• Journal of Power Electronics
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• 제16권3호
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• pp.883-893
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• 2016

This paper presents a comprehensive analysis of the spurious turn-on phenomena in phase-shifted full-bridge (PSFB) converters. The conventional analysis of the spurious turn-on phenomenon does not establish in the PSFB converter as realizing zero voltage switching (ZVS). Firstly, a circuit model is proposed taking into account the parasitic capacitors and inductors of the transistors, as well as the parasitic elements of the power circuit loop. Second, an exhaustive investigation into the impact of all these parasitic elements on the spurious turn-on is conducted. It has been found that the spurious turn-on phenomenon is mainly attributed to the parasitic inductors of the power circuit loop, while the parasitic inductors of the transistors have a weak impact on this phenomenon. In addition, the operation principle of the PSFB converter makes the leading and lagging legs have distinguished differences with respect to the spurious turn-on problems. Design guidelines are given based on the theoretical analysis. Finally, detailed simulation and experimental results obtained with a 1.5 kW PSFB converter are given to validate proposed analysis.

• 한국해양공학회지
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• 제14권2호
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• pp.13-18
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• 2000

Recently due to the environmental pollution and the requirement for the substitute energy the interest for development of the solar energy system has been highly escalated It has been approved that the solar energy is a very useful on e because of purity and low cost. Some studies about the evaluation of solar radiation on the land has been carried out but few studies on the sea. This paper deals with a study on the evaluation of solar radiation on the sea. The experiments were carried out on the training vessel on the adjacent water of Korea Japan and China for twenty days. The distributions of solar radiation from the sea were changed into nonlinear in from according to the temperature. The solar radiation on the sea has a great influence on the velocity of wind as well as the temperature The distribuition of solar radiation has higher values on the track of the coastal sea than the open sea at same conditions.

• Journal of Oral Medicine and Pain
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• 제13권1호
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• pp.23-33
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• 1988

The purpose of this study was to standardized and classify the coordination pattern among the chewing side and non-chewing side masseter and anterior muscles, in terms of EMG values on lateral excursion, clenching, and mastication in presence of the non-chewing side. In this study, 25 subjects were selected for experiment of lateral excursion, clenching and mastication and EMG value of the masseter and anterior temporal muscle on both sides were recored 2 times respectively. The bioelectric processor model EM2(Myo-tonic research, INC. U.S.A.) with the surface electrodes were used to record the EMG activity during all experimental procedures. The results were as follows : 1. During lateral excursion on intereference of non-chewing side, the EMG values of the temporal muscle were significantly more prominent than those of the temporal muscle on the non-chewing side. The EMG values of non-chewing side were significantly more prominent than those of chewing side on the both side masseter muscle and those of chewing side were significantly more prominent than those of non-chewing side on the both side temporal muscle. 2. During clenching on the occlusal interferance, the EMG values of non-chewing side masseter muscle were most prominent. 3. During mastication on the occlusal interferance, the EMG values of the chewing side temporal muscle were most prominent and those of non-chewing side temporal muscle were the lowest. 4. The EMG values of temporal muscle of non-chewing side on interferance were significantly more prominent than those of canine guidance during lateral excursion. 5. During clenching on the occlusal interferance, the EMG values of the masseter and the temporal muscles of the non-chewing side were significantly more prominent than canine guidance, but those of chewing side temporal muscle on canine guidance were significantly more prominent than those of interferance. 6. During mastication on canine guidance, the EMG Values of the temporal muscle on the chewing side, the masseter muscle on the chewing side and the temporal muscle on the non-chewing side were more prominent than those of interferance, but temporal muscle of non-chewing side was not different between canine guidance and occlusal interferance on non-chewing side.

• Child Health Nursing Research
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• 제4권1호
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• pp.17-30
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• 1998

