• 한국농공학회지
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• 제21권2호
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• pp.81-103
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• 1979

The weathered granite soil involves problems in its stability in soil structures depending upon the reduction of soil strength due to the water absorption, crushability, and content of colored mineral and feldspar. As an attemt to solve the problems associated with soil stability, the crushability of weathered granite soil was investigated by conducting tests such as compaction test, CBR test, unconfined compression test, direct shear test, triaxial compression test, and permeability test on the five soil samples different in weathering and mineral compositions. The experimental results are summarized as follows: The ratio of increasing dry density in the weathered granite soil was high as the compaction energy was low, while it was low as the compaction energy was increased. The unconfined compressive strength. and CBR value were highest in the dry side rather than in the soil with the optimum moisture content, when the soil was compacted by adjusting water content. However, the unconfined compressive strength of smples, which were compacted and oven dried, were highest in the wet side rather than in soil with the optimum moisture content. As the soil becomes coarse grain, the ratio of specific surface area increased due to increased crushability, and the increasing ratio of the specific surface area decreased as the compaction energy was increased. The highest ratio of grain crushability was attained in the wet side rather than in the soil with the optimum moisture content. Such tendency was transforming to the dry side as the compaction energy was increased. The effect of water on the grain crushability of soil was high in the coarse grained soil. The specific surface area of WK soil sample, when compacted under the condition of air dried and under the optimum moisture content, was constant regardless of the compaction energy. When the weathered granite soil and river sand with the same grain size were compacted with low compaction energy, the weathered granite soil with crushability had higher dry density than river sand. However, when the compaction energy reached to certain point over limitation, the river sand had higher dry density than the weathered granite soil. The coefficient of permeability was lowest in the wet side rather than in the optimum moisture content, when the soil was compacted by adjusting soil water content. The reduction of permeability of soil due to the compaction was more apparent in the weathered granite soil than in the river sand. The highly significant correlation coefficient was obtained between the amount of particle breakage and dry density of the compacted soil.

• 지질공학
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• 제30권2호
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• pp.161-173
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• 2020

본 연구는 세계지질공원인 무등산국립공원 내 주상절리대의 공학적 특성을 살펴보고 위한 것으로서, 대상 암석인 무등산응회암의 물리·역학적 성질 파악, 주상절리 풍화정도 산정, 그리고 주상절리 내 균열거동 모니터링 등을 실시하였다. 무등산응회암의 물리적 성질은 평균 공극률의 경우 1.02%, 평균 흡수율은 0.38%, 평균 비중은 2.69 g/㎤, 그리고 평균 종파속도는 4,948 m/s로 나타났다. 역학적 성질의 경우 평균 일축압축강도는 337 MPa, 평균 탄성계수는 68 GPa, 평균 포아송비는 0.29, 평균 점착력은 41.3 MPa, 평균 마찰각은 62.8°로 나타났다. 실버슈미트해머 평균 반발경도 Q값은 49.3이며, 이를 일축압축강도로 환산하면 70.5 MPa로 신선한 일축압축강도의 약 21%에 해당되었다. 그리고 입석대 주상절리 3개 블록에 대한 균열 모니터링 측정 결과, 균열 거동은 블록 모두에서 1 mm 이하로 나타나 주상절리 내 균열 거동은 현재까지 거의 발생하지 않은 것으로 판단된다.

• 한국조리학회지
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• 제20권4호
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• pp.127-143
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• 2014

본 연구에서는 기능성 물질이 함유된 유색보리와 유색보리 분말을 첨가한 식빵 반죽 및 식빵을 제조하여 이화학적, 관능적 특성을 첨가량을 달리하여 측정하였다. 유색보리 분말의 수분함량은 9.35%, 조단백은 9.37%, 조지방은 1.64%, 조회분은 2.96%로 나타났다. 수용성 식이섬유 함량은 3.21 g/100 g, 불용성 식이섬유 함량은 4.91 g/100 g, 총 식이섬유 함량은 8.12 g/100 g으로 나타났고, ${\beta}$-glucan 함량은 49.31 mg/g으로 나타났다. DPPH radical 소거능은 56.76%로 나타났고, 총 페놀 함량은 234.34 mg/100g으로 나타났다. 유색보리 분말을 첨가한 식빵 반죽의 farinograph 측정 결과 consistency, water absorption, development time, time breakdown은 첨가량이 증가할수록 감소하였고, tolerance index는 첨가량이 증가할수록 증가하였다. Alveogram 측정 결과 overpressure P값, extensibility L값, swelling index G값, deformation energy W값은 첨가량이 증가할수록 감소하였다. Amylograph 측정 결과 pasting temp. T값은 첨가량이 증가할수록 증가하였고, peak viscosity P값, hot past viscosity H값, breakdown P-H값은 첨가량이 증가할수록 감소하였다. 유색보리 분말을 첨가한 식빵의 굽기 손실률, 비용적은 첨가량이 증가할수록 감소하였다. 색도 L값, b값은 첨가량이 증가할수록 감소하였고, a값은 첨가량이 증가할수록 증가하였다. 유색보리 분말 첨가한 식빵의 texture 경도, 점착성은 첨가량이 증가할수록 증가하였고, 응집성, 탄력성, 씹힘성은 첨가량이 증가할수록 감소하였다. 기호도는 맛, 부드러움, 씹힘성은 10% 첨가군이 높게 나타났고, 전반적인 기호도도 10% 첨가군이 5.04로 가장 높게 나타났다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.58-60
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• 2007

