• 한국농공학회지
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• 제30권3호
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• pp.38-50
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• 1988

carried out to present a rheology model which is able to treat time-dependent properties of clay. The results were summarized as follow ; 1. The slope (a(e1)) of deviator stress in strain rate test was independent on axial strain, and pore water pressure was decreased with increment of strain rate. 2. The pore water pressure in a stress relaxation condition was not changed when the strain rate before stress relaxation was 0.05%/min., but it was increased with increment of time when the strain rate before stress relaxation was 0.2%/min 3. The greater the stress condition (q/qmax) and the strain rate before creep test became, the greater the increment rate of axial strain in creep test became. 4. SEKIGUCHI's constitutive equation was slightly overpredicted while empirical equation proposed in the study was well coincided with measured values. 5. The constitutive equation induced by a strain function could be dealed with a behavior of the pore water pressure increased with increment of elapsed time after primary consolidation.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2002년도 춘계 학술발표회 논문집
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• pp.12-19
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• 2002

A high frequency level of Fourier amplitude relates with stress drop and seismic moment. When we can not use this relation owing to absence of digital earthquake data, stress drop and seismic moment can be determined from Peak Ground Velocity(PGV) and felt area. We have qualitatively evaluated the seismic characteristics using PGV, and Magnitude from the well determined felt area in seismological records of Korea(1978~2001) by Korea Meteorological Administration(KMA). Observed relations between felt area and magnitude in the Korean Peninsula are explained by attenuation(Q), and stress drops comparing with the previous researches on stress parameter. This results are preliminary work for the study of stress parameter using the relationship of high frequency lavel, PGV, and felt area.

• Structural Engineering and Mechanics
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• 제34권3호
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• pp.377-390
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• 2010

This paper studies fracture initiation direction of two parallel non-coplanar cracks of equal length. Using the dislocation pile-up modelling, singular integral equations for two parallel cracks subjected to mixed-mode loading are derived and the crack-tip field including singular and non-singular terms is obtained. The kinking angle is determined by using the maximum hoop stress criterion, or the ${\sigma}_{\theta}$-criterion. Results are presented for simple uniaxial tension and biaxial loading. The biaxiality ratio has a noticeable influence on crack growth direction. For the case of biaxial tension, when neglecting the T-stress the crack branching angle is overestimated for small crack inclination angles relative to the largest applied principal stress direction, and underestimated for large crack inclination angles.

• Journal of Electrical Engineering and Technology
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• 제5권4호
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• pp.592-596
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• 2010

In a multi-layer interior permanent magnet synchronous motor, the d- and q-axis parameters vary nonlinearly according to different load conditions, consequently changing the level of saturation. The flux-linkage of d- and q-axis conveys ripple characteristics resulting from mechanical structure and degree of magnetic saturation. If the calculated flux-linkage is correct, the torque using the Maxwell stress tensor method is the same torque calculated by the flux-linkage. However, discrepancy between results exists. In this paper, the d- and q-axis flux-linkage, in consideration of the ripple characteristic, is calculated. Simulation results are then compared with experimental results.

• Journal of Electrical Engineering and Technology
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• 제9권2호
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• pp.541-549
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• 2014

In this paper, an extended switched-inductor quasi-Z-source inverter (ESL-qZSI) with high boost voltage inversion ability is presented, which combines the SL-qZSI with the traditional boost converter, as well as improves the switched-inductor cell. Compared with the classic qZSI topologies, the proposed topology reduces the voltage stresses of capacitors, power devices and diodes for the same input and output voltage. Furthermore, the conversion efficiency is improved. The operation principle of the proposed topology is analyzed in details, which is followed by the comparison between the three topologies. In addition, the performance of the proposed topology is verified by simulations and experiments.

• 한국농림기상학회지
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• 제10권2호
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• pp.47-57
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• 2008

오존에 노출된 참나무속 5종의 오존에 대한 내성 능력을 평가하기 위하여 생리생화학적 변화를 조사하였다. 150ppb 오존에 노출된 참나무속 5종(상수리나무, 갈참나무, 대왕참나무, 졸참나무, 굴참나무)의 잎에서 엽록소 함량, 광합성 특성, MDA 함량 및 항산화효소 활성이 측정되었다. 엽록소, 카로테노이드 함량, 순광합성 속도 및 탄소고정효율은 오존 처리 후에 감소하였다. 오존에 노출된 수목의 총 엽록소 함량과 탄소고정효율의 감소율은 갈참나무의 경우 15%와 34% 였으며, 굴참나무의 경우 38.3%와 62.1%였다. MDA 함량은 오존 처리 하에서 증가하였으며, 상수리나무에서 140%까지 증가를 보였다. 상수리나무의 SOD 활성 증가율(60%)은 가장 높았으며, APX 활성은 굴참나무, 졸참나무, 상수리나무에서 증가를 보였다. 생리생화학적 반응을 기초로 한 참나무속 5종의 내성 능력은 갈참나무, 대왕참나무, 졸참나무, 굴참나무, 상수리나무 순이었다. 결론적으로 엽록소 함량, 광합성 특성, MDA 함량, 항산화효소와 같은 생리학적 지표들은 오존 스트레스에 대한 내성을 평가하기 위한 매우 중요한 지표들로 생각되며, 이러한 모수들은 서로 밀접한 관계를 가진다.

