• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 A
• /
• pp.241-243
• /
• 1999

This paper describes a series of experiments investigating the operational characteristics of high-Tc superconducting synchronous motor of five to six hundred watts capacity. In this experiment, ac 220V stator phase voltage and DC 4A excitation current are used, and the synchronous speed runs at 1800rpm. Hall Sensors are installed on the pole face and at the side of the Ag/Bi-2223 high-Tc superconducting tape in order to analyze the effect of the time-varying magnetic field on the motor performance when the load changes its value. The experimental observations are compared with the theoretical predictions.

• 아동학회지
• /
• 제25권6호
• /
• pp.117-130
• /
• 2004

The purpose of this study was to investigate the association between educational beliefs and teaching efficacy of early childhood teachers. The subjects were 291 early childhood teachers in Gwangju City and Jeonnam Province. The research showed that teachers' educational beliefs were significantly associated with teaching efficacy for the teachers who have more than five-year-teaching career. In addition, teachers who had maturational educational belief showed higher scores in general teaching efficacy throughout all educational level. Moreover, teachers who had maturational educational belief and interactional educational belief showed higher teaching efficacy scores in public and private kindergartens and private childcare centers.

• 아동학회지
• /
• 제25권6호
• /
• pp.105-115
• /
• 2004

The 60 subjects of this study were 3rd, and 6th grade elementary and undergraduate university students. The instrument of 44 items had two typical and two atypical exemplars from 11 semantic categories. Each subject was exposed individually to the word list and asked to categorize each item. At test, subjects generated five items that came to mind in each category. Data was analyzed by 2-way ANOVA, age (3) $\times$ category of typicality (2). All main effects and the interaction effect between age and typicality were significant. There were no significant differences among age groups on typical lists while significant differences between university and elementary school students (Grades 3 and 6) were found on atypical lists. Thus, the knowledge base might be an important factor in implicit memory.

• Korean Journal of Acupuncture
• /
• 제23권3호
• /
• pp.1-15
• /
• 2006

Objectives : The aim of this study was to analyze the symptoms of a disease and to elucidate the meaning and rationale of point selection in YuLongFu. Methods : We translated YuLongFu into Korean and analyzed symptoms based upon a comparison of YuLongFu with YuLongGe. The meaning and rationale of point selection in YuLongFu was then inferred from the analysis above. Results and Conclusions : Total 46 points (6 points were repeated) were used in YuLongFu. These points included the collateral Meridian, the four seas, five shu points, lower confluent points, yuan points and eight influential points. Moxibustion and pricking blood therapy were used twice. Generally, threre are a lot of diseases caused by stagnation of Qi and blood in YuLongFu. Point selection, therefore, was usually aimed at promoting flow of Qi and blood.

• Journal of Microbiology
• /
• 제33권4호
• /
• pp.344-349
• /
• 1995

The alkalophilic bacterium, Xanthomonas sp. JK311, producing extracellular proteases, was isolated from soil. Xanthomonas sp. JK311 produced five extracellular proteases that are all metalloproteases. Four of them were resistant against 1% SDS. Chromosomal DNA of the Xanthomonas sp. JK311 was digested with BamHI and cloned into PUC19. Among E. coli strain HB101 transformants, a clone secreting the proteases was screened through halo formation on skim-milk agar plate and by Southern blot analysis. It had the recombinant plasmid pXEP-1 containing the 7.5 kb-BamHI DNA fragment and produced three extacellular proteases. Their protease properties corresponded to those of Xanthomonas sp. JK311.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
• /
• pp.337-340
• /
• 2003

This paper describes the operational characteristics of protection algorithm applied in distributed generations(DG) for faults occurred in the interconnected distribution networks. The DG can be Influenced by abnormal grid conditions such as disturbances occurring in the neighboring distribution feeders as well as the interconnected power line. Particularly, in case of the fault happening in the neighboring distribution feeders emanated from the substation to which DG is connected, the protective devices in the DG might mis-operate. The mis-operation of protective devices can be varied by the fault conditions. The simulation results for Hoenggye substation model composed of five feeders using PSCAD/EMTDC showed that the number of mis-operation of protective devices applied in DG is about 0.66 times per one year.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
• /
• pp.33-35
• /
• 1994

This Paper Presents a practical approach to evaluate the reliability indices of electric distribution systems. The use of reliability evaluation is placed with the framework of distribution system planning. In this paper, the reliability model is based on an analytical method, connecting component failure to load point outage each section. five case studies are reported in the paper. These are to study the effect of varying failure rates and repair times on distribution feeders. The results of a study on sample system are presented in this paper.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 2000년도 제32회 추계학술대회 정기총회
• /
• pp.318-331
• /
• 2000

Electrical and tribological behaviours of a copper-graphite brush in a slipring-brush assembly were investigated to evaluate the characteristics of electric signal transmission between a slipring and a brush. Five brush materials containing different amounts of copper and graphite were studied. The result showed that a copper-graphite brush at a particular graphite content exhibited the most stable frictional and electrical behaviour suggesting an optimum amount of a solid lubricant in a metal-graphite brush system. Microscopic observation and the surface analysis showed good agreements with this phenomena. In addition, the deviation of the friction coefficient and electric signal distortion has a close relationship with a microscopic mechanical vibration and the change of a real contact area.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2008년도 춘계학술대회 논문집
• /
• pp.79-83
• /
• 2008

We carry out three-dimensional simulation of pore closing processes during upsetting in open die forging. Several pores on a plane section of a cylindrical material are traced at the same time and the results of hydrostatic pressure and effective strain are discussed to reveal the parameters affecting pore closing phenomena. Five different sizes of pores are also investigated by simulation to reveal the pore size effect in pore closing during upsetting. AFDEX 3D is employed for this study.

• 대한수의학회지
• /
• 제11권1호
• /
• pp.91-95
• /
• 1971

During three months from December 1967 to February 1968, 1867 Korean native cows slaughtered in pusan abattoir were investigated for studying the incidence of cystic ovaries. The results obtained in this experiment are summarized as follows: 1. The average frequency of cystic ovaries in 1867 Korean cows was 17 cases, or 0.91%. 2. In 17 cases 1, or 0.3%, occurred in cattle from 1 to 3 years of age; 4 or, 1.02% in four; 7 or, 2.02% in five; 2 or, 0.63% in six; and 3, or 0.63% occurred between 7 and 9 years of age. 3. The incidence of cysts in the respective ovaries, the left ovary was cystic in 23.5% of the cases, the right one in 41.2% and both ovaries in 35.3%. 4. According to the histological findings of cystic ovaries, follicular cysts were 88.2% and luteal cysts 11.8%.