• Geomechanics and Engineering
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• 제15권6호
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• pp.1153-1160
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• 2018

Rockbursts, catastrophic events involving the violent release of elastic energy stored in rock features, remain a worldwide challenge for geoengineering. Especially at deep-mining sites, rockbursts can occur in hard, high-stress, brittle rock zones, and the associated risk depends on such factors as mining activity and the stress on surrounding rocks. Rockbursts are often sudden and destructive, but there is still no unified standard for predicting them. Based on previous studies, a new Bayesian multi-index model was introduced to predict and evaluate rockbursts. In this method, the rock strength index, energy release index, and surrounding rock stress are the basic factors. Values from 18 rock samples were obtained, and the potential rockburst risks were evaluated. The rockburst tendencies of the samples were modelled using three existing methods. The results were compared with those obtained by the new Bayesian model, which was observed to predict rockbursts more effectively than the current methods.

• 한국세라믹학회지
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• 제31권2호
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• pp.206-212
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• 1994

Effects of the film deposition process parameters on the properties such as deposition rate, etch rate, refractive index, stress and step coverage of plasma enhanced chemical vapor deposited (PECVD) tetraethylorthosilicate glass (TEOS) SiO2 film were investigated and analysed using SEM, FTIR and SIMS techniques. Increasing TEOS flow or decreasing O2 flow increased the deposition rate and the compressive stress of the oxide film but produced a less denser film. The deposition rate decreased owing to the decrease in the sticking coefficient of the TEOS and the O2 molecules onto the substrate Si with increasing the substrate temperature. Increasing the substrate temperature produced a denser film with a lower etch rate and the higher refractive index by lowering SiOH and moisture contents. Increasing the rf power increases the ion bombardment energy. This increase in energy, in turn, increases the deposition rate and tends to make the film denser. No appreciable changes were found in the deposition rate but the refractive index and the stress of the film decreased with increasing the deposition pressure. The carbon content in the plasma TEOS CVD oxide film prepared under our standard deposition conditions were very low according to the SIMS analysis results.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.381.1-381.1
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• 2014

In this study, we investigated the deposition behavior and the etch resistivity of plasma polymerized carbon hardmask (ppCHM) film with the variation of process temperature. The etch resistivity of deposited ppCHM film was analyzed by thickness measurement before and after direct contact reactive ion etching process. The physical and chemical properties of films were characterized on the Fourier transform infrared (FT-IR) spectroscope, Raman spectroscope, stress gauge, and ellipsometry. The deposition behavior of ppCHM process with the variation of temperature was correlated refractive index (n), extinction coefficient (k), intrinsic stress (MPa), and deposition rate (A/s) with the hydrocarbon concentration, graphite (G) and disordered (D) peak by analyzing the Raman and FT-IR spectrum. From this experiment we knew an optimal deposition condition for structure of carbon hardmask with the higher etch selectivity to oxide. It was shown the density of ppCHM film had 1.6~1.9 g/cm3 and its refractive index was 1.8~1.9 at process temperature, $300{\sim}600^{\circ}C$. The etch selectivity of ppCHM film was shown about 1:4~1:8 to undoped siliconoxide (USG) film (etch rate, 1300 A/min).

• 한국지진공학회논문집
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• 제21권5호
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• pp.205-213
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• 2017

The WUF-W moment connection is a pre-qualified connection that can be used for special moment frames specified in current seismic design specifications. Since the stress distribution near the connection varies according to access hole configuration, the cyclic performance of WUF-W connections is strongly affected by the access hole configurations. To evaluate the connection performance according to various access hole configurations, it is expensive to conduct experiments with many connection specimens. Instead, finite element analyses (FEA) can be performed. Throughout the FEA, stress and strain distribution in the connection can be monitored at each loading step. The purpose of this study is to construct nonlinear 3-dimensional FE models for accurately predicting the cyclic behavior of WUF-W connections. For predicting connection fracture using FEA, an appropriate response index detecting the incidence of connection rupture is proposed.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.369-376
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• 2000

Parameters that represent the characteristic of consolidation have been determined by the oedometer tests. They are varied by the process of sampling and transportation, accuracy of apparatus, process of sample trimming and the skill of engineers. Also, it is difficult to grasp what factor exert a influence on the parameters. In this study, Slurry Rowe Cell Tests were peformed to evaluate the disturbance. Using the plot of e - log p which obtained from Rowe Cell test results, we compared the swelling indexes at the stress relief and the last loading stage. With that result, we tried to presume the disturbance of the 330 oedometer tests. The plot of compression-swelling index at the stress relief considerably scattered but at the last step of load shows a correlations between them. And the plot of depth-p$\sub$c/ shows a correlation with the different swelling indexes, but not in the LL-p$\sub$c/. Consequently, it is considered that the disturbance of the consolidation tests can be presumed by the comparison of the difference of swelling index.

