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Failure Modes in Piled Embankments (말뚝으로 지지된 성토지반의 파괴형태)

  • 홍원표;윤중만;서문성
    • Journal of the Korean Geotechnical Society
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    • v.15 no.4
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    • pp.207-220
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    • 1999
  • Model tests were performed to investigate the failure modes in embankments on soft ground supported by piles with cap beams. In the model tests, Jumunjin standard sand was placed on simulated cap beams and soft ground. The cap beams are placed perpendicular to the longitudinal axis of the embankment. The colored sand and the Jmniin standard sand were placed one after the other above cap beams and soft ground to make lateral stripes with 3mm thickness in the embarkment. The colored sand was prepared by coating the Jumunjin sand with black lead powder. The photographs illustrate the two characteristic modes of failure in embarkments. One is the soil arching failure and the other is the punching shear failure. The failure mode depends on the height of embankment and the space between cap beams. That is, if the embankment is high enough compared with the space between cap beams, it will fail in arching failure. On the other hand if the embarkment is relatively low or the space between piles is too wide, it will fail in punching shear failure. The soil arching develops in embarkment as a semicylindrical arch with a thickness equal to the width of the cap beam. And the soil wedge developed above the cap beams remains intact during both arching and punching failures. The boundary of punching shear failure of the displaced soil mass can be defined on the basis of observation of the photographs.

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Comparative Study on the Urohyal of the Subfamily Gobioninae of Korea (한국산(韓國産) 모래무지아과(亞科)(Gobioninae) 어류의 미설골(尾舌骨)에 대한 비교연구)

  • Kim, Ik-Soo;Kang, Eon-Jong
    • Korean Journal of Ichthyology
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    • v.1 no.1_2
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    • pp.24-34
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    • 1989
  • We reexamined the skulls of 14 gobionine genera of Korea to study taxonomic status of Gobioninae. The character transformation series found in the morphology of urohyal was very distinct among other skeletal characters. The gobioninae fishes of Korea were divided into 4 groups based on their morphology of urohyal as follows ; 1. Coreoleuciscus, Gnathopogon group ; The horizontal plate of urohyal has a ellipse shape with posterior edge wedged and the length is longer than that of vertical plate. 2. Hemibarbus, Squalidus group ; The horizontal plate has a elongated rhombeus shape with posterior edge pointed and the length is shorter than that of vertical plate. 3. Sarcocheilichthys, Pseudopungtungia, Pseudorasbora, Pungtungia group ; the horizontal plate has a expanded rhombeus shape, the length is longer than that of vertical plate, the hypohyal attatchment is not bifurcated, and the profile of the horizontal and vertical plate curved ventrally. 4. Ladislavia, Gobiobotia, Abbottina, Hicrophysogobio, Pseudogobio, Saurogobio group ; The horizontal plate has a pin or wedge shape expanded anteriorly, the length is shorter than that of vertical plate, and the hypohyal attatchment is thickened laterally. This results agreed with those by the adductor mandibulae complex, the geniohyoideus of cephalic muscles, and the cephalic-lateral line canals.

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Correlations between Axial Rotation of Toric Soft Contact Lenses and Corneal Eccentricity according to the Wearing Time and Gaze Directions (착용시간 및 응시방향에 따른 토릭소프트콘택트렌즈의 축 회전과 각막이심률과의 상관관계)

  • Seo, Woo Hyun;Kim, So Ra;Park, Mijung
    • Journal of Korean Ophthalmic Optics Society
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    • v.21 no.1
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    • pp.35-45
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    • 2016
  • Purpose: The present study was aimed to investigate the effect of corneal eccentricity on the axial rotation when wearing toric soft contact lenses were worn for certain time and changing the gaze directions. Methods: Toric soft contact lenses with double thin zone design applied on 85 of with-the-rule astigmatic eyes. Then, rotational direction and amount of contact lenses were measured after 15 minutes and 6 hours of lens wear. The difference was further compared and analyzed according to corneal eccentricity. Results: The rotation of toric lens showed a tendency to rotate to temporal direction in all gaze directions except temporal-upper direction in all groups of corneal eccentricity. The amount of lens rotation in the frontal gaze direction exhibited a negative correlation since the amount was decreased with increasing corneal eccentricity after both 15 minutes and 6 hours of lens wearing. In many cases, the cornea with small eccentricity also showed the lens rotation larger than $10^{\circ}$. The difference in rotational amount after 15 minutes of toric lens wear was small according to the corneal eccentricity however, the change of rotational amount of contact lens according to corneal eccentricity was shown after 6 hours of lens wear. Conclusions: The present study revealed that the amount of axial rotation was largely varied according to the wearer's corneal eccentricity when wearing toric lens and the rotational amount after certain time of lens was also affected by corneal eccentricity. Thus, it is suggested that the selection of toric soft contact lenses based on corneal eccentricity is necessary.

