• Journal of the Korean Geotechnical Society
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• v.16 no.5
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• pp.149-155
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• 2000

응답변위법에서 이용되는 동지반강성계수의 적절한 평가법에 대한 제안을 하였다. 현재까지의 지진피해조사 및 장기간의 지진관측사례는 지반이 공진할 때의 변형모드가 지중구조물의 피해에 가장 직접적으로 관련이 있는 것으로 알려져 있다. 따라서, 지중구조물의 축방향의 지반의 변형모드와 그 타월 진동수를 특정하여 동지반강성계수를 평가했다. 동지반강성계수는 지반의 공진상태를 상정하고 있기 때문에 결과로써 지진파의 축방행 파장의 영향을 받지 않고, 관상구주물의 반경과 표층두께의 비, 표층두께에 대한 구조물의 매설위치, 표층지반과 기반의 임피단스비 라고 하는 3개의 무차원 변수에 의해 표현된다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.10a
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• pp.522-526
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• 1998

본 논문은 가정용 배전반 시스템을 디지털식으로 구현하고, 기존의 디지털식 배전반 시스템에 없는 월 수요전력량 예측과 화재발생의 원인 중에 하나인 옥내 전선선로의 결함을 신경회로망으로 검출하여 차단하는 인공지능형 가정용 배전반 시스템을 하드웨어로 구현하고 실험하였으며, 그 결과를 제시하였다.

• Animal Systematics, Evolution and Diversity
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• v.14 no.2
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• pp.99-103
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• 1998

A new species, Osorius mujechinensis, is described based on SEM microphotographys of the extenal structures and illustrations of the aedeagus. This new species was collected at Mujechi Moor, Mt. Chongjoksan, Ulsan, Korea. The subfamily Osoriinae in Korea now comprises two recorded species of the genus Osorius.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.97.1-97.1
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• 2010

유연금속기판위에 DC 마그네트론 스퍼터링을 이용하여 Ag/ZnO 이중구조의 후면반사막을 증착하고 Ag 표면조도 변화에 따른 후면반사막의 반사특성 변화와 플렉서블 비정질 실리콘 박막 태양전지의 셀 특성에 미치는 영향을 조사하였다. Substrate구조를 갖는 플렉서블 실리콘 박막 태양전지에서는 실리콘 박막 광흡수층의 상대적으로 낮은 광 흡수율로 인하여 입사광에 대한 태양전지 내에서의 광 산란 및 포획이 태양전지 효율을 증대시키는데 매우 중요한 역할을 하는 것으로 알려져 있다. 플렉서블 실리콘 박막 태양전지에서의 후면반사막은 광 흡수층에서 흡수되지 않는 입사광을 다시 반사시켜 광 흡수를 증대시키며 이때 후면반사막 표면에서 반사 빛을 효율적으로 산란시켜 이동경로를 증대시킴으로써 광 흡수율을 더욱 향상시킬 수 있다. 본 연구에서는 유연금속 기판위에 Ag와 ZnO:Al($Al_2O_3$ 2.5wt%) 타겟을 사용한 DC 마그네트론 스퍼터링법으로 Ag/AZO 이중구조의 후면반사막을 제조하고, Ag 박막의 표면형상 변화와 이에 따른 후면반사막의 반사도 변화를 비교, 분석하였다. 증착 조건 변화에 따른 표면 형상 및 반사 특성은 Atomic Force Mircroscope(AFM), Scanning electron miroscopy(SEM), UV-visible-nIR spectrometry를 통하여 분석하였다. 서로 다른 표면 거칠기를 갖는 후면반사막 위에 n-i-p구조의 a-Si:H 실리콘 박막 태양전지를 제조한 후 태양전지 동작 특성에 미치는 영향을 조사하였다. n,p층은 13.56MHz PECVD, i층은 60MHz VHF CVD를 사용하여 각각 제조 하였으며, Photo I-V, External Quantum Efficiency(EQE) 분석을 통하여 태양전지 특성을 조사 하였다. SEM 분석결과 공정 온도가 증가 할수록 Ag 박막의 표면 결정립 크기도 증가하였으며, AFM분석을 통한 Root-mean-square(Rms)값은 상온에서 $500^{\circ}C$로 증착온도가 증가함에 따라 6.62nm에서 46.64nm까지 증가하였다. Ag 박막의 표면 거칠기 증가에 따라 후면반 사막의 확산 반사도도 함께 증가하였다. 공정온도 $500^{\circ}C$에서 증착된 후면반사막을 사용하여 a-Si:H 태양전지를 제조하였을 때 상온에서 제조한 후면반사막에 비하여 단락전류밀도 (Jsc)값은 9.94mA/$cm^2$에서 13.36mA/$cm^2$로 증가하였으며, 7.6%의 가장 높은 태양전지 효율을 나타내었다.

