• Journal of Power Electronics
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• v.16 no.1
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• pp.102-110
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• 2016

Contactless power transfer technology is gaining increasing attention in city transportation applications because of its high mobility and flexibility in charging and its commensurate power level with conductive power transfer method. In this study, an inductively coupled contactless charging system for a 48 V light electric vehicle is proposed. Although this study does not focus on system efficiency, the generic problems in an inductively coupled contactless power transfer system without ferromagnetic structure are discussed. An active load matching method is also proposed to control the power transfer on the receiving side through a load matching converter. Small signal modeling and linear control technology are applied to the load matching converter for port voltage regulation, which effectively controls the power flow into the load. A prototype is built, and experiments are conducted to reveal the intrinsic characteristics of a series-series resonant inductive power charger in terms of frequency, air gap length, power flow control, coil misalignment, and efficiency issues.

• Environmental Engineering Research
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• v.10 no.6
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• pp.316-327
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• 2005

Constructed wetlands provide several benefits that are not solely limited to storm water management and are becoming common in storm water management. In this research, four recently constructed wetlands underwent in situ and laboratory water sampling to determine their efficiency in removing storm water pollutants over a 5-month period. From the sampling results, it was determined that each of the wetlands was able to reduce the concentration of pollutants in the stormwater. To aid in the assessment of the wetlands against each other, a model was developed to determine the extent of removal of stormwater pollutants over the length of the wetland. The results from this model complimented the data collected from the field. Improvements, such as increased amounts of vegetation were recommended for the wetlands with the aim of increasing the effectiveness. Further investigations into the wetlands will allow for better understanding of the wetland's performance.

• Korean Membrane Journal
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• v.11 no.1
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• pp.15-20
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• 2009

The periodic water-back-flushing using permeate water was performed to minimize membrane fouling and to enhance permeate flux in tubular ceramic ultrafiltration (UF) system for Gongji stream water treatment in Chuncheon city. The filtration time (FT), which was the water-back-flushing period, 2 min with periodic 15 sec water-back-flushing showed the highest value of dimensionless permeate flux ($J/J_o$), and the lowest value of resistance of membrane fouling ($R_f$), and we acquired the highest total permeate volume ($V_T$) of 6.35 L. Consequently FT 2 min at back-flushing time (BT) 15 sec could be the optimal condition in advanced UF water treatment of Gongji stream. Then the average rejection rates of pollutants by our tubular ceramic UF system were 99.4% for Turbidity, 31.8% for $COD_{Mn}$, 22.6% for $NH_3$-N and 65.9% for T-P.

• Journal of Korea Multimedia Society
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• v.22 no.9
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• pp.1122-1131
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• 2019

This paper covers research on terrain construction for unmanned aerial vehicle simulators using spatial information that was distributed by public institutions. Aerial photography, DEM, vector maps and 3D model data were used in order to create a realistic terrain simulator. A data converting method was suggested while researching, so it was generated to automatically arrange and build city models (vWorld provided) and classification methods so that realistic images could be generated by 3D objects. For example: rivers, forests, roads, fields and so on, were arranged by aerial photographs, vector map (land cover map) and terrain construction based on the tile map used by DEM. In order to verify the terrain data of unmanned aircraft simulators produced by the proposed method, the location accuracy was verified by mounting onto Unreal Engine and checked location accuracy.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.9
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• pp.1101-1108
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• 2008

This study was carried out to compare the physiological activities of the extracts from Korean and Chinese Viola mandshurica W. Baker. The water extract from leaves of Chinese V. mandshurica exhibited the highest extraction yields of 30.45 g/100 g and the highest content of total flavonoids as 102.30 mg/g. Also, its ethanol extract showed the best content of polyphenol compounds as 136.16 mg/g. The leaf extract of Korean V. mandshurica produced higher electron donating abilities (EDA) of 92.69% (KLW) and 93.61% (KLE) than the other fractions. The strongest SOD-like activity was shown in the ethanol extract from Korean leaves of 17.28% at the concentration of 1.0 mg/mL. The nitrite scavenging abilities (NSA) of the leaf extracts of V. mandshurica from China were intense over 50% at pH 1.2 and 3.0. In the results of inhibitory rates of xanthine oxidase (XO), both ethanol extracts from Korean and Chinese leaves were higher than the other fractions as 98.67% and 93.80% respectively. Effect of tyrosinase inhibition was the highest in the water extract (45.04%) of Chinese leaves, followed by its ethanol extract (31.36%). The results of EDA, SOD-like activity and XO inhibition of the leaf extracts from Korean V. mandshurica were higher than those of Chinese, on the other hand, determinations on total polyphenol contents, NSA and tyrosinase inhibition were higher in those of Chinese.

• Journal of Korean Home Economics Education Association
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• v.24 no.4
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• pp.59-75
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• 2012

This study investigated the self-perception of body image and awareness of diet of high school students in Zibo city, China. The data were collected from 260 high school students through the self-administered questionnaires. Frequency analysis, t tests, one-way ANOVA, Duncan's multiple range tests, factor analysis and Cronbach's alpha test were conducted by SPSS Windows V.19.0. The results were as follows. In the self-perception of body image, two fifths of the respondents thought of themselves as standard body image. More female respondents thought of themselves as fat persons compared with male respondents. The level of concern about diet was generally low and the mean for pursuit of skinny figure was highest in the awareness of diet. The percentage of correct answers of knowledge about diet was not that high, and one fifths of respondents had experience of diet. The respondents practiced fasting therapy, exercise therapy, food therapy, sweat therapy, drug/appliance therapy, and therapy using professional organization in order for diet.