Analysis of Rock Slope Stability for Natural Slope and Cut Slope of Gneiss Area in Andong, Korea (편마암지역 자연사면.절취사면의 안정성 분석 사례)

  • Kim, Man-Il;Bae, Du-Won;Kim, Jong-Tae;Chae, Byung-Gon;Jeong, Gyo-Cheol
    • The Journal of Engineering Geology
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    • v.17 no.2 s.52
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    • pp.289-297
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    • 2007
  • Slope failure that is occurred by rainfall generates a lot of property damages and loss of lives. Slope stability management and reinforcement countermeasure can be attained through continuous monitoring about various slope types that adjoin in human's life for reducing slope failure from natural and artificial cut slope hazards. The study area is rock slope that is consisted of gneiss, and large scale joint set is ranging by fault activity. This rock mass is exposed during long period and has lithological weathering property of weathered rock or soft rock. In-situ investigation carried out after divide by natural slope and cut slope. As a result, the natural slope appeared to high possibility of planar failure and wedge failure in few joint points that main joint set is formed. On the other hand, slope failure conformation in cut slope was superior only wedge failure occurrence possibility in eight joint points. In result of numerical analysis using SLIDE 2D, the minimum safety factor was analyzed slope stability for cut slope relatively low than natural slope in this study.

Science Teachers' Brain activation and functional connectivity during scientific observation on the biological phenomena (생명현상에 대한 과학적 관찰에서 나타나는 과학 교사들의 두뇌 활성 및 기능적 연결)

  • Lee, Jun-Ki;Byeon, Jung-Ho;Kwon, Yong-Ju
    • Journal of The Korean Association For Science Education
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    • v.29 no.6
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    • pp.730-740
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    • 2009
  • The purpose of this study was to investigate secondary science teachers' brain activation and functional connectivity during scientific observation on the biological phenomena. Twenty six right-handed healthy science teachers volunteered to be in the present study. To investigate science teachers' brain activities during the tasks, 3.0T fMRI system with block design was used to measure BOLD signals in their brains. The SPM2 software package was applied to analyze the acquired initial image data from the fMRI system. The results have shown that the left inferior frontal gyrus, the bilateral superior parietal lobule, the left inferior parietal lobule, the left precuneus, the left superior occipital gyrus, the right middle occipital gyrus, the right precuneus, the left inferior occipital gyrus and bilateral fusiform gyrus were significantly activated during participants' scientific observation. The network model consisted of eleven nodes (ROIs) and its ten connections. These results suggested the notion that scientific observation needs a connective cooperation among several brain regions associated with observing over just a sensory receiving process.

Evaluation of Beam Modeling Using Collapsed Cone Convolution Algorithm for Dose Calculation in Radiation Treatment Planning System (방사선치료계획시스템의 Collapsed Cone Convolution 선량계산 알고리듬을 이용한 빔 모델링의 정확성 평가)

  • Jung, Joo-Young;Cho, Woong;Kim, Min-Joo;Lee, Jeong-Woo;Suh, Tae-Suk
    • Progress in Medical Physics
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    • v.23 no.3
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    • pp.188-198
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    • 2012
  • This study aims to evaluate the accuracy of the collapsed cone convolution (CCC) algorithm for dose calculation in a treatment planning system (TPS), CorePLAN$^{TM}$. We implemented beam models for various setup conditions in TPS and calculated radiation dose using CCC algorithm for 6 MV and 15 MV photon beam in $50{\times}50{\times}50cm^3$ water phantom. Field sizes were $4{\times}4cm^2$, $6{\times}6cm^2$, $10{\times}10cm^2$, $20{\times}20cm^2$, $30{\times}30cm^2$ and $40{\times}40cm^2$ and each case was classified as open beam cases and wedged beam cases, respectively. Generated beam models were evaluated by comparing calculated data and measured data of percent depth dose (PDD) and lateral profile. As a result, PDD showed good agreement within approximately 2% in open beam cases and 3% in wedged beam cases except for build-up region and lateral profile also correspond within approximately 1% in field and 4% in penumbra region. On the other hand, the discrepancies were found approximately 4% in wedged beam cases. This study has demonstrated the accuracy of beam model-based CCC algorithm in CorePLAN$^{TM}$ and the most of results from this study were acceptable according to international standards. Although, the area with large dose difference shown in this study was not significant region in clinical field, the result of our study would open the possibility to apply CorePLAN$^{TM}$ into clinical field.

