• Proceedings of the KSEE Conference
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• 2008.10a
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• pp.17-28
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• 2008

국책사업이나 SOC의 확충을 위한 도로 및 철도의 건설에서 적용되는 터널의 단면크기를 보면, $50m^2$에서부터 $100m^2$이상의 중 대단면 터널이 주를 이루고 있으나, 전력구, 통신구, 소규모로 운영되는 광산의 채광용 터널, 용수를 위한 도수로터널 등 특수한 용도로 설계, 시공되고 있는 터널에서는 $20m^2$이하의 단면크기를 갖는 경우가 있다. 이러한 소단면 터널의 경우에는 협소한 작업공간으로 인하여 적용공법 뿐만 아니라 장비의 사용 또한 제약을 받게 되어 작업효율이 저하되고 공사기간이 늘어나게 되는 등 여러 가지 문제점을 안고 있다. 특히, 에멀젼 폭약을 사용하는 발파에서 먼저 기폭된 발파공의 충격압력에 의해 인접공의 폭약이 예비압축(Precompression)되어 사압현상을 일으키고 잔류약을 발생시키는 사례가 종종 발생하고 있다. 사압현상은 당해 발파의 실패와 함께 2차적인 사고의 위험요인이 될 수 있으므로 이를 방지하기 위한 대책을 수립하여야 한다. 이를 위해 기존 문헌을 통하여 사압현상의 원인과 발생 가능성을 검토하였고, 국내에서 주로 사용되는 에멀전폭약의 수중 내충격성시험과 충격압력 전달시험을 실시하여 사압현상의 발생정도를 측정하였으며, 사압현상이 발생한 소단면 터널현장을 대상으로 대책을 수립하여 적용하였다. 심발방법을 변경하여 전단의 충격압력을 견딜 수 있는 공간격을 확보하고 뇌관의 초시간격을 적절하게 배치한 발파패턴을 적용한결과, 사압현상을 억제하고 잔류약의 발생을 감소시켜 계획 굴진장을 확보하고 파쇄석의 크기를 감소시키는 등 양호한 결과를 얻을 수 있었다.

• The Journal of Engineering Geology
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• v.15 no.4 s.42
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• pp.463-473
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• 2005

Because of using the same rating ranges for every rock types the RMR or the Q-system could not usually consider local geological characteristics They also could not present sufficiently the engineering anisotropy of rocks. The canonical correlation analysis was carried out with 3 kinds of face mapping data obtained from granite, sedimentary rock and phyllite in order to clarify a discrepancy between rock types. According to analysis results, as a type of rocks changes, RM factors have different influences on the total rating of RMR.

• Journal of Engineering Education Research
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• v.13 no.6
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• pp.164-170
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• 2010

This article explores the effects of the RBI(Robot Based Instruction) for promotion of students' interaction in elementary school. It was found that Cognitive Affective Metacognitive interaction is evenly spread in RBI. It was particularly high the ratio of metacognitive interaction. According to the analysis result of learner's activity by the detailing, it was observed that robot media promoted students' interaction. Also, metacognitive interaction about clarification and elaboration was promoted lively in the RBI situation. Therefore, RBI was helpful to promote of students' interaction in elementary school.

• Journal of Environmental Impact Assessment
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• v.18 no.1
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• pp.1-9
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• 2009

Even though the center of Cheongju city needs redevelopment because of a doughnut phenomenon, it has to be permitted within the environmental carrying capacity like a target water quality proposed on the Total maximum daily loads(TMDL) of Musim and Miho river watersheds. The aim of in this study is to identify the limit of redeveloping Cheongju downtown after analyzing its environmental carrying capacity using QUAL2E model. As a result of modeling various scenarios, the water quality of Musin river was shown that $BOD_5$ is 2.3mg/L which is the target water quality in the double of existing development plan of the Cheongju downtown. The water quality of Miho river was $BOD_5$ 3.97mg/L which is less than the target water quality of Miho B watershed in the same condition. Therefore, this means that the limit of redevelopment within the environmental carrying capacity of cheongju downtown was estimated to be the double of existing development plan.

• Applied Microscopy
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• v.27 no.4
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• pp.391-402
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• 1997

Using the electron microscopical method, this study was attempted to investigate the ultrastructural characteristics of glomeruli in FGS/Kist mice showing high proteinuria. The mucus-like substances were observed in glomerular capillary lumen which were usually narrowed by the widening of mesangial area filled with electron-dense deposits. Some portions of basal lamina in capillary wall were projecting to urinary space. Moreover, many vacuoles were observed in the cytoplasm of visceral epithelial cells, and an irregular-shaped fusion or effacement of foot processes were often shown in areas adjacent to basal lamina of glomeruli.

