플라이애쉬를 이용한 강우시 비탈면의 안정성 평가

이강일,최태식,박민지,최윤석 한국재난정보학회 2018 한국재난정보학회 학술대회 Vol.2018 No.11

국내에서는 1963년부터 1996년까지 강우로 인해 20명 이상이 사망한 대규모 비탈면 붕괴가 15건이 발생 하였으며, 2003년에는 집중호우를 동반한 태풍 매미에 의해 전국적으로 196개소의 비탈면 붕괴가 발생되었 다. 또한 1990년대에는 자연재해로 140명의 인명피해가 발생하고, 그중 산사태에 의한 피해가 16%인 22.7 명으로 보고된 바 있다. 특히 2002년 태풍 루사로 인해 56명에 이르는 인명피해가 발생하여 강우로 인한 비탈면 붕괴 양상이 심각해지고 있는 것을 알 수 있다. 이러한 비탈면 붕괴사례를 볼 때, 비탈면 붕괴는 주로 강우가 내리는 동안 발생하고, 그 원인은 강우가 간극이 크고, 강도가 작은 토층내로 침투하여 안정 상태를 유지하고 있는 토층에 외력을 작용시키기 때문이다. 이러한 비탈면 파괴에 대한 연구들은 주로 강 우 시 불포화토의 거동에 관한 연구는 활발하게 진행되고 있는 반면, 세굴 및 침식에 의한 비탈면 파괴에 대한 연구는 매우 미미한 실정이다. 따라서 본 연구는 강우시 세굴 및 침식에 순응이 가능하면서 표면식생 이 가능한 친환경적인 비탈면 개량재인 엔쏘일(N-Soil) 표층제품을 대상으로 물리적, 역학적 특성을 변화 시켜 강우 모형시험을 실시하였다. 이를 통해 강우로 인한 세굴 및 침식에 근본적으로 대응할 수 있는 새 로운 비탈면보호공법의 개발 및 검증에 그 목적을 두었다.

水晶體 β-Crystallin의 Carboxylmethylation에 關한 硏究

李康一,郭相太,林圭 충남대학교 의과대학 지역사회의학연구소 1988 충남의대잡지 Vol.15 No.2

Changes of protein patterns of nonmethylated and endogenous or exogenous methylated β-crystallin fractions have been investigated, and then the methyl-acceptor proteins identified by urea /polyacrylamide gel electrophoresis. 1. Nonmethylated β_H and β_L-crystallin were separated in ten, eleven fractions, respectively. In the endogenous methylated β_H-crystallin, subfraction No. 10 was disappeared and No.3 was increased when compared with that of nonmethylated. In the β_L-cryallin, subfraction No.8, 10, 11 were decreased and No.6, 7 was increased. 2. When native β-crystallins were electrophoresed, subfraction No. 7, 9 disappeared and No.8b, 10b were newly appeared and. No. 6 was increased in methylated β_H-crystallin, and subfraction No. 11 was disappeared, No.9 was decreased and No.8 was increased in meth ylated β_L-crystallin. But, subfraction profile of methylted a-crystallin was not changed. 3. Methyl-acceptor proteins in each crystallin were subfraction No. 1, 6, 8 in a-crystallin, 2, 3, 6, l0a in β_H-crystallin and 1, 6, 7, 8, 10 in β_L-crystallin, respectively. These results suggest that the effect of carboxylmethylation on the aggregation of β-crystallin is related to not only the interaction of a, r-crystallin subfractions, but also the interaction of β-crystallin subfractions. On the other hand, a-crystallin is only related to the interaction of the other crystallin subfractions.

Dependencies of Acoustic Properties on the Frequency, Porosity, and Grain Size in Water-Saturated Sandy Sediment from 150 to 350 kHz: Application of the Grain-Shearing Model

이강일 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.1

In the present study, the grain-shearing (GS) model for wave propagation in a saturated, unconsolidated,granular material was applied to predict the dependencies of the acoustic properties, such as the phase velocity and the attenuation, of the compressional wave on the frequency, porosity,and grain size in water-saturated sandy sediment over the frequency range from 150 to 350 kHz. The GS model predicted a slightly positive velocity dispersion and a near-linear relationship of the attenuation with the frequency, following well the trends of the data acquired from water-saturated sandy sediment with a porosity of 0.408 and a mean grain diameter of 425 µm. The predictions for the relationships of the acoustic properties with the porosity and the grain size also showed good agreement with the measurements. These results suggest that the GS model may be usefully employed as a practical tool for estimating the acoustic and the physical properties of a sediment.