Failure Types in Rock Slopes According to Geological Characteristics (지질특성에 따른 암반사면 붕괴유형연구)

  • 정형식;유병옥
    • Geotechnical Engineering
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    • v.12 no.6
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    • pp.37-50
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    • 1996
  • In this study, we collected data through the investigation of rock slopes of highway. By analyzing the collected data, the main factors of rock slope failure were studied. We studied on the failure types and scales according to rock types and geological structures in many rock slopes of highway. As a result, it was shown that many failed slopes were distributed in the areas of Cretaceous sedimentary rocks of south-eastern part in the Korean Peninsula and the Gneiss Complex in both Kyonggi-Do and Kangwon-Do. According to rock types, the following slope failure types were shown : that igneous rocks had the types of rock fall, plane failure, soil erosion and circular failure but had low failure frequency, and sedimentary rocks had predominantly the type of plane failure. Metamorphic rock showed the types of circular failure, wedge failure and plane failure due to poor rock qualities . According to geological structures, the following slope failure types were shown slope failure in igneous rocks was caused by joints, and in sedimentary rocks by bedding plane, and in metamorphic rocks by faults and poor rock qualities.

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A Case of Pulmonary Alveolar Proteinosis with Spontaneous Resolution (자연 소실된 폐포단백증 1예)

  • Nam, Seung Bum;Park, Kwang Young;Lee, Ho Jin;Jung, Jae Wook;Choi, Yoon Hee;Kim, Hyo Seok;Kim, Cheol Hyeon;Lee, Jae Cheol
    • Tuberculosis and Respiratory Diseases
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    • v.63 no.3
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    • pp.294-298
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    • 2007
  • Pulmonary alveolar proteinosis is a rare disorder that is characterized by the abundant accumulation of surfactant-derived material within the alveolar spaces and distal bronchioles. Although the findings of homogenous ground-glass opacities overlaid by thickened septa, which form a "crazy paving" pattern on high-resolution computed tomography, can assist in making a diagnosis, a lung biopsy is usually required. This disorder has a variable clinical course, from spontaneous resolution to respiratory failure and death. While a whole lung lavage has been the standard treatment since the early 1960s, GM-CSF therapy has been attempted based on the recently suggested pathogenetic mechanism. We report a case of pulmonary alveolar proteinosis that resolved spontaneously after an open lung biopsy.

Emotional experiences of baseball fans at winning and losing games: An fMRI approach (경기 승패에 따른 야구팬들의 정서경험: fMRI연구)

  • Park, Hye-Ju;Yoo, Ho-Sang
    • Korean Journal of Cognitive Science
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    • v.21 no.3
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    • pp.429-446
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    • 2010
  • This study is to examine if emotional valance depending upon the result of baseball game(losing or winning) of subjects' favorite team yields hemispheric asymmetry measured by fMRI. Subjects were twelve fans of the Samsung Lions baseball team. The brain activations have been observed while they watched winning and losing scenes of their favorite team. As a results of the experiment, those who watched winning scenes showed the activation of the left and right cuneus, right inferior occipital gyrus, right inferior frontal gyrus, left amygdala, right parahippocampal gyrus, left uncus, left cingulate gyrus, left inferior temporal gyrus, right middle temporal gyrus, left declive, left culmen. On the contrary, those who watched losing scenes showed the activation in the right middle frontal gyrus, left anterior cingulate, left sub-gyral, left lentifomrm nucleus, left thalamus, left claustrum, left insula. The evidence of hemispheric asymmetry from this study has not been demonstrated and activation in amygdala observed during watching winning scene has not been observed in losing scene. Therefore more in-dept research is required about defeat stimuli induction.

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Estimation of Icebreaking Forces and Failure Length of Ice Rubbles on Infinite Ice Sheet (무한 빙판에서의 쇄빙력과 파단 빙편의 크기 예측)

  • Choi, Kyung-Sik;Lee, Jin-Kyoung;Kim, Hyun-Soo;Chun, Ho-Hwan
    • Journal of the Society of Naval Architects of Korea
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    • v.41 no.6
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    • pp.75-83
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    • 2004
  • Ice rubble pieces broken by the bow impact load and side hull of an icebreaking vessel usually pass along the ship's bottom hull and may hit the propeller/rudder or other stern structures causing serious damage to ship's hull . Therefore it is important to estimate the size of broken ice pieces during the icebreaking process. The dynamic interaction process of icebreaker with infinite ice sheet is simplified as a wedge type beam of finite length supported by elastic foundation. The wedge type ice beam is leaded with vertical impact forces due to the inclined bow stem of icebreaking vessels. The numerical model provides locations of maximum dynamic bending moment where extreme tensile stress arises and also possible fracture occurs. The model can predict a failure length of broken ice sheet given design parameters. The results are compared to Nevel(1961)'s analytical solution for static load and observed pattern of ice sheet failure onboard an icebreaker. Also by comparing computed failure length with the characteristic length, the meaning of ice rubble sizes is discussed.