Magnetic Resonance Imaging(MRI) has become a very widely used medical procedur e. Clo.sed and open systems are typically used with static magnetic fields at or below 2 Tesla. BWhole body SAR(specific absorbsion rate) is the value of SAR averaged over the entire body of the patient over any period of 15 minutes. Head SAR is the value of SAR averaged over the head of the patient for any period of 10 minutes. SAR is a measure of the absorption of electromagnetic energy in the body' (typically in watts per kilogram (W/kg)). The normal operating mode comprises values of head SAR not higher than 3 W/kg. The second level controlled operating mode comprises values higher than 3 W/kg. Current FDA guidance limits the SAR in the whole body. including the head to a range of 1.5 to 4.0 W/kg, depending on the patient's clinical condition. SAR, limit restrictions are incorporated in all MRI systems. and domestic' s guidance limits the SAR in a part body. including the head to 3.2w/kg and less. The purpose of this study is to evaluate on change of head SAR in using MRI pulse sequence and to check if exceed 3.2(w/kg) level in domestic a part exposure through measured head SAR. 23 patient's the average head SAR of pulse sequence is that T2WI sagittal is 0.5375. T2WI axial(FSE) is 0.4817, T1WI axial(SE) is, 0.8179. FLAIR axial is 0.4580. GRE axial is 0.0077, Diffusion is 0.0824w/kg. The head SAR exposed per patient was proved 2.3845w/kg less than the international standard. Coefficient of correlation for the relations body weight and SAR or for the relations ETL(echo train length) and SAR is 1 value. Coefficient of correlation for the relations between TR(time to repeat) and SAR is -0.602 value. so SAR increased relative to weight body and ETL. But the relations between TR and SAR is negative definite.

• 한국식품과학회지
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• 제12권4호
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• pp.292-298
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• 1980

대두식품(大豆食品)으로 단백질(蛋白質)이 주성분(主成分)인 두부의 저장성(貯藏性)을 높이기 위(爲)한 기초연구(基礎硏究)로서, 두부를 열풍건조(熱風乾燥) 및 냉동(冷凍) 건조분말(乾燥粉末)로 하여 일정(一定)한 상대습도(相對濕度)에 방치(放置)하였을 때의 수분흡착특성(水分吸着特性)과 곰팡이 발생(發生) 등(等)에 관(關)해 구명(究明)한 바, 그 결과(結果)는 다음과 같다. 1. 수분함량(水分含量)이 85%인 생(生)두부를 열풍건조기(熱風乾燥機)를 이용(利用)하여 $55^{\circ}C$에서 2cm 두께로, 건조(乾燥)할 때에 수분함량(水分含量)을 건물중(乾物重) 8.8%까지 내리는데 18시간(時間)소요(所要)됐으며, 수분함량(水分含量) 감소율(減少率)은 5시간(時間)까지는 급속(急速)히 감소(減少)되다가 차츰 완만(緩慢)하였다. 2. 수분흡착시(水分吸着時) 온도(溫度)가 높을수록 평형수분함량(平衡水分含量)은 낮았고, 냉동건조(冷凍乾燥) 분말(粉末)두부의 경우(境遇) 열풍건조(熱風乾燥) 분말(粉末)두부보다 높았으며 입자(粒子)의 크기는 수분흡착(水分吸着)에 큰 영향(影響)을 미치지 않았다. 3. 단분자층(單分子層) 수분함량(水分含量)은 평형수분함량(平衡水分含量)이 큰 냉동건조(冷凍乾燥) 분말(粉末)두부가 8.3%로 가장 높았다. 4. 수분흡착(水分吸着)에 요(要)하는 자유(自由)에너지는 상대습도(相對濕度) 11%, $15^{\circ}C$에서 1,285.1 cal/mole, $30^{\circ}C$에서 1,323.5 cal/mole로 38.4 cal/mole이 낮았으며 냉동건조(冷凍乾燥) 분말(粉末)두부의 흡착(吸着)에 필요(必要)로 하는 자유(自由)에너지가 열풍건조(熱風乾燥)에 의(依)한 것보다 낮았다. 5. 입자(粒子)의 크기가 흡습속도(吸濕速度)에서는 영향(影響)을 주지 않았고 온도(溫度)가 높을수록 상수(常數)가 낮아지는 경향(傾向)을 나타냈으며, 냉동건조(冷凍乾燥) 분말(粉末)두부의 경우(境遇), $15^{\circ}C$에서 0.00804, $30^{\circ}C$에서 0.00696이었다.