Frequency Dependencies of Acoustic Properties in Water-Saturated Sandy Sediment from 0.5 to 1.0 MHz: Application of the Modified Biot-Attenborough Model

이강일 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.6

In the present study, the modified Biot-Attenborough (MBA) model for acoustic wave propagation in fluid-saturated porous media was applied to predict the frequency dependencies of the phase velocity and the attenuation coefficient for the fast wave in water-saturated sandy sediment. Measurements of the phase velocity and the attenuation coefficient were performed over a frequency range from 0.5 to 1.0 MHz for water-saturated sandy sediment with a mean grain diameter of 400 μm and a porosity of 40 %. The experimental results revealed that the phase velocity exhibited a slightly negative dispersion linearly with the frequency and that the attenuation coefficient increased almost linearly with the frequency. The measurements were in good agreement with the model predictions over the frequency range covered here. Further studies will be required in frequency ranges not covered by existing data in order to establish completely the adequacy of the MBA model. In the present study, the modified Biot-Attenborough (MBA) model for acoustic wave propagation in fluid-saturated porous media was applied to predict the frequency dependencies of the phase velocity and the attenuation coefficient for the fast wave in water-saturated sandy sediment. Measurements of the phase velocity and the attenuation coefficient were performed over a frequency range from 0.5 to 1.0 MHz for water-saturated sandy sediment with a mean grain diameter of 400 μm and a porosity of 40 %. The experimental results revealed that the phase velocity exhibited a slightly negative dispersion linearly with the frequency and that the attenuation coefficient increased almost linearly with the frequency. The measurements were in good agreement with the model predictions over the frequency range covered here. Further studies will be required in frequency ranges not covered by existing data in order to establish completely the adequacy of the MBA model.

이익조정의 형태에 관한 연구

李康一,千宗栗 嶺南大學校 産經硏究所 2000 産經硏究 Vol.8 No.-

본 연구는 우리 나라에서 매년 이익유연화 이외에 빅베쓰(big bath) 형태의 이익조정이 일정 부분 발생하고, 기업이 빅베쓰를 활용하는 빈도가 경기불황이 심해짐에 따라 늘어나는 지를 실증적으로 검토하였다. 국내의 이익조정에 관한 선행연구는 지금까지 이익유연화만을 다루고 있고 빅베쓰와 관련된 연구는 없었다. O'Glove(1987)는 주로 경영진의 교체시점에 자주 사용되는 빅베쓰 형태의 이익조정이 아주 일반화된 현상이고, 자본시장은 빅베쓰를 통해 기업의 재무상태가 정상적으로 회복되는 것으로 간주하여 빅베쓰를 취하는 기업에 대해 호의적인 반응을 보인다고 주장하였다.Sundedr(1997)는 경영자가 통제할 수 없는 요인에 의해 이익 수준이 전기 대비 급격히 악화되거나, 일정 기간 누적된 이익유연화의 효과를 해소시켜야 할 필요성이 대두되거나, 새로운 최고경영진이 영입되어서 그 해의 나쁜 영업실적을 전임 최고경영진의 잘못으로 돌릴 수 있는 여건이 조성되는 경우 빅베쓰가 활용될 수 있다고 설명하고 있다. 1992년부터 1997년까지의 기간에 한국증권거래소에 상장되어 있는 12월 결산법인 중 금융, 보험, 증권업 및 건설업을 제외한 제조업에 속한 394개 기업을 대상으로 수행한 실증분석에 따르면, 1994년부터 1997년까지 4년간 매년 5% 이상의 기업이 빅베쓰 형태의 이익조정을 활용하고 있는 것으로 나타났다. 또한 1994년(7.1%)과 1995년(5.1%)에 비하여 경기가 나빠지기 시작한 1996년(11.7%)과 IMF 구제금융을 신청한 1997년(16.8%)에는 빅베쓰를 활용하는 빈도가 늘어나 경기가 악화될수록 빅베쓰 형태의 이익조정을 취하는 회사의 수가 늘어나는 것으로 나타났다.

Relationships of Bone Density with Quantitative Ultrasound Parameter in Bovine Cancellous Bone

이강일 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.1

The present study aims to investigate the relationships of bone density with quantitative ultrasound (QUS) parameters measured in transmission and backscatter modes in bovine cancellous bone. The speed of sound (SOS), the normalized broadband ultrasound attenuation (nBUA), the broadband ultrasound backscatter (BUB) and the integrated reflection coefficient (IRe) were measured for 35 specimens obtained from proximal ends of seven bovine tibiae. The highest correlation coefficient was observed for SOS (r = 0.75, p < 0.001). Similarly, nBUA was significantly correlated with density (r = 0.71, p < 0.001). In contrast, BUB and IRe were less correlated with density than transmission QUS parameters, but still significantly (r = 0.63 and 0.65, respectively, all p < 0.01). A multiple regression analysis was used to find optimal models for the prediction of apparent bone density by using linear combinations of SOS, nBUA, BUB and IRe, with density as an independent variable and 2,3 and 4 QUS parameters as dependent variables (r = 0.77 - 0.88, all p < 0.001). The results suggest that the analysis of multiple QUS parameters can contribute to improving the efficacy of QUS procedures in the diagnosis of osteoporosis beyond the established value of SOS and nBUA.