• Journal of The Korean Association For Science Education
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• v.21 no.1
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• pp.22-29
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• 2001

The purpose of this study is to investigate the effects of lessons adopting portfolio assessment regarding feedback on elementary school student's scientific knowledges, inquiry abilities and their perceptions of it. For this study, two classes of 5th grade elementary school in suburb were selected. As an experimental group, one class was selected to apply the lessons adopting portfolio assessment regarding feedback, and the other class as a control group was selected to apply the lessons adopting portfolio assessment without feedback. The investigator taught and assessed both group students. The results showed a significant difference in scientific knowledge between the experimental group and the control group (p<.05). More detailed analysis of scientific knowledge found that the feedback effect was statistically positive in the memory and the understanding domain, but there was no effect in the application domain. No statistical difference was identified in inquiry abilities. The results of the questionnaire on the perceptions of portfolio assessment showed that students of the experimental group had higher positive responses on the 'perception about the effects of lesson' and on the 'perception in scientific attitudes' than the control group. However, the control group students had higher positive responses on the 'perception about self-evaluate of their own portfolio' and the 'perception about need of feedback' than the experimental group.

• Korean Journal of Childcare and Education
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• v.10 no.6
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• pp.57-80
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• 2014

The purpose of this study was to analyze the relationship between an infant teachers' efficacy and job stress by demographic variables to provide the data for improving job conditions and teacher education. For this study, teachers who work in the childcare center located in Gyeongsangbukdo participated in a survey. The questionnaire was distributed from March 11. 2013 to March 29. 2013. The results were as follows; first, an infant class childcare teachers' efficacy was above average and general efficacy was higher than personal efficacy. There were significant differences in personal variable(age, marital status) and working condition(the type of facility, average working hours, average wage, the number of children). Second, an infant class childcare teachers' job stress was above average and that depended on the economy, the infant's parents, work, infant, individual, administration, and co-workers in decreasing order of influence. The job stress was significant differences in personal variable(age, martial status, experience, number of completed training) and working variable(the type of facility, average working hours, the number of children, average wage). These results indicate that improvement in the infant class childcare teachers' efficacy is more important than anything else in promoting their job conditions.

• LOGISTICS
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• s.11
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• pp.47-47
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• 2005

• Product Safety
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• s.82
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• pp.44-47
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• 2000

• 대학교육
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• s.129
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• pp.118-121
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• 2004

• Korean Chemical Engineering Research
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• v.52 no.5
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• pp.672-677
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• 2014

Torrefaction is a thermal treatment process to pre-treat biomass at temperature of $200{\sim}300^{\circ}C$ under an inert atmosphere. It was known that torrefaction process strongly depended on the decomposition temperature of the lignocellulosic constituents in biomass. In this work, the torrefaction characteristics of baggase has been studied. This study focuses on the relation between the energy yields, heating values, gas emission, volatile and ash constituents with torrefaction temperatures and times. The activation energies of baggase torrefaction has been studied by using TGA (Thermogravimetric Analyzer). From this work, it was seen that ash constituents and heating values were increased with torrefaction temperature, while volatile constituents and energy yields decreased. It was also found that carbon monoxide containing oxygen were decomposed at a lower temperature than those of hydrocarbon compounds, $C_xH_y$.