• Geotechnical Engineering
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• v.14 no.5
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• pp.89-110
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• 1998

Variations of backfill load on the metal-polyethylene composite( MPC ) pipes buried in various trenches backfill afterward were investigated in this paper. The backfill loads obtained by the finite element method( FBM ) were compared with those calculated by the well-known MarstonBpangler(M-5) theory. The reliability of the finite element analysis used in this study was examined by an inaitu best for the buried pipe. The backfill lords and deflections on the real-size pipe buried on-site were measured while increasing the backfill height. In addition, further investigations were made for the variations of the backfill loads as a function of several important parameters such as the backfill soil type, bach. height$(\leq4.0m)$, diameter of the pipe$(B.$1.0m)$, and trench width($\leq 3.0 B_c$). It is confirmed that the M-S theory predicts reasonably well the backfill loafs of the MPC of the M-S backfill coils be 0.13 and 0.15 for the SC and SM coils in the D unman soil model, respectively. The load ratio, Wu-s/WwgM for a narrow trench varies negligibly with the back(111 height but fiends to increase for a wide trench. The ratio increases with increasing diameter of the pipe for a narrow trench while decreasing for a wide trench. It is also found that the ratio generally decreases as the degree of compaction increases and BM soil exhibits larger load ratio than that of SC soil.

• Journal of the Korean Arthroscopy Society
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• v.12 no.1
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• pp.40-44
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• 2008

Purpose: The purpose of this study was to report the real geometry of Resident's ridge doing in anterior cruciate ligament reconstruction Materials and Methods: From Jan 2007 to Aug 2007, 48 cases which had normal distal femoral condyle analyzed with Multidetector-Row Computed Tomography. Resident's ridge was defined as change of height above 1 mm in lateral wall of intercondylar notch. Anterior-posterior length of intercondylar notch, length and height of Resident's ridge, distance of Resident's ridge from posterior cortex were estimated with 3-D reconstruction using $Lucion^{(R)}$ program. Results: Cases were $59{\pm}16$ years olds and male was 16 cases, female was 32 cases. 9 cases had no Resident's ridge, anterior-posterior length of intercondylar notch was $25.4{\pm}3.5$ mm, average of length and height of the Resident's ridge was $8.2{\pm}2.6,\;3.5{\pm}1.5$ mm. Distance of the Resident's ridge from posterior cortex was $7.6{\pm}2.6$ mm. Conclusion: Resident's ridge was used as landmark in anterior cruciate ligament reconstruction, which presented in many cases and which had distinct length and height.

• Korean Journal of Environmental Biology
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• v.38 no.2
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• pp.315-322
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• 2020

A 210-day experiment was conducted to examine the effects of starvation on survival, the gonadosomatic index (GSI), hepatosomatic index (HSI), and the intestinosomatic index (ISI), and histological changes in the renal tubule epithelium, midgut epithelium, and hepatocytes in Far Eastern catfish (Silurus asotus). The survival rate decreased to 92.2±0.47% in the fed group and 74.4±2.59% in the starved group during the 210-day experimental period. GSI, HSI, and ISI were lowest in the starved group (p<0.05). The hepatocyte nuclear area, hepatocyte cell area, the nuclear height of the midgut epithelium, and the nuclear height of the kidney were highest in the fed group (p<0.05). The hepatocyte nuclear area, nuclear height of the midgut epithelium, and nuclear height of the kidney were lowest in the starved group(p<0.05). The numbers of melano-macrophages (MMs) found in the kidney cells increased during starvation in this species. This suggests that thinner body cavity regions, the contraction of hepatocyte nuclear sites, and the spreading of kidney cell MMs in this species could be used as alternative indicators for identifying starvation conditions. Therefore, the results from our study provide accurate indications of the nutritional status of Far Eastern catfish.

• Journal of Periodontal and Implant Science
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• v.35 no.3
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• pp.609-621
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• 2005