• Applied Chemistry for Engineering
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• v.5 no.5
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• pp.764-771
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• 1994

Electrochemical synthesis of conductive polypyrrole films was carried out in nucleophilic solvent containing p-toluenesulfonic acid or bezensulfonic acid as supporting electrolyte and dopant. Also characteristics of degradation and improvement of mechanical properties were studied. The conductivity, tensile strength and elongation of the films obtained in dimethyformamide/p-toluenesulfonic acid had the highest value of 10-40S/cm, $25N/mm^2$ and 10%, respectively. The optimum condition of electrochemical synthesis was $2mA/cm^2$ for constant current method and 0.9V for constant potential method containing 0.5M pyrrole and 0.5M p-TSA. The obtained films showed good stability in air and electrode characteristics of secondary battery by reversibility in doping and undoping. The degradation process was 1st order reaction at various temeprature. The activation energy and rate constant of degradation reaction were $1.01JK^{-1}mol^{-1}$ and $3.1{\times}10^{-7}min^{-1}$ respectively at $25^{\circ}C$. For the improvement of mechanical properties, composition of polypyrrole films with various host polymer were investigated and increase of tensile strength and elongation was confirmed.

• Korean Journal of Environmental Agriculture
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• v.16 no.2
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• pp.193-198
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• 1997

The purpose of this study was to find out a suitable resin to remove $NO_3-N$ from groundwater. Four different commercial resins differentiated by type, porosity and nitrate selectivity were used to compare the performance of nitrate removal. Gel type, Type 2 anion exchange resin was preferable when anion concentration of raw water was low. But efficiency of this resin decreased as flow rate increased. However, macroporous type resins were not affected by increasing flow rate. Macroporous resins were preferable when anion concentrations in raw water were high and high flow rate was proposed. And the general type resin showed better efficiency when sulfate concentrations were low. However the nitrate selective resin had better efficiency in treating raw water of high sulfate concentration. From the results, it may be drawn that nitrate selective resins are preferable to general type when a sulfate concentration in groundwater is over 50mg/l.

• Journal of Korean society of Dental Hygiene
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• v.8 no.1
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• pp.73-91
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• 2008

In order to investigate the complaint rates of subjective fatigue symptoms and the degree of job-satisfaction among dental hygienists based on their socio-demographic and job characteristics and to find out the factors related with subjective fatigue symptoms and job satisfaction. The study subjects were recruited from 274 dental hygienists who worked at dental hospitals and clinics in Daejon city and South Chungcheong Province during the period between Jan. 5 and Feb. 11, 2008. They were asked to complete the self-administered questionnaires asking about their socio-demographic characteristics. job characteristics. daily life styles, job satisfaction and subjective fatigue symptoms, and the major finding of the results were as follows : 1. The mean scores of job satisfaction were 3.12V0.47 of the total full scores(5.00). and the highest scores were in the sub-domain of interpersonal relationship. and the lowest scores were pay. The scores of job satisfaction by socio-demographic characteristics and daily life styles were not significantly differences, but in job characteristics, significantly increased with those feeling satisfied with their job. those with appropriate amount of duty amount, those free of jop autonomy, those feeling satisfied with their monthly income. satisfactory personal relations at work. 2. The mean scores of subjective fatigue symptoms were 27.6V10.9 of the total full scores(60.0), and the highest scores were in the sub-group of bodily projection of fatigue(Group III), and they were followed by difficulty in concentration(Group II). dullness and sleepness(Group I) in their decreasing order of magnitude. The scores of job satisfaction by socio-demographic characteristics and daily life styles were significantly increased with the group of lower age, the group of irregularly breakfast habit and the worse subjective health status. Based on job characteristics. the score of subjective fatigue symptoms were significantly increased with those group of lower clinical career and monthly income, those feeling unsatisfied with their job, those with inappropriate amount of duty amount. those satisfactory personal relations at work 3. The correlation of subjective fatigue symptoms with job satisfaction showed a negative correlation with rM-0.198(pM0.000), and job satisfaction were higher according to the lower subjective fatigue symptoms. The correlation among the scores of sub-domain of job satisfaction and the sub-group of subjective fatigue symptoms were significantly positive correlation. 4. The affecting factors of significance on job satisfaction included clinical career, duty amount salary satisfaction, with the explanatory power of 32.9%. Those on subjective fatigue symptoms included the eucation and the subjective health statuts, with the explanatory power of 20.8%. When considering these results, the job-satisfaction and the subjective fatigue symptoms were significantly correlated with the job related factors than factors of socio-demographic characteristics and daily life styles. In addition. if job environments of dental hygienist can improved. their job-satisfaction and subjective fatigue symptoms are suggested to be betters.

• Journal of the Korean Institute of Gas
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• v.24 no.2
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• pp.22-28
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• 2020

In this study, quantitative risk assessment was carried out for city gas high-pressure pipelines crossing through urban rivers. The risk assessment was performed based on actual city gas properties, traffic volume and population and weather data in the worst case scenario conditions. The results confirmed that the social and individual risks were located in conditionally acceptable areas. This can be judged to be safer considering that the risk mitigation effect of protecting the pipes or installing them in the protective structure at the time of the construction of the river buried pipe is not reflected in the result of the risk assessment. Also, SAFETI v8.22 was used to analyze the effects of wind speed and pasquil stability on the accident damage and dispersion distances caused by radiation. As a result of the risk assessment, the safety of the pipelines has been secured to date, but suggests ways to improve safety by preventing unexpected accidents including river bed changes through periodic inspections and monitoring.