• Korea-Australia Rheology Journal
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• 제18권1호
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• pp.15-24
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• 2006

The first international inter-laboratory study, involving six laboratories, has been conducted to examine issues associated with yield stress measurements in suspensions. The initial focus of the project was to evaluate the reliability and reproducibility of several common yield stress measuring techniques employed in different laboratories and with different instruments. Aqueous suspensions of colloidal $TiO_2$ at concentrations of 40-70 wt% solids were used as the test fluids. A wide range of instruments and techniques employing both direct and indirect methods were used to determine the yield stress of the samples prepared according to a prescribed procedure. The results obtained indicated that although variations of results existed among different techniques, direct yield stress measurements using static methods produced more reliable and repeatable results than other methods. Variability of the yield stress measured using different techniques within any laboratory however was less significant than variability of the results among different laboratories. The nature and condition of the test suspensions was identified as the most likely factor responsible for the poor reproducibility of yield stress measurements from different laboratories.

• 간호행정학회지
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• 제13권2호
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• pp.184-190
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• 2007

Purpose: This study was undertaken in order to suggest self-leadership as a method for nurses to lower their job stress and enhance their job satisfaction. So the relations among self-leadership, job stress and job satisfaction were studied. Method: The subjects of study were 123 nurses who have been working in 2 general hospitals located in K city. The data were collected by Q & A and analyzed using descriptive statistics, Pearson's correlation coefficient, t-test, and ANOVA on SPSS Program. Result: Nurses got average 3.50, 2.64 and 3.12 points out of 5 in their self-leadership, job stress and job satisfaction respectively. The self-leadership was negatively correlated with job stress (r=-.429, p=<.001) while it is positively correlated with job satisfaction(r=.281, p=<.001). And job stress was negatively correlated with job satisfaction(r=-.574, p=<.001). Job stress had statistically significant differences according to age and marital status. Conclusion: In conclusion self-leadership is correlated with job stress and job satisfaction. It is recommend that hospital managers have to develop methods which enhance self-leadership of nurses.

• 한국융합학회논문지
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• 제11권9호
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• pp.73-81
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• 2020

본 연구의 목적은 20~30대 마라톤 동호회 활동 참가자들의 동호회 활동에 대한 인식을 탐색하는 데 있다. 연구 방법은 인간의 주관적 태도나 가치를 탐색할 수 있는 Q-방법론을 활용하였고, 수도권에서 마라톤 동호회 활동에 참여하고 있는 20~30대의 젊은 마라토너 30명을 대상으로 하였다. 연구결과 총 3개의 유형으로 분류되었다. 제1유형은 의미부여형으로, 신체활동과 고통 극복 그리고 런너스 하이를 경험하는 등 마라톤 활동의 본질에 의미를 두고 있다. 제2유형은 여가형으로, 일상에서 벗어나 여러 사람들과 마라톤이라는 공통의 취미를 즐기고 개인적 스트레스를 해소하는 것에 의미를 두고 있다. 제3유형은 동호회형으로, 다양한 특성을 가진 동호회원들과 관계를 맺고 동호회 활동을 통한 즐거운 축제를 즐기며 성취감과 개인의 건강 그리고 삶을 관리하는 것에 의미를 두고 있다. 이러한 결과는 개인의 주관성에 따라 마라톤의 의미가 몇 개로 유형화됨을 알 수 있고, 이는 젊은이들의 스포츠 문화의 경향을 이해하는 데 의미있는 시사점을 제공할 것이다.

• 한국산학기술학회논문지
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• 제17권1호
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• pp.572-584
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• 2016

본 연구는 인간의 주관성을 탐구할 수 있는 Q 방법론을 이용하여 여자간호사가 인식하는 남자간호사의 유형과 특성을 확인하고자 수행하였다. 35명의 P 표본에게 35개의 Q 표본을 9점 척도 상에 정규 분포의 형태로 분류하게 하였다. 수집된 자료는 PC-QUANL 프로그램으로 처리하였다. 연구결과, 남자간호사에 대한 인식은 3개의 유형으로 확인되었으며, 제1유형은 '발전 지향적 옹호형', 제2유형은 '현실적 비판형', 제3유형은 '보수주의적 수용형'으로 분류되었다. 각 유형 간 공통된 견해는 '남자간호사는 여성 집단의 고유한 특성으로 인해 스트레스를 받는다'로 나타났다. 본 연구결과는 세 가지 유형에 근거한 중재 프로그램을 개발하여 남자간호사에 대한 여자간호사의 인식을 향상시키는 데 기여할 것이다.