In order to investigate the effects of a decreased activity on skinfold thickness, circumference and muscle strength of the extremities during the recovery period following heart surgery, skinfold thickness, circumference and muscle strength of the extremities were measured on days 0, 3, 6, and 9 following the surgery, and compared with those on the arrival day of intensive care unit. Skinfold thickness was measured using a skinfold caliper(Saehan Cor., Korea), circumference of the limbs were measured with a tape measure, upper extremity strength was determined using the Takei grip dynamometer and lower extremity strength was measured by pressing the flatfoot on an electronic digital health meter while tying on a bed. Results from this study were thus : 1. Skinfold thickness of triceps, quadriceps and gastrocnemius muscle on days 3, 6, 9 following the heart surgery was not significantly different from that of on the day of operation. 2. Circumference of midupperarm and midthigh on days 3, 6, 9 following the heart surgery was not significantly different from that of on the day of operation. Circumference of midcalf on days 3, 6 following the heart surgery was not significantly different from that of on the day of operation, while that of midcalf on day 9 following the surgery decreased significantly compared with that of on the day of operation. 3. Muscle strength of the upper extremity was not significantly different from that of on the day of operation, while that of the lower extremity on day 9 following the surgery decreased significantly compared with that of on the day of operation. From these results, it may be concluded that circumference and muscle strength of lower extremity can be decreased due to the postoperative inactivity following heart surgery in congenital heart disease children.

• 한국환경과학회지
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• 제25권8호
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• pp.1077-1085
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• 2016

The present study was investigated the effect of recycled coir organic substrates on the growth of different vegetable crops. The recycled coir had better physical and chemical properties than the new coir. The growth of tomato plant was better on the coir substrate that had been used for 2 years than that on the new coir substrate. The average number of tomato fruits was 108 on the new coir substrate, while it was 179 and 165 on the coir substrate used for 1 and 2 years, respectively. The growth of cherry tomato plant was also better on the coir substrate used for 2 years than that on the new coir substrate. The average number of cherry tomato fruits was 43 on the new coir substrate, while it was 206 and 164 on the coir substrate used for 1 and 2 years, respectively. The growth of brussel sprout was better on the coir substrate used for 3 years than that on the new coir substrate and the average number of brussel sprout leaves was 26.8 on the new coir substrate, while it was 34.3 on the coir substrate used for 3 years. The growth of Korean cabbage improved on the coir substrate used for 1 years compared to the new coir substrate and the number of leaves was 15.1 on the new coir substrate, while it was 24.3 on the coir substrate used for 1 year. Thus, used coir can be recycled to improve vegetable yields compared to using new coirs.

• 한국의류학회지
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• 제13권1호
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• pp.1-12
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• 1989

The purpose of this study was to examine the effect of basic needs and demographic variables of adult women upon clothing values. This study was designed with causal model regrading the demographic variables as independent variable: the basic need as interventing variable: the eight clothing values as dependent variables. The major findings of this research can be summarized as following; 1. Age of women has a definite effect on marriage status, school career and income. Age has effect on marriage status in seven values except exploratory value. It has effect on school career in aethetic and political values, and it has also effect on school career and income in social and religious values. 2. Age has no significant direct effect on the basic needs. Marriage status and school career have significant direct effect on the basic needs. Marriage status has positive effect on the need for self-esteem in seven values except exploratory value. The need for self-esteem of unmarried women are stronger than that of married women. School career has negative impact on the need for safety. The women having higher school career do not have strong need for safety in aethetic and social values. 3. School career, income, needs for safety, belongingness, self-esteem and self-actualizing have significant direct effect on clothing values. School career has positive effect on aethetic and political values, and it has negative effect on religious values. Income has negative effect upon social and religious values. Need for safety has negative effect on aethetic values. Need for safety is positively related with need for belongingneses, and they have an effect on the social values. Need for self-esteem has positive effect on the aethetic and political values, and it has negative impact on theoretical, economic, social and religious values. Need for self-actualizing has positive effect on the theoretical values.

• 디지털융복합연구
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• 제12권6호
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• pp.115-123
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• 2014

본 연구는 중소기업을 대상으로 첫째, 매출액순이익률, 총자산회전율 및 부채비율이 주주의 자본수익성지표인 자기자본순이익률에 어떤 영향을 미치는지, 둘째, 총자산순이익률이 자기자본순이익률에 미치는 영향관계를 부채비율이 조절하는지, 마지막으로 수정된 부채비율과 자기자본순이익률과의 영향관계를 실증적으로 분석하였다. 분석결과, 부채사용은 자기자본순이익률에 전반적으로 긍정적인 측면이 있는 것으로 나타났다. 그러나 수정된 부채비율의 2차함수 곡선모형에서 볼 수 있듯이 부채사용은 레버리지효과를 통해 자기자본순이익률의 증 감폭을 크게 확대하고 있음을 알 수 있다. 결국, 부채사용은 동전의 양면과 같이 긍정적인 측면뿐만이 아니라 부정적인 측면을 가지고 있다 할 것이다. 그래서 부채의 사용은 기존의 핵심 사업으로부터 창출되는 영업현금흐름(혹은 총자산영업이익률)으로 이자(혹은 이자율)를 커버할 수 있는 범위 내로 제한되어야 한다는 시사점을 제공하고 있다.