1. 목적 Osteotome 상악동거상술(Bone Added Odteotome Sinus Floor Elevation ; 이하 BAOSFE) 과 동시에 식립한 임프란트($Br{\aa}nemark$, ITI)의 예상 생존율에 대해 현재까지 정확히 알려진 바는 없었으며, $Br{\aa}nemark$ Ti-Unite 과 ITI SLA 임프란트의 표면에 대한 비교 연구 또한없었다. 이번 연구는 BAOSFE 술식과 동시에 식립한 $Br{\aa}nemark$ Ti-Unite 과 ITI SLA 임프란트의 임상 결과를 비교, 평가하고 초기 치유기간 동안의 이식골 높이의 변화를 방사선학적으로 관찰하여 두 가지 임프란트 시스템을 비교해 보고자 한다. 2. 방법 위축된 상악 구치부를 갖는 22명의 환자를 대상으로, BAOSFE술식과동시에 $Br{\aa}nemark$ Ti-Unite(11명, 13 임프란트)임프란트와 ITI SLA(11명, 18 임프란트)임프란트를 식립하였다. 수술 전, 임프란트 식립 직후, 술후 6개월의 파노라마 방사선 사진을 촬영하여 비교 및 평가에 사용하였다. 각 임프란트 시스템의 생존율을 측정하고, 술전 상악동저 높이와 식립된 임프란트 길이를 참고하여 이식골 높이의 방사선학적 변화를 평가하였다. 3. 결과 평균12개월의 추적기간 결과, $Br{\aa}nemark$ Ti-Unite 임프란트의 생존율은 100%(13/13 임프란트)이었으며, ITI SLA 임프란트의 생존율은 94.4%(17/18 임프란트)이었다. 초기 치유 기간인 6개월 동안 평균 이식골 높이의 감소는 $Br{\aa}nemark$ Ti-Unite 임프란트에서 0.67mm(10.73%), ITI SLA 임프란트에서는 0.55mm(8.18%)로 나타났다. 두 가지 임프란트 시스템 간의 유의성 있는 차이는 보이지 않았다. 4. 고찰 BAOSFE 술식과 동시식립한 $Br{\aa}nemark$ Ti-Unite 과 ITl SLA 임프란트는 위축된 상악 구치부를 갖는 환자에서 효과적인 치료방법이 될 수 있으며, 임프란트 표면에 따른 이식골의 치유 반응은 두 가지 임프란트 시스템에서 유사한 양상으로 일어남을 알 수 있었다.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.1058-1065
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• 2017

Amino acid based surfactants as protein-surfactants is eco-friendly compound. So, amino acid based surfactants is expected as next generation surfactants. Amino acid based surfactants has high biodegradability, low toxicity and surface active properties. In this experiment, amino acid based surfactants, cocoyl glycine, was synthesized by glycine and triglyceride such as coconut oil and palm oil. And it was tested the surface tension, emulsifying properties, foam stability and HLB value. The synthesized surfactants was confirmed by FT-IR. Surface tension of surfactants synthesized by coconut oil on diluted aqueous solutions of surfactants was 31.2 dyne/cm at $1.0{\times}10^{-4}mol/L$. Surface tension of surfactants synthesized by palm oil on the diluted aqueous solutions of surfactants was 42.1 dyne/cm at $3.2{\times}10^{-5}mol/L$. Foam stability measured the foam height as time passed. Initial foam height of surfactants synthesized by coconut oil is 14.5 cm, and 10.7 cm after five minutes. Initial foam height of surfactants synthesized by palm oil is 3.0 cm, and 2.8 cm after five minutes. Foam height of surfactants synthesized by coconut oil was higher than surfactants synthesized by palm oil. But foam stability of surfactants synthesized by palm oil was better than surfactants synthesized by coconut oil. The emulsifying properties of synthesized surfactants are observed in benzene and soybean oil and emulsifying properties in organic solvent is better than in soybean oil.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.257-257
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• 2017

본 연구는 기상이변의 영향으로 지속적으로 발생되고 있는 댐 저수지 붕괴에 대한 원인 분석과 기존의 관련 연구 및 지침 등을 비교 분석하여 현재 실무에서 적용되고 있는 댐 저수지 비상대처계획(EAP) 수립 대상 기준에서 제외되는 시설물의 붕괴 가능성 평가를 통해 EAP 수립 대상의 적정 범위를 제시하고자 하였다. 이를 위해 본 연구에서는 시설물의 붕괴 가능성에 대한 정량적 판단 기준을 각 요인별로 제시하고, EAP 수립 대상에서 제외되는 댐 저수지를 대상으로 붕괴 가능요인을 적용하여 3개 이하의 붕괴요인에 해당될 경우 저위험군, 4개 및 5개의 붕괴요인에 해당될 경우 중위험군과 고위험군으로 각각 분류하여 시설물 붕괴 위험성 정도에 따른 적절한 대응이 이루어질 수 있도록 제안하였다. 댐 저수지 붕괴 사례 분석을 통해 도출된 붕괴 가능성의 주요 요인으로는 저수용량, 제체 높이, 준공 경과연수, 우심피해 및 지진피해 잠재지역이 포함되며, 각 요인별 객관적인 판단기준은 댐 저수용량의 경우 EAP 법적 수립기준 및 과거 붕괴사례 등의 분석을 토대로 붕괴사례 61개소 중에서 약 88%를 차지하는 저수용량 10만톤을 선정하였으며, 댐 높이의 경우 댐의 파괴양상(이종태, 1987)에서 제시한 댐 붕괴부 특성과 미국주댐안전협회(ASDSO: American Society of Dam Safety Official) 학술지인 Dam Safety(2006) 등에서 제안한 기준을 기존의 댐?저수지 붕괴사례에 적용하여 댐 붕괴폭과 댐 높이의 상관관계 분석 결과를 바탕으로 댐 높이 8m 이상을 적정 범위로 고려하였다. 준공 경과연수의 경우에는 국민안전처 "재해위험저수지 댐 관리 지침" 타당성 평가기준인 '시설노후도' 기준과 한국시설안전공단 사회간접자본 노후화 기준에 해당하는 경과연수 기준을 토대로 30년 이상을 기준으로 선정하였으며, 우심피해 및 지진피해 잠재지역은 국민안전처 재해연보(2014)를 기준으로 과거 10년 동안의 우심피해 발생 지역과 기상청 국내 지진 규모 10위권 내에 포함되는 지역을 고려 대상으로 하였다. 본 연구에서 도출한 시설물 붕괴 가능성에 대한 판단기준을 국민안전처에서 고시한 EAP 수립 대상에서 제외되는 지자체 재해위험저수지 354개소에 적용해 본 결과, 저위험군 16개소, 중위험군 5개소, 고위험군 2개소로 각각 조사되었다. 저위험군은 전문 시설물 관리자에 의한 주기적인 시설물 점검 및 관찰이 필요할 것으로 사료되며, 중 고위험군에 속하는 시설물의 경우 본 연구의 결과를 바탕으로 시설물 하류지역의 실질적인 인명 및 경제적 피해 가능성에 대한 보다 면밀한 조사를 통해 EAP 수립 대상 포함여부를 결정하여야 할 것으로 판단된다.