• Natural Product Sciences
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• 제12권3호
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• pp.150-152
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• 2006

The ethanol extract of Sida acuta Burm. (ALSA) whole plant was studied for its anti-ulcer activity against aspirin plus pylorous ligation induced gastric ulcer, HCl-ethanol induced ulcer, and water immersion stress induced ulcer (WISIU) in rats. We found that ALSA at a dose of 300 mg/kg, (orally) markedly decrease the incidence of ulcers in the first two models. ALSA showed reduction in gastric volume, free acidity, and ulcer index (53.69%). It has not reduced the total acidity significantly and no significant change in pH. It also showed 55.14% gastro protective activity, wheres standard drug sucralfate showed 94.85%. WISIU showed protection index 24.4%, whereas standard drug omeprazole (OMEZ) showed protection index 100%.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.784-787
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• 2003

Electrorheological(ER) and magnetorheological(MR) fluid-based dampers are typically analyzed using Bingham-plastic shear model under quasi-steady fully developed flow conditions. A Herschel-Bulkley constitutive shear flow relationship is that the linear shear stress vs. strain rate behavior of Bingham model is replaced by a shear stress that is assumed to be proportional to a power law of shear rate. This power is called the flow behavior index. Depending on the value of the flow behavior index number, varying degrees of post-yield shear thickening or thinning behavior can be analyzed. But it is not practical to analyze the damping force in a flow mode damper using Herschel-Bulkley model because it is needed to solve a polynomial equation. A useful guide is suggested to analyze the damping force in a damper using the Herschel-Bulkley model.

• 터널과지하공간
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• 제14권5호
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• pp.363-372
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• 2004

구마모토 안산암을 대상으로 이중 비틀림(DT) 시험을 통해 유도 홈의 단면 형상이 암석의 응력부식지수에 미치는 영향에 대하여 조사하였다. 정변위속도법에서 변위속도가 증가할수록 균열성장속도는 증가하지만 파괴인성계수는 평균 2.07 MN/m$^{3}$2/로 거의 일정하였다. 정변위법을 통하여 유도 홈의 형상이 사각형, 원형, 삼각형인 시험편을 이용하여 얻은 응력부식지수는 각각 평균 37, 36, 38로 홈의 형상에 관계없이 거의 일정한 값을 보이지만 표준편차는 삼각형 홈에서 가장 크게 나타났다. 암석의 DT시험은 중앙부에 유도 홈이 있는 시험편을 이용하는 것이 효과적이지만 광물의 평균입경 이상의 폭을 가진 사각형 단면의 홈을 이용하는 것이 가장 적절하다.

• 대한간호
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• 제31권5호
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• pp.72-87
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• 1992

This study was designed to develop and lest a structural model for paternal adaplation and family stress in the families with the handicapped children. A hypothetical model was constructed on the basis of family stress theory developed by McCubbin etc. The model included 6 theoretical concepts and 11 paths. For the purpose of the model testing, empirical data were collected from May to August, 1992. The subject of the study constituted 190 mothers whose children admitted in the five special schools and one privale institutes in Seoul and Choong Nam. In data analysis, SPSS PC+ and PC-LISREL 7.13 computer program were utilized for descriptive and covariance structure analysis. The results of lhe study were as follows. (1) Hypothetical model showed a good fit to the empirical data [Chi-square = 21.19 (df = 7, P = o. 003), Goodness of Fit Index=O.986, Adjusted Goodness of Fit Indes=0.946, Root Mean Square lesidual=0.048), Non Normed Fit Index = 0.80, Normed Fit Index=0.91]. (2) The results of Hypothesis testing indicated: 1) Social support(${\gamma}_11=.238$, T=2.352), Family Functioning(${\gamma}_12=.729$, T=5.957) had direct effects on situational definition. 2) life event stress(${\gamma}_23=.284$, T=5.220) had direct effects on the effect of the handicapped chid on the family. 3) Family functioning(${\gamma}_32=-.239$, T= -3.370) had direct effects on paternal adapation. From the above results, the significance of this study can be delineated as follows : The construction and testing of the comprehensive model seem to be the first trial in Korea. The model was supported by empirical dala. Thus it was suggested that model could be adequately applied to framily nusing care with the handicapped.

• 한국정보전자통신기술학회논문지
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• 제8권2호
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• pp.133-139
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• 2015

연구의 목적은 지적장애인 생활시설 입소자의 스트레스, 행동지수 요인이 삶의 만족도에 미치는 영향을 분석하고자 한다. 연구대상은 대전광역시 지적장애인 생활시설 지적장애인 200명을 대상으로 2014년 3월 5일부터 9월 22일 까지 설문조사를 실시하였다. 분석방법은 SPSS WIN 18.0, Amos 21.0 프로그램을 사용하여 t-test와 일원변량분석, 확인적 요인분석, 구조방정식을 실시하여 유의수준 5%에서 검증하였다. 연구결과는 첫째는 스트레스가 삶의 만족도에 영향을 미치지 않음을 알 수 있다. 둘째, 행동지수요인이 이용만족도에 영향을 미치지 않음을 알 수 있다. 셋째, 신체증상의 경우에 이용자 만족도에 의하여 삶의 만족도에 영향을 미치는 것을 알 수 있다. 향후 생활시설 지적장애인의 이용만족도와 일상생활 스트레스의 개선에 대한 정책적 기초자료에 활용이 요구된다.