침투압을 이용한 급속압밀시험 : 방법 및 검증

이강일,도브로슬리브 지니다르씨스,김태형 한국지반공학회 2009 한국지반공학회논문집 Vol.25 No.4

A continuous, fast, and convenient experimental method, replacing recent tests such as standard oedometer or self weight consolidation test, is needed for the determination of the consolidation behavior of unformed soft soils. This study introduced the seepage induced fast consolidation test using the flow pump technique. It can obtain the consolidation characteristics of unformed soft soils conveniently and fast. The seepage induced consolidation test apparatus consists of a modified triaxial cell, differential pressure transducer, flow pump, and displacement transducer. The test continuously proceeds with starting seepage forces induced consolidation, loading consolidation, and permeability test on the same sample. In addition, this test result was compared with the standard oedometer test result to make this method valid. From this study it was found that this method is a convenient and time saving effective method for obtaining data required for calculation of consolidation settlement of unformed soft soils.

전자빔 증착법으로 성장한 NiO 박막의 전기적, 전자구조 및 광학적 특성

이강일,유스라마덴니,강희재,박남석 한국물리학회 2014 새물리 Vol.64 No.5

NiO thin films having 50 nm thickness were grown by using e-beam evaporation at room temperature, after which in-situ post-annealing was carried out at temperatures of 100℃, 200℃ and 300℃ for 30 minutes. The electrical, electronic structure and optical properties of the NiO thin films were obtained via Hall measurements, X-ray photoelectron spectroscopy (XPS), reflection electron energy loss spectroscopy (REELS), and UV spectrometer. The electrical properties of the NiO thin films grown at room temperature and post-annealed at 100℃ showed p-type semiconducting properties, and the average transmittance in the visible region was more than 70%. These results showed that NiO thin films should have applications as p-type transparent thin-film semiconductors. To the contrary, NiO thin films post-annealed at temperatures over 200℃ showed n-type semiconductor properties, and the average transmittance in the visible region was drastically decreased due to the formation of Ni-metal bonding. 전자빔증착법 (electron-beam evaporation)을 이용하여 유리 기판에 50 nm의 NiO 박막을 성장시킨 후 진공용기 내에서 100℃, 200℃, 300℃ 온도로 후 열처리를 하였으며, 박막의 전기적, 전자구조 및 광학적 특성을 홀 측정, 광전자 분광법, 반사 전자 에너지 손실 분광법 및 UV-spectrometer 실험 통하여 연구를 하였다. 실온 및 100℃로 후 열처리를 한 박막의 경우 p형 반도체 특성의 전기적 특성을 나타내었으며, 투과도 또한 가시광 영역에서 70%이상의 투과율을 나타내었으며, 이는 p형 투명전자소자로의 응용이 가능하다는 것을 보여주었다. 반면 200℃, 300℃ 온도로 후 열처리 한 박막의 경우, 표면에 Ni 금속 결합의 생성으로 n형 반도체 특성으로 변화하였으며, 투과율 또한 급격히 감소하는 것으로 나타내었다.

소아 Guillain-Barre 증후군에 대한 임상적 고찰

이강일 순천향대학교 1987 논문집 Vol.10 No.2

Auther reviewed the medical records of 21 patients (22 cases) under 15 years of age who had been treated with the diagnosis of Guillain-Barre syndrome. And the following results were obtained : 1) Of the twenty-two cases, thirteen cases were male and 9 cases female. The age incidence was peak in preschool age group. And the highest seasonal incidence was noted during in summer. 2) Twelve cases (54.5%) had preceding illness. 3) On admission all of them complained the muscular weakness of extrimities. 4) The albuminocytologic dissociation of cerebrospinal fluid were detected in seventeen cases (80.9%) and remaining four cases were not found the increment of protein level on CSF until discharge. 5) Fourteen cases (63.6%) were improved and 6 were dead. In survivors, almost improvement was started within 1 month, but several months were spent until complete recovery. 6) Ten cases had complication during treatment, most commonly being respiratory tract problems. 7) In this study, corticosteroid was not effective in treatment of Guillain-Barre syndrome.

날씨파생상품 가격 데이터를 활용한 기후변화 영향평가

이강일,한택환 한국경영학회 2009 한국경영학회 통합학술발표논문집 Vol.2009 No.08