• Food Science and Preservation
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• v.21 no.6
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• pp.838-843
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• 2014

In this study, near-infrared spectroscopy was used to observe the drying non-uniformity of vegetables such as spring onions, onions, and garlic, which are commonly used for seasoning. For the warm-air convection drying method, the vegetables showed drying non-uniformity, which is due to the unevenness of the wind temperature and humidity depending on the height and position of the drying tray. The second derivative spectra between the vegetable samples with different drying degrees were compared. The peak at around 1,390~1,400 nm, which is assigned to weak hydrogen bonds of water, was changed during drying whereas the peak near 1,420 nm, which represents strong hydrogen (H-) bonds of water, was not changed, indicating that water with weak H-bonds evaporates first during drying, and that water with strong H-bonds remains after drying. The hyperspectral NIR imaging technique combined with principal-component analysis made it possible to discriminate the dried vegetables according to their drying degree.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.4
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• pp.391-395
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• 2018

Increasing demands for zirconia material in clinics, assessment of biocompatibility of zirconia is essential. In this article, a review of in vitro studies of zirconia compatibility was performed. Zirconia showed great biocompatibility at in vitro studies with various cell lines such as fibroblasts, osteoblasts, and lymphocytes. Many studies reported that zirconia caused no cytotoxicity or mutation. Zirconia also showed less bacterial adhesion. There were no adverse effects except for small reduced strength with in vitro study mimicking long-term exposure of body fluid. According to the study with ostoblast-like cells, zirconia could regulate genes of immunity, molecular transport, and cell cycle. Such gene regulating was considered as one of the reasons of zirconia biocompatibility. With biocompatibility of zirconia powders, in vitro studies had controversial conclusions. It seems that zirconia powders might have cytotoxicity.

• Korean Journal of Cognitive Science
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• v.15 no.2
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• pp.17-22
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• 2004

Two experiments were executed to investigate the effect of uniform connectedness systematically using the identification task of briefly exposed forms. Previous study observed negative repetition effected (i.e., NRE) in the identification task of two parentheses either connected or disconnected vertically, which was interpreted as an evidence against the hypothesis of uniform connectedness. Experiment I tested the hypothesis that NRE resulted from the Perceptual set or anticipating disconnected displays. Experiment 2 tested the hypothesis that NRE resulted from relatively shorter exposure time. Using partial report task asking participants to report only the cued target and whole report task asking them to report the whole pattern with only connected displays, experiment 1 observed NRE respectively. Experiment 2, with longer exposure time equivalent to 83% accuracy and response bias controlled by use of catch trials, obtained the same NRE. Those results seems to indicate that uniformly connected forms were processed analytically by perceivers without task demand and futhermore, the hypothesis of uniform connectedness as a principle of perceptual organization is not plausible.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.1
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• pp.104-110
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• 2007

Temperature rise characteristics of medium voltage class transformers and dielectric characteristics of its insulation oil according to the loading rate were investigated using the transformer that has thermocouples embedded in the windings. The hottest-spot of the transformer locates at about 2/3 height of the windings where they adjoin each other among the 3 phase windings. The temperature difference between the hottest-spot and top-oil is about $17[^{\circ}C]$ and the value keeps uniformly in short time after changing the loading rate. Capacitance of the oil varies in inverse proportion to temperature and the inclination rate is about -0.0106 that is not dependent on the aging rate. On the other hand the capacitance is increased depending on the aging rate, so the capacitance characteristics of the oil could be applied to the diagnostic technique.