric field intensity, thus the various modes of diffusion flame extinction could be observed due to the electric fields.