• 한국산업보건학회지
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• 제15권3호
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• pp.250-260
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• 2005

This study was designed to find the symptom prevalence rates of musculoskeletal disorders and the risk factors of musculoskeletal disorders among selected hair dressers. Methods; The survey were conducted from July 1 to 30, 2004 for 459 hair dressers working in Seoul and Gwangju using self-administration questionnaire. The risk factors on musculoskeletal disorders have analysed by multiple linear regression analysis. The results of this study are summarized as follows: The experience rate of musculoskeletal disorders symptom in the last one year was 56.4%. The experience rates of each body parts were 36.4% on the shoulders, 30.5% on the legs and the feet, 28.5% on the low back, 27.0% on the hand and the fingers, 23.3% on the neck and 17.0% on the arms and the elbows. The prevalence rate of musculoskeletal disorders symptom in the last one week was 40.5%, those of each body parts were 24.0% on the legs and the feet, 21.4% on the shoulders, 20.7% on the low back, 15.7% on the hand and the wrists, 15.0% on the neck, 9.4% on the arms. The risk factors on musculoskeletal disorders were working posture(${\beta}=0.32$), perceived stress(${\beta}=0.19$), working period(${\beta}=0.16$), standing working over 10 hour(${\beta}=0.16$), hard working(${\beta}=0.11$). The adjusted determinant coefficient($R^2$) of this regression model was 0.267. Based on the results, in order to prevent musculoskeletal disorders of hair dressers, working posture shall be improved and leisure opportunities to relieve stress, and health management program shall be provided.

• 한국의류학회지
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• 제31권8호
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• pp.1310-1320
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• 2007

This study investigated the differences in the importance of store characteristics depending on on-line clothing store type and consumer age. The questionnaires were given to female residents in the ages between 20-39 in Seoul and Kyung-gi province during October 2006. The results were summarized as follows: 1. By analyzing the differences in importances of on-line store characteristics factors it was found that buying process service factor and product searching system factor were important in on-line general merchandise store. and buying process service factor and product factor(all the factors, such as store credit, product, screen-displayed design, searching and approaching system, customer management service) were important in on-line specialty store. 2. By analyzing the differences in importances of on-line store characteristics depending on the store type, buying process system such as refund policy, shipping, high-speed payment and rapid searching, screen-displayed design system, approaching and searching system were more important in on-line general merchandise store when comparing to specialty store. It also showed that the consumer considered the reputation of the store and its image more important in on-line general merchandise store. 3. By analyzing the differences in of on-line clothing store importance depending on age, in the case of on-line general merchandise store, it showed that people in their thirties regarded buying process service factor more important than twenties, and when it came to the product and searching system, it was vice versa. Twenties had a tendency to consider the aspect of product important and, relatively, thirties regarded searching and approaching system factor important. in the case of specialty store. It was found that women in their twenties had a tendency to consider product factor more important.

• 한국가정과교육학회지
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• 제5권1호
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• pp.113-120
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• 1993

This study in order to seek for a more effective teaching method, I am to propose a measure that the career education material for female middle school students a program produced already could be applicable on the class and to understand the efficiency by examining practically it to the student. The research method was to make up a questionnaire and gaze two kinds of educational effect. The procedure was that, after surveying the general features in order to help them known their consciousness on the career education Researcher practiced common theorectical teaching on comparative class and moduling teaching on comparative class through making a guiding data. Then Researcher analysed the changing o consciousness on career, knowledge on kinds and numbers of jobs, and the results and rate of interest in the teaching with persentage and t-test. The results are as followed; First, on the consciousness on career, both group showed little change on their wishful job between before and after teaching. On the purpose to get a job, consciousness on work and job, and fixed idea of job on gender, there were some changes, but both groups had few defferences in the changing rate. Second on the consciousness on work and job experimental group recognized the variety of job more than comparative group and wrote more hind of job. Third on the evaluating result, the record of experimental group was higher. Fourth, on the rate of interesting in learning the rate of experimental group was higher. As observed the class applied by the module of female career education is effective, since experimental group showed more consciousness on work and job, evaluation of record after teaching and the rat of interesting in learning, through there was no difference in the consciousness of the career.