• Journal of Sensor Science and Technology
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• v.8 no.4
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• pp.308-313
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• 1999

This paper will present an anisotropic etching in TMAH technique used in the fabrication of three-dimensional magnetic field vector sensor based on angled Hall plate structure. This sensor design relies on simultaneously detecting all magnetic field vector components using Hall plates that are imbedded into the silicon [111] sloped-surface of bulk micromachined cavity by the anisotropic etching of [100] silicon. The fabricated Hall elements has relatively improved sensitivity compare to convensional Hall elements for three-dimensional magnetic field sensing. The product sensitivity of 547V/AT at the supply current of 1.0mA was achived. The corresponding limit in the detection of magnrtic field is 0.07G that calculated by measured power spectral density(PSD) in magnetic sensor output.

• Applied Microscopy
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• v.39 no.1
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• pp.73-77
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• 2009

Contaminative artifacts such as carbonaceous materials on carbon-coated microgrids are unavoidable, which is induced by electron beam exposure inside electron microscopes. This phenomenon raise a source to produce confusing information to the samples investigated by analytical TEM, which should be alleviated as much as possible. As experimental precautions for reducing this unwanted effect, the use of $LN_2$ cooled anti-contaminator and pre-illumination of electron beam at low magnification can be helpful. Nevertheless, we should be cautious to set an illumination condition for microanalysis because the contaminative effect is dependent with the types of irradiation situations, which is well known to be a decisive factor for causing the carbonaceous artifacts. Accordingly, it is necessary that optimal illumination to minimize the contaminative effect should be selected for improving the accuracy of microanalysis. In this paper, we introduce the practical method to determine the optimal illumination condition by evaluating the contaminative effect as a function of instrumental spot size, which is directly linked with electron current density.

• School Mathematics
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• v.6 no.2
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• pp.181-211
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• 2004

Recently, there are many countries which have tried to renew mathematics curriculum in the world. The study aims to induce useful implications for improving our mathematics curriculum through reflections on revised mathematics curriculums in many countries. In order to attain these purposes, the present paper reflects systems and contents of mathematics curriculum of Germany, which is not well known to us in spite of old mathematical tradition including Klein's theory for mathematics education. But there are inherent mathematics curriculum for each state in Germany Therefore this paper analyzes mathematics curriculum in state Nordrhein-Westfalen. Under these analyses, implications for our mathematics curriculum are discussed.

• Journal of Embryo Transfer
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• v.21 no.1
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• pp.1-5
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• 2006

본 연구는 개 채취 정액의 동결후의 생존성과 신선 및 동결 정자의 capacitation, acrosome reaction과 생존성을 조사하고, 아울러 신선 및 동결 정액을 자연 발정 또는 발정 유기 암캐 에게 인공수정 후 임신율을 조사하였다. 개 채취 정액의 동결 융해 후의 생존성은 $64.5{\pm}2.30%$로서 신선 정액의 생존성에 비해 유의하게 낮게 나타났다(p<0.05). 신선 및 동결 정액의 capacitation, acrosome reaction 및 생존성은 각각 $52.5{\pm}4.5%,\;9.5{\pm}0.6%,\;68.8{\pm}4.5%$ 및 $16.2{\pm}3.2%,\;3.2{\pm}0.5%,\;24.5{\pm}2.5%$로 나타났다. 신선 및 동결 정액을 자연 발정 또는 발정을 유기한 암캐에 인공수정했을 때 임신율은 각각 50.0% 및 33.3%로서 동결 정액을 이용했을 때 임신율이 신선 정액에 비해 낮은 임신율을 나타냈다.

• School Mathematics
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• v.14 no.2
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• pp.233-253
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• 2012

The purpose of the study investigate mathematics content knowledge(MCK) of prospective teachers in differential area. 70 prospective teachers were asked to perform six questions based on Cho's MCK (2010, 2011). The results show that depending on whether they experience any teacher education program, the level of prospective teachers' mathematics content knowledge may vary. In particular, prospective teachers struggled with an unfamiliar problem situations. We also found that prospective mathematics teachers have some difficulty in solving problem about the use of mean value theorem and derivative.